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Title: Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 1 - "Châtelet" to "Chicago"
Author: Various
Language: English
As this book started as an ASCII text book there are no pictures available.
Copyright Status: Not copyrighted in the United States. If you live elsewhere check the laws of your country before downloading this ebook. See comments about copyright issues at end of book.

*** Start of this Doctrine Publishing Corporation Digital Book "Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 1 - "Châtelet" to "Chicago"" ***

This book is indexed by ISYS Web Indexing system to allow the reader find any word or number within the document.



Transcriber's notes:

(1) Numbers following letters (without space) like CO2 or C12H18 were

(2) Letters or fractions following an underscore, like A_{2/3} or V_k,
      were originally printed in subscript.

(3) Characters following a carat (^) were printed in superscript.

(4) The infinity sign is rendered as [oo].

(5) Side-notes were moved as titles to their respective paragraphs.

(6) The following typographical error have been corrected:

    Article CHATTERJI, BANKIM CHANDRA: "imagination and power of
      delineation had never been surpassed" 'never' amended from 'social'.

    Article CHATTERJI, BANKIM CHANDRA: "In 1872 he brought out his first
      social novel" 'social' amended from 'never'.

    Article CHEETA: "dropping from the car on the side remote from its
      prey, it approaches stealthily" 'prey' amended from 'sprey'.

    Article CHEMISTRY: "in which we may suppose the nitro-group to
      replace the a iodine atom" 'iodine' amended from 'hydrogen'.

    Article CHEMISTRY: "principles necessary to chemistry as a science"
      'science' amended from 'secience'.

    Article CHEMISTRY: "electromagnetic theory of light K = N²" 'N²'
      amended from N_2'.

    Article CHESS: "1. P-R8=Q, R-R7 ch;" 'R7' amended from 'Kt7'.

    Article CHESS: "5. QPxKt, R-R sq; 6. Kt-B8" 'B8' amended from 'B7'.



           ENCYCLOPÆDIA BRITANNICA

  A DICTIONARY OF ARTS, SCIENCES, LITERATURE
           AND GENERAL INFORMATION

              ELEVENTH EDITION


             VOLUME VI, SLICE I

            Châtelet to Chicago



ARTICLES IN THIS SLICE:


  CHÂTELET                          CHEQUE
  CHÂTELLERAULT                     CHER
  CHATHAM, WILLIAM PITT             CHERAT
  CHATHAM (New Brunswick, Canada)   CHERBOURG
  CHATHAM (Kent county Canada)      CHERBULIEZ, CHARLES VICTOR
  CHATHAM (Kent, England)           CHERCHEL
  CHATHAM ISLANDS                   CHERCHEN
  CHÂTILLON                         CHEREMISSES
  CHÂTILLON-SUR-SEINE               CHERIBON
  CHATSWORTH                        CHERKASY
  CHATTANOOGA                       CHERNIGOV (government of Russia)
  CHATTEL                           CHERNIGOV (town of Russia)
  CHATTERIS                         CHEROKEE
  CHATTERJI, BANKIM CHANDRA         CHEROOT
  CHATTERTON, THOMAS                CHERRAPUNJI
  CHATTI                            CHERRY
  CHAUCER, GEOFFREY                 CHERRYVALE
  CHAUDESAIGUES                     CHERRY VALLEY
  CHAUFFEUR                         CHERSIPHRON
  CHAULIEU, GUILLAUME AMFRYE DE     CHERSO
  CHAUMETTE, PIERRE GASPARD         CHERSONESE
  CHAUMONT-EN-BASSIGNY              CHERTSEY
  CHAUNCEY, ISAAC                   CHERUBIM
  CHAUNCY, CHARLES                  CHERUBINI, MARIA LUIGI
  CHAUNY                            CHÉRUEL, PIERRE ADOLPHE
  CHAUTAUQUA                        CHERUSCI
  CHAUVELIN, BERNARD FRANÇOIS       CHESELDEN, WILLIAM
  CHAUVIGNY                         CHESHAM
  CHAUVIN, ÉTIENNE                  CHESHIRE
  CHAUVINISM                        CHESHUNT
  CHAUX DE FONDS, LA                CHESIL BANK
  CHAVES                            CHESNELONG, PIERRE CHARLES
  CHAZELLES, JEAN MATHIEU DE        CHESNEY, CHARLES CORNWALLIS
  CHEADLE (Cheshire, England)       CHESNEY, FRANCIS RAWDON
  CHEADLE (Staffordshire, England)  CHESNEY, SIR GEORGE TOMKYNS
  CHEATING                          CHESS
  CHEBICHEV, PAFNUTIY LVOVICH       CHEST
  CHEBOYGAN                         CHESTER, EARLS OF
  CHECHENZES                        CHESTER (city of England)
  CHECKERS                          CHESTER (city of U.S.A.)
  CHEDDAR                           CHESTERFIELD, PHILIP DORMER STANHOPE
  CHEDUBA                           CHESTERFIELD
  CHEERING                          CHESTER-LE-STREET
  CHEESE                            CHESTERTON, GILBERT KEITH
  CHEESE CLOTH                      CHESTERTON (district of England)
  CHEETA                            CHESTNUT
  CHEFFONIER                        CHETTLE, HENRY
  CHEH-KIANG                        CHEVALIER, ALBERT
  CHEKE, SIR JOHN                   CHEVALIER, MICHEL
  CHELLIAN                          CHEVALIER, ULYSSE
  CHELMSFORD, FREDERIC THESIGER     CHEVAUX-DE-FRISE
  CHELMSFORD                        CHEVERUS, JEAN LOUIS DE
  CHELSEA (borough of London)       CHEVET
  CHELSEA (Massachusetts, U.S.A)    CHEVIOT HILLS
  CHELTENHAM                        CHEVREUL, MICHEL EUGÈNE
  CHELYABINSK                       CHEVRON
  CHELYS                            CHEVROTAIN
  CHEMICAL ACTION                   CHEYENNE (Indian Tribe)
  CHEMISTRY                         CHEYENNE (city of U.S.A.)
  CHEMNITZ (German theologian)      CHEYNE, THOMAS KELLY
  CHEMNITZ (town of Germany)        CHÉZY, ANTOINE LÉONARD DE
  CHEMOTAXIS                        CHHATARPUR
  CHENAB                            CHHATTISGARH
  CHÊNEDOLLÉ, CHARLES JULIEN DE     CHHINDWARA
  CHENERY, THOMAS                   CHIABRERA, GABRIELLO
  CHENG                             CHIANA
  CHÊN-HAI                          CHIAPAS
  CHÉNIER, ANDRÉ DE                 CHIAROSCURO
  CHÉNIER, MARIE-JOSEPH BLAISE DE   CHIAVARI
  CHENILLE                          CHIAVENNA
  CHENONCEAUX                       CHIBOUQUE
  CHENOPODIUM                       CHIC
  CHEOPS                            CHICACOLE
  CHEPSTOW                          CHICAGO



CHÂTELET (from Med. Lat. _castella_), the word, sometimes also written
_castillet_, used in France for a building designed for the defence of
an outwork or gate, sometimes of great strength or size, but
distinguished from the _château_, or castle proper, in being purely
defensive and not residential. In Paris, before the Revolution, this
word was applied both to a particular building and to the jurisdiction
of which it was the seat. This building, the original Châtelet, had been
first a castle defending the approach to the Cité. Tradition traced its
existence back to Roman times, and in the 18th century one of the rooms
in the great tower was still called the _chambre de César_. The
jurisdiction was that of the provostship (_prévôté_) and viscountship of
Paris, which was certainly of feudal origin, probably going back to the
counts of Paris.

It was not till the time of Saint Louis that, with the appointment of
Étienne Boileau, the provostship of Paris became a _prévôté en garde_,
i.e. a public office no longer put up to sale. When the _baillis_ (see
BAILIFF AND BAILIE) were created, the provost of Paris naturally
discharged the duties and functions of a _bailli_, in which capacity he
heard appeals from the seigniorial and inferior judges of the city and
its neighbourhood, keeping, however, his title of provost. When under
Henry II. certain _bailliages_ became presidial jurisdictions
(_présidiaux_), i.e. received to a certain extent the right of judging
without appeal, the Châtelet, the court of the provost of Paris, was
made a presidial court, but without losing its former name. Finally,
various tribunals peculiar to the city of Paris, i.e. courts exercising
jurisdictions outside the common law or corresponding to certain _cours
d'exception_ which existed in the provinces, were united with the
Châtelet, of which they became divisions (_chambres_). Thus the
lieutenant-general of police made it the seat of his jurisdiction, and
the provost of the Île de France, who had the same criminal jurisdiction
as the provosts of the marshals of France in other provinces, sat there
also. As to the _personnel_ of the Châtelet, it was originally the same
as in the _bailliages_, except that after the 14th century it had some
special officials, the auditors and the examiners of inquests. Like the
_baillis_, the provost had lieutenants who were deputies for him, and in
addition gradually acquired a considerable body of _ex officio_
councillors. This last staff, however, was not yet in existence at the
end of the 14th century, for it is not mentioned in the _Registre
criminel du Châtelet_ (1389-1392), published by the Société des
Bibliophiles Français. In 1674 the whole _personnel_ was doubled, at the
time when the new Châtelet was established side by side with the old,
the two being soon after amalgamated. On the eve of the Revolution it
comprised, beside the provost whose office had become practically
honorary, the _lieutenant civil_, who presided over the _chambre de
prévôté au parc civil_ or court of first instance; the _lieutenant
criminel_, who presided over the criminal court; two _lieutenants
particuliers_, who presided in turn over the _chambre du présidial_ or
court of appeal from the inferior jurisdictions; a _juge auditeur_;
sixty-four councillors (_conseillers_); the _procureur du roi_, four
_avocats du roi_, and eight _substituts_, i.e. deputies of the
_procureur_ (see PROCURATOR), beside a host of minor officials. The
history of the Châtelet under the Revolution may be briefly told: the
Constituent Assembly empowered it to try cases of _lèse-nation_, and it
was also before this court that was opened the inquiry following on the
events of the 5th and 6th of August 1789. It was suppressed by the law
of the 16th of August 1790, together with the other tribunals of the
_ancien régime_.        (J. P. E.)



CHÂTELLERAULT, a town of western France, capital of an arrondissement in
the department of Vienne, 19 m. N.N.E. of Poitiers on the Orleans
railway between that town and Tours. Pop. (1906) 15,214. Châtellerault
is situated on the right and eastern bank of the Vienne; it is connected
with the suburb of Châteauneuf on the opposite side of the river by a
stone bridge of the 16th and 17th centuries, guarded at the western
extremity by massive towers. The manufacture of cutlery is carried on on
a large scale in villages on the banks of the Clain, south of the town.
Of the other industrial establishments the most important is the
national small-arms factory, which was established in 1815 in
Châteauneuf, and employs from 1500 to 5500 men. Châtellerault (or
Châtelherault: _Castellum Airaldi_) derives its name from a fortress
built in the 10th century by Airaud, viscount of its territory. In 1515
it was made a duchy in favour of François de Bourbon, but it was not
long after this date that it became reunited to the crown. In 1548 it
was bestowed on James Hamilton, 2nd earl of Arran (see HAMILTON).



CHATHAM, WILLIAM PITT, 1st EARL OF (1708-1778), English statesman, was
born at Westminster on the 15th of November 1708. He was the younger son
of Robert Pitt of Boconnoc, Cornwall, and grandson of Thomas Pitt
(1653-1726), governor of Madras, who was known as "Diamond" Pitt, from
the fact of his having sold a diamond of extraordinary size to the
regent Orleans for something like £135,000. It was mainly by this
fortunate transaction that the governor was enabled to raise his family,
which was one of old standing, to a position of wealth and political
influence. The latter he acquired by purchasing the burgage tenures of
Old Sarum.

William Pitt was educated at Eton, and in January 1727 was entered as a
gentleman commoner at Trinity College, Oxford. There is evidence that he
was an extensively read, if not a minutely accurate classical scholar;
and it is interesting to know that Demosthenes was his favourite author,
and that he diligently cultivated the faculty of expression by the
practice of translation and re-translation. An hereditary gout, from
which he had suffered even during his school-days, compelled him to
leave the university without taking his degree, in order to travel
abroad. He spent some time in France and Italy; but the disease proved
intractable, and he continued subject to attacks of growing intensity at
frequent intervals till the close of his life. In 1727 his father had
died, and on his return home it was necessary for him, as the younger
son, to choose a profession. Having chosen the army, he obtained through
the interest of his friends a cornet's commission in the dragoons. But
his military career was destined to be short. His elder brother Thomas
having been returned at the general election of 1734 both for Oakhampton
and for Old Sarum, and having preferred to sit for the former, the
family borough fell to the younger brother by the sort of natural right
usually recognized in such cases. Accordingly, in February 1735, William
Pitt entered parliament as member for Old Sarum. Attaching himself at
once to the formidable band of discontented Whigs known as the Patriots,
whom Walpole's love of exclusive power had forced into opposition under
Pulteney, he became in a very short time one of its most prominent
members. His maiden speech was delivered in April 1736, in the debate on
the congratulatory address to the king on the marriage of the prince of
Wales. The occasion was one of compliment, and there is nothing striking
in the speech as reported; but it served to gain for him the attention
of the house when he presented himself, as he soon afterwards did, in
debates of a party character. So obnoxious did he become as a critic of
the government, that Walpole thought fit to punish him by procuring his
dismissal from the army. Some years later he had occasion vigorously to
denounce the system of cashiering officers for political differences,
but with characteristic loftiness of spirit he disdained to make any
reference to his own case. The loss of his commission was soon made up
to him. The heir to the throne, as was usually the case in the house of
Hanover, if not in reigning families generally, was the patron of the
opposition, and the ex-cornet became groom of the bed-chamber to the
prince of Wales. In this new position his hostility to the government
did not, as may be supposed, in any degree relax. He had all the natural
gifts an orator could desire--a commanding presence, a graceful though
somewhat theatrical bearing, an eye of piercing brightness, and a voice
of the utmost flexibility. His style, if occasionally somewhat turgid,
was elevated and passionate, and it always bore the impress of that
intensity of conviction which is the most powerful instrument a speaker
can have to sway the convictions of an audience. It was natural,
therefore, that in the series of stormy debates, protracted through
several years, that ended in the downfall of Walpole, his eloquence
should have been one of the strongest of the forces that combined to
bring about the final result. Specially effective, according to
contemporary testimony, were his speeches against the Hanoverian
subsidies, against the Spanish convention in 1739, and in favour of the
motion in 1742 for an investigation into the last ten years of Walpole's
administration. It must be borne in mind that the reports of these
speeches which have come down to us were made from hearsay, or at best
from recollection, and are necessarily therefore most imperfect. The
best-known specimen of Pitt's eloquence, his reply to the sneers of
Horatio Walpole at his youth and declamatory manner, which has found a
place in so many handbooks of elocution, is evidently, in form at least,
the work, not of Pitt, but of Dr Johnson, who furnished the report to
the _Gentleman's Magazine_. Probably Pitt did say something of the kind
attributed to him, though even this is by no means certain in view of
Johnson's repentant admission that he had often invented not merely the
form, but the substance of entire debates.

In 1742 Walpole was at last forced to succumb to the long-continued
attacks of opposition, and was succeeded as prime minister by the earl
of Wilmington, though the real power in the new government was divided
between Carteret and the Pelhams. Pitt's conduct on the change of
administration was open to grave censure. The relentless vindictiveness
with which he insisted on the prosecution of Walpole, and supported the
bill of indemnity to witnesses against the fallen minister, was in
itself not magnanimous; but it appears positively unworthy when it is
known that a short time before Pitt had offered, on certain conditions,
to use all his influence in the other direction. Possibly he was
embittered at the time by the fact that, owing to the strong personal
dislike of the king, caused chiefly by the contemptuous tone in which he
had spoken of Hanover, he did not by obtaining a place in the new
ministry reap the fruits of the victory to which he had so largely
contributed. The so-called "broad-bottom" administration formed by the
Pelhams in 1744, after the dismissal of Carteret, though it included
several of those with whom he had been accustomed to act, did not at
first include Pitt himself even in a subordinate office. Before the
obstacle to his admission was overcome, he had received a remarkable
accession to his private fortune. The eccentric duchess of Marlborough,
dying in 1744, at the age of ninety, left him a legacy of £10,000 as an
"acknowledgment of the noble defence he had made for the support of the
laws of England and to prevent the ruin of his country." As her hatred
was known to be at least as strong as her love, the legacy was probably
as much a mark of her detestation of Walpole as of her admiration of
Pitt. It may be mentioned here, though it does not come in chronological
order, that Pitt was a second time the object of a form of
acknowledgment of public virtue which few statesmen have had the fortune
to receive even once. About twenty years after the Marlborough legacy,
Sir William Pynsent, a Somersetshire baronet to whom he was personally
quite unknown, left him his entire estate, worth about three thousand a
year, in testimony of approval of his political career.

It was with no very good grace that the king at length consented to give
Pitt a place in the government, although the latter did all he could to
ingratiate himself at court, by changing his tone on the questions on
which he had made himself offensive. To force the matter, the Pelhams
had to resign expressly on the question whether he should be admitted or
not, and it was only after all other arrangements had proved
impracticable, that they were reinstated with the obnoxious politician
as vice-treasurer of Ireland. This was in February 1746. In May of the
same year he was promoted to the more important and lucrative office of
paymaster-general, which gave him a place in the privy council, though
not in the cabinet. Here he had an opportunity of displaying his public
spirit and integrity in a way that deeply impressed both the king and
the country. It had been the usual practice of previous paymasters to
appropriate to themselves the interest of all money lying in their hands
by way of advance, and also to accept a commission of 1/2% on all
foreign subsidies. Although there was no strong public sentiment against
the practice, Pitt altogether refused to profit by it. All advances were
lodged by him in the Bank of England until required, and all subsidies
were paid over without deduction, even though it was pressed upon him,
so that he did not draw a shilling from his office beyond the salary
legally attaching to it. Conduct like this, though obviously
disinterested, did not go without immediate and ample reward, in the
public confidence which it created, and which formed the mainspring of
Pitt's power as a statesman.

The administration formed in 1746 lasted without material change till
1754. It would appear from his published correspondence that Pitt had a
greater influence in shaping its policy than his comparatively
subordinate position would in itself have entitled him to. His conduct
in supporting measures, such as the Spanish treaty and the continental
subsidies, which he had violently denounced when in opposition, had been
much criticized; but within certain limits, not indeed very well
defined, inconsistency has never been counted a vice in an English
statesman. The times change, and he is not blamed for changing with the
times. Pitt in office, looking back on the commencement of his public
life, might have used the plea "A good deal has happened since then," at
least as justly as some others have done. Allowance must always be made
for the restraints and responsibilities of office. In Pitt's case, too,
it is to be borne in mind that the opposition with which he had acted
gradually dwindled away, and that it ceased to have any organized
existence after the death of the prince of Wales in 1751. Then in regard
to the important question with Spain as to the right of search, Pitt
has disarmed criticism by acknowledging that the course he followed
during Wapole's administration was indefensible. All due weight being
given to these various considerations, it must be admitted,
nevertheless, that Pitt did overstep the limits within which
inconsistency is usually regarded as venial. His one great object was
first to gain office, and then to make his tenure of office secure by
conciliating the favour of the king. The entire revolution which much of
his policy underwent in order to effect this object bears too close a
resemblance to the sudden and inexplicable changes of front habitual to
placemen of the Tadpole stamp to be altogether pleasant to contemplate
in a politician of pure aims and lofty ambition. Humiliating is not too
strong a term to apply to a letter in which he expresses his desire to
"efface the past by every action of his life," in order that he may
stand well with the king.

In 1754 Henry Pelham died, and was succeeded at the head of affairs by
his brother, the duke of Newcastle. To Pitt the change brought no
advancement, and he had thus an opportunity of testing the truth of the
description of his chief given by Sir Robert Walpole, "His name is
treason." But there was for a time no open breach. Pitt continued at his
post; and at the general election which took place during the year he
even accepted a nomination for the duke's pocket borough of Aldborough.
He had sat for Seaford since 1747. When parliament met, however, he was
not long in showing the state of his feelings. Ignoring Sir Thomas
Robinson, the political nobody to whom Newcastle had entrusted the
management of the Commons, he made frequent and vehement attacks on
Newcastle himself, though still continuing to serve under him. In this
strange state matters continued for about a year. At length, just after
the meeting of parliament in November 1751, Pitt was dismissed from
office, having on the debate on the address spoken at great length
against a new system of continental subsidies, proposed by the
government of which he was a member. Fox, who had just before been
appointed secretary of state, retained his place, and though the two men
continued to be of the same party, and afterwards served again in the
same government, there was henceforward a rivalry between them, which
makes the celebrated opposition of their illustrious sons seem like an
inherited quarrel.

Another year had scarcely passed when Pitt was again in power. The
inherent weakness of the government, the vigour and eloquence of his
opposition, and a series of military disasters abroad combined to rouse
a public feeling of indignation which could not be withstood, and in
December 1756 Pitt, who now sat for Okehampton, became secretary of
state, and leader of the Commons under the premiership of the duke of
Devonshire. He had made it a condition of his joining any administration
that Newcastle should be excluded from it, thus showing a resentment
which, though natural enough, proved fatal to the lengthened existence
of his government. With the king unfriendly, and Newcastle, whose
corrupt influence was still dominant in the Commons, estranged, it was
impossible to carry on a government by the aid of public opinion alone,
however emphatically that might have declared itself on his side. In
April 1757, accordingly, he found himself again dismissed from office on
account of his opposition to the king's favourite continental policy.
But the power that was insufficient to keep him in office was strong
enough to make any arrangement that excluded him impracticable. The
public voice spoke in a way that was not to be mistaken. Probably no
English minister ever received in so short a time so many proofs of the
confidence and admiration of the public, the capital and all the chief
towns voting him addresses and the freedom of their corporations. From
the political deadlock that ensued relief could only be had by an
arrangement between Newcastle and Pitt. After some weeks' negotiation,
in the course of which the firmness and moderation of "the Great
Commoner," as he had come to be called, contrasted favourably with the
characteristic tortuosities of the crafty peer, matters were settled on
such a basis that, while Newcastle was the nominal, Pitt was the virtual
head of the government. On his acceptance of office he was chosen member
for Bath.

This celebrated administration was formed in June 1757, and continued
in power till 1761. During the four years of its existence it has been
usual to say that the biography of Pitt is the history of England, so
thoroughly was he identified with the great events which make this
period, in so far as the external relations of the country are
concerned, one of the most glorious in her annals. A detailed account of
these events belongs to history; all that is needed in a biography is to
point out the extent to which Pitt's personal influence may really be
traced in them. It is scarcely too much to say that, in the general
opinion of his contemporaries, the whole glory of these years was due to
his single genius; his alone was the mind that planned, and his the
spirit that animated the brilliant achievements of the British arms in
all the four quarters of the globe. Posterity, indeed, has been able to
recognize more fully the independent genius of those who carried out his
purposes. The heroism of Wolfe would have been irrepressible, Clive
would have proved himself "a heaven-born general," and Frederick the
Great would have written his name in history as one of the most skilful
strategists the world has known, whoever had held the seals of office in
England. But Pitt's relation to all three was such as to entitle him to
a large share in the credit of their deeds. It was his discernment that
selected Wolfe to lead the attack on Quebec, and gave him the
opportunity of dying a victor on the heights of Abraham. He had
personally less to do with the successes in India than with the other
great enterprises that shed an undying lustre on his administration; but
his generous praise in parliament stimulated the genius of Clive, and
the forces that acted at the close of the struggle were animated by his
indomitable spirit. Pitt, the first real Imperialist in modern English
history, was the directing mind in the expansion of his country, and
with him the beginning of empire is rightly associated. The Seven Years'
War might well, moreover, have been another Thirty Years' War if Pitt
had not furnished Frederick with an annual subsidy of £700,000, and in
addition relieved him of the task of defending western Germany against
France.

Contemporary opinion was, of course, incompetent to estimate the
permanent results gained for the country by the brilliant foreign policy
of Pitt. It has long been generally agreed that by several of his most
costly expeditions nothing was really won but glory. It has even been
said that the only permanent acquisition that England owed directly to
him was her Canadian dominion; and, strictly speaking, this is true, it
being admitted that the campaign by which the Indian empire was
virtually won was not planned by him, though brought to a successful
issue during his ministry. But material aggrandizement, though the only
tangible, is not the only real or lasting effect of a war policy. More
may be gained by crushing a formidable rival than by conquering a
province. The loss of her Canadian possessions was only one of a series
of disasters suffered by France, which radically affected the future of
Europe and the world. Deprived of her most valuable colonies both in the
East and in the West, and thoroughly defeated on the continent, her
humiliation was the beginning of a new epoch in history. The victorious
policy of Pitt destroyed the military prestige which repeated experience
has shown to be in France as in no other country the very life of
monarchy, and thus was not the least considerable of the many influences
that slowly brought about the French Revolution. It effectually deprived
her of the lead in the councils of Europe which she had hitherto
arrogated to herself, and so affected the whole course of continental
politics. It is such far-reaching results as these, and not the mere
acquisition of a single colony, however valuable, that constitute Pitt's
claim to be considered as on the whole the most powerful minister that
ever guided the foreign policy of England.

The first and most important of a series of changes which ultimately led
to the dissolution of the ministry was the death of George II. on the
25th of October 1760, and the accession of his grandson, George III. The
new king had, as was natural, new counsellors of his own, the chief of
whom, Lord Bute, was at once admitted to the cabinet as a secretary of
state. Between Bute and Pitt there speedily arose an occasion of serious
difference. The existence of the so-called family compact by which the
Bourbons of France and Spain bound themselves in an offensive alliance
against England having been brought to light, Pitt urged that it should
be met by an immediate declaration of war with Spain. To this course
Bute would not consent, and as his refusal was endorsed by all his
colleagues save Temple, Pitt had no choice but to leave a cabinet in
which his advice on a vital question had been rejected. On his
resignation, which took place in October 1761, the king urged him to
accept some signal mark of royal favour in the form most agreeable to
himself. Accordingly he obtained a pension of £3000 a year for three
lives, and his wife, Lady Hester Grenville, whom he had married in 1754,
was created Baroness Chatham in her own right. In connexion with the
latter gracefully bestowed honour it may be mentioned that Pitt's
domestic life was a singularly happy one.

Pitt's spirit was too lofty to admit of his entering on any merely
factious opposition to the government he had quitted. On the contrary,
his conduct after his retirement was distinguished by a moderation and
disinterestedness which, as Burke has remarked, "set a seal upon his
character." The war with Spain, in which he had urged the cabinet to
take the initiative, proved inevitable; but he scorned to use the
occasion for "altercation and recrimination," and spoke in support of
the government measures for carrying on the war. To the preliminaries of
the peace concluded in February 1763 he offered an indignant resistance,
considering the terms quite inadequate to the successes that had been
gained by the country. When the treaty was discussed in parliament in
December of the preceding year, though suffering from a severe attack of
gout, he was carried down to the House, and in a speech of three hours'
duration, interrupted more than once by paroxysms of pain, he strongly
protested against its various conditions. The physical cause which
rendered this effort so painful probably accounts for the infrequency of
his appearances in parliament, as well as for much that is otherwise
inexplicable in his subsequent conduct. In 1763 he spoke against the
obnoxious tax on cider, imposed by his brother-in-law, George Grenville,
and his opposition, though unsuccessful in the House, helped to keep
alive his popularity with the country, which cordially hated the excise
and all connected with it. When next year the question of general
warrants was raised in connexion with the case of Wilkes, Pitt
vigorously maintained their illegality, thus defending at once the
privileges of Parliament and the freedom of the press. During 1765 he
seems to have been totally incapacitated for public business. In the
following year he supported with great power the proposal of the
Rockingham administration for the repeal of the American Stamp Act,
arguing that it was unconstitutional to impose taxes upon the colonies.
He thus endorsed the contention of the colonists on the ground of
principle, while the majority of those who acted with him contented
themselves with resisting the disastrous taxation scheme on the ground
of expediency. The Repeal Act, indeed, was only passed _pari passu_ with
another censuring the American assemblies, and declaring the authority
of the British parliament over the colonies "in all cases whatsoever";
so that the House of Commons repudiated in the most formal manner the
principle Pitt laid down. His language in approval of the resistance of
the colonists was unusually bold, and perhaps no one but himself could
have employed it with impunity at a time when the freedom of debate was
only imperfectly conceded.

Pitt had not been long out of office when he was solicited to return to
it, and the solicitations were more than once renewed. Unsuccessful
overtures were made to him in 1763, and twice in 1765, in May and
June--the negotiator in May being the king's uncle, the duke of
Cumberland, who went down in person to Hayes, Pitt's seat in Kent. It is
known that he had the opportunity of joining the marquis of Rockingham's
short-lived administration at any time on his own terms, and his conduct
in declining an arrangement with that minister has been more generally
condemned than any other step in his public life. In July 1766
Rockingham was dismissed, and Pitt was entrusted by the king with the
task of forming a government entirely on his own conditions. The result
was a cabinet, strong much beyond the average in its individual members,
but weak to powerlessness in the diversity of its composition. Burke, in
a memorable passage of a memorable speech, has described this "chequered
and speckled" administration with great humour, speaking of it as
"indeed a very curious show, but utterly unsafe to touch and unsure to
stand on." Pitt chose for himself the office of lord privy seal, which
necessitated his removal to the House of Lords; and in August he became
earl of Chatham and Viscount Pitt.

By the acceptance of a peerage the great commoner lost at least as much
and as suddenly in popularity as he gained in dignity. One significant
indication of this may be mentioned. In view of his probable accession
to power, preparations were made in the city of London for a banquet and
a general illumination to celebrate the event. But the celebration was
at once countermanded when it was known that he had become earl of
Chatham. The instantaneous revulsion of public feeling was somewhat
unreasonable, for Pitt's health seems now to have been beyond doubt so
shattered by his hereditary malady, that he was already in old age
though only fifty-eight. It was natural, therefore, that he should
choose a sinecure office, and the ease of the Lords. But a popular idol
nearly always suffers by removal from immediate contact with the popular
sympathy, be the motives for removal what they may.

One of the earliest acts of the new ministry was to lay an embargo upon
corn, which was thought necessary in order to prevent a dearth resulting
from the unprecedentedly bad harvest of 1766. The measure was strongly
opposed, and Lord Chatham delivered his first speech in the House of
Lords in support of it. It proved to be almost the only measure
introduced by his government in which he personally interested himself.
His attention had been directed to the growing importance of the affairs
of India, and there is evidence in his correspondence that he was
meditating a comprehensive scheme for transferring much of the power of
the company to the crown, when he was withdrawn from public business in
a manner that has always been regarded as somewhat mysterious. It may be
questioned, indeed, whether even had his powers been unimpaired he could
have carried out any decided policy on any question with a cabinet
representing interests so various and conflicting; but, as it happened,
he was incapacitated physically and mentally during nearly the Whole
period of his tenure of office. He scarcely ever saw any of his
colleagues though they repeatedly and urgently pressed for interviews
with him, and even an offer from the king to visit him in person was
declined, though in the language of profound and almost abject respect
which always marked his communications with the court. It has been
insinuated both by contemporary and by later critics that being
disappointed at his loss of popularity, and convinced of the
impossibility of co-operating with his colleagues, he exaggerated his
malady as a pretext for the inaction that was forced upon him by
circumstances. But there is no sufficient reason to doubt that he was
really, as his friends represented, in a state that utterly unfitted him
for business. He seems to have been freed for a time from the pangs of
gout only to be afflicted with a species of mental alienation bordering
on insanity. This is the most satisfactory, as it is the most obvious,
explanation of his utter indifference in presence of one of the most
momentous problems that ever pressed for solution on an English
statesman. Those who are able to read the history in the light of what
occurred later may perhaps be convinced that no policy whatever
initiated, after 1766 could have prevented or even materially delayed
the declaration of American independence; but to the politicians of that
time the coming event had not yet cast so dark a shadow before as to
paralyse all action, and if any man could have allayed the growing
discontent of the colonists and prevented the ultimate dismemberment of
the empire, it would have been Lord Chatham. The fact that he not only
did nothing to remove existing difficulties, but remained passive while
his colleagues took the fatal step which led directly to separation, is
in itself clear proof of his entire incapacity. The imposition of the
import duty on tea and other commodities was the project of Charles
Townshend, and was carried into effect in 1767 without consultation with
Lord Chatham, if not in opposition to his wishes. It is probably the
most singular thing in connexion with this singular administration, that
its most pregnant measure should thus have been one directly opposed to
the well-known principles of its head.

For many months things remained in the curious position that he who was
understood to be the head of the cabinet had as little share in the
government of the country as an unenfranchised peasant. As the chief
could not or would not lead, the subordinates naturally chose their own
paths and not his. The lines of Chatham's policy were abandoned in other
cases besides the imposition of the import duty; his opponents were
taken into confidence; and friends, such' as Amherst and Shelburne, were
dismissed from their posts. When at length in October 1768 he tendered
his resignation on the ground of shattered health, he did not fail to
mention the dismissal of Amherst and Shelburne as a personal grievance.

Soon after his resignation a renewed attack of gout freed Chatham from
the mental disease under which he had so long suffered. He had been
nearly two years and a half in seclusion when, in July 1769, he again
appeared in public at a royal levee. It was not, however, until 1770
that he resumed his seat in the House of Lords. He had now almost no
personal following, mainly owing to the grave mistake he had made in not
forming an alliance with the Rockingham party. But his eloquence was as
powerful as ever, and all its power was directed against the government
policy in the contest with America, which had become the question of
all-absorbing interest. His last appearance in the House of Lords was on
the 7th of April 1778, on the occasion of the duke of Richmond's motion
for an address praying the king to conclude peace with America on any
terms. In view of the hostile demonstrations of France the various
parties had come generally to see the necessity of such a measure. But
Chatham could not brook the thought of a step which implied submission
to the "natural enemy" whom it had been the main object of his life to
humble, and he declaimed for a considerable time, though with sadly
diminished vigour, against the motion. After the duke of Richmond had
replied, he rose again excitedly as if to speak, pressed his hand upon
his breast, and fell down in a fit. He was removed to his seat at Hayes,
where he died on the 11th of May. With graceful unanimity all parties
combined to show their sense of the national loss. The Commons presented
an address to the king praying that the deceased statesman might be
buried with the honours of a public funeral, and voted a sum for a
public monument which was erected over his grave in Westminster Abbey.
Soon after the funeral a bill was passed bestowing a pension of £4000 a
year on his successors in the earldom. He had a family of three sons and
two daughters, of whom the second son, William, was destined to add
fresh lustre to a name which is one of the greatest in the history of
England.

Dr Johnson is reported to have said that "Walpole was a minister given
by the king to the people, but Pitt was a minister given by the people
to the king," and the remark correctly indicates Chatham's distinctive
place among English statesmen. He was the first minister whose main
strength lay in the support of the nation at large as distinct from its
representatives in the Commons, where his personal following was always
small. He was the first to discern that public opinion, though generally
slow to form and slow to act, is in the end the paramount power in the
state; and he was the first to use it not in an emergency merely, but
throughout a whole political career. He marks the commencement of that
vast change in the movement of English politics by which it has come
about that the sentiment of the great mass of the people now tells
effectively on the action of the government from day to day,--almost
from hour to hour. He was well fitted to secure the sympathy and
admiration of his countrymen, for his virtues and his failings were
alike English. He was often inconsistent, he was generally intractable
and overbearing, and he was always pompous and affected to a degree
which, Macaulay has remarked, seems scarcely compatible with true
greatness. Of the last quality evidence is furnished in the stilted
style of his letters, and in the fact recorded by Seward that he never
permitted his under-secretaries to sit in his presence. Burke speaks of
"some significant, pompous, creeping, explanatory, ambiguous matter, in
the true Chathamic style." But these defects were known only to the
inner circle of his associates. To the outside public he was endeared as
a statesman who could do or suffer "nothing base," and who had the rare
power of transfusing his own indomitable energy and courage into all who
served under him. "A spirited foreign policy" has always been popular in
England, and Pitt was the most popular of English ministers, because he
was the most successful exponent of such a policy. In domestic affairs
his influence was small and almost entirely indirect. He himself
confessed his unfitness for dealing with questions of finance. The
commercial prosperity that was produced by his war policy was in a great
part delusive, as prosperity so produced must always be, though it had
permanent effects of the highest moment in the rise of such centres of
industry as Glasgow. This, however, was a remote result which he could
have neither intended nor foreseen.

  The correspondence of Lord Chatham, in four volumes, was published in
  1838-1840; and a volume of his letters to Lord Camelford in 1804. The
  Rev. Francis Thackeray's _History of the Rt. Hon. William Pitt, Earl
  of Chatham_ (2 vols., 1827), is a ponderous and shapeless work.
  Frederic Harrison's _Chatham_, in the "Twelve English Statesmen"
  series (1905), though skilfully executed, takes a rather academic and
  modern Liberal view. A German work, _William Pitt, Graf von Chatham_,
  by Albert von Ruville (3 vols., 1905; English trans. 1907), is the
  best and most thorough account of Chatham, his period, and his policy,
  which has appeared. See also the separate article on William Pitt, and
  the authorities referred to, especially the Rev. William Hunt's
  appendix i. to his vol. x. of _The Political History of England_
  (1905).



CHATHAM, also called MIRAMICHI, an incorporated town and port of entry
in Northumberland county, New Brunswick, Canada, on the Miramichi river,
24 m. from its mouth and 10 m. by rail from Chatham junction on the
Intercolonial railway. Pop. (1901) 5000. The town contains the Roman
Catholic pro-cathedral, many large saw-mills, pulp-mills, and several
establishments for curing and exporting fish. The lumber trade, the
fisheries, and the manufacture of pulp are the chief industries.



CHATHAM, a city and port of entry of Ontario, Canada, and the capital of
Kent county, situated 64 m. S.W. of London, and 11 m. N. of Lake Erie,
on the Thames river and the Grand Trunk, Canadian Pacific and Lake Erie
& Detroit River railways. Pop. (1901) 9068. It has steamboat connexion
with Detroit and the cities on Lakes Huron and Erie. It is situated in a
rich agricultural and fruit-growing district, and carries on a large
export trade. It contains a large wagon factory, planing and flour
mills, manufactories of fanning mills, binder-twine, woven wire goods,
engines, windmills, &c.



CHATHAM, a port and municipal and parliamentary borough of Kent,
England, on the right bank of the Medway, 34 m. E.S.E. of London by the
South-Eastern & Chatham railway. Pop. (1891) 31,657; (1901) 37,057.
Though a distinct borough it is united on the west with Rochester and on
the east with Gillingham, so that the three boroughs form, in
appearance, a single town with a population which in 1901 exceeded
110,000. With the exception of the dockyards and fortifications there
are few objects of interest. St Mary's church was opened in 1903, but
occupies a site which bore a church in Saxon times, though the previous
building dated only from 1786. A brass commemorates Stephen Borough (d.
1584), discoverer of the northern passage to Archangel in Russia (1553).
St Bartholomew's chapel, originally attached to the hospital for lepers
(one of the first in England), founded by Gundulph, bishop of Rochester,
in 1070, is in part Norman. The funds for the maintenance of the
hospital were appropriated by decision of the court of chancery to the
hospital of St Bartholomew erected in 1863 within the boundaries of
Rochester. The almshouse established in 1592 by Sir John Hawkins for
decayed seamen and shipwrights is still extant, the building having been
re-erected in the 19th century; but the fund called the Chatham Chest,
originated by Hawkins and Drake in 1588, was incorporated with
Greenwich Hospital in 1802. In front of the Royal Engineers' Institute
is a statue (1890) of General Gordon, and near the railway station
another (1888) to Thomas Waghorn, promoter of the overland route to
India. In 1905 King Edward VII. unveiled a fine memorial arch
commemorating Royal Engineers who fell in the South African War. It
stands in the parade ground of the Brompton barracks, facing the Crimean
arch. There are numerous brickyards, lime-kilns and flour-mills in the
district neighbouring to Chatham; and the town carries on a large retail
trade, in great measure owing to the presence of the garrison. The
fortifications are among the most elaborate in the kingdom. The
so-called Chatham Lines enclose New Brompton, a part of the borough of
Gillingham. They were begun in 1758 and completed in 1807, but have been
completely modernized. They are strengthened by several detached forts
and redoubts. Fort Pitt, which rises above the town to the west, was
built in 1779, and is used as a general military hospital. It was
regarded as the principal establishment of the kind in the country till
the foundation of Netley in Hampshire. The lines include the Chatham,
the Royal Marine, the Brompton, the Hut, St Mary's and naval barracks;
the garrison hospital, Melville hospital for sailors and marines, the
arsenal, gymnasium, various military schools, convict prison, and
finally the extensive dockyard system for which the town is famous. This
dockyard covers an area of 516 acres, and has a river frontage of over 3
m. It was brought into its present state by the extensive works begun
about 1867. Before that time there was no basin or wet-dock, though the
river Medway to some extent answered the same purpose, but a portion of
the adjoining salt-marshes was then taken in, and three basins have been
constructed, communicating with each other by means of large locks, so
that ships can pass from the bend of the Medway at Gillingham to that at
Upnor. Four graving docks were also formed, opening out of the first
(Upnor) basin. Subsequent improvements included dredging operations in
the Medway to improve the approach, and the provision of extra dry-dock
accommodation under the Naval Works Acts.

The parliamentary borough returns one member. The town was incorporated
in 1890, and is governed by a mayor, six aldermen and eighteen
councillors. Area, 4355 acres. The borough includes the suburb (an
ecclesiastical parish) of Luton, in which are the waterworks of Chatham
and the adjoining towns.

Chatham (_Ceteham, Chetham_) belonged at the time of the Domesday Survey
to Odo, bishop of Bayeux. During the middle ages it formed a suburb of
Rochester, but Henry VIII. in founding a regular navy began to establish
dockyards, and the harbour formed by the deep channel of the Medway was
utilized by Elizabeth, who built a dockyard and established an arsenal
here. The dockyard was altered and improved by Charles I. and Charles
II., and became the chief naval station of England. In 1708 an act was
passed for extending the fortifications of Chatham. During the
excavations on Chatham Hill after 1758 a number of tumuli containing
human remains, pottery, coins, &c., suggestive of an ancient settlement,
were found. Chatham was constituted a parliamentary borough by the
Reform Bill of 1832. In the time of Edward III. the lord of the manor
had two fairs, one on the 24th of August and the other on the 8th of
September. A market to be held on Tuesday, and a fair on the 4th, 5th
and 6th of May, were granted by Charles II. in 1679, and another
provision market on Saturday by James II. in 1688. In 1738 fairs were
held on the 4th of May and the 8th of September, and a market every
Saturday.



CHATHAM ISLANDS, a small group in the Pacific Ocean, forming part of New
Zealand, 536 m. due E. of Lyttelton in the South Island, about 44° S.,
177° W. It consists of three islands, a large one called Whairikauri, or
Chatham Island, a smaller one, Rangihaute, or Pitt Island, and a third,
Rangatira, or South-east Island. There are also several small rocky
islets. Whairikauri, whose highest point reaches about 1000 ft., is
remarkable for the number of lakes and tarns it contains, and for the
extensive bogs which cover the surface of nearly the whole of the
uplands. It is of very irregular form, about 38 m. in length and 25 m.
in extreme breadth, with an area of 321 sq. m.--a little larger than
Middlesex. The geological formation is principally of volcanic rocks,
with schists and tertiary limestone; and an early physical connexion of
the islands with New Zealand is indicated by their geology and biology.
The climate is colder than that of New Zealand. In the centre of
Whairikauri is a large brackish lake called Tewanga, which at the
southern end is separated from the sea by a sandbank only 150 yds. wide,
which it occasionally bursts through. The southern part of the island
has an undulating surface, and is covered either with an open forest or
with high ferns. In general the soil is extremely fertile, and where it
is naturally drained a rich vegetation of fern and flax occurs. On the
north-west are several conical hills of basalt, which are surrounded by
oases of fertile soil. On the south-western side is Petre Bay, on which,
at the mouth of the river Mantagu, is Waitangi, the principal
settlement.

The islands were discovered in 1791 by Lieutenant W.R. Broughton
(1762-1821), who gave them the name of Chatham from the brig which he
commanded. He described the natives as a bright, pleasure-loving people,
dressed in sealskins or mats, and calling themselves Morioris or
Maiorioris. In 1831 they were conquered by 800 Maoris who were landed
from a European vessel. They were almost exterminated, and an epidemic
of influenza in 1839 killed half of those left; ten years later there
were only 90 survivors out of a total population of 1200. They
subsequently decreased still further. Their language was allied to that
of the Maoris of New Zealand, but they differed somewhat from them in
physique, and they were probably a cross between an immigrating
Polynesian group and a lower indigenous Melanesian stock. The population
of the islands includes about 200 whites of various races and the same
number of natives (chiefly Maoris). Cattle and sheep are bred, and a
trade is carried on in them with the whalers which visit these seas. The
chief export from the group is wool, grown upon runs farmed both by
Europeans and Morioris. There is also a small export by the natives of
the flesh of young albatrosses and other sea-birds, boiled down and
cured, for the Maoris of New Zealand, by whom it is reckoned a delicacy.
The imports consist of the usual commodities required by a population
where little of the land is actually cultivated.

There are no indigenous mammals; the reptiles belong to New Zealand
species. The birds--the largest factor in the fauna--have become very
greatly reduced through the introduction of cats, dogs and pigs, as well
as by the constant persecution of every sort of animal by the natives.
The larger bell-bird (_Anthornis melanocephala_) has become quite
scarce; the magnificent fruit-pigeon (_Carpophaga chathamensis_), and
the two endemic rails (_Nesolimnas dieffenbachii_ and _Cabalus
modestus_), the one of which was confined to Whairikauri and the other
to Mangare Island, are extinct. Several fossil or subfossil avian forms,
very interesting from the point of view of geographical distribution,
have been discovered by Dr H.O. Forbes, namely, a true species of raven
(_Palaeocorax moriorum_), a remarkable rail (_Diaphorapteryx_), closely
related to the extinct _Aphanapteryx_ of Mauritius, and a large coot
(_Palaeolimnas chathamensis_). There have also been discovered the
remains of a species of swan belonging to the South American genus
_Chenopis_, and of the tuatara (_Hatteria_) lizard, the unique species
of an ancient family now surviving only in New Zealand. The swan is
identical with an extinct species found in caves and kitchen-middens in
New Zealand, which was contemporaneous with the prehistoric Maoris and
was largely used by them for food. One of the finest of the endemic
flowering plants of the group is the boraginaceous "Chatham Island lily"
(_Myositidium nobile_), a gigantic forget-me-not, which grows on the
shingly shore in a few places only, and always just on the high-water
mark, where it is daily deluged by the waves; while dracophyllums,
leucopogons and arborescent ragworts are characteristic forms in the
vegetation.

  See Bruno Weiss, _Fünfzig Jahre auf Chatham Island_ (Berlin, 1900);
  H.O. Forbes, "The Chatham Islands and their Story," _Fortnightly
  Review_ (1893), vol. liii. p. 669, "The Chatham Islands, their
  relation to a former Southern Continent," _Supplementary_ _Papers_,
  R.G.S., vol. iii. (1893); J.H. Scott, "The Osteology of the Maori and
  the Moriori," _Trans. New Zealand Institute_, vol. xxvi. (1893); C.W.
  Andrews, "The Extinct Birds of the Chatham Islands," _Novitates
  Zoologicae_, vol. ii. p. 73 (1896).



CHÂTILLON, the name of a French family whose history has furnished
material for a large volume in folio by A. du Chesne, a learned
Frenchman, published in 1621. But in spite of its merits this book
presents a certain number of inaccurate statements, some of which it is
important to notice. If, for instance, it be true that the Châtillons
came from Châtillon-sur-Marne (Marne, arrondissement of Reims), it is
now certain that, since the 11th century, this castle belonged to the
count of Champagne, and that the head of the house of Châtillon was
merely tenant in that place. One of them, however, Gaucher of Châtillon,
lord of Crécy and afterwards constable of France, became in 1290 lord of
Châtillon-sur-Marne by exchange, but since 1303 a new agreement allotted
to him the countship of Porcien, while Châtillon reverted to the domain
of the counts of Champagne. It may be well to mention also that, in
consequence of a resemblance of their armorial bearings, du Chesne
considered wrongly that the lords of Bazoches and those of
Château-Porcien of the 12th and 13th centuries drew their descent from
the house of Châtillon.

The most important branches of the house of Châtillon were those of (1)
St Pol, beginning with Gaucher III. of Châtillon, who became count of St
Pol in right of his wife Isabella in 1205, the last male of the line
being Guy V. (d. 1360); (2) Blois, founded by the marriage of Hugh of
Châtillon-St Pol (d. 1248) with Mary, daughter of Margaret of Blois (d.
1230),--this branch became extinct with the death of Guy II. in 1397;
(3) Porcien, from 1303 to 1400, when Count John sold the countship to
Louis, duke of Orleans; (4) Penthièvre, by the marriage of Charles of
Blois (d. 1364) with Jeanne (d. 1384), heiress of Guy, count of
Penthièvre (d. 1331), the male line becoming extinct in 1457.

  See A. du Chesne, _Histoire généalogique de la maison de
  Chastillon-sur-Marne_ (1621); Anselme, _Histoire généalogique de la
  maison royale de France_, vi. 91-124 (1730).      (A. Lo.)



CHÂTILLON-SUR-SEINE, a town of eastern France, capital of an
arrondissement in the department of Côte-d'Or, on the Eastern and
Paris-Lyon railways, 67 m. N.N.W. of Dijon, between that city and
Troyes. Pop. (1906) 4430. It is situated on both banks of the upper
Seine, which is swelled at its entrance to the town by the Douix, one of
the most abundant springs in France. Châtillon is constructed on ample
lines and rendered attractive by beautiful promenades. Some ruins on an
eminence above it mark the site of a château of the dukes of Burgundy.
Near by stands the church of St Vorle of the l0th century, but with many
additions of later date; it contains a sculptured Holy Sepulchre of the
16th century and a number of frescoes. In a fine park stands a modern
château built by Marshal Marmont, duke of Ragusa, born at Châtillon in
1774. It was burnt in 1871, and subsequently rebuilt. The town preserves
several interesting old houses. Châtillon has a sub-prefecture,
tribunals of first instance and of commerce, a school of agriculture and
a communal college. Among its industries are brewing, iron-founding and
the manufacture of mineral and other blacks. It has trade in wood,
charcoal, lithographic and other stone. Châtillon anciently consisted of
two parts, Chaumont, belonging to the duchy of Burgundy, and Bourg,
ruled by the bishop of Langres; it did not coalesce into one town till
the end of the 16th century. It was taken by the English in 1360 and by
Louis XI. in 1475, during his struggle with Charles the Bold. Châtillon
was one of the first cities to adhere to the League, but suffered
severely from the oppression of its garrisons and governors, and in 1595
made voluntary submission to Henry IV. In modern times it is associated
with the abortive conference of 1814 between the representatives of
Napoleon and the Allies.



CHATSWORTH, a village of Derbyshire, England, containing a seat
belonging to the duke of Devonshire, one of the most splendid private
residences in England. Chatsworth House is situated close to the left
bank of the river Derwent, 2¾ m. from Bakewell. It is Ionic in style,
built foursquare, and enclosing a large open courtyard, with a fountain
in the centre. In front, a beautiful stretch of lawn slopes gradually
down to the riverside, and a bridge, from which may best be seen the
grand façade of the building, as it stands out in relief against the
wooded ridge of Bunker's Hill. The celebrated gardens are adorned with
sculptures by Gabriel Gibber; Sir Joseph Paxton designed the great
conservatory, unrivalled in Europe, which covers an acre; and the
fountains, which include one with a jet 260 ft. high, are said to be
surpassed only by those at Versailles. Within the house there is a very
fine collection of pictures, including the well-known portraits by
Reynolds of Georgiana, duchess of Devonshire. Other paintings are
ascribed to Holbein, Dürer, Murillo, Jan van Eyck, Dolci, Veronese and
Titian. Hung in the gallery of sketches there are some priceless
drawings attributed to Michelangelo, Leonardo da Vinci, Raffaelle,
Correggio, Titian and other old masters. Statues by Canova, Thorwaldsen,
Chantrey and R.J. Wyatt are included among the sculptures. In the state
apartments the walls and window-panes are in some cases inlaid with
marble or porphyry; the woodcarving, marvellous for its intricacy, grace
and lightness of effect, is largely the work of Samuel Watson of Heanor
(d. 1715). Chatsworth Park is upwards of 11 m. in circuit, and contains
many noble forest-trees, the whole being watered by the Derwent, and
surrounded by high moors and uplands. Beyond the river, and immediately
opposite the house, stands the model village of Edensor, where most of
the cottages were built in villa style, with gardens, by order of the
6th duke. The parish church, restored by the same benefactor, contains
an old brass in memory of John Beaton, confidential servant to Mary,
queen of Scots, who died in 1570; and in the churchyard are the graves
of Lord Frederick Cavendish, murdered in 1882 in Phoenix Park, Dublin,
and of Sir Joseph Paxton.

Chatsworth (_Chetsvorde_, _Chetelsvorde_, "the court of Chetel") took
its name from Chetel, one of its Saxon owners, who held it of Edward the
Confessor. It belonged to the crown and was entrusted by the Conqueror
to the custody of William Peverell. Chatsworth afterwards belonged for
many generations to the family of Leech, and was purchased in the reign
of Elizabeth by Sir William Cavendish, husband of the famous Bess of
Hardwick. In 1557 he began to build Chatsworth House, and it was
completed after his death by his widow, then countess of Shrewsbury.
Here Mary, queen of Scots, spent several years of her imprisonment under
the care of the earl of Shrewsbury. During the Civil War, Chatsworth was
occasionally occupied as a fortress by both parties. It was pulled down,
and the present house begun by William, 1st duke of Devonshire in 1688.
The little village consists almost exclusively of families employed upon
the estate.



CHATTANOOGA, a city and the county-seat of Hamilton county, Tennessee,
U.S.A., in the S.E. part of the state, about 300 m. S. of Cincinnati,
Ohio, and 150 m. S.E. of Nashville, Tennessee, on the Tennessee river,
and near the boundary line between Tennessee and Georgia. Pop. (1860)
2545; (1870) 6093; (1880) 12,892; (1890) 29,100; (1900) 30,154, of whom
994 were foreign-born and 13,122 were negroes; (U.S. census, 1910)
44,604. The city is served by the Alabama Great Southern (Queen and
Crescent), the Cincinnati Southern (leased by the Cincinnati, New
Orleans & Texas Pacific railway company), the Nashville, Chattanooga &
St Louis (controlled by the Louisville & Nashville), and its leased
line, the Western & Atlantic (connecting with Atlanta, Ga.), the Central
of Georgia, and the Chattanooga Southern railways, and by freight and
passenger steamboat lines on the Tennessee river, which is navigable to
and beyond this point during eight months of the year. That branch of
the Southern railway extending from Chattanooga to Memphis was formerly
the Memphis & Charleston, under which name it became famous in the
American Civil War. Chattanooga occupies a picturesque site at a sharp
bend of the river. To the south lies Lookout Mountain, whose summit
(2126 ft. above the sea; 1495 ft. above the river) commands a
magnificent view. To the east rises Missionary Ridge. Fine driveways and
electric lines connect with both Lookout Mountain (the summit of which
is reached by an inclined plane on which cars are operated by cable)
and Missionary Ridge, where there are Federal reservations, as well as
with the National Military Park (15 sq. m.; dedicated 1895) on the
battlefield of Chickamauga (q.v.); this park was one of the principal
mobilization camps of the United States army during the Spanish-American
War of 1898. Among the principal buildings are the city hall, the
Federal building, the county court house, the public library, the high
school and the St Vincent's and the Baroness Erlanger hospitals. Among
Chattanooga's educational institutions are two commercial colleges, the
Chattanooga College for Young Ladies (non-sectarian), the Chattanooga
Normal University, and the University of Chattanooga, until June 1907,
United States Grant University (whose preparatory department, "The
Athens School," is at Athens, Tenn.), a co-educational institution under
Methodist Episcopal control, established in 1867; it has a school of law
(1899), a medical school (1889), and a school of theology (1888). East
of the city is a large national cemetery containing more than 13,000
graves of Federal soldiers. Chattanooga is an important produce, lumber,
coal and iron market, and is the principal trade and jobbing centre for
a large district in Eastern Tennessee and Northern Georgia and Alabama.
The proximity of coalfields and iron mines has made Chattanooga an iron
manufacturing place of importance, its plants including car shops, blast
furnaces, foundries, agricultural implement and machinery works, and
stove factories; the city has had an important part in the development
of the iron and steel industries in this part of the South. There are
also flour mills, tanneries (United States Leather Co.), patent
medicine, furniture, coffin, woodenware and wagon factories, knitting
and spinning mills, planing mills, and sash, door and blind
factories--the lumber being obtained from logs floated down the river
and by rail. The value of the city's factory products increased from
$10,517,886 in 1900 to $15,193,909 in 1905 or 44.5%.

Chattanooga was first settled about 1835, and was long known as Ross's
Landing. It was incorporated in 1851 as Chattanooga, and received a city
charter in 1866. Its growth for the three decades after the Civil War
was very rapid. During the American Civil War it was one of the most
important strategic points in the Confederacy, and in its immediate
vicinity were fought two great battles. During June 1862 it was
threatened by a Federal force under General O.M. Mitchel, but the
Confederate army of General Braxton Bragg was transferred thither by
rail from Corinth, Miss., before Mitchel was able to advance. In
September 1863, however, General W.S. Rosecrans, with the Union Army of
the Cumberland out-manoeuvred Bragg, concentrated his numerous columns
in the Chickamauga Valley, and occupied the town, to which, after the
defeat of Chickamauga (q.v.), he retired.

From the end of September to the 24th of November the Army of the
Cumberland was then invested in Chattanooga by the Confederates, whose
position lay along Missionary Ridge from its north end near the river
towards Rossville, whence their entrenchments extended westwards to
Lookout Mountain, which dominates the whole ground, the Tennessee
running directly beneath it. Thus Rosecrans was confined to a semicircle
of low ground around Chattanooga itself, and his supplies had to make a
long and difficult _détour_ from Bridgeport, the main road being under
fire from the Confederate position on Lookout and in the Wauhatchie
valley adjacent. Bragg indeed expected that Rosecrans would be starved
into retreat. But the Federals once more, and this time on a far larger
scale, concentrated in the face of the enemy. The XI. and XII. corps
from Virginia under Hooker were transferred by rail to reinforce
Rosecrans; other troops were called up from the Mississippi, and on the
16th of October the Federal government reconstituted the western armies
under the supreme command of General Grant. The XV. corps of the Army of
the Tennessee, under Sherman, was on the march from the Mississippi.
Hooker's troops had already arrived when Grant reached Chattanooga on
the 23rd of October. The Army of the Cumberland was now under Thomas,
Rosecrans having been recalled. The first action was fought at Brown's
Ferry in the Wauhatchie valley, where Hooker executed with complete
precision a plan for the revictualling of Chattanooga, established
himself near Wauhatchie on the 28th, and repulsed a determined attack on
the same night. But Sherman was still far distant, and the Federal
forces at Knoxville, against which a large detachment of Bragg's army
under Longstreet was now sent, were in grave danger. Grant waited for
Sherman's four divisions, but prepared everything for battle in the
meantime. His plan was that Thomas in the Chattanooga lines should
contain the Confederate centre on Missionary Ridge, while Hooker on the
right at Wauhatchie was to attack Lookout Mountain, and Sherman farther
up the river was to carry out the decisive attack against Bragg's
extreme right wing at the end of Missionary Ridgg. The last marches of
the XV. corps were delayed, by stormy weather, Bragg reinforced
Longstreet, and telegraphic communication between Grant and the Federals
at Knoxville had already ceased. But Grant would not move forward
without Sherman, and the battle of Chattanooga was fought more than two
months after Chickamauga. On the 23rd of November a forward move of
Thomas's army, intended as a demonstration, developed into a serious and
successful action, whereby the first line of the Confederate centre was
driven in for some distance. Bragg was now much weakened by successive
detachments having been sent to Knoxville, and on the 24th the real
battle began. Sherman's corps was gradually brought over the river near
the mouth of Chickamauga Creek, and formed up on the east side.

[Illustration: Confederate line of defence.]

The attack began at 1 P.M. and was locally a complete success. The
heights attacked were in Sherman's hands, and fortified against
counter-attack, before nightfall. Hooker in the meanwhile had fought the
"Battle above the Clouds" on the steep face of Lookout Mountain, and
though opposed by an equal force of Confederates, had completely driven
the enemy from the mountain. The 24th then had been a day of success for
the Federals, and the decisive attack of the three armies in concert was
to take place on the 25th. But the maps deceived Grant and Sherman as
they had previously deceived Rosecrans. Sherman had captured, not the
north point of Missionary Ridge, but a detached hill, and a new and more
serious action had to be fought for the possession of Tunnel Hill, where
Bragg's right now lay strongly entrenched. The Confederates used every
effort to hold the position and all Sherman's efforts were made in vain.
Hooker, who was moving on Rossville, had not progressed far, and Bragg
was still free to reinforce his right. Grant therefore directed Thomas
to move forward on the centre to relieve the pressure on Sherman. The
Army of the Cumberland was, after all, to strike the decisive blow.
About 3.30 P.M. the centre advanced on the Confederate's trenches at the
foot of Missionary Ridge. These were carried at the first rush, and the
troops were ordered to lie down and await orders. Then occurred one of
the most dramatic episodes of the war. Suddenly, and without orders
either from Grant or the officers at the front, the whole line of the
Army of the Cumberland rose and rushed up the ridge. Two successive
lines of entrenchments were carried at once. In a short time the crest
was stormed, and after a last attempt at resistance the enemy's centre
fled in the wildest confusion. The pursuit was pressed home by the
divisional generals, notably by Sheridan. Hooker now advanced in earnest
on Rossville, and by nightfall the whole Confederate army, except the
troops on Tunnel Hill, was retreating in disorder. These too were
withdrawn in the night, and the victory of the Federals was complete.
Bragg lost 8684 men killed, wounded and prisoners out of perhaps 34,000
men engaged; Grant, with 60,000 men, lost about 6000.



CHATTEL (for derivation see CATTLE), a term used in English law as
equivalent to "personal property," that is, property which, on the death
of the owner, devolves on his executor or administrator to be
distributed (unless disposed of by will) among the next of kin according
to the Statutes of Distributions. Chattels are divided into _chattels
real_ and _chattels personal_. Chattels real are those interests in land
for which no "real action" (see ACTION) lies; estates which are less
than freehold (estates for years, at will, or by sufferance) are
chattels real. Chattels personal are such things as belong immediately
to the person of the owner, and for which, if they are injuriously
withheld from him, he has no remedy other than by a personal action.
Chattels personal are divided into _choses in possession_ and _choses in
action_ (see CHOSE).

A chattel mortgage, in United States law, is a transfer of personal
property as security for a debt or obligation in such form that the
title to the property will pass to the mortgagee upon the failure of the
mortgagor to comply with the terms of the contract. At common law a
chattel mortgage might be made without writing, and was valid as between
the parties, and even as against third parties if accompanied by
possession in the mortgagee, but in most states of the Union legislation
now requires a chattel mortgage to be in writing and duly recorded in
order to be valid against third parties. At common law a mortgage can be
given only of chattels actually in existence and belonging to the
mortgagor, though if he acquired title afterwards the mortgage would be
good as between the parties, but not as against subsequent purchasers or
creditors. In equity, on the other hand, a chattel mortgage, though not
good as a conveyance, is valid as an executory agreement.

_Goods and chattels_ is a phrase which, in its widest signification,
includes any property other than freehold. The two words, however, have
come to be synonymous, and the expression, now practically confined to
wills, means merely things movable in possession.



CHATTERIS, a market town in the Wisbech parliamentary division of
Cambridgeshire, England, 25½ m. N. by W. of Cambridge by the Great
Eastern railway. Pop. of urban district (1901) 4711. It lies in the
midst of the flat Fen country. The church of St Peter is principally
Decorated; and there are fragments of a Benedictine convent founded in
the 10th century and rebuilt after fire in the first half of the 14th.
The town has breweries, and engineering and rope-making works. To the
north runs the great Forty-foot Drain, also called Vermuyden's, after
the Dutch engineer whose name is associated with the fen drainage works
of the middle of the 17th century.



CHATTERJI, BANKIM CHANDRA [BANKIMACHANDRA CHATTARADH-YAYA] (1838-1894),
Indian novelist, was born in the district of the Twenty-four Parganas in
Bengal on the 27th of June 1838, and was by caste a Brahman. He was
educated at the Hugli College, at the Presidency College in Calcutta,
and at Calcutta University, where he was the first to take the degree of
B.A. (1858). He entered the Indian civil service, and served as deputy
magistrate in various districts of Bengal, his official services being
recognized, on his retirement in 1891, by the title of rai bahadur and
the C.I.E. He died on the 8th of April 1894.

Bankim Chandra was beyond question the greatest novelist of India during
the 19th century, whether judged by the amount and quality of his
writings, or by the influence which they have continued to exercise. His
education had brought him into touch with the works of the great
European romance writers, notably Sir Walter Scott, and he created in
India a school of fiction on the European model. His first historical
novel, the _Durges-Nandini_ or _Chief's Daughter_, modelled on Scott,
made a great sensation in Bengal; and the _Kapala-Kundala_ and
_Mrinalini_, which followed it, established his fame as a writer whose
creative imagination and power of delineation had never been surpassed
in India. In 1872 he brought out his first social novel, the
_Biska-Brikkha_ or _Poison Tree_, which was followed by others in rapid
succession. It is impossible to exaggerate the effect they produced; for
over twenty years Bankim Chandra's novels were eagerly read by the
educated public of Bengal, including the Hindu ladies in the zenanas;
and though numerous works of fiction are now produced year by year in
every province of India, his influence has increased rather than
diminished. Of all his works, however, by far the most important from
its astonishing political consequences was the _Ananda Math_, which was
published in 1882, about the time of the agitation arising out of the
Ilbert Bill. The story deals with the Sannyasi (i.e. fakir or hermit)
rebellion of 1772 near Purmea, Tirhut and Dinapur, and its culminating
episode is a crushing victory won by the rebels over the united British
and Mussulman forces, a success which was not, however, followed up,
owing to the advice of a mysterious "physician" who, speaking as a
divinely-inspired prophet, advises Satyananda, the leader of "the
children of the Mother," to abandon further resistance, since a
temporary submission to British rule is a necessity; for Hinduism has
become too speculative and unpractical, and the mission of the English
in India is to teach Hindus how to reconcile theory and speculation with
the facts of science. The general moral of the _Ananda Math_, then, is
that British rule and British education are to be accepted as the only
alternative to Mussulman oppression, a moral which Bankim Chandra
developed also in his _Dharmatattwa_, an elaborate religious treatise in
which he explained his views as to the changes necessary in the moral
and religious condition of his fellow-countrymen before they could hope
to compete on equal terms with the British and Mahommedans. But though
the _Ananda Math_ is in form an apology for the loyal acceptance of
British rule, it is none the less inspired by the ideal of the
restoration, sooner or later, of a Hindu kingdom in India. This is
especially evident in the occasional verses in the book, of which the
_Bande Mataram_ is the most famous.

As to the exact significance of this poem a considerable controversy has
raged. _Bande Mataram_ is the Sanskrit for "Hail to thee, Mother!" or
more literally "I reverence thee, Mother!", and according to Dr G.A.
Grierson (_The Times_, Sept. 12, 1906) it can have no other possible
meaning than an invocation of one of the "mother" goddesses of Hinduism,
in his opinion Kali "the goddess of death and destruction." Sir Henry
Cotton, on the other hand (ib. Sept. 13, 1906), sees in it merely an
invocation of the "mother-land" Bengal, and quotes in support of this
view the free translation of the poem by the late W.H. Lee, a proof
which, it may be at once said, is far from convincing. But though, as Dr
Grierson points out, the idea of a "mother-land" is wholly alien to
Hindu ideas, it is quite possible that Bankim Chandra may have
assimilated it with his European culture, and the true explanation is
probably that given by Mr J.D. Anderson in _The Times_ of September 24,
1906. He points out that in the 11th chapter of the 1st book of the
_Ananda Math_ the Sannyasi rebels are represented as having erected, in
addition to the image of Kali, "the Mother who Has Been," a white marble
statue of "the Mother that Shall Be," which "is apparently a
representation of the mother-land. The _Bande Mataram_ hymn is
apparently addressed to both idols."

The poem, then, is the work of a Hindu idealist who personified Bengal
under the form of a purified and spiritualized Kali. Of its thirty-six
lines, partly written in Sanskrit, partly in Bengali, the greater number
are harmless enough. But if the poet sings the praise of the "Mother"

  "As Lachmi, bowered in the flower
   That in the water grows,"

he also praises her as "Durga, bearing ten weapons," and lines 10, 11
and 12 are capable of very dangerous meanings in the mouths of
unscrupulous agitators. Literally translated these run, "She has seventy
millions of throats to sing her praise, twice seventy millions of hands
to fight for her, how then is Bengal powerless?" As S.M. Mitra points
out (_Indian Problems_, London, 1908), this language is the more
significant as the _Bande Mataram_ in the novel was the hymn by singing
which the Sannyasis gained strength when attacking the British forces.

During Bankim Chandra Chatterji's lifetime the _Bande Mataram_, though
its dangerous tendency was recognized, was not used as a party war-cry;
it was not raised, for instance, during the Ilbert Bill agitation, nor
by the students who flocked round the court during the trial of Surendra
Nath Banerji in 1883. It has, however, obtained an evil notoriety in the
agitations that followed the partition of Bengal. That Bankim Chandra
himself foresaw or desired any such use of it is impossible to believe.
According to S.M. Mitra, he composed it "in a fit of patriotic
excitement after a good hearty dinner, which he always enjoyed. It was
set to Hindu music, known as the _Mallar-Kawali-Tal_. The
extraordinarily stirring character of the air, and its ingenious
assimilation of Bengali passages with Sanskrit, served to make it
popular."

Circumstances have made the _Bande Mataram_ the most famous and the most
widespread in its effects of Bankim Chandra's literary works. More
permanent, it may be hoped, was the wholesome influence he exercised on
the number of literary men he gathered round him, who have left their
impress on the literature of Bengal. In his earlier years he served his
apprenticeship in literature under Iswar Chandra Vidyasagar, the chief
poet and satirist of Bengal during the earlier half of the 19th century.
Bankim Chandra's friend and colleague, Dina Bandhu Mitra, was virtually
the founder of the modern Bengali drama. Another friend of his, Hem
Chandra Banerji, was a poet of recognized merit and talent. And among
the younger men who venerated Bankim Chandra, and benefited by his
example and advice, may be mentioned two distinguished poets, Nalein
Chandra Sen and Rabindra Nath Tagore.

Of Bankim Chandra's novels some have been translated into English by
H.A.D. Phillips and by Mrs M.S. Knight.



CHATTERTON, THOMAS (1752-1770), English poet, was born at Bristol on the
20th of November 1752. His pedigree has a curious significance. The
office of sexton of St Mary Redcliffe, at Bristol, one of the most
beautiful parish churches in England, had been transmitted for nearly
two centuries in the Chatterton family; and throughout the brief life of
the poet it was held by his uncle, Richard Phillips. The poet's father,
Thomas Chatterton, was a musical genius, somewhat of a poet, a
numismatist, and a dabbler in occult arts. He was one of the
sub-chanters of Bristol cathedral, and master of the Pyle Street free
school, near Redcliffe church. But whatever hereditary tendencies may
have been transmitted from the father, the sole training of the boy
necessarily devolved on his mother, who was in the fourth month of her
widowhood at the time of his birth. She established a girls' school,
took in sewing and ornamental needlework, and so brought up her two
children, a girl and a boy, till the latter attained his eighth year,
when he was admitted to Colston's Charity. But the Bristol blue-coat
school, in which the curriculum was limited to reading, writing,
arithmetic and the Church Catechism, had little share in the education
of its marvellous pupil. The hereditary race of sextons had come to
regard the church of St Mary Redcliffe as their own peculiar domain;
and, under the guidance of his uncle, the child found there his
favourite haunt. The knights, ecclesiastics and civic dignitaries,
recumbent on its altar tombs, became his familiar associates; and by and
by, when he was able to spell his way through the inscriptions graven on
their monuments, he found a fresh interest in certain quaint oaken
chests in the muniment room over the porch on the north side of the
nave, where parchment deeds, old as the Wars of the Roses, long lay
unheeded and forgotten. They formed the child's playthings almost from
his cradle. He learned his first letters from the illuminated capitals
of an old musical folio, and learned to read out of a black-letter
Bible. He did not like, his sister said, reading out of small books.
Wayward, as it seems, almost from his earliest years, and manifesting no
sympathy with the ordinary pastimes of children, he was regarded for a
time as deficient in intellect. But he was even then ambitious of
distinction. His sister relates that on being asked what device he would
like painted on a bowl that was to be his, he replied, "Paint me an
angel, with wings, and a trumpet, to trumpet my name over the world."

From his earliest years he was liable to fits of abstraction, sitting
for hours in seeming stupor, or yielding after a time to tears, for
which he would assign no reason. He had no one near him to sympathize in
the strange world of fancy which his imagination had already called into
being; and circumstances helped to foster his natural reserve, and to
beget that love of mystery which exercised so great an influence on the
development of his genius. When the strange child had attained his sixth
year his mother began to recognize his capacity; at eight he was so
eager for books that he would read and write all day long if
undisturbed; and in his eleventh year he had become a contributor to
_Felix Farley's Bristol Journal_. The occasion of his confirmation
inspired some religious poems published in this paper. In 1763 a
beautiful cross of curious workmanship, which had adorned the churchyard
of St Mary Redcliffe for upwards of three centuries, was destroyed by a
churchwarden. The spirit of veneration was strong in the boy, and he
sent to the local journal on the 7th of January 1764 a clever satire on
the parish Vandal. But his delight was to lock himself in a little attic
which he had appropriated as his study; and there, with books, cherished
parchments, saved from the loot of the muniment room of St Mary
Redcliffe, and drawing materials, the child lived in thought with his
15th-century heroes and heroines. The first of his literary
mystifications, the duologue of "Elinoure and Juga," was written before
he was twelve years old, and he showed his poem to the usher at
Colston's hospital, Thomas Phillips, as the work of a 15th-century poet.

Chatterton remained an inmate of Colston's hospital for upwards of six
years, and the slight advantages gained from this scanty education are
traceable to the friendly sympathy of Phillips, himself a writer of
verse, who encouraged his pupils to write. Three of Chatterton's
companions are named as youths whom Phillips's taste for poetry
stimulated to rivalry; but Chatterton held aloof from these contests,
and made at that time no confidant of his own more daring literary
adventures. His little pocket-money was spent in borrowing books from a
circulating library; and he early ingratiated himself with book
collectors, by whose aid he found access to Weever, Dugdale and Collins,
as well as to Speght's edition of Chaucer, Spenser and other books.

His "Rowleian" jargon appears to have been chiefly the result of the
study of John Kersey's _Dictionarium Anglo-Britannicum_, and Prof. W. W.
Skeat seems to think his knowledge of even Chaucer was very slight. His
holidays were mostly spent at his mother's house; and much of them in
the favourite retreat of his attic study there. He had already conceived
the romance of Thomas Rowley, an imaginary monk of the 15th century, and
lived for the most part in an ideal world of his own, in that elder time
when Edward IV. was England's king, and Master William Canynge--familiar
to him among the recumbent effigies in Redcliffe church--still ruled in
Bristol's civic chair. Canynge is represented as an enlightened patron
of literature, and Rowley's dramatic interludes were written for
performance at his house. In order to escape a marriage urged by the
king, Canynge retired to the college of Westbury in Gloucestershire,
where he enjoyed the society of Rowley, and eventually became dean of
the institution. In "The Storie of William Canynge," one of the shorter
pieces of his ingenious romance, his early history is recorded.

  "Straight was I carried back to times of yore,
   Whilst Canynge swathed yet in fleshly bed,
   And saw all actions which had been before,
     And all the scroll of Fate unravelled;
   And when the fate-marked babe acome to sight,
   I saw him eager gasping after light.
   In all his sheepen gambols and child's play,
     In every merrymaking, fair, or wake,
   I kenn'd a perpled light of wisdom's ray;
     He ate down learning with the wastel-cake;
   As wise as any of the aldermen,
   He'd wit enow to make a mayor at ten."

This beautiful picture of the childhood of the ideal patron of Rowley is
in reality that of the poet himself--"the fate-marked babe," with his
wondrous child-genius, and all his romantic dreams realized. The
literary masquerade which thus constituted the life-dream of the boy was
wrought out by him in fragments of prose and verse into a coherent
romance, until the credulous scholars and antiquaries of his day were
persuaded into the belief that there had lain in the parish chest of
Redcliffe church for upwards of three centuries, a collection of MSS. of
rare merit, the work of Thomas Rowley, an unknown priest of Bristol in
the days of Henry VI. and his poet laureate, John Lydgate.

Among the Bristol patrons of Chatterton were two pewterers, George
Catcott and his partner Henry Burgum. Catcott was one of the most
zealous believers in Rowley, and continued to collect his reputed
writings long after the death of their real author. On Burgum, who had
risen in life by his own exertions, the blue-coat boy palmed off the de
Bergham pedigree, and other equally apocryphal evidences of the
pewterer's descent from an ancestry old as the Norman Conquest. The de
Bergham quartering, blazoned on a piece of parchment doubtless recovered
from the Redcliffe muniment chest, was itself supposed to have lain for
centuries in that ancient depository. The pedigree was professedly
collected by Chatterton from original records, including "The Rowley
MSS." The pedigree still exists in Chatterton's own handwriting, copied
into a book in which he had previously transcribed portions of antique
verse, under the title of "Poems by Thomas Rowley, priest of St. John's,
in the city of Bristol"; and in one of these, "The Tournament," Syrr
Johan de Berghamme plays a conspicuous part. The ennobled pewterer
rewarded Chatterton with five shillings, and was satirized for this
valuation of a noble pedigree in some of Chatterton's latest verse.

On the 1st of July 1767, Chatterton was transferred to the office of
John Lambert, attorney, to whom he was bound apprentice as a clerk.
There he was left much alone; and after fulfilling the routine duties
devolving on him, he found leisure for his own favourite pursuits. An
ancient stone bridge on the Avon, built in the reign of Henry II., and
altered by many later additions into a singularly picturesque but
inconvenient thoroughfare, had been displaced by a structure better
adapted to modern requirements. In September 1768, when Chatterton was
in the second year of his apprenticeship, the new bridge was partially
opened for traffic. Shortly afterwards the editor of _Felix Farley's
Journal_ received from a correspondent, signing himself _Dunelmus
Bristoliensis_, a "description of the mayor's first passing over the old
bridge," professedly derived from an ancient MS. William Barrett,
F.S.A., surgeon and antiquary, who was then accumulating materials for a
history of Bristol, secured the original manuscript, which is now
preserved in the British Museum, along with other Chatterton MSS., most
of which were ultimately incorporated by the credulous antiquary into a
learned quarto volume, entitled the _History and Antiquities of the City
of Bristol_, published nearly twenty years after the poet's death. It
was at this time that the definite story made its appearance--over
which critics and antiquaries wrangled for nearly a century--of
numerous ancient poems and other MSS. taken by the elder Chatterton from
a coffer in the muniment room of Redcliffe church, and transcribed, and
so rescued from oblivion, by his son. The pieces include the "Bristowe
Tragedie, or the Dethe of Syr Charles Bawdin," a ballad celebrating the
death of the Lancastrian knight, Charles Baldwin; "Ælla," a "Tragycal
Enterlude," as Chatterton styles it, but in reality a dramatic poem of
sustained power and curious originality of structure; "Goddwyn," a
dramatic fragment; "Tournament," "Battle of Hastings," "The Parliament
of Sprites," "Balade of Charitie," with numerous shorter pieces, forming
altogether a volume of poetry, the rare merit of which is indisputable,
wholly apart from the fact that it was the production of a mere boy.
Unfortunately for him, his ingenious romance had either to be
acknowledged as his own creation, and so in all probability be treated
with contempt, or it had to be sustained by the manufacture of spurious
antiques. To this accordingly Chatterton resorted, and found no
difficulty in gulling the most learned of his credulous dupes with his
parchments.

The literary labours of the boy, though diligently pursued at his desk,
were not allowed to interfere with the duties of Mr Lambert's office.
Nevertheless the Bristol attorney used to search his apprentice's
drawer, and tear up any poems or other manuscripts that he could lay his
hands upon; so that it was only during the absences of Mr Lambert from
Bristol that he was able to expend his unemployed time in his favourite
pursuits. But repeated allusions, both by Chatterton and others, seem to
indicate that such intervals of freedom were of frequent occurrence.
Some of his modern poems, such as the piece entitled "Resignation," are
of great beauty; and these, with the satires, in which he took his
revenge on all the local celebrities whose vanity or meanness had
excited his ire, are alone sufficient to fill a volume. The Catcotts,
Burgum, Barrett and others of his patrons, figure in these satires, in
imprudent yet discriminating caricature, along with mayor, aldermen,
bishop, dean and other notabilities of Bristol. Towards Lambert his
feelings were of too keen a nature to find relief in such sarcasm.

In December 1768, in his seventeenth year, he wrote to Dodsley, the
London publisher, offering to procure for him "copies of several ancient
poems, and an interlude, perhaps the oldest dramatic piece extant, wrote
by one Rowley, a priest in Bristol, who lived in the reigns of Henry VI.
and Edward IV." To this letter he appended the initials of his favourite
pseudonym, _Dunelmus Bristoliensis_, but directed the answer to be sent
to the care of Thomas Chatterton, Redcliffe Hill, Bristol. To this, as
well as to another letter enclosing an extract from the tragedy of
"Ælla," no answer appears to have been returned. Chatterton, conceiving
the idea of finding sympathy and aid at the hand of some modern Canynge,
bethought him of Horace Walpole, who not only indulged in a medieval
renaissance of his own, but was the reputed author of a spurious antique
in the _Castle of Otranto_. He wrote to him offering him a document
entitled "The Ryse of Peyncteyne yn Englande, wroten by T. Rowleie,
1469, for Mastre Canynge," accompanied by notes which included specimens
of Rowley's poetry. To this Walpole replied with courteous
acknowledgments. He characterized the verses as "wonderful for their
harmony and spirit," and added, "Give me leave to ask you where Rowley's
poems are to be had? I should not be sorry to print them; or at least a
specimen of them, if they have never been printed." Chatterton replied,
enclosing additional specimens of antique verse, and telling Walpole
that he was the son of a poor widow, and clerk to an attorney, but had a
taste for more refined studies; and he hinted a wish that he might help
him to some more congenial occupation. Walpole's manner underwent an
abrupt change. The specimens of verse had been submitted to his friends
Gray and Mason, the poets, and pronounced modern. They did not thereby
forfeit the wonderful harmony and spirit which Walpole had already
professed to recognize in them. But he now coldly advised the boy to
stick to the attorney's office; and "when he should have made a
fortune," he might betake himself to more favourite studies, Chatterton
had to write three times before he recovered his MSS. Walpole has been
loaded with more than his just share of responsibility for the fate of
the unhappy poet, of whom he admitted when too late, "I do not believe
there ever existed so masterly a genius."

Chatterton now turned his attention to periodical literature and
politics, and exchanged _Felix Farley's Bristol Journal_ for the _Town
and County Magazine_ and other London periodicals. Assuming the vein of
Junius--then in the full blaze of his triumph--he turned his pen against
the duke of Grafton, the earl of Bute, and the princess of Wales. He had
just despatched one of his political diatribes to the _Middlesex
Journal_, when he sat down on Easter Eve, I7th April 1770, and penned
his "Last Will and Testament," a strange satirical compound of jest and
earnest, in which he intimated his intention of putting an end to his
life the following evening. Among his satirical bequests, such as his
"humility" to the Rev. Mr Camplin, his "religion" to Dean Barton, and
his "modesty" along with his "prosody and grammar" to Mr Burgum, he
leaves "to Bristol all his spirit and disinterestedness, parcels of
goods unknown on its quay since the days of Canynge and Rowley." In more
genuine earnestness he recalls the name of Michael Clayfield, a friend
to whom he owed intelligent sympathy. The will was probably purposely
prepared in order to frighten his master into letting him go. If so, it
had the desired effect. Lambert cancelled his indentures; his friends
and acquaintance made him up a purse; and on the 25th or 26th of the
month he arrived in London.

Chatterton was already known to the readers of the _Middlesex Journal_
as a rival of Junius, under the _nom de plume_ of Decimus. He had also
been a contributor to Hamilton's _Town and County Magazine_, and
speedily found access to the _Freeholder's Magazine_, another political
miscellany strong for Wilkes and liberty. His contributions were freely
accepted; but the editors paid little or nothing for them. He wrote in
the most hopeful terms to his mother and sister, and spent his first
earnings in buying gifts for them. His pride and ambition were amply
gratified by the promises and interested flattery of editors and
political adventurers; Wilkes himself had noted his trenchant style,
"and expressed a desire to know the author"; and Lord Mayor Beckford
graciously acknowledged a political address of his, and greeted him "as
politely as a citizen could." But of actual money he received but
little. He was extremely abstemious, his diligence was great, and his
versatility wonderful. He could assume the style of Junius or Smollett,
reproduce the satiric bitterness of Churchill, parody Macpherson's
Ossian, or write in the manner of Pope, or with the polished grace of
Gray and Collins. He wrote political letters, eclogues, lyrics, operas
and satires, both in prose and verse. In June 1770--after Chatterton had
been some nine weeks in London--he removed from Shoreditch, where he had
hitherto lodged with a relative, to an attic in Brook Street, Holborn.
But for most of his productions the payment was delayed; and now state
prosecutions of the press rendered letters in the Junius vein no longer
admissible, and threw him back on the lighter resources of his pen. In
Shoreditch, as in his lodging at the Bristol attorney's, he had only
shared a room; but now, for the first time, he enjoyed uninterrupted
solitude. His bed-fellow at Mr Walmsley's, Shoreditch, noted that much
of the night was spent by him in writing; and now he could write all
night. The romance of his earlier years revived, and he transcribed from
an imaginary parchment of the old priest Rowley his "Excelente Balade of
Charitie." This fine poem, perversely disguised in archaic language, he
sent to the editor of the _Town and County Magazine_, and had it
rejected.

The high hopes of the sanguine boy had begun to fade. He had not yet
completed his second month in London, and already failure and starvation
stared him in the face. Mr Cross, a neighbouring apothecary, repeatedly
invited him to join him at dinner or supper; but he refused. His
landlady also, suspecting his necessity, pressed him to share her
dinner, but in vain. "She knew," as she afterwards said, "that he had
not eaten anything for two or three days." But he was offended at her
urgency, and assured her that he was not hungry. The note of his actual
receipts, found in his pocket-book after his death, shows that
Hamilton, Fell and other editors who had been so liberal in flattery,
had paid him at the rate of a shilling for an article, and somewhat less
than eightpence each for his songs; while much which had been accepted
was held in reserve, and still unpaid for. The beginning of a new month
revealed to him the indefinite postponement of the publication and
payment of his work. He had wished, according to his foster-mother, to
study medicine with Barrett; in his desperation he now reverted to this,
and wrote to Barrett for a letter to help him to an opening as a
surgeon's assistant on board an African trader. He appealed also to Mr
Catcott to forward his plan, but in vain. On the 24th of August 1770, he
retired for the last time to his attic in Brook Street, carrying with
him the arsenic which he there drank, after tearing into fragments
whatever literary remains were at hand.

He was only seventeen years and nine months old; but the best of his
numerous productions, both in prose and verse, require no allowance to
be made for the immature years of their author, when comparing him with
the ablest of his contemporaries. He pictures Lydgate, the monk of Bury
St Edmunds, challenging Rowley to a trial at versemaking, and under
cover of this fiction, produces his "Songe of Ælla," a piece of rare
lyrical beauty, worthy of comparison with any antique or modern
production of its class. Again, in his "Tragedy of Goddwyn," of which
only a fragment has been preserved, the "Ode to Liberty," with which it
abruptly closes, may claim a place among the finest martial lyrics in
the language. The collection of poems in which such specimens occur
furnishes by far the most remarkable example of intellectual precocity
in the whole history of letters. Collins, Burns, Keats, Shelley and
Byron all awaken sorrow over the premature arrestment of their genius;
but the youngest of them survived to his twenty-fifth year, while
Chatterton was not eighteen when he perished in his miserable garret.
The death of Chatterton attracted little notice at the time; for the few
who then entertained any appreciative estimate of the Rowley poems
regarded him as their mere transcriber. He was interred in a
burying-ground attached to Shoe Lane Workhouse, in the parish of St
Andrew's, Holborn, which has since been converted into a site for
Farringdon Market. There is a discredited story that the body of the
poet was recovered, and secretly buried by his uncle, Richard Phillips,
in Redcliffe Churchyard. There a monument has since been erected to his
memory, with the appropriate inscription, borrowed from his "Will," and
so supplied by the poet's own pen--"To the memory of Thomas Chatterton.
Reader! judge not. If thou art a Christian, believe that he shall be
judged by a Superior Power. To that Power only is he now answerable."

  BIBLIOGRAPHY.--_Poems supposed to have been written at Bristol by
  Thomas Rowley and others, in the Fifteenth Century_ (1777) was edited
  by Thomas Tyrwhitt; Thomas Warton, in his _History of English Poetry_
  (1778), vol. ii. section viii., gives Rowley a place among the 15th
  century poets; but neither of these critics believed in the antiquity
  of the poems. In 1782 a new edition of Rowley's poems appeared, with a
  "Commentary, in which the antiquity of them is considered and
  defended," by Jeremiah Milles, dean of Exeter. The controversy which
  raged round the Rowley poems is discussed in A. Kippis, _Biographia
  Britannica_ (vol. iv., 1789), where there is a detailed account by G.
  Gregory of Chatterton's life (pp. 573-619). This was reprinted in the
  edition (1803) of Chatterton's _Works_ by R. Southey and J. Cottle,
  published for the benefit of the poet's sister. The neglected
  condition of the study of earlier English in the 18th century alone
  accounts for the temporary success of Chatterton's mystification. It
  has long been agreed that Chatterton was solely responsible for the
  Rowley Poems, but the language and style are analysed in confirmation
  of this view by Prof. W.W. Skeat in an introductory essay prefaced to
  vol. ii. of _The Poetical Works of Thomas Chatterton_ (1871) in the
  "Aldine Edition of the British Poets." This, which is the most
  convenient edition, also contains a memoir of the poet by Edward Bell.
  The spelling of the Rowley poems is there modernized, and many of the
  archaic words are replaced by modern equivalents provided in many
  cases from Chatterton's own notes, the theory being that Chatterton
  usually composed in modern English, and inserted his peculiar words
  and his complicated orthography afterwards. For some criticism of
  Prof. Skeat's success in the very difficult task of reconstituting the
  text, see H.B. Forman, _Thomas Chatterton and his latest Editor_
  (1874). The Chatterton MSS., originally in the possession of William
  Barrett of Bristol, were left by his heir to the British Museum in
  1800. Others are preserved in the Bristol library.

  Chatterton's genius and his tragic death are commemorated by Shelley
  in _Adonais_, by Wordsworth in "Resolution and Independence," by
  Coleridge in "A Monody on the Death of Chatterton," by D.G. Rossetti
  in "Five English Poets," and John Keats inscribed _Endymion_ "to the
  memory of Thomas Chatterton." Alfred de Vigny's drama of _Chatterton_
  gives an altogether fictitious account of the poet. Herbert Croft
  (q.v.), in his _Love and Madness_, interpolated a long and valuable
  account of Chatterton, giving many of the poet's letters, and much
  information obtained from his family and friends (pp. 125-244, letter
  li.). There is a valuable collection of "Chattertoniana" in the
  British Museum, consisting of separate works by Chatterton, newspaper
  cuttings, articles, dealing with the Rowley controversy and other
  subjects, with MS. notes by Joseph Haslewood, and several autograph
  letters.

  Among biographies of Chatterton may be mentioned _Chatterton: A
  Biographical Study_ (1869), by Daniel Wilson; _Chatterton: A
  Biography_ (1899; first printed 1856 in a volume of essays), by D.
  Masson; "Thomas Chatterton" (1900), by Helene Richter, in _Wiener
  Beiträge zur engl. Philologie; Chatterton_, by C.E. Russell (1909).



CHATTI, an ancient German tribe inhabiting the upper reaches of the
rivers Weser, Eder, Fulda and Werra, a district approximately
corresponding to Hesse-Cassel, though probably somewhat more extensive.
They frequently came into conflict with the Romans during the early
years of the 1st century. Eventually they formed a portion of the Franks
and were incorporated in the kingdom of Clovis probably with the
Ripuarii, at the beginning of the 6th century.

Tacitus, _Annals_, i. 2, II, 12, 13; _Germania_, 30-31; Strabo p. 291 f.



CHAUCER, GEOFFREY


  Life

(? 1340-1400), English poet. The name Chaucer, a
French form of the Latin _calcearius_, a shoe-maker, is found in London
and the eastern counties as early as the second half of the 13th
century. Some of the London Chaucers lived in Cordwainer Street, in the
shoemakers' quarter; several of them, however, were vintners, and among
others the poet's father John, and probably also his grandfather Robert.
Legal pleadings inform us that in December 1324 John Chaucer was not
much over twelve years old, and that he was still unmarried in 1328, the
year which used to be considered that of Geoffrey's birth. [Sidenote:
Life.] The poet was probably born from eight to twelve years later,
since in 1386, when giving evidence in Sir Richard le Scrope's suit
against Sir Robert Grosvenor as to the right to bear certain arms, he
was set down as "del age de xl ans et plus, armeez par xxvij ans." At a
later date, and probably at the time of the poet's birth, his father
lived in Thames Street, and had to wife a certain Agnes, niece of Hamo
de Compton, whom we may regard as Geoffrey Chaucer's mother. In 1357
Geoffrey is found, apparently as a lad, in the service of Elizabeth,
countess of Ulster, wife of Lionel, duke of Clarence, entries in two
leaves of her household accounts, accidentally preserved, showing that
she paid in April, May and December various small sums for his clothing
and expenses. In 1359, as we learn from his deposition in the Scrope
suit, Chaucer went to the war in France. At some period of the campaign
he was at "Retters," i.e. Rethel, near Reims, and subsequently had the
ill luck to be taken prisoner. On the 1st of March 1360 the king
contributed £16 to his ransom, and by a year or two later Chaucer must
have entered the royal service, since on the 20th of June 1367 Edward
granted him a pension of twenty marks for his past and future services.
A pension of ten marks had been granted by the king the previous
September to a Philippa Chaucer for services to the queen as one of her
"domicellae" or "damoiselles," and it seems probable that at this date
Chaucer was already married and this Philippa his wife, a conclusion
which used to be resisted on the ground of allusions in his early poems
to a hopeless love-affair, now reckoned part of his poetical outfit.
Philippa is usually said to have been one of two daughters of a Sir
Payne Roet, the other being Katherine, who after the death of her first
husband, Sir Hugh de Swynford, in 1372, became governess to John of
Gaunt's children, and subsequently his mistress and (in 1396) his wife.
It is possible that Philippa was sister to Sir Hugh and sister-in-law to
Katherine. In either case the marriage helps to account for the favour
subsequently shown to Chaucer by John of Gaunt.

In the grant of his pension Chaucer is called "dilectus vallectus
noster," our beloved yeoman; before the end of 1368 he had risen to be
one of the king's esquires. In September of the following year John of
Gaunt's wife, the duchess Blanche, died at the age of twenty-nine, and
Chaucer wrote in her honour _The Book of the Duchesse_, a poem of 1334
lines in octosyllabic couplets, the first of his undoubtedly genuine
works which can be connected with a definite date. In June 1370 he went
abroad on the king's service, though on what errand, or whither it took
him, is not known. He was back probably some time before Michaelmas, and
seems to have remained in England till the 1st of December 1372, when he
started, with an advance of 100 marks in his pocket, for Italy, as one
of the three commissioners to treat with the Genoese as to an English
port where they might have special facilities for trade. The accounts
which he delivered on his return on the 23rd of May 1373 show that he
had also visited Florence on the king's business, and he probably went
also to Padua and there made the acquaintance of Petrarch.

In the second quarter of 1374 Chaucer lived in a whirl of prosperity. On
the 23rd of April the king granted him a pitcher of wine daily,
subsequently commuted for an annuity of 20 marks. From John of Gaunt,
who in August 1372 had granted Philippa Chaucer £10 a year, he himself
now received (June 13) a like annuity in reward for his own and his
wife's services. On the 8th of June he was appointed Comptroller of the
Custom and Subsidy of Wools, Hides and Woodfells and also of the Petty
Customs of Wine in the Port of London. A month before this appointment,
and probably in anticipation of it, he took (May 10, 1374) a lease for
life from the city of London of the dwelling-house above the gate of
Aldgate, and here he lived for the next twelve years. His own and his
wife's income now amounted to over £60, the equivalent of upwards of
£1000 in modern money. In the next two years large windfalls came to him
in the form of two wardships of Kentish heirs, one of whom paid him
£104, and a grant of £71: 4: 6; the value of some confiscated wool. In
December 1376 he was sent abroad on the king's service in the retinue of
Sir John Burley; in February 1377 he was sent to Paris and Montreuil in
connexion probably with the peace negotiations between England and
France, and at the end of April (after a reward of £20 for his good
services) he was again despatched to France.

On the accession of Richard II. Chaucer was confirmed in his offices and
pensions. In January 1378 he seems to have been in France in connexion
with a proposed marriage between Richard and the daughter of the French
king; and on the 28th of May of the same year he was sent with Sir
Edward de Berkeley to the lord of Milan and Sir John Hawkwood to treat
for help in the king's wars, returning on the 19th of September. This
was his last diplomatic journey, and the close of a period of his life
generally considered to have been so unprolific of poetry that little
beyond the Clerk's "Tale of Grisilde," one or two other of the stories
afterwards included in the _Canterbury Tales_, and a few short poems,
are attributed to it, though the poet's actual absences from England
during the eight years amount to little more than eighteen months.
During the next twelve or fifteen years there is no question that
Chaucer was constantly engaged in literary work, though for the first
half of them he had no lack of official employment. Abundant favour was
shown him by the new king. He was paid £22 as a reward for his later
missions in Edward III.'s reign, and was allowed an annual gratuity of
10 marks in addition to his pay of £10 as comptroller of the customs of
wool. In April 1382 a new comptrollership, that of the petty customs in
the Port of London, was given him, and shortly after he was allowed to
exercise it by deputy, a similar licence being given him in February
1385, at the instance of the earl of Oxford, as regards the
comptrollership of wool. In October 1385 Chaucer was made a justice of
the peace for Kent. In February 1386 we catch a glimpse of his wife
Philippa being admitted to the fraternity of Lincoln cathedral in the
company of Henry, earl of Derby (afterwards Henry IV.), Sir Thomas de
Swynford and other distinguished persons. In August 1386 he was elected
one of the two knights of the shire for Kent, and with this dignity,
though it was one not much appreciated in those days, his good fortune
reached its climax. In December of the same year he was superseded in
both his comptrollerships, almost certainly as a result of the absence
of his patron, John of Gaunt, in Spain, and the supremacy of the duke of
Gloucester. In the following year the cessation of Philippa's pension
suggests that she died between Midsummer and Michaelmas. In May 1388
Chaucer surrendered to the king his two pensions of 20 marks each, and
they were re-granted at his request to one John Scalby. The transaction
was unusual and probably points to a pressing need for ready money, nor
for the next fourteen months do we know of any source of income
possessed by Chaucer beyond his annuity of £10 from John of Gaunt.

In July 1389, after John of Gaunt had returned to England, and the king
had taken the government into his own hands, Chaucer was appointed clerk
of the works at various royal palaces at a salary of two shillings a
day, or over £31 a year, worth upwards of £500 present value. To this
post was subsequently added the charge of some repairs at St George's
Chapel, Windsor. He was also made a commissioner to maintain the banks
of the Thames between Woolwich and Greenwich, and was given by the earl
of March (grandson of Lionel, duke of Clarence, his old patron) a
sub-forestership at North Petherton, Devon, obviously a sinecure. While
on the king's business, in September 1390, Chaucer was twice robbed by
highwaymen, losing £20 of the king's money. In June 1391 he was
superseded in his office of clerk of the works, and seems to have
suffered another spell of misfortune, of which the first alleviation
came in January 1393 when the king made him a present of £10. In
February 1394 he was granted a new pension of £20. It is possible, also,
that about this time, or a little later, he was in the service of the
earl of Derby. In 1397 he received from King Richard a grant of a butt
of wine yearly. For this he appears to have asked in terms that suggest
poverty, and in May 1398 he obtained letters of protection against his
creditors, a step perhaps rendered necessary by an action for debt taken
against him earlier in the year. On the accession of Henry IV. a new
pension of 40 marks was conferred on Chaucer (13th of October 1399) and
Richard II.'s grants were formally confirmed. Henry himself, however,
was probably straitened for ready money, and no instalment of the new
pension was paid during the few months of his reign that the poet lived.
Nevertheless, on the strength of his expectations, on the 24th of
December 1399 he leased a tenement in the garden of St Mary's Chapel,
Westminster, and it was probably here that he died, on the 25th of the
following October. He was buried in Westminster Abbey, and his tomb
became the nucleus of what is now known as Poets' Corner.

The portrait of Chaucer, which the affection of his disciple, Thomas
Hoccleve, caused to be painted in a copy of the latter's _Regement of
Princes_ (now Harleian MS. 4866 in the British Museum), shows him an old
man with white hair; he has a fresh complexion, grey eyes, a straight
nose, a grey moustache and a small double-pointed beard. His dress and
hood are black, and he carries in his hands a string of beads. We may
imagine that it was thus that during the last months of his life he used
to walk about the precincts of the Abbey.


  Works.

Henry IV.'s promise of an additional pension was doubtless elicited by
the _Compleynt to his Purs_, in the envoy to which Chaucer addresses him
as the "conquerour of Brutes Albioun." Thus within the last year of his
life the poet was still writing. Nevertheless, as early as 1393-1394, in
lines to his friend Scogan, he had written as if his day for poetry were
past, and it seems probable that his longer poems were all composed
before this date. In the preceding fifteen--or, if another view be
taken, twenty--years, his literary activity was very great, and with the
aid of the lists of his works which he gives in the _Legende of Good
Women_ (lines 414-431), and the talk on the road which precedes the "Man
of Law's Tale" (_Canterbury Tales_, B. 46-76), the order in which his
main works were written can be traced with approximate certainty,[1]
while a few both of these and of the minor poems can be connected with
definite dates.

The development of his genius has been attractively summed up as
comprised in three stages, French, Italian and English, and there is a
rough approximation to the truth in this formula, since his earliest
poems are translated from the French or based on French models, and the
two great works of his middle period are borrowed from the Italian,
while his latest stories have no such obvious and direct originals and
in their humour and freedom anticipate the typically English temper of
Henry Fielding. But Chaucer's indebtedness to French poetry was no
passing phase. For various reasons--a not very remote French origin of
his own family may be one of them--he was in no way interested in older
English literature or in the work of his English contemporaries, save
possibly that of "the moral Gower." On the other hand he knew the _Roman
de la rose_ as modern English poets know Shakespeare, and the full
extent of his debt to his French contemporaries, not merely in 1369, but
in 1385 and in 1393 (the dates are approximate), is only gradually being
discovered. To be in touch throughout his life with the best French
poets of the day was much for Chaucer. Even with their stimulus alone he
might have developed no small part of his genius. But it was his great
good fortune to add to this continuing French influence, lessons in plot
and construction derived from Boccaccio's _Filostrato_ and _Teseide_, as
well as some glimpses of the higher art of the _Divina Commedia_. He
shows acquaintance also with one of Petrarch's sonnets, and though, when
all is said, the Italian books with which he can be proved to have been
intimate are but few, they sufficed. His study of them was but an
episode in his literary life, but it was an episode of unique
importance. Before it began he had already been making his own artistic
experiments, and it is noteworthy that while he learnt so much from
Boccaccio he improved on his originals as he translated them. Doubtless
his busy life in the service of the crown had taught him
self-confidence, and he uses his Italian models in his own way and with
the most triumphant and assured success. When he had no more Italian
poems to adapt he had learnt his lesson. The art of weaving a plot out
of his own imagination was never his, but he could take what might be
little more than an anecdote and lend it body and life and colour with a
skill which has never been surpassed.

The most direct example of Chaucer's French studies is his translation
of _Le Roman de la rose_, a poem written in some 4000 lines by Guillaume
Lorris about 1237 and extended to over 22,000 by Jean Clopinel, better
known as Jean de Meun, forty years later. We know from Chaucer himself
that he translated this poem, and the extant English fragment of 7698
lines was generally assigned to him from 1532, when it was first
printed, till its authorship was challenged in the early years of the
Chaucer Society. The ground of this challenge was its wide divergence
from Chaucer's practice in his undoubtedly genuine works as to certain
niceties of rhyme, notable as to not rhyming words ending in _-y_ with
others ending _-ye_. It was subsequently discovered, however, that the
whole fragment was divisible linguistically into three portions, of
which the first and second end respectively at lines 1705 and 5810, and
that in the first of these three sections the variations from Chaucer's
accepted practice are insignificant. Lines 1-1705 have therefore been
provisionally accepted as Chaucer's, and the other two fragments as the
work of unknown translators (James I. of Scotland has been suggested as
one of them), which somehow came to be pieced together. If, however, the
difficulties in the way of this theory are less than those which
confront any other, they are still considerable, and the question can
hardly be treated as closed.

While our knowledge of Chaucer's _Romaunt of the Rose_ is in this
unsatisfactory state, another translation of his from the French, the
_Book of the Lyon_ (alluded to in the "Retraction" found, in some
manuscripts, at the end of the _Canterbury Tales_), which must certainly
have been taken from Guillaume Machault's _Le Dit du lion_, has
perished altogether. The strength of French influence on Chaucer's early
work may, however, be amply illustrated from the first of his poems with
which we are on sure ground, the _Book of the Duchesse_, or, as it is
alternatively called, the _Deth of Blaunche_. Here not only are
individual passages closely imitated from Machault and Froissart, but
the dream, the May morning, and the whole machinery of the poem are
taken over from contemporary French conventions. But even at this stage
Chaucer could prove his right to borrow by the skill with which he makes
his materials serve his own purpose, and some of the lines in the _Deth
of Blaunche_ are among the most tender and charming he ever wrote.

Chaucer's _A.B.C._, a poem in honour of the Blessed Virgin, of which the
stanzas begin with the successive letters of the alphabet, is another
early example of French influence. It is taken from the _Pèlerinage de
la vie humaine_, written by Guillaume de Deguilleville about 1330. The
occurrence of some magnificent lines in Chaucer's version, combined with
evidence that he did not yet possess the skill to translate at all
literally as soon as rhymes had to be considered, accounts for this poem
having been dated sometimes earlier than the _Book of the Duchesse_, and
sometimes several years later. With it is usually moved up and down,
though it should surely be placed in the 'seventies, the _Compleynt to
Pity_, a fine poem which yet, from its slight obscurity and absence of
Chaucer's usual ease, may very well some day prove to be a translation
from the French.

While Chaucer thus sought to reproduce both the matter and the style of
French poetry in England, he found other materials in popular Latin
books. Among his lost works are renderings of "Origenes upon the
Maudeleyne," and of Pope Innocent III. on "The Wreced Engendring of
Mankinde" (_De miseria conditionis humanae_). He must have begun his
attempts at straightforward narrative with the _Lyf of Seynt Cecyle_
(the weakest of all his works, the second Nun's Tale in the Canterbury
series) from the _Legenda Aurea_ of Jacobus de Voragine, and the story
of the patience of Grisilde, taken from Petrarch's Latin version of a
tale by Boccaccio. In both of these he condenses a little, but ventures
on very few changes, though he lets his readers see his impatience with
his originals. In his story of Constance (afterwards ascribed to the Man
of Law), taken from the Anglo-Norman chronicle of Nicholas Trivet,
written about 1334, we find him struggling to put some substance into
another weak tale, but still without the courage to remedy its radical
faults, though here, as with Grisilde, he does as much for his heroine
as the conventional exaltation of one virtue at a time permitted. It is
possible that other tales which now stand in the Canterbury series were
written originally at this period. What is certain is that at some time
in the 'seventies three or four Italian poems passed into Chaucer's
possession, and that he set to work busily to make use of them. One of
the most interesting of the poems reclaimed for him by Professor Skeat
is a fragmentary "Compleynt," part of which is written in _terza rima_.
While he thus experimented with the metre of the _Divina Commedia_, he
made his first attempt to use the material provided by Boccaccio's
_Teseide_ in another fragment of great interest, that of _Quene Anelida
and Fals Arcyte_. More than a third of this is taken up with another,
and quite successful, metrical experiment in Anelida's "compleynt," but
in the introduction of Anelida herself Chaucer made the first of his
three unsuccessful efforts to construct a plot for an important poem out
of his own head, and the fragment which begins so well breaks off
abruptly at line 357.

For a time the _Teseide_ seems to have been laid aside, and it was
perhaps at this moment, in despondency at his failure, that Chaucer
wrote his most important prose work, the translation of the _De
Consolatione Philosophiae_ of Boethius. Reminiscences of this helped to
enrich many of his subsequent poems, and inspired five of his shorter
pieces (_The Former Age, Fortune, Truth, Gentilesse_ and _Lak of
Stedfastnesse_), but the translation itself was only a partial success.
To borrow his own phrase, his "Englysh was insufficient" to reproduce
such difficult Latin. The translation is often barely intelligible
without the original, and it is only here and there that it flows with
any ease or rhythm.

If Chaucer felt this himself he must have been speedily consold by
achieving in _Troilus and Criseyde_ his greatest artistic triumph.
Warned by his failure in _Anelida and Arcyte_, he was content this time
to take his plot unaltered from the _Filostrato_, and to follow
Boccaccio step by step through the poem. But he did not follow him as a
mere translator. He had done his duty manfully for the saints "of other
holinesse" in Cecyle, Grisilde and Constance, whom he was forbidden by
the rules of the game to clothe with complete flesh and blood. In this
great love-story there were no such restrictions, and the characters
which Boccaccio's treatment left thin and conventional became in
Chaucer's hands convincingly human. No other English poem is so instinct
with the glory and tragedy of youth, and in the details of the story
Chaucer's gifts of vivid colouring, of humour and pity, are all at their
highest.

An unfortunate theory that the reference in the _Legends of Good Women_
to "al the love of Palamon and Arcyte" is to a hypothetical poem in
seven-line stanzas on this theme, which Chaucer is imagined, when he
came to plan the _Canterbury Tales_, to have suppressed in favour of a
new version in heroic couplets, has obscured the close connexion in
temper and power between what we know as the "Knight's Tale" and the
_Troilus_. The poem may have been more or less extensively revised
before, with admirable fitness, it was assigned to the Knight, but that
its main composition can be separated by several years from that of
_Troilus_ is aesthetically incredible. Chaucer's art here again is at
its highest. He takes the plot of Boccaccio's _Teseide_, but only as
much of it as he wants, and what he takes he heightens and humanizes
with the same skill which he had shown in transforming the _Filostrato_.
Of the individual characters Theseus himself, the arbiter of the plot,
is most notably developed; Emilie and her two lovers receive just as
much individuality as they will bear without disturbing the atmosphere
of romance. The whole story is pulled together and made more rapid and
effective. A comparison of almost any scene as told by the two poets
suffices to show Chaucer's immense superiority. At some subsequent
period the "Squire's Tale" of Cambuscan, the fair Canacee and the Horse
of Brass, was gallantly begun in something of the same key, but Chaucer
took for it more materials than he could use, and for lack of the help
of a leader like Boccaccio he was obliged to leave the story, in
Milton's phrase, "half-told," though the fragment written certainly
takes us very much less than half-way.

Meanwhile, in connexion (as is reasonably believed) with the betrothal
or marriage of Anne of Bohemia to Richard II. (i.e. about 1381-1382),
Chaucer had brought to a successful completion the _Parlement of
Foules_, a charming sketch of 699 lines, in which the other birds, on
Saint Valentine's day, counsel the "Formel Egle" on her choice of a
mate. His success here, as in the case of the _Deth of Blaunche the
Duchesse_, was due to the absence of any need for a climax; and though
the materials which he borrowed were mainly Latin (with some help from
passages of the _Teseide_ not fully needed for _Palamon and Arcyte_) his
method of handling them would have been quite approved by his friends
among the French poets. A more ambitious venture, the _Hous of Fame_, in
which Chaucer imagines himself borne aloft by an eagle to Fame's temple,
describes what he sees and hears there, and then breaks off in apparent
inability to get home, shows a curious mixture of the poetic ideals of
the _Roman de la rose_ and reminiscences of the _Divina Commedia_.

As the _Hous of Fame_ is most often remembered and quoted for the
personal touches and humour of Chaucer's conversation with the eagle, so
the most-quoted passages in the Prologue to the _Legende of Good Women_
are those in which Chaucer professes his affection for the daisy, and
the attack on his loyalty by Cupid and its defence by Alceste. Recent
discoveries have shown, however, that (besides obligations to Machault)
some of the touches about the daisy and the controversy between the
partisans of the Flower and of the Leaf are snatches from poems by his
friends Froissart and Deschamps, which Chaucer takes up and returns to
them with pretty compliments, and that he was indebted to Froissart for
some of the framework of his poem.[2] Both of the two versions of the
Prologue to the _Legende_ are charming, and some of the tales, notably
that of Cleopatra, rank with Chaucer's best work. When, however, he had
written eight and part of the ninth he tired of his scheme, which was
planned to celebrate nineteen of Cupid's faithful "saints," with
Alcestis as their queen. With his usual hopefulness he had overlooked
the risk of monotony, which obviously weighed heavily on him ere he
broke off, and the loss of the other ten stories is less to be regretted
than that of the celebration of Alceste, and a possible epilogue which
might have exceeded in charm the Prologue itself.


  Canterbury Tales.

Chaucer's failure to complete the scheme of the _Legende of Good Women_
may have been partly due to the attractions of the _Canterbury Tales_,
which were probably taken up in immediate succession to it. His
guardianship of two Kentish wards, his justiceship of the peace, his
representing the county in the parliament of 1386, his commissionership
of the river-bank between Greenwich and Woolwich, all make it easy to
understand his dramatic use of the merry crowds he saw on the Canterbury
road, without supposing him to have had recourse to Boccaccio's
_Decamerone_, a book which there is no proof of his having seen. The
pilgrims whom he imagines to have assembled at the Tabard Inn in
Southwark, where Harry Bailey was host, are said to have numbered "wel
nyne and twenty in a company," and the Prologue gives full-length
sketches of a Knight, a Squire (his son), and their Yeoman; of a
Prioress, Monk, Friar, Oxford Clerk, and Parson, with two disreputable
hangers-on of the church, a Summoner and Pardoner; of a Serjeant-at-Law
and a Doctor of Physic, and of a Franklin, or country gentleman,
Merchant, Shipman, Miller, Cook, Manciple, Reeve, Ploughman (the
Parson's brother) and the ever-famous Wife of Bath. Five London
burgesses are described in a group, and a Nun and Priest[3] are
mentioned as in attendance on the Prioress. Each of these, with Chaucer
himself making the twenty-ninth, was pledged to tell two tales, but
including one second attempt and a tale told by the Yeoman of a Canon,
who overtakes the pilgrims on the road, we have only twenty finished
stories, two unfinished and two interrupted ones. As in the case of the
_Legende of Good Women_, our loss is not so much that of the additional
stories as of the completed framework. The wonderful character sketches
of the Prologue are carried yet farther by the Talks on the Road which
link the different tales, and two of these Talks, in which the Wife of
Bath and the Pardoner respectively edify the company, have the
importance of separate Tales, but between the Tales that have come down
to us there are seven links missing,[4] and it was left to a later and
weaker hand to narrate, in the "Tale of Beryn," the adventures of the
pilgrims at Canterbury.

The reference to the _Lyf of Seynt Cecyle_ in the Prologue to the
_Legende of Good Women_ gives external proof that Chaucer included
earlier work in the scheme of the _Canterbury Tales_, and mention has
been made of other stories which are indisputably early. In the absence
of any such metrical tests as have proved useful in the case of
Shakespeare, the dates at which several of the Tales were composed
remain doubtful, while in the case of at least two, the Clerk's tale of
Grisilde and the Monk's tragedies, there is evidence of early work being
revised and supplemented. It is fortunately impossible to separate the
prologue to the charmingly told story of "yonge Hugh of Lincoln" from
the tale itself, and with the "quod sche" in the second line as proof
that Chaucer was here writing specially for his Prioress we are
forbidden to limit the new stories to any one metre or tone. There can
be no doubt, however, that what may be called the Tales of the Churls
(Miller, Reeve, Summoner, Friar, &c.), and the conversational
outpourings of the Pardoner and Wife of Bath, form, with the immortal
Prologue, the most important and distinctive additions to the older
work. In these, and in the Pardoner's story of Death and the Three
Revellers, and the Nun's Priest's masterly handling of the fable of the
Cock and Fox, both of them free from the grossness which marks the
others, Chaucer takes stories which could have been told in a short page
of prose and elaborates them with all the skill in narration which he
had sedulously cultivated. The conjugal reminiscences of the Wife of
Bath and the Reeve's Tale with its abominable climax (lightened a little
by Aleyn's farewell, lines 316-319) are among the great things in
Chaucer, as surely as _Troilus_, and _Palamon and Arcyte_ and the
_Prologue_. They help notably to give him the width of range which may
certainly be claimed for him.

In or soon after 1391 Chaucer wrote in prose for an eleven-year-old
reader, whom he addresses as "Litel Lowis my son," a treatise on the use
of the Astrolabe, its short prologue being the prettiest specimen of his
prose. The wearisome tale of "Melibee and his wyf Prudence," which was
perhaps as much admired in English as it had been in Latin and French,
may have been translated at any time. The sermon on Penitence, used as
the Parson's Tale, was probably the work of his old age. "Envoys" to his
friends Scogan and Bukton, a translation of some balades by Sir Otes de
Granson, and the _Compleynt to his Purs_ complete the record of his
minor poetry. We have his own statement that in his youth he had written
many Balades, Roundels and Virelayes in honour of Love, and the two
songs embedded respectively in the _Parlement of Foules_ and the
Prologue to the _Legende of Good Women_ are charming and musical. His
extant shorter poems, however, whether early or late, offer no excuse
for claiming high rank for him as a lyrist. He had very little sheer
singing power, and though there are fine lines in his short poems,
witness the famous "Flee fro the prees and dwell with soothfastnesse,"
they lack the sustained concentration of great work. From the drama,
again, Chaucer was cut off, and it is idle to argue from the innumerable
dramatic touches in his poems and his gift of characterization as to
what he might have done had he lived two centuries later. His own age
delighted in stories, and he gave it the stories it demanded invested
with a humanity, a grace and strength which place him among the world's
greatest narrative poets, and which bring the England of his own day,
with all the colour and warmth of life, wonderfully near to all his
readers.


  Influence.

The part played by Chaucer in the development of the English language
has often been overrated. He neither corrupted it, as used to be said,
by introducing French words which it would otherwise have avoided, nor
bore any such part in fixing it as was afterwards played by the
translators of the Bible. When he was growing up educated society in
England was still bilingual, and the changes in vocabulary and
pronunciation which took place during his life were the natural results
of a society, which had been bilingual with a bias towards French,
giving an exclusive preference to English. The practical identity of
Chaucer's language with that of Gower shows that both merely used the
best English of their day with the care and slightly conservative
tendency which befitted poets. Chaucer's service to the English language
lies in his decisive success having made it impossible for any later
English poet to attain fame, as Gower had done, by writing alternatively
in Latin and French. The claim which should be made for him is that, at
least as regards poetry, he proved that English was "sufficient."

Chaucer borrowed both his stanza forms and his "decasyllabic" couplets
(mostly with an extra syllable at the end of the line) from Guillaume
Machault, and his music, like that of his French master and his
successors, depends very largely on assigning to every syllable its full
value, and more especially on the due pronunciation of the final -_e_.
The slower movement of change in Scotland allowed time for Chaucer to
exercise a potent influence on Scottish poetry, but in England this
final -_e_, to which most of the earlier grammatical forms by Chaucer's
time had been reduced, itself fell rapidly into disuse during the 15th
century, and a serious barrier was thus raised to the appreciation of
the artistic value of his verse. His disciples, Hoccleve and Lydgate,
who at first had caught some echoes of his rhythms, gradually yielded to
the change in pronunciation, so that there was no living tradition to
hand down his secret, while successive copyists reduced his text to a
state in which it was only by accident that lines could be scanned
correctly. For fully three centuries his reputation was sustained solely
by his narrative power, his warmest panegyrists betraying no
consciousness that they were praising one of the greatest technical
masters of poetry. Even when thus maimed, however, his works found
readers and lovers in every generation, and every improvement in his
text has set his fame on a surer basis.

  BIBLIOGRAPHY.--The _Canterbury Tales_ have always been Chaucer's most
  popular work, and, including fragments, upwards of sixty 15th-century
  manuscripts of it still survive. Two thin volumes of his minor poems
  were among the little quartos which Caxton printed by way of
  advertisement immediately on his return to England; the _Canterbury
  Tales_ and _Boethius_ followed in 1478, _Troilus_ and a second edition
  of the _Tales_ in 1483, the _Hous of Fame_ in 1484. The _Canterbury
  Tales_ were subsequently printed in 1492 (Pynson), 1498 (de Worde) and
  1526 (Pynson); _Troilus_ in 1517 (de Worde) and 1526 (Pynson); the
  _Hous of Fame_ in 1526 (Pynson); the _Parlement of Foules_ in 1526
  (Pynson) and 1530 (de Worde), and the _Mars_, "_Venus_" and _Envoy to
  Bukton_ by Julyan Notary about 1500. Pynson's three issues in 1526
  almost amounted to a collected edition, but the first to which the
  title _The Workes of Geffray Chaucer_ was given was that edited by
  William Thynne in 1532 for Thomas Godfray. Of this there was a new
  edition in 1542 for John Reynes and William Bonham, and an undated
  reprint a few years later for Bonham, Kele, Petit and Toye, each of
  whom put his name on part of the edition. In 1561 a reprint, with
  numerous additions, edited by John Stowe, was printed by J. Kyngston
  for J. Wight, and this was re-edited, with fresh additions by Thomas
  Speght, in 1598 for G. Bishop and again in 1602 for Adam Islip. In
  1687 there was an anonymous reprint, and in 1721 John Urry produced
  the last and worst of the folios. By this time the paraphrasers were
  already at work, Dryden rewriting the tales of the Knight, the Nun's
  Priest and the Wife of Bath, and Pope the Merchant's. In 1737
  (reprinted in 1740) the Prologue and Knight's Tale were edited
  (anonymously) by Thomas Morell "from the most authentic manuscripts,"
  and here, though by dint of much violence and with many mistakes,
  Chaucer's lines were for the first time in print given in a form in
  which they could be scanned. This promise of better things (Morell
  still thought it necessary to accompany his text with the paraphrases
  by Betterton and Dryden) was fulfilled by a fine edition of the
  _Canterbury Tales_ (1775-1778), in which Thomas Tyrwhitt's scholarly
  instincts produced a comparatively good text from second-rate
  manuscripts and accompanied it with valuable illustrative notes. The
  next edition of any importance was that edited by Thomas Wright for
  the Percy Society in 1848-1851, based on the erratic but valuable
  British Museum manuscript Harley 7334, containing readings which must
  be either Chaucer's second thoughts or the emendations of a
  brilliantly clever scribe. In 1866 Richard Morris re-edited this text
  in a more scholarly manner for the Aldine edition of the British
  Poets, and in the following year produced for the Clarendon Press
  Series a school edition of the Prologue and Tales of the Knight and
  Nun's Priest, edited with the fulness and care previously bestowed
  only on Greek and Latin classics.

  In 1868 the foundation of the Chaucer Society, with Dr Furnivall as
  its director and chief worker, and Henry Bradshaw as a leading spirit,
  led to the publication of a six-text edition of the _Canterbury
  Tales_, and the consequent discovery that a manuscript belonging to
  the Earl of Ellesmere, though undoubtedly "edited," contained the best
  available text. The Chaucer Society also printed the best manuscripts
  of _Troilus and Criseyde_ and of all the minor poems, and thus cleared
  the way for the "Oxford" Chaucer, edited by Professor Skeat, with a
  wealth of annotation, for the Clarendon Press in 1894, the text of
  which was used for the splendid folio printed two years later by
  William Morris at the Kelmscott Press, with illustrations by Sir
  Edward Burne-Jones. A supplementary volume of the Oxford edition,
  entitled _Chaucerian and other Pieces_, issued by Professor Skeat in
  1897, contains the prose and verse which his early publishers and
  editors, from Pynson and Thynne onwards, included among his Works by
  way of illustration, but which had gradually come to be regarded as
  forming part of his text. The reasons for their rejection are fully
  stated by Professor Skeat in the work named and also in _The Chaucer
  Canon_ (1900). Many of these pieces have now been traced to other
  authors, and their exclusion has helped to clear not only Chaucer's
  text but also his biography, which used (as in the "Life" published by
  William Godwin in two quarto volumes in 1803) to be encumbered with
  inferences from works now known not to be Chaucer's, notably the
  _Testament of Love_ written by Thomas Usk. All information about
  Chaucer's life available in 1900 will be found summarized by Mr R.E.G.
  Kirk in _Life-Records of Chaucer_, part iv., published by the Chaucer
  Society in that year. See also _Chaucer; a Bibliographical Manual_, by
  Eleanor P. Hammond (1909).      (A. W. Po.)


FOOTNOTES:

  [1] The positions of the _House of Fame_ and _Palamon and Arcyte_
    are still matters of controversy.

  [2] The French influences on this Prologue, its connexion with the
    Flower and the Leaf controversy, and the priority of what had
    previously been reckoned as the second or "B" form of the Prologue
    over the "A," were demonstrated in papers by Prof. Kittredge on
    "Chaucer and some of his Friends" in _Modern Philology_, vol. i.
    (Chicago, 1903), and by Mr J. L. Lowes on "The Prologue to the
    Legend of Good Women" in _Publications of the Modern Language
    Association of America_, vol. xix., December 1904.

  [3] The Talks on the Road show clearly that only one Priest in
    attendance on the Prioress, and two tales to each narrator, were
    originally contemplated, but the "Prestes _thre_" in line 164 of the
    Prologue, and the bald couplet (line 793 sq.) explaining that each
    pilgrim was to tell two tales _each way_, were probably both
    alterations made by Chaucer in moments of amazing hopefulness. The
    journey was reckoned a 3½ days' ride, and eight or nine tales a day
    would surely have been a sufficient allowance.

  [4] The absence of these links necessitates the division of the
    _Canterbury Tales_ into nine groups, to which, for purposes of
    quotation, the letters A to I have been assigned, the line
    numeration of the Tales in each group being continuous.



CHAUDESAIGUES, a village of central France, in the department of Cantal,
at the foot of the mountains of Aubrac, 19 m. S.S.W. of St Flour by
road. Pop. (1906) town, 937; commune, 1558. It is celebrated for its hot
mineral springs, which vary in temperature from 135° to 177° Fahr., and
at their maximum rank as the hottest in France. The water, which
contains bicarbonate of soda, is employed not only medicinally (for
rheumatism, &c.), but also for the washing of fleeces, the incubation of
eggs, and various other economic purposes; and it furnishes a ready
means of heating the houses of the town during winter. In the immediate
neighbourhood is the cold chalybeate spring of Condamine. The warm
springs were known to the Romans, and are mentioned by Sidonius
Apollinaris.



CHAUFFEUR (from Fr. _chauffer_), to heat, a term primarily used in French
of a man in charge of a forge or furnace, and so of a stoker on a
locomotive or in a steamship, but in its anglicized sense more
particularly confined to a professional driver of a motor vehicle. (See
also BRIGANDAGE.)



CHAULIEU, GUILLAUME AMFRYE DE (1639-1720), French poet and wit, was born
at Fontenay, Normandy, in 1639. His father, _maître des comptes_ of
Rouen, sent him to study at the Collège de Navarre. Guillaume early
showed the wit that was to distinguish him, and gained the favour of the
duke of Vendôme, who procured for him the abbey of Aumale and other
benefices. Louis Joseph, duke of Vendôme, and his brother Philippe,
grand prior of the Knights of Malta in France, at that time had a joint
establishment at the Temple, where they gathered round them a very gay
and reckless circle. Chaulieu became the constant companion and adviser
of the two princes. He made an expedition to Poland in the suite of the
marquis de Béthune, hoping to make a career for himself in the court of
John Sobieski; he saw one of the Polish king's campaigns in Ukraine, but
returned to Paris without securing any advancement. Saint-Simon says
that the abbé helped his patron the grand prior to rob the duke of
Vendôme, and that the king sent orders that the princes should take the
management of their affairs from him. This account has been questioned
by Sainte-Beuve, who regards Saint-Simon as a prejudiced witness. In his
later years Chaulieu spent much time at the little court of the duchesse
du Maine at Sceaux. There he became the trusted and devoted friend of
Mdlle Delaunay, with whom he carried on an interesting correspondence.
Among his poems the best known are "Fontenay" and "La Retraite."
Chaulieu died on the 27th of June 1720.

  His works were edited with those of his friend the marquis de la Fare
  in 1714, 1750 and 1774. See also C.A. Sainte-Beuve, _Causeries du
  lundi_, vol. i.; and _Lettres inédites_ (1850), with a notice by
  Raymond, marquis de Berenger.



CHAUMETTE, PIERRE GASPARD (1763-1794), French revolutionist, was born at
Nevers. Until the Revolution he lived a somewhat wandering life,
interesting himself particularly in botany. He was a student of medicine
at Paris in 1790, became one of the orators of the club of the
Cordeliers, and contributed anonymously to the _Révolutions de Paris_.
As member of the insurrectionary Commune of the 10th of August 1792, he
was delegated to visit the prisons, with full power to arrest suspects.
He was accused later of having taken part in the massacres of September,
but was able to prove that at that time he had been sent by the
provisional executive council to Normandy to oversee a requisition of
60,000 men. Returning from this mission, he pronounced an eloquent
discourse in favour of the republic. His simple manners, easy speech,
ardent temperament and irreproachable private life gave him great
influence in Paris, and he was elected president of the Commune,
defending the municipality in that capacity at the bar of the Convention
on the 31st of October 1792. Re-elected in the municipal elections of
the 2nd of December 1792, he was soon charged with the functions of
procurator of the Commune, and contributed with success to the
enrolments of volunteers by his appeals to the populace. Chaumette was
one of the ringleaders in the attacks of the 31st of May and of the 2nd
of June 1793 on the Girondists, toward whom he showed himself
relentless. He demanded the formation of a revolutionary army, and
preached the extermination of all traitors. He was one of the promoters
of the worship of Reason, and on the 10th of November 1793 he presented
the goddess to the Convention in the guise of an actress. On the 23rd of
the same month he obtained a decree closing all the churches of Paris,
and placing the priests under strict surveillance; but on the 25th he
retraced his steps and obtained from the Commune the free exercise of
worship. He wished to save the Hébertists by a new insurrection and
struggled against Robespierre; but a revolutionary decree promulgated by
the Commune on his demand was overthrown by the Convention. Robespierre
had him accused with the Hébertists; he was arrested, imprisoned in the
Luxembourg, condemned by the Revolutionary tribunal and executed on the
13th of April 1794. Chaumette's career had its brighter side. He was an
ardent social reformer; he secured the abolition of corporal punishment
in the schools, the suppression of lotteries, of houses of ill-fame and
of obscene literature; he instituted reforms in the hospitals, and
insisted on the honours of public burial for the poor.

  Chaumette left some printed speeches and fragments, and memoirs
  published in the _Amateur d'autographes_. His memoirs on the 10th of
  August were published by F.A. Aulard, preceded by a biographical
  study.



CHAUMONT-EN-BASSIGNY, a town of eastern France, capital of the
department of Haute-Marne, a railway junction 163 m. E.S.E. of Paris on
the main line of the Eastern railway to Belfort. Pop. (1906) 12,089.
Chaumont is picturesquely situated on an eminence between the rivers
Marne and Suize in the angle formed by their confluence. To the west a
lofty viaduct over the Suize carries the railway. The church of
St-Jean-Baptiste dates from the 13th century, the choir and lateral
chapels belonging to the 15th and 16th. In the interior the sculptured
triforium (15th century), the spiral staircase in the transept and a
Holy Sepulchre are of interest. The lycée and the hospital have chapels
of the 17th and 16th centuries respectively. The Tour Hautefeuille (a
keep of the 11th century) is the principal relic of a château of the
counts of Champagne; the rest of the site is occupied by the law courts.
In the Place de l'Escargot stands a statue of the chemist Philippe Lebon
(1767-1804), born in Haute-Marne. Chaumont is the seat of a prefect and
of a court of assizes, and has tribunals of first instance and of
commerce, a lycée, training colleges, and a branch of the Bank of
France. The main industries are glove-making and leather-dressing. The
town has trade in grain, iron, mined in the vicinity, and leather. In
1190 it received a charter from the counts of Champagne. It was here
that in 1814 Great Britain, Austria, Russia and Prussia concluded the
treaty (dated March 1, signed March 9) by which they severally bound
themselves not to conclude a separate peace with Napoleon, and to
continue the war until France should have been reduced within the
boundaries of 1792.



CHAUNCEY, ISAAC (1772-1840), American naval commander, was born at Black
Rock, Connecticut, on the 20th of February 1772. He was brought up in
the merchant service, and entered the United States navy as a lieutenant
in 1798. His first services were rendered against the Barbary pirates.
During these operations, more especially at Tripoli, he greatly
distinguished himself, and was voted by Congress a sword of honour,
which, however, does not appear to have been given him. The most active
period of his life is that of his command on the Lakes during the War
of 1812. He took the command at Sackett's Harbor on Lake Ontario in
October 1812. There was at that time only one American vessel, the brig
"Oneida" (16), and one armed prize, a schooner, on the lake. But
Commodore Chauncey brought from 400 to 500 officers and men with him,
and local resources for building being abundant, he had by November
formed a squadron of ten vessels, with which he attacked the Canadian
port, York, taking it in April 1813, capturing one vessel and causing
the destruction of another then building. He returned to Sackett's
Harbor. In May Sir James Lucas Yeo (1732-1818) came out from England
with some 500 officers and men, to organize a squadron for service on
the Lakes. By the end of the month he was ready for service with a
squadron of eight ships and brigs, and some small craft. The governor,
Sir G. Prevost, gave him no serious support. On the 29th of May, during
Chauncey's absence at Niagara, the Americans were attacked at Sackett's
Harbor and would have been defeated if Prevost had not insisted on a
retreat at the very moment when the American shipbuilding yard was in
danger of being burnt, with a ship of more than eight hundred tons on
the stocks. The retreat of the British force gave Chauncey time to
complete this vessel, the "General Pike," which was so far superior to
anything under Yeo's command that she was said to be equal in effective
strength to the whole of the British flotilla. The American commodore
was considered by many of his subordinates to have displayed excessive
caution. In August he skirmished with Sir James Yeo's small squadron of
six vessels, but made little effective use of his own fourteen. Two of
his schooners were upset in a squall, with the loss of all hands, and he
allowed two to be cut off by Yeo. Commodore Chauncey showed a preference
for relying on his long guns, and a disinclination to come to close
quarters. He was described as chasing the British squadron all round the
lake, but his encounters did not go beyond artillery duels at long
range, and he allowed his enemy to continue in existence long after he
might have been destroyed. The winter suspended operations, and both
sides made exertions to increase their forces. The Americans had the
advantage of commanding greater resources for shipbuilding. Sir James
Yeo began by blockading Sackett's Harbor in the early part of 1814, but
when the American squadron was ready he was compelled to retire by the
disparity of the forces. The American commodore was now able to blockade
the British flotilla at Kingston. When the cruising season of the lake
was nearly over he in his turn retired to Sackett's Harbor, and did not
leave it for the rest of the war. During his later years he served as
commissioner of the navy, and was president of the board of naval
commissioners from 1833 till his death at Washington on the 27th of
February 1840.

  See Roosevelt's _War of 1812_ (1882); and A. T. Mahan, _Sea-Power in
  its Relations to the War of 1812_ (1905).



CHAUNCY, CHARLES-(1592-1672), president of Harvard College, was born at
Yardley-Bury, Hertfordshire, England, in November 1592, and was educated
at Trinity College, Cambridge, of which he became a fellow. He was in
turn vicar at Ware, Hertfordshire (1627-1633), and at Marston St
Lawrence, Northamptonshire (1633-1637). Refusing to observe the
ecclesiastical regulations of Archbishop Laud, he was brought before the
court of high commission in 1629, and again in 1634, when, for opposing
the placing of a rail around the communion table, he was suspended and
imprisoned. His formal recantation in February 1637 caused him lasting
self-reproach and humiliation. In 1637 he emigrated to America, and from
1638 until 1641 was an associate pastor at Plymouth, where, however, his
advocacy of the baptism of infants by immersion caused dissatisfaction.
He was the pastor at Scituate, Massachusetts, from 1641 until 1654, and
from 1654 until his death was president of Harvard College, as the
successor of the first president Henry Dunster (c. 1612-1659). He died
on the 19th of February 1672. By his sermons and his writings he exerted
a great influence in colonial Massachusetts, and according to Mather was
"a most incomparable scholar." His writings include: _The Plain Doctrine
of the Justification of a Sinner in the Sight of God_ (1659) and
_Antisynodalia Scripta Americana_ (1662). His son, Isaac Chauncy
(1632-1712), who removed to England, was a voluminous writer on
theological subjects.

  There are biographical sketches of President Chauncy in Cotton
  Mather's _Magnalia Christi Americana_. (London, 1702), and in W.C.
  Fowler's _Memorials of the Chauncys, including President Chauncy_
  (Boston, 1858).

President Chauncy's great-grandson, CHARLES CHAUNCY (1705-1787), a
prominent American theologian, was born in Boston, Massachusetts, on the
1st of January 1705, and graduated at Harvard in 1721. In 1727 he was
chosen as the colleague of Thomas Foxcroft (1697-1769) in the pastorate
of the First Church of Boston, continuing as pastor of this church until
his death. At the time of the "Great Awakening" of 1740-1743 and
afterwards, Chauncy was the leader of the so-called "Old Light" party in
New England, which strongly condemned the Whitefieldian revival as an
outbreak of emotional extravagance. His views were ably presented in his
sermon _Enthusiasm_ and in his _Seasonable Thoughts on the State of
Religion in New England_ (1743), written in answer to Jonathan Edwards's
_Some Thoughts Concerning the Present Revival of Religion in New
England_ (1742). He also took a leading part in opposition to the
projected establishment of an Anglican Episcopate in America, and before
and during the American War of Independence he ardently supported the
whig or patriot party. Theologically he has been classed as a precursor
of the New England Unitarians. He died in Boston on the 10th of February
1787. His publications include: _Compleat View of Episcopacy, as
Exhibited in the Fathers of the Christian Church, until the close of the
Second Century_ (1771); _Salvation of All Men, Illustrated and
Vindicated as a Scripture Doctrine_ (1782); _The Mystery Hid from Ages
and Generations made manifest by the Gospel-Revelation_ (1783); and
_Five Dissertations on the Fall and its Consequences_ (1785).

  See P.L. Ford's privately printed _Bibliotheca Chaunciana_ (Brooklyn,
  N.Y., 1884); and Williston Walker's _Ten New England Leaders_ (New
  York, 1901).



CHAUNY, a town of northern France in the department of Aisne, 19 m. S.
by W. of St Quentin by rail. Pop. (1906) 10,127. The town is situated on
the Oise (which here becomes navigable) and at the junction of the canal
of St Quentin with the lateral canal of the Oise, and carries on an
active trade. It contains mirror-polishing works, subsidiary to the
mirror-works of St Gobain, chemical works, sugar manufactories, metal
foundries and breweries. Chauny was the scene of much fighting in the
Hundred Years' War.



CHAUTAUQUA, a village on the west shore of Chautauqua Lake in the town
of Chautauqua, Chautauqua county, New York, U.S.A. Pop. of the town
(1900), 3590; (1905) 3505; (1910) 3515; of the village (1908) about 750.
The lake is a beautiful body of water over 1300 ft. above sea-level, 20
m. long, and from a few hundred yards to 3 m. in width. The town of
Chautauqua is situated near the north end and is within easy reach by
steamboat and electric car connexions with the main railways between the
east and the west. The town is known almost solely as being the
permanent home of the Chautauqua Institution, a system of popular
education founded in 1874 by Lewis Miller (1829-1899) of Akron, Ohio,
and Bishop John H. Vincent (b. 1832). The village, covering about three
hundred acres of land, is carefully laid out to provide for the work of
the Institution.

The Chautauqua Institution began as a Sunday-School Normal Institute,
and for nearly a quarter of a century the administration was in the
hands of Mr Miller, who was responsible for the business management, and
Bishop Vincent, who was head of the instruction department. Though
founded by Methodists, in its earliest years it became non-sectarian and
has furnished a meeting-ground for members of all sects and
denominations. At the very outset the activities of the assembly were
twofold: (1) the conducting of a summer school for Sunday-school
teachers, and (2) the presentation of a series of correlated lectures
and entertainments. Although the movement was and still is primarily
religious, it has always been assumed that the best religious education
must necessarily take advantage of the best that the educational world
can afford in the literatures, arts and sciences. The scope of the plan
rapidly broadened, and in 1879 a regular group of schools with graded
courses of study was established. At about the same time, also, the
Chautauqua Literary and Scientific Circle, providing a continuous
home-reading system, was founded. The season lasts during June, July and
August. In 1907 some 325 lectures, concerts, readings and entertainments
were presented by a group of over 190 lecturers, readers and musicians,
while at the same time 200 courses in the summer schools were offered by
a faculty of instructors drawn from the leading colleges and normal
schools of the country.

The Chautauqua movement has had an immense influence on education in the
United States, an influence which is especially marked in three
directions: (1) in the establishment of about 300 local assemblies or
"Chautauquas" in the United States patterned after the mother
Chautauqua; (2) in the promotion of the idea of summer education, which
has been followed by the founding of summer schools or sessions at a
large number of American universities, and of various special summer
schools, such as the Catholic Summer School of America, with
headquarters at Cliff Haven, Clinton county, New York, and the Jewish
Chautauqua Society, with headquarters at Buffalo, N.Y.; and (3) in the
establishment of numerous correspondence schools patterned in a general
way after the system provided by the Chautauqua Literary and Scientific
Circle.

  See John Heyl Vincent, _The Chautauqua Movement_ (Boston, 1886), and
  Frank C. Bray, _A Reading Journey through Chautauqua_ (Chicago, 1905).



CHAUVELIN, BERNARD FRANÇOIS, MARQUIS DE (1766-1832), French diplomatist
and administrator. Though master of the king's wardrobe in 1789, he
joined in the Revolution. He served in the army of Flanders, and then
was sent to London in February 1792, to induce England to remain neutral
in the war which was about to break out between France and "the king of
Bohemia and Hungary." He was well received at first, but after the 10th
of August 1792 he was no longer officially recognized at court, and on
the execution of Louis XVI. (21st of January 1793) he was given eight
days to leave England. After an unsuccessful embassy in Tuscany, he was
imprisoned as a suspect during the Terror, but freed after the 9th
Thermidor. Under Napoleon he became a member of the council of state,
and from 1812 to 1814 he governed Catalonia under the title of
intendant-general, being charged to win over the Catalonians to King
Joseph Bonaparte. He remained in private life during the Restoration and
the Hundred Days. In 1816 he was elected deputy, and spoke in favour of
liberty of the press and extension of the franchise. Though he was again
deputy in 1827 he played no part in public affairs, and resigned in
1829.

  See G. Pallain, _La Mission de Talleyrand à Londres en 1792_ (Paris,
  1889).



CHAUVIGNY, a town of western France, in the department of Vienne, 20 m.
E. of Poitiers by rail. Pop. (1906) 2326. The town is finely situated
overlooking the Vienne and a small torrent, and has two interesting
Romanesque churches, both restored in modern times. There are also ruins
of a château of the bishops of Poitiers, and of other strongholds. Near
Chauvigny is the curious bone-cavern of Jioux, the entrance to which is
fortified by large blocks of stone. The town carries on lime-burning and
plaster-manufacture, and there are stone quarries in the vicinity. Trade
is in wool and feathers.



CHAUVIN, ÉTIENNE (1640-1725), French Protestant divine, was born at
Nîmes on the 18th of April 1640. At the revocation of the Edict of
Nantes he retired to Rotterdam, where he was for some years preacher at
the Walloon church; in 1695 the elector of Brandenburg appointed him
pastor and professor of philosophy, and later inspector of the French
college at Berlin, where he enjoyed considerable reputation as a
representative of Cartesianism and as a student of physics. His
principal work is a laborious _Lexicon Rationale, sive Thesaurus
Philosophicus_ (Rotterdam, 1692; new and enlarged edition, Leuwarden,
1713). He also wrote _Theses de Cognitione Dei_ (1662), and started the
_Nouveau Journal des Savans_ (1694-1698).

  See E. and E. Haag, _La France Protestante_, vol. iv. (1884).



CHAUVINISM, a term for unreasonable and exaggerated patriotism, the
French equivalent of "Jingoism." The word originally signified idolatry
of Napoleon, being taken from a much-wounded veteran, Nicholas Chauvin,
who, by his adoration of the emperor, became the type of blind
enthusiasm for national military glory.



CHAUX DE FONDS, LA, a large industrial town in the Swiss canton of
Neuchâtel. It is about 19 m. by rail N. W. of Neuchâtel, and stands at a
height of about 3255 ft. in a valley (5 m. long) of the same name in the
Jura. Pop. (1900) 35,968 (only 13,659 in 1850); (1905) 38,700, mainly
French-speaking and Protestants; of the 6114 "Catholics" the majority
are "Old Catholics." It is a centre of the watch-making industry,
especially of gold watch cases; about 70% of those manufactured in
Switzerland are turned out here. In 1900 it exported watches to the
value of nearly £3,000,000 sterling. There is a school of industrial art
(engraving and enamelling watch cases) and a school of watch-making
(including instruction in the manufacture of chronometers and other
scientific instruments of precision). It boasts of being _le plus gros
village de l'Europe_, and certainly has preserved some of the features
of a big village. Léopold Robert (1794-1835), the painter, was born
here.    (W. A. B. C.).



CHAVES, a town of northern Portugal, in the district of Villa Real,
formerly included in the province of Traz os Montes; 8 m. S. of the
Spanish frontier, on the right bank of the river Tamega. Pop. (1900)
6388. Chaves is the ancient _Aquae Flaviae_, famous for its hot saline
springs, which are still in use. A fine Roman bridge of 18 arches spans
the Tamega. In the 16th century Chaves contained 20,000 inhabitants; it
was long one of the principal frontier fortresses, and in fact derives
its present name from the position which makes it the "keys," or
_chaves_, of the north. One of its churches contains the tomb of
Alphonso I. of Portugal (1139-1185). In 1830 the town gave the title of
marquess to Pinto da Fonseca, a leader of the Miguelite party.



CHAZELLES, JEAN MATHIEU DE (1657-1710), French hydrographer, was born at
Lyons on the 24th of July 1657. He was nominated professor of
hydrography at Marseilles in 1685, and in that capacity carried out
various coast surveys. In 1693 he was engaged to publish a second volume
of the _Neptune français_, which was to include the hydrography of the
Mediterranean. For this purpose he visited the Levant and Egypt. When in
Egypt he measured the pyramids, and, finding that the angles formed by
the sides of the largest were in the direction of the four cardinal
points, he concluded that this position must have been intended, and
also that the poles of the earth and meridians had not deviated since
the erection of those structures. He was made a member of the Academy in
1695, and died in Paris on the 16th of January 1710.



CHEADLE, a town in the Altrincham parliamentary division of Cheshire,
England, 6 m. S. of Manchester, included in the urban district of
Cheadle and Gatley. Pop. (1901) 7916. This is one of the numerous
townships of modern growth which fringe the southern boundaries of
Manchester, and practically form suburbs of that city. Stockport lies
immediately to the east. The name occurs in the formerly separate
villages of Cheadle Hulme, Cheadle Bulkeley and Cheadle Moseley. There
are cotton printing and bleaching works in the locality. The parish
church of St Giles, Cheadle, is Perpendicular, containing an altar-tomb
of the 15th century for two knights.



CHEADLE, a market town in the Leek parliamentary division of
Staffordshire, England, 13 m. N.E. of Stafford, and the terminus of a
branch line from Cresswell on the North Staffordshire railway. Pop.
(1901) 5186. The Roman Catholic church of St Giles, with a lofty spire,
was designed by Pugin and erected in 1846. The interior is lavishly
decorated. There are considerable collieries in the neighbourhood, and
silk and tape works in the town. In the neighbouring Froghall district
limestone is quarried, and there are manufactures of copper. In Cheadle
two fairs of ancient origin are held annually.



CHEATING, "the fraudulently obtaining the property of another by any
deceitful practice not amounting to felony, which practice is of such a
nature that it directly affects, or may directly affect, the public at
large" (Stephen, _Digest of Criminal Law_, chap. xl. §367). Cheating is
either a common law or statutory offence, and is punishable as a
misdemeanour. An indictment for cheating at common law is of
comparatively rare occurrence, and the statutory crime usually presents
itself in the form of obtaining money by false pretences (q.v.). The
word "cheat" is a variant of "_escheat_," i.e. the reversion of land to
a lord of the fee through the failure of blood of the tenant. The
shortened form "cheater" for "escheator" is found early in the legal
sense, and _chetynge_ appears in the _Promptorium Parvulorum_, c. 1440,
as the equivalent of _confiscatio_. In the 16th century "cheat" occurs
in vocabularies of thieves and other slang, and in such works as the
_Use of Dice-Play_ (1532). It is frequent in Thomas Harman's _Caveat_ or
_Warening for ... Vagabones_ (1567), in the sense of "thing," with a
descriptive word attached, e.g. _smeling chete_ = nose. In the tract
_Mihil Mumchance, his Discoverie of the Art of Cheating_, doubtfully
attributed to Robert Greene (1560-1592), we find that gamesters call
themselves _cheaters_, "borrowing the term from the lawyers." The sense
development is obscure, but it would seem to be due to the extortionate
or fraudulent demands made by legal "escheators."



CHEBICHEV, PAFNUTIY LVOVICH (1821-1894), Russian mathematician, was born
at Borovsk on the 26th of May 1821. He was educated at the university of
Moscow, and in 1859 became professor of mathematics in the university of
St Petersburg, a position from which he retired in 1880. He was chosen a
correspondent of the Institute of France in 1860, and succeeded to the
high honour of _associé étranger_ in 1874. He was also a foreign member
of the Royal Society of London. After N.I. Lobachevskiy he probably
ranks as the most distinguished mathematician Russia has produced. In
1841 he published a valuable paper, "Sur la convergence de la serié de
Taylor," in _Crelle's Journal_. His best-known papers, however, deal
with prime numbers; in one of these ("Sur les nombres premiers," 1850)
he established the existence of limits within which must be comprised
the sum of the logarithms of the primes inferior to a given number.
Another question to which he devoted much attention was that of
obtaining rectilinear motion by linkage. The parallel motion known by
his name is a three-bar linkage, which gives a very close approximation
to exact rectilinear motion, but in spite of all his efforts he failed
to devise one that produced absolutely true rectilinear motion. At last,
indeed, he came to the conclusion that to do so was impossible, and in
that conviction set to work to find a rigorous proof of the
impossibility. While he was engaged on this task the desired linkage,
which moved the highest admiration of J.J. Sylvester, was discovered and
exhibited to him by one of his pupils, named Lipkin, who, however, it
was afterwards found, had been anticipated by A. Peaucellier. Chebichev
further constructed an instrument for drawing large circles, and an
arithmetical machine with continuous motion. His mathematical writings,
which account for some forty entries in the Royal Society's catalogue of
scientific papers, cover a wide range of subjects, such as the theory of
probabilities, quadratic forms, theory of integrals, gearings, the
construction of geographical maps, &c. He also published a _Traité de la
théorie des nombres_. He died at St Petersburg on the 8th of December
1894.



CHEBOYGAN, a city and the county-seat of Cheboygan county, Michigan,
U.S.A., on South Channel (between Lakes Michigan and Huron), at the
mouth of Cheboygan river, in the N. part of the lower peninsula. Pop.
(1890) 6235; (1900) 6489, of whom 2101 were foreign-born; (1904) 6730;
(1910) 6859. It is served by the Michigan Central and the Detroit &
Mackinac railways, and by steamboat lines to Chicago, Milwaukee,
Detroit, Sault Ste Marie, Green Bay and other lake ports; and is
connected by ferry with Mackinac and Pointe aux Pins. During a great
part of the year small boats ply between Cheboygan and the head of
Crooked Lake, over the "Inland Route." Cheboygan is situated in a
fertile farming region, for which it is a trade centre, and it has
lumber mills, tanneries, paper mills, boiler works, and other
manufacturing establishments. The water-works are owned and operated by
the municipality. The city, at first called Duncan, then Inverness, and
finally Cheboygan, was settled in 1846, incorporated as a village in
1871, reincorporated in 1877, and chartered as a city in 1889.



CHECHENZES, TCHETCHEN, or KHISTS (_Kisti_), the last being the name by
which they are known to the Georgians, a people of the eastern Caucasus
occupying the whole of west Daghestan. They call themselves Nakhtche,
"people." A wild, fierce people, they fought desperately against Russian
aggression in the 18th century under Daûd Beg and Oman Khan and Shamyl,
and in the 19th under Khazi-Mollah, and even now some are independent in
the mountain districts. On the surrender of the chieftain Shamyl to
Russia in 1859 numbers of them migrated into Armenia. In physique the
Chechenzes resemble the Circassians, and have the same haughtiness of
carriage. They are of a generous temperament, very hospitable, but quick
to revenge. They are fond of fine clothes, the women wearing rich robes
with wide, pink silk trousers, silver bracelets and yellow sandals.
Their houses, however, are mere hovels, some dug out of the ground,
others formed of boughs and stones. Before their subjection to Russia
they were remarkable for their independence of spirit and love of
freedom. Everybody was equal, and they had no slaves except prisoners of
war. Government in each commune was by popular assembly, and the
administration of justice was in the hands of the wronged. Murder and
robbery with violence could be expiated only by death, unless the
criminal allowed his hair to grow and the injured man consented to shave
it himself and take an oath of brotherhood on the Koran. Otherwise the
law of vendetta was fully carried out with curious details. The wronged
man, wrapped in a white woollen shroud, and carrying a coin to serve as
payment to a priest for saying the prayers for the dead, started out in
search of his enemy. When the offender was found he must fight to a
finish. A remarkable custom among one tribe is that if a betrothed man
or woman dies on the eve of her wedding, the marriage ceremony is still
performed, the dead being formally united to the living before
witnesses, the father, in case it is the girl who dies, never failing to
pay her dowry. The religion of the Chechenzes is Mahommedanism, mixed,
however, with Christian doctrines and observances. Three churches near
Kistin in honour of St George and the Virgin are visited as places of
pilgrimage, and rams are there offered as sacrifices. The Chechenzes
number upwards of 200,000. They speak a distinct language, of which
there are said to be twenty separate dialects.

  See Ernest Chanter, _Recherches anthropologiques dans le Caucase_
  (Lyon, 1885-1887); D.G. Brinton, _Races of Man_ (1890); Hutchinson,
  _Living Races of Mankind_ (London, 1901).



CHECKERS, the name by which the game of draughts (q.v.) is known in
America. The origin of the name is the same as that of "chess" (q.v.).



CHEDDAR, a small town in the Wells parliamentary division of
Somersetshire, England, 22 m. S.W. of Bristol by a branch of the Great
Western railway. Pop. (1901) 1975. The town, with its Perpendicular
church and its picturesque market-cross, lies below the south-western
face of the Mendip Hills, which rise sharply from 600 to 800 ft. To the
west stretches the valley of the river Axe, broad, low and flat. A fine
gorge opening from the hills immediately upon the site of the town is
known as Cheddar cliffs from the sheer walls which flank it; the
contrast of its rocks and rich vegetation, and the falls of a small
stream traversing it, make up a beautiful scene admired by many
visitors. Several stalactitical caverns are also seen, and prehistoric
British and Roman relics discovered in and near them are preserved in a
small museum. The two caverns most frequently visited are called
respectively Cox's and Gough's; in each, but especially in the first,
there is a remarkable collection of fantastic and beautiful
stalactitical forms. There are other caverns of greater extent but less
beauty, but their extent is not completely explored. The remains
discovered in the caves give evidence of British and Roman settlements
at Cheddar (_Cedre_, _Chedare_), which was a convenient trade centre.
The manor of Cheddar was a royal demesne in Saxon times, and the
witenagemot was held there in 966 and 968. It was granted by John in
1204 to Hugh, archdeacon of Wells, who sold it to the bishop of Bath and
Wells in 1229, whose successors were overlords until 1553, when the
bishop granted it to the king. It is now owned by the marquis of Bath.
By a charter of 1231 extensive liberties in the manor of Cheddar were
granted to Bishop Joceline, who by a charter of 1235 obtained the right
to hold a weekly market and fair. By a charter of Edward III. (1337)
Cheddar was removed from the king's forest of Mendip. The market was
discontinued about 1690. Fairs are now held on the 4th of May and the
29th of October under the original grants. The name of Cheddar is given
to a well-known species of cheese (see DAIRY), the manufacture of which
began in the 17th century in the town and neighbourhood.



CHEDUBA, or MAN-AUNG, an island in the Bay of Bengal, situated 10 m.
from the coast of Arakan, between 18° 40' and 18° 56' N. lat., and
between 93° 31' and 93° 50' E. long. It forms part of the Kyaukpyu
district of Arakan. It extends about 20 m. in length from N. to S., and
17 m. from E. to W., and its area of 220 sq. m. supports a population of
26,899 (in 1901). The channel between the island and the mainland is
navigable for boats, but not for large vessels. The surface of the
interior is richly diversified by hill and dale, and in the southern
portion some of the heights exceed a thousand feet in elevation. There
are various indications of former volcanic activity, and along the coast
are earthy cones covered with green-sward, from which issue springs of
muddy water emitting bubbles of gas. Copper, iron and silver ore have
been discovered; but the island is chiefly noted for its petroleum
wells, the oil derived from which is of excellent quality, and is
extensively used in the composition of paint, as it preserves wood from
the ravages of insects. Timber is not abundant, but the gamboge tree and
the wood-oil tree are found of a good size. Tobacco, cotton, sugar-cane,
hemp and indigo are grown, and the staple article is rice, which is of
superior quality, and the chief article of export. The inhabitants of
the island are mainly Maghs. Cheduba fell to the Burmese in the latter
part of the 18th century. From them it was captured in 1824 by the
British, whose possession of it was confirmed in 1826 by the treaty
concluded with the Burmese at Yandaboo.



CHEERING, the uttering or making of sounds encouraging, stimulating or
exciting to action, indicating approval of acclaiming or welcoming
persons, announcements of events and the like. The word "cheer" meant
originally face, countenance, expression, and came through the O. Fr.
into Mid. Eng. in the 13th century from the Low Lat. _cara_, head; this
is generally referred to the Gr. [Greek: kara]. _Cara_ is used by the
6th-century poet Flavius Cresconius Corippus, "Postquam venere verendam
Caesaris ante caram" (_In Laudem Justini Minoris_). "Cheer" was at first
qualified with epithets, both of joy and gladness and of sorrow; compare
"She thanked Dyomede for alle ... his gode chere" (Chaucer, _Troylus_)
with "If they sing ... 'tis with so dull a cheere" (Shakespeare,
_Sonnets_, xcvii.). An early transference in meaning was to hospitality
or entertainment, and hence to food and drink, "good cheer." The sense
of a shout of encouragement or applause is a late use. Defoe (_Captain
Singleton_) speaks of it as a sailor's word, and the meaning does not
appear in Johnson. Of the different words or rather sounds that are used
in cheering, "hurrah," though now generally looked on as the typical
British form of cheer, is found in various forms in German,
Scandinavian, Russian (_urá_), French (_houra_). It is probably
onomatopoeic in origin; some connect it with such words as "hurry,"
"whirl"; the meaning would then be "haste," to encourage speed or onset
in battle. The English "hurrah" was preceded by "huzza," stated to be a
sailor's word, and generally connected with "heeze," to hoist, probably
being one of the cries that sailors use when hauling or hoisting. The
German _hoch_, seen in full in _hoch lebe der Kaiser_, &c., the French
_vive_, Italian and Spanish _viva_, _evviva_, are cries rather of
acclamation than encouragement. The Japanese shout _banzai_ became
familiar during the Russo-Japanese War. In reports of parliamentary and
other debates the insertion of "cheers" at any point in a speech
indicates that approval was shown by members of the House by emphatic
utterances of "hear hear." Cheering may be tumultuous, or it may be
conducted rhythmically by prearrangement, as in the case of the
"Hip-hip-hip" by way of introduction to a simultaneous "hurrah."

Rhythmical cheering has been developed to its greatest extent in America
in the college yells, which may be regarded as a development of the
primitive war-cry; this custom has no real analogue at English schools
and universities, but the New Zealand football team in 1907 familiarized
English crowds at their matches with a similar sort of war-cry adopted
from the Maoris. In American schools and colleges there is usually one
cheer for the institution as a whole and others for the different
classes. The oldest and simplest are those of the New England colleges.
The original yells of Harvard and Yale are identical in form, being
composed of _rah_ (abbreviation of _hurrah_) nine times repeated,
shouted in unison with the name of the university at the end. The Yale
cheer is given faster than that of Harvard. Many institutions have
several different yells, a favourite variation being the name of the
college shouted nine times in a slow and prolonged manner. The best
known of these variants is the Yale cheer, partly taken from the _Frogs_
of Aristophanes, which runs thus:

  "Brekekekéx, ko-áx, ko-áx,
   Brekekekéx, ko-áx, ko-áx,
   O-óp, O-óp, parabalo[=u],
   Yale, Yale, Yale,
   Rah, rah, rah, rah, rah, rah, rah, rah, rah,
   Yale! Yale! Yale!"

The regular cheer of Princeton is:

  "H'ray, h'ray, h'ray, tiger,
   Siss, boom, ah; Princeton!"

This is expanded into the "triple cheer":

  "H'ray, h'ray, h'ray,
   Tiger, tiger, tiger,
   Siss, siss, siss,
   Boom, boom, boom,
   Ah, ah, ah,
   Princetón, Princetón, Princetón!"

The "railroad cheer" is like the foregoing, but begun very slowly and
broadly, and gradually accelerated to the end, which is enunciated as
fast as possible. Many cheers are formed like that of Toronto
University:

  "Varsitý, varsitý,
   V-a-r-s-í-t-y (spelled)
   VARSIT-Y (spelled _staccato_)
   Vár-sí-tý,
   Rah, rah, rah!"

Another variety of yell is illustrated by that of the School of
Practical Science of Toronto University:

  "Who are we? Can't you guess?
   We are from the S.P.S.!"

The cheer of the United States Naval Academy is an imitation of a
nautical syren. The Amherst cheer is:

  "Amherst! Amherst! Amherst! Rah! Rah!
   Amherst! Rah! Rah!
   Rah! Rah! Rah! Rah! Rah! Rah! Amherst!"

Besides the cheers of individual institutions there are some common to
all, generally used to compliment some successful athlete or popular
professor. One of the oldest examples of these personal cheers is:

  "Who was George Washington?
   First in war,
   First in peace,
   Fírst in the heárts of his countrymén,"

followed by a stamping on the floor in the same rhythm.

College yells are used particularly at athletic contests. In any large
college there are several leaders, chosen by the students, who stand in
front and call for the different songs and cheers, directing with their
arms in the fashion of an orchestral conductor. This cheering and
singing form one of the distinctive features of inter-collegiate and
scholastic athletic contests in America.



CHEESE (Lat. _caseus_), a solidified preparation from milk, the
essential constituent of which is the proteinous or nitrogenous
substance _casein_. All cheese contains in addition some proportion of
fatty matter or butter, and in the more valuable varieties the butter
present is often greater in amount than the casein. Cheese being thus a
compound substance of no definite composition is found in commerce of
many different varieties and qualities; and such qualities are generally
recognized by the names of the localities in which they are
manufactured. The principal distinctions arise from differences in the
composition and condition of the milk operated upon, from variations in
the method of preparation and curing, and from the use of the milk of
other animals besides the cow, as, for example, the goat and the ewe,
from the milk of both of which cheese is manufactured on a commercial
scale. For details about different cheeses and cheese-making, see DAIRY.
From the Urdu _chiz_ ("thing") comes the slang expression "the cheese,"
meaning "the perfect thing," apparently from Anglo-Indian usage.

  A useful summary of the history and manufacture of all sorts of
  cheeses, under their different names, is given in Bulletin 105 of the
  Bureau of Animal Industry (United States Dep. of Agriculture),
  _Varieties of Cheese_, by C.F. Doane and H.W. Lawson (Washington,
  1908).



CHEESE CLOTH, the name given to cloth, usually made from flax or tow
yarns, of an open character, resembling a fine riddle or sieve, used for
wrapping cheese. A finer quality and texture is made for women's gowns.
A similar cloth is used for inside linings in the upholstery trade, and
for the ground of embroidery.



CHEETA (CHITA), or HUNTING-LEOPARD (_Cynaelurus jubatus_, formerly known
as _Gueparda jubata_), a member of the family _Felidae_, distinguished
by its claws being only partially retractile (see CARNIVORA). The cheeta
attains a length of 3 to 4 ft.; it is of a pale fulvous colour, marked
with numerous spots of black on the upper surface and sides, and is
nearly white beneath. The fur is somewhat crisp, altogether lacking the
sleekness which characterizes the fur of the typical cats, and the tail
is long and somewhat bushy at the extremity. In confinement the cheeta
soon becomes fond of those who are kind to it, and gives evidence of its
attachment in an open, dog-like manner. The cheeta is found throughout
Africa and southern Asia, and has been employed for centuries in India
and Persia in hunting antelopes and other game. According to Sir W.
Jones, this mode of hunting originated with Hushing, king of Persia, 865
B.C., and afterwards became so popular that certain of the Mongol
emperors were in the habit of being accompanied in their sporting
expeditions by a thousand hunting leopards. In prosecuting this sport at
the present day the cheeta is conveyed to the field in a low car without
sides, hooded and chained like hunting-birds in Europe in the days of
falconry. When a herd of deer or antelopes is seen, the car, which bears
a close resemblance to the ordinary vehicles used by the peasants, is
usually brought within 200 yds. of the game before the latter takes
alarm; the cheeta is then let loose and the hood removed from its eyes.
No sooner does it see the herd, than dropping from the car on the side
remote from its prey, it approaches stealthily, making use of whatever
means of concealment the nature of the ground permits, until observed,
when making a few gigantic bounds, it generally arrives in the midst of
the herd and brings down its victim with a stroke of its paw. The
sportsman then approaches, draws off a bowl of the victim's blood, and
puts it before the cheeta, which is again hooded and led back to the
car. Should it not succeed in reaching the herd in the first few bounds,
it makes no further effort to pursue, but retires seemingly dispirited
to the car. In Africa the cheeta is only valued for its skin, which is
worn by chiefs and other people of rank. It should be added that in
India the name cheeta (chita) is applied also to the leopard.



CHEFFONIER, properly CHIFFONIER, a piece of furniture differentiated
from the sideboard by its smaller size and by the enclosure of the
whole of the front by doors. Its name (which comes from the French for a
rag-gatherer) suggests that it was originally intended as a receptacle
for odds and ends which had no place elsewhere, but it now usually
serves the purpose of a sideboard. It is a remote and illegitimate
descendant of the cabinet; it has rarely been elegant and never
beautiful. It was one of the many curious developments of the mixed
taste, at once cumbrous and bizarre, which prevailed in furniture during
the Empire period in England. The earliest cheffoniers date from that
time; they are usually of rosewood--the favourite timber of that moment;
their "furniture" (the technical name for knobs, handles and
escutcheons) was most commonly of brass, and there was very often a
raised shelf with a pierced brass gallery at the back. The doors were
well panelled and often edged with brass-beading, while the feet were
pads or claws, or, in the choicer examples, sphinxes in gilded bronze.
Cheffoniers are still made in England in cheap forms and in great
number.



CHEH-KIANG, an eastern province of China, bounded N. by the province of
Kiang-su, E. by the sea, S. by the province of Fu-kien, and W. by the
provinces of Kiang-si and Ngan-hui. It occupies an area of about 36,000
sq. m., and contains a population of 11,800,000. With the exception of a
small portion of the great delta plain, which extends across the
frontier from the province of Kiang-su, and in which are situated the
famous cities of Hu Chow, Ka-hing, Hang-chow, Shao-Sing and Ning-po, the
province forms a portion of the Nan-shan of south-eastern China, and is
hilly throughout. The Nan-shan ranges run through the centre of the
province from south-west to north-east, and divide it into a northern
portion, the greater part of which is drained by the Tsien-t'ang-kiang,
and a southern portion which is chiefly occupied by the Ta-chi basin.
The valleys enclosed between the mountain ranges are numerous, fertile,
and for the most part of exquisite beauty. The hilly portion of the
province furnishes large supplies of tea, and in the plain which extends
along the coast, north of Ning-po, a great quantity of silk is produced.
In minerals the province is poor. Coal and iron are occasionally met
with, and traces of copper ore are to be found in places, but none of
these minerals exists in sufficiently large deposits to make mining
remunerative. The province, however, produces cotton, rice, ground-nuts,
wheat, indigo, tallow and beans in abundance. The principal cities are
Hang-chow, which is famed for the beauty of its surroundings, Ning-po,
which has been frequented by foreign ships ever since the Portuguese
visited it in the 16th century, and Wênchow. Opposite Ning-po, at a
distance of about 50 m., lies the island of Chusan, the largest of a
group bearing that general name. This island is 21 m. long, and about 50
m. in circumference. It is very mountainous, and is surrounded by
numerous islands and islets. On its south side stands the walled town of
Ting-hai, in front of which is the principal harbour. The population is
returned as 50,000.



CHEKE, SIR JOHN (1514-1557), English classical scholar, was the son of
Peter Cheke, esquire-bedell of Cambridge University. He was educated at
St John's College, Cambridge, where he became a fellow in 1529. While
there he adopted the principles of the Reformation. His learning gained
him an exhibition from the king, and in 1540, on Henry VIII.'s
foundation of the regius professorships, he was elected to the chair of
Greek. Amongst his pupils at St John's were Lord Burghley, who married
Cheke's sister Mary, and Roger Ascham, who in _The Schoolmaster_ gives
Cheke the highest praise for scholarship and character. Together with
Sir Thomas Smith, he introduced a new method of Greek pronunciation very
similar to that commonly used in England in the 19th century. It was
strenuously opposed in the University, where the continental method
prevailed, and Bishop Gardiner, as chancellor, issued a decree against
it (June 1542); but Cheke ultimately triumphed. On the 10th of July
1554, he was chosen as tutor to Prince Edward, and after his pupil's
accession to the throne he continued his instructions. Cheke took a
fairly active share in public life; he sat, as member for Bletchingley,
for the parliaments of 1547 and 1552-1553; he was made provost of King's
College, Cambridge (April 1, 1548), was one of the commissioners for
visiting that university as well as Oxford and Eton, and was appointed
with seven divines to draw up a body of laws for the governance of the
church. On the 11th of October 1551 he was knighted; in 1553 he was made
one of the secretaries of state, and sworn of the privy council. His
zeal for Protestantism induced him to follow the duke of Northumberland,
and he filled the office of secretary of state for Lady Jane Grey during
her nine days' reign. In consequence Mary threw him into the Tower (July
27, 1553), and confiscated his wealth. He was, however, released on the
13th of September 1554, and granted permission to travel abroad. He went
first to Basel, then visited Italy, giving lectures in Greek at Padua,
and finally settled at Strassburg, teaching Greek for his living. In the
spring of 1556 he visited Brussels to see his wife; on his way back,
between Brussels and Antwerp, he and Sir Peter Carew were treacherously
seized (May 15) by order of Philip of Spain, hurried over to England,
and imprisoned in the Tower. Cheke was visited by two priests and by Dr
John Feckenham, dean of St Paul's, whom he had formerly tried to convert
to Protestantism, and, terrified by a threat of the stake, he gave way
and was received into the Church of Rome by Cardinal Pole, being cruelly
forced to make two public recantations. Overcome with shame, he did not
long survive, but died in London on the 13th of September 1557,
carrying, as T. Fuller says (_Church History_), "God's pardon and all
good men's pity along with him." About 1547 Cheke married Mary, daughter
of Richard Hill, sergeant of the wine-cellar to Henry VIII., and by her
he had three sons. The descendants of one of these, Henry, known only
for his translation of an Italian morality play _Freewyl_ (_Tragedio del
Libero Arbitrio_) by Nigri de Bassano, settled at Pyrgo in Essex.

  Thomas Wilson, in the epistle prefixed to his translation of the
  Olynthiacs of Demosthenes (1570), has a long and most interesting
  eulogy of Cheke; and Thomas Nash, in _To the Gentlemen Students_,
  prefixed to Robert Greene's _Menaphon_ (1589), calls him "the
  Exchequer of eloquence, Sir Ihon Cheke, a man of men, supernaturally
  traded in all tongues." Many of Cheke's works are still in MS., some
  have been altogether lost. One of the most interesting from a
  historical point of view is the _Hurt of Sedition how greueous it is
  to a Communewelth_ (1549), written on the occasion of Ket's rebellion,
  republished in 1569, 1576 and 1641, on the last occasion with a life
  of the author by Gerard Langbaine. Others are _D. Joannis Chrysostomi
  homiliae duae_ (1543), _D. Joannis Chrysostomi de providentia Dei_
  (1545), _The Gospel according to St Matthew ... translated_ (c. 1550;
  ed. James Goodwin, 1843), _De obitu Martini Buceri_ (1551), (Leo
  VI.'s) _de Apparatu bellico_ (Basel, 1554; but dedicated to Henry
  VIII., 1544), _Carmen Heroicum, aut epitaphium in Antonium Deneium_
  (1551), _De pronuntiatione Graecae ... linguae_ (Basel, 1555). He also
  translated several Greek works, and lectured admirably upon
  Demosthenes.

  His _Life_ was written by John Strype (1821); additions by J. Gough
  Nichols in _Archaeologia_ (1860), xxxviii. 98, 127.



CHELLIAN, the name given by the French anthropologist G. de Mortillet to
the first epoch of the Quaternary period when the earliest human remains
are discoverable. The word is derived from the French town Chelles in
the department of Seine-et-Marne. The climate of the Chellian epoch was
warm and humid as evidenced by the wild growth of fig-trees and laurels.
The animals characteristic of the epoch are the _Elephas antiquus_, the
rhinoceros, the cave-bear, the hippopotamus and the striped hyaena. Man
existed and belonged to the Neanderthal type. The implements
characteristic of the period are flints chipped into leaf-shaped forms
and held in the hand when used. The drift-beds of St Acheul (Amiens), of
Menchecourt (Abbeville), of Hoxne (Suffolk), and the detrital laterite
of Madras are considered by de Mortillet to be synchronous with the
Chellian beds.

  See Gabriel de Mortillet, _Le Préhistorique_ (1900); Lord Avebury,
  _Prehistoric Times_ (1900).



CHELMSFORD, FREDERIC THESIGER, 1ST BARON (1794-1878), lord chancellor of
England, was the third son of Charles Thesiger, and was born in London
on the 15th of April 1794. His father, collector of customs at St
Vincent's, was the son of a Saxon gentleman who had migrated to England
and become secretary to Lord Rockingham, and was the brother of Sir
Frederic Thesiger, naval A.D.C. to Nelson at Copenhagen. Young Frederic
Thesiger was originally destined for a naval career, and he served as a
midshipman on board the "Cambrian" frigate in 1807 at the second
bombardment of Copenhagen. His only surviving brother, however, died
about this time, and he became entitled to succeed to a valuable estate
in the West Indies, so it was decided that he should leave the navy and
study law, with a view to practising in the West Indies and eventually
managing his property in person. Another change of fortune, however,
awaited him, for a volcano destroyed the family estate, and he was
thrown back upon his prospect of a legal practice in the West Indies. He
proceeded to enter at Gray's Inn in 1813, and was called on the 18th of
November 1818, another change in his prospects being brought about by
the strong advice of Godfrey Sykes, a special pleader in whose chambers
he had been a pupil, that he should remain to try his fortune in
England. He accordingly joined the home circuit, and soon got into good
practice at the Surrey sessions, while he also made a fortunate purchase
in buying the right to appear in the old palace court (see LORD
STEWARD). In 1824 he distinguished himself by his defence of Joseph Hunt
when on his trial at Hertford with John Thurtell for the murder of Wm.
Weare; and eight years later at Chelmsford assizes he won a hard-fought
action in an ejectment case after three trials, to which he attributed
so much of his subsequent success that when he was raised to the peerage
he assumed the title Lord Chelmsford. In 1834 he was made king's
counsel, and in 1835 was briefed in the Dublin election inquiry which
unseated Daniel O'Connell. In 1840 he was elected M.P. for Woodstock. In
1844 he became solicitor-general, but having ceased to enjoy the favour
of the duke of Marlborough, lost his seat for Woodstock and had to find
another at Abingdon. In 1845 he became attorney-general, holding the
post until the fall of the Peel administration on the 3rd of July 1846.
Thus by three days Thesiger missed being chief justice of the common
pleas, for on the 6th of July Sir Nicholas Tindal died, and the seat on
the bench, which would have been Thesiger's as of right, fell to the
Liberal attorney-general, Sir Thomas Wilde. Sir Frederic Thesiger
remained in parliament, changing his seat, however, again in 1852, and
becoming member for Stamford. During this period he enjoyed a very large
practice at the bar, being employed in many _causes célèbres_. On Lord
Derby coming into office for the second time in 1858, Sir Frederic
Thesiger was raised straight from the bar to the lord chancellorship (as
were Lord Brougham, Lord Selborne and Lord Halsbury). In the following
year Lord Derby resigned and his cabinet was broken up. Again in 1866,
on Lord Derby coming into office for the third time, Lord Chelmsford
became lord chancellor for a short period. In 1868 Lord Derby retired,
and Disraeli, who took his place as prime minister, wished for Lord
Cairns as lord chancellor. Lord Chelmsford was very sore at his
supersession and the manner of it, but, according to Lord Malmesbury he
retired under a compact made before he took office. Ten years later Lord
Chelmsford died in London on the 5th of October 1878. Lord Chelmsford
had married in 1822 Anna Maria Tinling. He left four sons and three
daughters, of whom the eldest, Frederick Augustus, 2nd Baron Chelmsford
(1827-1905), earned distinction as a soldier, while the third, Alfred
Henry Thesiger (1838-1880) was made a lord justice of appeal and a privy
councillor in 1877, at the early age of thirty-nine, but died only three
years later.

  See _Lives of the Chancellors_ (1908), by J.B. Atlay, who has had the
  advantage of access to an unpublished autobiography of Lord
  Chelmsford's.



CHELMSFORD, a market town and municipal borough, and the county town of
Essex, England, in the Chelmsford parliamentary division, 30 m. E.N.E.
from London by the Great Eastern railway. Pop. (1901) 12,580. It is
situated in the valley of the Chelmer, at the confluence of the Cann,
and has communication by the river with Maldon and the Blackwater
estuary 11 m. east. Besides the parish church of St Mary, a graceful
Perpendicular edifice, largely rebuilt, the town has a grammar school
founded by Edward VI., an endowed charity school and a museum. It is the
seat of the county assizes and quarter sessions, and has a handsome
shire hall; the county gaol is near the town. Its corn and cattle
markets are among the largest in the county; for the first a fine
exchange is provided. In the centre of the square in which the corn
exchange is situated stands a bronze statue of Lord Chief-Justice Tindal
(1776-1846), a native of the parish. There are agricultural implement
and iron foundries, large electric light and engineering works,
breweries, tanneries, maltings and extensive corn mills. There is a
race-course 2 m. south of the town. The borough is under a mayor, 6
aldermen and 18 councillors. Area 2308 acres.

A place of settlement since Palaeolithic times, Chelmsford
(_Chilmersford, Chelmeresford, Chelmesford_) owed its importance to its
position on the road from London to Colchester. It consisted of two
manors: that of Moulsham, which remained in the possession of
Westminster Abbey from Saxon times till the reign of Henry VIII., when
it was granted to Thomas Mildmay; and that of Bishop's Hall, which was
held by the bishops of London from the reign of Edward the Confessor to
1545, when it passed to the crown and was granted to Thomas Mildmay in
1563. The medieval history of Chelmsford centred round the manor of
Bishop's Hall. Early in the 12th century Bishop Maurice built the bridge
over the Chelmer which brought the road from London directly through the
town, thus making it an important stopping-place. The town was not
incorporated until 1888. In 1225 Chelmsford was made the centre for the
collection of fifteenths from the county of Essex, and in 1227 it became
the regular seat of assizes and quarter-sessions. Edward I. confirmed
Bishop Richard de Gravesend in his rights of frank pledge in Chelmsford
in 1290, and in 1395 Richard II. granted the return of writs to Bishop
Robert de Braybroke. In 1377 writs were issued for the return of
representatives from Chelmsford to parliament, but no return of members
has been found. In 1199 the bishop obtained the grant of a weekly market
at the yearly rent of one palfrey, and in 1201 that of an annual fair,
now discontinued, for four days from the feast of St Philip and St
James.



CHELSEA, a western metropolitan borough of London, England, bounded E.
by the city of Westminster, N.W. by Kensington, S.W. by Fulham, and S.
by the river Thames. Pop. (1901) 73,842. Its chief thoroughfare is
Sloane Street, containing handsome houses and good shops, running south
from Knightsbridge to Sloane Square. Hence King's Road leads west, a
wholly commercial highway, named in honour of Charles II., and recalling
the king's private road from St James's Palace to Fulham, which was
maintained until the reign of George IV. The main roads south
communicate with the Victoria or Chelsea, Albert and Battersea bridges
over the Thames. The beautiful Chelsea embankment, planted with trees
and lined with fine houses and, in part, with public gardens, stretches
between Victoria and Battersea bridges. The better residential portion
of Chelsea is the eastern, near Sloane Street and along the river; the
western, extending north to Fulham Road, is mainly a poor quarter.

Chelsea, especially the riverside district, abounds in historical
associations. At _Cealchythe_ a synod was held in 785. A similar name
occurs in a Saxon charter of the 11th century and in Domesday; in the
16th century it is _Chelcith_. The later termination _ey_ or _ea_ was
associated with the insular character of the land, and the prefix with a
gravel bank (_ceosol_; cf. Chesil Bank, Dorsetshire) thrown up by the
river; but the early suffix _hythe_ is common in the meaning of a haven.
The manor was originally in the possession of Westminster Abbey, but its
history is fragmentary until Tudor times. It then came into the hands of
Henry VIII., passed from him to his wife Catharine Parr, and thereafter
had a succession of owners, among whom were the Howards, to whom it was
granted by Queen Elizabeth, and the Cheynes, from whom it was purchased
in 1712 by Sir Hans Sloane, after which it passed to the Cadogans. The
memorials which crowd the picturesque church and churchyard of St Luke
near the river, commonly known as the Old Church, to a great extent
epitomize the history of Chelsea. Such are those of Sir Thomas More (d.
1535); Lord Bray, lord of the manor (1539), his father and son; Lady
Jane Guyldeford, duchess of Northumberland, who died "at her maner of
Chelse" in 1555; Lord and Lady Dacre (1594-1595); Sir John Lawrence
(1638); Lady Jane Cheyne (1698); Francis Thomas, "director of the china
porcelain manufactory, Lawrence Street, Chelsea" (1770); Sir Hans Sloane
(1753); Thomas Shadwell, poet laureate (1602); Woodfall the printer of
_Junius_ (1844), and many others. More's tomb is dated 1532, as he set
it up himself, though it is doubtful whether he lies beneath it. His
house was near the present Beaufort Street. In the 18th and 19th
centuries Chelsea, especially the parts about the embankment and Cheyne
Walk, was the home of many eminent men, particularly of writers and
artists, with whom this pleasant quarter has long been in favour. Thus
in the earlier part of the period named, Atterbury and Swift lived in
Church Lane, Steele and Smollett in Monmouth House. Later, the names of
Turner, Rossetti, Whistler, Leigh Hunt, Carlyle (whose house in Cheyne
Row is preserved as a public memorial), Count D'Orsay, and Isambard
Brunel, are intimately connected with Chelsea. At Lindsey House Count
Zinzendorf established a Moravian Society (c. 1750). Sir Robert
Walpole's residence was extant till 1810; and till 1824 the bishops of
Winchester had a palace in Cheyne Walk. Queen's House, the home of D.G.
Rossetti (when it was called Tudor House), is believed to take name from
Catharine of Braganza.

Chelsea was noted at different periods for two famous places of
entertainment, Ranelagh (q.v.) in the second half of the 18th century,
and Cremorne Gardens (q.v.) in the middle of the 19th. Don Saltero's
museum, which formed the attraction of a popular coffee-house, was
formed of curiosities from Sir Hans Sloane's famous collections. It was
Sloane who gave to the Apothecaries' Company the ground which they had
leased in 1673 for the Physick Garden, which is still extant, but ceased
in 1902 to be maintained by the Company. At Chelsea Sir John Danvers (d.
1655) introduced the Italian style of gardening which was so greatly
admired by Bacon and soon after became prevalent in England. Chelsea was
formerly famous for a manufacture of buns; the original Chelsea
bun-house, claiming royal patronage, stood until 1839, and one of its
successors until 1888. The porcelain works existed for some 25 years
before 1769, when they were sold and removed to Derby. Examples of the
original Chelsea ware (see CERAMICS) are of great value.

Of buildings and institutions the most notable is Chelsea Royal Hospital
for invalid soldiers, initiated by Charles II. (according to tradition
on the suggestion of Nell Gwynne), and opened in 1694. The hospital
itself accommodates upwards of 500 men, but a system of out-pensioning
was found necessary from the outset, and now relieves large numbers
throughout the empire. The picturesque building by Wren stands in
extensive grounds, which include the former Ranelagh Gardens. A
theological college (King James's) formerly occupied the site; it was
founded in 1610 and was intended to be of great size, but the scheme was
unsuccessful, and only a small part of the buildings was erected. In the
vicinity are the Chelsea Barracks (not actually in the borough). The
Royal Military Asylum for boys, commonly called the Duke of York's
school, founded in 1801 by Frederick, duke of York, for the education of
children connected with the army, was removed in 1909 to new quarters at
Dover. Other institutions are the Whitelands training college for
school-mistresses, in which Ruskin took deep interest; the St Mark's
college for school-masters; the Victoria and the Cheyne hospitals for
children, a cancer hospital, the South-western polytechnic, and a public
library containing an excellent collection relative to local history.

The parliamentary borough of Chelsea returns one member, and includes,
as a detached portion, Kensal Town, north of Kensington. The borough
council consists of a mayor, 6 aldermen and 36 councillors. Area, 659.6
acres.



CHELSEA, a city of Suffolk county, Massachusetts, U.S.A., a suburb of
Boston. Pop. (1890) 27,909; (1900) 34,072, of whom 11,203 were
foreign-born; (1910) 32,452. It is situated on a peninsula between the
Mystic and Chelsea rivers, and Charlestown and East Boston, and is
connected with East Boston and Charlestown by bridges. It is served by
the Boston & Maine and (for freight) by the Boston & Albany railways.
The United States maintains here naval and marine hospitals, and the
state a soldiers' home. Chelsea's interests are primarily industrial.
The value of the city's factory products in 1905 was $13,879,159, the
principal items being rubber and elastic goods ($3,635,211) and boots
and shoes ($2,044,250.) The manufacture of stoves, and of mucilage and
paste are important industries. Flexible tubing for electric wires
(first made at Chelsea 1889) and art tiles are important products. The
first settlement was established in 1624 by Samuel Maverick (c. 1602-c.
1670), the first settler (about 1629) of Noddle's Island (or East
Boston), and one of the first slave-holders in Massachusetts; a loyalist
and Churchman, in 1664 he was appointed with three others by Charles II.
on an important commission sent to Massachusetts and the other New
England colonies (see NICOLLS, RICHARD), and spent the last years of his
life in New York. Until 1739, under the name of Winnisimmet, Chelsea
formed a part of Boston, but in that year it was made a township; it
became a city in 1857. In May 1775 a British schooner in the Mystic
defended by a force of marines was taken by colonial militia under
General John Stark and Israel Putnam,--one of the first conflicts of the
War of Independence. A terrible fire swept the central part of the city
on the 12th of April 1908.

  See Mellen Chamberlain (and others), _History of Chelsea_ (2 vols.,
  Boston, 1908), published by the Massachusetts Historical Society.



CHELTENHAM, a municipal and parliamentary borough of Gloucestershire,
England, 109 m. W. by N. of London by the Great Western railway; served
also by the west and north line of the Midland railway. Pop. (1901)
49,439. The town is well situated in the valley of the Chelt, a small
tributary of the Severn, under the high line of the Cotteswold Hills to
the east, and is in high repute as a health resort. Mineral springs were
accidentally discovered in 1716. The Montpellier and Pittville Springs
supply handsome pump rooms standing in public gardens, and are the
property of the corporation. The Montpellier waters are sulphated, and
are valuable for their diuretic effect, and as a stimulant to the liver
and alimentary canal. The alkaline-saline waters of Pittville are
efficacious against diseases resulting from excess of uric acid. The
parish church of St Mary dates from the 14th century, but is almost
completely modernized. The town, moreover, is wholly modern in
appearance. Assembly rooms opened in 1815 by the duke of Wellington were
removed in 1901. A new town hall, including a central spa and assembly
rooms, was opened in 1903. There are numerous other handsome buildings,
especially in High Street, and the Promenade forms a beautiful broad
thoroughfare, lined with trees. The town is famous as an educational
centre. Cheltenham College (1842) provides education for boys in three
departments, classical, military and commercial; and includes a
preparatory school. The Ladies' College (1854), long conducted by Miss
Beale (q.v.), is one of the most successful in England. The Normal
Training College was founded in 1846 for the training of teachers, male
and female, in national and parochial schools. A free grammar school was
founded in 1568 by Richard Pate, recorder of Gloucester. The art gallery
and museum may be mentioned also. The parliamentary borough returns one
member. The municipal borough is under a mayor, 6 aldermen and 18
councillors. Area, 4726 acres. The urban district of Charlton Kings
(pop. 3806) forms a south-eastern suburb of Cheltenham.

The site of a British village and burying-ground, Cheltenham
(_Celtanhomme_, _Chiltham_, _Chelteham_) was a village with a church in
803. The manor belonged to the crown; it was granted to Henry de Bohun,
earl of Hereford, late in the 12th century, but in 1199 was exchanged
for other lands with the king. It was granted to William de Longespée,
earl of Salisbury, in 1219, but resumed on his death and granted in
dower to Eleanor of Provence in 1243. In 1252 the abbey of Fécamp
purchased the manor, and it afterwards belonged to the priory of
Cormeille, but was confiscated in 1415 as the possession of an alien
priory, and was granted in 1461 to the abbey of Lyon, by which it was
held until, once more returning to the crown at the Dissolution, it was
granted to the family of Dutton. The town is first mentioned in 1223,
when William de Longespée leased the benefit of the markets, fairs and
hundred of Cheltenham to the men of the town for three years; the lease
was renewed by Henry III. in 1226, and again in 1230 for ten years. A
market town in the time of Camden, it was governed by commissioners from
the 18th century in 1876, when it was incorporated; it became a
parliamentary borough in 1832. Henry III. in 1230 had granted to the men
of Cheltenham a market on each Thursday, and a fair on the vigil, feast
and morrow of St James. Although Camden mentions a considerable trade in
malt, the spinning of woollen yarn was the only industry in 1779. After
the discovery of springs in 1716, and the erection of a pump-room in
1738, Cheltenham rapidly became fashionable, the visit of George III.
and the royal princesses in 1788 ensuring its popularity.

  See S. Moreau, _A Tour to Cheltenham Spa_ (Bath, 1738).



CHELYABINSK, a town of Russia, in the Orenburg government, at the east
foot of the Urals, is the head of the Siberian railway, 624 m. by rail
E.N.E. of Samara and 154 m. by rail S.S.E. of Ekaterinburg. Pop. (1900)
25,505. It has tanneries and distilleries, and is the centre of the
trade in corn and produce of cattle for the Ural iron-works. The town
was founded in 1658.



CHELYS (Gr. [Greek: chelus], tortoise; Lat. _testudo_), the common lyre
of the ancient Greeks, which had a convex back of tortoiseshell or of
wood shaped like the shell. The word _chelys_ was used in allusion to
the oldest lyre of the Greeks which was said to have been invented by
Hermes. According to tradition he was attracted by sounds of music while
walking on the banks of the Nile, and found they proceeded from the
shell of a tortoise across which were stretched tendons which the wind
had set in vibration (_Homeric Hymn to Hermes_, 47-51). The word has
been applied arbitrarily since classic times to various stringed
instruments, some bowed and some twanged, probably owing to the back
being much vaulted. Kircher (_Musurgia_, i. 486) applied the name of
_chelys_ to a kind of viol with eight strings. Numerous representations
of the _chelys_ lyre or _testudo_ occur on the Greek vases, in which the
actual tortoiseshell is depicted; a good illustration is given in _Le
Antichità, di Ercolano_ (vol. i. pl. 43). Propertius (iv. 6) calls the
instrument the _lyra testudinea_. Scaliger (on Manilius, _Astronomicon_,
Proleg. 420) was probably the first writer to draw attention to the
difference, between _chelys_ and _cithara_ (q.v.).     (K. S.)



CHEMICAL ACTION, the term given to any process in which change in
chemical composition occurs. Such processes may be set up by the
application of some form of energy (heat, light, electricity, &c.) to a
substance, or by the mixing of two or more substances together. If two
or more substances be mixed one of three things may occur. First, the
particles may be mechanically intermingled, the degree of association
being dependent upon the fineness of the particles, &c. Secondly, the
substances may intermolecularly penetrate, as in the case of
gas-mixtures and solutions. Or thirdly they may react chemically. The
question whether, in any given case, we have to deal with a physical
mixture or a chemical compound is often decided by the occurrence of
very striking phenomena. To take a simple example:--oxygen and hydrogen
are two gases which may be mixed in all proportions at ordinary
temperatures, and it is easy to show that the properties of the products
are simply those of mixtures of the two free gases. If, however, an
electric spark be passed through the mixtures, powerful chemical union
ensues, with its concomitants, great evolution of heat and consequent
rise of temperature, and a compound, water, is formed which presents
physical and chemical properties entirely different from those of its
constituents.

In general, powerful chemical forces give rise to the evolution of large
quantities of heat, and the properties of the resulting substance differ
vastly more from those of its components than is the case with simple
mixtures. This constitutes a valuable criterion as to whether mere
mixture is involved on the one hand, or strong chemical union on the
other. When, however, the chemical forces are weak and the reaction,
being incomplete, leads to a state of chemical equilibrium, in which
all the reacting substances are present side by side, this criterion
vanishes. For example, the question whether a salt combines with water
molecules when dissolved in water cannot be said even yet to be fully
settled, and, although there can be no doubt that solution is, in many
cases, attended by chemical processes, still we possess as yet no means
of deciding, with certainty, how many molecules of water have bound
themselves to a single molecule of the dissolved substance (_solute_).
On the other hand, we possess exact methods of testing whether gases or
solutes in dilute solution react one with another and of determining the
equilibrium state which is attained. For if one solute react with
another on adding the latter to its solution, then corresponding to the
decrease of its concentration there must also be a decrease of vapour
pressure, and of solubility in other solvents; further, in the case of a
mixture of gases, the concentration of each single constituent follows
from its solubility in some suitable solvent. We thus obtain the answer
to the question: whether the concentration of a certain constituent has
decreased during mixing, i.e. whether it has reacted chemically.

When a compound can be obtained in a pure state, analysis affords us an
important criterion of its chemical nature, for unlike mixtures, the
compositions of which are always variable within wider or narrower
limits, chemical compounds present definite and characteristic
mass-relations, which find full expression in the atomic theory
propounded by Dalton (see ATOM). According to this theory a mixture is
the result of the mutual interpenetration of the molecules of
substances, which remain unchanged as such, whilst chemical union
involves changes more deeply seated, inasmuch as new molecular species
appear. These new substances, if well-defined chemical compounds, have a
perfectly definite composition and contain a definite, generally small,
number of elementary atoms, and therefore the law of constant
proportions follows at once, and the fact that only an integral number
of atoms of any element may enter into the composition of any molecule
determines the law of multiple proportions.


  Nature of chemical forces.

These considerations bring us face to face with the task of more closely
investigating the nature of chemical forces, in other words, of
answering the question: what forces guide the atoms in the formation of
a new molecular species? This problem is still far from being completely
answered, so that a few general remarks must suffice here.

It is remarkable that among the most stable chemical compounds, we find
combinations of atoms of one and the same element. Thus, the stability
of the di-atomic molecule N2 is so great, that no trace of dissociation
has yet been proved even at the highest temperatures, and as the
constituent atoms of the molecule N2 must be regarded as absolutely
identical, it is clear that "polar" forces cannot be the cause of all
chemical action. On the other hand, especially powerful affinities are
also at work when so-called electro-positive and electro-negative
elements react. The forces which here come into play appear to be
considerably greater than those just mentioned; for instance, potassium
fluoride is perhaps the most stable of all known compounds.

It is also to be noticed that the combinations of the electro-negative
elements (metalloids) with one another exhibit a metalloid character,
and also we find, in the mutual combinations of metals, all the
characteristics of the metallic state; but in the formation of a _salt_
from a metal and a metalloid we have an entirely new substance, quite
different from its components; and at the same time, the product is seen
to be an electrolyte, i.e. to have the power of splitting up into a
positively and a negatively charged constituent when dissolved in some
solvent. These considerations lead to the conviction that forces of a
"polar" origin play an important part here, and indeed we may make the
general surmise that in the act of chemical combination forces of both a
non-polar and polar nature play a part, and that the latter are in all
probability identical with the electric forces.

It now remains to be asked--what are the laws which govern the action
of these forces? This question is of fundamental importance, since it
leads directly to those laws which regulate the chemical process.
Besides the already mentioned fundamental law of chemical combination,
that of constant and multiple proportions, there is the law of chemical
mass-action, discovered by Guldberg and Waage in 1867, which we will now
develop from a kinetic standpoint.

_Kinetic Basis of the Law of Chemical Mass-action._--We will assume that
the molecular species A1, A2, ... A'1, A'2, ... are present in a
homogeneous system, where they can react on each other only according to
the scheme

  A1 + A2 + ... <--> A'1 + A'2 + ...;

this is a special case of the general equation

  n1A1 + n2A2 + ... <--> n'1A'1 + n'2A'2 + ...,

in which only one molecule of each substance takes part in the reaction.
The reacting substances may be either gaseous or form a liquid mixture,
or be dissolved in some selected solvent; but in each case we may state
the following considerations regarding the course of the reaction. For a
transformation to take place from left to right in the sense of the
reaction equation, all the molecules A1, A2, ... must clearly collide at
one point; otherwise no reaction is possible, since we shall not
consider side-reactions. Such a collision need not of course bring about
that transposition of the atoms of the single molecules which
constitutes the above reaction. Much rather must it be of such a kind as
is favourable to that loosening of the bonds that bind the atoms in the
separate molecules, which must precede this transposition. Of a large
number of such collisions, therefore, only a certain smaller number will
involve a transposition from left to right in the sense of the equation.
But this number will be the same under the same external conditions, and
the greater the more numerous the collisions; in fact a direct ratio
must exist between the two. Bearing in mind now, that the number of
collisions must be proportional to each of the concentrations of the
bodies A1, A2, ..., and therefore, on the whole, to the product of all
these concentrations, we arrive at the conclusion that the velocity v of
the transposition from left to right in the sense of the reaction
equation is v = kc1c2 ..., in which c1, c2, ... represent the spatial
concentrations, i.e. the number of gram-molecules of the substances A1,
A2, ... present in one litre, and k is, at a given temperature, a
constant which may be called the velocity-coefficient.

Exactly the same consideration applies to the molecules A'1, A'2.... Here
the velocity of the change from right to left in the sense of the
reaction-equation increases with the number of collisions of all these
molecules at one point, and this is proportional to the product of all the
concentrations. If k' denotes the corresponding proportionality-factor,
then the velocity v' of the change from right to left in the sense of the
reaction-equation is v' = k'c'1c'2.... These spatial concentrations are
often called the "active masses" of the reacting components. Hence the
reaction-velocity in the sense of the reaction-equation from left to
right, or the reverse, is proportional to the product of the
"active-masses" of the left-hand or right-hand components respectively.


  Law of chemical statics.

Neither v nor v' can be separately investigated, and the measurements of
the course of a reaction always furnish only the difference of these two
quantities. The reaction-velocity actually observed represents the
difference of these two partial reaction-velocities, whilst the amount
of change observed during any period of time is equal to the change in
the one direction, minus the change in the opposite direction. It must
not be assumed, however, that on the attainment of equilibrium all
action has ceased, but rather that the velocity of change in one
direction has become equal to that in the opposite direction, with the
result that no further total change can be observed, i.e. the system has
reached equilibrium, for which the relation v - v' = 0 must therefore
hold, or what is the same thing

  kc1c2 ... = k'c'1c'2 ...,

this is the fundamental law of chemical statics.

The conception that the equilibrium is not to be attributed to absolute
indifference between the reacting bodies, but that these continue to
exert their mutual actions undiminished and the opposing changes now
balance, is of fundamental significance in the interpretation of changes
of matter in general. This is generally expressed in the form: _the
equilibrium in this and other analogous cases is not static but
dynamic._ This conception was a direct result of the kinetic-molecular
considerations, and was applied with special success to the development
of the kinetic theory of gases. Thus with Clausius, we conceive the
equilibrium of water-vapour with water, not as if neither water
vaporized nor vapour condensed, but rather as though the two processes
went on unhindered in the equilibrium state, i.e. during contact of
saturated vapour with water, in a given time, as many water molecules
passed through the water surface in one direction as in the opposite
direction. This view, as applied to chemical changes, was first advanced
by A.W. Williamson (1851), and further developed by C.M. Guldberg and P.
Waage and others.


  Law of chemical kinetics.

From the previous considerations it follows that the reaction-velocity
at every moment, i.e. the velocity with which the chemical process
advances towards the equilibrium state, is given by the equation

  V = v - v' = kc1c2 ... - k'c1c'2 ...;

this states the fundamental law of chemical kinetics.

The equilibrium equation is simply a special case of this more general
one, and results when the total velocity is written zero, just as in
analytical mechanics the equilibrium conditions follow at once by
specialization of the general equations of motion.

No difficulty presents itself in the generalization of the previous
equations for the reaction which proceeds after the scheme

  n1A1 + n2A2 + ... = n'1A'1 + n'2A'2 + ...,

where n1, n2, ..., n'1, n'2, ... denote the numbers of molecules of the
separate substances which take part in the reaction, and are therefore
whole, mostly small, numbers (generally one or two, seldom three or
more). Here as before, v and v' are to be regarded as proportional to
the number of collisions at one point of all molecules necessary to the
respective reaction, but now n1 molecules of A1, n2 molecules of A2,
&c., must collide for the reaction to advance from left to right in the
sense of the equation; and similarly n'1 molecules of A'1, n'2 molecules
of A'2, &c., must collide for the reaction to proceed in the opposite
direction. If we consider the path of a single, arbitrarily chosen
molecule over a certain time, then the number of its collisions with
other similar molecules will be proportional to the concentration C of
that kind of molecule to which it belongs. The number of encounters
between two molecules of the kind in question, during the same time,
will be in general C times as many, i.e. the number of encounters of two
of the same molecules is proportional to the square of the concentration
C; and generally, the number of encounters of n molecules of one kind
must be regarded as proportional to the nth power of C, i.e. C^n.

The number of collisions of n1 molecules of A1, n2 molecules of A2 ...
is accordingly proportional to C1^{n1}C2^{n2} ..., and the
reaction-velocity corresponding to it is therefore

  v = kC1^{n1}C2^{n2} ...,

and similarly the opposed reaction-velocity is

  v' = k'C'1^{n'1}C'2^{n'2} ...;

the resultant reaction-velocity, being the difference of these two
partial velocities, is therefore

  V = v - v' = kC1^{n1}C2^{n2} ... - k'C'1^{n'1}C'2^{n'2} ...

This is the most general expression of the law of chemical mass-action,
for the case of homogeneous systems.

Equating V to zero, we obtain the equation for the equilibrium state,
viz.

  C1^{n1}C2^{n2} ... / C'1^{n'1}C'2^{n'2} ... = k / k' = K;

K is called the "equilibrium-constant."


  Limitations and applications of the laws.

These formulae hold for gases and for dilute solutions, but assume the
system to be homogeneous, i.e. to be either a homogeneous gas-mixture or
a homogeneous dilute solution. The case in which other states of matter
share in the equilibrium permits of simple treatment when the substances
in question may be regarded as pure, and consequently as possessing
definite vapour-pressures or solubilities at a given temperature. In
this case the molecular species in question, which is, at the same time,
present in excess and is hence usually, called a _Bodenkörper_, must
possess a constant concentration in the gas-space or solution. But since
the left-hand side of the last equation contains only variable
quantities, it is simplest and most convenient to absorb these constant
concentrations into the equilibrium-constant; whence we have the rule:
leave the molecular species present as _Bodenkörper_ out of account,
when determining the concentration-product. Guldberg and Waage expressed
this in the form "the active mass of a solid substance is constant." The
same is true of liquids when these participate in the pure state in the
equilibrium, and possess therefore a definite vapour-pressure or
solubility. When, finally, we are not dealing with a dilute solution but
with any kind of mixture whatever, it is simplest to apply the law of
mass-action to the gaseous mixture in equilibrium with this. The
composition of the liquid mixture is then determinable when the
vapour-pressures of the separate components are known. This, however, is
not often the case; but in principle this consideration is important,
since it involves the possibility of extending the law of chemical
mass-action from ideal gas-mixtures and dilute solutions, for which it
primarily holds, to any other system whatever.

The more recent development of theoretical chemistry, as well as the
detailed study of many chemical processes which have found technical
application, leads more and more convincingly to the recognition that in
the law of chemical mass-action we have a law of as fundamental
significance as the law of constant and multiple proportions. It is
therefore not without interest to briefly touch upon the development of
the doctrine of chemical affinity.

_Historical Development of the Law of Mass-action._--The theory
developed by Torbern Olof Bergman in 1775 must be regarded as the first
attempt of importance to account for the mode of action of chemical
forces. The essential principle of this may be stated as follows:--The
magnitude of chemical affinity may be expressed by a definite number; if
the affinity of the substance A is greater for the substance B than for
the substance C, then the latter (C) will be completely expelled by B
from its compound with A, in the sense of the equation A·C + B = A·B +
C. This theory fails, however, to take account of the influence of the
relative masses of the reacting substances, and had to be abandoned as
soon as such an influence was noticed. An attempt to consider this
factor was made by Claude Louis Berthollet (1801), who introduced the
conception of chemical equilibrium. The views of this French chemist may
be summed up in the following sentence:--Different substances have
different affinities for each other, which only come into play on
immediate contact. The condition of equilibrium depends not only upon
the chemical affinity, but also essentially upon the relative masses of
the reacting substances.

Essentially, Berthollet's idea is to-day the guiding principle of the
doctrine of affinity. This is especially true of our conceptions of many
reactions which, in the sense of Bergman's idea, proceed to completion,
i.e. until the reacting substances are all used up; but only for this
reason, viz. that one or more of the products of the reaction is removed
from the reaction mixture (either by crystallization, evaporation or
some other process), and hence the reverse reaction becomes impossible.
Following Berthollet's idea, two Norwegian investigators, C.M. Guldberg
and Peter Waage, succeeded in formulating the influence of the reacting
masses in a simple law--the law of chemical mass-action already defined.
The results of their theoretical and experimental studies were published
at Christiania in 1867 (_Études sur les affinités chimiques_); this work
marks a new epoch in the history of chemistry. Even before this,
formulae to describe the progress of certain chemical reactions, which
must be regarded as applications of the law of mass-action, had been put
forward by Ludwig Wilhelmy (1850), and by A.G. Vernon-Harcourt and
William Esson (1856), but the service of Guldberg and Waage in having
grasped the law in its full significance and logically applied it in all
directions, remains of course undiminished. Their treatise remained
quite unknown; and so it happened that John Hewitt Jellett (1873), J.H.
van't Hoff (1877), and others independently developed the same law. The
thermodynamic basis of the law of mass-action is primarily due to
Horstmann, J. Willard Gibbs and van't Hoff.

_Applications._--Let us consider, as an example of the application of
the law of mass-action, the case of the dissociation of water-vapour,
which takes place at high temperatures in the sense of the equation 2H2O
= 2H2 + O2. Representing the concentrations of the corresponding
molecular species by [H2], &c., the expression [H2]² [O2] / [H2O]² must
be constant at any given temperature. This shows that the dissociation
is set back by increasing the pressure; for if the concentrations of all
three kinds of molecules be increased by strong compression, say to ten
times the former amounts, then the numerator is increased one thousand,
the denominator only one hundred times. Hence if the original
equilibrium-constant is to hold, the dissociation must go back, and,
what is more, by an exactly determinable amount. At 2000° C.
water-vapour is only dissociated to the extent of a few per cent;
therefore, even when only a small excess of oxygen or hydrogen be
present, the numerator in the foregoing expression is much increased,
and it is obvious that in order to restore the equilibrium state, the
concentration of the other component, hydrogen or oxygen as the case may
be, must diminish. In the case of slightly dissociated substances,
therefore, even a relatively small excess of one component is sufficient
to set back the dissociation substantially.

_Chemical Kinetics._--It has been already mentioned that the law of
chemical mass-action not only defines the conditions for chemical
equilibrium, but contains at the same time the principles of chemical
kinetics. The previous considerations show indeed that the actual
progress of the reaction is determined by the difference of the
reaction-velocities in the one and the other (opposed) direction, in the
sense of the corresponding reaction-equation. Since the
reaction-velocity is given by the amount of chemical change in a small
interval of time, the law of chemical mass-action supplies a
differential equation, which, when integrated, provides formulae which,
as numerous experiments have shown, very happily summarize the course of
the reaction. For the simplest case, in which a single species of
molecule undergoes almost complete decomposition, so that the
reaction-velocity in the reverse direction may be neglected, we have the
simple equation

  dx/dt = k(a-x)

and if x = 0 when t = 0 we have by integration

  k = t^{-1}log{a/(a-x)}.

Theory of explosive combustion

We will now apply these conclusions to the theory of the ignition of an
explosive gas-mixture, and in particular to the combustion of "knallgas"
(a mixture of hydrogen and oxygen) to water-vapour. At ordinary
temperatures knallgas undergoes practically no change, and it might be
supposed that the two gases, oxygen and hydrogen, have no affinity for
each other. This conclusion, however, is shown to be incorrect by the
observation that it is only necessary to add some suitable catalyst such
as platinum-black in order to immediately start the reaction. We must
therefore conclude that even at ordinary temperatures strong chemical
affinity is exerted between oxygen and hydrogen, but that at low
temperatures this encounters great frictional resistances, or in other
words that the reaction-velocity is very small. It is a matter of
general experience that the resistances which the chemical forces have
to overcome diminish with rising temperature, i.e. the reaction-velocity
increases with temperature. Therefore, when we warm the knallgas, the
number of collisions of oxygen and hydrogen molecules favourable to the
formation of water becomes greater and greater, until at about 500° the
gradual formation of water is observed, while at still higher
temperatures the reaction-velocity becomes enormous. We are now in a
position to understand what is the result of a strong local heating of
the knallgas, as, for example, by an electric spark. The strongly heated
parts of the knallgas combine to form water-vapour with great velocity
and the evolution of large amounts of heat, whereby the adjacent parts
are brought to a high temperature and into a state of rapid reaction,
i.e. we observe an ignition of the whole mixture. If we suppose the
knallgas to be at a very high temperature, then its combustion will be
no longer complete owing to the dissociation of water-vapour, whilst at
extremely high temperatures it would practically disappear. Hence it is
clear that knallgas appears to be stable at low temperatures only
because the reaction-velocity is very small, but that at very high
temperatures it is really stable, since no chemical forces are then
active, or, in other words, the chemical affinity is very small.

The determination of the question whether the failure of some reaction
is due to an inappreciable reaction-velocity or to absence of chemical
affinity, is of fundamental importance, and only in the first case can
the reaction be hastened by catalysts.

Many chemical compounds behave like knallgas. Acetylene is stable at
ordinary temperatures, inasmuch as it only decomposes slowly; but at the
same time it is explosive, for the decomposition when once started is
rapidly propagated, on account of the heat evolved by the splitting up
of the gas into carbon and hydrogen. At very high temperatures, however,
acetylene acquires real stability, since carbon and hydrogen then react
to form acetylene.


  Explosion-waves.

Many researches have shown that the combustion of an inflammable
gas-mixture which is started at a point, e.g. by an electric spark, may
be propagated in two essentially different ways. The characteristic of
the slower combustion consists in this, viz. that the high temperature
of the previously ignited layer spreads by conduction, thereby bringing
the adjacent layers to the ignition-temperature; the velocity of the
propagation is therefore conditioned in the first place by the magnitude
of the conductivity for heat, and more particularly, in the second
place, by the velocity with which a moderately heated layer begins to
react chemically, and so to rise gradually in temperature, i.e.
essentially by the change of reaction-velocity with temperature. A
second entirely independent mode of propagation of the combustion lies
at the basis of the phenomenon that an explosive gas-mixture can be
ignited by strong compression or--more correctly--by the rise of
temperature thereby produced. The increase of the concentrations of the
reacting substances consequent upon this increase of pressure raises the
reaction-velocity in accordance with the law of chemical mass-action,
and so enormously favours the rapid evolution of the heat of combustion.

It is therefore clear that such a powerful compression-wave can not only
initiate the combustion, but also propagate it with extremely high
velocity. Indeed a compression-wave of this kind passes through the
gas-mixture, heated by the combustion to a very high temperature. It
must, however, be propagated considerably faster than an ordinary
compression-wave, for the result of ignition in the compressed (still
unburnt) layer is the production of a very high pressure, which must in
accordance with the principles of wave-motion increase the velocity of
propagation. The absolute velocity of the explosion-wave would seem, in
the light of these considerations, to be susceptible of accurate
calculation. It is at least clear that it must be considerably higher
than the velocity of sound in the mass of gas strongly heated by the
explosion, and this is confirmed by actual measurements (see below)
which show that the velocity of the explosion-wave is from one and a
half times to double that of sound-waves at the combustion temperature.

We are now in a position to form the following picture of the processes
which follow upon the ignition of a combustible gas-mixture contained in
a long tube. First we have the condition of slow combustion; the heat is
conveyed by conduction to the adjacent layers, and there follows a
velocity of propagation of a few metres per second. But since the
combustion is accompanied by a high increase of pressure, the adjacent,
still unburnt layers are simultaneously compressed, whereby the
reaction-velocity increases, and the ignition proceeds faster. This
involves still greater compression of the next layers, and so if the
mixture be capable of sufficiently rapid combustion, the velocity of
propagation of the ignition must continually increase. As soon as the
compression in the still unburnt layers becomes so great that
spontaneous ignition results, the now much more pronounced
compression-waves excited with simultaneous combustion must be
propagated with very great velocity, i.e. we have spontaneous
development of an "explosion-wave." M.P.E. Berthelot, who discovered the
presence of such explosion-waves, proved their velocity of propagation
to be independent of the pressure, the cross-section of the tubes in
which the explosive gas-mixture is contained, as well as of the material
of which these are made, and concluded that this velocity is a constant,
characteristic of the particular mixture. The determination of this
velocity is naturally of the highest interest.

In the following table Berthelot's results are given along with the
later (1891) concordant ones of H.B. Dixon, the velocities of
propagation of explosions being given in metres per second.

  +-------------------------------------+---------------------+
  |                                     | Velocity of Wave in |
  |           Reacting Mixture.         | Metres per second.  |
  |                                     +-----------+---------+
  |                                     | Berthelot.| Dixon.  |
  +-------------------------------------+-----------+---------+
  |Hydrogen and oxygen,        H2+O     |   2810    |  2821   |
  |Hydrogen and nitrous oxide, H2+N2O   |   2284    |  2305   |
  |Methane and oxygen,         CH4+4O   |   2287    |  2322   |
  |Ethylene  "  "              C2H4+6O  |   2210    |  2364   |
  |Acetylene "  "              C2H2+5O  |   2482    |  2391   |
  |Cyanogen  "  "              C2N2+4O  |   2195    |  2321   |
  |Hydrogen and chlorine,      H2+Cl2   |    ..     |  1730   |
  |    "     "      "          2H2+Cl2  |    ..     |  1849   |
  +-------------------------------------+-----------+---------+

The maximum pressure of the explosion-wave possesses very high values;
it appears that a compression of from 1 to 30-40 atmospheres is
necessary to produce spontaneous ignition of mixtures of oxygen and
hydrogen. But since the heat evolved in the path of the explosion causes
a rise of temperature of 2000°-3000°, i.e. a rise of absolute
temperature about four times that directly following upon the initial
compression, we are here concerned with pressures amounting to
considerably more than 100 atmospheres. Both the magnitude of this
pressure and the circumstance that it so suddenly arises are peculiar to
the very powerful forces which distinguish the explosion-wave from the
slow combustion-wave.

_Nascent State._--The great reactive power of freshly formed or nascent
substances (_status nascens_)may be very simply referred to the
principles of mass-action. As is well known, this phenomenon is
specially striking in the case of hydrogen, which may therefore be taken
as a typical example. The law of mass-action affirms the action of a
substance to be the greater the higher its concentration, or, for a gas,
the higher its partial-pressure. Now experience teaches that those
metals which liberate hydrogen from acids are able to supply the latter
under extremely high pressure, and we may therefore assume that the
hydrogen which results, for example, from the action of zinc upon
sulphuric acid is initially under very high pressures which are then
afterwards relieved. Hence the hydrogen during liberation exhibits much
more active powers of reduction than the ordinary gas.

A deeper insight into the relations prevailing here is offered from the
atomistic point of view. From this we are bound to conclude that the
hydrogen is in the first instance evolved in the form of free atoms, and
since the velocity of the reaction H + H = H2 at ordinary temperatures,
though doubtless very great, is not practically instantaneous, the
freshly generated hydrogen will contain a remnant of free atoms, which
are able to react both more actively and more rapidly. Similar
considerations are of course applicable to other cases.

_Ion-reactions._--The application of the law of chemical mass action is
much simplified in the case in which the reaction-velocity is enormously
great, when practically an instantaneous adjustment of the equilibrium
results. Only in this case can the state of the system, which pertains
after mixing the different components, be determined merely from
knowledge of the equilibrium-constant. This case is realized in the
reactions between gases at very high temperatures, which have, however,
been little investigated, and especially by the reactions between
electrolytes, the so-called ion-reactions. In this latter case, which
has been thoroughly studied on account of its fundamental importance for
inorganic qualitative and quantitative analysis, the degrees of
dissociation of the various electrolytes (acids, bases and salts) are
for the most part easily determined by the aid of the freezing-point
apparatus, or of measurements of the electric conductivity; and from
these data the equilibrium-constant K may be calculated. Moreover, it
can be shown that the state of the system can be determined when the
equilibrium constants of all the electrolytes which are present in the
common solution are known. If this be coupled with the law that the
solubility of solid substances, as with vapour-pressures, is independent
of the presence of other electrolytes, it is sufficient to know the
solubilities of the electrolytes in question, in order to be able to
determine which substances must participate in the equilibrium in the
solid state, i.e. we arrive at the theory of the formation and solution
of precipitates.


  Strength of acids and bases.

As an illustration of the application of these principles, we shall deal
with a problem of the doctrine of affinity, namely, that of the relative
strengths of acids and bases. It was quite an early and often repeated
observation that the various acids and bases take part with very varying
intensity or avidity in those reactions in which their acid or basic
nature comes into play. No success attended the early attempts at giving
numerical expression to the strengths of acids and bases, i.e. of
finding a numerical coefficient for each acid and base, which should be
the quantitative expression of the degree of its participation in those
specific reactions characteristic of acids and bases respectively.
Julius Thomsen and W. Ostwald attacked the problem in a far-seeing and
comprehensive manner, and arrived at indisputable proof that the
property of acids and bases of exerting their effects according to
definite numerical coefficients finds expression not only in
salt-formation but also in a large number of other, and indeed very
miscellaneous, reactions.

When Ostwald compared the order of the strengths of acids deduced from
their competition for the same base, as determined by Thomsen's
thermo-chemical or his own volumetric method, with that order in which
the acids arrange themselves according to their capacity to bring
calcium oxalate into solution, or to convert acetamide into ammonium
acetate, or to split up methyl acetate into methyl alcohol and acetic
acid catalytically, or to invert cane-sugar, or to accelerate the mutual
action of hydriodic on bromic acid, he found that in all these
well-investigated and very miscellaneous cases the same succession of
acids in the order of their strengths is obtained, whichever one of the
above chemical processes be chosen as measure of these strengths. It is
to be noticed that all these chemical changes cited took place in dilute
aqueous solution, consequently the above order of acids refers only to
the power to react under these circumstances. The order of acids proved
to be fairly independent of temperature. While therefore the above
investigations afforded a definite qualitative solution of the order of
acids according to strengths, the determination of the quantitative
relations offered great difficulties, and the numerical coefficients,
determined from the separate reactions, often displayed great
variations, though occasionally also surprising agreement. Especially
great were the variations of the coefficients with the concentration,
and in those cases in which the concentration of the acid changed
considerably during the reaction, the calculation was naturally quite
uncertain. Similar relations were found in the investigation of bases,
the scope of which, however, was much more limited.

These apparently rather complicated relations were now cleared up at
one stroke, by the application of the law of chemical mass-action on the
lines indicated by S. Arrhenius in 1887, when he put forward the theory
of electrolytic dissociation to explain that peculiar behaviour of
substances in aqueous solution first recognized by van't Hoff in 1885.
The formulae which must be made use of here in the calculation of the
equilibrium-relations follow naturally by simple application of the law
of mass-action to the corresponding ion-concentrations.

The peculiarities which the behaviour of acids and bases presents, and,
according to the theory of Arrhenius, must present--peculiarities which
found expression in the very early distinction between neutral solutions
on the one hand, and acid or basic ones on the other, as well as in the
belief in a polar antithesis between the two last--must now, in the
light of the theory of electrolytic dissociation, be conceived as
follows:--

The reactions characteristic of acids in aqueous solution, which are
common to and can only be brought about by acids, find their explanation
in the fact that this class of bodies gives rise on dissociation to a
common molecular species, namely, the positively charged hydrogen-ion
(+H). The specific chemical actions peculiar to acids are therefore to
be attributed to the hydrogen-ion just as the actions common to all
chlorides are to be regarded as those of the free chlorine-ions. In like
manner, the reactions characteristic of bases in solution are to be
attributed to the negatively charged hydroxyl-ions (-OH), which result
from the dissociation of this class of bodies.

A solution has an acid reaction when it contains an excess of
hydrogen-ions, and a basic reaction when it contains an excess of
hydroxyl-ions. If an acid and an alkaline solution be brought together
mutual neutralization must result, since the positive H-ions and the
negative OH-ions cannot exist together in view of the extremely weak
conductivity of pure water and its consequent slight electrolytic
dissociation, and therefore they must at once combine to form
electrically neutral molecules, in the sense of the equation

  [+H] + [-OH] = H2O.

In this lies the simple explanation of the "polar" difference between
acid and basic solutions. This rests essentially upon the fact that the
ion peculiar to acids and the ion peculiar to bases form the two
constituents of water, i.e. of that solvent in which we usually study
the course of the reaction. The idea of the "strength" of an acid or
base at once arises. If we compare equivalent solutions of various
acids, the intensity of those actions characteristic of them will be the
greater the more free hydrogen-ions they contain; this is an immediate
consequence of the law of chemical mass-action. The degree of
electrolytic dissociation determines, therefore, the strength of acids,
and a similar consideration leads to the same result for bases.

Now the degree of electrolytic dissociation changes with concentration
in a regular manner, which is given by the law of mass-action. For if C
denote the concentration of the electrolyte and a its degree of
dissociation, the above law states that

  C²a²/C(1-a) = Ca²/(1-a) = K.

At very great dilutions the dissociation is complete, and equivalent
solutions of the most various acids then contain the same number of
hydrogen-ions, or, in other words, are equally strong; and the same is
true of the hydroxyl-ions of bases. The dissociation also decreases with
increasing concentration, but at different rates for different
substances, and the relative "strengths" of acids and bases must hence
change with concentration, as was indeed found experimentally. The
dissociation-constant K is the measure of the variation of the degree of
dissociation with concentration, and must therefore be regarded as the
measure of the strengths of acids and bases. So that in this special
case we are again brought to the result which was stated in general
terms above, viz. that the dissociation-coefficient forms the measure of
the reactivity of a dissolved electrolyte. Ostwald's series of acids,
based upon the investigation of the most various reactions, should
therefore correspond with the order of their dissociation-constants, and
further with the order of their freezing-point depressions in
equivalent solutions, since the depression of the freezing-point
increases with the degree of electrolytic dissociation. Experience
confirms this conclusion completely. The degree of dissociation of an
acid, at a given concentration, for which its molecular conductivity is
A, is shown by the theory of electrolytic dissociation to be a =
A/A[oo]; A[oo], the molecular conductivity at very great dilution in
accordance with the law of Kohlrausch, is u + v, where u and v are the
ionic-mobilities (see CONDUCTION, ELECTRIC). Since u, the ionic-mobility
of the hydrogen ion, is generally more than ten times as great as v, the
ionic-mobility of the negative acid-radical, A[oo] has approximately
the same value (generally within less than 10%) for the different acids,
and the molecular-conductivity of the acids in equivalent concentration
is at least approximately proportional to the degree of electrolytic
dissociation, i.e. to the strength.

In general, therefore, the order of conductivities is identical with
that in which the acids exert their specific powers. This remarkable
parallelism, first perceived by Arrhenius and Ostwald in 1885, was the
happy development which led to the discovery of electrolytic
dissociation (see CONDUCTION, ELECTRIC; and SOLUTION).

_Catalysis._--We have already mentioned the fact, early known to
chemists, that many reactions proceed with a marked increase of velocity
in presence of many foreign substances. With Berzelius we call this
phenomenon "catalysis," by which we understand that general acceleration
of reactions which also progress when left to themselves, in the
presence of certain bodies which do not change in amount (or only
slightly) during the course of the reaction. Acids and bases appear to
act catalytically upon all reactions involving consumption or liberation
of water, and indeed that action is proportional to the concentration of
the hydrogen or hydroxyl-ions. Further, the decomposition of hydrogen
peroxide is "catalysed" by iodine-ions, the condensation of two
molecules of benzaldehyde to benzoin by cyanogen-ions. One of the
earliest known and technically most important instances of catalysis is
that of the oxidation of sulphur dioxide to sulphuric acid by oxygen in
the presence of oxides of nitrogen. Other well-known and remarkable
examples are the catalysis of the combustion of hydrogen and of sulphur
dioxide in oxygen by finely-divided platinum. We may also mention the
interesting work of Dixon and Baker, which led to the discovery that a
large number of gas-reactions, e.g. the combustion of carbon monoxide,
the dissociation of sal-ammoniac vapour, and the action of sulphuretted
hydrogen upon the salts of heavy metals, cease when water-vapour is
absent, or at least proceed with greatly diminished velocity.

"Negative catalysis," i.e. the retardation of a reaction by addition of
some substance, which is occasionally observed, appears to depend upon
the destruction of a "positive catalyte" by the body added.

A catalyte can have no influence, however, upon the affinity of a
process, since that would be contrary to the second law of
thermodynamics, according to which affinity of an isothermal process,
which is measured by the maximum work, only depends upon the initial and
final states. The effect of a catalyte is therefore limited to the
resistances opposing the progress of a reaction, and does not influence
its driving-force or affinity. Since the catalyte takes no part in the
reaction its presence has no effect on the equilibrium-constant. This,
in accordance with the law of mass-action, is the ratio of the separate
reaction-velocities in the two contrary directions. A catalyte must
therefore always accelerate the reverse-reaction. If the velocity of
formation of a body be increased by addition of some substance then its
velocity of decomposition must likewise increase. We have an example of
this in the well-known fact that the formation, and no less the
saponification, of esters, proceeds with increased velocity in the
presence of acids, while the observation that in absence of water-vapour
neither gaseous ammonium chloride dissociates nor dry ammonia combines
with hydrogen chloride becomes clear on the same grounds.

A general theory of catalytic phenomena does not at present exist. The
formation of intermediate products by the action of the reacting
substance upon the catalyte has often been thought to be the cause of
these. These intervening products, whose existence in many cases has
been proved, then split up into the catalyte and the reaction-product.
Thus chemists have sought to ascribe the influence of oxides of nitrogen
on the formation of sulphuric acid to the initial formation of
nitrosyl-sulphuric acid, SO2(OH)(NO2), from the mixture of sulphur
dioxide, oxides of nitrogen and air, which then reacted with water to
form sulphuric and nitrous acids. When the velocity of such intermediate
reactions is greater than that of the total change, such an explanation
may suffice, but a more certain proof of this theory of catalysis has
only been reached in a few cases, though in many others it appears very
plausible. Hence it is hardly possible to interpret all catalytic
processes on these lines.

In regard to catalysis in heterogeneous systems, especially the
hastening of gas-reactions by platinum, it is very probable that it is
closely connected with the solution or absorption of the gases on the
part of the metal. From the experiments of G. Bredig it seems that
colloidal solutions of a metal act like the metal itself. The action of
a colloidal-platinum solution on the decomposition of hydrogen peroxide
is still sensible even at a dilution of 1/70,000,000 grm.-mol. per
litre; indeed the activity of this colloidal-platinum solution calls to
mind in many ways that of organic ferments, hence Bredig has called it
an "inorganic ferment." This analogy is especially striking in the
change of their activity with time and temperature, and in the
possibility, by means of bodies like sulphuretted hydrogen, hydrocyanic
acid, &c., which act as strong poisons upon the latter, of "poisoning"
the former also, i.e. of rendering it inactive. In the case of the
catalytic action of water-vapour upon many processes of combustion
already mentioned, a part of the effect is probably due to the
circumstance, disclosed by numerous experiments, that the union of
hydrogen and oxygen proceeds, between certain temperature limits at
least, after the equation H2 + O2 = H2O2, that is, with the preliminary
formation of hydrogen peroxide, which then breaks down into water and
oxygen, and further, above all, to the fact that this substance results
from oxygen and water at high temperatures with great velocity, though
indeed only in small quantities.

The view now suggests itself, that, for example, in the combustion of
carbon monoxide at moderately high temperatures, the reaction

  (I.)        2CO + O2 = 2CO2

advances with imperceptible speed, but that on the contrary the two
stages

  (II.)           2H2O + O2 = 2H2O2,

  (III.)    2CO + 2H2O2 = 2CO2 + 2H2O,

which together result in (I.), proceed rapidly even at moderate
temperatures.

_Temperature and Reaction-Velocity._--There are few natural constants
which undergo so marked a change with temperature as those of the
velocities of chemical changes. As a rule a rise of temperature of 10°
causes a twofold or threefold rise of reaction-velocity.

If the reaction-coefficient k, in the sense of the equation derived
above, viz. k = t^{-1} log [a/(a-x)], be determined for the inversion of
cane-sugar by an acid of given concentration, the following values are
obtained:--

  Temperature = 25°  40°  45°  50°  55°
       k      = 9.7  73   139  268  491;

here a rise of temperature of only 30° suffices to raise the speed of
inversion fifty times.

We possess no adequate explanation of this remarkable temperature
influence; but some account of it is given by the molecular theory,
according to which the energy of that motion of substances in
homogeneous gaseous or liquid systems which constitutes heat increases
with the temperature, and hence also the frequency of collision of the
reacting substances. When we reflect that the velocity of motion of the
molecules of gases, and in all probability those of liquids also, are
proportional to the square root of the absolute temperature, and
therefore rise by only 1/6% per degree at room-temperature, and that we
must assume the number of collisions proportional to the velocity of the
molecules, we cannot regard the actually observed increase of
reaction-velocity, which often amounts to 10 or 12% per degree, as
exclusively due to the quickening of the molecular motion by heat. It is
more probable that the increase of the kinetic energy of the atomic
motions within the molecule itself is of significance here, as the rise
of the specific heat of gases with temperature seems to show. The change
of the reaction-coefficient k with temperature may be represented by the
empirical equation log k = -AT^{-1} + B + CT, where A, B, C are positive
constants. For low temperatures the influence of the last term is as a
rule negligible, whilst for high temperatures the first term on the
right side plays a vanishingly small part.

_Definition of Chemical Affinity._--We have still to discuss the
question of what is to be regarded as the measure of chemical affinity.
Since we are not in a position to measure directly the intensity of
chemical forces, the idea suggests itself to determine the strength of
chemical affinity from the amount of the work which the corresponding
reaction is able to do. To a certain extent the evolution of heat
accompanying the reaction is a measure of this work, and attempts have
been made to measure chemical affinities thermo-chemically, though it
may be easily shown that this definition was not well chosen. For when,
as is clearly most convenient, affinity is so defined that it determines
under all circumstances the direction of chemical change, the above
definition fails in so far as chemical processes often take place with
absorption of heat, that is, contrary to affinities so defined. But even
in those cases in which the course of the reaction at first proceeds in
the sense of the evolution of heat, it is often observed that the
reaction advances not to completion but to a certain equilibrium, or, in
other words, stops before the evolution of heat is complete.

A definition free from this objection is supplied by the second law of
thermodynamics, in accordance with which all processes must take place
in so far as they are able to do external work. When therefore we
identify chemical affinity with the maximum work which can be gained
from the process in question, we reach such a definition that the
direction of the process is under all conditions determined by the
affinity. Further, this definition has proved serviceable in so far as
the maximum work in many cases may be experimentally measured, and
moreover it stands in a simple relation to the equilibrium constant K.
Thermodynamics teaches that the maximum work A may be expressed as A =
RT log K, when R denotes the gas-constant, T the absolute temperature.
In this it is further assumed that both the molecular species produced
as well as those that disappear are present in unit concentration. The
simplest experimental method of directly determining chemical affinity
consists in the measurement of electromotive force. The latter at once
gives us the work which can be gained when the corresponding galvanic
element supplies the electricity, and, since the chemical exchange of
one gram-equivalent from Faraday's law requires 96,540 coulombs, we
obtain from the product of this number and the electromotive force the
work per gram-equivalent in watt-seconds, and this quantity when
multiplied by O.23872 is obtained in terms of the usual unit, the
gram-calorie. Experience teaches that, especially when we have to deal
with strong affinities, the affinity so determined is for the most part
almost the same as the heat-evolution, whilst in the case in which only
solid or liquid substances in the pure state take part in the reaction
at low temperatures, heat-evolution and affinity appear to possess a
practically identical value.

Hence it seems possible to calculate equilibria for low temperatures
from heats of reaction, by the aid of the two equations

  A = Q, A = RT log K;

and since the change of A with temperature, as required by the
principles of thermodynamics, follows from the specific heats of the
reacting substances, it seems further possible to calculate chemical
equilibria from heats of reaction and specific heats. The circumstance
that chemical affinity and heat-evolution so nearly coincide at low
temperatures may be derived from the hypothesis that chemical processes
are the result of forces of attraction between the atoms of the
different elements. If we may disregard the kinetic energy of the atoms,
and this is legitimate for low temperatures, it follows that both
heat-evolution and chemical affinity are merely equal to the decrease of
the potential energy of the above-mentioned forces, and it is at once
clear that the evolution of heat during a reaction between only pure
solid or pure liquid substances possesses special importance.

More complicated is the case in which gases or dissolved substances take
part. This is simplified if we first consider the mixing of two mutually
chemically indifferent gases. Thermodynamics teaches that external work
may be gained by the mere mixing of two such gases (see DIFFUSION), and
these amounts of work, which assume very considerable proportions at
high temperatures, naturally affect the value of the maximum work and so
also of the affinity, in that they always come into play when gases or
solutions react. While therefore we regard as chemical affinity in the
strictest sense the decrease of potential energy of the forces acting
between the atoms, it is clear that the quantities here involved exhibit
the simplest relations under the experimental conditions just given, for
when only substances in a pure state take part in a reaction, all mixing
of different kinds of molecules is excluded; moreover, the circumstance
that the respective substances are considered at very low temperatures
reduces the quantities of energy absorbed as kinetic energy by their
molecules to the smallest possible amount.

_Chemical Resistance._--When we know the chemical affinity of a
reaction, we are in a position to decide in which direction the process
must advance, but, unless we know the reaction-velocity also, we can in
many cases say nothing as to whether or not the reaction in question
will progress with a practically inappreciable velocity so that apparent
chemical indifference is the result. This question may be stated in the
light of the law of mass-action briefly as follows:--From a knowledge of
the chemical affinity we can calculate the equilibrium, i.e. the
numerical value of the constant K = k/k'; but to be completely informed
of the process we must know not only the ratio of the two
velocity-constants k and k', but also the separate absolute values of
the same.

In many respects the following view is more comprehensive, though
naturally in harmony with the one just expressed. Since the chemical
equilibrium is periodically attained, it follows that, as in the case of
the motion of a body or of the diffusion of a dissolved substance, it
must be opposed by very great friction. In all these cases the velocity
of the process at every instant is directly proportional to the
driving-force and inversely proportional to the frictional resistance.
We hence arrive at the result that an equation of the form

  _reaction-velocity = chemical force/chemical resistance_

must also hold for chemical change; here we have an analogy with Ohm's
law. The "chemical force" at every instant may be calculated from the
maximum work (affinity); as yet little is known about "chemical
resistance," but it is not improbable that it may be directly measured
or theoretically deduced. The problem of the calculation of chemical
reaction-velocity in absolute measure would then be solved; so far we
possess indeed only a few general facts concerning the magnitude of
chemical resistance. It is immeasurably small at ordinary temperatures
for ion-reactions, and, on the other hand, fairly large for nearly all
reactions in which carbon-bonds must be loosened (so-called "inertia of
the carbon-bond") and possesses very high values for most gas-reactions
also. With rising temperature it always strongly diminishes; on the
other hand, at very low temperatures its values are always enormous, and
at the absolute zero of temperature may be infinitely great. Therefore
at that temperature all reactions cease, since the denominator in the
above expression assumes enormous values.

It is a very remarkable phenomenon that the chemical resistance is often
small in the case of precisely those reactions in which the affinity is
also small; to this circumstance is to be traced the fact that in many
chemical changes the most stable condition is not at once reached, but
is preceded by the formation of more or less unstable intermediate
products. Thus the unstable ozone is very often first formed on the
evolution of oxygen, whilst in the reaction between oxygen and hydrogen
water is often not at once formed, but first the unstable hydrogen
peroxide as an intermediate product.

Let us now consider the chemical process in the light of the equation

  _reaction-velocity = chemical force/chemical resistance._

Thermodynamics shows that at very low temperatures, i.e. in the
immediate vicinity of the absolute zero, there is no equilibrium, but
every chemical process advances to completion in the one or the other
direction. The chemical forces therefore act in the one direction
towards complete consumption of the reacting substance. But since the
chemical resistance is now immensely great, they can produce practically
no appreciable result.

At higher temperatures the reaction always proceeds, at least in
homogeneous systems, to a certain equilibrium, and as the chemical
resistance now has finite values this equilibrium will always finally be
reached after a longer or shorter time. Finally, at very high
temperatures the chemical resistance is in every case very small, and
the equilibrium is almost instantaneously reached; at the same time, the
affinity of the reaction, as in the case of the mutual affinity between
oxygen and hydrogen, may very strongly diminish, and we have then
chemical indifference again, not because, as at low temperatures, the
denominator of the previous expression becomes very great, but because
the numerator now assumes vanishingly small values.      (W. N.)



CHEMISTRY (formerly "chymistry"; Gr. [Greek: chymeia]; for derivation
see ALCHEMY), the natural science which has for its province the study
of the composition of substances. In common with physics it includes the
determination of properties or characters which serve to distinguish one
substance from another, but while the physicist is concerned with
properties possessed by all substances and with processes in which the
molecules remain intact, the chemist is restricted to those processes in
which the molecules undergo some change. For example, the physicist
determines the density, elasticity, hardness, electrical and thermal
conductivity, thermal expansion, &c.; the chemist, on the other hand,
investigates changes in composition, such as may be effected by an
electric current, by heat, or when two or more substances are mixed. A
further differentiation of the provinces of chemistry and physics is
shown by the classifications of matter. To the physicist matter is
presented in three leading forms--solids, liquids and gases; and
although further subdivisions have been rendered necessary with the
growth of knowledge the same principle is retained, namely, a
classification based on properties having no relation to composition.
The fundamental chemical classification of matter, on the other hand,
recognizes two groups of substances, namely, _elements_, which are
substances not admitting of analysis into other substances, and
_compounds_, which do admit of analysis into simpler substances and also
of synthesis from simpler substances. Chemistry and physics, however,
meet on common ground in a well-defined branch of science, named
physical chemistry, which is primarily concerned with the correlation of
physical properties and chemical composition, and, more generally, with
the elucidation of natural phenomena on the molecular theory.

  It may be convenient here to state how the whole subject of chemistry
  is treated in this edition of the _Encyclopaedia Britannica_. The
  present article includes the following sections:--

  I. _History._--This section is confined to tracing the general trend
  of the science from its infancy to the foundations of the modern
  theory. The history of the alchemical period is treated in more detail
  in the article ALCHEMY, and of the iatrochemical in the article
  MEDICINE. The evolution of the notion of elements is treated under
  ELEMENT; the molecular hypothesis of matter under MOLECULE; and the
  genesis of, and deductions from, the atomic theory of Dalton receive
  detailed analysis in the article ATOM.

  II. _Principles._--This section treats of such subjects as
  nomenclature, formulae, chemical equations, chemical change and
  similar subjects. It is intended to provide an introduction,
  necessarily brief, to the terminology and machinery of the chemist.


  III. _Inorganic Chemistry._--Here is treated the history of
  descriptive inorganic chemistry; reference should be made to the
  articles on the separate elements for an account of their preparation,
  properties, &c.

  IV. _Organic Chemistry._--This section includes a brief history of the
  subject, and proceeds to treat of the principles underlying the
  structure and interrelations of organic compounds.

  V. _Analytical Chemistry._--This section treats of the qualitative
  detection and separation of the metals, and the commoner methods
  employed in quantitative analysis. The analysis of organic compounds
  is also noticed.

  VI. _Physical Chemistry._--This section is restricted to an account of
  the relations existing between physical properties and chemical
  composition. Other branches of this subject are treated in the
  articles CHEMICAL ACTION; ENERGETICS; SOLUTION; ALLOYS;
  THERMOCHEMISTRY.


I. HISTORY

  Greek philosophy.

Although chemical actions must have been observed by man in the most
remote times, and also utilized in such processes as the extraction of
metals from their ores and in the arts of tanning and dyeing, there is
no evidence to show that, beyond an unordered accumulation of facts, the
early developments of these industries were attended by any real
knowledge of the nature of the processes involved. All observations were
the result of accident or chance, or possibly in some cases of
experimental trial, but there is no record of a theory or even a general
classification of the phenomena involved, although there is no doubt
that the ancients had a fair knowledge of the properties and uses of the
commoner substances. The origin of chemistry is intimately bound up with
the arts which we have indicated; in this respect it is essentially an
experimental science. A unifying principle of chemical and physical
changes was provided by metaphysical conceptions of the structure of
matter. We find the notion of "elements," or primary qualities, which
confer upon all species of matter their distinctive qualities by
appropriate combination, and also the doctrine that matter is composed
of minute discrete particles, prevailing in the Greek schools. These
"elements," however, had not the significance of the elements of to-day;
they connoted physical appearances or qualities rather than chemical
relations; and the atomic theory of the ancients is a speculation based
upon metaphysical considerations, having, in its origin, nothing in
common with the modern molecular theory, which was based upon
experimentally observed properties of gases (see ELEMENT; MOLECULE).


  Alchemy.

Although such hypotheses could contribute nothing directly to the
development of a science which laid especial claim to experimental
investigations, yet indirectly they stimulated inquiry into the nature
of the "essence" with which the four "elements" were associated. This
_quinta essentia_ had been speculated upon by the Greeks, some regarding
it as immaterial or aethereal, and others as material; and a school of
philosophers termed alchemists arose who attempted the isolation of this
essence. The existence of a fundamental principle, unalterable and
indestructible, prevailing alike through physical and chemical changes,
was generally accepted. Any change which a substance may chance to
undergo was simply due to the discarding or taking up of some proportion
of the primary "elements" or qualities: of these coverings "water,"
"air," "earth" and "fire" were regarded as clinging most tenaciously to
the essence, while "cold," "heat," "moistness" and "dryness" were more
easily cast aside or assumed. Several origins have been suggested for
the word alchemy, and there seems to have been some doubt as to the
exact nature and import of the alchemical doctrines. According to M.P.E.
Berthelot, "alchemy rested partly on the industrial processes of the
ancient Egyptians, partly on the speculative theories of the Greek
philosophers, and partly on the mystical reveries of the Gnostics and
Alexandrians." The search for this essence subsequently resolved itself
into the desire to effect the transmutation of metals, more especially
the base metals, into silver and gold. It seems that this secondary
principle became the dominant idea in alchemy, and in this sense the
word is used in Byzantine literature of the 4th century; Suidas, writing
in the 11th century, defines chemistry as the "preparation of silver
and gold" (see ALCHEMY).

From the Alexandrians the science passed to the Arabs, who made
discoveries and improved various methods of separating substances, and
afterwards, from the 11th century, became seated in Europe, where the
alchemical doctrines were assiduously studied until the 15th and 16th
centuries. It is readily understood why men imbued with the authority of
tradition should prosecute the search for a substance which would confer
unlimited wealth upon the fortunate discoverer. Some alchemists honestly
laboured to effect the transmutation and to discover the "philosopher's
stone," and in many cases believed that they had achieved success, if we
may rely upon writings assigned to them. The period, however, is one of
literary forgeries; most of the MSS. are of uncertain date and
authorship, and moreover are often so vague and mystical that they are
of doubtful scientific value, beyond reflecting the tendencies of the
age. The retaining of alchemists at various courts shows the high
opinion which the doctrines had gained. It is really not extraordinary
that Isaac Hollandus was able to indicate the method of the preparation
of the "philosopher's stone" from "adamic" or "virgin" earth, and its
action when medicinally employed; that in the writings assigned to Roger
Bacon, Raimon Lull, Basil Valentine and others are to be found the exact
quantities of it to be used in transmutation; and that George Ripley, in
the 15th century, had grounds for regarding its action as similar to
that of a ferment.

In the view of some alchemists, the ultimate principles of matter were
Aristotle's four elements; the proximate constituents were a "sulphur"
and a "mercury," the father and mother of the metals; gold was supposed
to have attained to the perfection of its nature by passing in
succession through the forms of lead, brass and silver; gold and silver
were held to contain very pure red sulphur and white quicksilver,
whereas in the other metals these materials were coarser and of a
different colour. From an analogy instituted between the healthy human
being and gold, the most perfect of the metals, silver, mercury, copper,
iron, lead and tin, were regarded in the light of lepers that required
to be healed.


  Iatrochemistry.

Notwithstanding the false idea which prompted the researches of the
alchemists, many advances were made in descriptive chemistry, the metals
and their salts receiving much attention, and several of our important
acids being discovered. Towards the 16th century the failure of the
alchemists to achieve their cherished purpose, and the general increase
of medical knowledge, caused attention to be given to the utilization of
chemical preparations as medicines. As early as the 15th century the
alchemist Basil Valentine had suggested this application, but the great
exponent of this doctrine was Paracelsus, who set up a new definition:
"The true use of chemistry is not to make gold but to prepare
medicines." This relation of chemistry to medicine prevailed until the
17th century, and what in the history of chemistry is termed the
iatrochemical period (see MEDICINE) was mainly fruitful in increasing
the knowledge of compounds; the contributions to chemical theory are of
little value, the most important controversies ranging over the nature
of the "elements," which were generally akin to those of Aristotle,
modified so as to be more in accord with current observations. At the
same time, however, there were many who, opposed to the Paracelsian
definition of chemistry, still laboured at the problem of the
alchemists, while others gave much attention to the chemical industries.
Metallurgical operations, such as smelting, roasting and refining, were
scientifically investigated, and in some degree explained, by Georg
Agricola and Carlo Biringuiccio; ceramics was studied by Bernard
Palissy, who is also to be remembered as an early worker in agricultural
chemistry, having made experiments on the effect of manures on soils and
crops; while general technical chemistry was enriched by Johann Rudolf
Glauber.[1]


  Boyle.

The second half of the 17th century witnessed remarkable transitions and
developments in all branches of natural science, and the facts
accumulated by preceding generations during their generally unordered
researches were replaced by a co-ordination of experiment and deduction.
From the mazy and incoherent alchemical and iatrochemical doctrines, the
former based on false conceptions of matter, the latter on erroneous
views of life processes and physiology, a new science arose--the study
of the composition of substances. The formulation of this definition of
chemistry was due to Robert Boyle. In his _Sceptical Chemist_ (1662) he
freely criticized the prevailing scientific views and methods, with the
object of showing that true knowledge could only be gained by the
logical application of the principles of experiment and deduction.
Boyle's masterly exposition of this method is his most important
contribution to scientific progress. At the same time he clarified the
conception of elements and compounds, rejecting the older notions, the
four elements of the "vulgar Peripateticks" and the three principles of
the "vulgar Stagyrists," and defining an element as a substance
incapable of decomposition, and a compound as composed of two or more
elements. He explained chemical combination on the hypotheses that
matter consisted of minute corpuscles, that by the coalescence of
corpuscles of different substances distinctly new corpuscles of a
compound were formed, and that each corpuscle had a certain affinity for
other corpuscles.


  Phlogistic theory.

Although Boyle practised the methods which he expounded, he was unable
to gain general acceptance of his doctrine of elements; and, strangely
enough, the theory which next dominated chemical thought was an
alchemical invention, and lacked the lucidity and perspicuity of Boyle's
views. This theory, named the phlogistic theory, was primarily based
upon certain experiments on combustion and calcination, and in effect
reduced the number of the alchemical principles, while setting up a new
one, a principle of combustibility, named phlogiston (from [Greek:
phlogistos], burnt). Much discussion had centred about fire or the
"igneous principle." On the one hand, it had been held that when a
substance was burned or calcined, it combined with an "air"; on the
other hand, the operation was supposed to be attended by the destruction
or loss of the igneous principle. Georg Ernst Stahl, following in some
measure the views held by Johann Joachim Becher, as, for instance, that
all combustibles contain a "sulphur" (which notion is itself of older
date than Becher's _terra pinguis_), regarded all substances as capable
of resolution into two components, the inflammable principle phlogiston,
and another element--"water," "acid" or "earth." The violence or
completeness of combustion was proportional to the amount of phlogiston
present. Combustion meant the liberation of phlogiston. Metals on
calcination gave calces from which the metals could be recovered by
adding phlogiston, and experiment showed that this could generally be
effected by the action of coal or carbon, which was therefore regarded
as practically pure phlogiston; the other constituent being regarded as
an acid. At the hands of Stahl and his school, the phlogistic theory, by
exhibiting a fundamental similarity between all processes of combustion
and by its remarkable flexibility, came to be a general theory of
chemical action. The objections of the antiphlogistonists, such as the
fact that calces weigh more than the original metals instead of less as
the theory suggests, were answered by postulating that phlogiston was a
principle of levity, or even completely ignored as an accident, the
change of _qualities_ being regarded as the only matter of importance.
It is remarkable that this theory should have gained the esteem of the
notable chemists who flourished in the 18th century. Henry Cavendish, a
careful and accurate experimenter, was a phlogistonist, as were J.
Black, K. W. Scheele, A. S. Marggraf, J. Priestley and many others who
might be mentioned.


  Lavoisier.

Descriptive chemistry was now assuming considerable proportions; the
experimental inquiries suggested by Boyle were being assiduously
developed; and a wealth of observations was being accumulated, for the
explanation of which the resources of the dominant theory were sorely
taxed. To quote Antoine Laurent Lavoisier, "... chemists have turned
phlogiston into a vague principle, ... which consequently adapts itself
to all the explanations for which it may be required. Sometimes this
principle has weight, and sometimes it has not; sometimes it is free
fire and sometimes it is fire combined with the earthy element;
sometimes it passes through the pores of vessels, sometimes these are
impervious to it; it explains both causticity and non-causticity,
transparency and opacity, colours and their absence; it is a veritable
Proteus changing in form at each instant." Lavoisier may be justly
regarded as the founder of modern or quantitative chemistry. First and
foremost, he demanded that the balance must be used in all
investigations into chemical changes. He established as fundamental that
combustion and calcination were attended by an increase of weight, and
concluded, as did Jean Rey and John Mayow in the 17th century, that the
increase was due to the combination of the metal with the air. The
problem could obviously be completely solved only when the composition
of the air, and the parts played by its components, had been determined.
At all times the air had received attention, especially since van
Helmont made his far-reaching investigations on gases. Mayow had
suggested the existence of two components, a _spiritus nitroaerus_ which
supported combustion, and a _spiritus nitri acidi_ which extinguished
fire; J. Priestley and K. W. Scheele, although they isolated oxygen,
were fogged by the phlogistic tenets; and H. Cavendish, who had isolated
the nitrogen of the atmosphere, had failed to decide conclusively what
had really happened to the air which disappeared during combustion.

Lavoisier adequately recognized and acknowledged how much he owed to the
researches of others; to himself is due the co-ordination of these
researches, and the welding of his results into a doctrine to which the
phlogistic theory ultimately succumbed. He burned phosphorus in air
standing over mercury, and showed that (1) there was a limit to the
amount of phosphorus which could be burned in the confined air, (2) that
when no more phosphorus could be burned, one-fifth of the air had
disappeared, (3) that the weight of the air lost was nearly equal to the
difference in the weights of the white solid produced and the phosphorus
burned, (4) that the density of the residual air was less than that of
ordinary air. The same results were obtained with lead and tin; and a
more elaborate repetition indubitably established their correctness. He
also showed that on heating mercury calx alone an "air" was liberated
which differed from other "airs," and was slightly heavier than ordinary
air; moreover, the weight of the "air" set free from a given weight of
the calx was equal to the weight taken up in forming the calx from
mercury, and if the calx be heated with charcoal, the metal was
recovered and a gas named "fixed air," the modern carbon dioxide, was
formed. The former experiment had been performed by Scheele and
Priestley, who had named the gas "phlogisticated air"; Lavoisier
subsequently named it oxygen, regarding it as the "acid producer"
([Greek: oxys], sour). The theory advocated by Lavoisier came to
displace the phlogistic conception; but at first its acceptance was
slow. Chemical literature was full of the phlogistic modes of
expression--oxygen was "dephlogisticated air," nitrogen "phlogisticated
air," &c.--and this tended to retard its promotion. Yet really the
transition from the one theory to the other was simple, it being only
necessary to change the "addition or loss of phlogiston" into the "loss
or addition of oxygen." By his insistence upon the use of the balance as
a quantitative check upon the masses involved in all chemical reactions,
Lavoisier was enabled to establish by his own investigations and the
results achieved by others the principle now known as the "conservation
of mass." Matter can neither be created nor destroyed; however a
chemical system be changed, the weights before and after are equal.[2]
To him is also due a rigorous examination of the nature of elements and
compounds; he held the same views that were laid down by Boyle, and with
the same prophetic foresight predicted that some of the elements which
he himself accepted might be eventually found to be compounds.


  Chemical Affinity.

It is unnecessary in this place to recapitulate the many results which
had accumulated by the end of the 18th century, or to discuss the
labours and theories of individual workers since these receive attention
under biographical headings; in this article only the salient features
in the history of our science can be treated. The beginning of the 19th
century was attended by far-reaching discoveries in the nature of the
composition of compounds. Investigations proceeded in two
directions:--(1) the nature of chemical affinity, (2) the laws of
chemical combination. The first question has not yet been solved,
although it has been speculated upon from the earliest times. The
alchemists explained chemical action by means of such phrases as "like
attracts like," substances being said to combine when one "loved" the
other, and the reverse when it "hated" it. Boyle rejected this
terminology, which was only strictly applicable to intelligent beings;
and he used the word "affinity" as had been previously done by Stahl and
others. The modern sense of the word, viz. the force which holds
chemically dissimilar substances together (and also _similar_ substances
as is seen in di-, tri-, and poly-atomic molecules), was introduced by
Hermann Boerhaave, and made more precise by Sir Isaac Newton. The laws
of chemical combination were solved, in a measure, by John Dalton, and
the solution expressed as Dalton's "atomic theory." Lavoisier appears to
have assumed that the composition of every chemical compound was
constant, and the same opinion was the basis of much experimental
inquiry at the hands of Joseph Louis Proust during 1801 to 1809, who
vigorously combated the doctrine of Claude Louis Berthollet (_Essai de
statique chimique_, 1803), viz. that fixed proportions of elements and
compounds combine only under exceptional conditions, the general rule
being that the composition of a compound may vary continuously between
certain limits.[3]


  Dalton.

This controversy was unfinished when Dalton published the first part of
his _New System of Chemical Philosophy_ in 1808, although the _per
saltum_ theory was the most popular. Led thereto by speculations on
gases, Dalton assumed that matter was composed of atoms, that in the
elements the atoms were simple, and in compounds complex, being composed
of elementary atoms. Dalton furthermore perceived that the same two
elements or substances may combine in different proportions, and showed
that these proportions had always a simple ratio to one another. This is
the "law of multiple proportions." He laid down the following arbitrary
rules for determining the number of atoms in a compound:--if only one
compound of two elements exists, it is a binary compound and its atom is
composed of one atom of each element; if two compounds exist one is
binary (say A + B) and the other ternary (say A + 2B); if three, then
one is binary and the others may be ternary (A + 2B, and 2A + B), and so
on. More important is his deduction of equivalent weights, i.e. the
relative weights of atoms. He took hydrogen, the lightest substance
known, to be the standard. From analyses of water, which he regarded as
composed of one atom of hydrogen and one of oxygen, he deduced the
relative weight of the oxygen atom to be 6.5; from marsh gas and
olefiant gas he deduced carbon = 5, there being one atom of carbon and
two of hydrogen in the former and one atom of hydrogen to one of carbon
in the latter; nitrogen had an equivalent of 5, and so on.[4]

The value of Dalton's generalizations can hardly be overestimated,
notwithstanding the fact that in several cases they needed correction.
The first step in this direction was effected by the co-ordination of
Gay Lussac's observations on the combining volumes of gases. He
discovered that gases always combined in volumes having simple ratios,
and that the volume of the product had a simple ratio to the volumes of
the reacting gases. For example, one volume of oxygen combined with two
of hydrogen to form two volumes of steam, three volumes of hydrogen
combined with one of nitrogen to give two volumes of ammonia, one volume
of hydrogen combined with one of chlorine to give two volumes of
hydrochloric acid. An immediate inference was that the Daltonian "atom"
must have parts which enter into combination with parts of other atoms;
in other words, there must exist two orders of particles, viz. (1)
particles derived by limiting _mechanical_ subdivision, the modern
_molecule_, and (2) particles derived from the first class by _chemical_
subdivision, i.e. particles which are incapable of existing alone, but
may exist in combination. Additional evidence as to the structure of the
molecule was discussed by Avogadro in 1811, and by Ampere in 1814. From
the gas-laws of Boyle and J.A.C. Charles--viz. equal changes in
temperature and pressure occasion equal changes in equal volumes of all
gases and vapours--Avogadro deduced the law:--Under the same conditions
of temperature and pressure, equal volumes of gases contain equal
numbers of molecules; and he showed that the relative weights of the
molecules are determined as the ratios of the weights of equal volumes,
or densities. He established the existence of molecules and atoms as we
have defined above, and stated that the number of atoms in the molecule
is generally 2, but may be 4, 8, &c. We cannot tell whether his choice
of the powers of 2 is accident or design.


  Berzelius.

Notwithstanding Avogadro's perspicuous investigation, and a similar
exposition of the atom and molecule by A. M. Ampere, the views therein
expressed were ignored both by their own and the succeeding generation.
In place of the relative molecular weights, attention was concentrated
on relative atomic or equivalent weights. This may be due in some
measure to the small number of gaseous and easily volatile substances
then known, to the attention which the study of the organic compounds
received, and especially to the energetic investigations of J. J.
Berzelius, who, fired with enthusiasm by the original theory of Dalton
and the law of multiple proportions, determined the equivalents of
combining ratios of many elements in an enormous number of compounds.[5]
He prosecuted his labours in this field for thirty years; as proof of
his industry it may be mentioned that as early as 1818 he had determined
the combining ratios of about two thousand simple and compound
substances.


  Chemical notation.

  We may here notice the important chemical symbolism or notation
  introduced by Berzelius, which greatly contributed to the definite and
  convenient representation of chemical composition and the tracing of
  chemical reactions. The denotation of elements by symbols had been
  practised by the alchemists, and it is interesting to note that the
  symbols allotted to the well-known elements are identical with the
  astrological symbols of the sun and the other members of the solar
  system. Gold, the most perfect metal, had the symbol of the Sun, [*];
  silver, the semiperfect metal, had the symbol of the Moon, [*];
  copper, iron and antimony, the imperfect metals of the gold class, had
  the symbols of Venus [*], Mars [*], and the Earth [*]; tin and lead,
  the imperfect metals of the silver class, had the symbols of Jupiter
  [*], and Saturn [*]; while mercury, the imperfect metal of both the
  gold and silver class, had the symbol of the planet, [*]. Torbern Olof
  Bergman used an elaborate system in his _Opuscula physica et chemica_
  (1783); the elements received symbols composed of circles, arcs of
  circles, and lines, while certain class symbols, such as [*] for
  metals, [*] for acids, [*] for alkalies, [*] for salts, [*] for
  calces, &c., were used. Compounds were represented by copulating
  simpler symbols, e.g. mercury calx was [*][*].[6] Bergman's symbolism
  was obviously cumbrous, and the system used in 1782 by Lavoisier was
  equally abstruse, since the forms gave no clue as to composition; for
  instance water, oxygen, and nitric acid were [*], [*], and [*].

  A partial clarification was suggested in 1787 by J.H. Hassenfratz and
  Adet, who assigned to each element a symbol, and to each compound a
  sign which should record the elements present and their relative
  quantities. Straight lines and semicircles were utilized for the
  non-metallic elements, carbon, nitrogen, phosphorus and sulphur (the
  "simple acidifiable bases" of Lavoisier), and circles enclosing the
  initial letters of their names for the metals. The "compound
  acidifiable bases," i.e. the hypothetical radicals of acids, were
  denoted by squares enclosing the initial letter of the base; an alkali
  was denoted by a triangle, and the particular alkali by inserting the
  initial letter. Compounds were denoted by joining the symbols of the
  components, and by varying the manner of joining compounds of the same
  elements were distinguished. The symbol \/ was used to denote a
  liquid, and a vertical line to denote a gas. As an example of the
  complexity of this system we may note the five oxides of nitrogen,
  which were symbolized as

    [*], [*], [*], [*], and [*],

  the first three representing the gaseous oxides, and the last two the
  liquid oxides.

  A great advance was made by Dalton, who, besides introducing simpler
  symbols, regarded the symbol as representing not only the element or
  compound but also one atom of that element or compound; in other
  words, his symbol denoted equivalent weights.[7] This system, which
  permitted the correct representation of molecular composition, was
  adopted by Berzelius in 1814, who, having replaced the geometric signs
  of Dalton by the initial letter (or letters) of the Latin names of the
  elements, represented a compound by placing a _plus_ sign between the
  symbols of its components, and the number of atoms of each component
  (except in the case of only one atom) by placing Arabic numerals
  before the symbols; for example, copper oxide was Cu+O, sulphur
  trioxide S+3O. If two compounds combined, the + signs of the free
  compounds were discarded, and the number of atoms denoted by an Arabic
  index placed after the elements, and from these modified symbols the
  symbol of the new compound was derived in the same manner as simple
  compounds were built up from their elements. Thus copper sulphate was
  CuO + SO³, potassium sulphate 2SO³ + PoO² (the symbol Po for potassium
  was subsequently discarded in favour of K from _kalium_). At a later
  date Berzelius denoted an oxide by dots, equal in number to the number
  of oxygen atoms present, placed over the element; this notation
  survived longest in mineralogy. He also introduced barred symbols,
  i.e. letters traversed by a horizontal bar, to denote the double atom
  (or molecule). Although the system of Berzelius has been modified and
  extended, its principles survive in the modern notation.


  Extension of the atomic theory.

In the development of the atomic theory and the deduction of the atomic
weights of elements and the formulae of compounds, Dalton's arbitrary
rules failed to find complete acceptance. Berzelius objected to the
hypothesis that if two elements form only one compound, then the atoms
combine one and one; and although he agreed with the adoption of simple
rules as a first attempt at representing a compound, he availed himself
of other data in order to gain further information as to the structure
of compounds. For example, at first he represented ferrous and ferric
oxides by the formulae FeO2, FeO3, and by the analogy of zinc and other
basic oxides he regarded these substances as constituted similarly to
FeO2, and the acidic oxides alumina and chromium oxide as similar to
FeO3. He found, however, that chromic acid, which he had represented as
CrO6, neutralized a base containing 1/3 the quantity of oxygen. He
inferred that chromic acid must contain only three atoms of oxygen, as
did sulphuric acid SO3; consequently chromic oxide, which contains half
the amount of oxygen, must be Cr2O3, and hence ferric oxide must be
Fe2O3. The basic oxides must have the general formula MO. To these
results he was aided by the law of isomorphism formulated by E.
Mitscherlich in 1820; and he confirmed his conclusions by showing the
agreement with the law of atomic heat formulated by Dulong and Petit in
1819.

While successfully investigating the solid elements and their compounds
gravimetrically, Berzelius was guilty of several inconsistencies in his
views on gases. He denied that gaseous atoms could have parts, although
compound gases could. This attitude was due to his adherence to the
"dualistic theory" of the structure of substances, which he deduced from
electrochemical researches. From the behaviour of substances on
electrolysis (q.v.) he assumed that all substances had two components,
one bearing a negative charge, the other a positive charge. Combination
was associated with the coalescence of these charges, and the nature of
the resulting compound showed the nature of the residual electricity.
For example, positive iron combined with negative oxygen to form
positive ferrous oxide; positive sulphur combined with negative oxygen
to form negative sulphuric acid; positive ferrous oxide combined with
negative sulphuric acid to form neutral ferrous sulphate. Berzelius
elevated this theory to an important position in the history of our
science. He recognized that if an elementary atom had parts, his theory
demanded that these parts should carry different electric charges when
they entered into reaction, and the products of the reaction should vary
according as a positive or negative atom entered into combination. For
instance if the reaction 2H2 + O2 = H2O + H2O be true, the molecules of
water should be different, for a negative oxygen atom would combine in
one case, and a positive oxygen atom in the other. Hence the gaseous
atoms of hydrogen and oxygen could not have parts. A second
inconsistency was presented when he was compelled by the researches of
Dumas to admit Avogadro's hypothesis; but here he would only accept it
for the elementary gases, and denied it for other substances. It is to
be noticed that J.B. Dumas did not adopt the best methods for
emphasizing his discoveries. His terminology was vague and provoked
caustic criticism from Berzelius; he assumed that all molecules
contained two atoms, and consequently the atomic weights deduced from
vapour density determinations of sulphur, mercury, arsenic, and
phosphorus were quite different from those established by gravimetric
and other methods.

Chemists gradually tired of the notion of atomic weights on account of
the uncertainty which surrounded them; and the suggestion made by W.H.
Wollaston as early as 1814 to deal only with "equivalents," i.e. the
amount of an element which can combine with or replace unit weight of
hydrogen, came into favour, being adopted by L. Gmelin in his famous
text-book.


  Atomic and molecular weights.

Simultaneously with this discussion of the atom and molecule, great
controversy was ranging over the constitution of compounds, more
particularly over the carbon or organic compounds. This subject is
discussed in section IV., _Organic Chemistry_.The gradual accumulation
of data referring to organic compounds brought in its train a revival of
the discussion of atoms and molecules. A. Laurent and C.F. Gerhardt
attempted a solution by investigating chemical reactions. They assumed
the atom to be the smallest part of matter which can exist in
combination, and the molecule to be the smallest part which can enter
into a chemical reaction. Gerhardt found that reactions could be best
followed if one assumed the molecular weight of an element or compound
to be that weight which occupied the same volume as two unit weights of
hydrogen, and this assumption led him to double the equivalents accepted
by Gmelin, making H = 1, O = 16, and C = 12, thereby agreeing with
Berzelius, and also to halve the values given by Berzelius to many
metals. Laurent generally agreed, except when the theory compelled the
adoption of formulae containing fractions of atoms; in such cases he
regarded the molecular weight as the weight occupying a volume equal to
four unit weights of hydrogen. The bases upon which Gerhardt and Laurent
founded their views were not sufficiently well grounded to lead to the
acceptance of their results; Gerhardt himself returned to Gmelin's
equivalents in his _Lehrbuch der Chemie_ (1853) as they were in such
general use.

In 1860 there prevailed such a confusion of hypotheses as to the atom
and molecule that a conference was held at Karlsruhe to discuss the
situation. At the conclusion of the sitting, Lothar Meyer obtained a
paper written by Stanislas Cannizzaro in 1858 wherein was found the
final link required for the determination of atomic weights. This link
was the full extension of Avogadro's theory to all substances,
Cannizzaro showing that chemical reactions in themselves would not
suffice. He chose as his unit of reference the weight of an atom of
hydrogen, i.e. the weight contained in a molecule of hydrochloric acid,
thus differing from Avogadro who chose the weight of a hydrogen
molecule. From a study of the free elements Cannizzaro showed that an
element may have more than one molecular weight; for example, the
molecular weight of sulphur varied with the temperature. And from the
study of compounds he showed that each element occurred in a definite
weight or in some multiple of this weight. He called this proportion the
"atom," since it invariably enters compounds without division, and the
weight of this atom is the atomic weight. This generalization was of
great value inasmuch as it permitted the deduction of the atomic weight
of a non-gasifiable element from a study of the densities of its
gasifiable compounds.


  Valency.

From the results obtained by Laurent and Gerhardt and their predecessors
it immediately followed that, while an element could have but one atomic
weight, it could have several equivalent weights. From a detailed study
of organic compounds Gerhardt had promulgated a "theory of types" which
represented a fusion of the older radical and type theories. This theory
brought together, as it were, the most varied compounds, and stimulated
inquiry into many fields. According to this theory, an element in a
compound had a definite saturation capacity, an idea very old in itself,
being framed in the law of multiple proportions. These saturation
capacities were assiduously studied by Sir Edward Frankland, who from
the investigation, not of simple inorganic compounds, but of the
organo-metallic derivatives, determined the kernel of the theory of
valency. Frankland showed that any particular element preferentially
combined with a definite number (which might vary between certain
limits) of other atoms; for example, some atoms always combined with one
atom of oxygen, some with two, while with others two atoms entered into
combination with one of oxygen. If an element or radical combined with
one atom of hydrogen, it was termed monovalent; if with two (or with one
atom of oxygen, which is equivalent to two atoms of hydrogen) it was
divalent, and so on. The same views were expressed by Cannizzaro, and
also by A.W. von Hofmann, who materially helped the acceptance of the
doctrine by the lucid exposition in his _Introduction to Modern
Chemistry_, 1865.

The recognition of the quadrivalency of carbon by A. Kekulé was the
forerunner of his celebrated benzene theory in particular, and of the
universal application of structural formulae to the representation of
the most complex organic compounds equally lucidly as the representation
of the simplest salts. Alexander Butlerow named the "structure theory,"
and contributed much to the development of the subject. He defined
structure "as the manner of the mutual linking of the atoms in the
molecule," but denied that any such structure could give information as
to the orientation of the atoms in space. He regarded the chemical
properties of a substance as due to (1) the chemical atoms composing it,
and (2) the structure, and he asserted that while different compounds
might have the same components (isomerism), yet only one compound could
have a particular structure. Identity in properties necessitated
identity in structure.

While the principle of varying valency laid down by Frankland is still
retained, Butlerow's view that structure had no spatial significance has
been modified. The researches of L. Pasteur, J.A. Le Bel, J.
Wislicenus, van't Hoff and others showed that substances having the same
graphic formulae vary in properties and reactions, and consequently the
formulae need modification in order to exhibit these differences. Such
isomerism, named stereoisomerism (q.v.), has been assiduously developed
during recent years; it prevails among many different classes of organic
compounds and many examples have been found in inorganic chemistry.


  Periodic law.

The theory of valency as a means of showing similarity of properties and
relative composition became a dominant feature of chemical theory, the
older hypotheses of types, radicals, &c. being more or less discarded.
We have seen how its utilization in the "structure theory" permitted
great clarification, and attempts were not wanting for the deduction of
analogies or a periodicity between elements. Frankland had recognized
the analogies existing between the chemical properties of nitrogen,
phosphorus, arsenic and antimony, noting that they act as tri- or
penta-valent. Carbon was joined with silicon, zirconium and titanium,
while boron, being trivalent, was relegated to another group. A general
classification of elements, however, was not realized by Frankland, nor
even by Odling, who had also investigated the question from the valency
standpoint. The solution came about by arranging the elements in the
order of their atomic weights, tempering the arrangement with the
results deduced from the theory of valencies and experimental
observations. Many chemists contributed to the establishment of such a
periodicity, the greatest advances being made by John Newlands in
England, Lothar Meyer in Germany, and D.J. Mendeléeff in St Petersburg.
For the development of this classification see ELEMENT.


  Summary.

In the above sketch we have briefly treated the history of the main
tendencies of our science from the earliest times to the establishment
of the modern laws and principles. We have seen that the science took
its origin in the arts practised by the Egyptians, and, having come
under the influence of philosophers, it chose for its purpose the
isolation of the _quinta essentia_, and subsequently the "art of making
gold and silver." This spirit gave way to the physicians, who regarded
"chemistry as the art of preparing medicines," a denotation which in
turn succumbed to the arguments of Boyle, who regarded it as the
"science of the composition of substances," a definition which
adequately fits the science to-day. We have seen how his classification
of substances into elements and compounds, and the definitions which he
assigned to these species, have similarly been retained; and how
Lavoisier established the law of the "conservation of mass," overthrew
the prevailing phlogistic theory, and became the founder of modern
chemistry by the overwhelming importance which he gave to the use of the
balance. The development of the atomic theory and its concomitants--the
laws of chemical combination and the notion of atoms and equivalents--at
the hands of Dalton and Berzelius, the extension to the modern theory of
the atom and molecule, and to atomic and molecular weights by Avogadro,
Ampère, Dumas, Laurent, Gerhardt, Cannizzaro and others, have been
noted. The structure of the molecule, which mainly followed
investigations in organic compounds, Frankland's conception of valency,
and finally the periodic law, have also been shown in their
chronological order. The principles outlined above constitute the
foundations of our science; and although it may happen that experiments
may be made with which they appear to be not in complete agreement, yet
in general they constitute a body of working hypotheses of inestimable
value.

_Chemical Education._--It is remarkable that systematic instruction in
the theory and practice of chemistry only received earnest attention in
our academic institutions during the opening decades of the 19th
century. Although for a long time lecturers and professors had been
attached to universities, generally their duties had also included the
study of physics, mineralogy and other subjects, with the result that
chemistry received scanty encouragement. Of practical instruction there
was none other than that to be gained in a few private laboratories and
in the shops of apothecaries. The necessity for experimental
demonstration and practical instruction, in addition to academic
lectures, appears to have been urged by the French chemists L.N.
Vauquelin, Gay Lussac, Thénard, and more especially by A.F. Fourcroy and
G.F. Rouelle, while in England Humphry Davy expounded the same idea in
the experimental demonstrations which gave his lectures their brilliant
charm. But the real founder of systematic instruction in our science was
Justus von Liebig, who, having accepted the professorship at Giessen in
1824, made his chemical laboratory and course of instruction the model
of all others. He emphasized that the practical training should include
(1) the qualitative and quantitative analysis of mixtures, (2) the
preparation of substances according to established methods, (3) original
research--a course which has been generally adopted. The pattern set by
Liebig at Giessen was adopted by F. Wöhler at Göttingen in 1836, by R.W.
Bunsen at Marburg in 1840, and by O.L. Erdmann at Leipzig in 1843; and
during the 'fifties and 'sixties many other laboratories were founded. A
new era followed the erection of the laboratories at Bonn and Berlin
according to the plans of A.W. von Hofmann in 1867, and of that at
Leipzig, designed by Kolbe in 1868. We may also mention the famous
laboratory at Munich designed by A. von Baeyer in 1875.

In Great Britain the first public laboratory appears to have been opened
in 1817 by Thomas Thomson at Glasgow. But the first important step in
providing means whereby students could systematically study chemistry
was the foundation of the College of Chemistry in 1845. This institution
was taken over by the Government in 1853, becoming the Royal College of
Chemistry, and incorporated with the Royal School of Mines; in 1881 the
names were changed to the Normal School of Science and Royal School of
Mines, and again in 1890 to the Royal College of Science. In 1907 it was
incorporated in the Imperial College of Science and Technology. Under
A.W. von Hofmann, who designed the laboratories and accepted the
professorship in 1845 at the instigation of Prince Albert, and under his
successor (in 1864) Sir Edward Frankland, this institution became one of
the most important centres of chemical instruction. Oxford and Cambridge
sadly neglected the erection of convenient laboratories for many years,
and consequently we find technical schools and other universities having
a far better equipment and offering greater facilities. In the provinces
Victoria University at Manchester exercised the greater impetus,
numbering among its professors Sir W.H. Perkin and Sir Henry Roscoe.

In America public laboratory instruction was first instituted at Yale
College during the professorship of Benjamin Silliman. To the great
progress made in recent years F.W. Clarke, W. Gibbs, E.W. Morley, Ira
Remsen, and T.W. Richards have especially contributed.

In France the subject was almost entirely neglected until late in the
19th century. The few laboratories existing in the opening decades were
ill-fitted, and the exorbitant fees constituted a serious bar to general
instruction, for these institutions received little government support.
In 1869 A. Wurtz reported the existence of only _one_ efficient
laboratory in France, namely the École Normale Supérieure, under the
direction of H. Sainte Claire Deville. During recent years chemistry has
become one of the most important subjects in the curriculum of technical
schools and universities, and at the present time no general educational
institution is complete until it has its full equipment of laboratories
and lecture theatres.

  _Chemical Literature_.--The growth of chemical literature since the
  publication of Lavoisier's famous _Traité de chimie_ in 1789, and of
  Berzelius' _Lehrbuch der Chemie_ in 1808-1818, has been enormous.
  These two works, and especially the latter, were the models followed
  by Thénard, Liebig, Strecker, Wöhler and many others, including Thomas
  Graham, upon whose _Elements of Chemistry_ was founded Otto's famous
  _Lehrbuch der Chemie_, to which H. Kopp contributed the general
  theoretical part, Kolbe the organic, and Buff and Zamminer the
  physico-chemical. Organic chemistry was especially developed by the
  publication of Gerhardt's _Traité de chimie organique_ in 1853-1856,
  and of Kekulé's _Lehrbuch der organischen Chemie_ in 1861-1882.
  General theoretical and physical chemistry was treated with
  conspicuous acumen by Lothar Meyer in his _Moderne Theorien_, by W.
  Ostwald in his _Lehrbuch der allgem. Chemie_ (1884-1887), and by
  Nernst in his _Theoretische Chemie_. In English, Roscoe and
  Schorlemmer's _Treatise on Chemistry_ is a standard work; it records
  a successful attempt to state the theories and facts of chemistry,
  not in condensed epitomes, but in an easily read form. The _Traité de
  chimie minérale_, edited by H. Moissan, and the _Handbuch der
  anorganischen Chemie_, edited by Abegg, are of the same type. O.
  Dammer's _Handbuch der anorganischen Chemie_ and F. Beilstein's
  _Handbuch der organischen Chemie_ are invaluable works of reference.
  Of the earlier encyclopaedias we may notice the famous _Handwörterbuch
  der reinen und angewandten Chemie_, edited by Liebig; Frémy's
  _Encyclopédie de chimie_, Wurtz's _Dictionnaire de chimie pure et
  appliquée_, Watts' _Dictionary of Chemistry_, and Ladenburg's
  _Handwörterbuch der Chemie_.

  The number of periodicals devoted to chemistry has steadily increased
  since the early part of the 19th century. In England the most
  important is the _Journal of the Chemical Society of London_, first
  published in 1848. Since 1871 abstracts of papers appearing in the
  other journals have been printed. In 1904 a new departure was made in
  issuing _Annual Reports_, containing résumés of the most important
  researches of the year. The _Chemical News_, founded by Sir W. Crookes
  in 1860, may also be noted. In America the chief periodical is the
  _American Chemical Journal_, founded in 1879. Germany is provided with
  a great number of magazines. The _Berichte der deutschen chemischen
  Gesellschaft_, published by the Berlin Chemical Society, the
  _Chemisches Centralblatt_, which is confined to abstracts of papers
  appearing in other journals, the _Zeitschrift für Chemie_, and
  Liebig's _Annalen der Chemie_ are the most important of the general
  magazines. Others devoted to special phases are the _Journal für
  praktische Chemie_, founded by Erdmann in 1834, the _Zeitschrift für
  anorganische Chemie_ and the _Zeitschrift für physikalische Chemie_.
  Mention may also be made of the invaluable _Jahresberichte_ and the
  _Jahrbuch der Chemie_. In France, the most important journals are the
  _Annales de chimie et de physique_, founded in 1789 with the title
  _Annales de chimie_, and the _Comptes rendus_, published weekly by the
  Académie française since 1835.


II. GENERAL PRINCIPLES

The substances with which the chemist has to deal admit of
classification into elements and compounds. Of the former about eighty
may be regarded as well characterized, although many more have been
described.

_Elements._--The following table gives the names, symbols and atomic
weights of the perfectly characterized elements:--

  _International Atomic Weights_, 1910.

                         Atomic                           Atomic
    Name.     Symbol.   Weights.      Name.     Symbol.   Weights.
                          O=16.                            O=16.
  Aluminium      Al      27.1        Mercury        Hg     200.0
  Antimony       Sb     120.2        Molybdenum     Mo      96.0
  Argon          A       39.9        Neodymium      Nd     144.3
  Arsenic        As      74.96       Neon           Ne      20
  Barium         Ba     137.37       Nickel         Ni      58.68
  Beryllium or   Be}      9.1        Nitrogen       N       14.01
    Glucinum     Gl}                 Osmium         Os     190.9
  Bismuth        Bi     208.0        Oxygen         O       16.00
  Boron          B       11.0        Palladium      Pd     106.7
  Bromine        Br      79.92       Phosphorus     P       31.0
  Cadmium        Cd     112.40       Platinum       Pt     195.0
  Caesium        Cs     132.81       Potassium      K       39.10
  Calcium        Ca      40.09       Praseodymium   Pr     140.6
  Carbon         C       12.0        Radium         Ra     226.4
  Cerium         Ce     140.25       Rhodium        Rh     102.9
  Chlorine       Cl      35.46       Rubidium       Rb      85.45
  Chromium       Cr      52.0        Ruthenium      Ru     101.7
  Cobalt         Co      58.97       Samarium       Sa     150.4
  Columbium      Cb}     93.5        Scandium       Sc      44.1
    or Niobium   Nb}                 Selenium       Se      79.2
  Copper         Cu      63.57       Silicon        Si      28.3
  Dysprosium     Dy     162.5        Silver         Ag     107.88
  Erbium         Er     167.4        Sodium         Na      23.0
  Europium       Eu     152.0        Strontium      Sr       87.62
  Fluorine       F       19.0        Sulphur        S        32.07
  Gadolinium     Gd     157.3        Tantalum       Ta      181.0
  Gallium        Ga      69.9        Tellurium      Te      127.5
  Germanium      Ge      72.5        Terbium        Tb      159.2
  Gold           Au     197.2        Thallium       Tl      204.0
  Helium         He       4.0        Thorium        Th      232.42
  Hydrogen       H        1.008      Thulium        Tm      168.5
  Indium         In     114.8        Tin            Sn      119.0
  Iodine         I      126.92       Titanium       Ti       48.1
  Iridium        Ir     193.1        Tungsten       W       184.0
  Iron           Fe      55.85       Uranium        U       238.5
  Krypton        Kr      83.0        Vanadium       V        51.2
  Lanthanum      La     139.0        Xenon          Xe      130.7
  Lead           Pb     207.10       Ytterbium      Yb      172
  Lithium        Li       7.00         (Neoytterbium)
  Lutecium       Lu     174          Yttrium        Y        89.0
  Magnesium      Mg      24.32       Zinc           Zn       65.37
  Manganese      Mn      54.93       Zirconium      Zr       90.6

The elements are usually divided into two classes, the metallic and the
non-metallic elements; the following are classed as non-metals, and the
remainder as metals:--

  Hydrogen    Oxygen      Boron       Neon
  Chlorine    Sulphur     Carbon      Krypton
  Bromine     Selenium    Silicon     Xenon
  Iodine      Tellurium   Phosphorus  Helium
  Fluorine    Nitrogen    Argon

Of these hydrogen, chlorine, fluorine, oxygen, nitrogen, argon, neon,
krypton, xenon and helium are gases, bromine is a liquid, and the
remainder are solids. All the metals are solids at ordinary temperatures
with the exception of mercury, which is liquid. The metals are mostly
bodies of high specific gravity; they exhibit, when polished, a peculiar
brilliancy or metallic lustre, and they are good conductors of heat and
electricity; the non-metals, on the other hand, are mostly bodies of low
specific gravity, and bad conductors of heat and electricity, and do not
exhibit metallic lustre. The non-metallic elements are also sometimes
termed metalloids, but this appellation, which signifies metal-like
substances (Gr. [Greek: eidos], like), strictly belongs to certain
elements which do not possess the properties of the true metals,
although they more closely resemble them than the non-metals in many
respects; thus, selenium and tellurium, which are closely allied to
sulphur in their chemical properties, although bad conductors of heat
and electricity, exhibit metallic lustre and have relatively high
specific gravities. But when the properties of the elements are
carefully contrasted together it is found that no strict line of
demarcation can be drawn dividing them into two classes; and if they are
arranged in a series, those which are most closely allied in properties
being placed next to each other, it is observed that there is a more or
less regular alteration in properties from term to term in the series.

When binary compounds, or compounds of two elements, are decomposed by
an electric current, the two elements make their appearance at opposite
poles. Those elements which are disengaged at the negative pole are
termed electro-positive, or positive, or basylous elements, whilst those
disengaged at the positive pole are termed electro-negative, or
negative, or chlorous elements. But the difference between these two
classes of elements is one of degree only, and they gradually merge into
each other; moreover the electric relations of elements are not
absolute, but vary according to the state of combination in which they
exist, so that it is just as impossible to divide the elements into two
classes according to this property as it is to separate them into two
distinct classes of metals and non-metals. The following, however, are
negative towards the remaining elements which are more or less
positive:--Fluorine, chlorine, bromine, iodine, oxygen, sulphur,
selenium, tellurium.

The metals may be arranged in a series according to their power of
displacing one another in salt solutions, thus Cs, Rb, K, Na, Mg, Al,
Mn, Zn, Cd, Tl, Fe, Co, Ni, Sn, Pb, (H), Sb, Bi, As, Cu, Hg, Ag, Pd, Pt,
Au.

Elements which readily enter into reaction with each other, and which
develop a large amount of heat on combination, are said to have a
powerful affinity for each other. The tendency of positive elements to
unite with positive elements, or of negative elements to unite with
negative elements, is much less than that of positive elements to unite
with negative elements, and the greater the difference in properties
between two elements the more powerful is their affinity for each other.
Thus, the affinity of hydrogen and oxygen for each other is extremely
powerful, much heat being developed by the combination of these two
elements; when binary compounds of oxygen are decomposed by the electric
current, the oxygen invariably appears at the positive pole, being
negative to all other elements, but the hydrogen of hydrogen compounds
is always disengaged at the negative pole. Hydrogen and oxygen are,
therefore, of very opposite natures, and this is well illustrated by the
circumstance that oxygen combines, with very few exceptions, with all
the remaining elements, whilst compounds of only a limited number with
hydrogen have been obtained.

_Compounds._--A chemical compound contains two or more elements;
consequently it should be possible to analyse it, i.e. separate it into
its components, or to synthesize it, i.e. build it up from its
components. In general, a compound has properties markedly different
from those of the elements of which it is composed.

_Laws of Chemical Combination._--A _molecule_ may be defined as the
smallest part of a substance which can exist alone; an _atom_ as the
smallest part of a substance which can exist in combination. The
molecule of every compound must obviously contain at least two atoms,
and generally the molecules of the elements are also polyatomic, the
elements with monatomic molecules (at moderate temperatures) being
mercury and the gases of the argon group. The laws of chemical
combination are as follows:--

1. _Law of Definite Proportions._--The same compound always contains the
same elements combined together in the same mass proportion. Silver
chloride, for example, in whatever manner it may be prepared, invariably
consists of chlorine and silver in the proportions by weight of 35.45
parts of the former and 107.93 of the latter.

2. _Law of Multiple Proportions._--When the same two elements combine
together to form more than one compound, the different masses of one of
the elements which unite with a constant mass of the other, bear a
simple ratio to one another. Thus, 1 part by weight of hydrogen unites
with 8 parts by weight of oxygen, forming water, and with 16 or 8 x 2
parts of oxygen, forming hydrogen peroxide. Again, in nitrous oxide we
have a compound of 8 parts by weight of oxygen and 14 of nitrogen; in
nitric oxide a compound of 16 or 8 x 2 parts of oxygen and 14 of
nitrogen; in nitrous anhydride a compound of 24 or 8 x 3 parts of oxygen
and 14 of nitrogen; in nitric peroxide a compound of 32 or 8 x 4 parts
of oxygen and 14 of nitrogen; and lastly, in nitric anhydride a compound
of 40 or 8 x 5 parts of oxygen and 14 of nitrogen.

3. _Law of Reciprocal Proportions._--The masses of different elements
which combine separately with one and the same mass of another element,
are either the same as, or simple multiples of, the masses of these
different elements which combine with each other. For instance, 35.45
parts of chlorine and 79.96 parts of bromine combine with 107.93 parts
of silver; and when chlorine and bromine unite it is in the proportion
of 35.45 parts of the former to 79.96 parts of the latter. Iodine unites
with silver in the proportion of 126.97 parts to 107.93 parts of the
latter, but it combines with chlorine in two proportions, viz. in the
proportion of 126.97 parts either to 35.45 or to three times 35.45 parts
of chlorine.

There is a fourth law of chemical combination which only applies to
gases. This law states that:--gases combine with one another in simple
proportions by volume, and the volume of the product (if gaseous) has a
simple ratio to the volumes of the original mixtures; in other words,
the densities of gases are simply related to their combining weights.

_Nomenclature._--If a compound contains two atoms it is termed a binary
compound, if three a ternary, if four a quaternary, and so on. Its
systematic name is formed by replacing the last syllable of the
electro-negative element by _ide_ and prefixing the name of the other
element. For example, compounds of oxygen are _oxides_, of chlorine,
_chlorides_, and so on. If more than one compound be formed from the
same two elements, the difference is shown by prefixing such words as
mono-, di-, tri-, sesqui-, per-, sub-, &c., to the last part of the
name, or the suffixes -_ous_ and -_ic_ may be appended to the name of
the first element. For example take the oxides of nitrogen, N2O, NO,
N2O3, NO2, N2O5; these are known respectively as nitrous oxide, nitric
oxide, nitrogen trioxide, nitrogen peroxide and nitrogen pentoxide. The
affixes -_ous_ and _sub_- refer to the compounds containing more of the
positive element, -_ic_ and _per_- to those containing less.

An _acid_ (q.v.) is a compound of hydrogen, which element can be
replaced by metals, the hydrogen being liberated, giving substances
named _salts_. An _alkali_ or _base_ is a substance which neutralizes an
acid with the production of salts but with no evolution of hydrogen. A
base may be regarded as water in which part of the hydrogen is replaced
by a metal, or by a radical which behaves as a metal. (The term
_radical_ is given to a group of atoms which persist in chemical
changes, behaving as if the group were an element; the commonest is the
ammonium group, NH4, which forms salts similar to the salts of sodium
and potassium.) If the acid contains no oxygen it is a _hydracid_, and
its systematic name is formed from the prefix _hydro_- and the name of
the other element or radical, the last syllable of which has been
replaced by the termination -_ic_. For example, the acid formed by
hydrogen and chlorine is termed hydrochloric acid (and sometimes
hydrogen chloride). If an acid contains oxygen it is termed an
_oxyacid_. The nomenclature of acids follows the same general lines as
that for binary compounds. If one acid be known its name is formed by
the termination -_ic_, e.g. carbonic acid; if two, the one containing
the less amount of oxygen takes the termination _-ous_ and the other the
termination -_ic_, e.g. nitrous acid, HNO2, nitric acid, HNO3. If more
than two be known, the one inferior in oxygen content has the prefix
_hypo_- and the termination -_ous_, and the one superior in oxygen
content has the prefix _per_- and the termination -_ic_. This is
illustrated in the four oxyacids of chlorine, HClO, HClO2, HClO3, HClO4,
which have the names hypochlorous, chlorous, chloric and perchloric
acids. An acid is said to be monobasic, dibasic, tribasic, &c.,
according to the number of replaceable hydrogen atoms; thus HNO3 is
monobasic, sulphuric acid H2SO4 dibasic, phosphoric acid H3PO4 tribasic.

An acid terminating in -_ous_ forms a salt ending in -_ite_, and an
oxyacid ending in -_ic_ forms a salt ending in -_ate_. Thus the chlorine
oxyacids enumerated above form salts named respectively hypochlorites,
chlorites, chlorates and perchlorates. Salts formed from hydracids
terminate in -_ide_, following the rule for binary compounds. An _acid_
salt is one in which the whole amount of hydrogen has not been replaced
by metal; a _normal_ salt is one in which all the hydrogen has been
replaced; and a _basic_ salt is one in which part of the acid of the
normal salt has been replaced by oxygen.

_Chemical Formulae._--Opposite the name of each element in the second
column of the above table, the symbol is given which is always employed
to represent it. This symbol, however, not only represents the
particular element, but a certain definite quantity of it. Thus, the
letter H always stands for 1 atom or 1 part by weight of hydrogen, the
letter N for 1 atom or 14 parts of nitrogen, and the symbol Cl for 1
atom or 35.5 parts of chlorine.[8] Compounds are in like manner
represented by writing the symbols of their constituent elements side by
side, and if more than one atom of each element be present, the number
is indicated by a numeral placed on the right of the symbol of the
element either below or above the line. Thus, hydrochloric acid is
represented by the formula HCl, that is to say, it is a compound of an
atom of hydrogen with an atom of chlorine, or of 1 part by weight of
hydrogen with 35.5 parts by weight of chlorine; again, sulphuric acid is
represented by the formula H2SO4, which is a statement that it consists
of 2 atoms of hydrogen, 1 of sulphur, and 4 of oxygen, and consequently
of certain relative weights of these elements. A figure placed on the
right of a symbol only affects the symbol to which it is attached, but
when figures are placed in front of several symbols all are affected by
it, thus 2H2SO4 means H2SO4 taken twice.

The distribution of weight in chemical change is readily expressed in
the form of equations by the aid of these symbols; the equation

  2HCl + Zn = ZnCl2 + H2,

for example, is to be read as meaning that from 73 parts of hydrochloric
acid and 65 parts of zinc, 136 parts of zinc chloride and 2 parts of
hydrogen are produced. The + sign is invariably employed in this way
either to express combination or action upon, the meaning usually
attached to the use of the sign = being that from such and such bodies
such and such other bodies are formed.

Usually, when the symbols of the elements are written or printed with a
figure to the right, it is understood that this indicates a molecule of
the element, the symbol alone representing an atom. Thus, the symbols H2
and P4 indicate that the molecules of hydrogen and phosphorus
respectively contain 2 and 4 atoms. Since, according to the molecular
theory, in all cases of chemical change the action is between molecules,
such symbols as these ought always to be employed. Thus, the formation
of hydrochloric acid from hydrogen and chlorine is correctly represented
by the equation

  H2 + Cl2 = 2HCl;

that is to say, a molecule of hydrogen and a molecule of chlorine give
rise to two molecules of hydrochloric acid; whilst the following
equation merely represents the relative weights of the elements which
enter into reaction, and is not a complete expression of what is
supposed to take place:--

  H + Cl = HCl.

In all cases it is usual to represent substances by formulae which to
the best of our knowledge express their molecular composition in the
state of gas, and not merely the relative number of atoms which they
contain; thus, acetic acid consists of carbon, hydrogen and oxygen in
the proportion of one atom of carbon, two of hydrogen, and one of
oxygen, but its molecular weight corresponds to the formula C2H4O2,
which therefore is always employed to represent acetic acid. When
chemical change is expressed with the aid of molecular formulae not only
is the distribution of weight represented, but by the mere inspection of
the symbols it is possible to deduce from the law of gaseous combination
mentioned above, the relative volumes which the agents and resultants
occupy in the state of gas if measured at the same temperature and under
the same pressure. Thus, the equation

  2H2 + O2= 2H2O

not only represents that certain definite weights of hydrogen and oxygen
furnish a certain definite weight of the compound which we term water,
but that if the water in the state of gas, the hydrogen and the oxygen
are all measured at the same temperature and pressure, the volume
occupied by the oxygen is only half that occupied by the hydrogen,
whilst the resulting water-gas will only occupy the same volume as the
hydrogen. In other words, 2 volumes of oxygen and 4 volumes of hydrogen
furnish 4 volumes of water-gas. A simple equation like this, therefore,
when properly interpreted, affords a large amount of information. One
other instance may be given; the equation

  2NH3 = N2 + 3H2

represents the decomposition of ammonia gas into nitrogen and hydrogen
gases by the electric spark, and it not only conveys the information
that a certain relative weight of ammonia, consisting of certain
relative weights of hydrogen and nitrogen, is broken up into certain
relative weights of hydrogen and nitrogen, but also that the nitrogen
will be contained in half the space which contained the ammonia, and
that the volume of the hydrogen will be one and a half times as great as
that of the original ammonia, so that in the decomposition of ammonia
the volume becomes doubled.

Formulae which merely express the relative number of atoms of the
different elements present in a compound are termed _empirical
formulae_, and the formulae of all compounds whose molecular weights are
undetermined are necessarily empirical. The _molecular formula_ of a
compound, however, is always a simple multiple of the empirical formula,
if not identical with it; thus, the empirical formula of acetic acid is
CH2O, and its molecular formula is C2H4O2, or twice CH2O. In addition to
empirical and molecular formulae, chemists are in the habit of employing
various kinds of rational formulae, called structural, constitutional or
graphic formulae, &c., which not only express the molecular composition
of the compounds to which they apply, but also embody certain
assumptions as to the manner in which the constituent atoms are
arranged, and convey more or less information with regard to the nature
of the compound itself, viz. the class to which it belongs, the manner
in which it is formed, and the behaviour it will exhibit under various
circumstances. Before explaining these formulae it will be necessary,
however, to consider the differences in combining power exhibited by the
various elements.

_Valency._--It is found that the number of atoms of a given element, of
chlorine, for example, which unite with an atom of each of the other
elements is very variable. Thus, hydrogen unites with but a single atom
of chlorine, zinc with two, boron with three, silicon with four,
phosphorus with five and tungsten with six. Those elements which are
equivalent in combining or displacing power to a single atom of hydrogen
are said to be _univalent_ or _monad_ elements; whilst those which are
equivalent to two atoms of hydrogen are termed bivalent or dyad
elements; and those equivalent to three, four, five or six atoms of
hydrogen triad, tetrad, pentad or hexad elements. But not only is the
combining power or valency (atomicity) of the elements different, it is
also observed that one element may combine with another in several
proportions, or that its valency may vary; for example, phosphorus forms
two chlorides represented by the formulae PCl3 and PCl5, nitrogen the
series of oxides represented by the formulae N2O, NO, (N2O3), N2O4,
N2O5, molybdenum forms the chlorides MoCl2, MoCl3, MoCl4, MoCl5,
MoCl6(?), and tungsten the chlorides WCl2, WCl4, WCl5, WCl6.

In explanation of these facts it is supposed that each element has a
certain number of "units of affinity," which may be entirely, or only in
part, engaged when it enters into combination with other elements; and
in those cases in which the entire number of units of affinity are not
engaged by other elements, it is supposed that those which are thus
disengaged neutralize each other, as it were. For example, in phosphorus
pentachloride the five units of affinity possessed by the phosphorus
atom are satisfied by the five monad atoms of chlorine, but in the
trichloride two are disengaged, and, it may be supposed, satisfy each
other. Compounds in which all the units of affinity of the contained
elements are engaged are said to be _saturated_, whilst those in which
the affinities of the contained elements are not all engaged by other
elements are said to be _unsaturated_. According to this view, it is
necessary to assume that, in all unsaturated compounds, two, or some
even number of affinities are disengaged; and also that all elements
which combine with an even number of monad atoms cannot combine with an
odd number, and vice versa,--in other words, that the number of units of
affinity active in the case of any given element must be always either
an even or an odd number, and that it cannot be at one time an even and
at another an odd number. There are, however, a few remarkable
exceptions to this "law." Thus, it must be supposed that in nitric
oxide, NO, an odd number of affinities are disengaged, since a single
atom of dyad oxygen is united with a single atom of nitrogen, which in
all its compounds with other elements acts either as a triad or pentad.
When nitric peroxide, N2O4, is converted into gas, it decomposes, and at
about 180° C. its vapour entirely consists of molecules of the
composition NO2; while at temperatures between this and 0° C. it
consists of a mixture in different proportions of the two kinds of
molecules, N2O4 and NO2. The oxide NO2 must be regarded as another
instance of a compound in which an odd number of affinities of one of
the contained elements are disengaged, since it contains two atoms of
dyad oxygen united with a single atom of triad or pentad nitrogen.
Again, when tungsten hexachloride is converted into vapour it is
decomposed into chlorine and a pentachloride, having a normal vapour
density, but as in the majority of its compounds tungsten acts as a
hexad, we apparently must regard its pentachloride as a compound in
which an odd number of free affinities are disengaged. Hitherto no
explanation has been given of these exceptions to what appears to be a
law of almost universal application, viz. that the sum of the units of
affinity of all the atoms in a compound is an even number.

The number of units of affinity active in the case of any particular
element is largely dependent, however, upon the nature of the element or
elements with which it is associated. Thus, an atom of iodine only
combines with one of hydrogen, but may unite with three of chlorine,
which never combines with more than a single atom of hydrogen; an atom
of phosphorus unites with only three atoms of hydrogen, but with five of
chlorine, or with four of hydrogen and one of iodine; and the chlorides
corresponding to the higher oxides of lead, nickel, manganese and
arsenic, PbO2, Ni2O3, MnO2 and AS2O5 do not exist as stable compounds,
but the lower chlorides, PbCl2, NiCl2, MnCl2 and AsCl3, are very stable.

The valency of an element is usually expressed by dashes or Roman
numerals placed on the right of its symbol, thus: H', O'', B''', C^{IV},
P^V, Mo^{VI}; but in constructing graphic formulae the symbols of the
elements are written with as many lines attached to each symbol as the
element which it represents has units of affinity.

The periodic law (see ELEMENT) permits a grouping of the elements
according to their valency as follows:--Group O.: helium, neon, argon,
krypton and xenon appear to be devoid of valency. Group I.: the alkali
metals Li, Na, K, Rb, Cs, and also Ag, monovalent; Cu, monovalent and
divalent; Au, monovalent and trivalent. Group II.: the alkaline earth
metals Ca, Sr, Ba, and also Be (Gl), Mg, Zn, Cd, divalent; Hg,
monovalent and divalent. Group III.: B, trivalent; Al, trivalent, but
possibly also tetra- or penta-valent; Ga, divalent and trivalent; In,
mono-, di- and tri-valent; Tl, monovalent and trivalent. Group IV.: C,
Si, Ge, Zr, Th, tetravalent; Ti, tetravalent and hexavalent; Sn, Pb,
divalent and tetravalent; Ce, trivalent and tetravalent. Group V.: N,
trivalent and pentavalent, but divalent in nitric oxide; P, As, Sb, Bi,
trivalent and pentavalent, the last being possibly divalent in BiO and
BiCl2. Group VI.: O, usually divalent, but tetravalent and possibly
hexavalent in oxonium and other salts; S, Se, Te, di-, tetra- and
hexa-valent; Cr, di-, tri- and hexa-valent; Mo, W, di-, tri-, tetra-,
penta- and hexa-valent. Group VII.: H(?), monovalent; the halogens F,
Cl, Br, I, usually monovalent, but possibly also tri- and pentavalent;
Mn, divalent and trivalent, and possibly heptavalent in permanganates.
Group VIII.: Fe, Co, divalent and trivalent; Ni, divalent; Os, Ru,
hexavalent and octavalent; Pd, Pt, divalent and tetravalent; Ir, tri-,
tetra- and hexa-valent. (See also VALENCY.)

_Constitutional Formulae._--Graphic or constitutional formulae are
employed to express the manner in which the constituent atoms of
compounds are associated together; for example, the trioxide of sulphur
is usually regarded as a compound of an atom of hexad sulphur with three
atoms of dyad oxygen, and this hypothesis is illustrated by the graphic
formula

      O
     //
  O=S
     \\
      O .

When this oxide is brought into contact with water it combines with it
forming sulphuric acid, H2SO4.

In this compound only two of the oxygen atoms are wholly associated with
the sulphur atom, each of the remaining oxygen atoms being united by one
of its affinities to the sulphur atoms, and by the remaining affinity to
an atom of hydrogen; thus--

  H·O   O
     \ //
      S
     / \\
  H·O   O .

The graphic formula of a sulphate is readily deduced by remembering that
the hydrogen atoms are partially or entirely replaced. Thus acid sodium
sulphate, normal sodium sulphate, and zinc sulphate have the formulae

  Na·O   O          Na·O   O             O   O
      \ //              \ //            / \ //
       S                 S            Zn   S
      / \\              / \\            \ / \\
   H·O   O ,        Na·O   O ,           O   O .

Again, the reactions of acetic acid, C2H4O2, show that the four atoms of
hydrogen which it contains have not all the same function, and also that
the two atoms of oxygen have different functions; the graphic formula
which we are led to assign to acetic acid, viz.

         O
    H   //
  H·C--C
    ·   \
    H    O·H

serves in a measure to express this, three of the atoms of hydrogen
being represented as associated with one of the atoms of carbon, whilst
the fourth atom is associated with an atom of oxygen which is united by
a single affinity to the second atom of carbon, to which, however, the
second atom of oxygen is united by both of its affinities. It is not to
be supposed that there are any actual _bonds_ of union between the
atoms; graphic formulae such as these merely express the hypothesis that
certain of the atoms in a compound come directly within the sphere of
attraction of certain other atoms, and only indirectly within the sphere
of attraction of others,--an hypothesis to which chemists are led by
observing that it is often possible to separate a group of elements from
a compound, and to displace it by other elements or groups of elements.

Rational formulae of a much simpler description than these graphic
formulae are generally employed. For instance, sulphuric acid is usually
represented by the formula SO2(OH)2, which indicates that it may be
regarded as a compound of the group SO2 with twice the group OH. Each of
these OH groups is equivalent in combining or displacing power to a
monad element, since it consists of an atom of dyad oxygen associated
with a single atom of monad hydrogen, so that in this case the SO2 group
is equivalent to an atom of a dyad element. This formula for sulphuric
acid, however, merely represents such facts as that it is possible to
displace an atom of hydrogen and an atom of oxygen in sulphuric acid by
a single atom of chlorine, thus forming the compound SO3HCl; and that by
the action of water on the compound SO2Cl2 twice the group OH, or water
minus an atom of hydrogen, is introduced in place of the two monad atoms
of chlorine--

  SO2Cl2 + 2HOH =  SO2(OH)2 + 2HCl.
          Water.   Sulphuric acid.

Constitutional formulae like these, in fact, are nothing more than
symbolic expressions of the character of the compounds which they
represent, the arrangement of symbols in a certain definite manner being
understood to convey certain information with regard to the compounds
represented.

Groups of two or more atoms like SO2 and OH, which are capable of
playing the part of elementary atoms (that is to say, which can be
transferred from compound to compound), are termed compound radicals,
the elementary atoms being simple radicals. Thus, the atom of hydrogen
is a monad simple radical, the atom of oxygen a dyad simple radical,
whilst the group OH is a monad compound radical.

It is often convenient to regard compounds as formed upon certain types;
alcohol, for example, may be said to be a compound formed upon the water
type, that is to say, a compound formed from water by displacing one of
the atoms of hydrogen by the group of elements C2H5, thus--

    { H        { C2H5
  O {        O {
    { H        { H
  Water      Alcohol.

Constitutional formulae become of preponderating importance when we
consider the more complicated inorganic and especially organic
compounds. Their full significance is treated in the section of this
article dealing with organic chemistry, and in the articles ISOMERISM
and STEREO-ISOMERISM.

_Chemical Action._--Chemical change or chemical action may be said to
take place whenever changes occur which involve an alteration in the
composition of molecules, and may be the result of the action of agents
such as heat, electricity or light, or of two or more elements or
compounds upon each other.

Three kinds of changes are to be distinguished, viz. changes which
involve combination, changes which involve decomposition or separation,
and changes which involve at the same time both decomposition and
combination. Changes of the first and second kind, according to our
views of the constitution of molecules, are probably of very rare
occurrence; in fact, chemical action appears almost always to involve
the occurrence of both these kinds of change, for, as already pointed
out, we must assume that the molecules of hydrogen, oxygen and several
other elements are diatomic, or that they consist of two atoms. Indeed,
it appears probable that with few exceptions the elements are all
compounds of similar atoms united together by one or more units of
affinity, according to their valencies. If this be the case, however, it
is evident that there is no real distinction between the reactions which
take place when two elements combine together and when an element in a
compound is displaced by another. The combination, as it is ordinarily
termed, of chlorine with hydrogen, and the displacement of iodine in
potassium iodide by the action of chlorine, may be cited as examples; if
these reactions are represented, as such reactions very commonly are, by
equations which merely express the relative weights of the bodies which,
enter, into reaction, and of the products, thus--

     H      +       Cl      =        HCl
  Hydrogen.      Chlorine.    Hydrochloric acid.

         KI        +     Cl     =       KCl       +        I
  Potassium iodide.   Chlorine.  Potassium chloride.    Iodine.

they appear to differ in character; but if they are correctly
represented by molecular equations, or equations which express the
relative number of molecules which enter into reaction and which result
from the reaction, it will be obvious that the character of the reaction
is substantially the same in both cases, and that both are instances of
the occurrence of what is ordinarily termed double decomposition--

    H2    +    Cl2     =      2HCl
  Hydrogen. Chlorine.   Hydrochloric acid.

         2KI      +     Cl2    =        2KCl      +     I2.
  Potassium iodide.  Chlorine.  Potassium chloride.   Iodine.

In all cases of chemical change energy in the form of heat is either
developed or absorbed, and the amount of heat developed or absorbed in a
given reaction is as definite as are the weights of the substance
engaged in the reaction. Thus, in the production of hydrochloric acid
from hydrogen and chlorine 22,000 calories are developed; in the
production of hydrobromic acid from hydrogen and bromine, however, only
844O calories are developed; and in the formation of hydriodic acid from
hydrogen and iodine 6040 calories are absorbed.

This difference in behaviour of the three elements, chlorine, bromine
and iodine, which in many respects exhibit considerable resemblance, may
be explained in the following manner. We may suppose that in the
formation of gaseous hydrochloric acid from gaseous chlorine and
hydrogen, according to the equation

  H2 + Cl2 = HCl + HCl,

a certain amount of energy is expended in separating the atoms of
hydrogen in the hydrogen molecule, and the atoms of chlorine in the
chlorine molecule, from each other; but that heat is developed by the
combination of the hydrogen atoms with the chlorine atoms, and that, as
more energy is developed by the union of the atoms of hydrogen and
chlorine than is expended in separating the hydrogen atoms from each
other and the chlorine atoms from one another, the result of the action
of the two elements upon each other is the development of heat,--the
amount finally developed in the reaction being the difference between
that absorbed in decomposing the elementary molecules and that developed
by the combination of the atoms of chlorine and hydrogen. In the
formation of gaseous hydrobromic acid from liquid bromine and gaseous
hydrogen--

  H2 + Br2 = HBr + HBr,

in addition to the energy expended in decomposing the hydrogen and
bromine molecules, energy is also expended in converting the liquid
bromine into the gaseous condition, and probably less heat is developed
by the combination of bromine and hydrogen than by the combination of
chlorine and hydrogen, so that the amount of heat finally, developed is
much less than is developed in the formation of hydrochloric acid.
Lastly, in the production of gaseous hydriodic acid from hydrogen and
solid iodine--

  H2 + I2 = HI + HI,

so much energy is expended in the decomposition of the hydrogen and
iodine molecules and in the conversion of the iodine into the gaseous
condition, that the heat which it may be supposed is developed by the
combination of the hydrogen and iodine atoms is insufficient to balance
the expenditure, and the final result is therefore negative; hence it
is necessary in forming hydriodic acid from its elements to apply heat
continuously.

These compounds also afford examples of the fact that, generally
speaking, those compounds are most readily formed, and are most stable,
in the formation of which the most heat is developed. Thus, chlorine
enters into reaction with hydrogen, and removes hydrogen from
hydrogenized bodies, far more readily than bromine; and hydrochloric
acid is a far more stable substance than hydrobromic acid, hydriodic
acid being greatly inferior even to hydrobromic acid in stability.
Compounds formed with the evolution of heat are termed exothermic, while
those formed with an absorption are termed endothermic. Explosives are
the commonest examples of endothermic compounds.

When two substances which by their action upon each other develop much
heat enter into reaction, the reaction is usually complete without the
employment of an excess of either; for example, when a mixture of
hydrogen and oxygen, in the proportions to form water--

  2H2 + O2 = 2OH2,

is exploded, it is entirely converted into water. This is also the case
if two substances are brought together in solution, by the action of
which upon each other a third body is formed which is insoluble in the
solvent employed, and which also does not tend to react upon any of the
substances present; for instance, when a solution of a chloride is added
to a solution of a silver salt, insoluble silver chloride is
precipitated, and almost the whole of the silver is removed from
solution, even if the amount of the chloride employed be not in excess
of that theoretically required.

But if there be no tendency to form an insoluble compound, Or one which
is not liable to react upon any of the other substances present, this is
no longer the case. For example, when a solution of a ferric salt is
added to a solution of potassium thiocyanate, a deep red coloration is
produced, owing to the formation of ferric thiocyanate. Theoretically
the reaction takes place in the case of ferric nitrate in the manner
represented by the equation

     Fe(NO3)3     +        3KCNS        =        Fe(CNS)3
  Ferric nitrate.  Potassium thiocyanate.   Ferric thiocyanate.

    +    3KNO3;
     Potassium nitrate.

but it is found that even when more than sixty times the amount of
potassium thiocyanate required by this equation is added, a portion of
the ferric nitrate still remains unconverted, doubtless owing to the
occurrence of the reverse change--

  Fe(CNS)3 + 3KNO3 = Fe(NO3)3 + 3KCNS.

In this, as in most other cases in which substances act upon one another
under such circumstances that the resulting compounds are free to react,
the extent to which the different kinds of action which may occur take
place is dependent upon the mass of the substances present in the
mixture. As another instance of this kind, the decomposition of bismuth
chloride by water may be cited. If a very large quantity of water be
added, the chloride is entirely decomposed in the manner represented by
the equation--

       BiCl3   +    OH2     =      BiOCl    +    2HCl,
  Bismuth chloride.          Bismuth oxychloride.

the oxychloride being precipitated; but if smaller quantities of water
be added the decomposition is incomplete, and it is found that the
extent to which decomposition takes place is proportional to the
quantity of water employed, the decomposition being incomplete, except
in presence of large quantities of water, because of the occurrence of
the reverse action--

  BiOCl + 2HCl = BiCl3 + OH2.

Chemical change which merely involves simple decomposition is thus seen
to be influenced by the masses of the reacting substances and the
presence of the products of decomposition; in other words the system of
reacting substances and resultants form a mixture in which chemical
action has apparently ceased, or the system is in equilibrium. Such
reactions are termed reversible (see CHEMICAL ACTION).


III. INORGANIC CHEMISTRY

Inorganic chemistry is concerned with the descriptive study of the
elements and their compounds, except those of carbon. Reference should
be made to the separate articles on the different elements and the more
important compounds for their preparation, properties and uses. In this
article the development of this branch of the science is treated
historically.

The earliest discoveries in inorganic chemistry are to be found in the
metallurgy, medicine and chemical arts of the ancients. The Egyptians
obtained silver, iron, copper, lead, zinc and tin, either pure or as
alloys, by smelting the ores; mercury is mentioned by Theophrastus (c.
300 B.C.). The manufacture of glass, also practised in Egypt, demanded a
knowledge of sodium or potassium carbonates; the former occurs as an
efflorescence on the shores of certain lakes; the latter was obtained
from wood ashes. Many substances were used as pigments: Pliny records
white lead, cinnabar, verdigris and red oxide of iron; and the
preparation of coloured glasses and enamels testifies to the uses to
which these and other substances were put. Salts of ammonium were also
known; while alum was used as a mordant in dyeing. Many substances were
employed in ancient medicine: galena was the basis of a valuable
Egyptian cosmetic and drug; the arsenic sulphides, realgar and orpiment,
litharge, alum, saltpetre, iron rust were also used. Among the Arabian
and later alchemists we find attempts made to collate compounds by
specific properties, and it is to these writers that we are mainly
indebted for such terms as "alkali," "sal," &c. The mineral acids,
hydrochloric, nitric and sulphuric acids, and also _aqua regia_ (a
mixture of hydrochloric and nitric acids) were discovered, and the
vitriols, alum, saltpetre, sal-ammoniac, ammonium carbonate, silver
nitrate (_lunar caustic_) became better known. The compounds of mercury
attracted considerable attention, mainly on account of their medicinal
properties; mercuric oxide and corrosive sublimate were known to
pseudo-Geber, and the nitrate and basic sulphate to "Basil Valentine."
Antimony and its compounds formed the subject of an elaborate treatise
ascribed to this last writer, who also contributed to our knowledge of
the compounds of zinc, bismuth and arsenic. All the commonly occurring
elements and compounds appear to have received notice by the alchemists;
but the writings assigned to the alchemical period are generally so
vague and indefinite that it is difficult to determine the true value of
the results obtained.

In the succeeding iatrochemical period, the methods of the alchemists
were improved and new ones devised. Glauber showed how to prepare
hydrochloric acid, _spiritus salis_, by heating rock-salt with sulphuric
acid, the method in common use to-day; and also nitric acid from
saltpetre and arsenic trioxide. Libavius obtained sulphuric acid from
many substances, e.g. alum, vitriol, sulphur and nitric acid, by
distillation. The action of these acids on many metals was also studied;
Glauber obtained zinc, stannic, arsenious and cuprous chlorides by
dissolving the metals in hydrochloric acid, compounds hitherto obtained
by heating the metals with corrosive sublimate, and consequently
supposed to contain mercury. The scientific study of salts dates from
this period, especial interest being taken in those compounds which
possessed a medicinal or technical value. In particular, the salts of
potassium, sodium and ammonium were carefully investigated, but sodium
and potassium salts were rarely differentiated.[9] The metals of the
alkaline-earths were somewhat neglected; we find Georg Agricola
considering gypsum (calcium sulphate) as a compound of lime, while
calcium nitrate and chloride became known at about the beginning of the
17th century. Antimonial, bismuth and arsenical compounds were
assiduously studied, a direct consequence of their high medicinal
importance; mercurial and silver compounds were investigated for the
same reason. The general tendency of this period appears to have taken
the form of improving and developing the methods of the alchemists; few
new fields were opened, and apart from a more complete knowledge of the
nature of salts, no valuable generalizations were attained.

The discovery of phosphorus by Brand, a Hamburg alchemist, in 1669
excited chemists to an unwonted degree; it was also independently
prepared by Robert Boyle and J. Kunckel, Brand having kept his process
secret. Towards the middle of the 18th century two new elements were
isolated: cobalt by G. Brandt in 1742, and nickel by A.F. Cronstedt in
1750. These discoveries were followed by Daniel Rutherford's isolation
of nitrogen in 1772, and by K. Scheele's isolation of chlorine and
oxygen in 1774 (J. Priestley discovered oxygen independently at about
the same time), and his investigation of molybdic and tungstic acids in
the following year; metallic molybdenum was obtained by P.J. Hjelm in
1783, and tungsten by Don Fausto d'Elhuyar; manganese was isolated by
J.G. Gahn in 1774. In 1784 Henry Cavendish thoroughly examined hydrogen,
establishing its elementary nature; and he made the far-reaching
discovery that water was composed of two volumes of hydrogen to one of
oxygen.

The phlogistic theory, which pervaded the chemical doctrine of this
period, gave rise to continued study of the products of calcination and
combustion; it thus happened that the knowledge of oxides and oxidation
products was considerably developed. The synthesis of nitric acid by
passing electric sparks through moist air by Cavendish is a famous piece
of experimental work, for in the first place it determined the
composition of this important substance, and in the second place the
minute residue of air which would not combine, although ignored for
about a century, was subsequently examined by Lord Rayleigh and Sir
William Ramsay, who showed that it consists of a mixture of elementary
substances--argon, krypton, neon and xenon (see ARGON).

The 18th century witnessed striking developments in pneumatic chemistry,
or the chemistry of gases, which had been begun by van Helmont, Mayow,
Hales and Boyle. Gases formerly considered to be identical came to be
clearly distinguished, and many new ones were discovered. Atmospheric
air was carefully investigated by Cavendish, who showed that it
consisted of two elementary constituents: nitrogen, which was isolated
by Rutherford in 1772, and oxygen, isolated in 1774; and Black
established the presence, in minute quantity, of carbon dioxide (van
Helmont's _gas sylvestre_). Of the many workers in this field, Priestley
occupies an important position. A masterly device, initiated by him, was
to collect gases over mercury instead of water; this enabled him to
obtain gases previously only known in solution, such as ammonia,
hydrochloric acid, silicon fluoride and sulphur dioxide. Sulphuretted
hydrogen and nitric oxide were discovered at about the same time.

Returning to the history of the discovery of the elements and their more
important inorganic compounds, we come in 1789 to M.H. Klaproth's
detection of a previously unknown constituent of the mineral
pitchblende. He extracted a substance to which he assigned the character
of an element, naming it uranium (from [Greek: Ouranos], heaven); but it
was afterwards shown by E.M. Péligot, who prepared the pure metal, that
Klaproth's product was really an oxide. This element was investigated at
a later date by Sir Henry Roscoe, and more thoroughly and successfully
by C. Zimmermann and Alibegoff. Pitchblende attained considerable
notoriety towards the end of the 19th century on account of two
important discoveries. The first, made by Sir William Ramsay in 1896,
was that the mineral evolved a peculiar gas when treated with sulphuric
acid; this gas, helium (q.v.), proved to be identical with a constituent
of the sun's atmosphere, detected as early as 1868 by Sir Norman Lockyer
during a spectroscopic examination of the sun's chromosphere. The second
discovery, associated with the Curies, is that of the peculiar
properties exhibited by the impure substance, and due to a constituent
named radium. The investigation of this substance and its properties
(see RADIOACTIVITY) has proceeded so far as to render it probable that
the theory of the unalterability of elements, and also the hitherto
accepted explanations of various celestial phenomena--the source of
solar energy and the appearances of the tails of comets--may require
recasting.

In the same year as Klaproth detected uranium, he also isolated zirconia
or zirconium oxide from the mineral variously known as zircon, hyacinth,
jacynth and jargoon; but he failed to obtain the metal, this being first
accomplished some years later by Berzelius, who decomposed the double
potassium zirconium fluoride with potassium. In the following year,
1795, Klaproth announced the discovery of a third new element, titanium;
its isolation (in a very impure form), as in the case of zirconium, was
reserved for Berzelius.

Passing over the discovery of carbon disulphide by W.A. Lampadius in
1796, of chromium by L.N. Vauquelin in 1797, and Klaproth's
investigation of tellurium in 1798, the next important series of
observations was concerned with platinum and the allied metals. Platinum
had been described by Antonio de Ulloa in 1748, and subsequently
discussed by H.T. Scheffer in 1752. In 1803 W.H. Wollaston discovered
palladium, especially interesting for its striking property of absorbing
("occluding") as much as 376 volumes of hydrogen at ordinary
temperatures, and 643 volumes at 90°. In the following year he
discovered rhodium; and at about the same time Smithson Tennant added
two more to the list--iridium and osmium; the former was so named from
the changing tints of its oxides ([Greek: iris], rainbow), and the
latter from the odour of its oxide ([Greek: osmê], smell). The most
recently discovered "platinum metal," ruthenium, was recognized by C.E.
Claus in 1845. The great number and striking character of the compounds
of this group of metals have formed the subject of many investigations,
and already there is a most voluminous literature. Berzelius was an
early worker in this field; he was succeeded by Bunsen, and Deville and
Debray, who worked out the separation of rhodium; and at a later date by
P.T. Cleve, the first to make a really thorough study of these elements
and their compounds. Of especial note are the curious compounds formed
by the union of carbon monoxide with platinous chloride, discovered by
Paul Schützenberger and subsequently investigated by F.B. Mylius and F.
Foerster and by Pullinger; the phosphoplatinic compounds formed
primarily from platinum and phosphorus pentachloride; and also the
"ammino" compounds, formed by the union of ammonia with the chloride,
&c., of these metals, which have been studied by many chemists,
especially S.M. Jörgensen. Considerable uncertainty existed as to the
atomic weights of these metals, the values obtained by Berzelius being
doubtful. K.F.O. Seubert redetermined this constant for platinum, osmium
and iridium; E.H. Keiser for palladium, and A.A. Joly for ruthenium.

The beginning of the 19th century witnessed the discovery of certain
powerful methods for the analysis of compounds and the isolation of
elements. Berzelius's investigation of the action of the electric
current on salts clearly demonstrated the invaluable assistance that
electrolysis could render to the isolator of elements; and the adoption
of this method by Sir Humphry Davy for the analysis of the hydrates of
the metals of the alkalis and alkaline earths, and the results which he
thus achieved, established its potency. In 1808 Davy isolated sodium and
potassium; he then turned his attention to the preparation of metallic
calcium, barium, strontium and magnesium. Here he met with greater
difficulty, and it is to be questioned whether he obtained any of these
metals even in an approximately pure form (see ELECTROMETALLURGY). The
discovery of boron by Gay Lussac and Davy in 1809 led Berzelius to
investigate silica (_silex_). In the following year he announced that
silica was the oxide of a hitherto unrecognized element, which he named
_silicium_, considering it to be a metal. This has proved to be
erroneous; it is non-metallic in character, and its name was altered to
silicon, from analogy with carbon and boron. At the same time Berzelius
obtained the element, in an impure condition, by fusing silica with
charcoal and iron in a blast furnace; its preparation in a pure
condition he first accomplished in 1823, when he invented the method of
heating double potassium fluorides with metallic potassium. The success
which attended his experiments in the case of silicon led him to apply
it to the isolation of other elements. In 1824 he obtained zirconium
from potassium zirconium fluoride; the preparation of (impure) titanium
quickly followed, and in 1828 he obtained thorium. A similar process,
and equally efficacious, was introduced by F. Wöhler in 1827. It
consisted in heating metallic chlorides with potassium, and was first
applied to aluminium, which was isolated in 1827; in the following year,
beryllium chloride was analysed by the same method, beryllium oxide
(berylla or glucina) having been known since 1798, when it was detected
by L. N. Vauquelin in the gem-stone beryl.

In 1812 B. Courtois isolated the element iodine from "kelp," the burnt
ashes of marine plants. The chemical analogy of this substance to
chlorine was quickly perceived, especially after its investigation by
Davy and Gay Lussac. Cyanogen, a compound which in combination behaved
very similarly to chlorine and iodine, was isolated in 1815 by Gay
Lussac. This discovery of the first of the then-styled "compound
radicals" exerted great influence on the prevailing views of chemical
composition. Hydrochloric acid was carefully investigated at about this
time by Davy, Faraday and Gay Lussac, its composition and the elementary
nature of chlorine being thereby established.

In 1817 F. Stromeyer detected a new metallic element, cadmium, in
certain zinc ores; it was rediscovered at subsequent dates by other
observers and its chemical resemblance to zinc noticed. In the same year
Berzelius discovered selenium in a deposit from sulphuric acid chambers,
his masterly investigation including a study of the hydride, oxides and
other compounds. Selenic acid was discovered by E. Mitscherlich, who
also observed the similarity of the crystallographic characters of
selenates and sulphates, which afforded valuable corroboration of his
doctrine of isomorphism. More recent and elaborate investigations in
this direction by A.E.H. Tutton have confirmed this view.

In 1818 L.J. Thénard discovered hydrogen dioxide, one of the most
interesting inorganic compounds known, which has since been carefully
investigated by H.E. Schöne, M. Traube, Wolfenstein and others. About
the same time, J.A. Arfvedson, a pupil of Berzelius, detected a new
element, which he named lithium, in various minerals--notably petalite.
Although unable to isolate the metal, he recognized its analogy to
sodium and potassium; this was confirmed by R. Bunsen and A. Matthiessen
in 1855, who obtained the metal by electrolysis and thoroughly examined
it and its compounds. Its crimson flame-coloration was observed by C.G.
Gmelin in 1818.

The discovery of bromine in 1826 by A.J. Balard completed for many years
Berzelius's group of "halogen" elements; the remaining member, fluorine,
notwithstanding many attempts, remained unisolated until 1886, when
Henri Moissan obtained it by the electrolysis of potassium fluoride
dissolved in hydrofluoric acid. Hydrobromic and hydriodic acids were
investigated by Gay Lussac and Balard, while hydrofluoric acid received
considerable attention at the hands of Gay Lussac, Thénard and
Berzelius. We may, in fact, consider that the descriptive study of the
various halogen compounds dates from about this time. Balard discovered
chlorine monoxide in 1834, investigating its properties and reactions;
and his observations on hypochlorous acid and hypochlorites led him to
conclude that "bleaching-powder" or "chloride of lime" was a compound or
mixture in equimolecular proportions of calcium chloride and
hypochlorite, with a little calcium hydrate. Gay Lussac investigated
chloric acid; Stadion discovered perchloric acid, since more fully
studied by G.S. Serullas and Roscoe; Davy and Stadion investigated
chlorine peroxide, formed by treating potassium chlorate with sulphuric
acid. Davy also described and partially investigated the gas, named by
him "euchlorine," obtained by heating potassium chlorate with
hydrochloric acid; this gas has been more recently examined by Pebal.
The oxy-acids of iodine were investigated by Davy and H.G. Magnus;
periodic acid, discovered by the latter, is characterized by the
striking complexity of its salts as pointed out by Kimmins.

In 1830 N.G. Sefström definitely proved the existence of a metallic
element vanadium, which had been previously detected (in 1801) in
certain lead ores by A.M. del Rio; subsequent elaborate researches by
Sir Henry Roscoe showed many inaccuracies in the conclusions of earlier
workers (for instance, the substance considered to be the pure element
was in reality an oxide) and provided science with an admirable account
of this element and its compounds. B.W. Gerland contributed to our
knowledge of vanadyl salts and the vanadic acids. Chemically related to
vanadium are the two elements tantalum and columbium or niobium. These
elements occur in the minerals columbite and tantalite, and their
compounds became known in the early part of the 19th century by the
labours of C. Hatchett, A.G. Ekeberg, W.H. Wollaston and Berzelius. But
the knowledge was very imperfect; neither was it much clarified by H.
Rose, who regarded niobium oxide as the element. The subject was revived
in 1866 by C.W. Blomstrand and J.C. Marignac, to whom is due the credit
of first showing the true chemical relations of these elements.
Subsequent researches by Sainte Claire Deville and L.J. Troost, and by
A.G. Krüss and L.E. Nilson, and subsequently (1904) by Hall, rendered
notable additions to our knowledge of these elements and their
compounds. Tantalum has in recent years been turned to economic service,
being employed, in the same manner as tungsten, for the production of
the filaments employed in incandescent electric lighting.

In 1833 Thomas Graham, following the paths already traced out by E.D.
Clarke, Gay Lussac and Stromeyer, published his masterly investigation
of the various phosphoric acids and their salts, obtaining results
subsequently employed by J. von Liebig in establishing the doctrine of
the characterization and basicity of acids. Both phosphoric and
phosphorous acids became known, although imperfectly, towards the end of
the 18th century; phosphorous acid was first obtained pure by Davy in
1812, while pure phosphorous oxide, the anhydride of phosphorous acid,
remained unknown until T.E. Thorpe's investigation of the products of
the slow combustion of phosphorus. Of other phosphorus compounds we may
here notice Gengembre's discovery of phosphuretted hydrogen (phosphine)
in 1783, the analogy of which to ammonia was first pointed out by Davy
and supported at a later date by H. Rose; liquid phosphuretted hydrogen
was first obtained by Thénard in 1838; and hypophosphorous acid was
discovered by Dulong in 1816. Of the halogen compounds of phosphorus,
the trichloride was discovered by Gay Lussac and Thénard, while the
pentachloride was obtained by Davy. The oxychloride, bromides, and other
compounds were subsequently discovered; here we need only notice
Moissan's preparation of the trifluoride and Thorpe's discovery of the
pentafluoride, a compound of especial note, for it volatilizes
unchanged, giving a vapour of normal density and so demonstrating the
stability of a pentavalent phosphorus compound (the pentachloride and
pentabromide dissociate into a molecule of the halogen element and
phosphorus trichloride).

In 1840 C.F. Schönbein investigated ozone, a gas of peculiar odour
(named from the Gr. [Greek: ozein], to smell) observed in 1785 by Martin
van Marum to be formed by the action of a silent electric discharge on
the oxygen of the air; he showed it to be an allotropic modification of
oxygen, a view subsequently confirmed by Marignac, Andrews and Soret. In
1845 a further contribution to the study of allotropy was made by Anton
Schrötter, who investigated the transformations of yellow and red
phosphorus, phenomena previously noticed by Berzelius, the inventor Of
the term "allotropy." The preparation of crystalline boron in 1856 by
Wöhler and Sainte Claire Deville showed that this element also existed
in allotropic forms, amorphous boron having been obtained simultaneously
and independently in 1809 by Gay Lussac and Davy. Before leaving this
phase of inorganic chemistry, we may mention other historical examples
of allotropy. Of great importance is the chemical identity of the
diamond, graphite and charcoal, a fact demonstrated in part by Lavoisier
in 1773, Smithson Tennant in 1706, and by Sir George Steuart-Mackenzie
(1780-1848), who showed that equal weights of these three substances
yielded the same weight of carbon dioxide on combustion. The allotropy
of selenium was first investigated by Berzelius; and more fully in 1851
by J.W. Hittorf, who carefully investigated the effects produced by
heat; crystalline selenium possesses a very striking property, viz. when
exposed to the action of light its electric conductivity increases.
Another element occurring in allotropic forms is sulphur, of which many
forms have been described. E. Mitscherlich was an early worker in this
field. A modification known as "black sulphur," soluble in water, was
announced by F.L. Knapp in 1848, and a colloidal modification was
described by H. Debus. The dynamical equilibrium between rhombic, liquid
and monosymmetric sulphur has been worked out by H.W. Bakhuis Roozeboom.
The phenomenon of allotropy is not confined to the non-metals, for
evidence has been advanced to show that allotropy is far commoner than
hitherto supposed. Thus the researches of Carey Lea, E.A. Schneider and
others, have proved the existence of "colloidal silver"; similar forms
of the metals gold, copper, and of the platinum metals have been
described. The allotropy of arsenic and antimony is also worthy of
notice, but in the case of the first element the variation is
essentially non-metallic, closely resembling that of phosphorus. The
term allotropy has also been applied to inorganic compounds, identical
in composition, but assuming different crystallographic forms. Mercuric
oxide, sulphide and iodide; arsenic trioxide; titanium dioxide and
silicon dioxide may be cited as examples.

The joint discovery in 1859 of the powerful method of spectrum analysis
(see SPECTROSCOPY) by G.R. Kirchhoff and R.W. Bunsen, and its
application to the detection and the characterization of elements when
in a state of incandescence, rapidly led to the discovery of many
hitherto unknown elements. Within two years of the invention the authors
announced the discovery of two metals, rubidium and caesium, closely
allied to sodium, potassium and lithium in properties, in the mineral
lepidolite and in the Dürkheim mineral water. In 1861 Sir William
Crookes detected thallium (named from the Gr. [Greek: thallos], a green
bud, on account of a brilliant green line in its spectrum) in the
selenious mud of the sulphuric acid manufacture; the chemical affinities
of this element, on the one hand approximating to the metals of the
alkalis, and on the other hand to lead, were mainly established by C.A.
Lamy. Of other metals first detected by the spectroscope mention is to
be made of indium, determined by F. Reich and H.T. Richter in 1863, and
of gallium, detected in certain zinc blendes by Lecoq de Boisbaudran in
1875. The spectroscope has played an all-important part in the
characterization of the elements, which, in combination with oxygen,
constitute the group of substances collectively named the "rare earths."
The substances occur, in very minute quantity, in a large number of
sparingly-distributed and comparatively rare minerals--euxenite,
samarksite, cerite, yttrotantalite, &c. Scandinavian specimens of these
minerals were examined by J. Gadolin, M.H. Klaproth, and especially by
Berzelius; these chemists are to be regarded as the pioneers in this
branch of descriptive chemistry. Since their day many chemists have
entered the lists, new and powerful methods of research have been
devised, and several new elements definitely characterized. Our
knowledge on many points, however, is very chaotic; great uncertainty
and conflict of evidence circulate around many of the "new elements"
which have been announced, so much so that P.T. Cleve proposed to divide
the "rare earth" metals into two groups, (1) "perfectly characterized";
(2) "not yet thoroughly characterized." The literature of this subject
is very large. The memorial address on J.C.G. de Marignac, a noted
worker in this field, delivered by Cleve, a high authority on this
subject, before the London Chemical Society (_J.C.S. Trans._, 1895, p.
468), and various papers in the same journal by Sir William Crookes,
Bohuslav Brauner and others should be consulted for details.

In the separation of the constituents of the complex mixture of oxides
obtained from the "rare earth" minerals, the methods generally forced
upon chemists are those of fractional precipitation or crystallization;
the striking resemblances of the compounds of these elements rarely
admitting of a complete separation by simple precipitation and
filtration. The extraordinary patience requisite to a successful
termination of such an analysis can only be adequately realized by
actual research; an idea may be obtained from Crookes's _Select Methods
in Analysis_. Of recent years the introduction of various organic
compounds as precipitants or reagents has reduced the labour of the
process; and advantage has also been taken of the fairly complex double
salts which these metals form with compounds. The purity of the
compounds thus obtained is checked by spectroscopic observations.
Formerly the spark- and absorption-spectra were the sole methods
available; a third method was introduced by Crookes, who submitted the
oxides, or preferably the basic sulphates, to the action of a negative
electric discharge _in vacuo_, and investigated the phosphorescence
induced spectroscopically. By such a study in the ultra-violet region of
a fraction prepared from crude yttria he detected a new element
victorium, and subsequently by elaborate fractionation obtained the
element itself.

The first earth of this group to be isolated (although in an impure
form) was yttria, obtained by Gadolin in 1794 from the mineral
gadolinite, which was named after its discoverer and investigator.
Klaproth and Vauquelin also investigated this earth, but without
detecting that it was a complex mixture--a discovery reserved for C.G.
Mosander. The next discovery, made independently and simultaneously in
1803 by Klaproth and by W. Hisinger and Berzelius, was of ceria, the
oxide of cerium, in the mineral cerite found at Ridderhytta,
Westmannland, Sweden. These crude earths, yttria and ceria, have
supplied most if not all of the "rare earth" metals. In 1841 Mosander,
having in 1839 discovered a new element lanthanum in the mineral cerite,
isolated this element and also a hitherto unrecognized substance,
didymia, from crude yttria, and two years later he announced the
determination of two fresh constituents of the same earth, naming them
erbia and terbia. Lanthanum has retained its elementary character, but
recent attempts at separating it from didymia have led to the view that
didymium is a mixture of two elements, praseodymium and neodymium (see
DIDYMIUM). Mosander's erbia has been shown to contain various other
oxides--thulia, holmia, &c.--but this has not yet been perfectly worked
out. In 1878 Marignac, having subjected Mosander's erbia, obtained from
gadolinite, to a careful examination, announced the presence of a new
element, ytterbium; this discovery was confirmed by Nilson, who in the
following year discovered another element, scandium, in Marignac's
ytterbia. Scandium possesses great historical interest, for Cleve showed
that it was one of the elements predicted by Mendeléeff about ten years
previously from considerations based on his periodic classification of
the elements (see ELEMENT). Other elements predicted and characterized
by Mendeléeff which have been since realized are gallium, discovered in
1875, and germanium, discovered in 1885 by Clemens Winkler.

In 1880 Marignac examined certain earths obtained from the mineral
samarskite, which had already in 1878 received attention from
Delafontaine and later from Lecoq de Boisbaudran. He established the
existence of two new elements, samarium and gadolinium, since
investigated more especially by Cleve, to whom most of our knowledge on
this subject is due. In addition to the rare elements mentioned above,
there are a score or so more whose existence is doubtful. Every year is
attended by fresh "discoveries" in this prolific source of elementary
substances, but the paucity of materials and the predilections of the
investigators militate in some measure against a just valuation being
accorded to such researches. After having been somewhat neglected for
the greater attractions and wider field presented by organic chemistry,
the study of the elements and their inorganic compounds is now rapidly
coming into favour; new investigators are continually entering the
lists; the beaten paths are being retravcrsed and new ramifications
pursued.


IV. ORGANIC CHEMISTRY

While inorganic chemistry was primarily developed through the study of
minerals--a connexion still shown by the French appellation _chimie
minérale_--organic chemistry owes its origin to the investigation of
substances occurring in the vegetable and animal organisms. The quest of
the alchemists for the philosopher's stone, and the almost general
adherence of the iatrochemists to the study of the medicinal characters
and preparation of metallic compounds, stultified in some measure the
investigation of vegetable and animal products. It is true that by the
distillation of many herbs, resins and similar substances, several
organic compounds had been prepared, and in a few cases employed as
medicines; but the prevailing classification of substances by physical
and superficial properties led to the correlation of organic and
inorganic compounds, without any attention being paid to their chemical
composition. The clarification and spirit of research so clearly
emphasized by Robert Boyle in the middle of the 17th century is
reflected in the classification of substances expounded by Nicolas
Lémery, in 1675, in his _Cours de chymie_. Taking as a basis the nature
of the source of compounds, he framed three classes: "mineral,"
comprising the metals, minerals, earths and stones; "vegetable,"
comprising plants, resins, gums, juices, &c.; and "animal," comprising
animals, their different parts and excreta. Notwithstanding the
inconsistency of his allocation of substances to the different groups
(for instance, acetic acid was placed in the vegetable class, while the
acetates and the products of their dry distillation, acetone, &c., were
placed in the mineral class), this classification came into favour. The
phlogistonists endeavoured to introduce chemical notions to support it:
Becher, in his _Physica subterranea_(1669), stated that mineral,
vegetable and animal matter contained the same elements, but that more
simple combinations prevailed in the mineral kingdom; while Stahl, in
his _Specimen Becherianum_ (1702), held the "earthy" principle to
predominate in the mineral class, and the "aqueous" and "combustible" in
the vegetable and animal classes. It thus happened that in the earlier
treatises on phlogistic chemistry organic substances were grouped with
all combustibles.

The development of organic chemistry from this time until almost the end
of the 18th century was almost entirely confined to such compounds as
had practical applications, especially in pharmacy and dyeing. A new and
energetic spirit was introduced by Scheele; among other discoveries this
gifted experimenter isolated and characterized many organic acids, and
proved the general occurrence of glycerin (_Ölsüss_) in all oils and
fats. Bergman worked in the same direction; while Rouelle was attracted
to the study of animal chemistry. Theoretical speculations were revived
by Lavoisier, who, having explained the nature of combustion and
determined methods for analysing compounds, concluded that vegetable
substances ordinarily contained carbon, hydrogen and oxygen, while
animal substances generally contained, in addition to these elements,
nitrogen, and sometimes phosphorus and sulphur. Lavoisier, to whom
chemistry was primarily the chemistry of oxygen compounds, having
developed the radical theory initiated by Guyton de Morveau, formulated
the hypothesis that vegetable and animal substances were oxides of
radicals composed of carbon and hydrogen; moreover, since simple
radicals (the elements) can form more than one oxide, he attributed the
same character to his hydrocarbon radicals: he considered, for instance,
sugar to be a neutral oxide and oxalic acid a higher oxide of a certain
radical, for, when oxidized by nitric acid, sugar yields oxalic acid. At
the same time, however, he adhered to the classification of Lémery; and
it was only when identical compounds were obtained from both vegetable
and animal sources that this subdivision was discarded, and the classes
were assimilated in the division organic chemistry.

At this time there existed a belief, held at a later date by Berzelius,
Gmelin and many others, that the formation of organic compounds was
conditioned by a so-called _vital force_; and the difficulty of
artificially realizing this action explained the supposed impossibility
of synthesizing organic compounds. This dogma was shaken by Wöhler's
synthesis of urea in 1828. But the belief died hard; the synthesis of
urea remained isolated for many years; and many explanations were
attempted by the vitalists (as, for instance, that urea was halfway
between the inorganic and organic kingdoms, or that the carbon, from
which it was obtained, retained the essentials of this hypothetical
vital force), but only to succumb at a later date to the indubitable
fact that the same laws of chemical combination prevail in both the
animate and inanimate kingdoms, and that the artificial or laboratory
synthesis of any substance, either inorganic or organic, is but a
question of time, once its constitution is determined.[10]

The exact delimitation of inorganic and organic chemistry engrossed many
minds for many years; and on this point there existed considerable
divergence of opinion for several decades. In addition to the vitalistic
doctrine of the origin of organic compounds, views based on purely
chemical considerations were advanced. The atomic theory, and its
correlatives--the laws of constant and multiple proportions--had been
shown to possess absolute validity so far as well-characterized
inorganic compounds were concerned; but it was open to question whether
organic compounds obeyed the same laws. Berzelius, in 1813 and 1814, by
improved methods of analysis, established that the Daltonian laws of
combination held in both the inorganic and organic kingdoms; and he
adopted the view of Lavoisier that organic compounds were oxides of
compound radicals, and therefore necessarily contained at least three
elements--carbon, hydrogen and oxygen. This view was accepted in 1817 by
Leopold Gmelin, who, in his _Handbuch der Chemie_, regarded inorganic
compounds as being of binary composition (the simplest being oxides both
acid and basic, which by combination form salts also of binary form),
and organic compounds as ternary, i.e. composed of three elements;
furthermore, he concluded that inorganic compounds could be synthesized,
whereas organic compounds could not. A consequence of this empirical
division was that marsh gas, ethylene and cyanogen were regarded as
inorganic, and at a later date many other hydrocarbons of undoubtedly
organic nature had to be included in the same division.

The binary conception of compounds held by Berzelius received apparent
support from the observations of Gay Lussac, in 1815, on the vapour
densities of alcohol and ether, which pointed to the conclusion that
these substances consisted of one molecule of water and one and two of
ethylene respectively; and from Pierre Jean Robiquet and Jean Jacques
Colin, showing, in 1816, that ethyl chloride (hydrochloric ether) could
be regarded as a compound of ethylene and hydrochloric acid.[11]
Compound radicals came to be regarded as the immediate constituents of
organic compounds; and, at first, a determination of their empirical
composition was supposed to be sufficient to characterize them. To this
problem there was added another in about the third decade of the 19th
century--namely, to determine the manner in which the atoms composing
the radical were combined; this supplementary requisite was due to the
discovery of the isomerism of silver fulminate and silver cyanate by
Justus von Liebig in 1823, and to M. Faraday's discovery of butylene,
isomeric with ethylene, in 1825.

The classical investigation of Liebig and Friedrich Wohler on the
radical of benzoic acid ("Über das Radikal der Benzoë-säure," _Ann.
Chem._, 1832, 3, p. 249) is to be regarded as a most important
contribution to the radical theory, for it was shown that a radical
containing the elements carbon, hydrogen and oxygen, which they named
benzoyl (the termination _yl_ coming from the Gr. [Greek: ylê], matter),
formed the basis of benzaldehyde, benzoic acid, benzoyl chloride,
benzoyl bromide and benzoyl sulphide, benzamide and benzoic ether.
Berzelius immediately appreciated the importance of this discovery,
notwithstanding that he was compelled to reject the theory that oxygen
could not play any part in a compound radical--a view which he
previously considered as axiomatic; and he suggested the names "proin"
or "orthrin" (from the Gr. [Greek: prôi] and [Greek: orthros], at dawn).
However, in 1833, Berzelius reverted to his earlier opinion that
oxygenated radicals were incompatible with his electrochemical theory;
he regarded benzoyl as an oxide of the radical C14H10, which he named
"picramyl" (from [Greek: pikros], bitter, and [Greek: amygdalê],
almond), the peroxide being anhydrous benzoic acid; and he dismissed the
views of Gay Lussac and Dumas that ethylene was the radical of ether,
alcohol and ethyl chloride, setting up in their place the idea that
ether was a suboxide of ethyl, (C2H5)2O, which was analogous to K2O,
while alcohol was an oxide of a radical C2H6; thus annihilating any
relation between these two compounds. This view was modified by Liebig,
who regarded ether as ethyl oxide, and alcohol as the hydrate of ethyl
oxide; here, however, he was in error, for he attributed to alcohol a
molecular weight double its true value. Notwithstanding these errors,
the value of the "ethyl theory" was perceived; other radicals--formyl,
methyl, amyl, acetyl, &c.--were characterized; Dumas, in 1837, admitted
the failure of the etherin theory; and, in company with Liebig, he
defined organic chemistry as the "chemistry of compound radicals." The
knowledge of compound radicals received further increment at the hands
of Robert W. Bunsen, the discoverer of the cacodyl compounds.

The radical theory, essentially dualistic in nature in view of its
similarity to the electrochemical theory of Berzelius, was destined to
succumb to a unitary theory. Instances had already been recorded of
cases where a halogen element replaced hydrogen with the production of a
closely allied substance: Gay Lussac had prepared cyanogen chloride from
hydrocyanic acid; Faraday, hexachlorethane from ethylene dichloride, &c.
Here the electro-negative halogens exercised a function similar to
electro-positive hydrogen. Dumas gave especial attention to such
substitutions, named _metalepsy_ [Greek: metalêpsis], exchange); and
framed the following empirical laws to explain the reactions:--(1) a
body containing hydrogen when substituted by a halogen loses one atom of
hydrogen for every atom of halogen introduced; (2) the same holds if
oxygen be present, except that when the oxygen is present as water the
latter first loses its hydrogen without replacement, and then
substitution according to (1) ensues. Dumas went no further that thus
epitomizing his observations; and the next development was made in 1836
by Auguste Laurent, who, having amplified and discussed the
applicability of Dumas' views, promulgated his _Nucleus Theory_, which
assumed the existence of "original nuclei or radicals" (_radicaux_ or
_noyaux fondamentaux_) composed of carbon and hydrogen, and "derived
nuclei" (_radicaux_ or _noyaux dérivés_) formed from the original nuclei
by the substitution of hydrogen or the addition of other elements, and
having properties closely related to the primary nuclei.

Vigorous opposition was made by Liebig and Berzelius, the latter
directing his attack against Dumas, whom he erroneously believed to be
the author of what was, in his opinion, a pernicious theory. Dumas
repudiated the accusation, affirming that he held exactly contrary views
to Laurent; but only to admit their correctness in 1839, when, from his
own researches and those of Laurent, Malaguti and Regnault, he
formulated his _type theory_. According to this theory a "chemical type"
embraced compounds containing the same number of equivalents combined in
a like manner and exhibiting similar properties; thus acetic and
trichloracetic acids, aldehyde and chloral, marsh gas and chloroform are
pairs of compounds referable to the same type. He also postulated, with
Regnault, the existence of "molecular or mechanical types" containing
substances which, although having the same number of equivalents, are
essentially different in characters. His unitary conceptions may be
summarized: every chemical compound forms a complete whole, and cannot
therefore consist of two parts; and its chemical character depends
primarily upon the arrangement and number of the atoms, and, in a lesser
degree, upon their chemical nature. More emphatic opposition to the
dualistic theory of Berzelius was hardly possible; this illustrious
chemist perceived that the validity of his electrochemical theory was
called in question, and therefore he waged vigorous war upon Dumas and
his followers. But he fought in a futile cause; to explain the facts put
forward by Dumas he had to invent intricate and involved hypotheses,
which, it must be said, did not meet with general acceptance; Liebig
seceded from him, and invited Wöhler to endeavour to correct him. Still,
till the last Berzelius remained faithful to his original theory;
experiment, which he had hitherto held to be the only sure method of
research, he discarded, and in its place he substituted pure
speculation, which greatly injured the radical theory. At the same time,
however, the conception of radicals could not be entirely displaced, for
the researches of Liebig and Wohler, and those made subsequently by
Bunsen, demonstrated beyond all doubt the advantages which would accrue
from their correct recognition.

A step forward--the fusion of Dumas', type theory and the radical
theory--was made by Laurent and Charles Gerhardt. As early as 1842,
Gerhardt in his _Précis de chimie organique_ exhibited a marked leaning
towards Dumas' theory, and it is without doubt that both Dumas and
Laurent exercised considerable influence on his views. Unwilling to
discard the strictly unitary views of these chemists, or to adopt the
copulae theory of Berzelius, he revived the notion of radicals in a new
form. According to Gerhardt, the process of substitution consisted of
the union of two _residues_ to form a unitary whole; these residues,
previously termed "compound radicals," are atomic complexes which remain
over from the interaction of two compounds. Thus, he interpreted the
interaction of benzene and nitric acid as C6H6 + HNO3 = C6H5NO2 + H2O,
the "residues" of benzene being C6H5 and H, and of nitric acid HO and
NO2. Similarly he represented the reactions investigated by Liebig and
Wöhler on benzoyl compounds as double decompositions.

This rejuvenation of the notion of radicals rapidly gained favour; and
the complete fusion of the radical theory with the theory of types was
not long delayed. In 1849 C.A. Wurtz discovered the amines or
substituted ammonias, previously predicted by Liebig; A.W. von Hofmann
continued the investigation, and established their recognition as
ammonia in which one or more hydrogen atoms had been replaced by
hydrocarbon radicals, thus formulating the "ammonia type." In 1850 A.W.
Williamson showed how alcohol and ether were to be regarded as derived
from water by substituting one or both hydrogen atoms by the ethyl
group; he derived acids and the acid anhydrides from the same type; and
from a comparison of many inorganic and the simple organic compounds he
concluded that this notion of a "water-type" clarified, in no small
measure, the conception of the structure of compounds.

These conclusions were co-ordinated in Gerhardt's "new theory of types."
Taking as types hydrogen, hydrochloric acid, water and ammonia, he
postulated that all organic compounds were referable to these four
forms: the hydrogen type included hydrocarbons, aldehydes and ketones;
the hydrochloric acid type, the chlorides, bromides and iodides; the
water type, the alcohols, ethers, monobasic acids, acid anhydrides, and
the analogous sulphur compounds; and the ammonia type, the amines,
acid-amides, and the analogous phosphorus and arsenic compounds. The
recognition of the polybasicity of acids, which followed from the
researches of Thomas Graham and Liebig, had caused Williamson to suggest
that dibasic acids could be referred to a double water type, the acid
radical replacing an atom of hydrogen in each water molecule; while his
discovery of tribasic formic ether, CH(OC2H5)3, in 1854 suggested a
triple water type. These views were extended by William Odling, and
adopted by Gerhardt, but with modifications of Williamson's aspects. A
further generalization was effected by August Kekulé, who rejected the
hydrochloric acid type as unnecessary, and introduced the methane type
and condensed mixed types. Pointing out that condensed types can only be
fused with a radical replacing more than one atom of hydrogen, he laid
the foundation of the doctrine of valency, a doctrine of incalculable
service to the knowledge of the structure of chemical compounds.

At about the same time Hermann Kolbe attempted a rehabilitation, with
certain modifications, of the dualistic conception of Berzelius. He
rejected the Berzelian tenet as to the unalterability of radicals, and
admitted that they exercised a considerable influence upon the compounds
with which they were copulated. By his own investigations and those of
Sir Edward Frankland it was proved that the radical methyl existed in
acetic acid; and by the electrolysis of sodium acetate, Kolbe concluded
that he had isolated this radical; in this, however, he was wrong, for
he really obtained ethane, C2H6, and not methyl, CH3. From similar
investigations of valerianic acid he was led to conclude that fatty
acids were oxygen compounds of the radicals hydrogen, methyl, ethyl,
&c., combined with the double carbon equivalent C2. Thus the radical of
acetic acid, acetyl,[12] was C2H3·C2. (It will be noticed that Kolbe
used the atomic weights H=1, C=6, O=8, S=16, &c.; his formulae, however,
were molecular formulae, i.e. the molecular weights were the same as in
use to-day.) This connecting link, C2, was regarded as essential, while
the methyl, ethyl, &c. was but a sort of appendage; but Kolbe could not
clearly conceive the manner of copulation.

The brilliant researches of Frankland on the organo-metallic compounds,
and his consequent doctrine of saturation capacity or valency of
elements and radicals, relieved Kolbe's views of all obscurity. The
doctrine of copulae was discarded, and in 1859 emphasis was given to the
view that all organic compounds were derivatives of inorganic by simple
substitution processes. He was thus enabled to predict compounds then
unknown, e.g. the secondary and tertiary alcohols; and with inestimable
perspicacity he proved intimate relations between compounds previously
held to be quite distinct. Lactic acid and alanine were shown to be oxy-
and amino-propionic acids respectively; glycollic acid and glycocoll,
oxy- and amino-acetic acids; salicylic and benzamic acids, oxy- and
amino-benzoic acids.

Another consequence of the doctrine of valency was that it permitted the
graphic representation of the molecule. The "structure theory" (or the
mode of linking of the atoms) of carbon compounds, founded by Butlerow,
Kekulé and Couper and, at a later date, marvellously enhanced by the
doctrine of stereo-isomerism, due to J.H. van't Hoff and Le Bel,
occupies such a position in organic chemistry that its value can never
be transcended. By its aid the molecule is represented as a collection
of atoms connected together by valencies in such a manner that the part
played by each atom is represented; isomerism, or the existence of two
or more chemically different substances having identical molecular
weights, is adequately shown; and, most important of all, once the
structure is determined, the synthesis of the compound is but a matter
of time.

In this summary the leading factors which have contributed to a correct
appreciation of organic compounds have so far been considered
historically, but instead of continuing this method it has been thought
advisable to present an epitome of present-day conclusions, not
chronologically, but as exhibiting the principles and subject-matter of
our science.

_Classification of Organic Compounds_.

An apt definition of organic chemistry is that it is "the study of the
hydrocarbons and their derivatives." This description, although not
absolutely comprehensive, serves as a convenient starting-point for a
preliminary classification, since a great number of substances,
including the most important, are directly referable to hydrocarbons,
being formed by replacing one or more hydrogen atoms by other atoms or
groups. Two distinct types of hydrocarbons exist: (1) those consisting
of an open chain of carbon atoms--named the "aliphatic series" ([Greek:
aleiphar], oil or fat), and (2) those consisting of a closed chain--the
"carbocyclic series." The second series can be further divided into two
groups: (1) those exhibiting properties closely analogous to the
aliphatic series--the polymethylenes (q.v.), and (2) a series exhibiting
properties differing in many respects from the aliphatic and
polymethylene compounds, and characterized by a peculiar stability which
is to be associated with the disposition of certain carbon valencies not
saturated by hydrogen--the "aromatic series." There also exists an
extensive class of compounds termed the "heterocyclic series"--these
compounds are derived from ring systems containing atoms other than
carbon; this class is more generally allied to the aromatic series than
to the aliphatic.

We now proceed to discuss the types of aliphatic compounds; then, the
characteristic groupings having been established, an epitome of their
derivatives will be given. Carbocyclic rings will next be treated,
benzene and its allies in some detail; and finally the heterocyclic
nuclei.

Accepting the doctrine of the tetravalency of carbon (its divalency in
such compounds as carbon monoxide, various isocyanides, fulminic acid,
&c., and its possible trivalency in M. Gomberg's triphenyl-methyl play
no part in what follows), it is readily seen that the simplest
hydrocarbon has the formula CH4 named methane, in which the hydrogen
atoms are of equal value, and which may be pictured as placed at the
vertices of a tetrahedron, the carbon atom occupying the centre. This
tetrahedral configuration is based on the existence of only one
methylene dichloride, two being necessary if the carbon valencies were
directed from the centre of a plane square to its corners, and on the
existence of two optical isomers of the formula C._A.B.D.E._, C being a
carbon atom and _A.B.D.E._ being different monovalent atoms or radicals
(see STEREO-ISOMERISM). The equivalence of the four hydrogen atoms of
methane rested on indirect evidence, e.g. the existence of only one
acetic acid, methyl chloride, and other monosubstitution
derivatives--until the experimental proof by L. Henry (_Zeit. f. Phys.
Chem._, 1888, 2, p. 553), who prepared the four nitromethanes, CH3NO2,
each atom in methane being successively replaced by the nitro-group.

  Henry started with methyl iodide, the formula of which we write in the
  form CI_{a}H_{b}H_{c}H_{d}. This readily gave with silver nitrite a
  nitromethane in which we may suppose the nitro-group to replace the a
  iodine atom, i.e. C(NO2)_{a}H_{b}H_{c}H_{d}. The same methyl iodide
  gave with potassium cyanide, acetonitril, which was hydrolysed to
  acetic acid; this must be C(COOH)_{a}H_{b}H_{c}H_{d}. Chlorination of
  this substance gave a monochloracetic acid; we will assume the
  chlorine atom to replace the b hydrogen atom. This acid with silver
  nitrite gave nitroacetic acid, which readily gave the second
  nitromethane, CH_{a}(NO2)_{b}H_{c}H_d identical with the first
  nitromethane. From the nitroacetic acid obtained above, malonic acid
  was prepared, and from this a monochlormalonic acid was obtained; we
  assume the chlorine atom to replace the c hydrogen atom. This acid
  gives with silver nitrite the corresponding nitromalonic acid, which
  readily yielded the third nitromethane, CH_{a}H_{b}(NO2)_{c}H_{d},
  also identical with the first. The fourth nitromethane was obtained
  from the nitromalonic acid previously mentioned by a repetition of the
  method by which the third was prepared; this was identical with the
  other three.

Let us now consider hydrocarbons containing 2 atoms of carbon. Three
such compounds are possible according to the number of valencies acting
directly between the carbon atoms. Thus, if they are connected by one
valency, and the remaining valencies saturated by hydrogen, we obtain
the compound H3C·CH3, ethane. This compound may be considered as derived
from methane, CH4, by replacing a hydrogen atom by the monovalent group
CH3, known as _methyl_; hence ethane may be named "methylmethane." If
the carbon atoms are connected by two valencies, we obtain a compound
H2C:CH2, ethylene; if by three valencies, HC÷CH, acetylene. These last
two compounds are termed _unsaturated_, whereas ethane is _saturated_.
It is obvious that we have derived three combinations of carbon with
hydrogen, characterized by containing a single, double, and triple
linkage; and from each of these, by the substitution of a methyl group
for a hydrogen atom, compounds of the same nature result. Thus ethane
gives H3C·CH2·CH3, propane; ethylene gives H2C:CH·CH3, propylene; and
acetylene gives HC÷C·CH3, allylene. By continuing the introduction of
methyl groups we obtain three series of homologous hydro-carbons given,
by the general formulae C_{n}H_{2n+2}, C_{n}H_{2n}, and C_{n}H_{2n-2},
each member differing from the preceding one of the same series by CH2.
It will be noticed that compounds containing two double linkages will
have the same general formula as the acetylene series; such compounds
are known as the "diolefines." Hydrocarbons containing any number of
double or triple linkages, as well as both double and triple linkages,
are possible, and a considerable number of such compounds have been
prepared.

  A more complete idea of the notion of a compound radical follows from
  a consideration of the compound propane. We derived this substance
  from ethane by introducing a methyl group; hence it may be termed
  "methylethane." Equally well we may derive it from methane by
  replacing a hydrogen atom by the monovalent group CH2·CH3, named
  ethyl; hence propane may be considered as "ethylmethane." Further,
  since methane may be regarded as formed by the conjunction of a methyl
  group with a hydrogen atom, it may be named "methyl hydride";
  similarly ethane is "ethyl hydride," propane, "propyl hydride," and so
  on. The importance of such groups as methyl, ethyl, &c. in attempting
  a nomenclature of organic compounds cannot be overestimated; these
  compound radicals, frequently termed _alkyl radicals_, serve a similar
  purpose to the organic chemist as the elements to the inorganic
  chemist.

In methane and ethane the hydrogen atoms are of equal value, and no
matter which one may be substituted by another element or group the same
compound will result. In propane, on the other hand, the hydrogen atoms
attached to the terminal carbon atoms differ from those joined to the
medial atom; we may therefore expect to obtain different compounds
according to the position of the hydrogen atom substituted. By
introducing a methyl group we may obtain CH3·CH2·CH2·CH3, known as
"normal" or n-_butane_, substitution occurring at a terminal atom, or
CH3·CH(CH3)·CH3, isobutane, substitution occurring at the medial atom.
From n-butane we may derive, by a similar substitution of methyl groups,
the two hydrocarbons: (1) CH3·CH2·CH2·CH2·CH3, and (2)
CH3·CH(CH3)·CH2·CH3; from isobutane we may also derive two compounds,
one identical with (2.), and a new one (3) CH3(CH3)C(CH3)CH3. These
three hydrocarbons are _isomeric_, i.e. they possess the same formula,
but differ in constitution. We notice that they may be differentiated as
follows: (1) is built up solely of methyl and ·CH2· (methylene) groups
and the molecule consists of a single chain; such hydrocarbons are
referred to as being _normal_; (2) has a branch and contains the group
÷CH (methine) in which the free valencies are attached to carbon atoms;
such hydrocarbons are termed _secondary_ or _iso_-; (3) is characterized
by a carbon atom linked directly to four other carbon atoms; such
hydrocarbons are known as _tertiary_.

Deferring the detailed discussion of cyclic or ringed hydrocarbons, a
correlation of the various types or classes of compounds which may be
derived from hydrocarbon nuclei will now be given. It will be seen that
each type depends upon a specific radical or atom, and the copulation of
this character with any hydrocarbon radical (open or cyclic) gives
origin to a compound of the same class.

It is convenient first to consider the effect of introducing one, two,
or three hydroxyl (OH) groups into the -CH3, >CH2, and ->CH groups,
which we have seen to characterize the different types of hydrocarbons.
It may be noticed here that cyclic nuclei can only contain the groups
>CH2 and ->CH, the first characterizing the polymethylene and reduced
heterocyclic compounds, the second true aromatic compounds.

  Substituting one hydroxyl group into each of these residues, we obtain
  radicals of the type -CH2·OH, >CH·OH, and ->C·OH; these compounds are
  known as _alcohols_ (q.v.), and are termed primary, secondary, and
  tertiary respectively. Polymethylenes can give only secondary and
  tertiary alcohols, benzene only tertiary; these latter compounds are
  known as _phenols_. A second hydroxyl group may be introduced into the
  residues -CH2·OH and >CH·OH, with the production of radicals of the
  form -CH(OH)2 and >C(OH)2. Compounds containing these groupings are,
  however, rarely observed (see CHLORAL), and it is generally found that
  when compounds of these types are expected, the elements of water are
  split off, and the typical groupings are reduced to -CH:O and >C:O.
  Compounds containing the group -CH:O are known as _aldehydes_ (q.v.),
  while the group >C:O (sometimes termed the carbonyl or keto group)
  characterizes the _ketones_ (q.v.). A third hydroxyl group may be
  introduced into the -CH:O residue with the formation of the radical
  -C(OH):O; this is known as the carboxyl group, and characterizes the
  _organic_ acids.

  Sulphur analogues of these oxygen compounds are known. Thus the
  thio-alcohols or _mercaptans_ (q.v.) contain the group -CH2·SH; and
  the elimination of the elements of sulphuretted hydrogen between two
  molecules of a thio-alcohol results in the formation of a thio-ether
  or sulphide, R2S. Oxidation of thio-ethers results in the formation of
  sulphoxides, R2:S:O, and sulphones, R2:SO2; oxidation of mercaptans
  yields sulphonic acids, R·SO3H, and of sodium mercaptides sulphinic
  acids, R·SO(OH). We may also notice that thio-ethers combine with
  alkyl iodides to form sulphine or sulphonium compounds, R3÷SI.
  Thio-aldehydes, thio-ketones and thio-acids also exist.

We proceed to consider various simple derivatives of the alcohols, which
we may here regard as hydroxy hydrocarbons, R·OH, where R is an alkyl
radical, either aliphatic or cyclic in nature.

  Of these, undoubtedly the simplest are the _ethers_ (q.v.), formed by
  the elimination of the elements of water between two molecules of the
  same alcohol, "simple ethers," or of different alcohols, "mixed
  ethers." These compounds may be regarded as oxides in just the same
  way as the alcohols are regarded as hydroxides. In fact, the analogy
  between the alkyl groups and metallic elements forms a convenient
  basis from which to consider many derivatives. Thus from ethyl alcohol
  there can be prepared compounds, termed _esters_ (q.v.), or ethereal
  salts, exactly comparable in structure with corresponding salts of,
  say, potassium; by the action of the phosphorus haloids, the hydroxyl
  group is replaced by a halogen atom with the formation of derivatives
  of the type R·Cl(Br,I); nitric acid forms nitrates, R·O·NO2; nitrous
  acid, nitrites, R·O·NO; sulphuric acid gives normal sulphates R2SO4,
  or acid sulphates, R·SO4H. Organic acids also condense with alcohols
  to form similar compounds: the fats, waxes, and essential oils are
  naturally occurring substances of this class.

  An important class of compounds, termed _amines_ (q.v.), results from
  the condensation of alcohols with ammonia, water being eliminated
  between the alcoholic hydroxyl group and a hydrogen atom of the
  ammonia. Three types of amines are possible and have been prepared:
  primary, R·NH2; secondary, R2:NH; and tertiary, R3÷N; the oxamines,
  R3N:O, are closely related to the tertiary ammonias, which also unite
  with a molecule of alkyl iodide to form salts of quaternary ammonium
  bases, e.g. R4N·I. It is worthy of note that phosphorus and arsenic
  bases analogous to the amines are known (see PHOSPHORUS and ARSENIC).
  From the primary amines are derived the diazo compounds (q.v.) and azo
  compounds (q.v.); closely related are the hydrazines (q.v.). Secondary
  amines yield nitrosamines, R2N·NO, with nitrous acid. By the action of
  hydroxylamine or phenylhydrazine on aldehydes or ketones, condensation
  occurs between the carbonyl oxygen of the aldehyde or ketone and the
  amino group of the hydroxylamine or hydrazine. Thus with hydroxylamine
  aldehydes yield aldoximes, R·CH:N·OH, and ketones, ketoximes, R2C:N·OH
  (see OXIMES), while phenyl hydrazine gives phenylhydrazones,
  R2C:N·NH·C6H5 (see HYDRAZONES). Oxyaldehydes and oxyketones (viz.
  compounds containing an oxy in addition to an aldehydic or ketonic
  group) undergo both condensation and oxidation when treated with
  phenylhydrazine, forming compounds known as osozones; these are of
  great importance in characterizing the sugars (q.v.).

The carboxyl group constitutes another convenient starting-point for the
orientation of many types of organic compounds. This group may be
considered as resulting from the fusion of a carbonyl (:CO) and a
hydroxyl (HO·) group; and we may expect to meet with compounds bearing
structural resemblances to the derivatives of alcohols and aldehydes (or
ketones).

  Considering derivatives primarily concerned with transformations of
  the hydroxyl group, we may regard our typical acid as a fusion of a
  radical R·CO- (named acetyl, propionyl, butyl, &c., generally
  according to the name of the hydrocarbon containing the same number of
  carbon atoms) and a hydroxyl group. By replacing the hydroxyl group by
  a halogen, acid-haloids result; by the elimination of the elements of
  water between two molecules, acid-anhydrides, which may be oxidized to
  acid-peroxides; by replacing the hydroxyl group by the group ·SH,
  thio-acids; by replacing it by the amino group, acid-amides (q.v.); by
  replacing it by the group -NH·NH2, acid-hydrazides. The structural
  relations of these compounds are here shown:

   R·CO·OH;      R·CO·Cl;        (R·CO)2O;       R·CO·SH;
     acid;    acid-chloride;   acid-anhydride;  thio-acid;

             R·CO·NH2;         R·CO·NH·NH2.
            acid-amide;      acid-hydrazide.

  It is necessary clearly to distinguish such compounds as the amino-
  (or amido-) acids and acid-amides; in the first case the amino group
  is substituted in the hydrocarbon residue, in the second it is
  substituted in the carboxyl group.

By transformations of the carbonyl group, and at the same time of the
hydroxyl group, many interesting types of nitrogen compounds may be
correlated.

  Thus from the acid-amides, which we have seen to be closely related to
  the acids themselves, we obtain, by replacing the carbonyl oxygen by
  chlorine, the acidamido-chlorides, R·CCl2·NH2, from which are derived
  the imido-chlorides, R·CCl:NH, by loss of one molecule of hydrochloric
  acid. By replacing the chlorine in the imido-chloride by an oxyalkyl
  group we obtain the imido-ethers, R·C(OR'):NH; and by an amino group,
  the amidines, R·C(NH2):NH. The carbonyl oxygen may also be replaced by
  the oxime group, :N·OH; thus the acids yield the hydroxamic acids,
  R·C(OH):NOH, and the acid-amides the amidoximes, R·C(NH2):NOH. Closely
  related to the amidoximes are the nitrolic acids, R·C(NO2):NOH.

_Cyclic Hydrocarbons and Nuclei._

Having passed in rapid review the various types of compounds derived by
substituting for hydrogen various atoms or groups of atoms in
hydrocarbons (the separate articles on specific compounds should be
consulted for more detailed accounts), we now proceed to consider the
closed chain compounds. Here we meet with a great diversity of types:
oxygen, nitrogen, sulphur and other elements may, in addition to carbon,
combine together in a great number of arrangements to form cyclic
nuclei, which exhibit characters closely resembling open-chain compounds
in so far as they yield substitution derivatives, and behave as compound
radicals. In classifying closed chain compounds, the first step consists
in dividing them into: (1) _carbocyclic_, in which the ring is composed
solely of carbon atoms--these are also known as _homocyclic_ or
_isocyclic_ on account of the identity of the members of the ring--and
(2) _heterocyclic_, in which different elements go to make up the ring.
Two primary divisions of carbocyclic compounds may be conveniently made:
(1) those in which the carbon atoms are completely saturated--these are
known by the generic term _polymethylenes_, their general formula being
(CH2)_n: it will be noticed that they are isomeric with ethylene
and its homologues; they differ, however, from this series in not
containing a double linkage, but have a ringed structure; and (2) those
containing fewer hydrogen atoms than suffice to saturate the carbon
valencies--these are known as the _aromatic compounds_ proper, or as
_benzene compounds_, from the predominant part which benzene plays in
their constitution.

It was long supposed that the simplest ring obtainable contained six
atoms of carbon, and the discovery of trimethylene in 1882 by August
Freund by the action of sodium on trimethylene bromide, Br(CH2)3Br, came
somewhat as a surprise, especially in view of its behaviour with bromine
and hydrogen bromide. In comparison with the isomeric propylene,
CH3·HC:CH2, it is remarkably inert, being only very slowly attacked by
bromine, which readily combines with propylene. But on the other hand,
it is readily converted by hydrobromic acid into normal propyl bromide,
CH3·CH2·CH2Br. The separation of carbon atoms united by single
affinities in this manner at the time the observation was made was
altogether without precedent. A similar behaviour has since been noticed
in other trimethylene derivatives, but the fact that bromine, which
usually acts so much more readily than hydrobromic acid on unsaturated
compounds, should be so inert when hydrobromic acid acts readily is one
still needing a satisfactory explanation. A great impetus was given to
the study of polymethylene derivatives by the important and unexpected
observation made by W.H. Perkin, junr., in 1883, that ethylene and
trimethylene bromides are capable of acting in such a way on sodium
acetoacetic ester as to form tri- and tetra-methylene rings. Perkin has
himself contributed largely to our knowledge of such compounds; penta-
and hexa-methylene derivatives have also received considerable attention
(see POLYMETHYLENES).

A. von Baeyer has sought to explain the variations in stability manifest
in the various polymethylene rings by a purely mechanical hypothesis,
the "strain" or _Spannungs_ theory (_Ber._, 1885, p. 2277). Assuming the
four valencies of the carbon atom to be directed from the centre of a
regular tetrahedron towards its four corners, the angle at which they
meet is 109° 28'. Baeyer supposes that in the formation of carbon
"rings" the valencies become deflected from their positions, and that
the tension thus introduced may be deduced from a comparison of this
angle with the angles at which the strained valencies would meet. He
regards the amount of deflection as a measure of the stability of the
"ring." The readiness with which ethylene is acted on in comparison with
other types of hydrocarbon, for example, is in harmony, he considers,
with the circumstance that the greatest distortion must be involved in
its formation, as if deflected into parallelism each valency will be
drawn out of its position through ½.109° 28'. The values in other cases
are calculable from the formula ½(1O9° 28' - a), where a is the internal
angle of the regular polygon contained by sides equal in number to the
number of the carbon atoms composing the ring. These values are:--

         Trimethylene.                    Tetramethylene.
  ½(109° 28' - 60°) = 24° 44'.      ½(109° 28' - 90°) = 9° 44'.

         Pentamethylene.                  Hexamethylene.
  ½(109° 28' - 108°) = 0° 44'.      ½(109° 28' - 120°) = -5° 16'.

The general behaviour of the several types of hydrocarbons is certainly
in accordance with this conception, and it is a remarkable fact that
when benzene is reduced with hydriodic acid, it is converted into a
mixture of hexamethylene and methylpentamethylene (cf. W. Markownikov,
_Ann._, 1898, 302, p. 1); and many other cases of the conversion of
six-carbon rings into five-carbon rings have been recorded (see below,
_Decompositions of the Benzene Ring_). Similar considerations will apply
to rings containing other elements besides carbon. As an illustration it
may be pointed out that in the case of the two known types of
lactones--the [gamma]-lactones, which contain four carbon atoms and one
oxygen atom in the ring, are more readily formed and more stable (less
readily hydrolysed) than the [delta]-lactones, which contain one oxygen
and five carbon atoms in the ring. That the number of atoms which can be
associated in a ring by single affinities is limited there can be no
doubt, but there is not yet sufficient evidence to show where the limit
must be placed. Baeyer has suggested that his hypothesis may also be
applied to explain the instability of acetylene and its derivatives, and
the still greater instability of the polyacetylene compounds.

_Benzene._

The ringed structure of benzene, C6H6, was first suggested in 1865
by August Kekulé, who represented the molecule by six CH groups placed
at the six angles of a regular hexagon, the sides of which denoted the
valencies saturated by adjacent carbon atoms, the fourth valencies of
each carbon atom being represented as saturated along alternate sides.
This formula, notwithstanding many attempts at both disproving and
modifying it, has well stood the test of time; the subject has been the
basis of constant discussion, many variations have been proposed, but
the original conception of Kekulé remains quite as convenient as any of
the newer forms, especially when considering the syntheses and
decompositions of the benzene complex. It will be seen, however, that
the absolute disposition of the fourth valency may be ignored in a great
many cases, and consequently the complex may be adequately represented
as a hexagon. This symbol is in general use; it is assumed that at each
corner there is a CH group which, however, is not always written in; if
a hydrogen atom be substituted by another group, then this group is
attached to the corner previously occupied by the displaced hydrogen.
The following diagrams illustrate these statements:--

          CH             ^              C·OH           OH
        /    \\        /   \           /    \\        /   \
  HC  /       \\ CH  /       \   HC  /       \\ CH  /       \
     ||         |   |         |     ||        |    |         |
     ||         |   |         |     ||        |    |         |
  HC  \       // CH  \       /   HC  \       // CH  \       /
        \    //        \   /           \    //        \   /
          CH             v               CH             v

       Benzene.     Abbreviated.     Oxybenzene.   Abbreviated.

  From the benzene nucleus we can derive other aromatic nuclei,
  graphically represented by fusing two or more hexagons along common
  sides. By fusing two nuclei we obtain the formula of naphthalene,
  C10H10; by fusing three, the hydrocarbons anthracene and phenanthrene,
  C14H10; by fusing four, chrysene, C18H12, and possibly pyrene, C16H10;
  by fusing five, picene, C22H14. But it must be here understood that
  each member of these _condensed nuclei_ need not necessarily be
  identical in structure; thus the central nuclei in anthracene and
  phenanthrene differ very considerably from the terminal nuclei (see
  below, _Condensed Nuclei_). Other hydrocarbon nuclei generally
  classed as aromatic in character result from the union of two or more
  benzene nuclei joined by one or two valencies with polymethylene or
  oxidized polymethylene rings; instances of such nuclei are indene,
  hydrindene, fluorene, and fluor-anthene. From these nuclei an immense
  number of derivatives may be obtained, for the hydrogen atoms may be
  substituted by any of the radicals discussed in the preceding section
  on the classification of organic compounds.


  Distinctions between aliphatic and aromatic compounds.

We now proceed to consider the properties, syntheses, decompositions and
constitution of the benzene complex. It has already been stated that
benzene derivatives may be regarded as formed by the replacement of
hydrogen atoms by other elements or radicals in exactly the same manner
as in the aliphatic series. Important differences, however, are
immediately met with when we consider the methods by which derivatives
are obtained. For example: nitric acid and sulphuric acid readily react
with benzene and its homologues with the production of nitro derivatives
and sulphonic acids, while in the aliphatic series these acids exert no
substituting action (in the case of the olefines, the latter acid forms
an addition product); another distinction is that the benzene complex is
more stable towards oxidizing agents. This and other facts connected
with the stability of benzenoid compounds are clearly shown when we
consider mixed aliphatic-aromatic hydrocarbons, i.e. compounds derived
by substituting aliphatic radicals in the benzene nucleus; such a
compound is methylbenzene or toluene, C6H5·CH3. This compound is readily
oxidized to benzoic acid, C6H5·COOH, the aromatic residue being
unattacked; nitric and sulphuric acids produce nitro-toluenes,
C6H4·CH3·NO2, and toluene sulphonic acids, C6H4·CH3·SO3H; chlorination
may result in the formation of derivatives substituted either in the
aromatic nucleus or in the side chain; the former substitution occurs
most readily, chlor-toluenes, C6H4·CH3·Cl, being formed, while the
latter, which needs an elevation in temperature or other auxiliary,
yields benzyl chloride, C6H5·CH2Cl, and benzal chloride, C6H5·CHCl2. In
general, the aliphatic residues in such mixed compounds retain the
characters of their class, while the aromatic residues retain the
properties of benzene.

Further differences become apparent when various typical compounds are
compared. The introduction of hydroxyl groups into the benzene nucleus
gives rise to compounds generically named _phenols_, which, although
resembling the aliphatic alcohols in their origin, differ from these
substances in their increased chemical activity and acid nature. The
phenols more closely resemble the tertiary alcohols, since the hydroxyl
group is linked to a carbon atom which is united to other carbon atoms
by its remaining three valencies; hence on oxidation they cannot yield
the corresponding aldehydes, ketones or acids (see below,
_Decompositions of the Benzene Ring_). The amines also exhibit striking
differences: in the aliphatic series these compounds may be directly
formed from the alkyl haloids and ammonia, but in the benzene series
this reaction is quite impossible unless the haloid atom be weakened by
the presence of other substituents, e.g. nitro groups. Moreover, while
methylamine, dimethylamine, and trimethylamine increase in basicity
corresponding to the introduction of successive methyl groups,
phenylamine or aniline, diphenylamine, and triphenylamine are in
decreasing order of basicity, the salts of diphenylamine being
decomposed by water. Mixed aromatic-aliphatic amines, both secondary and
tertiary, are also more strongly basic than the pure aromatic amines,
and less basic than the true aliphatic compounds; e.g. aniline,
C6H5·NH2, monomethyl aniline, C6H5·NH·CH3, and dimethyl aniline,
C6H5·N(CH3)2, are in increasing order of basicity. These observations
may be summarized by saying that the benzene nucleus is more negative in
character than the aliphatic residues.

_Isomerism of Benzene Derivatives._--Although Kekulé founded his famous
benzene formula in 1865 on the assumptions that the six hydrogen atoms
in benzene are equivalent and that the molecule is symmetrical, i.e.
that two pairs of hydrogen atoms are symmetrically situated with
reference to any specified hydrogen atom, the absolute demonstration of
the validity of these assumptions was first given by A. Ladenburg in
1874 (see _Ber._, 1874, 7, p. 1684; 1875, 8, p. 1666; _Theorie der
aromatischen Verbindungen_, 1876). These results may be graphically
represented as follows: numbering the hydrogen atoms in cyclical order
from 1 to 6, then the first thesis demands that whichever atom is
substituted the same compound results, while the second thesis points
out that the pairs 2 and 6, and 3 and 5 are symmetrical with respect to
1, or in other words, the di-substitution derivatives 1.2 and 1.6, and
also 1.3 and 1.5 are identical. Therefore three di-derivatives are
possible, viz. 1.2 or 1.6, named _ortho_- (o), 1.3 or 1.5, named _meta_-
(m), and 1.4, named _para_- compounds (p). In the same way it may be
shown that three tri-substitution, three tetra-substitution, one
penta-substitution, and one hexa-substitution derivative are possible.
Of the tri-substitution derivatives, 1.2.3.-compounds are known as
"adjacent" or "vicinal" (v), the 1.2.4 as "asymmetrical" (as), the 1.3.5
as "symmetrical" (s); of the tetra-substitution derivatives,
1.2.3.4-compounds are known as "adjacent," 1.2.3.5 as "asymmetrical,"
and 1.2.4.5 as "symmetrical."

       Di-derivatives            Tri-derivatives          Tetra-derivatives
   _____________________      _____________________      _____________________
  /                     \    /                     \    /                     \
    X        X        X        X        X        X        X        X        X
    /\       /\       /\       /\       /\       /\       /\       /\       /\
   /  \X    /  \     /  \     /  \X    /  \X    /  \     /  \X    /  \X    /  \X
  |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |
  |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |   |    |
   \  /     \  /X    \  /     \  /X    \  /    X\  /X    \  /X   X\  /X   X\  /
    \/       \/       \/       \/       \/       \/       \/       \/       \/
                      X                 X                 X                 X
    o        m        p        v        as       s        v        as       s

Here we have assumed the substituent groups to be alike; when they are
unlike, a greater number of isomers is possible. Thus in the
tri-substitution derivatives six isomers, and no more, are possible when
two of the substituents are alike; for instance, six diaminobenzoic
acids, C6H3(NH2)2COOH, are known; when all are unlike ten isomers are
possible; thus, ten oxytoluic acids, C6H3·CH3·OH·COOH, are known. In the
case of tetra-substituted compounds, thirty isomers are possible when
all the groups are different.


  Equivalence of four hydrogen atoms.

  The preceding considerations render it comparatively easy to follow
  the reasoning on which the experimental verification of the above
  statements is based. The proof is divided into two parts: (1) that
  four hydrogen atoms are equal, and (2) that two pairs of hydrogen
  atoms are symmetrical with reference to a specified hydrogen atom. In
  the first thesis, phenol or oxybenzene, C6H5·OH, in which we will
  assume the hydroxyl group to occupy position 1, is converted into
  brombenzene, which is then converted into benzoic acid, C6H5·COOH.
  From this substance, an oxybenzoic acid (_meta_-), C6H4·OH·COOH, may
  be prepared; and the two other known oxybenzoic acids (_ortho_- and
  _para_-) may be converted into benzoic acid. These three acids yield
  on heating phenol, identical with the substance started with, and
  since in the three oxybenzoic acids the hydroxyl groups must occupy
  positions other than 1, it follows that _four_ hydrogen atoms are
  equal in value.


  Symmetry of pairs of hydrogen atoms.

  R. Hübner and A. Petermann (_Ann._, 1869, 149, p. 129) provided the
  proof of the equivalence of the atoms 2 and 6 with respect to 1. From
  meta-brombenzoic acid two nitrobrombenzoic acids are obtained on
  direct nitration; elimination of the bromine atom and the reduction of
  the nitro to an amino group in these two acids results in the
  formation of the same ortho-aminobenzoic acid. Hence the positions
  occupied by the nitro groups in the two different nitrobrombenzoic
  acids must be symmetrical with respect to the carboxyl group. In 1879,
  Hübner (_Ann._, 195, p. 4) proved the equivalence of the second pair,
  viz. 3 and 5, by starting out with ortho-aminobenzoic acid, previously
  obtained by two different methods. This substance readily yields
  ortho-oxybenzoic acid or salicylic acid, which on nitration yields two
  mononitro-oxybenzoic acids. By eliminating the hydroxy groups in these
  acids the same nitrobenzoic acid is obtained, which yields on
  reduction an aminobenzoic acid different from the starting-out acid.
  Therefore there must be another pair of hydrogen atoms, other than 2
  and 6, which are symmetrical with respect to 1. The symmetry of the
  second pair was also established in 1878 by E. Wroblewsky (_Ann._,
  192, p. 196).

_Orientation of Substituent Groups._--The determination of the relative
positions of the substituents in a benzene derivative constitutes an
important factor in the general investigation of such compounds.
Confining our attention, for the present, to di-substitution products we
see that there are three distinct series of compounds to be considered.
Generally if any group be replaced by another group, then the second
group enters the nucleus in the position occupied by the displaced
group; this means that if we can definitely orientate three
di-derivatives of benzene, then any other compound, which can be
obtained from or converted into one of our typical derivatives, may be
definitely orientated. Intermolecular transformations--migrations of
substituent groups from one carbon atom to another--are of fairly common
occurrence among oxy compounds at elevated temperatures. Thus potassium
ortho-oxybenzoate is converted into the salt of para-oxybenzoic acid at
220°; the three bromphenols, and also the brombenzenesulphonic acids,
yield m-dioxybenzene or resorcin when fused with potash. It is
necessary, therefore, to avoid reactions involving such intermolecular
migrations when determining the orientation of aromatic compounds.

  Such a series of typical compounds are the benzene dicarboxylic acids
  (phthalic acids), C6H4(COOH)2. C. Graebe (_Ann._, 1869, 149, p. 22)
  orientated the ortho-compound or phthalic acid from its formation from
  naphthalene on oxidation; the meta-compound or isophthalic acid is
  orientated by its production from mesitylene, shown by A. Ladenburg
  (_Ann._, 1875, 179, p. 163) to be symmetrical trimethyl benzene;
  terephthalic acid, the remaining isomer, must therefore be the
  para-compound.

  P. Griess (_Ber._, 1872, 5, p. 192; 1874, 7, p. 1223) orientated the
  three diaminobenzenes or phenylene diamines by considering their
  preparation by the elimination of the carboxyl group in the six
  diaminobenzoic acids. The diaminobenzene resulting from two of these
  acids is the ortho-compound; from three, the meta-; and from one the
  para-; this is explained by the following scheme:--

    NH2         NH2        NH2         NH2           NH2       NH2
     ^           ^          ^           ^             ^         ^
   /   \NH2    /   \NH2   /   \COOH   /   \         /   \     /   \COOH
  |     |     |     |    |     |     |     |       |     |   |     |
  |     |     |     |    |     |     |     |       |     |   |     |
   \   /COOH   \   /      \   /NH2    \   /NH2 HOOC \   /NH2  \   /
     v           v          v           v             v         v
                   COOH                COOH                    NH2
  \________ _______/  ,   \______________ ______________/  ,
           v                             v
          NH2                           NH2                    NH2
           ^                             ^                      ^
         /   \NH2                      /   \NH2               /   \
        |     |                       |     |                |     |
        |     |                       |     |                |     |
         \   /                         \   /NH2               \   /
           v                             v                      v
                                        COOH                   NH2

  W. Körner (_Gazz. Chem. Ital._, 4, p. 305) in 1874 orientated the
  three dibrombenzenes in a somewhat similar manner. Starting with the
  three isomeric compounds, he found that one gave two tribrombenzenes,
  another gave three, while the third gave only one. A scheme such as
  the preceding one shows that the first dibrombenzene must be the
  ortho-compound, the second the meta-, and the third the
  para-derivative. Further research in this direction was made by D.E.
  Noetling (_Ber._, 1885, 18, p. 2657), who investigated the nitro-,
  amino-, and oxy-xylenes in their relations to the three xylenes or
  dimethyl benzenes.

  The orientation of higher substitution derivatives is determined by
  considering the di- and tri-substitution compounds into which they can
  be transformed.

_Substitution of the Benzene Ring._--As a general rule, homologues and
mono-derivatives of benzene react more readily with substituting agents
than the parent hydrocarbon; for example, phenol is converted into
tribromphenol by the action of bromine water, and into the nitrophenols
by dilute nitric acid; similar activity characterizes aniline. Not only
does the substituent group modify the readiness with which the
derivative is attacked, but also the nature of the product. Starting
with a mono-derivative, we have seen that a substituent group may enter
in either of three positions to form an ortho-, meta-, or para-compound.
Experience has shown that such mono-derivatives as nitro compounds,
sulphonic acids, carboxylic acids, aldehydes, and ketones yield as a
general rule chiefly the meta-compounds, and this is independent of the
nature of the second group introduced; on the other hand, benzene
haloids, amino-, homologous-, and hydroxy-benzenes yield principally a
mixture of the ortho- and para-compounds. These facts are embodied in
the "Rule of Crum Brown and J. Gibson" (_Jour. Chem. Soc._ 61, p. 367):
If the hydrogen compound of the substituent already in the benzene
nucleus can be directly oxidized to the corresponding hydroxyl compound,
then meta-derivatives predominate on further substitution, if not, then
ortho- and para-derivatives. By further substitution of ortho- and
para-di-derivatives, in general the same tri-derivative [1.2.4] is
formed (_Ann._, 1878, 192, p. 219); meta-compounds yield [1.3.4] and
[1.2.3] tri-derivatives, except in such cases as when both substituent
groups are strongly acid, e.g. m-dinitrobenzene, then [1.3.5]-derivatives
are obtained.

_Syntheses of the Benzene Ring._--The characteristic distinctions which
exist between aliphatic and benzenoid compounds make the transformations
of one class into the other especially interesting.

  In the first place we may notice a tendency of several aliphatic
  compounds, e.g. methane, tetrachlormethane, &c., to yield aromatic
  compounds when subjected to a high temperature, the so-called
  pyrogenetic reactions (from Greek [Greek: pyr], fire, and [Greek:
  gennaô], I produce); the predominance of benzenoid, and related
  compounds--naphthalene, anthracene, phenanthrene, &c.--in coal-tar is
  probably to be associated with similar pyrocondensations.
  Long-continued treatment with halogens may, in some cases, result in
  the formation of aromatic compounds; thus perchlorbenzene, C6Cl6,
  frequently appears as a product of exhaustive chlorination, while
  hexyl iodide, C6H13I, yields perchlor- and perbrom-benzene quite
  readily.

  The trimolecular polymerization of numerous acetylene
  compounds--substances containing two trebly linked carbon atoms,
  --C:C--, to form derivatives of benzene is of considerable interest.
  M.P.E. Berthelot first accomplished the synthesis of benzene in 1870
  by leading acetylene, HC÷CH, through tubes heated to dull redness; at
  higher temperatures the action becomes reversible, the benzene
  yielding diphenyl, diphenylbenzene, and acetylene. The condensation of
  acetylene to benzene is also possible at ordinary temperatures by
  leading the gas over pyrophoric iron, nickel, cobalt, or spongy
  platinum (P. Sabatier and J.B. Senderens). The homologues of acetylene
  condense more readily; thus allylene, CH÷C·CH3, and crotonylene,
  CH3·C÷C·CH3, yield trimethyl- and hexamethyl-benzene under the
  influence of sulphuric acid. Toluene or mono-methylbenzene results
  from the pyrocondensation of a mixture of acetylene and allylene.
  Substituted acetylenes also exhibit this form of condensation; for
  instance, bromacetylene, BrC÷CH, is readily converted into
  tribrombenzene, while propiolic acid, HC÷C·COOH, under the influence
  of sunlight, gives benzene tricarboxylic acid.

  A larger and more important series of condensations may be grouped
  together as resulting from the elimination of the elements of water
  between carbonyl (CO) and methylene (CH2) groups. A historic example is
  that of the condensation of three molecules of acetone, CH3·CO·CH3, in
  the presence of sulphuric acid, to s-trimethylbenzene or mesitylene,
  C6H3(CH3)3, first observed in 1837 by R. Kane; methylethyl ketone and
  methyl-n-propyl ketone suffer similar condensations to s-triethylbenzene
  and s-tri-n-propylbenzene respectively. Somewhat similar condensations
  are: of geranial or citral, (CH3)2CH·CH2·CH:CH·C(CH3):CH·CHO, to
  p-isopropyl-methylbenzene or cymene; of the condensation product of
  methylethylacrolein and acetone, CH3·CH2·CH:C(CH3)·CH:CH·CO·CH3, to
  [1.3.4]-trimethylbenzene or pseudocumene; and of the condensation
  product of two molecules of isovaleryl aldehyde with one of acetone,
  C3H7·CH2·CH:C(C3H7)·CH:CH·CO·CH3, to (1)-methyl-2-4-di-isopropyl
  benzene. An analogous synthesis is that of di-hydro-m-xylene from methyl
  heptenone, (CH3)2C:CH·(CH2)2·CO·CH3. Certain a-diketones condense to
  form benzenoid quinones, two molecules of the diketone taking part in
  the reaction; thus diacetyl, CH3·CO·CO·CH3, yields p-xyloquinone,
  C6H2(CH3)2O2 (_Ber._, 1888, 21, p. 1411), and acetylpropionyl,
  CH3·CO·CO·C2H5, yields duroquinone, or tetramethylquinone, C6(CH3)4O2.
  Oxymethylene compounds, characterized by the grouping >C:CH(OH), also
  give benzene derivatives by hydrolytic condensation between three
  molecules; thus oxymethylene acetone, or formyl acetone,
  CH3·CO·CH:CH(OH), formed by acting on formic ester with acetone in the
  presence of sodium ethylate, readily yields [1.3.5]-triacetylbenzene,
  C6H3(CO·CH3)3; oxymethylene acetic ester or formyl acetic ester or
  [beta]-oxyacrylic ester, (HO)CH:CH·CO2C2H5, formed by condensing acetic
  ester with formic ester, and also its dimolecular condensation product,
  coumalic acid, readily yields esters of [1.3.5]-benzene tricarboxylic
  acid or trimesic acid (see _Ber._, 1887, 20, p. 2930).

  In 1890, O. Doebner (_Ber._ 23, p. 2377) investigated the condensation
  of pyroracemic acid, CH3·CO·COOH, with various aliphatic aldehydes,
  and obtained from two molecules of the acid and one of the aldehyde in
  the presence of baryta water alkylic isophthalic acids: with
  acetaldehyde [1.3.5]-methylisophthalic acid or uvitic acid,
  C6H3·CH3·(COOH)2, was obtained, with propionic aldehyde
  [1.3.5]-ethylisophthalic acid, and with butyric aldehyde the
  corresponding propylisophthalic acid. We may here mention the
  synthesis of oxyuvitic ester (5-methyl-4-oxy-1-3-benzene dicarboxylic
  ester) by the condensation of two molecules of sodium acetoacetic
  ester with one of chloroform (_Ann._, 1883, 222, p. 249). Of other
  syntheses of true benzene derivatives, mention may be made of the
  formation of orcinol or [3.5]-dioxytoluene from dehydracetic acid; and
  the formation of esters of oxytoluic acid (5-methyl-3-oxy-benzoic
  acid), C6H3·CH3·OH·COOH, when acetoneoxalic ester,
  CH3·CO·CH2·CO·CO·CO2C2H5, is boiled with baryta (_Ber._, 1889, 22, p.
  3271). Of interest also are H.B. Hill and J. Torray's observations on
  nitromalonic aldehyde, NO2·CH(CHO)2, formed by acting on mucobromic
  acid, probably CHO·CBr:CBr:COOH, with alkaline nitrites; this
  substance condenses with acetone to give p-nitrophenol, and forms
  [1.3.5]-trinitrobenzene when its sodium salt is decomposed with an
  acid.

  By passing carbon monoxide over heated potassium J. von Liebig
  discovered, in 1834, an interesting aromatic compound, potassium
  carbon monoxide or potassium hexaoxybenzene, the nature of which was
  satisfactorily cleared up by R. Nietzki and T. Benckiser (_Ber_. 18,
  p. 499) in 1885, who showed that it yielded hexaoxybenzene, C6(OH)6,
  when acted upon with dilute hydrochloric acid; further investigation
  of this compound brought to light a considerable number of highly
  interesting derivatives (see QUINONES). Another hexa-substituted
  benzene compound capable of direct synthesis is mellitic acid or
  benzene carboxylic acid, C6(COOH)6. This substance, first obtained
  from the mineral honeystone, aluminium mellitate, by M.H. Klaproth in
  1799, is obtained when pure carbon (graphite or charcoal) is oxidized
  by alkaline permanganate, or when carbon forms the positive pole in an
  electrolytic cell (_Ber._, 1883, 16, p. 1209). The composition of this
  substance was determined by A. von Baeyer in 1870, who obtained
  benzene on distilling the calcium salt with lime.

  Hitherto we have generally restricted ourselves to syntheses which
  result in the production of a true benzene ring; but there are many
  reactions by which reduced benzene rings are synthesized, and from the
  compounds so obtained true benzenoid compounds may be prepared. Of such
  syntheses we may notice: the condensation of sodium malonic ester to
  phloroglucin tricarboxylic ester, a substance which gives phloroglucin
  or trioxybenzene when fused with alkalis, and behaves both as a
  triketohexamethylene tricarboxylic ester and as a trioxybenzene
  tricarboxylic ester; the condensation of succinic ester, (CH2·CO2C2H5)2,
  under the influence of sodium to succinosuccinic ester, a
  diketohexamethylene dicarboxylic ester, which readily yields
  dioxyterephthalic acid and hydroquinpne (F. Herrmann, _Ann._, 1882, 211,
  p. 306; also see below, _Configuration of the Benzene Complex_); the
  condensation of acetone dicarboxylic ester with malonic ester to form
  triketohexamethylene dicarboxylic ester (E. Rimini, _Gazz. Chem._, 1896,
  26, (2), p. 374); the condensation of acetone-di-propionic acid under
  the influence of boiling water to a diketohexamethylene propionic acid
  (von Pechmann and Sidgwick, _Ber._, 1904, 37, p. 3816). Many diketo
  compounds suffer condensation between two molecules to form hydrobenzene
  derivatives, thus [alpha,gamma]-di-acetoglutaric ester,
  C2H5O2C(CH3·CO)CH·CH2·CH(CO·CH3)CO2C2H5, yields a
  methyl-ketohexamethylene, while [gamma]-acetobutyric ester,
  CH3CO(CH2)2CO2C2H5, is converted into dihydroresorcinol or
  m-diketohexamethylene by sodium ethylate; this last reaction is reversed
  by baryta (see _Decompositions of Benzene Ring_). For other syntheses of
  hexamethylene derivatives, see POLYMETHYLENES.

_Decompositions of the Benzene Ring._--We have previously alluded to the
relative stability of the benzene complex; consequently reactions which
lead to its disruption are all the more interesting, and have engaged
the attention of many chemists. If we accept Kekulé's formula for the
benzene nucleus, then we may expect the double linkages to be opened up
partially, either by oxidation or reduction, with the formation of di-,
tetra-, or hexa-hydro derivatives, or entirely, with the production of
open chain compounds. Generally rupture occurs at more than one point;
and rarely are the six carbon atoms of the complex regained as an open
chain. Certain compounds withstand ring decomposition much more strongly
than others; for instance, benzene and its homologues, carboxylic acids,
and nitro compounds are much more stable towards oxidizing agents than
amino- and oxy-benzenes, aminophenols, quinones, and oxy-carboxylic
acids.


  Simple oxidation.

  Strong oxidation breaks the benzene complex into such compounds as
  carbon dioxide, oxalic acid, formic acid, &c.; such decompositions are
  of little interest. More important are Kekulé's observations that
  nitrous acid oxidizes pyrocatechol or [1.2]-dioxybenzene, and
  protocatechuic acid or [3.4]-dioxybenzoic acid to dioxytartaric acid,
  (C(OH)2·COOH)2 (_Ann._, 1883, 221, p. 230); and O. Doebner's
  preparation of mesotartaric acid, the internally compensated tartaric
  acid, (CH(OH)·COOH)2, by oxidizing phenol with dilute potassium
  permanganate (_Ber._, 1891, 24, p. 1753).


  Chlorination and oxidation.

  For many years it had been known that a mixture of potassium chlorate
  and hydrochloric or sulphuric acids possessed strong oxidizing powers.
  L. Carius showed that potassium chlorate and sulphuric acid oxidized
  benzene to trichlor-phenomalic acid, a substance afterwards
  investigated by Kekulé and O. Strecker (_Ann._, 1884, 223, p. 170),
  and shown to be [beta]-trichloracetoacrylic acid, CCl3·CO·CH:CH·COOH,
  which with baryta gave chloroform and maleic acid. Potassium chlorate
  and hydrochloric acid oxidize phenol, salicylic acid (o-oxybenzoic
  acid), and gallic acid ([2.3.4] trioxybenzoic acid) to
  trichlorpyroracemic acid (isotrichlorglyceric acid), CCl3·C(OH)2·CO2H,
  a substance also obtained from trichloracetonitrile, CCl3·CO·CN, by
  hydrolysis. We may also notice the conversion of picric acid,
  ([2.4.6]-trinitrophenol) into chloropicrin, CCl3NO2, by bleaching lime
  (calcium hypochlorite), and into bromopicrin, CBr3NO2, by bromine
  water.

  The action of chlorine upon di-and tri-oxybenzenes has been carefully
  investigated by Th. Zincke; and his researches have led to the
  discovery of many chlorinated oxidation products which admit of
  decomposition into cyclic compounds containing fewer carbon atoms than
  characterize the benzene ring, and in turn yielding open-chain or
  aliphatic compounds. In general, the rupture occurs between a-keto
  group (CO) and a keto-chloride group (CCl2), into which two adjacent
  carbon atoms of the ring are converted by the oxidizing and
  substituting action of chlorine. Decompositions of this nature were
  first discovered in the naphthalene series, where it was found that
  derivatives of indene (and of hydrindene and indone) and also of
  benzene resulted; Zincke then extended his methods to the
  disintegration of the oxybenzenes and obtained analogous results,
  R-pentene and aliphatic derivatives being formed (R- symbolizing a
  ringed nucleus).

  When treated with chlorine, pyrocatechol (1.2 or ortho-dioxybenzene)
  (1) yields a tetrachlor ortho-quinone, which suffers further
  chlorination to hexachlor-o-diketo-R-hexene (2). This substance is
  transformed into hexachlor-R-pentene oxycarboxylic acid (3) when
  digested with water; and chromic acid oxidizes this substance to
  hexachlor-R-pentene (4). The ring of this compound is ruptured by
  caustic soda with the formation of perchlorvinyl acrylic acid (5),
  which gives on reduction ethidine propionic acid (6), a compound
  containing five of the carbon atoms originally in the benzene ring
  (see Zincke, _Ber._, 1894, 27, p. 3364) (the carbon atoms are omitted
  in some of the formulae).

                     Cl             Cl                      Cl
     ^               ^              ^                        ^
   //  \ OH     Cl //  \ O     Cl //  \   /OH           Cl /   \
  |    ||    ==>  |     |  ==>   |     \CO       ==>      |     \CO ==>
  |    ||         |     |        |     /  \CO2H           |     /
   \\  / OH  Cl2   \   / O    Cl2 \   /                Cl2 \   /
     v               v              v                        v
                    Cl2            Cl2                      Cl2

    (1)             (2)            (3)                      (4)

         CCl                 CH2
        // \               /  \
    Cl C    CO2H          CH   CO2H
       |           ==>    ||
    Cl C                  CH
        \\                 \
          CCl2              CH3

         (5)                (6)

  Resorcin (1.3 or meta dioxybenzene) (1) is decomposed in a somewhat
  similar manner. Chlorination in glacial acetic acid solution yields
  pentachlor-m-diketo-R-hexene (2) and, at a later stage,
  heptachlor-m-diketo-R-hexene (3). These compounds are both decomposed
  by water, the former giving dichloraceto-trichlor-crotonic acid (4),
  which on boiling with water gives dichlormethyl-vinyl-a-diketone (5).
  The heptachlor compound when treated with chlorine water gives
  trichloraceto-pentachlorbutyric acid (6), which is hydrolysed by
  alkalis to chloroform and pentachlorglutaric acid (7), and is
  converted by boiling water into tetrachlor-diketo-R-pentene (8). This
  latter compound may be chlorinated to perchloracetoacrylic chloride
  (9), from which the corresponding acid (10) is obtained by treatment
  with water; alkalis hydrolyse the acid to chloroform and dichlormaleic
  acid (11).

     OH               O                     O
     ^                ^                     ^
   /  \\         Cl /   \Cl2           Cl2/   \Cl2
  ||    |     ==>  ||    |      ==>      |     |
  ||    |          ||    |               |     |
   \  // OH        H\   / O            HCl\   / O
     v                v                     v
                     Cl2                   Cl2
    (1)            /       (2)              |    (3)
                  /                         v
                 v             HO2C·CCl2·CHCl·CCl2·CO·CCl3
  HO2C·CCl:CH·CCl2·CO·CHCl2         |    (6)    |
              |  (4)                v           +--------------+
              |                HO2C·CCl2·CHCl·CCl2·CO2H·CHCl3  |
  CO2 + CHHC:CH·CO·CO·CHCl2                 (7)                |
             (5)                         +---------------------+
                                         v
                                  +-- CO·CCl2 \
        ClOC·CCl:CCl·CO·CCl3  <== |             CO (8)
                 | (9)            +-- CCl=CCl /
                 v
        HO2C·CCl:CCl·CO·CCl3 ==> HO2C·CCl:CCl·CO2H + CHCl3
                (10)                      (11)

  Hydroquinone (1.4 or para-dioxybenzene) (1) gives with chlorine,
  first, a tetrachlorquinone (2), and then hexachlor-p-diketo-R-hexene
  (3), which alcoholic potash converts into perchloracroylacrylic acid
  (4). This substance, and also the preceding compound, is converted by
  aqueous caustic soda into dichlormaleic acid, trichlorethylene, and
  hydrochloric acid (5) (Th. Zincke and O. Fuchs, _Ann._, 1892, 267, p.
  1).

     OH           O               COOH          CO2H            CO2H
     ^            ^               ^               ^              /
   //  \     Cl /   \Cl2     ClC//  \Cl2     ClC//  \CCl2     ClC       CCl2
  |    || ==>  ||   ||    ==>  ||   ||    ==>  ||   ||    ==> ||      + ||
  |    ||      ||   ||         ||   ||         ||   ||        ClC       CHCl
   \\  /     Cl \   /Cl2     ClC\   /CCl     ClC\   /CCl         \
     v            v               v               v               CO2H
     OH           O               O              CO

    (1)          (2)              (3)             (4)               (5)

  Phloroglucin (1.3.5-trioxybenzene) (1) behaves similarly to resorcin,
  hexachlor [1.3.5] triketo-R-hexylene (2) being first formed. This
  compound is converted by chlorine water into octachloracetylacetone
  (3); by methyl alcohol into the ester of dichlormalonic acid and
  tetrachloracetone (4); whilst ammonia gives dichloracetamide (5) (Th.
  Zincke and O. Kegel, _Ber._, 1890, 23, p. 1706).

       OH             O
       ^              ^         > (3) Cl2C·CO·CCl2·CO·CCl3·CO2
     /   \       CL2/   \CL2   /
    |     |   ==>  |     |    /
    |     |        |     |    ==> (4) Cl2HC·CO·CHCl2·CH3O2C·CCl2·CO2·CH3
  HO \   / OH     O \   / O   \
       v              v        \
                    CL2         > (5) Cl2C·CONH2

      (1)             (2)


  Reduction in alkaline solution.

  When phenol is oxidized in acid solution by chlorine,
  tetrachlorquinone is obtained, a compound also obtainable from
  hydroquinone. By conducting the chlorination in alkaline solution, A.
  Hantzsch (_Ber._, 1889, 22, p. 1238) succeeded in obtaining
  derivatives of o-diketo-R-hexene, which yield R-pentene and aliphatic
  compounds on decomposition. When thus chlorinated phenol (1) yields
  trichlor-o-diketo-R-hexene (2), which may be hydrolysed to an acid
  (3), which, in turn, suffers rearrangement to
  trichlor-R-pentene-oxycarboxylic acid (4). Bromine water oxidizes this
  substance to oxalic acid and tetrabrom-dichloracetone (5).

    OH             O              HOOC                    /OH
   // \            / \                 \         Cl2C_____C
  //   \       Cl2/   \O       HCl2C    \CO         |     |\COOH
  |    ||  ->    |     |   ->     |     |    ->     |     |
  |    ||        |     |          |     |           |     |
  \\   /        H\\   /H2        HC\\   /CH2      HC\\   /CH2
   \\ /           \\ /              \\ /             \\ /
                    Cl               CCl              CCl

    (1)            (2)               (3)              (4)

       ->  (5)   Cl2BrC·CO·CBr3 + HO2C·CO2H

  The reduction of o-oxybenzoic acids by sodium in amyl alcohol solution
  has been studied by A. Einhorn and J.S. Lumsden (_Ann._, 1895, 286, p.
  257). It is probable that tetrahydro acids are first formed, which
  suffer rearrangement to orthoketone carboxylic acids. These substances
  absorb water and become pimelic acids. Thus salicylic acid yields
  n-pimelic acid, HOOC·(CH2)5·COOH, while o-, m-, and p-cresotinic
  acids, C6H3(CH3)(OH)(COOH), yield isomeric methylpimelic acids.

  Resorcin on reduction gives dihydroresorcin, which G. Merling (_Ann._,
  1894, 278, p. 20) showed to be converted into n-glutaric acid,
  HOOC·(CH2)3·COOH, when oxidized with potassium permanganate; according
  to D. Vörlander (_Ber._, 1895, 28, p. 2348) it is converted into
  [gamma]-acetobutyric acid, CH3CO·(CH2)3·COOH, when heated with baryta
  to 150-160°.

_Configuration of the Benzene Complex._--The development of the
"structure theory" in about 1860 brought in its train an appreciation of
the chemical structure of the derivatives of benzene. The pioneer in
this field was August Kekulé, who, in 1865 (_Ann._, 137, p. 129; see
also his _Lehrbuch der organischen Chemie_), submitted his well-known
formula for benzene, so founding the "benzene theory" and opening up a
problem which, notwithstanding the immense amount of labour since
bestowed upon it, still remains imperfectly solved. Arguing from the
existence of only one mono-substitution derivative, and of three
di-derivatives (statements of which the rigorous proof was then
wanting), he was led to arrange the six carbon atoms in a ring,
attaching a hydrogen atom to each carbon atom; being left with the
fourth carbon valencies, he mutually saturated these in pairs, thus
obtaining the symbol I (see below). The value of this ringed structure
was readily perceived, but objections were raised with respect to
Kekulé's disposal of the fourth valencies. In 1866 Sir James Dewar
proposed an unsymmetrical form (II); while in 1867, A. Claus
(_Theoretische Betrachtungen und deren Anwendung zur Systematik der
organischen Chemie_) proposed his diagonal formula (III), and two years
later, A. Ladenburg (_Ber._, 2, p. 140) devised his prism formula (IV),
the six carbon atoms being placed at the six corners of a right
equilateral triangular prism, with its plane projections (V, VI).

      CH                 CH                  CH
     // \               / | \                /|\
  HC//   \CH         HC/  |  \CH          HC/ | \CH
    |    ||           ||  |  ||             |\|/|
    |    ||           ||  |  ||             | * |
    |    ||           ||  |  ||             |/|\|
  HC\\   /CH         HC\  |  /CH          HC\ | /CH
     \\ /               \ | /                \|/
      CH                 CH                  CH

   I Kekulé            II Dewar            III Claus


  HC+-----+CH            CH                CH
    |\   /|             /|\                /|\
    | \ / |            / | \          HC--/-+-\--CH
    |  |CH|         HC+--+--+CH         \/ \|/ \/
  HC+--|--+CH       HC+--+--+CH         /\ /|\ /\
     \ | /             \ | /          HC--\-+-/--CH
      \|/               \|/                \|/
       CH                CH                CH

      IV                 V                 VI
  \______________________ ________________________/
                         v
                     Ladenburg


  Objections to Kekulé's formula.

  One of the earliest and strongest objections urged against Kekulé's
  formula was that it demanded two isomeric ortho-di-substitution
  derivatives; for if we number the carbon atoms in cyclical order from
  1 to 6, then the derivatives 1·2 and 1·6 should be different.[13]
  Ladenburg submitted that if the 1·2 and 1·6 compounds were identical,
  then we should expect the two well-known crotonic acids,
  CH3·CH:CH·COOH and CH2:CH·CH2·COOH, to be identical. This view was
  opposed by Victor Meyer and Kekulé. The former pointed out that the
  supposed isomerism was not due to an arrangement of atoms, but to the
  disposition of a valency, and therefore it was doubtful whether such a
  subtle condition could exert any influence on the properties of the
  substance. Kekulé answered Ladenburg by formulating a dynamic
  interpretation of valency. He assumed that if we have one atom
  connected by single bonds to (say) four other atoms, then in a
  certain unit of time it will collide with each of these atoms in turn.
  Now suppose two of the attached atoms are replaced by one atom, then
  this atom must have two valencies directed to the central atom; and
  consequently, in the same unit of time, the central atom will collide
  once with each of the two monovalent atoms and twice with the
  divalent. Applying this notion to benzene, let us consider the impacts
  made by the carbon atom (1) which we will assume to be doubly linked
  to the carbon atom (2) and singly linked to (6), h standing for the
  hydrogen atom. In the first unit of time, the impacts are 2, 6, h, 2;
  and in the second 6, 2, h, 6. If we represent graphically the impacts
  in the second unit of time, we perceive that they point to a
  configuration in which the double linkage is between the carbon atoms
  1 and 6, and the single linkage between 1 and 2. Therefore, according
  to Kekulé, the double linkages are in a state of continual
  oscillation, and if his dynamical notion of valency, or a similar
  hypothesis, be correct, then the difference between the 1.2 and 1.6
  di-derivatives rests on the insufficiency of his formula, which
  represents the configuration during one set of oscillations only. The
  difference is only apparent, not real. An analogous oscillation
  prevails in the pyrazol nucleus, for L. Knorr (_Ann._, 1894, 279, p.
  188) has shown that 3- and 5-methylpyrazols are identical.


  Ladenburg's formula.

  The explanation thus attempted by Kekulé was adversely criticized,
  more especially by A. Ladenburg, who devoted much attention to the
  study of the substitution products of benzene, and to the support of
  his own formula. His views are presented in his Pamphlet: _Theorie der
  aromatischen Verbindungen_, 1876. The prism formula also received
  support from the following data: protocatechuic acid when oxidized by
  nitrous acid gives carboxytartronic acid, which, on account of its
  ready decomposition into carbon dioxide and tartronic acid, was
  considered to be HO·C(COOH)3. This implied that in the benzene complex
  there was at least one carbon atom linked to three others, thus
  rendering Kekulé's formula impossible and Ladenburg's and Claus'
  possible. Kekulé (_Ann._, 1883, 221, p. 230), however, reinvestigated
  this acid; he showed that it was dibasic and not tribasic; that it
  gave tartaric acid on reduction; and, finally, that it was
  dioxytartaric acid, HOOC·C(OH)2·C(OH)2·COOH. The formation of this
  substance readily follows from Kekulé's formula, while considerable
  difficulties are met with when one attempts an explanation based on
  Ladenburg's representation. Kekulé also urged that the formation of
  trichlorphenomalic acid, shown by him and O. Strecker to be
  trichloracetoacrylic acid, was more favourably explained by his
  formula than by Ladenburg's.


  Baeyer's researches.

  Other objections to Ladenburg's formula resulted from A. von Baeyer's
  researches (commenced in 1886) on the reduced phthalic acids. Baeyer
  pointed out that although benzene derivatives were obtainable from
  hexamethylene compounds, yet it by no means follows that only
  hexamethylene compounds need result when benzene compounds are
  reduced. He admitted the possibility of the formulae of Kekulé, Claus,
  Dewar and Ladenburg, although as to the last di-trimethylene
  derivatives should be possible reduction products, being formed by
  severing two of the prism edges; and he attempted to solve the problem
  by a systematic investigation of the reduced phthalic acids.

            CO              C·OH             C·OH                 (1)OH
           / \              // \              // \                 / | \
       H2C/   \CH·CO2Et  HC//   \CH·CO2Et  HC//   \C·CO2Et        /  |  \
          |   |            |    |            |    ||    EtO2C·(6)|---+---|(5)H
          |   |      or    |    |      -->   |    ||             |   |   |
          |   |            |    |            |    ||    EtO2C·(3)|---+---|(2)OH
  EtO2C·HC\   /CH2  EtO2C·C\\   /CH2  EtO2C·C\\   /CH             \  |  /
           \ /              \\ /              \\ /                 \ | /
           CO               C·OH              C·OH                 (4)H

           I                 II                III                   IV

  Ladenburg's prism admits of one mono-substitution derivative and three
  di-derivatives. Furthermore, it is in accordance with certain simple
  syntheses of benzene derivatives (e.g. from acetylene and acetone);
  but according to Baeyer (_Ber._, 1886, 19, p. 1797) it fails to
  explain the formation of dioxyterephthalic ester from succinosuccinic
  ester, unless we make the assumption that the transformation of these
  substances is attended by a migration of the substituent groups. For
  succinosuccinic ester, formed by the action of sodium on two molecules
  of succinic ester, has either of the formulae (I) or (II); oxidation
  of the free acid gives dioxyterephthalic acid in which the
  para-positions must remain substituted as in (I) and (II). By
  projecting Ladenburg's prism on a plane and numbering the atoms so as
  to correspond with Kekulé's form, viz. that 1.2 and 1.6 should be
  ortho-positions, 1.3 and 1.5 meta-, and 1.4 para-, and following out
  the transformation on the Ladenburg formula, then an
  ortho-dioxyterephthalic acid (IV) should result, a fact denied by
  experience, and inexplicable unless we assume a wandering of atoms.
  Kekulé's formula (III), on the other hand, is in full agreement
  (Baeyer). This explanation has been challenged by Ladenburg (_Ber._,
  1886, 19, p. 971; _Ber._, 1887, 20, p. 62) and by A.K. Miller (_J.C.S.
  Trans._, 1887, p. 208). The transformation is not one of the oxidation
  of a hexamethylene compound to a benzenoid compound, for only two
  hydrogen atoms are removed. Succinosuccinic ester behaves both as a
  ketone and as a phenol, thereby exhibiting desmotropy; assuming the
  ketone formula as indicating the constitution, then in Baeyer's
  equation we have a migration of a hydrogen atom, whereas to bring
  Ladenburg's formula into line, an oxygen atom must migrate.

  The relative merits of the formulae of Kekulé, Claus and Dewar were
  next investigated by means of the reduction products of benzene, it
  being Baeyer's intention to detect whether double linkages were or
  were not present in the benzene complex.

  To follow Baeyer's results we must explain his nomenclature of the
  reduced benzene derivatives. He numbers the carbon atoms placed at the
  corners of a hexagon from 1 to 6, and each side in the same order, so
  that the carbon atoms 1 and 2 are connected by the side 1, atoms 2 and
  3 by the side 2, and so on. A doubly linked pair of atoms is denoted
  by the sign [DELTA] with the index corresponding to the side; if there
  are two pairs of double links, then indices corresponding to both
  sides are employed. Thus [DELTA]^1 denotes a tetrahydro derivative in
  which the double link occupies the side 1; [DELTA]^{1.3}, a dihydro
  derivative, the double links being along the sides 1 and 3. Another
  form of isomerism is occasioned by spatial arrangements, many of the
  _reduced_ terephthalic acids existing in two stereo-isomeric forms.
  Baeyer explains this by analogy with fumaric and maleic acids: he
  assumes the reduced benzene ring to lie in a plane; when both carboxyl
  groups are on the same side of this plane, the acids, in general,
  resemble maleic acids, these forms he denotes by [GAMMA]_cis-cis_, or
  shortly _cis_-; when the carboxyl groups are on opposite sides, the
  acids correspond to fumaric acid, these forms are denoted by
  [GAMMA]_cis-trans_, or shortly _trans_-.

  By reducing terephthalic acid with sodium amalgam, care being taken to
  neutralize the caustic soda simultaneously formed by passing in carbon
  dioxide, [DELTA]^{2.5} dihydroterephthalic acid is obtained; this
  results from the splitting of a _para_-linkage. By boiling with water
  the [DELTA]^{2.5} acid is converted into the [DELTA]^{1.5}
  dihydroterephthalic acid. This acid is converted into the
  [DELTA]^{1.4} acid by soda, and into the [DELTA]^2 tetrahydro acid by
  reduction. From this acid the [DELTA]^{1.3} dihydro and the [DELTA]^1
  tetrahydro acids may be obtained, from both of which the hexahydro
  acid may be prepared. From these results Baeyer concluded that Claus'
  formula with three para-linkings cannot possibly be correct, for the
  [DELTA]^{2.5} dihydroterephthalic acid undoubtedly has two ethylene
  linkages, since it readily takes up two or four atoms of bromine, and
  is oxidized in warm aqueous solution by alkaline potassium
  permanganate. But the formation of the [DELTA]^{2.5} acid as the first
  reduction product is not fully consistent with Kekulé's symbol, for we
  should then expect the [DELTA]^{1.3} or the [DELTA]^{1.5} acid to be
  first formed (see also POLYMETHYLENES).

The stronger argument against the ethylenoid linkages demanded by
Kekulé's formula is provided by the remarkable stability towards
oxidizing and reducing agents which characterizes all benzenoid
compounds. From the fact that reduction products containing either one
or two double linkages behave exactly as unsaturated aliphatic
compounds, being readily reduced or oxidized, and combining with the
halogen elements and haloid acids, it seems probable that in benzenoid
compounds the fourth valencies are symmetrically distributed in such a
manner as to induce a peculiar stability in the molecule. Such a
configuration was proposed in 1887 by H.E. Armstrong (_J.C.S. Trans._,
1887, p. 258), and shortly afterwards by Baeyer (_Ann._, 1888, 245, p.
103). In this formula, the so-called "centric formula," the assumption
made is that the fourth valencies are simply _directed_ towards the
centre of the ring; nothing further is said about the fourth valencies
except that they exert a pressure towards the centre. Claus maintained
that Baeyer's view was identical with his own, for as in Baeyer's
formula, the fourth valencies have a different function from the
peripheral valencies, being united at the centre in a form of potential
union.

It is difficult to determine which configuration most accurately
explains the observed facts; Kekulé's formula undoubtedly explains the
synthetical production of benzenoid compounds most satisfactorily, and
W. Marckwald (_Ann._, 1893, 274, p. 331; 1894, 279, p. 14) has supported
this formula from considerations based on the syntheses of the quinoline
ring. Further researches by Baeyer, and upon various nitrogenous ring
systems by E. Bamberger (a strong supporter of the centric formula),
have shown that the nature of the substituent groups influences the
distribution of the fourth valencies; therefore it may be concluded that
in compounds the benzene nucleus appears to be capable of existence in
two tautomeric forms, in the sense that each particular derivative
possesses a definite constitution. The benzene nucleus presents a
remarkable case, which must be considered in the formulation of any
complete theory of valency. From a study of the reduction of compounds
containing two ethylenic bonds united by a single bond, termed a
"conjugated system," E. Thiele suggested a doctrine of "partial
valencies," which assumes that in addition to the ordinary valencies,
each doubly linked atom has a partial valency, by which the atom first
interacts. When applied to benzene, a twofold conjugated system is
suggested in which the partial valencies of adjacent atoms neutralize,
with the formation of a potential double link. The stability of benzene
is ascribed to this conjugation.[14]


  Physico-chemical methods.

Physico-chemical properties have also been drawn upon to decide whether
double unions are present in the benzene complex; but here the
predilections of the observers apparently influence the nature of the
conclusions to be drawn from such data. It is well known that singly,
doubly and trebly linked carbon atoms affect the physical properties of
substances, such as the refractive index, specific volume, and the heat
of combustion; and by determining these constants for many substances,
fairly definite values can be assigned to these groupings. The general
question of the relation of the refractive index to constitution has
been especially studied by J.W. Brühl, who concluded that benzene
contained 3 double linkages; whereas, in 1901, Pellini (_Gazetta_, 31,
i. p. 1) calculated that 9 single linkages were present. A similar
contradiction apparently exists with regard to the specific volume, for
while benzene has a specific volume corresponding to Claus' formula,
toluene, or methylbenzene, rather points to Kekulé's. The heat of
combustion, as first determined by Julius Thomsen, agreed rather better
with the presence of nine single unions. His work was repeated on a
finer scale by M.P.E. Berthelot of Paris, and F.C.A. Stohmann of
Leipzig; and the new data and the conclusions to be drawn from them
formed the subject of much discussion, Brühl endeavouring to show how
they supported Kekulé's formula, while Thomsen maintained that they
demanded the benzene union to have a different heat of combustion from
the acetylene union. Thomsen then investigated heats of combustion of
various benzenoid hydrocarbons--benzene, naphthalene, anthracene,
phenanthrene, &c.--in the crystallized state. It was found that the
results were capable of expression by the empirical relation C_{a}H_{2b}
= 104.3b + 49.09m + 105.47n, where C_{a}H_{2b} denotes the formula of
the hydrocarbon, m the number of single carbon linkings and n the number
of double linkings, m and n being calculated on the Kekulé formulae.
But, at the same time, the constants in the above relation are not
identical with those in the corresponding relation empirically deduced
from observations on fatty hydrocarbons; and we are therefore led to
conclude that a benzene union is considerably more stable than an
ethylene union.

Mention may be made of the absorption spectrum of benzene. According to
W.N. Hartley (_J.C.S._, 1905, 87, p. 1822), there are six bands in the
ultra-violet, while E.C.C. Baly and J.N. Collie (_J.C.S._, 1905, 87, p.
1332; 1906, 89, p. 524) record seven. These bands are due to molecular
oscillations; Hartley suggests the carbon atoms to be rotating and
forming alternately single and double linkages, the formation of three
double links giving three bands, and of three single links another
three; Baly and Collie, on the other hand, suggest the making and
breaking of links between adjacent atoms, pointing out that there are
seven combinations of one, two and three pairs of carbon atoms in the
benzene molecule.

_Stereo-chemical Configurations._--Simultaneously with the discussions
of Kekulé, Ladenburg, Claus, Baeyer and others as to the merits of
various plane formulae of the benzene complex, there were published many
suggestions with regard to the arrangement of the atoms in space, all of
which attempted to explain the number of isomers and the equivalence of
the hydrogen atoms. The development of stereo-isomerism at the hands of
J. Wislicenus, Le Bel and van 't Hoff has resulted in the introduction
of another condition which formulae for the benzene complex must
satisfy, viz. that the hydrogen atoms must all lie in one plane. The
proof of this statement rests on the fact that if the hydrogen atoms
were not co-planar, then substitution derivatives (the substituting
groups not containing asymmetric carbon atoms) should exist in
enantiomorphic forms, differing in crystal form and in their action on
polarized light; such optical antipodes have, however, not yet been
separated. Ladenburg's prism formula would give two enantiomorphic
ortho-di-substitution derivatives; while forms in which the hydrogen
atoms are placed at the corners of a regular octahedron would yield
enantiomorphic tri-substitution derivatives.

  The octahedral formula discussed by Julius Thomsen (_Ber._, 1886, 19,
  p. 2944) consists of the six carbon atoms placed at the corners of a
  regular octahedron, and connected together by the full lines as shown
  in (I); a plane projection gives a hexagon with diagonals (II).
  Reduction to hexamethylene compounds necessitates the disruption of
  three of the edges of the octahedron, the diagonal linkings remaining
  intact, or, in the plane projection, three peripheral linkages, the
  hexamethylene ring assuming the form (III):

  [Illustration: I II III]

  In 1888 J.E. Marsh published a paper (_Phil. Mag._ [V.], 26, p. 426)
  in which he discussed various stereo-chemical representations of the
  benzene nucleus. (The stereo-chemistry of carbon compounds has led to
  the spatial representation of a carbon atom as being situated at the
  centre of a tetrahedron, the four valencies being directed towards the
  apices; see above, and ISOMERISM.) A form based on Kekulé's formula
  consists in taking three pairs of tetrahedra, each pair having a side
  in common, and joining them up along the sides of a regular hexagon by
  means of their apices. This form, afterwards supported by Carl Graebe
  (_Ber._, 1902, 35, p. 526; see also Marsh's reply, _Journ. Chem. Soc.
  Trans._, 1902, p. 961) shows the proximity of the ortho-positions, but
  fails to explain the identity of 1·2 and 1·6 compounds. Arrangements
  connected with Claus' formula are obtained by placing six tetrahedra
  on the six triangles formed by the diagonals of a plane hexagon. The
  form in which the tetrahedra are all on one side, afterwards discussed
  by J. Loschmidt (_Monats._, 1890, II, p. 28), would not give
  stereo-isomers; and the arrangement of placing the tetrahedra on
  alternate sides, a form afterwards developed by W. Vaubel (_Journ. Pr.
  Chem._, 1894[2], 49, p. 308), has the advantage of bringing the
  meta-positions on one side, and the ortho- and para- on opposite
  sides, thus exhibiting the similarity actually observed between these
  series of compounds. Marsh also devised a form closely resembling that
  of Thomsen, inasmuch as the carbon atoms occupied the angles of a
  regular octahedron, and the diagonal linkages differed in nature from
  the peripheral, but differing from Thomsen's since rupture of the
  diagonal and not peripheral bonds accompanied the reduction to
  hexamethylene.

  We may also notice the model devised by H. Sachse (_Ber._, 1888, 21,
  2530; _Zeit. fur phys. Chem._, II, p. 214; 23, p. 2062). Two parallel
  triangular faces are removed from a cardboard model of a regular
  octahedron, and on the remaining six faces tetrahedra are then placed;
  the hydrogen atoms are at the free angles. This configuration is,
  according to Sachse, more stable than any other form; no oscillation
  is possible, the molecule being only able to move as a whole. In 1897,
  J.N. Collie (_Journ. Chem. Soc. Trans._, p. 1013) considered in detail
  an octahedral form, and showed how by means of certain simple
  rotations of his system the formulae of Kekulé and Claus could be
  obtained as projections. An entirely new device, suggested by B. König
  (_Chem. Zeit._, 1905, 29, p. 30), assumed the six carbon atoms to
  occupy six of the corners of a cube, each carbon atom being linked to
  a hydrogen atom and by single bonds to two neighbouring carbon atoms,
  the remaining valencies being directed to the unoccupied corners of
  the cube, three to each, where they are supposed to satisfy each
  other.

_Condensed Nuclei._

Restricting ourselves to compounds resulting from the fusion of benzene
rings, we have first to consider naphthalene, C10H8, which consists of
two benzene rings having a pair of carbon atoms in common. The next
members are the isomers anthracene and phenanthrene, C14H10, formed from
three benzene nuclei. Here we shall only discuss the structure of these
compounds in the light of the modern benzene theories; reference should
be made to the articles NAPHTHALENE, ANTHRACENE and PHENANTHRENE for
syntheses, decompositions, &c.

_Naphthalene._--Of the earlier suggestions for the constitution of
naphthalene we notice the formulae of Wreden (1) and (2), Berthelot and
Balls (3), R.A.C.E. Erlenmeyer (4) and Adolf Claus (5).

    //\                //\    /|\         /|\    /|\        //\    /\\
   //  \              //  \  / | \       / | \  / | \      //  \  /  \\
  //    \ __CH2      //    \/  |  \     /  |  \/  |  \    //    \/    \\
  |     ||  |        |     ||  |  ||   ||  |  ||  |  ||   |     ||     |
  |     ||  | /||CH  |     ||  |  ||   ||  |  ||  |  ||   |     ||     |
  |     ||  |/ ||    |     ||  |  ||   ||  |  ||  |  ||   |     ||     |
  \\    /---C  ||    \\    /\  |  /     \  |  /\  |  /    \\    /\    //
   \\  /     \ ||     \\  /  \ | /       \ | /  \ | /      \\  /  \  //
    \\/       \||CH    \\/    \|/         \|/    \|/        \\/    \//

        (1)               (2)                (3)               (4)

    /|\   /|\
   / | \ / | \
  |\ | /|  | ||
  | \|/ |  | ||
  |  |  |  | ||
  | /|\ |  | ||
  |/ | \|  | ||
   \ | / \ | /
    \|/   \|/

       (5)

The first suggestion is quite out of the question. C. Graebe in 1866
(_Ann._ 149, p. 20) established the symmetry of the naphthalene nucleus,
and showed that whichever half of the molecule be oxidized the same
phthalic acid results. Therefore formula (2), being unsymmetrical, is
impossible. The third formula is based on Dewar's benzene formula, which
we have seen to be incorrect. Formula (4) is symmetrical and based on
Kekulé's formula: it is in full accord with the syntheses and
decompositions of the naphthalene nucleus and the number of isomers
found. In 1882 Claus suggested a combination of his own and Dewar's
benzene formulae. This is obviously unsymmetrical, consisting of an
aliphatic and an aromatic nucleus; Claus explained the formation of the
same phthalic acid from the oxidation of either nucleus by supposing
that if the aromatic group be oxidized, the aliphatic residue assumes
the character of a benzene nucleus. Bamberger opposed Claus' formula on
the following grounds:--The molecule of naphthalene is symmetrical,
since 2.7 dioxynaphthalene is readily esterified by methyl iodide and
sulphuric acid to a dimethyl ether; and no more than two
mono-substitution derivatives are known. The molecule is aromatic but
not benzenoid; however, by the reduction of one half of the molecule,
the other assumes a benzenoid character.

  If [beta]-naphthylamine and [beta]-naphthol be reduced, tetrahydro
  products are obtained in which the amino- or oxy-bearing half of the
  molecule becomes aliphatic in character. The compounds so obtained,
  alicyclic-[beta]-tetrahydronaphthylamine and
  alicyclic-[beta]-tetrahydronaphthol, closely resemble
  [beta]-aminodiethylbenzene, C6H4(C2H5)·C2H4NH2, and
  [beta]-oxydiethylbenzene, C6H4(C2H5)·C2H4OH. If [alpha]-naphthylamine
  and [alpha]-naphthol be reduced, the hydrogen atoms attach themselves
  to the non-substituted half of the molecule, and the compounds so
  obtained resemble aminodiethylbenzene, C6H3·NH2(C2H5)2 and
  oxydiethylbenzene, C6H3·OH(C2H5)2. Bamberger's observations on reduced
  quinoline derivatives point to the same conclusion, that condensed
  nuclei are not benzenoid, but possess an individual character, which
  breaks down, however, when the molecule is reduced.

It remains, therefore, to consider Erlenmeyer's formula and those
derived from the centric hypothesis. The former, based on Kekulé's
symbol for benzene, explains the decompositions and syntheses of the
ring, but the character of naphthalene is not in keeping with the
presence of five double linkages, although it is more readily acted upon
than benzene is. On the centric hypothesis two formulae are possible:
(i) due to H.E. Armstrong, and (2) due to E. Bamberger.

    /|\   /|\        /|\   /|\
   /   \ /   \      /   \ /   \
  |\   -|-   /|    |\    X    /|
  |     |     |    |    / \    |
  |     |     |    |           |
  |     |     |    |    \ /    |
  |/   -|-   \|    |/    X    \|
   \   / \   /      \   / \   /
    \|/   \|/        \|/   \|/

       (1)              (2)

In the first symbol it is assumed that one of the affinities of each of
the two central carbon atoms common to the two rings _acts into_ both
rings, an assumption involving a somewhat wide departure from all
ordinary views as to the manner in which affinity acts. This symbol
harmonizes with the fact that the two rings are in complete sympathy, the
one responding to every change made in the other. Then, on account of the
relatively slight--because divided--influence which would be exercised
upon the two rings by the two affinities common to both, the remaining
four centric affinities of each ring would presumably be less attracted
into the ring than in the case of benzene; consequently they would be
more active outwards, and combination would set in more readily. When, as
in the formation of naphthalene tetrachloride, for example, the one ring
becomes saturated, the other might be expected to assume the normal
centric form and become relatively inactive. This is absolutely the
case. On the other hand, if substitution be effected in the one ring, and
the affinities in that ring become attracted inwards, as apparently
happens in the case of benzene, the adjoining ring should become
relatively more active because the common affinities would act less into
it. Hence, unless the radical introduced be one which exercises a special
attractive influence, substitution should take place in preference in the
previously unsubstituted ring. In practice this usually occurs; for
example, on further bromination, [alpha]-bromonaphthalene yields a
mixture of the (1.4) and (1.5) dibromonaphthalenes; and when
nitronaphthalene is either brominated, or nitrated or sulphonated, the
action is practically confined to the second ring. The centric formula
proposed by Bamberger represents naphthalene as formed by the fusion of
two benzene rings, this indicates that it is a monocyclic composed of ten
atoms of carbon. The formula has the advantage that it may be constructed
from tetrahedral models of the carbon atom; but it involves the
assumption that the molecule has within it a mechanism, equivalent in a
measure to a system of railway points, which can readily close up and
pass into that characteristic of benzene.

_Anthracene and Phenanthrene._--These isomeric hydrocarbons, of the
formula C14H10, are to be regarded as formed by the fusion of three
benzenoid rings as represented by the symbols:--

                               ____
    /\   /\   /\              /    \
   /  \ /  \ /  \        ____/      \____
  |    |    |    |      /    \      /    \
  |    |    |    |     /      \____/      \
   \  / \  / \  /      \      /    \      /
    \/   \/   \/        \____/      \____/

     Anthracene            Phenanthrene

In both cases the medial ring is most readily attacked; and various
formulae have been devised which are claimed by their authors to
represent this and other facts. According to Armstrong, anthracene
behaves unsymmetrically towards substituents, and hence one lateral ring
differs from the other; he represents the molecule as consisting of one
centric ring, the remaining medial and lateral ring being ethenoid.
Bamberger, on the other hand, extends his views on benzene and
naphthalene and assumes the molecule to be (1). For general purposes,
however, the symbol (2), in which the lateral rings are benzenoid and
the medial ring fatty, represents quite adequately the syntheses,
decompositions, and behaviour of anthracene.

    /|\   /|\   /|\        / \   /|\   / \
   /   \ /   \ /   \      /   \ / | \ /   \
  |\    X     X    /|    |     |  |  |     |
  |    / \   / \    |    |     |  |  |     |
  |                 |    |     |  |  |     |
  |    \ /   \ /    |    |     |  |  |     |
  |/    X     X    \|    |     |  |  |     |
   \   / \   / \   /      \   / \ | / \   /
    \|/   \|/   \|/        \ /   \|/   \ /

          (1)                    (2)

Phenanthrene is regarded by Armstrong as represented by (3), the lateral
rings being benzenoid, and the medial ring fatty; Bamberger, however,
regards it as (4), the molecule being entirely aromatic. An interesting
observation by Baeyer, viz. that stilbene, C6H5·CH:CH·C6H5, is very
readily oxidized, while phenanthrene is not, supports, in some measure,
the views of Bamberger.

          ____                    ____
         /----\                  /\  /\
    ____/      \____        ____/_    _\____
   /    \      /    \      /\  /        \  /\
  /      \____/      \    /     __/__\__     \
  \      /    \      /    \      /    \      /
   \____/      \____/      \/__\/      \/__\/

          (3)                     (4)

_Heterocyclic Compounds._

During recent years an immense number of ringed or cyclic compounds have
been discovered, which exhibit individual characters more closely
resembling benzene, naphthalene, &c. than purely aliphatic substances,
inasmuch as in general they contain double linkages, yet withstand
oxidation, and behave as nuclei, forming derivatives in much the same
way as benzene. By reduction, the double linkages become saturated, and
compounds result which stand in much about the same relation to the
original nucleus as hexamethylene does to benzene. In general,
therefore, it may be considered that the double linkages are not of
exactly the same nature as the double linkage present in ethylene and
ethylenoid compounds, but that they are analogous to the potential
valencies of benzene. The centric hypothesis has been applied to these
rings by Bamberger and others; but as in the previous rings considered,
the ordinary representation with double and single linkages generally
represents the syntheses, decompositions, &c.; exceptions, however, are
known where it is necessary to assume an oscillation of the double
linkage. Five- and six-membered rings are the most stable and important,
the last-named group resulting from the polymerization of many
substances; three- and four-membered rings are formed with difficulty,
and are easily ruptured; rings containing seven or more members are
generally unstable, and are relatively little known. The elements which
go to form heterocyclic rings, in addition to carbon, are oxygen,
sulphur, selenium and nitrogen. It is remarkable that sulphur can
replace two methine or CH groups with the production of compounds
greatly resembling, the original one. Thus benzene, (CH)6, gives
thiophene, (CH)4S, from which it is difficultly distinguished; pyridine,
(CH)5N, gives thiazole, (CH)3·N·S, which is a very similar substance;
naphthalene gives thionaphthen, C8H6S, with which it shows great
analogies, especially in the derivatives. Similarly a CH group may be
replaced by a nitrogen atom with the production of compounds of similar
stability; thus benzene gives pyridine, naphthalene gives quinoline and
isoquinoline; anthracene gives acridine and [alpha] and [beta]
anthrapyridines. Similarly, two or more methine groups may be replaced
by the same number of nitrogen atoms with the formation of rings of
considerable stability.

  Most of the simple ring systems which contain two adjacent carbon
  atoms may suffer fusion with any other ring (also containing two
  adjacent carbon atoms) with the production of nuclei of greater
  complexity. Such _condensed nuclei_ are, in many cases, more readily
  obtained than the parent nucleus. The more important types are derived
  from aromatic nuclei, benzene, naphthalene, &c.; the
  ortho-di-derivatives of the first named, lending themselves
  particularly to the formation of condensed nuclei. Thus
  ortho-phenylene diamine yields the following products:--

    /\   N          /\   N          /\   N
   /  \ /\\        /  \ /\\        /  \ /|\
  |    |  \\      |    |  \\      |    | | \
  |    |   CH     |    |   N      |    | |  S
  |    |   /      |    |   /      |    | | /
   \  / \ /        \  / \ /        \  / \|/
    \/   NH  ,      \/   NH ,       \/   N   ,

  Benzimidazole  Azimidobenzene  Benzpiazthiole

    /\   NH            /\   NH          /\   N
   /  \ / \           /  \ /\\         /  \ /\\
  |    |   \         |    |  \\       |    |  CH
  |    |    >CO  or  |    |   C·OH    |    |  |
  |    |   /         |    |   /       |    |  CH
   \  / \ /           \  / \ /         \  / \//
    \/   NH            \/   NH    ,     \/   N

  \_______________________________/
           Benzimidazolone            Quinoxaline

  In some cases oxidation of condensed benzenoid-heterocyclic nuclei
  results in the rupture of the heterocyclic ring with the formation of
  a benzene dicarboxylic acid; but if the aromatic nucleus be weakened
  by the introduction of an amino group, then it is the benzenoid
  nucleus which is destroyed and a dicarboxylic acid of the heterocyclic
  ring system obtained.

Heterocyclic rings may be systematically surveyed from two aspects: (1)
by arranging the rings with similar hetero-atoms according to the
increasing number of carbon atoms, the so-called "homologous series"; or
(2) by first dividing the ring systems according to the number of
members constituting the ring, and then classifying these groups
according to the nature of the hetero-atoms, the so-called "isologous
series." The second method possesses greater advantages, for rings of
approximate stability come in one group, and, consequently, their
derivatives may be expected to exhibit considerable analogies.

As a useful preliminary it is convenient to divide heterocyclic ring
systems into two leading groups: (1) systems resulting from simple
internal dehydration (or similar condensations) of saturated aliphatic
compounds--such compounds are: the internal anhydrides or cyclic ethers
of the glycols and thioglycols (ethylene oxide, &c.); the cyclic
alkyleneimides resulting from the splitting off of ammonia between the
amino groups of diamino-paraffins (pyrrolidine, piperazine, &c.); the
cyclic esters of oxycarboxylic acids (lactones, lactides); the internal
anhydrides of aminocarboxylic acids (lactams, betaines); cyclic
derivatives of dicarboxylic acids (anhydrides, imides, alkylen-esters,
alkylen-amides, &c.). These compounds retain their aliphatic nature, and
are best classified with open-chain compounds, into which, in general,
they are readily converted. (2) Systems which are generally unsaturated
compounds, often of considerable stability, and behave as nuclei; these
compounds constitute a well-individualized class exhibiting closer
affinities to benzenoid substances than to the open-chain series.

  The transition between the two classes as differentiated above may be
  illustrated by the following cyclic compounds, each of which contains
  a ring composed of four carbon atoms and one oxygen atom:

    CH2·CH2\        CH2·CO \       CH2·CO\        CH·CO\        CH=CH\
    |       O       |       O      |      O       ||    O       |     O
    CH2·CH2/        CH2·CH2/       CH2·CO/        CH·CO/        CH=CH/

  Tetramethylene  Butyrolactone.   Succinic        Maleic       Furfurane.
      oxide.                      anhydride.     anhydride.

  The first four substances are readily formed from, and converted into,
  the corresponding dihydroxy open-chain compound; these substances are
  truly aliphatic in character. The fifth compound, on the other hand,
  does not behave as an unsaturated aliphatic compound, but its
  deportment is that of a nucleus, many substitution derivatives being
  capable of synthesis. Reduction, however, converts it into an
  aliphatic compound. This is comparable with the reduction of the
  benzene nucleus into hexamethylene, a substance of an aliphatic
  character.

True ring systems, which possess the characters of organic nuclei, do
not come into existence in three-and four-membered rings, their first
appearance being in penta-atomic rings. The three primary members are
furfurane, thiophene and pyrrol, each of which contains four methine or
CH groups, and an oxygen, sulphur and imido (NH) member respectively; a
series of compounds containing selenium is also known. The formulae of
these substances are:

   CH=CH\        CH=CH\        CH=CH\       CH=CH\
   |     O       |     S       |     Se     |     NH
   CH=CH/        CH=CH/        CH=CH/       CH=CH/

  Furfurane.    Thiophene.   Selenophene.   Pyrrol.

By substituting one or more CH groups in these compounds by nitrogen
atoms, ring-systems, collectively known as _azoles_, result. Obviously,
isomeric ring-systems are possible, since the carbon atoms in the
original rings are not all of equal value. Thus furfurane yields the
following rings by the introduction of one and two nitrogen atoms:

   CH==N\        N==CH\        N===N\
   |     O       |     O       |     O
   CH=CH/        CH=CH/        CH=CH/

  Isoxazole.     Oxazole.    Diazo-oxides.

   CH=N\         N=CH\         N=CH\
   |    O        |    O        |    O
   CH=N/         CH=N/         N=CH/

  Furazane.     Azoximes.    Oxybiazole.

Thiophene yields a similar series: isothiazole (only known as the
condensed ring, isobenzothiazole), thiazole, diazosulphides,
piazthioles, azosulphimes and thiobiazole (the formulae are easily
derived from the preceding series by replacing oxygen by sulphur).
Thiophene also gives rise to triazsulphole, three nitrogen atoms being
introduced. Selenophene gives the series: selenazole, diazoselenide and
piaselenole, corresponding to oxazole, diazo-oxides and furazane. Pyrrol
yields an analogous series: pyrazole, imidazole or glyoxaline, azimide
or osotriazole, triazole and tetrazole:

   CH==N\        N==CH\       N===N\
   |     NH      |     NH     |     NH
   CH=CH/        CH=CH/       CH=CH/

  Pyrazole.     Imidazole.   Azimide.

          N=CH\        N==N\
          |    NH      |    NH
          N=CH/        N=CH/

         Triazole.    Tetrazole.

Six-membered ring systems can be referred back, in a manner similar to
the above, to pyrone, penthiophene and pyridine, the substances
containing a ring of five carbon atoms, and an oxygen, sulphur and
nitrogen atom respectively. As before, only _true_ ring nuclei, and not
internal anhydrides of aliphatic compounds, will be mentioned. From the
pyrone ring the following series of compounds are derived (for brevity,
the hydrogen atoms are not printed):

      C             C              C             N             C
     / \           / \            / \           / \           / \
  C /   \ C     C /   \ C      C /   \ N     C /   \ C     C /   \ C
   |     |       |     |        |     |       |     |       |     |
   |     |       |     |        |     |       |     |       |     |
  C \   / C     C \   / N      C \   / C     C \   / C     N \   / N
     \ /           \ /            \ /           \ /           \ /
      O             O              O             O             O

    Pyrone   Ortho-oxazine   Meta-oxazine   Paroxazine     Azoxazine
                           or pentoxazoline

Penthiophene gives, by a similar introduction of nitrogen atoms,
penthiazoline, corresponding to meta-oxazine, and para-thiazine,
corresponding to paroxazine (para-oxazine). Pyridine gives origin to:
pyridazine or ortho-diazine, pyrimidine or meta-diazine, pyrazine or
para-diazine, osotriazine, _unsymmetrical_ triazine, _symmetrical_
triazine, osotetrazone and tetrazine. The skeletons of these types are
(the carbon atoms are omitted for brevity):

                                          N
    / \         / \          / \         / \
   /   \       /   \        /   \ N     /   \
  |     |     |     |      |     |     |     |
  |     |     |     |      |     |     |     |
   \   /       \   / N      \   /       \   /
    \ /         \ /          \ /         \ /
     N           N            N           N

  Pyridine   Pyridazine   Pyrimidine   Pyrazine


     / \         / \          / \
    /   \     N /   \      N /   \ N
   |     |     |     |      |     |
   |     |     |     |      |     |
  N \   / N     \   / N      \   /
     \ /         \ /          \ /
      N           N            N
  \________________________________/
              Triazines

       N            N
      / \          / \
     /   \ N    N /   \
    |     |      |     |
    |     |      |     |
     \   / N      \   / N
      \ /          \ /
       N            N

  Osotetrazone  Tetrazone

We have previously referred to the condensation of heterocyclic ring
systems containing two vicinal carbon atoms with benzene, naphthalene
and other nuclei. The more important nuclei of this type have received
special and non-systematic names; when this is not the case, such terms
as phen-, benzo-, naphtho- are prefixed to the name of the heterocyclic
ring. One or two benzene nuclei may suffer condensation with the
furfurane, thiophene and pyrrol rings, the common carbon atoms being
vicinal to the hetero-atom. The mono-benzo-derivatives are coumarone,
benzothiophene and indole; the dibenzo-derivatives are diphenylene
oxide, dibenzothiophene or diphenylene sulphide, and carbazole. Typical
formulae are (R denoting O, S or NH):

    /\             /\        /\
   /  \ ____      /  \ ____ /  \
  |    |    |    |    |    |    |
  |    |    |    |    |    |    |
   \  / \  /      \  / \  / \  /
    \/   \/  ,     \/   \/   \/
         R              R

Isomers are possible, for the condensation may be effected on the two
carbon atoms symmetrically placed to the hetero-atom; these isomers,
however, are more of the nature of internal anhydrides. Benz-oxazoles
and -thiazoles have been prepared, benz-isoxazoles are known as
indoxazenes; benzo-pyrazoles occur in two structural forms, named
indazoles and isindazoles. Derivatives of osotriazol also exist in two
forms--azimides and pseudo-azimides.

Proceeding to the six-membered hetero-atomic rings, the benzo-,
dibenzo-and naphtho-derivatives are frequently of great commercial and
scientific importance, [alpha]-pyrone condenses with the benzene ring to
form coumarin and isocoumarin; benzo-[gamma]-pyrone constitutes the
nucleus of several vegetable colouring matters (chrysin, fisetin,
quercetin, &c., which are derivatives of flavone or phenyl
benzo-[gamma]-pyrone); dibenzo-[gamma]-pyrone is known as xanthone;
related to this substance are fluorane (and fluorescein), fluorone,
fluorime, pyronine, &c. The pyridine ring condenses with the benzene ring
to form quinoline and isoquinoline; acridine and phenanthridine are
dibenzo-pyridines; naphthalene gives rise to [alpha]- and
[beta]-naphthoquinolines and the anthrapyridines; anthracene gives
anthraquinoline; while two pyridine nuclei connected by an intermediate
benzene nucleus give the phenanthrolines. Naphthyridines and
naphthinolines result from the condensation of two pryridine and two
quinoline nuclei respectively; and quino-quinolines are unsymmetrical
naphthyridine nuclei condensed with a benzene nucleus.
Benzo-orthoxazines, -metoxazines and -paroxazines are known:
dibenzoparoxazine or phenoxazine is the parent of a valuable series of
dyestuffs; dibenzoparathiazine or thiodiphenylamine is important from the
same aspect. Benzo-ortho-diazines exist in two structural forms, cinnolin
and phthalazine; benzo-meta-diazines are known as quinazolines;
benzo-para-diazines are termed quinoxalines; the dibenzo-compounds are
named phenazines, this last group including many valuable
dyestuffs--indulines, safranines, &c. In addition to the types of
compounds enumerated above we may also notice purin, tropine and the
terpenes.


V. ANALYTICAL CHEMISTRY

This branch of chemistry has for its province the determination of the
constituents of a chemical compound or of a mixture of compounds. Such a
determination is _qualitative_, the constituent being only detected or
proved to be present, or _quantitative_, in which the amount present is
ascertained. The methods of chemical analysis may be classified
according to the type of reaction: (1) _dry_ or _blowpipe analysis_,
which consists in an examination of the substance in the dry condition;
this includes such tests as ignition in a tube, ignition on charcoal in
the blowpipe flame, fusion with borax, microcosmic salt or fluxes, and
flame colorations (in quantitative work the dry methods are sometimes
termed "dry assaying"); (2) _wet analysis_, in which a solution of the
substance is treated with reagents which produce specific reactions when
certain elements or groups of elements are present. In quantitative
analysis the methods can be subdivided into: (a) _gravimetric_, in which
the constituent is precipitated either as a definite insoluble compound
by the addition of certain reagents, or electrolytically, by the passage
of an electric current; (b) _volumetric_, in which the volume of a
reagent of a known strength which produces a certain definite reaction
is measured; (c) _colorimetric_, in which the solution has a particular
tint, which can be compared with solutions of known strengths.

_Historical._--The germs of analytical chemistry are to be found in the
writings of the pharmacists and chemists of the iatrochemical period.
The importance of ascertaining the proximate composition of bodies was
clearly realized by Otto Tachenius; but the first systematic
investigator was Robert Boyle, to whom we owe the introduction of the
term _analysis_. Boyle recognized many reagents which gave precipitates
with certain solutions: he detected sulphuric and hydrochloric acids by
the white precipitates formed with calcium chloride and silver nitrate
respectively; ammonia by the white cloud formed with the vapours of
nitric or hydrochloric acids; and copper by the deep blue solution
formed by a solution of ammonia. Of great importance is his introduction
of vegetable juices (the so-called _indicators_, q.v.) to detect acids
and bases. During the phlogistic period, the detection of the
constituents of compounds was considerably developed. Of the principal
workers in this field we may notice Friedrich Hoffmann, Andreas
Sigismund Marggraf (who detected iron by its reaction with potassium
ferrocyanide, and potassium and sodium by their flame colorations), and
especially Carl Scheele and Torbern Olof Bergman. Scheele enriched the
knowledge of chemistry by an immense number of facts, but he did not
possess the spirit of working systematically as Bergman did. Bergman
laid the foundations of systematic qualitative analysis, and devised
methods by which the metals may be separated into groups according to
their behaviour with certain reagents. This subdivision, which is of
paramount importance in the analysis of minerals, was subsequently
developed by Wilhelm August Lampadius in his _Handbuch zur chemischen
Analyse der Mineralien_ (1801) and by John Friedrich A. Göttling in his
_Praktische Anleitung zur prüfenden und zurlegenden Chemie_ (1802).

The introduction of the blowpipe into dry qualitative analysis by Axel
Fredrik Cronstedt marks an important innovation. The rapidity of the
method, and the accurate results which it gave in the hands of a
practised experimenter, led to its systematization by Jöns Jakob
Berzelius and Johann Friedrich Ludwig Hausmann, and in more recent times
by K.F. Plattner, whose treatise _Die Probirkunst mit dem Löthrohr_ is a
standard work on the subject. Another type of dry reaction, namely, the
_flame coloration_, had been the subject of isolated notices, as, for
example, the violet flame of potassium and the orange flame of sodium
observed by Marggraf and Scheele, but a systematic account was wanting
until Cartmell took the subject up. His results (_Phil. Mag._ 16, p.
382) were afterwards perfected by Robert Wilhelm Bunsen and Gustav Merz.
Closely related to the flame-colorations, we have to notice the great
services rendered by the spectroscope to the detection of elements.
Rubidium, caesium, thallium, indium and gallium were first discovered by
means of this instrument; the study of the rare earths is greatly
facilitated, and the composition of the heavenly bodies alone
determinable by it.

Quantitative chemistry had been all but neglected before the time of
Lavoisier, for although a few chemists such as Tachenius, Bergman and
others had realized the advantages which would accrue from a knowledge
of the composition of bodies by weight, and had laid down the lines
upon which such determinations should proceed, the experimental
difficulties in making accurate observations were enormous, and little
progress could be made until the procedure was more accurately
determined. Martin Heinrich Klaproth showed the necessity for igniting
precipitates before weighing them, if they were not decomposed by this
process; and he worked largely with Louis Nicolas Vauquelin in
perfecting the analysis of minerals. K.F. Wenzel and J.B. Richter
contributed to the knowledge of the quantitative composition of salts.
Anton Laurent Lavoisier, however, must be considered as the first great
exponent of this branch of chemistry. He realized that the composition
by weight of chemical compounds was of the greatest moment if chemistry
were to advance. His fame rests upon his exposition of the principles
necessary to chemistry as a science, but of his contributions to
analytical inorganic chemistry little can be said. He applied himself
more particularly to the oxygen compounds, and determined with a fair
degree of accuracy the ratio of carbon to oxygen in carbon dioxide, but
his values for the ratio of hydrogen to oxygen in water, and of
phosphorus to oxygen in phosphoric acid, are only approximate; he
introduced no new methods either for the estimation or separation of the
metals. The next advance was made by Joseph Louis Proust, whose
investigations led to a clear grasp of the law of constant proportions.
The formulation of the atomic theory by John Dalton gave a fresh impetus
to the development of quantitative analysis; and the determination of
combining or equivalent weights by Berzelius led to the perfecting of
the methods of gravimetric analysis. Experimental conditions were
thoroughly worked out; the necessity of working with hot or cold
solutions was clearly emphasized; and the employment of small quantities
of substances instead of the large amounts recommended by Klaproth was
shown by him to give more consistent results.

Since the time of Berzelius many experimenters have entered the lists,
and introduced developments which we have not space to mention. We may,
however, notice Heinrich Rose[15] and Friedrich Wohler,[16] who, having
worked up the results of their teacher Berzelius, and combined them with
their own valuable observations, exerted great influence on the progress
of analytical chemistry by publishing works which contained admirable
accounts of the then known methods of analysis. To K.R. Fresenius, the
founder of the _Zeitschrift für analytische Chemie_ (1862), we are
particularly indebted for perfecting and systematizing the various
methods of analytical chemistry. By strengthening the older methods, and
devising new ones, he exerted an influence which can never be
overestimated. His text-books on the subject, of which the _Qualitative_
appeared in 1841, and the _Quantitative_ in 1846, have a world-wide
reputation, and have passed through several editions.

The quantitative precipitation of metals by the electric current,
although known to Michael Faraday, was not applied to analytical
chemistry until O. Wolcott Gibbs worked out the electrolytic separation
of copper in 1865. Since then the subject has been extensively studied,
more particularly by Alexander Classen, who has summarized the methods
and results in his _Quantitative Chemical Analysis by Electrolysis_
(1903). The ever-increasing importance of the electric current in
metallurgy and chemical manufactures is making this method of great
importance, and in some cases it has partially, if not wholly,
superseded the older methods.

Volumetric analysis, possessing as it does many advantages over the
gravimetric methods, has of late years been extensively developed. Gay
Lussac may be regarded as the founder of the method, although rough
applications had been previously made by F.A.H. Descroizilles and L.N.
Vauquelin. Chlorimetry (1824), alkalimetry (1828), and the volumetric
determination of silver and chlorine (1832) were worked out by Gay
Lussac; but although the advantages of the method were patent, it
received recognition very slowly. The application of potassium
permanganate to the estimation of iron by E. Margueritte in 1846, and
of iodine and sulphurous acid to the estimation of copper and many other
substances by Robert Wilhelm Bunsen, marks an epoch in the early history
of volumetric analysis. Since then it has been rapidly developed,
particularly by Karl Friedrich Mohr and J. Volhard, and these methods
rank side by side in value with the older and more tedious gravimetric
methods.

The detection of carbon and hydrogen in organic compounds by the
formation of carbon dioxide and water when they are burned was first
correctly understood by Lavoisier, and as he had determined the carbon
and hydrogen content of these two substances he was able to devise
methods by which carbon and hydrogen in organic compounds could be
estimated. In his earlier experiments he burned the substance in a known
volume of oxygen, and by measuring the residual gas determined the
carbon and hydrogen. For substances of a difficultly combustible nature
he adopted the method in common use to-day, viz. to mix the substance
with an oxidizing agent--mercuric oxide, lead dioxide, and afterwards
copper oxide--and absorb the carbon dioxide in potash solution. This
method has been improved, especially by Justus v. Liebig; and certain
others based on a different procedure have been suggested. The
estimation of nitrogen was first worked out in 1830 by Jean Baptiste
Dumas, and different processes have been proposed by Will and F.
Varrentrapp, J. Kjeldahl and others. Methods for the estimation of the
halogens and sulphur were worked out by L. Carius (see below, § _Organic
Analysis_).

Only a reference can be made in this summary to the many fields in which
analytical chemistry has been developed. Progress in forensic chemistry
was only possible after the reactions of poisons had been systematized;
a subject which has been worked out by many investigators, of whom we
notice K.R. Fresenius, J. and R. Otto, and J.S. Stas. Industrial
chemistry makes many claims upon the chemist, for it is necessary to
determine the purity of a product before it can be valued. This has led
to the estimation of sugar by means of the polarimeter, and of the
calorific power of fuels, and the valuation of ores and metals, of
coal-tar dyes, and almost all trade products.

The passing of the Food and Drug Acts (1875-1899) in England, and the
existence of similar adulteration acts in other countries, have
occasioned great progress in the analysis of foods, drugs, &c. For
further information on this branch of analytical chemistry, see
ADULTERATION.

There exists no branch of technical chemistry, hygiene or pharmacy from
which the analytical chemist can be spared, since it is only by a
continual development of his art that we can hope to be certain of the
purity of any preparation. In England this branch of chemistry is
especially cared for by the Institute of Chemistry, which, since its
foundation in 1877, has done much for the training of analytical
chemists.

In the preceding sketch we have given a necessarily brief account of the
historical development of analytical chemistry in its main branches. We
shall now treat the different methods in more detail. It must be
mentioned here that the reactions of any particular substance are given
under its own heading, and in this article we shall only collate the
various operations and outline the general procedure. The limits of
space prevent any systematic account of the separation of the rare
metals, the alkaloids, and other classes of organic compounds, but
sources where these matters may be found are given in the list of
references.


_Qualitative Inorganic Analysis._

  Dry methods.

The dry examination of a substance comprises several operations, which
may yield definite results if no disturbing element is present; but it
is imperative that any inference should be confirmed by other methods.

1. Heat the substance in a hard glass tube. Note whether any moisture
condenses on the cooler parts of the tube, a gas is evolved, a sublimate
formed, or the substance changes colour.

  Moisture is evolved from substances containing water of
  crystallization or decomposed hydrates. If it possesses an alkaline or
  acid reaction, it must be tested in the first case for ammonia, and in
  the second case for a volatile acid, such as sulphuric, nitric,
  hydrochloric, &c.

  Any evolved gas must be examined. Oxygen, recognized by its power of
  igniting a glowing splinter, results from the decomposition of oxides
  of the noble metals, peroxides, chlorates, nitrates and other highly
  oxygenized salts. Sulphur dioxide, recognized by its smell and acid
  reaction, results from the ignition of certain sulphites, sulphates,
  or a mixture of a sulphate with a sulphide. Nitrogen oxides,
  recognized by their odour and brown-red colour, result from the
  decomposition of nitrates. Carbon dioxide, recognized by turning
  lime-water milky, indicates decomposable carbonates or oxalates.
  Chlorine, bromine, and iodine, each recognizable by its colour and
  odour, result from decomposable haloids; iodine forms also a black
  sublimate. Cyanogen and hydrocyanic acid, recognizable by their odour,
  indicate decomposable cyanides. Sulphuretted hydrogen, recognized by
  its odour, results from sulphides containing water, and
  hydrosulphides. Ammonia, recognizable by its odour and alkaline
  reaction, indicates ammoniacal salts or cyanides containing water.

  A sublimate may be formed of: sulphur--reddish-brown drops, cooling to
  a yellow to brown solid, from sulphides or mixtures; iodine--violet
  vapour, black sublimate, from iodides, iodic acid, or mixtures;
  mercury and its compounds--metallic mercury forms minute globules,
  mercuric sulphide is black and becomes red on rubbing, mercuric
  chloride fuses before subliming, mercurous chloride does not fuse,
  mercuric iodide gives a yellow sublimate; arsenic and its
  compounds--metallic arsenic gives a grey mirror, arsenious oxide forms
  white shining crystals, arsenic sulphides give reddish-yellow
  sublimates which turn yellow on cooling; antimony oxide fuses and
  gives a yellow acicular sublimate; lead chloride forms a white
  sublimate after long and intense heating.

  If the substance does not melt but changes colour, we may have
  present: zinc oxide--from white to yellow, becoming white on cooling;
  stannic oxide--white to yellowish brown, dirty white on cooling; lead
  oxide--from white or yellowish-red to brownish-red, yellow on cooling;
  bismuth oxide--from white or pale yellow to orange-yellow or
  reddish-brown, pale yellow on cooling; manganese oxide--from white or
  yellowish white to dark brown, remaining dark brown on cooling (if it
  changes on cooling to a bright reddish-brown, it indicates cadmium
  oxide); copper oxide--from bright blue or green to black; ferrous
  oxide--from greyish-white to black; ferric oxide--from brownish-red to
  black, brownish-red on cooling; potassium chromate--yellow to dark
  orange, fusing at a red heat.

2. Heat the substance on a piece of charcoal in the reducing flame of
the blowpipe.

  ([alpha]) The substance may fuse and be absorbed by the charcoal; this
  indicates more particularly the alkaline metals.

  ([beta]) An infusible white residue may be obtained, which may denote
  barium, strontium, calcium, magnesium, aluminium or zinc. The first
  three give characteristic flame colorations (see below); the last
  three, when moistened with cobalt nitrate and re-ignited, give
  coloured masses; aluminium (or silica) gives a brilliant blue; zinc
  gives a green; whilst magnesium phosphates or arsenate (and to a less
  degree the phosphates of the alkaline earths) give a violet mass.

  A metallic globule with or without an incrustation may be obtained.
  Gold and copper salts give a metallic bead without an incrustation. If
  the incrustation be white and readily volatile, arsenic is present, if
  more difficultly volatile and beads are present, antimony; zinc gives
  an incrustation yellow whilst hot, white on cooling, and volatilized
  with difficulty; tin gives a pale yellow incrustation, which becomes
  white on cooling, and does not volatilize in either the reducing or
  oxidizing flames; lead gives a lemon-yellow incrustation turning
  sulphur-yellow on cooling, together with metallic malleable beads;
  bismuth gives metallic globules and a dark orange-yellow incrustation,
  which becomes lemon-yellow on cooling; cadmium gives a reddish-brown
  incrustation, which is removed without leaving a gleam by heating in
  the reducing flame; silver gives white metallic globules and a
  dark-red incrustation.

3. Heat the substance with a bead of microcosmic salt or borax on a
platinum wire in the oxidizing flame.

  ([alpha]) The substance dissolves readily and in quantity, forming a
  bead which is clear when hot. If the bead is coloured we may have
  present: cobalt, blue to violet; copper, green, blue on cooling; in
  the reducing flame, red when cold; chromium, green, unaltered in the
  reducing flame; iron, brownish-red, light-yellow or colourless on
  cooling; in the reducing flame, red while hot, yellow on cooling,
  greenish when cold; nickel, reddish to brownish-red, yellow to
  reddish-yellow or colourless on cooling, unaltered in the reducing
  flame; bismuth, yellowish-brown, light-yellow or colourless on
  cooling; in the reducing flame, almost colourless, blackish-grey when
  cold; silver, light yellowish to opal, somewhat opaque when cold;
  whitish-grey in the reducing flame; manganese, amethyst red,
  colourless in the reducing flame. If the hot bead is colourless and
  remains clear on cooling, we may suspect the presence of antimony,
  aluminium, zinc, cadmium, lead, calcium and magnesium. When present in
  sufficient quantity the five last-named give enamel-white beads; lead
  oxide in excess gives a yellowish bead. If the hot colourless bead
  becomes enamel-white on cooling even when minute quantities of the
  substances are employed, we may infer the presence of barium or
  strontium.

  ([beta]) The substance dissolves slowly and in small quantity, and
  forms a colourless bead which remains so on cooling. Either silica or
  tin may be present. If silica be present, it gives the iron bead when
  heated with a little ferric oxide; if tin is present there is no
  change. Certain substances, such as the precious metals, are quite
  insoluble in the bead, but float about in it.

4. Hold a small portion of the substance moistened with hydrochloric
acid on a clean platinum wire in the fusion zone of the Bunsen burner,
and note any colour imparted to the flame.

  Potassium gives a blue-violet flame which may be masked by the
  colorations due to sodium, calcium and other elements. By viewing the
  flame through an indigo prism it appears sky-blue, violet and
  ultimately crimson, as the thickness of the prism is increased. Other
  elements do not interfere with this method. Sodium gives an intense
  and persistent yellow flame; lithium gives a carmine coloration, and
  may be identified in the presence of sodium by viewing through a
  cobalt glass or indigo prism; from potassium it may be distinguished
  by its redder colour; barium gives a yellowish-green flame, which
  appears bluish-green when viewed through green glass; strontium gives
  a crimson flame which appears purple or rose when viewed through blue
  glass; calcium gives an orange-red colour which appears finch-green
  through green glass; indium gives a characteristic bluish-violet
  flame; copper gives an intense emerald-green coloration.

5. _Film Reactions._--These reactions are practised in the following
manner:--A thread of asbestos is moistened and then dipped in the
substance to be tested; it is then placed in the luminous point of the
Bunsen flame, and a small porcelain basin containing cold water placed
immediately over the asbestos. The formation of a film is noted. The
operation is repeated with the thread in the oxidizing flame.

  Any film formed in the first case is metallic, in the second it is the
  oxide. The metallic film is tested with 20% nitric acid and with
  bleaching-powder solution. Arsenic is insoluble in the acid, but
  immediately dissolves in the bleaching-powder. The black films of
  antimony and bismuth and the grey mottled film of mercury are slowly
  soluble in the acid, and untouched by bleaching-powder. The black
  films of tin, lead and cadmium dissolve at once in the acid, the lead
  film being also soluble in bleaching-powder. The oxide films of
  antimony, arsenic, tin and bismuth are white, that of bismuth slightly
  yellowish; lead yields a very pale yellow film, and cadmium a brown
  one; mercury yields no oxide film. The oxide films (the metallic one
  in the case of mercury) are tested with hydriodic acid, and with
  ammonium sulphide, and from the changes produced the film can be
  determined (see F.M. Perkin, _Qualitative Chemical Analysis_, 1905).


  Wet methods.

Having completed the dry analysis we may now pass on to the _wet_ and
more accurate investigation. It is first necessary to get the substance
into solution. Small portions should be successively tested with water,
dilute hydrochloric acid, dilute nitric acid, strong hydrochloric acid,
and a mixture of hydrochloric and nitric acids, first in the cold and
then with warming. Certain substances are insoluble in all these
reagents, and other methods, such as the fusion with sodium carbonate
and potassium nitrate, and subsequent treatment with an acid, must be
employed. Some of these insoluble compounds can be detected by their
colour and particular reactions. For further information on this
subject, we refer the readers to Fresenius's _Qualitative Analysis_.

  The procedure for the detection of metals in solution consists of
  first separating them into groups and then examining each group
  separately. For this purpose the cold solution is treated with
  hydrochloric acid, which precipitates lead, silver and mercurous salts
  as chlorides. The solution is filtered and treated with an excess of
  sulphuretted hydrogen, either in solution or by passing in the gas;
  this precipitates mercury (mercuric), any lead left over from the
  first group, copper, bismuth, cadmium, arsenic, antimony and tin as
  sulphides. The solution is filtered off, boiled till free of
  sulphuretted hydrogen, and ammonium chloride and ammonia added. If
  phosphoric acid is absent, aluminium, chromium and ferric hydrates are
  precipitated. If, however, phosphoric acid is present in the original
  substance, we may here obtain a precipitate of the phosphates of the
  remaining metals, together with aluminium, chromium and ferric
  hydrates. In this case, the precipitate is dissolved in as little as
  possible hydrochloric acid and boiled with ammonium acetate, acetic
  acid and ferric chloride. The phosphates of aluminium, chromium and
  iron are precipitated, and the solution contains the same metals as if
  phosphoric acid had been absent. To the filtrate from the aluminium,
  iron and chromium precipitate, ammonia and ammonium sulphide are
  added; the precipitate may contain nickel, cobalt, zinc and manganese
  sulphides. Ammonium carbonate is added to the filtrate; this
  precipitates calcium, strontium and barium. The solution contains
  magnesium, sodium and potassium, which are separately distinguished by
  the methods given under their own headings.

  We now proceed with the examination of the various group precipitates.
  The white precipitate formed by cold hydrochloric acid is boiled with
  water, and the solution filtered while hot. Any lead chloride
  dissolves, and may be identified by the yellow precipitate formed with
  potassium chromate. To the residue add ammonia, shake, then filter.
  Silver chloride goes into solution, and may be precipitated by dilute
  nitric acid. The residue, which is black in colour, consists of
  mercuroso-ammonium chloride, in which mercury can be confirmed by its
  ordinary tests.

  The precipitate formed by sulphuretted hydrogen may contain the black
  mercuric, lead, and copper sulphides, dark-brown bismuth sulphide,
  yellow cadmium and arsenious sulphides, orange-red antimony sulphide,
  brown stannous sulphide, dull-yellow stannic sulphide, and whitish
  sulphur, the last resulting from the oxidation of sulphuretted
  hydrogen by ferric salts, chromates, &c. Warming with ammonium
  sulphide dissolves out the arsenic, antimony and tin salts, which are
  reprecipitated by the addition of hydrochloric acid to the ammonium
  sulphide solution. The precipitate is shaken with ammonium carbonate,
  which dissolves the arsenic. Filter and confirm arsenic in the
  solution by its particular tests. Dissolve the residue in hydrochloric
  acid and test separately for antimony and tin. The residue from the
  ammonium sulphide solution is warmed with dilute nitric acid. Any
  residue consists of black mercuric sulphide (and possibly white lead
  sulphate), in which mercury is confirmed by its usual tests. The
  solution is evaporated with a little sulphuric acid and well cooled.
  The white precipitate consists of lead sulphate. To the filtrate add
  ammonia in excess; a white precipitate indicates bismuth; if the
  solution be blue, copper is present. Filter from the bismuth hydrate,
  and if copper is present, add potassium cyanide till the colour is
  destroyed, then pass sulphuretted hydrogen, and cadmium is
  precipitated as the yellow sulphide. If copper is absent, then
  sulphuretted hydrogen can be passed directly into the solution.

  The next group precipitate may contain the white gelatinous aluminium
  hydroxide, the greenish chromium hydroxide, reddish ferric hydroxide,
  and possibly zinc and manganese hydroxides. Treatment with casutic
  soda dissolves out aluminium hydroxide, which is reprecipitated by the
  addition of ammonium chloride. The remaining metals are tested for
  separately.

  The next group may contain black nickel and cobalt sulphides,
  flesh-coloured manganese sulphide, and white zinc sulphide. The last
  two are dissolved out by cold, very dilute hydrochloric acid, and the
  residue is tested for nickel and cobalt. The solution is boiled till
  free from sulphuretted hydrogen and treated with excess of sodium
  hydrate. A white precipitate rapidly turning brown indicates
  manganese. The solution with ammonium sulphide gives a white
  precipitate of zinc sulphide.

  The next group may contain the white calcium, barium and strontium
  carbonates. The flame coloration (see above) may give information as
  to which elements are present. The carbonates are dissolved in
  hydrochloric acid, and calcium sulphate solution is added to a portion
  of the solution. An immediate precipitate indicates barium; a
  precipitate on standing indicates strontium. If barium is present, the
  solution of the carbonates in hydrochloric acid is evaporated and
  digested with strong alcohol for some time; barium chloride, which is
  nearly insoluble in alcohol, is thus separated, the remainder being
  precipitated by a few drops of hydrofluosilicic acid, and may be
  confirmed by the ordinary tests. The solution free from barium is
  treated with ammonia and ammonium sulphate, which precipitates
  strontium, and the calcium in the solution may be identified by the
  white precipitate with ammonium oxalate.

Having determined the bases, it remains to determine the acid radicals.
There is no general procedure for these operations, and it is customary
to test for the acids separately by special tests; these are given in
the articles on the various acids. A knowledge of the solubility of
salts considerably reduces the number of acids likely to be present, and
affords evidence of great value to the analyst (see A.M. Comey,
_Dictionary of Chemical Solubilities_.) In the above account we have
indicated the procedure adopted in the analysis of a complex mixture of
salts. It is unnecessary here to dwell on the precautions which can only
be conveniently acquired by experience; a sound appreciation of
analytical methods is only possible after the reactions and characters
of individual substances have been studied, and we therefore refer the
reader to the articles on the particular elements and compounds for more
information on this subject.

_Quantitative Inorganic Analysis_.

Quantitative methods are divided into four groups, which we now pass on
to consider in the following sequence: ([alpha]) gravimetric, ([beta])
volumetric, ([gamma]) electrolytic, ([delta]) colorimetric.

([alpha]) _Gravimetric._--This method is made up of four operations: (1)
a weighed quantity of the substance is dissolved in a suitable solvent;
(2) a particular reagent is added which precipitates the substance it is
desired to estimate; (3) the precipitate is filtered, washed and dried;
(4) the filter paper containing the precipitate is weighed either as a
_tared_ filter, or incinerated and ignited either in air or in any other
gas, and then weighed.

  (1) Accurate weighing is all-important: for details of the various
  appliances and methods see WEIGHING MACHINES. (2) No general
  directions can be given as to the method of precipitation. Sometimes
  it is necessary to allow the solution to stand for a considerable time
  either in the warm or cold or in the light or dark; to work with cold
  solutions and then boil; or to use boiling solutions of both the
  substance and reagent. Details will be found in the articles on
  particular metals. (3) The operation of filtration and washing is very
  important. If the substance to be weighed changes in composition on
  strong heating, it is necessary to employ a tared filter, i.e. a
  filter paper which has been previously heated to the temperature at
  which the substance is to be dried until its weight is constant. If
  the precipitate settles readily, the supernatant liquor may be
  decanted through the filter paper, more water added to the precipitate
  and again decanted. By this means most of the washing, i.e.freeing
  from the other substances in the solution, can be accomplished in the
  precipitating vessel. If, however, the precipitate refuses to settle,
  it is directly transferred to the filter paper, the last traces being
  removed by washing and rubbing the sides of the vessel with a piece of
  rubber, and the liquid is allowed to drain through. It is washed by
  ejecting a jet of water, ammonia or other prescribed liquid on to the
  side of the filter paper until the paper is nearly full. It can be
  shown that a more efficient washing results from alternately filling
  and emptying the funnel than by endeavouring to keep the funnel full.
  The washing is continued until the filtrate is free from salts or
  acids. (4) After washing, the funnel containing the filter paper is
  transferred to a drying oven. In the case of a tared filter it is
  weighed repeatedly until the weight suffers no change; then knowing
  the weight of the filter paper, the weight of the precipitate is
  obtained by subtraction. If the precipitate may be ignited, it is
  transferred to a clean, weighed and recently ignited crucible, and the
  filter paper is burned _separately_ on the lid, the ash transferred to
  the crucible, and the whole ignited. After ignition, it is allowed to
  cool in a desiccator and then weighed. Knowing the weight of the
  crucible and of the ash of the filter paper, the weight of the
  precipitate is determined. The calculation of the percentage of the
  particular constituent is simple. We know the amount present in the
  precipitate, and since the same amount is present in the quantity of
  substance experimented with, we have only to work out a sum in
  proportion.

([beta]) _Volumetric._--This method is made up of three operations:--(1)
preparation of a _standard_ solution; (2) preparation of a solution of
the substance; (3) _titration_, or the determination of what volume of
the standard solution will occasion a known and definite reaction with a
known volume of the test solution.

  (1) In general analytical work the standard solution contains the
  equivalent weight of the substance in grammes dissolved in a litre of
  water. Such a solution is known as _normal_. Thus a normal solution of
  sodium carbonate contains 53 grammes per litre, of sodium hydrate 40
  grammes, of hydrochloric acid 36.5 grammes, and so on. By taking
  1/10th or 1/100th of these quantities, _decinormal_ or _centinormal_
  solutions are obtained. We see therefore that 1 cubic centimetre of a
  normal sodium carbonate solution will exactly neutralize 0.049 gramme
  of sulphuric acid, 0.0365 gramme of hydrochloric acid (i.e. the
  equivalent quantities), and similarly for decinormal and centinormal
  solutions. Unfortunately, the term normal is sometimes given to
  solutions which are strictly decinormal; for example, iodine, sodium
  thiosulphate, &c. In technical analysis, where a solution is used for
  one process only, it may be prepared so that 1 cc. is equal to .01
  gramme of the substance to be estimated. This saves a certain amount
  of arithmetic, but when the solution is applied in another
  determination additional calculations are necessary. Standard
  solutions are prepared by weighing out the exact amount of the pure
  substance and dissolving it in water, or by forming a solution of
  approximate normality, determining its exact strength by gravimetric
  or other means, and then correcting it for any divergence. This may be
  exemplified in the case of alkalimetry. Pure sodium carbonate is
  prepared by igniting the bicarbonate, and exactly 53 grammes are
  dissolved in water, forming a strictly normal solution. An approximate
  normal sulphuric acid is prepared from 30 ccs. of the pure acid (1.84
  specific gravity) diluted to 1 litre. The solutions are titrated (see
  below) and the acid solution diluted until equal volumes are exactly
  equivalent. A standard sodium hydrate solution can be prepared by
  dissolving 42 grammes of sodium hydrate, making up to a litre, and
  diluting until one cubic centimetre is exactly equivalent to one cubic
  centimetre of the sulphuric acid. Similarly, normal solutions of
  hydrochloric and nitric acids can be prepared. Where a solution is
  likely to change in composition on keeping, such as potassium
  permanganate, iodine, sodium hydrate, &c., it is necessary to check
  or re-standardize it periodically.

  (2) The preparation of the solution of the substance consists in
  dissolving an accurately determined weight, and making up the volume
  in a graduated cylinder or flask to a known volume.

  (3) The titration is conducted by running the standard solution from a
  burette into a known volume of the test solution, which is usually
  transferred from the stock-bottle to a beaker or basin by means of a
  pipette. Various artifices are employed to denote the end of the
  reaction. These may be divided into two groups: (1) those in which a
  change in appearance of the reacting mixture occurs; (2) those in
  which it is necessary to use an indicator which, by its change in
  appearance, shows that an excess of one reagent is present. In the
  first group, we have to notice the titration of a cyanide with silver
  nitrate, when a milkiness shows how far the reaction has gone; the
  titration of iron with permanganate, when the faint pink colour shows
  that all the iron is oxidized. In the second group, we may notice the
  application of litmus, methyl orange or phenolphthalein in
  alkalimetry, when the acid or alkaline character of the solution
  commands the colour which it exhibits; starch paste, which forms a
  blue compound with free iodine in iodometry; potassium chromate, which
  forms red silver chromate after all the hydrochloric acid is
  precipitated in solutions of chlorides; and in the estimation of
  ferric compounds by potassium bichromate, the indicator, potassium
  ferricyanide, is placed in drops on a porcelain plate, and the end of
  the reaction is shown by the absence of a blue coloration when a drop
  of the test solution is brought into contact with it.

([gamma]) _Electrolytic._--This method consists in decomposing a
solution of a salt of the metal by the electric current and weighing the
metal deposited at the cathode.

  It is only by paying great attention to the current density that good
  results are obtained, since metals other than that sought for may be
  deposited. In acid copper solutions, mercury is deposited before the
  copper with which it subsequently amalgamates; silver is thrown down
  simultaneously; bismuth appears towards the end; and after all the
  copper has been precipitated, arsenic and antimony may be deposited.
  Lead and manganese are partially separated as peroxides, but the
  remaining metals are not deposited from acid solutions. It is
  therefore necessary that the solution should be free from metals which
  may vitiate the results, or special precautions taken by which the
  impurities are rendered harmless. In such cases the simplicity of
  manipulation and the high degree of accuracy of the method have made
  it especially valuable. The electrolysis is generally conducted with
  platinum electrodes, of which the cathode takes the form of a piece of
  foil bent into a cylindrical form, the necessary current being
  generated by one or more Daniell cells.

([delta]) _Colorimetric._--This method is adopted when it is necessary
to determine minute traces (as in the liquid obtained in the
electrolytic separation of copper) of substances which afford
well-defined colour reactions.

  The general procedure is to make a series of standard solutions
  containing definite quantities of the substance which it is desired to
  estimate; such a series will exhibit tints which deepen as the
  quantity of the substance is increased. A known weight of the test
  substance is dissolved and a portion of the solution is placed in a
  tube similar to those containing the standard solutions. The
  colour-producing reagent is added and the tints compared. In the case
  of copper, the colour reactions with potassium ferrocyanide or ammonia
  are usually employed; traces of ammonia are estimated with _Nessler's
  reagent_; sulphur in iron and steel is determined by the tint assumed
  by a silver-copper plate suspended in the gases liberated when the
  metal is dissolved in sulphuric acid (Eggertz's test) (see W. Crookes,
  _Select Methods in Analytical Chemistry_).

_Organic Analysis._

The elements which play important parts in organic compounds are carbon,
hydrogen, nitrogen, chlorine, bromine, iodine, sulphur, phosphorus and
oxygen. We shall here consider the qualitative and quantitative
determination of these elements.

  _Qualitative._--Carbon is detected by the formation of carbon dioxide,
  which turns lime-water milky, and hydrogen by the formation of water,
  which condenses on the tube, when the substance is heated with copper
  oxide. Nitrogen may be detected by the evolution of ammonia when the
  substance is heated with soda-lime. A more delicate method is that due
  to J. L. Lassaigne and improved by O. Jacobsen and C. Graebe. The
  substance is heated with metallic sodium or potassium (in excess if
  sulphur be present) to redness, the residue treated with water,
  filtered, and ferrous sulphate, ferric chloride and hydrochloric acid
  added. A blue coloration indicates nitrogen, and is due to the
  formation of potassium (or sodium) cyanide during the fusion, and
  subsequent interaction with the iron salts. The halogens may be
  sometimes detected by fusing with lime, and testing the solution for a
  bromide, chloride and iodide in the usual way. F. Beilstein determines
  their presence by heating the substance with pure copper oxide on a
  platinum wire in the Bunsen flame; a green coloration is observed if
  halogens be present. Sulphur is detected by heating the substance with
  sodium, dissolving the product in water, and adding sodium
  nitroprusside; a bluish-violet coloration indicates sulphur (H. Vohl).
  Or we may use J. Horbaczewski's method, which consists in boiling the
  substance with strong potash, saturating the cold solution with
  chlorine, adding hydrochloric acid, and boiling till no more chlorine
  is liberated, and then testing for sulphuric acid with barium
  chloride. Phosphorus is obtained as a soluble phosphate (which can be
  examined in the usual way) by lixiviating the product obtained when
  the substance is ignited with potassium nitrate and carbonate.


    Carbon and hydrogen.

  _Quantitative._--Carbon and hydrogen are generally estimated by the
  _combustion_ process, which consists in oxidizing the substance and
  absorbing the products of combustion in suitable apparatus. The
  oxidizing agent in commonest use is copper oxide, which must be
  freshly ignited before use on account of its hygroscopic nature. Lead
  chromate is sometimes used, and many other substances, such as
  platinum, manganese dioxide, &c., have been suggested. The procedure
  for a combustion is as follows:--

  [Illustration: FIG. 1.]

  [Illustration: FIG. 2.]

  [Illustration: FIG. 3.]

  [Illustration: FIG. 4.]


  A hard glass tube slightly longer than the furnace and 12 to 15 mm. in
  diameter is thoroughly cleansed and packed as shown in fig. 1. The
  space a must allow for the inclusion of a copper spiral if the
  substance contains nitrogen, and a silver spiral if halogens be
  present, for otherwise nitrogen oxides and the halogens may be
  condensed in the absorption apparatus; b contains copper oxide; c is a
  space for the insertion of a porcelain or platinum boat containing a
  weighed quantity of the substance; d is a copper spiral. The end d is
  connected to an air or oxygen supply with an intermediate drying
  apparatus. The other end is connected with the absorption vessels,
  which consist of a tube (e) containing calcium chloride, and a set of
  bulbs (f) containing potash solution. Various forms of potash bulbs
  are employed; fig. 2 is Liebig's, fig. 3 Mohr's or Geissler's, fig. 4
  is a more recent form, of which special variations have been made by
  Anderson, Gomberg, Delisle and others. After having previously roasted
  the tube and copper oxide, and reduced the copper spiral a, the
  weighed calcium chloride tube and potash bulbs are put in position,
  the boat containing the substance is inserted (in the case of a
  difficultly combustible substance it is desirable to mix it with
  cupric oxide or lead chromate), the copper spiral (d) replaced, and
  the air and oxygen supply connected up. The apparatus is then tested
  for leaks. If all the connexions are sound, the copper oxide is
  gradually heated from the end a, the gas-jets under the spiral d are
  lighted, and a slow current of oxygen is passed through the tube. The
  success of the operation depends upon the slow burning of the
  substance. Towards the end the heat and the oxygen supply are
  increased. When there is no more absorption in the potash bulbs, the
  oxygen supply is cut off and air passed through. Having replaced the
  oxygen in the absorption vessels by air, they are disconnected and
  weighed, after having cooled down to the temperature of the room. The
  increase in weight of the calcium chloride tube gives the weight of
  water formed, and of the potash bulbs the carbon dioxide.

  Liquids are amenable to the same treatment, but especial care must be
  taken so that they volatilize slowly. Difficultly volatile liquids may
  be weighed directly into the boat; volatile liquids are weighed in
  thin hermetically sealed bulbs, the necks of which are broken just
  before they are placed in the combustion tube.

  The length of time and other disadvantages attending the combustion
  method have caused investigators to devise other processes. In 1855 C.
  Brunner described a method for oxidizing the carbon to carbon dioxide,
  which could be estimated by the usual methods, by heating the
  substance with potassium bichromate and sulphuric acid. This process
  has been considerably developed by J. Messinger, and we may hope that
  with subsequent improvements it may be adapted to all classes of
  organic compounds. The oxidation, which is effected by chromic acid
  and sulphuric acid, is conducted in a flask provided with a funnel and
  escape tube, and the carbon dioxide formed is swept by a current of
  dry air, previously freed from carbon dioxide, through a drying tube
  to a set of potash bulbs and a tube containing soda-lime; if halogens
  are present, a small wash bottle containing potassium iodide, and a U
  tube containing glass wool moistened with silver nitrate on one side
  and strong sulphuric acid on the other, must be inserted between the
  flask and the drying tube. The increase in weight of the potash bulbs
  and soda-lime tube gives the weight of carbon dioxide evolved. C.F.
  Cross and E.J. Bevan collected the carbon dioxide obtained in this way
  over mercury. They also showed that carbon monoxide was given off
  towards the end of the reaction, and oxygen was not evolved unless the
  temperature exceeded 100°.

  Methods depending upon oxidation in the presence of a contact
  substance have come into favour during recent years. In that of M.
  Dennstedt, which was first proposed in 1902, the substance is
  vaporized in a tube containing at one end platinum foil, platinized
  quartz, or platinized asbestos. The platinum is maintained at a bright
  red heat, either by a gas flame or by an electric furnace, and the
  vapour is passed over it by leading in a current of oxygen. If
  nitrogen be present, a boat containing dry lead peroxide and heated to
  320° is inserted, the oxide decomposing any nitrogen peroxide which
  may be formed. The same absorbent quantitatively takes up any halogen
  and sulphur which may be present. The process is therefore adapted to
  the simultaneous estimation of carbon, hydrogen, the halogens and
  sulphur.


    Nitrogen.

  Nitrogen is estimated by (1) Dumas' method, which consists in heating
  the substance with copper oxide and measuring the volume of nitrogen
  liberated; (2) by Will and Varrentrapp's method, in which the
  substance is heated with soda-lime, and the ammonia evolved is
  absorbed in hydrochloric acid, and thence precipitated as ammonium
  chlorplatinate or estimated volumetrically; or (3) by Kjeldahl's
  method, in which the substance is dissolved in concentrated sulphuric
  acid, potassium permanganate added, the liquid diluted and boiled with
  caustic soda, and the evolved ammonia absorbed in hydrochloric acid
  and estimated as in Will and Varrentrapp's method.

  [Illustration: FIG. 5.]

  _Dumas' Method._--In this method the operation is carried out in a
  hard glass tube sealed at one end and packed as shown in fig. 5. The
  magnesite (a) serves for the generation of carbon dioxide which clears
  the tube of air before the compound (mixed with fine copper oxide (b))
  is burned, and afterwards sweeps the liberated nitrogen into the
  receiving vessel (e), which contains a strong potash solution; c is
  coarse copper oxide; and d a reduced copper gauze spiral, heated in
  order to decompose any nitrogen oxides. Ulrich Kreusler generates the
  carbon dioxide in a separate apparatus, and in this case the tube is
  drawn out to a capillary at the end (a). This artifice is specially
  valuable when the substance decomposes or volatilizes in a warm
  current of carbon dioxide. Various forms of the absorbing apparatus
  (e) have been discussed by M. Ilinski (_Ber._ 17, p. 1347), who has
  also suggested the use of manganese carbonate instead of magnesite,
  since the change of colour enables one to follow the decomposition.
  Substances which burn with difficulty may be mixed with mercuric oxide
  in addition to copper oxide.

  _Will and Varrentrapp's Method._--This method, as originally proposed,
  is not in common use, but has been superseded by Kjeldahl's method,
  since the nitrogen generally comes out too low. It is susceptible of
  wider application by mixing reducing agents with the soda-lime: thus
  Goldberg (_Ber._ 16, p. 2546) uses a mixture of soda-lime, stannous
  chloride and sulphur for nitro- and azo-compounds, and C. Arnold
  (_Ber._ 18, p. 806) a mixture containing sodium hyposulphite and
  sodium formate for nitrates.

  _Kjeldahl's Method._--This method rapidly came into favour on account
  of its simplicity, both of operation and apparatus. Various substances
  other than potassium permanganate have been suggested for facilitating
  the operation; J.W. Gunning (_Z. anal. Chem._, 1889, p. 189) uses
  potassium sulphate; Lassar-Cohn uses mercuric oxide. The applicability
  of the process has been examined by F.W. Dafert (_Z. anal. Chem._,
  1888, p. 224), who has divided nitrogenous bodies into two classes
  with respect to it. The first class includes those substances which
  require no preliminary treatment, and comprises the amides and
  ammonium compounds, pyridines, quinolines, alkaloids, albumens and
  related bodies; the second class requires preliminary treatment and
  comprises, with few exceptions, the nitro-, nitroso-, azo-, diazo- and
  amidoazo-compounds, hydrazines, derivatives of nitric and nitrous
  acids, and probably cyanogen compounds. Other improvements have been
  suggested by Dyer (_J.C.S. Trans._ 67, p. 811). For an experimental
  comparison of the accuracy of the Dumas, Will-Varrentrapp and Kjeldahl
  processes see L. L'Hôte, _C.R._ 1889, p. 817. Debordeaux (_C.R._ 1904,
  p. 905) has obtained good results by distilling the substance with a
  mixture of potassium thiosulphate and sulphide.


    Halogens, sulphur, phosphorus.

  The halogens may be estimated by ignition with quicklime, or by
  heating with nitric acid and silver nitrate in a sealed tube. In the
  first method the substance, mixed with quicklime free from chlorine,
  is heated in a tube closed at one end in a combustion furnace. The
  product is dissolved in water, and the calcium haloid estimated in the
  usual way. The same decomposition may be effected by igniting with
  iron, ferric oxide and sodium carbonate (E. Kopp, _Ber._ 10, p. 290);
  the operation is easier if the lime be mixed with sodium carbonate, or
  a mixture of sodium carbonate and potassium nitrate be used. With
  iodine compounds, iodic acid is likely to be formed, and hence the
  solution must be reduced with sulphurous acid before precipitation
  with silver nitrate. C. Zulkowsky (_Ber._ 18, R. 648) burns the
  substance in oxygen, conducts the gases over platinized sand, and
  collects the products in suitable receivers. The oxidation with nitric
  acid in sealed tubes at a temperature of 150° to 200° for aliphatic
  compounds, and 250° to 260° for aromatic compounds, is in common use,
  for both the sulphur and phosphorus can be estimated, the former being
  oxidized to sulphuric acid and the latter to phosphoric acid. This
  method was due to L. Carius (_Ann._ 136, p. 129). R. Klason (_Ber._
  19, p. 1910) determines sulphur and the halogens by oxidizing the
  substance in a current of oxygen and nitrous fumes, conducting the
  vapours over platinum foil, and absorbing the vapours in suitable
  receivers. Sulphur and phosphorus can sometimes be estimated by
  Messinger's method, in which the oxidation is effected by potassium
  permanganate and caustic alkali, or by potassium bichromate and
  hydrochloric acid. A comparison of the various methods for estimating
  sulphur has been given by O. Hammarsten (_Zeit. physiolog. Chem._ 9,
  p. 273), and by Höland (_Chemiker Zeitung_, 1893, p. 991). H.H.
  Pringsheim (_Ber._ 38, p. 1434) has devised a method in which the
  oxidation is effected by sodium peroxide; the halogens, phosphorus and
  sulphur can be determined by one operation.


VI. PHYSICAL CHEMISTRY

We have seen how chemistry may be regarded as having for its province
the investigation of the composition of matter, and the changes in
composition which matter or energy may effect on matter, while physics
is concerned with the general properties of matter. A physicist,
however, does more than merely quantitatively determine specific
properties of matter; he endeavours to establish mathematical laws which
co-ordinate his observations, and in many cases the equations expressing
such laws contain functions or terms which pertain solely to the
chemical composition of matter. One example will suffice here. The
limiting law expressing the behaviour of gases under varying temperature
and pressure assumes the form pv = RT; so stated, this law is
independent of chemical composition and may be regarded as a true
physical law, just as much as the law of universal gravitation is a true
law of physics. But this relation is not rigorously true; in fact, it
does not accurately express the behaviour of any gas. A more accurate
expression (see CONDENSATION OF GASES and MOLECULE) is (p + a/v²)(v - b)
= RT, in which a and b are quantities which depend on the composition of
the gas, and vary from one gas to another.

It may be surmised that the quantitative measures of most physical
properties will be found to be connected with the chemical nature of
substances. In the investigation of these relations the physicist and
chemist meet on common ground; this union has been attended by fruitful
and far-reaching results, and the correlation of physical properties and
chemical composition is one of the most important ramifications of
physical chemistry. This branch receives treatment below. Of
considerable importance, also, are the properties of solids, liquids and
gases in solution. This subject has occupied a dominant position in
physico-chemical research since the investigations of van't Hoff and
Arrhenius. This subject is treated in the article SOLUTION; for the
properties of liquid mixtures reference should also be made to the
article DISTILLATION.

Another branch of physical chemistry has for its purpose the
quantitative study of chemical action, a subject which has brought out
in clear detail the analogies of chemical and physical equilibrium (see
CHEMICAL ACTION). Another branch, related to energetics (q.v.), is
concerned with the transformation of chemical energy into other forms of
energy--heat, light, electricity. Combustion is a familiar example of
the transformation of chemical energy into heat and light; the
quantitative measures of heat evolution or absorption (heat of
combustion or combination), and the deductions therefrom, are treated in
the article THERMOCHEMISTRY. Photography (q.v.) is based on chemical
action induced by luminous rays; apart from this practical application
there are many other cases in which actinic rays occasion chemical
actions; these are treated in the article PHOTOCHEMISTRY.
Transformations of electrical into chemical energy are witnessed in the
processes of electrolysis (q.v.; see also ELECTROCHEMISTRY and
ELECTROMETALLURGY). The converse is presented in the common electric
cell.

_Physical Properties and Composition._

For the complete determination of the chemical structure of any
compound, three sets of data are necessary: (1) the empirical chemical
composition of the molecule; (2) the constitution, i.e. the manner in
which the atoms are linked together; and (3) the configuration of the
molecule, i.e. the arrangement of the atoms in space. Identity in
composition, but difference in constitution, is generally known as
"isomerism" (q.v.), and compounds satisfying this relation differ in
many of their physical properties. If, however, two compounds only
differ with regard to the spatial arrangement of the atoms, the physical
properties may be (1) for the most part identical, differences, however,
being apparent with regard to the action of the molecules on polarized
light, as is the case when the configuration is due to the presence of
an asymmetric atom (optical isomerism); or (2) both chemical and
physical properties may be different when the configuration is
determined by the disposition of the atoms or groups attached to a pair
of doubly-linked atoms, or to two members of a ring system (geometrical
isomerism or allo-isomerism). Three sets of physical properties may
therefore be looked for: (1) depending on composition, (2) depending on
constitution, and (3) depending on configuration. The first set provides
evidence as to the molecular weight of a substance: these are termed
"colligative properties." The second and third sets elucidate the actual
structure of the molecule: these are known as "constitutional
properties."

In any attempts to gain an insight into the relations between the
physical properties and chemical composition of substances, the fact
must never be ignored that a comparison can only be made when the
particular property under consideration is determined under strictly
comparable conditions, in other words, when the molecular states of the
substances experimented upon are identical. This is readily illustrated
by considering the properties of gases--the simplest state of
aggregation. According to the law of Avogadro, equal volumes of
different gases under the same conditions of temperature and pressure
contain equal numbers of molecules; therefore, since the density depends
upon the number of molecules present in unit volume, it follows that for
a comparison of the densities of gases, the determinations must be made
under coincident conditions, or the observations reduced or re-computed
for coincident conditions. When this is done, such densities are
measures of the molecular weights of the substances in question.

_Volume Relations._[17]--When dealing with colligative properties of
liquids it is equally necessary to ensure comparability of conditions.
In the article CONDENSATION OF GASES (see also MOLECULE) it is shown
that the characteristic equation of gases and liquids is conveniently
expressed in the form (p + a/v²)(v - b) = RT. This equation, which is
mathematically deducible from the kinetic theory of gases, expresses the
behaviour of gases, the phenomena of the critical state, and the
behaviour of liquids; solids are not accounted for. If we denote the
critical volume, pressure and temperature by V_k, P_k and T_k, then it
may be shown, either by considering the characteristic equation as a
perfect cube in v or by using the relations that dp/dv = 0, d²p/dv² = 0
at the critical point, that V_k = 3b, P_k = a/27b², T^k = 8a/27b.
Eliminating a and b between these relations, we derive P_kV_k/T_k =
(3/8)R, a relation which should hold between the critical constants of
any substance. Experiment, however, showed that while the quotient on
the left hand of this equation was fairly constant for a great number of
substances, yet its value was not (3/8)R but (1/3.7)R; this means that
the critical density is, as a general rule, 3.7 times the theoretical
density. Deviation from this rule indicates molecular dissociation or
association. By actual observations it has been shown that ether,
alcohol, many esters of the normal alcohols and fatty acids, benzene,
and its halogen substitution products, have critical constants agreeing
with this originally empirical law, due to Sydney Young and Thomas;
acetic acid behaves abnormally, pointing to associated molecules at the
critical point.


    Volume at critical point and at absolute zero.

  The critical volume provides data which may be tested for additive
  relations. Theoretically the critical volume is three times the volume
  at absolute zero, i.e. the actual volume of the molecules; this is
  obvious by considering the result of making T zero in the
  characteristic equation. Experimentally (by extrapolation from the
  "law of the rectilinear diameter") the critical volume is four times
  the volume at absolute zero (see CONDENSATION or GASES). The most
  direct manner in which to test any property for additive relations is
  to determine the property for a number of elements, and then
  investigate whether these values hold for the elements in combination.
  Want of data for the elements, however, restricts this method to
  narrow limits, and hence an indirect method is necessary. It is found
  that isomers have nearly the same critical volume, and that equal
  differences in molecular content occasion equal differences in
  critical volume. For example, the difference due to an increment of
  CH2 is about 56.6, as is shown in the following table:--

    +--------------------+--------------+--------------+--------------+
    |      Name.         |   Formula.   |  Crit. Vol.  | Vol. per CH2 |
    +--------------------+--------------+--------------+--------------+
    | Methyl formate     | H·CO2CH3     | 171          |              |
    | Ethyl formate      | H·C02C2H5    | 228 \        |     56.5     |
    | Methyl acetate     | CH3·CO2CH3   | 227 /  227.5 |              |
    | Propyl formate     | H·CO2C3H7    | 284 \        |     55.8     |
    | Ethyl acetate      | CH3·C02C2H5  | 285  } 283.3 |              |
    | Methyl propionate  | C2H5·CO2CH3  | 28l /        |              |
    | Propyl acetate     | CH3·CO2C3H7  | 343 \        |     57.4     |
    | Ethyl propionate   | C2H5·CO2C2H5 | 343  } 340.7 |              |
    | Methyl n-butyrate  | }C3H7·CO2CH3 | 339  }       |              |
    | Methyl isobutyrate | }            | 337 /        |              |
    +--------------------+--------------+--------------+--------------+

  Since the critical volume of normal pentane C5H12 is 307.2, we have H2
  = C5H12 - 5CH2 = 307.2 - 5 X 56.6 = 24.2, and C = CH2 - H2 = 32.4. The
  critical volume of oxygen can be deduced from the data of the above
  table, and is found to be 29, whereas the experimental value is 25.


    Volume at boiling-point.

  The researches of H. Kopp, begun in 1842, on the molecular volumes,
  i.e. the volume occupied by one gramme molecular weight of a
  substance, of liquids measured at their boiling-point under
  atmospheric pressure, brought to light a series of additive relations
  which, in the case of carbon compounds, render it possible to predict,
  in some measure, the composition of the substance. In practice it is
  generally more convenient to determine the density, the molecular
  volume being then obtained by dividing the molecular weight of the
  substance by the density. By the indirect method Kopp derived the
  following atomic volumes:

    C.       O.       H.      Cl.      Br.      I.      S.
   11      12.2      5.5     22.8     27.8     37.5    22.6.

  These values hold fairly well when compared with the experimental
  values determined from other compounds, and also with the molecular
  volumes of the elements themselves. Thus the actually observed
  densities of liquid chlorine and bromine at the boiling-points are
  1.56 and 2.96, leading to atomic volumes 22.7 and 26.9, which closely
  correspond to Kopp's values deduced from organic compounds.

  These values, however, require modification in certain cases, for
  discrepancies occur which can be reconciled in some cases by assuming
  that the atomic value of a polyvalent element varies according to the
  distribution of its valencies. Thus a double bond of oxygen, as in the
  carbonyl group CO, requires a larger volume than a single bond, as in
  the hydroxyl group -OH, being about 12.2 in the first case and 7.8 in
  the second. Similarly, an increase of volume is associated with doubly
  and trebly linked carbon atoms.

  Recent researches have shown that the law originally proposed by
  Kopp--"That the specific volume of a liquid compound (molecular
  volume) at its boiling-point is equal to the sum of the specific
  volumes of its constituents (atomic volumes), and that every element
  has a definite atomic value in its compounds"--is by no means exact,
  for isomers have different specific volumes, and the volume for an
  increment of CH2 in different homologous series is by no means
  constant; for example, the difference among the esters of the fatty
  acids is about 57, whereas for the aliphatic aldehydes it is 49. We
  may therefore conclude that the molecular volume depends more upon the
  internal structure of the molecule than its empirical content. W.
  Ostwald (_Lehr. der allg. Chem._), after an exhaustive review of the
  material at hand, concluded that simple additive relations did exist
  but with considerable deviations, which he ascribed to differences in
  structure. In this connexion we may notice W. Städel's determinations:

    CH3CCl3        108           CHClBr·CH3      96·5
    CH2Cl·CHCl2    102.8         CH2Br·CH2Cl     88

  These differences do not disappear at the critical point, and hence
  the critical volumes are not strictly additive.

  Theoretical considerations as to how far Kopp was justified in
  choosing the boiling-points under atmospheric pressure as being
  comparable states for different substances now claim our attention.
  Van der Waal's equation (p+a/v²)(v-b) = RT contains two constants a
  and b determined by each particular substance. If we express the
  pressure, volume and temperature as fractions of the critical
  constants, then, calling these fractions the "reduced" pressure,
  volume and temperature, and denoting them by [pi], [phi] and [theta]
  respectively, the characteristic equation becomes
  ([pi]+3/[phi]²)(3[phi]-1) = 8[theta]; which has the same form for all
  substances. Obviously, therefore, liquids are comparable when the
  pressures, volumes and temperatures are equal fractions of the
  critical constants. In view of the extremely slight compressibility of
  liquids, atmospheric pressure may be regarded as a coincident
  condition; also C.M. Guldberg pointed out that for the most diverse
  substances the absolute boiling-point is about two-thirds of the
  critical temperature. Hence within narrow limits Kopp's determinations
  were carried out under coincident conditions, and therefore any
  regularities presented by the critical volumes should be revealed in
  the specific volumes at the boiling-point.


    Volume relations of solids.

  The connexion between the density and chemical composition of solids
  has not been investigated with the same completeness as in the case of
  gases and liquids. The relation between the atomic volumes and the
  atomic weights of the solid elements exhibits the periodicity which
  generally characterizes the elements. The molecular volume is additive
  in certain cases, in particular of analogous compounds of simple
  constitution. For instance, constant differences are found between the
  chlorides, bromides and iodides of sodium and potassium:--

    +------------+------+-------------+------+----------------+
    |     I.     |Diff. |      II.    | Diff.| Diff. I. & II. |
    +------------+------+-------------+------+----------------+
    | KCl = 37.4 | 6.9  | NaCl = 27.1 |  6.7 |      10.3      |
    | KBr = 44.3 | 9.7  | NaBr = 33.8 |  9.7 |      10.5      |
    | KI  = 54.0 |      |  NaI = 43.5 |      |      10.5      |
    +------------+------+-------------+------+----------------+

  According to H. Schroeder the silver salts of the fatty acids exhibit
  additive relations; an increase in the molecule of CH2 causes an
  increase in the molecular volume of about 15.3.

_Thermal Relations._

_Specific Heat and Composition._---The nature and experimental
determination of specific heats are discussed in the article
CALORIMETRY; here will be discussed the relations existing between the
heat capacities of elements and compounds.


  Specific heat of gases.

In the article THERMODYNAMICS it is shown that the amount of heat
required to raise a given weight of a gas through a certain range of
temperature is different according as the gas is maintained at constant
pressure, the volume increasing, or at constant volume, the pressure
increasing. A gas, therefore, has two specific heats, generally denoted
by C_p and C_v, when the quantity of gas taken as a unit is one gramme
molecular weight, the range of temperature being 1° C. It may be shown
that C_p - C_v = R, where R is the gas-constant, i.e. R in the equation
PV = RT. From the ratio C_p/C_v conclusions may be drawn as to the
molecular condition of the gas. By considerations based on the kinetic
theory of gases (see MOLECULE) it may be shown that when no energy is
utilized in separating the atoms of a molecule, this ratio is 5/3 =
1.67. If, however, an amount of energy a is taken up in separating
atoms, the ratio is expressible as C_p/C_v = (5+a)/(3+a), which is
obviously smaller than 5/3, and decreases with increasing values of a.
These relations may be readily tested, for the ratio C_p/C_v is capable
of easy experimental determination. It is found that mercury vapour,
helium, argon and its associates (neon, krypton, &c.) have the value
1.67; hence we conclude that these gases exist as monatomic molecules.
Oxygen, nitrogen, hydrogen and carbon monoxide have the value 1.4; these
gases have diatomic molecules, a fact capable of demonstration by other
means. Hence it may be inferred that this value is typical for diatomic
molecules. Similarly, greater atomic complexity is reflected in a
further decrease in the ratio C_p/C_v. The following table gives a
comparative view of the specific heats and the ratio for molecules of
variable atomic content.

  The abnormal specific heats of the halogen elements may be due to a
  loosening of the atoms, a preliminary to the dissociation into
  monatomic molecules which occurs at high temperatures. In the more
  complex gases the specific heat varies considerably with temperature;
  only in the case of monatomic gases does it remain constant. Le
  Chatelier (_Zeit. f. phys. Chem._ i. 456) has given the formula C_p
  = 6.5 + aT, where a is a constant depending on the complexity of the
  molecule, as an expression for the molecular heat at constant pressure
  at any temperature T (reckoned on the absolute scale). For a further
  discussion of the ratio of the specific heats see MOLECULE.

    +-----------+-------------------------+-------+-------+---------+
    | Molecular |        Examples.        |  C_p  |  C_v  | C_p/C_v |
    | Content.  |                         |       |       |         |
    +-----------+-------------------------+-------+-------+---------+
    | Monatomic | Hg, Zn, Cd, He, Ar, &c. |  5    |  3    |  1.66   |
    +-----------+-------------------------+-------+-------+---------+
    |           | H2, 02, N2 (0°-200°)    |  6.83 |  4.83 |  1.41   |
    | Diatomic  | Cl2, Br2, I2 (0°-200°)  |  8.6  |  6.6  |  1.30   |
    |           | HCl, HBr, HI, NO, CO    |       |       |  1.41   |
    +-----------+-------------------------+-------+-------+---------+
    | Triatomic | H2O, H2S, N2O, CO2      |  9.2  |  7.2  |  1.28   |
    +-----------+-------------------------+-------+-------+---------+
    | Tetratomic| As4, P4                 | 13.4  | 11.4  |  1.175  |
    |           | NH3, C2H2               | 11.6  |  9.6  |  1.21   |
    +-----------+-------------------------+-------+-------+---------+
    | Pentatomic| CHCl3                   | 14    | 12    |  1.17   |
    +-----------+-------------------------+-------+-------+---------+
    | Hexatomic | C2H4, C2H3Br            | 16.4  | 14.4  |  1.14   |
    +-----------+-------------------------+-------+-------+---------+

_Specific Heats of Solids._--The development of the atomic theory and
the subsequent determination of atomic weights in the opening decades of
the 19th century inspired A.T. Petit and P.L. Dulong to investigate
relations (if any) existing between specific heats and the atomic
weight. Their observations on the solid elements led to a remarkable
generalization, now known as Dulong and Petit's law. This states that
"the atomic heat (the product of the atomic weight and specific heat) of
all elements is a constant quantity." The value of this constant when H
= 1 is about 6.4; Dulong and Petit, using O = 1, gave the value .38, the
specific heat of water being unity in both cases. This law--purely
empirical in origin--was strengthened by Berzelius, who redetermined
many specific heats, and applied the law to determine the true atomic
weight from the equivalent weight. At the same time he perceived that
specific heats varied with temperature and also with allotropes, e.g.
graphite and diamond. The results of Berzelius were greatly extended by
Hermann Kopp, who recognized that carbon, boron and silicon were
exceptions to the law. He regarded these anomalies as solely due to the
chemical nature of the elements, and ignored or regarded as
insignificant such factors as the state of aggregation and change of
specific heat with temperature.

  The specific heats of carbon, boron and silicon subsequently formed
  the subject of elaborate investigations by H.F. Weber, who showed that
  with rise of temperature the specific (and atomic) heat increases,
  finally attaining a fairly constant value; diamond, graphite and the
  various amorphous forms of carbon having the value about 5.6 at 1000°,
  and silicon 5.68 at 232°; while he concluded that boron attained a
  constant value of 5.5. Niison and Pettersson's observations on
  beryllium and germanium have shown that the atomic heats of these
  metals increase with rise of temperature, finally becoming constant
  with a value 5.6. W.A. Tilden (_Phil. Trans._, 1900, p. 233)
  investigated nickel and cobalt over a wide range of temperature (from
  -182.5° to 100°); his results are:--

    +--------------------------+---------+---------+
    |                          | Cobalt. | Nickel. |
    +--------------------------+---------+---------+
    | From -182.5° to -78.4°   | 4.1687  | 4.1874  |
    |       -78.4° to  15°     | 5.4978  | 5.6784  |
    |        15°   to 100°     | 6.0324  | 6.3143  |
    +--------------------------+---------+---------+

  It is evident that the atomic heats of these intimately associated
  elements approach nearer and nearer as we descend in temperature,
  approximating to the value 4. Other metals were tested in order to
  determine if their atomic heats approximated to this value at low
  temperatures, but with negative results.

  It is apparent that the law of Dulong and Petit is not rigorously
  true, and that deviations are observed which invalidate the law as
  originally framed. Since the atomic heat of the same element varies
  with its state of aggregation, it must be concluded that some factor
  taking this into account must be introduced; moreover, the variation
  of specific heat with temperature introduces another factor.

We now proceed to discuss molecular heats of compounds, that is, the
product of the molecular weight into the specific heat. The earliest
generalization in this direction is associated with F.E. Neumann, who,
in 1831, deduced from observations on many carbonates (calcium,
magnesium, ferrous, zinc, barium and lead) that stoichiometric
quantities (equimolecular weights) of compounds possess the same heat
capacity. This is spoken of as "Neumann's law." Regnault confirmed
Neumann's observations, and showed that the molecular heat depended on
the number of atoms present, equiatomic compounds having the same
molecular heat. Kopp systematized the earlier observations, and, having
made many others, he was able to show that the molecular heat was an
additive property, i.e. each element retains the same heat capacity when
in combination as in the free state. This has received confirmation by
the researches of W.A. Tilden (_Phil. Trans._, 1904, 203 A, p.139) for
those elements whose atomic heats vary considerably with temperature.

  The specific heat of a compound may, in general, be calculated from
  the specific heats of its constituent elements. Conversely, if the
  specific heats of a compound and its constituent elements, except one,
  be known, then the unknown atomic heat is readily deducible.
  Similarly, by taking the difference of the molecular heats of
  compounds differing by one constituent, the molecular (or atomic) heat
  of this constituent is directly obtained. By this method it is shown
  that water, when present as "water of crystallization," behaves as if
  it were ice.

_Deductions from Dulong and Petit's Law._--Denoting the atomic weight by
W and the specific heat by s, Dulong and Petit's law states that 6.4 =
Ws. Thus if s be known, an approximate value of W is determinate. In the
determination of the atomic weight of an element two factors must be
considered: (1) its equivalent weight, i.e. the amount which is
equivalent to one part of hydrogen; and (2) a factor which denotes the
number of atoms of hydrogen which combines with or is equivalent to one
atom of the particular element. This factor is termed the valency. The
equivalent weight is capable of fairly ready determination, but the
settlement of the second factor is somewhat more complex, and in this
direction the law of atomic heats is of service. To take an example: 38
parts of indium combine with 35.4 parts of chlorine; hence, if the
formula of the chloride be InCl, InCl2 or InCl3, indium has the atomic
weights 38, 76 or 114. The specific heat of indium is 0.057; and the
atomic heats corresponding to the atomic weights 38, 76 and 114 are 3.2,
4.3, 6.5. Dulong and Petit's law thus points to the value 114, which is
also supported by the position occupied by this element in the periodic
classification. C. Winkler decided the atomic weight of germanium by
similar reasoning.

_Boiling-Point and Composition._--From the relation between the critical
constants P_kV_k/T_k = (1/3.7)R or T_k/P_k = 3.7V_k/R, and since V_k is
proportional to the volume at absolute zero, the ratio T_k/P_k should
exhibit additive relations. This ratio, termed by Guye the critical
coefficient, has the following approximate values:--

                                                         Double   Triple
   C.      H.    Cl.   -O-.    =O.    N.    N=.    P.   linkage. linkage.
  1.35   0.57   2.66   0.87   1.27   1.6   1.86   3.01    0.88     1.03

Since at the boiling-point under atmospheric pressure liquids are in
corresponding states, the additive nature of the critical coefficient
should also be presented by boiling-points. It may be shown
theoretically that the absolute boiling-point is proportional to the
molecular volume, and, since this property is additive, the
boiling-point should also be additive.

  These relations have been more thoroughly tested in the case of
  organic compounds, and the results obtained agree in some measure with
  the deductions from molecular volumes. In general, isomers boil at
  about the same temperature, as is shown by the isomeric esters
  C9H18O2:--

    Methyl octoate   192.9°      Amyl butyrate    184.8°
    Ethyl heptoate   187.1°      Heptyl acetate   191.3°
    Propyl hexoate   185.5°      Octyl formate    198.1°
    Butyl pentoate   185.8

  Equal increments in the molecule are associated with an equal rise in
  the boiling-point, but this increment varies in different homologous
  series. Thus in the normal fatty alcohols, acids, esters, nitriles and
  ketones, the increment per CH2 is 19°-21°; in the aldehydes it is
  26°-27°. In the aromatic compounds there is no regularity between the
  increments due to the introduction of methyl groups into the benzene
  nucleus or side chains; the normal value of 20°-21° is exhibited,
  however, by pyridine and its derivatives. The substitution of a
  hydrogen atom by the hydroxyl group generally occasions a rise in
  boiling-point at about 100°. The same increase accompanies the
  introduction of the amino group into aromatic nuclei.


    Constitutive influences.

  While certain additive relations hold between some homologous series,
  yet differences occur which must be referred to the constitution of
  the molecule. As a general rule, compounds formed with a great
  evolution of heat have high boiling-points, and vice versa. The
  introduction of negative groups into a molecule alters the
  boiling-point according to the number of negative groups already
  present. This is shown in the case of the chloracetic acids:

                                 Diff.
       CH3CO2H = 118°
                                  67°
    ClCH2·CO2H = 185°
                                  10°
    Cl2CH·CO2H = 195°
                                   3°
     Cl3C·CO2H = 195°-200°

  According to van 't Hoff the substitution of chlorine atoms into a
  methyl group occasions the following increments:--

    Cl in CH3    66°
    Cl  " CH2Cl  39°
    Cl  " CHCl2  13°.

  The introduction of chlorine, however, may involve a fall in the
  boiling-point, as is recorded by Henry in the case of the chlorinated
  acetonitriles:--

    NC·CH3.     NC·CH2Cl.     NC·CHC12.     NC·CC13.
      81°         123°          112°           83°
           42°          -11°           -29°

  The replacement of one negative group by another is accompanied by a
  change in the boiling-point, which is independent of the compound in
  which the substitution is effected, and solely conditioned by the
  nature of the replaced and replacing groups. Thus bromine and iodine
  replace chlorine with increments of about 22° and 50° respectively.

  A factor of considerable importance in determining boiling-points of
  isomers is the symmetry of the molecule. Referring to the esters
  C9H18O2 previously mentioned, it is seen that the highest
  boiling-points belong to methyl octoate and octyl formate, the least
  symmetrical, while the minimum belongs to amyl butyrate, the most
  symmetrical. The isomeric pentanes also exhibit a similar relation
  CH3(CH2)4CH3 = 38°, (CH3)2CHC2H5 = 30°, (CH3)4C = 9.5°. For a similar
  reason secondary alcohols boil at a lower temperature than the
  corresponding primary, the difference being about 19°. A.E. Earp
  (_Phil. Mag._, 1893 [5], 35, p. 458) has shown that, while an increase
  in molecular weight is generally associated with a rise in the
  boiling-point, yet the symmetry of the resulting molecule may exert
  such a lowering effect that the final result is a diminution in the
  boiling-point. The series H2S = -61°, CH3SH = 21°, (CH3)2S = 41° is
  an example; in the first case, the molecular weight is increased and
  the symmetry diminished, the increase of boiling-point being 82°; in
  the second case the molecular weight is again increased but the
  molecule assumes a more symmetrical configuration, hence the
  comparatively slight increase of 20°. A similar depression is
  presented by methyl alcohol (67°) and methyl ether (-23°).

  Among the aromatic di-substitution derivatives the _ortho_ compounds
  have the highest boiling-point, and the _meta_ boil at a higher, or
  about the same temperature as the _para_ compounds. Of the
  tri-derivatives the symmetrical compounds boil at the lowest
  temperature, the asymmetric next, and the vicinal at the highest.

  An ethylenic or double carbon union in the aliphatic hydrocarbons has,
  apparently, the same effect on the boiling-point as two hydrogen
  atoms, since the compounds C_{n}H_{2n+2} and C_{n}H_{2n} boil at about
  the same temperature. An acetylenic or triple linkage is associated
  with a rise in the boiling-point; for example, propargyl compounds
  boil about 19.5° higher than the corresponding propyl compound.

  Certain regularities attend the corresponding property of the
  melting-point. A rule applicable to organic compounds, due to Adolf v.
  Baeyer and supported by F.S. Kipping (_Jour. Chem. Soc._, 1893, 63,
  p.465) states, that the melting-point of any odd member of a
  homologous series is lower than the melting-point of the even member
  containing one carbon atom less. This is true of the fatty acid
  series, and the corresponding ketones and alcohols, and also of the
  succinic acid series. Other regularities exist, but generally with
  many exceptions. It is to be noted that although the correlation of
  melting-point with constitution has not been developed to such an
  extent as the chemical significance of other physical properties, the
  melting-point is the most valuable test of the purity of a substance,
  a circumstance due in considerable measure to the fact that impurities
  always tend to lower the melting-point.

_Heat of Combustion and Constitution._--In the article THERMOCHEMISTRY a
general account of heats of formation of chemical compounds is given,
and it is there shown that this constant measures the stability of the
compound. In organic chemistry it is more customary to deal with the
"heat of combustion," i.e. the heat evolved when an organic compound is
completely burned in oxygen; the heat of formation is deduced from the
fact that it is equal to the heats of formation of the products of
combustion less the observed heat of combustion. The researches of
Julius Thomsen and others have shown that in many cases definite
conclusions regarding constitution can be drawn from quantitative
measurements of the heats of combustion; and in this article a summary
of the chief results will be given.

  The identity of the four valencies of the carbon atom follows from the
  fact that the heats of combustion of methane, ethane, propane,
  trimethyl methane, and tetramethyl methane, have a constant difference
  in the order given, viz. 158.6 calories; this means that the
  replacement of a hydrogen atom by a methyl group is attended by a
  constant increase in the heat of combustion. The same difference
  attends the introduction of the methyl group into many classes of
  compounds, for example, the paraffins, olefines, acetylenes, aromatic
  hydrocarbons, alcohols, aldehydes, ketones and esters, while a
  slightly lower value (157.1) is found in the case of the halogen
  compounds, nitriles, amines, acids, ethers, sulphides and nitro
  compounds. It therefore appears that the difference between the heats
  of combustion of two adjacent members of a series of homologous
  compounds is practically a constant, and that this constant has two
  average values, viz. 158.6 and 157.1.

  An important connexion between heats of combustion and constitution is
  found in the investigation of the effect of single, double and triple
  carbon linkages on the thermochemical constants. If twelve grammes of
  amorphous carbon be burnt to carbon dioxide under constant volume, the
  heat evolved (96.96 cal.) does not measure the entire thermal effect,
  but the difference between this and the heat required to break down
  the carbon molecule into atoms. If the number of atoms in the carbon
  molecule be denoted by n, and the heat required to split off each atom
  from the molecule by d, then the total heat required to break down a
  carbon molecule completely into atoms is nd. It follows that the true
  heat of combustion of carbon, i.e. the heat of combustion of one
  gramme-atom, is 96.96 + d. The value of d can be evaluated by
  considering the combustion of amorphous carbon to carbon monoxide and
  carbon dioxide. In the first case the thermal effect of 58.58 calories
  actually observed must be increased by 2d to allow for the heat
  absorbed in splitting off two gramme-atoms of carbon; in the second
  case the thermal effect of 96.96 must be increased by d as above. Now
  in both cases one gramme-molecule of oxygen is decomposed, and the two
  oxygen atoms thus formed are combined with two carbon valencies. It
  follows that the thermal effects stated above must be equal, i.e.
  58.58 + 2d = 96.96 + d, and therefore d = 38.38. The absolute heat of
  combustion of a carbon _atom_ is therefore 135.34 calories, and this
  is independent of the form of the carbon burned.

  Consider now the combustion of a hydrocarbon of the general formula
  C_{n}H_{2m}. We assume that each carbon atom and each hydrogen atom
  contributes equally to the thermal effect. If [alpha] be the heat
  evolved by each carbon atom, and [beta] that by each hydrogen atom,
  the thermal effect may be expressed as H = n[alpha] + 2m[beta] - A,
  where A is the heat required to break the molecule into its
  constituent atoms. If the hydrocarbon be saturated, i.e. only contain
  single carbon linkages, then the number of such linkages is 2n - m,
  and if the thermal effect of such a linkage be X, then the term A is
  obviously equal to (2n - m)X. The value of H then becomes H = n[alpha]
  + 2m[beta] - (2n - m)X or n[xi] + m[nu], where [xi] and [nu] are
  constants. Let double bonds be present, in number p, and let the
  energy due to such a bond be Y. Then the number of single bonds is 2n
  - m - 2p, and the heat of combustion becomes H1 = n[xi] + m[nu] +
  p(2X - Y). If triple bonds, q in number, occur also, and the energy of
  such a bond be Z, the equation for H becomes

    H = n[xi] + m[nu] + p(2X - Y) + q(3X - Z).

  This is the general equation for calculating the heat of combustion of
  a hydrocarbon. It contains four independent constants; two of these
  may be calculated from the heats of combustion of saturated
  hydrocarbons, and the other two from the combustion of hydrocarbons
  containing double and triple linkages. By experiment it is found that
  the thermal effect of a double bond is much less than the effect of
  two single bonds, while a triple bond has a much smaller effect than
  three single bonds. J. Thomsen deduces the actual values of X, Y, Z to
  be 14.71, 13.27 and _zero_; the last value he considers to be in
  agreement with the labile equilibrium of acetylenic compounds. One of
  the most important applications of these values is found in the case
  of the constitution of benzene, where Thomsen decides in favour of the
  Claus formula, involving nine single carbon linkages, and rejects the
  Kekulé formula, which has three single and three double bonds (see
  section IV.).

  The thermal effects of the common organic substituents have also been
  investigated. The thermal effect of the "alcohol" group C·OH may be
  determined by finding the heat of formation of the alcohol and
  subtracting the thermal effects of the remaining linkages in the
  molecule. The average value for primary alcohols is 44.67 cal., but
  many large differences from this value obtain in certain cases. The
  thermal effects increase as one passes from primary to tertiary
  alcohols, the values deduced from propyl and isopropyl alcohols and
  trimethyl carbinol being:--primary = 45.08, secondary = 50.39,
  tertiary = 60.98. The thermal effect of the aldehyde group has the
  average value 64.88 calories, i.e. considerably greater than the
  alcohol group. The ketone group corresponds to a thermal effect of
  53.52 calories. It is remarkable that the difference in the heats of
  formation of ketones and the paraffin containing one carbon atom less
  is 67.94 calories, which is the heat of formation of carbon monoxide
  at constant volume. It follows therefore that two hydrocarbon radicals
  are bound to the carbon monoxide residue with the same strength as
  they combine to form a paraffin. The average value for the carboxyl
  group is 119.75 calories, i.e. it is equal to the sum of the thermal
  effects of the aldehyde and carbonyl groups.

  The thermal effects of the halogens are: chlorine = l5.13 calories,
  bromine = 7.68; iodine = -4.25 calories. It is remarkable that the
  position of the halogen in the molecule has no effect on the heat of
  formation; for example, chlorpropylene and allylchloride, and also
  ethylene dichloride and ethylidene dichloride, have equal heats of
  formation. The thermal effect of the ether group has an average value
  of 34.31 calories. This value does not hold in the case of methylene
  oxide if we assign to it the formula H2C·[O·CH2], but if the formula
  H2C·O·CH2 (which assumes the presence of two free valencies) be
  accepted, the calculated and observed heats of formation are in
  agreement.

  The combination of nitrogen with carbon may result in the formation of
  nitriles, cyanides, or primary, secondary or tertiary amines. Thomsen
  deduced that a single bond between a carbon and a nitrogen gramme-atom
  corresponds to a thermal effect of 2.77 calories, a double bond to
  5.44, and a treble bond to 8.31. From this he infers that cyanogen is
  C:N·N:C and not N÷C-C÷N, that hydrocyanic acid is HC·N, and
  acetonitrile CH3·C÷N. In the case of the amines he decides in favour
  of the formulae

    H2C:NH3            H2C               H2C
                         \\                \\
                           NH2               NH·CH3
                          /                 /
                       H3C               H3C
    primary,        secondary,     tertiary.

  These involve pentavalent nitrogen. These formulae, however, only
  apply to aliphatic amines; the results obtained in the aromatic series
  are in accordance with the usual formulae.

_Optical Relations_.

_Refraction and Composition._--Reference should be made to the article
REFRACTION for the general discussion of the phenomenon known as the
refraction of light. It is there shown that every substance, transparent
to light, has a definite refractive index, which is the ratio of the
velocity of light _in vacuo_ to its velocity in the medium to which the
refractive index refers. The refractive index of any substance varies
with (1) the wave-length of the light; (2) with temperature; and (3)
with the state of aggregation. The first cause of variation may be at
present ignored; its significance will become apparent when we consider
dispersion (_vide infra_).The second and third causes, however, are of
greater importance, since they are associated with the molecular
condition of the substance; hence, it is obvious that it is only from
some function of the refractive index which is independent of
temperature variations and changes of state (i.e. it must remain
constant for the same substance at any temperature and in any form) that
quantitative relations between refractivity and chemical composition can
be derived.

The pioneer work in this field, now frequently denominated
"spectro-chemistry," was done by Sir Isaac Newton, who, from theoretical
considerations based on his corpuscular theory of light, determined the
function (n²-1), where n is the refractive index, to be the expression
for the refractive power; dividing this expression by the density (d), he
obtained (n²-1)/d, which he named the "absolute refractive power." To
P.S. Laplace is due the theoretical proof that this function is
independent of temperature and pressure, and apparent experimental
confirmation was provided by Biot and Arago's, and by Dulong's
observations on gases and vapours. The theoretical basis upon which this
formula was devised (the corpuscular theory) was shattered early in the
19th century, and in its place there arose the modern wave theory which
theoretically invalidates Newton's formula. The question of the
dependence of refractive index on temperature was investigated in 1858
by J.H. Gladstone and the Rev. T.P. Dale; the more simple formula
(n-1)/d, which remained constant for gases and vapours, but exhibited
slight discrepancies when liquids were examined over a wide range of
temperature, being adopted. The subject was next taken up by Hans
Landolt, who, from an immense number of observations, supported in a
general way the formula of Gladstone and Dale. He introduced the idea of
comparing the refractivity of equimolecular quantities of different
substances by multiplying the function (n-1)/d by the molecular weight
(M) of the substance, and investigated the relations of chemical
grouping to refractivity. Although establishing certain general
relations between atomic and molecular refractions, the results were
somewhat vitiated by the inadequacy of the empirical function which he
employed, since it was by no means a constant which depended only on the
actual composition of the substance and was independent of its physical
condition. A more accurate expression (n²-1)/(n²+2)d was suggested in
1880 independently and almost simultaneously by L.V. Lorenz of
Copenhagen and H.A. Lorentz of Leiden, from considerations based on the
Clausius-Mossotti theory of dielectrics.

  Assuming that the molecules are spherical, R.J.E. Clausius and O.F.
  Mossotti found a relation between the dielectric constant and the
  space actually occupied by the molecules, viz. K = (1 + 2a)/(1 - a),
  or a = (K - 1)/(K + 2), where K is the dielectric constant and a the
  fraction of the total volume actually occupied by matter. According to
  the electromagnetic theory of light K = N², where N is the refractive
  index for rays of infinite wave-length. Making this substitution, and
  dividing by d, the density of the substance, we obtain a/d = (N² -
  1)/(N² + 2 )d. Since a/d is the real specific volume of the molecule,
  it is therefore a constant; hence (N² - 1)/(N² + 2)d is also a
  constant and is independent of all changes of temperature, pressure,
  and of the state of aggregation. To determine N recourse must be made
  to Cauchy's formula of dispersion (q.v.), n = A + B/[lambda]^2 +
  C/[lambda]^4 + ... from which, by extrapolation, [lambda] becoming
  infinite, we obtain N = A. In the case of substances possessing
  anomalous dispersion, the direct measurement of the refractive index
  for Hertzian waves of very long wave-length may be employed.

It is found experimentally that the Lorenz and Lorentz function holds
fairly well, and better than the Gladstone and Dale formula. This is
shown by the following observations of Rühlmann on water, the light used
being the D line of the spectrum:--

  +------+------------+---------------------+
  |  t.  | (n - 1)/d. | (n² - 1)/(n² + 2)d. |
  +------+------------+---------------------+
  |   0  |   0.3338   |       0.2061        |
  |  10  |   0.3338   |       0.2061        |
  |  20  |   0.3336   |       0.2061        |
  |  90  |   0.3321   |       0.2059        |
  | 100  |   0.3323   |       0.2061        |
  +------+------------+---------------------+

Eykmann's observations also support the approximate constancy of the
Lorenz-Lorentz formula over wide temperature differences, but in some
cases the deviation exceeds the errors of observation. The values are
for the H[alpha] line:--

  +----------------------------+----------+---------------------+
  |     Substance.             |   Temp.  | (n² - 1)/(n² + 2)d. |
  +----------------------------+----------+---------------------+
  | Isosafrol, C10H10O2        | /  17.6° |        0.2925       |
  |                            | \ 141.2° |        0.2962       |
  | Diphenyl ethylene, C14H12  | /  22°   |        0.3339       |
  |                            | \ 143.4° |        0.3382       |
  | Quinoline, C9H7N           | /  16.2° |        0.3187       |
  |                            | \ 141°   |        0.3225       |
  +----------------------------+----------+---------------------+

The empirical formula (n² - 1)/(n² + 0.4)d apparently gives more
constant values with change of temperature than the Lorenz-Lorentz form.
The superiority of the Lorenz-Lorentz formula over the Gladstone and
Dale formula for changes of state is shown by the following observations
of Brühl (_Zeit. f. phys. Chem._, 1891, 71, p. 4). The values are for
the D line:--

  +-------------------+-------+---------------------+---------------------+
  |                   |       | Gladstone and Dale. | Lorenz and Lorentz. |
  |     Substance.    | Temp. +----------+----------+---------+-----------+
  |                   |       |  Vapour. | Liquid.  | Vapour. |  Liquid.  |
  +-------------------+-------+----------+----------+---------+-----------+
  | Water             |  10°  |  0.3101  | 0.3338   | 0.2068  |  0.2061   |
  | Carbon disulphide |  10°  |  0.4347  | 0.4977   | 0.2898  |  0.2805   |
  | Chloroform        |  10°  |  0.2694  | 0.3000   | 0.1796  |  0.1790   |
  +-------------------+-------+----------+----------+---------+-----------+


  [Sidenote: Additive relations.]

  Landolt and Gladstone, and at a later date J.W. Brühl, have
  investigated the relations existing between the refractive power and
  composition. To Landolt is due the proof that, in general, isomers,
  i.e. compounds having the same composition, have equal molecular
  refractions, and that equal differences in composition are associated
  with equal differences in refractive power. This is shown in the
  following table (the values are for H[alpha]):

    +------------------------------+--------+-----------------+--------+-----------+
    |          Substance.          |  Mol.  |    Substance.   |Mol.    | Diff. for |
    |                              |Refract.|                 |Refract.|    CH2.   |
    +------------------------------+--------+-----------------+--------+-----------+
    | Ethylene chloride  \ C2H4Cl2 | 20.96  | Acetic acid     | 12.93  |  / 4.49   |
    | Ethylidene chloride/         | 21.08  | Propionic acid  | 17.42  |  \        |
    | Fumaric acid  \ C4H4O4       | 70.89  | Butyric acid    | 22.01  |  / 4.59   |
    | Maleic acid   /              | 70.29  |                 |        |  \        |
    | o-Cresol     \               | 32.52  | Acetaldehyde    | 11.50  |  / 4.43   |
    | m-Cresol      } C7H8O        | 32.56  | Propionaldehyde | 15.93  |  \        |
    | p-Cresol     /               | 32.57  | Butylaldehyde   | 20.52  |  / 4.59   |
    +------------------------------+--------+-----------------+--------+-----------+

  Additive relations undoubtedly exist, but many discrepancies occur
  which may be assigned, as in the case of molecular volumes, to
  differences in constitution. Atomic refractions may be obtained either
  directly, by investigating the various elements, or indirectly, by
  considering differences in the molecular refractions of related
  compounds. The first method needs no explanation. The second method
  proceeds on the same lines as adopted for atomic volumes. By
  subtracting the value for CH2, which may be derived from two
  substances belonging to the same homologous series, from the molecular
  refraction of methane, CH4, the value of hydrogen is obtained;
  subtracting this from CH2, the value of carbon is determined.
  Hydroxylic oxygen is obtained by subtracting the molecular refractions
  of acetic acid and acetaldehyde. Similarly, by this method of
  differences, the atomic refraction of any element may be determined.
  It is found, however, that the same element has not always the same
  atomic refraction, the difference being due to the nature of the
  elements which saturate its valencies. Thus oxygen varies according as
  whether it is linked to hydrogen (hydroxylic oxygen), to two atoms of
  carbon (ether oxygen), or to one carbon atom (carbonyl oxygen);
  similarly, carbon varies according as whether it is singly, doubly, or
  trebly bound to carbon atoms.

  A table of the atomic refractions and dispersions of the principal
  elements is here given:--

    +--------------------------+--------+-------+--------+---------------+
    |                          |        |       |        |  Dispersion   |
    |         Element.         |H[alpha]|   D.  |H[gamma]|     H[gamma]- |
    |                          |        |       |        | H[alpha]      |
    +--------------------------+--------+-------+--------+---------------+
    | Hydrogen                 | 1.103  | 1.051 |  1.139 |    0.036      |
    | Oxygen, hydroxyl         | 1.506  | 1.521 |  1.525 |    0.019      |
    | Oxygen, ether            | 1.655  | 1.683 |  1.667 |    0.012      |
    | Oxygen, carbonyl         | 2.328  | 2.287 |  2.414 |    0.086      |
    | Chlorine                 | 6.014  | 5.998 |  6.190 |    0.176      |
    | Bromine                  | 8.863  | 8.927 |  9.211 |    0.348      |
    | Iodine                   |13.808  |14.12  | 14.582 |    0.774      |
    | Carbon (singly bound)    | 2.365  | 2.501 |  2.404 |    0.039      |
    | Double linkage of carbon | 1.836  | 1.707 |  1.859 |    0.23       |
    | Triple                   | 2.22   |       |  2.41  |    0.19       |
    | Nitrogen, singly bound   |        |       |        |               |
    |   and only to carbon     | 2.76   |       |  2.95  |    0.19       |
    +--------------------------+--------+-------+--------+---------------+

  _Dispersion and Composition._---In the preceding section we have seen
  that substances possess a definite molecular (or atomic) refraction
  for light of particular wave-length; the difference between the
  refractions for any two rays is known as the molecular (or atomic)
  dispersion. Since molecular refractions are independent of temperature
  and of the state of aggregation, it follows that molecular dispersions
  must be also independent of these conditions; and hence quantitative
  measurements should give an indication as to the chemical composition
  of substances. This subject has been principally investigated by
  Brühl; he found that molecular dispersions of liquids and gases were
  independent of temperature, and fairly independent of the state of
  aggregation, but that no simple connexion exists between atomic
  refractions and dispersions (see preceding table). He also showed how
  changes in constitution effected dispersions to a far greater extent
  than they did refractions; thus, while the atomic dispersion of carbon
  is 0.039, the dispersions due to a double and treble linkage is 0.23
  and 0.19 respectively.

_Colour and Constitution._--In this article a summary of the theories
which have been promoted in order to connect the colour of organic
compounds with their constitution will be given, and the reader is
referred to the article COLOUR for the physical explanation of this
property, and to VISION for the physiological and psychological
bearings. A clear distinction must be drawn between colour and the
property of dyeing; all coloured substances are not dyes, and it is
shown in the article DYEING that the property of entering into chemical
or physical combination with fibres involves properties other than those
essential to colour. At the same time, however, all dyestuffs are
coloured substances.

  A survey of coloured substances led O.N. Witt in 1876 to formulate his
  "chromophore-auxochrome" theory. On this theory colour is regarded as
  due to the presence of a "chromophore," and dyeing power to an
  "auxochrome"; the latter by itself cannot produce colour or dyeing
  power, but it is only active in the presence of a chromophore, when it
  intensifies the colour and confers the property of dyeing. The
  principal chromophores are the azo, -N=N-, azoxy, =N2O, nitro, -NO2,
  nitroso, -NO, and carbonyl, =CO, groups. The azo-group is particularly
  active, both the aliphatic and aromatic compounds being coloured. The
  simplest aliphatic compounds, such as diazo-methane, diazo-ethane, and
  azo-formic acid, are yellow; the diamide of the latter acid is
  orange-red. Of the aromatic compounds azo-benzene is bright
  orange-red, and [alpha]-azo-naphthalene forms red needles or small
  steel-blue prisms. The azo-group, however, has little or no colouring
  effect when present in a ring system, such as in cinnolene,
  phthalazine and tolazone. The nitro group has a very important action
  mainly on account of the readiness with which it can be introduced
  into the molecule, but its effect is much less than that of the azo
  group. The colour produced is generally yellow, which, in accordance
  with a general rule, is intensified with an increase in the number of
  groups; compare, for example, mono-, di-and tri-nitrobenzene. The
  nitroso group is less important. The colour produced is generally of a
  greenish shade; for example, nitrosobenzene is green when fused or in
  solution (when crystalline, it is colourless), and dinitrosoresorcin
  has been employed as a dyestuff under the names "solid green" and
  "chlorine." The carbonyl group by itself does not produce colour, but
  when two adjacent groups occur in the molecule, as for example in the
  a-diketones (such as di-acetyl and benzil), a yellow colour is
  produced. It also acts as a chromogenic centre when double bonds or
  ethylenic linkages are present, as in fluorene ketone or fluorenone. A
  more complex chromophoric group is the triple ethylenic grouping

    =C\
       >C=,
    =C/

  the introduction of which was rendered necessary by the
  discovery of certain coloured hydrocarbons. As a general rule,
  hydrocarbons are colourless; the exceptions include the golden yellow
  acenaphthylene, the red bidiphenylene-ethylene, and the derivatives of
  fulvene

    CH:CH \
           >CH2,
    CH:CH /

  which have been discussed by J. Thiele (_Ber._, 1900, 33, p. 666).
  This grouping is not always colour-producing, since diphenyl is
  colourless.

  The most important auxochromes are the hydroxyl (-OH) and amino (-NH2)
  groups. According to the modern theory of auxochromic action, the
  introduction of a group into the molecule is accompanied by some
  strain, and the alteration in colour produced is connected with the
  magnitude of the strain. The amino group is more powerful than the
  hydroxyl, and the substituted amino group more powerful still; the
  repeated substitution of hydroxyl groups sometimes causes an
  intensification and sometimes a diminution of colour.

  We may here notice an empirical rule formulated by Nietzski in
  1879:--the simplest colouring substances are in the greenish-yellow
  and yellow, and with increasing molecular weight the colour passes
  into orange, red, violet, blue and green. This rule, however, is by no
  means perfect. Examination of the absorption spectra of coloured
  compounds shows that certain groupings displace the absorption bands
  in one direction, and other groupings in the other. If the bands be
  displaced towards the violet, involving a regression through the
  colours mentioned above, the group is said to be "hypsochromic"; if
  the reverse occurs the group is "bathochromic." It may be generally
  inferred that an increase in molecular weight is accompanied by a
  change in colour in the direction of the violet.

  Auxochromic groups generally aid one another, i.e. the tint deepens as
  the number of auxochromes increases. Also the relative position of the
  auxochrome to the chromophore influences colour, the ortho-position
  being generally the most powerful. Kauffmann (_Ber._, 1906, 39, p.
  1959) attempted an evaluation of the effects of auxochromic groups by
  means of the magnetic optical constants. The method is based on the
  supposition that the magnetic rotation measures the strain produced in
  the molecule by an auxochrome, and he arranges the groups in the
  following order:--

    ·OCOCH3     ·OCH3     ·NHCOCH3     ·NH2     ·N(CH3)2     ·N(C2H5)2
     -0.260     1.459      1.949       3.821      8.587         8.816

  The phenomena attending the salt formation of coloured and colouring
  substances are important. The chromophoric groups are rarely strongly
  acid or basic; on the other hand, the auxochromes are strongly acid or
  basic and form salts very readily. Notable differences attend the
  neutralization of the chromophoric and auxochromic groups. With basic
  substances, the chromophoric combination with a colourless acid is
  generally attended by a deepening in colour; auxochromic combination,
  on the other hand, with a lessening. Examples of the first case are
  found among the colourless acridines and quinoxalines which give
  coloured salts; of the second case we may notice the colourless
  hydrochloride and sulphate of the deep yellow o-aminobenzophenone.
  With acid substances, the combination with "colourless" metals, i.e.
  metals producing colourless salts with acids, is attended by colour
  changes contrary to those given above, auxochromic combination being
  accompanied by a deepening, and chromophoric by a lessening of the
  tint.

  Mention may be made of the phenomenon of halochromism, the name given
  to the power of colourless or faintly-coloured substances of combining
  with acids to form highly-coloured substances without the necessary
  production of a chromophoric group. The researches of Adolf von Baeyer
  and Villiger, Kehrmann, Kauffmann and others, show that this property
  is possessed by very many and varied substances. In many cases it may
  be connected with basic oxygen, and the salt formation is assumed to
  involve the passage of divalent into tetravalent oxygen. It seems that
  intermolecular change also occurs, but further research is necessary
  before a sound theory can be stated.

  _Quinone Theory of Colour._--A theory of colour in opposition to the
  Witt theory was proposed by Henry Armstrong in 1888 and 1892. This
  assumed that all coloured substances were derivatives of ortho- or
  para-quinone (see QUINONES), and although at the time of its
  promotion little practical proof was given, yet the theory found wide
  acceptance on account of the researches of many other chemists. It
  follows on this theory that all coloured substances contain either of
  the groupings

         ____               ____
        /----\             /----\
       /      \           /      \
    ==<        >==  or   <        >== ,
       \______/           \\     /
        \____/             \\___/
                                \\

  the former being a para-quinonoid, the latter an ortho-quinonoid.
  While very many coloured substances must obviously contain this
  grouping, yet in many cases it is necessary to assume a simple
  intermolecular change, while in others a more complex rearrangement of
  bonds is necessary. Quinone, which is light yellow in colour, is the
  simplest coloured substance on this theory. Hydrocarbons of similar
  structure have been prepared by Thiele, for example, the orange-yellow
  tetraphenyl-_para_-xylylene, which is obtained by boiling the bromide
  C6H4[CBr(C6H5)2]2 with benzene and molecular silver. The quinonoid
  structure of many coloured compounds has been proved experimentally,
  as, for example, by Hewitt for the benzene-azo-phenols, and Hantzsch
  for triaminotriphenyl methane and acridine derivatives; but, at the
  same time, many substances cannot be so explained. A notable example
  is provided by the phthaleins, which result by the condensation of
  phthalic anhydride with phenols. In the free state these substances
  are colourless, and were assumed to have the formula shown in 1.
  Solution in dilute alkali was supposed to be accompanied by the
  rupture of the lactone ring with the formation of the quinonoid salt
  shown in 2.

        /\         /\         O   /\        /\
    HO /  \       /  \ OH      \\/  \      /  \ OH
      |    |     |    |         |    |    |    |
      |    |     |    |         |    |    |    |
       \  / \   / \  /           \  /\\  / \  /
        \/    C    \/             \/   C    \/
             / \                      /
         C6H<   >O               C6H4<
             \ /                      \
             CO                      COON3
             (1)                      (2)

  Baeyer (_Ber._, 1905, 38, p. 569) and Silberrad (_Journ. Chem. Soc._,
  1906, 89, p. 1787) have disputed the correctness of this explanation,
  and the latter has prepared melliteins and pyromelliteins, which are
  highly-coloured compounds produced from mellitic and pyromellitic
  acids, and which cannot be formulated as quinones. Baeyer has
  suggested that the nine carbon atom system of xanthone may act as a
  chromophore. An alternative view, due to Green, is that the oxygen
  atom of the xanthone ring is tetravalent, a supposition which permits
  the formulation of these substances as ortho-quinonoids.

  The theories of colour have also been investigated by Hantzsch, who
  first considered the nitro-phenols. On the chromophore-auxochrome
  theory (the nitro group being the chromophore, and the hydroxyl the
  auxochrome) it is necessary in order to explain the high colour of the
  metallic salts and the colourless alkyl and aryl derivatives to assume
  that the auxochromic action of the hydroxyl group is only brought
  strongly into evidence by salt formation. Armstrong, on the other
  hand, assumed an intermolecular change, thus:--

        /\                 /\
    HO /  \ OH            /  \ == O
      |    |      ===>   |    |
      |    |             |    |
       \  / NO2           \  / == NO2Na.
        \/                 \/

  The proof of this was left for Hantzsch, who traced a connexion with
  the nitrolic acids of V. Meyer, which are formed when nitrous acid
  acts on primary aliphatic nitro compounds. Meyer formulated these
  compounds as nitroximes or nitro-isnitroso derivatives, viz.
  R·C(NO2)(NOH). Hantzsch explains the transformation of the colourless
  acid into red salts, which on standing yield more stable, colourless
  salts, by the following scheme:--

                                N
           NOH                //  \                  NO2Na
         //               R·C       O             //
     R·C          ===>        \   /    ===>   R·C
         \\                     N                 \\
           NO2                //  \                  NO
                             O      ONa

   Colourless, stable.   Coloured, labile.    Colourless, stable

  He has also shown that the nitrophenols yield, in addition to the
  colourless true nitrophenol ethers, an isomeric series of coloured
  unstable quinonoid _aci_-ethers, which have practically the same
  colour and yield the same absorption spectra as the coloured metallic
  salts. He suggests that the term "quinone" theory be abandoned, and
  replaced by the _Umlagerungs_ theory, since this term implies some
  intermolecular rearrangement, and does not connote simply benzenoid
  compounds as does "quinonoid." H. von Liebig (_Ann._, 1908, 360, p.
  128), from a very complete discussion of triphenyl-methane
  derivatives, concluded that the grouping

    R R R
    Ä-Ä-Ä

  was the only true organic chromophore, colour production, however,
  requiring another condition, usually the closing of a ring.

The views as to the question of colour and constitution may be
summarized as follows:--(1) The quinone theory (Armstrong, Gomberg, R.
Meyer) regards all coloured substances as having a quinonoid structure.
(2) The chromophore-auxochrome theory (Kauffmann) regards colour as due
to the entry of an "auxochrome" into a "chromophoric" molecule. (3) If a
colourless compound gives a coloured one on solution or by
salt-formation, the production of colour may be explained as a
particular form of ionization (Baeyer), or by a molecular rearrangement
(Hantzsch). A dynamical theory due to E.C.C. Baly regards colour as due
to "isorropesis" or an oscillation between the residual affinities of
adjacent atoms composing the molecule.

_Fluorescence and Constitution._--The physical investigation of the
phenomenon named fluorescence--the property of transforming incident
light into light of different refrangibility--is treated in the article
FLUORESCENCE. Researches in synthetical organic chemistry have shown
that this property of fluorescence is common to an immense number of
substances, and theories have been proposed whose purpose is to connect
the property with constitution.

  In 1897 Richard Meyer (_Zeit. physik. Chemie_, 24, p. 468) submitted
  the view that fluorescence was due to the presence of certain
  "fluorophore" groups; such groupings are the pyrone ring and its
  congeners, the central rings in anthracene and acridine derivatives,
  and the paradiazine ring in safranines. A novel theory, proposed by
  J.T. Hewitt in 1900 (_Zeit. f. physik. Chemie_, 34, p. 1; _B.A.
  Report_, 1903, p. 628, and later papers in the _Journ. Chem. Soc._),
  regards the property as occasioned by internal vibrations within the
  molecule conditioned by a symmetrical double tautomerism, light of one
  wave-length being absorbed by one form, and emitted with a different
  wave-length by the other. This oscillation may be represented in the
  case of acridine and fluorescein as

          CH                CH                CH
     //\ //\ /\\       //\ /|\ /\\       //\ /\\ /\\
    |   |   ||  | ==> |  || | ||  | ==> |   ||  |   |
    |   |   ||  | <== |  || | ||  | <== |   ||  |   |,
     \\/ \\/ \//       \\/ \|/ \//       \\/ \// \//
          N                 N                 N

    O       O                 O                 O       O
     \\/ \ / \ / \OH   HO/ \ / \ / \OH     / \ / \ / \//
      |   |   |   | ==> |   |   |   | ==> |   |   |   |
      |   |   |   | <== |   |   |   | <== |   |   |   |
       \ / \\/ \ /       \ / \ / \ /       \ / \// \ /
            C                 C                 C
           /                 / \               /
      C6H4·COOH          C6H4   O         C6H4·COOH
                             \ /
                             CO

  This theory brings the property of fluorescence into relation
  with that of colour; the forms which cause fluorescence being the
  coloured modifications: ortho-quinonoid in the case of acridine,
  para-quinonoid in the case of fluorescein. H. Kauffmann (_Ber._, 1900,
  33, p. 1731; 1904, 35, p. 294; 1905, 38, p. 789; _Ann._, 1906, 344, p.
  30) suggested that the property is due to the presence of at least two
  groups. The first group, named the "luminophore," is such that when
  excited by suitable aetherial vibrations emits radiant energy; the
  other, named the "fluorogen," acts with the luminophore in some way or
  other to cause the fluorescence. This theory explains the fluorescence
  of anthranilic acid (o-aminobenzoic acid), by regarding the aniline
  residue as the luminophore, and the carboxyl group as the fluorogen,
  since, apparently, the introduction of the latter into the
  non-fluorescent aniline molecule involves the production of a
  fluorescent substance. Although the theories of Meyer and Hewitt do
  not explain (in their present form) the behaviour of anthranilic acid,
  yet Hewitt has shown that his theory goes far to explain the
  fluorescence of substances in which a double symmetrical tautomerism
  is possible. This tautomerism may be of a twofold nature:--(1) it may
  involve the mere oscillation of linkages, as in acridine; or (2) it
  may involve the oscillation of atoms, as in fluorescein. A theory of a
  physical nature, based primarily upon Sir J.J. Thomson's theory of
  corpuscles, has been proposed by J. de Kowalski (_Compt. rend._ 1907,
  144, p. 266). We may notice that ethyl oxalosuccinonitrile is the
  first case of a fluorescent aliphatic compound (see W. Wislicenus and
  P. Berg, _Ber._, 1908, 41, p. 3757).

_Capillarity and Surface Tension._--Reference should be made to the
article CAPILLARY ACTION for the general discussion of this phenomenon
of liquids. It is there shown that the surface tension of a liquid may
be calculated from its rise in a capillary tube by the formula [gamma] =
½rhs, where [gamma] is the surface tension per square centimetre, r the
radius of the tube, h the height of the liquid column, and s the
difference between the densities of the liquid and its vapour. At the
critical point liquid and vapour become identical, and, consequently, as
was pointed out by Frankenheim in 1841, the surface tension is zero at
the critical temperature.


    Relation to molecular weight.

  Mendeléeff endeavoured to obtain a connexion between surface energy
  and constitution; more successful were the investigations of Schiff,
  who found that the "molecular surface tension," which he defined as
  the surface tension divided by the molecular weight, is constant for
  isomers, and that two atoms of hydrogen were equal to one of carbon,
  three to one of oxygen, and seven to one of chlorine; but these ratios
  were by no means constant, and afforded practically no criteria as to
  the molecular weight of any substance.

  In 1886 R. Eötvös (_Wied. Ann._ 27, p. 452), assuming that two liquids
  may be compared when the ratios of the volumes of the liquids to the
  volumes of the saturated vapours are the same, deduced that
  [gamma]V^{2/3} (where [gamma] is the surface tension, and V the
  molecular volume of the liquid) causes all liquids to have the same
  temperature coefficients. This theorem was investigated by Sir W.
  Ramsay and J. Shields (_Journ. Chem. Soc._ 63, p. 1089; 65, p. 167),
  whose results have thrown considerable light on the subject of the
  molecular complexity of liquids. Ramsay and Shields suggested that
  there exists an equation for the surface energy of liquids, analogous
  to the volume-energy equation of gases, PV = RT. The relation they
  suspected to be of the form [gamma]S = KT, where K is a constant
  analogous to R, and S the surface containing one gramme-molecule,
  [gamma] and T being the surface tension and temperature respectively.
  Obviously equimolecular surfaces are given by (Mv)^{2/3}, where M is
  the molecular weight of the substance, for equimolecular volumes are
  Mv, and corresponding surfaces the two-thirds power of this. Hence S
  may be replaced by (Mv)^{2/3}. Ramsay and Shields found from
  investigations of the temperature coefficient of the surface energy
  that T in the equation [gamma](Mv)^{2/3} = KT must be counted
  downwards from the critical temperature T less about 6°. Their surface
  energy equation therefore assumes the form [gamma](Mv)^{2/3} = K([tau]
  - 6°). Now the value of K, [gamma] being measured in dynes and M being
  the molecular weight of the substance as a gas, is in general 2.121;
  this value is never exceeded, but in many cases it is less. This
  diminution implies an association of molecules, the surface containing
  fewer molecules than it is supposed to. Suppose the coefficient of
  association be n, i.e. n is the mean number of molecules which
  associate to form one molecule, then by the normal equation we have
  [gamma](Mnv)^{2/3} = 2.121([tau] - 6°); if the calculated constant be
  K1, then we have also [gamma](Mv)^{2/3} = K1([tau]-6°). By division we
  obtain n^{2/3} = 2.121/K1, or n = (2.121/K1)^{3/2} the coefficient of
  association being thus determined.

  The apparatus devised by Ramsay and Shields consisted of a capillary
  tube, on one end of which was blown a bulb provided with a minute
  hole. Attached to the bulb was a glass rod and then a tube containing
  iron wire. This tube was placed in an outer tube containing the liquid
  to be experimented with; the liquid is raised to its boiling-point,
  and then hermetically sealed. The whole is enclosed in a jacket
  connected with a boiler containing a liquid, the vapour of which
  serves to keep the inner tube at any desired temperature. The
  capillary tube can be raised or lowered at will by running a magnet
  outside the tube, and the heights of the columns are measured by a
  cathetometer or micrometer microscope.

  Normal values of K were given by nitrogen peroxide, N2O4, sulphur
  chloride, S2Cl2, silicon tetrachloride, SiCl4, phosphorus chloride,
  PCl3, phosphoryl chloride, POCl3, nickel carbonyl, Ni(CO)4, carbon
  disulphide, benzene, pyridine, ether, methyl propyl ketone;
  association characterized many hydroxylic compounds: for ethyl alcohol
  the factor of association was 2.74-2-43, for n-propyl alcohol
  2.86-2.72, acetic acid 3.62-2.77, acetone 1.26, water 3.81-2.32;
  phenol, nitric acid, sulphuric acid, nitroethane, and propionitril,
  also exhibit association.

_Crystalline Form and Composition._

The development of the theory of crystal structure, and the fundamental
principles on which is based the classification of crystal forms, are
treated in the article CRYSTALLOGRAPHY; in the same place will be found
an account of the doctrine of isomorphism, polymorphism and morphotropy.
Here we shall treat the latter subjects in more detail, viewed from the
standpoint of the chemist. Isomorphism may be defined as the existence
of two or more different substances in the same crystal form and
structure, polymorphism as the existence of the same substance in two or
more crystal modifications, and morphotropy (after P. von Groth) as the
change in crystal form due to alterations in the molecule of closely
(chemically) related substances. In order to permit a comparison of
crystal forms, from which we hope to gain an insight into the prevailing
molecular conditions, it is necessary that some unit of crystal
dimensions must be chosen. A crystal may be regarded as built up of
primitive parallelepipeda, the edges of which are in the ratio of the
crystallographic axes, and the angles the axial angles of the crystals.
To reduce these figures to a common standard, so that the volumes shall
contain equal numbers of molecules, the notion of molecular volumes is
introduced, the arbitrary values of the crystallographic axes (a, b, c)
being replaced by the topic parameters[18] ([chi],[psi],[omega]), which
are such that, combined with the axial angles, they enclose volumes
which contain equal numbers of molecules. The actual values of the topic
parameters can then readily be expressed in terms of the elements of the
crystals (the axial ratios and angles), the density, and the molecular
weight (see Groth, _Physikalische Krystallographie_, or _Chemical
Crystallography_).

_Polymorphism._--On the theory that crystal form and structure are the
result of the equilibrium between the atoms and molecules composing the
crystals, it is probable, _a priori_, that the same substance may possess
different equilibrium configurations of sufficient stability, under
favourable conditions, to form different crystal structures. Broadly
this phenomenon is termed polymorphism; however, it is necessary to
examine closely the diverse crystal modifications in order to determine
whether they are really of different symmetry, or whether twinning has
occasioned the apparent difference. In the article CRYSTALLOGRAPHY the
nature and behaviour of twinned crystals receives full treatment; here
it is sufficient to say that when the planes and axes of twinning are
planes and axes of symmetry, a twin would exhibit higher symmetry (but
remain in the same crystal system) than the primary crystal; and, also,
if a crystal approximates in its axial constants to a higher system,
mimetic twinning would increase the approximation, and the crystal would
be pseudo-symmetric.

In general, polysymmetric and polymorphous modifications suffer
transformation when submitted to variations in either temperature or
pressure, or both. The criterion whether a pseudo-symmetric form is a
true polymorph or not consists in the determination of the scalar
properties (e.g. density, specific heat, &c.) of the original and the
resulting modification, a change being in general recorded only when
polymorphism exists. Change of temperature usually suffices to determine
this, though in certain cases a variation in pressure is necessary; for
instance, sodium magnesium uranyl acetate, NaMg(UO2)3(C2H3O2)9·9H2O
shows no change in density unless the observations are conducted under a
considerable pressure. Although many pseudo-symmetric twins are
transformable into the simpler form, yet, in some cases, a true
polymorph results, the change being indicated, as before, by alterations
in scalar (as well as vector) properties.

  For example, boracite forms pseudo-cubic crystals which become truly
  cubic at 265°, with a distinct change in density; leucite behaves
  similarly at about 560°. Again, the pyroxenes, RSiO3 (R = Fe, Mg, Mn,
  &c.), assume the forms (1) monoclinic, sometimes twinned so as to
  become pseudo-rhombic; (2) rhombic, resulting from the pseudo-rhombic
  structure of (1) becoming ultramicroscopic; and (3) triclinic,
  distinctly different from (1) and (2); (1) and (2) are polysymmetric
  modifications, while (3) and the pair (1) and (2) are polymorphs.

While polysymmetry is solely conditioned by the manner in which the
mimetic twin is built up from the single crystals, there being no change
in the scalar properties, and the vector properties being calculable
from the nature of the twinning, in the case of polymorphism entirely
different structures present themselves, both scalar and vector
properties being altered; and, in the present state of our knowledge, it
is impossible to foretell the characters of a polymorphous modification.
We may conclude that in polymorphs the substance occurs in different
phases (or molecular aggregations), and the equilibrium between these
phases follows definite laws, being dependent upon temperature and
pressure, and amenable to thermodynamic treatment (cf. CHEMICAL ACTION
and ENERGETICS). The transformation of polymorphs presents certain
analogies to the solidification of a liquid. Liquids may be cooled below
their freezing-point without solidification, the _metastable_ (after W.
Ostwald) form so obtained being immediately solidified on the
introduction of a particle of the solid modification; and supersaturated
solutions behave in a similar manner. At the same time there may be
conditions of temperature and pressure at which polymorphs may exist
side by side.

  The above may be illustrated by considering the equilibrium between
  rhombic and monoclinic sulphur. The former, which is deposited from
  solutions, is transformed into monoclinic sulphur at about 96°, but
  with great care it is possible to overheat it and even to fuse it (at
  113.5°) without effecting the transformation. Monoclinic sulphur,
  obtained by crystallizing fused sulphur, melts at 119.5°, and admits
  of undercooling even to ordinary temperatures, but contact with a
  fragment of the rhombic modification spontaneously brings about the
  transformation. From Reicher's determinations, the exact transition
  point is 95.6°; it rises with increasing pressure about 0.05° for one
  atmosphere; the density of the rhombic form is greater than that of
  the monoclinic. The equilibria of these modifications may be readily
  represented on a pressure-temperature diagram. If OT, OP (fig. 6), be
  the axes of temperature and pressure, and A corresponds to the
  transition point (95.6°) of rhombic sulphur, we may follow out the
  line AB which shows the elevation of the transition point with
  increasing pressure. The overheating curve of rhombic sulphur extends
  along the curve AC, where C is the melting-point of monoclinic
  sulphur. The line BC, representing the equilibrium between monoclinic
  and liquid sulphur, is thermodynamically calculable; the point B is
  found to correspond to 131° and 400 atmospheres. From B the curve of
  equilibrium (BD) between rhombic and liquid sulphur proceeds; and from
  C (along CE) the curve of equilibrium between liquid sulphur and
  sulphur vapour. Of especial interest is the curve BD: along this line
  liquid and rhombic sulphur are in equilibrium, which means that at
  above 131° and 400 atmospheres the rhombic (and not the monoclinic)
  variety would separate from liquid sulphur.

     | P               |D
     |                 |
     |               B |
     |                / \
     |               /   \    Liquid
     |              /     \
     |  Rhombic    /       \
     |            /         \          E
     |           /           \      _  -
     |          / Monoclinic_ \ -
     |         /     _   -     C
     |        /_  -
     |       /A
     |     /     Vapour
     |   /
     |/
     +----------------------------------
    O                                  T
                    FIG. 6.

  Mercuric iodide also exhibits dimorphism. When precipitated from
  solutions it forms red tetragonal crystals, which, on careful heating,
  give a yellow rhombic form, also obtained by crystallization from the
  fused substance, or by sublimation. The transition point is 126.3° (W.
  Schwarz, _Zeit. f. Kryst._ 25, p. 613), but both modifications may
  exist in metastable forms at higher and lower temperatures
  respectively; the rhombic form may be cooled down to ordinary
  temperature without changing, the transformation, however, being
  readily induced by a trace of the red modification, or by friction.
  The density and specific heat of the tetragonal form are greater than
  those of the yellow.

  Hexachlorethane is trimorphous, forming rhombic, triclinic and cubic
  crystals; the successive changes occur at about 44° and 71°, and are
  attended by a decrease in density.

  Tetramorphism is exhibited by ammonium nitrate. According to O.
  Lehmann it melts at 168° (or at a slightly lower temperature in its
  water of crystallization) and on cooling forms optically isotropic
  crystals; at 125.6° the mass becomes doubly refracting, and from a
  solution rhombohedral (optically uniaxial) crystals are deposited; by
  further cooling acicular rhombic crystals are produced at 82.8°, and
  at 32.4° other rhombic forms are obtained, identical with the product
  obtained by crystallizing at ordinary temperatures. The reverse series
  of transformations occurs when this final modification is heated. M.
  Bellati and R. Romanese (_Zeit. f. Kryst._ 14, p. 78) determined the
  densities and specific heats of these modifications. The first and
  third transformations (reckoned in order with increasing temperature
  of the transition point) are attended by an increase in volume, the
  second with a contraction; the solubility follows the same direction,
  increasing up to 82.8°, then diminishing up to 125.6°, and then
  increasing from this temperature upwards.

The physical conditions under which polymorphous modifications are
prepared control the form which the substance assumes. We have already
seen that temperature and pressure exercise considerable influence in
this direction. In the case of separation from solutions, either by
crystallization or by precipitation by double decomposition, the
temperature, the concentration of the solution, and the presence of
other ions may modify the form obtained. In the case of sodium
dihydrogen phosphate, NaH2PO4·H2O, a stable rhombic form is obtained
from warm solutions, while a different, unstable, rhombic form is
obtained from cold solutions. Calcium carbonate separates as hexagonal
calcite from cold solutions (below 30°), and as rhombic aragonite from
solutions at higher temperatures; lead and strontium carbonates,
however, induce the separation of aragonite at lower temperatures. From
supersaturated solutions the form unstable at the temperature of the
experiment is, as a rule, separated, especially on the introduction of a
crystal of the unstable form; and, in some cases, similar inoculation of
the fused substance is attended by the same result. Different
modifications may separate and exist side by side at one and the same
time from a solution; e.g. telluric acid forms cubic and monoclinic
crystals from a hot nitric acid solution, and ammonium fluosilicate
gives cubic and hexagonal forms from aqueous solutions between 6° and
13°.

A comparison of the transformation of polymorphs leads to a twofold
classification: (1) polymorphs directly convertible in a reversible
manner--termed "enantiotropic" by O. Lehmann and (2) polymorphs in which
the transformation proceeds in one direction only--termed "monotropic."
In the first class are included sulphur and ammonium nitrate; monotropy
is exhibited by aragonite and calcite.

It is doubtful indeed whether any general conclusions can yet be drawn
as to the relations between crystal structure and scalar properties and
the relative stability of polymorphs. As a general rule the modification
stable at higher temperatures possesses a lower density; but this is by
no means always the case, since the converse is true for antimonious and
arsenious oxides, silver iodide and some other substances. Attempts to
connect a change of symmetry with stability show equally a lack of
generality. It is remarkable that a great many polymorphous substances
assume more symmetrical forms at higher temperatures, and a possible
explanation of the increase in density of such compounds as silver
iodide, &c., may be sought for in the theory that the formation of a
more symmetrical configuration would involve a drawing together of the
molecules, and consequently an increase in density. The insufficiency of
this argument, however, is shown by the data for arsenious and
antimonious oxides, and also for the polymorphs of calcium carbonate,
the more symmetrical polymorphs having a lower density.

_Morphotropy._--Many instances have been recorded where substitution has
effected a deformation in one particular direction, the crystals of
homologous compounds often exhibiting the same angles between faces
situated in certain zones. The observations of Slavik (_Zeit. f.
Kryst._, 1902, 36, p. 268) on ammonium and the quaternary ammonium
iodides, of J.A. Le Bel and A. Ries (_Zeit. f. Kryst._, 1902, 1904, et
seq.) on the substituted ammonium chlorplatinates, and of G. Mez (ibid.,
1901, 35, p. 242) on substituted ureas, illustrate this point.

  Ammonium iodide assumes cubic forms with perfect cubic cleavage;
  tetramethyl ammonium iodide is tetragonal with perfect cleavages
  parallel to {100} and {001}--a difference due to the lengthening of
  the a axes; tetraethyl ammonium iodide also assumes tetragonal forms,
  but does not exhibit the cleavage of the tetramethyl compound; while
  tetrapropyl ammonium iodide crystallizes in rhombic form. The
  equivalent volumes and topic parameters are tabulated:

    +---------+----------+------------+-----------+----------+
    |         |   NH4I.  |   NMe4I.   |   NEt4I.  |  NPr4I.  |
    +---------+----------+------------+-----------+----------+
    |   V     |  57.51   |  108.70    |  162.91   | 235.95   |
    | [chi]   |   3.860  |    5.319   |    6.648  |   6.093  |
    | [psi]   |   3.860  |    5.319   |    6.648  |   7.851  |
    | [omega] |   3.860  |    3.842   |    3.686  |   4.933  |
    +---------+----------+------------+-----------+----------+

  From these figures it is obvious that the first three compounds form a
  morphotropic series; the equivalent volumes exhibit a regular
  progression; the values of [chi] and [psi], corresponding to the a
  axes, are regularly increased, while the value of [omega],
  corresponding to the c axis, remains practically unchanged. This
  points to the conclusion that substitution has been effected in one of
  the cube faces. We may therefore regard the nitrogen atoms as
  occupying the centres of a cubic space lattice composed of iodine
  atoms, between which the hydrogen atoms are distributed on the
  tetrahedron face normals. Coplanar substitution in four hydrogen atoms
  would involve the pushing apart of the iodine atoms in four horizontal
  directions. The magnitude of this separation would obviously depend on
  the magnitude of the substituent group, which may be so large (in this
  case propyl is sufficient) as to cause unequal horizontal deformation
  and at the same time a change in the vertical direction.

The measure of the loss of symmetry associated with the introduction of
alkyl groups depends upon the relative magnitudes of the substituent
group and the rest of the molecule; and the larger the molecule, the
less would be the morphotropic effect of any particular substituent. The
mere retention of the same crystal form by homologous substances is not
a sufficient reason for denying a morphotropic effect to the substituent
group; for, in the case of certain substances crystallizing in the cubic
system, although the crystal form remains unaltered, yet the structures
vary. When both the crystal form and structure are retained, the
substances are said to be isomorphous.

Other substituent groups exercise morphotropic effects similar to those
exhibited by the alkyl radicles; investigations have been made on
halogen-, hydroxy-, and nitro-derivatives of benzene and substituted
benzenes. To Jaeger is due the determination of the topic parameters of
certain haloid-derivatives, and, while showing that the morphotropic
effects closely resemble those occasioned by methyl, he established the
important fact that, in general, the crystal form depended upon the
orientation of the substituents in the benzene complex.

  Benzoic acid is pseudo-tetragonal, the principal axis being remarkably
  long; there is no cleavage at right angles to this axis. Direct
  nitration gives (principally) m-nitrobenzoic acid, also
  pseudo-tetragonal with a much shorter principal axis. From this two
  chlornitrobenzoic acids [COOH·NO2·Cl = 1.3.6 and 1.3.4] may be
  obtained. These are also pseudotetragonal; the (1.3.6) acid has nearly
  the same values of [chi] and [psi] as benzoic acid, but [omega] is
  increased; compared with m-nitrobenzoic acid, [chi] and [psi] have
  been diminished, whereas [omega] is much increased; the (1.3.4) acid
  is more closely related to m-nitrobenzoic acid, [chi] and [psi] being
  increased, [omega] diminished. The results obtained for the (1.2) and
  (1.4) chlorbenzoic acids also illustrate the dependence of crystal
  form and structure on the orientation of the molecule.

  The hydroxyl group also resembles the methyl group in its morphotropic
  effects, producing, in many cases, no change in symmetry but a
  dimensional increase in one direction. This holds for benzene and
  phenol, and is supported by the observations of Gossner on [1.3.5]
  trinitrobenzene and picric acid (1.3.5-trinitro, 2 oxybenzene); these
  last two substances assume rhombic forms, and picric acid differs from
  trinitrobenzene in having [omega] considerably greater, with [chi] and
  [psi] slightly less. A similar change, in one direction only,
  characterizes benzoic acid and salicylic acid.

  The nitro group behaves very similarly to the hydroxyl group. The
  effect of varying the position of the nitro group in the molecule is
  well marked, and conclusions may be drawn as to the orientation of the
  groups from a knowledge of the crystal form; a change in the symmetry
  of the chemical molecule being often attended by a loss in the
  symmetry of the crystal.

It may be generally concluded that the substitution of alkyl, nitro,
hydroxyl, and haloid groups for hydrogen in a molecule occasions a
deformation of crystal structure in one definite direction, hence
permitting inferences as to the configuration of the atoms composing the
crystal; while the nature and degree of the alteration depends (1) upon
the crystal structure of the unsubstituted compound; (2) on the nature
of the substituting radicle; (3) on the complexity of the substituted
molecule; and (4) on the orientation of the substitution derivative.

_Isomorphism._--It has been shown that certain elements and groups
exercise morphotropic effects when substituted in a compound; it may
happen that the effects due to two or more groups are nearly equivalent,
and consequently the resulting crystal forms are nearly identical. This
phenomenon was first noticed in 1822 by E. Mitscherlich, in the case of
the acid phosphate and acid arsenate of potassium, KH2P(As)O4, who
adopted the term isomorphism, and regarded phosphorus and arsenic as
isomorphously related elements. Other isomorphously related elements and
groups were soon perceived, and it has been shown that elements so
related are also related chemically.

  Tutton's investigations of the morphotropic effects of the metals
  potassium, rubidium and caesium, in combination with the acid radicals
  of sulphuric and selenic acids, showed that the replacement of
  potassium by rubidium, and this metal in turn by caesium, was
  accompanied by progressive changes in both physical and
  crystallographical properties, such that the rubidium salt was always
  intermediate between the salts of potassium and caesium (see table;
  the space unit is taken as a pseudo-hexagonal prism). This fact finds
  a parallel in the atomic weights of these metals.

    +---------+---------+---------+---------+---------+
    |         |    V    |  [chi]  |  [psi]  | [omega] |
    +---------+---------+---------+---------+---------+
    | K2SO4   |  69.42  |  4.464  |  4.491  |  4.997  |
    | Rb2SO4  |  73.36  |  4.634  |  4.664  |  5.237  |
    | Cs2SO4  |  83.64  |  4.846  |  4.885  |  5.519  |
    +---------+---------+---------+---------+---------+
    | K2SeO4  |  71.71  |  4.636  |  4.662  |  5.118  |
    | Rb2SeO4 |  79.95  |  4.785  |  4.826  |  5.346  |
    | Cs2SeO4 |  91.16  |  4.987  |  5.035  |  5.697  |
    +---------+---------+---------+---------+---------+

  By taking appropriate differences the following facts will be
  observed: (1) the replacement of potassium by rubidium occasions an
  increase in the equivalent volumes by about eight units, and of
  rubidium by caesium by about eleven units; (2) replacement in the same
  order is attended by a general increase in the three topic parameters,
  a greater increase being met with in the replacement of rubidium by
  caesium; (3) the parameters [chi] and [psi] are about equally
  increased, while the increase in [omega] is always the greatest. Now
  consider the effect of replacing sulphur by selenium. It will be seen
  that (1) the increase in equivalent volume is about 6.6; (2) all the
  topic parameters are increased; (3) the greatest increase is effected
  in the parameters [chi] and [psi], which are equally lengthened.

  These observations admit of ready explanation in the following
  manner. The ordinary structural formula of potassium sulphate is

          O
          |
    K--O--S--O--K.
          |
          O

  If the crystal structure be regarded as composed of three
  interpenetrating point systems, one consisting of sulphur atoms, the
  second of four times as many oxygen atoms, and the third of twice as
  many potassium atoms, the systems being so arranged that the sulphur
  system is always centrally situated with respect to the other two, and
  the potassium system so that it would affect the vertical axis, then
  it is obvious that the replacement of potassium by an element of
  greater atomic weight would specially increase the length of [omega]
  (corresponding to the vertical axis), and cause a smaller increase in
  the horizontal parameters [chi] and [psi]; moreover, the increments
  would advance with the atomic weight of the replacing metal. If, on
  the other hand, the sulphur system be replaced by a corresponding
  selenium system, an element of higher atomic weight, it would be
  expected that a slight increase would be observed in the vertical
  parameter, and a greater increase recorded equally in the horizontal
  parameters.

  Muthmann (_Zeit. f. Kryst._, 1894), in his researches on the tetragonal
  potassium and ammonium dihydrogen phosphates and arsenates, found that
  the replacement of potassium by ammonium was attended by an increase
  of about six units in the molecular volume, and of phosphorus by
  arsenic by about 4.6 units. In the topic parameters the following
  changes were recorded: replacement of potassium by ammonium was
  attended by a considerable increase in [omega], [chi] and [psi] being
  equally, but only slightly, increased; replacement of phosphorus by
  arsenic was attended by a considerable increase, equally in [chi] and
  [psi], while [omega] suffered a smaller, but not inconsiderable,
  increase. It is thus seen that the ordinary plane representation of
  the structure of compounds possesses a higher significance than could
  have been suggested prior to crystallographical researches.

Identity, or approximate identity, of crystal form is not in itself
sufficient to establish true isomorphism. If a substance deposits itself
on the faces of a crystal of another substance of similar crystal form,
the substances are probably isomorphous. Such parallel overgrowths,
termed episomorphs, are very common among the potassium and sodium
felspars; and K. von Hauer has investigated a number of cases in which
salts exhibiting episomorphism have different colours, thereby clearly
demonstrating this property of isomorphism. For example, episomorphs of
white potash alum and violet chrome alum, of white magnesium sulphate
and green nickel sulphate, and of many other pairs of salts, have been
obtained. More useful is the property of isomorphous substances of
forming mixed crystals, which are strictly isomorphous with their
constituents, for all variations in composition. In such crystals each
component plays its own part in determining the physical properties; in
other words, any physical constant of a mixed crystal can be calculated
as additively composed of the constants of the two components.

  [Illustration: FIG. 7.]

  [Illustration: FIG. 8.]

  Fig. 7 represents the specific volumes of mixtures of ammonium and
  potassium sulphates; the ordinates representing specific volumes, and
  the abscissae the percentage composition of the mixture. Fig. 8 shows
  the variation of refractive index of mixed crystals of potash alum and
  thallium alum with variation in composition.

  In these two instances the component crystals are miscible in all
  proportions; but this is by no means always the case. It may happen
  that the crystals do not form double salts, and are only miscible in
  certain proportions. Two cases then arise: (1) the properties may be
  expressed as linear functions of the composition, the terminal values
  being identical with those obtained for the individual components, and
  there being a break in the curve corresponding to the absence of mixed
  crystals; or (2) similar to (1) except that different values must be
  assigned to the terminal values in order to preserve collinearity.
  Fig. 9 illustrates the first case: the ordinates represent specific
  volumes, and the abscissae denote the composition of isomorphous
  mixtures of ammonium and potassium dihydrogen phosphates, which
  mutually take one another up to the extent of 20% to form homogeneous
  crystals. The second case is illustrated in fig. 10. Magnesium
  sulphate (orthorhombic) takes up ferrous sulphate (monoclinic) to the
  extent of 19%, forming isomorphous orthorhombic crystals; ferrous
  sulphate, on the other hand, takes up magnesium sulphate to the extent
  of 54% to form monoclinic crystals. By plotting the specific volumes
  of these mixed crystals as ordinates, it is found that they fall on
  two lines, the upper corresponding to the orthorhombic crystals, the
  lower to the monoclinic. From this we may conclude that these salts
  are isodimorphous: the upper line represents isomorphous crystals of
  stable orthorhombic magnesium sulphate and unstable orthorhombic
  ferrous sulphate, the lower line isomorphous crystals of stable
  monoclinic ferrous sulphate and unstable monoclinic magnesium
  sulphate.

  [Illustration: FIG. 9.]

  [Illustration: FIG. 10.]

  An important distinction separates true mixed crystals and
  crystallized double salts, for in the latter the properties are not
  linear functions of the properties of the components; generally there
  is a contraction in volume, while the refractive indices and other
  physical properties do not, in general, obey the additive law.

Isomorphism is most clearly discerned between elements of analogous
chemical properties; and from the wide generality of such observations
attempts have been made to form a classification of elements based on
isomorphous replacements. The following table shows where isomorphism
may be generally expected. The elements are arranged in eleven series,
and the series are subdivided (as indicated by semicolons) into groups;
these groups exhibit partial isomorphism with the other groups of the
same series (see W. Nernst, _Theoretical Chemistry_).

    Series 1. Cl, Br, I, F; Mn (in permanganates).
           2. S, Se; Te (in tellurides); Cr, Mn, Te (in the acids
                H2RO4); As, Sb (in the glances MR2).
           3. As, Sb, Bi; Te (as an element); P, Vd (in salts); N,
                P (in organic bases).
           4. K, Na, Cs, Rb, Li; Tl, Ag.
           5. Ca, Ba, Sr, Pb; Fe, Zn, Mn, Mg; Ni, Co, Cu; Ce, La,
                Di, Er, Y, Ca; Cu, Hg, Pb; Cd, Be, In, Zn; Tl, Pb.
           6. Al, Fe, Cr, Mn; Ce, U (in sesquioxides).
           7. Cu, Ag (when monovalent); Au.
           8. Pt, Ir, Pd, Rh, Ru, Os; Au, Fe, Ni; Sn, Te.
           9. C, Si, Ti, Zr, Th, Sn; Fe, Ti.
          10. Ta, Cb (Nb).
          11. Mo, W, Cr.

  For a detailed comparison of the isomorphous relations of the elements
  the reader is referred to P. von Groth, _Chemical Crystallography_.
  Reference may also be made to Ida Freund, _The Study of Chemical
  Composition_; and to the _Annual Reports of the Chemical Society_ for
  1908, p. 258.

  BIBLIOGRAPHY.--_History_: F. Hoefer, _Histoire de la chimie_ (2nd ed.,
  1866-1869); Hermann Kopp, _Geschichte der Chemie_ (1869),
  _Entwickelung der Chemie in d. neueren Zeit_ (1871-1874); E. von
  Meyer, _Geschichte der Chemie_ (3rd ed., 1905, Eng. trans.); A.
  Ladenburg, _Entwickelungsgeschichte der Chemie_ (4th ed., 1907); A.
  Stange, _Die Zeitalter der Chemie_ (1908). Reference may also be made
  to M.M. Pattison Muir, _History of Chemical Theories and Laws_ (1907);
  Ida Freund, _Study of Chemical Composition_ (1904); T.E. Thorpe,
  _Essays in Historical Chemistry_ (2nd ed., 1902). See also the article
  ALCHEMY.

  _Principles and Physical._--W. Ostwald, _Principles of Inorganic
  Chemistry_ (3rd Eng. ed., 1908), _Outlines of General Chemistry_,
  _Lehrbuch der allgemeinen Chemie_; W. Nernst, _Theoretische Chemie_
  (4th ed., 1907, Eng. trans.); J.H. van't Hoff, _Lectures on
  Theoretical and Physical Chemistry_; J. Walker, _Introduction to
  Physical Chemistry_ (4th ed., 1907); H.C. Jones, _Outlines of Physical
  Chemistry_ (1903); D. Mendeléeff, _Principles of Chemistry_ (3rd ed.,
  1905).

  _Inorganic._--Roscoe and Schorlemmer, _Inorganic Chemistry_ (3rd ed.,
  Non-metals, 1905; Metals, 1907); R. Abegg, _Handbuch der anorganischen
  Chemie_; Gmelin-Kraut, _Handbuch der anorganischen Chemie_; O. Dammer,
  _Handbuch der anorganischen Chemie_; H. Moissan, _Chimie minérale_.

  _Organic._--F. Beilstein, _Handbuch der organischen Chemie_; M.M.
  Richter, _Lexikon der Kohlenstoffverbindungen_ (these are primarily
  works of reference); V. Meyer and P.H. Jacobson, _Lehrbuch der
  organischen Chemie_; Richter-Anschutz, _Organische Chemie_ (11th ed.,
  vol. i., 1909, Eng. trans.); G.K. Schmidt, _Kurzes Lehrbuch der
  organischen Chemie_; A. Bernthsen, _Organische Chemie_ (Eng. trans.).
  Practical methods are treated in Lassar-Cohn, _Arbeitsmethoden für
  organisch-chemische Laboratorien_ (4th ed., 1906-1907). Select
  chapters are treated in A. Lachmann, _Spirit of Organic Chemistry_;
  J.B. Cohen, _Organic Chemistry_ (1908); A.W. Stewart, _Recent Advances
  in Organic Chemistry_ (1908); and in a series of pamphlets issued
  since 1896 with the title _Sammlung chemischer und
  chemisch-technischer Vorträge._

  _Analytical._--For Blowpipe Analysis: C.F. Plattner, _Probirkunst mit
  dem Löthrohr_. For General Analysis: C.R. Fresenius, _Qualitative and
  Quantitative Analysis_, Eng. trans, by C.E. Groves (_Qualitative_,
  1887) and A.I. Cohn (_Quantitative_, 1903); F.P. Treadwell, _Kurzes
  Lehrbuch der analytischen Chemie_ (1905); F. Julian, _Textbook of
  Quantitative Chemical Analysis_ (1904); A. Classen, _Ausgewählte
  Methoden der analytischen Chemie_ (1901-1903); W. Crookes, _Select
  Methods in Chemical Analysis_ (1894). Volumetric Analysis: F. Sutton,
  _Systematic Handbook of Volumetric Analysis_ (1904); F. Mohr,
  _Lehrbuch der chemisch-analytischen Titrirmethode_ (1896). Organic
  Analysis: Hans Meyer, _Analyse und Konstitutionsermittlung organischer
  Verbindungen_ (1909); Wilhelm Vaubel, _Die physikalischen und
  chemischen Methoden der quantitativen Bestimmung organischer
  Verbindungen_. For the historical development of the proximate
  analysis of organic compounds see M.E.H. Dennstedt, _Die Entwickelung
  der organischen Elementaranalyse_ (1899).

  _Encyclopaedias._--The early dictionaries of Muspratt and Watts are
  out of date; there is a later edition of the latter by H.F. Morley and
  M.M.P. Muir. A. Ladenburg, _Handwörterbuch der Chemie_, A. Wurtz,
  _Dictionnaire de chimie_, and F. Selmi, _Enciclopedia di chimica_, are
  more valuable; the latter two are kept up to date by annual
  supplements.     (C. E.*)


FOOTNOTES:

  [1] The more notable chemists of this period were Turquet de Mayerne
    (1573-1665), a physician of Paris, who rejected the Galenian
    doctrines and accepted the exaggerations of Paracelsus; Andreas
    Libavius (d. 1616), chiefly famous for his _Opera Omnia
    Medicochymica_ (1595); Jean Baptiste van Helmont (1577-1644),
    celebrated for his researches on gases; F. de la Boë Sylvius
    (1614-1672), who regarded medicine as applied chemistry; and Otto
    Tachenius, who elucidated the nature of salts.

  [2] This dictum was questioned by the researches of H. Landolt, A.
    Heydweiller and others. In a series of 75 reactions it was found
    that in 61 there was apparently a diminution in weight, but in 1908,
    after a most careful repetition and making allowance for all
    experimental errors, Landolt concluded that no change occurred (see
    ELEMENT).

  [3] The theory of Berthollet was essentially mechanical, and he
    attempted to prove that the course of a reaction depended not on
    affinities alone but also on the masses of the reacting components.
    In this respect his hypothesis has much in common with the "law of
    mass-action" developed at a much later date by the Swedish chemists
    Guldberg and Waage, and the American, Willard Gibbs (see CHEMICAL
    ACTION). In his classical thesis Berthollet vigorously attacked the
    results deduced by Bergman, who had followed in his table of
    elective attractions the path traversed by Stahl and S. F. Geoffroy.

  [4] Dalton's atomic theory is treated in more detail in the article
    ATOM.

  [5] Berzelius, however, appreciated the necessity of differentiating
    the atom and the molecule, and even urged Dalton to amend his
    doctrine, but without success.

  [6] The following symbols were also used by Bergman:--

    [Illustration]

    which represented zinc, manganese, cobalt, bismuth, nickel, arsenic,
    platinum, water, alcohol, phlogiston.

  [7] The following are the symbols employed by Dalton:--

    [Illustration]

    which represent in order, hydrogen, nitrogen, carbon, oxygen,
    phosphorus, sulphur, magnesia, lime, soda, potash, strontia, baryta,
    mercury; iron, zinc, copper, lead, silver, platinum, and gold were
    represented by circles enclosing the initial letter of the element.

  [8] Approximate values of the atomic weights are employed here.

  [9] The definite distinction between potash and soda was first
    established by Duhamel de Monceau (1700-1781).

  [10] The reader is specially referred to the articles ALIZARIN;
    INDIGO; PURIN and TERPENES for illustrations of the manner in which
    chemists have artificially prepared important animal and vegetable
    products.

  [11] These observations were generalized by J.B. Dumas and Polydore
    Boullay (1806-1835) in their "etherin theory" (_vide infra_).

  [12] This must not be confused with the modern _acetyl_, CH3·CO, which
    at that time was known as _acetoxyl_.

  [13] It is now established that ortho compounds do exist in isomeric
    forms, instances being provided by chlor-, brom-, and amino-toluene,
    chlorphenol, and chloraniline; but arguments, e.g. E. Knoevenagel's
    theory of "motoisomerism," have been brought forward to cause these
    facts to support Kekulé.

  [14] Victor Meyer and G. Heyl (_Ber._, 1895, 28, p. 2776) attempted a
    solution from the following data. It is well known that
    di-ortho-substituted benzoic acids are esterified with difficulty.
    Two acids corresponding to the formula of Kekulé and Claus are
    triphenyl acrylic acid, (C6H5)2C:C(COOH)·C6H5, and triphenyl acetic
    acid, (C6H5)3C·COOH. Experiments showed that the second acid was
    much more difficult to esterify than the first, pointing to the
    conclusion that Claus' formula for benzene was more probable than
    Kekulé's.

  [15] H. Rose, _Ausführliches Handbuch der analytischen Chemie_ (1851).

  [16] F. Wöhler, _Die Mineralanalyse in Beispielen_ (1861).

  [17] For the connexion between valency and volume, see VALENCY.

  [18] This was done simultaneously in 1894 by W. Muthmann and A. E.
    H. Tutton, the latter receiving the idea from F. Becke (see _Journ.
    Chem. Soc._, 1896, 69, p. 507; 1905, 87, p. 1183).



CHEMNITZ (or KEMNITZ), MARTIN (1522-1586), German Lutheran theologian,
third son of Paul Kemnitz, a cloth-worker of noble extraction, was born
at Treuenbrietzen, Brandenburg, on the 9th of November 1522. Left an
orphan at the age of eleven, he worked for a time at his father's trade.
A relative at Magdeburg put him to school there (1539-1542). Having made
a little money by teaching, he went (1543) to the university of
Frankfort-on-Oder; thence (1545) to that of Wittenberg. Here he heard
Luther preach, but was more attracted by Melanchthon, who interested him
in mathematics and astrology. Melanchthon gave him (1547) an
introduction to his son-in-law, Georg Sabinus, at Königsberg, where he
was tutor to some Polish youths, and rector (1548) of the Kneiphof
school. He practised astrology; this recommended him to Duke Albert of
Prussia, who made him his librarian (1550). He then turned to Biblical,
patristic and kindred studies. His powers were first brought out in
controversy with Osiander on justification by faith. Osiander,
maintaining the infusion of Christ's righteousness into the believer,
impugned the Lutheran doctrine of imputation; Chemnitz defended it with
striking ability. As Duke Albert sided with Osiander, Chemnitz resigned
the librarianship. Returning (1553) to Wittenberg, he lectured on
Melanchthon's _Loci Communes_, his lectures forming the basis of his own
_Loci Theologici_ (published posthumously, 1591), which constitute
probably the best exposition of Lutheran theology as formulated and
modified by Melanchthon. His lectures were thronged, and a university
career of great influence lay before him, when he accepted a call to
become coadjutor at Brunswick to the superintendent, Joachim Mörlin, who
had known him at Königsberg. He removed to Brunswick on the 15th of
December 1554, and there spent the remainder of his life, refusing
subsequent offers of important offices from various Protestant princes
of Germany. Zealous in the duties of his pastoral charge, he took a
leading part in theological controversy. His personal influence, at a
critical period, did much to secure strictness of doctrine and
compactness of organization in the Lutheran Church. Against
Crypto-Calvinists he upheld the Lutheran view of the eucharist in his
_Repetitio sanae doctrinae de Vera Praesentia_ (1560; in German, 1561).
To check the reaction towards the old religion he wrote several works of
great power, especially his _Theologiae Jesuitarum praecipua capita_
(1562), an incisive attack on the principles of the society, and the
_Examen concilii Tridentini_ (four parts, 1565-66-72-73), his greatest
work. His _Corpus doctrinae Prutenicum_ (1567), drawn up in conjunction
with Mörlin, at once acquired great authority. In the year of its
publication he became superintendent of Brunswick, and in effect the
director of his church throughout Lower Saxony. His tact was equal to
his learning. In conjunction with Andreä and Selnecker he induced the
Lutherans of Saxony and Swabia to adopt the _Formula Concordiae_ and so
become one body. Against lax views of Socinian tendency he directed his
able treatise _De duabus naluris in Christo_ (1570). Resigning office in
infirm health (1584) he survived till the 8th of April 1586.

  Lives of Chemnitz are numerous, e.g. by T. Gasmerus (1588), T. Pressel
  (1862), C.G.H. Lentz (1866), H. Hachfeld (1867), H. Schmid in J.J.
  Herzog's _Realencyklopädie_ (1878), T. Kunze in A. Hauck's
  _Realencyklop. für prot. Theol. und Kirche_ (1897); that by Hausle, in
  I. Goschler's _Dict. encyclopédique de la théol. cath._ (1858), gives
  a Roman Catholic view.       (A. Go.*)



CHEMNITZ, a town of Germany, in the kingdom of Saxony, the capital of a
governmental district, 50 m. W.S.W. of Dresden and 51 S.E. of Leipzig by
rail. Pop. (1885) 110,817; (1895) 161,017; (1905) 244,405. It lies 950
ft. above the sea, in a fertile plain at the foot of the Erzgebirge,
watered by the river Chemnitz, an affluent of the Mulde. It is the chief
manufacturing town in the kingdom, ranks next to Dresden and Leipzig in
point of population, and is one of the principal commercial and
industrial centres of Germany. It is well provided with railway
communication, being directly connected with Berlin and with the
populous and thriving towns of the Erzgebirge and Voigtland. Chemnitz is
in general well built, the enormous development of its industry and
commerce having of late years led to the laying out of many fine streets
and to the embellishing of the town with handsome buildings. The centre
is occupied by the market square, with the handsome medieval Rathaus,
now superseded for municipal business by a modern building in the
Post-strasse. In this square are monuments to the emperor William I.,
Bismarck and Moltke. The old inner town is surrounded by pleasant
promenades, occupying the site of the old fortifications, and it is
beyond these that industrial Chemnitz lies, girdling the old town on all
sides with a thick belt of streets and factories, and ramifying far into
the country. Chemnitz has eleven Protestant churches, among them the
ancient Gothic church of St James, with a fine porch, and the modern
churches of St Peter, St Nicholas and St Mark. There are also a
synagogue and chapels of various sects. The industry of Chemnitz has
gained for the town the name of "Saxon Manchester." First in importance
are its locomotive and engineering works, which give employment to some
20,000 hands in 90 factories. Next come its cotton-spinning, hosiery,
textile and glove manufactures, in which a large trade is done with
Great Britain and the United States. It is also the seat of considerable
dyeworks, bleachworks, chemical and woollen factories, and produces
leather and straps, cement, small vehicles, wire-woven goods, carpets,
beer and bricks. The town is well provided with technical schools for
training in the various industries, including commercial, public,
economic and agricultural schools, and has a chamber of commerce. There
are also industrial and historical museums, and collections of painting
and natural history. The local communications are maintained by an
excellent electric tramway system. To the northwest of the town is the
Gothic church of a former Benedictine monastery, dating from 1514-1525,
with a tower of 1897. Chemnitz is a favourite tourist centre for
excursions into the Erzgebirge, the chain of mountains separating Saxony
from Bohemia.

Chemnitz (_Kaminizi_) was originally a settlement of the Serbian Wends
and became a market town in 1143. Its municipal constitution dates from
the 14th century, and it soon became the most important industrial
centre in the mark of Meissen. A monopoly of bleaching was granted to
the town, and thus a considerable trade in woollen and linen yarns was
attracted to Chemnitz; paper was made here, and in the 16th century the
manufacture of cloth was very flourishing. In 1539 the Reformation was
introduced, and in 1546 the Benedictine monastery, founded about 1136 by
the emperor Lothair II. about 2 m. north of the town, was dissolved.
During the Thirty Years' War Chemnitz was plundered by all parties and
its trade was completely ruined, but at the beginning of the 18th
century it had begun to recover. Further progress in this direction was
made during the 19th century, especially after 1834 when Saxony joined
the German Zollverein.

  See Zöllner, _Geschichte der Fabrik- und Handelsstadt Chemnitz_
  (1891); and Straumer, _Die Fabrik- und Handelsstadt Chemnitz_ (1892).



CHEMOTAXIS (from the stem of "chemistry" and Gr. [Greek: taxis],
arrangement), a biological term for the attraction exercised on living
or growing organisms or their members by chemical substances; e.g. the
attraction of the male cells of ferns or mosses by an organic acid or
sugar-solution.



CHENAB (the Greek Acesines), one of the "Five rivers" of the Punjab,
India. It rises in the snowy Himalayan ranges of Kashmir, enters British
territory in the Sialkot district, and flows through the plains of the
Punjab, forming the boundary between the Rechna and the Jech Doabs.
Finally it joins the Jhelum at Trimmu.

The CHENAB COLONY, resulting from the great success of the Chenab Canal
in irrigating the desert of the Bar, was formed out of the three
adjacent districts of Gujranwala, Jhang, and Montgomery in 1892, and
contained in 1901 a population of 791,861. It lies in the Rechna Doab
between the Chenab and Ravi rivers in the north-east of the Jhang
district, and is designed to include an irrigated area of 2½ million
acres. The Chenab Canal (opened 1887) is the largest and most profitable
perennial canal in India. The principal town is Lyallpur, called after
Sir J. Broad wood Lyall, lieutenant-governor of the Punjab 1887-1892,
which gives its name to a district created in 1904.



CHÊNEDOLLÉ, CHARLES JULIEN LIOULT DE (1769-1833), French poet, was born
at Vire (Calvados) on the 4th of November 1769. He early showed a
vocation for poetry, but the outbreak of the Revolution temporarily
diverted his energy. Emigrating in 1791, he fought two campaigns in the
army of Conde, and eventually found his way to Hamburg, where he met
Antoine de Rivarol, of whose brilliant conversation he has left an
account. He also visited Mme de Staël in her retreat at Coppet. On his
return to Paris in 1799 he met Chateaubriand and his sister Lucile (Mme
de Caud), to whom he became deeply attached. After her death in 1804,
Chênedollé returned to Normandy, where he married and became eventually
inspector of the academy of Caen (1812-1832). With the exception of
occasional visits to Paris, he spent the rest of his life in his native
province. He died at the château de Coisel on the 2nd of December 1833.
He published his _Genie de l'Homme_ in 1807, and in 1820 his _Études
poétiques_, which had the misfortune to appear shortly after the
_Méditations_ of Lamartine, so that the author did not receive the
credit of their real originality. Chênedollé had many sympathies with
the romanticists, and was a contributor to their organ, the _Muse
française_. His other works include the _Esprit de Rivarol_ (1808) in
conjunction with F.J.M. Fayolle.

  The works of Chênedollé were edited in 1864 by Sainte-Beuve, who drew
  portraits of him in his _Chateaubriand et son groupe_ and in an
  article contributed to the _Revue des deux mondes_ (June 1849). See
  also E. Helland, _Étude biographique et littéraire sur Chênedollé_
  (1857); Cazin, _Notice sur Chênedollé_ (1869).



CHENERY, THOMAS (1826-1884), English scholar and editor of _The Times_,
was born in 1826 at Barbados. He was educated at Eton and Caius College,
Cambridge. Having been called to the bar, he went out to Constantinople
as _The Times_ correspondent just before the Crimean War, and it was
under the influence there of Algernon Smythe (afterwards Lord
Strangford) that he first turned to those philological studies in which
he became eminent. After the war he returned to London and wrote
regularly for _The Times_ for many years, eventually succeeding Delane
as editor in 1877. He was then an experienced publicist, particularly
well versed in Oriental affairs, an indefatigable worker, with a rapid
and comprehensive judgment, though he lacked Delane's intuition for
public opinion. It was as an Orientalist, however, that he had meantime
earned the highest reputation, his knowledge of Arabic and Hebrew being
almost unrivalled and his gift for languages exceptional. In 1868 he was
appointed Lord Almoner's professor of Arabic at Oxford, and retained his
position until he became editor of _The Times_. He was one of the
company of revisers of the Old Testament. He was secretary for some
time to the Royal Asiatic Society, and published learned editions of the
Arabic classic _The Assemblies of Al-Hariri_ and of the _Machberoth
Ithiel_. He died in London on the 11th of February 1884.



CHENG, TSCHENG or TSCHIANG (Ger. _Scheng_), an ancient Chinese wind
instrument, a primitive organ, containing the principle of the free reed
which found application in the accordion, concertina and harmonium. The
cheng resembles a tea-pot filled with bamboo pipes of graduated lengths.
It consists of a gourd or turned wooden receptacle acting as wind
reservoir, in the side of which is inserted an insufflation tube curved
like a swan's neck or the spout of a tea-pot. The cup-shaped reservoir
is closed by means of a plate of horn pierced with seventeen round holes
arranged round the edge in an unfinished circle, into which fit the
bamboo pipes. The pipes are cylindrical as far as they are visible above
the plate, but the lower end inserted in the wind reservoir is cut to
the shape of a beak, somewhat like the mouthpiece of the clarinet, to
receive the reed. The construction of the free reed is very simple: it
consists of a thin plate of metal--gold according to the Jesuit
missionary Joseph Amiot,[1] but brass in the specimens brought to
Europe--of the thickness of ordinary paper. In this plate is cut a
rectangular flap or tongue which remains fixed at one end, while at the
other the tongue is filed so that, instead of closing the aperture, it
passes freely through, vibrating as the air is forced through the pipe
(see FREE-REED VIBRATOR). The metal plate is fastened with wax
longitudinally across the diameter of the beak end of the pipe, a little
layer of wax being applied also to the free end of the vibrating tongue
for the purpose of tuning by adding weight and impetus. About half an
inch above the horn plate a small round hole or stop is bored through
the pipe, which speaks only when this hole is covered by the finger. A
longitudinal aperture about an inch long cut in the upper end of the
bamboo pipe serves to determine the length of the vibrating column of
air proper to respond to the vibrations of the free reed. The length of
the bamboo above this opening is purely ornamental, as are also four or
five of the seventeen pipes which have no reeds and do not speak, being
merely inserted for the purposes of symmetry in design. The notes of the
cheng, like those of the concertina, speak either by inspiration or
expiration of air, the former being the more usual method. Mahillon
states that performers on the cheng in China are rare, as the method of
playing by inspiration induces inflammation of the throat.[2] Amiot, who
gives a description of the instrument with illustrations showing the
construction, states that in the great Chinese encyclopaedia _Eulh-ya_,
articles _Yu_ and _Ho_, the _Yu_ of ancient China was the large cheng
with nineteen free reeds (twenty-four pipes), and the _Ho_ the small
cheng with thirteen reeds or seventeen pipes described in this article.
The compass of the latter is given by him as the middle octave with
chromatic intervals, the thirteenth note giving the octave of the first.
Mahillon gives the compass of a modern cheng as follows:

[Illustration]

E.F.F. Chladni,[3] who examined a cheng sent from China to Herr Müller,
organist of the church of St Nicholas, Leipzig, at the beginning of the
19th century, gives an excellent description of the instrument,
reproducing in illustration a plate from Giulio Ferrario's work on
costume.[4] Müller's cheng had the same compass as Mahillon's. Chladni's
article was motived by the publication of an account of the exhibition
of G.J. Grenié's _Orgue expressif_, invented about 1810, in the
Conservatoire of Paris.[5] Grenié's invention, perfected by Alexandre
and Debain about 1840, produced the harmonium. Kratzenstein (see under
HARMONIUM) of St Petersburg was the first to apply the free reed to the
organ in the second half of the 18th century. Inventions of similar
instruments, which after a short life were relegated to oblivion,
followed at the beginning of the 19th century. An interesting
reproduction of a Persian cheng dating from the 10th or 11th century is
to be seen on a Persian vase described and illustrated together with a
shawm in the _Gazette archéologique_ (tome xi., 1886).      (K. S.)


FOOTNOTES:

  [1] _Mémoire sur la musique des Chinois_ (Paris, 1779), pp. 78 and
    82, pl. vi., or _Mémoire sur les Chinois_, tome vi. pl. vi.

  [2] _Catalogue descriptif_, vol. ii. (Ghent, 1896), p. 91; also vol.
    i. (1880), pp. 29, 44, 154.

  [3] "Weitere Nachrichten von dem ... chinesischen Blasinstrumente
    Tscheng oder Tschiang," in _Allgemeine musikalische Zeitung_
    (Leipzig, 1821), Bd. xxiii. No. 22, pp. 369, 374 et seq., and
    illustration appendix ii.

  [4] _Il Costume anticho e moderno_ (Milan, 1816), pl. 66, vol. i.

  [5] See _Allg. mus. Zt._ (Leipzig, 1821), Bd. xxiii. Nos. 9 and 10,
    pp. 133 and 149 et seq.



CHÊN-HAI [CHINHAI], a district town of China, in the province of
Cheh-kiang, at the mouth of the Yung-kiang, 12 m. N.E. of Ningpo, in 29°
58' N., 121° 45' E. It lies at the foot of a hill on a tongue of land,
and is partly protected from the sea on the N. by a dike about 3 m.
long, composed entirely of large blocks of hewn granite. The walls are
20 ft. high and 3 m. in circumference. The defences were formerly of
considerable strength, and included a well-built but now dismantled
citadel on a precipitous cliff, 250 ft. high, at the extremity of the
tongue of land on which the town is built. In the neighbourhood an
engagement took place between the English and Chinese in 1841.



CHÉNIER, ANDRÉ DE (1762-1794), French poet, was born at Constantinople
on the 30th of October 1762. His father, Louis Chénier, a native of
Languedoc, after twenty years of successful commerce in the Levant as a
cloth-merchant, was appointed to a position equivalent to that of French
consul at Constantinople. His mother, Elisabeth Santi-Lomaca, whose
sister was grandmother of A. Thiers, was a Greek. When the poet was
three years old his father returned to France, and subsequently from
1768 to 1775 served as consul-general of France in Morocco. The family,
of which André was the third son, and Marie-Joseph (see below) the
fourth, remained in France; and after a few years, during which André
ran wild with "la tante de Carcasonne," he distinguished himself as a
verse-translator from the classics at the Collège de Navarre (the school
in former days of Gerson and Bossuet) in Paris. In 1783 he obtained a
cadetship in a French regiment at Strassburg. But the glamour of the
military life was as soon exhausted by Chénier as it was by Coleridge.
He returned to Paris before the end of the year, was well received by
his family, and mixed in the cultivated circle which frequented the
salon of his mother, among them Lebrun-Pindaré, Lavoisier, Lesueur,
Dorat, Parmy, and a little later the painter David. He was already a
poet by predilection, an idyllist and steeped in the classical archaism
of the time, when, in 1784, his taste for the antique was confirmed by a
visit to Rome made in the company of two schoolfellows, the brothers
Trudaine. From Naples, after visiting Pompeii, he returned to Paris, his
mind fermenting with poetical images and projects, few of which he was
destined to realize. For nearly three years, however, he was enabled to
study and to experiment in verse without any active pressure or
interruption from his family--three precious years in which the first
phase of his art as a writer of idylls and bucolics, imitated to a large
extent from Theocritus, Bion and the Greek anthologists, was elaborated.
Among the poems written or at least sketched during this period were
_L'Oaristys_, _L'Aveugle_, _La Jeune Malade_, _Bacchus_, _Euphrosine_
and _La Jeune Tarentine_, the last a synthesis of his purest manner,
mosaic though it is of reminiscences of at least a dozen classical
poets. As in glyptic so in poetic art, the Hellenism of the time was
decadent and Alexandrine rather than Attic of the best period. But
Chénier is always far more than an imitator. _La Jeune Tarentine_ is a
work of personal emotion and inspiration. The colouring is that of
classic mythology, but the spiritual element is as individual as that of
any classical poem by Milton, Gray, Keats or Tennyson. Apart from his
idylls and his elegies, Chénier also experimented from early youth in
didactic and philosophic verse, and when he commenced his _Hermès_ in
1783 his ambition was to condense the _Encyclopédie_ of Diderot into a
poem somewhat after the manner of Lucretius. This poem was to treat of
man's position in the Universe, first in an isolated state, and then in
society. It remains fragmentary, and though some of the fragments are
fine, its attempt at scientific exposition approximates too closely to
the manner of Erasmus Darwin to suit a modern ear. Another fragment
called _L'Invention_ sums Chénier's _Ars Poetica_ in the verse "Sur des
pensers nouveaux, faisons des vers antiques." _Suzanne_ represents the
torso of a Biblical poem on a very large scale, in six cantos.

In the meantime, André had published nothing, and some of these last
pieces were in fact not yet written, when in November 1787 an
opportunity of a fresh career presented itself. The new ambassador at
the court of St James's, M. de la Luzerne, was connected in some way
with the Chénier family, and he offered to take André with him as his
secretary. The offer was too good to be refused, but the poet hated
himself on the banks of the _fière Tamise_, and wrote in bitter ridicule
of

                  "Ces Anglais.
  Nation toute à vendre à qui peut la payer.
  De contrée en contrée allant au monde entier,
  Offrir sa joie ignoble et son faste grossier."

He seems to have been interested in the poetic diction of Milton and
Thomson, and a few of his verses are remotely inspired by Shakespeare
and Gray. To say, however, that he studied English literature would be
an exaggeration. The events of 1789 and the startling success of his
younger brother, Marie-Joseph, as political playwright and pamphleteer,
concentrated all his thoughts upon France. In April 1790 he could stand
London no longer, and once more joined his parents at Paris in the rue
de Cléry.

The France that he plunged into with such impetuosity was upon the verge
of anarchy. A strong constitutionalist, Chénier took the view that the
Revolution was already complete and that all that remained to be done
was the inauguration of the reign of law. Moderate as were his views and
disinterested as were his motives, his tactics were passionately and
dangerously aggressive. From an idyllist and elegist we find him
suddenly transformed into an unsparing master of poetical satire. His
prose _Avis au peuple français_ (August 24, 1790) was followed by the
rhetorical _Jeu de paume_, a somewhat declamatory moral ode addressed "à
Louis David, peintre." In the meantime he orated at the Feuillants Club,
and contributed frequently to the _Journal de Paris_ from November 1791
to July 1792, when he wrote his scorching _Iambes_ to Collot d'Herbois,
_Sur les Suisses révoltés du regiment de Châteauvieux_. The 10th of
August uprooted his party, his paper and his friends, and the management
of relatives who kept him out of the way in Normandy alone saved him
from the massacre of September. In the month following these events his
democratic brother, Marie-Joseph, had entered the Convention. André's
sombre rage against the course of events found vent in the line on the
Maenads who mutilated the king's Swiss Guard, and in the _Ode à
Charlotte Corday_ congratulating France that "Un scélérat de moins rampe
dans cette fange." At the express request of Malesherbes he furnished
some arguments to the materials collected for the defence of the king.
After the execution he sought a secluded retreat on the Plateau de
Satory at Versailles and took exercise after nightfall. There he wrote
the poems inspired by Fanny (Mme Laurent Lecoulteux), including the
exquisite _Ode à Versailles_, one of his freshest, noblest and most
varied poems.

His solitary life at Versailles lasted nearly a year. On the 7th of
March 1794 he was taken at the house of Mme Piscatory at Passy. Two
obscure agents of the committee of public safety were in search of a
marquise who had flown, but an unknown stranger was found in the house
and arrested on suspicion. This was André, who had come on a visit of
sympathy. He was taken to the Luxembourg and afterwards to Saint-Lazare.
During the 140 days of his imprisonment there he wrote the marvellous
_Iambes_ (in alternate lines of 12 and 8 syllables), which hiss and stab
like poisoned bullets, and which were transmitted to his family by a
venal gaoler. There he wrote the best known of all his verses, the
pathetic _Jeune captive_, a poem at once of enchantment and of despair.
Suffocating in an atmosphere of cruelty and baseness, Chénier's agony
found expression almost to the last in these murderous _Iambes_ which he
launched against the Convention. Ten days before the end, the painter
J.B. Suvée executed the well-known portrait. He might have been
overlooked but for the well-meant, indignant officiousness of his
father. Marie-Joseph had done his best to prevent this, but he could do
nothing more. Robespierre, who was himself on the brink of the volcano,
remembered the venomous sallies in the _Journal de Paris_. At sundown on
the 25th of July 1794, the very day of his condemnation on a bogus
charge of conspiracy, André Chénier was guillotined. The record of his
last moments by La Touche is rather melodramatic and is certainly not
above suspicion.

Incomplete as was his career--he was not quite thirty-two--his life was
cut short in a crescendo of all its nobler elements. Exquisite as was
already his susceptibility to beauty and his mastership of the rarest
poetic material, we cannot doubt that Chénier was preparing for still
higher flights of lyric passion and poetic intensity. Nothing that he
had yet done could be said to compare in promise of assured greatness
with the _Iambes_, the _Odes_ and the _Jeune Captive_. At the moment he
left practically nothing to tell the world of his transcendent genius,
and his reputation has had to be retrieved from oblivion page by page,
and almost poem by poem. During his lifetime only his _Jeu de paume_
(1791) and _Hymne sur les Suisses_ (1792) had been given to the world.
The _Jeune Captive_ appeared in the _Décade philosophique_, Jan. 9,
1795; _La Jeune Tarentine_ in the _Mercure_ of March 22, 1801.
Chateaubriand quoted three or four passages in his _Génie du
christianisme_. Fayette and Lefeuvre-Deumier also gave a few fragments;
but it was not until 1819 that a first imperfect attempt was made by H.
de la Touche to collect the poems in a substantive volume. Since the
appearance of the _editio princeps_ of Chénier's poems in La Touche's
volume, many additional poems and fragments have been discovered, and an
edition of the complete works of the poet, collated with the MSS.
bequeathed to the Bibliothèque Nationale by Mme Elisa de Chénier in
1892, has been edited by Paul Dimoff and published by Delagrave. During
the same period the critical estimates of the poet have fluctuated in a
truly extraordinary manner. Sainte-Beuve in his _Tableau_ of 1828 sang
the praises of Chénier as an heroic forerunner of the Romantic movement
and a precursor of Victor Hugo. Chénier, he said, had "inspired and
determined" Romanticism. This suggestion of modernity in Chénier was
echoed by a chorus of critics who worked the idea to death; in the
meantime, the standard edition of Chénier's works was being prepared by
M. Becq de Fouquières and was issued in 1862, but rearranged and greatly
improved by the editor in 1872. The same patient investigator gave his
New Documents on André Chénier to the world in 1875.

In the second volume of _La Vie littéraire_ Anatole France contests the
theory of Sainte-Beuve. Far from being an initiator, he maintains that
Chénier's poetry is the last expression of an expiring form of art. His
matter and his form belong of right to the classic spirit of the 18th
century. He is a contemporary, not of Hugo and Leconte de Lisle, but of
Suard and Morellet. M. Faguet sums up on the side of M. France in his
volume on the 18th century (1890). Chénier's real disciples, according
to the latest view, are Leconte de Lisle and M. de Heredia, _mosaïstes_
who have at heart the cult of antique and pagan beauty, of "pure art"
and of "objective poetry." Heredia himself reverted to the judgment of
Sainte-Beuve to the effect that Chénier was the first to make modern
verses, and he adds, "I do not know in the French language a more
exquisite fragment than the three hundred verses of the _Bucoliques_."
Chénier's influence has been specially remarkable in Russia, where
Pushkin imitated him, Kogloff translated _La Jeune Captive_, _La jeune
Tarentine_ and other famous pieces, while the critic Vesselovsky
pronounces "Il a rétabli le lyrisme pur dans la poésie française." The
general French verdict on his work is in the main well summed by
Morillot, when he says that, judged by the usual tests of the Romantic
movement of the 'twenties (love for strange literatures of the North,
medievalism, novelties and experiments), Chénier would inevitably have
been excluded from the _cénacle_ of 1827. On the other hand, he exhibits
a decided tendency to the world-ennui and melancholy which was one of
the earlier symptoms of the movement, and he has experimented in French
verse in a manner which would have led to his excommunication by the
typical performers of the 18th century. What is universally admitted is
that Chénier was a very great artist, who like Ronsard opened up sources
of poetry in France which had long seemed dried up. In England it is
easier to feel his attraction than that of some far greater reputations
in French poetry, for, rhetorical though he nearly always is, he yet
reveals something of that quality which to the Northern mind has always
been of the very essence of poetry, that quality which made Sainte-Beuve
say of him that he was the first great poet "personnel et rêveur" in
France since La Fontaine. His diction is still very artificial, the
poetic diction of Delille transformed in the direction of Hugo, but not
very much. On the other hand, his descriptive power in treating of
nature shows far more art than the Trianin school ever attained. His
love of the woodland and his political fervour often remind us of
Shelley, and his delicate perception of Hellenic beauty, and the perfume
of Greek legend, give us almost a foretaste of Keats. For these reasons,
among others, Chénier, whose art is destined to so many vicissitudes of
criticism in his own country, seems assured among English readers of a
place among the Dii Majores of French poetry.

  The Chénier literature of late years has become enormous. His fate has
  been commemorated in numerous plays, pictures and poems, notably in
  the fine epilogue of Sully Prudhomme, the _Stello_ of A. de Vigny, the
  delicate statue by Puech in the Luxembourg, and the well-known
  portrait in the centre of the "Last Days of the Terror." The best
  editions are still those of Becq de Fouquières (Paris, 1862, 1872 and
  1881), though these are now supplemented by those of L. Moland (2
  vols., 1889) and R. Guillard (2 vols., 1899).      (T. SE.)



CHÉNIER, MARIE-JOSEPH BLAISE DE (1764-1811), French poet, dramatist and
politician, younger brother of André de Chénier, was born at
Constantinople on the 11th of February 1764.[1] He was brought up at
Carcassonne, and educated in Paris at the Collège de Navarre. Entering
the army at seventeen, he left it two years afterwards; and at nineteen
he produced _Azémire_, a two-act drama (acted in 1786), and _Edgar, ou
le page supposé_, a comedy (acted in 1785), which were failures. His
_Charles IX_ was kept back for nearly two years by the censor. Chénier
attacked the censorship in three pamphlets, and the commotion aroused by
the controversy raised keen interest in the piece. When it was at last
produced on the 4th of November 1789, it achieved an immense success,
due in part to its political suggestion, and in part to Talma's
magnificent impersonation of Charles IX. Camille Desmoulins said that
the piece had done more for the Revolution than the days of October, and
a contemporary memoir-writer, the marquis de Ferrière, says that the
audience came away "ivre de vengeance et tourmenté d'une soif de sang."
The performance was the occasion of a split among the actors of the
Comédie Française, and the new theatre in the Palais Royal, established
by the dissidents, was inaugurated with _Henri VIII_ (1791), generally
recognized as Chénier's masterpiece; _Jean Calas, ou l'école des juges_
followed in the same year. In 1792 he produced his _Caius Gracchus_,
which was even more revolutionary in tone than its predecessors. It was
nevertheless proscribed in the next year at the instance of the
Montagnard deputy Albitte, for an anti-anarchical hemistich (_Des lois
et non du sang!_); _Fénelon_ (1793) was suspended after a few
representations; and in 1794 his _Timoléon_, set to Étienne Méhul's
music, was also proscribed. This piece was played after the fall of the
Terror, but the fratricide of Timoléon became the text for insinuations
to the effect that by his silence Joseph de Chénier had connived at the
judicial murder of André, whom Joseph's enemies alluded to as _Abel_.
There is absolutely nothing to support the calumny, which has often been
repeated since. In fact, after some fruitless attempts to save his
brother, variously related by his biographers, Joseph became aware that
André's only chance of safety lay in being forgotten by the authorities,
and that ill-advised intervention would only hasten the end. Joseph
Chénier had been a member of the Convention and of the Council of Five
Hundred, and had voted for the death of Louis XVI.; he had a seat in the
tribunate; he belonged to the committees of public instruction, of
general security, and of public safety. He was, nevertheless, suspected
of moderate sentiments, and before the end of the Terror had become a
marked man. His purely political career ended in 1802, when he was
eliminated with others from the tribunate for his opposition to
Napoleon. In 1801 he was one of the educational jury for the Seine; from
1803 to 1806 he was inspector-general of public instruction. He had
allowed himself to be reconciled with Napoleon's government, and
_Cyrus_, represented in 1804, was written in his honour, but he was
temporarily disgraced in 1806 for his _Épître à Voltaire_. In 1806 and
1807 he delivered a course of lectures at the Athénée on the language
and literature of France from the earliest years; and in 1808 at the
emperor's request, he prepared his _Tableau historique de l'état et du
progrès de la littérature française depuis 1789 jusqu'à 1808_, a book
containing some good criticism, though marred by the violent prejudices
of its author. He died on the 10th of January 1811. The list of his
works includes hymns and national songs--among others, the famous _Chant
du départ_; odes, _Sur la mort de Mirabeau_, _Sur l'oligarchie de
Robespierre_, &c.; tragedies which never reached the stage, _Brutus et
Cassius_, _Philippe deux_, _Tibère_; translations from Sophocles and
Lessing, from Gray and Horace, from Tacitus and Aristotle; with elegies,
dithyrambics and Ossianic rhapsodies. As a satirist he possessed great
merit, though he sins from an excess of severity, and is sometimes
malignant and unjust. He is the chief tragic poet of the revolutionary
period, and as Camille Desmoulins expressed it, he decorated Melpomene
with the tricolour cockade.

  See the _Oeuvres complètes de Joseph Chénier_ (8 vols., Paris,
  1823-1826), containing notices of the poet by Arnault and Daunou;
  Charles Labitte, _Études litteraires_ (1846); Henri Welschinger, _Le
  Théâtre révolutionnaire, 1789-1799_ (1881); and A. Lieby, _Étude sur
  le théâtre de Marie-Joseph Chénier_(1902).


FOOTNOTE:

  [1] This is the date given by G. de Chénier in his _La Vérité sur la
    famille de Chénier_ (1844).



CHENILLE (from the Fr. _chenille_, a hairy caterpillar), a twisted
velvet cord, woven so that the short outer threads stand out at right
angles to the central cord, thus giving a resemblance to a caterpillar.
Chenille is used as a trimming for dress and furniture.



CHENONCEAUX, a village of central France, in the department of
Indre-et-Loire, on the right bank of the Cher, 20 m. E. by S. of Tours
on the Orléans railway. Pop. (1906) 216. Chenonceaux owes its interest
to its chateau (see ARCHITECTURE: _Renaissance Architecture in France_),
a building in the Renaissance style on the river Cher, to the left bank
of which it is united by a two-storeyed gallery built upon five arches,
and to the right by a drawbridge flanked by an isolated tower, part of
an earlier building of the 15th century. Founded in 1515 by Thomas
Bohier (d. 1523), financial minister in Normandy, the château was
confiscated by Francis I. in 1535. Henry II. presented it to his
mistress Diane de Poitiers, who on his death was forced to exchange it
for Chaumont-sur-Loire by Catherine de' Medici. The latter built the
gallery which leads to the left bank of the Cher. Chenonceaux passed
successively into the hands of Louise de Vaudémont, wife of Henry III.,
the house of Vendôme, and the family of Bourbon-Condé. In the 18th
century it came into the possession of the farmer-general Claude Dupin
(1684-1769), who entertained the most distinguished people in France
within its walls. In 1864 it was sold to the chemist Théophile Pélouze,
whose wife executed extensive restorations. It subsequently became the
property of the Crédit Foncier, and again passed into private occupancy.



CHENOPODIUM, or GOOSE-FOOT, a genus of erect or prostrate herbs (natural
order Chenopodiaceae), usually growing on the seashore or on waste or
cultivated ground. The green angular stem is often striped with white or
red, and, like the leaves, often more or less covered with mealy hairs.
The leaves are entire, lobed or toothed, often more or less deltoid or
triangular in shape. The minute flowers are bisexual, and borne in dense
axillary or terminal clusters or spikes. The fruit is a membranous
one-seeded utricle often enclosed by the persistent calyx. Ten species
occur in Britain, one of which, _C. Bonus-Henricus_, Good King Henry,
is cultivated as a pot-herb, in lieu of asparagus, under the name
mercury, and all-good.



CHEOPS, in Herodotus, the name of the king who built the Great Pyramid
in Egypt. Following on a period of good rule and prosperity under
Rhampsinitus, Cheops closed the temples, abolished the sacrifices and
made all the Egyptians labour for his monument, working in relays of
100,000 men every three months (see PYRAMID). Proceeding from bad to
worse, he sacrificed the honour of his daughter in order to obtain the
money to complete his pyramid; and the princess built herself besides a
small pyramid of the stones given to her by her lovers. Cheops reigned
50 years and was succeeded by his brother, Chephren, who reigned 56
years and built the second pyramid. During these two reigns the
Egyptians suffered every kind of misery and the temples remained closed.
Herodotus continues that in his own day the Egyptians were unwilling to
name these oppressors and preferred to call the pyramids after a
shepherd named Philition, who pastured his flocks in their
neighbourhood. At length Mycerinus, son of Cheops and successor of
Chephren, reopened the temples and, although he built the Third Pyramid,
allowed the oppressed people to return to their proper occupations.

Cheops, Chephren and Mycerinus are historical personages of the fourth
Egyptian dynasty, in correct order, and they built the three pyramids
attributed to them here. But they are wholly misplaced by Herodotus.
Rhampsinitus, the predecessor of Cheops, appears to represent Rameses
III. of the twentieth dynasty, and Mycerinus in Herodotus is but a few
generations before Psammetichus, the founder of the twenty-sixth
dynasty. Manetho correctly places the great Pyramid kings in Dynasty IV.
In Egyptian the name of Cheops (Chemmis or Chembis in Diodorus Siculus,
Suphis in Manetho) is spelt Hwfw (Khufu), but the pronunciation, in late
times perhaps Khöouf, is uncertain. The Greeks and Romans generally
accepted the view that Herodotus supplies of his character, and
moralized on the uselessness of his stupendous work; but there is
nothing else to prove that the Egyptians themselves execrated his
memory. Modern writers rather dwell on the perfect organization demanded
by his scheme, the training of a nation to combined labour, the level
attained here by art and in the fitting of masonry, and finally the fact
that the Great Pyramid was the oldest of the seven wonders of the
ancient world and now alone of them survives. It seems that
representations of deities, and indeed any representations at all, were
rare upon the polished walls of the great monuments of the fourth
dynasty, and Petrie thinks that he can trace a violent religious
revolution with confiscation of endowments at this time in the temple
remains at Abydos; but none the less the wants of the deities were then
attended to by priests selected from the royal family and the highest in
the land. Khufu's work in the temple of Bubastis is proved by a
surviving fragment, and he is figured slaying his enemy at Sinai before
the god Thoth. In late times the priests of Denderah claimed Khufu as a
benefactor; he was reputed to have built temples to the gods near the
Great Pyramids and Sphinx (where also a pyramid of his daughter Hentsen
is spoken of), and there are incidental notices of him in the medical
and religious literature. The funerary cult of Khufu and Khafr[=e] was
practised under the twenty-sixth dynasty, when so much that had fallen
into disuse and been forgotten was revived. Khufu is a leading figure in
an ancient Egyptian story (Papyrus Westcar), but it is unfortunately
incomplete. He was the founder of the fourth dynasty, and was probably
born in Middle Egypt near Beni Hasan, in a town afterwards known as
"Khufu's Nurse," but was connected with the Memphite third dynasty. Two
tablets at the mines of Wadi Maghara in the peninsula of Sinai, a
granite block from Bubastis, and a beautiful ivory statuette found by
Petrie in the temple at Abydos, are almost all that can be definitely
assigned to Khufu outside the pyramid at Giza and its ruined
accompaniments. His date, according to Petrie, is 3969-3908 B.C., but in
the shorter chronology of Meyer, Breasted and others he reigned (23
years) about a thousand years later, c. 2900 B.C.

  See Herodotus ii. 124; Diodorus Siculus i. 64; Sethe in
  Pauly-Wissowa's _Realencyclopädie_, s.v.; W.M.F. Petrie, _History of
  Egypt_, vol. i., and _Abydos_, part ii. p. 48; J.H. Breasted,
  _History_.        (F. LL. G.)



CHEPSTOW, a market town and river-port in the southern parliamentary
division of Monmouthshire, England, on the Wye, 2 m. above its junction
with the Severn, and on the Great Western railway. Pop. of urban
district (1901) 3067. It occupies the slope of a hill on the western
(left) bank of the river, and is environed by beautiful scenery. The
church of St Mary, originally the conventual chapel of a Benedictine
priory of Norman foundation, has remains of that period in the west
front and the nave, but a rebuilding of the chancel and transepts was
effected in the beginning of the 19th century. The church contains many
interesting monuments. The castle, still a magnificent pile, was founded
in the 11th century by William Fitz-Osbern, earl of Hereford, but was
almost wholly rebuilt in the 13th. There are, however, parts of the
original building in the keep. The castle occupies a splendid site on
the summit of a cliff above the Wye, and covers about 3 acres. The river
is crossed by a fine iron bridge of five arches, erected in 1816, and by
a tubular railway bridge designed by Sir Isambard Brunel. There is a
free passage on the Wye for large vessels as far as the bridge. From the
narrowness and depth of the channel the tide rises suddenly and to a
great height, forming a dangerous bore. The exports are timber, bark,
iron, coal, cider and millstones. Some shipbuilding is carried on.

As the key to the passage of the Wye, Chepstow (_Estrighorel_,
_Striguil_) was the site successively of British, Roman and Saxon
fortifications. Domesday Book records that the Norman castle was built
by William Fitz-Osbern to defend the Roman road into South Wales. On the
confiscation of his son's estates, the castle was granted to the earls
of Pembroke, and after its reversion to the crown in 1306, Edward II. in
1310 granted it to his half-brother Thomas de Brotherton. On the
latter's death it passed, through his daughter Margaret, Lady Segrave,
to the dukes of Norfolk, from whom, after again reverting to the crown,
it passed to the earls of Worcester. It was confiscated by parliament
and settled on Oliver Cromwell, but was restored to the earls in 1660.
The borough must have grown up between 1310, when the castle and vill
were granted to Thomas de Brotherton, and 1432, when John duke of
Norfolk died seised of the castle, manor and borough of Struguil. In
1524 Charles, first earl of Worcester and then lord of the Marches,
granted a new charter of incorporation to the bailiffs and burgesses of
the town, which had fallen into decay. This was sustained until the
reign of Charles II., when, some dispute arising between the earl of
Bridgwater and the burgesses, no bailiff was appointed and the charter
lapsed. Chepstow was afterwards governed by a board of twelve members. A
port since early times, when the lord took dues of ships going up to the
forest of Dean, Chepstow had no ancient market and no manufactures but
that of glass, which was carried on for a short time within the ruins of
the castle.



CHEQUE, or CHECK, in commercial law, a bill of exchange drawn on a
banker and signed by the drawer, requiring the banker to pay on demand a
certain sum in money to or to the order of a specified person or to
bearer. In this, its most modern sense, the cheque is the outcome of the
growth of the banking system of the 19th century. For details see BANKS
AND BANKING: _Law_, and BILL OF EXCHANGE. The word check,[1] of which
"cheque" is a variant now general in English usage, signified merely the
counterfoil or indent of an exchequer bill, or any draft form of
payment, on which was registered the particulars of the principal part,
as a check to alteration or forgery. The check or counterfoil parts
remained in the hands of the banker, the portion given to the customer
being termed a "drawn note" or "draft." From the beginning of the 19th
century the word "cheque" gradually became synonymous with "draft" as
meaning a written order on a banker by a person having money in the
banker's hands, to pay some amount to bearer or to a person named.
Ultimately, it entirely superseded the word "draft," and has now a
statutory definition (Bills of Exchange Act 1882, s. 73)--" a bill of
exchange drawn on a banker payable on demand." The word "draft" has come
to have a wider meaning, that of a bill drawn by one person on another
for a sum of money, or an order (whether on a banker or other) to pay
money. The employment of cheques as a method of payment offering greater
convenience than coin is almost universal in Great Britain and the
United States. Of the transactions through the banks of the United
Kingdom between 86 and 90% are conducted by means of cheques, and an
even higher proportion in the United States. On the continent of Europe
the use of cheques, formerly rare, is becoming more general,
particularly in France, and to some extent in Germany.


FOOTNOTE:

  [1] The original meaning of "check" is a move in the game of chess
    which directly attacks the king; the word comes through the Old Fr.
    _eschec_, _eschac_, from the Med. Lat. form _scaccus_ of the Persian
    _shah_, king, i.e. the king in the game of chess; cf. the origin of
    "mate" from the Arabic _shah-mat_, the king is dead. The word was
    early used in a transferred sense of a stoppage or rebuff, and so is
    applied to anything which stops or hinders a matter in progress, or
    which controls or restrains anything, hence a token, ticket or
    counterfoil which serves as a means of identification, &c.



CHER, a department of central France, embracing the eastern part of the
ancient province of Berry, and parts of Bourbonnais, Nivernais and
Orléanais, bounded N. by the department of Loiret, W. by Loir-et-Cher and
Indre, S. by Allier and Creuse, and E. by Nièvre. Pop. (1906) 343,484.
Area 2819 sq. m. The territory of the department is elevated in the
south, where one point reaches 1654 ft., and in the east. The centre is
occupied by a wide calcareous table-land, to the north of which stretches
the plain of Sologne. The principal rivers, besides the Cher and its
tributaries, are the Grande Sauldre and the Petite Sauldre on the north,
but the Loire and Allier, though not falling within the department, drain
the eastern districts, and are available for navigation. The Cher itself
becomes navigable when it receives the Arnon and Yèvre, and the
communications of the department are greatly facilitated by the Canal du
Berry, which traverses it from east to west, the lateral canal of the
Loire, which follows the left bank of that river, and the canal of the
Sauldre. The climate is temperate, and the rainfall moderate. Except in
the Sologne, the soil is generally fertile, but varies considerably in
different localities. The most productive region is that on the east,
which belongs to the valley of the Loire; the central districts are
tolerably fertile but marshy, being often flooded by the Cher; while in
the south and south-west there is a considerable extent of dry and
fertile land. Wheat and oats are largely cultivated, while hemp,
vegetables and various fruits are also produced. The vine flourishes
chiefly in the east of the arrondissement of Sancerre. The department
contains a comparatively large extent of pasturage, which has given rise
to a considerable trade in horses, cattle, sheep and wool for the
northern markets. Nearly one-fifth of the whole area consists of forest.
Mines of iron are worked, and various sorts of stone are quarried. Brick,
porcelain and glassworks employ large numbers of the inhabitants. There
are also flour-mills, distilleries, oil-works, saw-mills and tanneries.
Bourges and Vierzon are metallurgical and engineering centres. Coal and
wine are leading imports, while cereals, timber, wool, fruit and
industrial products are exported. The department is served by the Orléans
railway, and possesses in all more than 300 m. of navigable waterways. It
is divided into three arrondissements (29 cantons, 292 communes)
cognominal with the towns of Bourges, Saint-Amand-Mont-Rond, and
Sancerre, of which the first is the capital, the seat of an archbishop
and of a court of appeal and headquarters of the VIII. army-corps. The
department belongs to the _académie_ (educational division) of Paris.
Bourges, Saint-Amand-Mont-Rond, Vierzon and Sancerre (q.v.) are the
principal towns. Méhun-sur-Yèvre (pop. 5227), a town with an active
manufacture of porcelain, has a Romanesque church and a château of the
14th century. Among the other interesting churches of the department,
that at St Satur has a fine choir of the 14th and 15th centuries; those
of Dun-sur-Auron, Plaimpied, Aix d'Angillon and Jeanvrin are Romanesque
in style, while Aubigny-Ville has a church of the 12th, 13th and 15th
centuries and a château of later date. Drevant, built on the site of a
Roman town, preserves ruins of a large theatre and other remains. Among
the megalithic monuments of Cher, the most notable is that at
Villeneuve-sur-Cher, known as the Pierre-de-la-Roche.



CHERAT, a hill cantonment and sanatorium in the Peshawar district of the
North-West Frontier Province, India, 34 m. S.E. of Peshawar. It is
situated at an elevation of 4500 ft, on the west of the Khattak range,
which divides the Peshawar from the Kohat district. It was first used in
1861, and since then has been employed during the hot weather as a
health station for the British troops quartered in the hot and malarious
vale of Peshawar.



CHERBOURG, a naval station, fortified town and seaport of north-western
France, capital of an arrondissement in the department of Manche, on the
English Channel, 232 m. W.N.W. of Paris on the Ouest-État railway. Pop.
(1906) town, 35,710; commune, 43,827. Cherbourg is situated at the mouth
of the Divette, on a small bay at the apex of the indentation formed by
the northern shore of the peninsula of Cotentin. Apart from a fine
hospital and the church of La Trinité dating from the 15th century, the
town has no buildings of special interest. A rich collection of
paintings is housed in the hôtel de ville. A statue of the painter J.F.
Millet, born near Cherbourg, stands in the public garden, and there is
an equestrian statue of Napoleon I. in the square named after him.
Cherbourg is a fortified place of the first class, headquarters of one
of the five naval arrondissements of France, and the seat of a
sub-prefect. It has tribunals of first instance and of commerce, a
chamber of commerce, a lycée and a naval school. The chief industries of
the town proper are fishing, saw-milling, tanning, leather-dressing,
ship-building, iron and copper-founding, rope-making and the manufacture
of agricultural implements. There are stone quarries in the environs,
and the town has trade in farm produce.

Cherbourg derives its chief importance from its naval and commercial
harbours, which are distant from each other about half a mile. The
former consists of three main basins cut out of the rock, and has an
area of 55 acres. The minimum depth of water is 30 ft. Connected with
the harbour are dry docks, the yards where the largest ships in the
French navy are constructed, magazines, rope walks, and the various
workshops requisite for a naval arsenal of the first class. The works
and town are carefully guarded on every side by redoubts and
fortifications, and are commanded by batteries on the surrounding hills.
There is a large naval hospital close to the harbour. The commerical
harbour at the mouth of the Divette communicates with the sea by a
channel 650 yds. long. It consists of two parts, an outer and tidal
harbour 17½ acres in extent, and an inner basin 15 acres in extent, with
a depth on sill at ordinary spring tide of 25 ft. Outside these harbours
is the triangular bay, which forms the roadstead of Cherbourg. The bay
is admirably sheltered by the land on every side but the north. On that
side it is sheltered by a huge breakwater, over 2 m. in length, with a
width of 650 ft. at its base and 30 ft. at its summit, which is
protected by forts, and leaves passages for vessels to the east and
west. These passages are guarded by forts placed on islands intervening
between the breakwater and the mainland, and themselves united to the
land by breakwaters. The surface within these barriers amounts to about
3700 acres. Cherbourg is a port of call for the American, North German
Lloyd and other important lines of transatlantic steamers. The chief
exports are stone for road-making, butter, eggs and vegetables; the
chief imports are coal, timber, superphosphates and wine from Algeria.
Great Britain is the principal customer.

Cherbourg is supposed by some investigators to occupy the site of the
Roman station of _Coriallum_, but nothing definite is known about its
origin. The name was long regarded as a corruption of _Caesaris Burgus_
(Caesar's Borough). William the Conqueror, under whom it appears as
_Carusbur_, provided it with a hospital and a church; and Henry II. of
England on several occasions chose it as his residence. In 1295 it was
pillaged by an English fleet from Yarmouth; and in the 14th century it
frequently suffered during the wars against the English. Captured by the
English in 1418 after a four months' siege, it was recovered by Charles
VII. of France in 1450. An attempt was made under Louis XIV. to
construct a military port; but the fortifications were dismantled in
1688, and further damage was inflicted by the English in 1758. In 1686
Vauban planned harbour-works which were begun under Louis XVI. and
continued by Napoleon I. It was left, however, to Louis Philippe, and
particularly to Napoleon III., to complete them, and their successful
realization was celebrated in 1858, in the presence of the queen of
England, against whose dominions they had at one time been mainly
directed. At the close of 1857, £8,000,000, of which the breakwater cost
over £2,500,000, had been expended on the works; in 1889 a further sum
of £680,000 was voted by the Chamber of Deputies for the improvement of
the port.



CHERBULIEZ, CHARLES VICTOR (1829-1899), French novelist and
miscellaneous writer, was born on the 19th of July 1829, at Geneva,
where his father, André Cherbuliez (1795-1874), was a classical
professor at the university. He was descended from a family of
Protestant refugees, and many years later Victor Cherbuliez resumed his
French nationality, taking advantage of an act passed in the early days
of the Revolution. Geneva was the scene of his early education; thence
he proceeded to Paris, and afterwards to the universities of Bonn and
Berlin. He returned to his native town and engaged in the profession of
teaching. After his resumption of French citizenship he was elected a
member of the Academy (1881), and having received the Legion of Honour
in 1870, he was promoted to be officer of the order in 1892. He died on
the 1st of July 1899. Cherbuliez was a voluminous and successful writer
of fiction. His first book, originally published in 1860, reappeared in
1864 under the title of _Un Cheval de Phidias_: it is a romantic study
of art in the golden age of Athens. He went on to produce a series of
novels, of which the following are the best known:--_Le Comte Kostia_
(1863), _Le Prince Vitale_ (1864), _Le Roman d'une honnête femme_
(1866), _L'Aventure de Ladislas Bolski_ (1869), _Miss Ravel_ (1875),
_Samuel Brohl et Cie_ (1877), _L'Idée de Jean Teterol_ (1878), _Noirs et
rouges_ (1881), _La Vocation du Comte Ghislain_ (1888), _Une Gageure_
(1890), _Le Secret du précepteur_ (1893), _Jacquine Vanesse_ (1898), &c.
Most of these novels first appeared in the _Revue des deux mondes_, to
which Cherbuliez also contributed a number of political and learned
articles, usually printed with the pseudonym G. Valbert. Many of these
have been published in collected form under the titles _L'Allemagne
politique_ (1870), _L'Espagne politique_ (1874), _Profils étrangers_
(1889), _L'Art et la nature_ (1892), &c. The volume _Études de
littérature et d'art_ (1873) includes articles for the most part
reprinted from _Le Temps_. The earlier novels of Cherbuliez have been
said with truth to show marked traces of the influence of George Sand;
and in spite of modification, his method was that of an older school. He
did not possess the sombre power or the intensely analytical skill of
some of his later contemporaries, but his books are distinguished by a
freshness and honesty, fortified by cosmopolitan knowledge and lightened
by unobtrusive humour, which fully account for their wide popularity in
many countries besides his own. His genius was the reverse of dramatic,
and attempts to present two of his stories on the stage have not
succeeded. His essays have all the merits due to liberal observation and
thoroughness of treatment; their style, like that of the novels, is
admirably lucid and correct.        (C.)



CHERCHEL, a seaport of Algeria, in the arrondissement and department of
Algiers, 55 m. W. of the capital. It is the centre of an agricultural
and vine-growing district, but is commercially of no great importance,
the port, which consists of part only of the inner port of Roman days,
being small and the entry difficult. The town is chiefly noteworthy for
the extensive ruins of former cities on the same site. Of existing
buildings the most remarkable is the great Mosque of the Hundred
Columns, now used as a military hospital. The mosque contains 89 columns
of diorite, surmounted by a variety of capitals brought from other
buildings. The population of the town in 1906 was 4733; of the commune
of which Cherchel is the centre 11,088.

Cherchel was a city of the Carthaginians, who named it Jol. Juba II. (25
B.C.) made it the capital of the Mauretanian kingdom under the name of
Caesarea. Juba's tomb, the so-called Tombeau de la Chrétienne (see
ALGERIA), is 7½ m. E. of the town. Destroyed by the Vandals, Caesarea
regained some of its importance under the Byzantines. Taken by the Arabs
it was renamed by them Cherchel. Khair-ed-Din Barbarossa captured the
city in 1520 and annexed it to his Algerian pashalik. In the early years
of the 18th century it was a commercial city of some importance, but was
laid in ruins by a terrible earthquake in 1738. In 1840 the town was
occupied by the French. The ruins suffered greatly from vandalism during
the early period of French rule, many portable objects being removed to
museums in Paris or Algiers, and most of the monuments destroyed for the
sake of their stone. Thus the dressed stones of the ancient theatre
served to build barracks; the material of the hippodrome went to build
the church; while the portico of the hippodrome, supported by granite
and marble columns, and approached by a fine flight of steps, was
destroyed by Cardinal Lavigerie in a search for the tomb of St Marciana.
The fort built by Arouj Barbarossa, elder brother of Khair-ed-Din, was
completely destroyed by the French. There are many fragments of a white
marble temple. The ancient cisterns still supply the town with water.
The museum contains some of the finest statues discovered in Africa.
They include colossal figures of Aesculapius and Bacchus, and the lower
half of a seated Egyptian divinity in black basalt, bearing the
cartouche of Tethmosis (Thothmes) I. This statue was found at Cherchel,
and is held by some archaeologists to indicate an Egyptian settlement
here about 1500 B.C.

  See AFRICA, ROMAN, and the description of the museum by P. Gauckler in
  the _Musées et collections archéologiques de l'Algérie_.



CHERCHEN, a town of East Turkestan, situated at the northern foot of the
Altyn-tagh, a range of the Kuen-lun, in 85° 35' E., and on the
Cherchen-darya, at an altitude of 4100 ft. It straggles mostly along the
irrigation channels that go off from the left side of the river, and in
1900 had a population of about 2000. The Cherchen-darya, which rises in
the Arka-tagh, a more southerly range of the Kuen-lun, in 87° E. and 36°
20' N., flows north until it strikes the desert below Cherchen, after
which it turns north-east and meanders through a wide bed (300-400 ft.),
beset with dense reeds and flanked by older channels. It is probable
that anciently it entered the disused channel of the Ettek-tarim, but at
present it joins the existing Tarim in the lake of Kara-buran, a sort of
lacustrine "ante-room" to the Kara-koshun (N.M. Przhevalsky's Lop-nor).
At its entrance into the former lake the Cherchen-darya forms a broad
delta. The river is frozen in its lower course for two to three months
in the winter. From the foot of the mountains to the oasis of Cherchen
it has a fall of nearly 4000 ft., whereas in the 300 m. or so from
Cherchen to the Kara-buran the fall is 1400 ft. The total length is
500-600 m., and the drainage basin measures 6000-7000 sq. m.

  See Sven Hedin, _Scientific Results of a Journey in Central Asia,
  1899-1902_, vols. i. and ii. (1905-1906); also TAKLA-MAKAN.



CHEREMISSES, or TCHEREMISSES, a Finnish people living in isolated groups
in the governments of Kazan, Viatka, Novgorod, Perm, Kostroma and Ufa,
eastern Russia. Their name for themselves is Mori or Mari (people),
possibly identifiable with the ancient Merians of Suzdalia. Their
language belongs to the Finno-Ugrian family. They number some 240,000.
There are two distinct physical types: one of middle height,
black-haired, brown skin and flat-faced; the other short, fair-haired,
white skinned, with narrow eyes and straight short noses. Those who live
on the right bank of the Volga are sometimes known as Hill Cheremis, and
are taller and stronger than those who inhabit the swamps of the left
bank. They are farmers and herd horses and cattle. Their religion is a
hotchpotch of Shamanism, Mahommedanism and Christianity. They are
usually monogamous. The chief ceremony of marriage is a forcible
abduction of the bride. The women, naturally ugly, are often disfigured
by sore eyes caused by the smoky atmosphere of the huts. They wear a
head-dress, trimmed with glass jewels, forming a hood behind stiffened
with metal. On their breasts they carry a breastplate formed of coins,
small bells and copper disks.

  See Smirinov, _Mordres et Tcheremisses_ (Paris, 1895); J. Abercromby,
  _Pre- and Proto-historic Finns_ (London, 1898).



CHERIBON, a residency of the island of Java, Dutch East Indies, bounded
S. and W. by the Preanger regencies, N.W. by Krawang, N. by the Java
Sea, and E. by the residencies of Tegal and Banyumas. Pop. (1897)
1,577,521, including 867 Europeans, 21,108 Chinese, and 2016 Arabs and
other Asiatic foreigners. The natives consist of Middle Javanese in the
north and Sundanese in the south. Cheribon has been for many centuries
the centre of Islamism in western Java, and is also the seat of a
fanatical Mahommedan sect controlled from Mecca. The native population
is on the whole orderly and prosperous. The northern half of the
residency is flat and marshy in places, especially in the north-western
corner, while the southern half is mountainous. In the middle stands the
huge volcano Cherimai, clad with virgin forest and coffee plantations,
and surrounded at its foot by rice fields. South-south-west of Cherimai
on the Preanger border is the Sawal volcano, at whose foot is the
beautiful Penjalu lake. Sulphur and salt springs occur on the slopes of
Cherimai, and near Palimanan there is a cavernous hole called Guwagalang
(or Payagalang), which exhales carbonic acid gas, and is considered holy
by the natives and guarded by priests. There is a similar hole in the
Preanger. The principal products of cultivation are sugar, coffee, rice
and also tea and pulse (_rachang_), the plantations being for the most
part owned by Europeans. The chief towns are Cheribon, a seaport and
capital of the residency, the seaport of Indramaya, Palimanan,
Majalengka, Kuningan and Chiamis. Cheribon has a good open roadstead.
The town is very old and irregularly built, and the climate is
unhealthy; nevertheless it has a lively export trade in sugar and coffee
and is a regular port of call. In 1908 the two descendants of the old
sultans of Cheribon still resided there in their respective _Kratons_ or
palaces, and each received an annual income of over £1500 for the loss
of his privileges. A country residence belonging to one of the sultans
is situated close to Cheribon and is much visited on account of its
fantastic architecture. Indramaya was a considerable trading place in
the days of the early Portuguese and Dutch traders. Kuningan is famous
for a breed of small but strong horses.



CHERKASY (Polish, _Czerkasy_), a town of Russia, in the government of
Kiev, 96 m. S.E. of Kiev, on the right bank of the Dnieper. Pop. (1883)
15,740; (1897) 26,619. The inhabitants (Little Russians) are mostly
employed in agriculture and gardening; but sugar and tobacco are
manufactured and spirits distilled. Cherkasy was an important town of
the Ukraine in the 15th century, and remained so, under Polish rule,
until the revolt of the Cossack _hetman_ Chmielnicki (1648). It was
annexed by Russia in 1795.



CHERNIGOV, a government of Little Russia, on the left bank of the
Dnieper, bounded by the governments of Mogilev and Smolensk on the N.,
Orel and Kursk on the E., Poltava on the S., and Kiev and Minsk on the
W. Area, 20,233 sq. m. Its surface is an undulating plain, 650 to 750
ft. high in the north and 370 to 600 ft. in the south, deeply grooved by
ravines and the valleys of the rivers. In the north, beyond the Desna
river, about one-third of the area is under forest (rapidly
disappearing), and marshes occur along the courses of the rivers; while
to the south of the Desna the soil is dry and sometimes sandy, and
gradually it assumes the characters of a steppe-land as one proceeds
southward. The government is drained by the Dnieper, which forms its
western boundary for 180 m., and by its tributary the Desna. The latter,
which flows through Chernigov for nearly 350 m., is navigable, and
timber is brought down its tributaries. The climate is much colder in
the wooded tracts of the north than in the south; the average yearly
temperature at the city of Chernigov is 44.4° F. (January, 23°; July
68.5°).

The population reached 1,996,250 in 1883, 2,316,818 in 1897, and
2,746,300 (estimate) in 1906. It is chiefly Little Russian (85.6%); but
Great Russians (6.1%), mostly Raskolniks, i.e. nonconformists, and White
Russians (5.6%) inhabit the northern districts. There are, besides, some
Germans, as well as Greeks, at Nyezhin. Agriculture is the principal
occupation; in the north, however, many of the inhabitants are engaged
in the timber trade, and in the production of tar, pitch, wooden wares,
leather goods and so forth. Cattle-breeding is carried on in the central
districts. Beet is extensively cultivated. The cultivation of tobacco is
increasing. Hemp is widely grown in the north, and the milder climate of
the south encourages gardening. Bee-keeping is extensively carried on by
the Raskolniks. Limestone, grindstones, china-clay and building-stone
are quarried. Manufactures have begun to develop rapidly of late, the
most important being sugar-works, distilleries, cloth-mills and
glass-works. The government is divided into fifteen districts, their
chief towns being Chernigov (q.v.), Borzna (pop. 12,458 in 1897),
Glukhov (14,856), Gorodnya (4197), Konotop (23,083), Kozelets (5160),
Krolevets (10,375), Mglin (7631), Novgorod-Syeversk (9185), Novozybkov
(15,480), Nyezhin (32,481), Oster (5384), Sosnitsa (2507), Starodub
(12,451) and Surazh (4004).



CHERNIGOV, a town of Russia, capital of the above government, on the
right bank of the Desna, nearly half a mile from the river, 141 m. by
rail N.E. of Kiev on a branch line. Pop. (1897) 27,006. It is an
archiepiscopal see and possesses a cathedral of the 11th century. In 907
the city is mentioned in the treaty of Oleg as next in importance to
Kiev, and in the 11th century it became the capital of the principality
of Syeversk and an important commercial city. The Mongol invasion put an
end to its prosperity in 1239. Lithuania annexed it in the 14th century,
but it was soon seized by Poland, which held it until the 17th century.
In 1686 it was definitely annexed to Russia.



CHEROKEE (native _Tsalagi_, "cave people"), a tribe of North American
Indians of Iroquoian stock. Next to the Navaho they are the largest
tribe in the United States and live mostly in Oklahoma (formerly Indian
territory). Before their removal they possessed a large tract of country
now distributed among the states of Alabama, Georgia, Mississippi,
Tennessee and the west of Florida. Their chief divisions were then
settled around the head-waters of the Savannah and Tennessee rivers, and
were distinguished as the Elati Tsalagi or Lower Cherokees, i.e. those
in the plains, and Atali Tsalagi or Upper Cherokees, i.e. those on the
mountains. They were further divided into seven exogamous clans.
Fernando de Soto travelled through their country in 1540, and during the
next three centuries they were important factors in the history of the
south. They attached themselves to the English in the disputes and
contests which arose between the European colonizers, formally
recognized the English king in 1730, and in 1755 ceded a part of their
territory and permitted the erection of English forts. Unfortunately
this amity was interrupted not long after; but peace was again restored
in 1761. When the revolutionary war broke out they sided with the
royalist party. This led to their subjugation by the new republic, and
they had to surrender that part of their lands which lay to the south of
the Savannah and east of the Chattahoochee. Peace was made in 1781, and
in 1785 they recognized the supremacy of the United States and were
confirmed in their possessions. In 1820 they adopted a civilized form of
government, and in 1827, as a "Nation," a formal constitution. The
gradual advance of white immigration soon led to disputes with the
settlers, who desired their removal, and exodus after exodus took place;
a small part of the tribe agreed (1835) to remove to another district,
but the main body remained. An appeal was made by them to the United
States government; but President Andrew Jackson refused to interfere. A
force of 2000 men, under the command of General Winfield Scott, was sent
in 1838, and the Cherokees were compelled to emigrate to their present
position. After the settlement various disagreements between the eastern
and western Cherokees continued for some time, but in 1839 a union was
effected. In the Civil War they all at first sided with the South; but
before long a strong party joined the North, and this led to a
disastrous internecine struggle. On the close of the contest they were
confirmed in the possession of their territory, but were forced to give
a portion of their lands to their emancipated slaves. Their later
history is mainly a story of hopeless struggle to maintain their tribal
independence against the white man. In 1892 they sold their western
territory known as the "Cherokee outlet." Until 1906, when tribal
government virtually ceased, the "nation" had an elected chief, a senate
and house of representatives. Many of them have become Christians,
schools have been established and there is a tribal press. Those in
Oklahoma still number some 26,000, though most are of mixed blood. A
group, known as the Eastern Band, some 1400 strong, are on a reservation
in North Carolina. Their language consists of two dialects--a third,
that of the "Lower" branch, having been lost. The syllabic alphabet
invented in 1821 by George Guess (Sequoyah) is the character employed.

  See also _Handbook of American Indians_(Washington, 1907); T.V.
  Parker, _Cherokee Indians_ (N.Y., 1909); and INDIANS, NORTH AMERICAN.



CHEROOT, or SHEROOT (from the Tamil word "shuruttu," a roll), a cigar
made from tobacco grown in southern India and the Philippine Islands. It
was once esteemed very highly for its delicate flavour. A cheroot
differs from other cigars in having both ends cut square, instead of one
being pointed, and one end considerably larger than the other.



CHERRAPUNJI, a village in the Khasi hills district of Assam. It is
notable as having the heaviest known rainfall in the world. In 1861 it
registered a total of 905 in., and its annual average is 458 in. This
excessive rainfall is caused by the fact that Cherrapunji stands on the
edge of the plateau overlooking the plains of Bengal, where it catches
the full force of the monsoon as it rises from the sea. There is a good
coal-seam in the vicinity.



CHERRY. As a cultivated fruit-tree the cherry is generally supposed to
be of Asiatic origin, whence, according to Pliny, it was brought to
Italy by Lucullus after his defeat of Mithradates, king of Pontus, 68
B.C. As with most plants which have been long and extensively
cultivated, it is a matter of difficulty, if not an impossibility, to
identify the parent stock of the numerous cultivated varieties of
cherry; but they are generally referred to two species: _Prunus
Cerasus_, the wild or dwarf cherry, the origin of the morello, duke and
Kentish cherries, and _P. Avium_, the gean, the origin of the geans,
hearts and bigarreaus. Both species grow wild through Europe and western
Asia to the Himalayas, but the dwarf cherry has the more restricted
range of the two in Britain, as it does not occur in Scotland and is
rare in Ireland. The cherries form a section _Cerasus_ of the genus
_Prunus_; and they have sometimes been separated as a distinct genus
from the plums proper; both have a stone-fruit or drupe, but the drupe
of the cherry differs from that of the plum in not having a waxy bloom;
further, the leaves of the plum are rolled (_convolute_) in the bud,
while those of the cherry are folded (conduplicate).

The cherries are trees of moderate size and shrubs, having smooth,
serrate leaves and white flowers. They are natives of the temperate
regions of both hemispheres; and the cultivated varieties ripen their
fruit in Norway as far as 63° N. The geans are generally distinguished
from the common cherry by the greater size of the trees, and the deeper
colour and comparative insipidity of the flesh in the ripe fruit, which
adheres firmly to the "nut" or stone; but among the very numerous
cultivated varieties specific distinctions shade away so that the fruit
cannot be ranged under these two heads. The leading varieties are
recognized as bigarreaus, dukes, morellos and geans. Several varieties
are cultivated as ornamental trees and on account of their flowers.

The cherry is a well-flavoured sub-acid fruit, and is much esteemed for
dessert. Some of the varieties are particularly selected for pies,
tarts, &c., and others for the preparation of preserves, and for making
cherry brandy. The fruit is also very extensively employed in the
preparation of the liqueurs known as kirschwasser, ratafia and
maraschino. Kirschwasser is made chiefly on the upper Rhine from the
wild black gean, and in the manufacture the entire fruit-flesh and
kernels are pulped up and allowed to ferment. By distillation of the
fermented pulp the liqueur is obtained in a pure, colourless condition.
Ratafia is similarly manufactured, also by preference from a gean.
Maraschino, a highly valued liqueur, the best of which is produced at
Zara in Dalmatia, differs from these in being distilled from a cherry
called marasca, the pulp of which is mixed with honey, honey or sugar
being added to the distillate for sweetening. It is also said that the
flavour is heightened by the use of the leaves of the perfumed cherry,
_Prunus Mahaleb_, a native of central and southern Europe.

The wood of the cherry tree is valued by cabinetmakers, and that of the
gean tree is largely used in the manufacture of tobacco pipes. The
American wild cherry, _Prunus serotina_, is much sought after, its wood
being compact, fine-grained, not liable to warp, and susceptible of
receiving a brilliant polish. The kernels of the perfumed cherry, _P.
Mahaleb_, are used in confectionery and for scent. A gum exudes from the
stem of cherry trees similar in its properties to gum arabic.

The cherry is increased by budding on the wild gean, obtained by sowing
the stones of the small black or red wild cherries. To secure very dwarf
trees the _Prunus Mahaleb_ has been used for the May duke, Kentish,
morello and analogous sorts, but it is not adapted for strong-growing
varieties like the bigarreaus. The stocks are budded, or, more rarely,
grafted, at the usual seasons. The cherry prefers a free, loamy soil,
with a well-drained subsoil. Stiff soils and dry gravelly subsoils are
both unsuitable, though the trees require a large amount of moisture,
particularly the large-leaved sorts, such as the bigarreaus. For
standard trees, the bigarreau section should be planted 30 ft. apart, or
more, in rich soil, and the May duke, morello and similar varieties 20
or 25 ft. apart; while, as trained trees against walls and espaliers,
from 20 to 24 ft. should be allowed for the former, and from 15 to 20
ft. for the latter. In forming the stems of a standard tree the
temporary side-shoots should not be allowed to attain too great a
length, and should not be more than two years old when they are cut
close to the stem. The first three shoots retained to form the head
should be shortened to about 15 in., and two shoots from each
encouraged, one at the end, and the other 3 or 4 in. lower down. When
these have become established, very little pruning will be required, and
that chiefly to keep the principal branches as nearly equal in strength
as possible for the first few years. Espalier trees should have the
branches about a foot apart, starting from the stem with an upward
curve, and then being trained horizontally. In summer pruning the shoots
on the upper branches must be shortened at least a week before those on
the lower ones. After a year or two clusters of fruit buds will be
developed on spurs along the branches, and those spurs will continue
productive for an indefinite period. For wall trees any form of training
may be adopted; but as the fruit is always finest on young spurs,
fan-training is probably the most advantageous. A succession of young
shoots should be laid in every year. The morello, which is of twiggy
growth and bears on the young wood, must be trained in the fan form, and
care should be taken to avoid the very common error of crowding its
branches.

_Forcing_.--The cherry will not endure a high temperature nor close
atmosphere. A heat of 45° at night will be sufficient at starting, this
being gradually increased during the first few weeks to 55°, but lowered
again when the blossom buds are about to open. After stoning the
temperature may be again gradually raised to 60°, and may go up to 70°
by day, or 75° by sun heat, and 60° at night. The best forcing cherries
are the May duke and the royal duke, the duke cherries being of more
compact growth than the bigarreau tribe and generally setting better;
nevertheless a few of the larger kinds, such as bigarreau Napoléon,
black tartarian and St Margaret's, should be forced for variety. The
trees may be either planted out in tolerably rich soil, or grown in
large pots of good turfy friable calcareous loam mixed with rotten dung.
If the plants are small, they may be put into 12-in. pots in the first
instance, and after a year shifted into 15-in. pots early in autumn,
and plunged in some loose or even very slightly fermenting material. The
soil of the pots should be protected from snow-showers and cold rains.
Occasionally trees have been taken up in autumn with balls, potted and
forced in the following spring; but those which have been established a
year in the pots are to be preferred. Such only as are well furnished
with blossom-buds should be selected. The trees should be removed to the
forcing house in the beginning of December, if fruit be required very
early in the season. During the first and second weeks it may be kept
nearly close; but, as vegetation advances, air becomes absolutely
necessary during the day, and even at night when the weather will
permit. If forcing is commenced about the middle or third week of
December, the fruit ought to be ripe by about the end of March. After
the fruit is gathered, the trees should be duly supplied with water at
the root, and the foliage kept well syringed till the wood is mature.
(See also FRUIT AND FLOWER FARMING.)



CHERRYVALE, a city of Montgomery county, Kansas, U.S.A., about 140 m.
S.S.E. of Kansas City. Pop. (1890) 2104; (1900) 3472, including 180
negroes; (1905, state census) 5089; (1910) 4304. It is served by the
Atchison, Topeka & Santa Fé, and the main line and a branch (of which it
is a terminus) of the St Louis & San Francisco railways. It is in a
farming district and in the Kansas natural-gas and oil-field, and has
large zinc smelters, an oil refinery, and various manufactures,
including vitrified brick, flour, glass, cement and ploughs. Cherryvale
was laid out in 1871 by the Kansas City, Lawrence & South Kansas Railway
Company (later absorbed by the Atchison, Topeka & Santa Fé). The main
part of the town was destroyed by fire in 1873, but was soon rebuilt,
and in 1880 Cherryvale became a city of the third and afterwards of the
second class. Natural gas, which is used as a factory fuel and for
street and domestic lighting, was found here in 1889, and oil several
years later.



CHERRY VALLEY, a village of Otsego county, New York, U.S.A., in a
township of the same name, 68 m. N.W. of Albany. Pop. (1890) 685; (1900)
772; (1905) 746; (1910) 792; of the township (1910) 1706. It is served
by the Delaware & Hudson railway. Cherry Valley is in the centre of a
rich farming and dairying region, has a chair factory, and is a summer
resort with sulphur and lithia springs. It was the scene of a terrible
massacre during the War of Independence. The village was attacked on the
11th of November 1778 by Walter Butler (d. 1781) and Joseph Brant with a
force of 800 Indians and Tories, who killed about 50 men, women and
children, sacked and burned most of the houses, and carried off more
than 70 prisoners, who were subjected to the greatest cruelties and
privations, many of them dying or being tomahawked before the Canadian
settlements were reached. Cherry Valley was incorporated in 1812.



CHERSIPHRON, a Cretan architect, the traditional builder (with his son
Metagenes) of the great Ionic temple of Artemis at Ephesus set up by the
Greeks in the 6th century. Some remains of this temple were found by
J.T. Wood and brought to the British Museum. In connexion with the
pillars, which are adorned with archaic reliefs, a fragmentary
inscription has been found, recording that they were presented by King
Croesus, as indeed Herodotus informs us. This temple was burned on the
day on which Alexander the Great was born.



CHERSO, an island in the Adriatic Sea, off the east coast of Istria,
from which it is separated by the channel of Farasina. Pop. (1900) 8274.
It is situated in the Gulf of Quarnero, and is connected with the island
of Lussin, lying on the S.W. by a turn bridge over the small channel of
Ossero, and with the island of Veglia, lying on the E. by the Canale di
Mezzo. These three are the principal islands of the Quarnero group, and
form together the administrative district of Lussin in the Austrian
crownland of Istria. Cherso is an elongated island about 40 m. long, 1¼
to 7 m. wide, and has an area of 150 sq. m. It is traversed by a range
of mountains, which attain in the peak of Syss an altitude of 2090 ft.
and form natural terraces, planted with vines and olive trees, specially
in the middle and southern parts of the island. The northern part is
covered with bushes of laurel and mastic, but there are scarcely any
large trees. There is a scarcity of springs, and the houses are
generally furnished with cisterns for rain water. In the centre of the
island is an interesting lake called the Vrana or Crow's Lake, situated
at an altitude of 40 ft. above, the level of the sea, 3¾ m. long, 1 m.
wide and 184 ft. deep. This lake is in all probability fed by
subterranean sources, The chief town of the island is Cherso, situated
on the west coast. It possesses a good harbour and is provided with a
shipwright's wharf.



CHERSONESE, CHERSONESUS, or CHERRONESUS (Gr. [Greek: chersos], dry, and
[Greek: nêsos], island), a word equivalent to "peninsula." In ancient
geography the Chersonesus Thracica, Chersonesus Taurica or Scythica, and
Chersonesus Cimbrica correspond to the peninsulas of the Dardanelles,
the Crimea and Jutland; and the Golden Chersonese is usually identified
with the peninsula of Malacca. The Tauric Chersonese was further
distinguished as the Great, in contrast to the Heracleotic or Little
Chersonese at its S.W. corner, where Sevastopol now stands.

The _Tauric Chersonese_[1] (from 2nd century A.D. called Cherson) was a
Dorian colony of Heraclea in Bithynia, founded in the 5th century B.C.
in the Crimea about 2 m. S. of the modern Sevastopol. After defending
itself against the kingdom of Bosporus (q.v.), and the native Scythians
and Tauri, and even extending its power over the west coast of the
peninsula, it was compelled to call in the aid of Mithradates VI. and
his general Diophantus, c. 110 B.C., and submitted to the Pontic
dynasty. On regaining a nominal independence, it came more or less under
the Roman suzerainty. In the latter part of the 1st century A.D., and
again in the succeeding century, it received a Roman garrison and
suffered much interference in its internal affairs. In the time of
Constantine, in return for assistance against the Bosporans and the
native tribes, it regained its autonomy and received special privileges.
It must, however, have been subject to the Byzantine authorities, as
inscriptions testify to restorations of its walls by Byzantine
officials. Under Theophilus the central government sent out a governor
to take the place of the elected magistrate. Even so it seems to have
preserved a measure of self-government and may be said to have been the
last of the Greek city states. Its ruin was brought about by the
commercial rivalry of the Genoese, who forbade the Greeks to trade there
and diverted its commerce to Caffa and Sudak. Previous to this it had
been the main emporium of Byzantine commerce upon the N. coast of the
Euxine. Through it went the communications of the empire with the
Petchenegs and other native tribes, and more especially with the
Russians. The commerce of Cherson is guaranteed in the early treaties
between the Greeks and Russians, and it was in Cherson, according to Ps.
Nestor's chronicle, that Vladimir was baptized in 988 after he had
captured the city. The constitution of the city was at first democratic
under Damiorgi, a senate and a general assembly. Latterly it appears to
have become aristocratic, and most of the power was concentrated in the
hands of the first archon or Proteuon, who in time was superseded by the
strategus sent out from Byzantium. Its most interesting political
document is the form of oath sworn to by all the citizens in the 3rd
century B.C.

The remains of the city occupy a space about two-thirds of a mile long
by half a mile broad. They are enclosed by a Byzantine wall. Foundations
and considerable remains of a Greek wall going back to the 4th century
B.C. have been found beneath this in the eastern or original part of the
site. Many Byzantine churches, both cruciform and basilican, have been
excavated. The latter survived here into the 13th century when they had
long been extinct in other Greek-speaking lands. The churches were
adorned with frescoes, wall and floor mosaics, some well preserved, and
marble carvings similar to work found at Ravenna. The fact that the site
has not been inhabited since the 14th century makes it important for our
knowledge of Byzantine life. The city was used by the Romans as a place
of banishment: St Clement of Rome was exiled hither and first preached
the Gospel; another exile was Justinian II., who is said to have
destroyed the city in revenge. We have a considerable series of coins
from the 3rd century B.C. to about A.D. 200, and also some of Byzantine
date.

  See B. Koehne, _Beiträge zur Geschichte von Cherronesus in Taurien_
  (St Petersburg, 1848); art. "Chersonesos" (20) by C.G. Brandis in
  Pauly-Wissowa, _Realencydopädie_, vol. iii. 221; A. A. Bobrinskoj,
  _Chersonesus Taurica_ (St Petersburg, 1905) (Russian); V. V. Latyshev,
  _Inscrr. Orae Septentr. Ponti Euxini_, vols. i. and iv. Reports of
  excavations appear in the _Compte rendu_ of the Imperial
  Archaeological Commission of St Petersburg from 1888 and in its
  _Bulletin_. See E. H. Minns, _Scythians and Greeks_ (Cambridge, 1907).
      (E. H. M.)


FOOTNOTE:

  [1] In Pliny "Heraclea Chersonesus," probably owing to a confusion with
   the name of the mother city.



CHERTSEY, a market town in the Chertsey parliamentary division of
Surrey, England, 22 m. W.S.W. from London by the London & South-Western
railway. Pop. of urban district (1901) 12,762. It is pleasantly situated
on the right bank of the Thames, which is crossed by a bridge of seven
arches, built of Purbeck stone in 1785. The parish church, rebuilt in
1808, contains a tablet to Charles James Fox, who resided at St Anne's
Hill in the vicinity, and another to Lawrence Tomson, a translator of
the New Testament in the 17th century. Hardly any remains are left of a
great Benedictine abbey, whose buildings at one time included an area of
4 acres. They fell into almost complete decay in the 17th century, and a
"fair house" was erected out of the ruins by Sir Nicholas Carew of
Beddington. The ground-plan can be traced; the fish-ponds are complete;
and carved stones, coffins and encaustic tiles of a peculiar manufacture
are frequently exhumed. Among the abbots the most famous was John de
Rutherwyk, who was appointed in 1307, and continued, till his death in
1346, to carry on a great system of alteration and extension, which
almost made the abbey a new building. The house in which the poet Cowley
spent the last years of his life remains, and the chamber in which he
died is preserved unaltered. The town is the centre of a large
residential district. Its principal trade is in produce for the London
markets.

The first religious settlement in Surrey, a Benedictine abbey, was
founded in 666 at Chertsey (_Cerotesei, Certesey_), the manor of which
belonged to the abbot until 1539, since when it has been a possession of
the crown. In the reign of Edward the Confessor Chertsey was a large
village and was made the head of Godley hundred. The increase of
copyhold under Abbot John de Rutherwyk led to discontent, the tenants in
1381 rising and burning the rolls. Chertsey owed its importance
primarily to the abbey, but partly to its geographical position. Ferries
over the Redewynd were subjects of royal grant in 1340 and 1399; the
abbot built a new bridge over the Bourne in 1333, and wholly maintained
the bridge over the Thames when it replaced the 14th century ferry. In
1410 the king gave permission to build a bridge over the Redewynd. As
the centre of an agricultural district the markets of Chertsey were
important and are still held. Three days' fairs were granted to the
abbots in 1129 for the feast of St Peter ad Vincula by Henry III. for
Holy Rood day; in 1282 for Ascension day; and a market on Mondays was
obtained in 1282. In 1590 there were many poor, for whose relief
Elizabeth gave a fair for a day in Lent and a market on Thursdays. These
fairs still survive.

  See Lucy Wheeler, _Chertsey Abbey_ (London, 1905); _Victoria County
  History, Surrey_.



CHERUBIM, the Hebrew plural of "cherub" (_kerub_), imaginary
winged animal figures of a sacred character, referred to in the
description of Solomon's temple (1 Kings vi. 23-35, vii. 29, viii. 6,
7), and also in that of the ark of the tabernacle (Ex. xxv. 18-22, xxvi.
1, 31, xxxvii. 7-9). The cherub-images, where such occur, represent to
the imagination the supernatural bearers of Yahweh's throne or chariot,
or the guardians of His abode; the cherub-carvings at least symbolize
His presence, and communicate some degree of His sanctity. In Gen. iii.
24 the cherubim are the guards of Paradise; Ezek. xxviii. 14, 16 cannot
be mentioned here, the text being corrupt. We also find (1 Sam. iv. 4; 2
Sam. vi. 2) as a divine title "that sitteth upon the cherubim"; here it
is doubted whether the cherubim are the material ones in the temple, or
those which faith assumes and the artist tries to represent--the
supernatural steeds upon which Yahweh issues forth to interfere in human
affairs. In a poetic theophany (Ps. xviii. 10) we find "upon a cherub"
parallel to "upon the wings of the wind" (cp. Isa. xix. 1; Ps. civ. 3).
One naturally infers from this that the "cherub" was sometimes viewed as
a bird. For the clouds, mythologically, are birds. "The Algonkins say
that birds always make the winds, that they create the waterspouts, and
that the clouds are the spreading and agitation of their wings." "The
Sioux say that the thunder is the sound of the cloud-bird flapping his
wings." If so, Ps. xviii. 10 is a solitary trace of the archaic view of
the cherub. The bird, however, was probably a mythic, extra-natural
bird. At any rate the cherub was suggested by and represents the
storm-cloud, just as the sword in Gen. iii. 24 corresponds to the
lightning. In Ezek. i. the four visionary creatures are expressly
connected with a storm-wind, and a bright cloud (ver. 4). Elsewhere
(xli. 18) the cherub has two faces (a man's and a bird's), but in i. 10
and x. 14 each cherub has four faces, a view tastefully simplified in
the Johannine Apocalypse (Rev. iv. 7).

It is best, however, to separate Ezekiel from other writers, since he
belongs to what may be called a great mythological revival. Probably his
cherubim are a modification of older ones, which may well have been of a
more sober type. His own accounts, as we have seen, vary. Probably the
cherub has passed through several phases. There was a mythic
bird-cherub, and then perhaps a winged animal-form, analogous to the
winged figures of bulls and lions with human faces which guarded
Babylonian and Assyrian temples and palaces. Another analogy is
furnished by the winged genii represented as fertilizing the sacred
tree--the date-palm (Tylor); here the body is human, though the face is
sometimes that of an eagle. It is perhaps even more noteworthy that
figures thought to be cherubs have been found at Zenjirli, within the
ancient North Syrian kingdom of Ya'di (see Jeremias, _Das Alte Testament
im Lichte des Alten Orients_, pp. 350 f.); we may combine this with the
fact that one of the great gods of this kingdom was called Rakab'el or
Rekub'el (also perhaps Rakab or Rekub). A Sabaean (S. Arabian) name
Karab'el also exists. The kerubim might perhaps be symbolic
representatives of the god Rakab'el or Rekub'el, probably equivalent
to Hadad, whose sacred animal was the bull. That the figures symbolic of
Rakab or Hadad were compounded or amalgamated by the Israelites with
those symbolic of Nergal (the lion-god) and Ninib (the eagle-god), is
not surprising.

  See further "Cherubim," in _Ency. Bib._ and _Hast. D.B._; Cheyne,
  _Genesis_; Tylor, _Proc. Soc. Bibl. Arch._ xii. 383 ff.; Zimmern, _Die
  Keilinschriften und das Alte Testament_, pp. 529 f., 631 f.; Dibelius,
  _Die Lade Jahves_ (1906), pp. 72-86. (T.K.C.)



CHERUBINI, MARIA LUIGI CARLO ZENOBIO SALVATORE (1760-1842), Italian
musical composer, was born at Florence on the 14th of September 1760,
and died on the 15th of March 1842 in Paris. His father was accompanist
(_Maestro al Cembalo_) at the Pergola theatre. Cherubini himself, in the
preface of his autograph catalogue of his own works, states, "I began to
learn music at six and composition at nine, the former from my father,
the latter from Bartolomeo and Alessandro Felici, and, after their
death, from Bizzarri and J Castrucci." By the time he was sixteen he had
composed a great deal of church music, and in 1777 he went to Bologna,
where for four years he studied under Sarti. This deservedly famous
master well earned the gratitude which afterwards impelled Cherubini to
place one of his double choruses by the side of his own _Et Vitam
Venturi_ as the crown of his _Treatise on Counterpoint and Fugue_,
though the juxtaposition is disastrous for Sarti. But besides grounding
Cherubini in the church music for which he had early shown so special a
bent, Sarti also trained him in dramatic composition; sometimes, like
the great masters of painting, entrusting his pupil with minor parts of
his own works. From 1780 onwards for the next fourteen years dramatic
music occupied Cherubini almost entirely. His first complete opera,
_Quinto Fabio_, was produced in 1780, and was followed in 1782 by
_Armida, Adriano in Siria_, and other works. Between 1782 and 1784 the
successful production of five operas in four different towns must have
secured Cherubini a dignified position amongst his Italian
contemporaries; and in 1784 he was invited to London to produce two
works for the Italian opera there, one of which, _La Finta Frincipessa_,
was favourably received, while the other, _Giulio Sabino_, was,
according to a contemporary witness, "murdered" by the critics.

In 1786 he left London for Paris, which became his home after a visit to
Turin in 1787-1788 on the occasion of the production there of his
_Ifigenia in Aulide_. With Cherubini, as with some other composers first
trained in a school where the singer reigned supreme, the influence of
the French dramatic sensibility prpved decisive, and his first French
opera, _Démophon_ (1788), though not a popular success, already marks a
departure from the Italian style, which Cherubini still cultivated in
the pieces he introduced into the works of Anfossi, Paisiello and
Cimarosa, produced by him as director of the Italian opera in Paris
(established in 1789). As in Paris Gluck realized his highest ambitions,
and even Rossini awoke to a final effort of something like dramatic life
in _Guillaume Tell_, so in Paris Cherubini became a great composer. If
his melodic invention had been as warm as Gluck's, his immensely
superior technique in every branch of the art would have made him one of
the greatest composers that ever lived. But his personal character shows
in quaint exaggeration the same asceticism that in less sour and more
negative form deprives even his finest music of the glow of that lofty
inspiration that fears nothing.

With _Lodoiska_ (1791) the series of Cherubim's masterpieces begins, and
by the production of _Médée_ (1797) his reputation was firmly
established. The success of this sombre classical tragedy, which shows
Cherubini's genius in its full power, is an honour to the Paris public.
If Cherubini had known how to combine his high ideals with an urbane
tolerance of the opinions of persons of inferior taste, the severity of
his music would not have prevented his attaining the height of
prosperity. But Napoleon Bonaparte irritated him by an enthusiasm for
the kind of Italian music against which his whole career, from the time
he became Sarti's pupil, was a protest. When Cherubini said to Napoleon,
"Citoyen Général, I perceive that you love only that music which does
not prevent you thinking of your politics," he may perhaps have been as
firmly convinced of his own conciliatory manner as he was when many
years afterwards he "spared the feelings" of a musical candidate by
"delicately" telling him that he had "a beautiful voice and great
musical intelligence, but was too ugly for a public singer." Napoleon
seems to have disliked opposition in music as in other matters, and the
academic offices held by Cherubini under him were for many years far
below his deserts. But though Napoleon saw no reason to conceal his
dislike of Cherubini, his appointment of Lesueur in 1804 as his
chapelmaster must not be taken as an evidence of his hostility. Lesueur
was not a great genius, but, although recommended for the post by the
retiring chapelmaster, Paesiello (one of Napoleon's Italian favourites),
he was a very meritorious and earnest Frenchman whom the appointment
saved from starvation. Cherubini's creative genius was never more
brilliant than at this period, as the wonderful two-act ballet,
_Anacreon_, shows; but his temper and spirits were not improved by a
series of disappointments which culminated in the collapse of his
prospects of congenial success at Vienna, where he went in 1805 in
compliance with an invitation to compose an opera for the Imperial
theatre. Here he produced, under the title of _Der Wasserträger_, the
great work which, on its first production on the 7th of January 1801 (26
_Nivôse, An_8) as _Les Deux Journées_, had thrilled Paris with the
accents of a humanity restored to health and peace. It was by this time
an established favourite in Austria. On the 25th of February Cherubini
produced _Faniska_, but the war between Austria and France had broken
out immediately after his arrival, and public interest in artistic
matters was checked by the bombardment and capitulation of Vienna.
Though the meeting between Cherubini and the victorious Napoleon was not
very friendly, he was called upon to direct the music at Napoleon's
soirées at Schönbrunn. But this had not been his object in coming to
Vienna, and he soon returned to a retired and gloomy life in Paris.

His stay at Vienna is memorable for his intercourse with Beethoven, who
had a profound admiration for him which he could neither realize nor
reciprocate. It is too much to expect that the mighty genius of
Beethoven, which broke through all rules in vindication of the
principles underlying them, would be comprehensible to a mind like
Cherubini's, in which, while the creative faculties were finely
developed, the critical faculty was atrophied and its place supplied by
a mere disciplinary code inadequate even as a basis for the analysis of
his own works. On the other hand, it would be impossible to exaggerate
the influence _Les Deux Journées_ had on the lighter parts of
Beethoven's _Fidelio_. Cherubini's librettist was also the author of the
libretto from which _Fidelio_ was adapted, and Cherubini's score was a
constant object of Beethoven's study, not only before the production of
the first version of _Fidelio_, as _Leonore_, but also throughout
Beethoven's life. Cherubini's record of his impressions of Beethoven as
a man is contained in the single phrase, "Il était toujours brusque,"
which at least shows a fine freedom from self-consciousness on the part
of the man whose only remark on being told of the death of Brod, the
famous oboist, was, "Ah, he hadn't much tone" ("Ah, petit son"). Of the
overture to _Leonore_ Cherubini only remarked that he could not tell
what key it was in, and of Beethoven's later style he observed, "It
makes me sneeze." Beethoven's brusqueness, notorious as it was, did not
prevent him from assuring Cherubini that he considered him the greatest
composer of the age and that he loved him and honoured him. In 1806
Haydn had just sent out his pathetic "visiting card" announcing that he
was past work; Weber was still sowing wild oats, and Schubert was only
nine years old. We need not, then, be surprised at Beethoven's judgment.
And though we must regret that Cherubini's disposition prevented him
from understanding Beethoven, it would be by no means true to say that
he was uninfluenced at least by the sheer grandeur of the scale which
Beethoven had by that time established as the permanent standard for
musical art. Grandeur of proportion was, in fact, eminently
characteristic of both composers, and the colossal structure of such a
movement as the duet _Perfides ennemis_ in _Médée_ is almost
inconceivable without the example of Beethoven's C minor trio, op. 1,
No. 3, published two years before it; while the cavatina _Eterno iddio_
in _Faniska_ is not only worthy of Beethoven but surprisingly like him
in style.

After Cherubini's disappointing visit to Vienna he divided his time
between teaching at the conservatoire and cutting up playing-cards into
figures and landscapes, which he framed and placed round the walls of
his study. Not until 1809 was he aroused from this morbid indolence. He
was staying in retirement at the country seat of the prince de Chimay,
and his friends begged him to write some music for the consecration of a
church there. After persistent refusals he suddenly surprised them with
a mass in F for three-part chorus and orchestra. With this work the
period of his great church music may be said to begin; although it was
by no means the end of his career as an opera writer, which, in fact,
lasted as late as his seventy-third year. This third period is also
marked by some not unimportant instrumental compositions. An early event
in the annals of the Philharmonic Society was his invitation to London
in 1815 to produce a symphony, an overture and a vocal piece. The
symphony (in D) was afterwards arranged with a new slow movement as the
string quartet in C (1829), a fact which, taken in connexion with the
large scale of the work, illustrates Cherubini's deficient sense of
style in chamber music. Nevertheless all the six string quartets written
between 1814 and 1837 are interesting works performed with success at
the present day, though the last three, discovered in 1880, are less
satisfactory than the earlier ones. The requiem in C minor (1817) caused
Beethoven to declare that if he himself ever wrote a requiem Cherubini's
would be his model.

At the eleventh hour Cherubini received recognition from Napoleon, who,
during the Hundred Days, made him chevalier of the Legion of Honour.
Then, with the restoration of the Bourbons, the very fact that Cherubini
had not been _persona grata_ with Napoleon brought him honour and
emoluments. He was appointed, jointly with Lesueur, as composer and
conductor to the Chapel Royal, and in 1822 he obtained the permanent
directorship of the conservatoire. This brought him into contact, for
the most part unfriendly, with all the most talented musicians of the
younger generation. It is improbable that Berlioz would have been an
easy subject for the wisest and kindest of spiritual guides; but no
influence, repellent or attractive, could have been more disastrous for
that passionate, quick-witted and yet eminently puzzle-headed mixture of
Philistine and genius, than the crabbed old martinet whose regulations
forbade the students access to Gluck's scores in the library, and whose
only theory of art (as distinguished from his practice) is accurately
formulated in the following passage from Berlioz's _Grande Traité de
l'instrumentation et d'orchestration_: "It was no use for the modern
composer to say, 'But do just listen! See how smoothly this is
introduced, how well motived, how deftly connected with the context, and
how splendid it sounds!' He was answered, 'That is not the point. This
modulation is forbidden; therefore it must not be made.'" The lack of
really educative teaching, and the actual injustice for which
Cherubini's disciplinary methods were answerable, did much to weaken
Berlioz's at best ill-balanced artistic sense, and it is highly probable
that, but for the kindliness and comparative wisdom of his composition
master, Lesueur, he would have broken down from sheer lack of any
influence which could command the respect of an excitable youth starving
in the pursuit of a fine art against the violent opposition of his
family. Only when Mendelssohn, at the age of seventeen, visited Paris in
1825, did Cherubini startle every one by praising a young composer to
his face.

In 1833 Cherubini produced his last work for the stage, _Ali Baba_,
adapted (with new and noisy features which excited Mendelssohn's
astonished disgust) from a manuscript opera, _Koukourgi_, written forty
years earlier. It is thus, perhaps, not a fair illustration of the
vigour of his old age; but the requiem in D minor (for male voices),
written in 1836, is one of his greatest works, and, though not actually
his last composition, is a worthy close to the long career of an artist
of high ideals who, while neither by birth nor temperament a Frenchman,
must yet be counted with a still greater foreigner, Gluck, as the glory
of French classical music. In this he has no parallel except his friend
and contemporary, Méhul, to whom he dedicated _Médée_, and who dedicated
to him the beautiful Ossianic one-act opera _Uthal_. The direct results
of his teaching at the conservatoire were the steady, though not as yet
unhealthy, decline of French opera into a lighter style, under the
amiable and modest Boieldieu and the irresponsible and witty Auber; for,
as we have seen, Cherubini was quite incapable of making his ideals
intelligible by any means more personal than his music; and the crude
grammatical rules which he mistook for the eternal principles of his own
and of all music had not the smallest use as a safeguard against
vulgarity and pretentiousness.

Lest the passage above quoted from Berlioz should be suspected of bias
or irrelevance, we cite a few phrases from Cherubini's _Treatise on
Counterpoint and Fugue_, of which, though the letter-press is by his
favourite pupil, Halévy, the musical examples and doctrine are beyond
suspicion his own. Concerning the 16th-century idiom, incorrectly but
generally known as the "changing note" (an idiom which to any musical
scholar is as natural as "attraction of the relative" is to a Greek
scholar), Cherubini remarks, "No tradition gives us any reason why the
classics thus faultily deviated from the rule." Again, he discusses the
use of "suspensions" in a series of chords which without them would
contain consecutive fifths, and after making all the observations
necessary for the rational conclusion that the question whether the
fifths are successfully disguised or not depends upon the beauty and
force of the suspensions, he merely remarks that "The opinion of the
classics appears to me erroneous, notwithstanding that custom has
sanctioned it, for, on the principle that the discord is a mere
suspension of the chord, it should not affect the nature of the chord.
But since the classics have pronounced judgment we must of course
submit." In the whole treatise not one example is given from Palestrina
or any other master who handled as a living language what are now the
forms of contrapuntal discipline. As a dead language Cherubini brought
counterpoint up to date by abandoning the church modes; but in true
severity of principle, as in educational stimulus, his treatise shows a
deplorable falling off from the standard set a hundred years before in
Fux's _Gradus ad Panassum_ with its delightful dialogues between master
and pupil and its continual appeal to artistic experience. Whatever may
have been Cherubini's success in imparting facility and certainty to his
light-hearted pupils who established 19th-century French opera as a
refuge from the terrors of serious art, there can be no doubt that his
career as a teacher did more harm than good. In it the punishment drill
of an incompetent schoolmaster was invested with the authority of a
great composer, and by it the false antithesis between the "classical"
and the "romantic" was erected into a barrier which many critics still
find an insuperable obstacle to the understanding of the classical
spirit. And yet as a composer Cherubini was no pseudo-classic but a
really great artist, whose purity of style, except at rare moments, just
failed to express the ideals he never lost sight of, because in his love
of those ideals there was top much fear.

  His principal works are summarized by Fetis as thirty-two operas,
  twenty-nine church compositions, four cantatas and several
  instrumental pieces, besides the treatise on counterpoint and fugue.

  Good modern full scores of the two Requiems and of _Les Deux
  Journées_(the latter unfortunately without the dialogue, which,
  however, is accessible in its fairly good German translation in the
  _Reclam Bibliolhek_), and also of ten opera overtures, are current in
  the Peters edition. Vocal scores of some of the other operas are not
  difficult to get. The great _Credo_ is in the Peters edition, but is
  becoming scarce. The string quartets are in Payne's _Miniature
  Scores._It is very desirable that the operas, from _Démophon_ onwards,
  should be republished in full score.

  See also E. Bellasis, _Cherubini_ (1874); and an article with personal
  reminiscences by the composer Ferdinand Hiller, in _Macmillan's
  Magazine_(1875). A complete catalogue of his compositions (1773-1841)
  was edited by Bottée du Toulmon.    (D. F. T.)



CHÉRUEL, PIERRE ADOLPHE (1800-1891), French historian, was born at Rouen
on the 17th of January 1809. He was educated at the École Normale
Supérieure, and became a fellow (_agrégé_) in 1830. His early studies
were devoted to his native town. His _Histoire de Rouen sous la
domination anglaise au XVe siecle_(1840) and _Histoire de Rouen pendant
l'époque comunale, 1150-1382_(Rouen, 1843-1844), are meritorious
productions for a time when the archives were neither inventoried nor
classified, and contain useful documents previously unpublished. His
theses for the degree of doctor, _De l'administration de Louis XIV
d'après les Mémoires inédits d'Olivier d'Ormesson_ and _De Maria Stuarta
et Henrico III_. (1849), led him to the study of general history. The
former was expanded afterwards under the title _Histoire de
l'administration monarchique en France depuis l'avènement de
Philippe-Auguste jusqu'à la mort de Louis XIV_(1855), and in 1855 he
also published his _Dictionnaire historique des institutions, moeurs et
coutumes de la France_, of which many editions have appeared. These
works may still be consulted for the 17th century, the period upon which
Chéruel concentrated all his scientific activity. He edited successively
the _Journal d'Olivier Lefèvre d'Ormesson_(1860-1862), interesting for
the history of the parlement of Paris during the minority of Louis XIV.;
_Lettres du cardinal Mazarin pendant son ministère_ (6 vols.,
1870-1891), continued by the vicomte G. d'Avenel; and _Memoires du duc
de Saint-Simon_, published for the first time according to the original
MSS. (2 editions, 1856-1858 and 1878-1881). To Saint-Simon also he
devoted two critical studies, which are acute but not definitive:
_Saint-Simon considéré comme historien de Louis XIV_ (1865) and _Notice
sur la vie et sur les mémoires du duc de Saint-Simon_(1876). The latter
may be considered as an introduction to the famous _Mémoires_. Among his
later writings may be mentioned the _Histoire de la France pendant la
minorité de Louis XIV_ (4 vols., 1880) and _Histoire de la France sous
le ministère de Mazarin_ (3 vols., 1882-1883). These two works are
valuable for abundance of facts, precision of details, and clear and
intelligent arrangement, but are characterized by a slightly frigid
style. In their compilation Chéruel used a fair number of unpublished
documents. To the student of the second half of the 17th century in
France the works of Chéruel are a mine of information. He died in Paris
on the 1st of May 1891.



CHERUSCI, an ancient German tribe occupying the basin of the Weser to
the north of the Chatti. Together with the other tribes of western
Germany they submitted to the Romans in 11-9 B.C., but in A.D. 9
Arminius, one of their princes, rose in revolt, and defeated and slew
the Roman general Quintilius Varus with his whole army. Germanicus
Caesar made several unsuccessful attempts to bring them into subjection
again. By the end of the 1st century the prestige of the Cherusci had
declined through unsuccessful warfare with the Chatti. Their territory
was eventually occupied by the Saxons.

  Tacitus, _Annals_, i.2, 11, 12, 13; _Germania_, 36; Strabo, p. 291 f.;
  E. Devrient, in _Neue Jahrb. f. d. klass. Alter_. (1900), p. 517.



CHESELDEN, WILLIAM (1688-1752), English surgeon, was born at Somerby,
Leicestershire, on the 19th of October 1688. He studied anatomy in
London under William Cowper (1666-1709), and in 1713 published his
_Anatomy of the Human Body_, which achieved great popularity and went
through thirteen editions. In 1718 he was appointed an assistant surgeon
at St Thomas's hospital (London), becoming full surgeon in the following
year, and he was also chosen one of the surgeons to St George's hospital
on its foundation in 1733. He retired from St Thomas's in 1738, and died
at Bath on the 10th of April 1752. Cheselden is famous for his "lateral
operation for the stone," which he first performed in 1727. He also
effected a great advance in ophthalmic surgery by his operation of
iridectomy, described in 1728, for the treatment of certain forms of
blindness by the production of an "artificial pupil." He attended Sir
Isaac Newton in his last illness, and was an intimate friend of
Alexander Pope and of Sir Hans Sloane.



CHESHAM, a market town in the Aylesbury parliamentary division of
Buckinghamshire, England, 26 m. W.N.W. of London by the Metropolitan
railway. Pop. of urban district (1901) 7245. It is pleasantly situated
in the narrow valley of the river Chess, closely flanked by low wooded
hills. The church of St Mary is cruciform and mainly Perpendicular. Some
ancient frescoes and numerous monuments are preserved. All sorts of
small dairy utensils, chairs, malt-shovels, &c., are made of beech, the
growth of which forms a feature of the surrounding country. Shoemaking
is also carried on. In Waterside hamlet, adjoining the town, are
flour-mills, duck farms, and some of the extensive watercress beds for
which the Chess is noted, as it is also for its trout-fishing.



CHESHIRE, a north-western county of England, bounded N. by Lancashire,
N.E. by Yorkshire and Derbyshire, S.E. by Staffordshire, S. by
Shropshire, W. by Denbighshire and Flint, and N.W. by the Irish Sea. Its
area is 1027.8 sq. m. The coast-line is formed by the estuaries of the
Dee and the Mersey, which are separated by the low rectangular peninsula
of Wirral. The estuary of the Dee is dry at low tide on the Cheshire
shore, but that of the Mersey bears upon its banks the ports of
Liverpool (in Lancashire) and Birkenhead (on the Wirral shore). The Dee
forms a great part of the county boundary with Denbighshire and Flint,
and the Mersey the boundary along the whole of the northern side. The
principal river within the county is the Weaver, which crosses it with a
north-westerly course, and, being joined by the Dane at Northwich,
discharges into the estuary of the Mersey south of Runcorn. The surface
of Cheshire is mostly low and gently undulating or flat; but the broken
line of the Peckforton hills, seldom exceeding 600 ft. in height, runs
north and south flanking the valley of the Weaver on the west. A low
narrow gap in these hills is traversed by the small river Gowy, which
rises to the east but has the greater part of its course to the west of
them. Commanding this gap on the west, the Norman castle of Beeston
stands on an isolated eminence. The northern part of the hills coincides
approximately with the district still called Delamere Forest, formerly a
chase of the earls of Chester, and finally disforested in 1812. In
certain sequestered parts the forest has not wholly lost its ancient
character. On the east Cheshire includes the western face of the broad
belt of high land which embraces the Peak district of Derbyshire; these
hills rise sharply to the east of Congleton, Macclesfield and Hyde,
reaching a height of about 1800 ft. within Cheshire. Distributed over
the county, but principally in the eastern half, are many small lakes or
meres, such as Combermere, Tatton, Rostherne, Tabley, Doddington,
Marbury and Mere, and it was a common practice among the gentry of the
county to build their mansions on the banks of these waters. The meres
form one of the most picturesque features of the county.

  _Geology._--With the exception of a small area of Carboniferous rocks
  on the eastern border, and a small patch of Lower Lias near Audlem,
  the whole country is occupied by Triassic strata. The great central
  plain is covered by red and mottled Keuper Marls. From these marls
  salt is obtained; there are many beds of rock-salt, mostly thin; two
  are much thicker than the others, being from 75 ft. to over 100 ft.
  thick. Thin beds and veins of gypsum are common in the marls. The
  striking features of the Peckforton Hills are due to the repeated
  faulting of the Lower Keuper Sandstone, which lies upon beds of Bunter
  Sandstone. Besides forming this well-marked ridge, the Lower Keuper
  Sandstones or "Waterstones" form several ridges north-west of
  Macclesfield and appear along most of the northern borders of the
  county and in the neighbourhood of New Brighton and Birkenhead. The
  Lower Keuper Sandstone is quarried near the last-named place, also at
  Storeton, Delamere and Manley. This is a good building stone and an
  important water-bearing stratum; it is often ripple-marked, and bears
  the footprints of the _Cheirotherium_. At Alderley Edge ores of
  copper, lead and cobalt are found. West of the Peckforton ridge,
  Bunter Sandstones and pebble beds extend to the border. They also form
  low foothills between Cheadle and Macclesfield. They fringe the
  northern boundary and appear on the south-eastern boundary as a narrow
  strip of hilly ground near Woore. The oldest rock exposed in the
  county is the small faulted anticline of Carboniferous limestone at
  Astbury, followed in regular succession eastward by the shale, and
  thin limestones and sandstones of the Pendleside series. These rocks
  extend from Congleton Edge to near Macclesfield, where the outcrop
  bends sharply eastward and runs up the Goyt valley. Some hard
  quartzites in the Pendleside series, known locally as "Crowstones,"
  have contributed to the formation of the high Bosley Min and
  neighbouring hills. East of Bosley Min, on either side of the Goyt
  valley, are the Millstone Grits and Shales, forming the elevated
  moorland tracts. Cloud Hill, a striking feature near Congleton, is
  capped by the "Third Grit," one of the Millstone Grit series. From
  Macclesfield northward through Stockport is a narrow tongue of Lower
  and Middle Coal-Measures--an extension of the Lancashire coalfield.
  Coal is mined at Neston in the Wirral peninsula from beneath the
  Trias; it is a connecting link between the Lancashire and Flintshire
  coalfields. Glacial drift is thickly spread over all the lower ground;
  laminated red clays, stiff clay with northern erratics and lenticular
  sand masses with occasional gravels, are the common types. At Crewe
  the drift is over 400 ft. thick. Patches of Drift sand, with marine
  shells, occur on the high ground east of Macclesfield at an elevation
  of 1250 ft.

_Agriculture and Industries._--The climate is temperate and rather damp;
the soil is varied and irregular, but a large proportion is a
thin-skinned clay. More than four-fifths of the total area is under
cultivation. The crop of wheat is comparatively insignificant; but a
large quantity of oats is grown, and a great proportion of the
cultivated land is in permanent pasture. The vicinity of such populous
centres as Liverpool and Manchester, as well as the several large towns
within the county, makes cattle and dairy-farming profitable. Cheese of
excellent quality is produced, the name of the county being given to a
particular brand (see DAIRY). Potatoes are by far the most important
green crop. Fruit-growing is carried on in some parts, especially the
cultivation of stone fruit and, among these, damsons; while the
strawberry beds near Farndon and Holt are celebrated. In the first half
of the 19th century the condition of agriculture in Cheshire was
notoriously backward; and in 1865-1866 the county suffered with especial
severity from a visitation of cattle plague. The total loss of stock
amounted to more than 66,000 head, and it was necessary to obtain from
the Treasury a loan of £270,000 on the security of the county rate, for
purposes of relief and compensation. The cheese-making industry
naturally received a severe blow, yet to agriculture at large an
ultimate good resulted as the possibility and even the necessity of new
methods were borne in upon the farmers.

The industries of the county are various and important. The manufacture
of cotton goods extends from its seat in Lancashire into Cheshire, at
the town of Stockport and elsewhere in the north-east. Macclesfield and
Congleton are centres of silk manufacture. At Crewe are situated the
great workshops of the London & North-Western railway company, the
institution of which actually brought the town in to being. Another
instance of the modern creation of a town by an individual industrial
corporation is seen in Port Sunlight on the Mersey, where the soap-works
of Messrs Lever are situated. On the Mersey there are shipbuilding
yards, and machinery and iron works. Other important manufactures are
those of tools, chemicals, clothing and hats, and there are printing,
bleaching and dye works, and metal foundries. Much sandstone is
quarried, but the mineral wealth of the county lies in coal and salt.
The second is a specially important product. Some rock-salt is obtained
at Northwich and Winsford, but most of the salt is extracted from brine
both here and at Lawton, Wheelock and Middlewich. At Northwich and other
places in the locality curious accidents frequently occur owing to the
sinking of the soil after the brine is pumped out; walls crack and
collapse, and houses are seen leaning far out of the perpendicular. A
little copper and lead are found.

_Communications._--The county is well served with railways. The main
line of the London & North-Western railway, passing north from Crewe to
Warrington in Lancashire, serves no large town, but from Crewe branches
diverge fanwise to Manchester, Chester, North Wales and Shrewsbury. The
Great Western railway, with a line coming northward from Wrexham,
obtains access through Cheshire to Liverpool and Manchester. These two
companies jointly work the Birkenhead railway from Chester to
Birkenhead. The heart of the county is traversed by the Cheshire Lines,
serving the salt district, and reaching Chester from Manchester by way
of Delamere Forest. In the east the Midland and Great Central systems
enter the county, and the North Staffordshire line serves Macclesfield.
The Manchester, South Junction & Altrincham and the Wirral railways are
small systems serving the localities indicated by their names. The river
Weaver is locked as far up as Winsford, and the transport of salt is
thus expedited. The profits of the navigation, which was originally
undertaken in 1720 by a few Cheshire squires, belong to the county, and
are paid annually to the relief of the county rates. In the salt
district through which the Weaver passes subsidence of the land has
resulted in the formation of lakes of considerable extent, which act as
reservoirs to supply the navigation. There are further means of inland
navigation by the Grand Trunk, Shropshire Union and other canals, and
many small steamers are in use. The Manchester Ship Canal passes through
a section of north Cheshire, being entered from the estuary of the
Mersey by locks near Eastham, and following its southern shore up to
Runcorn, after which it takes a more direct course than the river.

_Population and Administration._--The ancient county, which is a county
palatine, has an area of 657,783 acres, with a population in 1891 of
730,058 and in 1901 of 815,099. Cheshire has been described as a suburb
of Liverpool, Manchester and the Potteries of Staffordshire, and many of
those whose business lies in these centres have colonized such districts
as Bowdon, Alderley, Sale and Marple near Manchester, the Wirral, and
Alsager on the Staffordshire border, until these localities have come to
resemble the richer suburban districts of London. On the short seacoast
of the Wirral are found the popular resorts of New Brighton and Hoylake.
This movement and importance of its industries have given the county a
vast increase of population in modern times. In 1871 the population was
561,201; from 1801 until that year it had increased 191%. The area of
the administrative county is 654,825 acres. The county contains 7
hundreds. The municipal boroughs are Birkenhead (pop. 110,915), Chester
(38,309), Congleton (10,707), Crewe (42,074), Dukinfield (18,929), Hyde
(32,766), Macclesfield (34,624), Stalybridge (27,673), Stockport
(92,832). Chester, the county town, is a city, county of a city, and
county borough, and Birkenhead and Stockport are county boroughs. The
other urban districts with their populations are as follows:--

    Alderley Edge (a)              2,856
    Alsager                        2,597
    Altrincham (a)                16,831
    Ashton-upon-Mersey (a)         5,563
    Bollington (a)                 5,245
    Bowdon (a)                     2,788
    Bredbury and Romiley (a)       7,087
    Bromborough (b)                1,891
    Buglawton (Congleton)          1,452
    Cheadle and Gatley (a)         7,916
    Compstall (a)                    875
    Ellesmere Port and Whitby (b)  4,082
    Hale (a)                       4,562
    Handforth (a)                    911
    Hazel Grove and Bramhall (a)   7,934
    Higher Bebington (b)           1,540
    Hollingworth (a)               2,447
    Hoole (Chester)                5,341
    Hoylake and West Kirkby (b)   10,911
    Knutsford (a)                  5,172
    Lower Bebington (b)            8,398
    Lymm (a)                       4,707
    Marple (a)                     5,595
    Middlewich                     4,669
    Mottram-in-Longdendale (a)     3,128
    Nantwich                       7,722
    Neston and Parkgate (b)        4,154
    Northwich                     17,611
    Runcorn                       16,491
    Sale (a)                      12,088
    Sandbach                       5,558
    Tarporley                      2,644
    Wallasey (b)                  53,579
    Wilmslow (a)                   7,361
    Winsford                      10,382
    Yeardsley-cum-Whaley (a)       1,487

  Of the townships in this table, those marked (a) are within a radius
  of about 15 m. from Manchester (Knutsford being taken as the limit),
  while those marked (b) are in the Wirral. The localities of densest
  population are thus clearly illustrated.

The county is in the North Wales and Chester circuit, and assizes are
held at Chester. It has one court of quarter sessions, and is divided
into fourteen petty sessional divisions. The boroughs already named,
excepting Dukinfield, have separate commissions of the peace, and
Birkenhead and Chester have separate courts of quarter sessions. There
are 464 civil parishes. Cheshire is almost wholly in the diocese of
Chester, but small parts are in those of Manchester, St Asaph or
Lichfield. There are 268 ecclesiastical parishes or districts wholly or
in part within the county. There are eight parliamentary divisions,
namely, Macclesfield, Crewe, Eddisbury, Wirral, Knutsford, Altrincham,
Hyde and Northwich, each returning one member; the county also includes
the parliamentary borough of Birkenhead returning one member, and parts
of the borough of Stockport, which returns two members, and of
Ashton-under-Lyne, Chester, Stalybridge, and Warrington, which return
one member each.

_History._--The earliest recorded historical fact relating to the
district which is now Cheshire is the capture of Chester and destruction
of the native Britons by the Northumbrian king Æthelfrith about 614.
After a period of incessant strife between the Britons and their Saxon
invaders the district was subjugated by Ecgbert in 830 and incorporated
in the kingdom of Mercia. During the 9th century. Æthelwulf held his
parliament at Chester, and received the homage of his tributary kings
from Berwick to Kent, and in the 10th century Æthelflæd rebuilt the
city, and erected fortresses at Eddisbury and Runcorn. Edward the Elder
garrisoned Thelwall and strengthened the passages of the Mersey and the
Irwell. On the splitting up of Mercia in the 10th century the dependent
districts along the Dee were made a shire for the fortress of Chester.
The shire is first mentioned in the Abingdon _Chronicle_, which relates
that in 980 Cheshire was plundered by a fleet of Northmen. At the time
of the Domesday Survey the county was divided into twelve hundreds,
exclusive of the six hundreds between the Ribble and the Mersey, now
included in Lancashire, but then a part of Cheshire. These divisions
have suffered great modification, both in extent and in name, and of the
seven modern hundreds Bucklow alone retains its Domesday appellation.
The hundreds of Atiscross and Exestan have been transferred to the
counties of Flint and Denbigh, with the exception of a few townships now
in the hundred of Broxton. The prolonged resistance of Cheshire to the
Conqueror was punished by ruthless harrying and sweeping confiscations
of property, and no Englishman retained estates of importance after the
Conquest. In order that the shire might be relieved of all obligations
beyond the ever-pressing necessity of defending its borders against the
inroads of hostile neighbours, it was constituted a county palatine
which the earl of Chester "held as freely by his sword as the king held
England by his crown." The County had its independent parliament
consisting of the barons and clergy, and courts, and all lands except
those of the bishop were held of the earl. The court of exchequer was
presided over by a chamberlain, a vice-chamberlain, and a baron of the
exchequer. It was principally a court of revenue, but probably a court
of justice also, before that of the justiciary was established, and had
besides the functions of a chancery court, with an exclusive
jurisdiction in equity. Other officers of the palatinate were the
constable, high-steward and the Serjeants of the peace and of the
forests. The abbots of St Werburgh and Combermere and all the eight
barons held courts, in any of which cases of capital felony might be
tried.

During the 12th and 13th centuries the county was impoverished by the
constant inroads of the Welsh. In 1264 the castle and city of Chester
were granted to Simon de Montfort, and in 1267 the treaty of Shrewsbury
procured a short interval of peace. Richard II., in return for the loyal
support furnished him by the county, made it a principality, but the act
was revoked in the next reign. In 1403 Cheshire was the headquarters of
Hotspur, who roused the people by telling them that Richard II. was
still living. At the beginning of the Wars of the Roses Margaret
collected a body of supporters from among the Cheshire gentry, and
Lancastrian risings occurred as late as 1464. At the time of the Civil
War feeling was so equally divided that an attempt was made to form an
association for preserving internal peace. In 1643, however, Chester was
made the headquarters of the royalist forces, while Nantwich was
garrisoned for the parliament, and the county became the scene of
constant skirmishes until the surrender of Chester in 1646 put an end to
the struggle.

From the number of great families with which it has been associated
Chester has been named "the mother and nurse of English gentility." Of
the eight baronies of the earldom none survives, but the title of that
of Kinderton was bestowed in 1762 on George Venables-Vernon, son of
Anne, sister of Peter Venables, last baron of Kinderton, from whom the
present Lord Vernon of Kinderton is descended. Other great Domesday
proprietors were William FitzNigel, baron of Halton, ancestor of the
Lacys; Hugh de Mara, baron of Montalt, ancestor of the Ardens; Ranulph,
ancestor of the Mainwarings; and Hamo de Massey. The Davenports, Leighs
and Warburtons trace their descent back to the 12th century, and the
Grosvenors are descended from a nephew of Hugh Lupus.

In the reign of Henry VIII. the distinctive privileges of Cheshire as a
county palatine were considerably abridged. The right of sanctuary
attached to the city of Chester was abolished; justices of the peace
were appointed as in other parts of the kingdom, and in 1542 it was
enacted that in future two knights for the shire and two burgesses for
the city of Chester should be returned to parliament. After the Reform
Act of 1832 the county returned four members from two divisions, and
Macclesfield and Stpckport returned two members each. Birkenhead secured
representation in 1859. From 1868 until the Redistribution Act of 1885
the county returned six members from three divisions.

From earliest times the staple products of Cheshire have been salt and
cheese. The salt-pits of Nantwich, Middlewich and Northwich were in
active operation at the time of Edward the Confessor, and at that date
the mills and fisheries on the Dee also furnished a valuable source of
revenue. Twelfth century writers refer to the excellence of Cheshire
cheese, and at the time of the Civil War three hundred tons at £33 per
ton were ordered in one year for the troops in Scotland. The trades of
tanners, skinners and glove-makers existed at the time of the Conquest,
and the export trade in wool in the 13th and 14th centuries was
considerable. The first bed of rock-salt was discovered in 1670. Weaving
and wool-combing were introduced in 1674.

_Antiquities._--The main interest in the architecture of the county
lies in the direction of domestic buildings rather than ecclesiastical.
Old half-timbered houses are common in almost every part of the county;
many of these add to the picturesqueness of the streets in the older
towns, as in the case of the famous Rows in Chester, while in the
country many ancient manor-houses remain as farm-houses. Among the
finest examples are Bramhall Hall, between Stockport and Macclesfield,
and Moreton Old Hall, near Congleton (see HOUSE, Plate IV., fig. 13).
The first, occupying three sides of a quadrangle (formerly completed by
a fourth side), dates from the 13th and 14th centuries, and contains a
splendid panelled hall and other rooms. Of Moreton Hall, which is
moated, only three sides similarly remain; its date is of the 16th
century. Other buildings of the Elizabethan period are not infrequent,
such as Brereton and Dorfold Halls, while more modern mansions, set in
fine estates, are numerous. Crewe Hall is a modern building on an
ancient site, and Vale Royal near Winsford incorporates fragments of a
Cistercian monastery founded in 1277. A noteworthy instance of the
half-timbered style applied to an ecclesiastical building is found in
the church of Lower Peover near Knutsford, of which only the tower is of
stone. The church dates from the 13th century, and was carefully
restored in 1852. Cheshire has no monastic remains of importance, save
those attached to the cathedral of Chester, nor are its village churches
as a rule of special interest. There is, however, a fine late
Perpendicular church (with earlier portions) at Astbury near Congleton,
and of this style and the Decorated the churches of Bunbury and Malpas
may be noticed as good illustrations. In Chester, besides the cathedral,
there is the massive Norman church of St John; and St Michael's church
and the Rivers chapel at Macclesfield are noteworthy. No more remarkable
religious monuments remain in the county than the two sculptured Saxon
crosses in the market-place at Sandbach. Ruins of two Norman castles
exist in Beeston and Halton.

  AUTHORITIES.--Sir John Doddridge, _History of the Ancient and Modern
  State of the Principality of Wales, Duchy of Cornwall, and Earldom of
  Chester_ (London, 1630; 2nd ed., 1714); D. King, _The Vale-Royall of
  England, or the County Palatine of Cheshire Illustrated_, 4 parts
  (London, 1656); D. and S. Lysons, _Magna Britannia_, vol. ii. pt. ii.
  (London, 1810); J. H. Hanshall, _History of the County Palatine of
  Chester_ (Chester, 1817-1823); J.O. Halliwell, _Palatine Anthology_
  (London, 1850); G. Ormerod, _History of the County Palatine and City
  of Chester_ (London, 1819; new ed., London, 1875-1882); J.P. Earwaker,
  _East Cheshire_ (2 vols., London, 1877); R. Wilbraham, _Glossary_
  (London, 1820; 2nd ed., London, 1826); and _Glossary founded on
  Wilbraham_ by E. Leigh (London, 1877); J. Croston, _Historic Sites of
  Cheshire_ (Manchester, 1883); and _County Families of Cheshire_
  (Manchester, 1887); W.E.A. Axon, _Cheshire Gleanings_ (Manchester,
  1884); Holland, _Glossary of Words used in the County of Cheshire_
  (London, 1884-1886); N.G. Philips, _Views of Old Halls in Cheshire_
  (London, 1893); _Victoria County History, Cheshire_. See also various
  volumes of the Chetham Society and of the Record Society of
  Manchester, as well as the _Proceedings_ of the Cheshire Antiquarian
  Society, and _Cheshire Notes and Queries_.



CHESHUNT, an urban district in the Hertford parliamentary division of
Hertfordshire, England, on the Lea, 14 m. N. of London by the Great
Eastern railway. Pop. (1891) 9620; (1901) 12,292. The church of St Mary
is Perpendicular and has been enlarged in modern times. A college was
founded, for the education of young men to the ministry of the
Connexion, by Selina countess of Huntingdon in 1768 at Trevecca-isaf
near Talgarth, Brecknockshire. In 1792 it was moved to Cheshunt, and
became known as Cheshunt College. In 1904, as it was felt that the
college was unable properly to carry on its work under existing
conditions, it was proposed to amalgamate it with Hackney College, but
the Board of Education refused to sanction any arrangement which would
set aside the requirements of the deed of foundation, namely that the
officers and students of Cheshunt College should subscribe the fifteen
articles appended to the deed, and should take certain other
obligations. In 1905 it was decided by the board to reorganize the
college and remove it to Cambridge.

Nursery and market gardening, largely under glass, brick-making and
saw-mills are the chief industries of Cheshunt. Roman coins and other
remains have been found at this place, and an urn appears built into the
wall of an inn. A Romano-British village or small town is indicated.
There was a Benedictine nunnery here in the 13th century. Of several
interesting mansions in the vicinity one, the Great House, belonged to
Cardinal Wolsey, and a former Pengelly House was the residence of
Richard Cromwell the Protector after his resignation. Theobalds Park was
built in the 18th century, but the original mansion was acquired by
William Cecil, Lord Burghley, in 1561; being taken in 1607 by James I.
from Robert Cecil, first earl of Salisbury, in exchange for Hatfield
House. James died here in 1625, and Charles I. set out from here for
Nottingham in 1642 at the outset of the Civil War. One of the entrances
to Theobalds Park is the old Temple Bar, removed from Fleet Street,
London, in 1878.



CHESIL BANK (A.S. _ceosol_, pebble bank), a remarkable beach of shingle
on the coast of Dorsetshire, England. It is separated from the mainland
for 8 m. by an inlet called the Fleet, famous for its swannery, and
continues in all for 18 m. south-eastward from Abbotsbury, terminating
at the so-called Isle of Portland. The height of the bank at the
Portland end is 35 ft. above spring-tide level, and its breadth 200 yds.
The greater height at this end accords with the general-movement of
shingle along this coast from west to east; and for the same reason the
pebbles of the bank decrease in size from 1 to 3 in. in diameter at
Portland to the size of peas at the western end, where the breadth is
only 170 yds.



CHESNELONG, PIERRE CHARLES (1820-1894), French politician, was born at
Orthez in the department of the Basses-Pyrénées, on the 14th of April
1820. In 1848 he proclaimed himself a Republican; but after the
establishment of the Second Empire he changed his views, and in 1865 was
returned to the chamber as the official candidate for his native place.
He at once became conspicuous, both for his eloquence and for his
uncompromising clericalism, especially in urging the necessity for
maintaining the temporal power of the papacy. In 1869 he was again
returned, and, devoting himself with exceptional ability to financial
questions, was in 1870 appointed to report the budget. During and after
the war, for which he voted, he retired for a while into private life;
but in 1872 he was again elected deputy, this time as a Legitimist, and
took his seat among the extreme Right. He was the soul of the
reactionary opposition that led to the fall of Thiers; and in 1873 it
was he who, with Lucien Brun, carried to the comte de Chambord the
proposals of the chambers. Through some misunderstanding, he reported on
his return that the count had accepted all the terms offered, including
the retention of the tricolour flag; and the count published a formal
denial. Chesnelong now devoted himself to the establishment of Catholic
universities and to the formation of Catholic working-men's clubs. In
1876 he was again returned for Orthez, but was unseated, and then beaten
by the republican candidate. On the 24th of November, however, he was
elected to a seat in the senate, where he continued his vigorous polemic
against the progressive attempts of the republican government to
secularize the educational system of France until his death in 1894.



CHESNEY, CHARLES CORNWALLIS (1826-1876), British soldier and military
writer, the third son of Charles Cornwallis Chesney, captain on the
retired list of the Bengal Artillery, and nephew of General F.R.
Chesney, was born in Co. Down, Ireland, on the 29th of September 1826.
Educated at Blundell's school, Tiverton, and afterwards at the Royal
Military Academy, Woolwich, he obtained his first commission as second
lieutenant of engineers in 1845, passing out of the academy at the head
of his term. His early service was spent in the ordinary course of
regimental duty at home and abroad, and he was stationed in New Zealand
during the Crimean War. Among the various reforms in the British
military system which followed from that war was the impetus given to
military education; and in 1858 Captain Chesney was appointed professor
of military history at Sandhurst. In 1864 he succeeded Colonel
(afterwards Sir Edward) Hamley in the corresponding chair at the Staff
College. The writings of these two brilliant officers had a great
influence not only at home, but on the continent and in America.
Chesney's first published work (1863) was an account of the Civil War
in Virginia, which went through several editions. But the work which
attained the greatest reputation was his _Waterloo Lectures_ (1868),
prepared from the notes of lectures orally delivered at the Staff
College. Up to that time the English literature on the Waterloo
campaign, although voluminous, was made up of personal reminiscences or
of formal records, useful materials for history rather than history
itself; and the French accounts had mainly taken the form of fiction. In
Chesney's lucid and vigorous account of the momentous struggle, while it
illustrates both the strategy and tactics which culminated in the final
catastrophe, the mistakes committed by Napoleon are laid bare, and for
the first time an English Writer is found to point out that the
dispositions of Wellington were far from faultless. And in the _Waterloo
Lectures_ the Prussians are for the first time credited by an English
pen with their proper share in the victory. The work attracted much
attention abroad as well as at home, and French and German translations
were published.

Chesney was for many years a constant contributor to the newspaper press
and to periodic literature, devoting himself for the most part to the
critical treatment of military operations, and professional subjects
generally. Some of his essays on military biography, contributed mainly
to the _Edinburgh Review_, were afterwards published separately (1874).
In 1868 he was appointed a member of the royal commission on military
education, under the presidency first of Earl De Grey and afterwards of
Lord Dufferin, to whose recommendations were due the improved
organization of the military colleges, and the development of military
education in the principal military stations of the British army. In
1871, on the conclusion of the Franco-German War, he was sent on a
special mission to France and Germany, and furnished to the government a
series of valuable reports on the different siege operations which had
been carried out during the war, especially the two sieges of Paris.
These reports were published in a large volume, which was issued
confidentially. Never seeking regimental or staff preferment, Colonel
Chesney never obtained any, but he held at the time of his death a
unique position in the army, altogether apart from and above his actual
place in it. He was consulted by officers of all grades on professional
matters, and few have done more to raise the intellectual standard of
the British officer. Constantly engaged in literary pursuits, he was
nevertheless laborious and exemplary in the discharge of his public
duties, while managing also to devote a large part of his time to
charitable and religious offices. He was abstemious to a fault; and,
overwork of mind and body telling at last on a frail constitution, he
died after a short illness on the 19th of March 1876. He had become
lieutenant-colonel in 1873, and at the time of his death he was
commanding Royal Engineer of the London district. He was buried at
Sandhurst.



CHESNEY, FRANCIS RAWDON (1789-1872), British general and explorer, was
the son of Captain Alexander Chesney, an Irishman of Scottish descent
who, having emigrated to South Carolina in 1772, did brilliant service
under Lord Rawdon (afterwards marquess of Hastings) in the War of
Independence, and subsequently received an appointment as coast officer
at Annalong, Co. Down, Ireland. There F.R. Chesney was born on the 16th
of March 1789. Lord Rawdon gave the boy a cadetship at Woolwich, and he
was gazetted to the Royal Artillery in 1805. But though he rose to be
lieutenant-general and colonel-commandant of the 14th brigade Royal
Artillery (1864), and general in 1868, Chesney's memory lives not for
his military record, but for his connexion with the Suez Canal, and with
the exploration of the Euphrates valley, which started with his being
sent out to Constantinople in the course of his military duties in 1829,
and his making a tour of inspection in Egypt and Syria. His report in
1830 on the feasibility of making the Suez Canal was the original basis
of Lesseps' great undertaking (in 1869 Lesseps greeted him in Paris as
the "father" of the canal); and in 1831 he introduced to the home
government the idea of opening a new overland route to India, by a
daring and adventurous journey (for the Arabs were hostile and he was
ignorant of the language) along the Euphrates valley from Anah to the
Persian Gulf. Returning home, Colonel Chesney (as he then was) busied
himself to get support for the latter project, to which the East India
Company's board was favourable; and in 1835 he was sent out in command
of a small expedition, for which parliament voted £20,000, in order to
test the navigability of the Euphrates. After encountering immense
difficulties, from the opposition of the Egyptian pasha, and from the
need of transporting two steamers (one of which was lost) in sections
from the Mediterranean over the hilly country to the river, they
successfully arrived by water at Bushire in the summer of 1836, and
proved Chesney's view to be a practicable one. In the middle of 1837 he
returned to England, and was given the Royal Geographical Society's gold
medal, having meanwhile been to India to consult the authorities there;
but the preparation of his two volumes on the expedition (published in
1850) was interrupted by his being ordered out in 1843 to command the
artillery at Hong Kong. In 1847 his period of service was completed, and
he went home to Ireland, to a life of retirement; but both in 1856 and
again in 1862 he went out to the East to take a part in further surveys
and negotiations for the Euphrates valley railway scheme, which,
however, the government would not take up, in spite of a favourable
report from the House of Commons committee in 1871. In 1868 he published
a further volume of narrative on his Euphrates expedition. He died on
the 30th of January 1872.

  His _Life_, edited by Stanley Lane Poole, appeared in 1885.



CHESNEY, SIR GEORGE TOMKYNS (1830-1895), English general, brother of
Colonel C.C. Chesney, was born at Tiverton, Devonshire, on the 30th of
April 1830. Educated at Blundell's school, Tiverton, and at Addiscombe,
he entered the Bengal Engineers as second lieutenant in 1848. He was
employed for some years in the public works department and, on the
outbreak of the Indian Mutiny in 1857, joined the Ambala column, was
field engineer at the battle of Badli-ke-serai, brigade-major of
engineers throughout the siege of Delhi, and was severely wounded in the
assault (medal and clasp and a brevet majority). In 1860 he was
appointed head of a new department in connexion with the public works
accounts. His work on _Indian Polity_ (1868), dealing with the
administration of the several departments of the Indian government,
attracted wide attention and remains a permanent text-book. The
originator of the Royal Indian Civil Engineering College at Cooper's
Hill, Staines, he was also its first president (1871-1880). In 1871 he
contributed to _Blackwood's Magazine_, "The Battle of Dorking," a vivid
account of a supposed invasion of England by the Germans after their
victory over France. This was republished in many editions and
translations, and produced a profound impression. He was promoted
lieutenant-colonel, 1869; colonel, 1877; major-general, 1886;
lieutenant-general, 1887; colonel-commandant of Royal Engineers, 1890;
and general, 1892. From 1881 to 1886 he was secretary to the military
department of the government of India, and was made a C.S.I, and a
C.I.E. From 1886 to 1892, as military member of the governor-general's
council, he carried out many much-needed military reforms. He was made a
C.B. at the jubilee of 1887, and a K.C.B. on leaving India in 1892. In
that year he was returned to parliament, in the Conservative interest,
as member for Oxford, and was chairman of the committee of service
members of the House of Commons until his death on the 31st of March
1895. He wrote some novels, _The Dilemma_, _The Private Secretary_, _The
Lesters_, &c., and was a frequent contributor to periodical literature.



CHESS, once known as "checker," a game played with certain "pieces" on a
special "board" described below. It takes its name from the Persian word
_shah_, a king, the name of one of the pieces or men used in the game.
Chess is the most cosmopolitan of all games, invented in the East (see
_History_, below), introduced into the West and now domiciled in every
part of the world. As a mere pastime chess is easily learnt, and a very
moderate amount of study enables a man to become a fair player, but the
higher ranges of chess-skill are only attained by persistent labour. The
real proficient or "master" not merely must know the subtle variations
in which the game abounds, but must be able to apply his knowledge in
the face of the enemy and to call to his aid, as occasion demands, all
that he has of foresight, brilliancy and resource, both in attack and in
defence. Two chess players fighting over the board may fitly be compared
to two famous generals encountering each other on the battlefield, the
strategy and the tactics being not dissimilar in spirit.

_The Board, Pieces and Moves._--The chessboard is divided (see
accompanying diagrams) into sixty-four chequered squares. In diagram 1,
the pieces, or chess-men, are arranged for the beginning of a game,
while diagram 2 shows the denomination of the squares according to the
English and German systems of notation. Under diagram 1 are the names of
the various "pieces"--each side, White or Black, having a King, a Queen,
two Rooks (or Castles), two Knights, and two Bishops. The eight men in
front are called Pawns. At the beginning of the game the queen always
stands upon a square of her own colour. The board is so set that each
player has a white square at the right hand end of the row nearest to
him. The rook, knight and bishop on the right of the king are known as
King's rook, King's knight, and King's bishop; the other three as
Queen's rook, Queen's knight, and Queen's bishop.

                BLACK
  +---+---+---+---+---+---+---+---+
  | r | n | b | q | k | b | n | r |
  +---+---+---+---+---+---+---+---+
  | p | p | p | p | p | p | p | p |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  | P | P | P | P | P | P | P | P |
  +---+---+---+---+---+---+---+---+
  | R | N | B | Q | K | B | N | R |
  +---+---+---+---+---+---+---+---+
    Rk. Kt. Bp. Q.  K.  Bp. Kt. Rk.
                WHITE

  DIAGRAM 1.--Showing the arrangement of the pieces at the commencement
    of a game.

Briefly described, the powers of the various pieces and of the pawns are
as follows.

The king may move in any direction, only one square at a time, except in
castling. Two kings can never be on adjacent squares.

The queen moves in any direction square or diagonal, whether forward or
backward. There is no limit to her range over vacant squares; an
opponent she may take; a piece of her own colour stops her. She is the
most powerful piece on the board, for her action is a union of those of
the rook and bishop. The rooks (from the Indian _rukh_ and Persian
_rokh_, meaning a soldier or warrior) move in straight lines--forward or
backward--but they cannot move, diagonally. Their range is like the
queen's, unlimited, with the same exceptions.

The bishops move diagonally in any direction whether backward or
forward. They have an unlimited range, with the same exceptions.

The knights' moves are of an absolutely different kind. They move from
one corner of any rectangle of three squares by two to the opposite
corner; thus, in diagram 3, the white knight can move to the square
occupied by the black one, and vice versa, or a knight could move from C
to D, or D to C. The move may be made in any direction. It is no
obstacle to the knight's move if squares A and B are occupied. It will
be perceived that the knight always moves to a square of a different
colour.

The king, queen, rooks and bishops may capture any foeman which stands
anywhere within their respective ranges; and the knights can capture the
adverse men which stand upon the squares to which they can leap. The
piece which takes occupies the square of the piece which is taken, the
latter being removed from the board. The king cannot capture any man
which is protected by another man.

The moves and capturing powers of the pawns are as follows:--Each pawn
for his first move may advance either one or two squares straight
forward, but afterwards one square only, and this whether upon starting
he exercised his privilege of moving two squares or not. A pawn can
never move backwards. He can capture only diagonally--one square to his
right or left front. A pawn moves like a rook, captures like a bishop,
but only one square at a time. When a pawn arrives at an eighth square,
viz. at the extreme limit of the board, he may, at the option of his
owner, be exchanged for any other piece, so that a player may, e.g.,
have two or more queens on the board at once.

                         BLACK
      a     b     c     d     e     f     g     h
   +-----+-----+-----+-----+-----+-----+-----+-----+
   | qrsq|qktsq| qbsq| qsq | ksq | kbsq|kktsq| krsq|
  8|     |     |     |     |     |     |     |     |8
   | QR8 | QKt8| QB8 |  Q8 |  K8 | KB8 | KKt8| KR8 |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   | qr2 | qkt2| qb2 |  q2 |  k2 | kb2 | kkt2| kr2 |
  7|     |     |     |     |     |     |     |     |7
   | QR7 | QKt7| QB7 |  Q7 |  K7 | KB7 | KKt7| KR7 |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   | qr3 | qkt3| qb3 |  q3 |  k3 | kb3 | kkt3| kr3 |
  6|     |     |     |     |     |     |     |     |6
   | QR6 | QKt6| QB6 |  Q6 |  K6 | KB6 | KKt6| KR6 |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   | qr4 | qkt4| qb4 |  q4 |  k4 | kb4 | kkt4| kr4 |
  5|     |     |     |     |     |     |     |     |5
   | QR5 | QKt5| QB5 |  Q5 |  K5 | KB5 | KKt5| KR5 |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   | qr5 | qkt5| qb5 |  q5 |  k5 | kb5 | kkt5| kr5 |
  4|     |     |     |     |     |     |     |     |4
   | QR4 | QKt4| QB4 |  Q4 |  K4 | KB4 | KKt4| KR4 |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   | qr6 | qkt6| qb6 |  q6 |  k6 | kb6 | kkt6| kr6 |
  3|     |     |     |     |     |     |     |     |3
   | QR3 | QKt3| QB3 |  Q3 |  K3 | KB3 | KKt3| KR3 |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   | qr7 | qkt7| qb7 |  q7 |  k7 | kb7 | kkt7| kr7 |
  2|     |     |     |     |     |     |     |     |2
   | QR2 | QKt2| QB2 |  Q2 |  K2 | KB2 | KKt2| KR2 |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   | qr8 | qkt8| qb8 |  q8 |  k8 | kb8 | kkt8| kr8 |
  1|     |     |     |     |     |     |     |     |1
   | QRsq|QKtsq| QBsq| Qsq | Ksq | KBsq|KKtsq| KRsq|
   +-----+-----+-----+-----+-----+-----+-----+-----+
      a     b     c     d     e     f     g     h
                         WHITE

  DIAGRAM 2.--Showing English and German Methods of Notation.

"Check and Checkmate." The king can never be captured, but when any
piece or pawn attacks him, he is said to be "in check," and the fact of
his being so attacked should be announced by the adverse player saying
"check," whereupon the king must move from the square he occupies, or be
screened from check by the interposition of one of his own men, or the
attacking piece must be captured. If, however, when the king is in
check, none of these things can be done, it is "checkmate" (Persian,
_shah mat_, the king is dead), known generally as "mate," whereupon the
game terminates, the player whose king has been thus checkmated being
the loser. When the adversary has only his king left, it is very easy to
checkmate him with only a queen and king, or only a rook and king. The
problem is less easy with king and two bishops, and still less easy with
king, knight and bishop, in which case the opposing king has to be
driven into a corner square whose colour corresponds with the bishop's,
mate being given with the bishop. A king and two knights cannot mate. To
mate with king and rook the opposing king must be driven on to one of
the four side files and kept there with the rook on the next file, till
it is held by the other king, when the rook mates.

The pawn gives check in the same way as he captures, viz. diagonally.
One king cannot give check to another, nor may a king be moved into
check.

"Check by discovery" is given when a player, by moving one of his
pieces, checks with another of them. "Double check" means attacking the
king at once with two pieces--one of the pieces in this case giving
check by discovery.

"Perpetual check" occurs when one player, seeing that he cannot win the
game, finds the men so placed that he can give check _ad infinitum_,
while his adversary cannot possibly avoid it. The game is then drawn. A
game is also drawn "if, before touching a man, the player whose turn it
is to play, claims that the game be treated as drawn, and proves that
the existing position existed, in the game and at the commencement of
his turn of play, twice at least before the present turn."

  +---+---+
  | N | D |
  +---+---+
  | A | B |
  +---+---+
  | C | n |
  +---+---+

  Knight's move.

"Stalemate." When a king is not in check, but his owner has no move left
save such as would place the king in check, it is "stalemate," and the
game is drawn.

"Castling." This is a special move permitted to the king once only in
the game. It is performed in combination with either rook, the king
being moved two squares laterally, while the rook towards which he is
moved (which must not have previously moved from its square) is placed
next him on the other side; the king must be touched first. The king
cannot castle after having been once moved, nor when any piece stands
between him and the rook, nor if he is in check, nor when he has to
cross a square commanded by an adverse piece or pawn, nor into check. It
will be perceived that after castling with the king's rook the latter
will occupy the KB square, while the king stands on the KKt square, and
if with the queen's rook, the latter will occupy the queen's square
while the king stands on the QB square.

"Taking _en passant_." This is a privilege possessed by any of the pawns
under the following circumstances:--If a pawn, say of the white colour,
stands upon a fifth square, say upon K5 counting from the white side,
and a black pawn moves from Q2 or KB2 to Q4 or KB4 counting from the
black side, the white pawn can take the black pawn _en passant_. For the
purposes of such capture the latter is dealt with as though he had only
moved to Q3 or KB3, and the white pawn taking him diagonally then
occupies the square the captured pawn would have reached had he moved
but one square. The capture can be made only on the move immediately
succeeding that of the pawn to be captured.

"Drawn Game." This arises from a stalemate (noticed above), or from
either player not having sufficient force wherewith to effect checkmate,
as when there are only two kings left on the board, or king and bishop
against king, or king with one knight, or two knights against king, or
from perpetual check. One of the players can call upon the other to give
checkmate in fifty moves, the result of failure being that the game is
drawn. But, if a pawn is moved, or a piece is captured, the counting
must begin again.

A "minor piece" means either a knight or a bishop. "Winning the
exchange" signifies capturing a rook in exchange for a minor piece. A
"passed pawn" is one that has no adverse pawn either in front or on
either of the adjoining files. A "file" is simply a line of squares
extending vertically from one end of the board to the other. An "open
file" is one on which no piece or pawn of either colour is standing. A
pawn or piece is _en prise_ when one of the enemy's men can capture it.
"Gambit" is a word derived from the Ital. _gambetto_, a tripping up of
the heels; it is a term used to signify an opening in which a pawn or
piece is sacrificed at the opening of a game to obtain an attack. An
"opening," or _début_, is a certain set method of commencing the game.
When a player can only make one legal move, that move is called a
"forced move."

_Value of the Pieces._--The relative worth of the chess-men cannot be
definitely stated on account of the increase or decrease of their powers
according to the position of the game and the pieces, but taking the
pawn as the unit the following will be an estimate near enough for
practical purposes:--pawn 1, bishop 3.25, knight 3.25, rook 5, queen
9.50. Three minor pieces may more often than not be advantageously
exchanged for the queen. The knight is generally stronger than the
bishop in the end game, but two bishops are usually stronger than two
knights, more especially in open positions.

_Laws._--The laws of chess differ, although not very materially, in
different countries. Various steps have been taken, but as yet without
success, to secure the adoption of a universal code. In competitions
among English players the particular laws to be observed are specially
agreed upon,--the regulations most generally adopted being those laid
down at length in Staunton's _Chess Praxis_, or the modification of the
_Praxis_ laws issued in the name of the British Chess Association in
1862.

_First Move and Odds._--To decide who moves first, one player conceals a
white pawn in one hand and a black pawn in the other, his adversary not
seeing in which hand the different pawns are put. The other holds out
his hands with the pawns concealed, and his adversary touches one. If
that contains the white pawn, he takes the white men and moves first. If
he draws the black pawn his adversary has the first move, since white,
by convention, always plays first. Subsequently the first move is taken
alternately. If one player, by way of odds, "gives" his adversary a pawn
or piece, that piece is removed before play begins. If the odds are
"pawn and move," or "pawn and two," a black pawn, namely, the king's
bishop's pawn, is removed and white plays one move, or any two moves in
succession. "Pawn and two" is generally considered to be slightly less
in point of odds than to give a knight or a bishop; to give a knight and
a bishop is to give rather more than a rook; a rook and bishop less than
a queen; two rooks rather more than a queen. The odds of "the marked
pawn" can only be given to a much weaker player. A pawn, generally KB's
pawn, is marked with a cap of paper. If the pawn is captured its owner
loses the game; he can also lose by being checkmated in the usual way,
but he cannot give mate to his adversary with any man except the marked
pawn, which may not be moved to an eighth square and exchanged for a
piece.

_Rules._--If a player touch one of his men he must move it, unless he
says _j'adoube_ (I adjust), or words of a similar meaning, to the effect
that he was only setting it straight on its square. If he cannot legally
move a touched piece, he must move his king, if he can, but may not
castle; if not, there is no penalty. He must say _j'adoube_ before
touching his piece. If a player touch an opponent's piece, he must take
it, if he can: if not, move his king. If he can do neither, no penalty.
A move is completed and cannot be taken back, as soon as a player,
having moved a piece, has taken his hand off it. If a player is called
upon to mate under the fifty-move rule, "fifty moves" means fifty moves
and the forty-nine replies to them. A pawn that reaches an eighth square
_must_ be exchanged for some other piece, the move not being complete
until this is done; a second king cannot be selected.

_Modes of Notation._--The English and German methods of describing the
moves made in a game are different. According to the English method each
player counts from his own side of the board, and the moves are denoted
by the names of the files and the numbers of the squares. Thus when a
player for his first move advances the king's pawn two squares, it is
described as follows:--"1. P-K4." The following moves, with the aid of
diagram 2, will enable the reader to understand the principles of the
British notation. The symbol x is used to express "takes"; a dash--to
express "to."

  White.                               Black.
  1. P-K4                              1. P-K4
  2. KKt-KB3                           2. QKt-QB3
     (i.e. King's Knight to the           (i.e. Queen's Knight to the
     third square of the King's           third square of the Queen's
     Bishop's file)                       Bishop's file)
  3. KB-QB4                            3. KB-QB4
     (King's Bishop to the fourth
     square of the Queen's
     Bishop's file)
  4. P-QB3                            4. KKt-KB3
  5. P-Q4                             5. P takes P (or PxP)
                                          (King's pawn takes White's
                                          Queen's pawn)
  6. P takes P (or PxP)                6. KB-QKt5 (ch., i.e. check)
     (Queen's Bishop's pawn
     takes pawn: no other pawn
     has a pawn _en prise_)

It is now usual to express the notation as concisely as possible; thus,
the third moves of White and Black would be given as 3. B-B4, because it
is clear that only the fourth square of the queen's bishop's file is
intended.

The French names for the pieces are, King, _Roi_; Queen, _Dame_; Rook,
_Tour_; Knight, _Cavalier_; Pawn, _Pion_; for Bishop the French
substitute _Fou_, a jester. Chess is _Les Échecs_.

The German notation employs the alphabetical characters a, b, c, d, e,
f, g and h, proceeding from left to right, and the numerals 1, 2, 3, 4,
5, 6, 7 and 8, running upwards, these being always calculated from the
white side of the board (see diagram 2). Thus the White Queen's Rook's
square is a1, the White Queen's square is d1; the Black Queen's square,
d8; the White King's square, e1; the Black King's square, e8, and so
with the other pieces and squares. The German names of the pieces are as
follows:--King, _König_; Queen, _Dame_; Rook, _Turm_; Bishop, _Läufer_;
Knight, _Springer_; Pawn, _Bauer_; Chess, _Schach_.

The initials only of the pieces are given, the pawns (_Bauern)_ being
understood. The Germans use the following signs in their notation,
viz.:--for "check" ([dagger]); "checkmate" ([double dagger]); "takes"
(:); "castles on king's side" (0-0); "castles on queen's side" (0-0-0);
for "best move" a note of admiration (!); for "weak move" a note of
interrogation (?). The opening moves just given in the English will now
be given in the German notation:--

  White.                     Black.
  1. e2-e4                   1. e7-e5
  2. S g1-f3                 2. S b8-c6
  3. L f1-c4                 3. L f8-c5
  4. c2-c3                   4. S g8-f6!
  5. d2-d4                   5. e5-d4:
  6. c3-d4:                  6. L cs-b4[dagger]

In both notations the moves are often given in a tabular form, thus:--

    P-K4     e2-e4
 1. ----  1. -----, the moves above the line being White's
    P-K4     e7-e5
and below the line Black's.

_Illustrative Games._--The text-books should be consulted by students
who wish to improve their game. The following are some of the leading
openings:--


  GIUOCO PIANO.

      White.                    Black.
   1. P-K4                   1. P-K4
   2. KKt-B3                 2. QKt-B3
   3. B-B4                   3. B-B4
   4. P-B3                   4. Kt-KB3
   5. P-Q4                   5. PxP
   6. PxP                    6. B-Kt5 (ch)
   7. B-Q2                   7. BxB (ch)
   8. QKtxB                  8. P-Q4
   9. PxP                    9. KKtxP
  10. Q-Kt3                 10. QKt-K2
  11. Castles (K's side)    11. Castles

  Even game.


  RUY LOPEZ.

      White.                    Black.
   1. P-K4                   1. P-K4
   2. KKt-B3                 2. QKt-B3
   3. B-Kt5                  3. P-QR3
   4. B-R4                   4. Kt-B3
   5. P-Q4                   5. PxP
   6. P-K5                   6. Kt-K5
   7. Castles                7. B-K2
   8. R-K sq                 8. Kt-B4
   9. BxKt                   9. QPxB
  10. KtxP                  10. Castles
  11. Kt-QB3                11. P-KB3

  Even game.


  SCOTCH GAMBIT.

      White.                    Black.
   1. P-K4                   1. P-K4
   2. KKt-B3                 2. QKt-B3
   3. P-Q4                   3. PxP
   4. B-QB4                  4. B-B4
   5. P-B3                   5. Kt-B3
   6. PxP

  The position here arrived at is the same as in the Giuoco Piano
  opening above.


  EVANS GAMBIT.

      White.                    Black.
   1. P-K4                   1. P-K4
   2. KKt-B3                 2. QKt-B3
   3. B-B4                   3. B-B4
   4. P-QKt4                 4. BxKtP
   5. P-B3                   5. B-B4
   6. P-Q4                   6. PxP
   7. Castles                7. P-Q3
   8. PxP                    8. B-Kt3

White has for its ninth move three approved continuations, viz. B-Kt2,
P-Q5, and Kt-B3. To take one of them:--


   9. P-Q5                   9. Kt-R4
  10. B-Kt2                 10. Kt-K2
  11. B-Q3                  11. Castles
  12. Kt-B3                 12. Kt-Kt3
  13. Kt-K2                 13. P-QB4
  14. Q-Q2                  14. P-B3
  15. K-R sq                15. B-B2
  16. QR-B sq               16. R-Kt sq

  This game may be considered about even.


  KING'S KNIGHT'S GAMBIT (PROPER).

      White.                    Black.
   1. P-K4                   1. P-K4
   2. P-KB4                  2. PxP
   3. KKt-B3                 3. P-KKt4
   4. B-B4                   4. B-Kt2
   5. Castles                5. P-Q3
   6. P-Q4                   6. P-KR3
   7. P-B3                   7. Kt-K2

  Black has the advantage.


  ALLGAIER-KIESERITZKI GAMBIT.

      White.                    Black.
   1. P-K4                   1. P-K4
   2. P-KB4                  2. PxP
   3. Kt-KB3                 3. P-KKt4
   4. P-KR4                  4. P-Kt5
   5. Kt-K5                  5. KKt-B3
   6. B-B4                   6. P-Q4
   7. PxP                    7. B-Kt2
   8. P-Q4                   8. Castles
   9. BxP                    9. KtxP
  10. BxKt                  10. QxB
  11. Castles               11. P-QB4

  Black has the better game.


  KING'S BISHOP'S GAMBIT.

      White.                    Black.
   1. P-K4                   1. P-K4
   2. P-KB4                  2. PxP
   3. B-B4                   3. P-Q4
   4. BxP                    4. Q-R5 (ch)
   5. K-B sq                 5. P-KKt4
   6. KKt-B3                 6. Q-R4
   7. P-Q4                   7. B-Kt2
   8. P-KR4                  8. P-KR3
   9. Kt-B3                  9. Kt-K2
  10. K-Kt sq               10. P-Kt5
  11. Kt-K5                 11. BxKt
  12. PxB                   12. QxKP
  13. Q-B sq                13. P-B6
  14. P-P                   14. Q-Kt6 (ch)
  15. Q-Kt2

  Drawn game.


  SALVIO GAMBIT.

      White.                    Black.
   1. P-K4                   1. P-K4
   2. P-KB4                  2. PxP
   3. KKt-B3                 3. P-KKt4
   4. B-B4                   4. P-Kt5
   5. Kt-K5                  5. Q-R5 (ch)
   6. K-B sq                 6. Kt-KR3
   7. P-Q4                   7. P-B6
   8. Kt-QB3                 8. P-Q3
   9. Kt-Q3                  9. PxP (ch)
  10. KxP                   10. B-Kt2
  11. Kt-KB4                11. Kt-B3
  12. B-K3                  12. Castles
  13. QKt-Q5                13. Q-Q sq
  14. P-B3

  White has a slight advantage.


  MUZIO GAMBIT.

     P-K4     P-KB4     KKt-B3      B-B4
  1. ----  2. -----  3. ------   4. ----
     P-K4     PxP       P-KKt4      P-Kt5

      White.                    Black.
   5. Castles                5. PxKt
   6. QxP                    6. Q-B3
   7. P-K5                   7. QxP
   8. P-Q3                   8. B-R3
   9. B-Q2                   9. Kt-K2
  10. Kt-B3                 10. QKt-B3
  11. QR-K sq               11. Q-KB4
  12. R-K4                  12. Castles
  13. QBxP                  13. B-Kt2
  14. Q-K2                  14. P-Q4
  15. BxBP                  15. Q-Kt4
  16. P-KR4                 16. Q-Kt3
  17. KtxP                  17. KtxKt
  18. BxKt                  18. B-B4
  19. QR-KB4                19. B-K3
  20. BxB                   20. PxB
  21. R-K4                  21. RxR (ch)
  22. KxR                   22. R-B sq (ch)
  23. K-Kt sq               23. Kt-Q5

  And Black has the better game.


  QUEEN'S GAMBIT.

      White.                    Black.
   1. P-Q4                   1. P-Q4
   2. P-QB4                  2. PxP
   3. P-K3                   3. P-K4
   4. BxP                    4. PxP
   5. PxP                    5. B-Q3
   6. Kt-KB3                 6. Kt-KB3
   7. Castles                7. Castles
   8. P-KR3                  8. P-KR3
   9. Kt-QB3                 9. P-QB3

The game is about equal, though White has a somewhat freer position.


The following is a selection of noteworthy games played by great
masters:--


  KING'S BISHOP'S GAMBIT.

      White.                    Black.
    Anderssen.               Kieseritzki.
   1. P-K4                   1. P-K4
   2. P-KB4                  2. PxP
   3. B-B4                   3. Q-R5 (ch)
   4. K-B sq                 4. P-QKt4
   5. BxKtP                  5. Kt-KB3
   6. Kt-KB3                 6. Q-R3
   7. P-Q3                   7. Kt-R4
   8. Kt-R4                  8. Q-Kt4
   9. Kt-B5                  9. P-QB3
  10. P-KKt4                10. Kt-B3
  11. R-Kt sq               11. PxB
  12. P-KR4                 12. Q-Kt3
  13. P-R5                  13. Q-Kt4
  14. Q-B3                  14. Kt-Kt sq
  15. BxP                   15. Q-B3
  16. Kt-B3                 16. B-B4
  17. Kt-Q5                 17. QxKtP
  18. B-Q6                  18. QxR (ch)
  19. K-K2                  19. BxR
  20. P-K5                  20. Kt-QR3

  White mates in three moves.


  PHILIDOR'S DEFENCE.

      White.                    Black.
     Barnes.                   Morphy.
   1. P-K4                   1. P-K4
   2. Kt-KB3                 2. P-Q3
   3. P-Q4                   3. P-KB4
   4. PxKP                   4. BPxP
   5. Kt-Kt5                 5. P-Q4
   6. P-K6                   6. B-QB4
   7. Kt-B7                  7. Q-B3
   8. B-K3                   8. P-Q5
   9. B-KKt5                 9. Q-B4
  10. KtxR                  10. QxB
  11. B-B4                  11. Kt-QB3
  12. Kt-B7                 12. QxP
  13. R-B sq                13. Kt-B3
  14. P-KB3                 14. Kt-QKt5
  15. Kt-QR3                15. BxP
  16. BxB                   16. Kt-Q6 (ch)
  17. QxKt                  17. PxQ
  18. Castles               18. BxKt
  19. B-Kt3                 19. P-Q7 (ch)
  20. K-Kt sq               20. B-B4
  21. Kt-K5                 21. K-B sq
  22. Kt-Q3                 22. R-K sq
  23. KtxB                  23. QxR

  And White resigns.


  BISHOP'S GAMBIT.

      White.      Black.                 White.      Black.
    Charousek.   Tchigorin.            Charousek.   Tchigorin.
   1. P-K4        P-K4        |      13. QxP (ch)    K-K2
   2. P-KB4       PxP         |      14. KtxP        KtxKt
   3. B-B4        Kt-QB3      |      15. BxKt        P-R3
   4. P-Q4        Kt-B3       |      16. Kt-B3       B-B5
   5. P-K5        P-Q4        |      17. P-K6        R-B sq
   6. B-Kt3       B-Kt5       |      18. B-B7        PxP
   7. Q-Q3        Kt-KR4      |      19. BxQ (ch)    RxB
   8. Kt-KR3      Kt-Kt5      |      20. Q-Kt7 (ch)  R-Q2
   9. Q-QB3       Kt-R3       |      21. R-B7 (ch)   KxR
  10. Castles     B-K7        |      22. QxR (ch)    B-K2
  11. B-R4 (ch)   P-B3        |      23. R-K sq      R-K sq
  12. BxP (ch)    PxB         |      24. P-QKt3      Resigns.

This pretty game was played in the tie match for first prize at the
Budapest tournament, 1896.


  QUEEN'S GAMBIT DECLINED.

      White.      Black.                 White.      Black.
  W. Steinitz.  Dr E. Lasker.        W. Steinitz.  Dr E. Lasker.
   1. P-Q4        P-Q4        |      21. Kt-B3       Kt-Q5
   2. P-QB4       P-K3        |      22. QxP         KtxB (ch)
   3. Kt-QB3      Kt-KB3      |      23. PxKt        R-Kt sq
   4. B-B4        B-K2        |      24. QxP         R-Kt3
   5. P-K3        Castles     |      25. Q-B4        RxP
   6. R-B sq      P-B4        |      26. P-KR4       B-R2
   7. QPxP        BxP         |      27. B-K4        Q-Q3
   8. PxP         PxP         |      28. P-B4        Q-Q2
   9. Kt-B3       Kt-B3       |      29. B-Kt2       Q-Kt5
  10. B-Q3        P-Q5        |      30. Q-Q3        Kt-B4
  11. PxP         KtxP        |      31. Kt-K4       B-K6
  12. Castles     B-KKt5      |      32. R-B3        RxB
  13. Kt-QKt5     BxKt        |      33. KxR         KtxP (ch)
  14. P-B         Kt-K3       |      34. K-R2        KtxR (ch)
  15. B-K5        Kt-R4       |      35. K-Kt2       Kt-R5 (ch)
  16. K-R sq      Q-Kt4       |      36. K-R2        Kt-B4
  17. B-Kt3       QR-Q sq     |      37. R-QKt sq    P-R4
  18. Q-B2        Q-R3        |      38. R-Kt5       R-R sq
  19. QR-Q sq     R-B sq      |      39. P-R3        RxP
  20. Q-Kt3       P-R3        |           Resigns.

This game was played in the St Petersburg tournament, 1895, a fine
specimen of Lasker's style. The final attack, beginning with 21. with
Kt-Q5, furnishes a gem of an ending.


  RICE GAMBIT.

      White.      Black.                 White.      Black.
     Professor   Major                  Professor   Major
       Rice.     Hanham.                  Rice.     Hanham.
   1. P-K4        P-K4        |      15. Q-R3        Kt-B7
   2. P-KB4       PxP         |      16. RxB (ch)    B-K3
   3. Kt-KB3      P-KKt4      |      17. K-B sq      Q-R8 (ch)
   4. P-KR4       P-Kt5       |      18. Kt-Kt sq    Kt-R6
   5. Kt-K5       Kt-KB3      |      19. PxKt        P-B6
   6. B-B4        P-Q4        |      20. B-Kt5       Q-Kt7 (ch)
   7. PxP         B-Q3        |      21. K-K sq      P-B7 (ch)
   8. Castles     BxKt        |      22. K-Q2        P-B8=Kt (ch)
   9. R-K sq      Q-K2        |      23. K-Q3        K-Q2
  10. P-B3        P-Kt6       |      24. PxB (ch)    K-B2
  11. P-Q4        Kt-Kt5      |      25. Q-K7 (ch)   K-Kt3
  12. Kt-Q2       QxP         |      26. Q-Q8 (ch)   RxQ
  13. Kt-B3       Q-R3        |      27. BxQ and mates
  14. Q-R4 (ch)   P-B3        |

The Rice Gambit (so called after its inventor, Prof. Isaac L. Rice of
New York), whether right or not, is only possible if Black plays 7.
B-Q3. Paulsen's 7. B-Kt2 is better, and avoids unnecessary
complications. 8. P-Q4 is the usual move. Leaving the knight _en prise_,
followed by 9. R-K sq, constitutes the Rice Gambit. The interesting
points in the game are that White subjects himself to a most violent
attack with impunity, for in the end Black could not save the game by
22. P-B8 claiming a second queen with a discovered check, nor by
claiming a knight with double check, as it is equally harmless to White.


  GIUOCO PIANO.

       White.     Black.                 White.      Black.
    Steinitz.   Bardeleben.            Steinitz.   Bardeleben.
   1. P-K4        P-K4        |      14. R-K sq      P-KB3
   2. Kt-KB3      Kt-QB3      |      15. Q-K2        Q-Q2
   3. B-B4        B-B4        |      16. QR-B sq     P-B3
   4. P-B3        Kt-B3       |      17. P-Q5        PxP
   5. P-Q4        PxP         |      18. Kt-Q4       K-B2
   6. PxP         B-Kt5 (ch)  |      19. Kt-K6       KR-QB sq
   7. Kt-B3       P-Q4        |      20. Q-Kt4       P-KKt3
   8. PxP         KKtxP       |      21. Kt-Kt5 (ch) K-K sq
   9. Castles     B-K3        |      22. RxKt (ch)   K-B sq
  10. B-KKt5      B-K2        |      23. R-B7 (ch)   K-Kt sq
  11. BxKt        QBxB        |      24. R-Kt7 (ch)  K-R sq
  12. KtxB        QxKt        |      25. RxP (ch)    Resigns.
  13. BxB         KtxB        |

As a matter of fact, Bardeleben left the board here, and lost the game
by letting his clock run out the time-limit; but Steinitz, who remained
at the board, demonstrated afterwards the following variation leading to
a forced win:--

       White.     Black.                 White.      Black.
     Steinitz.  Bardeleben.            Steinitz.   Bardeleben.
  25. ......      K-Kt sq     |      31. Q-Kt8 (ch)  K-K2
  26. R-Kt7 (ch)  K-R sq      |      32. Q-B7 (ch)   K-Q sq
  27. Q-R4 (ch)   KxR         |      33. Q-B8 (ch)   Q-K sq
  28. Q-R7 (ch)   K-B sq      |      34. Kt-B7 (ch)  K-Q2
  29. Q-R8 (ch)   K-K2        |      35. Q-Q6 mate.
  30. Q-Kt7 (ch)  K-K sq      |

This game was awarded the prize for "brilliancy" at the Hastings
tournament, 1895.


  RUY LOPEZ.

      White.      Black.                 White.      Black.
     Halprin.  Pillsbury.               Halprin.  Pillsbury.
   1. P-K4        P-K4        |      14. P-Kt6       BPxP
   2. Kt-KB3      Kt-QB3      |      15. Kt-Q5       PxKt
   3. B-Kt5       Kt-B3       |      16. KR-K sq(ch) K-B sq
   4. Castles     KtxP        |      17. R-R3        Kt-K4
   5. P-Q4        Kt-Q3       |      18. RxKt        PxR
   6. PxP         KtxB        |      19. R-B3 (ch)   K-Kt sq
   7. P-QR4       P-Q3        |      20. B-R6        Q-K2
   8. P-K6        PxP         |      21. BxP         KxB
   9. PxKt        Kt-K2       |      22. R-Kt3 (ch)  K-B sq
  10. Kt-B3       Kt-Kt3      |      23. R-B3 (ch)   K-Kt2
  11. Kt-Kt5      B-K2        |      24. R-Kt3 (ch)  K-B sq
  12. Q-R5        BxKt        |      25. R-B3 (ch)   K-Kt sq
  13. BxB         Q-Q2        |                Draw.

This brilliant game, played at the Munich tournament, 1900, would be
unique had the combinations occurred spontaneously in the game. As a
matter of fact, however, the whole variation had been elaborated by
Maroczy and Halprin previously, on the chance of Pillsbury adopting the
defence in the text. The real merit belongs to Pillsbury, who had to
find the correct defence to an attack which Halprin had committed to
memory and simply had to be careful to make the moves in regular order.


  SICILIAN DEFENCE.

      White.      Black.                 White.      Black.
    Pillsbury.   Mieses.               Pillsbury.   Mieses.
   1. P-K4        P-QB4       |      16. PxP         Kt-Q5
   2. Kt-KB3      P-K3        |      17. BxR         KxB
   3. P-Q4        PxP         |      18. R-R2        B-K3
   4. KtxP        Kt-KB3      |      19. R-Q2        R-K sq
   5. Kt-QB3      Kt-B3       |      20. Castles     B-Kt6
   6. KKt-Kt5     B-Kt5       |      21. Q-Kt sq     B-Q4
   7. P-QR3       BxKt (ch)   |      22. B-Q sq      BxP
   8. KtxB        P-Q4        |      23. KxB         Q-Kt4 (ch)
   9. PxP         PxP         |      24. K-R sq      QxR
  10. B-KKt5      Castles     |      25. B-Kt4       Q-B5
  11. B-K2        P-Q5        |      26. R-Kt sq     P-B4
  12. Kt-K4       Q-R4 (ch)   |      27. B-R5        Kt-B6
  13. P-Kt4       Q-K4        |      28. BxKt        QxB (ch)
  14. KtxKt (ch)  PxKt        |      29. R-Kt2       R-K7
  15. B-R6        P-Q6        |      30. Q-QB sq     QxQP
                      Drawn eventually.

This brilliant game occurred at the Paris tournament, 1900.


  EVANS GAMBIT.

      White.      Black.
    Anderssen.   Dufresne.
   1. P-K4        P-K4        |      13. Q-R4        B-Kt3
   2. Kt-KB3      Kt-QB3      |      14. QKt-Q2      B-Kt2
   3. B-B4        B-B4        |      15. Kt-K4       Q-B4
   4. P-QKt4      BxP         |      16. BxP         Q-R4
   5. P-B3        B-R4        |      17. Kt-B6 (ch)  PxKt
   6. P-Q4        PxP         |      18. PxP         R-Kt sq
   7. Castles     P-Q6        |      19. QR-Q sq     QxKt
   8. Q-Kt3       Q-B3        |      20. RxKt (ch)   KtxR
   9. P-K5        Q-Kt3       |      21. QxP (ch)    KxQ
  10. R-K sq      KKt-K2      |      22. B-B5 (ch)   K-K sq
  11. B-R3        P-Kt4       |      23. B-Q7 (ch)   K moves
  12. QxP         R-QKt sq    |      24. BxKt mate.

This game is most remarkable and brilliant. The _coup de repos_ of 19.
QR - Q sq is the key - move to the brilliant final combination, the
depth and subtlety of which have never been equalled, except perhaps in
the following game between Zukertort and Blackburne:--


  ENGLISH OPENING.

      White.      Black.                 White.        Black.
    Zukertort.  Blackburne.            Zukertort.    Blackburne.
   1. P-QB4       P-K3        |      18. P-K4          QR-QB sq
   2. P-K3        Kt-KB3      |      19. P-K5          Kt-K sq
   3. Kt-KB3      P-QKt3      |      20. P-B4          P-Kt3
   4. B-K2        B-Kt2       |      21. R-K3          P-B4
   5. Castles     P-Q4        |      22. PxP e.p.      KtxP
   6. P-Q4        B-Q3        |      23. P-B5          Kt-K5
   7. Kt-B3       Castles     |      24. BxKt          PxB
   8. P-QKt3      QKt-Q2      |      25. PxKtP         R-B7
   9. B-Kt2       Q-K2        |      26. PxP (ch)      K-R sq
  10. Kt-QKt5     Kt-K5       |      27. P-Q5 dis.(ch) P-K4
  11. KtxB        PxKt        |      28. Q-Kt4         QR-B4
  12. Kt-Q2       QKt-B3      |      29. R-B8 (ch)     KxP
  13. P-B3        KtxKt       |      30. QxP (ch)      K-Kt2
  14. QxKt        PxP         |      31. BxP (ch)      KxR
  15. BxP         P-Q4        |      32. B-Kt7 (ch)    K-Kt sq
  16. B-Q3        KR-B sq     |      33. QxQ           Resigns.
  17. QR-K sq     R-B2        |

This game, played in the London tournament, 1883, is one of the most
remarkable productions of modern times, neither surpassed nor indeed
equalled hitherto.

_End Games._--A game of chess consists of three branches--the opening,
the middle and the end game. The _openings_ have been analysed and are
to be acquired by the study of the books on the subject. The _middle
game_ can only be acquired practically. The combinations being
inexhaustible in their variety, individual ingenuity has its full scope.
Those endowed with a fertile imagination will evolve plans and
combinations leading to favourable issues. The less endowed player,
however, is not left quite defenceless; he has necessarily to adopt a
different system, namely, to try to find a weak point in the arrangement
of his opponent's forces and concentrate his attack on that weak spot.
As a matter of fact, in a contest between players of equal strength,
finding the weak point in the opponent's armour is the only possible
plan, and this may be said to be the fundamental principle of the modern
school. In the good old days the battles were mostly fought in the
neighbourhood of the king, each side striving for a checkmate. Nowadays
the battle may be fought anywhere. It is quite immaterial where the
advantage is gained be it ever so slight. Correct continuation will
necessarily increase it, and the opponent may be compelled to surrender
in the end game without being checkmated, or a position may be reached
when the enemies, in consequence of the continual fight, are so reduced
that the kings themselves have to take the field--the end game. The _end
game_, therefore, requires a special study. It has its special laws and
the value of the pieces undergoes a considerable change. The kings leave
their passive rôle and become attacking forces. The pawns increase in
value, whilst that of the pieces may diminish in certain cases. Two
knights, for instance, without pawns, become valueless, as no checkmate
can be effected with them. In the majority of cases the players must be
guided by general principles, as the standard examples do not meet
all-cases.

The handbooks as a rule give a sprinkling of elementary endings, such as
to checkmate with queen, rook, bishop and knight, two bishops, and pawn
endings pure and simple, as well as pawns in connexion with pieces in
various forms. Towards the end of the 19th century a valuable work on
end games was published in England by the late B. Horwitz; thus for the
first time a theoretical classification of the art was given. This was
followed by a more comprehensive work by Professor J. Berger of Gratz,
which was translated a few years later by the late Mr Freeborough.

A few specimens of the less accessible positions are given below:--


_Position from a Game played by the late J.G. Campbell in 1863._

                BLACK.
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |BP |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |WP |   |BP |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |BK |   |BP |   |   |WB |   |
  +---+---+---+---+---+---+---+---+
  |WP |   |   |WP |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |BP |BP |
  +---+---+---+---+---+---+---+---+
  |   |WP |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |BK |   |   |
  +---+---+---+---+---+---+---+---+
                WHITE.

Obviously White has to lose the game, not being able to prevent the
pawns from queening. By a remarkably ingenious device White averts the
loss of the game by stalemating himself as follows:--

1. B-Q2, P-Kt7; 2. B-R5, P-Kt8 = Q; 3. P-Kt4 stalemate.


_Position by Sarratt, 1808_.

                BLACK.
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |BP |BP |BP |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |BK |
  +---+---+---+---+---+---+---+---+
  |WP |WP |WP |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |WK |   |
  +---+---+---+---+---+---+---+---+
                WHITE.

White wins as follows:--

1. P-Kt6, RPxP; 2. P-B6, P(Kt2)xP; 3. P-R6 and wins by queening the
pawn. If 1. ... BPXP then 2. P-R6, KtPXP; 3-P-B6 and queens the pawn.

_Problems._--A chess problem[1] has been described as "merely a
position supposed to have occurred in a game of chess, being none other
than the critical point where your antagonist announces checkmate in a
given number of moves, no matter what defence you play," but the above
description conveys no idea of the degree to which problem-composing has
become a specialized study. Owing its inception, doubtless, to the
practice of recording critical phases from actual play, the art of
problem composition has so grown in favour as to earn the title of the
"poetry" of the game.


_Position by B. Horwitz._

                BLACK.
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |WK |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |BP |   |WQ |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |BK |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
                WHITE.

As a rule the game should be drawn. Supposing by a series of checks
White were to compel Black to abandon the pawn, he would move K - R8; Q
x P and Black is stale-mate. Therefore the ingenious way to win is:--

1. K-B4, P-B8 = Q ch; K-Kt3 and wins. Or 1. ... K-R8 (threatening P-B8 =
Kt); then 2. Q-Q2 preliminary to K-Kt3 now wins.


_Position by B. Horwitz._

                BLACK.
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |WK |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |WKn|   |BP |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |WKn|   |BK |
  +---+---+---+---+---+---+---+---+
                WHITE.

Without Black's pawn White could only draw. The pawn being on the board,
White wins as follows:--

1. Kt-B4, K-Kt sq; 2. Kt (B4)-K3, K-R sq; 3. K-Kt4, K-Kt sq; 4. K-R3,
K-R sq; 5. Kt-B4, K-Kt sq; 6. Kt (B4)-Q2, K-R sq; 7. Kt-Kt3 ch, K-Kt sq;
8. Kt-B3 mate.


_Position by B. Horwitz._

                BLACK.
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |BK |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |WK |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |BB |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |WKn|   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |WB |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
                WHITE.

White wins with two pieces against one--a rare occurrence.

1. Kt-K6, B-R3; 2. B-Q4 ch, K-R2; 3. B-B3, B moves anywhere not _en
prise_; 4. B-Kt7 and Kt mates.


_Position by O. Schubert._

                BLACK.
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |BP |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |BP |WB |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |BK |WP |   |WP |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |WK |   |   |BKn|
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
                WHITE.

White wins as follows:--

1. P-Kt5, Kt-Kt5; 2. K-B3, Kt-K6; 3. B-K6, Kt-B8; 4. BxP, Kt-Q7 ch; 5.
K-Kt4, KtxP; 6. P-Kt6, Kt-B3, ch; 7. K-Kt5, P-K5; 8. KxKt, P-K6; 9.
B-B4, KxB; 10. P-Kt7, P-K7; 11. P-Kt8 = Q ch, and wins by the simple
process of a series of checks so timed that the king may approach
systematically. The fine points in this instructive ending are the two
bishop's moves, 3. B - K6, and 9. B - B4, the latter move enabling White
to queen the pawn with a check.


_Position by F. Amelung._

                BLACK.
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |BP |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |WP |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |BP |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |BK |   |   |   |WK |   |WR |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |BB |   |   |BR |
  +---+---+---+---+---+---+---+---+
                WHITE.

White with the inferior position saves the game as follows:--

1. P-R6, PxP; 2. K-B3 dis. ch, K moves; 3. R-R2, or Kt2 ch, KxR; 4.
K-Kt2 and draw, as Black has to give up the rook, and the RP cannot be
queened, the Black bishop having no power on the White diagonal.
Extremely subtle.


_Position by B. Horwitz._

                BLACK.
  +---+---+---+---+---+---+---+---+
  |WQ |   |   |   |   |   |   |BR |
  +---+---+---+---+---+---+---+---+
  |   |WB |   |   |   |   |BQ |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |WK |   |BK |BP |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |WP |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |WP |BP |WP |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |WP |   |
  +---+---+---+---+---+---+---+---+
  |   |BB |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
                WHITE.

The main idea being to checkmate with the bishop, this is accomplished
thus:--1. B-K4 ch, K-R4; 2. QxR, QxQ; 3. K-B7, Q-B sq ch; 4. KxQ, BXP;
5. K-B7, BxP; 6. B-Kt6 mate.


_Position by A. Troitzky._

                BLACK.
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |BR |BK |BB |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |BKn|BP |   |WP |
  +---+---+---+---+---+---+---+---+
  |   |   |   |WP |   |WKn|   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |WP |   |WK |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |BR |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
                WHITE.

White wins as follows:--

1. P-R8=Q, R-R7 ch; 2. K-Kt5, RxQ; 3. Kt-Q7 ch, K-Kt2; 4. P-B6 ch, K-R2;
5. QPxKt, R-R sq; 6. Kt-B8 ch, RxKt; 7. PxR=Kt mate.


_Position by Hoffer._

                BLACK.
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |BR |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |BQ |   |   |   |BP |BK |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |WQ |BKn|   |BP |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |WR |   |   |
  +---+---+---+---+---+---+---+---+
  |WP |WP |   |   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |WKn|   |BKn|   |   |   |   |   |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |   |WP |WP |
  +---+---+---+---+---+---+---+---+
  |   |   |   |   |   |WR |   |WK |
  +---+---+---+---+---+---+---+---+
                WHITE.

A position from actual play. White plays 1. R-B5 threatening to win a
piece. Black replies with the powerful Kt-Kt5, threatening two mates,
and finally White (Mr Hoffer) finds an ingenious sacrifice of the
Queen--the saving clause.

The following are the moves:--

1. R-B5, Kt-Kt5; 2. Q-Kt8 ch, K-Kt3; 3. Q-K6 ch, K-R2; 4. Q-Kt8 ch, and
drawn by perpetual check, as Black cannot capture the Queen with K or R
without losing the game.

A good chess problem exemplifies chess strategy idealized and
concentrated. In examples of actual play there will necessarily remain
on the board pieces immaterial to the issue (checkmate), whereas in
problems the composer employs only _indispensable_ force so as to focus
attention on the idea, avoiding all material which would tend to
"obscure the issue." Hence the first object in a problem is to extract
the maximum of _finesse_ with a sparing use of the pieces, but "economy
of force" must be combined with "purity of the mate." A very common
mistake, until comparatively recent years, was that of appraising the
"economy" of a position according to the slenderness of the force used,
but economy is not a question of absolute values. The true criterion is
the ratio of the force employed to the skill demanded. The earliest
composers strove to give their productions every appearance of real
play, and indeed their compositions partook of the nature of ingenious
end-games, in which it was usual to give Black a predominance of force,
and to leave the White king in apparent jeopardy. From this predicament
he was extricated by a series of checking moves, usually involving a
number of brilliant sacrifices. The number of moves was rarely less than
five. In the course of time the solutions were reduced to shorter limits
and the beauty of quiet (non-checking) moves began to make itself felt.
The early transition school, as it has been called, was the first to
recognize the importance of economy, i.e. the representation of the main
strategic point without any extraneous force. The mode of illustrating
single-theme problems, often of depth and beauty, was being constantly
improved, and the problems of C. Bayer, R. Willmers, S. Loyd, J.G.
Campbell, F. Healey, "J.B." of Bridport, and W. Grimshaw are, of their
kind, unsurpassed. In the year 1845 the "Indian" problem attracted much
notice, and in 1861 appeared Healey's famous "Bristol" problem. To this
period must be ascribed the discovery of most of those clever ideas
which have been turned to such good account by the later school. In an
article written in 1899 F.M. Teed mentions the fact that his
_incomplete_ collection of "Indians" totalled over three hundred.

In 1870 or thereabouts, the later transition period, a more general
tendency was manifest to illustrate two or more finished ideas in a
single problem with strict regard to purity and economy, the theory of
the art received greater attention than before and the essays of C.
Schwede, Kohtz and Kockelkorn, Lehner and Gelbfuss, helped to codify
hitherto unwritten rules of taste. The last quarter of the 19th century,
and its last decade especially, saw a marked advance in technique, until
it became a common thing to find as much deep and quiet play embodied in
a single first-class problem as in three or four of the old-time
problems, and hence arose the practice of blending several distinct
ideas in one elaborate whole.

In the composition of "two-movers" it is customary to allow greater
elasticity and a less rigorous application of the principles of purity
and economy. By this means a greater superficial complexity is attained;
but the Teutonic and Bohemian schools, and even English and American
two-move specialists, recognize that complexity, if it involves the
sacrifice of first principles, is liable to abuse. The blind master,
A.F. Mackenzie of Jamaica, however, with a few others (notably T.
Taverner, W. Gleave, H. and E. Bettman and P.F. Blake) have won some of
their greatest successes with problems which, under stricter ruling,
would not be allowed.

Bohemian (Czech) composers have long stood unrivalled as exponents of
that blending of ideas which is the distinguishing trait of the later
problem. Such is their skill in construction that it is rare to find in
a problem of the Bohemian school fewer than three or four lines of play
which, in economy and purity, are unimpeachable. Amongst the earliest
composers of this class Anton König, the founder of the school, Makovky,
Drtina, Palct and Pilnacek deserve to be honourably mentioned, but it
was not until the starting of a chess column in the weekly journal
_Svetozor_ that the merits of the new school were fully asserted. It was
in 1871 that Jan Dobrusky contributed his first composition to that
paper: he was followed by G. Chocholous, C. Kondelik, Pospisil, Dr
Mazel, Kviciala, Kesl, Tuzar, Musil and J. Kotrc; and later still,
Havel, Traxler and Z. Mach were no unworthy followers of Dobrusky.

The faculty for blending variations is not without "the defects of its
qualities," and consequently among the less able composers a certain
tendency to repeat combinations of similar companion ideas is
discernible at times, while the danger that facile construction might
usurp the place of originality and strategy was already apparent to
Chocholous when, in an article on the classification of chess problems
(_Deutsche Schachzeitung_, 1890), he warned the younger practitioners of
the Bohemian school against what has been dubbed by H. Von Gottschall
_Varianten-leierei_, or "the grinding out of variations." When this one
reservation is made few will be inclined to dispute the pre-eminence of
the Bohemian school. To some tastes, however, a greater appeal is made
by the deeper play of the older German school, the quaint fancy of the
American composer Samuel Loyd, or the severity and freedom from "duals"
which mark the English composers.

The idea of holding a problem competition open to the world was first
mooted in connexion with the chess congress of 1851, but it was in 1854
that a tourney (confined to British composers) was first held. Since
then a number of important problem tournaments have been held.

_History of Chess._

The origin of chess is lost in obscurity. Its invention has been
variously ascribed to the Greeks, Romans, Babylonians, Scythians,
Egyptians, Jews, Persians, Chinese, Hindus, Arabians, Araucanians,
Castilians, Irish and Welsh. Some have endeavoured to fix upon
particular individuals as the originators of the game; amongst others
upon Japheth, Shem, King Solomon, the wife of Ravan, king of Ceylon, the
philosopher Xerxes, the Greek chieftain Palamedes, Hermes, Aristotle,
the brothers Lydo and Tyrrhene, Semiramis, Zenobia, Attalus (d. c. 200
B.C.), the mandarin Hansing, the Brahman Sissa and Shatrenscha, stated
to be a celebrated Persian astronomer. Many of these ascriptions are
fabulous, others rest upon little authority, and some of them proceed
from easily traceable errors, as where the Roman games of _Ludus
Latrunculorum_ and _Ludus Calculorum_, the Welsh recreation of
_Tawlbwrdd_ (throw-board) and the ancient Irish pastime of _Fithcheall_
are assumed to be identical with chess; so far as the Romans and Welsh
are concerned, the contrary can be proved, while from what little is
known of the Irish game it appears not to have been a sedentary game at
all. The claims of the Chinese were advocated in a letter addressed by
Mr Eyles Irwin in 1793 to the earl Charlemont. This paper was published
in the _Transactions of the Royal Irish Academy_, and its purport was
that chess, called in the Chinese tongue _chong-ki_ (the "royal game")
was invented in the reign of Kao-Tsu, otherwise Lin-Pang, then king, but
afterwards emperor of Kiang-Nang, by a mandarin named Han-sing, who was
in command of an army invading the Shen-Si country, and who wanted to
amuse his soldiers when in winter quarters. This invasion of the Shen-Si
country by Han-Sing took place about 174 B.C. Capt. Hiram Cox states
that the game is called by the Chinese _choke-choo-hong ki_, "the play
of the science of war." (See also a paper published by the Hon. Daines
Barrington in the 9th vol. of the _Archaeologia_.) Mr N. Bland,
M.R.A.S., in his _Persian Chess_ (London, 1850), endeavours to prove
that the Persians were the inventors of chess, and maintains that the
game, born in Persia, found a home in India, whence after a series of
ages it was brought back to its birthplace. The view, however, which has
obtained the most credence, is that which attributes the origin of chess
to the Hindus. Dr Thomas Hyde of Oxford, writing in 1694 (_De Ludis
Orientalibus_), seems to have been the first to propound this theory,
but he appears to have been ignorant of the game itself, and the
Sanskrit records were not accessible in his time. About 1783-1789 Sir
William Jones, in an essay published in the 2nd vol. of _Asiatic
Researches_, argued that Hindustan was the cradle of chess, the game
having been known there from time immemorial by the name of
_chaturanga_, that is, the four _angas_, or members of an army, which
are said in the _Amarakosha_ to be elephants, horses, chariots and foot
soldiers. As applicable to real armies, the term _chaturanga_ is
frequently used by the epic poets of India. Sir William Jones's essay is
substantially a translation of the _Bhawishya Purana_, in which is given
a description of a four-handed game of chess played with dice. A pundit
named Rhadhakant informed him that this was mentioned in the oldest law
books, and also that it was invented by the wife of Ravan, king of Lanka
(Ceylon), in the second age of the world in order to amuse that monarch
while Rama was besieging his metropolis. This account claims for chess
an existence of 4000 or 5000 years. Sir William, however, grounds his
opinions as to the Hindu origin of chess upon the testimony of the
Persians and not upon the above manuscript, while he considers the game
described therein to be more modern than the Persian game. Though sure
that the latter came from India and was invented there, he admits that
he could not find any account of it in the classical writings of the
Brahmans. He lays it down that chess, under the Sanskrit name
_chaturanga_, was exported from India into Persia in the 6th century of
our era; that by a natural corruption the old Persians changed the name
into _chatrang_, but when their country was soon afterwards taken
possession of by the Arabs, who had neither the initial nor final letter
of the word in their alphabet, they altered it further into _shatranj_,
which name found its way presently into modern Persian and ultimately
into the dialects of India.

Capt. Hiram Cox, in a letter upon Burmese chess, written in 1799 and
published in the 7th vol. of _Asiatic Researches_, refers to the above
essay, and considers the four-handed game described in the Sanskrit
manuscript to be the most ancient form of chess, the Burmese and Persian
games being second and third in order of precedence. Later, in the 11th
and 24th vols. of the _Archaeologia_, Mr Francis Douce and Sir Frederick
Madden expressed themselves in favour of the views held by Hyde and his
followers.

In Professor Duncan Forbes's _History of Chess_ (1860) Capt. Cox's
views, as founded upon Sir William Jones's Sanskrit manuscript, are
upheld and are developed into an elaborate theory. Professor Forbes
holds that the four-handed game of _chaturanga_ described in the
_Bhawishya Purana_ was the primeval form of chess; that it was invented
by a people whose language was Sanskrit (the Hindus); and that it was
known and practised in India from a time lost in the depths of a remote
antiquity, but for a period the duration of which may have been from
3000 to 4000 years before the 6th century of the Christian era. He
endeavours to show, but adduces no proof, how the four armies commanded
by four kings in Sir William Jones's manuscript became converted into
two opposing armies, and how two of the kings were reduced to a
subordinate position, and became "monitors" or "counsellors," one
standing by the side of the White and the other of the Black king, these
counsellors being the _farzins_ from which we derive our "queens." Among
other points he argues, apparently with justice, that _chaturanga_ was
evidently the root of _shatranj_, the latter word being a mere exotic in
the language of the inhabitants of Persia.

Van der Linde, in his exhaustive work, _Geschichte und Litteratur des
Schachspiels_ (Berlin, 1874), has much to say of the origin-theories,
nearly all of which he treats as so many myths. He agrees with those who
consider that the Persians received the game from the Hindus; but the
elaborate _chaturanga_ theories of Forbes receive but scant mercy. Van
der Linde argues that _chaturanga_ is always used by the old Indian
poets of an army and never of a game, that all Sanskrit scholars are
agreed that chess is not mentioned in really ancient Hindu records; that
the _Puranas_ generally, though formerly considered to be extremely old,
are held in the light of modern research to reach no farther back than
the 10th century--while the copies of the _Bhawishya Purana_ in the
British Museum and the Berlin Library do not contain the extract relied
upon by Forbes, though it is to be found in the _Raghunandana_, which
was translated by Weber in 1872, and is stated by Bühler to date from
the 16th century. The outcome of van der Linde's studies appears to be
that chess certainly existed in Hindustan in the 8th century, and that
probably that country is the land of its birth. He inclines to the idea
that the game originated among the Buddhists, whose religion was
prevalent in India from the 3rd to the 9th century. According to their
ideas, war and the slaying of one's fellow-men, for any purposes
whatever, is criminal, and the punishment of the warrior in the next
world will be much worse than that of the simple murderer; hence chess
was invented as a substitute for war. In opposition to Forbes,
therefore, and in agreement with Sir William Jones, van der Linde takes
the view that the four-handed game of the original manuscript is a
comparatively modern adaptation of the Hindu chess, and he altogether
denies that there is any proof that any form of the game has the
antiquity attributed to it. Internal evidence certainly seems to
contradict the theory that Sir William Jones's manuscript is very
ancient testimony; for it mentions two great sages, Vyasa and Gotama,
the former as teaching _chaturanga_ to Prince Yudhishthira, and the
other as giving an opinion upon certain principles of the game; but this
could not well be, seeing that it was played with dice, and that all
games of hazard were positively forbidden by Manu. It would appear also
that Indian manuscripts are not absolutely trustworthy as evidence of
the antiquity of their contents; for the climate has the effect of
destroying such writings in a period of 300 or 400 years. They must,
therefore, be recopied from time to time and in this way later
interpolations may easily creep in.

Von der Lasa, who had, in an article prefixed to the _Handbuch_ in 1864,
accepted Forbes's views, withdrew his support in a review of the work
just noticed, published in the September and November numbers of the
_Deutsche Schachzeitung_, 1874, and expressed his adherence to the
opinions of van der Linde.

Altogether, therefore, we find the best authorities agreeing that chess
existed in India before it is known to have been played anywhere else.
In this supposition they are strengthened by the names of the game and
of some of the pieces. _Shatranj_, as Forbes has pointed out, is a
foreign word among the Persians and Arabians, whereas its natural
derivation from the term _chaturanga_ is obvious. Again _al-fil_, the
Arabic name of the bishop, means the elephant, otherwise _alephhind_,
the Indian ox. Our earliest authority on chess is Masudi, an Arabic
author who wrote about A.D. 950. According to him, _shatranj_ had
existed long before his time; and though he may speak not only for his
own generation but for a couple of centuries before, that will give to
chess an existence of over a thousand years.

_Early and Medieval Times._--The dimness which shrouds the origin of
chess naturally obscures also its early history. We have seen that chess
crossed over from India into Persia, and became known in the latter
country by the name of _shatranj_. Some have understood that word to
mean "the play of the king"; but undoubtedly Sir William Jones's
derivation carries with it the most plausibility. How and when the game
was introduced into Persia we have no means of knowing. The Persian poet
Firdusi, in his historical poem, the _Shahnama_, gives an account of the
introduction of _shatranj_ into Persia in the reign of Chosroes I.
Anushirwan, to whom came ambassadors from the sovereign of Hind (India),
with a chessboard and men asking him to solve the secrets of the game,
if he could, or pay tribute. Chosroes I. was the contemporary of
Justinian, and reigned in the 6th century A.D. Professor Forbes seems to
think that this poem may be looked upon as an authentic history. This
appears, however, to be somewhat dangerous, especially as Firdusi lived
some 450 years after the supposed event took place; but since other
Persian and Arabian writers state that _shatranj_ came into Persia from
India, there appears to be a consensus of opinion that may be considered
to settle the question. Thus we have the game passing from the Hindus to
the Persians and thence to the Arabians, after the capture of Persia by
the Caliphs in the 7th century, and from them, directly or indirectly,
to various parts of Europe, at a time which cannot be definitely fixed,
but either in or before the 11th century. That the source of the
European game is Arabic is clear enough, not merely from the words
"check" and "mate," which are evidently from _Shah mat_ ("the king is
dead"), but also from the names of some of the pieces. There are various
chess legends having reference to the 7th and 8th centuries, but these
may be neglected as historically useless; and equally useless appear the
many oriental and occidental romances which revolve around those two
great central figures, Harun al-Rashid and Charlemagne. There is no
proof that either of them knew anything of chess or, so far as the
latter is concerned, that it had been introduced into Europe in his
time. True, there is an account given in Gustavus Selenus, taken from
various old chronicles, as to the son of Prince Okar or Otkar of Bavaria
having been killed by a blow on the temple, struck by a son of Pippin
after a game of chess; and there is another well-known tradition as to
the magnificent chess-board and set of men said to have been sent over
as a present by the empress Irene to Charlemagne. But both tales are not
less mythical than the romance which relates how the great Frankish
monarch lost his kingdom over a game of chess to Guérin de Montglave;
for van der Linde shows that there was no Bavarian prince of the name of
Okar or Otkar at the period alluded to, and as ruthlessly shatters the
tradition about Irene's chessmen. With respect to Harun al-Rashid,
among the various stories told which connect him with chess, there is
one that at first sight may seem entitled to some degree of credit. In
the annals of the Moslems by Abulfeda (Abu'l Fida), there is given a
copy of a letter stated to be "From Nicephorus, emperor of the Romans,
to Harun, sovereign of the Arabs," which (using Professor Forbes's
translation) after the usual compliments runs thus:--"The empress
(Irene) into whose place I have succeeded, looked upon you as a _Rukh_
and herself as a mere Pawn; therefore she submitted to pay you a tribute
more than the double of which she ought to have exacted from you. All
this has been owing to female weakness and timidity. Now, however, I
insist that you, immediately on reading this letter, repay to me all the
sums of money you ever received from her. If you hesitate, the sword
shall settle our accounts." Harun's reply, written on the back of the
Byzantine emperor's letter, was terse and to the point. "In the name of
God the merciful and gracious. From Harun, the commander of the
faithful, to the Roman dog Nicephorus. I have read thine epistle, thou
son of an infidel mother; my answer to it thou shalt see, not hear."
Harun was as good as his word, for he marched immediately as far as
Heraclea, devastating the Roman territories with fire and sword, and
soon compelled Nicephorus to sue for peace. Now the points which give
authority to this narrative and the alleged correspondence are that the
relations which they assume between Irene and Nicephorus on the one hand
and the warlike caliph on the other are confirmed by the history of
those times, while, also, the straightforward brevity of Harun's reply
commends itself as what one might expect from his soldier-like
character. Still, the fact must be remembered that Abulfeda lived about
five centuries after the time to which he refers. Perhaps we may assume
that it is not improbable that the correspondence is genuine; but that
the words _rukh_ and _pawn_ may have been substituted for other terms of
comparison originally used.

As to how chess was introduced into western and central Europe nothing
is really known. The Spaniards very likely received it from their Moslem
conquerors, the Italians not improbably from the Byzantines, and in
either case it would pass northwards to France, going on thence to
Scandinavia and England. Some say that chess was introduced into Europe
at the time of the Crusades, the theory being that the Christian
warriors learned to play it at Constantinople. This is negatived by a
curious epistle of St Peter Damian, cardinal bishop of Ostia, to Pope
Alexander II., written about A.D. 1061, which, assuming its
authenticity, shows that chess was known in Italy before the date of the
first crusade. The cardinal, as it seems, had imposed a penance upon a
bishop whom he had found diverting himself at chess; and in his letter
to the pope he repeats the language he had held to the erring prelate,
viz. "Was it right, I say, and consistent with thy duty, to sport away
thy evenings amidst the vanity of chess, and defile the hand which
offers up the body of the Lord, and the tongue that mediates between God
and man, with the pollution of a sacrilegious game?" Following up the
same idea that statutes of the church of Elna, in the 3rd vol. of the
_Councils of Spain_, say, "Clerks playing at dice or chess shall be
_ipso facto_ excommunicated." Eudes de Sully, bishop of Paris under
Philip Augustus, is stated in the _Ordonn. des Rois de France_ to have
forbidden clerks to play the game, and according to the _Hist. Eccles._
of Fleury, St Louis, king of France, imposed a fine on all who should
play it. Ecclesiastical authorities, however, seemed to have differed
among themselves upon the question whether chess was or was not a lawful
game according to the canons, and Peirino (_De Proelat._ chap. 1) holds
that it was permissible for ecclesiastics to play thereat. Among those
who have taken an unfavourable view of the game may be mentioned John
Huss, who, when in prison, deplored his having played at chess, whereby
he had lost time and run the risk of being subject to violent passions.
Among authentic records of the game may be quoted the _Alexiad_ of the
princess Anna Comnena, in which she relates how her father, the emperor
Alexius, used to divert his mind from the cares of state by playing at
chess with his relatives. This emperor died in 1118.

Concerning chess in England there is the usual confusion between legend
and truth. Snorre Sturleson relates that as Canute was playing at chess
with Earl Ulf, a quarrel arose, which resulted in the upsetting of the
board by the latter, with the further consequence of his being murdered
in church a few days afterwards by Canute's orders. Carlyle, in _The
Early Kings of Norway_, repeats this tale, but van der Linde treats it
as a myth. The _Ramsey Chronicle_ relates how bishop Utheric, coming to
Canute at night upon urgent business, found the monarch and his
courtiers amusing themselves at dice and chess. There is nothing
intrinsically improbable in this last narrative; but Canute died about
1035, and the date, therefore, is suspiciously early. Moreover,
allowance must be made for the ease with which chroniclers described
other games as chess. William the Conqueror, Henry I., John and Edward
I. are variously stated to have played at chess. It is generally
supposed that the English court of exchequer took its name from the
cloth, figured with squares like a chess-board, which covered the table
in it (see EXCHEQUER). An old writer says that at the coronation of
Richard I. in 1189, six earls and barons carried a chess-board with the
royal insignia to represent the exchequer court. According to Edmonson's
_Heraldry_, twenty-six English families bore chess rooks in their coats
of arms.

As regards the individual pieces, the king seems to have had the same
move as at present; but it is said he could formerly be captured. His
"castling" privilege is a European invention; but he formerly leaped two
and even three squares, and also to his Kt 2nd. Castling dates no
farther back than the first half of the 16th century. The queen has
suffered curious changes in name, sex and power. In _shatranj_ the piece
was called _farz_ or _firz_ (also _farzan_, _farzin_ and _farzi_),
signifying a "counsellor," "minister" or "general." This was latinized
into _farzia_ or _fercia_. The French slightly altered the latter form
into _fierce_, _fierge_, and as some say, _vierge_, which, if true,
might explain its becoming a female. Another and much more probable
account has it that whereas formerly a pawn on reaching an eighth square
became a _farzin_, and not any other piece, which promotion was of the
same kind as at draughts (in French, _dames_), so she became a _dame_ or
queen as in the latter game, and thence _dama_, _donna_, &c. There are
old Latin manuscripts in which the terms _ferzia_ and _regina_ are used
indifferently. The queen formerly moved only one square diagonally and
was consequently the weakest piece on the board. The immense power she
now possesses seems to have been conferred upon her so late as about the
middle of the 15th century. It will be noticed that under the old system
the queens could never meet each other, for they operated on diagonals
of different colours. The bishop's scope of action was also very limited
formerly; he could only move two squares diagonally, and had no power
over the intermediate square, which he could leap over whether it was
occupied or not. This limitation of their powers prevailed in Europe
until the 15th century. This piece, according to Forbes, was called
among the Persians _pil_, an elephant, but the Arabs, not having the
letter _p_ in their alphabet, wrote it _fil_, or with their definite
article _al-fil_, whence _alphilus_, _alfinus_, _alifiere_, the latter
being the word used by the Italians; while the French perhaps get their
_fol_ and _fou_ from the same source. The pawns formerly could move only
one square at starting; their powers in this respect were increased
about the early part of the 16th century. It was customary for them on
arriving at an eighth square to be exchanged only for a _farzin_
(queen), and not any other piece; the rooks (so called from the Indian
_rukh_ and Persian _rokh_, meaning "a soldier") and the knights appear
to have always had the same powers as at present. As to the chessboards,
they were formerly uncoloured, and it is not until the 13th century that
we hear of checkered boards being used in Europe.

_Development in Play._--The change of _shatranj_ into modern chess took
place most probably first in France, and thence made its way into Spain
early in the 15th century, where the new game was called _Axedrez de la
dama_, being also adopted by the Italians under the name of _scacci
alla rabiosa_. The time of the first important writer on modern chess,
the Spaniard Ruy Lopez de Segura (1561), is also the period when the
latest improvement, castling, was introduced, for his book (_Libra de la
invention liberal y arte del juego del Axedrez_), though treating of it
as already in use, also gives the old mode of play, which allowed the
king a leap of two or three squares. Shortly afterwards the old
_shatranj_ disappears altogether. Lopez was the first who merits the
name of chess analyst. At this time flourished the flower of the Spanish
and Italian schools of chess--the former represented by Lopez, Ceron,
Santa Maria, Busnardo and Avalos; the latter by Giovanni Leonardo da
Cutri (il Puttino) and Paolo Boi (il Syracusano). In the years 1562-1575
both Italian masters visited Spain and defeated their Spanish
antagonists. During the whole 17th century we find but one worthy to be
mentioned, Giacchino Greco (il Calabrese). The middle of the 18th
century inaugurates a new era in chess. The leading man of this time was
François André Danican Philidor. He was born in 1726 and was trained by
M. de Kermur, Sire de Légal, the star of the _Cafe de la Régence_ in
Paris, which has been the centre of French chess ever since the
commencement of the 18th century. In 1747 Philidor visited England, and
defeated the Arabian player, Phillip Stamma, by 8 games to 1 and 1 draw.
In 1749 he published his _Analyse des échecs_, a book which went through
more editions and was more translated than any other work upon the game.
During more than half a century Philidor travelled much, but never went
to Italy, the only country where he could have found opponents of
first-rate skill. Italy was represented in Philidor's time by Ercole del
Rio, Lolli and Ponziani. Their style was less sound than that of
Philidor, but certainly a much finer and in principle a better one. As
an analyst the Frenchman was in many points refuted by Ercole del Rio
("the anonymous Modenese"). Blindfold chess-play, already exhibited in
the 11th century by Arabian and Persian experts, was taken up afresh by
Philidor, who played on many occasions three games simultaneously
without sight of board or men. These exhibitions were given in London,
at the Chess Club in St James's Street, and Philidor died in that city
in 1795. As eminent players of this period must be mentioned Count Ph.J.
van Zuylen van Nyevelt (1743-1826), and the German player, J. Allgaier
(1763-1823). after whom a well-known brilliant variation of the King's
Gambit is named. Philidor was succeeded by Alexandre Louis Honoré
Lebreton Deschapelles (1780-1847), who was also a famous whist player.
The only player who is known to have fought Deschapelles not
unsuccessfully on even terms is John Cochrane. He also lost a match
(1821) to W. Lewis, to whom he conceded the odds of "pawn and move," the
Englishman winning one and drawing the two others. Deschapelles'
greatest pupil, and the strongest player France ever possessed, was
Louis Charles Mahé de la Bourdonnais, who was born in 1797 and died in
1840. His most memorable achievement was his contest with the English
champion, Alexander Macdonnell, the French player winning in the
proportion of three to two.

The English school of chess began about the beginning of the 19th
century, and Sarratt was its first leader. He flourished from 1808 to
1821, and was followed by his great pupil, W. Lewis, who will be
principally remembered for his writings. His literary career belongs to
the period from 1818 to 1848 and he died in 1869. A. Macdonnell
(1798-1835) has been already mentioned. To the same period belong also
Captain Evans, the inventor of the celebrated "Evans Gambit" (1828), who
died at a very advanced age in 1873; Perigal, who participated in the
correspondence matches against Edinburgh and Paris; George Walker, for
thirty years chess editor of _Bell's Life in London_; and John Cochrane,
who met every strong player from Deschapelles downwards. In the same
period Germany possessed but one good player, J. Mendheim of Berlin. The
fifth decade of the 19th century is marked by the fact that the
leadership passed from the French school to the English. After the death
of la Bourdonnais, Fournié de Saint-Amant became the leading player in
France; he visited England in the early part of 1843, and successfully
met the best English players, including Howard Staunton (q.v.); but the
latter soon took his revenge, for in November and December 1843 a great
match between Staunton and Saint-Amant took place in Paris, the English
champion winning by 11 games to 6 with 4 draws. During the succeeding
eight years Staunton maintained his reputation by defeating Popert,
Horwitz and Harrwitz. Staunton was defeated by Anderssen at the London
tournament in 1851, and this concluded his match-playing career. Among
the contemporaries of Staunton may be mentioned Henry Thomas Buckle,
author of the _History of Civilization_, who defeated Kieseritzki,
Anderssen and Löwenthal.

In the ten years 1830-1840 a new school arose in Berlin, the seven
leaders of which have been called "The Pleiades." These were Bledow
(1795-1846), Bilguer (1815-1840), Hanstein (1810-1850), Mayet
(1810-1868), Schorn (1802-1850), B. Horwitz (b. 1809) and von
Heydebrandt und der Lasa, once German ambassador at Copenhagen. As
belonging to the same period must be mentioned the three Hungarian
players, Grimm, Szen and J. Löwenthal.

Among the great masters since the middle of the 19th century Paul Morphy
(1837-1884), an American, has seldom been surpassed as a chess player.
His career was short but brilliant. Born in New Orleans in 1837, he was
taught chess by his father when only ten years of age, and in two years'
time became a strong player. When not quite thirteen he played three
games with Löwenthal, and won two of them, the other being drawn. He was
twenty years of age when he competed in the New York congress of 1857,
where he won the first prize. In 1858 he visited England, and there
defeated Boden, Medley, Mongrédien, Owen, Bird and others. He also beat
Löwenthal by 9 games to 3 and 2 drawn. In the same year he played a
match at Paris with Harrwitz, winning by 5 to 2 and 1 drawn; and later
on he obtained a victory over Anderssen. On two or three occasions he
played blindfold against eight strong players simultaneously, each time
with great success. He returned to America in 1859 and continued to
play, but with decreasing interest in the game, until 1866. He died in
1884.

Wilhelm Steinitz (b. 1836) took the sixth prize at the London congress
of 1862. He defeated Blackburne in a match by 7 to 1 and 2 drawn. In
1866 he beat Anderssen in a match by 8 games to 6. In 1868 he carried
off the first prize in the British Chess Association handicap, and in
1872 in the London grand tourney, also defeating Zukertort in a match by
7 games to 1 and 4 drawn. In 1873 he carried off the first prize at the
Vienna congress; and in 1876 he defeated Blackburne, winning 7 games
right off. In 1872-1874, in conjunction with W.N. Potter, he conducted
and won a telegraphic correspondence match for London against Vienna. In
Philidor's age it was considered almost incredible that he should be
able to play three simultaneous games without seeing board or men, but
Paulsen, Blackburne and Zukertort often played 10 or 12 such games,
while as many as 14 and 15 have been so played.

In 1876 England was in the van of the world's chess army. English-born
players then were Boden, Burn, Macdonnell, Bird, Blackburne and Potter;
whilst among naturalized English players were Löwenthal, Steinitz,
Zukertort, who died in 1888, and Horwitz. This illustrious contingent
was reinforced in 1878 by Mason, an Irish-American, who came over for
the Paris tournament; by Gunsberg, a Hungarian; and later by Teichmann,
who also made England his home. English chess flourished under the
leadership of these masters, the chief prizes in tournaments being
consistently carried off by the English representatives.

To gauge the progress made by the game since about 1875 it will suffice
to give the following statistics. In London Simpson's Divan was formerly
the chief resort of chess players; the St George's Chess Club was the
principal chess club in the West End, and the City of London Chess Club
in the east. About a hundred or more clubs are now scattered all over
the city. Formerly only the British Chess Association existed; after its
dissolution the now defunct Counties' Chess Association took its place,
and this was superseded by the re-establishment by Mr Hoffer of the
British Chess Association, which again fell into abeyance after having
organized three international tournaments--London, 1886; Bradford, 1888;
and Manchester, 1890--and four national tournaments. There were various
reasons why the British Chess Association ceased to exercise its
functions, one being that minor associations did not feel inclined to
merge their identity in a central association. The London League was
established, besides the Northern Chess Union, the Southern Counties'
Chess Union, the Midland Counties' Union, the Kent County Association;
and there are associations in Surrey, Sussex, Essex, Hampshire,
Wiltshire, Gloucestershire, Somersetshire, Cambridgeshire,
Herefordshire, Leicestershire, Northamptonshire, Staffordshire,
Worcestershire and Lancashire. All these associations are supported by
the affiliated chess clubs of the respective counties. Scotland (which
has its own association), Wales and Ireland have also numerous clubs.

Still, England did not produce one new eminent player between 1875 and
1905. First-class chess remained in the hands of the veterans Burn,
Blackburne, Mason and Bird. The old amateurs passed away, their place
being taken by a new generation of powerful amateurs, so well equipped
that Great Britain could hold its own in an amateur contest against the
combined forces of Germany, Austria, Holland and Russia. The terms
_master_ and _amateur_ are not used in any invidious sense, but simply
as designating, in the former case, first-class players, and in the
latter, those just on the borderland of highest excellence. The
professional element as it existed in the heydey of Simpson's Divan
almost disappeared, the reason being the increased number of chess
clubs, where enthusiasts and students might indulge in their favourite
pastime to their heart's content, tournaments with attractive prizes
being arranged during the season. The former occupation of the masters
vanished in consequence; the few who remained depended upon the passing
visitors from the provinces who were eager to test their strength by the
standard of the master. Blackburne visited the provinces annually,
keeping the interest in first-class chess alive by his simultaneous play
and his extraordinary skill as a blindfold player--unsurpassed until the
advent of Harry Nelson Pillsbury (1872-1906), the leading American
master since Morphy.

Germany has produced great chess players in Tarrasch, E. Lasker, Lipke,
Fritz, Bardeleben, Walbrodt and Mieses, besides a goodly number of
amateurs. Austria produced Max Weiss, Schlechter, Marco and Hruby, to
say nothing of such fine players as the Fleissigs, Dr Mertner, Dr
Kaufmann, Fahndrich, Jacques Schwarz and others. Hungary was worthily
represented by Maroczy, Makovetz and Brody, Maroczy being the best after
Charousek's death. Russia, having lost Jaenisch, Petroff and Schumoff,
discovered Tchigorin, Janowsky, Schiffers, Alapin, Winawer and
Taubenhaus. France showed a decline for many years, having only the
veteran M. Arnous de Rivière and the naturalized M. Rosenthal left,
followed by Goetz and two good amateurs, MM. Didier and Billecard. Italy
had only Signer Salvioli, although Signer Reggio came to the fore.
Holland had a fair number of players equal to the English amateurs, but
no master since the promising young van Lennep died.

The first modern International Chess Tournament held in London in 1851
was the forerunner of various similar contests of which the following is
a complete table:--

_Tournaments_.

  1851. London. 1 Anderssen, 2 Wyvill, 3 Williams.
  1857. Manchester. 1 Lowenthal, 2 Anderssen.
  1857. New York. 1 Morphy, 2 L. Paulsen.
  1858. Birmingham. 1 Lowenthal, 2 Falkbeer.
  1860. Cambridge. 1 Kolisch, 2 Stanley.
  1861. Bristol, 1 L. Paulsen, 2 Boden.
  1862. London, 1 Anderssen, 2 L. Paulsen, 3 Owen.
  1865. Dublin. 1 Steinitz, 2 MacDonnell.
  1866. Redcar. De Vere.
  1866. English Championship Cup. De Vere.
  1866. British Chess Association. 1 Steinitz, 2 Green.
  1867. Paris. 1 Kolisch, 2 Winawer, 3 Steinitz.
  1867. Dundee. 1 Neumann, 2 Steinitz, 3 De Vere and MacDonnell.
  1868. English Championship Cup. 1 Blackburne, 2 De Vere.
  1868. British Chess Association Handicap. 1 Steinitz, 2 Wisker,
         3 Blackburne.
  1870. Baden-Baden. 1 Anderssen, 2 Steinitz, 3 Blackburne and Neumann.
  1870. English Championship Cup. 1 Wisker, 2 Burn.
  1870-1871. City of London Handicap. 1 Potter, 2 De Vere.
  1871-1872. City of London Handicap. 1 Steinitz, 2 Keats.
  1872. London. 1 Steinitz, 2 Blackburne, 3 Zukertort.
  1872. English Championship Cup. 1 Wisker (becoming permanent holder
          of the cup), 2 De Vere.
  1873. Vienna. 1 Steinitz, 2 Blackburne, 3 Anderssen.
  1876. London. 1 Blackburne, 2 Zukertort, 3 Potter.
  1878. Paris. 1 Zukertort, 2 Winawer (after a tie with Zukertort),
          3 Blackburne.
  1880. Wiesbaden. 1, 2, and 3, a tie between Blackburne, Englisch and
          A. Schwarz.
  1881. Berlin. 1 Blackburne, 2 Zukertort, 3 Tchigorin and Winawer.
          Tchigorin made his first public appearance in this contest.
  1882. Vienna. 1 Steinitz and Winawer, 3 Mason.
  1883. London. 1 Zukertort, 2 Steinitz, 3 Blackburne.
  1883. Nuremberg. 1 Winawer, 2 Blackburne, 3 Mason. This tournament is
          a milestone in modern chess history. The prizes being
          comparatively small, it was thought that it necessarily must
          be a failure, the munificently endowed London tournament
          having just been completed. But, strange to say, whilst in
          London fourteen players competed, there were nineteen entries
          in Nuremberg. Winawer, not placed in the former, won the first
          prize in the latter.
  1885. Hamburg. 1 Gunsberg; the next prizes were divided by Blackburne,
          Mason, Englisch, Tarrasch and Weiss.
  1885. Hereford. 1 Blackburne, 2 and 3 Bird and Schallopp.
  1886. London. 1 Blackburne, 2 Burn, 3 Gunsberg and Taubenhaus.
  1886. Nottingham. 1 Burn, 2 Schallopp, 3 Gunsberg and Zukertort.
  1887. Frankfort. 1 Mackenzie, 2 Blackburne and Weiss.
  1888. Bradford. 1 Gunsberg, 2 Mackenzie, 3 Mason and Bardeleben.
  1889. New York. 1 Tchigorin and Weiss, 3 Gunsberg.
  1889. Breslau. 1 Tarrasch, 2 Burn, 3 Weiss.
  1890. Amsterdam. 1 Burn, 2 Lasker, 3 Mason. There were only nine
          competitors, Lasker unexpectedly losing to van Vliet by a trap.
  1890. Manchester. 1 Tarrasch, 2 Blackburne, 3 Bird and Mackenzie.
  1892. Dresden. 1 Tarrasch, 2 Makovetz and Forges. Blackburne received
          a special prize.
  1894. Leipzig. 1 Tarrasch, 2 Lipke and Teichmann.
  1895. Hastings. 1 Pillsbury, 2 Tchigorin, 3 Lasker. This tournament
          is historical for the first appearance of Pillsbury, the
          American champion, and Maroczy, the Hungarian champion.
  1896. Nuremberg. 1 Lasker, 2 Maroczy, 3 Pillsbury and Tarrasch.
  1896. Budapest. 1 Tchigorin, 2 Charousek, 3 Pillsbury.
  1897. Berlin. 1 Charousek, 2 Walbrodt, 3 Blackburne. Englisch had to
          abandon the tournament and return to Vienna ill. He never
          recovered and died a few weeks later.
  1898. Vienna. 1 Tarrasch, 2 Pillsbury, 3 Janowsky. Tarrasch
          achieved a remarkable victory in this important tournament.
          Pillsbury's chances were better than his, but he managed
          to run him neck and neck and beat him in the tie match
          which followed.
  1898. Cologne. 1 Burn, 2 Charousek, Cohn and Tchigorin.
  1899. London. 1 Lasker, 2 Janowsky, Maroczy and Pillsbury.
          Janowsky sacrificed the second prize by trying to win a
          game against Steinitz when with an easy draw in hand he
          could have secured the second place for himself alone.
  1900. Munich. Tie between Maroczy, Pillsbury and Schlechter for
          three chief prizes.
  1900. Paris, 1 Lasker, 2 Pillsbury, 3 Maroczy and Marshall.
  1901. Monte Carlo. 1 Janowsky, 2 Schlechter, 3 Scheve and
          Tehigorin. A novel rule was introduced at this tournament,
          viz. the first drawn game to count ¼ to each player, to be
          replayed, and in case of a draw again to count ¼ each, and
          in case of win ½ to the winner. Theoretically this seems
          logical, but in practice it did not work well.
  1902. Monte Carlo. 1 Pillsbury and Maroczy, 3 Janowsky.
  1902. Hanover. 1 Janowsky, 2 Pillsbury, 3 Atkins.
  1903. Monte Carlo. 1 Tarrasch, 2 Maroczy, 3 Pillsbury.
  1904. Monte Carlo. 1 Maroczy, 2 Schlechter, 3 Marshall.
  1904. Cambridge Springs, 1 Marshall, 2 Lasker and Janowsky.
  1905. Ostend. 1 Maroczy, 2 Tarrasch and Janowsky.
  1905. Scheveningen. 1 Marshall, 2 Leussen, 3 Spielmann.
  1906. Stockholm. 1 Schlechter and Bernstein, 3 Mieses.
  1906. Ostend. 1 Schlechter, 2 Maroczy, 3 Rubenstein.
  1906. Nuremberg, 1 Marshall, 2 Duras, 3 Schlechter and Fleischmann.
  1907. Vienna, 1 Mieses, 2 Duras, 3 Maroczy and Vidmare.
  1907. Ostend. 1 Bernstein and Rubenstein, 3 Mieses.
  1907. Ostend. 1 Tarrasch, 2 Schlechter, 3 Janowsky and Marshall.
  1907. Carlsbad. 1 Rubenstein, 2 Maroczy, 3 Niemzowitch and Leonhardt.

In the absence of any recognized authority to confer the title of chess
champion of the world, it has usually been appropriated by the most
successful competitor in tournaments. On this ground Tarrasch claimed
the title in 1907, although Lasker, who had twice beaten Steinitz, the
previous champion, in championship matches, in addition to such masters
as Bird, Blackburne, Mieses and Marshall, was well qualified to assume
it. Accordingly in arranging the programme for the tournament at Ostend
in 1907 it was agreed that the winner of this contest should receive the
title of tournament champion, and should play a match with Lasker for
the championship of the world. Tarrasch having proved successful at
Ostend, the match between him and Lasker was played at Munich in
September 1908, and resulted in the victory of Lasker by 8 games to 3
and 5 draws.

Chess has developed various schools of play from time to time. The
theory of the game, however, did not advance in proportion to the
enormous strides in its popularity. Formerly the theory of play had been
enriched by such enthusiasts as Dr Max Lange, Louis Paulsen, Professor
Anderssen, Neumann, Dr Suhle, Falkbeer, Kieseritzki, Howard Staunton, Dr
Zukertort, W. N. Potter and Steinitz, foremost amongst them being Louis
Paulsen. The openings were thoroughly overhauled, new variations
discovered and tested in practical play over the board. These are now
things of the past. The masters who find flaws in old variations and
discover new ones bring them to light only in matches or tournaments, as
new discoveries have now a market value and may gain prizes in matches
or tournaments. The old "romantic" school consequently became extinct,
and the eliminating process resulted in the retention of a small
répertoire only, sufficient for practical purposes in important
contests. Gambits and kindred openings containing elements of chance
were avoided, and the whole stock which a first-class player requires is
a thorough knowledge of the "Ruy Lopez," the "Queen's Pawn Openings,"
and the "French" and "Sicilian Defences"--openings which contain the
least element of chance. The _répertoire_ being restricted it
necessarily follows that the scope for grand combinations is also
diminished and only strategy or position play remains. The "romantic"
school invariably aimed at an attack on the king's position at any cost;
nowadays the struggle is to obtain a minute advantage, and the whole
plan consists in finding or creating a weak spot in the opponent's
arrangement of forces; such is the theory of the modern school,
conceived and advocated by Steinitz. But it is a curious fact that
Steinitz founded the modern school rather late in life. He felt his
powers of combination waning, and being the world's champion and eager
to retain that title, he started the new theory. This novel departure
revolutionized chess entirely. The attacking and combination style was
sacrificed to a sound, sober and dry method; but Steinitz, strange to
say, was not even the best exponent of his own theory, this position
falling to younger players, Siegbert Tarrasch, Schlechter, Amos Burn and
Emanuel Lasker. Pillsbury and Janowsky adhered to both styles, the
former in a high degree, and so did Zukertort and Charousek; Tchigorin
being a free-lance with a style of his own. The old charm of the game
disappeared--in match and tournament play at least--and beauty was
sacrificed to exact calculation and to scoring points. This is to be
regretted, for the most beautiful games still occur when a player
resorts to the gambits. One of the finest games in the Hastings
tournament was played by Tchigorin against Pillsbury, and this was a
"King's Gambit Declined." Charousek won a "Bishop's Gambit" against Dr
Lasker in the Nuremberg tournament; and some brilliant games occur in
the "Queen's Gambit Declined," if either White or Black sacrifices the
KP. Another reason why gambits should be adopted by players in
tournaments is that competitors would necessarily be readily prepared
for the regulation openings, so that the gambits might take them by
surprise. After all, the new school is a natural consequence of the
progress of the game. Paulsen, Anderssen and Tchigorin devoted a
lifetime to the Evans Gambit, volumes of analyses were written on it,
and then Lasker revives an obsolete defence, and the Evans Gambit
disappears! Zukertort achieved a great success with "1. Kt to KB3" in
the London tournament, 1883, and this, or the kindred "1. P to Q4"
opening, has since become the trusty weapon in serious encounters.
Lasker wrote _Common Sense in Chess_, and gave the best defences of the
Ruy Lopez (a certain form of it); but the "common sense" was demolished
in the Paris and Nuremberg tournaments, and old forms of that remarkable
opening have to be refurbished. These instances will suffice to show the
reason for the cautious style of modern times. The Moltkes have replaced
the Napoleons.

The old versatility of style could be revived if club tournaments were
organized differently. The players might be compelled to adopt one
single opening only in a two-round contest, each player thus having
attack and defence in turn. The next season another opening would form
the programme, and so on. Even in international tournaments this
condition might be imposed; the theory would be enriched; full scope
would be given to power of combination and ingenuity; whilst the game
would be more interesting.

There are still amateurs who devote their energies to the theory of the
game; but so long as innovations or new discoveries are not tested by
masters in serious games, they are of no value. Steinitz used to keep a
number of new discoveries ready to be produced in masters' contests, the
result being that his novelties were regularly demolished when it came
to a practical test. The mistake was that he did not try his novelties
over the board with an opponent of equal strength, instead of trusting
to his own judgment alone.

The British Chess Federation was instituted in 1904, its first congress
being held at Hastings in that year, when a British championship, a
ladies' championship and a first-class amateur tournament were played.
These competitions have been continued annually at the congresses of the
federation, with the following results:--

_British Championship_.

  1904, Hastings, 1 H.E. Atkins and W.E. Napier, 3 J.H. Blackburne.
  1905. Southport. 1 H.E. Atkins, 2 G.E.H. Bellingham and J.H. Blackburne.
  1906. Shrewsbury. 1 H.E. Atkins, 2 R.P. Michell, 3 G.E. Wainwright.
  1907. Crystal Palace. 1 H.E. Atkins, 2 J.H. Blackburne, R.P. Michell,
          E. G. Sergeant and G. E. Wainwright.

_Ladies' Championship_.

  1904. Hastings. 1 Miss Finn, 2 Mrs Anderson and Mrs Herring.
  1905. Southport. 1 Miss Finn. 2 Mrs Anderson and Mrs Houlding.
  1906. Shrewsbury. 1 Mrs Herring, 2 Mrs Anderson, 3 Miss Ellis and Mrs
          Houlding.
  1907. Crystal Palace. 1 Mrs Herring and Mrs Houlding, 3 Mrs Anderson.

_First Class Amateur Tournament_.

  1904. Hastings Section A.   1 W.H. Gunston, 2 H.F. Cheshire and F.
                   Brown.
                 Section B.   1 G.E. Wainwright and C.H. Sherrard,
                   3 W.P. M'Bean.
  1905. Southport Section A.   1 Dr Holmes, 2 J. Mortimer, 3 H.G. Cole
                   and J.E. Purry.
                  Section B.   1 F.E. Hammond, 2 F. Brown. T.J. Kelly
                   and C.H. Wallwork.
  1906. Shrewsbury. 1 G. Shories, J. F. Allcock, P. W. Fairweather and
                   E. D. Palmer.

In 1896 and following years matches between representative players of
Great Britain and the United States respectively were played by cable,
with the following results:--

  1896. America       won by 4½ games to 3½
  1897. Great Britain    "   5½      "   4½
  1898. Great Britain    "   5½      "   4½
  1899. America          "   6       "   4
  1900. America          "   6       "   4
  1901. Drawn
  1902. America          "   5½      "   4½
  1903. America          "   5½      "   4½
  1907. Great Britain    "   5½      "   4½
  1908. America          "   6½      "   3½
  1909. Great Britain    "   6       "   4

Since 1899 cable matches have also been played annually between
representatives of English and American universities; of the first six
three were won by England, the remaining three being drawn. In England
chess matches have been played annually since 1873 between the
universities of Oxford and Cambridge, seven players on each side. Up to
1907 Oxford won eleven matches, Cambridge twenty-one, and three were
drawn.

  LITERATURE OF THE GAME.--The first known writer on chess was Jacobus
  de Cessolis (Jacopo Dacciesole), whose main object, however, though he
  gives the moves, &c., was to teach morals rather than chess. He was a
  Dominican friar, and his treatise, _Solatium Ludi Scacchorum,
  scilicet, Libellus de Moribus Hominum et Officiis Nobilium_, was
  written before the year 1200. It was afterwards translated into
  French, and in the year 1474 Caxton, under the title of _The Game and
  Playe of Chesse_, printed an English translation of the French
  version.

  In 1490 we have the _Göttinger Handschrift_, a work containing nine
  different openings and fifty problems. The author of this manuscript
  is not known. Then comes Vicent, a Spanish writer, whose book bears
  date 1495. Only the title-page has been preserved, the rest of the
  work having been lost in the first Carlist war. Of Lucena, another
  Spanish author who wrote in or about 1497, we are better informed. His
  treatise, _Repeticion des Amores y Arte de Axedres_, comprises various
  practical chess matters, including 150 positions, illustrated by 160
  well-executed woodcuts. Various of these positions are identical with
  those in the _Göttinger Handschrift_.In the 16th century works upon
  the game were written by Damiano, Ruy Lopez and Horatio Gianutio della
  Mantia; in the 17th century by Salvio, Polerio, Gustavus Selenus,
  Carrera, Greco, Fr. Antonio and the authors of the _Traité de
  Lausanne_; in the 18th century by Bertin, Stamma, Ercole del Rio,
  Lolli, Cozio, Philidor, Ponziani, Stein, van Nyevelt, Allgaier and
  Peter Pratt; in the 19th century by J.F.W. Koch and C.F. Koch,
  Sarratt, John Cochrane, Wm. Lewis, Silberschmidt, Ghulam Kassim and
  James Cochrane, George Walker, A. MacDonnell, Jaenisch, Petroff, von
  Bilguer, von der Lasa, Staunton, Kling and Horwitz, Bledow, Dubois,
  Kieseritzki, Max Lange, Löwenthal, Dufresne, Neumann, Suhle,
  Zukertort, Preti and others.

  English chess owes much to W. Lewis and George Walker. But to Howard
  Staunton must be ascribed the most important share in creating the
  later popularity which the game achieved in England. Staunton's first
  work, _The Chess Player's Handbook_, was published in 1847, and again
  (revised) in 1848. For want of further adequate revision many of its
  variations are now out of date; but taking the handbook as it was when
  issued, very high praise must be bestowed upon the author. His other
  works are: _The Chess Player's Text-Book_ and _The Chess Player's
  Companion_ (1849) (the latter being a collection of his own games),
  the _Chess Praxis_ (1860), republished in 1903, his posthumous Work,
  _Chess Theory and Practice_, edited by R.B. Wormald (1876), and
  various smaller treatises. The laws of the game as laid down in the
  _Praxis_ formed the basis of the rules adopted by the British Chess
  Association in 1862. Besides editing _The Chess Player's Chronicle_
  and _The Chess World_, he was the chess editor of _The Illustrated
  London News_ from 1844 till his death in 1874.

  Among continental chess authorities von Heydebrandt und der Lasa (more
  usually known by his second title) stood pre-eminent. The German
  _Handbuch_ was completed in 1843 by von Bilguer, who died before the
  first edition was completed. The second, third, fourth and fifth
  editions (the last published in 1874) were edited and revised by von
  der Lasa.

  Among the more important modern works the following may be mentioned:
  Vasquez, _El Ajedrez de memoria; La Odisea de Pablo Morphy_ (Havana,
  1893); Bauer, _Schachlexikon_ (Leipzig, 1893); Jean Dufresne, _Kleines
  Lehrbuch des Schachspiels_ (6th ed., Leipzig, 1893); E. Freeborough
  and Rev. C.E. Ranken, _Chess Openings, Ancient and Modern_; Arnelung,
  _Baltische Schachblätter, &c._ (Berlin, 1893); Bachman, _Geistreiche
  Schachpartien_ (containing a number of brilliant games) (Ansbach,
  1893-1899); E.H. Bird, _Chess History and Reminiscences_ (London,
  1893); _The Steinitz-Lasker Match_ (1894); _Chess Novelties_ (1895);
  Max Lange, _Paul Morphy_ (1894); C. Bardeleben and J. Mieses,
  _Lehrbuch des Schachspiels_ (very useful); Jas. Mason, _The Principles
  of Chess in Theory and Practice_ (1894); _The Art of Chess_ (1895);
  _Social Chess_ (Horace Cox, London); Dr Tarrasch, _Dreihundert
  Schachpartien_ (Leipzig, 1895); Dr Eugen V. Schmidt, _Syslematische
  Anordung von Schacheröffnungen_ (Veit & Co., Leipzig, 1895); Numa
  Preti, _A B C des échecs_ (Paris, 1895); C. Salvioli, _Teoria generate
  del giuoco degli Scacchi_ (Livorno, 1895): W. Steinitz, _Modern Chess
  Instructor_ (New York, 1895); L. Hoffer, _Chess_ (Routledge); E.
  Freeborough, _Select Chess End-Games_ (London, 1895); Euclid, _The
  Chess Ending King and Queen against King and Rook_ (London, 1895);
  Tassilo von Heydebrandt und der Laaa, _Leitfaden des Schachspiels_ and
  _Zur Geschichte und Literatur des Schachspiels_ (Leipzig, 1897); Dr.
  Lasker, _Common Sense in Chess_ (London, 1896); Oscar Cordel,
  _Neuester Leitfaden des Schachspiels_ (Berlin, 1896); and a vast
  number of other publications.

  Further, _The London Tournament Book_ (1883); _Twelve Tournament Books
  of the German Chess Association_ (Veit & Co., Leipzig); _The Hastings
  Tournament Book_ (London, 1896); _The Vienna_ _Tournament Book_, by
  Halprin and Marco (1900); _The Nuremberg Tournament Book_, by Dr
  Tarrasch; _The Book of the London Congress_, by L. Hoffer (Longman,
  1899); _The Paris Tournament Book_ (Paris, 1900), by Rosenthal, &c.

  The following are some of the best works in English on chess
  problems:--"J. B." of Bridport, _Chess Strategy_ (1865); F. Healey, _A
  Collection of 200 Chess Problems_ (1866); _English Chess Problems_,
  edited by James and W.T. Pierce (1876); H.J.C. Andrews, E.N.
  Frankenstein, B.G. Laws, and C. Planck, _The Chess Problem Text-Book_
  (1887); A.F. Mackenzie, _Chess: its Poetry and its Prose_ (Jamaica,
  1887); J.A. Miles, _Chess Stars_ (self-mates), (1888); James Rayner,
  _Chess Problems_ (1890); B.G. Laws, _The Two-Move Chess Problem_
  (1890); _The Chess Bouquet_, compiled by F.R. Gittins (1897); Mr and
  Mrs T.B. Rowland, _The Problem Art_ (2nd ed., 1898); E.B. Cook, T.
  Henery and C.A. Gilberg, _American Chess-Nuts_ (1868); Samuel Loyd,
  _Chess Strategy_ (1878); W.H. Lyons, _Chess-Nut Burrs and how to open
  them_ (1886); C.A. Gilberg, _Crumbs from the Chess Board_ (1890);
  _Canadian Chess Problems_, edited by C.F. Stubbs (1890); W. Pulitzer,
  _Chess Harmonies_ (1894); G.E. Carpenter (N. Preti of Paris), _200
  Chess Problems_ (1900).


FOOTNOTE:

  [1] The earliest known problem is ascribed to an Arabian caliph of
    the 9th century. The first known collection is in a manuscript (in
    the British Museum) of King Alphonso of Castile, dated 1250; it
    contains 103 problems. The collection of Nicolas of Lombardy, dated
    1300, comprises 192 problems.



CHEST (Gr. [Greek: kistê], Lat. _cista_, O. Eng. _cist, cest_,&c.), a
large box of wood or metal with a hinged lid. The term is also used of a
variety of kinds of receptacle; and in anatomy is transferred to the
portion of the body covered by the ribs and breastbone (see RESPIRATORY
SYSTEM). In the more ordinary meaning chests are, next to the chair and
the bed, the most ancient articles of domestic furniture. The chest was
the common receptacle for clothes and valuables, and was the direct
ancestor of the "chest of drawers," which was formed by enlarging the
chest and cutting up the front. It was also frequently used as a seat.
Indeed, in its origin it took in great measure the place of the chair,
which, although familiar enough to the ancients, had become a luxury in
the days when the chest was already an almost universal possession. The
chief use of chests was as wardrobes, but they were also often employed
for the storing of valuables. In the early middle ages the rich
possessed them in profusion, used them as portmanteaux, and carried them
about from castle to castle. These portable receptacles were often
covered with leather and emblazoned with heraldic designs. As houses
gradually became less sparsely furnished, chests and beds and other
movables were allowed to remain stationary, and the chest lost its
covered top, and took the shape in which we best know it--that of an
oblong box standing upon raised feet. As a rule it was made of oak, but
it was sometimes of chestnut or other hard wood.

There are, properly speaking, three types of chest--the domestic, the
ecclesiastical and the strong box or coffer. Old domestic chests still
exist in great number and some variety, but the proportion of those
earlier than the latter part of the Tudor period is very small; most of
them are Jacobean in date. Very frequently they were made to contain the
store of house-linen which a bride took to her husband upon her
marriage. In the 17th century Boulle and his imitators glorified the
marriage-coffer until it became a gorgeous casket, almost indeed a
sarcophagus, inlaid with ivory and ebony and precious woods, and
enriched with ormolu, supported upon a stand of equal magnificence. The
Italian marriage-chests (_cassone_) were also of a richness which was
never attempted in England. The main characteristics of English domestic
chests (which not infrequently are carved with names and dates) are
panelled fronts and ends, the feet being formed from prolongations of
the "stiles" or side posts. There were, however, exceptions, and a
certain number of 17th-century chests have separate feet, either
circular or shaped after the indications of a somewhat later style.
There is usually a strong architectural feeling about the chest, the
front being divided into panels, which are plain in the more ordinary
examples, and richly carved in the choicer ones. The plinth and frieze
are often of well-defined _guilloche_ work, or are carved with
arabesques or conventionalized flowers. Architectural detail, especially
the detail of wainscoting, has indeed been followed with considerable
fidelity, many of the earlier chests being carved in the linenfold
pattern, while the Jacobean examples are often mere reproductions of the
pilastered and recessed oaken mantelpieces of the period. Occasionally a
chest is seen which is inlaid with coloured woods, or with geometrical
parquetry. Perhaps the most elaborate type of English parquetry chest is
that named after the vanished Palace of Nonesuch. Such pieces are,
however, rarely met with. The entire front of this type is covered with
a representation of the palace in coloured woods. Another class of chest
is incised, sometimes rather roughly, but often with considerable
geometrical skill. The more ordinary variety has been of great value to
the forger of antique furniture, who has used its carved panels for
conversion into cupboards and other pieces, the history of which is not
easily unravelled by the amateur who collects old oak without knowing
much about it. Towards the end of the 17th century chests were often
made of walnut, or even of exotic woods such as cedar and cypress, and
were sometimes clamped with large and ornamental brass bands and hinges.
The chests of the 18th century were much larger than those of the
preceding period, and as often as not were furnished with two drawers at
the bottom--an arrangement but rarely seen in those of the 17th
century--while they were often fitted with a small internal box fixed
across one end for ready access to small articles. The chest was not
infrequently unpanelled and unornamented, and in the latter period of
its history this became the ruling type. It will not have been forgotten
that it was in an old oak chest that the real or mythical heroine of the
pathetic ballad of "The Mistletoe Bough" concealed herself, to her
undoing.

Ecclesiastical chests appear to have been used almost entirely as
receptacles for vestments and church plate, and those which survive are
still often employed for the preservation of parish documents. A
considerable variety of these interesting and often exceedingly
elaborate chests are still left in English churches. They are usually of
considerable size, and of a length disproportionate to their depth. This
no doubt was to facilitate the storage of vestments. Most of them are of
great antiquity. Many go back to the 14th century, and here and there
they are even earlier, as in the case of the coffer in Stoke d'Abernon
church, Surrey, which is unquestionably 13th-century work. One of the
most remarkable of these early examples is in Newport church, Essex. It
is one of the extremely rare painted coffers of the 13th century, the
front carved with an upper row of shields, from which the heraldic
painting has disappeared, and a lower row of roundels. Between is a belt
of open tracery, probably of pewter, and the inside of the lid is
decorated with oil paintings representing the Crucifixion, the Virgin
Mary, St Peter, St John and St Paul. The well-known "jewel chest" in St
Mary's, Oxford, is one of the earliest examples of 14th century work.
Many of these ecclesiastical chests are carved with architectural
motives--traceried windows most frequently, but occasionally with the
iinenfold pattern. There is a whole class of chests known as "tilting
coffers," carved with representations of tournaments or feats of arms,
and sometimes with a grotesque admixture of chivalric figures and
mythical monsters. Only five or six examples of this type are known
still to exist in England, and two of them are now in the Victoria and
Albert Museum. It is not certain that even these few are of English
origin--indeed, very many of the chests and coffers of the 16th and 17th
centuries are of foreign make. They were imported into England chiefly
from Flanders, and were subsequently carved by native artisans, as was
the case with other common pieces of furniture of those periods. The
_huche_ or "hutch" was a rough type of household chest.

The word "coffer" is properly applied to a chest which was intended for
the safe keeping of valuables. As a rule the coffer is much more massive
in construction than the domestic chest; it is clamped by iron bands,
sometimes contains secret receptacles opening with a concealed spring,
and is often furnished with an elaborate and complex lock, which
occupies the whole of the underside of the lid. Pieces of this type are
sometimes described as Spanish chests, from the belief that they were
taken from ships belonging to the Armada. It is impossible to say that
this may not sometimes have been the case, but these strong boxes are
frequently of English origin, although the mechanism of the locks may
have been due to the subtle skill of foreign locksmiths. A typical
example of the treasure chest is that which belonged to Sir Thomas
Bodley, and is preserved in the Bodleian library at Oxford. The locks of
this description of chest are of steel, and are sometimes richly
damascened. It was for being implicated in the breaking open and robbing
of just such a chest as this, to which the Collège de Navarre had
confided coin to the value of 500 ecus, that François Villon was hanged
on the gibbet of Montfaucon.



CHESTER, EARLS OF. The important palatine earldom of Chester was first
held by a certain Fleming named Gherbod (fl. 1070), and then by Hugh of
Avranches (d. 1101), a son of Richard, viscount of Avranches. Hugh, who
was probably one of William the Conqueror's companions, was made earl of
Chester in 1071; he had special privileges in his earldom, and he held
land in twenty counties. He was called _Le Gros_ on account of his great
bulk and _Lupus_ on account of his ferocity. However, he regarded St
Anselm as his friend, and he showed the customary liberality to
religious houses. His life was mainly spent in fighting the Welsh and in
Normandy, and he died on the 27th of July 1101. Hugh's only son Richard,
who was childless, was drowned in the White Ship in November 1120. Among
subsequent holders were Ralph, or Randulph, de Gernon (d. 1153), who
took a prominent part in the civil wars of the reign of Stephen,
fighting first on one side and then on the other; and his son Hugh de
Kevelioc (1147-1181), who shared in the rising against Henry II. in
1173. But perhaps the most celebrated of the early earls was Ralph,
Ranulf, or Randulph, de Blundevill (c. 1172-1232), who succeeded his
father Hugh de Kevelioc as earl in 1181, and was created earl of Lincoln
in 1217. Ranulf married Constance, widow of Henry II.'s son, Geoffrey of
Brittany, and is sometimes called duke of Brittany and earl of Richmond.
He fought in Wales, was on the side of John during his struggle with the
barons over Magna Carta, and was one of this king's executors; he also
fought for the young king Henry III. against the French invaders and
their allies. In 1218 he went on crusade to the Holy Land and took part
in the capture of Damietta; then returning to England he died at
Wallingford in October 1232. After speaking of Ranulf's unique position
in the kingdom, which "fitted him for the part of a leader of opposition
to royal or ministerial tyranny," Stubbs sums up his character in these
words: "On more than one occasion he refused his consent to taxation
which he deemed unjust; his jealousy of Hubert (de Burgh), although it
led him to join the foreign party in 1223, did not prevent him from more
than once interposing to prevent his overthrow. He was, moreover, almost
the last relic of the great feudal aristocracy of the Conquest."
Although twice married he left no children, and his immense possessions
passed to his four sisters. The earl's memory remained green for a long
time, and in the _Vision of Piers Plowman_ his name is linked with that
of Robin Hood. In November 1232 the earldom of Chester was granted to
his nephew John the Scot, earl of Huntingdon (c. 1207-1237), and in
1246, nine years after John had died childless, it was annexed to the
English crown "lest so fair a dominion should be divided among women."

In 1254 Prince Edward, afterwards King Edward I., was created earl of
Chester, and since this date the earldom has always been held by the
heirs apparent to the English crown with the single exception of Simon
de Montfort, earl of Leicester. Since 1399 the earls of Chester have
been also princes of Wales, although the act of Richard II. (1398),
which created Chester into a principality to be held by the king's
eldest son, was revoked by Henry IV.



CHESTER, an episcopal city and county of a city, municipal, county and
parliamentary borough, and the county town of Cheshire, England, 179 m.
N.W. of London. Pop. (1901) 38,309. It lies in a low plain on the Dee,
principally on the north (right) bank, 6 m. above the embouchure of the
river into its wide, shallow estuary. It is an important railway centre,
the principal lines serving it being the London & North-Western, Great
Western, Cheshire Lines and Great Central. The city is divided into four
principal blocks by the four principal streets--Northgate Street,
Eastgate Street, Bridge Street and Watergate Street, which radiate at
right angles from the Cross, and terminate in the four gates. These
four streets exhibit in what are called "the Rows" a characteristic
feature of the city. Their origin is a mystery, and has given rise to
much controversy. In Eastgate Street, Bridge Street and Watergate
Street, the Rows exist on each side of the street throughout the greater
part of its length, and may be described as continuous galleries open to
the street, over and under which the houses lining the streets project,
and which are formed as it were out of the front first-floor of the
houses, approached by flights of steps from the roadway. The Rows are
flagged or boarded under foot and ceiled above, thus forming a covered
way, standing in the same relation to the shops, which are at their
back, as the foot pavement does in other towns. In Northgate Street, on
the other hand, the Row on the west side is formed as it were out of the
ground floor of the houses, having cellars beneath, while on the east
side the Row is formed at the same elevation as in the other three
principal streets. In these streets are several examples of old timbered
houses and some good modern imitations of them,--all combining to give a
picturesque and individual character to the city. Among the most
interesting of the ancient houses are Derby House, bearing the date
1591, Bishop Lloyd's house, and God's Providence House in Watergate
Street, and the Bear and Billet in Lower Bridge Street; the three last
date from the 17th century. There is also a chamber with stone groined
roof of the 14th century in the basement of a house in Eastgate Street,
and another of a similar character in Watergate Street. A mortuary
chapel of the early part of the 13th century exists in the basement of a
house in Bridge Street.

Chester is the only city in England that still possesses its walls
perfect in their entire circuit of 2 m. The gateways have all been
rebuilt at various dates; the north and east gates on the site of the
Roman gates. The Grosvenor bridge, a single span of stone 200 ft. in
length, said to be the largest save one in Europe, carries the road to
Wrexham and Shrewsbury over the Dee on the south-west; while the old
bridge of seven arches is interesting on account of its antiquity and
picturesqueness. The castle, with the exception of "Caesar's Tower," and
a round tower with adjacent buildings, in the upper ward, was taken down
towards the end of the 18th century, and replaced by a gateway,
barracks, county hall, gaol and assize courts.

The cathedral church of Christ and the Virgin Mary, which stands towards
the north of the city within the walls, rose on the site of a church of
extreme antiquity. It appears that the dedication of this church was
altered, perhaps in the reign of Athelstan, from St. Peter and St Paul
to St Werburgh and St Oswald, St Werburgh being a niece of St Etheldreda
of Ely. In 1093 Hugh Lupus, earl of Chester, richly endowed the
foundation as a Benedictine monastery. The bishops of Mercia had
apparently a seat at Chester, but the city had ceased to be episcopal,
until in 1075 Peter, bishop of Lichfield, removed his seat thence to
Chester, having for his cathedral the collegiate church of St John. The
seat of the see, however, was quickly removed again to Coventry (1102),
but Cheshire continued subject to Lichfield until in 1541 Chester was
erected into a bishopric by Henry VIII., the church of the dissolved
abbey of St Werburgh becoming the cathedral. The diocese covers nearly
the whole of Cheshire, with very small portions of Lancashire and
Staffordshire. The cathedral does not rank among the most splendid
English churches, but possesses certain details of the highest interest,
and gains in beauty from the tones of its red sandstone walls and the
picturesque close in which it stands. It is cruciform with a central
tower 127 ft. high. The south transept is larger than the north. The
nave is short (145 ft.), being of six bays; the southern arcade is
Decorated, while the northern, which differs in detail, is of uncertain
date. The basement of the north-western tower--all that remains of it,
now used as a baptistery--is Norman, and formed part of Hugh Lupus'
church; and the fabric of the north wall is also of this period. The
north transept also retains Norman work, and its size shows the original
plan, as the existence of the conventual buildings to the north probably
rendered its extension undesirable. The south transept has aisles, with
Decorated and Perpendicular windows. The fine organ stands on a screen
across the north transept; but some of its pipes are upon the choir
screen, both screens being the work of Sir Gilbert Scott. The style of
the choir is transitional from Early English to Decorated, and its
length is 125 ft. It is a fine example, and its beauty is enhanced by
the magnificent series of ancient carved wooden stalls unsurpassed in
England. The Lady Chapel, east of the choir, is of rich Early English
workmanship. Of the conventual buildings the cloisters are
Perpendicular. The chapter-house, entered by a beautiful vestibule from
the east cloister, and lined with cases containing the chapter library,
is Early English (c. 1240). The refectory, adjoining the north cloister,
is of the same period, with Perpendicular insertions; it has been
curtailed in size, but retains its beautiful Early English lector's
pulpit. An early Norman chamber, with massive pillars and vaulting,
adjoins the west cloister, and may be the substructure of the abbot's
house. The abbey gateway is of the 14th century.

Within the walls there are several churches of ancient foundation; thus
St Peter's is said to occupy the site of a church erected by Æthelflæd,
queen of Mercia, and St Mary's dates from the 12th century. None,
however, is of any special interest; but the church of St John, outside
the walls, which as already stated became the cathedral in 1075, is a
massive early Norman structure, with later additions, and, especially as
regards the exterior, considerably restored in modern times. Its fine
tower fell in 1881. It was a collegiate church until 1547, and there are
some remains of the adjoining buildings. Among numerous modern churches
there may be mentioned St Mary's without the walls, built in 1887 by the
duke of Westminster, of red sandstone, with a fine spire' and peal of
bells.

Among the chief secular buildings, the town hall replaced in 1869 the
old exchange, which had been burnt down in 1862. The Grosvenor Museum
and School of Art, the foundation of which was suggested by Charles
Kingsley the novelist, when canon of Chester cathedral, contains many
local antiquities, along with a fine collection of the fauna of Cheshire
and the neighbourhood. The King's school was founded by Henry VIII.
(1541), who provided that twenty-four poor scholars should be taught
free of cost. It was reorganized as a public school in 1873, and
possesses twelve king's scholarships tenable in the school, and close
scholarships tenable at the universities. Among other schools may be
mentioned the blue-coat school (1700), the Queen's school for girls
(1878), the girls' school attached to the Roman Catholic convent, and
the diocesan training college for schoolmasters. For recreation
provision is made by the New Grosvenor Park, presented to the city in
1867 by the marquess of Westminster; Handbridge Park, opened in 1892;
and the Roodee, a level tract by the river at the base of the city wall,
appropriated as a race-course. An annual race-meeting is held in May and
attendedby thousands. The chief event is the race for the Chester Cup,
which dates from 1540, when a silver bell was given as the prize by the
Saddlers' Company. Pleasure vessels ply on the Dee in summer, and an
annual regatta is held, at which all the principal northern rowing-clubs
are generally represented. The town gains in prosperity from its large
number of visitors. The principal industries are carried on without the
walls, where there are lead, shot and paint works, leather and tobacco
factories, and iron foundries. The trade gilds number twenty-four. There
is a considerable amount of shipping on the Dee, the navigation having
been much improved in modern times. The parliamentary borough returns
one member. The municipal council consists of a mayor, 10 aldermen and
30 councillors. Area, 2862 acres.

_History._--Setting aside the numerous legends with regard to the
existence of a British city on the site now occupied by Chester, the
earliest authentic information relating to its history is furnished by
the works of Ptolemy and Antoninus. As the Roman station of Deva it was
probably founded about A.D. 48 by Ostorius Scapula, and from its
advantageous position, both as the key to communication with Ireland and
as a bulwark against the hostile tribes of the north, it became a
military and commercial centre of considerable importance. In A.D. 78-79
it was the winter-quarters of Agricola, and later became illustrious as
the permanent headquarters of Legio XX. Valeria Victrix. Many
inscriptions and remains of the Roman military occupation have been
found, and the north and east walls stand in great part on Roman
foundations. The Saxon form of the name was Leganceaster. About 614 the
city was captured and destroyed by Æthelfrith, and henceforth lay in
ruins until Æthelflæd in 907 rebuilt the walls, restored the monastery
of St Werburgh, and made the city "nigh two such as it was before." In
the reign of Æthelstan a mint was set up at Chester, and in 973 it was
the scene of Edgar's truimph when, it is said, he was rowed on the Dee
by six subject kings. Chester opposed a determined resistance to the
Conqueror, and did not finally surrender until 1070. On the erection of
Cheshire to a county palatine after the Conquest, Chester became the
seat of government of the palatine earls. The Domesday account of the
city includes a description of the Saxon laws under which it had been
governed in the time of Edward the Confessor. All the land, except the
bishop's borough, was held of the earl, and assessed at fifty hides.
There were seven mint-masters and twelve magistrates, and the city paid
a fee-farm rent of £45. It had been much devastated since the time of
Edward the Confessor, and the number of houses reduced by 205.

The earliest extant charter, granted by Henry II. in 1160, empowered the
burgesses to trade with Durham as freely as they had done in the reign
of Henry I. From this date a large collection of charters enumerates
privileges granted by successive earls and later sovereigns. One from
Ralph or Ranulf de Blundevill, granted between 1190 and 1211, confirms
to the citizens a gild merchant and all liberties and free customs, and
three from John protect their privilege of trading with Ireland. Edward
I. empowered the citizens to elect coroners and to hold courts of
justice, and granted them the fee-farm of the city at a yearly rent of
£100. In the 14th century Chester began to lose its standing as a port
through the gradual silting up of the estuary of the Dee, and the city
was further impoverished by the inroads of the Welsh and by the
necessity of rebuilding the Dee bridge, which had been swept away by an
unusually high tide. In consideration of these misfortunes Richard II.
remitted part of the fee-farm. Continued misfortunes led to a further
reduction of the farm to £50 for a term of fifty years by Henry VI., who
also made a grant for the completion of a new Dee bridge. Henry VII.
reduced the fee-farm to £20, and in 1506 granted to the citizens what is
known as "the Great Charter." This charter constituted the city a county
by itself, and incorporated the governing body under the style of a
mayor, twenty-four aldermen and forty common councilman; it also
instituted two sheriffs, two coroners and a recorder, and the mayor, the
ex-mayors and the recorder were appointed justices of the peace. This
charter was confirmed by James I. and Charles II. A charter of George
III. in 1804 instituted the office of deputy-mayor. The charter of Hugh
Lupus to the abbey of St Werburgh includes a grant of the tolls of the
fair at the feast of St Werburgh for three days, and a subsequent
charter from Ranulf de Blundevill (12th century) licensed the abbot and
monks to hold their fairs and markets before the abbey gates. A charter
of John the Scot, earl of Chester, mentions fairs at the feasts of the
Nativity of St John Baptist and St Michael. For many centuries the
rights claimed by the abbot in connexion with the fairs gave rise to
constant friction with the civic authorities, which lasted until, in the
reign of Henry VIII., it was decreed that the right of holding fairs was
vested exclusively in the citizens. Charles II. in 1685 granted a
cattle-fair to be held on the first Thursday in February.

In 1553 Chester first returned two members to parliament, having
hitherto been represented solely in the parliament of the palatinate. By
the Redistribution Act of 1885 the representation was reduced to one
member. The trades of tanners, skinners and glove-makers existed at the
time of the Conquest, and the importation of marten skins is mentioned
in Domesday. In the 14th century the woollen trade was considerable, and
in 1674 weavers and wool-combers were introduced into Chester from
Norwich. The restoration of the channel of the Dee opened up a
flourishing trade in Irish linen, which in 1786 was at its height, but
from that date gradually diminished.

  See _Victoria County History, Cheshire_; R. H. Morris, _Chester in the
  Plantagenet and Tudor Reigns_ (Chester, 1894); Joseph Hemingway,
  _History of the City of Chester_ (2 vols., Chester, 1831).



CHESTER, a city of Delaware county, Pennsylvania, U.S.A., on the
Delaware river, about 13 m. S.W. of Philadelphia. Pop. (1800) 20,226;
(1900) 33,988, of whom 5074 were foreign-born and 44O3 were negroes; (U.
S. census, 1910) 38,537. It is served by the Baltimore & Ohio and the
Philadelphia & Reading railways, by the Philadelphia, Baltimore &
Washington division of the Pennsylvania system, and by steamboat lines.
Chester has several interesting buildings dating from early in the 18th
century--among them the city hall (1724), one of the oldest public
buildings in the United States, and the house (1683) occupied for a time
by William Penn. It is the seat of the Pennsylvania Military College
(1862); and on the border of Chester, in the borough of Upland (pop. in
1900, 2131), is the Crozer Theological Seminary (Baptist), which was
incorporated in 1867, opened in 1868, and named after John P. Crozer
(1793-1866), by whose family it was founded. Chester has a large
shipbuilding industry, and manufactories of cotton and worsted goods,
iron and steel, the steel-casting industry being especially important,
and large quantities of wrought iron and steel pipes being manufactured.
Dye-stuffs and leather also are manufactured. The value of the city's
factory products in 1905 was $16,644,842. Chester is the oldest town in
Pennsylvania. It was settled by the Swedes about 1645, was called Upland
and was the seat of the Swedish courts until 1682, when William Penn,
soon after his landing at a spot in the town now marked by a memorial
stone, gave it its present name. The first provincial assembly was
convened here in December of the same year. After the battle of
Brandywine in the War of Independence, Washington retreated to Chester,
and in the "Washington House," still standing, wrote his account of the
battle. Soon afterwards Chester was occupied by the British. In 1701 it
was incorporated as a borough; in 1795 and again in 1850 it received a
new borough charter; and in 1866 it was chartered as a city. For a long
time it was chiefly a small fishing settlement, its population as late
as 1820 being only 657; but after the introduction of large
manufacturing interests in 1850, when its population was only 1667, its
growth was rapid.

  See H. G. Ashmead, _Historical Sketch of Chester_ (Chester, 1883).



CHESTERFIELD, PHILIP DORMER STANHOPE, 4TH EARL OF (1694-1773), son of
Philip Stanhope, third earl (1673-1726), and Elizabeth Savile, daughter
of George Savile, marquess of Halifax, was born in London on the 22nd of
September 1694; Philip, the first earl (1584-1656), son of Sir John
Stanhope of Shelford, was a royalist who in 1616 was created Baron
Stanhope of Shelford, and in 1628 earl of Chesterfield; and his grandson
the 2nd earl (1633-1714) was grandfather of the 4th earl. Deprived at an
early age of his mother, the care of the boy devolved upon his
grandmother, the marchioness of Halifax, a lady of culture and
connexion, whose house was frequented by the most distinguished Whigs of
the epoch. He soon began to prove himself possessed of that systematic
spirit of conduct and effort which appeared so much in his life and
character. His education, begun under a private tutor, was continued
(1712) at Trinity Hall, Cambridge; here he remained little more than a
year and seems to have read hard, and to have acquired a considerable
knowledge of ancient and modern languages. The great orators of all
times were a special object of study with him, and he describes his
boyish pedantry pleasantly enough, but by no means without a touch of
self-satisfaction in the memory. His university training was
supplemented (1714) by a continental tour, untrammelled by a governor;
at the Hague his ambition for the applause awarded to adventure made a
gamester of him, and at Paris he began, from the same motive, that
worship of the conventional Venus, the serious inculcation of which has
earned for him the largest and most unenviable part of his reputation.

The death of Anne and the accession of George I. opened up a career for
him and brought him back to England. His relative James Stanhope
(afterwards first Earl Stanhope), the king's favourite minister,
procured for him the place of gentleman of the bedchamber to the prince
of Wales. In 1715 he entered the House of Commons as Lord Stanhope of
Shelford and member for St Germans, and when the impeachment of James,
duke of Ormonde, came before the House, he used the occasion (5th of
August 1715) to put to proof his old rhetorical studies. His maiden
speech was youthfully fluent and dogmatic; but on its conclusion the
orator was reminded with many compliments, by an honourable member, that
he wanted six weeks of his majority, and consequently that he was
amenable to a fine of £500 for speaking in the House. Lord Stanhope
quitted the Commons with a low bow and started for the continent. From
Paris he rendered the government important service by gathering and
transmitting information respecting the Jacobite plot; and in 1716 he
returned to England, resumed his seat, and took frequent part in the
debates. In that year came the quarrel between the king and the heir
apparent. Stanhope, whose politic instinct obliged him to worship the
rising rather than the setting sun, remained faithful to the prince,
though he was too cautious to break entirely with the king's party. He
was on friendly terms with the prince's mistress, Henrietta Howard,
afterwards countess of Suffolk. He maintained a correspondence with this
lady which won for him the hatred of the princess of Wales (afterwards
Queen Caroline). In 1723 a vote for the government got him the place of
captain of the Gentlemen Pensioners. In January 1725, on the revival of
the Bath, the red riband was offered to him, but was declined.

In 1726 his father died, and Lord Stanhope became earl of Chesterfield.
He took his seat in the Upper House, and his oratory, never effective in
the Commons by reason of its want of force and excess of finish, at once
became a power. In 1728 Chesterfield was sent to the Hague as
ambassador. In this place his tact and temper, his dexterity and
discrimination, enabled him to do good service, and he was rewarded with
Walpole's friendship, a Garter and the place of lord high steward. In
1732 there was born to him, by a certain Mlle du Bouchet, the son,
Philip Stanhope, for whose advice and instruction were afterwards
written the famous _Letters_. He negotiated the second treaty of Vienna
in 1731, and in the next year, being somewhat broken in health and
fortune, he resigned his embassy and returned to England.

A few months' rest enabled him to resume his seat in the Lords, of which
he was one of the acknowledged leaders. He supported the ministry, but
his allegiance was not the blind fealty Walpole exacted of his
followers. The Excise Bill, the great premier's favourite measure, was
vehemently opposed by him in the Lords, and by his three brothers in the
Commons. Walpole bent before the storm and abandoned the measure; but
Chesterfield was summarily dismissed from his stewardship. For the next
two years he led the opposition in the Upper House, leaving no stone
unturned to effect Walpole's downfall. In 1741 he signed the protest for
Walpole's dismissal and went abroad on account of his health. He visited
Voltaire at Brussels and spent some time in Paris, where he associated
with the younger Crebillon, Fontenelle and Montesquieu. In 1742 Walpole
fell, and Carteret was his real, though not his nominal successor.
Although Walpole's administration had been overthrown largely by
Chesterfield's efforts the new ministry did not count Chesterfield
either in its ranks or among its supporters. He remained in opposition,
distinguishing himself by the courtly bitterness of his attacks on
George II., who learned to hate him violently. In 1743 a new journal,
_Old England; or, the Constitutional Journal_ appeared. For this paper
Chesterfield wrote under the name of "Jeffrey Broadbottom." A number of
pamphlets, in some of which Chesterfield had the help of Edmund Waller,
followed. His energetic campaign against George II. and his government
won the gratitude of the dowager duchess of Marlborough, who left him
£20,000 as a mark of her appreciation. In 1744 the king was compelled to
abandon Carteret, and the coalition or "Broad Bottom" party, led by
Chesterfield and Pitt, came into office. In the troublous state of
European politics the earl's conduct and experience were more useful
abroad than at home, and he was sent to the Hague as ambassador a second
time. The object of his mission was to persuade the Dutch to join in the
War of the Austrian Succession and to arrange the details of their
assistance. The success of his mission was complete; and on his return a
few weeks afterwards he received the lord-lieutenancy of Ireland--a
place he had long coveted.

Short as it was, Chesterfield's Irish administration was of great
service to his country, and is unquestionably that part of his political
life which does him most honour. To have conceived and carried out a
policy which, with certain reservations, Burke himself might have
originated and owned, is indeed no small title to regard. The earl
showed himself finely capable in practice as in theory, vigorous and
tolerant, a man to be feared and a leader to be followed; he took the
government entirely into his own hands, repressed the jobbery
traditional to the office, established schools and manufactures, and at
once conciliated and kept in check the Orange and Roman Catholic
factions. In 1746, however, he had to exchange the lord-lieutenancy for
the place of secretary of state. With a curious respect for those
theories his familiarity with the secret social history of France had
caused him to entertain, he hoped and attempted to retain a hold over
the king through the influence of Lady Yarmouth, though the futility of
such means had already been demonstrated to him by his relations with
Queen Caroline's "_ma bonne Howard_." The influence of Newcastle and
Sandwich, however, was too strong for him; he was thwarted and
over-reached; and in 1748 he resigned the seals, and returned to cards
and his books with the admirable composure which was one of his most
striking characteristics. He declined any knowledge of the _Apology for
a late Resignation, in a Letter from an English Gentleman to his Friend
at The Hague_, which ran through four editions in 1748, but there is
little doubt that he was, at least in part, the author.

The dukedom offered him by George II., whose ill-will his fine tact had
overcome, was refused. He continued for some years to attend the Upper
House, and to take part in its proceedings. In 1751, seconded by Lord
Macclesfield, president of the Royal Society, and Bradley, the eminent
mathematician, he distinguished himself greatly in the debates on the
calendar, and succeeded in making the new style a fact. Deafness,
however, was gradually affecting him, and he withdrew little by little
from society and the practice of politics. In 1755 occurred the famous
dispute with Johnson over the dedication to the _English Dictionary_. In
1747 Johnson sent Chesterfield, who was then secretary of state, a
prospectus of his _Dictionary_, which was acknowledged by a subscription
of £10. Chesterfield apparently took no further interest in the
enterprise, and the book was about to appear, when he wrote two papers
in the _World_ in praise of it. It was said that Johnson was kept
waiting in the anteroom when he called while Cibber was admitted. In any
case the doctor had expected more help from a professed patron of
literature, and wrote the earl the famous letter in defence of men of
letters. Chesterfield's "respectable Hottentot," now identified with
George, Lord Lyttelton, was long supposed, though on slender grounds, to
be a portrait of Johnson. During the twenty years of life that followed
this episode, Chesterfield wrote and read a great deal, but went little
into society.

In 1768 died Philip Stanhope, the child of so many hopes. The constant
care bestowed by his father on his education resulted in an honourable
but not particularly distinguished career for young Stanhope. His death
was an overwhelming grief to Chesterfield, and the discovery that he had
long been married to a lady of humble origin must have been galling in
the extreme to his father after his careful instruction in worldly
wisdom. Chesterfield, who had no children by his wife, Melusina von
Schulemberg, illegitimate daughter of George I., whom he married in
1733, adopted his godson, a distant cousin, named Philip Stanhope
(1755-1815), as heir to the title and estates. His famous jest (which
even Johnson allowed to have merit)--"Tyrawley and I have been dead
these two years, but we don't choose to have it known"--is the best
description possible of his humour and condition during the latter part
of this period of decline. To the deafness was added blindness, but his
memory and his fine manners only left him with life; his last words
("Give Dayrolles a chair") prove that he had neither forgotten his
friend nor the way to receive him. He died on the 24th of March 1773.

Chesterfield was selfish, calculating and contemptuous; he was not
naturally generous, and he practised dissimulation till it became part
of his nature. In spite of his brilliant talents and of the admirable
training he received, his life, on the whole, cannot be pronounced a
success. His anxiety and the pains he took to become an orator have been
already noticed, and Horace Walpole, who had heard all the great
orators, preferred a speech of Chesterfield's to any other; yet the
earl's eloquence is not to be compared with that of Pitt. Samuel
Johnson, who was not perhaps the best judge in the world, pronounced his
manners to have been "exquisitely elegant"; yet as a courtier he was
utterly worsted by Robert Walpole, whose manners were anything but
refined, and even by Newcastle. He desired to be known as a protector of
letters and literary men; and his want of heart or head over the
_Dictionary_ dedication, though explained and excused by Croker, none
the less inspired the famous change in a famous line--"Toil, envy, want,
_the patron_, and the jail." His published writings have had with
posterity a very indifferent success; his literary reputation rests on a
volume of letters never designed to appear in print. The son for whom he
worked so hard and thought so deeply failed especially where his father
had most desired he should succeed.

As a politician and statesman, Chesterfield's fame rests on his short
but brilliant administration of Ireland. As an author he was a clever
essayist and epigrammatist. But he stands or falls by the _Letters to
his Son_, first published by Stanhope's widow in 1774, and the _Letters
to his Godson_ (1890). The _Letters_ are brilliantly written--full of
elegant wisdom, of keen wit, of admirable portrait-painting, of
exquisite observation and deduction. Against the charge of an undue
insistence on the external graces of manner Chesterfield has been
adequately defended by Lord Stanhope (_History_, iii. 34). Against the
often iterated accusation of immorality, it should be remembered that
the _Letters_ reflected the morality of the age, and that their author
only systematized and reduced to writing the principles of conduct by
which, deliberately or unconsciously, the best and the worst of his
contemporaries were governed.

The earldom of Chesterfield passed at his death to his godson, already
mentioned, as 5th earl, and so to the latter's son and grandson. On the
death of the latter unmarried in 1871, it passed in succession to two
collateral heirs, the 8th and 9th earls, and so in 1887 to the latter's
son as 10th earl.

  See Chesterfield's _Miscellaneous Works_ (London, 1777, 2 vols. 4to);
  _Letters to his Son, &c._, edited by Lord Mahon (London, 1845-1853, 5
  vols.); and _Letters to his Godson_ (1890) (edited by the earl of
  Carnarvon). There are also editions of the first series of letters by
  J. Bradshaw (3 vols., 1892) and Mr C. Strachey (2 vols., 1901). In
  1893 a biography, including numerous letters first published from the
  Newcastle Papers, was issued by Mr W. Ernst; and in 1907 appeared an
  elaborate _Life_ by W.H. Craig. (A.D.)



CHESTERFIELD, a market town and municipal borough in the Chesterfield
parliamentary division of Derbyshire, England, 24 m. N. by E. of Derby,
on the Midland and the Great Central railways. Pop. (1891) 22,009;
(1901) 27,185. It lies at the junction of two streams, the Rother and
Hipper, in a populous industrial district. It is irregularly built, with
narrow streets, but has a spacious market-place. The church of St Mary
and All Saints is a large and beautiful cruciform building principally
of the Decorated period. Its central tower carries a remarkable twisted
spire of wood covered with lead, 230 ft. high; the distortion has
evidently taken place through the use of unseasoned timber and
consequent warping of the woodwork. The church, which contains numerous
interesting monuments, possesses also the unusual feature of an apsidal
Decorated chapel. There is an example of flamboyant tracery in one of
the windows. Among public buildings, the Stephenson memorial hall
(1879), containing a free library, art and science class-rooms, a
theatre and the rooms of the Chesterfield Institute, commemorates George
Stephenson, the engineer, who resided at Tapton House, close to
Chesterfield, in his later life; he died here in 1848, and was buried in
Trinity church. Chesterfield grammar school was founded in 1574. The
industries of the town include manufactures of cotton, silk,
earthenware, machinery and tobacco, with brass and iron founding; while
slate and stone are quarried, and there are coal, iron and lead mines in
the neighbourhood. The town is governed by a mayor, 6 aldermen and 18
councillors. Area, 1216 acres. In the immediate neighbourhood of
Chesterfield on the west is the urban district of Brampton and Walton
(pop. 2698), to the south-east is Hasland (7427), and to the north-east
Brimington (4569).

In spite of the Roman origin suggested by its name, so few remains have
been found here that it is doubtful whether Chesterfield was a Roman
station. Chesterfield (_Cestrefeld_) owes its present name to the
Saxons. It is mentioned in Domesday only as a bailiwick of Newbold
belonging to the king, and granted to William Peverell. In 1204 John
gave the manor to William Bruere and granted to the town all the
privileges of a free borough which were enjoyed by Nottingham and Derby;
but before this it seems to have had prescriptive borough rights. Later
charters were granted by various sovereigns, and it was incorporated by
Elizabeth in 1598 under the style of a mayor, 6 brethren and 12 capital
burgesses. This charter was confirmed by Charles II. (1662), and the
town was so governed till the Municipal Act 1835 appointed a mayor, 3
aldermen and 12 councillors. In 1204 John granted two weekly markets, on
Tuesday and Saturday, and an annual fair of eight days at the feast of
the Exaltation of the Holy Cross (Sept. 14). This fair, which is still
held, and another on Palm Tuesday, are mentioned in the _Quo
Warranto_ roll of 1330. The Tuesday market has long been discontinued.
That Chesterfield was early a thriving centre is shown by the charter of
John Lord Wake, lord of the manor, granting a gild merchant to the town.
In 1266 the town was the scene of a battle between the royal forces and
the barons, when Robert de Ferrers, earl of Derby, was taken prisoner.
In 1586 there was a terrible visitation of the plague; and the
parliamentarian forces were overthrown here in the Civil War. With the
development of cotton and silk industries the town has increased
enormously, and is now second in importance only to Derby among the
towns of the county. There is no record that it ever returned
representatives to parliament.

  See Stephen Glover, _History and Gazetteer of the County of Derby_
  (Derby, 1831-1833); J. Pym Yeatman, _Records of the Borough of
  Chesterfield_ (Chesterfield and Sheffield, 1884); Thomas Ford,
  _History of Chesterfield_ (London, 1839).



CHESTER-LE-STREET, a town in the Chester-le-Street parliamentary
division of Durham, England, near the river Wear, 6 m. N. of the city of
Durham on the North-Eastern railway. Pop. (1901) 11,753. The parish
church of St Mary and St Cuthbert is an interesting building, formerly
collegiate, with a tower 156 ft. high, and a remarkable series of
monumental tombs of the Lumley family, collected here from Durham
cathedral and various ruined monasteries, and in some cases remade.
About 1 m. along the river is Lumley Castle, the seat of the earl of
Scarborough, and about 2 m. north lies Lambton Castle, the residence of
the earl of Durham, built in 1797 on the site of the old House of
Harraton. Collieries and iron-works employ the industrial population.
Chester-le-Street is a place of considerable antiquity. It lies on a
branch of the Roman north road, on which it was a station, but the name
is not known. Under the name of _Cunecastre_ it was made the seat of a
bishop in 882, and continued to be the head of the diocese till the
Danish invasion of 995. During that time the church was the repository
of the shrine of St Cuthbert, which was then removed to Durham.



CHESTERTON, GILBERT KEITH (1874-   ), English journalist and author, who
came of a family of estate-agents, was born in London on the 29th of May
1874. He was educated at St Paul's school, which he left in 1891 with
the idea of studying art. But his natural bent was literary, and he
devoted himself mainly to cultivating that means of expression, both in
prose and verse; he did occasional reviewing, and had some experience in
a publisher's office. In 1900, having already produced a volume of
clever poems, _The Wild Knight_, he definitely took to journalism as a
career, and became a regular contributor of signed articles to the
Liberal journals, the _Speaker_ and _Daily News_. He established himself
from the first as a writer with a distinct personality, combative to a
swashbuckling degree, unconventional and dogmatic; and the republication
of much of his work in a series of volumes (e.g. _Twelve Types_,
_Heretics_, _Orthodoxy_), characterized by much acuteness of criticism,
a pungent style, and the capacity of laying down the law with unflagging
impetuosity and humour, enhanced his reputation. His powers as a writer
are best shown in his studies of Browning (in the "English Men of
Letters" series) and of Dickens; but these were only rather more
ambitious essays among a medley of characteristic utterances, ranging
from fiction (including _The Napoleon of Notting-hill_) to fugitive
verse, and from artistic criticism to discussions of ethics and
religion. The interest excited by his work and views was indicated and
analysed in an anonymous volume (_G.K. Chesterton: a Criticism_)
published in 1908.



CHESTERTON, an urban district in the Chesterton parliamentary division
of Cambridgeshire, England, 1½ m. N. from Cambridge station, on the
north bank of the Cam. Pop. (1901) 9591. The church of St Andrew is
Decorated and Perpendicular, retaining ancient woodwork and remains of
fresco painting. Along the river are several boat-houses erected by the
Cambridge University Boat Club. Boat-building and tile manufacture are
local industries.



CHESTNUT (_nux Castanea_), the common name given to two sorts of trees
and their fruit, (1) the so-called "horse-chestnut," and (2) the sweet
or "Spanish" chestnut.

(1) The common horse-chestnut, _Aesculus Hippocastanum_ (Ger.
_Rosskastanie_; Fr. _marronnier d'Inde_), has been stated to be a native
of Tibet, and to have been brought thence to England in 1550; it is now,
however, thought to be indigenous in the mountains of northern Greece,
where it occurs wild at 3000 to 4000 ft. above sea-level. Matthiolus,
who attributes the origin of the name of the tree to the use of the nuts
by the inhabitants of Constantinople for the relief of short-windedness
and cough in horses, remarks that no ancient writer appears to have made
mention of the horse-chestnut. Clusius (_Rariorum plantarum hist._ i. p.
8, 1601) describes it as a vegetable curiosity, of which in 1588 he had
left in Vienna a living specimen, but of which he had not yet seen
either the flowers or recent fruit. The dry fruit, he says, had
frequently been brought from Constantinople into Europe.

The tree grows rapidly; it flourishes best in a sandy, somewhat moist
loam, and attains a height of 50 to 60 or more ft., assuming a pyramidal
outline. Its boughs are strong and spreading. The buds, conspicuous for
their size, are protected by a coat of a glutinous substance, which is
impervious to water; in spring this melts, and the bud-scales are then
cast off. The leaves are composed of seven radiating leaflets
(long-wedge-shaped); when young they are downy and drooping. From the
early date of its leafing year by year, a horse-chestnut in the
Tuileries is known as the "Marronnier du 20 mars." The flowers of the
horse-chestnut, which are white dashed with red and yellow, appear in
May, and sometimes, but quite exceptionally, again in autumn; they form
a handsome erect panicle, but comparatively few of them afford mature