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Title: Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 9 - "Dyer" to "Echidna"
Author: Various
Language: English
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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 8, Slice 9 - "Dyer" to "Echidna"" ***

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Transcriber's notes:

(1) Numbers following letters (without space) like C2 were originally
      printed in subscript. Letter subscripts are preceded by an
      underscore, like C_n.

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

(3) Side-notes were relocated to function as titles of their respective
      paragraphs.

(4) Macrons and breves above letters and dots below letters were not
      inserted.

(5) dP stands for the partial-derivative symbol, or curled 'd'.

(6) [oo] stands for the infinity symbol, and [int] for the integral
      symbol.

(7) Letters followed with a grave accent "`" have originally dots above.

(8) The following typographical errors have been corrected:

    ARTICLE DYER, JOHN: "His poems were collected by Dodsley in 1770,
      and by Mr Edward Thomas in 1903 for the Welsh Library, vol. iv."
      'poems' amended from 'peoms'.

    ARTICLE EAR: "The membranous semicircular canals are very much
      smaller in section than the bony; in the ampulla of each is a
      ridge..." 'the' amended from 'tbe'.

    ARTICLE EARTH, FIGURE OF THE: "O. Callandreau, 'Mémoire sur la
      théorie de la figure des planètes,' Ann. obs. de Paris (1889);..."
      'Callandreau' amended from 'Callendreau'.

    ARTICLE EATON, THEOPHILUS: "In October 1639 a form of government
      was adopted, based on the Mosaic Law, and Eaton was elected
      governor..." 'Mosaic' amended from 'Mosiac'.

    ARTICLE ECCLESIASTES: "A particular instance is mentioned (ix.
      13-15) of a beleaguered city saved by a wise man; but the man
      happened to be poor, and no one remembered him." 'beleaguered'
      amended from 'beleagured'.

    ARTICLE ECCLESIASTES: "Such assertions as those of ii. 26 (God
      gives joy to him who pleases him, and makes the sinner toil to lay
      up for the latter),..." 'and' amended from 'amd'.

    ARTICLE ECCLESIASTES: "This disagreement comes largely from the
      attempts made to find definitely expressed Greek philosophical
      dogmas in the book; such formulas it has not, but the general air
      of Greek reflection seems unmistakable. The scepticism of Koheleth
      differs from that of Job in quality and scope..." 'the' originally
      repeated twice.

    ARTICLE ECCLESIASTICAL JURISDICTION: "In the first case, they may
      be punished by the ordinary of the place, acting as delegate of the
      pope without special appointment (Conc. Trid. Sess. vi. c. 3)."
      'special' amended from 'speical'.



          ENCYCLOPAEDIA BRITANNICA

  A DICTIONARY OF ARTS, SCIENCES, LITERATURE
           AND GENERAL INFORMATION

              ELEVENTH EDITION


           VOLUME VIII, SLICE IX

              Dyer to Echidna



ARTICLES IN THIS SLICE:


  DYER, SIR EDWARD              EAST LIVERPOOL
  DYER, JOHN                    EAST LONDON
  DYER, THOMAS HENRY            EASTON
  DYMOKE                        EAST ORANGE
  DYNAMICS                      EASTPORT
  DYNAMITE                      EAST PROVIDENCE
  DYNAMO                        EAST PRUSSIA
  DYNAMOMETER                   EASTWICK, EDWARD BACKHOUSE
  DYNASTY                       EATON, DORMAN BRIDGMAN
  DYSART                        EATON, MARGARET O'NEILL
  DYSENTERY                     EATON, THEOPHILUS
  DYSPEPSIA                     EATON, WILLIAM
  DYSTELEOLOGY                  EATON, WYATT
  DZUNGARIA                     EAU CLAIRE
  E                             EAU DE COLOGNE
  EA                            EAUX-BONNES
  EABANI                        EAVES
  EACHARD, JOHN                 EAVESDRIP
  EADBALD                       EBBW VALE
  EADIE, JOHN                   EBEL, HERMANN WILHELM
  EADMER                        EBEL, JOHANN GOTTFRIED
  EADS, JAMES BUCHANAN          EBER, PAUL
  EAGLE                         EBERBACH (town of Germany)
  EAGLEHAWK                     EBERBACH (monastery of Germany)
  EAGRE                         EBERHARD
  EAKINS, THOMAS                EBERHARD, CHRISTIAN AUGUST GOTTLOB
  EALING                        EBERHARD, JOHANN AUGUSTUS
  EAR                           EBERLIN, JOHANN ERNST
  EARL                          EBERS, GEORG MORITZ
  EARLE, JOHN                   EBERSWALDE
  EARLE, RALPH                  EBERT, FRIEDRICH ADOLF
  EARL MARSHAL                  EBINGEN
  EARLOM, RICHARD               EBIONITES
  EARLSTON                      EBNER-ESCHENBACH, MARIE
  EARLY, JUBAL ANDERSON         EBOLI
  EARLY ENGLISH PERIOD          EBONY
  EARN                          EBRARD, JOHANNES HEINRICH AUGUST
  EARNEST                       EBRO
  EAR-RING                      EBROÏN
  EARTH                         EBURACUM
  EARTH, FIGURE OF THE          EÇA DE QUEIROZ, JOSÉ MARIA
  EARTH CURRENTS                ÉCARTÉ
  EARTH-NUT                     ECBATANA
  EARTH PILLAR                  ECCARD, JOHANN
  EARTHQUAKE                    ECCELINO DA ROMANO
  EARTH-STAR                    ECCENTRIC
  EARTHWORM                     ECCHELLENSIS, ABRAHAM
  EARWIG                        ECCLES
  EASEMENT                      ECCLESFIELD
  EAST, ALFRED                  ECCLESHALL
  EAST ANGLIA                   ECCLESIA
  EASTBOURNE                    ECCLESIASTES
  EAST CHICAGO                  ECCLESIASTICAL COMMISSIONERS
  EASTER                        ECCLESIASTICAL JURISDICTION
  EASTER ISLAND                 ECCLESIASTICAL LAW
  EASTERN BENGAL AND ASSAM      ECCLESIASTICUS
  EASTERN QUESTION, THE         ECGBERT (king of the West Saxons)
  EAST GRINSTEAD                ECGBERT (archbishop of York)
  EAST HAM                      ECGFRITH
  EASTHAMPTON                   ECGONINE
  EAST HAMPTON                  ECHEGARAY Y EIZAGUIRRE, JOSÉ
  EAST INDIA COMPANY            ÉCHELON
  EAST INDIES                   ECHIDNA
  EASTLAKE, SIR CHARLES LOCK



DYER, SIR EDWARD (d. 1607), English courtier and poet, son of Sir Thomas
Dyer, Kt., was born at Sharpham Park, Somersetshire. He was educated,
according to Anthony à Wood, either at Balliol College or at Broadgates
Hall, Oxford. He left the university without taking a degree, and after
some time spent abroad appeared at Queen Elizabeth's court. His first
patron was the earl of Leicester, who seems to have thought of putting
him forward as a rival to Sir Christopher Hatton in the queen's favour.
He is mentioned by Gabriel Harvey with Sidney as one of the ornaments of
the court. Sidney in his will desired that his books should be divided
between Fulke Greville (Lord Brooke) and Dyer. He was employed by
Elizabeth on a mission (1584) to the Low Countries, and in 1589 was sent
to Denmark. In a commission to inquire into manors unjustly alienated
from the crown in the west country he did not altogether please the
queen, but he received a grant of some forfeited lands in Somerset in
1588. He was knighted and made chancellor of the order of the Garter in
1596. William Oldys says of him that he "would not stoop to fawn," and
some of his verses seem to show that the exigencies of life at court
oppressed him. He was buried at St Saviour's, Southwark, on the 11th of
May 1607. Wood says that many esteemed him to be a Rosicrucian, and that
he was a firm believer in alchemy. He had a great reputation as a poet
among his contemporaries, but very little of his work has survived.
Puttenham in the _Arte of English Poesie_ speaks of "Maister Edward
Dyar, for Elegie most sweete, solempne, and of high conceit." One of the
poems universally accepted as his is "My Mynde to me a kingdome is."
Among the poems in _England's Helicon_ (1600), signed S.E.D., and
included in Dr A.B. Grosart's collection of Dyer's works (_Miscellanies
of the Fuller Worthies Library_, vol. iv., 1876) is the charming
pastoral "My Phillis hath the morninge sunne," but this comes from the
_Phillis_ of Thomas Lodge. Grosart also prints a prose tract entitled
_The Prayse of Nothing_ (1585). The _Sixe Idillia_ from Theocritus,
reckoned by J.P. Collier among Dyer's works, were dedicated to, not
written by, him.



DYER, JOHN (c. 1700-1758), British poet, the son of a solicitor, was
born in 1699 or 1700 at Aberglasney, in Carmarthenshire. He was sent to
Westminster school and was destined for the law, but on his father's
death he began to study painting. He wandered about South Wales,
sketching and occasionally painting portraits. In 1726 his first poem,
_Grongar Hill_, appeared in a miscellany published by Richard Savage,
the poet. It was an irregular ode in the so-called Pindaric style, but
Dyer entirely rewrote it into a loose measure of four cadences, and
printed it separately in 1727. It had an immediate and brilliant
success. _Grongar Hill_, as it now stands, is a short poem of only 150
lines, describing in language of much freshness and picturesque charm
the view from a hill overlooking the poet's native vale of Towy. A visit
to Italy bore fruit in _The Ruins of Rome_ (1740), a descriptive piece
in about 600 lines of Miltonic blank verse. He was ordained priest in
1741, and held successively the livings of Calthorp in Leicestershire,
Belchford (1751), Coningsby (1752), and Kirby-on-Bane (1756), the last
three being Lincolnshire parishes. He married, in 1741, a Miss Ensor,
said to be descended from the brother of Shakespeare. In 1757 he
published his longest work, the didactic blank-verse epic of _The
Fleece_, in four books, discoursing of the tending of sheep, of the
shearing and preparation of the wool, of weaving, and of trade in
woollen manufactures. The town took no interest in it, and Dodsley
facetiously prophesied that "Mr Dyer would be buried in woollen." He
died at Coningsby of consumption, on the 15th of December 1758.

  His poems were collected by Dodsley in 1770, and by Mr Edward Thomas
  in 1903 for the _Welsh Library_, vol. iv.



DYER, THOMAS HENRY (1804-1888), English historical and antiquarian
writer, was born in London on the 4th of May 1804. He was originally
intended for a business career, and for some time acted as clerk in a
West India house; but finding his services no longer required after the
passing of the Negro Emancipation Act, he decided to devote himself to
literature. In 1850 he published the _Life of Calvin_, a conscientious
and on the whole impartial work, though the character of Calvin is
somewhat harshly drawn, and his influence in the religious world
generally is insufficiently appreciated. Dyer's first historical work
was the _History of Modern Europe_ (1861-1864; 3rd ed. revised and
continued to the end of the 19th century, by A. Hassall, 1901), a
meritorious compilation and storehouse of facts, but not very readable.
The _History of the City of Rome_ (1865) down to the end of the middle
ages was followed by the _History of the Kings of Rome_ (1868), which,
upholding against the German school the general credibility of the
account of early Roman history, given in Livy and other classical
authors, was violently attacked by J.R. Seeley and the _Saturday
Review_, as showing ignorance of the comparative method. More favourable
opinions of the work were expressed by others, but it is generally
agreed that the author's scholarship is defective and that his views are
far too conservative. _Roma Regalis_ (1872) and _A Plea for Livy_ (1873)
were written in reply to his critics. Dyer frequently visited Greece and
Italy, and his topographical works are probably his best; amongst these
mention may be made of _Pompeii, its History, Buildings and Antiquities_
(1867, new ed. in Bohn's _Illustrated Library_), and _Ancient Athens,
its History, Topography and Remains_ (1873). His last publication was
_On Imitative Art_ (1882). He died at Bath on the 30th of January 1888.



DYMOKE, the name of an English family holding the office of king's
champion. The functions of the champion were to ride into Westminster
Hall at the coronation banquet, and challenge all comers to impugn the
king's title (see CHAMPION). The earliest record of the ceremony at the
coronation of an English king dates from the accession of Richard II. On
this occasion the champion was Sir John Dymoke (d. 1381), who held the
manor of Scrivelsby, Lincolnshire, in right of his wife Margaret,
granddaughter of Joan Ludlow, who was the daughter and co-heiress of
Philip Marmion, last Baron Marmion. The Marmions claimed descent from
the lords of Fontenay, hereditary champions of the dukes of Normandy,
and held the castle of Tamworth, Leicestershire, and the manor of
Scrivelsby, Lincolnshire. The right to the championship was disputed
with the Dymoke family by Sir Baldwin de Freville, lord of Tamworth, who
was descended from an elder daughter of Philip Marmion. The court of
claims eventually decided in favour of the owners of Scrivelsby on the
ground that Scrivelsby was held in grand serjeanty, that is, that its
tenure was dependent on rendering a special service, in this case the
championship.

Sir Thomas Dymoke (1428?-1471) joined a Lancastrian rising in 1469, and,
with his brother-in-law Richard, Lord Willoughby and Welles, was
beheaded in 1471 by order of Edward IV. after he had been induced to
leave sanctuary on a promise of personal safety. The estates were
restored to his son Sir Robert Dymoke (d. 1546), champion at the
coronations of Richard III., Henry VII. and Henry VIII., who
distinguished himself at the siege of Tournai and became treasurer of
the kingdom. His descendants acted as champions at successive
coronations. Lewis Dymoke (d. 1820) put in an unsuccessful claim before
the House of Lords for the barony of Marmion. His nephew Henry
(1801-1865) was champion at the coronation of George IV. He was
accompanied on that occasion by the duke of Wellington and Lord Howard
of Effingham. Henry Dymoke was created a baronet; he was succeeded by
his brother John, rector of Scrivelsby (1804-1873), whose son Henry
Lionel died without issue in 1875, when the baronetcy became extinct,
the estate passing to a collateral branch of the family. After the
coronation of George IV. the ceremony was allowed to lapse, but at the
coronation of King Edward VII. H.S. Dymoke bore the standard of England
in Westminster Abbey.



DYNAMICS (from Gr. [Greek: dynamis], strength), the name of a branch of
the science of Mechanics (q.v.). The term was at one time restricted to
the treatment of motion as affected by force, being thus opposed to
Statics, which investigated equilibrium or conditions of rest. In more
recent times the word has been applied comprehensively to the action of
force on bodies either at rest or in motion, thus including "dynamics"
(now termed kinetics) in the restricted sense and "statics."

ANALYTICAL DYNAMICS.--The fundamental principles of dynamics, and their
application to special problems, are explained in the articles MECHANICS
and MOTION, LAWS OF, where brief indications are also given of the more
general methods of investigating the properties of a dynamical system,
independently of the accidents of its particular constitution, which
were inaugurated by J.L. Lagrange. These methods, in addition to the
unity and breadth which they have introduced into the treatment of pure
dynamics, have a peculiar interest in relation to modern physical
speculation, which finds itself confronted in various directions with
the problem of explaining on dynamical principles the properties of
systems whose ultimate mechanism can at present only be vaguely
conjectured. In determining the properties of such systems the methods
of analytical geometry and of the infinitesimal calculus (or, more
generally, of mathematical analysis) are necessarily employed; for this
reason the subject has been named Analytical Dynamics. The following
article is devoted to an outline of such portions of general dynamical
theory as seem to be most important from the physical point of view.


  1. _General Equations of Impulsive Motion._

  The systems contemplated by Lagrange are composed of discrete
  particles, or of rigid bodies, in finite number, connected (it may be)
  in various ways by invariable geometrical relations, the fundamental
  postulate being that the position of every particle of the system at
  any time can be completely specified by means of the instantaneous
  values of a finite number of independent variables q1, q2, ... q_n,
  each of which admits of continuous variation over a certain range, so
  that if x, y, z be the Cartesian co-ordinates of any one particle, we
  have for example

    x = [f](q1, q2, ... q_n), y = &c., z = &c.,   (1)

  where the functions [f] differ (of course) from particle to particle.
  In modern language, the variables q1, q2, ... q_n are _generalized
  co-ordinates_ serving to specify the _configuration_ of the system;
  their derivatives with respect to the time are denoted by q`1, q`2,
  ... q`_n, and are called the _generalized components of velocity_. The
  continuous sequence of configurations assumed by the system in any
  actual or imagined motion (subject to the given connexions) is called
  the _path_.


    Impulsive motion.

  For the purposes of a connected outline of the whole subject it is
  convenient to deviate somewhat from the historical order of
  development, and to begin with the consideration of _impulsive_
  motion. Whatever the actual motion of the system at any instant, we
  may conceive it to be generated instantaneously from rest by the
  application of proper impulses. On this view we have, if x, y, z be
  the rectangular co-ordinates of any particle m,

    mx` = X', my` = Y', mz` = Z',   (2)

  where X', Y', Z' are the components of the impulse on m. Now let
  [delta]x, [delta]y, [delta]z be any infinitesimal variations of x, y,
  z which are consistent with the connexions of the system, and let us
  form the equation

    [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) =
       [Sigma](X'[delta]x + Y'[delta]y + Z'[delta]z),   (3)

  where the sign [Sigma] indicates (as throughout this article) a
  summation extending over all the particles of the system. To transform
  (3) into an equation involving the variations [delta]q1, [delta]q2,
  ... of the generalized co-ordinates, we have

          dPx        dPx
    x` = ---- q`1 + ---- q`2 + ..., &c., &c.   (4)
         dPq1       dPq2

               dPx              dPx
    [delta]x = ---- [delta]q1 + ---- [delta]q2 + ..., &c., &c.   (5)
               dPq1             dPq2

  and therefore

    [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) =
        (A11q`1 + A12q`2 + ...)[delta]q1 +
        (A21q`1 + A22q`2 + ...)[delta]q2 + ...,   (6)

  where
                     _                                 _
                    |  / dPx \²    / dPy \²    / dPz \² |               \
    A_rr = [Sigma]m | ( ----- ) + ( ----- ) + ( ----- ) |,               |
                    |_ \dPq_r/     \dPq_r/     \dPq_r/ _|                |
                     _                                        _           > (7)
                    |  dPx   dPx     dPy   dPy     dPz   dPz   |         |
    A_rs = [Sigma]m | ----- ----- + ----- ----- + ----- -----  | = A_sr. |
                    |_dPq_r dPq_s   dPq_r dPq_s   dPq_r dPq_s _|        /

  If we form the expression for the kinetic energy [Tau] of the system,
  we find

    2[Tau] = [Sigma]m(x`² + y`² + z`²) = A11q`1² + A22q`2² + ...
       + 2A12q`1q`2 + ... (8)

  The coefficients A11, A22, ... A12, ... are by an obvious analogy
  called the _coefficients of inertia_ of the system; they are in
  general functions of the co-ordinates q1, q2, ... . The equation (6)
  may now be written

                                                     dP[Tau]             dP[Tau]
    [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) = ------- [delta]q1 + ------- [delta]q2 + ... (9)
                                                      dPq`1               dPq`2

  This maybe regarded as the cardinal formula in Lagrange's method. For
  the right-hand side of (3) we may write

    [Sigma](X'[delta]x + Y'[delta]y + Z'[delta]z) = Q'1[delta]q1 + Q'2[delta]q2 + ... ,  (10)

  where

                   /   dPx       dPy       dPz \
    Q'_r = [Sigma]( X'----- + Y'----- + Z'----- ).  (11)
                   \  dPq_r     dPq_r     dPq_r/

  The quantities Q1, Q2, ... are called the _generalized components of
  impulse_. Comparing (9) and (10), we have, since the variations
  [delta]q1, [delta]q2,... are independent,

    dP[Tau]        dP[Tau]
    ------- = Q'1, ------- = Q'2, ...  (12)
     dPq`1          dPq`2

  These are the general equations of impulsive motion. It is now usual
  to write

          dP[Tau]
    p_r = -------   (13)
          dPq`_r

  The quantities p1, p2, ... represent the effects of the several
  component impulses on the system, and are therefore called the
  _generalized components of momentum_. In terms of them we have

    [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) = p1[delta]q1 + p2[delta]q2 + ...  (14)

  Also, since [Tau] is a homogeneous quadratic function of the
  velocities q`1, q`2 ...,

    2[Tau] = p1q`1 + p2q`2 + ...  (15)

  This follows independently from (14), assuming the special variations
  [delta]x = x`dt, &c., and therefore [delta]q1 = q`1dt, [delta]q2 =
  q`2dt, ...


    Reciprocal theorems.

  Again, if the values of the velocities and the momenta in any other
  motion of the system through the same configuration be distinguished
  by accents, we have the identity

    p1q`'1 + p2q`'2 + ... = p'1q`1 + p'2q`2 + ...,   (16)

  each side being equal to the symmetrical expression

    A11q`1q''1 + A22q`2q`'2 + ... + A12(q`1q`'2 + q`'1q`2) + ...  (17)

  The theorem (16) leads to some important reciprocal relations. Thus,
  let us suppose that the momenta p1, p2, ... all vanish with the
  exception of p1, and similarly that the momenta p'1, p'2, ... all
  vanish except p'2. We have then p1q`'1 = p'2q`2, or

    q`2 : p1 = q`'1 : p'2                       (18)

  The interpretation is simplest when the co-ordinates q1, q2 are both
  of the same kind, e.g. both lines or both angles. We may then
  conveniently put p1 = p'2, and assert that the velocity of the first
  type due to an impulse of the second type is equal to the velocity of
  the second type due to an equal impulse of the first type. As an
  example, suppose we have a chain of straight links hinged each to the
  next, extended in a straight line, and free to move. A blow at right
  angles to the chain, at any point P, will produce a certain velocity
  at any other point Q; the theorem asserts that an equal velocity will
  be produced at P by an equal blow at Q. Again, an impulsive couple
  acting on any link A will produce a certain angular velocity in any
  other link B; an equal couple applied to B will produce an equal
  angular velocity in A. Also if an impulse F applied at P produce an
  angular velocity [omega] in a link A, a couple Fa applied to A will
  produce a linear velocity [omega]a at P. Historically, we may note
  that reciprocal relations in dynamics were first recognized by H.L.F.
  Helmholtz in the domain of acoustics; their use has been greatly
  extended by Lord Rayleigh.


    Velocities in terms of momenta.

  The equations (13) determine the momenta p1, p2,... as linear
  functions of the velocities q`1, q`2,... Solving these, we can
  express q`1, q`2 ... as linear functions of p1, p2,... The
  resulting equations give us the velocities produced by any given
  system of impulses. Further, by substitution in (8), we can express
  the kinetic energy as a homogeneous quadratic function of the momenta
  p1, p2,... The kinetic energy, _as so expressed_, will be denoted by
  [Tau]´; thus

    2[Tau]´ = A´11p1² + A´22p2² + ... + 2A´12p - p2 + ...   (19)

  where A´11, A´22,... A´12,... are certain coefficients depending on
  the configuration. They have been called by Maxwell the _coefficients
  of mobility_ of the system. When the form (19) is given, the values
  of the velocities in terms of the momenta can be expressed in a
  remarkable form due to Sir W.R. Hamilton. The formula (15) may be
  written

    p1q`1 + p2q`2 + ... = [Tau] + [Tau]´, ...   (20)

  where [Tau] is supposed expressed as in (8), and [Tau]´ as in (19).
  Hence if, for the moment, we denote by [delta] a variation affecting
  the velocities, and therefore the momenta, but not the configuration,
  we have

    p1[delta]q`1 + q`1[delta]p + p2[delta]q`2 + q`2[delta]p2 + ... = [delta][Tau] + [delta][Tau]´

      dP[Tau]              dP[Tau]                    dP[Tau]´             dP[Tau]´
    = ------- [delta]q`1 + ------- [delta]q`2 + ... + -------- [delta]p1 + -------- [delta]p2 + ...  (21)
      dPq`1                dPq`2                       dPp1                 dPp2

  In virtue of (13) this reduces to

                                        dP[Tau]´            dP[Tau]´
    q`1[delta]p1 + q`2[delta]p2 + ... = ------- [delta]p1 + ------- [delta]p2  + ...  (22)
                                         dPp1                dPp2

  Since [delta]p1, [delta]p2, ... may be taken to be independent, we
  infer that

          dP[Tau]´       dP[Tau]´
    q`1 = -------, q`2 = -------, ...  (23)
           dPp1           dPp2

  In the very remarkable exposition of the matter given by James Clerk
  Maxwell in his _Electricity and Magnetism_, the Hamiltonian
  expressions (23) for the velocities in terms of the impulses are
  obtained directly from first principles, and the formulae (13) are
  then deduced by an inversion of the above argument.


    Routh's modification.

  An important modification of the above process was introduced by E.J.
  Routh and Lord Kelvin and P.G. Tait. Instead of expressing the kinetic
  energy in terms of the velocities alone, or in terms of the momenta
  alone, we may express it in terms of the velocities corresponding to
  some of the co-ordinates, say q1, q2, ... q_m, and of the momenta
  corresponding to the remaining co-ordinates, which (for the sake of
  distinction) we may denote by [chi], [chi]', [chi]", .... Thus, [Tau]
  being expressed as a homogeneous quadratic function of q`1, q`2, ...
  q`_m, [chi]`, [chi]`', [chi]`", ..., the momenta corresponding to the
  co-ordinates [chi], [chi]', [chi]", ... may be written

               dP[Tau]               dP[Tau]                dP[Tau]
    [kappa]  = --------, [kappa]' = ---------, [kappa]" = ------------, ...  (24)
               dP[chi]`             dP[chi]`'              dP[.[chi]`"

  These equations, when written out in full, determine [chi]`, [chi]`',
  [chi]`", ... as linear functions of q`1, q`2, ... q`_m, [kappa],
  [kappa]', [kappa]",... We now consider the function

    R = [Tau] - [kappa][chi]' - [kappa]'[chi]]`' - [kappa]"[chi]]`" - ...,  (25)

  supposed expressed, by means of the above relations in terms of q`1,
  q`2, ... q`_m, [kappa], [kappa]', [kappa]",... Performing the
  operation [delta] on both sides of (25), we have

     dPR                        dPR                           dP[Tau]                    dP[Tau]
    ----- [delta]q`1 + ... + --------- [delta][kappa] + ... = ------- [delta]q`1 + ... + -------- [delta][chi]` + ...
    dPq`1                    dP[kappa]                         dPq`1                     dP[chi]`

       - [kappa]dP[chi]` - [chi]`[delta][kappa] - ... ,   (26)

  where, for brevity, only one term of each type has been exhibited.
  Omitting the terms which cancel in virtue of (24), we have

     dPR                        dPR                           dP[Tau]
    ----- [delta]q`1 + ... + --------- [delta][kappa] + ... = ------- [delta]q`1 + ... - [chi]`[delta][kappa] - ...  (27)
    dPq`1                    dP[kappa]                        dPq`1

  Since the variations [delta]q1, [delta]q2, ... [delta]q_m,
  [delta][kappa], [delta][kappa]', [delta][kappa]", ... may be taken to
  be independent, we have

         dP[Tau]     dPR        dP[Tau]     dPR
    p1 = -------  = -----, p2 = -------  = -----, ...  (28)
          dPq`1     dPq`1        dPq`2     dPq`2

  and

                  dPR                    dPR                      dPR
    [chi]` = - ---------, [chi]`' = - ----------, [chi]]`" = - ---------, ...  (29)
               dP[kappa]              dP[kappa]'               dP[kappa]"

  An important property of the present transformation is that, when
  expressed in terms of the new variables, the kinetic energy is the sum
  of two homogeneous quadratic functions, thus

    [Tau] = [@] + K,  (30)

  where [@] involves the velocities q`1, q`2, ... q`_m alone, and K the
  momenta [kappa], [kappa]', [kappa]", ... alone. For in virtue of (29)
  we have, from (25),

                 /            dPR                  dPR                    dPR          \
    [Tau] = R - ( [kappa]  --------- + [kappa]' ---------- + [kappa]" ----------- + ... ),  (31)
                 \         dP[kappa]            dP[kappa]'             dP[kappa]"      /

  and it is evident that the terms in R which are bilinear in respect of
  the two sets of variables q`1, q`2, ... q`_m and [kappa], [kappa]',
  [kappa]", ... will disappear from the right-hand side.


    Maximum and minimum energy.

  It may be noted that the formula (30) gives immediate proof of two
  important theorems due to Bertrand and to Lord Kelvin respectively.
  Let us suppose, in the first place, that the system is started by
  given impulses of certain types, but is otherwise free. J.L.F.
  Bertrand's theorem is to the effect that the kinetic energy is
  _greater_ than if by impulses of the remaining types the system were
  constrained to take any other course. We may suppose the co-ordinates
  to be so chosen that the constraint is expressed by the vanishing of
  the velocities q`1, q`2, ... q`_m, whilst the given impulses are
  [kappa], [kappa]', [kappa]",... Hence the energy in the actual motion
  is greater than in the constrained motion by the amount [@].

  Again, suppose that the system is started with prescribed velocity
  components q`1, q`2, ... q`_m, by means of proper impulses of
  the corresponding types, but is otherwise free, so that in the motion
  actually generated we have [kappa] = 0, [kappa]' = 0, [kappa]" = 0,
  ... and therefore K = 0. The kinetic energy is therefore _less_ than
  in any other motion consistent with the prescribed velocity-conditions
  by the value which K assumes when [kappa], [kappa]', [kappa]", ...
  represent the impulses due to the constraints.

  Simple illustrations of these theorems are afforded by the chain of
  straight links already employed. Thus if a point of the chain be held
  fixed, or if one or more of the joints be made rigid, the energy
  generated by any given impulses is less than if the chain had
  possessed its former freedom.


  2. _Continuous Motion of a System._

    Lagrange's equations.

  We may proceed to the continuous motion of a system. The equations of
  motion of any particle of the system are of the form

    mx¨ = X, my¨ = Y, mz¨ = Z  (1)

  Now let x + [delta]x, y + [delta]y, z + [delta]z be the co-ordinates
  of m in any arbitrary motion of the system differing infinitely little
  from the actual motion, and let us form the equation

    [Sigma]m(x¨[delta]x + y¨[delta]y + z¨[delta]z) =
       [Sigma](X[delta]x + Y[delta]y + Z[delta]z) (2)

  Lagrange's investigation consists in the transformation of (2) into an
  equation involving the independent variations [delta]q1, [delta]q2,
  ... [delta]q_n.

  It is important to notice that the symbols [delta] and d/dt are
  commutative, since

                d                  dx   d
    [delta]x` = --(x + [delta]x) - -- = --[delta]x, &c. (3)
                dt                 dt   dt

  Hence

                                                     d
    [Sigma]m(x¨[delta]x + y¨[delta]y + z¨[delta]z) = -- [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z)
                                                     dt
      - [Sigma]m(x`[delta]x` + y`[delta]y` + z`[delta]z`)

        d
      = --(p1[delta]q1 + p2[delta]q2 + ...) - [delta][Tau],  (4)
        dt

  by § 1 (14). The last member may be written

    p`1[delta]q1 + p1[delta]q`1 + p`2[delta]q2 + p2[delta]q`2 + ...

        dP[Tau]              dP[Tau]             dP[Tau]              dP[Tau]
      - ------- [delta]q`1 - ------- [delta]q1 - ------- [delta]q`2 - ------- [delta]q2 - ... (5)
         dPq`1                dPq1                dPq`2                dPq2

  Hence, omitting the terms which cancel in virtue of § 1 (13), we find

                                                      /     dP[Tau]\               /     dP[Tau]\
    [Sigma]m(x¨[delta]x + y¨[delta]y + z¨[delta]z) = (p`1 - ------- ) [delta]q1 + (p`2 - ------- ) [delta]q2 + ... (6)
                                                      \      dPq1  /               \       dPq2 /

  For the right-hand side of (2) we have

    [Sigma](X[delta]x + Y[delta]y + Z[delta]z) = Q1[delta]q1 + Q2[delta]q2  + ..., (7)

                      /   dPx       dPy       dPz \
  where Q_r = [Sigma]( X ----- + Y ----- + Z ----- )  (8)
                      \  dPq_r     dPq_r     dPq_r/

  The quantities Q1, Q2, ... are called the _generalized components of
  force_ acting on the system.

  Comparing (6) and (7) we find

          dP[Tau]             dP[Tau]
    p`1 - ------- = Q1, p`2 - ------- = Q2, ...,  (9)
           dPq`1               dPq`2

  or, restoring the values of p1, p2, ...,

    d   /dP[Tau]\    dP[Tau]       d   /dP[Tau]\    dP[Tau]
    -- ( ------- ) - ------- = Q1, -- ( ------- ) - ------- = Q2, ... (10)
    dt  \ dPq`1 /     dPq1         dt  \ dPq`2 /      dPq2

  These are Lagrange's general equations of motion. Their number is of
  course equal to that of the co-ordinates q1, q2, ... to be determined.

  Analytically, the above proof is that given by Lagrange, but the
  terminology employed is of much more recent date, having been first
  introduced by Lord Kelvin and P.G. Tait; it has greatly promoted the
  physical application of the subject. Another proof of the equations
  (10), by direct transformation of co-ordinates, has been given by
  Hamilton and independently by other writers (see MECHANICS), but the
  variational method of Lagrange is that which stands in closest
  relation to the subsequent developments of the subject. The chapter of
  Maxwell, already referred to, is a most instructive commentary on the
  subject from the physical point of view, although the proof there
  attempted of the equations (10) is fallacious.

  In a "conservative system" the work which would have to be done by
  extraneous forces to bring the system from rest in some standard
  configuration to rest in the configuration (q1, q2, ... q_n) is
  independent of the path, and may therefore be regarded as a definite
  function of q1, q2, ... q_n. Denoting this function (the _potential
  energy_) by V, we have, if there be no extraneous force on the system,

    [Sigma](X[delta]x + Y[delta]y + Z[delta]z) = - [delta]V,  (11)

  and therefore

           dPV          dPV
    Q1 = - ----, Q2 = - ----, ....  (12)
           dPq1         dPq2

  Hence the typical Lagrange's equation may be now written in the form

    d   /dP[Tau]\    dP[Tau]      dPV
    -- ( ------- ) - ------- = - -----,  (13)
    dt  \dPq`_r /     dPq_r      dPq_r

  or, again,

              dP
    p`_r = - ----- (V - [Tau])  (14)
             dPq_r

  It has been proposed by Helmholtz to give the name _kinetic potential_
  to the combination V - [Tau].

  As shown under MECHANICS, § 22, we derive from (10)

    d[Tau]
    ------ = Q1q`1 + Q2q`2 + ...,  (15)
      dt

  and therefore in the case of a conservative system free from
  extraneous force,

    d
    --([Tau] + V) = 0 or [Tau] + V = const.,  (16)
    dt

  which is the equation of energy. For examples of the application of
  the formula (13) see MECHANICS, § 22.


  3. _Constrained Systems._

    Case of varying relations.

  It has so far been assumed that the geometrical relations, if any,
  which exist between the various parts of the system are of the type §
  1 (1), and so do not contain t explicitly. The extension of Lagrange's
  equations to the case of "varying relations" of the type

    x = f(t, q1, q2,...q_n), y = &c., z = &c.,  (1)

  was made by J.M.L. Vieille. We now have

         dPx   dPx        dPx
    x` = --- + ---- q`1 + ---- q`2 + ..., &c., &c.,  (2)
         dPt   dPq1       dPq2

          dPx              dPx
    dPx = ---- [delta]q1 + ---- [delta]q2 + ..., &c., &c.,  (3)
          dPq1             dPq2

  so that the expression § 1 (8) for the kinetic energy is to be
  replaced by

    2[Tau] = [alpha]0 + 2[alpha]1q`1 + 2[alpha]2q`2 + ... + A11q`1² + A22q`2² + ... + A12q`1q`2 + ..., (4)

  where
                   _                           _         \
                  | /dPx\²    /dPy\²    /dPz\²  |         |
    a0 = [Sigma]m |( --- ) + ( --- ) + ( --- )  |,        |
                  |_\dPt/     \dPt/     \dPt/  _|         |
                    _                                 _    >  (5)
                   | dPx  dPx    dPy  dPy    dPz  dPz  |  |
    a_r = [Sigma]m | --- ----- + --- ----- + --- ----- |, |
                   |_dPt dPq_r   dPt dPq_r   dPt dPq_r_|  |
                                                         /

  and the forms of A_rr, A_rs are as given by § 1 (7). It is to be
  remembered that the coefficients [alpha]0, [alpha]1, [alpha]2, ...
  A11, A22, ... A12 ... will in general involve t explicitly as well as
  implicitly through the co-ordinates q1, q2,... Again, we find

    [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) =

        ([alpha]1 + A11q`1 + A12q`2 + ...)[delta]q1
            + ([alpha]2 + A21q`1 + A22q`2 + ...)dPq2 + ...

          dP[Tau]             dP[Tau]
        = ------- [delta]q1 + ------- [delta]q2 + ...
           dPq`1               dPq`2

        = p1[delta]q1 + p2[delta]q2 + ...,  (6)

  where p_r is defined as in § 1 (13). The derivation of Lagrange's
  equations then follows exactly as before. It is to be noted that the
  equation § 2 (15) does not as a rule now hold. The proof involved the
  assumption that [Tau] is a homogeneous quadratic function of the
  velocities q`1, q`2....

  It has been pointed out by R.B. Hayward that Vieille's case can be
  brought under Lagrange's by introducing a new co-ordinate ([chi]) in
  place of t, so far as it appears explicitly in the relations (1). We
  have then

    2[Tau] = [alpha]0[chi]`² + 2([alpha]1q`1 + [alpha]2q`2 + ...)[chi]`
        + A11q`1² + A22q`2² + ... + 2A12q`1q`2 + .... (7)

  The equations of motion will be as in § 2 (10), with the additional
  equation

    d  dP[Tau]    dP[Tau]
    -- -------- - ------- = X,  (8)
    dt dP[chi]`   dP[chi]

  where X is the force corresponding to the co-ordinate [chi]. We may
  suppose X to be adjusted so as to make [chi]¨ = 0, and in the
  remaining equations nothing is altered if we write t for [chi] before,
  instead of after, the differentiations. The reason why the equation §
  2 (15) no longer holds is that we should require to add a term X[chi]`
  on the right-hand side; this represents the rate at which work is
  being done by the constraining forces required to keep [chi]`
  constant.

  As an example, let x, y, z be the co-ordinates of a particle relative
  to axes fixed in a solid which is free to rotate about the axis of z.
  If [phi] be the angular co-ordinate of the solid, we find without
  difficulty

    2[Tau] = m(x`² + y`² +z`²) + 2[phi]`m(xy` - yx`) + {I + m(x² + y²)}[phi]`², (9)

  where I is the moment of inertia of the solid. The equations of
  motion, viz.

    d  dP[Tau]  dP[Tau]     d  dP[Tau]   dP[Tau]      d  dP[Tau]   dP[Tau]
    -- ------ - ------ = X, -- ------- - ------- = Y, -- ------- - ------- = Z, (10)
    dt  dPx`     dPx        dt   dPy`      dPy        dt   dPz`      dPz

      d   dP[Tau]   dP[Tau]
  and -- -------- - ------- = [Phi],  (11)
      dt dP[phi]`   dP[phi]

  become

    m(x¨ - 2[phi]`y` - x[phi]`² - y[phi]¨) = X, m(y¨ + 2[phi]`x` - y[phi]`² + x[phi]`) = Y, mz¨ = Z, (12)
          _                                    _
      d  | /            \                       |
  and -- |(I + m(x² + y²)) [phi]` + m(xy` - yx`)| = [Phi].  (13)
      dt |_\            /                      _|

  If we suppose [Phi] adjusted so as to maintain [phi]¨ = 0, or (again)
  if we suppose the moment of inertia I to be infinitely great, we
  obtain the familiar equations of motion relative to moving axes, viz.

    m(x¨ - 2[omega]y` - [omega]²x) = X, m(y¨ + 2[omega]x` - [omega]²y) = Y, mz¨ = Z, (14)

  where [omega] has been written for [phi]. These are the equations
  which we should have obtained by applying Lagrange's rule at once to
  the formula

    2[Tau] = m(x`² + y`² + z`²) + 2m[omega](xy` - yx`) + m[omega]²(x² + y²), (15)

  which gives the kinetic energy of the particle referred to axes
  rotating with the constant angular velocity [omega]. (See MECHANICS, §
  13.)

  More generally, let us suppose that we have a certain group of
  co-ordinates [chi], [chi]', [chi]", ... whose absolute values do not
  affect the expression for the kinetic energy, and that by suitable
  forces of the corresponding types the velocity-components [chi]`,
  [chi]`', [chi]`", ... are maintained constant. The remaining
  co-ordinates being denoted by q1, q2, ... q_n, we may write

    2[Tau] = [@] + [Tau]0 + 2([alpha]1q`1 + [alpha]2q`2 + ...)[chi]`
        + 2([alpha]'1q`1 + [alpha]'2q`2 + ...)[chi]`' + ...,  (16)

  where [@] is a homogeneous quadratic function of the velocities q`1,
  q`2, ... q`_n of the type §1 (8), whilst [Tau]0 is a homogeneous
  quadratic function of the velocities [chi]`,[chi]`', [chi]`", ...
  alone. The remaining terms, which are bilinear in respect of the two
  sets of velocities, are indicated more fully. The formulae (10) of § 2
  give n equations of the type

    d  /dP[@]\     /dP[@]\                                  dP[Tau]0
    --( ----- ) - ( ----- ) + (r, 1)q`1 + (r, 2)q`2 + ... - -------- = Q_r (17)
    dt \dPq_r/     \dPq_r/                                    dPq_r

  where

              /dPa_r   dPa_s\           /dPa'_r   dPa'_s\
    (r, s) = ( ----- - ----- )[chi]` + ( ------ - ------ )[chi]`' + .... (18)
              \dPq_s   dPq_r/           \dPq_s     dPq_r/

  These quantities (r, s) are subject to the relations

    (r, s) = -(s, r), (r, r) = 0  (19)

  The remaining dynamical equations, equal in number to the co-ordinates
  [chi], [chi]', [chi]", ..., yield expressions for the forces which
  must be applied in order to maintain the velocities [chi]`, [chi]`',
  [chi]`", ... constant; they need not be written down. If we follow the
  method by which the equation of energy was established in § 2, the
  equations (17) lead, on taking account of the relations (19), to

    d
    --([@] - [Tau]0) = Q1q`1 + Q2q`2 + ... + Q_nq`_n,  (20)
    dt

  or, in case the forces Q_r depend only on the co-ordinates q1, q2, ...
  q_n and are conservative,

    [@] + V - [Tau]0 = const.  (21)

  The conditions that the equations (17) should be satisfied by zero
  values of the velocities q`1, q`2, ... q`_n are

            dP[Tau]0
    Q_r = - --------,  (22)
             dPq_r

  or in the case of conservative forces

    dP
    ------ (V - [Tau]0) = 0,  (23)
    dPq_r

  i.e. the value of V - [Tau]0 must be _stationary_.


    Rotating axes.

  We may apply this to the case of a system whose configuration relative
  to axes rotating with constant angular velocity ([omega]) is defined
  by means of the n co-ordinates q1, q2, ... q_n. This is important on
  account of its bearing on the kinetic theory of the tides. Since the
  Cartesian co-ordinates x, y, z of any particle m of the system
  relative to the moving axes are functions of q1, q2, ... q_n, of the
  form § 1 (1), we have, by (15)

    2[@] = [Sigma]m(x`² + y`² + z`²), 2[Tau]0 = [omega]²[Sigma]m(x² + y²),  (24)

                  /  dPy      dPx \
    a_r= [Sigma]m( x----- - y----- ),  (25)
                  \ dPq_r    dPq_r/

  whence

                                 dP(x, y)
    (r, s) = 2[omega]·[Sigma]m ------------.  (26)
                               dP(q_s, q_r)

  The conditions of relative equilibrium are given by (23).

  It will be noticed that this expression V - [Tau]0, which is to be
  stationary, differs from the true potential energy by a term which
  represents the potential energy of the system in relation to
  fictitious "centrifugal forces." The question of stability of relative
  equilibrium will be noticed later (§ 6).

  It should be observed that the remarkable formula (20) may in the
  present case be obtained directly as follows. From (15) and (14) we
  find

    d[Tau]   d
    ------ = --([@] + [Tau]0) + [omega]·[Sigma]m(xy¨ - yx¨)
      dt     dt

        d
      = --([@] - [Tau]0) + [omega]·[Sigma](xY - yX).  (27)
        dt

  This must be equal to the rate at which the forces acting on the
  system do work, viz. to

    [omega][Sigma](xY - yX) + Q1q`1 + Q2q`2 + ... + Q_nq`_n,

  where the first term represents the work done in virtue of the
  rotation.


    Constrained systems.

  We have still to notice the modifications which Lagrange's equations
  undergo when the co-ordinates q1, q2, ... q_n are not all
  independently variable. In the first place, we may suppose them
  connected by a number m ( < n) of relations of the type

    A(t, q1, q2, ... q_n) = 0, B(t, q1, q2, ... q_n) = 0, &c.  (28)

  These may be interpreted as introducing partial constraints into a
  previously free system. The variations [delta]q1, [delta]q2, ...
  [delta]q_n in the expressions (6) and (7) of § 2 which are to be
  equated are no longer independent, but are subject to the relations

    dPA              dPA                       dPB              dPB
    ---- [delta]q1 + ---- [delta]q2 + ... = 0, ---- [delta]q1 + ---- [delta]q2 + ... = 0, &c.  (29)
    dPq1             dPq2                      dPq1             dPq2

  Introducing indeterminate multipliers [lambda], µ, ..., one for each
  of these equations, we obtain in the usual manner n equations of the
  type

    d  dP[Tau]   dP[Tau]                   dPA       dPB
    -- ------- - ------- = Q_r + [lambda] ----- + µ ----- + ..., (30)
    dt dPq`_r     dPq_r                   dPq_r     dPq_r

  in place of § 2 (10). These equations, together with (28), serve to
  determine the n co-ordinates q1, q2, ... q_n and the m multipliers
  [lambda], µ, ....

  When t does not occur explicitly in the relations (28) the system is
  said to be _holonomic_. The term connotes the existence of integral
  (as opposed to differential) relations between the co-ordinates,
  independent of the time.

  Again, it may happen that although there are no prescribed relations
  between the co-ordinates q1, q2, ... q_n, yet from the circumstances
  of the problem certain geometrical conditions are imposed on their
  _variations_, thus

    A1[delta]q1 + A2[delta]q2 + ... = 0, B1[delta]q1 + B2[delta]q2 + ... = 0, &c., (31)

  where the coefficients are functions of q1, q2, ... q_n and (possibly)
  of t. It is assumed that these equations are not integrable as regards
  the variables q1, q2, ... q_n; otherwise, we fall back on the previous
  conditions. Cases of the present type arise, for instance, in ordinary
  dynamics when we have a solid rolling on a (fixed or moving) surface.
  The six co-ordinates which serve to specify the position of the solid
  at any instant are not subject to any necessary relation, but the
  conditions to be satisfied at the point of contact impose three
  conditions of the form (31). The general equations of motion are
  obtained, as before, by the method of indeterminate multipliers, thus

    d  dP[Tau]   dP[Tau]
    -- ------- - ------- = Q_r + [lambda]A_r + µB_r + ...  (32)
    dt dPq`_r     dPq_r

  The co-ordinates q1, q2, ... q_n, and the indeterminate multipliers
  [lambda], µ, ..., are determined by these equations and by the
  velocity-conditions corresponding to (31). When t does not appear
  explicitly in the coefficients, these velocity-conditions take the
  forms

    A1q`1 + A2q`2 + ... = 0, B1q`1 + B2q`2 + ... = 0, &c.  (33)

  Systems of this kind, where the relations (31) are not integrable, are
  called _non-holonomic_.


  4. _Hamiltonian Equations of Motion._

  In the Hamiltonian form of the equations of motion of a conservative
  system with unvarying relations, the kinetic energy is supposed
  expressed in terms of the _momenta_ p1, p2, ... and the co-ordinates
  q1, q2, ..., as in § 1 (19). Since the symbol [delta] now denotes a
  variation extending to the co-ordinates as well as to the momenta, we
  must add to the last member of § 1 (21) terms of the types

    dP[Tau]             dP[Tau]'
    ------- [delta]q1 + -------- [delta]q1 + ...  (1)
     dPq1                 dPq1

  Since the variations [delta]p1, [delta]p2, ... [delta]q1, [delta]q2,
  ... may be taken to be independent, we infer the equations § 1 (23) as
  before, together with

    dP[Tau]    dP[Tau]´  dP[Tau]     dP[Tau]´
    ------ = - --------, ------- = - --------, ...,  (2)
     dPq1        dPq1     dPq2         dPq2

  Hence the Lagrangian equations § 2 (14) transform into

             dP                      dP
    p`1 = - ----([Tau]´ + V), p`2 = ---- ([Tau]´ + V), ...  (3)
            dPq1                    dPq2

  If we write

    H = [Tau]´ + V,  (4)

  so that H denotes the _total energy_ of the system, supposed expressed
  in terms of the new variables, we get

            dPH           dPH
    p`1 = - ----, p`2 = - ----, ...  (5)
            dPq1          dPq2

  If to these we join the equations

          dPH         dPH
    q`1 = ----, q`2 = ----, ...,  (6)
          dPp1        dPp2


  which follow at once from § 1 (23), since V does not involve p1, p2,
  ..., we obtain a complete system of differential equations _of the
  first order_ for the determination of the motion.

  The equation of energy is verified immediately by (5) and (6), since
  these make

    dH   dPH        dPH              dPH        dPH
    -- = ---- p`1 + ---- p`2 + ... + ---- q`1 + ---- q`2 + ... = 0. (7)
    dt   dPp1       dPp2             dPq1       dPq2

  The Hamiltonian transformation is extended to the case of varying
  relations as follows. Instead of (4) we write

    H = p1q`1 + p2q`2 + ... - [Tau] + V,  (8)

  and imagine H to be expressed in terms of the momenta p1, p2, ..., the
  co-ordinates q1, q2, ..., and the time. The internal forces of the
  system are assumed to be conservative, with the potential energy V.
  Performing the variation [delta] on both sides, we find

                                    dP[Tau]             dPV
    [delta]H = q`1[delta]p1 + ... - ------- [delta]q1 + ---- [delta]q + ...,  (9)
                                     dPq1               dPq1

  terms which cancel in virtue of the definition of p1, p2, ... being
  omitted. Since [delta]p1, [delta]p2, ..., [delta]q1, [delta]q2, ...
  may be taken to be independent, we infer

          dPH         dPH
    q`1 = ----, q`2 = ----, ...,  (10)
          dPp1        dPp2

  and

     dP                  dPH    dP                 dPH
    ---- ([Tau] - V) = - ----, ----([Tau] - V) = - ----, ....  (11)
    dPq1                 dPq1  dPq2                dPq2

  It follows from (11) that

            dPH           dPH
    p`1 = - ----, p`2 = - ----, ....  (12)
            dPq1          dPq2

  The equations (10) and (12) have the same form as above, but H is no
  longer equal to the energy of the system.


  5. _Cyclic Systems._

  A _cyclic_ or _gyrostatic_ system is characterized by the following
  properties. In the first place, the kinetic energy is not affected if
  we alter the absolute values of certain of the co-ordinates, which we
  will denote by [chi], [chi]', [chi]", ..., provided the remaining
  co-ordinates q1, q2, ... q_m and the velocities, including of course
  the velocities [.[chi]], [.[chi]]', [.[chi]]", ..., are unaltered.
  Secondly, there are no forces acting on the system of the types [chi],
  [chi]', [chi]", .... This case arises, for example, when the system
  includes gyrostats which are free to rotate about their axes, the
  co-ordinates [chi], [chi]', [chi]", ... then being the angular
  co-ordinates of the gyrostats relatively to their frames. Again, in
  theoretical hydrodynamics we have the problem of moving solids in a
  frictionless liquid; the ignored co-ordinates [chi], [chi]', [chi]",
  ... then refer to the fluid, and are infinite in number. The same
  question presents itself in various physical speculations where
  certain phenomena are ascribed to the existence of _latent motions_ in
  the ultimate constituents of matter. The general theory of such
  systems has been treated by E.J. Routh, Lord Kelvin, and H.L.F.
  Helmholtz.


    Routh's equations.

  If we suppose the kinetic energy [Tau] to be expressed, as in
  Lagrange's method, in terms of the co-ordinates and the velocities,
  the equations of motion corresponding to [chi], [chi]', [chi]'´, ...
  reduce, in virtue of the above hypotheses, to the forms

    d  dP[Tau]        d   dP[Tau]       d   dP[Tau]
    -- --------- = 0, -- --------- = 0, -- --------- = 0, ...,  (1)
    dt dP[chi]`       dt dP[chi]`'      dt dP[chi]`"

  whence

     dP[Tau]             dP[Tau]               dP[Tau]
    -------- = [kappa], --------- = [kappa]', --------- = [kappa]", ..., (2)
    dP[chi]`            dP[chi]`'             dP[chi]`"

  where [kappa], [kappa]', [kappa]", ... are the constant momenta
  corresponding to the cyclic co-ordinates [chi], [chi]', [chi]", ....
  These equations are linear in [.[chi]], [.[chi]]', [.[chi]]", ...;
  solving them with respect to these quantities and substituting in the
  remaining Lagrangian equations, we obtain m differential equations to
  determine the remaining co-ordinates q1, q2, ... q_m. The object of
  the present investigation is to ascertain the general form of the
  resulting equations. The retained co-ordinates q1, q2, ... q_m may be
  called (for distinction) the _palpable_ co-ordinates of the system; in
  many practical questions they are the only co-ordinates directly in
  evidence.

  If, as in § 1 (25), we write

    R = [Tau] - [kappa][chi]` - [kappa]'[chi]`' - [kappa]"[chi]`" - ..., (3)

  and imagine R to be expressed by means of (2) as a quadratic function
  of q`1, q`2, ... q`_m, [kappa], [kappa]', [kappa]", ... with
  coefficients which are in general functions of the co-ordinates q1,
  q2, ... q_m, then, performing the operation [delta] on both sides, we
  find

     dPR                       dPR                          dPR                   dP[Tau]                   dP[Tau]
    -----[delta]q`1 + ... + ---------[delta][kappa] + ... + ----[delta]q1 + ... = -------[delta]q`1 + ... + -------[delta]q1 + ...
    dPq`1                   dP[kappa]                       dPq1                   dPq`1                     dPq1

         dP[Tau]                      dP[Tau]
      + --------[delta][chi]` + ... + --------[delta]q1 + ... - [kappa][delta][chi]` - [chi]`[delta][kappa] - .... (4)
        dP[chi]`                      dP[chi]1

  Omitting the terms which cancel by (2), we find

    dP[Tau]    dPR   dP[Tau]    dPR
    ------- = -----, ------- = -----, ...,  (5)
     dPq`1    dPq`1   dPq`2    dPq`2

    dP[Tau]   dPR   dP[Tau]   dPR
    ------- = ----, ------- = ----, ...,  (6)
     dPq1     dPq1   dPq2     dPq2

                    dPR                    dPR                     dPR
    [chi]`  =  - ---------, [chi]`' = - ----------, [chi]`" = - ----------, ... (7)
                 dP[kappa]              dP[kappa]'              dP[kappa]"

  Substituting in § 2 (10), we have

    d   dPR     dPR        d   dPR    dPR
    -- ----- - ----- = Q1, -- ----- - ---- = Q2, ...  (8)
    dt dPq`1   dPq1        dt dPq`2   dPq2

  These are Routh's forms of the modified Lagrangian equations.
  Equivalent forms were obtained independently by Helmholtz at a later
  date.


    Kelvin's equations.

  The function R is made up of three parts, thus

    R = R(2,0) + R(1,1) + R(0,2), ...  (9)

  where R(2,0) is a homogeneous quadratic function of q`1, q`2, ...
  q`_m, R(0,2) is a homogeneous quadratic function of [kappa], [kappa]',
  [kappa]", ..., whilst R(1,1) consists of products of the velocities
  q`1, q`2, ... q`_m into the momenta [kappa], [kappa]', [kappa]"....
  Hence from (3) and (7) we have

                 /           dPR                 dPR                   dPR         \
    [Tau] = R - ( [kappa] --------- + [kappa]'---------- + [kappa]" ---------- + ...)
                 \        dP[kappa]           dP[kappa]'            dP[kappa]"     /

      = R(2,0) - R(0,2).  (10)

  If, as in § 1 (30), we write this in the form

    [Tau] = [@] + [Kappa],  (11)

  then (3) may be written

    R = [@] - [Kappa] + ß1q`1 + ß2q`2 + ...,  (12)

  where ß1, ß2, ... are linear functions of [kappa], [kappa]', [kappa]",
  ..., say

    ß_r = [alpha]_r[kappa] + [alpha]'_r[kappa]' + [alpha]"_r[kappa]" + ..., (13)

  the coefficients [alpha]_r, [alpha]'_r, [alpha]"_r, ... being in
  general functions of the co-ordinates q1, q2, ... q_m. Evidently ß_r
  denotes that part of the momentum-component dPR/dPq`_r which is due to
  the cyclic motions. Now

    d   dPR      d  / dP[@]     \    d   dP[@]   dPß_r      dPß_r
    -- ------ = -- ( ------ + ß_r) = -- ------ + -----q`1 + -----q`2 + ..., (14)
    dt dPq`_r   dt  \dPq`_r     /    dt dPq`_r    dPq1       dPq2

     dPR    dP[@]   dP[Kappa]   dPß1       dPß2
    ----- = ----- - --------- + -----q`1 + -----q`2 + .... (15)
    dPq_r   dPq_r     dPq_r     dPq_r      dPq_r

  Hence, substituting in (8), we obtain the typical equation of motion
  of a gyrostatic system in the form

    d   dP[@]   dP[@]                                                    dP[Kappa]
    -- ------ - ----- + (r, 1)q`1 + (r, 2)q`2 + ... + (r, s)q`_s + ... + --------- = Q_r, (16)
    dt dPq`_r   dPq_r                                                      dPq_r

  where

             dPß_r   dPß_s
    (r, s) = ----- - -----.  (17)
             dPq_s   dPq_r

  This form is due to Lord Kelvin. When q1, q2, ... q_m have been
  determined, as functions of the time, the velocities corresponding to
  the cyclic co-ordinates can be found, if required, from the relations
  (7), which may be written

             dP[Kappa]                                        \
    [Chi]` = --------- - [alpha]1q`1 - [alpha]2q`2 - ...,     |
             dP[kappa]                                        |
                                                              |
              dP[Kappa]                                        >  (18)
    [Chi]`' = ---------- - [alpha]'1q`1 - [alpha]'2q`2 - ..., |
              dP[kappa]'                                      |
                                                              |
       &c., &c.                                               /

  It is to be particularly noticed that

    (r, r) = 0, (r, s) = -(s, r).  (19)

  Hence, if in (16) we put r = 1, 2, 3, ... m, and multiply by q`1,
  q`2, ... q`_m respectively, and add, we find

    d
    --([@] + [Kappa]) = Q1q`1 + Q2q`2 + ...,  (20)
    dt

  or, in the case of a conservative system

    [@] + V + [Kappa] = const.,  (21)

  which is the equation of energy.

  The equation (16) includes § 3 (17) as a particular case, the
  eliminated co-ordinate being the angular co-ordinate of a rotating
  solid having an infinite moment of inertia.

  In the particular case where the cyclic momenta [kappa], [kappa]',
  [kappa]", ... are all zero, (16) reduces to

    d   dP[@]   dP[@]
    -- ------ - ----- = Q_r.  (22)
    dt dPq`_r   dPq_r

  The form is the same as in § 2, and the system now behaves, as regards
  the co-ordinates q1, q2, ... q_m, exactly like the acyclic type there
  contemplated. These co-ordinates do not, however, now fix the position
  of every particle of the system. For example, if by suitable forces
  the system be brought back to its initial configuration (so far as
  this is defined by q1, q2, ..., q_m), after performing any evolutions,
  the ignored co-ordinates [chi], [chi]', [chi]", ... will not in
  general return to their original values.

  If in Lagrange's equations § 2 (10) we reverse the sign of the
  time-element dt, the equations are unaltered. The motion is therefore
  reversible; that is to say, if as the system is passing through any
  configuration its velocities q`1, q`2, ..., q`_m be all
  reversed, it will (if the forces be the same in the same
  configuration) retrace its former path. But it is important to observe
  that the statement does not in general hold of a gyrostatic system;
  the terms of (16), which are linear in q`1, q`2, ..., q`_m,
  change sign with dt, whilst the others do not. Hence the motion of a
  gyrostatic system is not reversible, unless indeed we reverse the
  cyclic motions as well as the velocities q`1, q`2, ..., q`_m.
  For instance, the precessional motion of a top cannot be reversed
  unless we reverse the spin.


    Kinetostatics.

  The _conditions of equilibrium_ of a system with latent cyclic motions
  are obtained by putting q`1 = 0, q`2 = 0, ... q`_m = 0 in (16); viz.
  they are

         dP[Kappa]       dP[Kappa]
    Q1 = ---------, Q2 = ---------, ...  (23)
           dPq1            dPq2

  These may of course be obtained independently. Thus if the system be
  guided from (apparent) rest in the configuration (q1, q2, ... q_m) to
  rest in the configuration q1 + [delta]q1, q2 + [delta]q2, ..., q_m +
  [delta]q_m, the work done by the forces must be equal to the increment
  of the kinetic energy. Hence

    Q1[delta]q1 + Q2[delta]q2 + ... = [delta][Kappa],  (24)

  which is equivalent to (23). The conditions are the same as for the
  equilibrium of a system without latent motion, but endowed with
  potential energy [Kappa]. This is important from a physical point of
  view, as showing how energy which is apparently potential may in its
  ultimate essence be kinetic.

  By means of the formulae (18), which now reduce to

             dP[Kappa]            dP[Kappa]             dP[Kappa]
    [chi]` = ---------, [chi]`' = ----------, [chi]`" = ---------- ..., (25)
             dP[kappa]            dP[kappa]'            dP[kappa]"

  [Kappa] may also be expressed as a homogeneous quadratic function of
  the cyclic velocities [.[chi]], [.[chi]]', [.[chi]]", ... Denoting it
  in this form by [Tau]0, we have

    [delta]([Tau]0 + [Kappa] = 2[delta][Kappa] = [delta]([kappa] [chi]` + [kappa]'[chi]`' + [kappa]"[chi]`" +  ...). (26)

  Performing the variations, and omitting the terms which cancel by (2)
  and (25), we find

    dP[Tau]0     dP[Kappa]  dP[Tau]0     dP[Kappa]
    -------- = - ---------, -------- = - ---------, ...,  (27)
      dPq1         dPq1       dPq2         dPq2

  so that the formulae (23) become

           dP[Tau]0         dP[Tau]0
    Q1 = - --------, Q2 = - --------, ...  (28)
             dPq1             dPq2

  A simple example is furnished by the top (MECHANICS, § 22). The cyclic
  co-ordinates being [psi], [phi], we find

                                  (µ - [nu] cos [theta])²   [nu]²
    2[@] = A[theta]`², 2[Kappa] = ----------------------- + -----,
                                      A sin² [theta]          C

      2[Tau]0 = A sin²[theta][psi]`² + C([phi]` + [psi] cos [theta])², (29)

  whence we may verify that dP[Tau]0/dP[theta] = - dP[Kappa]/dP[theta]
  in accordance with (27). And the condition of equilibrium

    dP[Kappa]        dPV
    --------- = - ---------  (30)
    dP[theta]     dP[theta]

  gives the condition of steady precession.


  6. _Stability of Steady Motion._

  The small oscillations of a conservative system about a configuration
  of equilibrium, and the criterion of stability, are discussed in
  MECHANICS, § 23. The question of the stability of given types of
  motion is more difficult, owing to the want of a sufficiently general,
  and at the same time precise, definition of what we mean by
  "stability." A number of definitions which have been propounded by
  different writers are examined by F. Klein and A. Sommerfeld in their
  work _Über die Theorie des Kreisels_ (1897-1903). Rejecting previous
  definitions, they base their criterion of stability on the character
  of the changes produced in the _path_ of the system by small arbitrary
  disturbing impulses. If the undisturbed path be the _limiting form_ of
  the disturbed path when the impulses are indefinitely diminished, it
  is said to be stable, but not otherwise. For instance, the vertical
  fall of a particle under gravity is reckoned as stable, although for a
  _given_ impulsive disturbance, however small, the deviation of the
  particle's position at any time t from the position which it would
  have occupied in the original motion increases indefinitely with t.
  Even this criterion, as the writers quoted themselves recognize, is
  not free from ambiguity unless the phrase "limiting form," as applied
  to a path, be strictly defined. It appears, moreover, that a
  definition which is analytically precise may not in all cases be easy
  to reconcile with geometrical prepossessions. Thus a particle moving
  in a circle about a centre of force varying inversely as the cube of
  the distance will if slightly disturbed either fall into the centre,
  or recede to infinity, after describing in either case a spiral with
  an infinite number of convolutions. Each of these spirals has,
  analytically, the circle as its limiting form, although the motion in
  the circle is most naturally described as unstable.

  A special form of the problem, of great interest, presents itself in
  the steady motion of a gyrostatic system, when the non-eliminated
  co-ordinates q1, q2, ... q_m all vanish (see § 5). This has been
  discussed by Routh, Lord Kelvin and Tait, and Poincaré. These writers
  treat the question, by an extension of Lagrange's method, as a problem
  of small oscillations. Whether we adopt the notion of stability which
  this implies, or take up the position of Klein and Sommerfeld, there
  is no difficulty in showing that stability is ensured if V + [Kappa]
  be a minimum as regards variations of q1, q2, ... q_m. The proof is
  the same as that of Dirichlet for the case of statical stability.

  We can illustrate this condition from the case of the top, where, in
  our previous notation,

                                   (µ - [nu]cos [theta])²   [nu]²
    V + [Kappa] = Mgh cos[theta] + ---------------------- + -----. (1)
                                       2A sin² [theta]       2C

  To examine whether the steady motion with the centre of gravity
  vertically above the pivot is stable, we must put µ = [nu]. We then
  find without difficulty that V + [Kappa] is a minimum provided [nu]²
  [>=] 4AMgh. The method of small oscillations gave us the condition
  [nu]² > 4AMgh, and indicated instability in the cases [nu]² [=<]
  4AMgh. The present criterion can also be applied to show that the
  steady precessional motions in which the axis has a constant
  inclination to the vertical are stable.

  The question remains, as before, whether it is _essential_ for
  stability that V + [Kappa] should be a minimum. It appears that from
  the point of view of the theory of small oscillations it is not
  essential, and that there may even be stability when V + [Kappa] is a
  maximum. The precise conditions, which are of a somewhat elaborate
  character, have been formulated by Routh. An important distinction
  has, however, been established by Thomson and Tait, and by Poincaré,
  between what we may call _ordinary_ or _temporary_ stability (which is
  stability in the above sense) and _permanent_ or _secular_ stability,
  which means stability when regard is had to possible dissipative
  forces called into play whenever the co-ordinates q1, q2, ... q_m
  vary. Since the total energy of the system at any instant is given (in
  the notation of § 5) by an expression of the form [@] + V +
  [Kappa], where [@] cannot be negative, the argument of Thomson
  and Tait, given under MECHANICS, § 23, for the statical question,
  shows that it is a necessary as well as a sufficient condition for
  secular stability that V + [Kappa] should be a minimum. When a system
  is "ordinarily" stable, but "secularly" unstable, the operation of the
  frictional forces is to induce a gradual increase in the amplitude of
  the free vibrations which are called into play by accidental
  disturbances.

  There is a similar theory in relation to the constrained systems
  considered in § 3 above. The equation (21) there given leads to the
  conclusion that for secular stability of any type of motion in which
  the velocities q`1, q`2, ... q`_n are zero it is necessary and
  sufficient that the function V - [Tau]0 should be a minimum.

  The simplest possible example of this is the case of a particle at the
  lowest point of a smooth spherical bowl which rotates with constant
  angular velocity ([omega]) about the vertical diameter. This position
  obviously possesses "ordinary" stability. If a be the radius of the
  bowl, and [theta] denote angular distance from the lowest point, we
  have

    V - [Tau]0 = mga(1 - cos [theta]) - ½m[omega]²a² sin² [theta];  (2)

  this is a minimum for [theta] = 0 only so long as [omega]² < g/a. For
  greater values of [omega] the only position of "permanent" stability
  is that in which the particle rotates with the bowl at an angular
  distance cos^(-1) (g/[omega]²a) from the lowest point. To examine the
  motion in the neighbourhood of the lowest point, when frictional
  forces are taken into account, we may take fixed ones, in a horizontal
  plane, through the lowest point. Assuming that the friction varies as
  the relative velocity, we have

    x¨ = -p²x - k(x` + [omega]y),  \  (3)
    y¨ = -p²y - k(y` - [omega]x),  /

  where p² = g/a. These combine into

    z¨ + kz` + (p² - ik[omega])z = 0,  (4)

  where z = x + iy, i = [root]-1. Assuming z = Ce^([lambda]t), we find

    [lambda] = -½k(1 [-+] [omega]/p) ± ip,  (5)

  if the square of k be neglected. The complete solution is then

    x + iy = C1e^(-ß1t)e^(ipt) + C2e^(-ß2t)e^(-ipt),  (6)

  where ß1 = ½k(1 - [omega]/p), ß2 = ½k(1 + [omega]/p). (7)

  This represents two superposed circular vibrations, in opposite
  directions, of period 2[pi]/p. If [omega] < p, the amplitude of each
  of these diminishes asymptotically to zero, and the position x = 0, y
  = 0 is permanently stable. But if [omega] > p the amplitude of that
  circular vibration which agrees in sense with the rotation [omega]
  will continually increase, and the particle will work its way in an
  ever-widening spiral path towards the eccentric position of secular
  stability. If the bowl be not spherical but ellipsoidal, the vertical
  diameter being a principal axis, it may easily be shown that the
  lowest position is permanently stable only so long as the period of
  the rotation is longer than that of the slower of the two normal
  modes in the absence of rotation (see MECHANICS, § 13).


  7. _Principle of Least Action._

    Stationary Action.

  The preceding theories give us statements applicable to the system at
  any one instant of its motion. We now come to a series of theorems
  relating to the whole motion of the system between any two
  configurations through which it passes, viz. we consider the actual
  motion and compare it with other imaginable motions, differing
  infinitely little from it, between the same two configurations. We use
  the symbol [delta] to denote the transition from the actual to any one
  of the hypothetical motions.

  The best-known theorem of this class is that of _Least Action_,
  originated by P.L.M. de Maupertuis, but first put in a definite form
  by Lagrange. The "action" of a single particle in passing from one
  position to another is the space-integral of the momentum, or the
  time-integral of the _vis viva_. The action of a dynamical system is
  the sum of the actions of its constituent particles, and is
  accordingly given by the formula
                 _                _            _
                /                /            /
    A = [Sigma] | mvds = [Sigma] |  mv²dt = 2 | [Tau]dt.  (1)
               _/               _/           _/

  The theorem referred to asserts that the free motion of a conservative
  system between any two given configurations is characterized by the
  property

    [delta]A = 0,  (2)

  provided the total energy have the same constant value in the varied
  motion as in the actual motion.

  If t, t' be the times of passing through the initial and final
  configurations respectively, we have
                        _
                       / t'
    [delta]A = [delta] |  [Sigma]m(x`² + y`² + z`²)dt
                      _/t
                _
               / t'
           = 2 |  [delta][Tau]dt + 2[Tau]'[delta]t' + 2[Tau][delta]t, (3)
              _/t

  since the upper and lower limits of the integral must both be regarded
  as variable. This may be written
                _                   _
               / t'                / t'
    [delta]A = |  [delta][Tau]dt + |  [Sigma]m(x`[delta]x` + y`[delta]y` + z`[delta]z`)dt + 2[Tau]'[delta]t' - 2[Tau][delta]t
              _/t                 _/t
         _                   _                                              _
        / t'                |                                                | t'
      = |  [delta][Tau]dt + | [Sigma]m (x`[delta]x + y`[delta]y + z`[delta]z |
       _/t                  |_                                              _| t
           _
          / t'
        - |  [Sigma]m(x¨[delta]x + y¨[delta]y + z¨[delta]z)dt + 2[Tau]'[delta]t' - 2[Tau][delta]t. (4)
         _/t

  Now, by d'Alembert's principle,

    [Sigma]m( x¨[delta]x + y¨[delta]y + z¨[delta]z ) = -[delta]V,  (5)

  and by hypothesis we have

    [delta]([Tau] + V) = 0.  (6)

  The formula therefore reduces to
                _                                               _
               |                                                 |t'
    [delta]A = | [Sigma]m (x`[delta]x + y`[delta]y + z`[delta]z) | + 2[Tau]'[delta]t' - 2[Tau][delta]t. (7)
               |_                                               _|t

  Since the terminal configurations are unaltered, we must have at the
  lower limit

    [delta]x + x`[delta]t = 0, [delta]y + y`[delta]t = 0, [delta]z + z`[delta]t = 0, (8)

  with similar relations at the upper limit. These reduce (7) to the
  form (2).

  The equation (2), it is to be noticed, merely expresses that the
  variation of A vanishes _to the first order_; the phrase _stationary
  action_ has therefore been suggested as indicating more accurately
  what has been proved. The action in the free path between two given
  configurations is in fact not invariably a minimum, and even when a
  minimum it need not be the _least possible_ subject to the given
  conditions. Simple illustrations are furnished by the case of a single
  particle. A particle moving on a smooth surface, and free from
  extraneous force, will have its velocity constant; hence the theorem
  in this case resolves itself into
             _
            /
    [delta] | ds = 0,  (9)
           _/

  i.e. the path must be a geodesic line. Now a geodesic is not
  necessarily the _shortest_ path between two given points on it; for
  example, on the sphere a great-circle arc ceases to be the shortest
  path between its extremities when it exceeds 180°. More generally,
  taking any surface, let a point P, starting from O, move along a
  geodesic; this geodesic will be a minimum path from O to P until P
  passes through a point O' (if such exist), which is the intersection
  with a consecutive geodesic through O. After this point the minimum
  property ceases. On an anticlastic surface two geodesics cannot
  intersect more than once, and each geodesic is therefore a minimum
  path between any two of its points. These illustrations are due to
  K.G.J. Jacobi, who has also formulated the general criterion,
  applicable to all dynamical systems, as follows:--Let O and P denote
  any two configurations on a natural path of the system. If this be the
  sole free path from O to P with the prescribed amount of energy, the
  action from O to P is a minimum. But if there be several distinct
  paths, let P vary from coincidence with O along the first-named path;
  the action will then cease to be a minimum when a configuration O' is
  reached such that two of the possible paths from O to O' coincide. For
  instance, if O and P be positions on the parabolic path of a
  projectile under gravity, there will be a second path (with the same
  energy and therefore the same velocity of projection from O), these
  two paths coinciding when P is at the other extremity (O', say) of the
  focal chord through O. The action from O to P will therefore be a
  minimum for all positions of P short of O'. Two configurations such as
  O and O' in the general statement are called conjugate _kinetic foci_.
  Cf. VARIATIONS, CALCULUS OF.

  Before leaving this topic the connexion of the principle of stationary
  action with a well-known theorem of optics may be noticed. For the
  motion of a particle in a conservative field of force the principle
  takes the form
             _
            /
    [delta] | vds = 0.  (10)
           _/

  On the corpuscular theory of light v is proportional to the refractive
  index µ of the medium, whence
             _
            /
    [delta] | µds = 0.  (11)
           _/


    Hamiltonian principle.

  In the formula (2) the energy in the hypothetical motion is
  prescribed, whilst the time of transit from the initial to the final
  configuration is variable. In another and generally more convenient
  theorem, due to Hamilton, the time of transit is prescribed to be the
  same as in the actual motion, whilst the energy may be different and
  need not (indeed) be constant. Under these conditions we have
             _
            /t'
    [delta] | ([Tau] - V)dt = 0,  (12)
           _/t

  where t, t' are the prescribed times of passing through the given
  initial and final configurations. The proof of (12) is simple; we have
             _                 _                               _
            /t'               /t'                             /t'
    [delta] | ([Tau] - V)dt = | ([delta][Tau] - [delta]V)dt = |  {[Sigma]m(x`[delta]x` + y`[delta]y` + z`[delta]z`) - [delta]V}dt
           _/t               _/t                             _/t
         _                                              _
        |                                                |t'
      = | [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) |
        |_                                              _|t
       _
      /t'
    - | {[Sigma]m(x¨[delta]x + y¨[delta]y + z¨[delta]z) + [delta]V}dt (13)
     _/t

  The integrated terms vanish at both limits, since by hypothesis the
  configurations at these instants are fixed; and the terms under the
  integral sign vanish by d'Alembert's principle.

  The fact that in (12) the variation does not affect the time of
  transit renders the formula easy of application in any system of
  co-ordinates. Thus, to deduce Lagrange's equations, we have

      _                             _
     /t'                           /t'/dP[Tau]             dP[Tau]                  dPV               \
     | ([delta][Tau]-[delta]V)dt = | ( -------[delta]q`1 + -------[delta]q1 + ... - ----[delta]q1 - ...)dt
    _/t                           _/t \ dPq`1               dPq1                    dPq1              /
         _                               _
        |                                 |t'
      = | p1[delta]q1 + p2[delta]q2 + ... |
        |_                               _|t

       _  _                                                                        _
      /t'|  /     dP[Tau]   dPV \              /     dP[Tau]    dPV\                |
    - |  | (p`1 - ------- + ---- )[delta]q1 + (p`2 - ------- + -----)[delta]q2 + ...|dt. (14)
     _/t |_ \      dPq1     dPq1/              \      dPq2     dPq2/               _|

  The integrated terms vanish at both limits; and in order that the
  remainder of the right-hand member may vanish it is necessary that the
  coefficients of [delta]q1, [delta]q2, ... under the integral sign
  should vanish for all values of t, since the variations in question
  are independent, and subject only to the condition of vanishing at the
  limits of integration. We are thus led to Lagrange's equation of
  motion for a conservative system. It appears that the formula (12) is
  a convenient as well as a compact embodiment of the whole of ordinary
  dynamics.


    Extension to cyclic systems.

  The modification of the Hamiltonian principle appropriate to the case
  of cyclic systems has been given by J. Larmor. If we write, as in § 1
  (25),

    R = T - [kappa][chi]` - [kappa]'[chi]`' - [kappa]'´[chi]`" - ..., (15)

  we shall have
             _
            /t'
    [delta] | (R - V)dt = 0,  (16)
           _/t

  provided that the variation does not affect the cyclic momenta
  [kappa], [kappa]', [kappa]", ..., and that the configurations at times
  t and t' are unaltered, so far as they depend on the palpable
  co-ordinates q1, q2, ... q_m. The initial and final values of the
  ignored co-ordinates will in general be affected.

  To prove (16) we have, on the above understandings,
             _             _
            /t'           /t'
    [delta] | (R - V)dt = | ([delta][Tau] - [kappa][delta][chi]` - ... -[delta]V)dt
           _/t           _/t
         _
        /t' /dP[Tau]                   dP[Tau]                          \
      = |  ( -------[delta]q`1 + ... + -------[delta]q1 + ... - [delta]V )dt,  (17)
       _/t  \ dPq`1                     dPq1                            /

  where terms have been cancelled in virtue of § 5 (2). The last member
  of (17) represents a variation of the integral
      _
     /t'
     | ([Tau] - V)dt
    _/t

  on the supposition that [delta]X = 0, [delta]X' = 0, [delta]X" = 0,
  ... throughout, whilst [delta]q1, [delta]q2, [delta]q_m vanish at
  times t and t'; i.e. it is a variation in which the initial and final
  configurations are absolutely unaltered. It therefore vanishes as a
  consequence of the Hamiltonian principle in its original form.

  Larmor has also given the corresponding form of the principle of least
  action. He shows that if we write
         _
        /
    A = |(2[Tau] - [kappa][chi]` - [kappa]'[chi]`' - [kappa]"[chi]`" - ...)dt, (18)
       _/

  then

    [delta]A = 0,  (19)

  provided the varied motion takes place with the same constant value of
  the energy, and with the same constant cyclic momenta, between the
  same two configurations, these being regarded as defined by the
  palpable co-ordinates alone.


  § 8. _Hamilton's Principal and Characteristic Functions._

    Principal function.

  In the investigations next to be described a more extended meaning is
  given to the symbol [delta]. We will, in the first instance, denote by
  it an infinitesimal variation of the most general kind, affecting not
  merely the values of the co-ordinates at any instant, but also the
  initial and final configurations and the times of passing through
  them. If we put
         _
        /t'
    S = | (T - V)dt,  (1)
       _/t

  we have, then,
                                                       _
                                                      /t'
    [delta]S = (T' - V')[delta]t' - (T - V)[delta]t + | ([delta]T - [delta]V)dt
                                                     _/t
                                                _                                            _
                                               |                                              |t'
      = (T' - V')[delta]t' - (T - V)[delta]t + |[Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z)|  (2)
                                               |_                                            _|t

  Let us now denote by x' + [delta]x', y' + [delta]y', z' + [delta]z',
  the final co-ordinates (i.e. at time t' + [delta]t') of a particle m.
  In the terms in (2) which relate to the upper limit we must therefore
  write [delta]x' - x`'[delta]t', [delta]y' - y`'[delta]t',
  [delta]z' - z`'[delta]t' for [delta]x, [delta]y, [delta]z. With a
  similar modification at the lower limit, we obtain

    [delta]S = - H[delta][tau] + [Sigma]m(x`'[delta]x' + y`'[delta]y' + z`'[delta]z')
      - [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z),  (3)

  where H(= T + V) is the constant value of the energy in the free
  motion of the system, and [tau](= t' - t) is the time of transit. In
  generalized co-ordinates this takes the form

    [delta]S = - H[delta][tau] + p'1[delta]q'1 + p'2[delta]q'2 + ...
      - p1[delta]q1 - p2[delta]q2 - ....  (4)

  Now if we select any two arbitrary configurations as initial and
  final, it is evident that we can in general (by suitable initial
  velocities or impulses) start the system so that it will of itself
  pass from the first to the second in any prescribed time [tau]. On
  this view of the matter, S will be a function of the initial and final
  co-ordinates (q1, q2, ... and q'1, q'2, ...) and the time [tau], as
  independent variables. And we obtain at once from (4)

           dPS          dPS        \
    p'1 = -----, p'2 = -----, ..., |
          dPq'1        dPq'2       |
                                    >  (5)
           dPS          dPS        |
    p1 = - ----, p2 = - ----, ..., |
           dPq1         dPq2       /

              dPS
  and H = - -------.                            (6)
            dP[tau]

  S is called by Hamilton the _principal function_; if its general form
  for any system can be found, the preceding equations suffice to
  determine the motion resulting from any given conditions. If we
  substitute the values of p1, p2, ... and H from (5) and (6) in the
  expression for the kinetic energy in the form [Tau]' (see § 1), the
  equation

    T¹ + V = H  (7)

  becomes a partial differential equation to be satisfied by S. It has
  been shown by Jacobi that the dynamical problem resolves itself into
  obtaining a "complete" solution of this equation, involving n + 1
  arbitrary constants. This aspect of the subject, as a problem in
  partial differential equations, has received great attention at the
  hands of mathematicians, but must be passed over here.


    Characteristic function.

  There is a similar theory for the function
           _
          /
    A = 2 | Tdt = S + H[tau]  (8)
         _/

  It follows from (4) that

    [delta]A = [tau][delta]H + p'1[delta]q'1 + p'2[delta]q'2 + ...
      - p1[delta]q1 - p2[delta]q2 - ....  (9)

  This formula (it may be remarked) contains the principle of "least
  action" as a particular case. Selecting, as before, any two arbitrary
  configurations, it is in general possible to start the system from one
  of these, with a prescribed value of the total energy H, so that it
  shall pass through the other. Hence, regarding A as a function of the
  initial and final co-ordinates and the energy, we find

           dPA          dPA        \
    p'1 = -----, p'2 = -----, ..., |
          dPq'1        dPq'2       |
                                    >  (10)
           dPA          dPA        |
    p1 = - ----, p2 = - ----, ..., |
           dPq1         dPq2       /

              dPA
  and [tau] = ---   (11)
              dPH

  A is called by Hamilton the _characteristic function_; it represents,
  of course, the "action" of the system in the free motion (with
  prescribed energy) between the two configurations. Like S, it
  satisfies a partial differential equation, obtained by substitution
  from (10) in (7).

  The preceding theorems are easily adapted to the case of cyclic
  systems. We have only to write
         _            _
        /t'          /t'
    S = | (R - V)dt= | (T - [kappa][chi]` - [kappa]'[chi]`' - ... - V)dt (12)
       _/t          _/t

  in place of (1), and
         _
        /
    A = | (2T - [kappa][chi]` - [kappa]'[chi]`' - ...)dt,  (3)
       _/

  in place of (8); cf. § 7 ad fin. It is understood, of course, that in
  (12) S is regarded as a function of the initial and final values of
  the palpable co-ordinates q1, q2, ... q_m, and of the time of transit
  [tau], the cyclic momenta being invariable. Similarly in (13), A is
  regarded as a function of the initial and final values of q1, q2, ...
  q_m, and of the total energy H, with the cyclic momenta invariable. It
  will be found that the forms of (4) and (9) will be conserved,
  provided the variations [delta]q1, [delta]q2, ... be understood to
  refer to the palpable co-ordinates alone. It follows that the
  equations (5), (6) and (10), (11) will still hold under the new
  meanings of the symbols.


  9. _Reciprocal Properties of Direct and Reversed Motions._

    Lagrange's formula.

  We may employ Hamilton's principal function to prove a very remarkable
  formula connecting any _two_ slightly disturbed natural motions of the
  system. If we use the symbols [delta] and [Delta] to denote the
  corresponding variations, the theorem is

    d
    --[Sigma]([delta]p_r·[Delta]q_r - [Delta]p_r·[delta]q_r) = 0;  (1)
    dt

  or integrating from t to t',

    [Sigma]([delta]p'_r·[Delta]q'_r - [Delta]q'_r·[delta]q'_r) = [Sigma]([delta]p_r·[Delta]q_r - [Delta]p_r·[delta]q_r). (2)

  If for shortness we write

               dP²S                 dP²S
    (r,s) = ----------, (r,s') = -----------,  (3)
            dPq_rdPq_s           dPq_rdPq'_s

  we have

    dPp_r = - [Sigma]_s(r,s)[delta]q_s - [Sigma]_s(r,s')[delta]q'_s  (4)

  with a similar expression for [Delta]p_r. Hence the right-hand side of
  (2) becomes

    - [Sigma]_r{[Sigma]_s(r,s)[delta]q_s + [Sigma]_s(r,s')[delta]q'_s}[Delta]q_r
      + [Sigma]_r{[Sigma]_s(r,s)[Delta]q_s + [Sigma]_s(r,s')[Delta]q'_s}[delta]q_r
        = [Sigma]_r[Sigma]_s(r,s'){[delta]q_r·[Delta]q'_s - [Delta]q_r·[delta]q'_s}. (5)

  The same value is obtained in like manner for the expression on the
  left hand of (2); hence the theorem, which, in the form (1), is due to
  Lagrange, and was employed by him as the basis of his method of
  treating the dynamical theory of _Variation of Arbitrary Constants_.


    Helmholtz's reciprocal theorems.

  The formula (2) leads at once to some remarkable reciprocal relations
  which were first expressed, in their complete form, by Helmholtz.
  Consider any natural motion of a conservative system between two
  configurations O and O' through which it passes at times t and t'
  respectively, and let t' - t = [tau]. As the system is passing through
  O let a small impulse [delta]p_r be given to it, and let the
  consequent alteration in the co-ordinate q_s after the time [tau] be
  [delta]q'_s. Next consider the _reversed_ motion of the system, in
  which it would, if undisturbed, pass from O' to O in the same time
  [tau]. Let a small impulse [delta]p'_s be applied as the system is
  passing through O', and let the consequent change in the co-ordinate
  q_r after a time [tau] be [delta]q_r. Helmholtz's first theorem is to
  the effect that

    [delta]q_r : [delta]p'_s = [delta]q'_s : [delta]p_r.  (6)

  To prove this, suppose, in (2), that all the [delta]q vanish, and
  likewise all the [delta]p with the exception of [delta]p_r. Further,
  suppose all the [Delta]q' to vanish, and likewise all the [Delta]p'
  except [Delta]p'_s, the formula then gives

    [delta]p_r·[Delta]q_r = - [Delta]p'_s·[delta]q'_s,  (7)

  which is equivalent to Helmholtz's result, since we may suppose the
  symbol [Delta] to refer to the reversed motion, provided we change
  the signs of the [Delta]p. In the most general motion of a top
  (MECHANICS, § 22), suppose that a small impulsive couple about the
  vertical produces after a time [tau] a change [delta][theta] in the
  inclination of the axis, the theorem asserts that in the reversed
  motion an equal impulsive couple in the plane of [theta] will produce
  after a time [tau] a change [delta][psi], in the azimuth of the axis,
  which is equal to [delta][theta]. It is understood, of course, that
  the couples have no components (in the generalized sense) except of
  the types indicated; for instance, they may consist in each case of a
  force applied to the top at a point of the axis, and of the
  accompanying reaction at the pivot. Again, in the corpuscular theory
  of light let O, O' be any two points on the axis of a symmetrical
  optical combination, and let V, V' be the corresponding velocities of
  light. At O let a small impulse be applied perpendicular to the axis
  so as to produce an angular deflection [delta][theta], and let ß'
  be the corresponding lateral deviation at O'. In like manner in the
  reversed motion, let a small deflection [delta][theta]' at O' produce
  a lateral deviation ß at O. The theorem (6) asserts that

            ß                  ß'
    ----------------- = ---------------,  (8)
    V'[delta][theta]'   V[delta][theta]

  or, in optical language, the "apparent distance" of O from O' is to
  that of O' from O in the ratio of the refractive indices at O' and O
  respectively.


    Helmholtz's second reciprocal theorem.

  In the second reciprocal theorem of Helmholtz the configuration O is
  slightly varied by a change [delta]q_r in one of the co-ordinates, the
  momenta being all unaltered, and [delta]q'_s is the consequent
  variation in one of the momenta after time [tau]. Similarly in the
  reversed motion a change [delta]p'_s produces after time [tau] a
  change of momentum [delta]p_r. The theorem asserts that

    [delta]p'_s : [delta]q_r = [delta]p_r : [delta]q'_s  (9)

  This follows at once from (2) if we imagine all the [delta]p to
  vanish, and likewise all the [delta]q save [delta]q_r, and if
  (further) we imagine all the [Delta]p' to vanish, and all the
  [Delta]q' save [Delta]q'_s. Reverting to the optical illustration, if
  F, F', be principal foci, we can infer that the convergence at F' of a
  parallel beam from F is to the convergence at F of a parallel beam
  from F' in the inverse ratio of the refractive indices at F' and F.
  This is equivalent to Gauss's relation between the two principal focal
  lengths of an optical instrument. It may be obtained otherwise as a
  particular case of (8).

  We have by no means exhausted the inferences to be drawn from
  Lagrange's formula. It may be noted that (6) includes as particular
  cases various important reciprocal relations in optics and acoustics
  formulated by R.J.E. Clausius, Helmholtz, Thomson (Lord Kelvin) and
  Tait, and Lord Rayleigh. In applying the theorem care must be taken
  that in the reversed motion the reversal is complete, and extends to
  every velocity in the system; in particular, in a cyclic system the
  cyclic motions must be imagined to be reversed with the rest.
  Conspicuous instances of the failure of the theorem through incomplete
  reversal are afforded by the propagation of sound in a wind and the
  propagation of light in a magnetic medium.

  It may be worth while to point out, however, that there is no such
  limitation to the use of Lagrange's formula (1). In applying it to
  cyclic systems, it is convenient to introduce conditions already laid
  down, viz. that the co-ordinates q_r are the palpable co-ordinates and
  that the cyclic momenta are invariable. Special inference can then be
  drawn as before, but the interpretation cannot be expressed so neatly
  owing to the non-reversibility of the motion.

  AUTHORITIES.--The most important and most accessible early authorities
  are J.L. Lagrange, _Mécanique analytique_ (1st ed. Paris, 1788, 2nd
  ed. Paris, 1811; reprinted in _Oeuvres_, vols. xi., xii., Paris,
  1888-89); Hamilton, "On a General Method in Dynamics," _Phil. Trans._
  1834 and 1835; C.G.J. Jacobi, _Vorlesungen über Dynamik_ (Berlin,
  1866, reprinted in _Werke_, Supp.-Bd., Berlin, 1884). An account of
  the extensive literature on the differential equations of dynamics and
  on the theory of variation of parameters is given by A. Cayley,
  "Report on Theoretical Dynamics," _Brit. Assn. Rep._ (1857),
  _Mathematical Papers_, vol. iii. (Cambridge, 1890). For the modern
  developments reference may be made to Thomson and Tait, _Natural
  Philosophy_ (1st ed. Oxford, 1867, 2nd ed. Cambridge, 1879); Lord
  Rayleigh, _Theory of Sound_, vol. i. (1st ed. London, 1877; 2nd ed.
  London, 1894); E.J. Routh, _Stability of Motion_ (London, 1877), and
  _Rigid Dynamics_ (4th ed. London, 1884); H. Helmholtz, "Über die
  physikalische Bedeutung des Prinzips der kleinsten Action," _Crelle_,
  vol. c., 1886, reprinted (with other cognate papers) in _Wiss. Abh._
  vol. iii. (Leipzig, 1895); J. Larmor, "On Least Action," _Proc. Lond.
  Math. Soc._ vol. xv. (1884); E.T. Whittaker, _Analytical Dynamics_
  (Cambridge, 1904). As to the question of stability, reference may be
  made to H. Poincaré, "Sur l'équilibre d'une masse fluide animée d'un
  mouvement de rotation" _Acta math._ vol. vii. (1885); F. Klein and A.
  Sommerfeld, _Theorie des Kreisels_, pts. 1, 2 (Leipzig, 1897-1898); A.
  Lioupanoff and J. Hadamard, _Liouville_, 5me série, vol. iii. (1897);
  T.J.I. Bromwich, Proc. Lond. Math. Soc. vol. xxxiii. (1901). A
  remarkable interpretation of various dynamical principles is given by
  H. Hertz in his posthumous work _Die Prinzipien der Mechanik_
  (Leipzig, 1894), of which an English translation appeared in 1900.
       (H. Lb.)



DYNAMITE (Gr. [Greek: dynamis], power), the name given to several
explosive preparations containing nitroglycerin (q.v.) which are almost
exclusively used for blasting purposes. The first practical application
of nitroglycerin in this way was made by A. Nobel in 1863. He soaked
gunpowder with the liquid and fired the gunpowder by an ordinary fuse.
Later he found that nitroglycerin could be detonated by the explosion of
several materials such as fulminate of mercury, the use of which as a
detonator he patented in 1867. In 1866-1867 he experimented with
charcoal and other substances, and found the infusorial earth known as
kieselguhr, which consists mainly of silica (nearly 95%), eminently
adapted to the purpose, as it was inert, non-combustible, and after a
little heating and preparation very porous, retaining a large amount of
nitroglycerin as water is held in a sponge, without very serious
exudation on standing. This kieselguhr dynamite is generally made by
incorporating three parts of nitroglycerin with one part of the dry
earth, the paste being then formed into cylindrical cartridges. This
work is done by hand. Generally a small percentage of the kieselguhr is
replaced by a mixture containing sodium and ammonium carbonates, talc
and ochre. This product is known as dynamite No. 1. Disabilities
attaching to kieselguhr dynamite are that when placed in water the
nitroglycerin is liable to be exuded or displaced, also that, like
nitroglycerin itself, it freezes fairly easily and thawing the frozen
cartridges is a dangerous operation. Other substances, e.g. kaolin,
tripoli, magnesia alba (magnesium carbonate), alumina, sugar, charcoal,
some powdered salts and mixtures of sawdust and salts, have been shown
to be absorbents more or less adapted to the purpose of making a
dynamite. Charcoal from cork is said to absorb about 90% of its weight
of nitroglycerin. With the idea of obtaining greater safety, mixtures
have been made of nitroglycerin with wood fibre, charcoal and metallic
nitrates. Lithofracteur, for instance, consists of 50% nitroglycerin and
a mixture of prepared sawdust, kieselguhr and barium nitrate. Carbonite
contains 25% of nitroglycerin, the remainder being a mixture of
wood-meal and alkali nitrates, with about 1% of sulphur. Dualin, atlas
dynamite and potentite are other modifications.

A convenient form in which nitroglycerin can be made up for blasting
purposes, especially in wet ground, is the gelatinous material obtained
by the action of nitroglycerin, either alone or with the help of
solvents, on low-grade or soluble gun-cottons. It is known as blasting
gelatin, and was first made by Nobel by incorporating 6 or 7% of low
nitrated cellulose (collodion cotton or soluble gun-cotton) with
slightly warmed nitroglycerin. The result is a transparent plastic
material, of specific gravity 1.5 to 1.6, which may be kept under water
for a long time without appreciable change. It is less sensitive to
detonation than ordinary dynamite, and although its explosion is
slightly slower it is more powerful than dynamite and much superior to
the liquid nitroglycerin. Blasting gelatin also freezes and is sensitive
to percussion in this state. Camphor and other substances have been
added to blasting gelatin to render it more solid and less sensitive.
Some modifications of blasting gelatin, e.g. gelignite, contain
wood-meal and such oxygen-containing salts as potassium nitrate.
Experience has conclusively shown that dynamites are more satisfactory,
quicker, and more intense in action than liquid nitroglycerin.

To prevent nitroglycerin and some of the forms of dynamite from freezing
it has been proposed to add to them small quantities of either
monochlor-dinitroglycerin or of a nitrated poly-glycerin. The former is
obtained by first acting upon glycerin with hydrogen chloride to produce
_u-_chlorhydrin or chlor-propylene glycol, C3H7O2Cl, which is then
nitrated as in the case of glycerin. The latter is obtained by heating
glycerin for six or seven hours to about 300° C., whereby water is split
off in such manner that a diglycerin C6H14O5, for the most part,
results. This on nitration in the usual manner gives a product
C6H{10}N4O{13}, which burns and explodes in a similar manner to ordinary
nitroglycerin, but is less sensitive and does not so easily freeze. The
mono- and di-nitrates of glycerin have also been proposed as additions
to ordinary nitroglycerin (q.v.) for the same purpose.     (W. R. E. H.)



DYNAMO (a shortened form of "dynamo-electric machine," from Gr. [Greek:
dynamis], power), a machine for converting mechanical into electrical
energy.

The dynamo ranks with the telegraph and telephone as one of the three
striking applications of electrical and magnetic science to which the
material progress that marked the second half of the 19th century was in
no small measure due. Since the discovery of the principle of the dynamo
by Faraday in 1831 the simple model which he first constructed has been
gradually developed into the machines of 5000 horse-power or more which
are now built to meet the needs of large cities for electric lighting
and power, while at the same time the numbers of dynamos in use have
increased almost beyond estimate. Yet such was the insight of Faraday
into the fundamental nature of the dynamo that the theory of its action
which he laid down has remained essentially unchanged. His experiments
on the current which was set up in a coil of wire during its movement
across the poles of a magnet led naturally to the explanation of induced
electromotive force as caused by the linking or unlinking of magnetic
lines of flux with an electric circuit. For the more definite case of
the dynamo, however, we may, with Faraday, make the transition from
line-linkage to the equivalent conception of "line-cutting" as the
source of E.M.F.--in other words, to the idea of electric conductors
"cutting" or intersecting[1] the lines of flux in virtue of relative
motion of the magnetic field and electric circuit. On the 28th of
October 1831 Faraday mounted a copper disk so that it could be rotated
edgewise between the poles of a permanent horse-shoe magnet. When so
rotated, it cut the lines of flux which passed transversely through its
lower half, and by means of two rubbing contacts, one on its periphery
and the other on its spindle, the circuit was closed through a
galvanometer, which indicated the passage of a continuous current so
long as the disk was rotated (fig. 1). Thus by the invention of the
first dynamo Faraday proved his idea that the E.M.F. induced through the
interaction of a magnetic field and an electric circuit was due to the
passage of a portion of the electric circuit _across_ the lines of flux,
or vice versa, and so could be maintained if the cutting of the lines
were made continuous.[2] In comparison with Faraday's results, the
subsequent advance is to be regarded as a progressive perfecting of the
mechanical and electro-magnetic design, partly from the theoretical and
partly from the practical side, rather than as modifying or adding to
the idea which was originally present in his mind, and of which he
already saw the possibilities.

[Illustration: FIG. 1.]

A dynamo, then, is a machine in which, by means of continuous relative
motion, an electrical conductor or system of conductors forming part of
a circuit is caused to cut the lines of a magnetic field or fields; the
cutting of the magnetic flux induces an electromotive force in the
conductors, and when the circuit is closed a current flows, whereby
mechanical energy is converted into electrical energy.

  Little practical use could be made of electrical energy so long as its
  only known sources were frictional machines and voltaic batteries. The
  cost of the materials for producing electrical currents on a large
  scale by chemical action was prohibitive, while the frictional machine
  only yielded very small currents at extremely high potentials. In the
  dynamo, on the other hand, electrical energy in a convenient form
  could be cheaply and easily obtained by mechanical means, and with its
  invention the application of electricity to a wide range of commercial
  purposes became economically possible. As a converter of energy from
  one form to another it is only surpassed in efficiency by another
  electrical appliance, namely, the transformer (see TRANSFORMERS). In
  this there is merely conversion of electrical energy at a high
  potential into electrical energy at a low potential, or vice versa,
  but in the dynamo the mechanical energy which must be applied to
  maintain the relative movement of magnetic field and conductor is
  absorbed, and reappears in an electrical form. A true transformation
  takes place, and the proportion which the rate of delivery of
  electrical energy bears to the power absorbed, or in other words the
  _efficiency_, is the more remarkable. The useful return or "output" at
  the terminals of a large machine may amount to as much as 95% of the
  mechanical energy which forms the "input." Since it needs some prime
  mover to drive it, the dynamo has not made any direct addition to our
  sources of energy, and does not therefore rank with the primary
  battery or oil-engine, or even the steam-engine, all of which draw
  their energy more immediately from nature. Yet by the aid of the
  dynamo the power to be derived from waterfalls can be economically and
  conveniently converted into an electrical form and brought to the
  neighbouring factory or distant town, to be there reconverted by
  motors into mechanical power. Over any but very short distances energy
  is most easily transmitted when it is in an electrical form, and
  turbine-driven dynamos are very largely and successfully employed for
  such transmission. Thus by conducing to the utilization of water-power
  which may previously have had but little value owing to its
  disadvantageous situation, the dynamo may almost be said to have added
  another to our available natural resources.

The two essential parts of the dynamo, as required by its definition,
may be illustrated by the original disk machine of Faraday. They are (1)
the _iron magnet_, between the poles of which a magnetic field exists,
and (2) the _electrical conductors_, represented by the rotating copper
disk. The sector of the disk cutting the lines of the field forms part
of a closed electric circuit, and has an E.M.F. induced in it, by reason
of which it is no longer simply a conductor, but has become "active." In
its more highly developed form the simple copper disk is elaborated into
a system of many active wires or bars which form the "winding," and
which are so interconnected as to add up their several E.M.F.'s. Since
these active wires are usually mounted on an iron structure, which may
be likened to the keeper or "armature" of a magnet rotating between its
poles, the term "armature" has been extended to cover not only the iron
core, but also the wires on it, and when there is no iron core it is
even applied to the copper conductors themselves. In the dynamo of
Faraday the "armature" was the rotating portion, and such is the case
with modern continuous-current dynamos; in alternators, however, the
magnet, or a portion of it, is more commonly rotated while the armature
is stationary. It is in fact immaterial to the action whether the one or
the other is moved, or both, so long as their relative motion causes the
armature conductors to cut the magnetic flux. As to the ultimate reason
why an E.M.F. should be thereby induced, physical science cannot as yet
yield any surer knowledge than in the days of Faraday.[3] For the
engineer, it suffices to know that the E.M.F. of the dynamo is due to
the cutting of the magnetic flux by the active wires, and, further, is
proportional to the rate at which the lines are cut.[4]

[Illustration: FIG. 2.]

The equation of the _electromotive force_ which is required in order to
render this statement quantitative must contain three factors, namely,
the density of the flux in the air-gap through which the armature
conductors move, the active length of these wires, and the speed of
their movement. For given values of the first and third factors and a
single straight wire moved parallel to itself through a uniform field,
the maximum rate of cutting is evidently obtained when the three
directions of the lines of the conductor's length and of the relative
motion are respectively at right angles to each other, as shown by the
three co-ordinate axes of fig. 2. The E.M.F. of the single wire is then

  E = B_gLV × 10^(-8) volts  (1)

where B_g is the density of the flux within the air-gap expressed in
C.G.S. lines per square centimetre, L is the active length of the
conductor within the field in centimetres, and V is the velocity of
movement in centimetres per second. Further, the direction in which the
E.M.F. has the above maximum value is along the length of the conductor,
its "sense" being determined by the direction of the movement[5] in
relation to the direction of the field.

The second fundamental equation of the dynamo brings to light its
mechanical side, and rests on H.C. Oersted's discovery of the
interaction of a magnetic field and an electric current. If a straight
electric conductor through which a current is passing be so placed in a
magnetic field that its length is not parallel to the direction of the
lines of flux, it is acted on by a force which will move it, if free, in
a definite direction relatively to the magnet; or if the conductor is
fixed and the magnet is free, the latter will itself move in the
opposite direction. Now in the dynamo the active wires are placed so
that their length is at right angles to the field; hence when they are
rotated and an electric current begins to flow under the E.M.F. which
they induce, a mutual force at once arises between the copper conductors
and the magnet, and the direction of this force must by Lenz's law be
opposed to the direction of the movement. Thus as soon as the disk of
fig. 1 is rotated and its circuit is closed, it experiences a mechanical
pull or drag which must be overcome by the force applied to turn the
disk. While the magnet must be firmly held so as to remain stationary,
the armature must be of such mechanical construction that its wires can
be forcibly driven through the magnetic field against the mutual pull.
This law of electrodynamic action may be quantitatively stated in an
_equation of mechanical force_, analogous to the equation (I.) of
electromotive force, which states the law of electromagnetic induction.
If a conductor of length L cm., carrying a current C amperes, is
immersed in a field of uniform density B_g, and the length of the
conductor is at right angles to the direction of the lines, it is acted
on by a force

  F = B_gLC × 10^(-1) dynes,  (2)

and the direction of this force is at right angles to the conductor and
to the field. The rate at which electrical energy is developed, when
this force is overcome by moving the conductor as a dynamo through the
field, is EC = B_gLVC × 10^(-8) watts, whence the equality of the
mechanical power absorbed and the electrical power developed (as
required by the law of the conservation of energy) is easily
established. The whole of this power is not, however, available at the
terminals of the machine; if R_a be the resistance of the armature in
ohms, the passage of the current C_a through the armature conductors
causes a drop of pressure of C_aR_a volts, and a corresponding loss of
energy in the armature at the rate of C_a²R_a watts. As the resistance
of the external circuit R_e is lowered, the current C = E_a/(R_e + R_a)
is increased. The increase of the current is, however, accompanied by a
progressive increase in the loss of energy over the armature, and as
this is expended in heating the armature conductors, their temperature
may rise so much as to destroy the insulating materials with which they
are covered. Hence the temperature which the machine may be permitted to
attain in its working is of great importance in determining its output,
the current which forms one factor therein being primarily limited by
the heating which it produces in the armature winding. The lower the
resistance of the armature, the less the rise of its temperature for a
given current flowing through it; and the reason for the almost
universal adoption of copper as the material for the armature conductors
is now seen to lie in its high conductivity.[6]

Since the voltage of the dynamo is the second factor to which its output
is proportional, the conditions which render the induced E.M.F. a
maximum must evidently be reproduced as far as possible in practice, if
the best use is to be made of a given mass of iron and copper. The first
problem, therefore, in the construction of the dynamo is the disposition
of the wires and field in such a manner that the three directions of
field, length of active conductors, and movement are at right angles to
one another, and so that the relative motion is continuous.
Reciprocating motion, such as would be obtained by direct attachment of
the conductors to the piston of a steam-engine, has been successfully
employed only in the special case of an "oscillator,"[7] producing a
small current very rapidly changing in direction. Rotary motion is
therefore universally adopted, and with this two distinct cases arise.
Either (A) the active length of the wire is parallel to the axis of
rotation, or (B) it is at right angles to it.

[Illustration: FIG. 3.]

(A) If a conductor is rotated in the gap between the poles of a
horse-shoe magnet, and these poles have plane parallel faces opposing
one another as in fig. 3, not only is the density of the flux in the
interpolar gap small, but the direction of movement is not always at
right angles to the direction of the lines, which for the most part pass
straight across from one opposing face to the other. When the conductor
is midway between the poles (i.e. either at its highest or lowest
point), it is at this instant sliding along the lines and does not cut
them, so that its E.M.F. is zero. Taking this position as the
starting-point, as the conductor moves round, its rate of line-cutting
increases to a maximum when it has moved through a right angle and is
opposite to the centre of a pole-face (as in fig. 3), from which point
onward the rate decreases to zero when it has moved through 180°. Each
time the conductor crosses a line drawn symmetrically through the gap
between the poles and at right angles to the axis of rotation, the
E.M.F. along its length is reversed in direction, since the motion
relatively to the direction of the field is reversed. If the ends of the
active conductor are electrically connected to two collecting rings
fixed upon, but insulated from, the shaft, two stationary brushes bb can
be pressed on the rings so as to make a sliding contact. An external
circuit can then be connected to the brushes, which will form the
"terminals" of the machine, the periodically reversed or alternating
E.M.F. induced in the active conductor will cause an alternating current
to flow through conductor and external circuit, and the simplest form of
"alternator" is obtained. If the field cut by the straight conductor is
of uniform density, and all the lines pass straight across from one
pole-face to the other (both of which assumptions are approximately
correct), a curve connecting the instantaneous values of the E.M.F. as
ordinates with time or degrees of angular movement as abscissae (as
shown at the foot of fig. 3), will, if the speed of rotation be uniform,
be a sine curve. If, however, the conductor is mounted on an iron
cylinder (fig. 4),[8] a sufficient margin being allowed for mechanical
clearance between it and the poles, not only will the reluctance of the
magnetic circuit be reduced and the total flux and its density in the
air-gap B_g be thereby increased, but the path of the lines will become
nearly radial, except at the "fringe" near the edges of the pole-tips;
hence the relative directions of the movement and of the lines will be
continuously at right angles. The shape of the E.M.F. curve will then be
as shown in fig. 4--flat-topped, with rounded corners rapidly sloping
down to the zero line.

[Illustration: FIG. 4.]

But a single wire cannot thus be made to give more than a few volts, and
while dynamos for voltages from 5 to 10 are required for certain
purposes, the voltages in common use range from 100 to 10,000. It is
therefore necessary to connect a number of such wires in series, so as
to form an "armature winding." If several similar conductors are
arranged along the length of the iron core parallel to the first (fig.
5), the E.M.F.'s generated in the conductors which at any moment are
under the same pole are similarly directed, and are opposite to the
directions of the E.M.F.'s in the conductors under the other pole (cf
fig. 5 where the dotted and crossed ends of the wires indicate E.M.F.'s
directed respectively towards and away from the observer). Two distinct
methods of winding thence arise, the similarity of the E.M.F.'s under
the same pole being taken advantage of in the first, and the opposite
E.M.F.'s under N and S poles in the second.

[Illustration: FIG. 5.]

[Illustration: FIG. 6.]

1. The first, or _ring_-winding, was invented by Dr Antonio Pacinotti of
Florence[9] in 1860, and was subsequently and independently reintroduced
in 1870[10] by the Belgian electrician, Zénobe Théophile Gramme, whence
it is also frequently called the "Gramme" winding. By this method the
farther end of conductor 1 (fig. 5) is joined in series to the near end
of conductor 2; this latter lies next to it on the surface of the core
or immediately above it, so that both are simultaneously under the same
pole-piece. For this series connexion to be possible, the armature core
must be a hollow cylinder, supported from the shaft on an open
non-magnetic spider or hub, between the arms of which there is room for
the internal wire completing the loop (fig. 6). The end of one complete
loop or turn embracing one side of the armature core thus forms the
starting-point for another loop, and the process can be continued if
required to form a coil of two or more turns. In the ring armature the
iron core serves the double purpose of conducting the lines across from
one pole to the other, and also of shielding from the magnetic flux the
hollow interior through which the connecting wires pass. Any lines which
leak across the central space are cut by the internal wires, and the
direction of cutting is such that the E.M.F. caused thereby opposes the
E.M.F. due to the active conductors proper on the external surface. If,
however, the section of iron in the core be correctly proportioned, the
number of lines which cross the interior will bear but a small ratio to
those which pass entirely through the iron, and the counter E.M.F. of
the internal wires will become very small; they may then be regarded
simply as connectors for joining the external active wires in series.

[Illustration: FIG. 7.]

2. The second or _drum_ method was used in the original "shuttle-wound"
armatures invented by Dr Werner von Siemens in 1856, and is sometimes
called the "Siemens" winding. The farther end of conductor 1 (fig. 5) is
joined by a connecting wire to the farther end of another conductor 2'
situated nearly diametrically opposite on the other side of the core and
under the opposite pole-piece. The near end of the complete loop or turn
is then brought across the end of the core, and can be used as the
starting-point for another loop beginning with conductor 2, which is
situated by the side of the first conductor. The iron core may now be
solid from the surface to the shaft, since no connecting wires are
brought through the centre, and each loop embraces the entire armature
core (fig. 7). By the formation of two loops in the ring armature and of
the single loop in the drum armature, two active wires are placed in
series; the curves of instantaneous E.M.F. are therefore similar in
shape to that of the single wire (fig. 4), but with their ordinates
raised throughout to double their former height, as shown at the foot of
fig. 6.

Next, if the free ends of either the ring or drum loops, instead of
being connected to two collecting rings, are attached to the two halves
of a split-ring insulated from the shaft (as shown in fig. 7 in
connexion with a drum armature), and the stationary brushes are so set
relatively to the loops that they pass over from the one half of the
split-ring to the other half at the moment when the loops are passing
the centre of the interpolar gap, and so are giving little or no E.M.F.,
each brush will always remain either positive or negative. The current
in the external circuit attached to the brushes will then have a
constant direction, although the E.M.F. in the active wires still
remains alternating; the curve of E.M.F. obtained at the brushes is thus
(as in fig. 7) entirely above the zero line. The first dynamo of H.
Pixii,[11] which immediately followed Faraday's discovery, gave an
alternating current, but in 1832[12] the alternator was converted into a
machine giving a _unidirected current_ by the substitution of a
rudimentary "commutator" in place of mercury collecting cups.

(B) So far the length of the active wires has been parallel to the axis
of rotation, but they may equally well be arranged perpendicularly
thereto. The poles will then have plane faces and the active wires will
be disposed with their length approximately radial to the axis of the
shaft. In order to add their E.M.F.'s in series, two types of winding
may be employed, which are precisely analogous in principle to the ring
and drum windings under arrangement (A).

3. The _discoidal_ or flat-ring armature is equivalent to a ring of
which the radial depth greatly exceeds the length, with the poles
presented to one side of the ring instead of embracing its cylindrical
surface. A similar set of poles is also presented to the opposite side
of the ring, like poles being opposite to one another, so that in effect
each polar surface is divided into two halves, and the groups of lines
from each side bifurcate and pass circumferentially through the armature
core to issue into the adjacent poles of opposite sign.

4. In the _disk_ machine, no iron core is necessary for the armature,
the two opposite poles of unlike sign being brought close together,
leaving but a short path for the lines in the air-gap through which the
active wires are rotated.

If the above elementary dynamos are compared with fig. 1, it will be
found that they all possess a distinctive feature which is not present
in the original disk machine of Faraday. In the four types of machine
above described each active wire in each revolution first cuts the group
of lines forming a field in one direction, and then cuts the same lines
again in the opposite direction relatively to the sense of the lines, so
that along the length of the wire the E.M.F. alternates in direction.
But in the dynamo of fig. 1 the sector of the copper disk which is at
any moment moving through the magnetic field and which forms the single
active element is always cutting the lines in the same manner, so that
the E.M.F. generated along its radial length is continuous and unchanged
in direction. This radical distinction differentiates the two classes of
_heteropolar_ and _homopolar_ dynamos, Faraday's disk machine of fig. 1
being the type of the latter class. In it the active element may be
arranged either parallel or at right angles to the axis of rotation;
but in both cases, in order to increase the E.M.F. by placing two or
more elements in series, it becomes necessary either (1) to employ some
form of sliding contact by which the current may be collected from the
end of one active element and passed round a connecting wire into the
next element without again cutting the field in the reverse direction,
or (2) to form on the armature a loop of which each side is alternately
active and inactive. The first method limits the possibilities of the
homopolar machine so greatly when large currents and high voltages are
required that it is now only used in rare instances, as e.g.
occasionally in dynamos driven by steam-turbines which have a very high
speed of rotation. The second alternative may be carried into effect
with any of the four methods of armature winding, but is practically
confined to the drum and disk types. In its drum form the field is
divided into two or more projecting poles, all of the same sign, with
intervening neutral spaces of equal width, and the span of the loop in
the direction of rotation is at least equal to the width of a polar
projection, as in fig. 8, where two polar projections are shown. Each
side of the loop then plays a dual part; it first cuts the lines of one
polar projection and generates an E.M.F., and next becomes an inactive
connecting wire, while the action is taken up by the opposite side of
the loop which has previously served as a connector but now cuts the
lines of the next polar projection. The E.M.F. is thus always in the
same direction along the side which is at any moment active, but
alternates round the loop as a whole, and the distinctive peculiarity of
the homopolar machine, so soon as any form of "winding" is introduced
into its armature, is lost. It results that the homopolar principle,
which would prima facie appear specially suitable for the generation of
a unidirectional E.M.F. and continuous current, can seldom be used for
this purpose and is practically confined to alternators. It may
therefore be said that in almost all dynamos, whether they supply an
alternating or a continuous current in the external circuit, the E.M.F.
and current in the armature are alternating.

[Illustration: FIG. 8.]

Ring winding was largely employed in early continuous-current dynamos
and also in the alternators of Gramme and H. Wilde, and later of Auguste
de Méritens. Disk winding was also successfully introduced for
alternators, as in the magneto-machines of Nollet (1849) and the
alternators of Wilde (1866) and Siemens (1878), and its use was
continued in the machines of W.M. Mordey and S.Z. Ferranti. But although
the ring, discoidal-ring and disk methods of winding deserve mention
from their historical importance, experience has shown that drum winding
possesses a marked superiority for both electrical and manufacturing
reasons; the three former methods have in fact been practically
discarded in its favour, so that the drum method will hereafter alone be
considered.

The drum coil, composed of several loops wound side by side, may
therefore be regarded as the constituent active element out of which the
armature winding of the modern dynamo is developed. Its application to
the multipolar machine is easily followed from fig. 9, which illustrates
the heteropolar type of dynamo. The span of the loops, which is nearly
180° or across the diameter of the two-pole machine, is reduced
approximately to 90° in the four-pole or to 60° in the six-pole machine
and so on, the curvature of the coil becoming gradually less as the
number of poles is increased. The passage of a coil through two magnetic
fields of opposite direction yields a complete wave of E.M.F., such as
is shown in fig. 6, and the time in seconds taken to pass through such a
complete cycle is the "period" of the alternating E.M.F. The number of
complete periods through which the E.M.F. of the coil passes per second
is called the "periodicity" or "frequency" of the machine. In the
bipolar machine this is equal to the number of revolutions per second,
and in the multipolar machine it is equal to the number of pairs of
fields through which the coil passes in one second; hence in general the
periodicity is pN/60, where N = the number of revolutions per minute and
p = the number of pairs of poles, and this holds true of the E.M.F. and
current round the coil, even though the E.M.F. and current furnished to
the external circuit may be rendered unidirectional or continuous. The
only difference on this point is that in the continuous-current machine
the poles are usually fewer than in the alternator, and the periodicity
is correspondingly lower. Thus in the former case the number of poles
ranges from 2 to 12 and the usual frequencies from 5 to 20; but with
alternators the frequencies in commercial use range from 25 to 120, and
in large machines driven by slow-speed engines the number of poles may
even be as high as 96.

[Illustration: FIG. 9.

I. Smooth. II. Toothed.]

[Illustration: FIG. 10.]

The drum coil may be applied either to the external surface of a
rotating armature, the field-magnet being external and stationary (fig.
9), or to the internal surface of a stationary armature (fig. 10), the
field-magnet being internal and rotating. While the former combination
is universally adopted in the continuous-current dynamo, the latter is
more usual in the modern alternator. In either case the iron armature
core must be "laminated"; the passage of the lines of the field across
its surface sets up E.M.F.'s which are in opposite directions under
poles of opposite sign, so that if the core were a solid mass a
current-sheet would flow along its surface opposite to a pole, and
complete its circuit by passing through the deeper layers of metal or by
returning in a sheet under a pole of opposite sign. Such "eddy-currents"
can be practically avoided by dividing the metal core into laminations
at right angles to the length of the active wires which are themselves
arranged to secure the greatest rate of line-cutting and maximum E.M.F.
The production of the eddy-current E.M.F. is not thereby prevented, but
the paths of the eddy-currents are so broken up that the comparatively
high resistance with which they meet reduces their amount very greatly.
The laminae must be lightly insulated from one another, right up to
their edges, so that the E.M.F.'s which still act across their thickness
will not be added up along the length of the core, but will only produce
extremely small currents circulating through the interior of the
separate laminations. Each thin iron plate is either coated with an
insulating varnish or has one of its sides covered with a sheet of very
thin paper; the thickness of the laminae is usually about one-fortieth
of an inch, and if this is not exceeded the rate at which energy is
dissipated by eddy-currents in the core is so far reduced that it does
not seriously impair the efficiency of the machine.

Lastly, the drum coils may be either attached to the surface of a smooth
armature core (fig. 9, I.), or may be wound through holes formed close
to the periphery of the core, or may be embedded in the slots between
projecting iron teeth (figs. 9 [II.] and 10). Originally employed by
Antonio Pacinotti in connexion with ring winding, the toothed armature
was after some considerable use largely discarded in favour of the
smooth core; it has, however, been reintroduced with a fuller
understanding of the special precautions necessitated in its design, and
it is now so commonly used that it may be said to have superseded the
smooth-surface armature.

  Not only does the toothed armature reduce the length of the air-gap to
  the minimum permitted by mechanical and magnetic considerations, and
  furnish better mechanical protection to the armature coils, but it
  also ensures the positive holding of the active wires against the
  mechanical drag which they experience as they pass through the
  magnetic field. Further, the active wires in the toothed armature are
  relieved of a large proportion of this mechanical drag, which is
  transferred to the iron teeth. The lines of the field, after passing
  through the air-gap proper, divide between the teeth and the slots in
  proportion to their relative permeances. Hence at any moment the
  active wires are situated in a weak field, and for a given armature
  current the force on them is only proportional to this weak field.
  This important result is connected with the fact that when the
  armature is giving current the distribution of the lines over the face
  of each tooth is distorted, so that they become denser on the
  "trailing" side than on the "leading" side;[13] the effect of the
  non-uniform distribution acting on all the teeth is to produce a
  magnetic drag on the armature core proportional to the current passing
  through the wires, so that the total resisting force remains the same
  as if the armature had a smooth core. The amount by which the stress
  on the active wires is reduced entirely depends upon the degree to
  which the teeth are saturated, but, since the relative permeability of
  iron even at a flux density of 20,000 lines per sq. cm. is to that of
  air approximately as 33:1, the embedded wires are very largely
  relieved of the driving stress. An additional gain is that solid bars
  of much greater width can be used in the toothed armature than on a
  smooth core without appreciable loss from eddy-currents within their
  mass.

  A disadvantage of the slotted core is, however, that it usually
  necessitates the lamination of the pole-pieces. If the top of the slot
  is open, and its width of opening is considerably greater than the
  length of the air-gap from the iron of the pole-face to the surface of
  the teeth, the lines become unequally distributed not only at the
  surface of the teeth, but also at the face of the pole-pieces; and
  this massing of the lines into bands causes the density at the
  pole-face to be rhythmically varied as the teeth pass under it. No
  such variation can take place in a solid mass of metal without the
  production of eddy-currents within it; hence if the width of the
  slot-opening is equal to or exceeds twice the length of the single
  air-gap, lamination of the pole-pieces in the same plane as that of
  the armature core becomes advisable.

  If the wires are threaded through holes or tunnels pierced close to
  the periphery of the core, the same advantages are gained as with open
  slots, and lamination of the pole-pieces is rendered unnecessary. But
  on the other hand, the process of winding becomes laborious and
  expensive, while the increase in the inductance of the coils owing to
  their being surrounded by a closed iron circuit is prejudicial to
  sparkless commutation in the continuous-current dynamo and to the
  regulation of the voltage of the alternator. A compromise is found in
  the half-closed slot, which is not uncommon in alternators, although
  the open slot is more usual in continuous-current dynamos.

With the addition of more turns to the elementary drum loop or of
several complete coils, new questions arise, and in connexion therewith
the two great classes of machines, viz. alternators and
continuous-current dynamos, which have above been treated side by side,
diverge considerably, so that they are best considered separately. The
electromotive-force equation of the alternator will be first deduced,
and subsequently that of the continuous-current machine.

[Illustration: FIG. 11.]

Corresponding to the number of pairs of poles in the multipolar
alternator, it is evident that there may also be an equal number of
coils as shown diagrammatically in fig. 11. The additional coils, being
similarly situated in respect to other pairs of poles, will exactly
reproduce the E.M.F. of the original coil in phase and magnitude, so
that when they are connected in series the total E.M.F. will be
proportional to the number of coils in series; or if they are connected
in parallel, while not adding to the E.M.F., they will proportionately
increase the current-carrying capacity of the combination. But within
each coil the addition of more loops will not cause an equal increase in
the total E.M.F., unless the phases of the component E.M.F.'s due to the
several turns are identical, and on this account it becomes necessary to
consider the effect of the width of the coil-side.

[Illustration: FIG. 12.]

If the additional loops are wound within the same slots as the original
loop, the winding is "concentrated," and each turn will then add the
same E.M.F. But if the coil-side is divided between two or more slots,
the phase of the E.M.F. yielded by the wires in one slot being different
from that of the wires in another neighbouring slot, the sum of all the
E.M.F.'s will be less than the E.M.F. of one component loop multiplied
by the number of loops or turns in the coil. The percentage reduction in
the E.M.F. will depend upon the number of the slots in a coil-side and
their distance apart, i.e. on the virtual width of the coil-side
expressed as a fraction of the "pole-pitch" or the distance measured
along the pitch-line from the centre of one pole to the centre of a
neighbouring pole of opposite sign (fig. 12). The winding is now to be
regarded as "grouped," since a small number of distinct phases
corresponding to the groups within the two, three or four slots have to
be compounded together. As the number of slots per coil-side is
increased, an approach is gradually made to the case of "uniform
distribution," such as would obtain in a smooth-core armature in which
the turns of the coil are wound closely side by side. Thus in the
six-turn coil of fig. 12 A, which represents the development of a
two-pole armature when the core is cut down to the shaft and opened out
flat, there are in effect six phases compounded together, each of which
differs but little from that of its next neighbour. With numerous wires
lying still closer together a large number of phases are compounded
until the distribution becomes practically uniform; the decrease in the
E.M.F., as compared with that of a single turn multiplied by the number
in series, is then immediately dependent upon the width of the coil-side
relatively to the pole-pitch.

[Illustration: FIG. 13.]

If the width of the inner loop of fig. 12 A is less than that of the
pole-face, its two sides will for some portion of each period be moving
under the same pole, and "differential action" results, the net E.M.F.
being only that due to the difference between the E.M.F.'s of the two
sides. The loop of smallest width must therefore exceed the width of
pole-face, if direct differential action is to be avoided. The same
consideration also determines the width of the outer loop; if this be
deducted from twice the pole-pitch, the difference should not be less
than the width of the pole-face, so that, e.g., in a bipolar machine the
outer loop may stand to the S. pole exactly as the inner loop stands to
the N. pole (fig. 13). In other words, the width of the coil-side must
not exceed the width of the interpolar gap between two fields. Evidently
then if the ratio of the pole-width to the pole-pitch approaches unity,
the width of the coil-side must be very small, and vice versa. A
compromise between these conflicting considerations is found if the pole
is made not much more than half the pole-pitch, and the width of the
coil-side is similarly about half the pole-pitch and therefore equal in
width to the pole (fig. 13). A single large coil, such as that of fig.
12 A, can, however, equally well be divided into two halves by taking
the end-connexions of one half of the turns round the opposite side of
the shaft (fig. 12 B), as indeed has already been done in fig. 13. Each
sheaf or band of active wires corresponding to a pole is thereby
unaffected, but the advantages are gained that the axial length of the
end-connexions is halved, and that they have less inductance. Thus if in
fig. 11 there are four turns per coil, fig. 14 is electrically
equivalent to it (save that the coils are here shown divided into two
parallel paths, each carrying half the total current). When the large
coils are divided as above described, it results that there are as many
coils as there are poles, the outer loop of the small coil having a
width equal to the pole-pitch, and the inner a width equal to the
pole-face.

[Illustration: FIG. 14.]

Such is the form which the "single-phase alternator" takes, but since
only one-half of the armature core is now covered with winding, an
entirely distinct but similar set of coils may be wound to form a second
armature circuit between the coils of the first circuit. The phase of
this second circuit will differ by 90° or a quarter of a period from
that of the first, and it may either be used to feed an entirely
separate external circuit possibly at a different pressure or, if it be
composed of the same number of turns and therefore gives the same
voltage, it may be interconnected with the first circuit to form a
"quarter-phase alternator," as will be more fully described later. By an
extension of the same process, if the width of each side of a coil is
reduced to one-sixth of the pole-pitch, three armature circuits can be
wound on the same core, and a "three-phase alternator," giving waves of
E.M.F. differing in phase by 120°, is obtained.

  The fundamental "electromotive-force equation" of the heteropolar
  alternator can now be given a more definite form. Let Z_a be the
  number of C. G. S. lines or the total flux, which issuing from any
  one pole flows through the armature core, to leave it by another pole
  of opposite sign. Since each active wire cuts these lines, first as
  they enter the armature core and then as they emerge from it to enter
  another pole, the total number of lines cut in one revolution by any
  one active wire is 2pZ_a. The time in seconds taken by one revolution
  is 60/N. The average E.M.F. induced in each active wire in one
  revolution being proportional to the number of lines cut divided by
  the time taken to cut them is therefore 2Z_a(pN/60) × 10^(-8) volts.
  The active wires which are in series and form one distinct phase may
  be divided into as many bands as there are poles; let each such band
  contain t active wires, which as before explained may either form one
  side of a single large coil or the adjacent sides of two coils when
  the large coil is divided into two halves. Since the wires are joined
  up into loops, two bands are best considered together, which with
  either arrangement yield in effect a single coil of t turns. The
  average E.M.F.'s of all the wires in the two bands when added together
  will therefore be 4Z_a(pN/60)t × 10^(-8). But unless each band is
  concentrated within a single slot, there must be some differential
  action as they cross the neutral line between the poles, so that the
  last expression is virtually the _gross_ average E.M.F. of the loops
  on the assumption that the component E.M.F.'s always act in agreement
  round the coil and do not at times partially neutralize one another.
  The _net_ average E.M.F. of the coil as a whole, or the arithmetical
  mean of all the instantaneous values of a half-wave of the actual
  E.M.F. curve, is therefore reduced to an extent depending upon the
  amount of differential action and so upon the width of the coil-side
  when this is not concentrated. Let k' = the coefficient by which the
  gross average E.M.F. must be multiplied to give the net average
  E.M.F.; then k' may be called the "width-factor," and will have some
  value less than unity when the wires of each band are spread over a
  number of slots. The net average E.M.F. of the two bands corresponding
  to a pair of poles is thus e_(av) = 4k'Z_a(pN/60)t × 10^(-8).

  The shape of the curve of instantaneous E.M.F. of the coil must
  further be taken into account. The "effective" value of an alternating
  E.M.F. is equal to the square root of the mean square of its
  instantaneous values, since this is the value of the equivalent
  unidirectional and unvarying E.M.F., which when applied to a given
  resistance develops energy at the same rate as the alternating E.M.F.,
  when the effect of the latter is averaged over one or any whole number
  of periods. Let k" = the ratio of the square root of the mean square
  to the average E.M.F. of the coil, i.e. = effective E.M.F./average
  E.M.F. Since it depends upon the shape of the E.M.F. curve, k" is also
  known as the "form-factor"; thus if the length of gap between
  pole-face and armature core and the spacing of the wires were so
  graduated as to give a curve of E.M.F. varying after a sine law, the
  form-factor would have the particular value of [pi]/2[root]2 = 1.11,
  and to this condition practical alternators more or less conform. The
  effective E.M.F. of the two bands corresponding to a pair of poles is
  thus e_(eff) = 4k'k"Z_a(pN/60)t × 10^(-8).

  In any one phase there are p pairs of bands, and these may be divided
  into q parallel paths, where q is one or any whole number of which p
  is a multiple. The effective E.M.F. of a complete phase is therefore
  pe{eff}/q. Lastly, if m = the number of phases into which the armature
  winding is divided, and [tau] = the total number of active wires on
  the armature counted all round its periphery, t = [tau]/2pm, and the
  effective E.M.F. per phase is E_a = 2k'k"Z_a(pN[tau]/60mq) × 10^(-8).

  The two factors k' and k" may be united into one coefficient, and the
  equation then takes its final form

    E_a = 2KZ_a(pN[tau]/60mq) × 10^(-8) volts  (1a)

  In the alternator q is most commonly 1, and there is only one circuit
  per phase; finally the value of K or the product of the width-factor
  and the form-factor usually falls between the limits of 1 and 1.25.

We have next to consider the effect of the addition of more armature
loops in the case of dynamos which give a unidirectional E.M.F. in
virtue of their split-ring collecting device, i.e. of the type shown in
fig. 7 with drum armature or its equivalent ring form. As before, if the
additional loops are wound in continuation of the first as one coil
connected to a single split-ring, this coil must be more or less
concentrated into a narrow band; since if the width becomes nearly equal
to or exceeds the width of the interpolar gap, the two edges of the
coil-side will just as in the alternator act differentially against one
another during part of each revolution. The drum winding with a single
coil thus gives an armature of the H- or "shuttle" form invented by Dr
Werner von Siemens. Although the E.M.F. of such an arrangement may have
a much higher maximum value than that of the curve of fig. 7 for a
single loop, yet it still periodically varies during each revolution and
so gives a pulsating current, which is for most practical uses
unsuitable. But such pulsation might be largely reduced if, for example,
a second coil were placed at right angles to the original coil and the
two were connected in series; the crests of the wave of E.M.F. of the
second coil will then coincide with the hollows of the first wave,
and although the maximum of the resultant curve of E.M.F. may be no
higher its fluctuations will be greatly decreased. A spacial
displacement of the new coils along the pole-pitch, somewhat as in a
polyphase machine, thus suggests itself, and the process may be carried
still further by increasing the number of equally spaced coils, provided
that they can be connected in series and yet can have their connexion
with the external circuit reversed as they pass the neutral line between
the poles.

[Illustration: FIG. 15.]

[Illustration: FIG. 16.]

Given two coils at right angles and with their split-rings displaced
through a corresponding angle of 90°, they may be connected in series by
joining one brush to the opposite brush of the second coil, the external
circuit being applied to the two remaining brushes.[14] The same
arrangement may again be repeated with another pair of coils in parallel
with the first, and we thus obtain fig. 15 with four split-rings, their
connexions to the loops being marked by corresponding numerals; the four
coils will give the same E.M.F. as the two, but they will be jointly
capable of carrying twice the current, owing to their division into two
parallel circuits. Now in place of the four split-rings may be employed
the greatly simplified four-segment structure shown in fig. 16, which
serves precisely the same purpose as the four split-rings but only
requires two instead of eight brushes. The effect of joining brush 2 in
fig. 15 across to brush 3, brush 4 to brush 5, 5 to 6, &c., has
virtually been to connect the end of coil A with the beginning of coil
B, and the end of coil B with the beginning of coil A', and so on, until
they form a continuous closed helix. Each sector of fig. 16 will
therefore replace two halves of a pair of adjacent split-rings, if the
end and beginning of a pair of adjacent coils are connected to it in a
regular order of sequence. The four sectors are insulated from one
another and from the shaft, and the whole structure is known as the
"commutator,"[15] its function being not simply to collect the current
but also to commute its direction in any coil as it passes the
interpolar gap. The principle of the "closed-coil continuous-current
armature" is thus reached, in which there are at least two parallel
circuits from brush to brush, and from which a practically steady
current can be obtained. Each coil is successively short-circuited, as a
brush bridges over the insulation between the two sectors which
terminate it; and the brushes must be so set that the period of
short-circuit takes place when the coil is generating little or no
E.M.F., i.e. when it is moving through the zone between the pole-tips.
The effect of the four coils in reducing the percentage fluctuation of
the E.M.F. is very marked, as shown at the foot of fig. 15 (where the
upper curve is the resultant obtained by adding together the separate
curves of coils A and B), and the levelling process may evidently be
carried still further by the insertion of more coils and more
corresponding sectors in the commutator, until the whole armature is
covered with winding. For example, figs. 17 and 18 show a ring and a
drum armature, each with eight coils and eight commutator sectors; their
resultant curve, on the assumption that a single active wire gives the
flat-topped curve of fig. 4, will be the upper wavy line of E.M.F.
obtained by adding together two of the resultant curves of fig. 15, with
a relative displacement of 45°. The amount of fluctuation for a given
number of commutator sectors depends upon the shape of the curve of
E.M.F. yielded by the separate small sections of the armature winding;
the greater the polar arc, the less the fluctuation. In practice, with a
polar arc equal to about 0.75 of the pitch, any number of sectors over
32 per pair of poles yields an E.M.F. which is sensibly constant
throughout one or any number of revolutions.

[Illustration: FIG. 17.]

[Illustration: FIG. 18.]

  The fundamental electro-motive-force equation of the
  continuous-current heteropolar machine is easily obtained by analogy
  from that of the alternator. The gross average E.W.F. from the two
  sides of a drum loop without reference to its direction is as before
  4Z_a(pN/60) × 10^(-8) volts. But for two reasons its net average
  E.M.F. may be less; the span of the loop may be less than the
  pole-pitch, so that even when the brushes are so set that the position
  of short-circuit falls on the line where the field changes its
  direction, the two sides of the loop for some little time act against
  each other; or, secondly, even if the span of the loop be equal to the
  pole-pitch, the brushes may be so set that the reversal of the
  direction of its induced E.M.F. does not coincide with reversal of the
  current by the passage of the coil under the brushes. The net average
  E.M.F. of the loop is therefore proportional to the algebraic sum of
  the lines which it cuts in passing from one brush to another, and this
  is equal to the net amount of the flux which is included within the
  loop when situated in the position of short-circuit under a brush. The
  amount of this flux may be expressed as k'Z_a where k' is some
  coefficient, less than unity if the span of the coil be less than the
  pole-pitch, and also varying with the position of the brushes. The net
  average E.M.F. of the loop is therefore

    4k'Z_a(pN/60) × 10^(-8).

  In practice the number of sections of the armature winding is so large
  and their distribution round the armature periphery is so uniform,
  that the sum total of the instantaneous E.M.F.'s of the several
  sections which are in series becomes at any moment equal to the net
  average E.M.F. of one loop multiplied by the number which are in
  series. If the winding is divided into q parallel circuits, the number
  of loops in series is [tau]/2q, so that the total E.M.F. is E_a =
  2(k'/q)Z_a(pN/60)[tau] × 10^(-8) volts. Thus as compared with the
  alternator not only is there no division of the winding into separate
  phases, but the form-factor k' disappears, since the effective and
  average E.M.F.'s are the same. Further whereas in the alternator q may
  = 1, in the continuous-current closed-coil armature there can never be
  less than two circuits in parallel from brush to brush, and if more,
  their number must always be a multiple of two, so that q can never be
  less than two and must always be an even number. Lastly, the factor k'
  is usually so closely equal to 1, that the simplified equation may in
  practice be adopted, viz.

    E_a = (2/q)(ZpN/60)[tau] × 10^(-8) volts  (1b)

  The fundamental equation of the electromotive force of the dynamo in
  its fully developed forms (1 a) (and 1 b) may be compared with its
  previous simple statement (1.). The three variable terms still find
  their equivalents, but are differently expressed, the density B_g
  being replaced by the total flux of one field Z_a, the length L of the
  single active wire by the total number of such wires [tau], and the
  velocity of movement V by the number of revolutions per second. Even
  when the speed is fixed, an endless number of changes may be rung by
  altering the relative values of the remaining two factors; and in
  successful practice these may be varied between fairly wide limits
  without detriment to the working or economy of the machine. While it
  may be said that the equation of the E.M.F. was implicitly known from
  Faraday's time onwards, the difficulty under which designers laboured
  in early days was the problem of choosing the correct relation of Z_a
  or [tau] for the required output; this, again, was due chiefly to the
  difficulty of predetermining the total flux before the machine was
  constructed. The general error lay in employing too weak a field and
  too many turns on the armature, and credit must here be given to the
  American inventors, E. Weston and T.A. Edison, for their early
  appreciation of the superiority in practical working of the drum
  armature, with comparatively few active wires rotating in a strong
  field.


  The armature core.

_Continuous-current Dynamos._--On passing to the separate consideration
of alternators and continuous-current dynamos, the chief constructive
features of the latter will first be taken in greater detail. As already
stated in the continuous-current dynamo the armature is usually the
rotating portion, and the necessity of laminating its core has been
generally described. The thin iron stampings employed to build up the
core take the form of circular washers or "disks," which in small
machines are strung directly on the shaft; in larger multipolar
machines, in which the required radial depth of iron is small relatively
to the diameter, a central cast iron hub supports the disks. Since the
driving force is transmitted through the shaft to the disks, they must
in the former case be securely fixed by keys sunk into the shaft; when a
central hub is employed (fig. 19) it is keyed to the shaft, and its
projecting arms engage in notches stamped on the inner circumference of
the disks, or the latter have dovetailed projections fitting into the
arms. The disks are then tightly compressed and clamped between stout
end-plates so as to form a nearly solid iron cylinder of axial length
slightly exceeding the corresponding dimension of the poles. If the
armature is more than 4 ft. in diameter, the disks become too large to
be conveniently handled in one piece, and are therefore made in
segments, which are built up so as to break joint alternately. Prior to
assemblage, the external circumference of each disk is notched in a
stamping machine with the required number of slots to receive the
armature coils, and the longitudinal grooves thereby formed in the
finished core only require to have their sharp edges smoothed off so
that there may be no risk of injury to the insulation of the coils.

[Illustration: FIG. 19.]


  Armature winding.

With open slots either the armature coils may be encased with wrappings
of oiled linen, varnished paper and thin flexible micanite sheeting in
order to insulate them electrically from the iron slots in which they
are afterwards embedded; or the slots may be themselves lined with
moulded troughs of micanite, &c., for the reception of the armature
coils, the latter method being necessary with half-closed slots.
According to the nature of the coils armatures may be divided into the
two classes of coil-wound and bar-wound. In the former class, round
copper wire, double-cotton covered, is employed, and the coils are
either wound by hand directly on to the armature core, or are shaped on
formers prior to being inserted in the armature slots. Hand-winding is
now only employed in very small bipolar machines, the process being
expensive and accompanied by the disadvantage that if one section
requires to be repaired, the whole armature usually has to be dismantled
and re-wound. Former-wound coils are, on the other hand, economical in
labour, perfectly symmetrical and interchangeable, and can be thoroughly
insulated before they are placed in the slots. The shapers employed in
the forming process are very various, but are usually arranged to give
to the finished coil a lozenge shape, the two straight active sides
which fit into the straight slots being joined by V-shaped ends; at each
apex of the coil the wire is given a twist, so that the two sides fall
into different levels, an upper and a lower, corresponding to the two
layers which the coil-sides form on the finished armature. Rectangular
wire of comparatively small section may be similarly treated, and if
only one loop is required per section, wide and thin strip can be bent
into a complete loop, so that the only soldered joints are those at the
commutator end where the loops are interconnected. But finally with
massive rectangular conductors, the transition must be made to
bar-winding, in which each bar is a half-loop, insulated by being taped
after it has been bent to the required shape; the separate bars are
arranged on the armature in two layers, and their ends are soldered
together subsequently to form loops. As a general rule, whether bars or
former-wound coils are employed, the armature is barrel-wound, i.e. the
end-connexions project outwards from the slots with but little change of
level, so that they form a cylindrical mass supported on projections
from the end-plates of the core (fig. 19); but, in certain cases, the
end-connexions are bent downwards at right angles to the shaft, and they
may then consist of separate strips of copper bent to a so-called
butterfly or evolute shape.

After the coils or loops have been assembled in the slots on the
armature core, and the commutator has been fixed in place on the shaft,
the soldering of the ends of the coils proceeds, by which at once the
union of the end of one coil with the beginning of the next, and also
their connexion to the commutator sectors, is effected, and in this lies
the essential part of armature winding.

[Illustration: FIG. 20.

Lap-loops]


    Lap-winding.

  The development of the modern drum armature, with its numerous coils
  connected in orderly sequence into a symmetrical winding, as
  contrasted with the earlier Siemens armatures, was initiated by F. von
  Hefner Alteneck (1871), and the laws governing the interconnexion of
  the coils have now been elaborated into a definite system of winding
  formulae. Whatever the number of wires or bars in each side of a coil,
  i.e. whether it consist of a single loop or of many turns, the final
  connexions of its free ends are not thereby affected, and it may be
  mentally replaced by a single loop with two active inducing sides. The
  coil-sides in their final position are thus to be regarded as separate
  primary elements, even in number, and distributed uniformly round the
  armature periphery or divided into small, equally spaced groups by
  being located within the slots of a toothed armature. Attention must
  then be directed simply to the span of the back connexion between the
  elements at the end of the armature further from the commutator, and
  to the span of the front connexion by which the last turn of a coil is
  finally connected to the first turn of the next in sequence, precisely
  as if each coil of many turns were reduced to a single loop. In order
  to avoid direct differential action, the span of the back connexion
  which fixes the width of the coil must exceed the width of the
  pole-face, and should not be far different from the pole-pitch; it is
  usually a little less than the pole-pitch. Taking any one element as
  No. 1 in fig. 20, where for simplicity a smooth-core bipolar armature
  is shown, the number of winding-spaces, each to be occupied by an
  element, which must be counted off in order to find the position of
  the next element in series, is called the "pitch" of the
  end-connexion, front or back, as the case may be. Thus the back pitch
  of the winding as marked by the dotted line in fig. 20 is 7, the
  second side of the first loop being the element numbered 1 + 7 = 8. In
  forming the front end-connexion which completes the loop and joins it
  to the next in succession, two possible cases present themselves. By
  the first, or "lap-winding," the front end-connexion is brought
  backwards, and passing on its way to a junction with a commutator
  sector is led to a third element lying within the two sides of the
  first loop, i.e. the second loop starts with the element, No. 3, lying
  next but one to the starting-point of the first loop. The winding
  therefore returns backwards on itself to form each front end, but as a
  whole it works continually forwards round the armature, until it
  finally "re-enters," after every element has been traversed. The
  development of the completed winding on a flat surface shows that it
  takes the form of a number of partially overlapping loops, whence its
  name originates. The firm-line portion of fig. 21 gives the
  development of an armature similar to that of fig. 18 when cut through
  at the point marked X and opened out; two of the overlapping loops are
  marked thereon in heavy lines. The multipolar lap-wound armature is
  obtained by simply repeating the bipolar winding p times, as indicated
  by the dotted additions of fig. 21 which convert it from a two-pole to
  a four-pole machine. The characteristic feature of the lap-wound
  armature is that there are as many parallel paths from brush to brush,
  and as many points at which the current must be collected, as there
  are poles. As the bipolar closed-coil continuous-current armature has
  been shown to consist in reality of two circuits in parallel, each
  giving the same E.M.F. and carrying half the total current, so the
  multipolar lap-wound drum consists of p pairs of parallel paths, each
  giving the same E.M.F. and carrying 1/2p of the total current. Thus in
  equation 1.b we have q = 2p, and the special form which the _E.M.F.
  equation of the lap-wound armature_ takes is E_[alpha] = Z_a
  (N/60)[tau] × 10^(-8) volts. All the brushes which are of the same
  sign must be connected together in order to collect the total armature
  current. The several brush-sets of the multipolar lap-wound machine
  may again be reduced to two by "cross-connexion" of sectors situated
  360°/p apart, but this is seldom done, since the commutator must then
  be lengthened p times in order to obtain the necessary brush
  contact-surface for the collection of the entire current.

  [Illustration: FIG. 21.]

  [Illustration: FIG. 22.

  Wave-loops]

  [Illustration: FIG. 23.]


    Wave-winding.

  But for many purposes, especially where the voltage is high and the
  current small, it is advantageous to add together the inductive effect
  of the several poles of the multipolar machine by throwing the E.M.F's
  of half the total number of elements into series, the number of
  parallel circuits being conversely again reduced to two. This is
  effected by the second method of winding the closed-coil continuous
  current drum, which is known as "wave-winding." The front pitch is now
  in the same direction round the armature as the back pitch (fig. 22),
  so that the beginning of the second loop, i.e. element No. 15, lies
  outside the first loop. After p loops have been formed and as many
  elements have been traversed as there are poles, the distance covered
  either falls short of or exceeds a complete tour of the armature by
  two winding-spaces, or the width of two elements. A second and third
  tour are then made, and so on, until finally the winding again closes
  upon itself. When the completed winding is developed as in fig. 23, it
  is seen to work continuously forwards round the armature in zigzag
  waves, one of which is marked in heavy lines, and the number of
  complete tours is equal to the average of the back and front pitches.
  Since the number of parallel circuits from brush to brush is q = 2,
  the _E.M.F. equation of the wave-wound drum_ is E_a = pZ_a (N/60)[tau]
  × 10^(-8) volts. Only two sets of brushes are necessary, but in order
  to shorten the length of the commutator, other sets may also be added
  at the point of highest and lowest potential up to as many in number
  as there are poles. Thus the advantage of the wave-wound armature is
  that for a given voltage and number of poles the number of active
  wires is only 1/p of that in the lap-wound drum, each being of larger
  cross-section in order to carry p times as much current; hence the
  ratio of the room occupied by the insulation to the copper area is
  less, and the available space is better utilized. A further advantage
  is that the two circuits from brush to brush consist of elements
  influenced by all the poles, so that if for any reason, such as
  eccentricity of the armature within the bore of the pole-pieces, or
  want of uniformity in the magnetic qualities of the poles, the flux of
  each field is not equal to that of every other, the equality of the
  voltage produced by the two halves of the winding is not affected
  thereby.

  In appearance the two classes of armatures, lap and wave, may be
  distinguished in the barrel type of winding by the slope of the upper
  layer of back end-connexions, and that of the front connexions at the
  commutator end being parallel to one another in the latter, and
  oppositely directed in the former.

[Illustration: FIG. 24.]

After completion of the winding, the end-connexions are firmly bound
down by bands of steel or phosphor bronze binding wire, so as to resist
the stress of centrifugal force. In the case of smooth-surface
armatures, such bands are also placed at intervals along the length of
the armature core, but in toothed armatures, although the coils are
often in small machines secured in the slots by similar bands of a
non-magnetic high-resistance wire, the use of hard-wood wedges driven
into notches at the sides of the slots becomes preferable, and in very
large machines indispensable. The external appearance of a typical
armature with lap-winding is shown in fig. 24.


  The commutator.

A sound mechanical construction of the commutator is of vital importance
to the good working of the continuous-current dynamo. The narrow,
wedge-shaped sectors of hard-drawn copper, with their insulating strips
of thin mica, are built up into a cylinder, tightly clamped together,
and turned in the lathe; at each end a V-shaped groove is turned, and
into these are fitted rings of micanite of corresponding section (fig.
19); the whole is then slipped over a cast iron sleeve, and at either
end strong rings are forced into the V-shaped grooves under great
pressure and fixed by a number of closely-pitched tightening bolts. In
dynamos driven by steam-turbines in which the peripheral speed of the
commutator is very high, rings of steel are frequently shrunk on the
surface of the commutator at either end and at its centre. But in every
case the copper must be entirely insulated from the supporting body of
metal by the interposition of mica or micanite and the prevention of any
movement of the sectors under frequent and long-continued heating and
cooling calls for the greatest care in both the design and the
manufacture.


  Forms of field-magnet.

On passing to the second fundamental part of the dynamo, namely, the
field-magnet, its functions may be briefly recalled as follows:--It has
to supply the magnetic flux; to provide for it an iron path as nearly
closed as possible upon the armature, save for the air-gaps which must
exist between the pole-system and the armature core, the one stationary
and the other rotating; and, lastly, it has to give the lines such
direction and intensity within the air-gaps that they may be cut by the
armature wires to the best advantage. Roughly corresponding to the three
functions above summarized are the three portions which are more or less
differentiated in the complete structure. These are: (1) the magnet
"cores" or "_limbs_," carrying the exciting coils whereby the inert iron
is converted into an electro-magnet; (2) the _yoke_, which joins the
limbs together and conducts the flux between them; and (3) the
_pole-pieces_, which face the armature and transmit the lines from the
limbs through the air-gap to the armature core, or vice versa.

  [Illustration: FIG. 25.]

  Of the countless shapes which the field-magnet may take, it may be
  said, without much exaggeration, that almost all have been tried; yet
  those which have proved economical and successful, and hence have met
  with general adoption, may be classed under a comparatively small
  number of types. For bipolar machines the _single horse-shoe_ (fig.
  25), which is the lineal successor of the permanent magnet employed in
  the first magneto-electric machines, was formerly very largely used.
  It takes two principal forms, according as the pole-pieces and
  armature are above or beneath the magnet limbs and yoke. The
  "over-type" form is best suited to small belt-driven dynamos, while
  the "under-type" is admirably adapted to be directly driven by the
  steam-engine, the armature shaft being immediately coupled to the
  crank-shaft of the engine. In the latter case the magnet must be
  mounted on non-magnetic supports of gun-metal or zinc, so as to hold
  it at some distance away from the iron bedplate which carries both
  engine and dynamo; otherwise a large proportion of the flux which
  passes through the magnet limbs would leak through the bedplate across
  from pole to pole without passing through the armature core, and so
  would not be cut by the armature wires.

  [Illustration: FIG. 26.]

  Next may be placed the "Manchester" field (fig. 26)--the type of a
  divided magnetic circuit in which the flux forming one field or pole
  is divided between two magnets. An exciting coil is placed on each
  half of the double horse-shoe magnet, the pair being so wound that
  consequent poles are formed above and below the armature. Each magnet
  thus carries one-half of the total flux, the lines of the two halves
  uniting to form a common field where they issue forth into or leave
  the air-gaps. The pole-pieces may be lighter than in the single
  horse-shoe type, and the field is much more symmetrical, whence it is
  well suited to ring armatures of large diameter. Yet these advantages
  are greatly discounted by the excessive magnetic leakage, and by the
  increased weight of copper in the exciting coils. Even if the greater
  percentage which the leakage lines bear to the useful flux is
  neglected, and the cross sectional area of each magnet core is but
  half that of the equivalent single horse-shoe, the weight of wire in
  the double magnet for the same rise of temperature in the coils must
  be some 40% more than in the single horse-shoe, and the rate at which
  energy is expended in heating the coils will exceed that of the single
  horse-shoe in the same proportion.

  Thirdly comes the two-pole _ironclad_ type, so called from the
  exciting coil being more or less encased by the iron yoke; this latter
  is divided into two halves, which pass on either side of the armature.
  Unless the yoke be kept well away from the polar edges and armature,
  the leakage across the air into the yoke becomes considerable,
  especially if only one exciting coil is used, as in fig. 27 A; it is
  better, therefore, to divide the excitation between two coils, as in
  fig. 27 B, when the field also becomes symmetrical.

  From this form is easily derived the _multipolar_ type of fig. 28 or
  fig. 29, which is by far the most usual for any number of poles from
  four upwards; its leakage coefficient is but small, and it is
  economical in weight both of iron and copper.


    Materials of magnets.

  As regards the materials of which magnets are made, generally speaking
  there is little difference in the permeability of "wrought iron" or
  "mild steel forgings" and good "cast steel"; typical (B, H) curves
  connecting the magnetizing force required with different
  flux-densities for these materials are given under ELECTROMAGNETISM.
  On the other hand there is a marked inferiority in the case of "cast
  iron," which for a flux-density of B = 8000 C.G.S. lines per sq. cm.
  requires practically the same number of ampere-turns per centimetre
  length as steel requires for B = 16,000. Whatever the material, if the
  flux-density be pressed to a high value the ampere-turns are very
  largely increased owing to its approaching saturation, and this
  implies either a large amount of copper in the field coils or an undue
  expenditure of electrical energy in their excitation. Hence there is a
  limit imposed by practical considerations to the density at which the
  magnet should be worked, and this limit may be placed at about B =
  16,000 for wrought iron or steel, and at half this value for cast
  iron. For a given flux, therefore, the cast iron magnet must have
  twice the sectional area and be twice as heavy, although this
  disadvantage is partly compensated by its greater cheapness. If,
  however, cast iron be used for the portion of the magnetic circuit
  which is covered with the exciting coils, the further disadvantage
  must be added that the weight of copper on the field-magnet is much
  increased, so that it is usual to employ forgings or cast steel for
  the magnet cores on which the coils are wound. If weight is not a
  disadvantage, a cast iron yoke may be combined with the wrought iron
  or cast steel magnet cores. An absence of joints in the magnetic
  circuit is only desirable from the point of view of economy of expense
  in machining the component parts during manufacture; when the surfaces
  which abut against each other are drawn firmly together by screws, the
  want of homogeneity at the joint, which virtually amounts to the
  presence of a very thin film of air, produces little or no effect on
  the total reluctance by comparison with the very much longer air-gaps
  surrounding the armature. In order to reduce the eddy-currents in the
  pole-pieces, due to the use of toothed armatures with relatively wide
  slots, the poles themselves must be laminated, or must have fixed to
  them laminated pole-shoes, built up of thin strips of mild steel
  riveted together (as shown in fig. 29).

  [Illustration: FIG. 27.]

  [Illustration: FIG. 28.]

  However it be built up, the mechanical strength of the magnet system
  must be carefully considered. Any two surfaces between which there
  exists a field of density B_g experience a force tending to draw them
  together proportional to the square of the density, and having a value
  of B_g²/(1.735 × 10^6) lb. per sq. in. of surface, over which the
  density may be regarded as having the uniform value B_g. Hence, quite
  apart from the torque with which the stationary part of the dynamo
  tends to turn with the rotating part as soon as current is taken out
  of the armature, there exists a force tending to make the pole-pieces
  close on the armature as soon as the field is excited. Since both
  armature and magnet must be capable of resisting this force, they
  require to be rigidly held; although the one or the other must be
  capable of rotation, there should otherwise be no possibility of one
  part of the magnetic circuit shifting relatively to any other part. An
  important conclusion may be drawn from this circumstance. If the
  armature be placed exactly concentric within the bore of the poles,
  and the two or more magnetic fields be symmetrical about a line
  joining their centres, there is no tendency for the armature core to
  be drawn in one direction more than in another; but if there is any
  difference between the densities of the several fields, it will cause
  an unbalanced stress on the armature and its shaft, under which it
  will bend, and as this bending is continually reversed relatively to
  the fibres of the shaft, they will eventually become weakened and give
  way. Especially is this likely to take place in dynamos with short
  air-gaps, wherein any difference in the lengths of the air-gaps
  produces a much greater percentage difference in the flux-density than
  in dynamos with long air-gaps. In toothed armatures with short
  air-gaps the shaft must on this account be sufficiently strong to
  withstand the stress without appreciable bending.


  The magnetic circuit.

Reference has already been made to the importance in dynamo design of
the _predetermination of the flux_ due to a given number of ampere-turns
wound on the field-magnet, or, conversely, of the number of ampere-turns
which must be furnished by the exciting coils in order that a certain
flux corresponding to one field may flow through the armature core from
each pole. An equally important problem is the correct proportioning of
the field-magnet, so that the useful flux Z_a may be obtained with the
greatest economy in materials and exciting energy. The key to the two
problems is to be found in the concept of a magnetic circuit as
originated by H.A. Rowland and R.H.M. Bosanquet;[16] and the full
solution of both may be especially connected with the name of Dr J.
Hopkinson, from his practical application of the concept in his design
of the Edison-Hopkinson machine, and in his paper on "Dynamo-Electric
Machinery."[17] The publication of this paper in 1886 begins the second
era in the history of the dynamo; it at once raised its design from the
level of empirical rules-of-thumb to a science, and is thus worthy to be
ranked as the necessary supplement of the original discoveries of
Faraday. The process of predetermining the necessary ampere-turns is
described in a simple case under ELECTROMAGNETISM. In its extension to
the complete dynamo, it consists merely in the division of the magnetic
circuit into such portions as have the same sectional area and
permeability and carry approximately the same total flux; the difference
of magnetic potential that must exist between the ends of each section
of the magnet in order that the flux may pass through it is then
calculated _seriatim_ for the several portions into which the magnetic
circuit is divided, and the separate items are summed up into one
magnetomotive force that must be furnished by the exciting coils.

[Illustration: FIG. 29.]

  The chief sections of the magnetic circuit are (1) the air-gaps, (2)
  the armature core, and (3) the iron magnet.

  The _air-gap_ of a dynamo with smooth-core armature is partly filled
  with copper and partly with the cotton, mica, or other materials used
  to insulate the core and wires; all these substances are, however,
  sensibly non-magnetic, so that the whole interferric gap between the
  iron of the pole-pieces and the iron of the armature may be treated as
  an air-space, of which the permeability is constant for all values of
  the flux density, and in the C.G.S. system is unity. Hence if l_g and
  A_g be the length and area of the single air-gap in cm. and sq. cm.,
  the reluctance of the double air-gap is 2l_g/A_g, and the difference
  of magnetic potential required to pass Z_a lines over this reluctance
  is Z_a·2l_g/A_g = B_g·2l_g; or, since one ampere-turn gives 1.257
  C.G.S. units of magnetomotive force, the exciting power in
  ampere-turns required over the two air-gaps is X_g = B_g·2l_g/1.257 =
  0.8 B_g·2l_g. In the determination of the area A_g small allowance
  must be made for the fringe of lines which extend beyond the actual
  polar face. In the toothed armature with open slots, the lines are no
  longer uniformly distributed over the air-gap area, but are graduated
  into alternate bands of dense and weak induction corresponding to the
  teeth and slots. Further, the lines curve round into the sides of the
  teeth, so that their average length of path in the air and the air-gap
  reluctance is not so easily calculated. Allowance must be made for
  this by taking an increased length of air-gap = ml_g, where m is the
  ratio _maximum density/mean density_, of which the value is chiefly
  determined by the ratios of the width of tooth to width of slot and of
  the width of slot to the air-gap between pole-face and surface of the
  armature core.

  The _armature core_ must be divided into the teeth and the core proper
  below the teeth. Owing to the tapering section of the teeth, the
  density rises towards their root, and when this reaches a high value,
  such as 18,000 or more lines per sq. cm., the saturation of the iron
  again forces an increasing proportion of the lines outwards into the
  slot. A distinction must then be drawn between the "apparent"
  induction which would hold if all the lines were concentrated in the
  teeth, and the "real" induction. The area of the iron is obtained by
  multiplying the number of teeth under the pole-face by their width and
  by the net length of the iron core parallel to the axis of rotation.
  The latter is the gross length of the armature less the space lost
  through the insulating varnish or paper between the disks or through
  the presence of ventilating ducts, which are introduced at intervals
  along the length of the core. The former deduction averages about 7 to
  10% of the gross length, while the latter, especially in large
  multipolar machines, is an even more important item. Alter calculating
  the density at different sections of the teeth, reference has now to
  be made to a (B, H) or flux-density curve, from which may be found the
  number of ampere-turns required per cm. length of path. This number
  may be expressed as a function of the density in the teeth, and f(B_t)
  be its average value over the length of a tooth, the ampere-turns of
  excitation required over the teeth on either side of the core as the
  lines of one field enter or leave the armature is X_t = f(B_t)·2l_t,
  where l_t is the length of a single tooth in cm.

  In the core proper below the teeth the length of path continually
  shortens as we pass from the middle of the pole towards the centre
  line of symmetry. On the other hand, as the lines gradually accumulate
  in the core, their density increases from zero midway under the poles
  until it reaches a maximum on the line of symmetry. The two effects
  partially counteract one another, and tend to equalize the difference
  of magnetic potential required over the paths of varying lengths; but
  since the reluctivity of the iron increases more rapidly than the
  density of the lines, we may approximately take for the length of path
  (l_a) the minimum peripheral distance between the edges of adjacent
  pole-faces, and then assume the maximum value of the density of the
  lines as holding throughout this entire path. In ring and drum
  machines the flux issuing from one pole divides into two halves in the
  armature core, so that the maximum density of lines in the armature is
  B_a = Z_a/2ab, where a = the radial depth of the disks in centimetres
  and b = the net length of iron core. The total exciting power required
  between the pole-pieces is therefore, at no load, X_p = X_g + X_t +
  X_a, where X_a = f(B_a)·l_a; in order, however, to allow for the
  effect of the armature current, which increases with the load, a
  further term X_b, must be added.

  [Illustration: Fig. 30.]

  In the continuous-current dynamo it may be, and usually is, necessary
  to move the brushes forward from the interpolar line of symmetry
  through a small angle in the direction of rotation, in order to avoid
  sparking between the brushes and the commutator (_vide infra_). When
  the dynamo is giving current, the wires on either side of the diameter
  of commutation form a current-sheet flowing along the surface of the
  armature from end to end, and whatever the actual end-connexions of
  the wires, the wires may be imagined to be joined together into a
  system of loops such that the two sides of each loop are carrying
  current in opposite directions. Thus a number of armature ampere-turns
  are formed, and their effect on the entire system of magnet and
  armature must be taken into account. So long as the diameter of
  commutation coincides with the line of symmetry, the armature may be
  regarded as a cylindrical electromagnet producing a flux of lines, as
  shown in fig. 30. The direction of the self-induced flux in the
  air-gaps is the same as that of the lines of the external field in one
  quadrant on one side of DC, but opposed to it in the other quadrant on
  the same side of DC; hence in the resultant field due to the combined
  action of the field-magnet and armature ampere-turns, the flux is as
  much strengthened over the one half of each polar face as it is
  weakened over the other, and the total number of lines is unaffected,
  although their distribution is altered. The armature ampere-turns are
  then called _cross-turns_, since they produce a cross-field, which,
  when combined with the symmetrical field, causes the leading
  pole-corners ll to be weakened and the trailing pole-corners tt to be
  strengthened, the neutral line of zero field being thus twisted
  forwards in the direction of rotation. But when the brushes and
  diameter of commutation are shifted forward, as shown in fig. 31, it
  will be seen that a number of ampere-turns, forming a zone between the
  lines Dn and mC, are in effect wound immediately on the magnetic
  circuit proper, and this belt of ampere-turns is in direct opposition
  to the ampere-turns of the field, as shown by the dotted and crossed
  wires on the pole-pieces. The armature ampere-turns are then divisible
  into the two bands, the _back-turns_, included within twice the angle
  of lead [lambda], weakening the field, and the cross-turns, bounded by
  the lines Dm, nC, again producing distortion of the weakened
  symmetrical field. If, therefore, a certain flux is to be passed
  through the armature core in opposition to the demagnetizing turns,
  the difference of magnetic potential between the pole-faces must
  include not only X_a, X_t, and X_g, but also an item X_b, in order to
  balance the "back" ampere-turns of the armature. The amount by which
  the brushes must be shifted forward increases with the armature
  current, and in corresponding proportion the back ampere-turns are
  also increased, their value being c[tau]2[lambda]/360°, where c = the
  current carried by each of the [tau] active wires. Thus the term X_b,
  takes into account the effect of the armature reaction on the total
  flux; it varies as the armature current and angle of lead required to
  avoid sparking are increased; and the reason for its introduction in
  the fourth place (X_p = X_g + X_t + X_a + X_b), is that it increases
  the magnetic difference of potential which must exist between the
  poles of the dynamo, and to which the greater part of the leakage is
  due. The leakage paths which are in parallel with the armature across
  the poles must now be estimated, and so a new value be derived for the
  flux at the commencement of the _iron-magnet_ path. If P = their joint
  permeance, the leakage flux due to the difference of potential at the
  poles is z_l = 1.257X_p × P, and this must be added to the useful flux
  Z_a, or Z_p = Z_a + Z_l. There are also certain leakage paths in
  parallel with the magnet cores, and upon the permeance of these a
  varying number of ampere-turns is acting as we proceed along the
  magnet coils; the magnet flux therefore increases by the addition of
  leakage along the length of the limbs, and finally reaches a maximum
  near the yoke. Either, then, the density in the magnet B_m = Z_m/A_m
  will vary if the same sectional area be retained throughout, or the
  sectional area of the magnet must itself be progressively increased.
  In general, sufficient accuracy will be obtained by assuming a certain
  number of additional leakage lines z_n as traversing the entire length
  of magnet limbs and yoke (= l_m), so that the density in the magnet
  has the uniform value B_m = (Z_p + z_n)/A_m. The leakage flux added on
  actually within the length of the magnet core or z_n will be
  approximately equal to half the total M.M.F. of the coils multiplied
  by the permeance of the leakage paths around one coil. The
  corresponding value of H can then be obtained from the (B, H) curve of
  the material of which the magnet is composed, and the ampere-turns
  thus determined must be added to X_p, or X = X_p + X_m, where X_m =
  f(B_m)l_m. The final equation for the exciting power required on a
  magnetic circuit as a whole will therefore take the form

    X = A[Tau] = 0.8B_g·2l_g + f(B_t)2l_t + f(B_a)l_a + X_b + f(B_m)l_m. (3)

  If the magnet cores are of wrought iron or cast steel, and the yoke is
  of cast iron, the last term must be divided into two portions
  corresponding to the different materials, i.e. into f(B_m)l_m +
  f(B_y)l_y. In the ordinary multipolar machine with as many
  magnet-coils as there are poles, each coil must furnish half the above
  number of ampere-turns.

  [Illustration: FIG. 31.]


    Magnetic leakage.

  Since no substance is impermeable to the passage of magnetic flux, the
  only form of magnetic circuit free from leakage is one uniformly wound
  with ampere-turns over its whole length. The reduction of the
  _magnetic leakage_ to a minimum in any given type is therefore
  primarily a question of distributing the winding as far as possible
  uniformly upon the circuit, and as the winding must be more or less
  concentrated into coils, it resolves itself into the necessity of
  introducing as long air-paths as possible between any surfaces which
  are at different magnetic potentials. No iron should be brought near
  the machine which does not form part of the magnetic circuit proper,
  and especially no iron should be brought near the poles, between which
  the difference of magnetic potential practically reaches its maximum
  value. In default of a machine of the same size or similar type on
  which to experiment, the probable direction of the leakage flux must
  be assumed from the drawing, and the air surrounding the machine must
  be mapped out into areas, between which the permeances are calculated
  as closely as possible by means of such approximate formulae as those
  devised by Professor G. Forbes.


    Excitation of field-magnet.

  In the earliest "magneto-electric" machines permanent steel magnets,
  either simple or compound, were employed, and for many years these
  were retained in certain alternators, some of which are still in use
  for arc lighting in lighthouses. But since the field they furnish is
  very weak, a great advance was made when they were replaced by soft
  iron electromagnets, which could be made to yield a much more intense
  flux. As early as 1831 Faraday[18] experimented with electromagnets,
  and after 1850 they gradually superseded the permanent magnet. When
  the total ampere-turns required to excite the electromagnet have been
  determined, it remains to decide how the excitation shall be obtained;
  and, according to the method adopted, continuous-current machines may
  be divided into four well-defined classes.

  [Illustration: FIG. 32.]

  The simplest method, and that which was first used, is _separate
  excitation_ from some other source of direct current, which may be
  either a primary or a secondary battery or another dynamo (fig. 32).
  But since the armature yields a continuous current, it was early
  suggested (by J. Brett in 1848 and F. Sinsteden in 1851) that this
  current might be utilized to increase the flux; combinations of
  permanent and electromagnets were therefore next employed, acting
  either on the main armature or on separate armatures, until in 1867 Dr
  Werner von Siemens and Sir C. Wheatstone almost simultaneously
  discovered that the dynamo could be made _self-exciting_ through the
  residual magnetism retained in the soft iron cores of the
  electromagnet. The former proposed to take the whole of the current
  round the magnet coils which were in series with the armature and
  external circuit, while the latter proposed to utilize only a portion
  derived by a shunt from the main circuit; we thus arrive at the second
  and third classes, namely, _series_ and _shunt_ machines. The starting
  of the process of excitation in either case is the same; when the
  brushes are touching the commutator and the armature is rotated, the
  small amount of flux left in the magnet is cut by the wires, and a
  very small current begins to flow round the closed circuit; this
  increases the flux, which in turn further increases the E.M.F. and
  current, until, finally, the cumulative effect stops through the
  increasing saturation of the iron cores. Fig. 33, illustrating the
  _series_ machine, shows the winding of the exciting coils to be
  composed of a few turns of thick wire. Since the current is undivided
  throughout the whole circuit, the resistance of both the armature and
  field-magnet winding must be low as compared with that of the external
  circuit, if the useful power available at the terminals of the machine
  is to form a large percentage of the total electrical power--in other
  words, if the efficiency is to be high. Fig. 34 shows the third
  method, in which the winding of the field-magnets is a _shunt_ or
  fine-wire circuit of many turns applied to the terminals of the
  machine; in this ease the resistance of the shunt must be high as
  compared with that of the external circuit, in order that only a small
  proportion of the total energy may be absorbed in the field.

  [Illustration: FIG. 33.]

  [Illustration: FIG. 34.]

  Since the whole of the armature current passes round the field-magnet
  of the series machine, any alteration in the resistance of the
  external circuit will affect the excitation and also the voltage. A
  curve connecting together corresponding values of external current and
  terminal voltage for a given speed of rotation is known as the
  _external-characteristic_ of the machine; in its main features it has
  the same appearance as a curve of magnetic flux, but when the current
  exceeds a certain amount it begins to bend downwards and the voltage
  decreases. The reason for this will be found in the armature reaction
  at large loads, which gradually produces a more and more powerful
  demagnetizing effect, as the brushes are shifted forwards to avoid
  sparking; eventually the back ampere-turns overpower any addition to
  the field that would otherwise be due to the increased current flowing
  round the magnet. The "external characteristic" for a shunt machine
  has an entirely different shape. The field-magnet circuit being
  connected in parallel with the external circuit, the exciting current,
  if the applied voltage remains the same, is in no way affected by
  alterations in the resistance of the latter. As, however, an increase
  in the external current causes a greater loss of volts in the armature
  and a greater armature reaction, the terminal voltage, which is also
  the exciting voltage, is highest at no load and then diminishes. The
  fall is at first gradual, but after a certain critical value of the
  armature current is reached, the machine is rapidly demagnetized and
  loses its voltage entirely.

  [Illustration: FIG. 35.]

  The last method of excitation, namely, _compound-winding_ (fig. 35),
  is a combination of the two preceding, and was first used by S.A.
  Varley and by C.F. Brush. If a machine is in the first instance
  shunt-wound, and a certain number of series-turns are added, the
  latter, since they carry the external current, can be made to
  counteract the effect which the increased external current would have
  in lowering the voltage of the simple shunt machine. The ampere-turns
  of the series winding must be such that they not only balance the
  increase of the demagnetizing back ampere-turns on the armature, but
  further increase the useful flux, and compensate for the loss of volts
  over their own resistance and that of the armature. The machine will
  then give for a constant speed a nearly constant voltage at its
  terminals, and the curve of the external characteristic becomes a
  straight line for all loads within its capacity. Since with most prime
  movers an increase of the load is accompanied by a drop in speed, this
  effect may also be counteracted; while, lastly, if the series-turns
  are still further increased, the voltage may be made to rise with an
  increasing load, and the machine is "over-compounded."


  Commutation and sparking at the brushes.

At the initial moment when an armature coil is first short-circuited by
the passage of the two sectors forming its ends under the contact
surface of a brush, a certain amount of electromagnetic energy is stored
up in its magnetic field as linked with the ampere-turns of the coil
when carrying its full share of the total armature current. During the
period of short-circuit this quantity of energy has to be dissipated as
the current falls to zero, and has again to be re-stored as the current
is reversed and raised to the same value, but in the opposite direction.
The period of short-circuit as fixed by the widths of the brush and of
the mica insulation between the sectors, and by the peripheral speed of
the commutator is extremely brief, and only lasts on an average from
(1/200)th to (1/1000)th of a second. The problem of sparkless
commutation is therefore primarily a question of our ability to
dissipate and to re-store the required amount of energy with sufficient
rapidity.

An important aid towards the solution of this problem is found in the
effect of the varying contact-resistance between the brush and the
surfaces of the leading and trailing sectors which it covers. As the
commutator moves under the brush, the area of contact which the brush
makes with the leading sector diminishes, and the resistance between the
two rises; conversely, the area of contact between the brush and the
trailing sector increases and the resistance falls. This action tends
automatically to bring the current through each sector into strict
proportionality to the amount of its surface which is covered by the
brush, and so to keep the current-density and the loss of volts over the
contacts uniform and constant. As soon as the current-density in the two
portions of the brush becomes unequal, a greater amount of heat is
developed at the commutator surface, and this in the first place affords
an additional outlet for the dissipation of the stored energy of the
coil, while after reversal of the current it is the accompaniment of a
re-storage of the required energy. This energy, as well as that which is
spent in heating the coil, can in fact, in default of other sources, be
derived through the action of the unequal current-density from the
electrical output of the rest of the armature winding, and so only
indirectly from the prime mover.

In practice, when the normal contact-resistance of the brushes is low
relatively to the resistance of the coil, as is the case with metal
brushes of copper or brass gauze, but little benefit can be obtained
from the action of the varying contact-resistance. It exerts no
appreciable effect until close towards the end of the period of
short-circuit, and then only with such a high-current-density at the
trailing edge of the leaving sector that at the moment of parting the
brush-tip is fused, or its metal volatilized, and sparking has in fact
set in. With such brushes, then, it becomes necessary to call in the aid
of a reversing E.M.F. impressed upon the coil by the magnetic field
through which it is moving. If such a reversing field comes into action
while the current is still unreversed, its E.M.F. is opposed to the
direction of the current, and the coil is therefore driving the armature
forward as in a motor; it thus affords a ready means of rapidly
dissipating part of the initial energy in the form of mechanical work
instead of as heat. After the current has been reversed, the converse
process sets in, and the prime mover directly expends mechanical energy
not only in heating the coil, but also in storing up electromagnetic
energy with a rapidity dependent upon the strength of the reversing
field. The required direction of external field can be obtained in the
dynamo by shifting the brushes forward, so that the short-circuited coil
enters into the fringe of lines issuing from the leading pole-tip, i.e.
by giving the brushes an "angle of lead." An objection to this process
is that the main flux is thereby weakened owing to the belt of back
ampere-turns which arises (_v. supra_). A still greater objection is
that the amount of the angle of lead must be suited to the value of the
load, the corrective power of copper brushes being very small if the
reversing E.M.F. is not closely adjusted in proportion to the armature
current.

On this account metal brushes have been almost entirely superseded by
carbon moulded into hard blocks. With these, owing to their higher
specific contact-resistance, a very considerable reversing effect can be
obtained through the action of unequal current-density, and indeed in
favourable cases complete sparklessness can be obtained throughout the
entire range of load of the machine with a fixed position of the
brushes. Yet if the work which they are called upon to perform exceeds
certain limits, they tend to become overheated with consequent glowing
or sparking at their tips, so that, wherever possible, it is advisable
to reinforce their action by a certain amount of reversing field, the
brushes being set so that its strength is roughly correct for, say, half
load.

In the case of dynamos driven by steam-turbines, sparkless commutation
is especially difficult to obtain owing to the high speed of rotation
and the very short space of time in which the current has to be
reversed. Special "reversing poles" then become necessary; these are
wound with magnetizing coils in series with the main armature current,
so that the strength of field which they yield is roughly proportional
to the current which has to be reversed. These again may be combined
with a "compensating winding" embedded in the pole-faces and carrying
current in the opposite direction to the armature ampere-turns, so as to
neutralize the cross effect of the latter and prevent distortion of the
resultant field.


    Heating effects.

  From the moment that a dynamo begins to run with excited field, heat
  is continuously generated by the passage of the current through the
  windings of the field-magnet coils and the armature, as well as by the
  action of hysteresis and eddy currents in the armature and
  pole-pieces. Whether the source of the heat be in the field-magnet or
  in the armature, the mass in which it originates will continue to rise
  in temperature until such a difference of temperature is established
  between itself and the surrounding air that the rate at which the heat
  is carried off by radiation, convection and conduction is equal to the
  rate at which it is being generated. Evidently, then, the temperature
  which any part of the machine attains after a prolonged run must
  depend on the extent and effectiveness of the cooling surface from
  which radiation takes place, upon the presence or absence of any
  currents of air set up by the rotation of itself or surrounding parts,
  and upon the presence of neighbouring masses of metal to carry away
  the heat by conduction. In the field-magnet coils the rate at which
  heat is being generated is easily determined, since it is equal to the
  square of the current passing through them multiplied by their
  resistance. Further, the magnet is usually stationary, and only
  indirectly affected by draughts of air due to the rotating armature.
  Hence for machines of a given type and of similar proportions, it is
  not difficult to decide upon some method of reckoning the cooling
  surface of the magnet coils S_c, such that the rise of temperature
  above that of the surrounding air may be predicted from an equation of
  the form t° = kW/S_c, where W = the rate in watts at which heat is
  generated in the coils, and k is some constant depending upon the
  exact method of reckoning their cooling surface. As a general rule the
  cooling surface of a field-coil is reckoned as equal to the exposed
  outer surface of its wire, the influence of the end flanges being
  neglected, or only taken into account in the case of very short
  bobbins wound with a considerable depth of wire. In the case of the
  rotating armature a similar formula must be constructed, but with the
  addition of a factor to allow for the increase in the effectiveness of
  any given cooling surface due to the rotation causing convection
  currents in the surrounding air. Only experiment can determine the
  exact effect of this, and even with a given type of armature it is
  dependent on the number of poles, each of which helps to break up the
  air-currents, and so to dissipate the heat. For example, in two-pole
  machines with drum bar-armatures, if the cooling surface be reckoned
  as equal to the cylindrical exterior plus the area of the two ends,
  the heating coefficient for a peripheral speed of 1500 ft. per minute
  is less than half of that for the same armature when at rest. A
  further difficulty still meets the designer in the correct
  predetermination of the total loss of watts in an armature before the
  machine has been tested. It is made up of three separate items,
  namely, the copper loss in the armature winding, the loss by
  hysteresis in the iron, and the loss by eddy currents, which again may
  be divided into those in the armature bars and end-connexions, and
  those in the core and its end-plates. The two latter items are both
  dependent upon the speed of the machine; but whereas the hysteresis
  loss is proportional to the speed for a given density of flux in the
  armature, the eddy current loss is proportional to the square of the
  speed, and owing to this difference, the one loss can be separated
  from the other by testing an armature at varying speeds. Thus for a
  given rise of temperature, the question of the amount of current which
  can be taken out of an armature at different speeds depends upon the
  proportion which the hysteresis and eddy watts bear to the copper
  loss, and the ratio in which the effectiveness of the cooling surface
  is altered by the alteration in speed. Experimental data, again, can
  alone decide upon the amount of eddy currents that may be expected in
  given armatures, and caution is required in applying the results of
  one machine to another in which any of the conditions, such as the
  number of poles, density in the teeth, proportions of slot depth to
  width, &c., are radically altered.

  It remains to add, that the rise of temperature which may be permitted
  in any part of a dynamo after a prolonged run is very generally placed
  at about 70° Fahr. above the surrounding air. Such a limit in ordinary
  conditions of working leads to a final temperature of about 170°
  Fahr., beyond which the durability of the insulation of the wires is
  liable to be injuriously affected. Upon some such basis the output of
  a dynamo in continuous working is rated, although for short periods
  of, say, two hours the normal full-load current of a large machine may
  be exceeded by some 25% without unduly heating the armature.


  Uses of continuous current dynamos.

For the electro-deposition of metals or the electrolytic treatment of
ores a continuous current is a necessity; but, apart from such use, the
purposes from which the continuous-current dynamo is well adapted are so
numerous that they cover nearly the whole field of electrical
engineering, with one important exception. To meet these various uses,
the pressures for which the machine is designed are of equally wide
range; for the transmission of power over long distances they may be as
high as 3000 volts, and for electrolytic work as low as five. Each
electrolytic bath, with its leads, requires on an average only some four
or five volts, so that even when several are worked in series the
voltage of the dynamo seldom exceeds 60. On the other hand, the current
is large and may amount to as much as from 1000 to 14,000 amperes,
necessitating the use of two commutators, one at either end of the
armature, in order to collect the current without excessive heating of
the sectors and brushes. The field-magnets are invariably shunt-wound,
in order to avoid reversal of the current through polarization at the
electrodes of the bath. For incandescent lighting by glow lamps, the
requirements of small isolated installations and of central stations for
the distribution of electrical energy over large areas must be
distinguished. For the lighting of a private house or small factory, the
dynamo giving from 5 to 100 kilo-watts of output is commonly wound for a
voltage of 100, and is driven by pulley and belt from a gas, oil or
steam-engine; or, if approaching the higher limit above mentioned, it is
often directly coupled to the crank-shaft of the steam-engine. If used
in conjunction with an accumulator of secondary cells, it is
shunt-wound, and must give the higher voltage necessary to charge the
battery; otherwise it is compound-wound, in order to maintain the
pressure on the lamps constant under all loads within its capacity. The
compound-wound dynamo is likewise the most usual for the lighting of
steamships, and is then directly coupled to its steam-engine; its output
seldom exceeds 100 kilo-watts, at a voltage of 100 or 110. For larger
installations a voltage of 250 is commonly used, while for
central-station work, economy in the distributing mains dictates a
higher voltage, especially in connexion with a three-wire system; the
larger dynamos may then give 500 volts, and be connected directly across
the two outer wires. A pair of smaller machines coupled together, and
each capable of giving 250 volts, are often placed in series across the
system, with their common junction connected to the middle wire; the one
which at any time is on the side carrying the smaller current will act
as a motor and drive the other as a dynamo, so as to balance the system.
The directly-coupled steam dynamo may be said to have practically
displaced the belt- or rope-driven sets which were formerly common in
central stations. The generating units of the central station are
arranged in progressive sizes, rising from, it may be, 250 or 500
horse-power up to 750 or 1000, or in large towns to as much as 5000
horse-power. If for lighting only, they are usually shunt-wound, the
regulation of the voltage, to keep the pressure constant on the
distributing system under the gradual changes of load, being effected by
variable resistances in the shunt circuit of the field-magnets.

Generators used for supplying current to electric tramways are commonly
wound for 500 volts at no load and are over-compounded, so that the
voltage rises to 550 volts at the maximum load, and thus compensates for
the loss of volts over the transmitting lines. For arc lighting it was
formerly usual to employ a class of dynamo which, from the nature of its
construction, was called an "open-coil" machine, and which gave a
unidirectional but pulsating current. Of such machines the Brush and
Thomson-Houston types were very widely used; their E.M.F. ranged from
2000 to 3000 volts for working a large number of arcs in series, and by
means of special regulators their current was maintained constant over a
wide range of voltage. But as their efficiency was low and they could
not be applied to any other purpose, they have been largely superseded
in central stations by closed-coil dynamos or alternators, which can
also be used for incandescent lighting. In cases where the central
station is situated at some distance from the district to which the
electric energy is to be supplied, voltages from 1000 to 2000 are
employed, and these are transformed down at certain distributing centres
by continuous-current transformers (see TRANSFORMERS and ELECTRICITY
SUPPLY). These latter machines are in reality motor-driven dynamos, and
hence are also called _motor-generators_; the armatures of the motor and
dynamo are often wound on the same core, with a commutator at either
end, the one to receive the high-pressure motor current, and the other
to collect the low-pressure current furnished by the dynamo.

  In all large central stations it is necessary that the dynamos should
  be capable of being run _in parallel_, so that their outputs may be
  combined on the same "omnibus bars" and thence distributed to the
  network of feeders. With simple shunt-wound machines this is easily
  effected by coupling together terminals of like sign when the voltage
  of the two or more machines are closely equal. With compound-wound
  dynamos not only must the external terminals of like sign be coupled
  together, but the junctions of the brush leads with the series winding
  must be connected by an "equalizing" lead of low resistance;
  otherwise, should the E.M.F. of one machine for any reason fall below
  the voltage of the omnibus bars, there is a danger of its polarity
  being reversed by a back current from the others with which it is in
  parallel.

  Owing to the necessary presence in the continuous-current dynamo of
  the commutator, with its attendant liability to sparking at the
  brushes, and further, owing to the difficulty of insulating the
  rotating armature wires, a pressure of 3000 volts has seldom been
  exceeded in any one continuous-current machine, and has been given
  above as the limiting voltage of the class. If therefore it is
  required to work with higher pressures in order to secure economy in
  the transmitting lines, two or more machines must be coupled _in
  series_ by connecting together terminals which are of unlike sign.[19]
  The stress of the total voltage may still fall on the insulation of
  the winding from the body of the machine; hence for high-voltage
  transmission of power over very long distances, the continuous-current
  dynamo in certain points yields in convenience to the alternator. In
  this there is no commutator, the armature coils may be stationary and
  can be more thoroughly insulated, while further, if it be thought
  undesirable to design the machine for the full transmitting voltage,
  it is easy to wind the armature for a low pressure; this can be
  subsequently transformed up to a high pressure by means of the
  alternating-current transformer, which has stationary windings and so
  high an efficiency that but little loss arises from its use. With
  these remarks, the transition may be made to the fuller discussion of
  the alternator.


_Alternators._

  Frequency.

The frequency employed in alternating-current systems for distributing
power and light varies between such wide limits as 25 and 133; yet in
recent times the tendency has been towards standard frequencies of 25,
50 and 100 as a maximum. High frequencies involve more copper in the
magnet coils, owing to the greater number of poles, and a greater loss
of power in their excitation, but the alternator as a whole is somewhat
lighter, and the transformers are cheaper. On the other hand, high
frequency may cause prejudicial effects, due to the inductance and
capacity of the distributing lines; and in asynchronous motors used on
polyphase systems the increased number of poles necessary to obtain
reasonable speeds reduces their efficiency, and is otherwise
disadvantageous, especially for small horse-powers. A frequency lower
than 40 is, however, not permissible where arc lighting is to form any
considerable portion of the work and is to be effected by the
alternating current without rectification, since below this value the
eye can detect the periodic alteration in the light as the carbons
alternately cool and become heated. Thus for combined lighting and power
50 or 60 are the most usual frequencies; but if the system is designed
solely or chiefly for the distribution of power, a still lower frequency
is preferable. On this account 25 was selected by the engineers for the
Niagara Falls power transmission, after careful consideration of the
problem, and this frequency has since been widely adopted in similar
cases.


  Alternator construction.

The most usual type of heteropolar alternator has an internal rotating
field-magnet system, and an external stationary armature, as in fig. 10.
The coils of the armature, which must for high voltages be heavily
insulated, are then not subjected to the additional stresses due to
centrifugal force; and further, the collecting rings which must be
attached to the rotating portion need only transmit the exciting current
at a low voltage.

[Illustration: FIG. 36.]

The homopolar machine possesses the advantages that only a single
exciting coil is required, whatever the number of polar projections, and
that both the armature and field-magnet coils may be stationary. From
fig. 8 it will be seen that it is not essential that the exciting coil
should revolve with the internal magnet, but it may be supported from
the external stationary armature while still embracing the central part
of the rotor. The E.M.F. is set up in the armature coils through the
periodic variation of the flux through them as the iron projections
sweep past, and these latter may be likened to a number of "keepers,"
which complete the magnetic circuit. From the action of the rotating
iron masses they may also be considered as the inducing elements or
"inductors," and the homopolar machine is thence also known as the
"inductor alternator." If the end of the rotor marked S in fig. 8 is
split up into a number of S polar projections similar to the N poles, a
second set of armature coils may be arranged opposite to them, and we
obtain an inductor alternator with double armature. Or the polar
projections at the two ends may be staggered, and a single armature
winding be passed straight through the armature, as in fig. 36, which
shows at the side the appearance of the revolving inductor with its
crown of polar projections in one ring opposite to the gaps between the
polar projections of the other ring. But in spite of its advantage of
the single stationary exciting coil, the inductor alternator has such a
high degree of leakage, and the effect of armature reaction is so
detrimental in it, that the type has been gradually abandoned, and a
return has been almost universally made to the heteropolar alternator
with internal poles radiating outwards from a circular yoke-ring. The
construction of a typical machine of this class is illustrated in fig.
37.

[Illustration: FIG. 37.]

Since the field-magnet coils rotate, they must be carefully designed to
withstand centrifugal force, and are best composed of flat copper strip
wound on edge with thin insulation between adjacent layers. The coil is
secured by the edges of the pole-shoes which overhang the pole and
tightly compress the coil against the yoke-ring; the only effect from
centrifugal force is then to compress still further the flat turns of
copper against the pole-shoes without deformation. The poles are either
of cast steel of circular or oblong section, bolted to the rim of the
yoke-ring, or are built up of thin laminations of sheet steel. When the
peripheral speed is very high, the yoke-ring will be of cast steel or
may itself be built up of sheet steel laminations, this material being
reliable and easily tested to ensure its sound mechanical strength. If
the armature slots are open, the pole-pieces will in any case be
laminated to reduce the eddy currents set up by the variation of the
flux-density.

Owing to the great number of poles[20] of the alternator when driven by
a reciprocating steam-engine, the diameter of its rotor is usually
larger and its length less than in the continuous-current dynamo of
corresponding output. The support of the armature core when of large
diameter is therefore a more difficult problem, since, apart from any
magnetic strains to which it may be subjected, its own weight tends to
deform it. The segmental core-disks are usually secured to the internal
circumference of a circular cast iron frame; the latter has a box
section of considerable radial depth to give stiffness to it, and the
disks are tightly clamped between internal flanges, one being a fixed
part of the frame and the other loose, with transverse bolts passing
right through from side to side (fig. 37). In order to lessen the weight
of the structure and its expense in material, the cast iron frame has in
some cases been entirely dispensed with, and braced tie-rods have been
used to render the effective iron of the armature core-disks
self-supporting.

[Illustration: FIG. 38.]

Owing to the high speed of the turbo-alternator, its rotor calls for the
utmost care in its design to withstand the effect of centrifugal force
without any shifting of the exciting coils, and to secure a perfect
balance.

The appearance of the armature of a typical three-phase alternator is
illustrated in fig. 38, which shows a portion of the lower half after
removal of the field-magnet.

With open slots the coils, after being wound on formers to the required
shape, are thoroughly impregnated with insulating compound, dried, and
after a further wrapping with several layers of insulating material,
finally pressed into the slots together with a sheet of leatheroid or
flexible micanite. The end-connexions of each group of coils of one
phase project straight out from the slots or are bent upwards
alternately with those of the other phases, so that they may clear one
another (fig. 37). A wooden wedge driven into a groove at the top of
each slot is often used to lock the coil in place. With slots nearly
closed at the top, the coils are formed by hand by threading the wire
through tubes of micanite or specially prepared paper lining the slots;
or with single-turn loops, stout bars of copper of [U]-shape can be
driven through the slots and closed by soldered connexions at the other
end.


    Shape of E.M.F. curve.

  The first experimental determination of the shape of the E.M.F. curve
  of an alternator was made by J. Joubert in 1880. A revolving
  contact-maker charged a condenser with the E.M.F. produced by the
  armature at a particular instant during each period. The condenser was
  discharged through a ballistic galvanometer, and from the measured
  throw the instantaneous E.M.F. could be deduced. The contact-maker was
  then shifted through a small angle, and the instantaneous E.M.F. at
  the new position corresponding to a different moment in the period was
  measured; this process was repeated until the E.M.F. curve for a
  complete period could be traced. Various modifications of the same
  principle have since been used, and a form of "oscillograph" (q.v.)
  has been perfected which is well adapted for the purpose of tracing
  the curves both of E.M.F. and of current. The machine on which Joubert
  carried out his experiments was a Siemens disk alternator having no
  iron in its armature, and it was found that the curve of E.M.F. was
  practically identical with a sine curve. The same law has also been
  found to hold true for a smooth-core ring or drum armature, but the
  presence of the iron core enables the armature current to produce
  greater distorting effect, so that the curves under load may vary
  considerably from their shape at no load. In toothed armatures, the
  broken surface of the core, and the still greater reaction from the
  armature current, may produce wide variations from the sine law, the
  general tendency being to give the E.M.F. curve a more peaked form.
  The great convenience of the assumption that the E.M.F. obeys the sine
  law has led to its being very commonly used as the basis for the
  mathematical analysis of alternator problems; but any deductions made
  from this premiss require to be applied with caution if they are
  likely to be modified by a different shape of the curve. Further, the
  same alternator will give widely different curves even of E.M.F., and
  still more so of current, according to the nature of the external
  circuit to which it is connected. As will be explained later, the
  phase of the current relatively to the E.M.F. depends not only on the
  inductance of the alternator itself, but also upon the inductance and
  capacity of the external circuit, so that the same current will
  produce different effects according to the amount by which it lags or
  leads. The question as to the relative advantages of differently
  shaped E.M.F. curves has led to much discussion, but can only be
  answered by reference to the nature of the work that the alternator
  has to do--i.e. whether it be arc lighting, motor driving, or
  incandescent lighting through transformers. The shape of the E.M.F.
  curve is, however, of great importance in one respect, since upon it
  depends the ratio of the maximum instantaneous E.M.F. to the effective
  value, and the insulation of the entire circuit, both external and
  internal, must be capable of withstanding the maximum E.M.F. While the
  maximum value of the sine curve is [root]2 or 1.414 times the
  effective value, the maximum value of a [Lambda] curve is 1.732 times
  the effective value, so that for the same effective E.M.F. the
  armature wires must not only be more heavily insulated than in the
  continuous-current dynamo, but also the more peaked the curve the
  better must be the insulation.


    Excitation.

  Since an alternating current cannot be used for exciting the
  field-magnet, recourse must be had to some source of a direct current.
  This is usually obtained from a small auxiliary continuous-current
  dynamo, called an _exciter_, which may be an entirely separate
  machine, separately driven and used for exciting several alternators,
  or may be driven from the alternator itself; in the latter case the
  armature of the exciter is often coupled directly to the rotating
  shaft of the alternator, while its field-magnet is attached to the
  bed-plate. Although separate excitation is the more usual method, the
  alternator can also be made self-exciting if a part or the whole of
  the alternating current is "rectified," and thus converted into a
  direct current.


    Quarter-phase alternators.

  The general idea of the polyphase alternator giving two or more
  E.M.F.'s of the same frequency, but displaced in phase, has been
  already described. The several phases may be entirely independent, and
  such was the case with the early polyphase machines of Gramme, who
  used four independent circuits, and also in the large two-phase
  alternators designed by J.E.H. Gordon in 1883. If the phases are thus
  entirely separate, each requires two collector rings and two wires to
  its external circuit, i.e. four in all for two-phase and six for
  three-phase machines. The only advantage of the polyphase machine as
  thus used is that the whole of the surface of the armature core may be
  efficiently covered with winding, and the output of the alternator for
  a given size be thereby increased. It is, however, also possible so to
  interlink the several circuits of the armature that the necessary
  number of transmitting lines to the external circuits may be reduced,
  and also the weight of copper in them for a given loss in the
  transmission.[21] The condition which obviously must be fulfilled,
  for such interlinking of the phases to be possible, is that in the
  lines which are to meet at any common junction the algebraic sum of
  the instantaneous currents, reckoned as positive if away from such
  junction and as negative if towards it, must be zero. Thus if the
  phases be diagrammatically represented by the relative angular
  position of the coils in fig. 39, the current in the coils A and B
  differs in phase from the current in the coils C and D by a quarter of
  a period or 90°; hence if the two wires b and d be replaced by the
  single wire bd, this third wire will serve as a common path for the
  currents of the two phases either outwards or on their return. At any
  instant the value of the current in the third wire must be the vector
  sum of the two currents in the other wires, and if the shape of the
  curves of instantaneous E.M.F. and current are identical, and are
  assumed to be sinusoidal, the effective value of the current in the
  third wire will be the vector sum of the effective values of the
  currents in the other wires; in other words, if the system is
  balanced, the effective current in the third wire is [root]2, or 1.414
  times the current in either of the two outer wires. Since the currents
  of the two phases do not reach their maximum values at the same time,
  the sectional area of the third wire need not be twice that of the
  others; in order to secure maximum efficiency by employing the same
  current density in all three wires, it need only be 40% greater than
  that of either of the outer wires. The effective voltage between the
  external leads may in the same way be calculated by a vector diagram,
  and with the above _star connexion_ the voltage between the outer pair
  of wires a and c is [root]2, or 1.414 times the voltage between either
  of the outer wires and the common wire bd. Next, if the four coils are
  joined up into a continuous helix, just as in the winding of a
  continuous-current machine, four wires may be attached to equidistant
  points at the opposite ends of two diameters at right angles to each
  other (fig. 40). Such a method is known as the _mesh connexion_, and
  gives a perfectly symmetrical four-phase system of distribution. Four
  collecting rings are necessary if the armature rotates, and there is
  no saving in copper in the transmitting lines; but the importance of
  the arrangement lies in its use in connexion with rotary converters,
  in which it is necessary that the winding of the armature should form
  a closed circuit. If e = the effective voltage of one phase A, the
  voltage between any pair of adjacent lines in the diagram is e, and
  between m and o or n and p is e [root]2. The current in any line is
  the resultant of the currents in the two phases connected to it, and
  its effective value is c [root]2, where c is the current of one phase.

  [Illustration: FIG. 39.]

  [Illustration: FIG. 40.]

  [Illustration: FIG. 41.]


    Three-phase alternators.

  When we pass to machines giving three phases differing by 120°, the
  same methods of star and mesh connexion find their analogies. If the
  current in coil A (fig. 41) is flowing away from the centre, and has
  its maximum value, the currents in coils B and C are flowing towards
  the centre, and are each of half the magnitude of the current in A;
  the algebraic sum of the currents is therefore zero, and this will
  also be the case for all other instants. Hence the three coils can be
  united together at the centre, and three external wires are alone
  required. In this star or "Y" connexion, if e be the effective voltage
  of each phase, or the voltage between any one of the three collecting
  rings and the common connexion, the volts between any pair of
  transmitting lines will be E = e [root]3 (fig. 41); if the load be
  balanced, the effective current C in each of the three lines will be
  equal, and the total output in watts will be W = 3Ce = 3CE/[root]3 =
  1.732 EC, or 1.732 times the product of the effective voltage between
  the lines and the current in any single line. Next, if the three coils
  are closed upon themselves in a mesh or _delta_ fashion (fig. 42), the
  three transmitting wires may be connected to the junctions of the
  coils (by means of collecting rings if the armature rotates). The
  voltage E between any pair of wires is evidently that generated by
  one phase, and the current in a line wire is the resultant of that in
  two adjacent phases; or in a balanced system, if c be the current in
  each phase, the current in the line wire beyond a collecting ring is C
  = c [root]3, hence the watts are W = 3cE = 3CE/[root]3 = 1.732 EC, as
  before. Thus any three-phase winding may be changed over from the star
  to the delta connexion, and will then give 1.732 times as much
  current, but only 1/1.732 times the voltage, so that the output
  remains the same.

  [Illustration: FIG. 42.]


    Armature reaction in alternators

  The "armature reaction" of the alternator, when the term is used in
  its widest sense to cover all the effects of the alternating current
  in the armature as linked with a magnetic circuit or circuits, may be
  divided into three items which are different in their origin and
  consequences. In the first place the armature current produces a
  self-induced flux in local circuits independent of the main magnetic
  circuit, as e.g. linked with the ends of the coils as they project
  outwards from the armature core; such lines may be called "secondary
  leakage," of which the characteristic feature is that its amount is
  independent of the position of the coils relatively to the poles. The
  alternations of this flux give rise to an inductive voltage lagging
  90° behind the phase of the current, and this leakage or reactance
  voltage must be directly counterbalanced electrically by an equal
  component in the opposite sense in the voltage from the main field.
  The second and third elements are more immediately magnetic and are
  entirely dependent upon the position of the coils in relation to the
  poles and in relation to the phase of the current which they then
  carry. When the side of a drum coil is immediately under the centre of
  a pole, its ampere-turns are cross-magnetizing, i.e. produce a
  distortion of the main flux, displacing its maximum density to one or
  other edge of the pole. When the coil-side is midway between the poles
  and the axes of coil and pole coincide, the coil stands exactly
  opposite to the pole and embraces the same magnetic circuit as the
  field-magnet coils; its turns are therefore directly magnetizing,
  either weakening or strengthening the main flux according to the
  direction of the current. In intermediate positions the ampere-turns
  of the coil gradually pass from cross to direct and vice versa. When
  the instantaneous values of either the cross or direct magnetizing
  effect are integrated over a period and averaged, due account being
  taken of the number of slots per coil-side and of the different phases
  of the currents in the polyphase machine, expressions are obtained for
  the equivalent cross and direct ampere-turns of the armature as acting
  upon a pair of poles. For a given winding and current, the determining
  factor in either the one or the other is found to be the relative
  phase angle between the axis of a coil in its position when carrying
  the maximum current and the centre of a pole, the transverse reaction
  being proportional to the cosine of this angle, and the direct
  reaction to its sine. If the external circuit is inductive, the
  maximum value of the current lags behind the E.M.F. and so behind the
  centre of the pole; such a negative angle of lag causes the direct
  magnetizing turns to become back turns, directly weakening the main
  field and lowering the terminal voltage. Thus, just as in the
  continuous-current dynamo, for a given voltage under load the
  excitation between the pole-pieces X_p must not only supply the net
  excitation required over the air-gaps, armature core and teeth, but
  must also balance the back ampere-turns X_b of the armature.

  Evidently therefore the characteristic curve connecting armature
  current and terminal volts will with a constant exciting current
  depend on the nature of the load, whether inductive or non-inductive,
  and upon the amount of inductance already possessed by the armature
  itself. With an inductive load it will fall more rapidly from its
  initial maximum value, or, conversely, if the initial voltage is to be
  maintained under an increasing load, the exciting current will have to
  be increased more than if the load were non-inductive. In practical
  working many disadvantages result from a rapid drop of the terminal
  E.M.F. under increasing load, so that between no load and full load
  the variation in terminal voltage with constant excitation should not
  exceed 15%. Thus the output of an alternator is limited either by its
  heating or by its armature reaction, just as is the output of a
  continuous-current dynamo; in the case of the alternator, however, the
  limit set by armature reaction is not due to any sparking at the
  brushes, but to the drop in terminal voltage as the current is
  increased, and the consequent difficulty in maintaining a constant
  potential on the external circuit.


    The coupling of alternators.

  The joint operation of several alternators so that their outputs may
  be delivered into the same external circuit is sharply distinguished
  from the corresponding problem in continuous-current dynamos by the
  necessary condition that they must be in synchronism, i.e. not only
  must they be so driven that their frequency is the same, but their
  E.M.F.'s must be in phase or, as it is also expressed, the machines
  must be in step. Although in practice it is impossible to run two
  alternators in series unless they are rigidly coupled together--which
  virtually reduces them to one machine--two or more machines can be run
  in parallel, as was first described by H. Wilde in 1868 and
  subsequently redemonstrated by J. Hopkinson and W.G. Adams in 1884.
  Their E.M.F.'s should be as nearly as possible in synchronism, but,
  as contrasted with series connexion, parallel coupling gives them a
  certain power of recovery if they fall out of step, or are not in
  exact synchronism when thrown into parallel. In such circumstances a
  synchronizing current passes between the two machines, due to the
  difference in their instantaneous pressures; and as this current
  agrees in phase more nearly with the leading than with the lagging
  machine, the former machine does work as a generator on the latter as
  a motor. Hence the lagging machine is accelerated and the leading
  machine is retarded, until their frequencies and phase are again the
  same.


  Uses of alternators.

The chief use of the alternator has already been alluded to. Since it
can be employed to produce very high pressures either directly or
through the medium of transformers, it is specially adapted to the
electrical transmission of energy over long distances.[22] In the early
days of electric lighting, the alternate-current system was adopted for
a great number of central stations; the machines, designed to give a
pressure of 2000 volts, supplied transformers which were situated at
considerable distances and spread over large areas, without an undue
amount of copper in the transmitting lines. While there was later a
tendency to return to the continuous current for central stations, owing
to the introduction of better means for economizing the weight of copper
in the mains, the alternating current again came into favour, as
rendering it possible to place the central station in some convenient
site far away from the district which it was to serve. The pioneer
central station in this direction was the Deptford station of the London
Electric Supply Corporation, which furnished current to the heart of
London from a distance of 7 m. In this case, however, the alternators
were single-phase and gave the high pressure of 10,000 volts
immediately, while more recently the tendency has been to employ step-up
transformers and a polyphase system. The advantage of the latter is that
the current, after reaching the distant sub-stations, can be dealt with
by rotary converters, through which it is transformed into a continuous
current. The alternator is also used for welding, smelting in electric
furnaces, and other metallurgical processes where heating effects are
alone required; the large currents needed therein can be produced
without the disadvantage of the commutator, and, if necessary,
transformers can be interposed to lower the voltage and still further
increase the current. The alternating system can thus meet very various
needs, and its great recommendation may be said to lie in the
flexibility with which it can supply electrical energy through
transformers at any potential, or through rotary converters in
continuous-current form.

  AUTHORITIES.--For the further study of the dynamo, the following may
  be consulted, in addition to the references already given:--

  _General_: S.P. Thompson, _Dynamo-Electric
  Machinery--Continuous-Current Machines_ (1904), _Alternating-Current
  Machinery_ (1905, London); G. Kapp, _Dynamos, Alternators and
  Transformers_ (London, 1893); _Id., Electric Transmission of Energy_
  (London, 1894); Id., _Dynamo Construction; Electrical and Mechanical_
  (London, 1899); H.F. Parshall and H.M. Hobart, _Electric Generators_
  (London, 1900); C.C. Hawkins and F. Wallis, _The Dynamo_ (London,
  1903); E. Arnold, _Konstruktionstafeln für den Dynamobau_ (Stuttgart,
  1902); C.P. Steinmetz, _Elements of Electrical Engineering_ (New York,
  1901).

  _Continuous-Current Dynamos_: J. Fischer-Hinnen, _Continuous-Current
  Dynamos_ (London, 1899); E. Arnold, _Die Gleichstrommaschine_ (Berlin,
  1902); F. Niethammer, _Berechnung und Konstruktion der
  Gleichstrommaschinen und Gleichstrommotoren_ (Stuttgart, 1904).

  _Alternators_: D.C. Jackson and J.P. Jackson, _Alternating Currents
  and Alternating Current Machinery_ (New York, 1903); J.A. Fleming,
  _The Alternate Current Transformer_ (London, 1899); C.P. Steinmetz,
  _Alternating Current Phenomena_ (New York, 1900); E. Arnold, _Die
  Wechselstromtechnik_ (Berlin, 1904); S.P. Thompson, _Polyphase
  Electric Currents_ (London, 1900); A. Stewart, _Modern Polyphase
  Machinery_ (London, 1906); M. Oudin, _Standard Polyphase Apparatus and
  Systems_ (New York, 1904).     (C. C. H.)


FOOTNOTES:

  [1] _Experimental Researches in Electricity_, series ii. § 6, pars.
    256, 259-260, and series xxviii. § 34.

  [2] _Ibid._ series i. § 4, pars. 84-90.

  [3] "On the Physical Lines of Magnetic Force," _Phil. Mag._, June
    1852.

  [4] Faraday, _Exp. Res._ series xxviii. § 34, pars. 3104, 3114-3115.

  [5] _Id._, ib. series i. § 4, pars. 114-119.

  [6] _Id._, ib. series ii. § 6, pars. 211, 213; series xxviii. § 34,
    par. 3152.

  [7] Invented by Nikola Tesla (_Elec. Eng._ vol. xiii. p. 83. Cf.
    Brit. Pat. Spec. Nos. 2801 and 2812, 1894). Several early inventors,
    e.g. Salvatore dal Negro in 1832 (_Phil. Mag._ third series, vol. i.
    p. 45), adopted reciprocating or oscillatory motion, and this was
    again tried by Edison in 1878.

  [8] The advantage to be obtained by making the poles closely embrace
    the armature core was first realized by Dr Werner von Siemens in his
    "shuttle-wound" armature (Brit. Pat. No. 2107, 1856).

  [9] _Nuovo Cimento_ (1865), 19, 378.

  [10] Brit. Pat. No. 1668 (1870); _Comptes rendus_ (1871), 73, 175.

  [11] _Ann. Chim. Phys._ l. 322.

  [12] Ibid. li. 76. Since in H. Pixii's machine the armature was
    stationary, while both magnet and commutator rotated, four brushes
    were used, and the arrangement was not so simple as the split-ring
    described above, although the result was the same. J. Saxton's
    machine (1833) and E.M. Clarke's machine (1835, see Sturgeon's
    _Annals of Electricity_, i. 145) were similar to one another in that
    a unidirected current was obtained by utilizing every alternate
    half-wave of E.M.F., but the former still employed mercury collecting
    cups, while the latter employed metal brushes. W. Sturgeon in 1835
    followed Pixii in utilizing the entire wave of E.M.F., and abandoned
    the mercury cups in favour of metal brushes pressing on four
    semicircular disks (_Scientific Researches_, p. 252). The simple
    split-ring is described by Sir C. Wheatstone and Sir W.F. Cooke in
    their Patent No. 8345 (1840).

  [13] By the "leading" side of the tooth or of an armature coil or
    sector is to be understood that side which first enters under a pole
    after passing through the interpolar gap, and the edge of the pole
    under which it enters is here termed the "leading" edge as opposed to
    the "trailing" edge or corner from under which a tooth or coil
    emerges into the gap between the poles; cf. fig. 30, where the
    leading and trailing pole-corners are marked ll and tt.

  [14] Such was the arrangement of Wheatstone's machine (Brit. Pat. No.
    9022) of 1841, which was the first to give a more nearly "continuous"
    current, the number of sections and split-rings being five.

  [15] Its development from the split-ring was due to Pacinotti and
    Gramme (Brit. Pat. No. 1668, 1870) in connexion with their ring
    armatures.

  [16] And extended by G. Kapp, "On Modern Continuous-Current
    Dynamo-Electric Machines," _Proc. Inst. C.E._ vol. lxxxiii. p. 136.

  [17] Drs J. and E. Hopkinson, "Dynamo-Electric Machinery," Phil.
    Trans., May 6, 1886; this was further expanded in a second paper on
    "Dynamo-Electric Machinery," _Proc. Roy. Soc._, Feb. 15, 1892, and
    both are reprinted in _Original Papers on Dynamo-Machinery and Allied
    Subjects_.

  [18] _Exp. Res._, series i. § 4, par. 111. In 1845 Wheatstone and
    Cooke patented the use of "voltaic" magnets in place of permanent
    magnets (No. 10,655).

  [19] Between Moutiers and Lyons, a distance of 115 m., energy is
    transmitted on the Thury direct-current system at a maximum pressure
    of 60,000 volts. Four groups of machines in series are employed, each
    group consisting of four machines in series; the rated output of each
    component machine is 75 amperes at 3900 volts or 400 h.p. A water
    turbine drives two pairs of such machines through an insulating
    coupling, and the sub-base of each pair of machines is separately
    insulated from earth, the foundation being also of special insulating
    materials.

  [20] For experiments on high-frequency currents, Nikola Tesla
    constructed an alternator having 384 poles and giving a frequency of
    about 10,000 (_Journ. Inst. Elec. Eng._ 1892, 21, p. 82). The
    opposite extreme is found in alternators directly coupled to the
    Parsons steam-turbine, in which, with a speed of 3000 revs. per min.,
    only two poles are required to give a frequency of 50. By a
    combination of a Parsons steam-turbine running at 12,000 revs. per
    min. with an alternator of 140 poles a frequency of 14,000 has been
    obtained (_Engineering_, 25th of August 1899). For description of an
    experimental machine for 10,000 cycles per second when running at
    3000 revs. per min., see _Trans. Amer. Inst. Elect. Eng._ vol. xxiii.
    p. 417.

  [21] As in the historical transmission of energy from Lauffen to
    Frankfort (1891).

  [22] In the pioneer three-phase transmission between Laufen and
    Frankfort (_Electrician_, vol. xxvi. p. 637, and xxvii. p. 548), the
    three-phase current was transformed up from about 55 to 8500 volts,
    the distance being 110 m. A large number of installations driven by
    water power are now at work, in which energy is transmitted on the
    alternating-current system over distances of about 100 m. at
    pressures ranging from 20,000 to 67,000 volts.



DYNAMOMETER (Gr. [Greek: dynamis], strength, and [Greek: metron], a
measure), an instrument for measuring force exerted by men, animals and
machines. The name has been applied generally to all kinds of
instruments used in the measurement of a force, as for example electric
dynamometers, but the term specially denotes apparatus used in connexion
with the measurement of work, or in the measurement of the horse-power
of engines and motors. If P represent the average value of the component
of a force in the direction of the displacement, s, of its point of
application, the product Ps measures the work done during the
displacement. When the force acts on a body free to turn about a fixed
axis only, it is convenient to express the work done by the transformed
product T[theta], where T is the average turning moment or torque acting
to produce the displacement [theta] radians. The apparatus used to
measure P or T is the dynamometer. The factors s or [theta] are observed
independently. Apparatus is added to some dynamometers by means of which
a curve showing the variations of P on a distance base is drawn
automatically, the area of the diagram representing the work done; with
others, integrating apparatus is combined, from which the work done
during a given interval may be read off directly. It is convenient to
distinguish between absorption and transmission dynamometers. In the
first kind the work done is converted into heat; in the second it is
transmitted, after measurement, for use.

  _Absorption Dynamometers._--Baron Prony's dynamometer (_Ann. Chim.
  Phys._ 1821, vol. 19), which has been modified in various ways,
  consists in its original form of two symmetrically shaped timber beams
  clamped to the engine-shaft. When these are held from turning, their
  frictional resistance may be adjusted by means of nuts on the screwed
  bolts which hold them together until the shaft revolves at a given
  speed. To promote smoothness of action, the rubbing surfaces are
  lubricated. A weight is moved along the arm of one of the beams until
  it just keeps the brake steady midway between the stops which must be
  provided to hold it when the weight fails to do so. The general theory
  of this kind of brake is as follows:-Let F be the whole frictional
  resistance, r the common radius of the rubbing surfaces, W the force
  which holds the brake from turning and whose line of action is at a
  perpendicular distance R from the axis of the shaft, N the revolutions
  of the shaft per minute, [omega] its angular velocity in radians per
  second; then, assuming that the adjustments are made so that the
  engine runs steadily at a uniform speed, and that the brake is held
  still, clear of the stops and without oscillation, by W, the torque T
  exerted by the engine is equal to the frictional torque Fr acting at
  the brake surfaces, and this is measured by the statical moment of the
  weight W about the axis of revolution; that is--

    T = Fr = WR.  (1)

  Hence WR measures the torque T.

  If more than one force be applied to hold the brake from turning, Fr,
  and therefore T, are measured by the algebraical sum of their
  individual moments with respect to the axis. If the brake is not
  balanced, its moment about the axis must be included. Therefore, quite
  generally,

    T = [Sigma]WR.  (2)

  The factor [theta] of the product T[theta] is found by means of a
  revolution counter. The power of a motor is measured by the rate at
  which it works, and this is expressed by T[omega] = T2[pi]N/60 in
  foot-pounds per second, or T2[pi]N/33,000 in horse-power units. The
  latter is commonly referred to as the "brake horse-power." The
  maintenance of the conditions of steadiness implied in equation (1)
  depends upon the constancy of F, and therefore of the coefficient of
  friction µ between the rubbing surfaces. The heating at the surfaces,
  the variations in their smoothness, and the variations of the
  lubrication make [mu] continuously variable, and necessitate frequent
  adjustment of W or of the nuts. J.V. Poncelet (1788-1867) invented a
  form of Prony brake which automatically adjusted its grip as [mu]
  changed, thereby maintaining F constant.

  The principle of the compensating brake devised by J.G. Appold
  (1800-1865) is shown in fig. 1. A flexible steel band, lined with wood
  blocks, is gripped on the motor fly-wheel or pulley by a screw A,
  which, together with W, is adjusted to hold the brake steady.
  Compensation is effected by the lever L inserted at B. This has a
  slotted end, engaged by a pin P fixed to the framing, and it will be
  seen that its action is to slacken the band if the load tends to rise
  and to tighten it in the contrary case. The external forces holding
  the brake from turning are W, distant R from the axis, and the
  reaction, W1 say, of the lever against the fixed pin P, distant R1
  from the axis. The moment of W1 may be positive or negative. The
  torque T at any instant of steady running is therefore {WR ± W1R1}.

  [Illustration: FIG. 1.]

  Lord Kelvin patented a brake in 1858 (fig. 2) consisting of a rope or
  cord wrapped round the circumference of a rotating wheel, to one end
  of which is applied a regulated force, the other end being fixed to a
  spring balance. The ropes are spaced laterally by the blocks B, B, B,
  B, which also serve to prevent them from slipping sideways. When the
  wheel is turning in the direction indicated, the forces holding the
  band still are W, and p, the observed pull on the spring balance. Both
  these forces usually act at the same radius R, the distance from the
  axis to the centre line of the rope, in which case the torque T is (W
  - p)R, and consequently the brake horse-power is

    (W - p)R × 2[pi]N
    -----------------.
          33,000

  When µ changes the weight W rises or falls against the action of the
  spring balance until a stable condition of running is obtained. The
  ratio {W/p} is given by e^{µ[theta]}, where e = 2.718; µ is the
  coefficient of friction and [theta] the angle, measured in radians,
  subtended by the arc of contact between the rope and the wheel. In
  fig. 2 [theta] = 2[pi]. The ratio W/p increases very rapidly as
  [theta] is increased, and therefore, by making [theta] sufficiently
  large, p may conveniently be made a small fraction of W, thereby
  rendering errors of observation of the spring balance negligible. Thus
  this kind of brake, though cheap to make, is, when [theta] is large
  enough, an exceedingly accurate measuring instrument, readily applied
  and easily controlled. It has come into very general use in recent
  years, and has practically superseded the older forms of block brakes.

  [Illustration: FIG. 2.]

  It is sometimes necessary to use water to keep the brake wheel cool.
  Engines specially designed for testing are usually provided with a
  brake wheel having a trough-shaped rim. Water trickles continuously
  into the trough, and the centrifugal action holds it as an inside
  lining against the rim, where it slowly evaporates.

  Fig. 3 shows a band-brake invented by Professor James Thomson,
  suitable for testing motors exerting a constant torque (see
  _Engineering_, 22nd October 1880). To maintain e^{µ[theta]} constant,
  compensation for variation of [mu] is made by inversely varying
  [theta]. A and B are fast and loose pulleys, and the brake band is
  placed partly over the one and partly over the other. Weights W and w
  are adjusted to the torque. The band turns with the fast pulley if
  [mu] increase, thereby slightly turning the loose pulley, otherwise at
  rest, until [theta] is adjusted to the new value of [mu]. This form of
  brake was also invented independently by J.A.M.L. Carpentier, and the
  principle has been used in the Raffard brake. A self-compensating
  brake of another kind, by Marcel Deprez, was described with
  Carpentier's in 1880 (_Bulletin de la société d'encouragement_,
  Paris). W.E. Ayrton and J. Perry used a band or rope brake in which
  compensation is effected by the pulley drawing in or letting out a
  part of the band or rope which has been roughened or in which a knot
  has been tied.

  In an effective water-brake invented by W. Froude (see _Proc. Inst. M.
  E._ 1877), two similar castings, A and B, each consisting of a boss
  and circumferential annular channel, are placed face to face on a
  shaft, to which B is keyed, A being free (fig. 4). A ring tube of
  elliptical section is thus formed. Each channel is divided into a
  series of pockets by equally spaced vanes inclined at 45°. When A is
  held still, and B rotated, centrifugal action sets up vortex currents
  in the water in the pockets; thus a continuous circulation is caused
  between B and A, and the consequent changes of momentum give rise to
  oblique reactions. The moments of the components of these actions and
  reactions in a plane to which the axis of rotation is at right angles
  are the two aspects of the torque acting, and therefore the torque
  acting on B through the shaft is measured by the torque required to
  hold A still. Froude constructed a brake to take up 2000 H.P. at 90
  revs. per min. by duplicating this apparatus. This replaced the
  propeller of the ship whose engines were to be tested, and the outer
  casing was held from turning by a suitable arrangement of levers
  carried to weighing apparatus conveniently disposed on the wharf. The
  torque corresponding to 2000 H.P. at 90 revs. per min. is 116,772
  foot-pounds, and a brake 5 ft. in diameter gave this resistance. Thin
  metal sluices were arranged to slide between the wheel and casing, and
  by their means the range of action could be varied from 300 H.P. at
  120 revs. per min. to the maximum.

  [Illustration: FIG. 3.]

  [Illustration: FIG. 4.]

  Professor Osborne Reynolds in 1887 patented a water-brake (see _Proc.
  Inst. C.E._ 99, p. 167), using Froude's turbine to obtain the highly
  resisting spiral vortices, and arranging passages in the casing for
  the entry of water at the hub of the wheel and its exit at the
  circumference. Water enters at E (fig. 5), and finds its way into the
  interior of the wheel, A, driving the air in front of it through the
  air-passages K, K. Then following into the pocketed chambers V1, V2,
  it is caught into the vortex, and finally escapes at the
  circumference, flowing away at F. The air-ways k, k, in the fixed
  vanes establish communication between the cores of the vortices and
  the atmosphere. From {1/5} to 30 H.P. may be measured at 100 revs. per
  min. by a brake-wheel of this kind 18 in. in diameter. For other
  speeds the power varies as the cube of the speed. The casing is held
  from turning by weights hanging on an attached arm. The cocks
  regulating the water are connected to the casing, so that any tilting
  automatically regulates the flow, and therefore the thickness of the
  film in the vortex. In this way the brake may be arranged to maintain
  a constant torque, not withstanding variation of the speed. In G.I.
  Alden's brake (see _Trans. Amer. Soc. Eng._ vol. xi.) the resistance
  is obtained by turning a cast iron disk against the frictional
  resistance of two thin copper plates, which are held in a casing free
  to turn upon the shaft, and are so arranged that the pressure between
  the rubbing surfaces is controlled, and the heat developed by friction
  carried away, by the regulated flow of water through the casing. The
  torque required to hold the casing still against the action of the
  disk measures the torque exerted by the shaft to which the disk is
  keyed.

  [Illustration: Fig. 5.]

  _Transmission Dynamometers._--The essential part of many transmission
  dynamometers is a spring whose deformation indirectly measures the
  magnitude of the force transmitted through it. For many kinds of
  spring the change of form is practically proportional to the force,
  but the relation should always be determined experimentally. General
  A.J. Morin (see _Notice sur divers appareils dynamométriques_, Paris,
  1841), in his classical experiments on traction, arranged his
  apparatus so that the change in form of the spring was continuously
  recorded on a sheet of paper drawn under a style. For longer
  experiments he used a "Compteur" or mechanical integrator, suggested
  by J.V. Poncelet, from which the work done during a given displacement
  could be read off directly. This device consists of a roller of radius
  r, pressed into contact with a disk. The two are carried on a common
  frame, so arranged that a change in form of the spring causes a
  relative displacement of the disk and roller, the point of contact
  moving radially from or towards the centre of the disk. The radial
  distance x is at any instant proportional to the force acting through
  the spring. The angular displacement, [theta], of the disk is made
  proportional to the displacement, s, of the point of application of
  the force by suitable driving gear. If d[phi] is the angular
  displacement of the roller corresponding to displacements, d[theta] of
  the disk, and ds of the point of application of P, a, and C constants,
  then

             xd[theta]   a
    d[phi] = --------- = -- P ds = C·P ds,
                 r       r
                           _
                          /s2
  and therefore [phi] = C |  P ds;
                         _/s1

  that is, the angular displacement of the roller measures the work done
  during the displacement from s1 to s2. The shaft carrying the roller
  is connected to a counter so that [phi] may be observed. The angular
  velocity of the shaft is proportional to the rate of working. Morin's
  dynamometer is shown in fig. 6. The transmitting spring is made up of
  two flat bars linked at their ends. Their centres s1, s2, are held
  respectively by the pieces A, B, which together form a sliding pair.
  The block A carries the disk D, B carries the roller R and counting
  gear. The pulley E is driven from an axle of the carriage. In a
  dynamometer used by F.W. Webb to measure the tractive resistance of
  trains on the London & North-Western railway, a tractive pull or push
  compresses two spiral springs by a definite amount, which is recorded
  to scale by a pencil on a sheet of paper, drawn continuously from a
  storage drum at the rate of 3 in. per mile, by a roller driven from
  one of the carriage axles. Thus the diagram shows the tractive force
  at any instant. A second pencil electrically connected to a clock
  traces a time line on the diagram with a kick at every thirty seconds.
  A third pencil traces an observation line in which a kick can be made
  at will by pressing any one of the electrical pushes placed about the
  car, and a fourth draws a datum line. The spring of the dynamometer
  car used by W. Dean on the Great Western railway is made up of thirty
  flat plates, 7 ft. 6 in. long, 5 in. × 5/8 in. at the centre, spaced
  by distance pieces nibbed into the plates at the centre and by rollers
  at the ends. The draw-bar is connected to the buckle, which is carried
  on rollers, the ends of the spring resting on plates fixed to the
  under-frame. The gear operating the paper roll is driven from the axle
  of an independent wheel which is let down into contact with the rail
  when required. This wheel serves also to measure the distance
  travelled. A Morin disk and roller integrator is connected with the
  apparatus, so that the work done during a journey may be read off.
  Five lines are traced on the diagram.

  [Illustration: FIG. 6.]

  In spring dynamometers designed to measure a transmitted torque, the
  mechanical problem of ascertaining the change of form of the spring is
  complicated by the fact that the spring and the whole apparatus are
  rotating together. In the Ayrton and Perry transmission dynamometer or
  spring coupling of this type, the relative angular displacement is
  proportional to the radius of the circle described by the end of a
  light lever operated by mechanism between the spring-connected parts.
  By a device used by W.E. Dalby (_Proc. Inst. C.E._ 1897-1898, p. 132)
  the change in form of the spring is shown on a fixed indicator, which
  may be placed in any convenient position. Two equal sprocket wheels
  Q1, Q2, are fastened, the one to the spring pulley, the other to the
  shaft. An endless band is placed over them to form two loops, which
  during rotation remain at the same distance apart, unless relative
  angular displacement occurs between Q1 and Q2 (fig. 7) due to a change
  in form of the spring. The change in the distance d is proportional to
  the change in the torque transmitted from the shaft to the pulley. To
  measure this, guide pulleys are placed in the loops guided by a
  geometric slide, the one pulley carrying a scale, and the other an
  index. A recording drum or integrating apparatus may be arranged on
  the pulley frames. A quick variation, or a periodic variation of the
  magnitude of the force or torque transmitted through the springs,
  tends to set up oscillations, and this tendency increases the nearer
  the periodic time of the force variation approaches a periodic time of
  the spring. Such vibrations may be damped out to a considerable extent
  by the use of a dash-pot, or may be practically prevented by using a
  relatively stiff spring.

  [Illustration: FIG. 7.]

  Every part of a machine transmitting force suffers elastic
  deformation, and the force may be measured indirectly by measuring the
  deformation. The relation between the two should in all cases be found
  experimentally. G.A. Hirn (see _Les Pandynamomètres_, Paris, 1876)
  employed this principle to measure the torque transmitted by a shaft.
  Signor Rosio used a telephonic method to effect the same end, and
  mechanical, optical and telephonic devices have been utilized by the
  Rev. F.J. Jervis-Smith. (See _Phil. Mag._ February 1898.)

  H. Frahm,[1] during an important investigation on the torsional
  vibration of propeller shafts, measured the relative angular
  displacement of two flanges on a propeller shaft, selected as far
  apart as possible, by means of an electrical device (_Engineering_,
  6th of February 1903). These measurements were utilized in combination
  with appropriate elastic coefficients of the material to find the
  horse-power transmitted from the engines along the shaft to the
  propeller. In this way the effective horse-power and also the
  mechanical efficiency of a number of large marine engines, each of
  several thousand horse-power, have been determined.

  [Illustration: FIG. 8.]

  When a belt, in which the maximum and minimum tensions are
  respectively P and p lb., drives a pulley, the torque exerted is (P -
  p)r lb. ft., r being the radius of the pulley plus half the thickness
  of the belt. P and p may be measured directly by leading the belt
  round two freely hanging guide pulleys, one in the tight, the other in
  the slack part of the belt, and adjusting loads on them until a stable
  condition of running is obtained. In W. Froude's belt dynamometer (see
  _Proc. Inst. M.E._, 1858) (fig. 8) the guide pulleys G1, G2 are
  carried upon an arm free to turn about the axis O. H is a pulley to
  guide the approaching and receding parts of the belt to and from the
  beam in parallel directions. Neglecting friction, the unbalanced
  torque acting on the beam is 4r{P - p} lb. ft. If a force Q acting at
  R maintains equilibrium, QR/4 = (P - p)r = T. Q is supplied by a
  spring, the extensions of which are recorded on a drum driven
  proportionally to the angular displacement of the driving pulley; thus
  a work diagram is obtained. In the Farcot form the guide pulleys are
  attached to separate weighing levers placed horizontally below the
  apparatus. In a belt dynamometer built for the Franklin Institute from
  the designs of Tatham, the weighing levers are separate and arranged
  horizontally at the top of the apparatus. The weighing beam in the
  Hefner-Alteneck dynamometer is placed transversely to the belt (see
  _Electrotechnischen Zeitschrift_, 1881, 7). The force Q, usually
  measured by a spring, required to maintain the beam in its central
  position is proportional to (P - p). If the angle [theta]1 = [theta]2
  = 120°, Q = (P - p) neglecting friction.

  When a shaft is driven by means of gearing the driving torque is
  measured by the product of the resultant pressure P acting between the
  wheel teeth and the radius of the pitch circle of the wheel fixed to
  the shaft. Fig. 9, which has been reproduced from J. White's _A New
  Century of Inventions_ (Manchester, 1822), illustrates possibly the
  earliest application of this principle to dynamometry. The wheel D,
  keyed to the shaft overcoming the resistance to be measured, is driven
  from wheel N by two bevel wheels L, L, carried in a loose pulley K.
  The two shafts, though in a line, are independent. A torque applied to
  the shaft A can be transmitted to D, neglecting friction, without
  change only if the central pulley K is held from turning; the torque
  required to do this is twice the torque transmitted.

  [Illustration: FIG. 9.]

  The torque acting on the armature of an electric motor is necessarily
  accompanied by an equal and opposite torque acting on the frame. If,
  therefore, the motor is mounted on a cradle free to turn about
  knife-edges, the reacting torque is the only torque tending to turn
  the cradle when it is in a vertical position, and may therefore be
  measured by adjusting weights to hold the cradle in a vertical
  position. The rate at which the motor is transmitting work is then
  T2[pi]n/550 H.P., where n is the revolutions per second of the
  armature.

  See James Dredge, _Electric Illumination_, vol. ii. (London, 1885);
  W.W. Beaumont, "Dynamometers and Friction Brakes," _Proc. Inst. C.E._
  vol. xcv. (London, 1889); E. Brauer, "Über Bremsdynamometer and
  verwandte Kraftmesser," _Zeitschrift des Vereins deutscher Ingenieure_
  (Berlin, 1888); J.J. Flather, _Dynamometers and the Measurement of
  Power_ (New York, 1893).     (W. E. D.)


FOOTNOTE:

  [1] H. Frahm, "Neue Untersuchungen über die dynamischen Vorgänge in
    den Wellenleitungen von Schiffsmaschinen mit besonderer
    Berücksichtigung der Resonanzschwingungen," _Zeitschrift des Vereins
    deutscher Ingenieure_, 31st May 1902.



DYNASTY (Gr. [Greek: dynasteia], sovereignty, the position of a [Greek:
dynastês], lord, ruler, from [Greek: dynasthai], to be able, [Greek:
dynamis], power), a family or line of rulers, a succession of sovereigns
of a country belonging to a single family or tracing their descent to a
common ancestor. The term is particularly used in the history of ancient
Egypt as a convenient means of arranging the chronology.



DYSART, a royal and police burgh and seaport of Fifeshire, Scotland, on
the shore of the Firth of Forth, 2 m. N.E. of Kirkcaldy by the North
British railway. Pop. (1901) 3562. It has a quaint old-fashioned
appearance, many ancient houses in High Street bearing inscriptions and
dates. The public buildings include a town hall, library, cottage
hospital, mechanics' institute and memorial hall. Scarcely anything is
left of the old chapel dedicated to St Dennis, which for a time was used
as a smithy; and of the chapel of St Serf, the patron saint of the
burgh, only the tower remains. The chief industries are the manufacture
of bed and table linen, towelling and woollen cloth, shipbuilding and
flax-spinning. There is a steady export of coal, and the harbour is
provided with a wet dock and patent slip. In smuggling days the "canty
carles" of Dysart were professed "free traders." In the 15th and 16th
centuries the town was a leading seat of the salt industry ("salt to
Dysart" was the equivalent of "coals to Newcastle"), but the salt-pans
have been abandoned for a considerable period. Nail-making, once famous,
is another extinct industry. During the time of the alliance between
Scotland and Holland, which was closer in Fifeshire than in other
counties, Dysart became known as Little Holland. To the west of the town
is Dysart House, the residence of the earl of Rosslyn. With Burntisland
and Kinghorn Dysart forms one of the Kirkcaldy district group of
parliamentary burghs. The town is mentioned as early as 874 in connexion
with a Danish invasion. Its name is said to be a corruption of the Latin
_desertum_, "a desert," which was applied to a cave on the seashore
occupied by St Serf. In the cave the saint held his famous colloquy with
the devil, in which Satan was worsted and contemptuously dismissed. From
James V. the town received the rights of a royal burgh. In 1559 it was
the headquarters of the Lords of the Congregation, and in 1607 the scene
of the meetings of the synod of Fife known as the Three Synods of
Dysart. Ravensheugh Castle, on the shore to the west of the town, is the
Ravenscraig of Sir Walter Scott's ballad of "Rosabelle."

William Murray, a native of the place, was made earl of Dysart in 1643,
and his eldest child and heir, a daughter, Elizabeth, obtained in 1670 a
regrant of the title, which passed to the descendants of her first
marriage with Sir Lionel Tollemache, Bart., of Helmingham; she married
secondly the 1st duke of Lauderdale, but had no children by him, and
died in 1698. This countess of Dysart (afterwards duchess of Lauderdale)
was a famous beauty of the period, and notorious both for her amours and
for her political influence. She was said to have been the mistress of
Oliver Cromwell, and also of Lauderdale before her first husband's
death, and was a leader at the court of Charles II. Wycherley is
supposed to have aimed at her in his Widow Blackacre in the _Plain
Dealer_. Her son, Lionel Tollemache (d. 1727), transmitted the earldom
to his grandson Lionel (d. 1770), whose sons Lionel (d. 1799) and
Wilbraham (d. 1821) succeeded; they died without issue, and their sister
Louisa (d. 1840), who married John Manners, an illegitimate son of the
second son of the 2nd duke of Rutland, became countess in her own right,
being succeeded by her grandson (d. 1878), and his grandson, the 8th
earl.

The earldom of Dysart must not be confounded with that of Desart
(Irish), created (barony 1733) in 1793, and held in the Cuffe family,
who were originally of Creech St Michael, Somerset, the Irish branch
dating from Queen Elizabeth's time.



DYSENTERY (from the Gr. prefix [Greek: dys]-, in the sense of "bad," and
[Greek: enteron], the intestine), also called "bloody flux," an
infectious disease with a local lesion in the form of inflammation and
ulceration of the lower portion of the bowels. Although at one time a
common disease in Great Britain, dysentery is now very rarely met with
there, and is for the most part confined to warm countries, where it is
the cause of a large amount of mortality. (For the pathology see
DIGESTIVE ORGANS.)

Recently considerable advance has been made in our knowledge of
dysentery, and it appears that there are two distinct types of the
disease: (1) amoebic dysentery, which is due to the presence of the
amoeba histolytica (of Schaudinn) in the intestine; (2) bacillary
dysentery, which has as causative agent two separate bacteria, (a) that
discovered by Shiga in Japan, (b) that discovered by Flexner in the
Philippine Islands. With regard to the bacillary type, at first both
organisms were considered to be identical, and the name _bacillus
dysenteriae_ was given to them; but later it was shown that these
bacilli are different, both in regard to their cultural characteristics
and also in that one (Shiga) gives out a soluble toxin, whilst the
other has so far resisted all efforts to discover it. Further, the
serum of a patient affected with one of the types has a marked
agglutinative power on the variety with which he is infected and not on
the other.

Clinically, dysentery manifests itself with varying degrees of
intensity, and it is often impossible without microscopical examination
to determine between the amoebic and bacillary forms. In well-marked
cases the following are the chief symptoms. The attack is commonly
preceded by certain premonitory indications in the form of general
illness, loss of appetite, and some amount of diarrhoea, which gradually
increases in severity, and is accompanied with griping pains in the
abdomen (tormina). The discharges from the bowels succeed each other
with great frequency, and the painful feeling of pressure downwards
(tenesmus) becomes so intense that the patient is constantly desiring to
defecate. The matters passed from the bowels, which at first resemble
those of ordinary diarrhoea, soon change their character, becoming
scanty, mucous or slimy, and subsequently mixed with, or consisting
wholly of, blood, along with shreds of exudation thrown off from the
mucous membrane of the intestine. The evacuations possess a peculiarly
offensive odour characteristic of the disease. Although the
constitutional disturbance is at first comparatively slight, it
increases with the advance of the disease, and febrile symptoms come on
attended with urgent thirst and scanty and painful flow of urine. Along
with this the nervous depression is very marked, and the state of
prostration to which the patient is reduced can scarcely be exceeded.
Should no improvement occur death may take place in from one to three
weeks, either from repeated losses of blood, or from gradual exhaustion
consequent on the continuance of the symptoms, in which case the
discharges from the bowels become more offensive and are passed
involuntarily.

When, on the other hand, the disease is checked, the signs of
improvement are shown in the cessation of the pain, in the evacuations
being less frequent and more natural, and in relief from the state of
extreme depression. Convalescence is, however, generally slow, and
recovery may be imperfect--the disease continuing in a chronic form,
which may exist for a variable length of time, giving rise to much
suffering, and not unfrequently leading to an ultimately fatal result.

The dysentery poison appears to exert its effects upon the glandular
structures of the large intestine, particularly in its lower part. In
the milder forms of the disease there is simply a congested or inflamed
condition of the mucous membrane, with perhaps some inflammatory
exudation on its surface, which is passed off by the discharges from the
bowels. But in the more severe forms ulceration of the mucous membrane
takes place. Commencing in and around the solitary glands of the large
intestine in the form of exudations, these ulcers, small at first,
enlarge and run into each other, till a large portion of the bowel may
be implicated in the ulcerative process. Should the disease be arrested
these ulcers may heal entirely, but occasionally they remain, causing
more or less disorganization of the coats of the intestines, as is often
found in chronic dysentery. Sometimes, though rarely, the ulcers
perforate the intestines, causing rapidly fatal inflammation of the
peritoneum, or they may erode a blood vessel and produce violent
haemorrhage. Even where they undergo healing they may cause such a
stricture of the calibre of the intestinal canal as to give rise to the
symptoms of obstruction which ultimately prove fatal. One of the
severest complications of the disease is abscess of the liver, usually
said to be solitary, and known as tropical abscess of the liver, but
probably is more frequently multiple than is usually thought.

_Treatment._--Where the disease is endemic or is prevailing
epidemically, it is of great importance to use all preventive measures,
and for this purpose the avoidance of all causes likely to precipitate
an attack is to be enjoined. Exposure to cold after heat, the use of
unripe fruit, and intemperance in eating and drinking should be
forbidden; and the utmost care taken as to the quality of the food and
drinking water. In houses or hospitals where cases of the disease are
under treatment, disinfectants should be freely employed, and the
evacuations of the patients removed as speedily as possible, having
previously been sterilized in much the same manner as is employed in
typhoid fever. In the milder varieties of this complaint, such as those
occurring sporadically, and where the symptoms are probably due to
matters in the bowels setting up the dysenteric irritation, the
employment of diaphoretic medicines is to be recommended, and the
administration of such a laxative as castor oil, to which a small
quantity of laudanum has been added, will often, by removing the source
of the mischief, arrest the attack; but a method of treatment more to be
recommended is the use of salines in large doses, such as one drachm of
sodium sulphate from four to eight times a day. This treatment may with
advantage be combined with the internal administration of ipecacuanha,
which still retains its reputation in this disease. Latterly, free
irrigation of the bowel with astringents, such as silver nitrate,
tannalbin, &c., has been attended with success in those cases which have
been able to tolerate the injections. In many instances they cannot be
used owing to the extreme degree of irritability of the bowel. The
operation of appendicostomy, or bringing the appendix to the surface and
using it as the site for the introduction of the irrigating fluid, has
been attended with considerable success.

In those cases due to Shiga's bacillus the ideal treatment has been put
at our disposal by the preparation of a specific antitoxin; this has
been given a trial in several grave epidemics of late, and may be said
to be the most satisfactory treatment and offer the greatest hope of
recovery. It is also of great use as a prophylactic.

The preparations of morphia are of great value in the symptomatic
treatment of the disease. They may be applied externally as
fomentations, for the relief of tormina; by rectal injection for the
relief of the tenesmus and irritability of the bowel; hypodermically in
advanced cases, for the relief of the general distress. In amoebic
dysentery, warm injections of quinine _per rectum_ have proved very
efficacious, are usually well tolerated, and are not attended with any
ill effects. The diet should be restricted, consisting chiefly of soups
and farinaceous foods; more especially is this of importance in the
chronic form. For the thirst ice may be given by the mouth. Even in the
chronic forms, confinement to bed and restriction of diet are the most
important elements of the treatment. Removal from the hot climate and
unhygienic surroundings must naturally be attended to.

  BIBLIOGRAPHY.--Allbutt and Rolleston, _System of Medicine_, vol. ii.
  part ii. (1907), "Dysentery," Drs Andrew Davidson and Simon Flexner;
  Davidson, _Hygiene and Diseases of Warm Climates_ (Edinburgh, 1903);
  Fearnside in _Ind. Med. Gaz._ (July 1905); Ford in _Journal of
  Tropical Medicine_ (July 15, 1904); Korentchewsky in _Bulletin de
  l'Institut Pasteur_ (February 1905); Shiga: Osier and M'Crae's _System
  of Medicine_, vol. ii. p. 781 (1907); Skschivan and Stefansky in
  _Berliner klinische Wochenschrift_ (February 11, 1907); Vaillard and
  Dopter, on the treatment by antidysenteric serum, _Annales de
  l'Institut Pasteur_, No. 5, p. 326 (1906); J.A. Pottinger,
  "Appendicostomy in Chronic Dysentery," _Lancet_ (December 28, 1907);
  Robert Doerr, _Das Dysenterietoxin_ (Gustav Fischer, Jena, 1907); F.M.
  Sandwith, "Hunterian Lecture on the Treatment of Dysentery," _Lancet_
  (December 7, 1907).



DYSPEPSIA (from the Gr. prefix [Greek: dys-], hard, ill, and [Greek:
peptein], to digest), or indigestion, a term vaguely given to a group of
pathological symptoms. There are comparatively few diseases of any
moment where some of the phenomena of dyspepsia are not present as
associated symptoms, and not infrequently these exist to such a degree
as to mask the real disease, of which they are only complications. This
is especially the case in many organic diseases of the alimentary canal,
in which the symptoms of dyspepsia are often the most prominent. In its
restricted meaning, however (and it is to this that the present article
applies), the term is used to describe a functional derangement of the
natural process of digestion, apart from any structural change in the
organs concerned in the act.

The causes of this trouble may be divided into (a) those which concern
the food, and (b) those which concern the organism. Among the causes
connected with the food are not only the indulgence in indigestible
articles of diet, but the too common practice of eating too much of
what may be otherwise quite wholesome and digestible; and irregular, too
frequent or too infrequent meals. The quantity of food required by
different individuals varies between wide limits, but also the quantity
required by the same individual varies considerably according to
circumstances, more food being needed in cold than in warm weather, and
more in an active open-air occupation than in a sedentary one. The
thorough mastication of the food is a very important precursor of
digestion,[1] and this only too often fails, either owing to haste over
meals or because of painful or deficient teeth. Again, the quality of
the food is of importance, some kinds of flesh being harder and more
difficult of mastication than others. This is especially the case with
meat that has been smoked or salted, and with that cooked too soon after
the death of the animal. Drinks are a common source of dyspepsia. Beer
when new and its fermentation not completed is especially bad. Vinegar
and acid wines, if taken in large quantities, tend to produce gastric
catarrh, and tea is a very fruitful source of this trouble. Even too
much water at meal-times may cause indigestion, since the food in the
mouth is apt to be softened by the water instead of saliva, and also the
gastric juice becomes unduly diluted, rendering the digestion in the
stomach too slow and prolonged. Carious teeth and oral sepsis, from
whatsoever cause, lead to the same trouble.

Of the causes which concern the organism, nervous influences come first.
Bad news may take away all power of digestion and even provoke vomiting,
and any worry or mental trouble tends to bring on this condition.
General weakness and atony of the body affects the stomach in like
degree, and, if the muscles of the abdominal wall be much wasted, they
become too weak to support the abdominal viscera in place. Hence results
a general tendency for these organs to fall, giving rise to a condition
of visceroptosis, of which an obstinate dyspepsia is a very marked
feature. Adhesions of the intestines from old inflammatory troubles,
floating kidney and bad circulation may each be a cause of painful
digestion. Again, a dyspepsia that will not yield to treatment is often
one of the symptoms of renal disease, or, in young people of fifteen to
twenty years of age, it may be the earliest sign of a gouty diathesis,
or even of a more serious condition still--incipient phthisis. Chronic
dyspepsia, by weakening the organism, renders it more liable to fall a
prey to the attacks of the tubercle bacillus, but, on the other hand,
the tuberculous lesion in the lung is often accompanied by a most
intractable form of dyspepsia. From this it is clear that any condition
which lessens the general well-being of the organism as a whole, apart
from its producing any permanent morbid condition in the stomach, may
yet interfere with the normal digestive processes and so give rise to
dyspepsia.

The symptoms of dyspepsia, even when due to a like cause, are so
numerous and diversified in different individuals that probably no
description could exactly represent them as they occur in any given
case. All that can be here attempted is to mention some of the more
prominent morbid phenomena usually present in greater or less degree.

Very briefly, a furred tongue, foul breath, disturbance of appetite,
nausea and vomiting, oppression in the chest, pain, flatulence and
distension, acidity, pyrosis and constipation or diarrhoea are a few of
the commonest symptoms.

When the attack is dependent on some error in diet, and the dyspepsia
consequently more of an acute character, there is often pain followed
with sickness and vomiting of the offensive matters, after which the
patient soon regains his former healthy state. What are commonly known
as "bilious attacks" are frequently of this character. In the more
chronic cases of dyspepsia the symptoms are somewhat different. A
sensation of discomfort comes on shortly after a meal, and is more of
the nature of weight and distension in the stomach than of actual pain,
although this too may be present. These feelings may come on after each
meal, or only after certain meals, and they may arise irrespective of
the kind of food taken, or only after certain articles of diet. As in
most of such cases the food is long retained in the stomach, it is apt
to undergo fermentive changes, one of the results of which is the
accumulation of gases which cause flatulence and eructations of an acid
or foul character. Occasionally quantities of hot, sour, tasteless or
bitter fluid--pyrosis--or mouthfuls of half-digested food, regurgitate
from the stomach. Temporary relief may be obtained when another meal is
taken, but soon the uncomfortable sensations return as before. The
appetite may be craving or deficient, or desirous of abnormal kinds of
food. The tongue registers the gastric condition with great delicacy;--a
pasty white fur on the tongue is considered a sign of weakness or atony
of the digestive tract; a clean pointed tongue with large papillae, and
rather red at the edges and tip, is a sign of gastric irritation; and a
pale flabby tongue suggests the need of stimulating treatment.
Constipation is more common in the chronic forms of dyspepsia, diarrhoea
in the acute.

Numerous disagreeable and painful sensations in other parts are
experienced, and are indeed often more distressing than the merely
gastric symptoms. Pains in the chest, shortness of breathing,
palpitation, headache, giddiness, affections of vision, coldness of the
extremities, and general languor are common accompaniments of dyspepsia;
while the nervous phenomena are specially troublesome in the form of
sleeplessness, irritability, despondency and hypochondriasis.

As regards _treatment_ only a few general observations can be made. The
careful arrangement of the diet is a matter of first importance.
Quantity must be regulated by the digestive capabilities of the
individual, his age, and the demands made upon his strength by work.
There is little doubt that the danger is in most instances on the side
of excess, and the rule which enjoins the cessation from eating before
the appetite is satisfied is a safe one for dyspeptics. Due time, too,
must be given for the digestion of a meal, and from four to six hours
are in general required for this purpose. Long fasts, however, are
nearly as hurtful as too frequent meals. Of no less importance is the
kind of food taken, and on this point those who suffer from indigestion
must ever exercise the greatest care. It must be borne in mind that
idiosyncrasy often plays an important part in digestion, some persons
being unable to partake without injury of substances which are generally
regarded as wholesome and digestible. In most cases it is found very
helpful to separate the protein from the farinaceous food, and the more
severe the dyspepsia the more thoroughly should this be done, only
relaxing as the dyspepsia yields. No fluid should be drunk at
meal-times, but from one to two tumblers of hot water should be drunk
from an hour to an hour and a half before food. This washes any remnant
of the last meal from the stomach, and also supplies material for the
free secretion of saliva and gastric juice, thus promoting and
accelerating digestion. The only exception to this is in the case of a
dilated stomach, when it is wholly contra-indicated. With regard to
mastication, Sir Andrew Clark's rule is a very good one, and is more
easily followed than the ideal theory laid down by Horace Fletcher,
according to whom any food is digestible if properly treated while still
in the mouth. Clark's rule is that as the mouth normally contains
thirty-two teeth, thirty-two bites should be given before the food is
swallowed. This, of course, is a practical doctor's concession to human
weakness. Mr Fletcher would train every one to "chew" till the contents
of the mouth were swallowed by reflex action without deliberate act; and
he applies this theory of mastication and salivation also to drinks
(except water). Again, a lack of warmth being a source of dyspepsia,
this should be attended to, the back of the neck, the front of the
abdomen and the feet being the parts that require special attention. The
feet should be raised on a stool, the ankles protected with warm
stockings and a woollen "cummerbund" wound two or three times round the
body. Experience has shown that in this complaint no particular kind of
food or avoidance of food is absolutely to be relied on, but that in
general the best diet is one of a mixed animal and vegetable kind,
simply but well cooked. The partaking of many dishes, of highly-seasoned
or salted meats, raw vegetables, newly-baked bread, pastry and
confectionery are all well-known common causes of dyspepsia, and should
be avoided. When even the simple diet usually taken is found to
disagree, it may be necessary to change it temporarily for a still
lighter form, such as a milk diet, and that even in very moderate
quantity.

The employment of alcoholic stimulants to assist digestion is largely
resorted to, both with and without medical advice. While it seems
probable that in certain cases of atonic dyspepsia, particularly in the
feeble and aged, the moderate administration of alcohol has the effect
of stimulating the secretion of gastric juice, and is an important
adjuvant to other remedies, the advantages of its habitual use as an aid
to digestion by the young and otherwise healthy, is more than
questionable, and it will generally be found that among them, those are
least troubled with indigestion who abstain from it. Rest should be
taken both before and after food, and general hygienic measures are
highly important, since whatever improves the state of the health will
have a favourable influence on digestion. Hence regular exercise in the
open air, early rising and the cold bath are to be strongly recommended.

The medicinal treatment of dyspepsia can only be undertaken by a
physician, but the following is a very brief résumé of the drugs he
depends on to-day. Bicarbonate of soda with some bitter, as quassia,
gentian or columba, is much in vogue as a direct gastric stimulant. In
irritable dyspepsia some form of bismuth in solution or powder; and, to
assist digestion through the nervous system, nux vomica and strychnine
can be relied on. To give directly digestive material, hydrochloric
acid, pepsin and rennet are prescribed in many forms, but where there is
much vomiting ingluvin is more efficacious than pepsin. When farinaceous
food is badly borne, diastase is helpful, given either before or with
the meal. To prevent fermentation, phenol, creasote and sulpho-carbolate
of soda are all extremely useful in skilled hands; and for intestinal
decomposition and flatulent distension, bismuth salicylate with salol or
ß-naphthol is much used. Cyllin, and charcoal in many forms, may be
taken both for gastric and intestinal flatulence. But all these drugs,
of proved value though they are, must be modified and combined to suit
the special idiosyncrasy of the patient, and are therefore often worse
than useless in inexperienced hands. The condition of the bowels must
always have due attention.

  See also DIGESTIVE ORGANS; NUTRITION and DIETETICS.


FOOTNOTE:

  [1] This aspect of the matter--"buccal digestion"--has been specially
    emphasized in recent years by Horace Fletcher of the United States,
    whose experience of the results of systematic "chewing," confirmed by
    Sir M. Foster, Prof. Chittenden and others, has almost revolutionized
    the science of dietetics.



DYSTELEOLOGY, a modern word invented by Haeckel (_Evolution of Man_) for
the doctrine of purposelessness, as opposed to the philosophical
doctrine of design (Teleology).



DZUNGARIA, DSONGARIA, or JUNGARIA, a former Mongolian kingdom of Central
Asia, raised to its highest pitch by Kaldan or Bushtu Khan in the latter
half of the 17th century, but completely destroyed by Chinese invasion
about 1757-1759. It has played an important part in the history of
Mongolia and the great migrations of Mongolian stems westward. Now its
territory belongs partly to the Chinese empire (east Turkestan and
north-western Mongolia) and partly to Russian Turkestan (provinces of
Semiryechensk and Semipalatinsk). It derived its name from the Dsongars,
or Songars, who were so called because they formed the left wing
(_dson_, left; _gar_, hand) of the Mongolian army. Its widest limit
included Kashgar, Yarkand, Khotan, the whole region of the T'ien Shan,
or Tian-shan, Mountains, and in short the greater proportion of that
part of Central Asia which extends from 35° to 50° N. and from 72° to
97° E. The name, however, is more properly applied only to the present
Chinese province of T'ien Shan-pei-lu and the country watered by the
Ili. As a political or geographical term it has practically disappeared
from the map; but the range of mountains stretching north-east along the
southern frontier of the Land of the Seven Streams, as the district to
the south-east of the Balkhash Lake is called, preserves the name of
Dzungarian Range.



E The fifth symbol in the English alphabet occupies also the same
position in Phoenician and in the other alphabets descended from
Phoenician. As the Semitic alphabet did not represent vowels, E was
originally an aspirate. Its earliest form, while writing is still from
right to left, is [symbol], the upright being continued some distance
below the lowest of the cross-strokes. In some of the Greek alphabets it
appears as [symbol] with the upright prolonged at both top and bottom,
but it soon took the form with which we are familiar, though in the
earlier examples of this form the cross-strokes are not horizontal but
drop at an angle, [symbol]. In Corinth and places under its early
influence like Megara, or colonized from it like Corcyra, the symbol for
_e_ takes the form [symbol] or [symbol], while at Sicyon in the 6th and
5th centuries B.C. it is represented by [symbol]. In early Latin it was
sometimes represented by two perpendicular strokes of equal length,
[symbol].

In the earliest Greek inscriptions and always in Latin the symbol E
represented both the short and the long _e_-sound. In Greek also it was
often used for the close long sound which arose either by contraction of
two short _e_-sounds or by the loss of a consonant, after a short
_e_-sound, as in [Greek: phileite], "you love," for [Greek: phileete],
and [Greek: phaeinos], "bright," out of an earlier [Greek: phaesnos].
The Ionian Greeks of Asia Minor, who had altogether lost the aspirate,
were the first to use the symbol H for the long _e_-sound, and in
official documents at Athens down to 403 B.C., when the Greek alphabet
as still known was adopted by the state, E represented [epsilon], [eta]
and the sound arising by contraction or consonant loss as mentioned
above which henceforth was written with two symbols, [Greek: ei], and
being really a single sound is known as the "spurious diphthong." There
were some minor distinctions in usage of the symbols E and H which need
not here be given in detail. The ancient Greek name was [Greek: ei], not
_Epsilon_ as popularly supposed; the names of the Greek letters are
given from Kallias, an earlier contemporary of Euripides, in Athenaeus
x. p. 453 d.

In Greek the short _e_-sound to which E was ultimately limited was a
close sound inclining more towards _i_ than _a_; hence the
representation of the contraction of [Greek: ee] by [Greek: ei]. Its
value in Latin was exactly the opposite, the Latin short _e_ being open,
and the long close. In English there has been a gradual narrowing of the
long vowels, _a_ becoming approximately _ei_ and _e_ becoming _i_
(Sweet, _History of English Sounds_, §§ 781, 817 ff. 2nd ed.). In
languages where the diphthong _ai_ has become a monophthong, the
resulting sound is some variety of long _e_. Often the gradual
assimilation can be traced through the intermediate stage of _ae_ to
_e_, as in the Old Latin _aidilis_, which in classical Latin is
_aedilis_, and in medieval MSS. _edilis_.

The variety of spelling in English for the long and short _e_-sounds is
conveniently illustrated in Miss Soames's _Introduction to the Study of
Phonetics_, pp. 16 and 20.     (P. Gi.)



EA (written by means of two signs signifying "house" and "water"), in
the Babylonian religion, originally the patron deity of Eridu, situated
in ancient times at the head of the Persian Gulf, but now, by reason of
the constant accumulation of soil in the Euphrates valley, at some
distance from the gulf. Eridu, meaning "the good city," was one of the
oldest settlements in the Euphrates valley, and is now represented by
the mounds known as Abu Shahrein. In the absence of excavations on that
site, we are dependent for our knowledge of Ea on material found
elsewhere. This is, however, sufficient to enable us to state definitely
that Ea was a water-deity, and there is every reason to believe that the
Persian Gulf was the body of water more particularly sacred to him.
Whether Ea (or A-e as some scholars prefer) represents the real
pronunciation of his name we do not know. All attempts to connect Ea
with Yah and Yahweh are idle conjectures without any substantial basis.
He is figured as a man covered with the body of a fish, and this
representation, as likewise the name of his temple E-apsu, "house of
the watery deep," points decidedly to his character as a god of the
waters (see OANNES). Of his cult at Eridu, which reverts to the oldest
period of Babylonian history, nothing definite is known beyond the fact
that the name of his temple was E-saggila, "the lofty house"--pointing
to a staged tower as in the case of the temple of Bel (q.v.) at Nippur,
known as E-Kur, i.e. "mountain house"--and that incantations, involving
ceremonial rites, in which water as a sacred element played a prominent
part, formed a feature of his worship. Whether Eridu at one time also
played an important political rôle is not certain, though not
improbable. At all events, the prominence of the Ea cult led, as in the
case of Nippur, to the survival of Eridu as a sacred city, long after it
had ceased to have any significance as a political centre. Myths in
which Ea figures prominently have been found in Assur-bani-pal's
library, indicating that Ea was regarded as the protector and teacher of
mankind. He is essentially a god of civilization, and it was natural
that he was also looked upon as the creator of man, and of the world in
general. Traces of this view appear in the Marduk epic celebrating the
achievements of this god, and the close connexion between the Ea cult at
Eridu and that of Marduk also follows from two considerations: (1) that
the name of Marduk's sanctuary at Babylon bears the same name,
E-saggila, as that of Ea in Eridu, and (2) that Marduk is generally
termed the son of Ea, who derives his powers from the voluntary
abdication of the father in favour of his son. Accordingly, the
incantations originally composed for the Ea cult were re-edited by the
priests of Babylon and adapted to the worship of Marduk, and, similarly,
the hymns to Marduk betray traces of the transfer of attributes to
Marduk which originally belonged to Ea.

It is, however, more particularly as the third figure in the triad, the
two other members of which were Anu (q.v.) and Bel (q.v.), that Ea
acquires his permanent place in the pantheon. To him was assigned the
control of the watery element, and in this capacity he becomes the _shar
apsi_, i.e. king of the Apsu or "the deep." The Apsu was figured as an
ocean encircling the earth, and since the gathering place of the dead,
known as Aralu, was situated near the confines of the Apsu, he was also
designated as En-Ki, i.e. "lord of that which is below," in contrast to
Anu, who was the lord of the "above" or the heavens. The cult of Ea
extended throughout Babylonia and Assyria. We find temples and shrines
erected in his honour, e.g. at Nippur, Girsu, Ur, Babylon, Sippar and
Nineveh, and the numerous epithets given to him, as well as the various
forms under which the god appears, alike bear witness to the popularity
which he enjoyed from the earliest to the latest period of
Babylonian-Assyrian history. The consort of Ea, known as Damkina, "lady
of that which is below," or Nin-Ki, having the same meaning, or
Damgal-nunna, "great lady of the waters," represents a pale reflection
of Ea and plays a part merely in association with her lord.     (M. Ja.)



EABANI, the name of the friend of Gilgamesh, the hero in the Babylonian
epic (see GILGAMESH, EPIC OF). Eabani, whose name signifies "Ea
creates," pointing to the tradition which made the god Ea (q.v.) the
creator of mankind, is represented in the epic as the type of the
primeval man. He is a wild man who lives with the animals of the field
until lured away from his surroundings by the charms of a woman. Created
to become a rival to Gilgamesh, he strikes up a friendship with the
hero, and together they proceed to a cedar forest guarded by Khumbaba,
whom they kill. The goddess Irnina (a form of Ishtar, q.v.) in revenge
kills Eabani, and the balance of the epic is taken up with Gilgamesh's
lament for his friend, his wanderings in quest of a remote ancestor,
Ut-Napishtim, from whom he hopes to learn how he may escape the fate of
Eabani, and his finally learning from his friend of the sad fate in
store for all mortals except the favourites of the god, like
Ut-Napishtim, to whom immortal life is vouchsafed as a special boon.
     (M. Ja.)



EACHARD, JOHN (1636?-1697), English divine, was born in Suffolk, and was
educated at Catharine Hall, Cambridge, of which he became master in 1675
in succession to John Lightfoot. He was created D.D. in 1676 by royal
mandate, and was twice (in 1679 and 1695) vice-chancellor of the
university. He died on the 7th of July 1697. In 1670 he had published
anonymously a humorous satire entitled _The Ground and Occasions of the
Contempt of the Clergy enquired into in a letter to R. L._, which
excited much attention and provoked several replies, one of them being
from John Owen. These were met by _Some Observations, &c., in a second
letter to R. L._ (1671), written in the same bantering tone as the
original work. Eachard attributed the contempt into which the clergy had
fallen to their imperfect education, their insufficient incomes, and the
want of a true vocation. His descriptions, which were somewhat
exaggerated, were largely used by Macaulay in his _History of England_.
He gave amusing illustrations of the absurdity and poverty of the
current pulpit oratory of his day, some of them being taken from the
sermons of his own father. He attacked the philosophy of Hobbes in his
_Mr Hobb's State of Nature considered; in a dialogue between Philautus
and Timothy_ (1672), and in his _Some Opinions of Mr Hobbs considered in
a second dialogue_ (1673). These were written in their author's chosen
vein of light satire, and Dryden praised them as highly effective within
their own range. Eachard's own sermons, however, were not superior to
those he satirized. Swift (_Works_, xii. 279) alludes to him as a signal
instance of a successful humorist who entirely failed as a serious
writer.

  A collected edition of his works in three volumes, with a notice of
  his life, was published in 1774. The _Contempt of the Clergy_ was
  reprinted in E. Arber's _English Garner_. _A Free Enquiry into the
  Causes of the very great Esteem that the Nonconforming Preachers are
  generally in with their Followers_ (1673) has been attributed to
  Eachard on insufficient grounds.



EADBALD (d. 640), king of Kent, succeeded to the throne on the death of
his father Æthelberht in 616. He had not been influenced by the teaching
of the Christian missionaries, and his first step on his accession was
to marry his father's widow. After his subsequent conversion by
Laurentius, archbishop of Canterbury, he recalled the bishops Mellitus
and Justus, and built a church dedicated to the Virgin at Canterbury. He
arranged a marriage between his sister Æthelberg and Edwin of
Northumbria, on whose defeat and death in 633 he received his sister and
Paulinus, and offered the latter the bishopric of Rochester. Eadbald
married Emma, a Frankish princess, and died on the 20th of January 640.

  See Bede, _Historia ecclesiastica_ (ed. C. Plummer, Oxford, 1896);
  _Saxon Chronicle_ (ed. J. Earle and C. Plummer, Oxford, 1899).



EADIE, JOHN (1810-1876), Scottish theologian and biblical critic, was
born at Alva, in Stirlingshire, on the 9th of May 1810. Having taken the
arts curriculum at Glasgow University, he studied for the ministry at
the Divinity Hall of the Secession Church, a dissenting body which, on
its union a few years later with the Relief Church, adopted the title
United Presbyterian. In 1835 he became minister of the Cambridge Street
Secession church in Glasgow, and for many years he was generally
regarded as the leading representative of his denomination in Glasgow.
As a preacher, though he was not eloquent, he was distinguished by good
sense, earnestness and breadth of sympathy. In 1863 he removed with a
portion of his congregation to a new church at Lansdowne Crescent. In
1843 Eadie was appointed professor of biblical literature and
hermeneutics in the Divinity Hall of the United Presbyterian body. He
held this appointment along with his ministerial charge till the close
of his life. Though not a profound scholar, he was surpassed by few
biblical commentators of his day in range of learning, and in soundness
of judgment. In the professor's chair, as in the pulpit, his strength
lay in the tact with which he selected the soundest results of biblical
criticism, whether his own or that of others, and presented them in a
clear and connected form, with a constant view to their practical
bearing. He received the degree of LL.D. from Glasgow in 1844, and that
of D.D. from St Andrews in 1850.

His publications were connected with biblical criticism and
interpretation, some of them being for popular use and others more
strictly scientific. To the former class belong the _Biblical
Cyclopaedia_, his edition of _Cruden's Concordance_, his _Early Oriental
History_, and his discourses on the _Divine Love_ and on _Paul the
Preacher_; to the latter his commentaries on the Greek text of St Paul's
epistles to the Ephesians, Colossians, Philippians and Galatians,
published at intervals in four volumes. His last work was the _History
of the English Bible_ (2 vols., 1876). He rendered good service as one
of the revisers of the authorized version. He died at Glasgow on the 3rd
of June 1876. His valuable library was bought and presented to the
United Presbyterian College.



EADMER, or EDMER (c. 1060-c. 1124), English historian and ecclesiastic,
was probably, as his name suggests, of English, and not of Norman
parentage. He became a monk in the Benedictine monastery of Christ
Church, Canterbury, where he made the acquaintance of Anselm, at that
time visiting England as abbot of Bec. The intimacy was renewed when
Anselm became archbishop of Canterbury in 1093; thenceforward Eadmer was
not only his disciple and follower, but his friend and director, being
formally appointed to this position by Pope Urban II. In 1120 he was
nominated to the archbishopric of St Andrews, but as the Scots would not
recognize the authority of the see of Canterbury he was never
consecrated, and soon afterwards he resigned his claim to the
archbishopric. His death is generally assigned to the year 1124.

Eadmer left a large number of writings, the most important of which is
his _Historiae novorum_, a work which deals mainly with the history of
England between 1066 and 1122. Although concerned principally with
ecclesiastical affairs scholars agree in regarding the _Historiae_ as
one of the ablest and most valuable writings of its kind. It was first
edited by John Selden in 1623 and, with Eadmer's _Vita Anselmi_, has
been edited by Martin Rule for the "Rolls Series" (London, 1884). The
_Vita Anselmi_, first printed at Antwerp in 1551, is probably the best
life of the saint. Less noteworthy are Eadmer's lives of St Dunstan, St
Bregwin, archbishop of Canterbury, and St Oswald, archbishop of York;
these are all printed in Henry Wharton's _Anglia Sacra_, part ii.
(1691), where a list of Eadmer's writings will be found. The manuscripts
of most of Eadmer's works are preserved in the library of Corpus Christi
College, Cambridge.

  See M. Rule, _On Eadmer's Elaboration of the first four Books of
  "Historiae novorum"_ (1886); and Père Ragey, _Eadmer_ (Paris, 1892).



EADS, JAMES BUCHANAN (1820-1887), American engineer, was born at
Lawrenceburg, Indiana, on the 23rd of May 1820. His first engineering
work of any importance was in raising sunken steamers. In 1845 he
established glass works in St Louis. During the Civil War he constructed
ironclad steamers and mortar boats for the Federal government. His next
important engineering achievement was the construction of the great
steel arch bridge across the Mississippi at St Louis (see BRIDGE, fig.
29), upon which he was engaged from 1867 till 1874. The work, however,
upon which his reputation principally rests was his deepening and fixing
the channel at the mouths of the Mississippi by means of jetties,
whereby the narrowed stream was made to scour out its own channel and
carry the sediment out to sea. Shortly before his death he projected a
scheme for a ship railway across the Isthmus of Tehuantepec, in lieu of
an isthmian canal. He died at Nassau, in the Bahamas, on the 8th of
March 1887.



EAGLE (Fr. _aigle_, from the Lat. _aquila_), the name generally given to
the larger diurnal birds of prey which are not vultures; but the limits
of the subfamily _Aquilinae_ have been very variously assigned by
different writers on systematic ornithology, and there are eagles
smaller than certain buzzards. By some authorities the _Laemmergeier_ of
the Alps, and other high mountains of Europe, North Africa and Asia, is
accounted an eagle, but by others the genus _Gypaetus_ is placed with
the _Vulturidae_ as its common English name (bearded vulture)
shows. There are also other forms, such as the South American _Harpyia_
and its allies, which though generally called eagles have been ranked as
buzzards. In the absence of any truly scientific definition of the
family _Aquilinae_ it is best to leave these and many other more or less
questionable members of the group--such as the genera _Spizaetus_,
_Circaetus_, _Spilornis_, _Helotarsus_, and so forth--and to treat here
of those whose position cannot be gainsaid.

[Illustration: FIG. 1.--Sea-Eagle.]

True eagles inhabit all the regions of the world, and some seven or
eight species at least are found in Europe, of which two are resident in
the British Islands. In England and in the Lowlands of Scotland eagles
only exist as stragglers; but in the Hebrides and some parts of the
Highlands a good many may yet be found, and their numbers appear to have
rather increased of late years than diminished; for the foresters and
shepherds, finding that a high price can be got for their eggs, take
care to protect the owners of the eyries, which are nearly all well
known, and to keep up the stock by allowing them at times to rear their
young. There are also now not a few occupiers of Scottish forests who
interfere so far as they can to protect the king of birds.[1] In Ireland
the extirpation of eagles seems to have been carried on almost
unaffected by the prudent considerations which in the northern kingdom
have operated so favourably for the race, and except in the wildest
parts of Donegal, Mayo and Kerry, eagles in the sister island are almost
birds of the past.

Of the two British species the erne (Icel. _Oern_) or sea-eagle (by some
called also the white-tailed and cinereous eagle)--_Haliaetus
albicilla_--affects chiefly the coast and neighbourhood of inland
waters, living in great part on the fish and refuse that is thrown up on
the shore, though it not unfrequently takes living prey, such as lambs,
hares and rabbits. On these last, indeed, young examples mostly feed
when they wander southward in autumn, as they yearly do, and appear in
England. The adults (fig. 1) are distinguished by their prevalent
greyish-brown colour, their pale head, yellow beak and white
tail--characters, however, wanting in the immature, which do not assume
the perfect plumage for some three or four years. The eyry is commonly
placed in a high cliff or on an island in a lake--sometimes on the
ground, at others in a tree--and consists of a vast mass of sticks in
the midst of which is formed a hollow lined with _Luzula sylvatica_ (as
first observed by John Wolley) or some similar grass, and here are laid
the two or three white eggs. In former days the sea-eagle seems to have
bred in several parts of England--as the Lake district, and possibly
even in the Isle of Wight and on Dartmoor. This species inhabits all the
northern part of the Old World from Iceland to Kamchatka, and breeds in
Europe so far to the southward as Albania. In the New World, however, it
is only found in Greenland, being elsewhere replaced by the white-headed
or bald eagle, _H. leucocephalus_, a bird of similar habits, and the
chosen emblem of the United States of America. In the far east of Asia
occurs a still larger and finer sea-eagle, _H. pelagicus_, remarkable
for its white thighs and upper wing-coverts. South-eastern Europe and
India furnish a much smaller species, _H. leucoryphus_, which has its
representative, _H. leucogaster_, in the Malay Archipelago and
Australia, and, as allies in South Africa and Madagascar, _H. vocifer_
and _H. vociferoides_ respectively. All these eagles may be
distinguished by their scaly tarsi, while the group next to be treated
of have the tarsi feathered to the toes.

[Illustration: FIG. 2.--Mountain-Eagle.]

The golden or mountain eagle, _Aquila chrysaetus_, is the second British
species. This also formerly inhabited England, and a nest, found in 1668
in the Peak of Derbyshire, is well described by Willughby, in whose time
it was said to breed also in the Snowdon range. It seldom if ever
frequents the coast, and is more active on the wing than the sea-eagle,
being able to take some birds as they fly, but a large part of its
sustenance is the flesh of animals that die a natural death. Its eyry is
generally placed and built like that of the other British species,[2]
but the neighbourhood of water is not requisite. The eggs, from two to
four in number, vary from a pure white to a mottled, and often highly
coloured, surface, on which appear different shades of red and purple.
The adult bird (fig. 2) is of a rich dark brown, with the elongated
feathers of the neck, especially on the nape, light tawny, in which
imagination sees a "golden" hue, and the tail marbled with brown and
ashy-grey. In the young the tail is white at the base, and the neck has
scarcely any tawny tint. The golden eagle does not occur in Iceland, but
occupies suitable situations over the rest of the Palaearctic Region and
a considerable portion of the Nearctic--though the American bird has
been, by some, considered a distinct species. Domesticated, it has many
times been trained to take prey for its master in Europe, and to this
species is thought to belong an eagle habitually used by the Kirghiz
Tatars, who call it _Bergut_ or _Bearcoot_, for the capture of
antelopes, foxes and wolves. It is carried hooded on horseback or on a
perch between two men, and released when the quarry is in sight. Such a
bird, when well trained, is valued, says P.S. Pallas, at the price of
two camels. It is quite possible, however, that more than one kind of
eagle is thus used, and the services of _A. heliaca_ (which is the
imperial eagle of some writers[3]) and of _A. mogilnik_--both of which
are found in central Asia, as well as in south-eastern Europe--may also
be employed.

A smaller form of eagle, which has usually gone under the name of _A.
naevia_, is now thought by the best authorities to include three local
races, or, in the eyes of some, species. They inhabit Europe, North
Africa and western Asia to India, and two examples of one of them--_A.
clanga_, the form which is somewhat plentiful in north-eastern
Germany--have occurred in Cornwall. The smallest true eagle is _A.
pennata_, which inhabits southern Europe, Africa and India. Differing
from other eagles of their genus by its wedge-shaped tail, though
otherwise greatly resembling them, is the _A. audax_ of Australia.
Lastly may be noticed here a small group of eagles, characterized by
their long legs, forming the genus _Nisaetus_, of which one species, _N.
fasciatus_, is found in Europe.      (A. N.)


FOOTNOTES:

  [1] Lord Breadalbane (d. 1871) was perhaps the first large landowner
    who set the example that has been since followed by others. On his
    unrivalled forest of Black Mount, eagles--elsewhere persecuted to the
    death--were by him ordered to be unmolested so long as they were not
    numerous enough to cause considerable depredations on the farmers'
    flocks. He thought that the spectacle of a soaring eagle was a
    fitting adjunct to the grandeur of his Argyllshire mountain scenery,
    and a good equivalent for the occasional loss of a lamb, or the
    slight deduction from the rent paid by his tenantry in consequence.

  [2] As already stated, the site chosen varies greatly. Occasionally
    placed in a niche in what passes for a perpendicular cliff to which
    access could only be gained by a skilful cragsman with a rope, the
    writer has known a nest to within 10 or 15 yds. of which he rode on a
    pony. Two beautiful views of as many golden eagles' nests, drawn on
    the spot by Joseph Wolf, are given in the _Ootheca Wolleyana_, and a
    fine series of eggs is also figured in the same work.

  [3] Which species may have been the traditional emblem of Roman
    power, and the _Ales Jovis_, is very uncertain.



EAGLEHAWK, a borough of Bendigo county, Victoria, Australia, 105 m. by
rail N.N.W. of Melbourne and 4 m. from Bendigo, with which it is
connected by steam tramway. Pop. (1901) 8130. It stands on the Bendigo
gold-bearing reef, and its mines are important.



EAGRE (a word of obscure origin; the earliest form seems to be _higre_,
Latinized as _higra_, which William of Malmesbury gives as the name of
the bore in the Severn; the _New English Dictionary_ rejects the usual
derivations from the O. Eng. _eagor_ or _egor_, which is seen in
compounds meaning "flood," and also the connexion with the Norse sea-god
_Aegir_), a tide wave of great height rushing up an estuary (see BORE),
used locally of the Humber and Trent.



EAKINS, THOMAS (1844-   ), American portrait and figure painter, was
born at Philadelphia, on the 25th of July 1844. A pupil of J.L. Gérôme,
in the École des Beaux-Arts, Paris, and Also of Léon Bonnat, besides
working in the studio of the sculptor Dumont, he became a prolific
portrait painter. He also painted genre pictures, sending to the
Centennial Exhibition at Philadelphia, in 1876, the "Chess Players," now
in the Metropolitan Museum of Art, New York. A large canvas, "The
Surgical Clinic of Professor Gross," owned by Jefferson Medical College,
Philadelphia, contains many life-sized figures. Eakins, with his pupil
Samuel Murray (b. 1870), modelled the heroic "Prophets" for the
Witherspoon Building, Philadelphia, and his work in painting has a
decided sculptural quality. He was for some years professor of anatomy
at the schools of the Pennsylvania Academy of Fine Arts in Philadelphia.
A man of great inventiveness, he experimented in many directions,
depicting on canvas modern athletic sports, the negro, and early
American life, but he is best known by his portraits. He received awards
at the Columbian (1893), Paris (1900), Pan-American (1900), and the St
Louis (1904), Expositions; and won the Temple medal in the Pennsylvania
Academy of Fine Arts, and the Proctor prize of the National Academy of
Design.



EALING, a municipal borough in the Ealing parliamentary division of
Middlesex, England, suburban to London, 9 m. W. of St Paul's cathedral.
Pop. (1891) 23,979; (1901) 33,031. The nucleus of the town, the ancient
village, lies south of the highroad to Uxbridge, west of the open Ealing
Common. The place is wholly residential. At St Mary's church, almost
wholly rebuilt c. 1870, are buried John Oldmixon, the historian (d.
1742), and Horne Tooke (d. 1812). The church of All Saints (1905)
commemorates Spencer Perceval, prime minister, who was assassinated in
the House of Commons in 1812. It was erected under the will of his
daughter Frederica, a resident of Ealing. Gunnersbury Park, south of
Ealing Common, is a handsome Italian mansion. Among former owners of the
property was Princess Amelia, daughter of George II., who lived here
from 1761 till her death in 1786. The name of Gunnersbury is said to be
traceable to the residence here of Gunilda, niece of King Canute. The
manor of Ealing early belonged to the see of London, but it is not
mentioned in Domesday and its history is obscure.



EAR (common Teut.; O.E. _éare_, Ger. _Ohr_, Du. _oor_, akin to Lat.
_auris_, Gr. [Greek: ous]), in anatomy, the organ of hearing. The human
ear is divided into three parts--external, middle and internal. The
external ear consists of the pinna and the external auditory meatus. The
pinna is composed of a yellow fibro-cartilaginous framework covered by
skin, and has an external and an internal or cranial surface. Round the
margin of the external surface in its upper three quarters is a rim
called the helix (fig. 1, a), in which is often seen a little prominence
known as Darwin's tubercle, representing the folded-over apex of a
prick-eared ancestor. Concentric with the helix and nearer the meatus is
the antihelix (c), which, above, divides into two limbs to enclose the
triangular fossa of the antihelix. Between the helix and the antihelix
is the fossa of the helix. In front of the antihelix is the deep fossa
known as the concha (fig. 1, d), and from the anterior part of this the
meatus passes inward into the skull. Overlapping the meatus from in
front is a flap called the tragus, and below and behind this is another
smaller flap, the antitragus. The lower part of the pinna is the lobule
(e), which contains no cartilage. On the cranial surface of the pinna
elevations correspond to the concha and to the fossae of the helix and
antihelix. The pinna can be slightly moved by the anterior, superior and
posterior auricular muscles, and in addition to these there are four
small intrinsic muscles on the external surface, known as the helicis
major and minor, the tragicus and the antitragicus, and two on the
internal surface called the obliquus and transversus. The external
auditory meatus (fig. 1, n) is a tube running at first forward and
upward, then a little backward and then forward and slightly downward;
of course all the time it is also running inward until the tympanic
membrane is reached. The tube is about an inch long, its outer third
being cartilaginous and its inner two-thirds bony. It is lined by skin
in its whole length, the sweat glands of which are modified to secrete
the wax or cerumen.

[Illustration: FIG. 1.--The Ear as seen in Section.

  a, Helix.                     m, Tip of petrous process.
  b, Antitragus.                n, External auditory meatus.
  c, Antihelix.                 o, Membrana tympani.
  d, Concha.                    p, Tympanum.
  e, Lobule.                    1, points to malleus.
  f, Mastoid process.           2, to incus.
  g, Portio dura.               3, to stapes.
  h, Styloid process.           4, to cochlea.
  k, Internal carotid artery.   5, 6, 7, the three semicircular canals.
  l, Eustachian tube.           8 and 9, facial and auditory nerves.]

The middle ear or tympanum (fig. 1, p) is a small cavity in the temporal
bone, the shape of which may perhaps be realized by imagining a hock
bottle subjected to lateral pressure in such a way that its circular
section becomes triangular, the base of the triangle being above. The
neck of the bottle, also laterally compressed, will represent the
Eustachian tube (fig. 1, l), which runs forward, inward and downward, to
open into the naso-pharynx, and so admits air into the tympanum. The
bottom of the bottle will represent the posterior wall of the tympanum,
from the upper part of which an opening leads backward into the mastoid
antrum and so into the air-cells of the mastoid process. Lower down is a
little pyramid which transmits the stapedius muscle, and at the base of
this is a small opening known as the iter chordae posterius, for the
chorda tympani to come through from the facial nerve. The roof is formed
by a very thin plate of bone, called the tegmen tympani, which separates
the cavity from the middle fossa of the skull. Below the roof the upper
part of the tympanum is somewhat constricted off from the rest, and to
this part the term "attic" is often applied. The floor is a mere groove
formed by the meeting of the external and internal walls. The outer wall
is largely occupied by the tympanic membrane (fig. 1, o), which entirely
separates the middle ear from the external auditory meatus; it is
circular, and so placed that it slopes from above, downward and inward,
and from behind, forward and inward. Externally it is lined by skin,
internally by mucous membrane, while between the two is a firm fibrous
membrane, convex inward about its centre to form the umbo. Just in front
of the membrane on the outer wall is the Glaserian fissure leading to
the glenoid cavity, and close to this is the canal of Huguier for the
chorda tympani nerve. The inner wall shows a promontory caused by the
cochlea and grooved by the tympanic plexus of nerves; above and behind
it is the fenestra ovalis, while below and behind the fenestra rotunda
is seen, closed by a membrane. Curving round, above and behind the
promontory and fenestrae, is a ridge caused by the aqueductus Fallopii
or canal for the facial nerve. The whole tympanum is about half an inch
from before backward, and half an inch high, and is spanned from side to
side by three small bones, of which the malleus (fig. 1, 1) is the most
external. This is attached by its handle to the umbo of the tympanic
membrane, while its head lies in the attic and articulates posteriorly
with the upper part of the next bone or incus (fig. 1, 2). The long
process of the incus runs downward and ends in a little knob called the
os orbiculare, which is jointed on to the stapes or stirrup bone (fig.
1, 3). The two branches of the stapes are anterior and posterior, while
the footplate fits into the fenestra ovalis and is bound to it by a
membrane. It will thus be seen that the stapes lies nearly at right
angles to the long process of the incus. From the front of the malleus a
slender process projects forward into the Glaserian fissure, while from
the back of the incus the posterior process is directed backward and is
attached to the posterior wall of the tympanum. These two processes form
a fulcrum by which the lever action of the malleus and incus is brought
about, so that when the handle of the malleus is pushed in by the
membrane the head moves out; the top of the incus, attached to it, also
moves out, and the os orbiculare moves in, and so the stapes is pressed
into the fenestra ovalis. The stapedius and tensor tympanic muscles, the
latter of which enters the tympanum in a canal just above the
Eustachian tube to be attached to the malleus, modify the movements of
the ossicles.

The mucous membrane lining the tympanum is continuous through the
Eustachian tube with that of the naso-pharynx, and is reflected on to
the ossicles, muscles and chorda tympani nerve. It is ciliated except
where it covers the membrana tympani, ossicles and promontory; here it
is stratified.

[Illustration: FIG. 2.--Diagram of the Membranous Labyrinth.

  DC, Ductus cochlearis.
  dr, Ductus reuniens.
  S, Sacculus.
  U, Utriculus.
  dv, Ductus endolymphaticus.
  SC, Semicircular canals.
         (After Waldeyer.)]

The internal ear or labyrinth consists of a bony and a membranous part,
the latter of which is contained in the former. The bony labyrinth is
composed of the vestibule, the semicircular canals and the cochlea. The
vestibule lies just internal to the posterior part of the tympanum, and
there would be a communication between the two, through the fenestra
ovalis, were it not that the footplate of the stapes blocks the way. The
inner wall of the vestibule is separated from the bottom of the internal
auditory meatus by a plate of bone pierced by many foramina for branches
of the auditory nerve (fig. 1, 9), while at the lower part is the
opening of the aqueductus vestibuli, by means of which a communication
is established with the posterior cranial fossa. Posteriorly the three
semicircular canals open into the vestibule; of these the external (fig.
1, 7) has two independent openings, but the superior and posterior (fig.
1, 5 and 6) join together at one end and so have a common opening, while
at their other ends they open separately. The three canals have
therefore five openings into the vestibule instead of six. One end of
each canal is dilated to form its ampulla. The superior semicircular
canal is vertical, and the two pillars of its arch are nearly external
and internal; the external canal is horizontal, its two pillars being
anterior and posterior, while the convexity of the arch of the posterior
canal is backward and its two pillars are superior and inferior.
Anteriorly the vestibule leads into the cochlea (fig. 1, 4), which is
twisted two and a half times round a central pillar called the modiolus,
the whole cochlea forming a rounded cone something like the shell of a
snail though it is only about 5 mm. from base to apex. Projecting from
the modiolus is a horizontal plate which runs round it from base to apex
like a spiral staircase; this is known as the lamina spiralis, and it
stretches nearly half-way across the canal of the cochlea. At the summit
it ends in a little hook named the hamulus. The modiolus is pierced by
canals which transmit branches of the auditory nerve to the lamina
spiralis.

[Illustration: FIG. 3.--cl, Columnar cells covering the crista acustica;
p, peripheral, and c, central processes of auditory cells; n, nerve
fibres. (After Rüdinger.)]

The membranous labyrinth lies in the bony labyrinth, but does not fill
it; between the two is the fluid called perilymph, while inside the
membranous labyrinth is the endolymph. In the bony vestibule lie two
membranous bags, the saccule (fig. 2, S) in front, and the utricle (fig.
2, U) behind; each of these has a special patch or macula to which twigs
of the auditory nerve are supplied, and in the mucous membrane of which
specialized hair cells are found (fig. 3, p).

Attached to the maculae are crystals of carbonate of lime called
otoconia. The membranous semicircular canals are very much smaller in
section than the bony; in the ampulla of each is a ridge, the crista
acustica, which is covered by a mucous membrane containing sensory hair
cells like those in the maculae. All the canals open into the utricle.
From the lower part of the saccule a small canal called the ductus
endolymphaticus (fig. 2, dv) runs into the aqueductus vestibuli; it is
soon joined by a small duct from the utricle, and ends, close to the
dura mater of the posterior fossa of the cranium, as the saccus
endolymphaticus, which may have minute perforations through which the
endolymph can pass. Anteriorly the saccule communicates with the
membranous cochlea or scala media by a short ductus reuniens (fig. 2,
dr). A section through each turn of the cochlea shows the bony lamina
spiralis, already noticed, which is continued right across the canal by
the basilar membrane (fig. 4, bm), thus cutting the canal into an upper
and lower half and connected with the outer wall by the strong spiral
ligament (fig. 4, sl). Near the free end of the lamina spiralis another
membrane called the membrane of Reissner (fig. 4, mR) is attached, and
runs outward and upward to the outer wall, taking a triangular slice out
of the upper half of the section. There are now three canals seen in
section, the upper of which is the scala vestibuli (fig. 4, SV), the
middle and outer the scala media, ductus cochlearis or true membranous
cochlea (fig. 4, DC), while the lower is the scala tympani (fig. 4, ST).
The scala vestibuli and scala tympani communicate at the apex of the
cochlea by an opening known as the helicotrema, so that the perilymph
can here pass from one canal to the other. At the base of the cochlea
the perilymph in the scala vestibuli is continuous with that in the
vestibule, but that in the scala tympani bathes the inner surface of the
membrane stretched across the fenestra rotunda, and also communicates
with the subarachnoid space through the aqueductus cochleae, which opens
into the posterior cranial fossa. The scala media containing endolymph
communicates, as has been shown, with the saccule through the canalis
reuniens, while, at the apex of the cochlea, it ends in a blind
extremity of considerable morphological interest called the lagena.

[Illustration: FIG. 4.--Transverse Section through the Tube of the
Cochlea.

  m, Modiolus.                 bm, Basilar membrane.
  0, Outer wall of cochlea.    cs, Crista spiralis.
  SV, Scala vestibuli.         sl, Spiral ligament.
  ST, Scala tympani.           sg, Spiral ganglion of auditory nerve.
  DC, Ductus cochlearis.       oc, Organ of Corti.
  mR, Membrane of Reissner.]

The scala media contains the essential organ of hearing or organ of
Corti (fig. 4, oc), which lies upon the inner part of the basilar
membrane; it consists of a tunnel bounded on each side of the inner and
outer rods of Corti; on each side of these are the inner and outer hair
cells, between the latter of which are found the supporting cells of
Deiters. Most externally are the large cells of Hensen. A delicate
membrane called the lamina reticularis covers the top of all these, and
is pierced by the hairs of the hair cells, while above this is the loose
membrana tectoria attached to the periosteum of the lamina spiralis,
near its tip, internally, and possibly to some of Deiter's cells
externally. The cochlear branch of the auditory nerve enters the lamina
spiralis, where a spiral ganglion (fig. 4, sg) is developed on it; after
this it is distributed to the inner and outer hair cells.

[Illustration: FIG. 5.--Transverse Section of Corti's Organ from the
Central Coil of Cochlea (Retzius).

(From R. Howden--Cunningham's _Text-Book of Anatomy_.)]

  For further details see _Text-Book of Anatomy_, edited by D.J.
  Cunningham (Edinburgh, 1906); Quain's _Elements of Anatomy_ (London,
  1893); Gray's _Anatomy_ (London, 1905); _A Treatise on Anatomy_,
  edited by H. Morris (London, 1902); _A Text-Book of Human Anatomy_, by
  A. Macalister (London, 1889).

_Embryology._--The pinna is formed from six tubercles which appear round
the dorsal end of the hyomandibular cleft or, more strictly speaking,
pouch. Those for the tragus and anterior part of the helix belong to the
first or mandibular arch, while those for the antitragus, antihelix and
lobule come from the second or hyoid arch. The tubercle for the helix is
dorsal to the end of the cleft where the two arches join. The external
auditory meatus, tympanum and Eustachian tube are remains of the
hyomandibular cleft, the membrana tympani being a remnant of the cleft
membrane and therefore lined by ectoderm outside and entoderm inside.
The origin of the ossicles is very doubtful. H. Gadow's view, which is
one of the latest, is that all three are derived from the hyomandibular
plate which connects the dorsal ends of the hyoid and mandibular bars
(_Anatomischer Anzeiger_, Bd. xix., 1901, p. 396). Other papers which
should be consulted are those of E. Gaupp, _Anatom. Hefte, Ergebnisse_,
Bd. 8, 1898, p. 991, and J.A. Hammar, _Archiv f. mikr. Anat._ lix.,
1902. These papers will give a clue to the immense literature of the
subject. The internal ear first appears as a pit from the cephalic
ectoderm, the mouth of which in Man and other mammals closes up, so that
a pear-shaped cavity is left. The stalk of the pear which is nearest the
point of invagination is called the recessus labyrinthi, and this, after
losing its connexion with the surface of the embryo, grows backward
toward the posterior cranial fossa and becomes the ductus
endolymphaticus. The lower part of the vesicle grows forward and becomes
the cochlea, while from the upper part three hollow circular plates grow
out, the central parts of which disappear, leaving the margin as the
semicircular canals. Subsequently constrictions appear in the vesicle
marking off the saccule and utricle. From the surrounding mesoderm the
petrous bone is formed by a process of chondrification and ossification.

  See W. His, Junr., _Archiv f. Anat. und Phys._, 1889, supplement, p.
  1; also Streeter, _Am. Journ. of Anat._ vi., 1907.

_Comparative Anatomy._--The ectodermal inpushing of the internal ear has
probably a common origin with the organs of the lateral line of fish. In
the lower forms the ductus endolymphaticus retains its communication
with the exterior on the dorsum of the head, and in some Elasmobranchs
the opening is wide enough to allow the passage of particles of sand
into the saccule. It is probable that this duct is the same which,
taking a different direction and losing its communication with the skin,
abuts on the posterior cranial fossa of higher forms (see Rudolf Krause,
"Die Entwickelung des Aq. vestibuli seu d. Endelymphaticus," _Anat.
Anzeiger_, Bd. xix., 1901, p. 49). In certain Teleostean fishes the swim
bladder forms a secondary communication with the internal ear by means
of special ossicles (see G. Ridewood, _Journ. Anat. & Phys._ vol.
xxvi.). Among the Cyclostomata the external semicircular canals are
wanting; Petromyzon has the superior and posterior only, while in Myxine
these two appear to be fused so that only one is seen. In higher types
the three canals are constant. Concretions of carbonate of lime are
present in the internal ears of almost all vertebrates; when these are
very small they are called otoconia, but when, as in most of the
teleostean fishes, they form huge concretions, they are spoken of as
otoliths. One shark, Squatina, has sand instead of otoconia (C. Stewart,
_Journ. Linn. Society_, xxix. 409). The utricle, saccule, semicircular
canals, ductus endolymphaticus and a short lagena are the only parts of
the ear present in fish.

The Amphibia have an important sensory area at the base of the lagena
known as the macula acustica basilaris, which is probably the first
rudiment of a true cochlea. The ductus endolymphaticus has lost its
communication with the skin, but it is frequently prolonged into the
skull and along the spinal canal, from which it protrudes, through the
intervertebral foramina, bulging into the coelom. This is the case in
the common frog (A. Coggi, _Anat. Anz._ 5. Jahrg., 1890, p. 177). In
this class the tympanum and Eustachian tube are first developed; the
membrana tympani lies flush with the skin of the side of the head, and
the sound-waves are transmitted from it to the internal ear by a single
bony rod--the columella.

In the Reptilia the internal ear passes through a great range of
development. In the Chelonia and Ophidia the cochlea is as rudimentary
as in the Amphibia, but in the higher forms (Crocodilia) there is a
lengthened and slightly twisted cochlea, at the end of which the lagena
forms a minute terminal appendage. At the same time indications of the
scalae tympani and vestibuli appear. As in the Amphibia the ductus
endolymphaticus sometimes extends into the cranial cavity and on into
other parts of the body. Snakes have no tympanic membrane. In the birds
the cochlea resembles that of the crocodiles, but the posterior
semicircular canal is above the superior where they join one another. In
certain lizards and birds (owls) a small fold of skin represents the
first appearance of an external ear. In the monotremes the internal ear
is reptilian in its arrangement, but above them the mammals always have
a spirally twisted cochlea, the number of turns varying from one and a
half in the Cetacea to nearly five in the rodent _Coelogenys_. The
lagena is reduced to a mere vestige. The organ of Corti is peculiar to
mammals, and the single columella of the middle ear is replaced by the
three ossicles already described in Man (see Alban Doran, "Morphology of
the Mammalian Ossicula auditus," _Proc. Linn. Soc._, 1876-1877, xiii.
185; also _Trans. Linn. Soc._ 2nd Ser. Zool. i. 371). In some mammals,
especially Carnivora, the middle ear is enlarged to form the tympanic
bulla, but the mastoid cells are peculiar to Man.

  For further details see G. Retzius, _Das Gehörorgan der Wirbelthiere_
  (Stockholm, 1881-1884); Catalogue of the Museum of the R. College of
  Surgeons--Physiological Series, vol. iii. (London, 1906); R.
  Wiedersheim's _Vergleichende Anatomie der Wirbeltiere_ (Jena, 1902).
       (F. G. P.)


DISEASES OF THE EAR

Modern scientific aural surgery and medicine (commonly known as Otology)
dates from the time of Sir William Wilde of Dublin (1843), whose work
marked a great advance in the application of anatomical, physiological
and therapeutical knowledge to the study of this organ. Less noticeable
contributions to the subject had not long before been made by Saunders
(1827), Kramer (1833), Pilcher (1841) and Yearsley (1841). The next
important event in the history of otology was the publication of J.
Toynbee's book in 1860 containing his valuable anatomical and
pathological observations. Von Tröltsch of Würzburg, following on the
lines of Wilde and Toynbee, produced two well-known works in 1861 and
1862, laying the foundation of the study in Germany. In that country and
in Austria he was followed by Hermann Schwartze, Politzer, Gruber,
Weber-Liel, Rüdinger, Moos and numerous others. France produced Itard,
de la Charrière, Menière, Loewenberg and Bonnafont; and Belgium, Charles
Delstanche, father and son. In Great Britain the work was carried on by
James Hinton (1874), Peter Allen (1871), Patterson Cassells and Sir
William Dalby. In America we may count among the early otologists Edward
H. Clarke (1858), D.B. St John Roosa, H. Knapp, Clarence J. Blake,
Albert H. Buck and Charles Burnett. Other workers all over the world are
too numerous to mention.

_Various Diseases and Injuries._--Diseases of the ear may affect any of
the three divisions, the external, middle or internal ear. The commoner
affections of the _auricle_ are eczema, various tumours (simple and
malignant), and serous and sebaceous cysts. Haematoma auris
(othaematoma), or effusion of blood into the auricle, is often due to
injury, but may occur spontaneously, especially in insane persons. The
chief diseases of the _external auditory canal_ are as follows:--impacted
cerumen (or wax), circumscribed (or furuncular) inflammation, diffuse
inflammation, strictures due to inflammatory affections, bony growths,
fungi (otomycosis), malignant disease, caries and necrosis, and foreign
bodies.

Diseases of the _middle ear_ fall into two categories, suppurative and
non-suppurative (i.e. with and without the formation of pus).
Suppurative inflammation of the middle ear is either acute or chronic,
and is in either case accompanied by perforation of the drum head and
discharge from the ear. The chief importance of these affections, in
addition to the symptoms of pain, deafness, discharge, &c., is the
serious complications which may ensue from their neglect, viz. aural
polypi, caries and necrosis of the bone, affections of the mastoid
process, including the mastoid antrum, paralysis of the facial nerve,
and the still more serious intracranial and vascular infective diseases,
such as abscess in the brain (cerebrum or cerebellum), meningitis, with
subdural and extradural abscesses, septic thrombosis of the sigmoid and
other venous sinuses, and pyaemia. It is owing to the possibility of
these complications that life insurance companies usually, and rightly,
inquire as to the presence of ear discharge before accepting a life.
Patterson Cassells of Glasgow urged this special point as long ago as
1877. Acute suppurative disease of the middle ear is often due to the
exanthemata, scarlatina, measles and smallpox, and to bathing and
diving. It may also be caused by influenza, diphtheria and pulmonary
phthisis.

Non-suppurative disease of the middle ear may be acute or chronic. In
the acute form the inflammation is less violent than in the acute
suppurative inflammation, and is rarely accompanied by perforation.
Chronic non-suppurative inflammation may be divided into the moist form,
in which the symptoms are improved by inflation of the tympanum through
the Eustachian tube, and the dry form (including sclerosis), which is
more intractable and in which this procedure has little or no beneficial
effect. Diseases of the _internal ear_ may be primary or secondary to an
affection of the tympanum or to intracranial disease.

Injuries to any part of the ear may occur, among the commoner being
injuries to the auricle, rupture of the drum head (from explosions,
blows on the ear or the introduction of sharp bodies into the ear
canal), and injuries from fractured skull. Congenital malformations of
the ear are most frequently met with in the auricle and external canal.

_Methods of Examination._--The methods of examining the ear are roughly
threefold:--(1) Testing the hearing with watch, voice and tuning-fork.
The latter is especially used to distinguish between disease of the
middle ear (conducting apparatus) and that of the internal ear
(perceptive apparatus). Our knowledge of the subject has been brought to
its present state by the labours of many observers, notably Weber,
Rinne, Schwabach, Lucae and Gellé. (2) Examination of the canal and
drum-head with speculum and reflector, introduced by Kramer, Wilde and
von Tröltsch. (3) Examination of the drum-cavity through the Eustachian
tube by the various methods of inflation.

_Symptoms._--The chief symptoms of ear diseases are deafness, noises in
the ear (tinnitus aurium), giddiness, pain and discharge. Deafness (or
other disturbance of hearing) and noises may occur from disease in
almost any part of the ear. Purulent discharge usually comes from the
middle ear. Giddiness is more commonly associated with affections of the
internal ear.

_Treatment._--Ear diseases are treated on ordinary surgical and medical
lines, due regard being had to the anatomical and physiological
peculiarities of this organ of sense, and especially to its close
relationship, on the one hand to the nose and naso-pharynx, and on the
other hand to the cranium and its contents. The chief advance in aural
surgery in recent years has been in the surgery of the mastoid process
and antrum. The pioneers of this work were H. Schwartze of Halle, and
Stacke of Erfurt, who have been followed by a host of workers in all
parts of the world. This development led to increased attention being
paid to the intracranial complications of suppurative ear disease, in
the treatment of which great strides have been made in the last few
years.

_Effects of Diseases of the Nose on the Ear._--The influence of diseases
of the nose and naso-pharynx on ear diseases was brought out by
Loewenberg of Paris, Voltolini of Breslau, and especially by Wilhelm
Meyer of Copenhagen, the discoverer of adenoid vegetations of the
naso-pharynx ("adenoids"), who recognized the great importance of this
disease and gave an inimitable account of it in the _Trans. of the Royal
Medical and Chirurgical Society of London_, 1870, and the _Archiv für
Ohrenheilkunde_, 1873. Adenoid vegetations, which consist of an abnormal
enlargement of Luschka's tonsil in the vault of the pharynx, frequently
give rise to ear disease in children, and, if not attended to, lay the
foundation of nasal and ear troubles in after life. They are often
associated with enlargement of the faucial tonsils.

  _Journals._--In 1864 the _Archiv für Ohrenheilkunde_ was started by
  Politzer and Schwartze, and, in 1867, the _Monatsschrift für
  Ohrenheilkunde_ (a monthly publication) was founded by Voltolini,
  Gruber, Weber-Liel and Rüdinger. Appearing first as the _Archives of
  Ophthalmology and Otology_, simultaneously in English and German, in
  1869, the _Archives of Otology_ became a separate publication under
  the editorship of Knapp, Moos and Roosa in 1879. Amongst other
  journals now existing are _Annales des maladies de l'oreille et du
  larynx_ (Paris), _Journal of Laryngology_ (London), _Centralblatt für
  Ohrenheilkunde_ (Leipzig), &c.

  _Societies._--The earliest society formed was the American Otological
  Society (1868), which held annual meetings and published yearly
  transactions. Flourishing societies for the study of otology
  (sometimes combined with laryngology) exist in almost all civilized
  countries, and they usually publish transactions consisting of
  original papers and cases. The Otological Society of the United
  Kingdom was founded in 1900.

  _International Congresses._--International Otological congresses have
  been held at intervals of about four years at New York, Milan, Basel,
  Brussels, Florence, London and Bordeaux (1904). The proceedings of the
  congresses appear as substantial volumes.

  _Hospitals._--The earliest record of a public institution for the
  treatment of ear diseases is a Dispensary for Diseases of the Eye and
  Ear in London, started by Saunders and Cooper, which existed in 1804;
  the aural part, however, was soon closed, so that the actual oldest
  institution appears to be the Royal Ear Hospital, London, which was
  founded by Curtis in 1816. Four years later there was started the New
  York Eye and Ear Infirmary. At the present time in every large town of
  Europe and America ear diseases are treated either in separate
  departments of general hospitals or in institutions especially devoted
  to the purpose.

  For a history of otology from the earliest times refer to _A Practical
  Treatise on the Diseases of the Ear_, by D.B. St John Roosa, M.D.,
  LL.D. (6th edition, New York, 1885), and for a general account of the
  present state of otological science to _A Text-Book of the Diseases of
  the Ear for Students and Practitioners_, by Professor Dr Adam
  Politzer, transl. by Milton J. Ballin, Ph.B., M.D., and Clarence J.
  Heller, M.D. (4th edition, London, 1902).     (E. C. B.*)



EARL, a title and rank of nobility (corresponding to Lat. _comes_; Fr.
_comte_), now the third in order of the British peerage, and accordingly
intervening between marquess and viscount. Earl, however, is the oldest
title and rank of English nobles, and was the highest until the year
1337, when the Black Prince was created duke of Cornwall by Edward III.

The nature of a modern earldom is readily understood, since it is a rank
and dignity of nobility which, while it confers no official power or
authority, is inalienable, indivisible, and descends in regular
succession to all the heirs under the limitation in the grant until, on
their failure, it becomes extinct.

The title is of Scandinavian origin, and first appears in England under
Canute as _jarl_, which was englished as _eorl_. Like the _ealdorman_,
whose place he took, the _eorl_ was a great royal officer, who might be
set over several counties, but who presided separately in the county
court of each with the bishop of the diocese. Although there were counts
in Normandy before the Norman Conquest, they differed in character from
the English earls, and the earl's position appears to have been but
slightly modified by the Conquest. He was still generally entitled to
the "third penny" of the county, but his office tended, under Norman
influence, to become an hereditary dignity and his sphere was restricted
by the Conqueror to a single county. The right to the "third penny" is a
question of some obscurity, but its possession seems to have been deemed
the distinctive mark of an earl, while the girding with "the sword of
the county" formed the essential feature in his creation or investiture,
as it continued to do for centuries later. The fact that every earl was
the earl of a particular county has been much obscured by the loose
usage of early times, when the style adopted was sometimes that of the
noble's surname (e.g. the Earls Ferrers), sometimes that of his chief
seat (e.g. the Earls of Arundel), and sometimes that of the county.
Palatine earldoms, or palatinates, were those which possessed _regalia_,
i.e. special privileges delegated by the crown. The two great examples,
which dated from Norman times, were Chester and Durham, where the earl
and the bishop respectively had their own courts and jurisdiction, and
were almost petty sovereigns.

The earliest known charter creating an earl is that by which Stephen
bestowed on Geoffrey de Mandeville, in or about 1140, the earldom of
Essex as an hereditary dignity. Several other creations by Stephen and
the empress Maud followed in quick succession. From at least the time of
the Conquest the earl had a double character; he was one of the
"barons," or tenants in chief, in virtue of the fief he held of the
crown, as well as an earl in virtue of his "belting" (with the sword)
and his "third penny" of the county. His fief would descend to the heirs
of his body; and the earliest charters creating earldoms were granted
with the same "limitation." The dignity might thus descend to a woman,
and, in that case, like the territorial fief, it would be held by her
husband, who might be summoned to parliament in right of it. The earldom
of Warwick thus passed through several families till it was finally
obtained, in 1449, by the Kingmaker, who had married the heiress of the
former earls. But in the case of "co-heiresses" (more daughters than
one), the king determined which, if any, should inherit the dignity.

The 14th century saw some changes introduced. The earldom of March,
created in 1328, was the first that was not named from a county or its
capital town. Under Edward III. also an idea appears to have arisen that
earldoms were connected with the tenure of lands, and in 1337 several
fresh ones were created and large grants of lands made for their
support. The first earldom granted with limitation to the heirs male of
the grantee's body was that of Nottingham in 1383. Another innovation
was the grant of the first earldom for life only in 1377. The girding
with the sword was the only observance at a creation till the first year
of Edward VI., when the imposition of the cap of dignity and a circlet
of gold was added. Under James I. the patent of creation was declared to
be sufficient without any ceremony. An earl's robe of estate has three
bars of ermine, but possibly it had originally four.

Something should be said of anomalous earldoms with Norman or Scottish
styles. The Norman styles originated either under the Norman kings or at
the time of the conquest of Normandy by the house of Lancaster. To the
former period belonged that of Aumale, which successive fresh creations,
under the Latinized form "Albemarle" have perpetuated to the present day
(see ALBEMARLE, EARLS AND DUKES OF). The so-called earls of Eu and of
Mortain, in that period, were really holders of Norman _comtés_. Henry
V. and his son created five or six, it is said, but really seven at
least, Norman countships or earldoms, of which Harcourt (1418), Perche
(1419), Dreux (1427) and Mortain (? 1430) were bestowed on English
nobles, Eu (1419), and Tankerville (1419) on English commoners, and
Longueville (1419) on a foreigner, Gaston de Foix. Of these the earldom
of "Eu" was assumed by the earls of Essex till the death of Robert, the
parliament's general (1646), while the title of Tankerville still
survives under a modern creation (1714). An anomalous royal licence of
1661 permitted the earl of Bath to use the title of earl of Corbeil by
alleged hereditary right. Of Scottish earldoms recognized in the English
parliament the most remarkable case is that of the Lords Umfraville, who
were summoned for three generations (1297-1380), as earls of Angus;
Henry, Lord Beaumont, also was summoned as earl of Buchan from 1334 to
1339.

The earldom of Chester is granted to the princes of Wales on their
creation, and the Scottish earldom of Carrick is held by the eldest son
of the sovereign under act of parliament.

The premier earldom is that of Arundel (q.v.), but as this is at present
united with the dukedom of Norfolk, the oldest earldom not merged in a
higher title is that of Shrewsbury (1442), the next in seniority being
Derby (1485), and Huntingdon (1529). These three have been known as "the
catskin earls," a term of uncertain origin. The ancient earldom of
Wiltshire (1397) was unsuccessfully claimed in 1869 by Mr Scrope of
Danby, and that of Norfolk (1312), in 1906, by Lord Mowbray and
Stourton.

The premier earldom of Scotland as recognized by the Union Roll (1707),
is that of Crawford, held by the Lindsays since its creation in 1398;
but it is not one of the ancient "seven earldoms." The Decreet of
Ranking (1606) appears to have recognized the earldom of Sutherland as
the most ancient in virtue of a charter of 1347, but the House of Lords'
decision of 1771 recognized it as having descended from at least the
year 1275, and it may be as old as 1228. It is at present united with
the dukedom of Sutherland. The original "seven earldoms" (of which it
was one) represented seven provinces, each of which was under a
"_mormaer_." This Celtic title was rendered "_jarl_" by the Norsemen,
and under Alexander I. (c. 1115) began to be replaced by earl (_comes_),
owing to Anglo-Norman influence, which also tended to make these
earldoms less official and more feudal.

In Ireland the duke of Leinster is, as earl of Kildare, premier earl as
well as premier duke.

An earl is "Right Honourable," and is styled "My Lord." His eldest son
bears his father's "second title," and therefore, that second title
being in most cases a viscounty, he generally is styled "Viscount";
where, as with Devon and Huntingdon, there is no second title, one may
be assumed for convenience; under all circumstances, however, the eldest
son of an earl takes precedence immediately after the viscounts. The
younger sons of earls are "Honourable," but all their daughters are
"Ladies." In formal documents and instruments, the sovereign, when
addressing or making mention of any peer of the degree of an earl,
usually designates him "trusty and well-beloved cousin,"--a form of
appellation first adopted by Henry IV., who either by descent or
alliance was actually related to every earl and duke in the realm. The
wife of an earl is a countess; she is "Right Honourable," and is styled
"My Lady." For the earl's coronet see CROWN AND CORONET.

  See Lord's _Reports on the Dignity of a Peer_; Pike's _Constitutional_
  _History of the House of Lords_; Selden's _Titles of Honour_; G.E.
  C(okayne)'s _Complete Peerage_; Round's _Geoffrey de Mandeville_.
       (J. H. R.)



EARLE, JOHN (c. 1601-1665), English divine, was born at York about 1601.
He matriculated at Christ Church, Oxford, but migrated to Merton, where
he obtained a fellowship. In 1631 he was proctor and also chaplain to
Philip, earl of Pembroke, then chancellor of the university, who
presented him to the rectory of Bishopston in Wiltshire. His fame
spread, and in 1641 he was appointed chaplain and tutor to Prince
Charles. In 1643 he was elected one of the Assembly of Divines at
Westminster, but his sympathies with the king and with the Anglican
Church were so strong that he declined to sit. Early in 1643 he was
chosen chancellor of the cathedral of Salisbury, but of this preferment
he was soon deprived as a "malignant." After Cromwell's great victory at
Worcester, Earle went abroad, and was named clerk of the closet and
chaplain to Charles II. He spent a year at Antwerp in the house of Isaac
Walton's friend, George Morley, who afterwards became bishop of
Winchester. He next joined the duke of York (James II.) at Paris,
returning to England at the Restoration. He was at once appointed dean
of Westminster, and in 1661 was one of the commissioners for revising
the liturgy. He was on friendly terms with Richard Baxter. In November
1662 he was consecrated bishop of Worcester, and was translated, ten
months later, to the see of Salisbury, where he conciliated the
nonconformists. He was strongly opposed to the Conventicle and Five Mile
Acts. During the great plague Earle attended the king and queen at
Oxford, and there he died on the 17th of November 1665.

Earle's chief title to remembrance is his witty and humorous work
entitled _Microcosmographie, or a Peece of the World discovered, in
Essayes and Characters_, which throws light on the manners of the time.
First published anonymously in 1628, it became very popular, and ran
through ten editions in the lifetime of the author. The style is quaint
and epigrammatic; and the reader is frequently reminded of Thomas Fuller
by such passages as this: "A university dunner is a gentlemen follower
cheaply purchased, for his own money has hyr'd him." Several reprints of
the book have been issued since the author's death; and in 1671 a French
translation by J. Dymock appeared with the title of _Le Vice ridiculé_.
Earle was employed by Charles II. to make the Latin translation of the
_Eikon Basilike_, published in 1649. A similar translation of R.
Hooker's _Ecclesiastical Polity_ was accidentally destroyed.

"Dr Earle," says Lord Clarendon in his _Life_, "was a man of great piety
and devotion, a most eloquent and powerful preacher, and of a
conversation so pleasant and delightful, so very innocent, and so very
facetious, that no man's company was more desired and loved. No man was
more negligent in his dress and habit and mien, no man more wary and
cultivated in his behaviour and discourse. He was very dear to the Lord
Falkland, with whom he spent as much time as he could make his own."

  See especially Philip Bliss's edition of the _Microcosmographie_
  (London, 1811), and E. Arber's Reprint (London, 1868).



EARLE, RALPH (1751-1801), American historical and portrait painter, was
born at Leicester, Massachusetts, on the 11th of May 1751. Like so many
of the colonial craftsmen, Earle was self-taught, and for many years was
an itinerant painter. He went with the Governor's Guard to Lexington and
made battle sketches, from which in 1775 he painted four scenes,
engraved by Amos Doolittle, which are probably the first historical
paintings by an American. After the War of Independence, Earle went to
London, entered the studio of Benjamin West, and painted the king and
many notables. After his return to America in 1786 he made portraits of
Timothy Dwight, Governor Caleb Strong, Roger Sherman, and other
prominent men. He also painted a large picture of Niagara Falls. He died
at Bolton, Connecticut, on the 16th of August 1801.



EARL MARSHAL, in England, a functionary who ranks as the eighth of the
great officers of state. He is the head of the college of arms, and has
the appointment of the kings-of-arms, heralds and pursuivants at his
discretion. He attends the sovereign in opening and closing the session
of parliament, walking opposite to the lord great chamberlain on his or
her right hand. It is his duty to make arrangements for the order of all
state processions and ceremonials, especially for coronations and royal
marriages and funerals. Like the lord high constable he rode into
Westminster Hall with the champion after a coronation, till the
coronation banquet was abandoned, taking his place on the left hand, and
with the lord great chamberlain he assists at the introduction of all
newly-created peers into the House of Lords.

The marshal appears in the feudal armies to have been in command of the
cavalry under the constable, and to have in some measure superseded him
as master of the horse in the royal palace. He exercised joint and
co-ordinate jurisdiction with the constable in the court of chivalry,
and afterwards became the sole judge of that tribunal till its
obsolescence. The marshalship of England was formerly believed to have
been inherited from the Clares by the Marshal family, who had only been
marshals of the household. It was held, however, by the latter family,
as the office of chief (_magister_) marshal, as early as the days of
Henry I. Through them, under Henry III., it passed to the Bigods, as
their eldest co-heirs. In 1306 it fell to the crown on the death of the
last Bigod, earl of Norfolk, who had made Edward I. his heir, and in
1316 it was granted by Edward II. to his own younger brother, Thomas "of
Brotherton," earl of Norfolk. As yet the style of the office was only
"marshal" although the last Bigod holder, being an earl, was sometimes
loosely spoken of as the earl marshal. The office, having reverted to
the crown, was granted out anew by Richard II., in 1385, to Thomas
Mowbray, earl of Nottingham, the representative of Thomas "of
Brotherton." In 1386 the style of "earl marshal" was formally granted to
him in addition. After several attainders and partial restorations in
the reigns of the Tudors and the Stuarts, the earl marshalship was
granted anew to the Howards by Charles II. in 1672 and entailed on their
male line, with many specific remainders and limitations, under which
settlement it has regularly descended to the present duke of Norfolk.
Its holders, however, could not execute the office until the Roman
Catholic emancipation, and had to appoint deputies. The duke is styled
earl marshal "and hereditary marshal of England," but the double style
would seem to be an error, though the Mowbrays, with their double
creation (1385, 1386) might have claimed it. His Grace appends the
letters "E.M." to his signature, and bears behind his shield two batons
crossed in saltire, the marshal's rod (_virga_) having been the badge of
the office from Norman times. There appear to have been hereditary
marshals of Ireland, but their history is not well ascertained. The
Keiths were Great Marischals of Scotland from at least the days of
Robert Bruce, and were created earls marischal in or about 1458, but
lost both earldom and office by the attainder of George, the 10th earl,
in 1716. (See also MARSHAL; STATE, GREAT OFFICERS OF.)

  See "The Marshalship of England," in J.H. Round, _Commune of London
  and Other Studies_ (London, 1899); G.E. C(okayne)'s _Complete
  Peerage_.     (J. H. R.)



EARLOM, RICHARD (1742-1822), English mezzotint engraver, was born and
died in London. His natural faculty for art appears to have been first
called into exercise by admiration for the lord mayor's state coach,
just decorated by Cipriani. He tried to copy the paintings, and was sent
to study under Cipriani. He displayed great skill as a draughtsman, and
at the same time acquired without assistance the art of engraving in
mezzotint. In 1765 he was employed by Alderman Boydell, then one of the
most liberal promoters of the fine arts, to make a series of drawings
from the pictures at Houghton Hall; and these he afterwards engraved in
mezzotint. His most perfect works as engraver are perhaps the fruit and
flower pieces after the Dutch artists Van Os and Van Huysum. Amongst his
historical and figure subjects are--"Agrippina," after West; "Love in
Bondage," after Guido Reni; the "Royal Academy," the "Embassy of
Hyderbeck to meet Lord Cornwallis," and a "Tiger Hunt," the last three
after Zoffany; and "Lord Heathfield," after Sir Joshua Reynolds. Earlom
also executed a series of 200 facsimiles of the drawings and sketches
of Claude Lorraine, which was published in 3 vols. folio, under the
title of _Liber veritatis_ (1777-1819).



EARLSTON (formerly ERCILDOUNE, of which it is a corruption), a parish
and market town of Berwickshire, Scotland. Pop. (1901) 1049. It is
situated on Leader Water in Lauderdale, 72½ m. S.E. of Edinburgh by the
North British railway branch line from Reston Junction to St Boswells,
and about 4 m. N.E. of Melrose. When the place was a hamlet of rude huts
it was called Arcioldun or "Prospect Fort," with reference to Black Hill
(1003 ft.), on the top of which may yet be traced the concentric rings
of the British fort by which it was crowned. It is said to be possible
to make out the remains of the cave-dwellings of the Ottadeni, the
aborigines of the district. In the 12th and 13th centuries the Lindsays
and the earls of March and Dunbar were the chief baronial families. The
particular link with the remote past, however, is the ivy-clad ruin of
the ancient tower, "The Rhymer's Castle," the traditional residence of
Thomas Learmont, commonly called Thomas of Ercildoune, or Thomas the
Rhymer, poet and prophet, and friend of the Fairies, who was born here
about 1225. Rhymer's Tower was crumbling to pieces, and its stones were
being used in the erection of dykes, cottages and houses, when the
Edinburgh Border Counties Association acquired the relic and surrounding
lands in 1895, and took steps to prevent further spoliation and decay.
The leading manufactures are ginghams, tweeds and shirtings, and the
town is also an important agricultural centre, stock sales taking place
at regular intervals and cattle and horse fairs being held every year.
Some 3 m. away is the estate of Bemersyde, said to have been in the
possession of the Haigs for nearly 1000 years. The prospect from
Bemersyde Hill was Sir Walter Scott's favourite view. The castle at
Bemersyde was erected in 1535 to secure the peace of the Border.



EARLY, JUBAL ANDERSON (1816-1894), American soldier and lawyer, was born
in Franklin county, Virginia, on the 3rd of November 1816, and graduated
at the U.S. Military Academy in 1837. He served in the Seminole War of
1837-38, after which he resigned in order to practise law in Franklin
county, Va. He also engaged in state politics, and served in the Mexican
War as a major of Virginia volunteers. He was strongly opposed to
secession, but thought it his duty to conform to the action of his
state. As a colonel in the Confederate army, he rendered conspicuous
service at the first battle of Bull Run (q.v.). Promoted
brigadier-general, and subsequently major-general, Early served
throughout the Virginian campaigns of 1862-63, and defended the lines of
Fredericksburg during the battle of Chancellorsville. At Gettysburg he
commanded his division of Ewell's corps. In the campaign of 1864 Early,
who had now reached the rank of lieutenant-general, commanded the
Confederate forces in the Shenandoah Valley. The action of Lynchburg
left him free to move northwards, his opponent being compelled to march
away from the Valley. Early promptly utilized his advantage, crossed the
Potomac, and defeated, on the Monocacy, all the troops which could be
gathered to meet him. He appeared before the lines of Washington, put
part of Maryland and Pennsylvania under contribution, and only retired
to the Valley when threatened by heavy forces hurriedly sent up to
Washington. He then fought a successful action at Winchester, reappeared
on the Potomac, and sent his cavalry on a raid into Pennsylvania. A
greatly superior army was now formed under General Sheridan to oppose
Early. In spite of his skill and energy the Confederate leader was
defeated in the battles of Winchester and Fisher's Hill. Finally, on the
19th of October, after inflicting at first a severe blow upon the
Federal army in its camps on Cedar Creek, he was decisively beaten by
Sheridan. (See SHENANDOAH VALLEY CAMPAIGNS.) Waynesboro (March 1865) was
his last fight, after which he was relieved from his command. General
Early was regarded by many as the ablest soldier, after Lee and Jackson,
in the Army of Northern Virginia, and one of the ablest in the whole
Confederate army. That he failed to make headway against an army far
superior in numbers, and led by a general of the calibre of Sheridan,
cannot be held to prove the falsity of this judgment. After the peace
he went to Canada, but in 1867 returned to resume the practice of law.
For a time he managed in conjunction with General Beauregard the
Louisiana lottery. He died at Lynchburg, Va., on the 2nd of March 1894.
General Early was for a time president of the Southern Historical
Society, and wrote, besides various essays and historical papers, _A
Memoir of the Last Year of the War, &c._ (1867).



EARLY ENGLISH PERIOD, in architecture, the term given by Rickman to the
first pointed or Gothic style in England, nominally 1189-1307, which
succeeded the Romanesque or Norman period towards the end of the 12th
century, and developed into the Decorated period in the commencement of
the 14th century. It is chiefly characterized by the almost universal
employment of the pointed arch, not only in arches of wide span such as
those of the nave arcade, but for doorways and windows. The actual
introduction of the pointed arch took place at a much earlier date, as
in the nave arcade of the Cistercian Abbey of Buildwas (1140), though
the clerestory window above has semicircular arches. It is customary,
therefore, to make allowance for a transitional epoch from the middle of
the 12th century. Although the pointed arches used are sometimes
equilateral and sometimes drop-arches, the lancet-arch is the most
characteristic. The period is best recognized in England by the great
depth given to the hollows of the mouldings, alternating with fillets
and rolls, by the decoration of the hollows with the dog-tooth ornament,
by the circular abacus of the capitals, and the employment of slender
detached shafts of Purbeck marble which are attached to piers by
circular moulded shaft-rings (Fr. _anneau_).

The arches are sometimes cusped; circles with trefoils, quatrefoils,
&c., are introduced into the tracery, and large rose windows in the
transept or nave, as at Lincoln (1220). The conventional foliage
decorating the capitals is of great beauty and variety, and extends to
spandrils, bosses, &c. In the spandrils of the arches of the nave,
transept or choir arcades, diaper work is occasionally found, as in the
transept of Westminster Abbey. The latter is one of the chief examples
of the period, to which must be added the cathedral of Salisbury (except
the tower); the Galilee at Ely; nave and transept of Wells (1225-1240);
nave of Lincoln; west front of Peterborough; and the minster at
Beverley.     (R. P. S.)



EARN, the name of a loch and river in Perthshire, Scotland. The loch,
lying almost due east and west, is 6½ m. long and {4/5} m. in maximum
breadth, 287 ft. deep, with a mean depth of 138 ft., covers an area of
nearly 4 sq. m., has a drainage basin of over 54½ sq. m., and stands 317
ft. above the sea. Its waters are said never to freeze. It discharges by
the river Earn. The points of interest on its shores are Lochearnhead
(at the southern extremity of Glen Ogle), which has a station on the
Callander-Oban railway, and the ruins of St Blane's chapel; Edinample
Castle, an old turreted mansion belonging to the marquess of
Breadalbane, situated in well-wooded grounds near the pretty falls of
the Ample; Ardvorlich House, the original of Darlinvarach in Scott's
_Legend of Montrose_, and the village of St Fillans at the foot of the
loch, once the terminus of the branch of the Caledonian railway from
Perth. The river flows out of Loch Earn, pursues an eastward course with
a gentle inclination towards the south, and reaches the Firth of Tay, 6½
m. below Perth, after a total run of 49 m. Its chief tributaries on the
right are the Ruchil, Machany, Ruthven, May and Farg, and on the left,
the Lednock and Turret. It is navigable by vessels of 50 tons as far up
as Bridge of Earn, and is a notable fishing stream, abounding with
salmon and trout, perch and pike being also plentiful. On the Lednock
are the falls of the Devil's Cauldron and on the Turret and its feeders
several graceful cascades. The principal places of interest on the banks
of the Earn are Dunira, the favourite seat of Henry Dundas, 1st Viscount
Melville, who took the title of his barony from the estate and to whose
memory an obelisk was raised on the adjoining hill of Dunmore; the
village of Comrie; the town of Crieff; the ruined castle of
Innerpeffray, founded in 1610 by the 1st Lord Maderty, close to which is
the library founded in 1691 by the 3rd Lord Maderty, containing some
rare black-letter books and the Bible that belonged to the marquess of
Montrose; Gascon Hall, now in ruins, but with traditions reaching back
to the days of Wallace; Dupplin Castle, a fine Tudor mansion, seat of
the earl of Kinnoull, who derives from it the title of his viscounty;
Aberdalgie, Forgandenny and Bridge of Earn, a health resort situated
amidst picturesque surroundings. Strathearn, as the valley of the Earn
is called, extending from the loch to the Firth of Tay, is a beautiful
and, on the whole, fertile tract, though liable at times to heavy
floods. The earl of Perth is hereditary steward of Strathearn.



EARNEST (probably a corruption of the obsolete _arles_ or _erles_,
adapted from Lat. equivalent _arrha_, due to a confusion with the
adjective "earnest," serious, O. Eng. _eornust_, cognate with Ger.
_ernst_), the payment of a sum of money by the buyer of goods to the
seller on the conclusion of a bargain as a pledge for its due
performance. It is almost similar to the _arrha_ of the Roman law, which
may be traced back in the history of legal institutions to a period when
the validity of a contract depended not so much upon the real intention
of the parties, as upon the due observance of a prescribed ceremony. But
_earnest_ was never part payment, which _arrha_ might have been. Apart
from its survival as a custom, its chief importance in English law is
its recognition by the Statute of Frauds as giving validity to contracts
for the sale of goods of a value exceeding £10 (see SALE OF GOODS). It
is in that statute clearly distinguished from part payment, consequently
any sum, however small, would be sufficient as earnest, being given as a
token that the contract is binding and should be expressly stated so by
the giver. The giving of earnest, or _hand-money_, as it is sometimes
called, has now fallen into very general disuse.



EAR-RING, an ornament worn pendent from the ear, and generally suspended
(especially among the more civilized races) by means of a ring or hook
passing through the pendulous lobe of the ear. Among savage races the
impulse to decorate, or at any rate to modify the appearance of the ear,
is almost universal. With such peoples the ear appendage is chiefly
remarkable for its extravagant dimensions. Many examples may be seen in
the ethnographic galleries of the British Museum. The Berawan people of
Borneo use plugs through the lobe of the ear 3¾ in. in diameter. More
extraordinary still is an example of a stone ear-plug worn by a Masai,
4½ in. in diameter and weighing 2 lb. 14 oz. (_Man_, 1905, p. 22). It is
stated that according to the Masai standard of fashion, the lobes of the
ears should be enlarged so as to be capable of meeting above the head.
Among the superior races, though ear ornaments of extravagant size and
elaboration are not unknown, moderation in size is commonly observed,
and greater attention is paid to workmanship and fineness of material.

The general usage appears to have been to have ear-rings worn in pairs,
the two ornaments in all respects resembling each other; in ancient
times, or more recently among Oriental races, a single ear-ring has
sometimes been worn. The use of this kind of ornament, which constantly
was of great value, dates from the remotest historical antiquity, the
earliest mention of ear-rings occurring in the book of Genesis. It
appears probable that the ear-rings of Jacob's family, which he buried
with his strange idols at Bethel, were regarded as amulets or talismans,
such unquestionably being the estimation in which some ornaments of this
class have been held from a very early period, as they still are held in
the East. Thus in New Zealand ear-rings are decorated with the teeth of
enemies, and with talismanic sharks' teeth. Among all the Oriental races
of whom we have any accurate knowledge, the Hebrews and Egyptians
excepted, ear-rings always have been in general use by both sexes; while
in the West, as well as by the Hebrews and Egyptians, as a general rule
they have been considered exclusively female ornaments. By the Greeks
and Romans also ear-rings were worn only by women, and the wearing of
them by a man is often spoken of as distinctively oriental.

[Illustration: From _La Grande Encyclopédie_.

FIG. 1.--Ear-ring from an Assyrian bas relief.]

In archaic art, ear-rings are frequently represented or their traces are
left in the perforated ear lobes of early statues. After the 4th century
such perforations occur seldom. In one instance, a Greek inscription
records the weight of the detachable gold ornaments on a statue, among
which a pair of ear-rings is included. Ear-rings of characteristic form
are frequently discovered by excavation. In Egypt, a system of pendent
chains is found hanging from a disk. In Assyria the decoration consists
of pendants or knobs attached to a rigid ring. In the early civilization
represented by Dr Schliemann's Trojan investigations, pieces of gold
plate are suspended by parallel chains. In the Mycenaean period,
ear-rings are infrequent in Greece, but have been found in abundance in
the Mycenaean finds of Enkomi (Cyprus) in the form of pendent
bulls'-heads, or of decorative forms based on the bull's head. In the
tombs of the Greek settlers in the Crimea (4th century B.C.), ear-rings
are found of marvellous complexity and beauty. The lexicographer Pollux,
speaking of the names given to ear-rings, derived from their forms,
mentions caryatids, hippocamps and centauresses. Jewels of the same
class, of exquisite beauty and of workmanship that is truly wonderful,
have been rescued from the sepulchres of ancient Etruria. Ear-rings of
comparatively simple forms, but set with pearls and other stones, were
the mode in Rome. In some instances, the stones were of fabulous value.
During the Byzantine period they once more attained an extravagant size.
Researches among the burial places of Anglo-Saxon Britain have led to
the discovery of jewels in considerable numbers, which among their
varieties include ear-rings executed in a style that proves the
Anglo-Saxons to have made no inconsiderable advances in the arts of
civilization.

[Illustration: From _La Grande Encyclopédie_.

FIG. 2.--Thetis crossing the sea, with the armour of Achilles. Ear-ring
from the Crimea, Hermitage museum.]

These same ornaments, which never have fallen into disuse, enjoy at the
present day a considerable degree of favour, and the tide of fashion has
set towards their increased use. Like all other modern jewels, however,
the ear-rings of our own times as works of art can claim no historical
attributes, because they consist as well of reproductions from all past
ages and of every race as of fanciful productions that certainly can be
assigned to no style of art whatever. As one of the curiosities of the
subject it may be mentioned that Antonia, wife of Drusus, is said by
Pliny to have attached a pair of ear-rings to her pet lamprey.



EARTH (a word common to Teutonic languages, cf. Ger. _Erde_, Dutch
_aarde_, Swed. and Dan. _jord_; outside Teutonic it appears only in the
Gr. [Greek: eraze], on the ground; it has been connected by some
etymologists with the Aryan root _ar-_, to plough, which is seen in the
Lat. _arare_, obsolete Eng. "ear," and Gr. [Greek: aroun], but this is
now considered very doubtful; see G. Curtius, _Greek Etymology_, Eng.
trans., i. 426; Max Müller, _Lectures_, 8th ed. i. 294). From early
times the word "earth" has been used in several connexions--from that of
soil or ground to that of the planet which we inhabit, but it is
difficult to trace the exact historic sequence of the diverse usages. In
the cosmogony of the Pythagoreans, Platonists and other philosophers,
the term or its equivalent denoted an element or fundamental quality
which conferred upon matter the character of earthiness; and in the
subsequent development of theories as to the ultimate composition of
matter by the alchemists, iatrochemists, and early phlogistonists an
element of the same name was retained (see ELEMENT). In modern
chemistry, the common term "earth" is applied to certain oxides:--the
"alkaline earths" (q.v.) are the oxides of calcium (lime), barium
(baryta) and strontium (strontia); the "rare earths" (q.v.) are the
oxides of a certain class of rare metals.


THE EARTH

The terrestrial globe is a member of the Solar system, the third in
distance from the Sun, and the largest within the orbit of Jupiter. In
the wider sense it may be regarded as composed of a gaseous atmosphere
(see METEOROLOGY), which encircles the crust or lithosphere (see
GEOGRAPHY), and surface waters or hydrosphere (see OCEAN AND
OCEANOGRAPHY). The description of the surface features is a branch of
Geography, and the discussions as to their origin and permanence belongs
to Physiography (in the narrower sense), physiographical geology, or
physical geography. The investigation of the crust belongs to geology
and of rocks in particular to petrology.

In the present article we shall treat the subject matter of the Earth as
a planet under the following headings:--(1) Figure and Size, (2) Mass
and Density, (3) Astronomical Relations, (4) Evolution and Age. These
subjects will be treated summarily, readers being referred to the
article ASTRONOMY and to the cross-references for details.

1. _Figure and Size._--To primitive man the Earth was a flat disk with
its surface diversified by mountains, rivers and seas. In many
cosmogonies this disk was encircled by waters, unmeasurable by man and
extending to a junction with the sky; and the disk stood as an island
rising up through the waters from the floor of the universe, or was
borne as an immovable ship on the surface. Of such a nature was the
cosmogony of the Babylonians and Hebrews; Homer states the same idea,
naming the encircling waters [Greek: Ôkeanos]; and Hesiod regarded it as
a disk midway between the sky and the infernal regions. The theory that
the Earth extended downwards to the limit of the universe was subjected
to modification when it was seen that the same sun and stars reappeared
in the east after their setting in the west. But man slowly realized
that the earth was isolated in space, floating freely as a balloon, and
much speculation was associated about that which supported the Earth.
Tunnels in the foundations to permit the passage of the sun and stars
were suggested; the Greeks considered twelve columns to support the
heavens, and in their mythology the god Atlas appears condemned to
support the columns; while the Egyptians had the Earth supported by four
elephants, which themselves stood on a tortoise swimming on a sea.
Earthquakes were regarded as due to a movement of these foundations; in
Japan this was considered to be due to the motion of a great spider, an
animal subsequently replaced by a cat-fish; in Mongolia it is a hog; in
India, a mole; in some parts of South America, a whale; and among some
of the North American Indians, a giant tortoise.

The doctrine of the spherical form has been erroneously assigned to
Thales; but he accepted the Semitic conception of the disk, and regarded
the production of springs after earthquakes as due to the inrushing of
the waters under the Earth into fissures in the surface. His pupil,
Anaximander (610-547), according to Diogenes Laërtius, believed it to be
spherical (see _The Observatory_, 1894, P. 208); and Anaximenes probably
held a similar view. The spherical form is undoubtedly a discovery of
Pythagoras, and was taught by the Pythagoreans and by the Eleatic
Parmenides. The expositor of greatest moment was Aristotle; his
arguments are those which we employ to-day:--the ship gradually
disappearing from hull to mast as it recedes from the harbour to the
horizon; the circular shadow cast by the Earth on the Moon during an
eclipse, and the alteration in the appearance of the heavens as one
passes from point to point on the Earth's surface.[1] He records
attempts made to determine the circumference; but the first scientific
investigation in this direction was made 150 years later by
Eratosthenes. The spherical form, however, only became generally
accepted after the Earth's circumnavigation (see GEOGRAPHY).

The historical development of the methods for determining the figure of
the Earth (by which we mean a theoretical surface in part indicated by
the ocean at rest, and in other parts by the level to which water freely
communicating with the oceans by canals traversing the land masses would
rise) and the mathematical investigation of this problem are treated in
the articles EARTH, FIGURE OF THE, and GEODESY; here the results are
summarized. Sir Isaac Newton deduced from the mechanical consideration
of the figure of equilibrium of a mass of rotating fluid, the form of an
oblate spheroid, the ellipticity of a meridian section being {1/231},
and the axes in the ratio 230 : 231. Geodetic measurements by the
Cassinis and other French astronomers pointed to a prolate form, but the
Newtonian figure was proved to be correct by the measurement of
meridional arcs in Peru and Lapland by the expeditions organized by the
French Academy of Sciences. More recent work points to an elliptical
equatorial section, thus making the earth pear-shaped. The position of
the longer axis is somewhat uncertain; it is certainly in Africa, Clarke
placing it in longitude 8° 15' W., and Schubert in longitude 41° 4' E.;
W.J. Sollas, arguing from terrestrial symmetry, has chosen the position
lat. 6° N., long. 28° E., i.e. between Clarke's and Schubert's
positions. For the lengths of the axes and the ellipticity of the Earth,
see EARTH, FIGURE OF THE.

2. _Mass and Density._--The earliest scientific investigation on the
density and mass of the Earth (the problem is really single if the
volume of the Earth be known) was made by Newton, who, mainly from
astronomical considerations, suggested the limiting densities 5 and 6;
it is remarkable that this prophetic guess should be realized, the mean
value from subsequent researches being about 5½, which gives for the
mass the value 6 × 10^21 tons. The density of the Earth has been
determined by several experimenters within recent years by methods
described in the article GRAVITATION; the most probable value is there
stated to be 5.527.

3. _Astronomical Relations._--The grandest achievements of astronomical
science are undoubtedly to be associated with the elucidation of the
complex motion of our planet. The notion that the Earth was fixed and
immovable at the centre of an immeasurable universe long possessed the
minds of men; and we find the illustrious Ptolemy accepting this view in
the 2nd century A.D., and rejecting the notion of a rotating Earth--a
theory which had been proposed as early as the 5th century B.C. by
Philolaus on philosophical grounds, and in the 3rd century B.C. by the
astronomer Aristarchus of Samos. He argued that if the Earth rotated
then points at the equator had the enormous velocity of about 1000 m.
per hour, and as a consequence there should be terrific gales from the
east; the fact that there were no such gales invalidated, in his
opinion, the theory. The Ptolemaic theory was unchallenged until 1543,
in which year the _De Revolutionibus orbium Celestium_ of Copernicus was
published. In this work it was shown that the common astronomical
phenomena could be more simply explained by regarding the Earth as
annually revolving about a fixed Sun, and daily rotating about itself. A
clean sweep was made of the geocentric epicyclic motions of the planets
which Ptolemy's theory demanded, and in place there was substituted a
procession of planets about the Sun at different distances. The
development of the Copernican theory--the corner-stone of modern
astronomy--by Johann Kepler and Sir Isaac Newton is treated in the
article ASTRONOMY: _History_; here we shall summarily discuss the
motions of our planet and its relation to the solar system.

The Earth has two principal motions--revolution about the Sun, rotation
about its axis; there are in addition a number of secular motions.

_Revolution._--The Earth revolves about the Sun in an elliptical orbit
having the Sun at one focus. The plane of the orbit is termed the
ecliptic; it is inclined to the Earth's equator at an angle termed the
obliquity, and the points of intersection of the equator and ecliptic
are termed the equinoctial points. The major axis of the ellipse is the
line of apsides; when the Earth is nearest the Sun it is said to be in
perihelion, when farthest it is in aphelion. The mean distance of the
Earth from the Sun is a most important astronomical constant, since it
is the unit of linear measurement; its value is about 93,000,000 m., and
the difference between the perihelion and aphelion distances is about
3,000,000 m. The eccentricity of the orbit is 0.016751. A tabular
comparison of the orbital constants of the Earth and the other planets
is given in the article PLANET. The period of revolution with regard to
the Sun, or, in other words, the time taken by the Sun apparently to
pass from one equinox to the same equinox, is the tropical or
equinoctial year; its length is 365 d. 5 hrs. 48 m. 46 secs. It is about
20 minutes shorter than the true or sidereal year, which is the time
taken for the Sun apparently to travel from one star to it again. The
difference in these two years is due to the secular variation termed
precession (see below). A third year is named the _anomalistic year_,
which is the time occupied in the passage from perihelion to perihelion;
it is a little longer than the sidereal.

_Rotation._--The Earth rotates about an axis terminating at the north
and south geographical poles, and perpendicular to the equator; the
period of rotation is termed the day (q.v.), of which several kinds are
distinguished according to the body or point of reference. The rotation
is performed from west to east; this daily rotation occasions the
_diurnal_ motion of the celestial sphere, the rising of the Sun and
stars in the east and their setting in the west, and also the phenomena
of day and night. The inclination of the axis to the ecliptic brings
about the presentation of places in different latitudes to the more
direct rays of the sun; this is revealed in the variation in the length
of daylight with the time of the year, and the phenomena of seasons.

Although the rotation of the Earth was an accepted fact soon after its
suggestion by Copernicus, an experimental proof was wanting until 1851,
when Foucault performed his celebrated pendulum experiment at the
Pantheon, Paris. A pendulum about 200 ft. long, composed of a flexible
wire carrying a heavy iron bob, was suspended so as to be free to
oscillate in any direction. The bob was provided with a style which
passed over a table strewn with fine sand, so that the style traced the
direction in which the bob was swinging. It was found that the
oscillating pendulum never retraced its path, but at each swing it was
apparently deviated to the right, and moreover the deviations in equal
times were themselves equal. This means that the floor of the Pantheon
was moving, and therefore the Earth was rotating. If the pendulum were
swung in the southern hemisphere, the deviation would be to the left; if
at the equator it would not deviate, while at the poles the plane of
oscillation would traverse a complete circle in 24 hours.

The rotation of the Earth appears to be perfectly uniform, comparisons
of the times of transits, eclipses, &c., point to a variation of less
than {1/100}th of a second since the time of Ptolemy. Theoretical
investigations on the phenomena of tidal friction point, however, to a
retardation, which may to some extent be diminished by the accelerations
occasioned by the shrinkage of the globe, and some other factors
difficult to evaluate (see TIDE).

We now proceed to the secular variations.

_Precession._--The axis of the earth does not preserve an invariable
direction in space, but in a certain time it describes a cone, in much
the same manner as the axis of a top spinning out of the vertical. The
equator, which preserves approximately the same inclination to the
ecliptic (there is a slight variation in the obliquity which we shall
mention later), must move so that its intersections with the ecliptic,
or equinoctial points, pass in a retrograde direction, i.e. opposite to
that of the Earth. This motion is termed the precession of the
equinoxes, and was observed by Hipparchus in the 2nd century B.C.;
Ptolemy corrected the catalogue of Hipparchus for precession by adding
2° 40' to the longitudes, the latitudes being unaltered by this motion,
which at the present time is 50.26" annually, the complete circuit being
made in about 26,000 years. Owing to precession the signs of the zodiac
are traversing paths through the constellations, or, in other
words, the constellations are continually shifting with regard to the
equinoctial points; at one time the vernal equinox Aries was in the
constellations of that name; it is now in Pisces, and will then pass
into Aquarius. The pole star, i.e. the star towards which the Earth's
axis points, is also shifting owing to precession; in about 2700 B.C.
the Chinese observed [alpha] Draconis as the pole star (at present
[alpha] Ursae minoris occupies this position and will do so until 3500);
in 13600 Vega ([alpha] Lyrae) the brightest star in the Northern
hemisphere, will be nearest.

Precession is the result of the Sun and the Moon's attraction on the
Earth not being a single force through its centre of gravity. If the
Earth were a homogeneous sphere the attractions would act through the
centre, and such forces would have no effect upon the rotation about the
centre of gravity, but the Earth being spheroidal the equatorial band
which stands up as it were beyond the surface of a sphere is more
strongly attracted, with the result that the axis undergoes a tilting.
The precession due to the Sun is termed the _solar precession_ and that
due to the Moon the _lunar precession_; the joint effect (two-thirds of
which is due to the Moon) is the _luni-solar_ precession. Solar
precession is greatest at the solstices and zero at the equinoxes; the
part of luni-solar precession due to the Moon varies with the position
of the Moon in its orbit. The obliquity is unchanged by precession (see
PRECESSION OF THE EQUINOXES).

_Nutation._--In treating precession we have stated that the axis of the
Earth traces a cone, and it follows that the pole describes a circle
(approximately) on the celestial sphere, about the pole of the ecliptic.
This is not quite true. Irregularities in the attracting forces which
occasion precession also cause a slight oscillation backwards and
forwards over the mean precessional path of the pole, the pole tracing a
wavy line or nodding. Both the Sun and Moon contribute to this effect.
Solar nutation depends upon the position of the Sun on the ecliptic; its
period is therefore 1 year, and in extent it is only 1.2"; lunar
nutation depends upon the position of the Moon's nodes; its period is
therefore about 18.6 years, the time of revolution of the nodes, and its
extent is 9.2". There is also given to the obliquity a small oscillation
to and fro. Nutation is one of the great discoveries of James Bradley
(1747).

_Planetary Precession._--So far we have regarded the ecliptic as
absolutely fixed, and treated precession as a real motion of the
equator. The ecliptic (q.v.), however, is itself subject to a motion,
due to the attractions of the planets on the Earth. This effect also
displaces the equinoctial points. Its annual value is 0.13". The term
General Precession in longitude is given to the displacement of the
intersection of the equator with the apparent ecliptic on the latter.
The standard value is 50.2453", which prevailed in 1850, and the value
at 1850 + t, i.e. the constant of precession, is 50.2453" + 0.0002225"
t. This value is also liable to a very small change. The nutation of the
obliquity at time 1850 + t is given by the formula 23° 27' 32.0" - 0.47"
t. Complete expressions for these functions are given in Newcomb's
_Spherical Astronomy_ (1908), and in the _Nautical Almanac_.

The variation of the _line of apsides_ is the name given to the motion
of the major axis of the Earth's orbit along the ecliptic. It is due to
the general influence of the planets, and the revolution is effected in
21,000 years.

The variation of the eccentricity denotes an oscillation of the form of
the Earth's orbit between a circle and ellipse. This followed the
mathematical researches of Lagrange and Leverrier. It was suggested by
Sir John Herschel in 1830 that this variation might occasion great
climatic changes, and James Croll developed the theory as affording a
solution of the glacial periods in geology (q.v.).

_Variation of Latitude._--Another secular motion of the Earth is due to
the fact that the axis of rotation is not rigidly fixed within it, but
its polar extremities wander in a circle of about 50 ft. diameter. This
oscillation brings about a variability in terrestrial latitudes, hence
the name. Euler showed mathematically that such an oscillation existed,
and, making certain assumptions as to the rigidity of the Earth, deduced
that its period was 305 days; S.C. Chandler, from 1890 onwards, deduced
from observations of the stars a period of 428 days; and Simon Newcomb
explained the deviation of these periods by pointing out that Euler's
assumption of a perfectly rigid Earth is not in accordance with fact.
For details of this intricate subject see the articles LATITUDE and
EARTH, FIGURE OF THE.

4. _Evolution and Age._--In its earliest history the mass now
consolidated as the Earth and Moon was part of a vast nebulous
aggregate, which in the course of time formed a central nucleus--our
Sun--which shed its outer layers in such a manner as to form the solar
system (see NEBULAR THEORY). The moon may have been formed from the
Earth in a similar manner, but the theory of tidal friction suggests the
elongation of the Earth along an equatorial axis to form a pear-shaped
figure, and that in the course of time the protuberance shot off to form
the Moon (see TIDE). The age of the Earth has been investigated from
several directions, as have also associated questions related to
climatic changes, internal temperature, orientation of the land and
water (permanence of oceans and continents), &c. These problems are
treated in the articles GEOLOGY and GEOGRAPHY.


FOOTNOTE:

  [1] Aristotle regarded the Earth as having an upper inhabited half
    and a lower uninhabited one, and the air on the lower half as tending
    to flow upwards through the Earth. The obstruction of this passage
    brought about an accumulation of air within the Earth, and the
    increased pressure may occasion oscillations of the surface, which
    may be so intense as to cause earthquakes.



EARTH, FIGURE OF THE. The determination of the figure of the earth is a
problem of the highest importance in astronomy, inasmuch as the diameter
of the earth is the unit to which all celestial distances must be
referred.


_Historical._

Reasoning from the uniform level appearance of the horizon, the
variations in altitude of the circumpolar stars as one travels towards
the north or south, the disappearance of a ship standing out to sea, and
perhaps other phenomena, the earliest astronomers regarded the earth as
a sphere, and they endeavoured to ascertain its dimensions. Aristotle
relates that the mathematicians had found the circumference to be
400,000 stadia (about 46,000 miles). But Eratosthenes (c. 250 B.C.)
appears to have been the first who entertained an accurate idea of the
principles on which the determination of the figure of the earth really
depends, and attempted to reduce them to practice. His results were very
inaccurate, but his method is the same as that which is followed at the
present day--depending, in fact, on the comparison of a line measured on
the earth's surface with the corresponding arc of the heavens. He
observed that at Syene in Upper Egypt, on the day of the summer
solstice, the sun was exactly vertical, whilst at Alexandria at the same
season of the year its zenith distance was 7° 12', or one-fiftieth of
the circumference of a circle. He assumed that these places were on the
same meridian; and, reckoning their distance apart as 5000 stadia, he
inferred that the circumference of the earth was 250,000 stadia (about
29,000 miles). A similar attempt was made by Posidonius, who adopted a
method which differed from that of Eratosthenes only in using a star
instead of the sun. He obtained 240,000 stadia (about 27,600 miles) for
the circumference. Ptolemy in his _Geography_ assigns the length of the
degree as 500 stadia.

The Arabs also investigated the question of the earth's magnitude. The
caliph Abdallah al Mamun (A.D. 814), having fixed on a spot in the
plains of Mesopotamia, despatched one company of astronomers northwards
and another southwards, measuring the journey by rods, until each found
the altitude of the pole to have changed one degree. But the result of
this measurement does not appear to have been very satisfactory. From
this time the subject seems to have attracted no attention until about
1500, when Jean Fernel (1497-1558), a Frenchman, measured a distance in
the direction of the meridian near Paris by counting the number of
revolutions of the wheel of a carriage. His astronomical observations
were made with a triangle used as a quadrant, and his resulting length
of a degree was very near the truth.

Willebrord Snell[1] substituted a chain of triangles for actual linear
measurement. He measured his base line on the frozen surface of the
meadows near Leiden, and measured the angles of his triangles, which lay
between Alkmaar and Bergen-op-Zoom, with a quadrant and semicircles. He
took the precaution of comparing his standard with that of the French,
so that his result was expressed in toises (the length of the toise is
about 6.39 English ft.). The work was recomputed and reobserved by P.
von Musschenbroek in 1729. In 1637 an Englishman, Richard Norwood,
published a determination of the figure of the earth in a volume
entitled _The Seaman's Practice, contayning a Fundamentall Probleme in
Navigation experimentally verified, namely, touching the Compasse of the
Earth and Sea and the quantity of a Degree in our English Measures_. He
observed on the 11th of June 1633 the sun's meridian altitude in London
as 62° 1', and on the 6th of June 1635, his meridian altitude in York as
59° 33'. He measured the distance between these places partly with a
chain and partly by pacing. By this means, through compensation of
errors, he arrived at 367,176 ft. for the degree--a very fair result.

The application of the telescope to angular instruments was the next
important step. Jean Picard was the first who in 1669, with the
telescope, using such precautions as the nature of the operation
requires, measured an arc of meridian. He measured with wooden rods a
base line of 5663 toises, and a second or base of verification of 3902
toises; his triangulation extended from Malvoisine, near Paris, to
Sourdon, near Amiens. The angles of the triangles were measured with a
quadrant furnished with a telescope having cross-wires. The difference
of latitude of the terminal stations was determined by observations made
with a sector on a star in Cassiopeia, giving 1° 22' 55" for the
amplitude. The terrestrial measurement gave 78,850 toises, whence he
inferred for the length of the degree 57,060 toises.

Hitherto geodetic observations had been confined to the determination of
the magnitude of the earth considered as a sphere, but a discovery made
by Jean Richer (d. 1696) turned the attention of mathematicians to its
deviation from a spherical form. This astronomer, having been sent by
the Academy of Sciences of Paris to the island of Cayenne, in South
America, for the purpose of investigating the amount of astronomical
refraction and other astronomical objects, observed that his clock,
which had been regulated at Paris to beat seconds, lost about two
minutes and a half daily at Cayenne, and that in order to bring it to
measure mean solar time it was necessary to shorten the pendulum by more
than a line (about {1/12}th of an in.). This fact, which was scarcely
credited till it had been confirmed by the subsequent observations of
Varin and Deshayes on the coasts of Africa and America, was first
explained in the third book of Newton's _Principia_, who showed that it
could only be referred to a diminution of gravity arising either from a
protuberance of the equatorial parts of the earth and consequent
increase of the distance from the centre, or from the counteracting
effect of the centrifugal force. About the same time (1673) appeared
Christian Huygens' _De Horologio Oscillatorio_, in which for the first
time were found correct notions on the subject of centrifugal force. It
does not, however, appear that they were applied to the theoretical
investigation of the figure of the earth before the publication of
Newton's _Principia_. In 1690 Huygens published his _De Causa
Gravitatis_, which contains an investigation of the figure of the earth
on the supposition that the attraction of every particle is towards the
centre.

Between 1684 and 1718 J. and D. Cassini, starting from Picard's base,
carried a triangulation northwards from Paris to Dunkirk and southwards
from Paris to Collioure. They measured a base of 7246 toises near
Perpignan, and a somewhat shorter base near Dunkirk; and from the
northern portion of the arc, which had an amplitude of 2° 12' 9",
obtained for the length of a degree 56,960 toises; while from the
southern portion, of which the amplitude was 6° 18' 57", they obtained
57,097 toises. The immediate inference from this was that, the degree
diminishing with increasing latitude, the earth must be a prolate
spheroid. This conclusion was totally opposed to the theoretical
investigations of Newton and Huygens, and accordingly the Academy of
Sciences of Paris determined to apply a decisive test by the measurement
of arcs at a great distance from each other--one in the neighbourhood of
the equator, the other in a high latitude. Thus arose the celebrated
expeditions of the French academicians. In May 1735 Louis Godin, Pierre
Bouguer and Charles Marie de la Condamine, under the auspices of Louis
XV., proceeded to Peru, where, assisted by two Spanish officers, after
ten years of laborious exertion, they measured an arc of 3° 7', the
northern end near the equator. The second party consisted of Pierre
Louis Moreau de Maupertuis, Alexis Claude Clairault, Charles Étienne
Louis Camus, Pierre Charles Lemonnier, and Reginaud Outhier, who reached
the Gulf of Bothnia in July 1736; they were in some respects more
fortunate than the first party, inasmuch as they completed the
measurement of an arc near the polar circle of 57' amplitude and
returned within sixteen months from the date of their departure.

The measurement of Bouguer and De la Condamine was executed with great
care, and on account of the locality, as well as the manner in which all
the details were conducted, it has always been regarded as a most
valuable determination. The southern limit was at Tarqui, the northern
at Cotchesqui. A base of 6272 toises was measured in the vicinity of
Quito, near the northern extremity of the arc, and a second base of 5260
toises near the southern extremity. The mountainous nature of the
country made the work very laborious, in some cases the difference of
heights of two neighbouring stations exceeding 1 mile; and they had much
trouble with their instruments, those with which they were to determine
the latitudes proving untrustworthy. But they succeeded by simultaneous
observations of the same star at the two extremities of the arc in
obtaining very fair results. The whole length of the arc amounted to
176,945 toises, while the difference of latitudes was 3° 7' 3". In
consequence of a misunderstanding that arose between De la Condamine and
Bouguer, their operations were conducted separately, and each wrote a
full account of the expedition. Bouguer's book was published in 1749;
that of De la Condamine in 1751. The toise used in this measure was
afterwards regarded as the standard toise, and is always referred to as
the _Toise of Peru_.

The party of Maupertuis, though their work was quickly despatched, had
also to contend with great difficulties. Not being able to make use of
the small islands in the Gulf of Bothnia for the trigonometrical
stations, they were forced to penetrate into the forests of Lapland,
commencing operations at Torneå, a city situated on the mainland near
the extremity of the gulf. From this, the southern extremity of their
arc, they carried a chain of triangles northward to the mountain Kittis,
which they selected as the northern terminus. The latitudes were
determined by observations with a sector (made by George Graham) of the
zenith distance of [alpha] and [delta] Draconis. The base line was
measured on the frozen surface of the river Torneå about the middle of
the arc; two parties measured it separately, and they differed by about
4 in. The result of the whole was that the difference of latitudes of
the terminal stations was 57' 29" .6, and the length of the arc 55,023
toises. In this expedition, as well as in that to Peru, observations
were made with a pendulum to determine the force of gravity; and these
observations coincided with the geodetic results in proving that the
earth was an oblate and not prolate spheroid.

In 1740 was published in the Paris _Mémoires_ an account, by Cassini de
Thury, of a remeasurement by himself and Nicolas Louis de Lacaille of
the meridian of Paris. With a view to determine more accurately the
variation of the degree along the meridian, they divided the distance
from Dunkirk to Collioure into four partial arcs of about two degrees
each, by observing the latitude at five stations. The results previously
obtained by J. and D. Cassini were not confirmed, but, on the contrary,
the length of the degree derived from these partial arcs showed on the
whole an increase with an increasing latitude. Cassini and Lacaille also
measured an arc of parallel across the mouth of the Rhone. The
difference of time of the extremities was determined by the observers at
either end noting the instant of a signal given by flashing gunpowder at
a point near the middle of the arc.

While at the Cape of Good Hope in 1752, engaged in various astronomical
observations, Lacaille measured an arc of meridian of 1° 13' 17", which
gave him for the length of the degree 57,037 toises--an unexpected
result, which has led to the remeasurement of the arc by Sir Thomas
Maclear (see GEODESY).

Passing over the measurements made between Rome and Rimini and on the
plains of Piedmont by the Jesuits Ruggiero Giuseppe Boscovich and
Giovanni Battista Beccaria, and also the arc measured with deal rods in
North America by Charles Mason and Jeremiah Dixon, we come to the
commencement of the English triangulation. In 1783, in consequence of a
representation from Cassini de Thury on the advantages that would accrue
from the geodetic connexion of Paris and Greenwich, General William Roy
was, with the king's approval, appointed by the Royal Society to conduct
the operations on the part of England, Count Cassini, Méchain and
Delambre being appointed on the French side. A precision previously
unknown was attained by the use of Ramsden's theodolite, which was the
first to make the spherical excess of triangles measurable. The wooden
rods with which the first base was measured were replaced by glass rods,
which were afterwards rejected for the steel chain of Ramsden. (For
further details see _Account of the Trigonometrical Survey of England
and Wales_.)

Shortly after this, the National Convention of France, having agreed to
remodel their system of weights and measures, chose for their unit of
length the ten-millionth part of the meridian quadrant. In order to
obtain this length precisely, the remeasurement of the French meridian
was resolved on, and deputed to J.B.J. Delambre and Pierre François
André Méchain. The details of this operation will be found in the _Base
du système métrique décimale_. The arc was subsequently extended by Jean
Baptiste Biot and Dominique François Jean Arago to the island of Iviza.
Operations for the connexion of England with the continent of Europe
were resumed in 1821 to 1823 by Henry Kater and Thomas Frederick Colby
on the English side, and F.J.D. Arago and Claude Louis Mathieu on the
French.

The publication in 1838 of Friedrich Wilhelm Bessel's _Gradmessung in
Ostpreussen_ marks an era in the science of geodesy. Here we find the
method of least squares applied to the calculation of a network of
triangles and the reduction of the observations generally. The
systematic manner in which all the observations were taken with the view
of securing final results of extreme accuracy is admirable. The
triangulation, which was a small one, extended about a degree and a half
along the shores of the Baltic in a N.N.E. direction. The angles were
observed with theodolites of 12 and 15 in. diameter, and the latitudes
determined by means of the transit instrument in the prime vertical--a
method much used in Germany. (The base apparatus is described in the
article GEODESY.)

The principal triangulation of Great Britain and Ireland, which was
commenced in 1783 under General Roy, for the more immediate purpose of
connecting the observatories of Greenwich and Paris, had been gradually
extended, under the successive direction of Colonel E. Williams, General
W. Mudge, General T.F. Colby, Colonel L.A. Hall, and Colonel Sir Henry
James; it was finished in 1851. The number of stations is about 250. At
32 of these the latitudes were determined with Ramsden's and Airy's
zenith sectors. The theodolites used for this work were, in addition to
the two great theodolites of Ramsden which were used by General Roy and
Captain Kater, a smaller theodolite of 18 in. diameter by the same
mechanician, and another of 24 in. diameter by Messrs Troughton and
Simms. Observations for determination of absolute azimuth were made with
those instruments at a large number of stations; the stars [alpha],
[delta], and [lambda] Ursae Minoris and 51 Cephei being those observed
always at the greatest azimuths. At six of these stations the probable
error of the result is under 0.4", at twelve under 0.5", at thirty-four
under 0.7": so that the absolute azimuth of the whole network is
determined with extreme accuracy. Of the seven base lines which have
been measured, five were by means of steel chains and two with Colby's
compensation bars (see GEODESY). The triangulation was computed by least
squares. The total number of equations of condition for the
triangulation is 920; if therefore the whole had been reduced in one
mass, as it should have been, the solution of an equation of 920 unknown
quantities would have occurred as a part of the work. To avoid this an
approximation was resorted to; the triangulation was divided into
twenty-one parts or figures; four of these, not adjacent, were first
adjusted by the method explained, and the corrections thus determined in
these figures carried into the equations of condition of the adjacent
figures. The average number of equations in a figure is 44; the largest
equation is one of 77 unknown quantities. The vertical limb of Airy's
zenith sector is read by four microscopes, and in the complete
observation of a star there are 10 micrometer readings and 12 level
readings. The instrument is portable; and a complete determination of
latitude, affected with the mean of the declination errors of two stars,
is effected by two micrometer readings and four level readings. The
observation consists in measuring with the telescope micrometer the
difference of zenith distances of two stars which cross the meridian,
one to the north and the other to the south of the observer at zenith
distances which differ by not much more than 10' or 15', the interval of
the times of transit being not less than one nor more than twenty
minutes. The advantages are that, with simplicity in the construction of
the instrument and facility in the manipulation, refraction is
eliminated (or nearly so, as the stars are generally selected within 25°
of the zenith), and there is no large divided circle. The telescope,
which is counterpoised on one side of the vertical axis, has a small
circle for finding, and there is also a small horizontal circle. This
instrument is universally used in American geodesy.

  The principal work containing the methods and results of these
  operations was published in 1858 with the title "Ordnance
  Trigonometrical Survey of Great Britain and Ireland. Account of the
  observations and calculations of the principal triangulation and of
  the figure, dimensions and mean specific gravity of the earth as
  derived therefrom. Drawn up by Captain Alexander Ross Clarke, R.E.,
  F.R.A.S., under the direction of Lieut.-Colonel H. James, R.E.,
  F.R.S., M.R.I.A., &c." A supplement appeared in 1862: "Extension of
  the Triangulation of the Ordnance Survey into France and Belgium, with
  the measurement of an arc of parallel in 52° N. from Valentia in
  Ireland to Mount Kemmel in Belgium. Published by ... Col. Sir Henry
  James."

Extensive operations for surveying India and determining the figure of
the earth were commenced in 1800. Colonel W. Lambton started the great
meridian arc at Punnae in latitude 8° 9', and, following generally the
methods of the English survey, he carried his triangulation as far north
as 20° 30'. The work was continued by Sir George (then Captain) Everest,
who carried it to the latitude of 29° 30'. Two admirable volumes by Sir
George Everest, published in 1830 and in 1847, give the details of this
undertaking. The survey was afterwards prosecuted by Colonel T.T.
Walker, R.E., who made valuable contributions to geodesy. The working
out of the Indian chains of triangle by the method of least squares
presents peculiar difficulties, but, enormous in extent as the work was,
it has been thoroughly carried out. The ten base lines on which the
survey depends were measured with Colby's compensation bars.

  The survey is detailed in eighteen volumes, published at Dehra Dun,
  and entitled _Account of the Operations of the Great Trigonometrical
  Survey of India_. Of these the first nine were published under the
  direction of Colonel Walker; and the remainder by Colonels Strahan and
  St G.C. Gore, Major S.G. Burrard and others. Vol. i., 1870, treats of
  the base lines; vol. ii., 1879, history and general descriptions of
  the principal triangulation and of its reduction; vol. v., 1879,
  pendulum operations (Captains T.P. Basevi and W.T. Heaviside); vols.
  xi., 1890, and xviii., 1906, latitudes; vols. ix., 1883, x., 1887,
  xv., 1893, longitudes; vol. xvii., 1901, the Indo-European
  longitude-arcs from Karachi to Greenwich. The other volumes contain
  the triangulations.

In 1860 Friedrich Georg Wilhelm Struve published his _Arc du méridien de
25° 20' entre le Danube et la Mer Glaciale mesuré depuis 1816 jusqu'en
1855_. The latitudes of the thirteen astronomical stations of this arc
were determined partly with vertical circles and partly by means of the
transit instrument in the prime vertical. The triangulation, a great
part of which, however, is a simple chain of triangles, is reduced by
the method of least squares, and the probable errors of the resulting
distances of parallels is given; the probable error of the whole arc in
length is ± 6.2 toises. Ten base lines were measured. The sum of the
lengths of the ten measured bases is 29,863 toises, so that the average
length of a base line is 19,100 ft. The azimuths were observed at
fourteen stations. In high latitudes the determination of the meridian
is a matter of great difficulty; nevertheless the azimuths at all the
northern stations were successfully determined,--the probable error of
the result at Fuglenaes being ± 0".53.

Before proceeding with the modern developments of geodetic measurements
and their application to the figure of the earth, we must discuss the
"mechanical theory," which is indispensable for a full understanding of
the subject.


_Mechanical Theory._

Newton, by applying his theory of gravitation, combined with the
so-called centrifugal force, to the earth, and assuming that an oblate
ellipsoid of rotation is a form of equilibrium for a homogeneous fluid
rotating with uniform angular velocity, obtained the ratio of the axes
229:230, and the law of variation of gravity on the surface. A few years
later Huygens published an investigation of the figure of the earth,
supposing the attraction of every particle to be towards the centre of
the earth, obtaining as a result that the proportion of the axes should
be 578 : 579. In 1740 Colin Maclaurin, in his _De causa physica fluxus
et refluxus maris_, demonstrated that the oblate ellipsoid of revolution
is a figure which satisfies the conditions of equilibrium in the case of
a revolving homogeneous fluid mass, whose particles attract one another
according to the law of the inverse square of the distance; he gave the
equation connecting the ellipticity with the proportion of the
centrifugal force at the equator to gravity, and determined the
attraction on a particle situated anywhere on the surface of such a
body. In 1743 Clairault published his _Théorie de la figure de la
terre_, which contains a remarkable theorem ("Clairault's Theorem"),
establishing a relation between the ellipticity of the earth and the
variation of gravity from the equator to the poles. Assuming that the
earth is composed of concentric ellipsoidal strata having a common axis
of rotation, each stratum homogeneous in itself, but the ellipticities
and densities of the successive strata varying according to any law, and
that the superficial stratum has the same form as if it were fluid, he
proved that

  g'- g       5
  ----- + e = -- m,
    g         2

where g, g' are the amounts of gravity at the equator and at the pole
respectively, e the ellipticity of the meridian (or "flattening"), and m
the ratio of the centrifugal force at the equator to g. He also proved
that the increase of gravity in proceeding from the equator to the poles
is as the square of the sine of the latitude. This, taken with the
former theorem, gives the means of determining the earth's ellipticity
from observation of the relative force of gravity at any two places.
P.S. Laplace, who devoted much attention to the subject, remarks on
Clairault's work that "the importance of all his results and the
elegance with which they are presented place this work amongst the most
beautiful of mathematical productions" (Isaac Todhunter's _History of
the Mathematical Theories of Attraction and the Figure of the Earth_,
vol. i. p. 229).

The problem of the figure of the earth treated as a question of
mechanics or hydrostatics is one of great difficulty, and it would be
quite impracticable but for the circumstance that the surface differs
but little from a sphere. In order to express the forces at any point of
the body arising from the attraction of its particles, the form of the
surface is required, but this form is the very one which it is the
object of the investigation to discover; hence the complexity of the
subject, and even with all the present resources of mathematicians only
a partial and imperfect solution can be obtained.

  We may here briefly indicate the line of reasoning by which some of
  the most important results may be obtained. If X, Y, Z be the
  components parallel to three rectangular axes of the forces acting on
  a particle of a fluid mass at the point x, y, z, then, p being the
  pressure there, and [rho] the density,

    dp = [rho](Xdx + Ydy + Zdz);

  and for equilibrium the necessary conditions are, that [rho](Xdx + Ydy
  + Zdz) be a complete differential, and at the free surface Xdx + Ydy +
  Zdz = 0. This equation implies that the resultant of the forces is
  normal to the surface at every point, and in a homogeneous fluid it is
  obviously the differential equation of all surfaces of equal pressure.
  If the fluid be heterogeneous then it is to be remarked that for
  forces of attraction according to the ordinary law of gravitation, if
  X, Y, Z be the components of the attraction of a mass whose potential
  is V, then

                       dV     dV     dV
    Xdx + Ydy + Zdz =  --dx + --dy + --dz,
                       dx     dy     dz

  which is a complete differential. And in the case of a fluid rotating
  with uniform velocity, in which the so-called centrifugal force enters
  as a force acting on each particle proportional to its distance from
  the axis of rotation, the corresponding part of Xdx + Ydy + Zdz is
  obviously a complete differential. Therefore for the forces with which
  we are now concerned Xdx + Ydy + Zdz = dU, where U is some function of
  x, y, z, and it is necessary for equilibrium that dp = [rho]dU be a
  complete differential; that is, [rho] must be a function of U or a
  function of p, and so also p a function of U. So that dU = 0 is the
  differential equation of surfaces of equal pressure and density.

  We may now show that a homogeneous fluid mass in the form of an oblate
  ellipsoid of revolution having a uniform velocity of rotation can be
  in equilibrium. It may be proved that the attraction of the ellipsoid
  x² + y² + z²(1 + [epsilon]²) = c²(1 + [epsilon]²); upon a particle P
  of its mass at x, y, z has for components

    X = -Ax, Y = -Ay, Z = -Cz,

  where

                     /1 + [epsilon]²                        1     \
    A = 2[pi]k²[rho]( ------------- tan^(-1) [epsilon] - --------  ),
                     \  [epsilon]³                      [epsilon]²/

                     /1 + [epsilon]²   1 + [epsilon]²                  \
    C = 4[pi]k²[rho]( -------------- - ------------- tan^(-1) [epsilon] ),
                     \  [epsilon]²      [epsilon]³                     /

  and k² the constant of attraction. Besides the attraction of the mass
  of the ellipsoid, the centrifugal force at P has for components +
  x[omega]², + y[omega]², 0; then the condition of fluid equilibrium is

    (A - [omega]²)xdx + (A - [omega]²)ydy + Czdz = 0,

  which by integration gives

    (A - [omega]²)(x² + y²) + Cz² = constant.

  This is the equation of an ellipsoid of rotation, and therefore the
  equilibrium is possible. The equation coincides with that of the
  surface of the fluid mass if we make

    A - [omega]² = C/(1 + [epsilon]²),

  which gives

      [omega]²     3 + [epsilon]²                           3
    ------------ = -------------- tan^(-1) [epsilon] - ---------- .
    2[pi]k²[rho]     [epsilon]³                        [epsilon]²

  In the case of the earth, which is nearly spherical, we obtain by
  expanding the expression for [omega]² in powers of [epsilon]²,
  rejecting the higher powers, and remarking that the ellipticity e =
  ½[epsilon]²,

    [omega]²/2[pi]k²[rho] = 4[epsilon]²/15 = 8e/15.

  Now if m be the ratio of the centrifugal force to the intensity of
  gravity at the equator, and a = c(1 + e), then

    m = a[omega]²,/(4/3)[pi]k²[rho]a, :. [omega]²/2[pi]k²[rho] = (2/3)m.

  In the case of the earth it is a matter of observation that m =
  1/289, hence the ellipticity

    e = 5m/4 = 1/231,

  so that the ratio of the axes on the supposition of a homogeneous
  fluid earth is 230:231, as stated by Newton.

  Now, to come to the case of a heterogeneous fluid, we shall assume
  that its surfaces of equal density are spheroids, concentric and
  having a common axis of rotation, and that the ellipticity of these
  surfaces varies from the centre to the outer surface, the density also
  varying. In other words, the body is composed of homogeneous
  spheroidal shells of variable density and ellipticity. On this
  supposition we shall express the attraction of the mass upon a
  particle in its interior, and then, taking into account the
  centrifugal force, form the equation expressing the condition of fluid
  equilibrium. The attraction of the homogeneous spheroid x² + y² + z²(1
  + 2e) = c²(1 + 2e), where e is the ellipticity (of which the square is
  neglected), on an internal particle, whose co-ordinates are x = f, y =
  0, z = h, has for its x and z components

    X' = -(4/3)[pi]k²[rho]f(1 - (2/5)e),
    Z' = -(4/3)[pi]k²[rho]h(1 + (4/5)e),

  the Y component being of course zero. Hence we infer that the
  attraction of a shell whose inner surface has an ellipticity e, and
  its outer surface an ellipticity e + de, the density being [rho], is
  expressed by

    dX' = (4/3)·(2/5)[pi]k²[rho]f de, dZ' = -(4/3)·(4/5)[pi]k²[rho]h de.

  To apply this to our heterogeneous spheroid; if we put c1 for the
  semiaxis of that surface of equal density on which is situated the
  attracted point P, and c0 for the semiaxis of the outer surface, the
  attraction of that portion of the body which is exterior to P, namely,
  of all the shells which enclose P, has for components
                    _                               _
          8        /c0     de           16         /c0     de
    X0 = --[pi]k²f | [rho] --dc, Z0 = - -- [pi]k²h | [rho] --dc,
         15       _/c1     dc           15        _/c1     dc

  both e and [rho] being functions of c. Again the attraction of a
  homogeneous spheroid of density [rho] on an _external_ point f, h has
  the components

    X" = -(4/3)[pi]k²[rho]fr^(-3) {c³(1 + 2e) - [lambda]ec^5},
    Z" = -(4/3)[pi]k²[rho]hr^(-3) {c³(1 + 2e) - [lambda]'ec^5},

  where [lambda] = (3/5)(4h² - f²)/r^4,
        [lambda]' = (3/5)(2h² - 3f²)/r^4, and r² = f² + h².

  Now e being considered a function of c, we can at once express the
  attraction of a shell (density [rho]) contained between the surface
  defined by c + dc, e + de and that defined by c, e upon an external
  point; the differentials with respect to c, viz. dX" dZ", must then
  be integrated with [rho] under the integral sign as being a function
  of c. The integration will extend from c = 0 to c = c1. Thus the
  components of the attraction of the heterogeneous spheroid upon a
  particle within its mass, whose co-ordinates are f, 0, h, are
                      _     _
          4          | 1   /c1
    X = - -- [pi]k²f | --  | [rho] d{c³(1 + 2e)}
          3          |_r³ _/0

                  _                    _        _
        [lambda] /c1               2  /c1        |
      - -------- | [rho] d(ec^5) - -- | [rho] de |,
           r³   _/0                5 _/0        _|
                      _     _
          4          | 1   /c1
    Z = - -- [pi]k²h | --  | [rho] d{c³(1 + 2e)}
          3          |_r³ _/0

                  _                    _        _
        [lambda]'/c1               4  /c1        |
      - -------- | [rho] d(ec^5) + -- | [rho] de |.
           r³   _/0                5 _/0        _|

  We take into account the rotation of the earth by adding the
  centrifugal force f[omega]² = F to X. Now, the surface of constant
  density upon which the point f, 0, h is situated gives (1 - 2e) fdf +
  hdh = 0; and the condition of equilibrium is that (X + F)df + Zdh = 0.
  Therefore,

    (X + F)h = Zf(1 - 2e),

  which, neglecting small quantities of the order e² and putting
  [omega]²t² = 4[pi]²k², gives
        _                            _                   _
    2e /c1                     6    /c1              6  /c0         3[pi]
    -- | [rho]d{c³(1 + 2e)} - ----  | [rho]d(ec^5) - -- | [rho]de = -----.
    r³_/0                     5r^5 _/0               5 _/c1           t²

  Here we must now put c for c1, c for r; and 1 + 2e under the first
  integral sign may be replaced by unity, since small quantities of the
  second order are neglected. Two differentiations lead us to the
  following very important differential equation (Clairault):

    d²e      2[rho]c²      de    /    2[rho]c      6 \
    --- + -------------- · -- + ( -------------- - -- ) e = 0.
    dc²   [int][rho]c²dc   dc    \[int][rho]c²dc   c²/

  When [rho] is expressed in terms of c, this equation can be
  integrated. We infer then that a rotating spheroid of very small
  ellipticity, composed of fluid homogeneous strata such as we have
  specified, will be in equilibrium; and when the law of the density is
  expressed, the law of the corresponding ellipticities will follow.

  If we put M for the mass of the spheroid, then
               _
        4[pi] /c                             c³   4[pi]²
    M = ----- | [rho]d{c³(1 + 2e)}; and m = --- · -----,
          3  _/0                             M      t²

  and putting c = c0 in the equation expressing the condition of
  equilibrium, we find
                             _
                4        6  /c
    M(2e - m) = -- [pi]·--- | [rho]d(ec^5).
                3       5c²_/0

  Making these substitutions in the expressions for the forces at the
  surface, and putting r/c = 1 + e - e(h/c)², we get
                       _                             _
                  Mk² |         3       /5      \  h² | f
    G cos [phi] = --- | 1 - e - -- m + ( - m - 2e) -- | --
                  ac  |_        2       \2      /  c²_| c
                       _                             _
                  Mk² |         3       /5      \  h² | h
    G sin [phi] = --- | 1 + e - -- m + ( - m - 2e) -- | --.
                  ac  |_        2       \2      /  c²_| c

  Here G is gravity in the latitude [phi], and a the radius of the
  equator. Since

    sec [phi] = (c/f){1 + e + (eh²/c²)},
             _                                 _
        Mk² |     3       /5      \             |
    G = --- | 1 - -- m + ( -- m - e) sin² [phi] |,
        ac  |_    2       \2      /            _|

  an expression which contains the theorems we have referred to as
  discovered by Clairault.

  The theory of the figure of the earth as a rotating ellipsoid has been
  especially investigated by Laplace in his _Mécanique celeste_. The
  principal English works are:--Sir George Airy, _Mathematical Tracts_,
  a lucid treatment without the use of Laplace's coefficients;
  Archdeacon Pratt's _Attractions and Figure of the Earth_; and
  O'Brien's _Mathematical Tracts_; in the last two Laplace's
  coefficients are used.

In 1845 Sir G.G. Stokes (_Camb. Trans._ viii.; see also _Camb. Dub.
Math. Journ._, 1849, iv.) proved that if the external form of the
sea--imagined to percolate the land by canals--be a spheroid with small
ellipticity, then the law of gravity is that which we have shown above;
his proof required no assumption as to the ellipticity of the internal
strata, or as to the past or present fluidity of the earth. This
investigation admits of being regarded conversely, viz. as determining
the elliptical form of the earth from measurements of gravity; if G, the
observed value of gravity in latitude [phi], be expressed in the form G
= g(1 + ß sin² [phi]), where g is the value at the equator and ß a
coefficient. In this investigation, the square and higher powers of the
ellipticity are neglected; the solution was completed by F.R. Helmert
with regard to the square of the ellipticity, who showed that a term
with sin² 2[phi] appeared (see Helmert, _Geodäsie_, ii. 83). For the
coefficient of this term, the gravity measurements give a small but not
sufficiently certain value; we therefore assume a value which agrees
best with the hypothesis of the fluid state of the entire earth; this
assumption is well supported, since even at a depth of only 50 km. the
pressure of the superincumbent crust is so great that rocks become
plastic, and behave approximately as fluids, and consequently the crust
of the earth floats, to some extent, on the interior (even though this
may not be fluid in the usual sense of the word). This is the geological
theory of "Isostasis" (cf. GEOLOGY); it agrees with the results of
measurements of gravity (_vide infra_), and was brought forward in the
middle of the 19th century by J.H. Pratt, who deduced it from
observations made in India.

The sin² 2[phi] term in the expression for G, and the corresponding
deviation of the meridian from an ellipse, have been analytically
established by Sir G.H. Darwin and E. Wiechert; earlier and less
complete investigations were made by Sir G.B. Airy and O. Callandreau.
In consequence of the sin² 2[phi] term, two parameters of the level
surfaces in the interior of the earth are to be determined; for this
purpose, Darwin develops two differential equations in the place of the
one by Clairault. By assuming Roche's law for the variation of the
density in the interior of the Earth, viz. [rho] = [rho]1 - k(c/c1)², k
being a coefficient, it is shown that in latitude 45°, the meridian is
depressed about 3¼ metres from the ellipse, and the coefficient of the
term sin² [phi] cos² [phi] (= ¼ sin² 2[phi]) is -0.0000295. According to
Wiechert the earth is composed of a kernel and a shell, the kernel being
composed of material, chiefly metallic iron, of density near 8.2, and
the shell, about 900 miles thick, of silicates, &c., of density about
3.2. On this assumption the depression in latitude 45° is 2¾ metres, and
the coefficient of sin² [phi] cos² [phi] is, in round numbers,
-0.0000280.[2] To this additional term in the formula for G, there
corresponds an extension of Clairault's formula for the calculation of
the flattening from ß with terms of the higher orders; this was first
accomplished by Helmert.

For a long time the assumption of an ellipsoid with three unequal axes
has been held possible for the figure of the earth, in consequence of an
important theorem due to K.G. Jacobi, who proved that for a homogeneous
fluid in rotation a spheroid is not the only form of equilibrium; an
ellipsoid rotating round its least axis may with certain proportions of
the axes and a certain time of revolution be a form of equilibrium.[3]
It has been objected to the figure of three unequal axes that it does
not satisfy, in the proportions of the axes, the conditions brought out
in Jacobi's theorem (c: a < 1/[root]2). Admitting this, it has to be
noted, on the other hand, that Jacobi's theorem contemplates a
homogeneous fluid, and this is certainly far from the actual condition
of our globe; indeed the irregular distribution of continents and oceans
suggests the possibility of a sensible divergence from a perfect surface
of revolution. We may, however, assume the ellipsoid with three unequal
axes to be an interpolation form. More plausible forms are little
adapted for computation.[4] Consequently we now generally take the
ellipsoid of rotation as a basis, especially so because measurements of
gravity have shown that the deviation from it is but trifling.


_Local Attraction._

In speaking of the figure of the earth, we mean the surface of the sea
imagined to percolate the continents by canals. That this surface
should turn out, after precise measurements, to be exactly an ellipsoid
of revolution is _a priori_ improbable. Although it may be highly
probable that originally the earth was a fluid mass, yet in the cooling
whereby the present crust has resulted, the actual solid surface has
been left most irregular in form. It is clear that these irregularities
of the visible surface must be accompanied by irregularities in the
mathematical figure of the earth, and when we consider the general
surface of our globe, its irregular distribution of mountain masses,
continents, with oceans and islands, we are prepared to admit that the
earth may not be precisely any surface of revolution. Nevertheless,
there must exist some spheroid which agrees very closely with the
mathematical figure of the earth, and has the same axis of rotation. We
must conceive this figure as exhibiting slight departures from the
spheroid, the two surfaces cutting one another in various lines; thus a
point of the surface is defined by its latitude, longitude, and its
height above the "spheroid of reference." Calling this height N, then of
the actual magnitude of this quantity we can generally have no
information, it only obtrudes itself on our notice by its variations. In
the vicinity of mountains it may change sign in the space of a few
miles; N being regarded as a function of the latitude and longitude, if
its differential coefficient with respect to the former be zero at a
certain point, the normals to the two surfaces then will lie in the
prime vertical; if the differential coefficient of N with respect to the
longitude be zero, the two normals will lie in the meridian; if both
coefficients are zero, the normals will coincide. The comparisons of
terrestrial measurements with the corresponding astronomical
observations have always been accompanied with discrepancies. Suppose A
and B to be two trigonometrical stations, and that at A there is a
disturbing force drawing the vertical through an angle [delta], then it
is evident that the apparent zenith of A will be really that of some
other place A', whose distance from A is r[delta], when r is the earth's
radius; and similarly if there be a disturbance at B of the amount
[delta]', the apparent zenith of B will be really that of some other
place B', whose distance from B is r[delta]'. Hence we have the
discrepancy that, while the geodetic measurements deal with the points A
and B, the astronomical observations belong to the points A', B'. Should
[delta], [delta]' be equal and parallel, the displacements AA', BB' will
be equal and parallel, and no discrepancy will appear. The
non-recognition of this circumstance often led to much perplexity in the
early history of geodesy. Suppose that, through the unknown variations
of N, the probable error of an observed latitude (that is, the angle
between the normal to the mathematical surface of the earth at the given
point and that of the corresponding point on the spheroid of reference)
be [epsilon], then if we compare two arcs of a degree each in mean
latitudes, and near each other, say about five degrees of latitude
apart, the probable error of the resulting value of the ellipticity will
be approximately ± 1/500[epsilon], [epsilon] being expressed in
seconds, so that if [epsilon] be so great as 2" the probable error of
the resulting ellipticity will be greater than the ellipticity itself.

It is necessary at times to calculate the attraction of a mountain, and
the consequent disturbance of the astronomical zenith, at any point
within its influence. The deflection of the plumb-line, caused by a
local attraction whose amount is k²A[delta], is measured by the ratio of
k²A[delta] to the force of gravity at the station. Expressed in seconds,
the deflection [Lambda] is

  [Lambda] = 12".447A[delta]/[rho],

where [rho] is the mean density of the earth, [delta] that of the
attracting mass, and A = [f]s^(-3)xdv, in which dv is a volume element
of the attracting mass within the distance s from the point of
deflection, and x the projection of s on the horizontal plane through
this point, the linear unit in expressing A being a mile. Suppose, for
instance, a table-land whose form is a rectangle of 12 miles by 8 miles,
having a height of 500 ft. and density half that of the earth; let the
observer be 2 miles distant from the middle point of the longer side.
The deflection then is 1".472; but at 1 mile it increases to 2".20.

At sixteen astronomical stations in the English survey the disturbance
of latitude due to the form of the ground has been computed, and the
following will give an idea of the results. At six stations the
deflection is under 2", at six others it is between 2" and 4", and at
four stations it exceeds 4". There is one very exceptional station on
the north coast of Banffshire, near the village of Portsoy, at which the
deflection amounts to 10", so that if that village were placed on a map
in a position to correspond with its astronomical latitude, it would be
1000 ft. out of position! There is the sea to the north and an
undulating country to the south, which, however, to a spectator at the
station does not suggest any great disturbance of gravity. A somewhat
rough estimate of the local attraction from external causes gives a
maximum limit of 5", therefore we have 5" which must arise from
unequal density in the underlying strata in the surrounding country. In
order to throw light on this remarkable phenomenon, the latitudes of a
number of stations between Nairn on the west, Fraserburgh on the east,
and the Grampians on the south, were observed, and the local deflections
determined. It is somewhat singular that the deflections diminish in all
directions, not _very_ regularly certainly, and most slowly in a
south-west direction, finally disappearing, and leaving the maximum at
the original station at Portsoy.

The method employed by Dr C. Hutton for computing the attraction of
masses of ground is so simple and effectual that it can hardly be
improved on. Let a horizontal plane pass through the given station; let
r, [theta] be the polar co-ordinates of any point in this plane, and r,
[theta], z, the co-ordinates of a particle of the attracting mass; and
let it be required to find the attraction of a portion of the mass
contained between the horizontal planes z = 0, z = h, the cylindrical
surfaces r = r1, r = r2, and the vertical planes [theta] = [theta]1,
[theta] = [theta]2. The component of the attraction at the station or
origin along the line [theta] = 0 is
             _    _          _
            /r2  /[theta]2  /h  r²cos [theta]
  k²[delta] |    |          |   ------------- dr d[theta] dz
           _/r1 _/[theta]1 _/0  (r²+z²)^(3/2)

    = k²[delta]h(sin[theta]2 - sin[theta]1) log{r2 + (r2² + h²)^(½)/r1 + (r1² + h²)^(½)}.

By taking r2 - r1, sufficiently small, and supposing h also small
compared with r1 + r2 (as it usually is), the attraction is

  k²[delta](r2 - r1)(sin [theta]2 - sin [theta]1)h/r,

where r= ½(r1 + r2). This form suggests the following procedure. Draw on
the contoured map a series of equidistant circles, concentric with the
station, intersected by radial lines so disposed that the sines of their
azimuths are in arithmetical progression. Then, having estimated from
the map the mean heights of the various compartments, the calculation is
obvious.

In mountainous countries, as near the Alps and in the Caucasus,
deflections have been observed to the amount of as much as 30", while
in the Himalayas deflections amounting to 60" were observed. On the
other hand, deflections have been observed in flat countries, such as
that noted by Professor K.G. Schweizer, who has shown that, at certain
stations in the vicinity of Moscow, within a distance of 16 miles the
plumb-line varies 16" in such a manner as to indicate a vast deficiency
of matter in the underlying strata; deflections of 10" were observed in
the level regions of north Germany.

Since the attraction of a mountain mass is expressed as a numerical
multiple of [delta] : [rho] the ratio of the density of the mountain to
that of the earth, if we have any independent means of ascertaining the
amount of the deflection, we have at once the ratio [rho]:[delta], and
thus we obtain the mean density of the earth, as, for instance, at
Schiehallion, and afterwards at Arthur's Seat. Experiments of this kind
for determining the mean density of the earth have been made in greater
numbers; but they are not free from objection (see GRAVITATION).

Let us now consider the perturbation attending a spherical subterranean
mass. A compact mass of great density at a small distance under the
surface of the earth will produce an elevation of the mathematical
surface which is expressed by the formula

  y = aµ((1 - 2u cos [theta] + u²)^(-½) - 1),

where a is the radius of the (spherical) earth, a(1 - u) the distance
of the disturbing mass below the surface, µ the ratio of the disturbing
mass to the mass of the earth, and a[theta] the distance of any point on
the surface from that point, say Q, which is vertically over the
disturbing mass. The maximum value of y is at Q, where it is y = aµu(1
-u). The deflection at the distance a[theta] is [Lambda] = µu
sin[theta](1 - 2u cos[theta] + u²)^(-3/2), or since [theta] is small,
putting h + u = 1, we have [Lambda] = µ[theta](h² + [theta]²)^(-3/2).
The maximum deflection takes place at a point whose distance from Q is
to the depth of the mass as 1:[root]2, and its amount is 2µ/3
[root](3h²). If, for instance, the disturbing mass were a sphere a mile
in diameter, the excess of its density above that of the surrounding
country being equal to half the density of the earth, and the depth of
its centre half a mile, the greatest deflection would be 5", and the
greatest value of y only two inches. Thus a large disturbance of gravity
may arise from an irregularity in the mathematical surface whose actual
magnitude, as regards height at least, is extremely small.

The effect of the disturbing mass µ on the vibrations of a pendulum
would be a maximum at Q; if v be the number of seconds of time gained
per diem by the pendulum at Q, and [sigma] the number of seconds of
angle in the maximum deflection, then it may be shown that v/[sigma] =
[pi][root]3/10.

The great Indian survey, and the attendant measurements of the degree of
latitude, gave occasion to elaborate investigations of the deflection of
the plumb-line in the neighbourhood of the high plateaus and mountain
chains of Central Asia. Archdeacon Pratt (_Phil. Trans._, 1855 and
1857), in instituting these investigations, took into consideration the
influence of the apparent diminution of the mass of the earth's crust
occasioned by the neighbouring ocean-basins; he concluded that the
accumulated masses of mountain chains, &c., corresponded to subterranean
mass diminutions, so that over any level surface in a fixed depth
(perhaps 100 miles or more) the masses of prisms of equal section are
equal. This is supported by the gravity measurements at Moré in the
Himalayas at a height of 4696 metres, which showed no deflection due to
the mountain chain (_Phil. Trans._, 1871); more recently, H.A. Faye
(_Compt. rend._, 1880) arrived at the same conclusion for the entire
continent.

This compensation, however, must only be regarded as a general
principle; in certain cases, the compensating masses show marked
horizontal displacements. Further investigations, especially of gravity
measurements, will undoubtedly establish other important facts. Colonel
S.G. Burrard has recently recalculated, with the aid of more exact data,
certain Indian deviations of the plumb-line, and has established that in
the region south of the Himalayas (lat. 24°) there is a subterranean
perturbing mass. The extent of the compensation of the high mountain
chains is difficult to recognize from the latitude observations, since
the same effect may result from different causes; on the other hand,
observations of geographical longitude have established a strong
compensation.[5]


_Meridian Arcs._

The astronomical stations for the measurement of the degree of latitude
will generally lie not exactly on the same meridian; and it is therefore
necessary to calculate the arcs of meridian M which lie between the
latitude of neighbouring stations. If S be the geodetic line calculated
from the triangulation with the astronomically determined azimuths
[alpha]1 and [alpha]2, then
                             _                                _
            cos [alpha]     |      1    S²                     |
  M = S ------------------- | 1 + -- -------- sin² [alpha] ... |,
        cos ½[Delta][alpha] |_    12 [alpha]²                 _|

in which 2[alpha] = [alpha]1 + [alpha]2 - 180°, [Delta][alpha] =
[alpha]2 - [alpha]1 - 180°.

The length of the arc of meridian between the latitudes [phi]1 and
[phi]2 is

       _[phi]2                 _[phi]2
      /                       /         (1 - e²)d[phi]
  M = | [rho]d[phi] = [alpha] |     -----------------------
     _/                      _/     (1 - e²sin²[phi])^(3/2)
      [phi]1                  [phi]1

where a²e² = a² - b²; instead of using the eccentricity e, put the ratio
of the axes b:a = 1 - n:1 + n, then

       _[phi]2
      /         b(1 + n)(1 - n²)d[phi]
  M = |     ------------------------------.
     _/     (1 + 2n cos 2[phi] + n²)^(3/2)
      [phi]1

This, after integration, gives

         /        5      5 \              /            21 \
  M/b = ( 1 + n + -n²  + -n³) [alpha]0 - ( 3n +  3n² + --n³) [alpha]1
         \        4      4 /              \             8 /

       /15     15 \              /35  \
    + ( --n² + --n³) [alpha]2 - ( --n³ ) [alpha]3,
       \ 8      8 /              \24  /

where

  [alpha]0 = [phi]2 -  [phi]1
  [alpha]1 = sin ([phi]2 - [phi]1) cos ([phi]2 + [phi]1)
  [alpha]2 = sin 2([phi]2 - [phi]1) cos 2([phi]2 + [phi]1)
  [alpha]3 = sin 3([phi]2 - [phi]1) cos 3([phi]2 + [phi]1).

The part of M which depends on n³ is very small; in fact, if we
calculate it for one of the longest arcs measured, the Russian arc, it
amounts to only an inch and a half, therefore we omit this term, and put
for M/b the value

   /       5  \                                    /15 \
  (l + n + --n²) [alpha]0 - (3n + 3n²) [alpha]1 + ( --n²) [alpha]2.
   \       4  /                                    \ 8 /

Now, if we suppose the observed latitudes to be affected with errors,
and that the true latitudes are [phi]1 + x1, [phi]2 + x2; and if further
we suppose that n1 + dn is the true value of a - b:a + b, and that n1
itself is merely a very approximate numerical value, we get, on making
these substitutions and neglecting the influence of the corrections x on
the _position_ of the arc in latitude, i.e. on [phi]1 + [phi]2,

         /           5   \             /        \             /15  \
  M/b = ( 1 + n    + --n1²)[alpha]0 - (3n1 + 3n1²)[alpha]1 + ( --n1²)[alpha]2
         \           4   /             \        /             \8   /
       _                                             _
      |  /    5    \       /       \       /15   \    |
    + | ( 1 + -- n1 )a0 - ( 3 + 6n1 )a1 + ( -- n1 )a2 | dn
      |_ \    2    /       \       /       \4    /   _|
       _               _
      |             da1 |
    + | 1 + n1 - 3n --- | da0;
      |_            da0_|

here da0 = x2 - x1; and as b is only known approximately, put b = b1(1 +
u); then we get, after dividing through by the coefficient of da0, which
is = 1 + n1 - 3n1 cos([phi]2 - [phi]1) cos([phi]2 + [phi]1), an equation
of the form x2 = x1 + h + fu + gv, where for convenience we put v for
dn.

Now in every measured arc there are not only the extreme stations
determined in latitude, but also a number of intermediate stations so
that if there be i + 1 stations there will be i equations

  x2 = x1 + f1u + g1v + h1
  x3 = x1 + f2u + g2v + h2
   :    :                :
   :    :                :
  x_i = x1 + f_iu + g_iv + h_i

In combining a number of different arcs of meridian, with the view of
determining the figure of the earth, each arc will supply a number of
equations in u and v and the corrections to its observed latitudes.
Then, according to the method of least squares, those values of u and v
are the most probable which render the sum of the squares of _all_ the
errors x a minimum. The corrections x which are here applied arise not
from errors of observation only. The mere uncertainty of a latitude, as
determined with modern instruments, does not exceed a very small
fraction of a second as far as errors of observation go, but no accuracy
in observing will remove the error that may arise from local attraction.
This, as we have seen, may amount to some seconds, so that the
corrections x to the observed latitudes are attributable to local
attraction. Archdeacon Pratt objected to this mode of applying least
squares first used by Bessel; but Bessel was right, and the objection is
groundless. Bessel found, in 1841, from ten meridian arcs with a total
amplitude of 50°.6:

  a = 3272077 toises = 6377397 metres.
  e (ellipticity) = (a - b)/a = 1/299.15 (prob. error ± 3.2).

The probable error in the length of the earth's quadrant is ± 336 m.

We now give a series of some meridian-arcs measurements, which were
utilized in 1866 by A.R. Clarke in the _Comparisons of the Standards of
Length_, pp. 280-287; details of the calculations are given by the same
author in his _Geodesy_ (1880), pp. 311 et seq.

The data of the French arc from Formentera to Dunkirk are--

  Stations.        Astronomical       Distance of
                     Latitudes.        Parallels.
                    °   '    "             Ft.
  Formentera       38  39  53.17            ..
  Mountjouy        41  21  44.96         982671.04
  Barcelona        41  22  47.90         988701.92
  Carcassonne      43  12  54.30        1657287.93
  Pantheon         48  50  47.98        3710827.13
  Dunkirk          51   2   8.41        4509790.84

The distance of the parallels of Dunkirk and Greenwich, deduced from the
extension of the triangulation of England into France, in 1862, is
161407.3 ft., which is 3.9 ft. greater than that obtained from Captain
Kater's triangulation, and 3.2 ft. less than the distance calculated by
Delambre from General Roy's triangulation. The following table shows the
data of the English arc with the distances in standard feet from
Formentera.

                    °   '    "             Ft.
  Formentera            ..                  ..
  Greenwich        51  28  38.30         4671198.3
  Arbury           52  13  26.59         4943837.6
  Clifton          53  27  29.50         5394063.4
  Kellie Law       56  14  53.60         6413221.7
  Stirling         57  27  49.12         6857323.3
  Saxavord         60  49  37.21         8086820.7

The latitude assigned in this table to Saxavord is not the directly
observed latitude, which is 60° 49' 38.58", for there are here a
cluster of three points, whose latitudes are astronomically determined;
and if we transfer, by means of the geodesic connexion, the latitude of
Gerth of Scaw to Saxavord, we get 60° 49' 36.59"; and if we similarly
transfer the latitude of Balta, we get 60° 49' 36.46". The mean of
these three is that entered in the above table.

For the Indian arc in long. 77° 40' we have the following data:--

                    °   '     "             Ft.
  Punnea            8   9   31.132          ..
  Putchapolliam    10  59   42.276       1029174.9
  Dodagunta        12  59   52.165       1756562.0
  Namthabad        15   5   53.562       2518376.3
  Daumergida       18   3   15.292       3591788.4
  Takalkhera       21   5   51.532       4697329.5
  Kalianpur        24   7   11.262       5794695.7
  Kaliana          29  30   48.322       7755835.9

The data of the Russian arc (long. 26° 40') taken from Struve's work are
as below:--

                    °   '    "              Ft.
  Staro Nekrasovsk 45  20   2.94            ..
  Vodu-Luy         47   1  24.98         616529.81
  Suprunkovzy      48  45   3.04        1246762.17
  Kremenets        50   5  49.95        1737551.48
  Byelin           52   2  42.16        2448745.17
  Nemesh           54  39   4.16        3400312.63
  Jacobstadt       56  30   4.97        4076412.28
  Dorpat           58  22  47.56        4762421.43
  Hogland          60   5   9.84        5386135.39
  Kilpi-maki       62  38   5.25        6317905.67
  Torneå           65  49  44.57        7486789.97
  Stuor-oivi       68  40  58.40        8530517.90
  Fuglenaes        70  40  11.23        9257921.06

From the are measured in Cape Colony by Sir Thomas Maclear in long. 18°
30', we have

                        °   '     "         Ft.
  North End            29  44   17.66       ..
  Heerenlogement Berg  31  58    9.11     811507.7
  Royal Observatory    33  56    3.20    1526386.8
  Zwart Kop            34  13   32.13    1632583.3
  Cape Point           34  21    6.26    1678375.7

And, finally, for the Peruvian arc, in long. 281° 0',

                   °   '     "              Ft.
  Tarqui           3   4   32.068           ..
  Cotchesqui       0   2   31.387        1131036.3

Having now stated the data of the problem, we may seek that oblate
ellipsoid (spheroid) which best represents the observations. Whatever
the real figure may be, it is certain that if we suppose it an ellipsoid
with three unequal axes, the arithmetical process will bring out an
ellipsoid, which will agree better with all the observed latitudes than
any spheroid would, therefore we do not _prove_ that it is an ellipsoid;
to prove this, arcs of longitude would be required. The result for the
spheroid may be expressed thus:--

  a = 20926062 ft. = 6378206.4 metres.
  b = 20855121 ft. = 6356583.8 metres.
  b : a = 293.98 : 294.98.

As might be expected, the sum of the squares of the 40 latitude
corrections, viz. 153.99, is greater in this figure than in that of
three axes, where it amounts to 138.30. For this case, in the Indian arc
the largest corrections are at Dodagunta, + 3.87", and at Kalianpur, -
3.68". In the Russian arc the largest corrections are + 3.76", at
Torneå, and - 3.31", at Staro Nekrasovsk. Of the whole 40 corrections,
16 are under 1.0", 10 between 1.0" and 2.0", 10 between 2.0" and
3.0", and 4 over 3.0". The probable error of an observed latitude is ±
1.42"; for the spheroidal it would be very slightly larger. This
quantity may be taken therefore as approximately the probable amount of
local deflection.

If [rho] be the radius of curvature of the meridian in latitude [phi],
[rho]' that perpendicular to the meridian, D the length of a degree of
the meridian, D' the length of a degree of longitude, r the radius drawn
from the centre of the earth, V the angle of the vertical with the
radius-vector, then

             Ft.
     [rho]  = 20890606.6          - 106411.5 cos 2[phi] + 225.8 cos 4[phi]
     [rho]' = 20961607.3          -  35590.9 cos 2[phi] + 45.2 cos 4[phi]
     D      = 364609.87           -  1857.14 cos 2[phi] + 3.94 cos 4[phi]
     D'     = 365538.48 cos [phi] -   310.17 cos 3[phi] + 0.39 cos 5[phi]
  Log r/a   = 9.9992645           + .0007374 cos 2[phi] - .0000019 cos 4[phi]
     V      = 700.44" sin 2[phi] - 1.19" sin 4[phi].

A.R. Clarke has recalculated the elements of the ellipsoid of the earth;
his values, derived in 1880, in which he utilized the measurements of
parallel arcs in India, are particularly in practice. These values
are:--

  a = 20926202 ft. = 6378249 metres,
  b = 20854895 ft. = 6356515 metres,
  b : a = 292.465 : 293.465.

  The calculation of the elements of the ellipsoid of rotation from
  measurements of the curvature of arcs in any given azimuth by means of
  geographical longitudes, latitudes and azimuths is indicated in the
  article GEODESY; reference may be made to _Principal Triangulation_,
  Helmert's _Geodasie_, and the publications of the Kgl. Preuss. Geod.
  Inst.:--_Lotabweichungen_ (1886), and _Die europ. Längengradmessung in
  52° Br._ (1893). For the calculation of an ellipsoid with three
  unequal axes see _Comparison of Standards_, preface; and for
  non-elliptical meridians, _Principal Triangulation_, p. 733.


_Gravitation-Measurements._

According to Clairault's theorem (see above) the ellipticity e of the
mathematical surface of the earth is equal to the difference (5/2)m -ß,
where m is the ratio of the centrifugal force at the equator to gravity
at the equator, and ß is derived from the formula G = g(1 + ß
sin²[phi]). Since the beginning of the 19th century many efforts have
been made to determine the constants of this formula, and numerous
expeditions undertaken to investigate the intensity of gravity in
different latitudes. If m be known, it is only necessary to determine ß
for the evaluation of e; consequently it is unnecessary to determine G
absolutely, for the relative values of G at two known latitudes suffice.
Such relative measurements are easier and more exact than absolute ones.
In some cases the ordinary thread pendulum, i.e. a spherical bob
suspended by a wire, has been employed; but more often a rigid metal
rod, bearing a weight and a knife-edge on which it may oscillate, has
been adopted. The main point is the constancy of the pendulum. From the
formula for the time of oscillation of the mathematically ideal
pendulum, t = 2 [pi] [root](l/G), l being the length, it follows that
for two points G1/G2 = t2²/t1².

In 1808 J.B. Biot commenced his pendulum observations at several
stations in western Europe; and in 1817-1825 Captain Louis de Freycinet
and L.I. Duperrey prosecuted similar observations far into the southern
hemisphere. Captain Henry Kater confined himself to British stations
(1818-1819); Captain E. Sabine, from 1819 to 1829, observed similarly,
with Kater's pendulum, at seventeen stations ranging from the West
Indies to Greenland and Spitsbergen; and in 1824-1831, Captain Henry
Foster (who met his death by drowning in Central America) experimented
at sixteen stations; his observations were completed by Francis Baily in
London. Of other workers in this field mention may be made of F.B. Lütke
(1826-1829), a Russian rear-admiral, and Captains J.B. Basevi and W.T.
Heaviside, who observed during 1865 to 1873 at Kew and at 29 Indian
stations, particularly at Moré in the Himalayas at a height of 4696
metres. Of the earlier absolute determinations we may mention those of
Biot, Kater, and Bessel at Paris, London and Königsberg respectively.
The measurements were particularly difficult by reason of the length of
the pendulums employed, these generally being second-pendulums over 1
metre long. In about 1880, Colonel Robert von Sterneck of Austria
introduced the half-second pendulum, which permitted far quicker and
more accurate work. The use of these pendulums spread in all countries,
and the number of gravity stations consequently increased: in 1880 there
were about 120, in 1900 there were about 1600, of which the greater
number were in Europe. Sir E. Sabine[6] calculated the ellipticity to be
1/288.5, a value shown to be too high by Helmert, who in 1884, with the
aid of 120 stations, gave the value 1/299.26,[7] and in 1901, with about
1400 stations, derived the value 1/298.3.[8] The reason for the
excessive estimate of Sabine is that he did not take into account the
systematic difference between the values of G for continents and
islands; it was found that in consequence of the constitution of the
earth's crust (Pratt) G is greater on small islands of the ocean than
on continents by an amount which may approach to 0.3 cm. Moreover,
stations in the neighbourhood of coasts shelving to deep seas have a
surplus, but a little smaller. Consequently, Helmert conducted his
calculations of 1901 for continents and coasts separately, and obtained
G for the coasts 0.036 cm. greater than for the continents, while the
value of ß remained the same. The mean value, reduced to continents, is

  G = 978.03(1 + 0.005302 sin²[phi] - 0.000007 sin² 2[phi])cm/sec².

The small term involving sin² 2[phi] could not be calculated with
sufficient exactness from the observations, and is therefore taken from
the theoretical views of Sir G.H. Darwin and E. Wiechert. For the
constant g = 978.03 cm. another correction has been suggested (1906) by
the absolute determinations made by F. Kühnen and Ph. Furtwängler at
Potsdam.[9]

  A report on the pendulum measurements of the 19th century has been
  given by Helmert in the _Comptes rendus des séances de la 13^e
  conférence générale de l'Association Géod. Internationale à Paris_
  (1900), ii. 139-385.

A difficulty presents itself in the case of the application of
measurements of gravity to the determination of the figure of the earth
by reason of the extrusion or standing out of the land-masses
(continents, &c.) above the sea-level. The potential of gravity has a
different mathematical expression outside the masses than inside. The
difficulty is removed by assuming (with Sir G.G. Stokes) the vertical
condensation of the masses on the sea-level, without its form being
considerably altered (scarcely 1 metre radially). Further, the value of
gravity (g) measured at the height H is corrected to sea-level by +
2gH/R, where R is the radius of the earth. Another correction, due to P.
Bouguer, is -(3/2)g[delta]H/[rho]R, where [delta] is the density of the
strata of height H, and [rho] the mean density of the earth. These two
corrections are represented in "Bouguer's Rule": g_H = g_s(1 - 2H/R +
3[delta]H/2[rho]R), where g_H is the gravity at height H, and g_s the
value at sea-level. This is supposed to take into account the attraction
of the elevated strata or plateau; but, from the analytical method, this
is not correct; it is also disadvantageous since, in general, the
land-masses are compensated subterraneously, by reason of the isostasis
of the earth's crust.

In 1849 Stokes showed that the normal elevations N of the geoid towards
the ellipsoid are calculable from the deviations [Delta]g of the
acceleration of gravity, i.e. the differences between the observed g and
the value calculated from the normal G formula. The method assumes that
gravity is measured on the earth's surface at a sufficient number of
points, and that it is conformably reduced. In order to secure the
convergence of the expansions in spherical harmonics, it is necessary to
assume all masses outside a surface parallel to the surface of the sea
at a depth of 21 km. (= R × ellipticity) to be condensed on this surface
(Helmert, _Geod._ ii. 172). In addition to the reduction with 2gH/R,
there still result small reductions with mountain chains and coasts, and
somewhat larger ones for islands. The sea-surface generally varies but
very little by this condensation. The elevation (N) of the geoid is then
equal to
         _
        /[pi]
  N = R |  FG^(-1) [Delta]g_[psi] d[psi],
       _/

where [psi] is the spherical distance from the point N, and
[Delta]g_[psi] denotes the mean value of [Delta]g for all points in the
same distance [psi] around; F is a function of [psi], and has the
following values:--

  +-------+-------+
  | [Psi]=|   F=  |
  +-------+-------+
  |    0° |  1    |
  |   10° |  1.22 |
  |   20° |  0.94 |
  |   30° |  0.47 |
  |   40° | -0.06 |
  |   50° | -0.54 |
  |   60° | -0.90 |
  |   70° | -1.08 |
  |   80° | -1.08 |
  |   90° | -0.91 |
  |  100° | -0.62 |
  |  110° | -0.27 |
  |  120° | +0.08 |
  |  130° |  0.36 |
  |  140° |  0.53 |
  |  150° |  0.56 |
  |  160° |  0.46 |
  |  170° |  0.26 |
  |  180° |  0    |
  +-------+-------+

H. Poincaré (_Bull. Astr._, 1901, p. 5) has exhibited N by means of
Lamé's functions; in this case the condensation is effected on an
ellipsoidal surface, which approximates to the geoid. This condensation
is, in practice, the same as to the geoid itself.

If we imagine the outer land-masses to be condensed on the sea-level,
and the inner masses (which, together with the outer masses, causes the
deviation of the geoid from the ellipsoid) to be compensated in the
sea-level by a disturbing stratum (which, according to Gauss, is
possible), and if these masses of both kinds correspond at the point N
to a stratum of thickness D and density [delta], then, according to
Helmert (_Geod._ ii. 260) we have approximately

             3  g   /[delta]D    \
  [Delta]g = -- -- ( -------- - N ).
             2  R   \  [rho]     /

Since N slowly varies empirically, it follows that in restricted regions
(of a few 100 km. in diameter) [Delta]g is a measure of the variation of
D. By applying the reduction of Bouguer to g, D is diminished by H and
only gives the thickness of the ideal disturbing mass which corresponds
to the perturbations due to subterranean masses. [Delta]g has positive
values on coasts, small islands, and high and medium mountain chains,
and occasionally in plains; while in valleys and at the foot of mountain
ranges it is negative (up to 0.2 cm.). We conclude from this that the
masses of smaller density existing under high mountain chains lie not
only vertically underneath but also spread out sideways.


_The European Arc of Parallel in 52° Lat._

Many measurements of degrees of longitudes along central parallels in
Europe were projected and partly carried out as early as the first half
of the 19th century; these, however, only became of importance after the
introduction of the electric telegraph, through which calculations of
astronomical longitudes obtained a much higher degree of accuracy. Of
the greatest moment is the measurement near the parallel of 52° lat.,
which extended from Valentia in Ireland to Orsk in the southern Ural
mountains over 69° long, (about 6750 km.). F.G.W. Struve, who is to be
regarded as the father of the Russo-Scandinavian latitude-degree
measurements, was the originator of this investigation. Having made the
requisite arrangements with the governments in 1857, he transferred
them to his son Otto, who, in 1860, secured the co-operation of England.
A new connexion of England with the continent, via the English Channel,
was accomplished in the next two years; whereas the requisite
triangulations in Prussia and Russia extended over several decennaries.
The number of longitude stations originally arranged for was 15; and the
determinations of the differences in longitude were uniformly commenced
by the Russian observers E.I. von Forsch, J.I. Zylinski, B. Tiele and
others; Feaghmain (Valentia) being reserved for English observers. With
the concluding calculation of these operations, newer determinations of
differences of longitudes were also applicable, by which the number of
stations was brought up to 29. Since local deflections of the plumb-line
were suspected at Feaghmain, the most westerly station, the longitude
(with respect to Greenwich) of the trigonometrical station Killorglin at
the head of Dingle Bay was shortly afterwards determined.

  The results (1891-1894) are given in volumes xlvii. and l. of the
  memoirs (Zapiski) of the military topographical division of the
  Russian general staff, volume li. contains a reconnexion of Orsk. The
  observations made west of Warsaw are detailed in the _Die europ.
  Längengradmessung in 52° Br._, i. and ii., 1893, 1896, published by
  the Kgl. Preuss. Geod. Inst.

The following figures are quoted from Helmert's report "Die Grösse der
Erde" (_Sitzb. d. Berl. Akad. d. Wiss._, 1906, p. 535):--

  _Easterly Deviation of the Astronomical Zenith_.

    Name.                   Longitude.
                          °    '      "
  Feaghmain             -10   21    -3.3
  Killorglin            - 9   47    +2.8
  Haverfordwest         - 4   58    +1.6
  Greenwich               0    0    +1.5
  Rosendaël-Nieuport    + 2   35    -1.7
  Bonn                  + 7    6    -4.4
  Göttingen             + 9   57    -2.4
  Brocken               +10   37    +2.3
  Leipzig               +12   23    +2.7
  Rauenberg-Berlin      +13   23    +1.7
  Grossenhain           +13   33    -2.9
  Schneekoppe           +15   45    +0.1
  Springberg            +16   37    +0.8
  Breslau-Rosenthal     +17    2    +3.5
  Trockenberg           +18   53    -0.5
  Schönsee              +18   54    -2.9
  Mirov                 +19   18    +2.2
  Warsaw                +21    2    +1.9
  Grodno                +23   50    -2.8
  Bobruisk              +29   14    +0.5
  Orel                  +36    4    +4.4
  Lipetsk               +39   36    +0.2
  Saratov               +46    3    +6.4
  Samara                +50    5    -2.6
  Orenburg              +55    7    +1.7
  Orsk                  +58   34    -8.0

These deviations of the plumb-line correspond to an ellipsoid having an
equatorial radius (a) of nearly 6,378,000 metres (prob. error ± 70
metres) and an ellipticity 1/299.15. The latter was taken for granted;
it is nearly equal to the result from the gravity-measurements; the
value for a then gives [Sigma][eta]² a minimum (nearly). The
astronomical values of the geographical longitudes (with regard to
Greenwich) are assumed, according to the compensation of longitude
differences carried out by van de Sande Bakhuyzen (_Comp. rend, des
séances de la commission permanente de l'Association Géod.
Internationale à Genève, 1893, annexe A.I._). Recent determinations
(Albrecht, _Astr. Nach._, 3993/4) have introduced only small alterations
in the deviations, a being slightly increased.

Of considerable importance in the investigation of the great arc was
the representation of the linear lengths found in different countries,
in terms of the same unit. The necessity for this had previously
occurred in the computation of the figure of the earth from
latitude-degree-measurements. A.R. Clarke instituted an extensive
series of comparisons at Southampton (see _Comparisons of Standards of
Length of England, France, Belgium, Prussia, Russia, India and
Australia, made at the Ordnance Survey Office, Southampton, 1866_, and
a paper in the _Philosophical Transactions_ for 1873, by Lieut.-Col.
A.R. Clarke, C.B., R.E., on the further comparisons of the standards
of Austria, Spain, the United States, Cape of Good Hope and Russia) and
found that 1 toise = 6.39453348 ft., 1 metre = 3.28086933 ft.

In 1875 a number of European states concluded the metre convention, and
in 1877 an international weights-and-measures bureau was established at
Breteuil. Until this time the metre was determined by the end-surfaces
of a platinum rod (_mètre des archives_); subsequently, rods of
platinum-iridium, of cross-section H, were constructed, having engraved
lines at both ends of the bridge, which determine the distance of a
metre. There were thirty of the rods which gave as accurately as
possible the length of the metre; and these were distributed among the
different states (see WEIGHTS AND MEASURES). Careful comparisons with
several standard toises showed that the metre was not exactly equal to
443,296 lines of the toise, but, in round numbers, 1/75000 of the length
smaller. The metre according to the older relation is called the "legal
metre," according to the new relation the "international metre." The
values are (see _Europ. Längengradmessung_, i. p. 230):--

  Legal metre = 3.28086933 ft., International metre = 3.2808257 ft.

The values of a given above are in terms of the international metre; the
earlier ones in legal metres, while the gravity formulae are in
international metres.


_The International Geodetic Association (Internationale Erdmessung)._

On the proposition of the Prussian lieutenant-general, Johann Jacob
Baeyer, a conference of delegates of several European states met at
Berlin in 1862 to discuss the question of a "Central European
degree-measurement." The first general conference took place at Berlin
two years later; shortly afterwards other countries joined the movement,
which was then named "The European degree-measurement." From 1866 till
1886 Prussia had borne the expense incident to the central bureau at
Berlin; but when in 1886 the operations received further extension and
the title was altered to "The International Earth-measurement" or
"International Geodetic Association," the co-operating states made
financial contributions to this purpose. The central bureau is
affiliated with the Prussian Geodetic Institute, which, since 1892, has
been situated on the Telegraphenberg near Potsdam. After Baeyer's death
Prof. Friedrich Robert Helmert was appointed director. The funds are
devoted to the advancement of such scientific works as concern all
countries and deal with geodetic problems of a general or universal
nature. During the period 1897-1906 the following twenty-one countries
belonged to the association:--Austria, Belgium, Denmark, England,
France, Germany, Greece, Holland, Hungary, Italy, Japan, Mexico, Norway,
Portugal, Rumania, Russia, Servia, Spain, Sweden, Switzerland and the
United States of America. At the present time general conferences take
place every three years.[10]

Baeyer projected the investigation of the curvature of the meridians and
the parallels of the mathematical surface of the earth stretching from
Christiania to Palermo for 12 degrees of longitude; he sought to
co-ordinate and complete the network of triangles in the countries
through which these meridians passed, and to represent his results by a
common unit of length. This proposition has been carried out, and
extended over the greater part of Europe; as a matter of fact, the
network has, with trifling gaps, been carried over the whole of western
and central Europe, and, by some chains of triangles, over European
Russia. Through the co-operation of France, the network has been
extended into north Africa as far as the geographical latitude of 32°;
in Greece a network, united with those of Italy and Bosnia, has been
carried out by the Austrian colonel, Heinrich Hartl; Servia has
projected similar triangulations; Rumania has begun to make the triangle
measurements, and three base lines have been measured by French
officers with Brunner's apparatus. At present, in Rumania, there is
being worked a connexion between the arc of parallel in lat. 47°/48° in
Russia (stretching from Astrakan to Kishinev) with Austria-Hungary. In
the latter country and in south Bavaria the connecting triangles for
this parallel have been recently revised, as well as the French chain on
the Paris parallel, which has been connected with the German net by the
co-operation of German and French geodesists. This will give a long arc
of parallel, really projected in the first half of the 19th century. The
calculation of the Russian section gives, with an assumed ellipticity of
1/299.15, the value a = 6377350 metres; this is rather uncertain, since
the arc embraces only 19° in longitude.

We may here recall that in France geodetic studies have recovered their
former expansion under the vigorous impulse of Colonel (afterwards
General) François Perrier. When occupied with the triangulation of
Algeria, Colonel Perrier had conceived the possibility of the geodetic
junction of Algeria to Spain, over the Mediterranean; therefore the
French meridian line, which was already connected with England, and was
thus produced to the 60th parallel, could further be linked to the
Spanish triangulation, cross thence into Algeria and extend to the
Sahara, so as to form an arc of about 30° in length. But it then became
urgent to proceed to a new measurement of the French arc, between
Dunkirk and Perpignan. In 1869 Perrier was authorized to undertake that
revision. He devoted himself to that work till the end of his career,
closed by premature death in February 1888, at the very moment when the
_Dépôt de la guerre_ had just been transformed into the Geographical
Service of the Army, of which General F. Perrier was the first director.
His work was continued by his assistant, Colonel (afterwards General)
J.A.L. Bassot. The operations concerning the revision of the French arc
were completed only in 1896. Meanwhile the French geodesists had
accomplished the junction of Algeria to Spain, with the help of the
geodesists of the Madrid Institute under General Carlos Ibañez (1879),
and measured the meridian line between Algiers and El Aghuat (1881).
They have since been busy in prolonging the meridians of El Aghuat and
Biskra, so as to converge towards Wargla, through Ghardaïa and Tuggurt.
The fundamental co-ordinates of the Panthéon have also been obtained
anew, by connecting the Panthéon and the Paris Observatory with the five
stations of Bry-sur-Marne, Morlu, Mont Valérien, Chatillon and
Montsouris, where the observations of latitude and azimuth have been
effected.[11]

According to the calculations made at the central bureau of the
international association on the great meridian arc extending from the
Shetland Islands, through Great Britain, France and Spain to El Aghuat in
Algeria, a = 6377935 metres, the ellipticity being assumed as 1/299.15.
The following table gives the difference: astronomical-geodetic latitude.
The net does not follow the meridian exactly, but deviates both to the
west and to the east; actually, the meridian of Greenwich is nearer the
mean than that of Paris (Helmert, _Grösse d. Erde_).

  _West Europe-Africa Meridian-arc._[12]

  Name.                Latitude.   A.-G.
                        °   '        "
  Saxavord             60  49.6    -4.0
  Balta                60  45.0    -6.1
  Ben Hutig            58  33.1    +0.3
  Cowhythe             57  41.1    +7.3
  Great Stirling       57  27.8    -2.3
  Kellie Law           56  14.9    -3.7
  Calton Hill          55  57.4    +3.5
  Durham               54  46.1    -0.9
  Burleigh Moor        54  34.3    +2.1
  Clifton Beacon       53  27.5    +1.3
  Arbury Hill          52  13.4    -3.0
  Greenwich            51  28.6    -2.5
  Nieuport             51   7.8    -0.4
  Rosendaël            51   2.7    -0.9
  Lihons               49  49.9    +0.5
  Panthéon             48  50.8    -0.0
  Chevry               48   0.5    +2.2
  Saligny le Vif       47   2.7    +3.0
  Arpheuille           46  13.7    +6.3
  Puy de Dôme          45  46.5    +7.0
  Rodez                44  21.4    +1.7
  Carcassonne          43  13.3    +0.7
  Rivesaltes           42  45.2    -0.7
  Montolar             41  38.5    +3.6
  Lérida               41  37.0    -0.2
  Javalon              40  13.8    -0.2
  Desierto             40   5.0    -4.5
  Chinchilla           38  55.2    +2.2
  Mola de Formentera   38  39.9    -1.2
  Tetíca               37  15.2    +3.5
  Roldan               36  56.6    -6.0
  Conjuros             36  44.4   -12.6
  Mt. Sabiha           35  39.6    +6.5
  Nemours              35   5.8    +7.4
  Bouzaréah            36  48.0    +2.9
  Algiers (Voirol)     36  45.1    -9.1
  Guelt ès Stel        35   7.8    -1.0
  El Aghuat            33  48.0    -2.8

[Illustration]

While the radius of curvature of this arc is obviously not uniform
(being, in the mean, about 600 metres greater in the northern than in
the southern part), the Russo-Scandinavian meridian arc (from 45° to
70°), on the other hand, is very uniformly curved, and gives, with an
ellipticity of 1/299.15, a = 6378455 metres; this arc gives the
plausible value 1/298.6 for the ellipticity. But in the case of this arc
the orographical circumstances are more favourable.

The west-European and the Russo-Scandinavian meridians indicate another
anomaly of the geoid. They were connected at the Central Bureau by means
of east-to-west triangle chains (principally by the arc of parallel
measurements in lat. 52°); it was shown that, if one proceeds from the
west-European meridian arcs, the differences between the astronomical
and geodetic latitudes of the Russo-Scandinavian arc become some 4"
greater.[13]

The central European meridian, which passes through Germany and the
countries adjacent on the north and south, is under review at Potsdam
(see the publications of the Kgl. Preuss. Geod. Inst., _Lotabweichungen_,
Nos. 1-3). Particular notice must be made of the Vienna meridian, now
carried southwards to Malta. The Italian triangulation is now complete,
and has been joined with the neighbouring countries on the north, and
with Tunis on the south.

The United States Coast and Geodetic Survey has published an account of
the transcontinental triangulation and measurement of an arc of the
parallel of 39°, which extends from Cape May (New Jersey), on the
Atlantic coast, to Point Arena (California), on the Pacific coast, and
embraces 48° 46' of longitude, with a linear development of about 4225
km. (2625 miles). The triangulation depends upon ten base-lines, with an
aggregate length of 86 km. the longest exceeding 17 km. in length, which
have been measured with the utmost care. In crossing the Rocky
Mountains, many of its sides exceed 100 miles in length, and there is
one side reaching to a length of 294 km., or 183 miles; the altitude of
many of the stations is also considerable, reaching to 4300 metres, or
14,108 ft., in the case of Pike's Peak, and to 14,421 ft. at Elbert
Peak, Colo. All geometrical conditions subsisting in the triangulation
are satisfied by adjustment, inclusive of the required accord of the
base-lines, so that the same length for any given line is found, no
matter from what line one may start.[14]

Over or near the arc were distributed 109 latitude stations, occupied
with zenith telescopes; 73 azimuth stations; and 29 telegraphically
determined longitudes. It has thus been possible to study in a very
complete manner the deviations of the vertical, which in the mountainous
regions sometimes amount to 25 seconds, and even to 29 seconds.

With the ellipticity 1/299.15, a = 6377897 ± 65 metres (prob. error); in
this calculation, however, some exceedingly perturbed stations are
excluded; for the employed stations the mean perturbation in longitude
is ± 4.9" (zenith-deflection east-to-west ± 3.8").

The computations relative to another arc, the "eastern oblique arc of
the United States," are also finished.[15] It extends from Calais
(Maine) in the north-east, to the Gulf of Mexico, and terminates at New
Orleans (Louisiana), in the south. Its length is 2612 km. (1623 miles),
the difference of latitude 15° 1', and of longitude 22° 47'. In the
main, the triangulation follows the Appalachian chain of mountains,
bifurcating once, so as to leave an oval space between the two branches.
It includes among its stations Mount Washington (1920 metres) and Mount
Mitchell (2038 metres). It depends upon six base-lines, and the
adjustment is effected in the same manner as for the arc of the
parallel. The astronomical data have been afforded by 71 latitude
stations, 17 longitude stations, and 56 azimuth stations, distributed
over the whole extent of the arc. The resulting dimensions of an
osculating spheroid were found to be

  a = 6378157 metres ± 90 (prob. error),
  e(ellipticity) = 1/304.5 ± 1.9 (prob. error).

With the ellipticity 1/399.15, a = 6378041 metres ± 80 (prob. er.).

During the years 1903-1906 the United States Coast and Geodetic Survey,
under the direction of O.H. Tittmann and the special management of John
F. Hayford, executed a calculation of the best ellipsoid of rotation for
the United States. There were 507 astronomical determinations employed,
all the stations being connected through the net-work of triangles. The
observed latitudes, longitude and azimuths were improved by the
attractions of the earth's crust on the hypothesis of isostasis for
three depths of the surface of 114, 121 and 162 km., where the isostasis
is complete. The land-masses, within the distance of 4126 km., were
taken into consideration. In the derivation of an ellipsoid of rotation,
the first case proved itself the most favourable, and there resulted:--

  a = 6378283 metres ± 74 (prob. er.), ellipticity
    = 1/297.8 ± 0.9 (prob. er.).

The most favourable value for the depth of the isostatic surface is
approximately 114 km.

The measurement of a great meridian arc, in long. 98° W., has been
commenced; it has a range of latitude of 23°, and will extend over 50°
when produced southwards and northwards by Mexico and Canada. It may
afterwards be connected with the arc of Quito. A new measurement of the
meridian arc of Quito was executed in the years 1901-1906 by the
_Service géographique_ of France under the direction of the Académie des
Sciences, the ground having been previously reconnoitred in 1899. The
new arc has an amplitude in latitude of 5° 53' 33", and stretches from
Tulcan (lat. 0° 48' 25") on the borders of Columbia and Ecuador, through
Columbia to Payta (lat. -5° 5' 8") in Peru. The end-points, at which the
chain of triangles has a slight north-easterly trend, show a longitude
difference of 3°. Of the 74 triangle points, 64 were latitude stations;
6 azimuths and 8 longitude-differences were measured, three base-lines
were laid down, and gravity was determined from six points, in order to
maintain indications over the general deformation of the geoid in that
region. Computations of the attraction of the mountains on the
plumb-line are also being considered. The work has been much delayed by
the hardships and difficulties encountered. It was conducted by
Lieut.-Colonel Robert Bourgeois, assisted by eleven officers and
twenty-four soldiers of the geodetic branch of the _Service
géographique_. Of these officers mention may be made of Commandant E.
Maurain, who retired in 1904 after suffering great hardships; Commandant
L. Massenet, who died in 1905; and Captains I. Lacombe, A. Lallemand,
and Lieut. Georges Perrier (son of General Perrier). It is conceivable
that the chain of triangles in longitude 98° in North America may be
united with that of Ecuador and Peru: a continuous chain over the whole
of America is certainly but a question of time. During the years
1899-1902 the measurement of an arc of meridian was made in the extreme
north, in Spitzbergen, between the latitudes 76° 38' and 80° 50',
according to the project of P.G. Rosén. The southern part was determined
by the Russians--O. Bäcklund, Captain D.D. Sergieffsky, F.N.
Tschernychev, A. Hansky and others--during 1899-1901, with the aid of 1
base-line, 15 trigonometrical, 11 latitude and 5 gravity stations. The
northern part, which has one side in common with the southern part, has
been determined by Swedes (Professors Rosén, father and son, E. Jäderin,
T. Rubin and others), who utilized 1 base-line, 9 azimuth measurements,
18 trigonometrical, 17 latitude and 5 gravity stations. The party worked
under excessive difficulties, which were accentuated by the arctic
climate. Consequently, in the first year, little headway was made.[16]

Sir David Gill, when director of the Royal Observatory, Cape Town,
instituted the magnificent project of working a latitude-degree
measurement along the meridian of 30° long. This meridian passes through
Natal, the Transvaal, by Lake Tanganyika, and from thence to Cairo;
connexion with the Russo-Scandinavian meridian arc of the same longitude
should be made through Asia Minor, Turkey, Bulgaria and Rumania. With
the completion of this project a continuous arc of 105° in latitude will
have been measured.[17]

Extensive triangle chains, suitable for latitude-degree measurements,
have also been effected in Japan and Australia.

Besides, the systematization of gravity measurements is of importance,
and for this purpose the association has instituted many reforms. It has
ensured that the relative measurements made at the stations in different
countries should be reduced conformably with the absolute determinations
made at Potsdam; the result was that, in 1906, the intensities of
gravitation at some 2000 stations had been co-ordinated. The intensity
of gravity on the sea has been determined by the comparison of
barometric and hypsometric observations (Mohn's method). The
association, at the proposal of Helmert, provided the necessary funds
for two expeditions:--English Channel--Rio de Janeiro, and the Red
Sea--Australia--San Francisco--Japan. Dr O. Hecker of the central bureau
was in charge; he successfully overcame the difficulties of the work,
and established the tenability of the isostatic hypothesis, which
necessitates that the intensity of gravity on the deep seas has, in
general, the same value as on the continents (without regard to the
proximity of coasts).[18]

As the result of the more recent determinations, the ellipticity,
compression or flattening of the ellipsoid of the earth may be assumed
to be very nearly 1/298.3; a value determined in 1901 by Helmert from
the measurements of gravity. The semi-major axis, a, of the meridian
ellipse may exceed 6,378,000 inter. metres by about 200 metres. The
central bureau have adopted, for practical reasons, the value 1/299.15,
after Bessel, for which tables exist; and also the value a =
6377397.155(1 + 0.0001).

The methods of theoretical astronomy also permit the evaluation of these
constants. The semi-axis a is calculable from the parallax of the moon
and the acceleration of gravity on the earth; but the results are
somewhat uncertain: the ellipticity deduced from lunar perturbations is
1/297.8 ± 2 (Helmert, _Geodäsie_, ii. pp. 460-473); William Harkness
(_The Solar Parallax and its related Constants_, 1891) from all possible
data derived the values: ellipticity = 1/300.2 ± 3, a = 6377972 ± 125
metres. Harkness also considered in this investigation the relation of
the ellipticity to precession and nutation; newer investigations of the
latter lead to the limiting values 1/296, 1/298 (Wiechert). It was
clearly noticed in this method of determination that the influence of
the assumption as to the density of the strata in the interior of the
earth was but very slight (Radau, _Bull. astr._ ii. (1885) 157). The
deviations of the geoid from the flattened ellipsoid of rotation with
regard to the heights (the directions of normals being nearly the same)
will scarcely exceed ± 100 metres (Helmert).[19]

The basis of the degree- and gravity-measurements is actually formed by
a stationary sea-surface, which is assumed to be level. However, by the
influence of winds and ocean currents the mean surface of the sea near
the coasts (which one assumes as the fundamental sea-surface) can
deviate somewhat from a level surface. According to the more recent
levelling it varies at the most by only some decimeters.[20]

It is well known that the masses of the earth are continually undergoing
small changes; the earth's crust and sea-surface reciprocally oscillate,
and the axis of rotation vibrates relatively to the body of the earth.
The investigation of these problems falls in the programme of the
Association. By continued observations of the water-level on sea-coasts,
results have already been obtained as to the relative motions of the
land and sea (cf. GEOLOGY); more exact levelling will, in the course of
time, provide observations on countries remote from the sea-coast. Since
1900 an international service has been organized between some
astronomical stations distributed over the north parallel of 39° 8', at
which geographical latitudes are observed whenever possible. The
association contributes to all these stations, supporting four entirely:
two in America, one in Italy, and one in Japan; the others partially
(Tschardjui in Russia, and Cincinnati observatory). Some observatories,
especially Pulkowa, Leiden and Tokyo, take part voluntarily. Since 1906
another station for South America and one for Australia in latitude -31°
55' have been added. According to the existing data, geographical
latitudes exhibit variations amounting to ±0.25", which, for the greater
part, proceed from a twelve- and a fourteen-month period.[21]
     (A. R. C; F. R. H.)


FOOTNOTES:

  [1] _Eratosthenes Batavus, seu de terrae ambitus vera quantitate
    suscitatus, a Willebrordo Snellio, Lugduni-Batavorum_ (1617).

  [2] O. Callandreau, "Mémoire sur la théorie de la figure des
    planètes," _Ann. obs. de Paris_ (1889); G.H. Darwin, "The Theory of
    the Figure of the Earth carried to the Second Order of Small
    Quantities," _Mon. Not. R.A.S._, 1899; E. Wiechert, "Über die
    Massenverteilung im Innern der Erde," _Nach. d. kön. G. d. W. zu
    Gött._, 1897.

  [3] See I. Todhunter, _Proc. Roy. Soc._, 1870.

  [4] J.H. Jeans, "On the Vibrations and Stability of a Gravitating
    Planet," _Proc. Roy. Soc._ vol. 71; G.H. Darwin, "On the Figure and
    Stability of a liquid Satellite," _Phil. Trans._ 206, p. 161; A.E.H.
    Love, "The Gravitational Stability of the Earth," _Phil. Trans._ 207,
    p. 237; _Proc. Roy. Soc._ vol. 80.

  [5] _Survey of India_, "The Attraction of the Himalaya Mountains upon
    the Plumb Line in India" (1901), p. 98.

  [6] _Account of Experiments to Determine the Figure of the Earth by
    means of a Pendulum vibrating Seconds in Different Latitudes_ (1825).

  [7] Helmert, _Theorien d. höheren Geod._ ii., Leipzig, 1884.

  [8] Helmert, _Sitzber. d. kgl. preuss. Ak. d. Wiss. zu Berlin_
    (1901), p. 336.

  [9] "Bestimmung der absoluten Grösse der Schwerkraft zu Potsdam mit
    Reversionspendeln" (_Veröffentlichung des kgl. preuss. Geod. Inst._,
    N.F., No. 27).

  [10] _Die Königl. Observatorien für Astrophysik, Meteorologie und
    Geodäsie bei Potsdam_ (Berlin, 1890); _Verhandlungen der I.
    Allgemeinen Conferenz der Bevollmächtigten zur mitteleurop.
    Gradmessung_, October, 1864, in Berlin (Berlin, 1865); A. Hirsch,
    _Verhandlungen der VIII. Allg. Conf. der Internationalen Erdmessung_,
    October, 1886, in Berlin (Berlin, 1887); and _Verhandlungen der XI.
    Allg. Conf. d. I. E._, October, 1895, in Berlin (1896).

  [11] Ibañez and Perrier, _Jonction géod. et astr. de l'Algérie avec
    l'Espagne_ (Paris, 1886); _Mémorial du dépôt général de la guerre_,
    t. xii.: _Nouvelle méridienne de France_ (Paris, 1885, 1902, 1904);
    _Comptes rendus des séances de la 12^e-19^e conférence générale de
    l'Assoc. Géod. Internat._, 1898 at Stuttgart, 1900 at Paris, 1903 at
    Copenhagen, 1906 at Budapest (Berlin, 1899, 1901, 1904, 1908); A.
    Ferrero, _Rapport sur les triangulations, prés. à la 12^e conf. gén.
    1898_.

  [12] R. Schumann, _C. r. de Budapest_, p. 244.

  [13] O. and A. Börsch, "Verbindung d. russ.-skandinav. mit der
    franz.-engl. Breitengradmessung" (_Verhandlungen der 9. Allgem. Conf.
    d. I. E. in Paris, 1889_, Ann. xi.).

  [14] U.S. Coast and Geodetic Survey; H.S. Pritchett, superintendent.
    _The Transcontinental Triangulation and the American Arc of the
    Parallel_, by C.A. Schott (Washington, 1900).

  [15] U.S. Coast and Geodetic Survey; O.H. Tittmann, superintendent.
    _The Eastern Oblique Arc of the United States_, by C.A. Schott
    (1902).

  [16] _Missions scientifiques pour la mesure d'un arc de méridien au
    Spitzberg entreprises en 1899-1902 sous les auspices des
    gouvernements russe et suédois._ _Mission russe_ (St Pétersbourg,
    1904); _Mission suédoise_ (Stockholm, 1904).

  [17] Sir David Gill, _Report on the Geodetic Survey of South Africa,
    1833-1892_ (Cape Town, 1896), vol. ii. 1901, vol. iii. 1905.

  [18] O. Hecker, _Bestimmung der Schwerkraft a. d. Atlantischen Ozean_
    (Veröffentl. d. Kgl. Preuss. Geod. Inst. No. 11), Berlin, 1903.

  [19] F.R. Helmert. "Neuere Fortschritte in der Erkenntnis der math.
    Erdgestalt" (_Verhandl. des VII. Internationalen
    Geographen-Kongresses, Berlin, 1899_), London, 1901.

  [20] C. Lallemand, "Rapport sur les travaux du service du nivellement
    général de la France, de 1900 à 1906" (_Comp. rend. de la 14^e conf.
    gén. de l'Assoc. Géod-Intern., 1903_, p. 178).

  [21] T. Albrecht, _Resultate des internat. Breitendienstes_, i. and
    ii. (Berlin, 1903 and 1906); F. Klein and A. Sommerfeld, _Über die
    Theorie des Kreisels_, iii. p. 672; R. Spitaler, "Die periodischen
    Luftmassenverschiebungen und ihr Einfluss auf die Lagenänderung der
    Erdaxe" (_Petermanns Mitteilungen, Ergänzungsheft_, 137); S. Newcomb,
    "Statement of the Theoretical Laws of the Polar Motion"
    (_Astronomical Journal_, 1898, xix. 158); F.R. Helmert, "Zur
    Erklärung der beobachteten Breitenänderungen" (_Astr. Nachr._ No.
    3014); J. Weeder, "The 14-monthly period of the motion of the Pole
    from determinations of the azimuth of the meridian marks of the
    Leiden observatory" (_Kon. Ak. van Wetenschappen to Amsterdam_,
    1900); A. Sokolof, "Détermination du mouvement du pôle terr. au moyen
    des mires méridiennes de Poulkovo" (_Mél. math. et astr._ vii.,
    1894); J. Bonsdorff, "Beobachtungen von [delta] Cassiopejae mit dem
    grossen Zenitteleskop" (_Mitteilungen der Nikolai-Hauptsternwarte zu
    Pulkowo_, 1907); J. Larmor and E.H. Hills, "The irregular movement of
    the Earth's axis of rotation: a contribution towards the analysis of
    its causes" (_Monthly Notices R.A.S._, 1906, lxvii. 22); A.S.
    Cristie, "The latitude variation Tide" (_Phil. Soc. of Wash._, 1895,
    _Bull._ xiii. 103); H.G. van de Sande Bakhuysen, "Über die Änderung
    der Polhöhe" (_Astr. Nachr._ No. 3261); A.V. Bäcklund, "Zur Frage
    nach der Bewegung des Erdpoles" (_Astr. Nachr._ No. 3787); R.
    Schumann, "Über die Polhöhenschwankung" (_Astr. Nachr._ No. 3873);
    "Numerische Untersuchung" (_Ergänzungshefte zu den Astr. Nachr._ No.
    11); _Weitere Untersuchungen_ (No. 4142); _Bull. astr._, 1900, June,
    report of different theoretical memoirs.



EARTH CURRENTS. After the invention of telegraphy it was soon found that
telegraph lines in which the circuit is completed by the earth are
traversed by natural electric currents which occasionally interfere
seriously with their use, and which are known as "earth currents."

1. Amongst the pioneers in investigating the subject were several English
telegraphists, e.g. W.H. Barlow (1) and C.V. Walker (2), who were in
charge respectively of the Midland and South-Eastern telegraph systems.
Barlow noticed the existence of a more or less regular diurnal variation,
and the result--confirmed by all subsequent investigators--that earth
currents proper occur in a line only when both ends are earthed. Walker,
as the result of general instructions issued to telegraph clerks,
collected numerous statistics as to the phenomena during times of large
earth currents. His results and those given by Barlow both indicate that
the lines to suffer most from earth currents in England have the general
direction N.E. to S.W. As Walker points out, it is the direction of the
terminal plates relative to one another that is the essential thing. At
the same time he noticed that whilst at any given instant the currents in
parallel lines have with rare exceptions the same direction, some lines
show normally stronger currents than others, and he suggested that
differences in the geological structure of the intervening ground might
be of importance. This is a point which seems still somewhat obscure.

Our present knowledge of the subject owes much to practical men, but
even in the early days of telegraphy the fact that telegraph systems are
commercial undertakings, and cannot allow the public to wait the
convenience of science, was a serious obstacle to their employment for
research. Thus Walker feelingly says, when regretting his paucity of
data during a notable earth current disturbance: "Our clerks were at
their wits' end to clear off the telegrams.... At a time when
observations would have been very highly acceptable they were too much
occupied with their ordinary duties." Some valuable observations have,
however, been made on long telegraph lines where special facilities have
been given.

Amongst these may be mentioned the observations on French lines in 1883
described by E.E. Blavier (3), and those on two German lines
Berlin-Thorn and Berlin-Dresden during 1884 to 1888 discussed by B.
Weinstein (4).

2. Of the experimental lines specially constructed perhaps the best
known are the Greenwich lines instituted by Sir G.B. Airy (5), the lines
at Pawlowsk due to H. Wild (6), and those at Parc Saint Maur, near Paris
(7).

_Experimental Lines._--At Greenwich observations were commenced in 1865,
but there have been serious disturbances due to artificial currents from
electric railways for many years. There are two lines, one to Dartford
distant about 10 m., in a direction somewhat south of east, the other to
Croydon distant about 8 m., in a direction west of south.

Information from a single line is incomplete, and unless this is clearly
understood erroneous ideas may be derived. The times at which the
current is largest and least, or when it vanishes, in an east-west line,
tell nothing directly as to the amplitude at the time of the resultant
current. The lines laid down at Pawlowsk in 1883 lay nearly in and
perpendicular to the geographical meridian, a distinct desideratum, but
were only about 1 km. long. The installation at Parc Saint Maur,
discussed by T. Moureaux, calls for fuller description. There are three
lines, one having terminal earth plates 14.8 km. apart in the
geographical meridian, a second having its earth plates due east and
west of one another, also 14.8 km. apart, and the third forming a closed
circuit wholly insulated from the ground. In each of the three lines is
a Deprez d'Arsonval galvanometer. Light reflected from the galvanometer
mirrors falls on photographic paper wound round a drum turned by
clockwork, and a continuous record is thus obtained.

3. Each galvanometer has a resistance of about 200 ohms, but is shunted
by a resistance of only 2 ohms. The total effective resistances in the
N.-S. and E.-W. lines are 225 and 348 ohms respectively. If i is the
current recorded, L, g and s the resistances of the line, galvanometer
and shunt respectively, then E, the difference of potential between the
two earth plates, is given by

  E = i(1 + g/s) {L + gs/(g + s)}.

To calibrate the record, a Daniell cell is put in a circuit including
1000 ohms and the three galvanometers as shunted. If i' be the current
recorded, e the E.M.F. of the cell, then e = i'(1 + g/s){1000 + 3gs/(g +
s)}. Under the conditions at Parc Saint Maur we may write 2 for gs/(g +
s), and 1.072 for e, and thence we have approximately E = 0.240(i/i')
for the N.-S. line, and E = -0.371(i/i') for the E.-W. line.

The method of standardization assumes a potential difference between
earth plates which varies slowly enough to produce a practically steady
current. There are several causes producing currents in a telegraph wire
which do not satisfy this limitation. During thunderstorms surgings may
arise, at least in overhead wires, without these being actually struck.
Again, if the circuit includes a variable magnetic field, electric
currents will be produced independently of any direct source of
potential difference. In the third circuit at Parc Saint Maur, where no
earth plates exist, the current must be mainly due to changes in the
earth's vertical magnetic field, with superposed disturbances due to
atmospheric electricity or aerial waves. Even in the other circuits,
magnetic and atmospheric influences play some part, and when their
contribution is important, the galvanometer deflection has an uncertain
value. What a galvanometer records when traversed by a suddenly varying
current depends on other things than its mere resistance.

Even when the current is fairly steady, its exact significance is not
easily stated. In the first place there is usually an appreciable E.M.F.
between a plate and the earth in contact with it, and this E.M.F. may
vary with the temperature and the dryness of the soil. Naturally one
employs similar plates buried to the same depth at the two ends, but
absolute identity and invariability of conditions can hardly be secured.
In some cases, in short lines (8), there is reason to fear that plate
E.M.F.'s have been responsible for a good deal that has been ascribed to
true earth currents. With deep earth plates, in dry ground, this source
of uncertainty can, however, enter but little into the diurnal
inequality.

4. Another difficulty is the question of the resistance in the earth
itself. A given E.M.F. between plates 10 m. apart may mean very
different currents travelling through the earth, according to the
chemical constitution and condition of the surface strata.

According to Professor A. Schuster (9), if [rho] and [rho]' be the
specific resistances of the material of the wire and of the soil, the
current i which would pass along an underground cable formed of actual
soil, equal in diameter to the wire connecting the plates, is given by i
= i'[rho]/[rho]', where i' is the observed current in the wire. As
[rho]' will vary with the depth, and be different at different places
along the route, while discontinuities may arise from geological faults,
water channels and so on, it is clear that even the most careful
observations convey but a general idea as to the absolute intensity of
the currents in the earth itself. In Schuster's formula, as in the
formulae deduced for Parc Saint Maur, it is regarded as immaterial
whether the wire connecting the plates is above or below ground. This
view is in accordance with records obtained by Blavier (3) from two
lines between Paris and Nancy, the one an air line, the other
underground.

5. The earliest quantitative results for the regular diurnal changes in
earth currents are probably those deduced by Airy (5) from the records
at Greenwich between 1865 and 1867. Airy resolved the observed currents
from the two Greenwich lines in and perpendicular to the _magnetic_
meridian (then about 21° to the west of astronomical north). The
information given by Airy as to the precise meaning of the quantities he
terms "magnetic tendency" to north and to west is somewhat scanty, but
we are unlikely to be much wrong in accepting his figures as
proportional to the earth currents from magnetic east to west and from
magnetic north to south respectively. Airy gives mean hourly values for
each month of the year. The corresponding mean diurnal inequality for
the whole year appears in Table 1., the unit being arbitrary. In every
month the algebraic mean of the 24 hourly values represented a current
from north to south in the magnetic meridian, and from east to west in
the perpendicular direction; in the same arbitrary units used in Table
I. the mean values of these two "constant" currents were respectively
777 and 559.

6. _Diurnal Variation._--Probably the most complete records of diurnal
variation are those discussed by Weinstein (4), which depend on several
years' records on lines from Berlin to Dresden and to Thorn. Relative to
Berlin the geographical co-ordinates of the other two places are:

  Thorn       0° 29' N. lat. 5° 12' E. long.
  Dresden     1° 28' S. lat. 0° 21' E. long.

Thus the Berlin-Dresden line was directed about 8½° east of south, and
the Berlin-Thorn line somewhat more to the north of east. The latter
line had a length about 2.18 times that of the former. The resistances
in the two lines were made the same, so if we suppose the difference of
potential between earth plates along a given direction to vary as their
distance apart, the current observed in the Thorn-Berlin line has to be
divided by 2.18 to be comparable with the other. In this way, resolving
along and perpendicular to the geographical meridian, Weinstein gives as
proportional to the earth currents from east to west and from south to
north respectively

  J = 0.147i' + 0.435i, and J' = 0.989i' - 0.100i,

where i and i' are the observed currents in the Thorn-Berlin and
Dresden-Berlin lines respectively, both being counted positive when
flowing towards Berlin.

It is tacitly assumed that the average earth conductivity is the same
between Berlin and Thorn as between Berlin and Dresden. It should also
be noticed that local time at Berlin and Thorn differs by fully 20
minutes, while the crests of the diurnal variations in _short_ lines at
the two places would probably occur about the same local time. The
result is probably a less sharp occurrence of maxima and minima, and a
relatively smaller range, than in a short line having the same
orientation.

  TABLE I.

  +-----------------------------------------------------+------------------------------+
  |       Mean Diurnal Inequalities for the year.       |Numerical Values of resultant |
  |                                                     |           current.           |
  +----------------------+------------------------------+------------------------------+
  |      Greenwich.      |     Thorn-Berlin-Dresden.    |    Thorn-Berlin-Dresden.     |
  +--------+-------------+--------+-------+------+------+------------------------------+
  |        |North | East | Berlin | Thorn |North | East |   Mean hourly values from    |
  |  Hour. |  to  |  to  |   to   |  to   |  to  |  to  +-----+-------+--------+-------+
  |        |South | West |Dresden.|Berlin.|South | West |Year.|Winter.|Equinox.|Summer.|
  |        |(Mag.)|(Mag.)|        |       |(Ast.)|(Ast.)|     |       |        |       |
  +--------+------+------+--------+-------+------+------+-----+-------+--------+-------+
  |    1   |  -94 |  -41 |   -17  |  -13  |  -20 |  -10 |  81 |   94  |    51  |   98  |
  |    2   |  -68 |  -24 |    -6  |  -13  |   -9 |  -11 |  84 |  115  |    39  |   97  |
  |    3   |  -44 |   -8 |    -1  |   -1  |   -1 |   -1 |  84 |  113  |    31  |  108  |
  |    4   |  -18 |   +9 |   -20  |  +15  |  -17 |  +17 | 101 |   94  |    58  |  127  |
  |    5   |  -30 |   -1 |   -79  |  +21  |  -74 |  +32 | 122 |   58  |    78  |  230  |
  |    6   |  -63 |  -33 |  -139  |   +5  | -136 |  +26 | 148 |   80  |   139  |  225  |
  |    7   | -121 |  -80 |  -138  |  -36  | -144 |  -14 | 166 |  155  |   206  |  136  |
  |    8   | -175 | -123 |    -7  |  -98  |  -28 |  -92 | 203 |  152  |   185  |  271  |
  |    9   | -156 | -137 |  +249  | -156  | +212 | -184 | 305 |   67  |   272  |  575  |
  |   10   |  -43 |  -77 |  +540  | -184  | +494 | -254 | 557 |  232  |   628  |  811  |
  |   11   |  +82 |   +1 |  +722  | -165  | +678 | -263 | 728 |  411  |   885  |  887  |
  |  Noon  | +207 |  +66 |  +673  | -107  | +642 | -200 | 675 |  441  |   848  |  735  |
  |    1   | +245 |  +94 |  +404  |  -20  | +395 |  -79 | 400 |  284  |   510  |  406  |
  |    2   | +205 | +113 |   +35  |  +55  |  +46 |  +47 |  98 |   68  |   103  |  125  |
  |    3   | +153 |  +97 |  -261  |  +99  | -237 | +132 | 272 |  136  |   355  |  324  |
  |    4   | +159 | +108 |  -397  | +114  | -368 | +167 | 404 |  218  |   503  |  492  |
  |    5   | +167 | +118 |  -391  | +108  | -363 | +160 | 397 |  206  |   453  |  532  |
  |    6   | +125 |  +95 |  -311  |  +96  | -287 | +137 | 319 |  176  |   333  |  446  |
  |    7   |  +43 |  +55 |  -237  |  +85  | -216 | +115 | 247 |  180  |   250  |  312  |
  |    8   |  -22 |   +4 |  -191  |  +74  | -173 |  +98 | 201 |  207  |   217  |  181  |
  |    9   | -115 |  -49 |  -168  |  +59  | -153 |  +81 | 174 |  208  |   194  |  120  |
  |   10   | -138 |  -74 |  -135  |  +40  | -125 |  +58 | 138 |  155  |   149  |  111  |
  |   11   | -136 |  -70 |   -84  |  +18  |  -79 |  +29 |  89 |   64  |    95  |  107  |
  |Midnight| -147 |  -80 |   -43  |   -2  |  -43 |   +4 |  91 |   42  |   119  |  111  |
  +--------+------+------+--------+-------+------+------+-----+-------+--------+-------+

It was found that the average current derived from a number of
undisturbed days on either line might be regarded as made up of a
"constant part" plus a regular diurnal inequality, the constant part
representing the algebraic mean value of the 24 hourly readings. In both
lines the constant part showed a decided alteration during the third
year--changing sign in one line--in consequence, it is believed, of
alterations made in the earth plates. The constant part was regarded as
a plate effect, and was omitted from further consideration. Table I.
shows in terms of an arbitrary unit--whose relation to that employed for
Greenwich data is unknown--the diurnal inequality in the currents along
the two lines, and the inequalities thence calculated for ideal lines in
and perpendicular to the _geographical_ meridian. Currents are regarded
as positive when directed from Berlin to Dresden and from north to
south, the opposite point of view to that adopted by Weinstein. The
table also shows the mean _numerical_ value of the resultant current
(the "constant" part being omitted) for each hour of the day, for the
year as a whole, and for winter (November to February), equinox (March,
April, September, October) and summer (May to August). There is a marked
double period in both the N.-S. and E.-W. currents. In both cases the
numerically largest currents occur from 10 A.M. to noon, the directions
then being from north to south and from west to east. The currents tend
to die out and change sign about 2 P.M., the numerical magnitude then
rising again rapidly to 4 or 5 P.M. The current in the meridian is
notably the larger. The numerical values assigned to the resultant
current are arithmetic means from the several months composing the
season in question.

7. The mean of the 24 hourly numerical values of the resultant current
for each month of the year a deducible from Weinstein's data--the unit
being the same as before--are given in Table II.

  TABLE II.--_Mean Numerical Value of Resultant Current._

  Jan.  Feb.  March  April  May  June  July  Aug.  Sep.  Oct.  Nov.  Dec.
  152   211    293    328   313   314   337  300   258   235   165   132

There is thus a conspicuous minimum at mid-winter, and but little
difference between the monthly means from April to August. This is
closely analogous to what is seen in the daily range of the magnetic
elements in similar latitudes (see MAGNETISM, TERRESTRIAL). There is
also considerable resemblance between the curve whose ordinates
represent the diurnal inequality in the current passing from north to
south, and the curve showing the hourly change in the westerly component
of the horizontal magnetic force in similar European latitudes.

8. _Relations with Sun-spots, Auroras and Magnetic Storms._--Weinstein
gives curves representing the mean diurnal inequality for separate
years. In both lines the diurnal amplitudes were notably smaller in the
later years which were near sun-spot minimum. This raises a presumption
that the regular diurnal earth currents, like the ranges of the magnetic
elements, follow the 11-year sun-spot period. When we pass to the large
and irregular earth currents, which are of practical interest in
telegraphy, there is every reason to suppose that the sun-spot period
applies. These currents are always accompanied by magnetic disturbances,
and when specially striking by brilliant aurora. One most conspicuous
example of this occurred in the end of August and beginning of September
1859. The magnetic disturbances recorded were of almost unexampled size
and rapidity, the accompanying aurora was extraordinarily brilliant, and
E.M.F.'s of 700 and 800 volts are said to have been reached on telegraph
lines 500 to 600 km. long. It is doubtful whether the disturbances of
1859 have been equalled since, but earth current voltages of the order
of 0.5 volts per mile have been recorded by various authorities, e.g.
Sir W.H. Preece (10).

It was the practice for several years to publish in the _Ann. du bureau
central météorologique_ synchronous magnetic and earth current curves
from Parc Saint Maur corresponding to the chief disturbances of the
year. In most cases there is a marked similarity between the curve of
magnetic declination and that of the north-south earth current. At times
there is also a distinct resemblance between the horizontal force
magnetic curve and that of the east-west earth current, but exceptions
to this are not infrequent. Similar phenomena appear in synchronous
Greenwich records published by Airy in 1868; these show a close
accordance between the horizontal force curves and those of the currents
from magnetic east to west. Originally it was supposed by Airy that
whilst rapid movements in the declination and north-south current curves
sometimes occurred simultaneously, there was a distinct tendency for
the latter to precede the former. More recent examinations of the
Greenwich records by W. Ellis (11), and of the Parc St Maur curves by
Moureaux, have not confirmed this result, and it is now believed that
the two phenomena are practically simultaneous.

There has also been a conflict of views as to the connexion between
magnetic and earth current disturbances. Airy's observations tended to
suggest that the earth current was the primary cause, and the magnetic
disturbance in considerable part at least its effect. Others, on the
contrary, have supposed earth currents to be a direct effect of changes
in the earth's magnetic field. The prevailing view now is that both the
magnetic and the earth current disturbances are due to electric currents
in the upper atmosphere, these upper currents becoming visible at times
as aurora.

9. There seems some evidence that earth currents can be called into
existence by purely local causes, notably difference of level. Thus K.A.
Brander (12) has observed a current flowing constantly for a good many
days from Airolo (height 1160 metres) to the Hospice St Gotthard (height
2094 metres). In an 8-km. line from Resina to the top of Vesuvius L.
Palmieri (13)--observing in 1889 at three-hour intervals from 9 A.M. to
9 P.M.--always found a current running uphill so long as the mountain
was quiet. On a long line from Vienna to Graz A. Baumgartner (14) found
that the current generally flowed from both ends towards intervening
higher ground during the day, but in the opposite directions at night.
During a fortnight in September and October 1885 hourly readings were
taken of the current in the telegraph cable from Fort-William to Ben
Nevis Observatory, and the results were discussed by H.N. Dickson (15),
who found a marked preponderance of currents up the line to the summit.
The recorded mean data, otherwise regarded, represent a "constant"
current, equal to 29 in the arbitrary units employed by Dickson, flowing
up the line, together with the following diurnal inequality, + denoting
current towards Fort-William (i.e. down the hill, and nearly east to
west).

  Hour |  1  |  2  |  3  |  4  |  5  | 6  |  7  |  8  |   9 |  10 |  11 |  12 |
       |     |     |     |     |     |    |     |     |     |     |     |     |
  A.M. | -21 | -41 | +13 | +23 | +55 | -3 | +25 | -32 | -59 | -62 | -46 |  +6 |
  P.M. | +24 | +18 |+115 | +18 | +75 | -5 | +50 |  -9 | -56 | -37 | -28 | -34 |

There is thus a diurnal inequality, which is by no means very irregular
considering the limited number of days, and it bears at least a general
resemblance to that shown by Weinstein's figures for an east-west line
in Germany. This will serve to illustrate the uncertainties affecting
these and analogous observations. A constant current in one direction
may arise in whole or part from plate E.M.F.'s; a current showing a
diurnal inequality will naturally arise between _any_ two places some
distance apart whether they be at different levels or not. Finally, when
records are taken only for a short time, doubts must arise as to the
generality of the results. During the Ben Nevis observations, for
instance, we are told that the summit was almost constantly enveloped in
fog or mist. By having three earth plates in the same vertical plane,
one at the top of a mountain, the others at opposite sides of it, and
then observing the currents between the summit and each of the base
stations, as well as directly between the base stations--during an
adequate number of days representative of different seasons of the year
and different climatic conditions--many uncertainties would soon be
removed.

10. _Artificial Currents._--The great extension in the applications of
electricity to lighting, traction and power transmission, characteristic
of the end of the 19th century, has led to the existence of large
artificial earth currents, which exert a disturbing influence on
galvanometers and magnetic instruments, and also tend to destroy metal
pipes. In the former case, whilst the disturbance is generally loosely
assigned to stray or "vagabond" earth currents, this is only partly
correct. The currents used for traction are large, and even if there
were a perfectly insulated return there would be a considerable
resultant magnetic field at distances from the track which were not
largely in excess of the distance apart of the direct and return
currents (16). At a distance of half a mile or more from an electric
tram line the disturbance is usually largest in magnetographs recording
the vertical component of the earth's field. The magnets are slightly
displaced from the position they would occupy if undisturbed, and are
kept in continuous oscillation whilst the trams are running (17). The
extent of the oscillation depends on the damping of the magnets.

The distance from an electric tram line where the disturbance ceases to
be felt varies with the system adopted. It also depends on the length of
the line and its subdivision into sections, on the strength of the
currents supplied, the amount of leakage, the absence or presence of
"boosters," and finally on the sensitiveness of the magnetic
instruments. At the U.S. Coast and Geodetic Survey's observatory at
Cheltenham the effect of the Washington electric trams has been detected
by highly sensitive magnetographs, though the nearest point of the line
is 12 m. away (18). Amongst the magnetic observatories which have
suffered severely from this cause are those at Toronto, Washington
(Naval Observatory), Kew, Paris (Parc St Maur), Perpignan, Nice, Lisbon,
Vienna, Rome, Bombay (Colaba) and Batavia. In some cases magnetic
observations have been wholly suspended, in others new observatories
have been built on more remote sites.

As regards damage to underground pipes, mainly gas and water pipes,
numerous observations have been made, especially in Germany and the
United States. When electric tramways have uninsulated returns, and the
potential of the rails is allowed to differ considerably from that of
the earth, very considerable currents are found in neighbouring pipes.
Under these conditions, if the joints between contiguous pipes forming a
main present appreciable resistance, whilst the surrounding earth
through moisture or any other cause is a fair conductor, current passes
locally from the pipes to the earth causing electrolytic corrosion of
the pipes. Owing to the diversity of interests concerned, the extent of
the damage thus caused has been very variously estimated. In some
instances it has been so considerable as to be the alleged cause of the
ultimate failure of water pipes to stand the pressure they are exposed
to.

  BIBLIOGRAPHY.--See Svante August Arrhenius, _Lehrbuch der kosmischen
  Physik_ (Leipzig, 1903), pp. 984-990. For lists of references see J.E.
  Burbank, _Terrestrial Magnetism_, vol. 10 (1905), p. 23, and P.
  Bachmetjew (8). For papers descriptive of corrosion of pipes, &c., by
  artificial currents see _Science Abstracts_ (in recent years in the
  volumes devoted to engineering) under the heading "Traction, Electric;
  Electrolysis." The following are the references in the text:--(1)
  _Phil. Trans. R.S._ for 1849, pt. i. p. 61; (2) _Phil. Trans. R.S._
  vol. 151 (1861), p. 89, and vol. 152 (1862), p. 203; (3) _Étude des
  courants telluriques_ (Paris, 1884); (4) _Die Erdströme im deutschen
  Reichstelegraphengebiet_ (Braunschweig, 1900); (5) _Phil. Trans. R.S._
  vol. 158 (1868), p. 465, and vol. 160 (1870), p. 215; (6) _Mém. de
  l'Académie St-Pétersbourg_, t. 31, No. 12 (1883); (7) T. Moureaux,
  _Ann. du Bureau Central Mét._ (Année 1893), 1 Mem. p. B 23; (8) P.
  Bachmetjew, _Mém. de l'Académie St-Pétersbourg_, vol. 12, No. 3
  (1901); (9) _Terrestrial Magnetism_, vol. 3 (1898), p. 130; (10)
  _Journal Tel. Engineers_ (1881); (11) _Proc. R.S._ vol. 52 (1892), p.
  191; (12) _Akad. Abhandlung_ (Helsingfors, 1888); (13) _Acad. Napoli
  Rend._ (1890), and _Atti_ (1894, 1895); (14) _Pogg. Ann._ vol. 76, p.
  135; (15) _Proc. R.S.E._ vol. 13, p. 530; (16) A. Rücker, _Phil. Mag._
  1 (1901), p. 423, and R.T. Glazebrook, ibid. p. 432; (17) J. Edler,
  _Elektrotech. Zeit._ vol. 20 (1899); (18) L.A. Bauer, _Terrestrial
  Magnetism_, vol. 11 (1906), p. 53.     (C. Ch.)



EARTH-NUT, the English name for a plant known botanically as _Conopodium
denudatum_ (or _Bunium flexuosum_), a member of the natural order
Umbelliferae, which has a brown tuber-like root-stock the size of a
chestnut. It grows in woods and fields, has a slender flexuous smooth
stem 2 to 3 ft. high, much-divided leaves, and small white flowers in
many-rayed terminal compound umbels. Boswell Syme, in _English Botany_,
iv. 114, says: "The common names of this plant in England are various.
It is known as earth-nut, pig-nut, ar-nut, kipper-nut, hawk-nut,
jar-nut, earth-chestnut and ground-nut. Though really excellent in taste
and unobjectionable as food, it is disregarded in England by all but
pigs and children, both of whom appreciate it and seek eagerly for it."
Dr Withering describes the roots as little inferior to chestnuts. In
Holland and elsewhere on the continent of Europe they are more
generally eaten.



EARTH PILLAR, a pillar of soft rock, or earth, capped by some harder
material that has protected it from denudation. The "bad lands" of
western North America furnish numerous examples. Here "the formations
are often beds of sandstone or shale alternating with unindurated beds
of clay. A semi-arid climate where the precipitation is much
concentrated seems to be most favourable to the development of this type
of formation." The country round the Dead Sea, where loose friable sandy
clay is capped by harder rock, produces "bad-land" topography. The cap
of hard rock gives way at the joints, and the water making its way
downwards washes away the softer material directly under the cracks,
which become wider, leaving isolated columns of clay capped with hard
sandstone or limestone. These become smaller and fewer as denudation
proceeds, the pillars standing a great height at times, until finally
they all disappear.



EARTHQUAKE. Although the terrible effects which often accompany
earthquakes have in all ages forced themselves upon the attention of
man, the exact investigation of seismic phenomena dates only from the
middle of the 19th century. A new science has been thus established
under the name of _seismology_ (Gr. [Greek: seismos], an earthquake).

_History._--Accounts of earthquakes are to be found scattered through
the writings of many ancient authors, but they are, for the most part,
of little value to the seismologist. There is a natural tendency to
exaggeration in describing such phenomena, sometimes indeed to the
extent of importing a supernatural element into the description. It is
true that attempts were made by some ancient writers on natural
philosophy to offer a rational explanation of earthquake phenomena, but
the hypotheses which their explanations involved are, as a rule, too
fanciful to be worth reproducing at the present day. It is therefore
unnecessary to dwell upon the references to seismic phenomena which have
come down to us in the writings of such historians and philosophers as
Thucydides, Aristotle and Strabo, Seneca, Livy and Pliny. Nor is much to
be gleaned from the pages of medieval and later writers on earthquakes,
of whom the most notable are Fromondi (1527), Maggio (1571) and
Travagini (1679). In England, the earliest work worthy of mention is
Robert Hooke's _Discourse on Earthquakes_, written in 1668, and read at
a later date before the Royal Society. This discourse, though containing
many passages of considerable merit, tended but little to a correct
interpretation of the phenomena in question. Equally unsatisfactory were
the attempts of Joseph Priestley and some other scientific writers of
the 18th century to connect the cause of earthquakes with electrical
phenomena. The great earthquake of Lisbon in 1755 led the Rev. John
Michell, professor of mineralogy at Cambridge, to turn his attention to
the subject; and in 1760 he published in the _Philosophical
Transactions_ a remarkable essay on the Cause and Phenomena of
Earthquakes. A suggestion of much scientific interest was made by Thomas
Young, when in his _Lectures on Natural Philosophy_, published in 1807,
he remarked that an earthquake "is probably propagated through the earth
nearly in the same manner as a noise is conveyed through the air." The
recognition of the fact that the seismologist has to deal with the
investigation of wave-motion in solids lies at the very base of his
science. In 1846 Robert Mallet communicated to the Royal Irish Academy
his first paper "On the Dynamics of Earthquakes"; and in the following
year W. Hopkins, of Cambridge, presented to the British Association a
valuable report in which earthquake phenomena were discussed in some
detail. Mallet's labours were continued for many years chiefly in the
form of Reports to the British Association, and culminated in his great
work on the Neapolitan earthquake of 1857. An entirely new impetus,
however, was given to the study of earthquakes by an energetic body of
observers in Japan, who commenced their investigations about the year
1880, mainly through the influence of Prof. John Milne, then of Tokyo.
Their work, carried on by means of new instruments of precision, and
since taken up by observers in many parts of the world, has so extended
our knowledge of earthquake-motion that seismology has now become
practically a new department of physical science.

It is hardly too much to say, however, that the earliest systematic
application of scientific principles to the study of the effects of an
earthquake was made by Mallet in his investigation of the Neapolitan
earthquake mentioned above. It is true, the great Calabrian earthquake
of 1783 had been the subject of careful inquiry by the Royal Academy of
Naples, as also by Deodat Dolomieu and some other scientific
authorities; but in consequence of the misconception which at that time
prevailed with regard to the nature of seismic activity, the results of
the inquiry, though in many ways interesting, were of very limited
scientific value. It was reserved for Mallet to undertake for the first
time an extensive series of systematic observations in an area of great
seismic disturbance, with the view of explaining the phenomena by the
application of the laws of wave-motion.


  Neapolitan earthquake, 1857.

The "Great Neapolitan Earthquake," by which more than 12,300 lives were
lost, was felt in greater or less degree over all Italy south of the
parallel of 42°, and has been regarded as ranking third in order of
severity among the recorded earthquakes of Europe. The principal shock
occurred at about 10 P.M. on the 16th of December 1857; but, as is
usually the case, it had been preceded by minor disturbances and was
followed by numerous after-shocks which continued for many months. Early
in 1858, aided by a grant from the Royal Society, Mallet visited the
devastated districts, and spent more than two months in studying the
effects of the catastrophe, especially examining, with the eye of an
engineer, the cracks and ruins of the buildings. His voluminous report
was published in 1862, and though his methods of research and his
deductions have in many cases been superseded by the advance of
knowledge, the report still remains a memorable work in the history of
seismology.

Much of Mallet's labour was directed to the determination of the
position and magnitude of the subterranean source from which the
vibratory impulses originated. This is known variously as the _seismic
centre_, _centrum_, _hypocentre_, _origin_ or _focus_. It is often
convenient to regard this centre theoretically as a point, but
practically it must be a locus or space of three dimensions, which in
different cases varies much in size and shape, and may be of great
magnitude. That part of the surface of the earth which is vertically
above the centre is called the _epicentre_; or, if of considerable area,
the epicentral or epifocal tract. A vertical line joining the epicentre
and the focus was termed by Mallet the _seismic vertical_. He calculated
that in the case of the Neapolitan earthquake the focal cavity was a
curved lamelliform fissure, having a length of about 10 m. and a height
of about 3½ m., whilst its width was inconsiderable. The central point
of this fissure, the theoretical seismic centre, he estimated to have
been at a depth of about 6½ m. from the surface. Dr C. Davison, in
discussing Mallet's data, was led to the conclusion that there were two
distinct foci, possibly situated on a fault, or plane of dislocation,
running in a north-west and south-east direction. Mallet located his
epicentre near the village of Caggiano, not far from Polla, while the
other seems to have been in the neighbourhood of Montemurro, about 25 m.
to the south-east.

The intensity, or violence, of an earthquake is greatest in or near the
epicentre, whence it decreases in all directions. A line drawn through
points of equal intensity forms a curve round the epicentre known as an
_isoseist_, an _isoseismal_ or an _isoseismic line_. If the intensity
declined equally in all directions the isoseismals would be circles, but
as this is rarely if ever the case in nature they usually become
ellipses and other closed curves. The tract which is most violently
shaken was termed by Mallet the _meizoseismic area_, whilst the line of
maximum destruction is known as the _meizoseismic line_. That isoseismal
along which the decline of energy is most rapid was called by K. von
Seebach a _pleistoseist_.

In order to determine the position of the seismic centre, Mallet made
much use of the cracks in damaged buildings, especially in walls of
masonry, holding that the direction of such fractures must generally be
at right angles to that in which the normal earthquake-wave reached
them. In this way he obtained the "angle of emergence" of the wave. He
also assumed that free-falling bodies would be overthrown and projected
in the direction of propagation of the wave, so that the epicentre might
immediately be found from the intersection of such directions. These
data are, however, subject to much error, especially through want of
homogeneity in the rocks, but Mallet's work was still of great value.


  Charleston earthquake, 1886.

A different method of ascertaining the depth of the focus was adopted by
Major C.E. Dutton in his investigation of the Charleston earthquake of
the 31st of August 1886 for the U.S. Geological Survey. This catastrophe
was heralded by shocks of greater or less severity a few days previously
at Summerville, a village 22 m. north-west of Charleston. The great
earthquake occurred at 9.51 P.M., standard time of the 75th meridian,
and in about 70 seconds almost every building in Charleston was more or
less seriously damaged, while many lives were lost. The epicentral tract
was mainly a forest region with but few buildings, and the principal
records of seismological value were afforded by the lines of railway
which traversed the disturbed area. In many places these rails were
flexured and dislocated. Numerous fissures opened in the ground, and
many of these discharged water, mixed sometimes with sand and silt,
which was thrown up in jets rising in some cases to a height of 20 ft.
Two epicentres were recognized--one near Woodstock station on the South
Carolina railway, and the other, being the centre of a much smaller
tract, about 14 m. south-west of the first and near the station of
Rantowles on the Charleston and Savannah line. Around these centres and
far away isoseismal lines were drawn, the relative intensity at
different places being roughly estimated by the effects of the
catastrophe on various structures and natural objects, or, where visible
records were wanting, by personal evidence, which is often vague and
variable. The Rossi-Forel scale was adopted. This is an arbitrary scale
formulated by Professor M.S. de Rossi, of Rome, and Dr F.A. Forel, of
Geneva, based mostly on the ordinary phenomena observed during an
earthquake, and consisting of ten degrees, of which the lowest is the
feeblest, viz. I. Microseismic shock; II. Extremely feeble shock; III.
Very feeble shock; IV. Feeble; V. Shock of moderate intensity; VI.
Fairly strong shock; VII. Strong shock; VIII. Very strong shock; IX.
Extremely strong shock; X. Shock of extreme intensity. Other
conventional scales, some being less detailed, have been drawn up by
observers in such earthquake-shaken countries as Italy and Japan. A
curve, or theoretical isoseismal, drawn through certain points where the
decline of intensity on receding from the epicentre seems to be greatest
was called by Dutton an "index-circle"; and it can be shown that the
radius of such a circle multiplied by the square root of 3 gives the
focal depth theoretically. In this way it was computed that in the
Charleston earthquake the origin under Woodstock must have had a depth
of about 12 m. and that near Rantowles a depth of nearly 8 m. The
determination of the index-circle presents much difficulty, and the
conclusions must be regarded as only approximate.

It is probable, according to R.D. Oldham, that local earthquakes may
originate in the "outer skin" of the earth, whilst a large world-shaking
earthquake takes its origin in the deeper part of the "crust," whence
such a disturbance is termed a _bathyseism_. Large earthquakes may have
very extended origins, with no definite centre, or with several foci.


  Great Indian earthquake, 1897.

The gigantic disaster known as the "Great Indian Earthquake," which
occurred on the 12th of June 1897, was the subject of careful
investigation by the Geological Survey of India and was described in
detail by the superintendent, R.D. Oldham. It is sometimes termed the
Assam earthquake, since it was in that province that the effects were
most severe, but the shocks were felt over a large part of India, and
indeed far beyond its boundaries. Much of the area which suffered most
disturbance was a wild country, sparsely populated, with but few
buildings of brick or stone from which the violence of the shocks could
be estimated. The epicentral tract was of great size, having an
estimated area of about 6000 sq. m., but the mischief was most severe in
the neighbourhood of Shillong, where the stonework of bridges, churches
and other buildings was absolutely levelled to the ground. After the
main disturbance, shocks of greater or less severity continued at
intervals for many weeks. It is supposed that this earthquake was
connected with movement of subterranean rock-masses of enormous
magnitude along a great thrust-plane, or series of such planes, having a
length of about 200 m. and a maximum breadth of not less than 50 m. It
is pointed out by Oldham that this may be compared for size with the
great Faille du Midi in Belgium, which is known to extend for a distance
of 120 m. The depth of the principal focus, though not actually capable
of determination, was probably less than 5 m. from the surface. From the
focus many secondary faults and fractures proceeded, some reaching the
surface of the ground. Enormous landslips accompanied the earthquake,
and as an indirect effect of these slides the form of the water-courses
became in certain cases modified. Permanent changes of level were also
observed.


  Kangra earthquake, 1905.

Eight years after the great Assam earthquake India was visited by
another earthquake, which, though less intense, resulted in the loss of
about 20,000 lives. This catastrophe is known as the Kangra earthquake,
since its centre seems to have been located in the Kangra valley, in the
north-west Himalaya. It occurred on the 4th of April 1905, and the first
great shocks were felt in the chief epifocal district at about 6.9 a.m.,
Madras time. Although the tract chiefly affected was around Kangra and
Dharmsala, there was a subordinate epifocal tract in Dehra Dun and the
neighbourhood of Mussoorie, whilst the effects of the earthquake
extended in slight measure to Lahore and other cities of the plain. It
is estimated that the earthquake was felt over an area of about
1,625,000 m. Immediately after the calamity a scientific examination of
its effects was made by the Geological Survey of India, and a report was
drawn up by the superintendent, C.S. Middlemiss.


  California earthquake, 1906.

The great earthquake, which, with the subsequent fire, wrought such
terrible destruction in and around San Francisco on the 18th of April
1906, was the most disastrous ever recorded in California. It occurred
between 10 and 15 minutes after 5 A.M., standard time of the 120th
meridian. The moment at which the disaster began and the duration of the
shock varied at different localities in the great area over which the
earthquake was felt. At San Francisco the main shock lasted rather more
than one minute.

According to the official Report, the earthquake was due to rupture and
movement along the plane of the San Andreas fault, one of a series which
runs for several hundred miles approximately in a N.W. and S.E.
direction near the coast line. Evidence of fresh movement along this
plane of dislocation was traced for a distance of 190 m. from San Juan
on the south to Point Arena on the north. There the trace of the fault
is lost beneath the sea, but either the same fault or another appears 75
m. to the north at Point Delgada. The belt of disturbed country is
notoriously unstable, and part of the fault had been known as the
"earthquake crack." The direction is marked by lines of straight cliffs,
long ponds and narrow depressions, forming a Rift, or old line of
seismic disturbance. According to Dr G.K. Gilbert the earthquake zone
has a length of 300 or 400 m. The principal displacement of rock, in
1906, was horizontal, amounting generally to about 10 ft. (maximum 21
ft.), but there was also locally a slight vertical movement, which
towards the north end of the fault reached 3 ft. Movement was traced for
a distance of about 270 m., and it is estimated that at least 175,000
sq. m. of country must have been disturbed. In estimating the intensity
of the earthquake in San Francisco a new scale was introduced by H.O.
Wood. The greatest structural damage occurred on soft alluvial soil and
"made ground." Most of the loss of property in San Francisco was due to
the terrible fire which followed the earthquake and was beyond control
owing to the destruction of the system of water-supply.

Immediately after the catastrophe a California Earthquake Investigation
Committee was appointed by the governor of the state; and the American
Association for the Advancement of Science afterwards instituted a
Seismological Committee. The elaborate Report of the State Investigation
Committee, by the chairman, Professor A.C. Lawson, was published in
1908.

On the 17th of August 1906 a disastrous earthquake occurred at
Valparaiso, and the year 1906 was marked generally by exceptional
seismic activity.

The Jamaica earthquake of the 14th of January 1907 appears to have
accompanied movement of rock along an east and west fracture or series
of fractures under the sea a few miles from the city of Kingston. The
statue of Queen Victoria at Kingston was turned upon its pedestal the
eighth of a revolution.


  Messina earthquake, 1908.

A terrible earthquake occurred in Calabria and Sicily on December 28,
1908, practically destroying Messina and Reggio. According to the
official returns the total loss of life was 77,283. Whilst the principal
centre seems to have been in the Strait of Messina, whence the
disturbance is generally known as the Messina earthquake, there were
independent centres in the Calabrian peninsula, a country which had been
visited by severe earthquakes not long previously, namely on September
8, 1905, and October 23, 1907. The principal shock of the great Messina
earthquake of 1908 occurred at 5.21 A.M. (4.21 Greenwich time), and had
a duration of from 30 to 40 seconds. Neither during nor immediately
before the catastrophe was there any special volcanic disturbance at
Etna or at Stromboli, but it is believed that there must have been
movement along a great plane of weakness in the neighbourhood of the
Strait of Messina, which has been studied by E. Cortese. The sea-floor
in the strait probably suffered great disturbance, resulting in the
remarkable movement of water observed on the coast. At first the sea
retired, and then a great wave rolled in, followed by others generally
of decreasing amplitude, though at Catania the second was said to have
been greater than the first. At Messina the height of the great wave was
2.70 metres, whilst at Ali and Giardini it reached 8.40 metres and at
San Alessio as much as 11.7 metres. At Malta the tide-gauge recorded a
wave of 0.91 metre. The depth of the chief earthquake-centre was
estimated by Dr E. Oddone at about 9 kilometres. The earthquake and
accompanying phenomena were studied also by Professor A. Riccò, Dr M.
Baratta and Professor G. Platania and by Dr F. Omori of Tokyo. After the
great disturbance, shocks continued to affect the region intermittently
for several months. In certain respects the earthquake of 1908 presented
much resemblance to the great Calabrian catastrophe of 1783.

It has been proposed by R.D. Oldham that the disturbance which causes
the fracture and permanent displacement of the rocks during an
earthquake should be called an "earthshake," leaving the term earthquake
especially for the vibratory motion. The movement of the earthquake is
molecular, whilst that of the earthshake is molar. Subsequently he
suggested the terms _mochleusis_ and _orchesis_ ([Greek: mochleuô], I
heave; [Greek: orcheomai], I dance), to denote respectively the molar
and the molecular movement, retaining the word earthquake for use in its
ordinary sense.

In most earthquakes the proximate cause is generally regarded as the
fracture and sudden movement of underground rock-masses. Disturbances of
this type are known as "tectonic" earthquakes, since they are connected
with the folding and faulting of the rocks of the earth's crust. They
indicate a relief of the strain to which the rock-masses are subjected
by mountain-making and other crustal movements, and they are
consequently apt to occur along the steep face of a table-land or the
margin of a continent with a great slope from land to sea. In many cases
the immediate seat of the originating impulse is located beneath the
sea, giving rise to submarine disturbances which have been called
"seaquakes." Much attention has been given to these suboceanic
disturbances by Professor E. Rudolph.

Professor J.H. Jeans has pointed out that the regions of the earth's
crust most affected by earthquakes lie on a great circle corresponding
with the equator of the slightly pear-shaped figure that he assigns to
the earth. This would represent a belt of weakness, subject to crushing,
from the tendency of the pear to pass into a spherical or spheroidal
form under the action of internal stresses. According to the comte de
Montessus de Ballore, the regions of maximum seismic instability appear
to be arranged on two great circles, inclined to each other at about
67°. These are the Circumpacific and Mediterranean zones.

Maps of the world, showing the origins of large earthquakes each year,
accompany the Annual Reports of the Seismological Committee of the
British Association, drawn up by Professor Milne. It is important to
note that Professor Milne has shown a relationship between
earthquake-frequency and the wandering of the earth's pole from its mean
position. Earthquakes seem to have been most frequent when the
displacement of the pole has been comparatively great, or when the
change in the direction of movement has been marked. Valuable earthquake
catalogues have been compiled at various times by Alexis Perrey, R. and
J.W. Mallet, John Milne, T. Oldham, C.W.C. Fuchs, F. de Montessus de
Ballore and others.


  British earthquakes.

Such earthquakes as are felt from time to time in Great Britain may
generally be traced to the formation of faults, or rather to incidents
in the growth of old faults. The East Anglian earthquake of the 22nd of
April 1884--the most disastrous that had occurred in the British Isles
for centuries--was investigated by Prof. R. Meldola and W. White on
behalf of the Essex Field Club. The shocks probably proceeded from two
foci--one near the villages of Peldon and Abberton, the other near
Wivenhoe and Rowhedge, in N.E. Essex. It is believed that the
superficial disturbance resulted from rupture of rocks along a deep
fault. An attempt has been made by H. Darwin, for the Seismological
Committee of the British Association, to detect and measure any gradual
movement of the strata along a fault, by observation at the Ridgeway
fault, near Upway, in Dorsetshire. Dr C. Davison in studying the
earthquakes which have originated in Britain since 1889 finds that
several have been "twins." A twin earthquake has two maxima of intensity
proceeding from two foci, whereas a double earthquake has its successive
impulses from what is practically a single focus. The Hereford
earthquake of December 1896, which resulted in great structural damage,
was a twin, having one epicentre near Hereford and the other near Ross.
Davison refers it to a slip along a fault-plane between the anticlinal
areas of Woolhope and May Hill; and according to the same authority the
Inverness earthquake of the 18th of September 1901 was referable to
movement along a fault between Loch Ness and Inverness. The South Wales
earthquake of June 27, 1906, was probably due to movement connected with
the Armorican system of folds, striking in an east and west direction.

It may be noted that when a slip occurs along a fault, the displacement
underground may be but slight and may die out before reaching the
surface, so that no scarp is formed. In connexion, however, with a
seismic disturbance of the first magnitude the superficial features may
be markedly affected. Thus, the great Japan earthquake of October
1891--known often as the Mino-Owari earthquake--was connected with the
formation or development of a fault which, according to Professor B.
Koto, was traced on the surface for a distance of nearly 50 m. and
presented in places a scarp with a vertical throw of as much as 20 ft.,
while probably the maximum displacement underground was very much
greater.

Although most earthquakes seem to be of tectonic type, there are some
which are evidently connected, directly or indirectly, with volcanic
activity (see VOLCANO). Such, it is commonly believed, were the
earthquakes which disturbed the Isle of Ischia in 1881 and 1883, and
were studied by Professor J. Johnston-Lavis and G. Mercalli. In addition
to the tectonic and volcanic types, there are occasional earthquakes of
minor importance which may be referred to the collapse of the roof of
caverns, or other falls of rock in underground cavities at no great
depth. According to Prof. T.J.J. See most earthquakes are due, directly
or indirectly, to the explosive action of ste by the leakage of
sea-water through the ocean floor.


  Earthquake waves.

Whatever the nature of the impulse which originates the earthquake, it
gives rise to a series of waves which are propagated through the earth's
substance and also superficially. In one kind, known as normal or
condensational waves, or waves of elastic compression, the particles
vibrate to and from the centre of disturbance, moving in the direction
in which the wave travels, and therefore in a way analogous to the
movement of air in a sound-wave. Associated with this type are other
waves termed transverse waves, or waves of elastic distortion, in which
the particles vibrate across or around the direction in which the wave
is propagated. The normal waves result from a temporary change of volume
in the medium; the transverse from a change of shape. The distance
through which an earth-particle moves from its mean position of rest,
whether radially or transversely, is called the amplitude of the wave;
whilst the double amplitude, or total distance of movement, to and fro
or up and down, like the distance from crest to trough of a water wave,
may be regarded as the range of the wave. The period of a wave is the
time required for the vibrating particle to complete an oscillation. As
the rocks of the earth's crust are very heterogeneous, the
earthquake-waves suffer refraction and reflection as they pass from one
rock to another differing in density and elasticity. In this way the
waves break up and become much modified in course of transmission, thus
introducing great complexity into the phenomena. It is known that the
normal waves travel more rapidly than the transverse.

Measurements of the surface speed at which earthquake-waves travel
require very accurate time-measurers, and these are not generally
available in earthquake-shaken regions. Observations during the
Charleston earthquake of 1886 were at that time of exceptional value,
since they were made over a large area where standard time was kept.
Lines drawn through places around the epicentre at which the shock
arrives at the same moment are called coseismal lines. The motion of the
wave is to be distinguished from the movement of the vibrating
particles. The velocity of the earth-particle is its rate of movement,
but this is constantly changing during the vibration, and the rate at
which the velocity changes is technically called the acceleration of the
particle.

Unfelt movements of the ground are registered in the earthquake records,
or seismograms, obtained by the delicate instruments used by modern
seismologists. From the study of the records of a great earthquake from
a distant source, sometimes termed a teleseismic disturbance, some
interesting inferences have been drawn with respect to the constitution
of the interior of the earth. The complete record shows two phases of
"preliminary tremors" preceding the principal waves. It is believed that
while the preliminary tremors pass through the body of the earth, the
principal waves travel along or parallel to the surface. Probably the
first phase represents condensational, and the second phase
distortional, waves. Professor Milne concludes from the speed of the
waves at different depths that materials having similar physical
properties to those at the surface may extend to a depth of about 30 m.,
below which they pass into a fairly homogeneous nucleus. From the
different rates of propagation of the precursors it has been inferred by
R.D. Oldham that below the outer crust, which is probably not everywhere
of the same thickness, the earth is of practically uniform character to
a depth of about six-tenths of the radius, but the remaining four-tenths
may represent a core differing physically and perhaps chemically from
the outer part. Oldham also suggests, from his study of oceanic and
continental wave-paths, that there is probably a difference in the
constitution of the earth beneath oceans and beneath continents.

The surface waves, which are waves of great length and long period and
are propagated to great distances with practically a constant velocity,
have been regarded as quasi-elastic gravitational waves. Further, in a
great earthquake the surface of the ground is sometimes visibly agitated
in the epifocal district by undulations which may be responsible for
severe superficial damage. (See also for elastic waves ELASTICITY, §
89.)

An old classification of earthquake-shocks, traces of which still linger
in popular nomenclature, described them as "undulatory," when the
movement of the ground was mainly in a horizontal direction;
"subsultory," when the motion was vertical, like the effect of a normal
wave at the epicentre; and "vorticose," when the movement was rotatory,
apparently due to successive impulses in varying directions.

The sounds which are associated with seismic phenomena, often described
as subterranean rumbling and roaring, are not without scientific
interest, and have been carefully studied by Davison. "Isacoustic lines"
are curves drawn through places where the sound is heard by the same
percentage of observers. The sound is always low and often inaudible to
many.

The refined instruments which are now used by seismologists for
determining the elements of earthquake motion and for recording
earthquakes from distant origins are described in the article
SEISMOMETER. These instruments were developed as a consequence of the
attention given in modern times to the study of earthquakes in the Far
East.     (F. W. R.*)


  Seismology in Japan.

Strange as it may appear, the advances that have been made in the study
of earthquakes and the world-wide interest shown in their phenomena were
initiated in work commenced in Japan. When the Japanese government,
desiring to adopt Western knowledge, invited to its shores bodies of men
to act as its instructors, the attention of the newcomers was naturally
attracted to the frequent shakings of the ground. Interest in these
phenomena increased more rapidly than their frequency, and at length it
was felt that something should be done for their systematic study. At
midnight on the 22nd of February 1880 movements more violent than usual
occurred; chimneys were shattered or rotated, tiles slid down from
roofs, and in the morning it was seen that Yokohama had the appearance
of a city that had suffered a bombardment. The excitement was intense,
and before the ruins had been removed a meeting was convened and the
Seismological Society of Japan established. The twenty volumes of
original papers published by this body summarize to a large extent the
results of the later study of seismology.[1]

The attention of the students of earthquakes in Japan was at first
directed almost entirely to seismometry or earthquake measurement. Forms
of apparatus which then existed, as for example the seismographs,
seismometers and seismoscopes of Mallet, Palmieri and others, were
subjected to trial; but inasmuch as they did little more than indicate
that an earthquake had taken place--the more elaborate forms recording
also the time of its occurrence--they were rapidly discarded, and
instruments were constructed to _measure_ earthquake motion. Slightly
modified types of the new instruments devised in Japan were adopted
throughout the Italian peninsula, and it is fair to say that the
seismometry developed in Japan revolutionized the seismometry of the
world. The records obtained from the new instruments increased our
knowledge of the character of earthquake motion, and the engineer and
the architect were placed in a position to construct so that the effects
of known movements could be minimized. It was no doubt the marked
success, both practical and scientific, attending these investigations
that led the Japanese government to establish a chair of seismology at
its university, to organize a system of nearly 1000 observing stations
throughout the country, and in 1893 to appoint a committee of scientific
and practical men to carry out investigations which might palliate the
effects of seismic disturbances. In the first year this committee
received a grant of £5000, and as liberal sums for the same purpose
appear from time to time in the parliamentary estimates, it may be
assumed that the work has been fraught with good results. In their
publications we find not only records of experiences and experiments in
Japan, but descriptions and comments upon earthquake effects in other
countries. In two of the volumes there are long and extremely well
illustrated accounts of the earthquake which on the 12th of June 1897
devastated Assam, to which country two members of the above-mentioned
committee were despatched to gather such information as might be of
value to the architect and builder in earthquake-shaken districts.


  Seismological research.

A great impetus to seismological investigation in Europe and America was
no doubt given by the realization of the fact that a large earthquake
originating in any one part of the world may be recorded in almost any
other. Italy for many years past has had its observatories for recording
earthquakes which can be felt, and which are of local origin, but at the
present time at all its first-class stations we find instruments to
record the unfelt movements due to earthquakes originating at great
distances, and as much attention is now paid to the large earthquakes of
the world as to the smaller ones originating within Italian
territory.[2] The _Kaiserliche Akademie der Wissenschaften_ of Vienna
established earthquake observatories in Austria,[3] and the Central
Observatorium of St Petersburg has carried out similar work in Russia.
Germany attached a seismological observatory to its university at
Strassburg, whilst provision has been made for a professorship of Earth
Physics (_Geophysik_) at Göttingen.[4] In accordance with the
recommendation of the British Association, seismographs of a similar
character have been installed at stations all over the world.[5] The
principal objects of this extended and still extending system of
stations are to determine the velocity with which motion is propagated
over the surface and through the interior of the earth, to locate the
positions of sub-oceanic earthquake origins, and generally to extend our
knowledge respecting the physical nature of the planet on which we live.


  Frequency of earthquakes.

We now know that earthquakes are many times more frequent than was
previously supposed. In Japan, for example, between 1885 and 1892 no
fewer than 8331 were recorded--that is to say, on the average there were
during that time more than 1000 disturbances per year. Although many of
these did not cause a sensible shaking over areas exceeding a few
hundred square miles, many of them were sufficiently intense to
propagate vibrations round and through the globe. If we pick out the
well-marked earthquake districts of the world, and give to each of them
a seismicity or earthquake frequency per unit area one-third of that in
Japan, the conclusion arrived at is that considerable areas of our
planet are on the average shaken every half-hour.


  Volcanoes and earthquakes.

The knowledge which we now possess respecting the localities where
earthquakes are frequent and the forms of the foci from which they have
spread, enables us to speak definitely respecting the originating causes
of many of these phenomena. It is found, for example, that although in
many countries there may be displays of volcanic and seismic activity
taking place almost side by side, it is only rarely that there is direct
relationship between the two. Now and then, however, before a volcano
breaks into eruption there may be a few ineffectual efforts to form a
vent, each of which is accompanied by no more than a slight local
shaking of the ground. This is true even for the largest and most
violent eruptions, when mountains have with practically a single effort
blown off their heads and shoulders. Thus the earthquake which
accompanied the eruption of Bandaisan, in central Japan, in 1888 was
felt only over a radius of 25 m. The analyses of the seismic registers
of Japan clearly indicate that comparatively few shakings originate near
to the volcanoes of the country, the majority of them, like those of
many other countries, coming from regions where volcanic rocks are
absent. The greatest number spread inland from the Pacific seaboard, the
movement becoming more and more feeble as it approaches the backbone of
the country, which is drilled with numerous volcanic vents. What is true
for Japan is generally true for the western coasts of North and South
America.


  Origin of earthquakes.

Speaking broadly, earthquakes are most frequent along the steeper
flexures in the earth's surface, and in those regions where there is
geological evidence to show that slow secular movements in the earth's
crust are possibly yet in progress. With a unit distance of 2 degrees,
or 120 geographical m., we find that the slopes running eastwards from
the highlands of Japan and westwards from the Andean ridges down into
the Pacific vary from 1 in 20 to 1 in 30, and it is on the faces or near
to the bottom of these slopes that seismic efforts are frequent. The
slopes running from Australia, eastern America and western Europe into
the neighbouring oceans vary between 1 in 70 and 1 in 250, and in these
regions earthquakes are of rare occurrence. The seismic activity met
with in the Himalayas and the Alps finds its best explanation in the
fact that these mountains are geologically recent, and there are no
reasons to doubt that the forces which brought their folds into
existence are yet in action.

This peculiar association of earthquakes with pronounced topographical
configuration and certain geological conditions evidently indicates that
the origin of many of them is connected with rock folding. Inasmuch as
certain large earthquakes have been accompanied by rock fracture, as for
example in 1891, when in central Japan a fault some 50 m. in length was
created, whilst the origins of others have been distinctly traced to the
line of an existing fault or its continuation, we may conclude that the
majority of earthquakes are spasmodic accelerations in the secular
movements which are creating (and in some instances possibly
obliterating) the more prominent features of the earth's surface. These
secular movements, which include upheavals, subsidences, horizontal
displacements--all of which are explained on the assumption of a crust
seeking support on a nucleus gradually contracting by loss of heat, are
collectively referred to as bradyseismical ([Greek: bradys], slow)
movements. To these may be added movements directly attributable to the
influence of gravity. Sub-oceanic districts in a state of seismic strain
may be so far loaded by the accumulation of sediments that gentle
bending may be accompanied by sudden yieldings. This possibly accounts
for the frequency of earthquakes off the mouth of the Tonegawa on the
eastern side of Japan. The distortions so frequently observed in fossils
and pebbles, the varying thickness of contorted strata, and the "creep"
in coal-mines, together with other phenomena, indicate that rocks may
flow. Observations of this nature lead to the supposition that high
plateau-like regions may be gradually subsiding under the influence of
their own weight, and that the process of settlement may from time to
time be spasmodic in its character. Whether the earthquakes which
originate round the submerged basal frontiers of the continents bounding
the Pacific are ever attributable to such activities, it is impossible
to say. All that we know with certainty is that they are sometimes
accompanied by such a vast displacement of material that the ocean has
been set into a state of oscillation for periods of 24 hours, that in
some instances there have been marked changes in depth, and that
enormous sub-oceanic landslips have occurred. These phenomena are,
however, equally well explained on the assumption of sudden faulting
accompanied by violent shaking, which would dislodge steeply inclined
beds of material beneath the ocean as it does upon the land.


  Two types of earthquake motion.

Although the proximate cause of earthquake motion is traced to sudden
yieldings in the crust of the earth brought about by some form of
bradyseismical action, the existence of at least two distinct types of
seismic motion indicates that the mechanical conditions accompanying the
fracturing of rocks are not always identical. 90 or 95% of the
earthquakes which can be recorded consist of elastic or quasi-elastic
vibrations. The remainder, including the large earthquakes, not only
exhibit the elastic movements, but are accompanied by surface
undulations which are propagated most certainly for some hundreds of
miles round their origin, and then as horizontal movements sweep over
the whole surface of the globe. The former of these may accompany the
formation of a new fault or the sudden renewal of movement along an old
one; they are cracking or rending effects, without any great
displacement. The latter are probably fracturings accompanied by
vertical and horizontal displacements of masses of the earth's crust
sufficiently great to set up the observed surface undulations. These
shocks are so frequently followed a few minutes later by disturbances,
which from their similarity to the movements which have preceded them
may be called earthquake echoes, that we are led to the speculation that
we are here dealing with the caving-in of ill-supported portions of the
earth's crust, the waves from which are radiated to boundaries and then
returned to their origin to coalesce and give rise to a second impulse
not unlike the primary. Succeeding the first repetition of motion
recorded by the seismograph there is often a rhythmical repetition of
similar wave groups, suggesting the existence within our earth of
phenomena akin to multiple echoes.


  Character of earthquake motion.

The introduction of new methods into seismometry quickly revolutionized
our ideas respecting the character of earthquake motion. Although an
earthquake may be strongly felt within a distance of 50 m. from its
origin, and although the movements in the upper storeys of buildings
within the shaken area may be large, the actual range of the horizontal
motion of the ground is usually less than {1/10} of an inch. With such
earthquakes ordinary seismographs for recording vertical motion do not
show any disturbance. When the movement reaches ½ in. it becomes
dangerous, and a back-and-forth movement of an inch is usually
accompanied by destructive effects. In this latter case the amplitude of
the vertical record which indicates the existence of surface waves will
vary between ½ and {1/100} of an inch. In the earthquake which
devastated central Japan on the 26th of October 1891, nearly every
building within the epifocal district fell, the ground was fissured,
forests slipped down from mountain sides to dam up valleys, whilst the
valleys themselves were permanently compressed. The horizontal movements
seem to have reached 9 in. or 1 ft., and the surface undulations were
visible to the eye.


  Period and duration.

The rapidity with which the movements are performed varies throughout a
disturbance. A typical earthquake usually commences with minute elastic
vibrations, the periods of which vary between {1/5} and {1/20} of a
second. These are recorded by seismographs, and are noticed by certain
of the lower animals like pheasants, which before the occurrence of
movement perceptible to human beings scream as if alarmed. When an
earthquake is preceded by a sound we have evidence of preliminary
tremors even more rapid than those recorded by seismographs. Following
these precursors there is a shock or shocks, the period of which will be
1 or 2 seconds. From this climax the movements, although irregular in
character, become slower and smaller until finally they are
imperceptible. The duration of a small earthquake usually varies from a
few seconds to a minute, but large earthquakes, which are accompanied by
surface undulations, may be felt for 2 or 3 minutes, whilst an ordinary
seismograph indicates a duration of from 6 to 12 minutes. A free
horizontal pendulum tells us that with severe earthquakes the ground
comes to rest by a series of more or less rhythmical surgings,
continuing over 1 or 2 hours. Although the maximum displacement has a
definite direction, the successive vibrations are frequently performed
in many different azimuths. The predominating direction at a given
station in certain instances is apparently at right angles to the strike
of the neighbouring strata, this being the direction of easiest
yielding.


  Velocity.

Earthquake motion as recorded at stations several thousands of miles
distant from its origin exhibits characteristics strikingly different
from those just described. The precursors now show periods of from 1 to
5 seconds, whilst the largest movements corresponding to the shocks may
have periods of from 20 to 40 seconds. The interval of time by which the
first tremors have outraced the maximum movement has also become
greater. Within a few hundreds of miles from an origin this interval
increases steadily, the velocity of propagation of the first movements
being about 2 km. per second, whilst that of the latter may be taken at
about 1.6 km. per second. Beyond this distance the velocity of
transmission of the first movements rapidly increases, and for great
distances, as for example from Japan to England, it is higher than we
should expect for waves of compression passing through steel or glass.
This observation precludes the idea that these preliminary tremors have
travelled through the heterogeneous crust of the earth, and since the
average velocity of their transmission increases with the length of the
path along which they have travelled, and we but rarely obtain certain
evidence that a seismograph has been disturbed by waves which have
reached it by travelling in opposite directions round the world, we are
led to the conclusion that earthquake precursors pass through our earth
and not round its surface. The following table relating to earthquakes,
which originated off the coast of Borneo on the 20th and 27th of
September 1897, is illustrative of the velocities here considered:--

  +---------------------------+-----------+-------------+---------------+
  |                           |           |             |       _______ |
  |                           | Distance  |  Velocity   |      /Average |
  |        Localities         |   from    |   in kms.   |     /depth of |
  |                           |  origin   | per sec. if |  \ / chord in |
  |                           |in degrees.|  on chord.  | ¼ V  kms.     |
  +---------------------------+-----------+-------------+---------------+
  | Nicolaieff                |    81°    |     8.1     |      8.0      |
  | Potsdam                   |    92°    |     8.4     |      9.1      |
  | Catania, Ischia, Rocca di |           |             |               |
  |   Papa, Rome              |    96°    |     9.0     |      9.5      |
  | Isle of Wight             |   103°    |     9.8     |     10.2      |
  +---------------------------+-----------+-------------+---------------+

The chords referred to here are those joining the earthquake origins and
distant observing stations, and it will be noted that one-quarter of the
square root of the average depths at which these run closely corresponds
to observed average velocities if wave paths followed chords. This
increase of velocity with average depth shows that the paths followed
through the earth must be curved with their convexity towards the centre
of the earth. These observations do not directly tell us to what extent
a true wave path is deflected from the direction of a chord, but they
suggest as an extremely plausible assumption that the square of the
speed is a linear function of the depth below the surface of the earth.
With this assumption Dr C.G. Knott shows that the square of the speed
(v²) can be expressed linearly in terms of the average depth of the
chord d, thus: v² = 2.9 + .026 d, the units being miles and seconds. The
formula applies with fair accuracy to moderate and high values of d, but
it gives too high a value for short chords. It follows that the square
of the speed increases 0.9% per mile of descent in the earth. The
conclusion we arrive at is that the preliminary tremors which pass
through the earth do so in the vicinity of their origin at the rate of
almost 2.3 km. per second. This velocity increases as the wave path
plunges downwards, attaining in the central regions a velocity of 16 to
17 kms., whilst the highest average velocity which is across a diameter
lies between 10 and 12 kms. per second.

The large surface waves radiating from an origin to a distant place have
velocities lying between 1.6 and 4 kms. per second, and it has been
observed that when the higher velocity has been noted this refers to an
observation at a station very remote from the origin. One explanation of
this is the assumption that only very large waves indicating a large
initial disturbance are capable of travelling to great distances, and as
pointed out by R.D. Oldham, large waves under the influence of gravity
will travel faster than small waves. These waves (which may be
gravitational or distortional) are recorded as slow tiltings of the
ground measured by angles of 0.5 to 10 or 15 seconds of arc, or as
horizontal displacements of 0.5 or several millimetres. Their calculated
lengths have reached 50 kms. (31 m.).


  Frequency.

In the section of this article relating to the cause of earthquakes a
little has been said about their frequency or the number of times these
phenomena are repeated during a given interval of time. It has been
shown that all countries are very often moved by earthquakes which have
originated at great distances. Great Britain, for example, is crossed
about 100 times a year by earthquake waves having durations of from 3
minutes to 3 hours, whilst the vibratory motions which originate in that
country are not only small but of rare occurrence. In the earlier stages
of the world's history, because the contraction of its nucleus was more
rapid than it is at present, it is commonly inferred that phenomena
accompanying bradyseismical activity must have been more pronounced and
have shown themselves upon a grander scale than they do at the present
time. Now, although the records of our rocks only carry us back over a
certain portion of this history, they certainly represent an interval of
time sufficiently long to furnish some evidence of such enfeeblement if
it ever existed. So far from this being the case, however, we meet with
distinct evidences in the later chapters of geological history of
plutonic awakenings much more violent than those recorded at its
commencement. During Palaeozoic times many mountain ranges were formed,
and accompanying these orogenic processes there was marked volcanic
activity. In the succeeding Secondary period plutonic forces were
quiescent, but during the formation of the early Tertiaries, when some
of the largest mountain ranges were created, they awoke with a vigour
greater than had ever been previously exhibited. At this period it is
not improbable that Scotland was as remarkable for its volcanoes and its
earthquakes as Japan is at the present day. If the statement relating to
the general decrease in bradyseismical changes referred merely to their
frequency, and omitted reference to their magnitude, the views of the
geologist and physicist might harmonize. One explanation for this
divergence of opinion may rest on the fact that too little attention has
been directed to all the conditions which accompany the adaptation of
the earth's crust to its shrinking nucleus. As the latter grows smaller
the puckerings and foldings of the former should grow larger. Each
succeeding geological epoch should be characterized by mountain
formations more stupendous than those which preceded them, whilst the
fracturing, dislocation, caving-in of ill-supported regions, and
creation of lines of freedom for the exhibition of volcanic activity
which would accompany these changes, would grow in magnitude. The
written records of many countries reflect but on a smaller scale the
crystallized records in their hills. In 1844, at Comrie, in Perthshire,
as many as twelve earthquakes were recorded in a single month, whilst
now there are but one or two per year. Earthquake frequency varies with
time. A district under the influence of hypogenic activities reaches a
condition of seismic strain which usually is relieved rapidly at first,
but subsequently more slowly.

The small shocks which follow an initial large disturbance are known as
after-shocks. The first shock which in 1891 devastated central Japan was
accompanied by the formation of a large fault, and the 3364 small shocks
which succeeded this during the following two years are regarded as due
to intermittent settlements of disjointed material. The decreasing
frequency with which after-shocks occur may be represented by a curve.
Dr F. Omori points out that the continuation of such a curve gives the
means of determining the length of time which will probably elapse
before the region to which it refers will return to the same seismic
quiescence that it had prior to the initial disturbance.


  Periodicity.

The positive results that we have respecting the periodicity of
earthquakes are but few. Generally earthquakes are somewhat more
frequent during winter than during summer, and this applies to both the
northern and southern hemispheres. The annual periodicity, which,
however, does not show itself if only destructive earthquakes are
considered, finds an explanation, according to Dr Knott, in the annual
periodicity of long-continued stresses, as for example those due to the
accumulation of snow and to barometric gradients. For certain earthquake
regions there appears to be a distinct semi-annual period for which no
satisfactory explanation has yet been adduced. Although the elaborate
registers of Japan, which have enabled us to group earthquakes according
to their respective origins and varying intensities, and to separate
after-shocks from initial disturbances, have been subjected by Dr Knott
to most careful analysis, with the object of discovering periodicities
connected with the ebb and flow of the tides, the lunar day or lunar
months, nothing of marked character has been found. Certainly there is
slight evidence of a periodicity connected with the times of conjunction
and opposition of the sun and moon, and a maximum frequency near the
time of perigee, but the effect of lunar stresses is comparatively
insignificant. Ordinary earthquakes, and especially after-shocks, show a
diurnal period, but we cannot say that there are more earthquakes during
the night than during the day.


  Magnetic phenomena.

Many experiments and investigations have been made to determine a
possible relationship between earthquakes and electrical phenomena, but
beyond drawing attention to the fact that luminous appearances may
accompany the friction of moving masses of rock, and that a temporary
current may be established in a line by the disturbance of an
earth-plate, these inquiries have yielded but little of importance. The
inquiries respecting a possible relationship between adjustments so
frequently taking place within and beneath that region called the crust
of the earth and magnetic phenomena are, however, of a more promising
nature. We have seen that at or near the origin of earthquakes which for
several hours disturb continents, and occasionally cause oceans to
oscillate for longer periods, we sometimes have direct evidence of the
bodily displacement of many cubic miles of material. When this material
is volcanic it is almost invariably magnetic, and we perceive in its
sudden rearrangement causes which should produce magnetic effects within
an epifocal district. In Japan, where attention is being directed to
phenomena of this description, not only have such effects been observed,
but unusual magnetic disturbances have been noted prior to the
occurrence of large earthquakes. These may, of course, be regarded as
mere coincidences, but when we consider volcanic and seismic activities
as evidences of physical and chemical changes, together with mechanical
displacements of a magnetic magma, it is reasonable to suppose that they
should have at least a local influence upon magnetic needles. Another
form of disturbance to which magnetic needles are subjected is that
which accompanies the passage of large earth-waves beneath certain
observatories situated at great distances from earthquake origins. At
Utrecht, Potsdam and Wilhelmshaven the magnetographs are frequently
disturbed by seismic waves, whilst at many other European observatories
such effects are absent or only barely appreciable. To explain these
marked differences in the behaviour of magnetic needles at different
stations we are at present only in a position to formulate hypotheses.
They may be due to the fact that different needles have different
periodic times of oscillation; it is possible that at one observatory
the mechanical movements of the ground are much greater than at others;
we may speculate on the existence of materials beneath and around
various observatories which are different in their magnetic characters;
and, lastly, we may picture a crust of varying thickness, which from
time to time is caused to rise and fall upon a magnetic magma, the
places nearest to this being the most disturbed.


  Effects on the human mind.

A subject to which but little attention has been directed is the effect
which displays of seismic and volcanic activities have had upon the
human mind. The effects are distinctly dual and opposite in character.
In countries like England, where earthquakes are seldom experienced, the
prevailing idea is that they are associated with all that is baneful.
For certain earthquakes, which fortunately are less than 1% of those
which are annually recorded, this is partially true. A disastrous shock
may unnerve a whole community. Effects of this nature, however, differ
in a marked manner with different nationalities. After the shock of
1891, when Japan lost 9960 of its inhabitants, amongst the wounded
indications of mental excitement were shown in spinal and other trouble.
Notwithstanding the lightheartedness of this particular nation, it is
difficult to imagine that the long series of seismic effects chronicled
in Japanese history, which culminated in 1896 in the loss of 29,000
lives by sea-waves, has been without some effect upon its mental and
moral character. Several earthquakes are annually commemorated by
special services at temples. In bygone times governments have recognized
earthquakes as visitations of an angry deity, whom they have endeavoured
to appease by repealing stringent laws and taxes. In other countries the
sermons which have been preached to show that the tremblings of the
world were visitations consequent on impiety, and the prayers which have
been formulated to ward off disasters in the future, far exceed in
number the earthquakes which gave rise to them. In 1755 many of the
English clergy held the view that Lisbon was destroyed because its
inhabitants were Catholics, whilst the survivors from that disaster
attributed their misfortune to the fact that they had tolerated a few
Protestant heretics in their midst. To avoid a recurrence of disaster
certain of these were baptized by force. In the myths relating to
underground monsters and personages that are said to be the cause of
earthquakes we see the direct effects which exhibitions of seismic and
volcanic activity have produced upon the imagination. The beliefs, or
more properly, perhaps, the poetical fancies, thus engendered have
exhibited themselves in various forms. Beneath Japan there is said to be
a catfish, which in other countries is replaced by a mole, a hog, an
elephant or other living creature, which when it is restless shakes the
globe. The Kamchadales picture a subterranean deity called Tuil, who in
Scandinavian mythology is represented by the evil genius Loki. We have
only to think of the reference in the Decalogue forbidding the making of
graven images of that which is in the earth beneath, to see in early
Biblical history evidence of a subterranean mythology; and it seems
probable that the same causes which led to the creation of Pluto, Vulcan
and Poseidon gave rise to practices condemned by Moses.


  Building to withstand earthquakes.

Perhaps the greatest practical benefits derived from seismological
investigations relate to important changes and new principles which have
been introduced into the arts of the engineer and builder when
constructing in earthquake countries. The new rules and formulae, rather
than being theoretical deductions from hypotheses, are the outcome of
observation and experiment. True measures of earthquake motion have been
given to us by modern seismometers, with the result that seismic
destructivity can be accurately expressed in mechanical units. From
observation we now know the greatest acceleration and maximum velocity
of an earth particle likely to be encountered; and these are measures of
the destructivity. The engineer is therefore dealing with known forces,
and he has to bear in mind that these are chiefly applied in a
horizontal direction. A formula connecting the acceleration requisite to
overturn bodies of different dimensions has been given. The acceleration
which will fracture or shatter a column firmly fixed at its foundation
to the moving earth may be expressed as follows:--

      1  gFAB
  a = -- ----,
      6   fw

where

  a = the acceleration per sec. per sec.
  F = the force of cohesion, or force per unit surface, which when
        gradually applied produces fracture.
  A = area of base fractured.
  B = thickness of the column.
  f = height of centre of gravity of column above the fractured base.
  w = the weight of the portion broken off.

With this formula and its derivatives we are enabled to state the height
to which a wall, for example, may be built capable of resisting any
assumed acceleration. Experience has shown that yielding first shows
itself at the base of a pier, a wall or a building, and it is therefore
clear that the lower portion of such structures should be of greater
dimensions or stronger than that above. Piers having these increased
dimensions below, and tapering upwards in a proper manner, so that every
horizontal section is sufficiently strong to resist the effects of the
inertia of its superstructure, are employed to carry railways in Japan.
In that country cast-iron piers are things of the past, whilst piers of
masonry, together with their foundations, no longer follow the rules of
ordinary engineering practice.

After flood, fire, earthquake, or when opportunity presents itself,
changes are introduced in the construction of ordinary buildings. In a
so-called earthquake-proof house, although externally it is similar to
other dwellings, we find rafters running from the ridge pole to the
floor sills, an exceedingly light roof, iron straps and sockets
replacing mortices and tenons, and many other departures from ordinary
rules. Masonry arches for bridges or arched openings in walls (unless
protected by lintels), heavy gables, ornamental copings, cappings for
chimneys, have by their repeated failure shown that they are undesirable
features for construction in earthquake countries. As sites for
buildings it is well to avoid soft ground, on which the movement is
always greater than on hard ground. Excessive movement also takes place
along the face of unsupported openings, and for this reason the edges of
scarps, bluffs, cuttings and river-banks are localities to be avoided.
In short, the rules and precautions which have to be recognized so as to
avoid or mitigate the effects of earthquake movement are so numerous
that students of engineering and architecture in Japan receive a special
course of lectures on this subject. When it is remembered that a large
earthquake may entail a loss of life greater than that which takes place
in many wars, and that for the reconstruction of ordinary buildings,
factories and public works an expenditure of several million pounds
sterling is required, the importance of these studies cannot be
overrated. Severe earthquakes are fortunately unknown in the British
Isles, but we have simply to turn our eyes to earthquake-shaken colonies
and lands in close commercial touch with Great Britain to realize the
importance of mitigating such disasters as much as possible, and any
endeavour to obviate the wholesale destruction of life should appeal to
the civilized communities of the world.


  Applications of seismometry.

An unexpected application of seismometry has been to record the
vibration of railway trains, bridges and steamships. An instrument of
suitable construction will give records of the more or less violent
jolting and vibratory movements of a train, and so localize
irregularities due to changes in the character of ballast and sleepers,
to variation in gauge, &c. An instrument placed on a locomotive throws
considerable light upon the effects due to the methods of balancing the
wheels, and by alterations in this respect a saving of fuel of from 1 to
5 lb. of coal per mile per locomotive has sometimes been effected.

By mapping the centres from which earthquakes originate off the coast of
Japan, we have not only determined districts where geological activity
is pronounced, but have placed before the cable engineer well-defined
localities which it is advisable to avoid; and in the records of unfelt
earthquakes which originate far from land similar information is being
collected for the deeper parts of the oceans. Occasionally these records
have almost immediately made clear the cause of a cable failure. From
lack of such information in 1888, when the cables connecting Australia
with the outer world were simultaneously broken, the sudden isolation
was regarded as a possible operation of war, and the colonists called
out their naval and military reserves. Records of earthquakes
originating at great distances have also frequently enabled us to
anticipate, to correct, to extend, or to disprove telegraphic accounts
of the disasters. Whatever information a seismogram may give is certain,
whilst the information gathered from telegrams may in the process of
transit become exaggerated or minimized. Otherwise unaccountable
disturbances in records from magnetographs, barographs and other
instruments employed in observatories are frequently explained by
reference to the traces yielded by seismometers. Perhaps the greatest
triumph in seismological investigation has been the determination of the
varying rates at which motion is propagated through the world. These
measurements have already thrown new light upon its effective rigidity,
and if we assume that the density of the earth increases uniformly from
its surface towards its centre, so that its mean density is 5.5, then,
according to Knott, the coefficient of elasticity which governs the
transmission of preliminary tremors of an earthquake increases at a rate
of nearly 1.2% per mile of descent.     (J. Mi.)

  AUTHORITIES.--J. Milne, _Seismology_ (London, 1898), _Earthquakes_
  (London, 1898), Bakerian Lecture, "Recent Advances in Seismology,"
  _Proc. Roy. Soc._, 1906, 77, p. 365; J.A. Ewing, _Memoir on Earthquake
  Measurement_ (Tokyo, 1883); C.E. Dutton, _Earthquakes in the Light of
  the New Seismology_ (London, 1904); "The Charleston Earthquake of Aug.
  31, 1886," Ninth Annual _Report_ of the United States Geological
  Survey, 1889; W.H. Hobbs, _Earthquakes, an Introduction to Seismic
  Geology_ (London, 1908), "The San Francisco Earthquake and Fire,
  1906," _Bull. U.S. Geol. Surv._ No. 324; "The California Earthquake of
  Ap. 18, 1906," _Rep. State Earthq. Com._ (Washington, D.C., 1908);
  R.D. Oldham, "Report on the Great Earthquake of 12 June 1897," _Mem.
  Geol. Surv. India_, xxix. 1899, "On the Propagation of Earthquake
  Motion to great Distances," _Phil. Trans._, 1900, A, vol. 194, p. 135,
  "The Constitution of the Interior of the Earth as revealed by
  Earthquakes," _Quar. Jour. Geol. Soc._, 1906, 62, p. 456; 1907, 63, p.
  344; C. Davison, _A Study of Recent Earthquakes_ (London, 1905); _The
  Hereford Earthquake of December 17, 1896_ (Birmingham, 1899), "The
  Investigation of Earthquakes," _Beiträge z. Geophysik_, Bd. ix., 1908,
  p. 201, and papers on British earthquakes in _Quart. Jour. Geol.
  Soc._; T.J.J. See, "The Cause of Earthquakes, Mountain Formation and
  Kindred Phenomena connected with the Physics of the Earth," _Proc.
  Amer. Phil. Soc._, 1906, 45, p. 273; F. Frech, "Erdbeben und
  Gebirgsbau," _Petermann's Mitteilungen_, Bd. 53, 1907, p. 245 (with
  maps); C.G. Knott, _The Physics of Earthquake Phenomena_ (Oxford,
  1908); Comte F. de Montessus de Ballore, _Les Tremblements de terre:
  géographie séismologique_ (Paris, 1906), _La Science séismologique_
  (1907); _Transactions of the Seismological Society of Japan;
  Seismological Journal_ (Yokohama); _Bollettino della Società
  Sismologica Italiana_ (Rome); _Reports of the British Association_,
  containing the annual reports of the Committee for Seismological
  Investigations; papers in the _Beiträge zur Geophysik_ and the
  _Ergänzungsbände_.


FOOTNOTES:

  [1] The publications for 1880-1892 were termed the _Transactions of
    the Seismological Society of Japan_, and for 1893-1895 the
    _Seismological Journal of Japan_. The observations are now published
    by the Earthquake Investigation Committee of Japan, and edited by F.
    Omori, professor of seismology at the university of Tokyo.

  [2] The chief Italian station is at Rocca di Papa near Rome. It is
    equipped with delicate instruments designed by its director, Giovanni
    Agamennone. The records since 1895 are published in the _Bollettino
    della Società Sismologica Italiana_, edited by Luigi Palazzo,
    director of the Central Office for Meteorology and Geodynamics at
    Rome.

  [3] The chief Austrian publications are:--_Mittheilungen der
    Erdbebencommission der k. Akad. der Wissen. in Wien_ (since 1897);
    _Die Erdbebenwarte_ (1901-1907); and the "Neueste
    Erdbebennachrichten, _Beilage der Monatsschrift Die Erdbebenwarte_."

  [4] The "International Seismological Association" was founded at
    Strassburg in 1903, and publishes the _Beiträge zur Geophysik_,
    edited by George Gerland, director of the Strassburg station; the
    papers are printed in several languages.

  [5] The records of the British Association stations are published
    (since 1896) in the _Reports_. Chile has a national earthquake
    service (founded after the Valparaiso earthquake of August 1906)
    directed by comte de Montessus de Ballore.



EARTH-STAR (_Geaster_), in botany, a kind of puff-ball, with a distinct
outer coat which, on separating from the inner, splits into several
divisions, which become reflexed and spread like a star. The inner coat
enveloping the spores is supported, like a ball, either with or without
a stalk on the upper face of the star. The spores escape generally by
means of a distinct aperture which appears in the top of the ball. There
are several species in Britain found on the ground or on decaying
leaves. They are rare or local, but more common in the south or
south-east of England than in other parts of Britain.

[Illustration: From Strasburger's _Lehrbuch der Botanik_, by permission
of Gustav Fischer.

_Geaster Granulosus_, nat. size.]



EARTHWORM, the common name of a chaetopod worm found nearly all over the
world. Linnaeus recognized only one species of earthworm and named it
_Lumbricus terrestris_. There are now one thousand well-characterized
species known from different parts of the world, and the number
increases almost daily. The earthworms of England belong entirely to the
three genera _Lumbricus_, _Allolobophora_ and _Allurus_, which are
further subdivided by some systematists; and these genera form the
prevalent earthworm fauna of the Palaearctic region and are also very
numerous in the Nearctic region. Elsewhere they do not appear to be
indigenous, but are replaced by the numerous other genera of the
families enumerated in the article CHAETOPODA (q.v.). It is a remarkable
fact that these genera, comprizing a separate family _Lumbricidae_, when
introduced into tropical and other countries, thrive abundantly and oust
the indigenous forms. In gatherings of earthworms from various
extra-European countries it is always found that if the collections have
been made in cultivated ground and near the coast the worms are of
European species; farther inland the native forms are met with. Inasmuch
as in every case the _Lumbricidae_ from non-European countries are
identical with European species, since it has been shown that these
animals are very readily introduced accidentally with plants, &c., and
in view of the fact that they are impatient of sea water, it seems clear
that the presence of these _Lumbricidae_ in other continents is due to
accidental transportation. Most earthworms live in the soil, which they
devour as they burrow through it. A few, like their allies the river
worms (Limicolae), habitually frequent streams, lakes, &c. One genus, at
any rate, viz. _Pontodrilus_, seeks an unusual environment, and is found
in heaps of sea-weed cast up by the sea. The range of this genus is
therefore naturally wider than that of other genera which are confined
to land masses and cannot cross the sea by their own efforts. It might
be inferred, therefore, and the inference is proved by facts, that truly
oceanic islands have no indigenous fauna of earthworms, but are
inhabited by forms which are identical with those of neighbouring
continents, and doubtless, therefore, accidentally introduced.

Like the leeches the earthworms produce cocoons which are a product of
the glandular epithelium of the clitellum. In these cocoons are
deposited the eggs together with a certain amount of albumen upon which
the developing embryos feed. So far as is known, the production of
cocoons is universal among earthworms and the remaining Oligochaeta of
aquatic habit. The young leave the cocoon as fully formed earthworms in
which, however, the genitalia are not fully developed. There is no free
living larval stage. Out of a single cocoon emerge a varying number of
young worms, the numbers being apparently characteristic of the species.
The work of earthworms in aiding in the production of the subsoil and in
levelling the surface was first studied by C. Darwin, and has since been
investigated by others. This work is partly carried out beneath the
surface and partly on the surface, upon which the worms wander at night
and eject the swallowed and triturated earth; frequently castings of
some height are formed of coiled ropes of agglutinated particles of
mould. The indigenous species of Great Britain, about twenty in number,
do not grow to a greater length than some 10 in.; but in several
tropical countries there are species which grow to a length of from 3 to
6 ft. Thus we have in Natal the gigantic _Microchaeta rappi_, in Ceylon
_Megascolex coeruleus_, in Australia _Megascolides australis_, and an
equally large form in South America.     (F. E. B.)



EARWIG, an insect belonging to the _Forficulidae_, a family usually
referred to the Orthoptera, but sometimes regarded as typifying a
special order, to which the names Dermaptera, Dermatoptera and
Euplexoptera have been given, in allusion to certain peculiarities in
the structure of the wings in the species that possess them. The front
wings are short and horny and when at rest meet without overlapping in
the middle line, like the wing-cases of brachelytrous (cocktail)
beetles. The hind wings, on the contrary, are for the most part
membranous and, when extended, of large size; each consists of two
portions, the distal of which, in virtue of the arrangement and jointing
of its nervures, is capable of being both doubled up and folded fanwise
beneath the proximal, which is partly horny when the wing is tucked away
under the front wing-case of the same side. Apart from these
characteristics, the most distinctive feature of earwigs is the presence
at the end of the abdomen of a pair of pincers which are in reality
modified appendages, known as cercopods, and represent the similar limbs
of _Japyx_ and the caudal feelers of _Campodea_ and some other insects.

The _Forficulidae_ are almost cosmopolitan; but the various species and
genera differ from each other both in structure and size to a
comparatively slight extent. The length and armature of the pincers and
the presence or absence of wings are perhaps the most important features
used by systematists in distinguishing the various kinds. Of particular
zoological interest in this connexion is a Ceylonese genus _Dyscritina_,
in which the cercopods are long, many-jointed and filiform during the
early stages of growth, and only assume at the last moult the forcipate
structure characteristic of the family. The best known earwig is the
common European species, _Forficula auricularia_. This insect is
gregarious and nocturnal. It hides by day under stones or the loosened
bark of trees or in any crevice or hole sheltered from the light. At
night it crawls about in search of food, which consists to a small
extent of dead animal or vegetable matter, but principally, as gardeners
are aware, of the petals and other parts of flowers of growing shoots
and soft ripe fruit. During the winter earwigs lie dormant; but in the
early months of the year females with their eggs may be found in the
soil, frequently in deserted earthworm burrows. Maternal instincts are
well developed, both the eggs, which number about fifty, and the young
being carefully brooded and watched over by the parent. Except for the
absence of wings, the young are miniature models of the adult. As growth
proceeds the integument is periodically cast; and at the final moult the
perfect winged insect appears. Males and females are like each other in
size, but may be distinguished by the difference in the number of
visible abdominal segments, the male having nine and the female seven.
In the male, moreover, the pincers are caliper-like and toothed at the
base, whereas in the female they are untoothed and only lightly curved
at the tip. These differences suggest that the pincers aid in the
pairing of the sexes. However that may be, they are known to be used in
the folding of the wings; and their importance as weapons of defence is
attested by the precision and effect with which they are wielded against
assailants like ants.     (R. I. P.)



EASEMENT (Fr. _aise_; O. Fr. _aisement_; Anglo-Lat. _aisiamentum_, a
privilege or convenience), in English law, a species of "servitude" or
limited right of use over land belonging to another. It is distinguished
from _profits à prendre_--another species of servitude which involves a
right to participate in the profits of the soil of another--since an
easement confers merely a convenience (_aisiamentum_) to be exercised
over the land of another (without any participation in the profits of
it), i.e. a right to use the soil or produce of the soil in a way
tending to the more convenient enjoyment of another piece of land. Thus
a right of way is an easement, a right of common is a profit. An
easement is distinguishable also from a licence, which, unless it is
coupled with a grant, is personal to both grantor and grantee and is
neither binding on the licensor, nor, in general, assignable by the
licensee; while both the benefit and the burden of an easement are
annexed to land (Gale on _Easements_, 8th ed. p. 2). With easements are
sometimes classed certain closely allied "natural rights," such as a
landowner's right to lateral support for his soil in its natural state,
and a riparian owner's right to the natural flow of a stream.

The essential features of an easement, in the strict sense of the term,
are therefore these: (i.) It is an incorporeal right; a right to the use
and enjoyment of land--not to the land itself; (ii.) it is imposed upon
corporeal property; (iii.) it is a right without profit; (iv.) it
requires for its constitution two distinct tenements--the "dominant
tenement" which enjoys the right, and the "servient tenement" which
submits to it. This last characteristic excludes from the category of
easements the so-called "easements _in gross_," such as a right of way
conferred by grant independently of the possession of any tenement by
the grantee. The true easement is an "appendant" or "appurtenant" right,
not a "right in gross."

Further classifications of easements must be noted. They are divided
into (a) _affirmative_ or _positive_, those which authorize the
commission of an act by the dominant owner, e.g. rights of way, a right
to draw water from a spring, rights of aqueduct, and _negative_, when
the easement restricts the rights of the servient owner over his own
property, e.g. prevents him from building on land so as to obstruct
ancient lights (cf. also the right to the support of neighbouring soil);
(b) _continuous_, of which the enjoyment may be continual without the
interference of man, e.g. access to light, and _discontinuous_, where
there must be a fresh act on each occasion of the exercise of the right,
e.g. a right of way, or right to draw water; (c) _apparent_, where there
are visible external signs of the exercise of the right, e.g. a right to
dam up a watercourse, and _non-apparent_, where such signs are absent,
e.g. a right to lateral support from land, a prohibition to build above
a certain height.

_Acquisition of Easements._--Easements may be acquired (a) by express
grant, either by statute, or by deed _inter vivos_, or by will; (b) by
an implied grant; (c) by express or implied reservation, e.g. by the
owner of land in selling the fee (as to implied reservation, see Gale on
_Easements_, 8th ed. pp. 137 et seq.); (d) by prescription, either at
common law or under the Prescription Act 1832. An express grant, or
express reservation, of an easement cannot be effected except by deed.
An easement arises by implied grant where a man makes one part of his
tenement dependent on another, or makes the parts mutually
interdependent, and grants any such part with the dependence attaching
to it to another person (Innes, _Law of Easements_, 7th ed. p. 10). For
example, a man builds two houses, each of which by the plan of
construction receives support from the other; this mutual right of
support is a _quasi_-easement, of which on severance of the tenements
the grantee of one will have the benefit; where the enjoyment of the
severed tenement could not be had at all without such a right, it is
said to be an "easement of necessity."

Easements are acquired by prescription at common law by proof of
"immemorial user" by the dominant owner and those through whom he
claims. At one time it was thought that such proof must date back to the
first year (1189) of Richard I. (see preamble to Prescription Act 1832).
The ground, however, on which prescription was admitted as a means of
acquiring easements was the fiction of a "lost grant." Long enjoyment of
the right pointed to its having had a legal origin in a grant from the
servient owner, and so any period of reasonably long use came to be
accepted. A "lost grant" may be presumed to have been made (the question
is one of fact) if 20 years' uninterrupted enjoyment is shown. To avoid
the difficulties of proof of prescriptive right at common law, the
Prescription Act 1832 established shorter periods of user. In the case
of easements, other than light, the periods of prescription are 20 years
for a claim that may be defeated, and 40 years for an indefeasible claim
(s. 2). The right of access of light is dealt with under s. 3 (see
ANCIENT LIGHTS). The enjoyment to become prescriptive must be open, i.e.
of such a character that the owner of the tenement said to be servient
has a reasonable opportunity of becoming aware of the adverse claim
(_Union Lighterage Co._ v. _London Graving Dock Co._, 1902, 2 Ch. 557);
and it must be enjoyed as of right (_Gardner_ v. _Hodgson's Kingston
Brewery Co._, 1903, A.C. 229) as against the owner of the tenement
affected (_Kilgour_ v. _Gaddes_, 1904, 1 K.B. 457). The periods of
prescription are to be reckoned backwards from the time when some suit
or matter involving the claim of the dominant owner has arisen (s. 4).
Nothing is to be deemed an interruption unless the act of interruption
has been submitted to, or acquiesced in, for a year (s. 4).

Easements may be extinguished (i.) by express release--here an
instrument under seal is necessary; (ii.) by "merger," i.e. where both
tenements become the property of the same owner; (iii.) by abandonment
through non-user. In the case of discontinuous easements, the shortest
period of non-user may suffice if there is direct evidence of an
intention to abandon.

A word may be added here as to the right to air. It is an actionable
nuisance to cause pollution of the air entering a dwelling-house. The
owner of a dwelling-house may by prescription acquire a right to the
passage of air through it by a defined channel; and the enjoyment
without interruption of ventilation by means of air flowing in a
definite channel, with the knowledge of the owner and occupier of the
adjoining premises, creates a presumption of the grant of such an
easement (see Gale on _Easements_, 8th ed. p. 338).

In _Scots Law_ the term "easement" is unknown. Both the name "servitude"
and the main species of servitudes existing in Roman law (q.v.) have
been adopted. The classification of servitudes into positive and
negative, &c., and the modes of their creation and extinction, are
similar to those of English law. The statutory period of prescription is
40 years (Scots Acts 1617, c. 12), or 20 years in the case of enjoyment
under any _ex facie_ valid irredeemable title duly recorded in the
appropriate register of sasines (Conveyancing [Scotland] Act 1874).
There are certain servitudes special to Scots law, e.g. "thirlage," by
which lands are "thirled" or bound to a particular mill, and the
possessors obliged to grind their grain there, for payment of certain
_multures_ (quantities of grain or meal, payable to the mill-owner) and
_sequels_ (small quantities given to the mill servants) as the customary
price of grinding. Statutory provision has been made for the commutation
of these duties (Thirlage Act 1799), and they have now almost
disappeared.

The French Code Civil (Arts. 637 et seq.) and the other European codes
(e.g. Belgium, arts. 637 et seq.; Holland, arts. 721 et seq.; Italy,
arts. 531 et seq.; Spain, arts. 530 et seq.; Germany, arts. 1018 et
seq.) closely follow Roman law. French law is in force in Mauritius, and
has been followed in Quebec (Civil Code, arts. 499 et seq.) and St Lucia
(Civil Code, arts. 449 et seq.). In India the law is regulated, on
English lines, by the Easements Act 1882 (Act v. of 1882). The term
"easements," however, in India includes _profits à prendre_. In the
South African colonies the law of easements is based on the Roman Dutch
law (see Maasdorp, _Institutes of Cape Law_, 1904; Bk. ii. p. 166 et
seq.). In most of the other colonies the law of easements is similar to
English law. In some, however, it has been provided by statute that
rights to the access and use of light or water cannot be acquired by
prescription: e.g. Victoria (Water Act 1890, No. 1156, s. 3), Ontario
(Real Property Limitation Act, Revised Stats. Ontario, 1897; c. 133, s.
36, light).

In the _United States_ the law of easements is founded upon, and
substantially identical with, English law. The English doctrine,
however, as to acquisition of right of light and air by prescription is
not accepted in most of the States.

  AUTHORITIES.--_English Law_: Gale, _Law of Easements_ (8th ed.,
  London, 1908); Goddard, _Law of Easements_ (6th ed., London, 1904);
  Innes, _Digest of the Law of Easements_ (7th ed., London, 1903).
  _Indian Law_: Peacock, _Easements in British India_ (Calcutta, 1904);
  Hudson and Inman, _Law of Light and Air_ (2nd ed., London, 1905).
  _Scots Law_: Erskine, _Principles of the Law of Scotland_ (20th ed.,
  Edinburgh, 1903). _American Law_: Jones, _Law of Easements_ (New York,
  1898); Bouvier, _Law Dict._ (Boston and London, 1897); _Ruling Cases_,
  London and Boston, 1894-1901, tit. _Easement_ (American Notes).
       (A. W. R.)



EAST, ALFRED (1849-   ), English painter and etcher, was born at
Kettering on the 15th of December 1849. One of the most prominent among
modern English landscape painters, he received his art education first
at the Glasgow School of Art and then in Paris at the École des
Beaux-Arts, and under Robert-Fleury and Bouguereau. His landscapes are
remarkable for the lyrical use of colour and for the pleasing rhythm of
line which is the result of careful selection and building up of the
elements that constitute the scene. Based on keen observation of the
colour of nature and on careful studies of the details, they are
arranged with a rare and by no means obvious sense of balance and
compositional beauty which summarily discards all disturbing accidents
of nature. He also achieved distinction as an etcher, and published an
instructive and useful volume on landscape painting (London, 1906). He
began to exhibit at the Royal Academy in 1882, and was elected an
associate. In 1906 he became president of the Royal Society of British
Artists. Many of his works are to be found in the English provincial
galleries; Manchester owns "The Silent Somme" and "Autumn"; Liverpool,
"Gibraltar from Algeciras"; Leeds, "The Golden Valley"; Birmingham,
"Hayle from Lelant"; Preston, "An Idyll of Spring"; and Hull, "Evening
on the Cotswolds." His "Passing Storm" is at the Luxembourg; "The Nene
Valley" at the Venice gallery; and "A Haunt of Ancient Peace" at the
National gallery in Budapest. In 1903 he received the order of the Crown
of Italy in connexion with his services to the Venice international
exhibition; and he was made an honorary member of the Japanese Meiji
Bijutsu Kai.



EAST ANGLIA, one of the kingdoms into which Anglo-Saxon Britain was
divided. Bede gives no information about its origin except that its
earliest settlers were Angles. The kingdom of East Anglia comprised the
two counties of Norfolk and Suffolk. With regard to the western boundary
we have no accurate information, but it was probably formed by the fens
of Cambridgeshire.

This kingdom first appears in Bede's narrative early in the 7th century,
when its power was at its height. Towards the end of the reign of
Æthelberht, who died about 616, Rædwald of East Anglia, who had
apparently spent some time at the court of Kent, began to win for
himself the chief position among the Anglo-Saxon kings of his day. His
position was assured, at least temporarily, in 617, when he decided to
espouse the cause of the Northumbrian prince Edwin, then a fugitive at
his court, and defeated Æthelfrith of Northumbria on the banks of the
Idle, a tributary of the Trent, in Mercian territory. Rædwald had been
converted to Christianity in Kent, but after his return home he
relapsed, according to Bede, owing to the influence of his wife, and
there were to be seen in the same building a Christian and a pagan
altar. Bede states that Rædwald was the son of Tytili, the son of Wuffa,
from whom the East Anglian royal family derived their name Wuffingas.
According to the _Historia Brittonum_ Guffa (Wuffa) was the son of
(Guecha) Wehha, who first ruled the East Angles in Britain. This would
put the organization of the kingdom in the first or second quarter of
the 6th century. Eorpwald, the son of Rædwald, was converted to
Christianity by Edwin, but was soon afterwards slain by Ricberht (627 or
628), whereupon the kingdom again became pagan for three years, when
Sigeberht, the brother of Eorpwald, became king and founded a see for
Felix at Dunwich. Sigeberht also founded a school in East Anglia, and on
the arrival of an Irish missionary named Furseus he built him a
monastery at _Cnobheresburg_, perhaps to be identified with Burgh
Castle. Before 644, however, Sigeberht resigned the crown in favour of
his brother Ecgric and retired to a monastery. Shortly afterwards both
brothers were slain by Penda of Mercia in his invasion of East Anglia,
and Anna became king. This king was an enthusiastic Christian, and
converted Coenwalh, king of Wessex, who had fled to his court. Two of
his daughters, Sæthryth and Æthelberg, took the veil; while another,
Sexburg, was married to Earconberht, king of Kent; and a fourth,
Æthelthryth, after two marriages, with Tondberht of the South Gyrwe and
Ecgfrith of Northumbria, became abbess of Ely. In 654 Anna was slain by
Penda of Mercia, and was succeeded by his brother Æthelhere, who was
killed in 655 at the Winwaed, fighting for the Mercian king against
Oswio of Northumbria. In 673 Archbishop Theodore divided the East
Anglian diocese into two, Elmham being the seat of the northern, Dunwich
that of the southern bishop. A long blank follows in the history of this
kingdom, until in 792 we find Offa of Mercia slaying Æthelberht, king of
East Anglia, who is said to have been his son-in-law. East Anglia was
subject to the supremacy of the Mercian kings until 825, when its people
slew Beornwulf of Mercia, and with their king acknowledged Ecgberht
(Egbert) of Wessex as their lord. In 870 Edmund, king of East Anglia,
was killed by the Danes under I'varr and Ubbi, the sons of Ragnar
Loðbrok.

The following is a list of the kings of East Anglia of whom there is
record:--Wehha; Wuffa; Rædwald, son of Tytili and grandson of Wuffa
(reigning 617); Eorpwald, son of Rædwald (d. 627 or 628); Sigeberht,
brother of Eorpwald; Ecgric, brother of Sigeberht (both slain before
644); Anna, son of Ene and grandson of Tytili (d. 654); Æthelhere,
brother of Anna (d. 655); Æthelwald, a third brother; Aldwulf (succ.
663, d. 713), son of Æthelric and grandson of Ene; Elfwald, son of
Aldwulf (d. 749); Hun Beonna and Alberht; Æthelberht (792); Edmund
(870).

After the death of Ragnar Loðbrok's sons East Anglia was occupied by the
Danish king Guthrum, who made a treaty with Alfred settling their
respective boundaries, probably about 880. Guthrum died in 890. A later
king named Eohric took up the cause of Æthelwald, the son of Æthelred
I., and was slain in the fight with the Kentish army at the Holm in 905.
A war broke out with King Edward the Elder in 913; in 921 a king whose
name is unknown was killed at the fall of Tempsford, and in the same
year the Danes of East Anglia submitted to Edward the Elder. From this
time, probably, East Anglia was governed by English earls, the most
famous of whom were Æthelstan, surnamed Half-King (932-956) and his
sons, Æthelwold (956-962), and Æthelwine, surnamed _Dei amicus_
(962-992).

  See Bede, _Hist. Eccl._ (ed. C. Plummer, Oxford. 1896), ii. 5, 15,
  iii. 7, 8, 18-20, 22, iv. 3, 5, 23; _Saxon Chronicle_ (ed. Earle and
  Plummer, Oxford, 1899), s. a. 823, 838, 866, 870, 880, 885, 890, 894,
  905, 921; _Historia Brittonum_ (San-Marte, 1844), s. 59; H. Sweet,
  _Oldest English Texts_, p. 171 (London, 1885).     (F. G. M. B.)



EASTBOURNE, a municipal borough (1883) in the Eastbourne parliamentary
division of Sussex, England, 61 m. S.S.E. of London by the London,
Brighton & South Coast railway. Pop. (1891) 34,969; (1901) 43,344;
(local census, 1909) 49,286. It is situated 3 m. N.E. of Beachy Head,
the loftiest headland on the English Channel coast. It once consisted of
three parts--the village of East Bourne, a mile inland; South Bourne,
lying back from the shore; and Seahouses, facing the beach. The church
of St Mary, the ancient parish church of East Bourne, is a fine
transitional Norman building; and there are numerous modern churches and
chapels. The principal buildings and institutions are the town hall and
municipal buildings, the Princess Alice Memorial and other hospitals, a
free library and, among many high-class schools, Eastbourne College for
boys, founded in 1867. There is a fine pier with pavilion, and a marine
parade nearly 3 m. in extent, arranged in terraced promenades.
Devonshire Park of 13 acres is pleasantly laid out, and contains a
pavilion and a theatre. The duke of Devonshire is the principal
landowner. Golf links are laid out on the neighbouring downs. A Roman
villa was formerly seen close to the shore, but it is not now visible.
The corporation consists of a mayor, 8 aldermen and 24 councillors. In
1910 the corporation promoted a bill in parliament to add the Hampden
Park district in the parish of Willingdon to the borough and to make
Eastbourne, with this extension, a county borough.



EAST CHICAGO, a city of Lake county, Indiana, U.S.A., on Lake Michigan,
about 19 m. S.E. of the business centre of Chicago. Pop. (1890) 1255;
(1900) 3411 (1331 foreign-born); (1910) 19,098. It is served by several
railways, including the Pennsylvania, the Wabash, the Chicago Terminal
Transfer (whose shops are here), the Lake Shore & Michigan Southern, the
Chicago, Indiana & Southern, and the Indiana Harbor railways. East
Chicago covers an area whose greatest dimensions are 4 by 3½ m. That
part of the city along the lake, known as Indiana Harbor, dates from
1901 and has grown very rapidly because of its position at the
southernmost part of the Calumet District, and because of the meeting
here of railway and lake commerce. A good harbour has been constructed,
a new ship canal connecting the harbour with the Calumet river. East
Chicago is industrially virtually a part of "Greater" Chicago; among its
manufactures are iron and steel, cement, lumber, boilers, hay presses,
chains, chemicals and foundry products. East Chicago was chartered as a
city in 1893.



EASTER, the annual festival observed throughout Christendom in
commemoration of the resurrection of Jesus Christ. The name Easter (Ger.
_Ostern_), like the names of the days of the week, is a survival from
the old Teutonic mythology. According to Bede (_De Temp. Rat._ c. xv.)
it is derived from _Eostre_, or _Ostâra_, the Anglo-Saxon goddess of
spring, to whom the month answering to our April, and called
_Eostur-monath_, was dedicated. This month, Bede says, was the same as
the _mensis paschalis_, "when the old festival was observed with the
gladness of a new solemnity."

The name of the festival in other languages (as Fr. _pâques_; Ital.
_pasqua_; Span. _pascua_; Dan. _paaske_; Dutch _paasch_; Welsh _pasg_)
is derived from the Lat. _pascha_ and the Gr. [Greek: pascha]. These in
turn come from the Chaldee or Aramaean form [Hebrew: pascha] _pascha'_,
of the Hebrew name of the Passover festival [Hebrew: pesach] _pesach_,
from [Hebrew: pasach] "he passed over," in memory of the great
deliverance, when the destroying angel "passed over the houses, of the
children of Israel in Egypt when he smote the Egyptians" (Exod. xii.
27).

An erroneous derivation of the word _pascha_ from the Greek [Greek:
paschein], "to suffer," thus connected with the sufferings or passion of
the Lord, is given by some of the Fathers of the Church, as Irenaeus,
Tertullian and others, who were ignorant of Hebrew. St Augustine (_In
Joann. Tract._ 55) notices this false etymology, shows how similarity of
sound had led to it, and gives the correct derivation.

There is no indication of the observance of the Easter festival in the
New Testament, or in the writings of the apostolic Fathers. The sanctity
of special times was an idea absent from the minds of the first
Christians. "The whole of time is a festival unto Christians because of
the excellency of the good things which have been given" is the comment
of St Chrysostom on 1 Cor. v. 7, which has been erroneously supposed to
refer to an apostolic observance of Easter. The ecclesiastical historian
Socrates (_Hist. Eccl._ v. 22) states, with perfect truth, that neither
the Lord nor his apostles enjoined the keeping of this or any other
festival. He says: "The apostles had no thought of appointing festival
days, but of promoting a life of blamelessness and piety"; and he
attributes the observance of Easter by the church to the perpetuation of
an old usage, "just as many other customs have been established."

This is doubtless the true statement of the case. The first Christians
continued to observe the Jewish festivals, though in a new spirit, as
commemorations of events which those festivals had foreshadowed. Thus
the Passover, with a new conception added to it of Christ as the true
Paschal Lamb and the first fruits from the dead, continued to be
observed, and became the Christian Easter.

Although the observance of Easter was at a very early period the
practice of the Christian church, a serious difference as to the day for
its observance soon arose between the Christians of Jewish and those of
Gentile descent, which led to a long and bitter controversy. The point
at issue was when the Paschal fast was to be reckoned as ending. With
the Jewish Christians, whose leading thought was the death of Christ as
the Paschal Lamb, the fast ended at the same time as that of the Jews,
on the fourteenth day of the moon at evening, and the Easter festival
immediately followed, without regard to the day of the week. The Gentile
Christians, on the other hand, unfettered by Jewish traditions,
identified the first day of the week with the Resurrection, and kept the
preceding Friday as the commemoration of the crucifixion, irrespective
of the day of the month. With the one the observance of the day of the
month, with the other the observance of the day of the week, was the
guiding principle.

Generally speaking, the Western churches kept Easter on the first day of
the week, while the Eastern churches followed the Jewish rule, and kept
Easter on the fourteenth day. St Polycarp, the disciple of St John the
Evangelist and bishop of Smyrna, visited Rome in 159 to confer with
Anicetus, the bishop of that see, on the subject; and urged the
tradition, which he had received from the apostle, of observing the
fourteenth day. Anicetus, however, declined to admit the Jewish custom
in the churches under his jurisdiction, but readily communicated with
Polycarp and those who followed it. About forty years later (197) the
question was discussed in a very different spirit between Victor, bishop
of Rome, and Polycrates, metropolitan of proconsular Asia. That province
was the only portion of Christendom which still adhered to the Jewish
usage, and Victor demanded that all should adopt the usage prevailing at
Rome. This Polycrates firmly refused to agree to, and urged many weighty
reasons to the contrary, whereupon Victor proceeded to excommunicate
Polycrates and the Christians who continued the Eastern usage. He was,
however, restrained from actually proceeding to enforce the decree of
excommunication, owing to the remonstrance of Irenaeus and the bishops
of Gaul. Peace was thus maintained, and the Asiatic churches retained
their usage unmolested (Euseb. _H.E._ v. 23-25). We find the Jewish
usage from time to time reasserting itself after this, but it never
prevailed to any large extent.

A final settlement of the dispute was one among the other reasons which
led Constantine to summon the council of Nicaea in 325. At that time the
Syrians and Antiochenes were the solitary champions of the observance of
the fourteenth day. The decision of the council was unanimous that
Easter was to be kept on Sunday, and on the same Sunday throughout the
world, and "that none should hereafter follow the blindness of the
Jews" (Socrates, _H.E._ i. 9). The correct date of the Easter festival
was to be calculated at Alexandria, the home of astronomical science,
and the bishop of that see was to announce it yearly to the churches
under his jurisdiction, and also to the occupant of the Roman see, by
whom it was to be communicated to the Western churches. The few who
afterwards separated themselves from the unity of the church, and
continued to keep the fourteenth day, were named _Quartodecimani_, and
the dispute itself is known as the _Quarto-deciman_ controversy.
Although measures had thus been taken to secure uniformity of
observance, and to put an end to a controversy which had endangered
Christian unity, a new difficulty had to be encountered owing to the
absence of any authoritative rule by which the paschal moon was to be
ascertained. The subject is a very difficult and complex one (see also
CALENDAR). Briefly, it may be explained here that Easter day is the
first Sunday after the full moon following the vernal equinox. This, of
course, varies in different longitudes, while a further difficulty
occurred in the attempt to fix the correct time of Easter by means of
cycles of years, when the changes of the sun and moon more or less
exactly repeat themselves. At first an eight years' cycle was adopted,
but it was found to be faulty, then the Jewish cycle of 84 years was
used, and remained in force at Rome till the year 457, when a more
accurate calculation of a cycle of 532 years, invented by Victorius of
Acquitaine, took its place. Ultimately a cycle of 19 years was accepted,
and it is the use of this cycle which makes the Golden Number and Sunday
Letter, explained in the preface to the Book of Common Prayer,
necessary. Owing to this lack of decision as to the accurate finding of
Easter, St Augustine tells us (_Epist._ 23) that in the year 387 the
churches of Gaul kept Easter on the 21st of March, those of Italy on the
18th of April, and those of Egypt on the 25th of April; and it appears
from a letter of Leo the Great (_Epist._ 64, _ad Marcian._) that in 455
there was a difference of eight days between the Roman and the
Alexandrine Easter. Gregory of Tours relates that in 577 "there was a
doubt about Easter. In Gaul we with many other cities kept Easter on the
fourteenth calends of May, others, as the Spaniards, on the twelfth
calends of April."

The ancient British and Celtic churches followed the cycle of 84 years
which they had originally received from Rome, and their stubborn refusal
to abandon it caused much bitter controversy in the 8th century between
their representatives and St Augustine of Canterbury and the Latin
missionaries. These latter unfairly attempted to fix the stigma of the
Quartodeciman observance on the British and Celtic churches, and they
are even now sometimes ignorantly spoken of as having followed the
Asiatic practice as to Easter. This, however, is quite erroneous. The
British and Celtic churches always kept Easter according to the Nicene
decree on a Sunday. The difference between them and the Roman Church, at
this period, was that they still followed the 84 years' cycle in
computing Easter, which had been abandoned at Rome for the more accurate
cycle of 532 years. This difference of calculation led to Easter being
observed on different Sundays, in certain years, in England, by the
adherents of the two churches. Thus Bede records that in a certain year
(which must have been 645, 647, 648 or 651) Queen Eanfleda, who had
received her instruction from a Kentish priest of the Roman obedience,
was fasting and keeping Palm Sunday, while her husband, Oswy, king of
Northumbria, following the rule of the British church, was celebrating
the Easter festival. This diversity of usage was ended, so far as the
kingdom of Northumbria was concerned, by the council of Streaneshalch,
or Whitby, in 654. To Archbishop Theodore is usually ascribed the credit
of ending the difference in the rest of England in 669.

The Gregorian correction of the calendar in 1582 has once more led to
different days being observed. So far as Western Christendom is
concerned the corrected calendar is now universally accepted, and Easter
is kept on the same day, but it was not until 1752 that the Gregorian
reformation of the calendar was adopted in Great Britain and Ireland.
Jealousy of everything emanating from Rome still keeps the Eastern
churches from correcting the calendar according to the Gregorian
reformation, and thus their Easter usually falls before, or after, that
of the Western churches, and only very rarely, as was the case in 1865,
do the two coincide.

Easter, as commemorating the central fact of the Christian religion, has
always been regarded as the chief festival of the Christian year, and
according to a regulation of Constantine it was to be the first day of
the year. This reckoning of the year as beginning at Easter lingered in
France till 1565, when, by an ordinance of Charles IX., the 1st of
January finally took its place.

Four different periods may be mentioned as connected with the observance
of Easter, viz. (1) the preparatory fast of the forty days of Lent; (2)
the fifteen days, beginning with the Sunday before and ending with the
Sunday after Easter, during which the ceremonies of Holy Week and the
services of the Octave of Easter were observed; this period, called by
the French the _Quinzaine de Pâques_, was specially observed in that
country; (3) the Octave of Easter, during which the newly-baptized wore
their white garments, which they laid aside on the Sunday after Easter,
known as _Dominica in albis depositis_ from this custom; another name
for this Sunday was _Pascha clausum_, or the close of Easter, and from a
clipping of the word "close" the English name of "Low" Sunday is
believed to be derived; (4) Eastertide proper, or the paschal season
beginning at Easter and lasting till Whit Sunday, during the whole of
which time the festival character of the Easter season was maintained in
the services of the church.

Many ecclesiastical ceremonies, growing up from early times, clustered
round the celebration of the Easter festival. One of the most notable of
these was the use of the paschal candle. This was a candle of very large
dimensions, set in a candlestick big enough to hold it, which was
usually placed on the north side, just below the first ascent to the
high altar. It was kept alight during each service till Whitsuntide. The
Paschal, as it was called at Durham cathedral, was one of the chief
sights of that church before the Reformation. It was an elaborate
construction of polished brass, and, contrary to the usual custom, seems
to have been placed in the centre of the altar-step, long branches
stretching out towards the four cardinal points, bearing smaller
candles. The central stem of the candlestick was about 38 ft. high, and
bore the paschal candle proper, and together they reached a combined
height of about 70 ft., the candle being lighted from an opening above.
Other paschal candles seem to have been of scarcely less size. At
Lincoln, c. 1300, the candle was to weigh three stones of wax; at
Salisbury in 1517 it was to be 36 ft. long; and at Westminster in 1558
it weighed no less than 3 cwt. of wax. After Whitsuntide what remained
was made into smaller candles for the funerals of the poor. In the
ancient churches at Rome the paschal candlesticks were fixtures, but
elsewhere they were usually movable, and were brought into the church
and set up on the Thursday before Easter. At Winchester the paschal
candlestick was of silver, and was the gift of Canute. Others of more or
less importance are recorded as having been at Canterbury, Bury St
Edmunds, Hereford and York. The burning of the paschal candle still
forms part of the Easter ceremonial of the Roman Catholic Church (see
LIGHTS, CEREMONIAL).

The liturgical colour for Easter was everywhere white, as the sign of
joy, light and purity, and the churches and altars were adorned with the
best ornaments that each possessed. Flowers and shrubs no doubt in early
times were also used for this purpose, but what evidence there is goes
against the medieval use of such decorations, which are so popular at
the present day.

It is not the purpose of this article to enter on the wide subject of
the popular observances, such as the giving and sending of Pasch or
Easter eggs as presents. For such the reader may consult Brand's
_Popular Antiquities_, Hone's _Every-Day Book_, and Chambers's _Book of
Days_.

  AUTHORITIES.--Bingham, _Antiquities of the Christian Church_; Bede,
  _Ecclesiastical History of England_; Procter and Frere, _A New History
  of the Book of Common Prayer_ (London, 1901); Surtees Society, _Rites
  of Durham_, ed. J.T. Fowler (1903); De Morgan, _Companion to the
  Almanac_ (1845); De Moleon, _Voyages liturgiques_ (Paris, 1718).
       (T. M. F.)



EASTER ISLAND (Rapanui, i.e. Great Rapa), an island in the eastern part
of the South Pacific ocean, belonging to Chile (since 1888), in 27° 8'
S. and 109° 28' W., 1400 m. E. of Pitcairn, and 2000 m. from the South
American coast. It is roughly triangular in shape, with its hypotenuse
12 m. long running north-east and south-west, and its three angles
marked by three volcanic peaks, of which the north-eastern reaches 1768
ft. of altitude. The area of the island is 45 sq. m. The coast has no
good natural harbour, and landing is difficult. There is no lack of
fertile soil, and the climate is moist enough to make up for the absence
of running water. Formerly the island appears to have been wooded, but
it now presents only a few bushes (_Edwardsia_, _Broussonetia_, &c.),
ferns, grasses, sedges, &c. The natives grow bananas in the shelter of
artificial pits, also sugar-canes and sweet potatoes, and keep a few
goats and a large stock of domestic fowls, and a Tahitian commercial
house breeds cattle and sheep on the island.

It is doubtful whether Rapanui was discovered by Davis in 1686, though
it is sometimes marked Davis Island on maps. Admiral Roggeveen reached
it on Easter day 1722; in 1774 Captain Cook discovered it anew and
called it Teapi or Waihu. It was subsequently visited by La Pérouse
(1776), Kotzebue (1816), &c. At the time of Roggeveen's discovery the
island probably contained from 2000 to 3000 inhabitants of Polynesian
race, who, according to their own tradition, came from Rapa Iti (Little
Rapa) or Oparo, one of the Tubuai or Austral group. In 1863 a large
proportion of the inhabitants were kidnapped by the Peruvians and
transported to work at the guano diggings on the Chincha Islands. The
next year a Jesuit mission from Tahiti reached the island and succeeded
in the task of civilization. The natives, who number scarcely one
hundred, are all Christians.

Easter Island is famous for its wonderful archaeological remains. Here
are found immense platforms built of large cut stones fitted together
without cement. They are generally built upon headlands, and on the
slope towards the sea. The walls on the seaside are, in some of the
platforms, nearly 30 ft. high and from 200 to 300 ft. long, by about 30
ft. wide. Some of the squared stones are as much as 6 ft. long. On the
land side of the platforms there is a broad terrace with large stone
pedestals upon which once stood colossal stone images carved somewhat
into the shape of the human trunk. On some of the platforms there are
upwards of a dozen images, now thrown from their pedestals and lying in
all directions. Their usual height is from 14 to 16 ft., but the largest
are 37 ft., while some are only about 4 ft. They are formed from a grey
trachytic lava found at the east end of the island. The top of the heads
of the images is cut flat to receive round crowns made of a reddish
vesicular tuff found at a crater about 8 m. distant from the quarry
where the images were cut. A number of these crowns still lie at the
crater apparently ready for removal, some of the largest being over 10
ft. in diameter. In the atlas illustrating the voyage of La Pérouse a
plan of the island is given, with the position of several of the
platforms. Two of the images are also represented in a plate. One
statue, 8 ft. in height and weighing 4 tons, was brought to England, and
is now in the British Museum. In one part of the island are the remains
of stone houses nearly 100 ft. long by about 20 ft. wide. These are
built in courses of large flat stones fitted together without cement,
the walls being about 5 ft. thick and over 5 ft. high. They are lined on
the inside with upright slabs, on which are painted geometrical figures
and representations of animals. The roofs are formed by placing slabs so
that each course overlaps the lower one until the opening becomes about
5 ft. wide, when it is covered with flat slabs reaching from one side to
the other. The lava rocks near the houses are carved into the
resemblance of various animals and human faces, forming, probably, a
kind of picture writing. Wooden tablets covered with various signs and
figures have also been found. The only ancient implement discovered on
the island is a kind of stone chisel, but it seems impossible that such
large and numerous works could have been executed with such a tool. The
present inhabitants of Easter Island know nothing of the construction of
these remarkable works; and the entire subject of their existence in
this small and remote island is a mystery.



EASTERN BENGAL AND ASSAM, a province of British India, which was
constituted out of Assam and the eastern portion of Bengal on the 16th
of October 1905. Area 111,569 sq. m.; pop. (1901) 30,961,459. It is
situated between 20° 45' and 28° 17' N., and between 87° 48' and 97° 5'
E. The province, as thus reconstituted, consists of the Bengal districts
of Dacca, Mymensingh, Faridpur, Backergunje, Tippera, Noakhali,
Chittagong, Chittagong Hill Tracts, Rajshahi, Dinajpur, Jalpaiguri,
Rangpur, Bogra, Pabna, Malda, and the native states of Kuch Behar and
Hill Tippera; and the whole of the former area of Assam consisting of
the districts of Goalpara, Kamrup, Darrang, Nowgong, Sibsagar,
Lakhimpur, Sylhet, Cachar, Garo Hills, Khasi and Jaintia Hills, Naga
Hills and Lushai Hills. It is bounded on the N. by Bhutan, on the W. by
Burma, on the S. by Burma and the Bay of Bengal, and on the E. by
Bengal. The line of demarcation between Bengal and the new province
begins at the frontier of Bhutan, east of Darjeeling, runs south-west to
Sahibganj on the Ganges and thence follows the course of the Ganges down
to the deltaic branch, called the Haringhata, which leaves the main
stream above Goalanda, and the course of the latter, which runs south
into the Bay of Bengal. The capital of the province is Dacca, and its
chief port is Chittagong.

The Bengal districts which were transferred to Eastern Bengal and Assam
comprised northern and eastern Bengal, the most prosperous and least
overcrowded portion of Bengal. The land there is less densely populated,
wages are higher and food cheaper, and the rainfall more copious and
more regular, while the staple crops of jute, tobacco and rice command a
higher price relative to the rent of the land than in Behar or other
parts of Bengal. The population are largely Mahommedans and of a more
virile stock than the Bengali proper. Northern Bengal corresponds almost
exactly with the Rajshahi division and lies within the boundaries of the
Ganges and Brahmaputra rivers. It contains much high land of a stiff red
clay, with an undulating surface covered for the most part with scrub
jungle. The inhabitants are Indo-Chinese, not Indo-Aryans as in Bengal
proper, and are Mahommedan by religion instead of Hindu. Eastern Bengal
consists of the Dacca and Chittagong divisions which are mainly Bengali
in race and Hindu in religion. For the Assamese districts see ASSAM. The
province as a whole contains 18,036,688 Mahommedans and 12,036,538
Hindus. In language 27,272,895 of the inhabitants speak Bengali,
1,349,784 speak Assamese, and the remainder Hindi and various hill
dialects, Manipuri, Bodo, Khasi and Garo. The administration is in the
hands of a lieutenant-governor, assisted by a legislative council of
fifteen members. Under him are five commissioners, and financial matters
are regulated by a board of revenue consisting of two members.

The constitution of the new province arose out of the fact that Bengal
had grown too unwieldy for the administration of a single
lieutenant-governor. In 1868 Sir Stafford Northcote drew attention to
the greatly augmented demands that the outlying portions of Bengal made
on the time and labour of the government. At that time the population of
the province was between 40 and 50 millions, and the question was left
in abeyance until 1903, when the population had risen to 78½ millions.
In the meantime the importance of rendering Assam a self-contained and
independent administration with a service of its own, and of providing
for its future commercial expansion, had arisen. These two
considerations led Lord Curzon to propose that Bengal should be lopped
of territory both on its eastern and western borders, and that all the
districts east of the Brahmaputra should be constituted into a separate
province. This proposal was bitterly opposed by the Hindus of Bengal on
the ground that it would destroy the unity of the Bengali race; and
their agitation was associated with the _Swadeshi_ (own country)
movement for the boycott of British goods.

After the constitution of the province in October 1905, the agitation in
Eastern Bengal increased. Public meetings of protest were held,
vernacular broadsheets containing scandalous attacks on the British
authorities were circulated, schoolboys and others were organized and
drilled as so-called "national volunteers," and employed as pickets to
prevent the sale of British goods. Such was the state of things when Sir
J. Bampfylde Fuller entered on his office as first lieutenant-governor
of Eastern Bengal in January 1906. His reception was ominous.
Representative bodies that were dominated by Hindus refused to vote the
usual addresses of welcome, and non-official Hindus abstained from
paying the customary calls. There were, however, no further overt signs
of objection to the lieutenant-governor personally, and after a month or
two--in spite of, or perhaps because of, his efforts to restrain
sedition and to keep discipline in the schools--there was a decided
change in the attitude of Hindu opinion. At Dacca, in July, for
instance, the reception at Government House was attended by large
numbers of Bengali gentlemen, who assured the lieutenant-governor that
"the trouble was nearly ended." The agitation was, in fact, largely
artificial, the work of Calcutta lawyers, journalists and schoolmasters;
the mass of the people, naturally law-abiding, was unmoved by it so long
as the government showed a firm hand; while the Mussulmans, who formed a
large proportion of the whole, saw in the maintenance of the partition
and of the prestige of the British government the guarantees of their
own security.

All seemed to be going well when an unfortunate difference of opinion
occurred between the lieutenant-governor and the central government,
resulting in the resignation of Sir Bampfylde Fuller (August 1906) and
in ulterior consequences destined to be of far-reaching import. The
facts are briefly as follows. Acting on a report of Dr P. Chatterji,
inspector of schools, dated January 2, 1906, the lieutenant-governor, on
the 10th of February, addressed a letter to the registrar of Calcutta
University recommending that the privilege of affiliation to the
university should be withdrawn from the Banwarilal and Victoria high
schools at Sirajganj in Pabna, as a punishment for the seditious conduct
of both pupils and teachers. Apart from numerous cases of illegal
interference with trade and of disorder in the streets reported against
the students, two specific outrages of a serious character were
instanced as having occurred on the 15th of November: the raiding of a
cart laden with English cloth belonging to Marwari traders, and a
cowardly assault by some 40 or 50 lads on the English manager of the
Bank of Bengal. These outrages "were not the result of thoughtlessness
or sudden excitement, but were the outcome of a regularly organized
scheme, set on foot and guided by the masters of these schools, for
employing the students in enforcing a boycott." All attempts to discover
and punish the offenders had been frustrated by the refusal of the
school authorities to take action, and in the opinion of the
lieutenant-governor the only course open was to apply the remedy
suggested in the circular letter addressed to magistrates and collectors
(October 10, 1905) by Mr R.W. Carlyle, the officiating chief secretary
to the government of Bengal, directing them, in the event of students
taking any part in political agitation, boycotting and the like, to
inform the heads of schools or colleges concerned that, unless they
prevented such action being taken by the boys attending their
institutions, their grant-in-aid and the privilege of competing for
scholarships and of receiving scholarship-holders would be withdrawn,
and that the university would be asked to disaffiliate their
institutions.

The reply, dated July 5th, from the secretary in the home department of
the government of India, was--to use Sir Bampfylde's own later
expression--to throw him over. It was likely that a difference of
opinion in the syndicate of the university would arise as to the degree
of culpability that attached to the proprietors of the schools; in the
event of the syndicate taking any "punitive action," the matter was
certain to be raised in the senate, and would lead to an acrimonious
public discussion, in which the partition of Bengal and the
administration of the new province would be violently attacked; and in
the actual state of public opinion in Bengal it seemed to the government
of India highly inexpedient that such a debate should take place.
"Collective punishment," too, "would be liable to be misconstrued in
England," and the government preferred to rely on the gradual effect of
the new university regulations, which aimed "at discouraging the
participation of students in political movements by enforcing the
responsibility of masters and the managing committees of schools for
maintaining discipline."

On receipt of this communication Sir Bampfylde Fuller at once tendered
his resignation to the viceroy (July 15). He pointed out that to
withdraw from the position taken up would be "concession, not in the
interests of education, but to those people in Calcutta who have been
striving to render my government impossible, in order to discredit the
partition"; that previous concessions had had merely provocative
effects, and that were he to give way in this matter his authority would
be so weakened that he would be unable to maintain order in the country.
On the 3rd of August, after some days of deliberation, the viceroy
telegraphed saying that he was "unable to reconsider the orders sent,"
and accepting Sir Bampfylde's resignation. By the Anglo-Indian press the
news was received with something like consternation, the _Times of
India_ describing the resignation as one of the gravest blunders ever
committed in the history of British rule in India, and as a direct
incentive to the forces of disquiet, disturbance and unrest. Equally
emphatic was the verdict of the Mussulman community forming two-thirds
of the population of Eastern Bengal. On the 7th of August, the day of
Sir Bampfylde Fuller's departure from Dacca, a mass-meeting of 30,000
Mahommedans was held, which placed on record their disapproval of a
system of government "which maintains no continuity of policy," and
expressed its feeling that the lowering of British prestige must
"alienate the sympathy of a numerically important and loyal section of
His Majesty's subjects"; and many meetings of Mussulmans subsequently
passed resolutions to the same general effect. The _Akhbar-i-Islam_, the
organ of Bombay Mussulman opinion, deplored the "unwise step" taken by
the government, and ascribed it to Lord Minto's fear of the Babu press,
a display of weakness of which the Babus would not be slow to take
advantage.

This latter prophecy was not slow in fulfilling itself. So early as the
8th of August Calcutta was the scene of several large demonstrations at
which the Swadeshi vow was renewed, and at which resolutions were passed
declining to accept the partition as a settled fact, and resolving on
the continuance of the agitation. The tone of the Babu press was openly
exultant: "We have read the familiar story of the Russian traveller and
the wolves," said a leading Indian newspaper in Calcutta. "The British
government follows a similar policy. First the little babies were
offered up in the shape of the _Bande Mataram_ circular and the Carlyle
circular. Now a bigger boy has gone in the person of our own Joseph.
Courage, therefore, O wolves! Press on and the horse will soon be yours
to devour! Afterwards the traveller himself will alone be left."[1] The
task before the new lieutenant-governor of Eastern Bengal, the Hon. L.
Hare, was obviously no easy one. The encouragement given to sedition by
the weakness of the government in this case was shown by later events in
Bengal and elsewhere (see INDIA: _History, ad fin._).

For the early history of the various portions of the province see BENGAL
and ASSAM.

  See Sir James Bourdillon, _The Partition of Bengal_ (Society of Arts,
  1905); official blue-books on _The Reconstitution of the Provinces of
  Bengal and Assam_ (Cd. 2658 and 2746), and _Resignation of Sir J.
  Bampfylde Fuller_, lieutenant-governor, &c. (Cd. 3242). A long letter
  from Sir J.B. Fuller, headed _J'accuse_, attacking the general policy
  of the Indian government in regard to the seditious propaganda,
  appeared in _The Times_ of June 6, 1908.


FOOTNOTE:

  [1] Quoted by Mr F.S.P. Lely in _The Times_ of November 22, 1906.



EASTERN QUESTION, THE, the expression used in diplomacy from about the
time of the congress of Verona (1822) to comprehend the international
problems involved in the decay of the Turkish empire and its supposed
impending dissolution. The essential questions that are involved are so
old that historians commonly speak of the "Eastern Question" in
reference to events that happened long before the actual phrase was
coined. But, wherever used, it is always the Turkish Question, the
generic term in which subsidiary issues, e.g. the Greek, Armenian or
Macedonian questions, are embraced. That a phrase of so wide and loose a
nature should have been stereotyped in so narrow a sense is simply the
outcome of the conditions under which it was invented. To the European
diplomatists of the first half of the 19th century the Ottoman empire
was still the only East with which they were collectively brought into
contact. The rivalry of Great Britain and Russia in Persia had not yet
raised the question of the Middle East; still less any ambitions of
Germany in the Euphrates valley. The immense and incalculable problems
involved in the rise of Japan, the awakening of China, and their
relations to the European powers and to America--known as the Far
Eastern Question--are comparatively but affairs of yesterday.

The Eastern Question, though its roots are set far back in history--in
the ancient contest between the political and intellectual ideals of
Greece and Asia, and in the perennial rivalry of the powers for the
control of the great trade routes to the East--dates in its modern sense
from the treaty of Kuchuk Kainarji in 1774, which marked the definitive
establishment of Russia as a Black Sea power and formed the basis of her
special claims to interfere in the affairs of the Ottoman empire. The
compact between Napoleon and the emperor Alexander I. at Tilsit (1807)
marked a new phase, which culminated in 1812 in the treaty of Bucharest,
in which Russia definitely appeared as the protector of the Christian
nationalities subject to the Ottoman sultan.

The attitude of the various powers in the Eastern Question was now
defined. Russia, apart from her desire to protect the Orthodox
nationalities subject to the Ottoman power, aimed at owning or
controlling the straits by which alone she could find an outlet to the
Mediterranean and the ocean beyond. Austria, once the champion of Europe
against the Turk, saw in the Russian advance on the Danube a greater
peril than any to be feared from the moribund Ottoman power, and made
the maintenance of the integrity of Turkey a prime object of her policy.
She was thus brought into line with Great Britain, whose traditional
friendship with Turkey was strengthened by the rise of a new power whose
rapid advance threatened the stability of British rule in India. But
though Austria, Great Britain and presently France, were all equally
interested in maintaining the Ottoman empire, the failure of the
congress of Vienna in 1815 to take action in the matter of a guarantee
of Turkey, and the exclusion of the Sultan from the Holy Alliance,
seemed to endorse the claim of Russia to regard the Eastern Question as
"her domestic concern" in which "Europe" had no right to interfere. The
revolt of the Greeks (1821) put this claim to the test; by the treaty of
Adrianople (1829) Russia stipulated for their autonomy as part of the
price of peace, but the powers assembled in conference at London refused
to recognize this settlement, and the establishment of Greece as an
independent kingdom (1832) was really aimed at the pretensions and the
influence of Russia. These reached their high-water mark in the treaty
of Unkiar Skelessi (July 8th, 1832). It was no longer a question of the
partition of Turkey or of a Russian conquest of Constantinople, but of
the deliberate degradation by Russia of the Ottoman empire into a weak
state wholly dependent upon herself. The ten years' crisis (1831-1841)
evoked by the revolt of Mehemet Ali, pasha of Egypt, thus resolved
itself into a diplomatic struggle between Russia and the other powers to
maintain or to recover influence at Constantinople. The Russian
experiment of maintaining the integrity of Turkey while practically
treating her as a vassal state, ended with the compromise of 1841; and
the emperor Nicholas I. reverted to the older idea of expelling the
Turks from Europe. The Eastern Question, however, slumbered until, in
1851, the matter of the Holy Places was raised by Napoleon III.,
involving the whole question of the influence in Ottoman affairs of
France under the capitulations of 1740 and of Russia under the treaty of
1774. The Crimean War followed and in 1856 the treaty of Paris, by which
the powers hoped to stem the tide of Russian advance and establish the
integrity of a reformed Ottoman state. Turkey was now for the first
time solemnly admitted to the European concert. The next critical phase
was opened in 1871, when Russia took advantage of the collapse of France
to denounce the Black Sea clauses of the treaty of 1856. The renewal of
an aggressive policy thus announced to the world soon produced a new
crisis in the Eastern Question, which had meanwhile become complicated
by the growth of Pan-Slav ideals in eastern Europe. In 1875 a rising in
Herzegovina gave evidence of a state of feeling in the Balkan peninsula
which called for the intervention of Europe, if a disastrous war were to
be prevented. But this intervention, embodied in the "Andrassy Note"
(December 1875) and the Berlin memorandum (May 1876), met with the
stubborn opposition of Turkey, where the "young Turks" were beginning to
oppose a Pan-Islamic to the Pan-Slav ideal. The Russo-Turkish War of
1877-78 followed, concluded by the treaty of San Stefano, the terms of
which were modified in Turkey's favour by the congress of Berlin (1878),
which marks the beginning of the later phase of the Eastern Question.
Between Russia and Turkey it interposed, in effect, a barrier of
independent (Rumania, Servia) and quasi-independent (Bulgaria) states,
erected with the counsel and consent of collective Europe. It thus,
while ostensibly weakening, actually tended to strengthen the Ottoman
power of resistance.

The period following the treaty of Berlin is coincident with the reign
of Sultan Abd-ul-Hamid II. The international position of the Ottoman
empire was strengthened by the able, if Machiavellian, statecraft of the
sultan; while the danger of disruption from within was lessened by the
more effective central control made possible by railways, telegraphs,
and the other mechanical improvements borrowed from western
civilization. With the spread of the Pan-Islamic movement, moreover, the
undefined authority of the sultan as caliph of Islam received a fresh
importance even in countries beyond the borders of the Ottoman empire,
while in countries formerly, or nominally still, subject to it, it
caused, and promised to cause, incalculable trouble.

The Eastern Question thus developed, in the latter years of the 19th
century, from that of the problems raised by the impending break-up of a
moribund empire, into the even more complex question of how to deal with
an empire which showed vigorous evidence of life, but of a type of life
which, though on all sides in close touch with modern European
civilization, was incapable of being brought into harmony with it. The
belief in the imminent collapse of the Ottoman dominion was weakened
almost to extinction; so was the belief, which inspired the treaty of
1856, in the capacity of Turkey to reform and develop itself on European
lines. But the Ottoman empire remained, the mistress of vast undeveloped
wealth. The remaining phase of the Eastern Question, if we except the
concerted efforts to impose good government on Macedonia in the
interests of European peace, or the side issues in Egypt and Arabia, was
the rivalry of the progressive nations for the right to exploit this
wealth. In this rivalry Germany, whose interest in Turkey even so late
as the congress of Berlin had been wholly subordinate, took a leading
part, unhampered by the traditional policies or the humanitarian
considerations by which the interests of the older powers were
prejudiced. The motives of German intervention in the Eastern Question
were ostensibly commercial; but the Bagdad railway concession,
postulating for its ultimate success the control of the trade route by
way of the Euphrates valley, involved political issues of the highest
moment and opened up a new and perilous phase of the question of the
Middle East.

This was the position when in 1908 an entirely new situation was created
by the Turkish revolution. As the result of the patient and masterly
organization of the "young Turks," combined with the universal
discontent with the rule of the sultan and the palace _camarilla_, the
impossible seemed to be achieved, and the heterogeneous elements
composing the Ottoman empire to be united in the desire to establish a
unified state on the constitutional model of the West. The result on the
international situation was profound. Great Britain hastened to re-knit
the bonds of her ancient friendship with Turkey; the powers, without
exception, professed their sympathy with the new régime. The
establishment of a united Turkey on a constitutional and nationalist
basis was, however, not slow in producing a fresh complication in the
Eastern Question. Sooner or later the issue was sure to be raised of the
status of those countries, still nominally part of the Ottoman empire,
but in effect independent, like Bulgaria, or subject to another state,
like Bosnia and Herzegovina. The cutting of the Gordian knot by
Austria's annexation of Bosnia and Herzegovina, and by the proclamation
of the independence of Bulgaria, and of Prince Ferdinand's assumption of
the old title of tsar (king), threatened to raise the Eastern Question
once more in its acutest form. The international concert defined in the
treaty of Berlin had been rudely shaken, if not destroyed; the
denunciation by Austria, without consulting her co-signatories, of the
clauses of the treaty affecting herself seemed to invalidate all the
rest; and in the absence of the restraining force of a united concert of
the great powers, free play seemed likely once more to be given to the
rival ambitions of the Balkan nationalities, the situation being
complicated by the necessity for the dominant party in the renovated
Turkish state to maintain its prestige. During the anxious months that
followed the Austrian _coup_, the efforts of diplomacy were directed to
calming the excitement of Servians, Montenegrins and the Young Turks,
and to considering a European conference in which the _fait accompli_
should be regularized in accordance with the accepted canons of
international law. The long delay in announcing the assembly of the
conference proved the extreme difficulty of arriving at any satisfactory
basis of settlement; and though the efforts of the powers succeeded in
salving the wounded pride of the Turks, and restraining the impetuosity
of the Serbs and Montenegrins, warlike preparations on the part of
Austria continued during the winter of 1908-1909, being justified by the
agitation in Servia, Montenegro and the annexed provinces. It was not
till April 1909 (see EUROPE: ad fin.) that the crisis was ended, through
the effectual backing given by Germany to Austria; and Russia, followed
by England and France, gave way and assented to what had been done.

  See TURKEY: _History_, where cross-references to the articles on the
  various phases of the Eastern Question will be found, together with a
  bibliography. See also E. Driault, _La Question d'orient depuis son
  origine_ (Paris, 1898), a comprehensive sketch of the whole subject,
  including the Middle and Far East.     (W. A. P.)



EAST GRINSTEAD, a market town in the East Grinstead parliamentary
division of Sussex, England, 30 m. S. by E. from London by the London,
Brighton & South Coast railway. Pop. of urban district (1901) 6094. St
Swithin's church contains, among numerous ancient memorials, one of the
iron memorial slabs (1507) peculiar to certain churches of Sussex, and
recalling the period when iron was extensively worked in the district.
There may be noticed Sackville College (an almshouse founded in 1608),
and St Margaret's home and orphanage, founded by the Rev. John Mason
Neale (1818-1866), warden of Sackville College. Brewing and brick and
tile making are carried on. In the vicinity (near Forest Row station) is
the golf course of the Royal Ashdown Forest Golf Club.

The hundred of East Grinstead (Grenestede, Estgrensted) was in the
possession of the count of Mortain in 1086, but no mention of a vill or
manor of East Grinstead is made in the Domesday Survey. In the reign of
Henry III. the hundred was part of the honour of Aquila, then in the
king's hands. The honour was granted by him to Peter of Savoy, through
whom it passed to his niece Queen Eleanor. In the next reign the king's
mother held the borough of East Grinstead as parcel of the honour of
Aquila. East Grinstead was included in a grant by Edward III. to John of
Gaunt, duke of Lancaster, and it remained part of the duchy of Lancaster
until James I. granted the borough to Sir George Rivers, through whom it
was obtained by the Sackvilles, earls of Dorset. East Grinstead was a
borough by prescription. In the 16th century it was governed by an
alderman, bailiff and constable. It returned two members to parliament
from 1307 until 1832, but was disenfranchised by the Reform Act. In 1285
the king ordered that his market at Grenestede should be held on
Saturday instead of Sunday, and in 1516 the inhabitants of the town were
granted a market each week on Saturday and a fair every year on the eve
of St Andrew and two days following. Charles I. granted the earl of
Dorset a market on Thursday instead of the Saturday market, and fairs on
the 16th of April and the 26th of September every year. Thursday is
still the market-day, and cattle-fairs are now held on the 21st of April
and the 11th of December.



EAST HAM, a municipal borough in the southern parliamentary division of
Essex, England, contiguous to West Ham, and thus forming geographically
part of the eastward extension of London. Pop. (1901) 96,018. Its modern
growth has been very rapid, the population being in the main of the
artisan class. There are some chemical and other factories. The ancient
parish church of St Mary Magdalen retains Norman work in the chancel,
which terminates in an eastern apse. There is a monument for Edmund
Neville who claimed the earldom of Westmorland in the 17th century, and
William Stukeley, the antiquary, was buried in the churchyard. East Ham
was incorporated in 1904, and among its municipal undertakings is a
technical college (1905). The corporation consists of a mayor, 6
aldermen and 18 councillors. Area, 3320½ acres.



EASTHAMPTON, a township of Hampshire county, Mass., U.S.A., in the
Connecticut Valley. Pop. (1900) 5603, of whom 1731 were foreign-born;
(1905) 6808; (1910) 8524. It is served by the Boston & Maine, and the
New York, New Haven & Hartford railways, and by interurban electric
railways. The township is generally level, and is surrounded by high
hills. In Easthampton are a free public library and Williston Seminary;
the latter, one of the oldest and largest preparatory schools in New
England, was founded in 1841 by the gifts of Samuel Williston
(1795-1874) and Emily Graves Williston (1797-1885). Mr and Mrs Williston
built up the industry of covering buttons with cloth, at first doing the
work by hand, then (1827) experimenting with machinery, and in 1848
building a factory for making and covering buttons. As the soil was
fertile and well watered, the township had been agricultural up to this
time. It is now chiefly devoted to manufacturing. Among its products are
cotton goods, especially mercerised goods, for the manufacture of which
it has one of the largest plants in the country; rubber, thread, elastic
fabrics, suspenders and buttons. Parts of Northampton and Southampton
were incorporated as the "district" of Easthampton in 1785; it became a
township in 1809, and in 1841 and 1850 annexed parts of Southampton.



EAST HAMPTON, a township of Suffolk county, New York, in the extreme
S.E. part of Long Island, occupying the peninsula of Montauk, and
bounded on the S. and E. by the Atlantic Ocean, and on the N. by Block
Island Sound, Gardiner's Bay and Peconic Bay. Pop. (1900) 3746; (1905)
4303; (1910) 4722. The township, 25 m. long and 8 m. at its greatest
width from north to south, has an irregular north coast-line and a very
regular south coast-line. The surface is rougher to the west where there
are several large lakes, notably Great Pond, 2 m. long. The scenery is
picturesque and the township is much frequented by artists. Montauk
Lighthouse, on Turtle Hill, was first built in 1795. At Montauk, after
the Spanish-American War, was Camp Wikoff, a large U.S. military camp.
The township is served by the southern division of the Long Island
railway, the terminus of which is Montauk. Other villages of the
township, all summer resorts, are: Promised Land, Amagansett, East
Hampton and Sag Harbor; the last named, only partly in the township, was
incorporated in 1803 and had a population of 1969 in 1900, and 3084 in
1910. Silverware and watch cases are manufactured here. From Sag Harbor,
which is a port of entry, a daily steamer runs to New York city. The
village received many gifts in 1906-1908 from Mrs Russell Sage. Most of
the present township was bought from the Indians (Montauks, Corchaugs
and Shinnecocks) in 1648 for about £30, through the governors of
Connecticut and New Haven, by nine Massachusetts freemen, mostly
inhabitants of Lynn, Massachusetts. With twenty other families they
settled here in 1649, calling the place Maidstone, from the old home of
some of the settlers in Kent; but as early as 1650 the name East Hampton
was used in reference to the earlier settlement of South Hampton. Until
1664, when all Long Island passed to the duke of York, the government
was by town meeting, autonomous and independent except for occasional
appeals to Connecticut. In 1683 Gardiner's Island, settled by Lion
Gardiner in 1639 and so one of the first English settlements in what is
now New York state, was made a part of Long Island and of East Hampton
township. The English settlements in East Hampton were repeatedly
threatened by pirates and privateers, and there are many stories of
treasure buried by Captain Kidd on Gardiner's Island and on Montauk
Point. The Clinton Academy, opened in East Hampton village in 1785, was
long a famous school. Of the church built here in 1653 (first
Congregational and after 1747 Presbyterian in government), Lyman Beecher
was pastor in 1799-1810; and in East Hampton were born his elder
children. Whale fishing was begun in East Hampton in 1675, when four
Indians were engaged by whites in off-shore whaling; but Sag Harbor,
which was first settled in 1730 and was held by the British after the
battle of Long Island as a strategic naval and shipping point, became
the centre of the whaling business. The first successful whaling voyage
was made from Sag Harbor in 1785, and although the Embargo ruined the
fishing for a time, it revived during 1830-1850. Cod and menhaden
fishing, the latter for the manufacture of fish-oil and guano, were
important for a time, but in the second half of the 19th century Sag
Harbor lost its commercial importance.



EAST INDIA COMPANY, an incorporated company for exploiting the trade
with India and the Far East. In the 17th and 18th centuries East India
companies were established by England, Holland, France, Denmark,
Scotland, Spain, Austria and Sweden. By far the most important of these
was the English East India Company, which became the dominant power in
India, and only handed over its functions to the British Government in
1858 (see also DUTCH EAST INDIA COMPANY, OSTEND COMPANY).


  English East India Co.

The English East India Company was founded at the end of the 16th
century in order to compete with the Dutch merchants, who had obtained a
practical monopoly of the trade with the Spice Islands, and had raised
the price of pepper from 3s. to 8s. per lb. Queen Elizabeth incorporated
it by royal charter, dated December 31, 1600, under the title of "The
Governor and Company of Merchants of London, trading into the East
Indies." This charter conferred the sole right of trading with the East
Indies, i.e. with all countries lying beyond the Cape of Good Hope or
the Straits of Magellan, upon the company for a term of 15 years.
Unauthorized interlopers were liable to forfeiture of ships and cargo.
There were 125 shareholders in the original East India Company, with a
capital of £72,000: the first governor was Sir Thomas Smythe. The early
voyages of the company, from 1601 to 1612, are distinguished as the
"separate voyages," because the subscribers individually bore the cost
of each voyage and reaped the whole profits, which seldom fell below
100%. After 1612 the voyages were conducted on the joint stock system
for the benefit of the company as a whole. These early voyages, whose
own narratives may be read in Purchas, pushed as far as Japan, and
established friendly relations at the court of the Great Mogul. In
1610-1611 Captain Hippon planted the first English factories on the
mainland of India, at Masulipatam and at Pettapoli in the Bay of Bengal.
The profitable nature of the company's trade had induced James I. to
grant subsidiary licences to private traders; but in 1609 he renewed the
company's charter "for ever," though with a proviso that it might be
revoked on three years' notice if the trade should not prove profitable
to the realm.


  English and Dutch disputes.

Meanwhile friction was arising between the English and Dutch East India
Companies. The Dutch traders considered that they had prior rights in
the Far East, and their ascendancy in the Indian Archipelago was indeed
firmly established on the basis of territorial dominion and authority.
In 1613 they made advances to the English company with a suggestion for
co-operation, but the offer was declined, and the next few years were
fertile in disputes between the armed traders of both nations. In 1619
was ratified a "treaty of defence" to prevent disputes between the
English and Dutch companies. When it was proclaimed in the East,
hostilities solemnly ceased for the space of an hour, while the Dutch
and English fleets, dressed out in all their flags and with yards
manned, saluted each other; but the treaty ended in the smoke of that
stately salutation, and perpetual and fruitless contentions between the
Dutch and English companies went on just as before. In 1623 these
disputes culminated in the "massacre of Amboyna," where the Dutch
governor tortured and executed the English residents on a charge of
conspiring to seize the fort. Great and lasting indignation was aroused
in England, but it was not until the time of Cromwell that some
pecuniary reparation was exacted for the heirs of the victims. The
immediate result was that the English company tacitly admitted the Dutch
claims to a monopoly of the trade in the Far East, and confined their
operations to the mainland of India and the adjoining countries.


  The East Indiamen.

The necessity of good ships for the East Indian trade had led the
company in 1609 to construct their dockyard at Deptford, from which, as
Monson observes, dates "the increase of great ships in England." Down to
the middle of the 19th century, the famous "East Indiamen" held
unquestioned pre-eminence among the merchant vessels of the world.
Throughout the 17th century they had to be prepared at any moment to
fight not merely Malay pirates, but the armed trading vessels of their
Dutch, French and Portuguese rivals. Many such battles are recorded in
the history of the East India Company, and usually with successful
results.


  The acquisition of territory.

It was not until it had been in existence for more than a century that
the English East India Company obtained a practical monopoly of the
Indian trade. In 1635, a year after the Great Mogul had granted it the
liberty of trading throughout Bengal, Charles I. issued a licence to
Courten's rival association, known as "the Assada Merchants," on the
ground that the company had neglected English interests. The piratical
methods of their rivals disgraced the company with the Mogul officials,
and a _modus vivendi_ was only reached in 1649. In 1657 Cromwell renewed
the charter of 1609, providing that the Indian trade should be in the
hands of a single joint stock company. The new company thus formed
bought up the factories, forts and privileges of the old one. It was
further consolidated by the fostering care of Charles II., who granted
it five important charters. From a simple trading company, it grew under
his reign into a great chartered company--to use the modern term--with
the right to acquire territory, coin money, command fortresses and
troops, form alliances, make war and peace, and exercise both civil and
criminal jurisdiction. It is accordingly in 1689, when the three
presidencies of Bengal, Madras and Bombay had lately been established,
that the ruling career of the East India Company begins, with the
passing by its directors of the following resolution for the guidance of
the local governments in India:--"The increase of our revenue is the
subject of our care, as much as our trade; 'tis that must maintain our
force when twenty accidents may interrupt our trade; 'tis that must make
us a nation in India; without that we are but a great number of
interlopers, united by His Majesty's royal charter, fit only to trade
where nobody of power thinks it their interest to prevent us; and upon
this account it is that the wise Dutch, in all their general advices
that we have seen, write ten paragraphs concerning their government,
their civil and military policy, warfare, and the increase of their
revenue, for one paragraph they write concerning trade." From this
moment the history of the transactions of the East India Company becomes
the history of British India (see INDIA: _History_). Here we shall only
trace the later changes in the constitution and powers of the ruling
body itself.


  The interlopers.

The great prosperity of the company under the Restoration, and the
immense profits of the Indian trade, attracted a number of private
traders, both outside merchants and dismissed or retired servants of the
company, who came to be known as "interlopers." In 1683 the case of
Thomas Sandys, an interloper, raised the whole question of the royal
prerogative to create a monopoly of the Indian trade. The case was tried
by Judge Jeffreys, who upheld the royal prerogative; but in spite of his
decision the custom of interloping continued and laid the foundation of
many great fortunes. By 1691 the interlopers had formed themselves into
a new society, meeting at Dowgate, and rivalling the old company; the
case was carried before the House of Commons, which declared in 1694
that "all the subjects of England have equal right to trade to the East
Indies unless prohibited by act of parliament." This decision led up to
the act of 1698, which created a new East India Company in consideration
of a loan of two millions to the state. The old company subscribed
£315,000 and became the dominant factor in the new body; while at the
same time it retained its charter for three years, its factories, forts
and assured position in India. The rivalry between the two companies
continued both in England and in India, until they were finally
amalgamated by a tripartite indenture between the companies and Queen
Anne (1702), which was ratified under the Godolphin Award (1708). Under
this award the company was to lend the nation £3,200,000, and its
exclusive privileges were to cease at three years' notice after this
amount had been repaid. But by this time the need for permanence in the
Indian establishment began to be felt, while parliament would not
relinquish its privilege of "milking" the company from time to time. In
1712 an act was passed continuing the privileges of the company even
after their fund should be redeemed; in 1730 the charter was prolonged
until 1766, and in 1742 the term was extended until 1783 in return for
the loan of a million. This million was required for the war with
France, which extended to India and involved the English and French
companies there in long-drawn hostilities, in which the names of Dupleix
and Clive became prominent.


  The company and the crown.

So long as the company's chief business was that of trade, it was left
to manage its own affairs. The original charter of Elizabeth had placed
its control in the hands of a governor and a committee of twenty-four,
and this arrangement subsisted in essence down to the time of George
III. The chairman and court of directors in London exercised unchecked
control over their servants in India. But after Clive's brilliant
victory at Plassey (1757) had made the company a ruling power in India,
it was felt to be necessary that the British government should have some
control over the territories thus acquired. Lord North's Regulating Act
(1773) raised the governor of Bengal--Warren Hastings--to the rank of
governor-general, and provided that his nomination, though made by a
court of directors, should in future be subject to the approval of the
crown; in conjunction with a council of four, he was entrusted with the
power of peace and war; a supreme court of judicature was established,
to which the judges were appointed by the crown; and legislative power
was conferred on the governor-general and his council. Next followed
Pitt's India Bill (1784), which created the board of control, as a
department of the English government, to exercise political, military
and financial superintendence over the British possessions in India.
This bill first authorized the historic phrase "governor-general in
council." From this date the direction of Indian policy passed
definitely from the company to the governor-general in India and the
ministry in London. In 1813 Lord Liverpool passed a bill which further
gave the board of control authority over the company's commercial
transactions, and abolished its monopoly of Indian trade, whilst leaving
it the monopoly of the valuable trade with China, chiefly in tea.
Finally, under Earl Grey's act of 1833, the company was deprived of this
monopoly also. Its property was then secured on the Indian possessions,
and its annual dividends of ten guineas per £100 stock were made a
charge upon the Indian revenue. Henceforward the East India Company
ceased to be a trading concern and exercised only administrative
functions. Such a position could not, in the nature of things, be
permanent, and the great cataclysm of the Indian Mutiny was followed by
the entire transference of Indian administration from the company to the
crown, on the 2nd of August 1858.

  See _Purchas his Pilgrimes_ (ed. 1905), vols. 2, 3, 4, 5, for the
  charter of Elizabeth and the early voyages; Sir W.W. Hunter, _History
  of British India_ (1899); Beckles Willson, _Ledger and Sword_ (1903);
  Sir George Birdwood, _Report on the Old Records of the India Office_
  (1879); _The East India Company's First Letter Book_ (1895), _Letters
  Received by the East India Company from its Servants in the East_, ed.
  Foster, (1896 ff.). See also the interesting memorial volume _Relics
  of the Honourable East India Company_ (ed. Griggs, 1909), letterpress
  by Sir G. Birdwood and W. Foster.



EAST INDIES, a name formerly applied vaguely, in its widest sense, to
the whole area of India, Further India and the Malay Archipelago, in
distinction from the West Indies, which, at the time of their discovery,
were taken to be the extreme parts of the Indian region. The term "East
Indies" is still sometimes applied to the Malay Archipelago (q.v.)
alone, and the phrase "Dutch East Indies" is commonly used to denote the
Dutch possessions which constitute the greater part of that archipelago.
The Dutch themselves use the term _Nederlandsch-Indië_.



EASTLAKE, SIR CHARLES LOCK (1793-1865), English painter, was born on the
17th of November 1793 at Plymouth, where his father, a man of uncommon
gifts but of indolent temperament, was solicitor to the admiralty and
judge advocate of the admiralty court. Charles was educated (like Sir
Joshua Reynolds) at the Plympton grammar-school, and in London at the
Charterhouse. Towards 1809, partly through the influence of his
fellow-Devonian Haydon, of whom he became a pupil, he determined to be a
painter; he also studied in the Royal Academy school. In 1813 he
exhibited in the British Institution his first picture, a work of
considerable size, "Christ restoring life to the Daughter of Jairus." In
1814 he was commissioned to copy some of the paintings collected by
Napoleon in the Louvre; he returned to England in 1815, and practised
portrait-painting at Plymouth. Here he saw Napoleon a captive on the
"Bellerophon"; from a boat he made some sketches of the emperor, and he
afterwards painted, from these sketches and from memory, a life-sized
full-length portrait of him (with some of his officers) which was
pronounced a good likeness; it belongs to the marquess of Lansdowne. In
1817 Eastlake went to Italy; in 1819 to Greece; in 1820 back to Italy,
where he remained altogether fourteen years, chiefly in Rome and in
Ferrara.

In 1827 he exhibited at the Royal Academy his picture of the Spartan
Isidas, who (as narrated by Plutarch in the life of Agesilaus), rushing
naked out of his bath, performed prodigies of valour against the Theban
host. This was the first work that attracted much notice to the name of
Eastlake, who in consequence obtained his election as A.R.A.; in 1830,
when he returned to England, he was chosen R.A. In 1850 he succeeded
Shee as president of the Royal Academy, and was knighted. Prior to this,
in 1841, he had been appointed secretary to the royal commission for
decorating the Houses of Parliament, and he retained this post until the
commission was dissolved in 1862. In 1843 he was made keeper of the
National Gallery, a post which he resigned in 1847 in consequence of an
unfortunate purchase that roused much animadversion, a portrait
erroneously ascribed to Holbein; in 1855, director of the same
institution, with more extended powers. During his directorship he
purchased for the gallery 155 pictures, mostly of the Italian schools.
He became also a D.C.L. of Oxford, F.R.S., a chevalier of the Legion of
Honour, and member of various foreign academies.

In 1849 he married Miss Elizabeth Rigby, who had already then become
known as a writer (_Letters from the Baltic_, 1841; _Livonian Tales_,
1846; _The Jewess_, 1848) and as a contributor to the _Quarterly
Review_. Lady Eastlake (1809-1893) had for some years been interested in
art subjects, and after her marriage she naturally devoted more
attention to them, translating Waagen's _Treasures of Art in Great
Britain_ (1854-1857), and completing Mrs Jameson's _History of our Lord
in Works of Art_. In 1865 Sir Charles Eastlake fell ill at Milan; and he
died at Pisa on the 24th of December in the same year. Lady Eastlake,
who survived him for many years, continued to play an active part as a
writer on art (_Five Great Painters_, 1883, &c.), and had a large circle
of friends among the most interesting men and women of the day. In 1880
she published a volume of _Letters from France_ (describing events in
Paris during 1789), written by her father, Edward Rigby (1747-1821), a
distinguished Norwich doctor who was known also for his practical
interest in agriculture, and who is said to have made known the flying
shuttle to Norwich manufacturers.

As a painter, Sir Charles Eastlake was gentle, harmonious, diligent and
correct; lacking fire of invention or of execution; eclectic, without
being exactly imitative; influenced rather by a love of ideal grace and
beauty than by any marked bent of individual power or vigorous
originality. Among his principal works (which were not numerous, 51
being the total exhibited in the Academy) are: 1828, "Pilgrims arriving
in sight of Rome" (repeated in 1835 and 1836, and perhaps on the whole
his _chef-d'oeuvre_); 1829, "Byron's Dream" (in the Tate Gallery); 1834,
the "Escape of Francesco di Carrara" (a duplicate in the Tate Gallery);
1841, "Christ Lamenting over Jerusalem" (ditto); 1843, "Hagar and
Ishmael"; 1845, "Comus"; 1849, "Helena"; 1851, "Ippolita Torelli"; 1853,
"Violante"; 1855, "Beatrice." These female heads, of a refined
semi-ideal quality, with something of Venetian glow of tint, are the
most satisfactory specimens of Eastlake's work to an artist's eye. He
was an accomplished and judicious scholar in matters of art, and
published, in 1840, a translation of Goethe's _Theory of Colours_; in
1847 (his chief literary work) _Materials for a History of
Oil-Painting_, especially valuable as regards the Flemish school; in
1848, _Contributions to the Literature of the Fine Arts_ (a second
series was edited by Lady Eastlake in 1870, and accompanied by a Memoir
from her pen); in 1851 and 1855, translated editions of Kugler's
_History of the Italian School of Painting_, and _Handbook of Painting_
(new edition, by Lady Eastlake, 1874).

  See W. Cosmo Monkhouse, _Pictures by Sir Charles Eastlake, with
  biographical and critical Sketch_ (1875).     (W. M. R.)



EAST LIVERPOOL, a city of Columbiana county, Ohio, U.S.A., on the Ohio
river, about 106 m. S.E. of Cleveland. Pop. (1890) 10,956; (1900)
16,485, of whom 2112 were foreign-born; (1910 census) 20,357. It is
served by the Pennsylvania railway, by river steamboats, and by
interurban electric lines. Next to Trenton, New Jersey, East Liverpool
is the most important place in the United States for the manufacture of
earthenware and pottery, 4859 out of its 5228 wage-earners, or 92.9%,
being employed in this industry in 1905, when $5,373,852 (83.5% of the
value of all its factory products) was the value of the earthenware and
pottery. No other city in the United States is so exclusively devoted to
the manufacture of pottery; in 1908 there were 32 potteries in the city
and its immediate vicinity. The manufacture of white ware, begun in
1872, is the most important branch of the industry--almost half of the
"cream-coloured," white granite ware and semivitreous porcelain produced
in the United States in 1905 (in value, $4,344,468 out of $9,195,703)
being manufactured in East Liverpool. Though there are large clay
deposits in the vicinity, very little of it can be used for crockery,
and most of the clay used in the city's potteries is obtained from other
states; some of it is imported from Europe. After 1872 a large number of
skilled English pottery-workers settled in the city. The city's product
of pottery, terra-cotta and fireclay increased from $2,137,063 to
$4,105,200 from 1890 to 1900, and in the latter year almost equalled
that of Trenton, N.J., the two cities together producing more than half
(50.9%) of the total pottery product of the United States; in 1905 East
Liverpool and Trenton together produced 42.1% of the total value of the
country's pottery product. The municipality owns and operates its
water-works. East Liverpool was settled in 1798, and was incorporated in
1834.



EAST LONDON, a town of the Cape province, South Africa, at the mouth of
the Buffalo river, in 33° 1' S. 27° 55' E., 543 m. E.N.E. of Cape Town
by sea and 666 m. S. of Johannesburg by rail. Pop. (1904) 25,220, of
whom 14,674 were whites. The town is picturesquely situated on both
sides of the river, which is spanned by a combined road and railway
bridge. The railway terminus and business quarter are on the east side
on the top of the cliffs, which rise 150 ft. above the river. In Oxford
Street, the chief thoroughfare, is the town hall, a handsome building
erected in 1898. Higher up a number of churches and a school are
grouped round Vincent Square, a large open space. In consequence of the
excellent sea bathing, and the beauty of the river banks above the town,
East London is the chief seaside holiday resort of the Cape province.
The town is the entrepot of a rich agricultural district, including the
Transkei, Basutoland and the south of Orange Free State, and the port of
the Cape nearest Johannesburg. It ranks third among the ports of the
province. The roadstead is exposed and insecure, but the inner harbour,
constructed at a cost of over £2,000,000, is protected from all winds. A
shifting sand bar lies at the mouth of the river, but the building of
training walls and dredging have increased the minimum depth of water to
22 ft. From the east bank of the Buffalo a pier and from the west bank a
breakwater project into the Indian Ocean, the entrance being 450 ft.
wide, reduced between the training walls to 250 ft. There is extensive
wharf accommodation on both sides of the river, and steamers of over
8000 tons can moor alongside. There is a patent slip capable of taking
vessels of 1000 tons dead weight. An aerial steel ropeway from the river
bank to the town greatly facilitates the delivery of cargo. The imports
are chiefly textiles, hardware and provisions, the exports mainly wool
and mohair. The rateable value of the town in 1908 was £4,108,000, and
the municipal rate 1-5/8 d.

East London owes its foundation to the necessities of the Kaffir war of
1846-1847. The British, requiring a port nearer the scene of war than
those then existing, selected a site at the mouth of the Buffalo river,
and in 1847 the first cargo of military stores was landed. A fort, named
Glamorgan, was built, and the place permanently occupied. Around this
military post grew up the town, known at first as Port Rex. Numbers of
its inhabitants are descendants of German immigrants who settled in the
district in 1857. The prosperity of the town dates from the era of
railway and port development in the last decade of the 19th century. In
1875 the value of the exports was £131,803 and that of the imports
£552,033. In 1904 the value of the exports was £1,165,938 and that of
the imports £4,688,415. In 1907 the exports, notwithstanding a period of
severe trade depression, were valued at £1,475,355, but the imports had
fallen to £3,354,633.



EASTON, a city and the county-seat of Northampton county, Pennsylvania,
U.S.A., at the confluence of the Lehigh river and Bushkill Creek with
the Delaware, about 60 m. N. of Philadelphia. Pop. (1890) 14,481; (1900)
25,238, of whom 2135 were foreign-born; (1910 census) 28,523. Easton is
served by the Central of New Jersey, the Lehigh Valley, the Lehigh &
Hudson River and the Delaware, Lackawanna & Western railways, and is
connected by canals with the anthracite coal region to the north-west
and with Bristol, Pa. A bridge across the Delaware river connects it
with Phillipsburg, New Jersey, which is served by the Pennsylvania
railway. The city is built on rolling ground, commanding pleasant views
of hill and river scenery. Many fine residences overlook city and
country from the hillsides, and a Carnegie library is prominent among
the public buildings. Lafayette College, a Presbyterian institution
opened in 1832, is finely situated on a bluff north of the Bushkill and
Delaware. The college provides the following courses of instruction:
graduate, classical, Latin scientific, general scientific, civil
engineering, electrical engineering, mining engineering and chemical; in
1908 it had 38 instructors and 442 students, 256 of whom were enrolled
in the scientific and engineering courses. Overlooking the Bushkill is
the Easton Cemetery, in which is the grave of George Taylor (1716-1781),
a signer of the Declaration of Independence, with a monument of Italian
marble to his memory. Among the city's manufactures are silk, hosiery
and knit goods, flour, malt liquors, brick, tile, drills, lumber and
planing mill products and organs; in 1905 the value of all the factory
products was $5,654,594, of which $2,290,598, or 40.5%, was the value of
the silk manufactures. Easton is the commercial centre of an important
mining region, which produces, in particular, iron ore, soapstone,
cement, slate and building stone. The municipality owns and operates an
electric-lighting plant. Easton was a garden spot of the Indians, and
here, because they would not negotiate elsewhere, several important
treaties were made between 1756 and 1762 during the French and Indian
War. The place was laid out in 1752, and was made the county-seat of the
newly erected county. It was incorporated as a borough in 1789, received
a new borough charter in 1823, and in 1887 was chartered as a city.
South Easton was annexed in 1898.



EAST ORANGE, a city of Essex county, New Jersey, U.S.A., in the
north-eastern part of the state, adjoining the city of Newark, and about
12 m. W. of New York city. Pop. (1890) 13,282; (1900) 21,506, of whom
3950 were foreign-born and 1420 were negroes; (1910 census) 34,371. It
is served by the Morris & Essex division of the Delaware, Lackawanna &
Western railway and by the Orange branch of the Erie (the former having
four stations--Ampere, Grove Street, East Orange and Brick Church), and
is connected with Newark, Orange and West Orange by electric line. The
city covers an area of about 4 sq. m., and has broad, well-paved
streets, bordered with fine shade trees (under the jurisdiction of a
"Shade Tree Commission"). It is primarily a residential suburb of New
York and Newark, and has many beautiful homes; with Orange, West Orange
and South Orange it forms virtually one community, popularly known as
"the Oranges." The public school system is excellent, and the city has a
Carnegie library (1903), with more than 22,000 volumes in 1907. Among
the principal buildings are several attractive churches, the city hall,
and the club-house of the Woman's Club of Orange. The principal
manufactures of East Orange are electrical machinery, apparatus, and
supplies (the factory of the Crocker-Wheeler Co. being here--in a part
of the city known as "Ampere") and pharmaceutical materials. The total
value of the city's factory products in 1905 was $2,326,552. East Orange
has a fine water-works system, which it owns and operates; the water
supply is obtained from artesian wells at White Oaks Ridge, in the
township of Milburn (about 10 m. from the city hall); thence the water
is pumped to a steel reinforced reservoir (capacity 5,000,000 gallons)
on the mountain back of South Orange. In 1863 the township of East
Orange was separated from the township of Orange, which, in turn, had
been separated from the township of Newark in 1806. An act of the New
Jersey legislature in 1895 created the office of township president,
with power of appointment and veto. Four years later East Orange was
chartered as a city.

  See H. Whittemore, _The Founders and Builders of the Oranges_ (Newark,
  1896).



EASTPORT, a city and port of entry of Washington county, Maine, U.S.A.,
co-extensive with Moose Island in Passamaquoddy Bay, about 190 m. E.N.E.
of Portland. Pop. (1890) 4908; (1900) 5311 (1554 foreign-born); (1910)
4961. It is served by the Washington County railway, and by steamboat
lines to Boston, Portland and Calais. It is the most eastern city of the
United States, and is separated from the mainland by a narrow channel,
which is spanned by a bridge. The harbour is well protected from the
winds, and the tide, which rises and falls here about 25 ft., prevents
it from being obstructed with ice. The city is built on ground sloping
gently to the water's edge, and commands delightful views of the bay, in
which there are several islands. Its principal industry is the canning
of sardines; there are also clam canneries. Shoes, mustard, decorated
tin, and shooks are manufactured, and fish and lobsters are shipped from
here in the season. The city is the port of entry for the customs
district of Passamaquoddy; in 1908 its imports were valued at $994,961,
and its exports at $1,155,791. Eastport was first settled about 1782 by
fishermen; it became a port of entry in 1790, was incorporated as a town
in 1798, and was chartered as a city in 1893. It was a notorious place
for smuggling under the Embargo Acts of 1807 and 1808. On the 11th of
July 1814, during the war of 1812, it was taken by the British. As the
British government claimed the islands of Passamaquoddy Bay under the
treaty of 1783, the British forces retained possession of Eastport after
the close of the war and held it under martial law until July 1818, when
it was surrendered in accordance with the decision rendered in November
1817 by commissioners appointed under Article IV. of the treaty of Ghent
(1814), this decision awarding Moose Island, Dudley Island and Frederick
Island to the United States and the other islands, including the Island
of Grand Manan in the Bay of Fundy, to Great Britain.



EAST PROVIDENCE, a township of Providence county, Rhode Island, U.S.A.,
on the E. side of Providence river, opposite Providence. Pop. (1890)
8422; (1900) 12,138, of whom 2067 were foreign-born; (1910 census)
15,808. Area, 12½ sq. m. It is served by the New York, New Haven &
Hartford railway. It has a rolling surface and contains several
villages, one of which, known as Rumford, has important manufactories of
chemicals and electrical supplies. South of this village, along the
river bank, are several attractive summer resorts, Hunt's Mills, Silver
Spring, Riverside, Vanity Fair, Kettle Point and Bullock's Point being
prominent among them. In 1905 the factory products of the township were
valued at $5,035,288. The oyster trade is important. It was within the
present limits of this township that Roger Williams established himself
in the spring of 1636, until he learned that the place was within the
jurisdiction of the Plymouth Colony. About 1644 it was settled by a
company from Weymouth as a part of a town of Rehoboth. In 1812 Rehoboth
was divided, and the west part was made the township of Seekonk.
Finally, in 1861, it was decided that the west part of Seekonk belonged
to Rhode Island, and in the following year that part was incorporated as
the township of East Providence.



EAST PRUSSIA (_Ost-Preussen_), the easternmost province of the kingdom
of Prussia, bounded on the N. by the Baltic, on the E. and S.W. by
Russia and Russian Poland, and on the W. by the Prussian province of
West Prussia. It has an area of 14,284 sq. m., and had, in 1905, a
population of 2,025,741. It shares in the general characteristics of the
great north German plain, but, though low, its surface is by no means
absolutely flat, as the southern half is traversed by a low ridge or
plateau, which attains a height of 1025 ft. at a point near the western
boundary of the province. This plateau, here named the Prussian
Seenplatte, is thickly sprinkled with small lakes, among which is the
Spirding See, 46 sq. m. in extent and the largest inland lake in the
Prussian monarchy. The coast is lined with low dunes or sandhills, in
front of which lie the large littoral lakes or lagoons named the
Frisches Haff and the Kurisches Haff. The first of these receives the
waters of the Nogat and the Pregel, and the other those of the Memel or
Niemen. East Prussia is the coldest part of Germany, its mean annual
temperature being about 44° F., while the mean January temperature of
Tilsit is only 25°. The rainfall is 24 in. per annum. About half the
province is under tillage; 18% is occupied by forests, and about 23% by
meadows and pastures. The most fertile soil is found in the valleys of
the Pregel and the Memel, but the southern slopes of the Baltic plateau
and the district to the north of the Memel consist in great part of
sterile moor, sand and bog. The chief crops are rye, oats and potatoes,
while flax is cultivated in the district of Ermeland, between the
Passarge and the upper Alle. East Prussia is the headquarters of the
horse-breeding of the country, and contains the principal government
stud of Trakehnen; numerous cattle are also fattened on the rich
pastures of the river-valleys. The extensive woods in the south part of
the province harbour a few wolves and lynxes, and the elk is still
preserved in the forest of Ibenhorst, near the Kurisches Haff. The
fisheries in the lakes and haffs are of some importance; but the only
mineral product of note is amber, which is found in the peninsula of
Samland in greater abundance than in any other part of the world.
Manufactures are almost confined to the principal towns, though
linen-weaving is practised as a domestic industry. Commerce is
facilitated by canals connecting the Memel and Pregel and also the
principal lakes, but is somewhat hampered by the heavy dues exacted at
the Russian frontier. A brisk foreign trade is carried on through the
seaports of Königsberg, the capital of the province, and Memel, the
exports consisting mainly of timber and grain.

The population of the province was in 1900 1,996,626, and included
1,698,465 Protestants, 269,196 Roman Catholics and 13,877 Jews. The
Roman Catholics are mainly confined to the district of Ermeland, in
which the ordinary proportions of the confessions are completely
reversed. The bulk of the inhabitants are of German blood, but there are
above 400,000 Protestant Poles (Masurians or Masovians) in the south
part of the province, and 175,000 Lithuanians in the north. As in other
provinces where the Polish element is strong, East Prussia is somewhat
below the general average of the kingdom in education. There is a
university at Königsberg.

  See Lohmeyer, _Geschichte von Ost- und West-Preussen_ (Gotha, 1884);
  Brünneck, _Zur Geschichte des Kirchen-Patronats in Ost- und
  West-Preussen_ (Berlin, 1902), and _Ost-Preussen, Land und Volk_
  (Stuttgart, 1901-1902).



EASTWICK, EDWARD BACKHOUSE (1814-1883), British Orientalist, was born in
1814, a member of an Anglo-Indian family. Educated at Charterhouse and
at Oxford, he joined the Bombay infantry in 1836, but, owing to his
talent for languages, was soon given a political post. In 1843 he
translated the Persian _Kessahi Sanján_, or _History of the Arrival of
the Parsees in India_; and he wrote a _Life of Zoroaster_, a _Sindhi_
vocabulary, and various papers in the transactions of the Bombay Asiatic
Society. Compelled by ill-health to return to Europe, he went to
Frankfort, where he learned German and translated Schiller's _Revolt of
the Netherlands_ and Bopp's _Comparative Grammar_. In 1845 he was
appointed professor of Hindustani at Haileybury College. Two years later
he published a Hindustani grammar, and, in subsequent years, a new
edition of the _Gulistán_, with a translation in prose and verse, also
an edition with vocabulary of the Hindi translation by Lallú Lál of
Chatur Chuj Misr's _Prem Sagár_, and translations of the _Bagh-o-Bahar_,
and of the _Anvár-i Suhaili_ of Bídpáí. In 1851 he was elected a Fellow
of the Royal Society. In 1857-1858 he edited _The Autobiography of
Lútfullah_. He also edited for the Bible Society the Book of Genesis in
the Dakhani language. From 1860 to 1863 he was in Persia as secretary to
the British Legation, publishing on his return _The Journal of a
Diplomate_. In 1866 he became private secretary to the secretary of
state for India, Lord Cranborne (afterwards marquess of Salisbury), and
in 1867 went, as in 1864, on a government mission to Venezuela. On his
return he wrote, at the request of Charles Dickens, for _All the Year
Round_, "Sketches of Life in a South American Republic." From 1868 to
1874 he was M.P. for Penryn and Falmouth. In 1875 he received the degree
of M.A. with the franchise from the university of Oxford, "as a slight
recognition of distinguished services." At various times he wrote
several of Murray's Indian hand-books. His last work was the
_Kaisarnamah-i-Hind_ ("the lay of the empress"), in two volumes
(1878-1882). He died at Ventnor, Isle of Wight, on the 16th of July
1883.



EATON, DORMAN BRIDGMAN (1823-1899), American lawyer, was born at
Hardwick, Vermont, on the 27th of June 1823. He graduated at the
university of Vermont in 1848 and at the Harvard Law School in 1850, and
in the latter year was admitted to the bar in New York city. There he
became associated in practice with William Kent, the son of the great
chancellor, an edition of whose _Commentaries_ he assisted in editing.
Eaton early became interested in municipal and civil service reform. He
was conspicuous in the fight against Tweed and his followers, by one of
whom he was assaulted; he required a long period of rest, and went to
Europe, where he studied the workings of the civil service in various
countries. From 1873 to 1875 he was a member of the first United States
Civil Service Commission. In 1877, at the request of President Hayes, he
made a careful study of the British civil service, and three years later
published _Civil Service in Great Britain_. He drafted the Pendleton
Civil Service Act of 1883, and later became a member of the new
commission established by it. He resigned in 1885, but was almost
immediately reappointed by President Cleveland, and served until 1886,
editing the 3rd and 4th _Reports_ of the commission. He was an organizer
(1878) of the first society for the furtherance of civil service reform
in New York, of the National Civil Service Reform Association, and of
the National Conference of the Unitarian Church (1865). He died in New
York city on the 23rd of December 1899, leaving $100,000 each to Harvard
and Columbia universities for the establishments of professorships in
government. He was a legal writer and editor, and a frequent contributor
to the leading reviews. In addition to the works mentioned he published
_Should Judges be Elected?_ (1873), _The Independent Movement in New
York_ (1880), _Term and Tenure of Office_ (1882), _The Spoils System and
Civil Service Reform_ (1882), _Problems of Police Legislation_ (1895)
and _The Government of Municipalities_ (1899).

  See the privately printed memorial volume, _Dorman B. Eaton_,
  1823-1899 (New York, 1900).



EATON, MARGARET O'NEILL (1796-1879), better known as PEGGY O'NEILL, was
the daughter of the keeper of a popular Washington tavern, and was noted
for her beauty, wit and vivacity. About 1823, she married a purser in
the United States navy, John B. Timberlake, who committed suicide while
on service in the Mediterranean in 1828. In the following year she
married John Henry Eaton (1790-1856), a Tennessee politician, at the
time a member of the United States Senate. Senator Eaton was a close
personal friend of President Jackson, who in 1829 appointed him
secretary of war. This sudden elevation of Mrs Eaton into the cabinet
social circle was resented by the wives of several of Jackson's
secretaries, and charges were made against her of improper conduct with
Eaton previous to her marriage to him. The refusal of the wives of the
cabinet members to recognize the wife of his friend angered President
Jackson, and he tried in vain to coerce them. Eventually, and partly for
this reason, he almost completely reorganized his cabinet. The effect of
the incident on the political fortunes of the vice-president, John C.
Calhoun, whose wife was one of the recalcitrants, was perhaps most
important. Partly on this account, Jackson's favour was transferred from
Calhoun to Martin Van Buren, the secretary of state, who had taken
Jackson's side in the quarrel and had shown marked attention to Mrs
Eaton, and whose subsequent elevation to the vice-presidency and
presidency through Jackson's favour is no doubt partly attributable to
this incident. In 1836 Mrs Eaton accompanied her husband to Spain, where
he was United States minister in 1836-1840. After the death of her
husband she married a young Italian dancing-master, Antonio Buchignani,
but soon obtained a divorce from him. She died in Washington on the 8th
of November 1879.

  See James Parton's _Life of Andrew Jackson_ (New York, 1860).



EATON, THEOPHILUS (c. 1590-1658), English colonial governor in America,
was born at Stony Stratford, Buckinghamshire, about 1590. He was
educated in Coventry, became a successful merchant, travelled widely
throughout Europe, and for several years was the financial agent of
Charles I. in Denmark. He subsequently settled in London, where he
joined the Puritan congregation of the Rev. John Davenport, whom he had
known since boyhood. The pressure upon the Puritans increasing, Eaton,
who had been one of the original patentees of the Massachusetts Bay
colony in 1629, determined to use his influence and fortune to establish
an independent colony of which his pastor should be the head. In 1637 he
emigrated with Davenport to Massachusetts, and in the following year
(March 1638) he and Davenport founded New Haven. In October 1639 a form
of government was adopted, based on the Mosaic Law, and Eaton was
elected governor, a post which he continued to hold by annual
re-election, first over New Haven alone, and after 1643 over the New
Haven Colony or Jurisdiction, until his death at New Haven on the 7th of
January 1658. His administration was embarrassed by constantly recurring
disputes with the neighbouring Dutch settlements, especially after
Stamford (Conn.) and Southold (Long Island) had entered the New Haven
Jurisdiction, but his prudence and diplomacy prevented an actual
outbreak of hostilities. He was prominent in the affairs of the New
England Confederation, of which he was one of the founders (1643). In
1655 he and Davenport drew up the code of laws, popularly known as the
"Connecticut Blue Laws," which were published in London in 1656 under
the title _New Haven's Settling in New England and some Lawes for
Government published for the Use of that Colony_.

  A sketch of his life appears in Cotton Mather's _Magnalia_ (London,
  1702); see also J.B. Moore's "Memoir of Theophilus Eaton" in the
  _Collections_ of the New York Historical Society, second series, vol.
  ii. (New York, 1849).



EATON, WILLIAM (1764-1811), American soldier, was born in Woodstock,
Connecticut, on the 23rd of February 1764. As a boy he served for a
short time in the Continental army. He was a school teacher for several
years, graduated at Dartmouth College in 1790, was clerk of the lower
house of the Vermont legislature in 1791-1792, and in 1792 re-entered
the army as a captain, later serving against the Indians in Ohio and
Georgia. In 1797 he was appointed consul to Tunis, where he arrived in
February 1799. In March 1799, with the consuls to Tripoli and Algiers,
he negotiated alterations in the treaty of 1797 with Tunis. He rendered
great service to Danish merchantmen by buying on credit several Danish
prizes in Tunis and turning them over to their original owners for the
redemption of his notes. In 1803 he quarrelled with the Bey, was ordered
from the country, and returned to the United States to urge American
intervention for the restoration of Ahmet Karamanli to the throne of
Tripoli, arguing that this would impress the Barbary States with the
power of the United States. In 1804 he returned to the Mediterranean as
United States naval agent to the Barbary States with Barron's fleet. On
the 23rd of February 1805 he agreed with Ahmet that the United States
should undertake to re-establish him in Tripoli, that the expenses of
the expedition should be repaid to the United States by Ahmet, and that
Eaton should be general and commander-in-chief of the land forces in
Ahmet's campaign; as the secretary of the navy had given the entire
matter into the hands of Commodore Barron, and as Barron and Tobias Lear
(1762-1816), the United States consul-general at Algiers and a
diplomatic agent to conduct negotiations, had been instructed to
consider the advisability of making arrangements with the existing
government in Tripoli, Eaton far exceeded his authority. On the 8th of
March he started for Derna across the Libyan desert from the Arab's
Tower, 40 m. W. of Alexandria, with a force of about 500 men, including
a few Americans, about 40 Greeks and some Arab cavalry. In the march of
nearly 600 m. the camel-drivers and the Arab chiefs repeatedly mutinied,
and Ahmet Pasha once put himself at the head of the Arabs and ordered
them to attack Eaton. Ahmet more than once wished to give up the
expedition. There were practically no provisions for the latter part of
the march. On the 27th of April with the assistance of three bombarding
cruisers Eaton captured Derna--an exploit commemorated by Whittier's
poem _Derne_. On the 13th of May and on the 10th of June he successfully
withstood the attacks of Tripolitan forces sent to dislodge him. On the
12th of June he abandoned the town upon orders from Commodore Rodgers,
for Lear had made peace (4th June) with Yussuf, the _de facto_ Pasha of
Tripoli. Eaton returned to the United States, and received a grant of
10,000 acres in Maine from the Massachusetts legislature. According to a
deposition which he made in January 1807 he was approached by Aaron Burr
(q.v.), who attempted to enlist him in his "conspiracy," and wished him
to win over the marine corps and to sound Preble and Decatur. As he
received from the government, soon after making this deposition, about
$10,000 to liquidate claims for his expense in Tripoli, which he had
long pressed in vain, his good faith has been doubted. At Burr's trial
at Richmond in 1807 Eaton was one of the witnesses, but his testimony
was unimportant. In May 1807 he was elected a member of the
Massachusetts House of Representatives, and served for one term. He died
on the 1st of June 1811 in Brimfield, Massachusetts.

  See the anonymously published _Life of the Late Gen. William Eaton_
  (Brookfield, Massachusetts, 1813) by Charles Prentiss; C.C. Felton,
  "Life of William Eaton" in Sparks's _Library of American Biography_,
  vol. ix. (Boston, 1838); and Gardner W. Allen's _Our Navy and the
  Barbary Corsairs_ (Boston, 1905).



EATON, WYATT (1849-1896), American portrait and figure painter, was born
at Philipsburg, Canada, on the 6th of May 1849. He was a pupil of the
schools of the National Academy of Design, New York, and in 1872 went to
Paris, where he studied in the École des Beaux-Arts under J.L. Gérôme.
He made the acquaintance of J.F. Millet at Barbizon, and was also
influenced by his friend Jules Bastien-Lepage. After his return to the
United States in 1876 he became a teacher in Cooper Institute and opened
a studio in New York city. He was one of the organizers (and the first
secretary) of the Society of American Artists. Among his portraits are
those of William Cullen Bryant and Timothy Cole, the wood engraver ("The
Man with the Violin"). Eaton died at Newport, Rhode Island, on the 7th
of June 1896.



EAU CLAIRE, a city and the county-seat of Eau Claire county, Wisconsin,
U.S.A., on the Chippewa river, at the mouth of the Eau Claire, about 87
m. E. of St Paul. Pop. (1890) 17,415; (1900) 17,517, of whom 4996 were
foreign-born; (1910 census) 18,310. It is served by the Chicago &
North-Western, the Chicago, Milwaukee & St Paul, and the Wisconsin
Central railways, and is connected by an electric line with Chippewa
Falls (12 m. distant). The city has a Carnegie library with 17,200
volumes in 1908, a Federal building, county court house, normal school
and insane asylum. It has abundant water-power, and is an important
lumber manufacturing centre; among its other manufactures are flour,
wooden-ware, agricultural machinery, saw-mill machinery, logging
locomotives, wood pulp, paper, linen, mattresses, shoes and trunks. The
total value of factory products in 1905 was $3,601,558. The city is the
principal wholesale and jobbing market for the prosperous Chippewa
Valley. Eau Claire was first settled about 1847, and was chartered as a
city in 1872; its growth dates from the development of the north-western
lumber trade in the decade 1870-1880. In 1881 a serious strike
necessitated the calling out of state militia for its suppression and
the protection of property.



EAU DE COLOGNE (Ger. _Kölnisches Wasser_, "Cologne water"), a perfume,
so named from the city of Cologne, where its manufacture was first
established by an Italian, Johann (or Giovanni) Maria Farina
(1685-1766), who settled at Cologne in 1709. The perfume gained a high
reputation by 1766, and Farina associated himself with his nephew, to
whose grandson the secret was ultimately imparted; the original perfume
is still manufactured by members of this family under the name of the
founder. The manufacture is, however, carried on at Cologne, and also in
Italy, by other firms bearing the name Farina, and the scent has become
part of the regular output of perfumers. The discovery has also been
ascribed to a Paul de Feminis, who is supposed to have brought his
recipe from Milan to Cologne, of which he became a citizen in 1690, and
sold the perfume under the name _Eau admirable_, leaving the secret at
his death to his nephew Johann Maria Farina. Certain of the Farinas
claim to use his process. It was originally prepared by making an
alcoholic infusion of certain flowers, pot-herbs, drugs and spices,
distilling and then adding definite quantities of several vegetable
essences. The purity and thorough blending of the ingredients are of the
greatest importance. The original perfume is simulated and even excelled
by artificial preparations. The oils of lemon, bergamot and orange are
employed, together with the oils of neroli and rosemary in the better
class. The common practice consists in dissolving the oils, in certain
definite proportions based on experience, in pure alcohol and
distilling, the distillate being diluted by rose-water.



EAUX-BONNES, a watering-place of south-western France, in the department
of Basses-Pyrénées, 3½ m. S.E. of the small town of Laruns, the latter
being 24 m. S. of Pau by rail. Pop. (1906) 610. Eaux-Bonnes is situated
at a height of 2460 ft. at the entrance of a fine gorge, overlooking the
confluence of two torrents, the Valentin and the Sourde. The village is
well known for its sulphurous and saline mineral waters (first mentioned
in the middle of the 14th century), which are beneficial in affections
of the throat and lungs. They vary between 50° and 90° F. in
temperature, and are used for drinking and bathing. There are two
thermal establishments, a casino and fine promenades.

The watering-place of LES EAUX-CHAUDES is 5 m. by road south-west of
Eaux-Bonnes, in a wild gorge on the Gave d'Ossau. The springs are
sulphurous, varying in temperature from 52° to 97° F., and are used in
cases of rheumatism, certain maladies of women, &c. The thermal
establishment is a handsome marble building.

There is fine mountain scenery in the neighbourhood of both places, the
Pic de Ger near Eaux-Bonnes, commanding an extensive view. The valley of
Ossau, one of the most beautiful in the Pyrenees, before the Revolution
formed a community which, though dependent on Béarn, had its own legal
organization, manners and costumes, the last of which are still to be
seen on holidays.



EAVES (not a plural form as is sometimes supposed, but singular; O. Eng.
_efes_, in Mid. High Ger. _obse_, Gothic _ubizwa_, a porch; connected
with "over"), in architecture, the projecting edge of a sloping roof,
which overhangs the face of the wall so as to throw off the water.



EAVESDRIP, or EAVESDROP, that width of ground around a house or building
which receives the rain water dropping from the eaves. By an ancient
Saxon law, a landowner was forbidden to erect any building at less than
2 ft. from the boundary of his land, and was thus prevented from
injuring his neighbour's house or property by the dripping of water from
his eaves. The law of Eavesdrip has had its equivalent in the Roman
_stillicidium_, which prohibited building up to the very edge of an
estate.

From the Saxon custom arose the term "eavesdropper," i.e. any one who
stands within "the eavesdrop" of a house, hence one who pries into
others' business or listens to secrets. At common law an eavesdropper
was regarded as a common nuisance, and was presentable at the court
leet, and indictable at the sheriff's tourn and punishable by fine and
finding sureties for good behaviour. Though the offence of eavesdropping
still exists at common law, there is no modern instance of a prosecution
or indictment.



EBBW VALE, an urban district in the western parliamentary division of
Monmouthshire, England, 21 m. N.W. of Newport on the Great Western,
London & North-Western and Rhymney railways. Pop. (1891) 17,312; (1901)
20,994. It lies near the head of the valley of the river Ebbw, at an
elevation of nearly 1000 ft., in a wild and mountainous mining district,
which contains large collieries and important iron and steel works.



EBEL, HERMANN WILHELM (1820-1875), German philologist, was born at
Berlin on the 10th of May 1820. He displayed in his early years a
remarkable capacity for the study of languages, and at the same time a
passionate fondness for music and poetry. At the age of sixteen he
became a student at the university of Berlin, applying himself
especially to philology, and attending the lectures of Böckh. Music
continued to be the favourite occupation of his leisure hours, and he
pursued the study of it under the direction of Marx. In the spring of
1838 he passed to the university of Halle, and there began to apply
himself to comparative philology under Pott. Returning in the following
year to his native city, he continued this study as a disciple of Bopp.
He took his degree in 1842, and, after spending his year of probation at
the French Gymnasium of Berlin, he resumed with great earnestness his
language studies. About 1847 he began to study Old Persian. In 1852 he
accepted a professorship at the Beheim-Schwarzbach Institution at
Filehne, which post he held for six years. It was during this period
that his studies in the Old Slavic and Celtic languages began. In 1858
he removed to Schneidemühl, and there he discharged the duties of first
professor for ten years. He was afterwards called to the chair of
comparative philology at the university of Berlin. He died at Misdroy on
the 19th of August 1875. The most important work of Dr Ebel in the field
of Celtic philology is his revised edition of the _Grammatica Celtica_
of Professor Zeuss, completed in 1871. This had been preceded by his
treatises--_De verbi Britannici futuro ac conjunctivo_ (1866), and _De
Zeussii curis positis in Grammatica Celtica_ (1869). He made many
learned contributions to Kühn's _Zeitschrift für vergleichende
Sprachforschung_, and to A. Schleicher's _Beiträge zur vergleichenden
Sprachforschung_; and a selection of these contributions was translated
into English by Sullivan, and published under the title of _Celtic
Studies_ (1863). Ebel contributed the Old Irish section to Schleicher's
_Indogermanische Chrestomathie_ (1869). Among his other works must be
named _Die Lehnwörter der deutschen Sprache_ (1856).



EBEL, JOHANN GOTTFRIED (1764-1830), the author of the first real
guide-book to Switzerland, was born at Züllichau (Prussia). He became a
medical man, visited Switzerland for the first time in 1790, and became
so enamoured of it that he spent three years exploring the country and
collecting all kinds of information relating to it. The result was the
publication (Zürich, 1793) of his _Anleitung auf die nützlichste und
genussvollste Art in der Schweitz zu reisen_ (2 vols.), in which he gave
a complete account of the country, the General Information sections
being followed by an alphabetically arranged list of places, with
descriptions. It at once superseded all other works of the kind, and was
the best Swiss guide-book till the appearance of "Murray" (1838). It was
particularly strong on the geological and historical sides. The second
(1804-1805) and third (1809-1810) editions filled four volumes, but the
following (the 8th appeared in 1843) were in a single volume. The work
was translated into French in 1795 (many later editions) and into
English (by 1818). Ebel also published a work (2 vols., Leipzig,
1798-1802) entitled _Schilderungen der Gebirgsvölker der Schweiz_, which
deals mainly with the pastoral cantons of Glarus and Appenzell. In 1801
he was naturalized a Swiss citizen, and settled down in Zürich. In 1808
he issued his chief geological work, _Über den Bau der Erde im
Alpengebirge_ (Zürich, 2 vols.). He took an active share in promoting
all that could make his adopted country better known, e.g. Heinrich
Keller's map (1813), the building of a hotel on the Rigi (1816), and the
preparation of a panorama from that point (1823). From 1810 onwards he
lived at Zürich, with the family of his friend, Conrad Escher von der
Linth (1767-1823), the celebrated engineer.     (W. A. B. C.)



EBER, PAUL (1511-1569), German theologian, was born at Kitzingen in
Franconia, and was educated at Nuremberg and Wittenberg, where he became
the close friend of Philip Melanchthon. In 1541 he was appointed
professor of Latin grammar at Wittenberg, and in 1557 professor of the
Old Testament. His range of learning was wide, and he published a
handbook of Jewish history, a historical calendar intended to supersede
the Roman Saints' Calendar, and a revision of the Latin Old Testament.
In the theological conflict of the time he played a large part, doing
what he could to mediate between the extremists. From 1559 to the close
of his life he was superintendent-general of the electorate of Saxony.
He attained some fame as a hymn-writer, his best-known composition being
"Wenn wir in höchsten Nöthen sein." He died at Wittenberg on the 10th of
December 1569.



EBERBACH, a town of Germany, in the grand-duchy of Baden, romantically
situated on the Neckar, at the foot of the Katzenbuckel, 19 m. E. of
Heidelberg by the railway to Würzburg. Pop. (1900) 5857. It contains an
Evangelical and a Roman Catholic church, a commercial and a technical
school, and, in addition to manufacturing cigars, leather and cutlery,
carries on by water an active trade in timber and wine. Eberbach was
founded in 1227 by the German king Henry VII., who acquired the castle
(the ruins of which overhang the town) from the bishop of Worms. It
became an imperial town and passed later to the Palatinate.

  See Wirth, _Geschichte der Stadt Eberbach_ (Stuttgart, 1864).



EBERBACH, a famous Cistercian monastery of Germany, in the Prussian
province of Hesse-Nassau, situated near Hattenheim in the Rheingau, 10
m. N.W. from Wiesbaden. Founded in 1116 by Archbishop Adalbert of Mainz,
as a house of Augustinian canons regular, it was bestowed by him in 1131
upon the Benedictines, but was shortly afterwards repurchased and
conferred upon the Cistercian order. The Romanesque church (consecrated
in 1186) contains numerous interesting monuments and tombs, notable
among them being those of the archbishop of Mainz, Gerlach (d. 1371)
and Adolph II. of Nassau (d. 1475). It was despoiled during the Thirty
Years' War, was secularized in 1803, and now serves as a house of
correction. Its cellars contain some of the finest vintages of the Rhine
wines of the locality.

  See Bär, _Diplomatische Geschichte der Abtei Eberbach_ (Wiesb.,
  1851-1858 and 1886, 3 vols.), and Schäfer, _Die Abtei Eberbach im
  Mittelalter_ (Berlin, 1901).



EBERHARD, surnamed IM BART (_Barbatus_), count and afterwards duke of
Württemberg (1445-1496), was the second son of Louis I., count of
Württemberg-Urach (d. 1450), and succeeded his elder brother Louis II.
in 1457. His uncle Ulrich V., count of Württemberg-Stuttgart (d. 1480),
acted as his guardian, but in 1459, assisted by Frederick I., elector
palatine, he threw off this restraint, and undertook the government of
the district of Urach as Count Eberhard V. He neglected his duties as a
ruler and lived a reckless life until 1468, when he made a pilgrimage to
Jerusalem. He visited Italy, became acquainted with some famous
scholars, and in 1474 married Barbara di Gonzaga, daughter of Lodovico
III., marquis of Mantua, a lady distinguished for her intellectual
qualities. In 1482 he brought about the treaty of Münsingen with his
cousin Eberhard VI., count of Württemberg-Stuttgart. By this treaty the
districts of Urach and Stuttgart into which Württemberg had been divided
in 1437 were again united, and for the future the county was declared
indivisible, and the right of primogeniture established. The treaty led
to some disturbances, but in 1492 the sanction of the nobles was secured
for its provisions. In return for this Eberhard agreed to some
limitations on the power of the count, and so in a sense founded the
constitution of Württemberg. At the diet of Worms in 1495 the emperor
Maximilian I. guaranteed the treaty, confirmed the possessions and
prerogatives of the house of Württemberg, and raised Eberhard to the
rank of duke. Eberhard, although a lover of peace, was one of the
founders of the Swabian League in 1488, and assisted to release
Maximilian, then king of the Romans, from his imprisonment at Bruges in
the same year. He gave charters to the towns of Stuttgart and Tübingen,
and introduced order into the convents of his land, some of which he
secularized. He took a keen interest in the new learning, founded the
university of Tübingen in 1476, befriended John Reuchlin, whom he made
his private secretary, welcomed scholars to his court, and is said to
have learned Latin in later life. In 1482 he again visited Italy and
received the Golden Rose from Pope Sixtus IV. He won the esteem of the
emperors Frederick III. and Maximilian I. on account of his wisdom and
fidelity, and his people held him in high regard. His later years were
mainly spent at Stuttgart, but he died at Tübingen on the 25th of
February 1496, and in 1537 his ashes were placed in the choir of the
Stiftskirche there. Eberhard left no children, and the succession passed
to his cousin Eberhard, who became Duke Eberhard II.

  See Rösslin, _Leben Eberhards im Barte_ (Tübingen, 1793); Bossert,
  _Eberhard im Bart_ (Stuttgart, 1884).



EBERHARD, CHRISTIAN AUGUST GOTTLOB (1769-1845), German miscellaneous
writer, was born at Belzig, near Wittenberg, on the 12th of January
1769. He studied theology at Leipzig; but, a story he contributed to a
periodical having proved successful, he devoted himself to literature.
With the exception of _Hannchen und die Küchlein_ (1822), a narrative
poem in ten parts, and an epic on the Creation, _Der erste Mensch und
die Erde_ (1828), Eberhard's work was ephemeral in character and is now
forgotten. He died at Dresden on the 13th of May 1845.

  His collected works (_Gesammelte Schriften_) appeared in 20 volumes in
  1830-1831.



EBERHARD, JOHANN AUGUSTUS (1739-1809), German theologian and
philosopher, was born at Halberstadt in Lower Saxony, where his father
was singing-master at the church of St Martin's, and teacher of the
school of the same name. He studied theology at the university of Halle,
and became tutor to the eldest son of the baron von der Horst, to whose
family he attached himself for a number of years. In 1763 he was
appointed con-rector of the school of St Martin's, and second preacher
in the hospital church of the Holy Ghost; but he soon afterwards
resigned these offices and followed his patron to Berlin. There he met
Nicolai and Moses Mendelssohn, with whom he formed a close friendship.
In 1768 he became preacher or chaplain to the workhouse at Berlin and
the neighbouring fishing village of Stralow. Here he wrote his _Neue
Apologie des Socrates_ (1772), a work occasioned by an attack on the
fifteenth chapter of Marmontel's _Belisarius_ made by Peter Hofstede, a
clergyman of Rotterdam, who maintained the patristic view that the
virtues of the noblest pagans were only _splendida peccata_. Eberhard
stated the arguments for the broader view with dignity, acuteness and
learning, but the liberality of the reasoning gave great offence to the
strictly orthodox divines, and is believed to have obstructed his
preferment in the church.

In 1774 he was appointed to the living of Charlottenburg. A second
volume of his _Apologie_ appeared in 1778. In this he not only
endeavoured to obviate some objections which were taken to the former
part, but continued his inquiries into the doctrines of the Christian
religion, religious toleration and the proper rules for interpreting the
Scriptures. In 1778 he accepted the professorship of philosophy at
Halle. As an academical teacher, however, he was unsuccessful. His
powers as an original thinker were not equal to his learning and his
literary gifts, as was shown in his opposition to the philosophy of
Kant. In 1786 he was admitted a member of the Berlin Academy of
Sciences; in 1805 the king of Prussia conferred upon him the honorary
title of a privy-councillor. In 1808 he obtained the degree of doctor in
divinity, which was given him as a reward for his theological writings.
He died on the 6th of January 1809. He was master of the learned
languages, spoke and wrote French with facility and correctness, and
understood English, Italian and Dutch. He possessed a just and
discriminating taste for the fine arts, and was a great lover of music.

  Works:--_Neue Apologie des Socrates_, &c. (2 vols., 1772-1778);
  _Allgemeine Theorie des Denkens und Empfindens_, &c. (Berlin, 1776),
  an essay which gained the prize assigned by the Royal Society of
  Berlin for that year; _Von dem Begriff der Philosophie und ihren
  Theilen_ (Berlin, 1778)--a short essay, in which he announced the plan
  of his lectures on being appointed to the professorship at Halle;
  _Lobschrift auf Herrn Johann Thunmann Prof. der Weltweisheit und
  Beredsamkeit auf der Universität zu Halle_ (Halle, 1779); _Amyntor,
  eine Geschichte in Briefen_ (Berlin, 1782)--written with the view of
  counteracting the influence of those sceptical and Epicurean
  principles in religion and morals then so prevalent in France, and
  rapidly spreading amongst the higher ranks in Germany; _Über die
  Zeichen der Aufklärung einer Nation_, &c. (Halle, 1783); _Theorie der
  schönen Künste und Wissenschaften_, &c. (Halle, 1783, 3rd ed. 1790);
  _Vermischte Schriften_ (Halle, 1784); _Neue vermischte Schriften_ (ib.
  1786); _Allgemeine Geschichte der Philosophie_, &c. (Halle, 1788), 2nd
  ed. with a continuation and chronological tables (1796); _Versuch
  einer allgemeinen-deutschen Synonymik_ (Halle and Leipzig, 1795-1802,
  6 vols., 4th ed. 1852-1853), long reckoned the best work on the
  synonyms of the German language (an abridgment of it was published by
  the author in one large volume, Halle, 1802); _Handbuch der Aesthetik_
  (Halle, 1803-1805, 2nd ed. 1807-1820). He also edited the
  _Philosophisches Magazin_ (1788-1792) and the _Philosophisches Archiv_
  (1792-1795).

  See F. Nicolai, _Gedächtnisschrift auf J.A. Eberhard_ (Berlin and
  Stettin, 1810); also K.H. Jördens, _Lexicon deutscher Dichter und
  Prosaisten_.



EBERLIN, JOHANN ERNST (1702-1762), German musician and composer, was
born in Bavaria, and became afterwards organist in the cathedral at
Salzburg, where he died. Most of his compositions were for the church
(oratorios, &c.), but he also wrote some important fugues, sonatas and
preludes; and his pieces were at one time highly valued by Mozart.



EBERS, GEORG MORITZ (1837-1898), German Egyptologist and novelist, was
born in Berlin on the 1st of March 1837. At Göttingen he studied
jurisprudence, and at Berlin oriental languages and archaeology. Having
made a special study of Egyptology, he became in 1865 _docent_ in
Egyptian language and antiquities at Jena, and in 1870 he was appointed
professor in these subjects at Leipzig. He had made two scientific
journeys to Egypt, and his first work of importance, _Ägypten und die
Bücher Moses_, appeared in 1867-1868. In 1874 he edited the celebrated
medical papyrus ("Papyrus Ebers") which he had discovered in Thebes
(translation by H. Joachim, 1890). Ebers early conceived the idea of
popularizing Egyptian lore by means of historical romances. _Eine
ägyptische Königstochter_ was published in 1864, and obtained great
success. His subsequent works of the same kind--_Uarda_ (1877), _Homo
sum_ (1878), _Die Schwestern_ (1880), _Der Kaiser_ (1881), of which the
scene is laid in Egypt at the time of Hadrian, _Serapis_ (1885), _Die
Nilbraut_ (1887), and _Kleopatra_ (1894), were also well received, and
did much to make the public familiar with the discoveries of
Egyptologists. Ebers also turned his attention to other fields of
historical fiction--especially the 16th century (_Die Frau
Bürgermeisterin_, 1882; _Die Gred_, 1887)--without, however, attaining
the success of his Egyptian novels. Apart from their antiquarian and
historical interest, Ebers's books have not a very high literary value.
His other writings include a descriptive work on Egypt (_Ägypten in Wort
und Bild_, 2nd ed., 1880), a guide to Egypt (1886) and a life (1885) of
his old teacher, the Egyptologist Karl Richard Lepsius. The state of his
health led him in 1889 to retire from his chair at Leipzig on a pension.
He died at Tutzing in Bavaria, on the 7th of August 1898.

  Ebers's _Gesammelte Werke_ appeared in 25 vols. at Stuttgart
  (1893-1895). Many of his books have been translated into English. For
  his life see his _Die Geschichte meines Lebens_ (Stuttgart, 1893);
  also R. Gosche, _G. Ebers, der Forscher und Dichter_ (2nd ed.,
  Leipzig, 1887).



EBERSWALDE, a town of Germany, in the kingdom of Prussia, 28 m. N.E. of
Berlin by rail; on the Finow canal. Pop. (1905) 23,876. The town has a
Roman Catholic and two Evangelical churches, a school of forestry, a
gymnasium, a higher-grade girls' school and two schools of domestic
economy. It possesses a mineral spring, which attracts numerous summer
visitors, and has various industries, which include iron-founding and
the making of horse-shoe nails, roofing material and bricks. A
considerable trade is carried on in grain, wood and coals. In the
immediate neighbourhood are one of the chief brass-foundries in Germany
and an extensive government paper-mill, in which the paper for the notes
of the imperial bank is manufactured.

Eberswalde received its municipal charter in 1257. It was taken and
sacked during the Thirty Years' War. In 1747 Frederick the Great brought
a colony of Thuringian cutlers to the town, but this branch of industry
has entirely died out. About 4 m. to the north lies the old Cistercian
monastery of Chorin, the fine Gothic church of which contains the tombs
of several margraves of Brandenburg.



EBERT, FRIEDRICH ADOLF (1791-1834), German bibliographer, was born at
Taucha, near Leipzig, on the 9th of July 1791, the son of a Lutheran
pastor. At the age of fifteen he was appointed to a subordinate post in
the municipal library of Leipzig. He studied theology for a short time
at Leipzig, and afterwards philology at Wittenberg, where he graduated
doctor in philosophy in 1812. While still a student he had already
published, in 1811, a work on public libraries, and in 1812 another work
entitled _Hierarchiae in religionem ac literas commoda_. In 1813 he was
attached to the Leipzig University library, and in 1814 was appointed
secretary to the Royal library of Dresden. The same year he published
_F. Taubmanns Leben und Verdienste_, and in 1819 _Torquato Tasso_, a
translation from Pierre Louis Ginguené with annotations. The rich
resources open to him in the Dresden library enabled him to undertake
the work on which his reputation chiefly rests, the _Allgemeines
bibliographisches Lexikon_, the first volume of which appeared in 1821
and the second in 1830. This was the first work of the kind produced in
Germany, and the most scientific published anywhere. From 1823 to 1825
Ebert was librarian to the duke of Brunswick at Wolfenbüttel, but
returning to Dresden was made, in 1827, chief librarian of the Dresden
Royal library. Among his other works are--_Die Bildung des
Bibliothekars_ (1820), _Geschichte und Beschreibung der königlichen
öffentlichen Bibliothek in Dresden_ (1822), _Zur Handschriftenkunde_
(1825-1827), and _Culturperioden des obersächsischen Mittelalters_
(1825). Ebert was a contributor to various journals and took part in the
editing of Ersch and Gruber's great encyclopaedia. He died at Dresden on
the 13th of November 1834, in consequence of a fall from the ladder in
his library.

  See the article in _Ersch und Grubers Encyclopädie_, and that in the
  _Allg. deutsche Biog._ by his successor in the post of chief librarian
  in Dresden, Schnorr von Carolsfeld.



EBINGEN, a town of Germany, in the kingdom of Württemberg, on the
Schmiecha, a left-hand tributary of the Danube, 22 m. S. of Tübingen and
37 m. W. of Ulm by rail. It manufactures velvet and cotton-velvet
("Manchester") goods, stockings, stays, hats, needles, tools, &c. There
are also tanneries. Pop. 9000.



EBIONITES (Heb. [Hebrew: ebyonim], "poor men"), a name given to the
ultra-Jewish party in the early Christian church. It is first met with
in Irenaeus (_Adv. Haer._ i. 26. 2), who sheds no light on the origin of
the Ebionites, but says that while they admit the world to have been
made by the true God (in contrast to the Demiurge of the Gnostics), they
held Cerinthian views on the person of Christ, used only the Gospel of
Matthew (probably the Gospel according to the Hebrews--so Eusebius), and
rejected Paul as an apostate from the Mosaic Law, to the customs and
ordinances of which, including circumcision, they steadily adhered. A
similar account is given by Hippolytus (_Haer._ vii. 35), who invents a
founder named Ebion. Origen (_Contra Celsum_, v. 61; _In Matt._ tom.
xvi. 12) divides the Ebionites into two classes according to their
acceptance or rejection of the virgin birth of Jesus, but says that all
alike reject the Pauline epistles. This is confirmed by Eusebius, who
adds that even those who admitted the virgin birth did not accept the
pre-existence of Jesus as Logos and Sophia. They kept both the Jewish
Sabbath and the Christian Lord's day, and held extreme millenarian ideas
in which Jerusalem figured as the centre of the coming Messianic
kingdom. Epiphanius with his customary confusion makes two separate
sects, Ebionites and Nazarenes. Both names, however, refer to the same
people[1] (the Jewish Christians of Syria), the latter going back to the
designation of apostolic times (Acts xxiv. 5), and the former being the
term usually applied to them in the ecclesiastical literature of the 2nd
and 3rd centuries.

The origin of the Nazarenes or Ebionites as a distinct sect is very
obscure, but may be dated with much likelihood from the edict of Hadrian
which in 135 finally scattered the old church of Jerusalem. While
Christians of the type of Aristo of Pella and Hegesippus, on the
snapping of the old ties, were gradually assimilated to the great church
outside, the more conservative section became more and more isolated and
exclusive. "It may have been then that they called themselves the Poor
Men, probably as claiming to be the true representatives of those who
had been blessed in the Sermon on the Mount, but possibly adding to the
name other associations." Out of touch with the main stream of the
church they developed a new kind of pharisaism. Doctrinally they stood
not so much for a theology as for a refusal of theology, and, rejecting
the practical liberalism of Paul, became the natural heirs of those
early Judaizers who had caused the apostle so much annoyance and
trouble.

Though there is insufficient justification for dividing the Ebionites
into two separate and distinct communities, labelled respectively
Ebionites and Nazarenes, we have good evidence, not only that there were
grades of Christological thought among them, but that a considerable
section, at the end of the 2nd century and the beginning of the 3rd,
exchanged their simple Judaistic creed for a strange blend of Essenism
and Christianity. These are known as the Helxaites or Elchasaites, for
they accepted as a revelation the "book of Elchasai," and one Alcibiades
of Apamea undertook a mission to Rome about 220 to propagate its
teaching. It was claimed that Christ, as an angel 96 miles high,
accompanied by the Holy Spirit, as a female angel of the same stature,
had given the revelation to Elchasai in the 3rd year of Trajan (A.D.
100), but the book was probably quite new in Alcibiades' time. It taught
that Christ was an angel born of human parents, and had appeared both
before (e.g. in Adam and Moses) and after this birth in Judea. His
coming did not annul the Law, for he was merely a prophet and teacher;
Paul was wrong and circumcision still necessary. Baptism must be
repeated as a means of purification from sin, and proof against disease;
the sinner immerses himself "in the name of the mighty and most high
God," invoking the "seven witnesses" (sky, water, the holy spirits, the
angels of prayer, oil, salt and earth), and pledging himself to
amendment. Abstinence from flesh was also enjoined, and a good deal of
astrological fancy was interwoven with the doctrinal and practical
teaching. It is highly probable, too, that from these Essene Ebionites
there issued the fantastical and widely read "Clementine" literature
(_Homilies_ and _Recognitions_) of the 3rd century. Ebionite views
lingered especially in the country east of the Jordan until they were
absorbed by Islam in the 7th century.

  In addition to the literature cited see R.C. Ottley, _The Doctrine of
  the Incarnation_, part iii. § ii.; W. Moeller, _Hist. of the Christian
  Church_, i. 99; art. in Herzog-Hauck, _Realencyklopädie_, s.v.
  "Ebioniten"; also CLEMENTINE LITERATURE.


FOOTNOTE:

  [1] So A. Harnack, _Hist. of Dogma_, i. 301, and F.J.A. Hort,
    _Judaistic Christianity_, p. 199. Th. Zahn and J.B. Lightfoot ("St.
    Paul and the Three," in _Commentary on Galatians_) maintain the
    distinction.



EBNER-ESCHENBACH, MARIE, FREIFRAU VON (1830- ), Austrian novelist, was
born at Zdislavic in Moravia, on the 13th of September 1830, the daughter
of a Count Dubsky. She lost her mother in early infancy, but received a
careful intellectual training from two stepmothers. In 1848 she married
the Austrian captain, and subsequent field-marshal, Moritz von
Ebner-Eschenbach, and resided first at Vienna, then at Klosterbruck, where
her husband had a military charge, and after 1860 again at Vienna. The
marriage was childless, and the talented wife sought consolation in
literary work. In her endeavours she received assistance and encouragement
from Franz Grillparzer and Freiherr von Münch-Bellinghausen. Her first
essay was with the drama _Maria Stuart in Schottland_, which Philipp
Eduard Devrient produced at the Karlsruhe theatre in 1860. After some
other unsuccessful attempts in the field of drama, she found her true
sphere in narrative. Commencing with _Die Prinzessin von Banalien_ (1872),
she graphically depicts in _Bozena_ (Stuttgart, 1876, 4th ed. 1899) and
_Das Gemeindekind_ (Berlin, 1887, 4th ed. 1900) the surroundings of her
Moravian home, and in _Lotti, die Uhrmacherin_ (Berlin, 1883, 4th ed.
1900), _Zwei Comtessen_ (Berlin, 1885, 5th ed. 1898), _Unsühnbar_ (1890,
5th ed. 1900) and _Glaubenslos?_ (1893) the life of the Austrian
aristocracy in town and country. She also published _Neue Erzählungen_
(Berlin, 1881, 3rd ed. 1894), _Aphorismen_ (Berlin, 1880, 4th ed. 1895)
and _Parabeln, Märchen und Gedichte_ (2nd ed., Berlin, 1892). Frau von
Ebner-Eschenbach's elegance of style, her incisive wit and masterly
depiction of character give her a foremost place among the German
women-writers of her time. On the occasion of her seventieth birthday the
university of Vienna conferred upon her the degree of doctor of
philosophy, _honoris causa_.

  An edition of Marie von Ebner-Eschenbach's _Gesammelte Schriften_
  began to appear in 1893 (Berlin). See A. Bettelheim, _Marie von
  Ebner-Eschenbach: biographische Blätter_ (Berlin, 1900), and M.
  Necker, _Marie von Ebner-Eschenbach, nach ihren Werken geschildert_
  (Berlin, 1900).



EBOLI (anc. _Eburum_), a town of Campania, Italy, in the province of
Salerno, from which it is 16 m. E. by rail, situated 470 ft. above
sea-level, on the S. edge of the hills overlooking the valley of the
Sele. Pop. (1901) 9642 (town), 12,423 (commune). The sacristy of St
Francesco contains two 14th-century pictures, one by Roberto da Oderisio
of Naples. The ancient Eburum was a Lucanian city, mentioned only by
Pliny and in inscriptions, not far distant from the Campanian border. It
lay above the Via Popillia, which followed the line taken by the modern
railway. Some scanty remains of its ancient polygonal walls may still be
seen.     (T. As.)



EBONY (Gr. [Greek: ebenos]), the wood of various species of trees of the
genus _Diospyros_ (natural order Ebenaceae), widely distributed in the
tropical parts of the world. The best kinds are very heavy, are of a
deep black, and consist of heart-wood only. On account of its colour,
durability, hardness and susceptibility of polish, ebony is much used
for cabinet work and inlaying, and for the manufacture of
pianoforte-keys, knife-handles and turned articles. The best Indian and
Ceylon ebony is furnished by _D. Ebenum_, a native of southern India and
Ceylon, which grows in great abundance throughout the flat country west
of Trincomalee. The tree is distinguished from others by the inferior
width of its trunk, and its jet-black, charred-looking bark, beneath
which the wood is perfectly white until the heart is reached. The wood
is stated to excel that obtained from _D. reticulata_ of the Mauritius
and all other varieties of ebony in the fineness and intensity of its
dark colour. Although the centre of the tree alone is employed, reduced
logs 1 to 3 ft. in diameter can readily be procured. Much of the East
Indian ebony is yielded by the species _D. Melanoxylon_ (Coromandel
ebony), a large tree attaining a height of 60 to 80 ft., and 8 to 10 ft.
in circumference, with irregular rigid branches, and oblong or
oblong-lanceolate leaves. The bark of the tree is astringent, and mixed
with pepper is used in dysentery by the natives of India. The wood of
_D. tomentosa_, a native of north Bengal, is black, hard and of great
weight. _D. montana_, another Indian species, produces a yellowish-grey
soft but durable wood. _D. quaesita_ is the tree from which is obtained
the wood known in Ceylon by the name _Calamander_, derived by Pridham
from the Sinhalee _kalumindrie_, black-flowing. Its closeness of grain,
great hardness and fine hazel-brown colour, mottled and striped with
black, render it a valuable material for veneering and furniture making.
_D. Dendo_, a native of Angola, is a valuable timber tree, 25 to 35 ft.
high, with a trunk 1 to 2 ft. in diameter. The heart-wood is very black
and hard and is known as black ebony, also as billet-wood, and Gabun,
Lagos, Calabar or Niger ebony. What is termed Jamaica or West Indian
ebony, and also the green ebony of commerce, are produced by _Brya
Ebenus_, a leguminous tree or shrub, having a trunk rarely more than 4
in. in diameter, flexible spiny branches, and orange-yellow,
sweet-scented flowers. The heart-wood is rich dark brown in colour,
heavier than water, exceedingly hard and capable of receiving a high
polish.

From the book of Ezekiel (xxvii. 15) we learn that ebony was among the
articles of merchandise brought to Tyre; and Herodotus states (iii. 97)
that the Ethiopians every three years sent a tribute of 200 logs of it
to Persia. Ebony was known to Virgil as a product of India (_Georg._ ii.
116), and was displayed by Pompey the Great in his Mithradatic triumph
at Rome. By the ancients it was esteemed of equal value for durability
with the cypress and cedar (see Pliny, _Nat. Hist._ xii. 9, xvi. 79).
According to Solinus (_Polyhistor_, cap. lv. p. 353, Paris, 1621), it
was employed by the kings of India for sceptres and images, also, on
account of its supposed antagonism to poison, for drinking-cups. The
hardness and black colour of the wood appear to have given rise to the
tradition related by Pausanias, and alluded to by Southey in _Thalaba_,
i. 22, that the ebony tree produced neither leaves nor fruit, and was
never seen exposed to the sun.



EBRARD, JOHANNES HEINRICH AUGUST (1818-1888), German theologian, was
born at Erlangen on the 18th of January 1818. He was educated in his
native town and at Berlin, and after teaching in a private family became
_Privatdocent_ at Erlangen (1841) and then professor of theology at
Zürich (1844). In 1847 he was appointed professor of theology at
Erlangen, a chair which he resigned in 1861; in 1875 he became pastor of
the French reformed church in the same city. As a critic Ebrard occupied
a very moderate standpoint; as a writer his chief works were
_Christliche Dogmatik_ (2 vols., 1851), _Vorlesungen über praktische
Theologie_ (1864), _Apologetik_ (1874-1875, Eng. trans. 1886). He also
edited and completed H. Olshausen's commentary, himself writing the
volumes on the Epistle to the Hebrews, the Johannine Epistles, and
Revelation. In the department of belles-lettres he wrote a good deal
under such pseudonyms as Christian Deutsch, Gottfried Flammberg and
Sigmund Sturm. He died at Erlangen on the 23rd of July 1888.



EBRO (anc. _Iberus_ or _Hiberus_), the only one of the five great rivers
of the Iberian Peninsula (Tagus, Douro, Ebro, Guadalquivir, Guadiana)
which flows into the Mediterranean. The Ebro rises at Fuentibre, a
hamlet among the Cantabrian Mountains, in the province of Santander; at
Reinosa, 4 m. east, it is joined on the right by the Hijar, and thus
gains considerably in volume. It flows generally east by south through a
tortuous valley as far as Miranda de Ebro, passing through the
celebrated Roman bridge known as La Horadada ("the perforated"), near
Oña in Burgos. From Miranda it winds south-eastward through the wide
basin enclosed on the right by the highlands of Old Castile and western
Aragon, and on the left by the Pyrenees. The chief cities on its banks
are Logroño, Calahorra, Tudela, Saragossa and Caspe. Near Mora in
Catalonia it forces a way through the coastal mountains, and, passing
Tortosa, falls into the Mediterranean about 80 m. south-west of
Barcelona, after forming by its delta a conspicuous projection on the
otherwise regular coast line. In its length, approximately 465 m., the
Ebro is inferior to the Tagus, Guadiana and Douro; it drains an area of
nearly 32,000 sq. m. Its principal tributaries are--from the right hand
the Jalon with its affluent the Jiloca, the Huerva, Aguas, Martin,
Guadalope and Matarraña; from the left the Ega, Aragon, Arba, Gallego,
and the Segre with its intricate system of confluent rivers. The Ebro
and its tributaries have been utilized for irrigation since the Moorish
conquest; the main stream becomes navigable by small boats about Tudela;
but its value as a means of communication is almost neutralized by the
obstacles in its channel, and seafaring vessels cannot proceed farther
up than Tortosa. The great Imperial Canal, begun under the emperor
Charles V. (1500-1558), proceeds along the right bank of the river from
a point about 3 m. below Tudela, to El Burgo de Ebro, 5 m. below
Saragossa; the irrigation canal of Tauste skirts the opposite bank for a
shorter distance; and the San Carlos or New Canal affords direct
communication between Amposta at the head of the delta and the harbour
of Los Alfaques. From Miranda to Mora the Bilbao-Tarragona railway
follows the course of the Ebro along the right bank.



EBROÏN (d. 681), Frankish "mayor of the palace," was a Neustrian, and
wished to impose the authority of Neustria over Burgundy and Austrasia.
In 656, at the moment of his accession to power, Sigebert III., the king
of Austrasia, had just died, and the Austrasian mayor of the palace,
Grimoald, was attempting to usurp the authority. The great nobles,
however, appealed to the king of Neustria, Clovis II., and unity was
re-established. But in spite of a very firm policy Ebroïn was unable to
maintain this unity, and while Clotaire III., son of Clovis II., reigned
in Neustria and Burgundy, he was obliged in 660 to give the Austrasians
a special king, Childeric II., brother of Clotaire III., and a special
mayor of the palace, Wulfoald. He endeavoured to maintain at any rate
the union of Neustria and Burgundy, but the great Burgundian nobles
wished to remain independent, and rose under St Leger (Leodegar), bishop
of Autun, defeated Ebroïn, and interned him in the monastery of Luxeuil
(670). A proclamation was then issued to the effect that each kingdom
should keep its own laws and customs, that there should be no further
interchange of functionaries between the kingdoms, and that no one
should again set up a tyranny like that of Ebroïn. Soon, however, Leger
was defeated by Wulfoald and the Austrasians, and was himself confined
at Luxeuil in 673. In the same year, taking advantage of the general
anarchy, Ebroïn and Leger left the cloister and soon found themselves
once more face to face. Each looked for support to a different
Merovingian king, Ebroïn even proclaiming a false Merovingian as
sovereign. In this struggle Leger was vanquished; he was besieged in
Autun, was forced to surrender and had his eyes put out, and, on the
12th of October 678, he was put to death after undergoing prolonged
tortures. The church honours him as a saint. After his death Ebroïn
became sole and absolute ruler of the Franks, imposing his authority
over Burgundy and subduing the Austrasians, whom he defeated in 678 at
Bois-du-Fay, near Laon. His triumph, however, was short-lived; he was
assassinated in 681, the victim of a combined attack of his numerous
enemies. He was a man of great energy, but all his actions seem to have
been dictated by no higher motives than ambition and lust of power.

  See _Liber historiae Francorum_, edited by B. Krusch, in _Mon. Germ.
  hist. script. rer. Merov._ vol. ii.; _Vita sancti Leodegarii_, by
  Ursinus, a monk of St Maixent (Migne, _Patr. Latina_, vol. xcvi.);
  "Vita metrica" in _Poetae Latini aevi Carolini_, vol. iii. (_Mon.
  Germ. hist._); J.B. Pitra, _Histoire de Saint Léger_ (Paris, 1846);
  and J. Friedrich, "Zur Gesch. des Hausmeiers Ebroïn," in the
  _Proceedings of the Academy of Munich_ (1887, pp. 42-61).
       (C. Pf.)



EBURACUM, or EBORACUM (probably a later variant), the Roman name of York
(q.v.) in England. Established about A.D. 75-80 as fortress of the
Ninth legion and garrisoned (after the annihilation of that legion about
A.D. 118) by the Sixth legion, it developed outside its walls a town of
civil life, which later obtained Roman municipal rank and in the 4th
century was the seat of a Christian bishop. The fortress and town were
separated by the Ouse. On the left bank, where the minster stands, was
the fortress, of which the walls can still be partly traced, and one
corner (the so-called Multangular Tower) survives. The municipality
occupied the right bank near the present railway station. The place was
important for its garrison and as an administrative centre, and the town
itself was prosperous, though probably never very large. The name is
preserved in the abbreviated form Ebor in the official name of the
archbishop of York, but the philological connexion between Eboracum and
the modern name York is doubtful and has probably been complicated by
Danish influence.     (F. J. H.)



EÇA DE QUEIROZ, JOSÉ MARIA (1843-1900), Portuguese writer, was born at
the northern fishing town of Povoa de Varzim, his father being a retired
judge. He went through the university of Coimbra, and on taking his
degree in law was appointed Administrador de Concelho at Leiria, but
soon tired of the narrow mental atmosphere of the old cathedral town and
left it. He accompanied the Conde de Rezende to Egypt, where he assisted
at the opening of the Suez Canal, and to Palestine, and on his return
settled down to journalism in Lisbon and began to evolve a style, at
once magical and unique, which was to renovate his country's prose.
Though he spent much of his days with the philosopher sonneteer Anthero
de Quental, and the critic Jayme Batalha Reis, afterwards consul-general
in London, he did not restrict his intimacy to men of letters, but
frequented all kinds of society, acquiring a complete acquaintance with
contemporary Portuguese life and manners. Entering the consular service
in 1872, he went to Havana, and, after a tour in the United States, was
transferred two years later to Newcastle-on-Tyne and in 1876 to Bristol.
In 1888 he became Portuguese consul-general in Paris, and there died in
1900.

Queiroz made his literary début in 1870 by a sensational story, _The
Mystery of the Cintra Road_, written in collaboration with the art
critic Ramalho Ortigão, but the first publication which brought him fame
was _The Farpas_, a series of satirical and humorous sketches of various
phases of social life, which, to quote the poet Guerra Junqueiro,
contain "the epilepsy of talent." These essays, the joint production of
the same partners, criticized and ridiculed the faults and foibles of
every class in turn, mainly by a comparison with the French, for the
education of Queiroz had made him a Frenchman in ideas and sympathies.
His Brazilian friend, Eduardo Prado, bears witness that at this period
French literature, especially Hugo's verse, and even French politics,
interested Queiroz profoundly, while he altogether ignored the
_belles-lettres_ of his own country and its public affairs. This phase
lasted for some years, and even when he travelled in the East he was
inclined to see it with the eyes of Flaubert, though the publication of
_The Relic_ and that delightful prose poem _Sweet Miracle_ afterwards
showed that he had been directly impressed and deeply penetrated by its
scenery, poetry and mysticism. The Franco-German War of 1870, however,
by lowering the prestige of France, proved the herald of a national
Portuguese revival, and had a great influence on Queiroz, as also had
his friend Oliveira Martins (q.v.), the biographer of the patriot kings
of the Aviz dynasty. He founded the Portuguese Realist-Naturalist
school, of which he remained for the rest of his life the chief
exponent, by a powerful romance, _The Crime of Father Amaro_, written in
1871 at Leiria but only issued in 1875. Its appearance then led to a
baseless charge that he had plagiarized _La Faute de l'Abbé Mouret_, and
ill-informed critics began to name Queiroz the Portuguese Zola, though
he clearly occupied an altogether different plane in the domain of art.
During his stay in England he produced two masterpieces, _Cousin Basil_
and _The Maias_, but they show no traces of English influence, nor again
are they French in tone, for, living near to France, his disillusionment
progressed and was completed when he went to Paris and had to live under
the régime of the Third Republic. Settling at Neuilly, the novelist
became chronicler, critic, and letter-writer as well, and in all these
capacities Queiroz displayed a spontaneity, power and artistic finish
unequalled in the literature of his country since the death of Garrett.
A bold draughtsman, he excelled in freshness of imagination and careful
choice and collocation of words, while his warmth of colouring and
brilliance of language speak of the south. Many of his pages descriptive
of natural scenery, such for instance as the episode of the return to
Tormes in _The City and the Mountains_, have taken rank as classic
examples of Portuguese prose, while as a creator of characters he stood
unsurpassed by any writer of his generation in the same field. He
particularly loved to draw and judge the middle class, and he mocks at
and chastises its hypocrisy and narrowness, its veneer of religion and
culture, its triumphant lying, its self-satisfied propriety, its cruel
egotism. But though he manifested a predilection for middle-class types,
his portrait gallery comprises men and women of all social conditions.
_The Maias_, his longest book, treats of _fidalgos_, while perhaps his
most remarkable character study is of a servant, Juliana, in _Cousin
Basil_. At least two of his books, this latter and _The Crime of Father
Amaro_, are _chroniques scandaleuses_ in their plots and episodes; these
volumes, however, mark not only the high-water line of the
Realist-Naturalist school in Portugal, but are in themselves, leaving
aside all accidentals, creative achievements of a high order.

Though Queiroz was a keen satirist of the ills of society, his pages
show hardly a trace of pessimism. _The City and the Mountains_, and in
part _The Relic_ also, reveal the apostle of Realism as an idealist and
dreamer, a true representative of that Celtic tradition which survives
in the race and has permeated the whole literature of Portugal. _The
Mandarin_, a fantastic variation on the old theme of a man self-sold to
Satan, and _The Illustrious House of Ramires_, are the only other
writings of his that require mention, except _The Correspondence of
Fradique Mendes_. In conjunction with Anthero de Quental and Jayme
Batalha Reis, Queiroz invented under that name a smart man of the world
who had something of himself and something of Eduardo Prado, and made
him correspond on all sorts of subjects with imaginary friends and
relatives to the delight of the public, many of whom saw in him a
mysterious new writer whose identity they were eager to discover. These
sparkling and humorous letters are an especial favourite with admirers
of Queiroz, because they reveal so much of his very attractive
personality, and perhaps the cleverest of the number, that on Pacheco,
has received an English dress. In addition to his longer and more
important works, Queiroz wrote a number of short stories, some of which
have been printed in a volume under the title of _Contos_. The gems of
this remarkable collection are perhaps _The Peculiarities of a
Fair-haired Girl_, _A Lyric Poet_, _José Matthias_, _The Corpse_, and
_Sweet Miracle_.

  Most of his books have gone through many editions, and they are even
  more appreciated in the Brazils than in Portugal. It should be
  mentioned that the fourth edition of _Father Amaro_ is entirely
  different in form and action from the first, the whole story having
  been rewritten. One of Queiroz's romances and two of his short stories
  have been published in English. An unsatisfactory version of _Cousin
  Basil_, under the title _Dragon's Teeth_, appeared at Boston, U.S.A.,
  in 1889, while _Sweet Miracle_ has had three editions in England and
  one in America, and there is also a translation of _O Defunto_ (_The
  Corpse_) under the name of _Our Lady of the Pillar_.

  An admirable critical study of the work of Queiroz will be found in _A
  Geração Nova--Os Novellistas_, by J. Pereira de Sampaio (_Bruno_),
  (Oporto, 1886). The _Revista moderna_ of the 20th of November 1897 was
  entirely devoted to him. Senhor Batalha Reis gives interesting
  reminiscences of the novelist's early days in his preface to some
  prose fragments edited by him and named _Prosas Barbaras_ (Oporto,
  1903).     (E. Pr.)



ÉCARTÉ (Fr. for "separated," "discarded"), a game at cards, of modern
origin, probably first played in the Paris _salons_ in the first quarter
of the 19th century. It is a development of a very old card game called
_la triomphe_ or _French-ruff_. Écarté is generally played by two
persons, but a pool of three may be formed, the player who is out taking
the place of the loser, and the winner of two consecutive games winning
the pool. At French écarté (but not at English) bystanders who are
betting may advise the players, but only by pointing to the cards they
desire them to play, and the loser of the game goes out, one of the
_rentrants_ taking his place, unless the loser is playing _la chouette_,
i.e. playing single-handed against two, and taking all bets.

The small cards (from the two to the six, both inclusive) are removed
from an ordinary pack. The players cut for deal, the highest having the
choice. The king is the highest card, the ace ranking after the knave.
The dealer gives five cards to his adversary, and five to himself, by
two at a time to each and by three at a time to each, or vice versa. The
eleventh card is turned up for trumps. If it is a king, the dealer
scores one, at any time before the next deal. The non-dealer then looks
at his cards. If satisfied with them he plays, and there is no
discarding; if not satisfied he "proposes." The dealer may either accept
or refuse. If he accepts, each player discards face downwards as many
cards as he thinks fit, and fresh ones are given from the undealt cards
or "stock," first to complete the non-dealer's hand to five, then to
complete the dealer's. To ask for "a book" is to ask for five cards.
Similarly a second proposal may be made, and so on, until one player is
satisfied with his hand. If the dealer refuses, the hand is played
without discarding. If the non-dealer announces that he holds the king
of trumps, he scores one; and similarly, if the dealer holds the king
and announces it, he scores one. The announcement must be made before
playing one's first card, or if that card be the king, on playing it.
The non-dealer, being satisfied with his hand, leads a card. The dealer
plays a card to it, the two cards thus played forming a trick. The
winner of the trick leads to the next, and so on. The second to play to
a trick must follow suit if able, and must win the trick if he can.

The scores are for the king and for the majority of tricks. The player
who wins three tricks scores one for the "point"; if he wins all five
tricks, he scores two for the "vole." If the non-dealer plays without
proposing, or the dealer refuses the first proposal, and fails to win
three tricks, the adversary scores two, but no more even if he wins the
vole. The game is five up. The points are conveniently marked with a
three-card and a two-card, as at euchre. The three is put face upwards
with the two face downwards on the top of it. When one or two or three
points are scored the top card is moved so as to expose them. At four,
one pip of the two-card is put under the other card. Games may be
recorded similarly.

  _Hints to Players._--The following hints may be of service to
  beginners:--

  Shuffle thoroughly after every deal.

  Do not announce the king until in the act of playing your first card.

  The hands which should be played without proposing, called _jeux de
  règle_ (standard hands), ought to be thoroughly known. They are as
  follows:--

  1. All hands with three or more trumps, whatever the other cards.

  2. Hands with _two trumps_ which contain also--

    (a) Any three cards of one plain suit;

    (b) Two cards of one plain suit, one being as high as a queen;

    (c) Two small cards of one suit, the fifth card being a king of
    another suit;

    (d) Three high cards of different suits.

  3. Hands with _one trump_, which contain also--

    (a) King, queen, knave of one suit, and a small card of another;

    (b) Four cards of one suit headed by king;

    (c) Three cards of one suit headed by queen, and queen of another
    suit.

  4. Hands with _no trump_, which contain three queens or cards of equal
  value in different suits, e.g., four court cards.

  5. Hands from which only two cards can be discarded without throwing a
  king or a trump.

  Holding cards which make the point certain, propose. If you hold a
  _jeu de règle_, and one of the trumps is the king, propose, as your
  adversary cannot then take in the king.

  When discarding, throw out all cards except trumps and kings.

  If your adversary proposes you should accept, unless you are guarded
  in three suits (a queen being a sufficient guard), or in two suits
  with a trump, or in one suit with two trumps. Hence the rule not to
  discard two cards, unless holding the king of trumps, applies to the
  dealer.

  The hands with which to refuse are the same as those with which to
  play without proposing, except as follows:--

  1. Two trumps and three cards of one plain suit should not be played
  unless the plain suit is headed by a court card.

  2. One trump and a tierce major is too weak, unless the fifth card is
  a court card. With similar hands weaker in the tierce major suit,
  accept unless the fifth card is a queen.

  3. One trump and four cards of a plain suit is too weak to play.

  4. One trump and two queens is too weak, unless both queens are singly
  guarded.

  5. One trump, queen of one suit, and knave guarded of another should
  not be played unless the queen is also guarded, or the card of the
  fourth suit is a court card.

  6. One trump, a king and a queen, both unguarded, should not be
  played, unless the fourth suit contains a card as high as an ace.

  7. Four court cards without a trump are too weak to play, unless they
  are of three different suits.

  Refuse with three queens, if two are singly guarded; otherwise,
  accept.

  Lead from your guarded suit, and lead the highest.

  If the strong suit led is not trumped, persevere with it, unless with
  king of trumps, or queen (king not having been announced), or knave
  ace, when lead a trump before continuing your suit.

  You should not lead trumps at starting, unless you hold king or queen,
  knave, or knave ace, with court cards out of trumps.

  The score has to be considered. If the dealer is at four, and the king
  is not in your hand nor turned up, play any cards without proposing
  which give an even chance of three tricks, e.g. a queen, a guarded
  knave, and a guarded ten. The same rule applies to the dealer's
  refusal.

  At the adverse score of four, and king not being in hand or turned up,
  any hand with one trump should be played, unless the plain cards are
  very small and of different suits.

  If the non-dealer plays without proposing when he is four to three,
  and the dealer holds the king he ought not to mark it. The same rule
  applies to the non-dealer after a refusal, if the dealer is four to
  three.

  At the score of non-dealer three, dealer four, the dealer should
  refuse on moderate cards, as the player proposing at this score must
  have a very bad hand.

  At four a forward game should not be played in trumps, as there is no
  advantage in winning the vole.

  _Laws of Écarté._--The following laws are abridged from the revised
  code adopted by the Turf Club:--A cut must consist of at least two
  cards. Card exposed in cutting, fresh cut. Order of distribution of
  cards, whether by three and two, or vice versa, once selected, dealer
  must not change it during game. Player announcing king when he has not
  got it, and playing a card without declaring error, adversary may
  correct score and have hand played over again. If offender wins point
  or vole that hand, he scores one less than he wins. Proposal,
  acceptance, or refusal made cannot be retracted. Cards discarded must
  not be looked at. Cards exposed in giving cards to non-dealer, he has
  option of taking them or of having next cards; dealer exposing his own
  cards, no penalty. Dealer turning up top card after giving cards,
  cannot refuse second discard. Dealer accepting when too few cards in
  stock to supply both, non-dealer may take cards, and dealer must play
  his hand. Card led in turn cannot be taken up again. Card played to a
  lead can only be taken up prior to another lead, to save revoke or to
  correct error of not winning trick. Card led out of turn may be taken
  up prior to its being played to. Player naming one suit and leading
  another, adversary has option of requiring suit named to be led. If
  offender has none, no penalty. Player abandoning hand, adversary is
  deemed to win remaining tricks, and scores accordingly. If a player
  revokes or does not win trick when he can do so, the adversary may
  correct score and have hand replayed.

  See _Académie des jeux_ (various editions after the first quarter of
  the 19th century); Hoyle's _Games_ (various editions about the same
  dates); Ch. Van-Tenac et Louis Delanoue, _Traité du jeu de l'écarté_
  (Paris, 1845; translated in Bohn's _Handbook of Games_, London, 1850);
  "Cavendish," _The Laws of Écarté, adopted by the Turf Club, with a
  Treatise on the Game_ (London, 1878); _Pocket Guide to Écarté_
  ("Cavendish," 1897); Foster's _Encyclopaedia of Indoor Games_ (1903).



ECBATANA (_Agbatana_ in Aeschylus, _Hangmatana_ in Old Persian, written
_Agamtanu_ by Nabonidos, and _Agamatanu_ at Behistun, mod. _Hamadan_),
the capital of Astyages (Istuvegu), which was taken by Cyrus in the
sixth year of Nabonidos (549 B.C.). The Greeks supposed it to be the
capital of Media, confusing the Manda, of whom Astyages was king, with
the Mada or Medes of Media Atropatene, and ascribed its foundation to
Deioces (the _Daiukku_ of the cuneiform inscriptions), who is said to
have surrounded his palace in it with seven concentric walls of
different colours. Under the Persian kings, Ecbatana, situated at the
foot of Mount Elvend, became a summer residence; and was afterwards the
capital of the Parthian kings. Sir H. Rawlinson attempted to prove that
there was a second and older Ecbatana in Media Atropatene, on the site
of the modern Takht-i-Suleiman, midway between Hamadan and Tabriz
(_J.R.G.S._ x. 1841), but the cuneiform texts imply that there was only
one city of the name, and Takht-i-Suleiman is the Gazaca of classical
geography. The Ecbatana at which Cambyses is said by Herodotus (iii. 64)
to have died is probably a blunder for Hamath.

  See Perrot and Chipiez, _History of Art in Persia_ (Eng. trans.,
  1892); M. Dieulafoy, _L'Art antique de la Perse_, pt. i. (1884); J. de
  Morgan, _Mission scientifique en Perse_, ii. (1894). See HAMADAN and
  PERSIA: _Ancient History_, § v. 2.     (A. H. S.)



ECCARD, JOHANN (1553-1611), German composer of church music, was born at
Mühlhausen on the Unstrut, Prussia, in 1553. At the age of eighteen he
went to Munich, where he became the pupil of Orlando Lasso. In his
company Eccard is said to have visited Paris, but in 1574 we find him
again at Mühlhausen, where he resided for four years, and edited,
together with Johann von Burgk, his first master, a collection of sacred
songs, called _Crepundia sacra Helmboldi_ (1577). Soon afterwards he
obtained an appointment as musician in the house of Jacob Fugger, the
Augsburg banker. In 1583 he became assistant conductor, and in 1599
conductor, at Königsberg, to Georg Friedrich, margrave of
Brandenburg-Anspach, the administrator of Prussia. In 1608 he was called
by the elector Joachim Friedrich to Berlin as chief conductor, but this
post he held only for three years, owing to his premature death at
Königsberg in 1611. Eccard's works consist exclusively of vocal
compositions, such as songs, sacred cantatas and chorales for four or
five, and sometimes for seven, eight, or even nine voices. Their
polyphonic structure is a marvel of art, and still excites the
admiration of musicians. At the same time his works are instinct with a
spirit of true religious feeling. His setting of the beautiful words
"Ein' feste Burg ist unser Gott" is still regarded by the Germans as
their representative national hymn. Eccard and his school are
inseparably connected with the history of the Reformation.

  Of Eccard's songs a great many collections are extant; see K.G.A. von
  Winterfeld, _Der Evangelische Kirchengesang_ (1843); Döring
  (_Choralkunde_, p. 47).



ECCELINO [or EZZELINO] DA ROMANO (1194-1259), Ghibelline leader, and
supporter of the emperor Frederick II., was born on the 25th of April
1194. He belonged to a family descended from a German knight named
Eccelin, who followed the emperor Conrad II. to Italy about 1036, and
received the fief of Romano near Padua. Eccelin's grandson was Eccelino
III., surnamed the Monk, who divided his lands between his two sons in
1223, and died in 1235. The elder of these two sons was Eccelino, who in
early life began to take part in family and other feuds, and in 1226, at
the head of a band of Ghibellines, seized Verona and became _podestà_ of
the city. He soon lost Verona, but regained it in 1230; and about this
time came into relations with Frederick II., who in 1232 issued a
charter confirming him in his possessions. In 1236 when besieged in
Verona he was saved by the advance of the emperor, who in November of
the same year took Vicenza and entrusted its government to Eccelino. In
1237 he obtained authority over Padua and Treviso; and on the 27th of
November in that year he shared in the victory gained by the emperor
over the Lombards at Cortenuova. In 1238 he married Frederick's natural
daughter, Selvaggia; in 1239 was appointed imperial vicar of the march
of Treviso; but in the same year was excommunicated by Pope Gregory IX.
He was constantly engaged in increasing his possessions; was present at
the siege of Parma in 1247, and after Frederick's death in 1250 he
supported his son, the German king Conrad IV. His cruelties had,
however, aroused general disgust, and in 1254 he was again
excommunicated. In 1256 Pope Alexander IV. proclaimed a crusade against
him, and a powerful league was soon formed under the leadership of
Philip, archbishop of Ravenna. Padua was taken from Eccelino, but on the
1st of September 1258 he defeated his enemies at Torricella. He then
made an attempt on Milan, and the rival forces met at Cassano on the
27th of September 1259, when Eccelino was wounded and taken prisoner.
Enraged at his capture, he tore the bandages from his wounds, refused to
take nourishment, and died at Soncino on the 7th of October 1259. In the
following year his brother Albert was put to death, and the Romano
family became extinct. Eccelino, who is sometimes called the _tyrant_,
acquired a terrible reputation on account of his cruelties, a reputation
that won for him the immortality of inclusion in Dante's _Inferno_; but
his unswerving loyalty to Frederick II. forms a marked contrast to the
attitude of many of his contemporaries.

Eccelino is the subject of a novel by Cesare Cantu and of a drama by J.
Eichendorff.

  See J.M. Gittermann, _Ezzelino da Romano_ (Freiburg, 1890); S. Mitis,
  _Storia d' Ezzelino IV. da Romano_ (Maddaloni, 1896); and F. Stieve,
  _Ezzelino von Romano_ (Leipzig, 1909).



ECCENTRIC (from Gr. [Greek: ek], out of, and [Greek: kentron], centre),
literally "out from the centre," and thus used to connote generally any
deviation from the normal. In astronomy the word denotes a circle round
which a body revolves, but whose centre is displaced from the visible
centre of motion. In the ancient astronomy the ellipses in which it is
now known that the planets revolve around the sun could not be
distinguished from circles, but the unequal angular motion due to
ellipticity was observed. The theory of the eccentric was that the
centre of the epicycle of each planet moved uniformly in a circle, the
centre of which was displaced from that of the earth by an amount double
the eccentricity of the actual ellipse, as the case is now understood.
When measured around this imaginary centre, which is so situated on the
major axis of the ellipse that the focus, or place of the real sun, is
midway between it and the centre of the ellipse, the motion is
approximately uniform. In engineering, an eccentric is a mechanical
device for converting rotary into reciprocating motion (see
STEAM-ENGINE). For eccentric angle see ELLIPSE.



ECCHELLENSIS (or ECHELLENSIS), ABRAHAM (d. 1664), a learned Maronite,
whose surname is derived from Eckel in Syria, where he was born towards
the close of the 16th century. He was educated at the Maronite college
in Rome, and, after taking his doctor's degree in theology and
philosophy, returned for a time to his native land. He then became
professor of Arabic and Syriac in the college of the Propaganda at Rome.
Called to Paris in 1640 to assist Le Jay in the preparation of his
polyglot Bible, he contributed to that work the Arabic and Latin
versions of the book of Ruth and the Arabic version of the third book of
Maccabees. In 1646 he was appointed professor of Syriac and Arabic at
the Collège de France. Being invited by the Congregation of the
Propaganda to take part in the preparation of an Arabic version of the
Bible, Ecchellensis went again in 1652 or 1653 to Rome. He published
several Latin translations of Arabic works, of which the most important
was the _Chronicon Orientale_ of Ibnar-Rahib (Paris, 1653), a history of
the patriarchs of Alexandria. He was engaged in an interesting
controversy with John Selden as to the historical grounds of episcopacy,
in the course of which he published his _Eutychius vindicatus, sive
Responsio ad Seldeni Origines_ (Rome, 1661). Conjointly with Giovanni
Borelli he wrote a Latin translation of the 5th, 6th and 7th books of
the _Conics_ of Apollonius of Perga (1661). He died at Rome in 1664.



ECCLES, a municipal borough in the Eccles parliamentary division of
Lancashire, England, 4 m. W. of Manchester, of which it forms
practically a suburb. Pop. (1901) 34,369. It is served by the London &
North-Western railway and by the Birkenhead railway (North-Western and
Great Western joint). The Manchester Ship Canal passes through. The
church of St Mary is believed to date from the 12th century, but has
been enlarged and wholly restored in modern times. There are several
handsome modern churches and chapels, a town hall, and numerous cotton
mills, while silk-throwing and the manufacture of fustians and ginghams
are also among the industries, and there are also large engine works. A
peculiar form of cake is made here, taking name from the town, and has a
wide reputation. Eccles was incorporated in 1892, and the corporation
consists of a mayor, 6 aldermen and 18 councillors. The borough
maintains the tramway service, &c., but water and gas are supplied from
Manchester and Salford respectively. Area, 2057 acres.

Before the Reformation the monks of Whalley Abbey had a grange here at
what is still called Monks' Hall; and in 1864 many thousands of silver
pennies of Henry III. and John of England and William I. of Scotland
were discovered near the spot. Robert Ainsworth, the author of the Latin
and English dictionary so long familiar to English students, was born at
Eccles in 1660; and it was at the vicarage that William Huskisson
expired on the 15th of September 1830 from injuries received at the
opening of the Liverpool & Manchester railway. From early times "wakes"
were held at Eccles, and bull-baiting, bear-baiting and cock-fighting
were carried on. Under Elizabeth these festivals, which had become
notoriously disorderly, were abolished, but were revived under James I.,
and maintained until late in the 19th century on public ground. The
cockpit remained on the site of the present town hall. A celebration on
private property still recalls these wakes.



ECCLESFIELD, a township in the Hallamshire parliamentary division of the
West Riding of Yorkshire, England, 5 m. N. of Sheffield, on the Great
Central and Midland railways. The church of St Mary is Perpendicular,
with a central tower, and contains excellent woodwork. It formerly bore,
and must have deserved, the familiar title of the "Minster of the
Moors." Ecclesfield was the seat of a Benedictine priory, which passed
to the Carthusians in the 14th century. Cutlery and tools are largely
manufactured, and there are coal-mines, paper mills and iron and
fire-clay works. After the inclusion within the county borough of
Sheffield of part of the civil parish of Ecclesfield in 1901, the
population was 18,324.



ECCLESHALL, a market town in the north-western parliamentary division of
Staffordshire, England; 7 m. N.W. from Stafford, and 4 W. of Norton
Bridge station on the London & North-Western main line. Pop. (1901)
3799. The church of the Holy Trinity, one of the most noteworthy in
Staffordshire, is principally Early English, and has fine stained glass.
Several bishops of Lichfield are buried here, as Eccleshall Castle was
the episcopal residence from the 13th century until 1867. Of this the
ancient remains include a picturesque tower and bridge. To the west on
the borders of Shropshire is Blore Heath, the scene of a defeat of the
Lancastrians by the Yorkists in 1459.



ECCLESIA (Gr. [Greek: ekklêsia], from [Greek: ek], out, and [Greek:
kalein], to call), in ancient Athens, the general assembly of all the
freemen of the state. In the primitive unorganized state the king was
theoretically absolute, though his great nobles meeting in the Council
(see BOULE) were no doubt able to influence him considerably. There is,
however, no doubt that in the earliest times the free people, i.e. the
fighting force of the state, were called together to ratify the
decisions of the king, and that they were gradually able to enforce
their wishes against those of the nobles. In Athens, as in Rome, where
the Plebs succeeded in their demand for the codification of the laws
(the Twelve Tables), it was no doubt owing to the growing power of the
people meeting in the Agora that Draco was entrusted with the task of
publishing a code of law and so putting an end to the arbitrary
judicature of the aristocratic party. But there is no evidence that the
Ecclesia had more than a _de facto_ existence before Solon's reforms.

The precise powers which Solon gave the people are not known. It is
clear that the executive power in the state (see ARCHON) was still
vested in the Eupatrid class. It is obvious, therefore, that a moderate
reformer would endeavour to give to the people some control over the
magistracy. Now in speaking of the Thetes (the lowest of the four
Solonian classes; see SOLON), Aristotle's _Constitution of Athens_ says
that Solon gave them merely "a share in the Ecclesia and the Law
Courts," and in the _Politics_ we find that he gave them the right of
electing the magistrates and receiving their accounts at the end of the
official year. Thus it seems that the "mixed" character of Solon's
constitution consisted in the fact that though the officials of the
state were still necessarily Eupatrid, the Ecclesia elected those of the
Eupatrids whom they could trust, and further had the right of
criticizing their official actions. Secondly, all our accounts agree
that Solon admitted the Thetes to the Ecclesia, thus recognizing them as
citizens. Under Cleisthenes the Ecclesia remained the sovereign power,
but the Council seems to have become to some extent a separate
administrative body. The relation of Boule and Ecclesia in the
Cleisthenic democracy was of the greatest importance. The Ecclesia
alone, a heterogeneous body of untrained citizens, could not have
passed, nor even have drawn up intelligible measures; all the
preliminary drafting was done by the small committee of the Boule which
was in session at any particular time. In the 5th century the functions
of the Ecclesia and the popular courts of justice were vastly increased
by the exigencies of empire. At the beginning of the 4th century B.C.
the system of payment was introduced (see below). In 308 B.C. Demetrius
of Phalerum curtailed the power of the Ecclesia by the institution of
the _Nomophylaces_ (Guardians of the Law), who prevented the Ecclesia
from voting on an illegal or injurious motion. Under Roman rule the
powers of the Ecclesia and the popular courts were much diminished, and
after 48 B.C. (the franchise being frequently sold to any casual alien)
the Demos (people) was of no importance. They still assembled to pass
psephisms in the theatre and to elect strategi, and, under Hadrian, had
some small judicial duties, but as a governing body the Ecclesia died
when Athens became a _civitas libera_ under Roman protection.

_Constitution and Functions._--Throughout the period of Athenian
greatness the Ecclesia was the sovereign power, not only in practice but
also in theory. The assembly met in early times near the sanctuary of
Aphrodite Pandemus (i.e. south of the Acropolis), but, in the 5th and
4th centuries, the regular place of meeting was the Pnyx. From the 5th
century it met sometimes in the theatre, which in the 3rd century was
the regular place. From Demosthenes we learn that in his time special
meetings were held at Peiraeus, and, in the last centuries B.C.,
meetings were held at Athens and Peiraeus alternately. Certain meetings,
however, for voting ostracism (q.v.) and on questions affecting
individual status took place in the Agora. Meetings were (1) ordinary,
(2) extraordinary, and (3) convened by special messengers ([Greek:
kyriai], [Greek: synklêtoi] and [Greek: kataklêtoi]), these last being
called when it was desirable that the country people should attend. At
ordinary meetings the attendance was practically confined to Athenian
residents. According to Aristotle there were four regular meetings in
each prytany (see BOULE); probably only the first of these was called
[Greek: kyria]. It is certain, however, that the four meetings did not
fall on regular days, owing to the occurrence of feast days on which no
meeting could take place. In the [Greek: kyria ekklêsia] of each month
took place the _Epicheirotonia_ (monthly inquiry) of the state
officials, and if it proved unsatisfactory a trial before the Heliaea
was arranged; the council reported on the general security and the
corn-supply, and read out lists of vacant inheritances and unmarried
heiresses. In the sixth prytany of each year at the [Greek: kyria
ekklêsia] the question whether ostracism should take place that year was
put to the vote. For all meetings it was usual that the Prytaneis should
give five days' notice in the form of a _programma_ (agenda). On
occasions of sudden importance the herald of the council summoned the
people with a trumpet, and sometimes special messengers were despatched
to "bring in" the country people ([Greek: katakalein]).

After the archonship of Solon all Athenians over the age of eighteen
were eligible to attend the assembly, save those who for some reason had
suffered _atimia_ (loss of civil rights). To prevent the presence of any
disqualified persons, six _lexiarchs_ with thirty assistants were
present with the deme-rolls in their hands. These officers superintended
the payment in the 4th century and probably the _toxotae_ (police) also,
whose duty it was before the introduction of pay to drive the people out
of the Agora into the Ecclesia with a rope steeped in red dye which they
stretched out and used as a draw net (see Aristoph. _Acharn._ 22 and
_Eccles._ 378). The introduction of pay, which belongs to the early
years of the 4th century and by the _Constitution_ (c. 41 ad fin.) is
attributed to Agyrrhius, a statesman of the restored democracy, was a
device to secure a larger attendance. The rate rose from one to two
obols and then to three obols (Aristoph. _Eccles._ 300 sqq.), while at
the time of Aristotle it was one and a half drachmas for the [Greek:
kyria ekklêsia] and one drachma for other meetings. Probably those who
were late did not receive payment.

_Procedure._--The proceedings opened with formalities: the purification
by the _peristiarchs_, who carried round slain sucking pigs; the curse
against all who should deceive the people; the appointment (in the 4th
century) of the _proedri_ and their _epistates_ (see BOULE); the report
as to the weather-omens. The assembly was always dismissed if there were
thunder, rain or an eclipse. These formalities over, the Prytaneis
communicated the _probouleuma_ of the council, without which the
Ecclesia could not debate. This recommendation either submitted definite
proposals or merely brought the agenda before the assembly. Its
importance lay largely in the fact that it _explained_ the business in
hand, which otherwise must often have been beyond the grasp of a
miscellaneous assembly. After the reading, a preliminary vote was taken
as to whether the council's report should be accepted _en bloc_. If it
was decided to discuss, the herald called upon people to speak. Any
person, without distinction of age or position, might obtain leave to
speak, but it seems probable that the man who had moved the
recommendation previously in the council would advocate it in the
assembly. The council was, therefore, a check on the assembly, but its
powers were to some extent illusory, because any member of the assembly
(1) might propose an amendment, (2) might draw up a new resolution
founded on the principal motion, (3) might move the rejection of the
motion and the substitution of another, (4) might bring in a motion
asking the council for a recommendation on a particular matter, (5)
might petition the council for leave to speak on a given matter to the
assembly. Voting usually was by show of hands, but in special cases
(ostracism, &c.) by ballot (i.e. by casting pebbles into one of two
urns). The decision of the assembly was called a _psephism_ and had
absolute validity. These decisions were deposited in the Metroön where
state documents were preserved; peculiarly important decrees were
inscribed also on a column (_stele_) erected on the Acropolis. It has
been shown that the power of the council was far from sufficient. The
real check on the vagaries of amateur legislators was the Graphe
Paranomon. Any man was at liberty to give notice that he would proceed
against the mover of a given resolution either before or after the
voting in the Ecclesia. A trial in a Heliastic court was then arranged,
and the plaintiff had to prove that the resolution in question
contravened an existing law. If this contention were upheld by the
court, when the case was brought to it by the Thesmothetae, the
resolution was annulled, and the defendant had to appear in a new trial
for the assessment of the penalty, which was usually a fine, rarely
death. Three convictions under this law, however, involved a certain
loss of rights; the loser could no longer move a resolution in the
Ecclesia. After the lapse of a year the mover of a resolution could not
be attacked. In the 4th century the Graphe Paranomon took the place of
Ostracism (q.v.). In the 5th century it was merely an arrangement
whereby the people sitting as sworn juries ratified or annulled their
own first decision in the Ecclesia.

_Revision of Laws._--In the 4th century, the assembly annually, on the
eleventh day of Hecatombaeon (the first day of the official year), took
a general vote on the laws, to decide whether revision was necessary. If
the decision was in favour of alteration, it was open to any private
citizen to put up notice of amendments. The Nomothetae, a panel selected
by the Prytaneis from the Heliaea, heard arguments for and against the
changes proposed and voted accordingly. Against all new laws so passed,
there lay the Graphe; Paranomon. Thus the Nomothetae, not the Ecclesia,
finally passed the law.

_Judicial Functions._--The Ecclesia heard cases of Probole and
Eisangelia (see GREEK LAW). The Probole was an action against sycophants
and persons who had not kept their promises to the people, or had
disturbed a public festival. The verdict went by show of hands, but no
legal consequences ensued; if the plaintiff demanded punishment he had
to go to the Heliaea which were not at all bound by the previous vote in
the Ecclesia. Cases of Eisangelia in which the penalty exceeded the
legal competence of the council came before the Ecclesia in the form of
a _probouleuma_. To prevent vexatious accusations, it was (at some date
unknown) decided that the accuser who failed to obtain one-fifth of the
votes should be fined 1000 drachmas (£40). (For the procedure in case of
OSTRACISM see that article.)

_Summary._--Thus it will be seen that the Ecclesia, with no formal
organization, had absolute power save for the Graphe Paranomon (which,
therefore, constituted the dicasteries in one sense the sovereign power
in the state). It dealt with all matters home and foreign. Every member
could initiate legislation, and, as has been shown, the power of the
council was merely formal. As against this it must be pointed out that
it was by no means a representative assembly in practice. The phrase
used to describe a very special assembly ([Greek: kataklêtos ekklêsia])
shows that ordinarily the country members did not attend ([Greek:
katakalein] always involving the idea of motion from a distance towards
Athens), and Thucydides says that 5000 was the maximum attendance,
though it must be remembered that he is speaking of the time when the
number of citizens had been much reduced owing to the plague and the
Sicilian expedition. From this we understand the necessity of payment in
the 4th century, although in that period the Ecclesia was supreme
(_Constitution of Athens_, xli. 2). The functions of the Ecclesia thus
differed in two fundamental respects from those which are in modern
times associated with a popular assembly. (1) It did not exercise, at
least in the period as to which we are best instructed, the power of
law-making ([Greek: nomothesia]) in the strict sense. It must be
remembered, however, in qualification of this statement that it
possessed the power of passing _psephismata_ which would in many cases
be regarded as law in the modern sense. (2) The Ecclesia was principally
concerned with the supervision of administration. Much of what we regard
as executive functions were discharged by the Ecclesia.

  With this article compare those on SOLON; BOULE; AREOPAGUS; GREEK LAW,
  and, for other ancient popular assemblies, APELLA; COMITIA. See also
  A.H.J. Greenidge, _Handbook of Greek Constitutional History_ (1896);
  Gilbert, _Greek Constitutional Antiquities_ (trans. Brooks and
  Nicklin, 1895); Schömann, _De comitiis Atheniensium_; L. Schmidt, "De
  Atheniensis reipublicae indole democratica" in _Ind. Lect._ (Marburg,
  1865); J.W. Headlam, _Election by Lot at Athens_ (Cambridge, 1891).
  See also the histories of Greece by Meyer, Busolt, Grote, Evelyn
  Abbott, and J.E. Sandys' edition of the _Constitution of Athens_
  (1892); for a comparative study, E.A. Freeman, _Comparative Politics_.
       (J. M. M.)



ECCLESIASTES (Heb. [Hebrew: Kohelet], _Kohelet_, "Koheleth"; Sept.
[Greek: ekklêsiastês]; Jerome _concionator_), one of the Wisdom Books of
the Old Testament (see WISDOM LITERATURE). The book, as it stands, is a
collection of the discourses, observations and aphorisms of a sage
called Koheleth, a term the precise meaning of which is not certain. The
Greek _ecclesiastes_ means one who takes part in the deliberations of an
assembly (_ecclesia_), a debater or speaker in an assembly (Plato,
_Gorgias_, 452 E), and this is the general sense of the Hebrew word. Its
form (singular feminine) has been supposed to be the adoption or
imitation of the Arabic employment of a fem. sing. as the designation of
a high official person, as is the case in the title _caliph_ (whence the
rendering in the margin of the Revised Version, "Great orator"); but the
adoption of an Arabic idiom is not probable. This usage is not Hebrew;
it is not found either in the Old Testament or in the later (Mishnaic)
Hebrew. The form may have been suggested by that of the Hebrew word for
"wisdom." _Koheleth_, however, is employed in the book not as a title of
wisdom (for "wisdom" is never the speaker), but as the independent name
of the sage. It is intended to represent him as a member of an assembly
(_Kahal_)--not the Jewish congregation, but a body of students or
inquirers, such as is referred to in xii. 9-11, a sort of collegium, of
which he was the head; and as instructor of this body he gives his
criticism of life. The author begins, indeed, with identifying his sage
with King Solomon (i. 12-ii. 11, 12b); but he soon abandons this
literary device, and speaks in his own name. The rendering "preacher"
has a misleading connotation.

In the book as we have it there is no orderly exposition of a theory; it
rather has the appearance of a collection of remarks jotted down by a
pupil (somewhat after the manner of Xenophon's _Memorabilia_), or of
extracts from a sage's notebook. It is, however, characterized
throughout (except in some scribal additions) by a definite thought, and
pervaded by a definite tone of feeling. The keynote is given in the
classic phrase with which the discussion opens and with which it closes:
"Vanity of vanities (i.e. absolute vanity), all[1] is vanity!" Life,
says the author, has nothing of permanent value to offer. His attitude
is one not of bitterness but of calm hopelessness, with an occasional
tinge of disgust or contempt. He fancies that he has tried or observed
everything in human experience, and his deliberate conclusion is that
nothing is worth doing. He believes in an all-powerful but indifferent
God, and is himself an observer of society, standing aloof from its
passions and ambitions, and interested only in pointing out their
emptiness.

This general view is set forth in a number of particular observations.

1. His fundamental proposition is that there is a fixed, unchangeable
order in the world, a reign of inflexible law (i. 4-11, iii. 1-11, 14,
15, vii. 13, viii. 5-9): natural phenomena, such as sunrise and sunset,
recur regularly; for everything in human experience a time has been set;
birth and death, building up and destroying, laughing and weeping,
silence and speech, love and hate, war and peace, are to be regarded not
as utterances of a living, self-directing world, but as incidents in the
work of a vast machine that rolls on for ever; there is an endless
repetition--nothing is new, nothing is lost; if one thinks he has found
something new, inquiry shows that it was in existence long ago; God, the
author of all, seeks out the past in order to make it once more present;
it is impossible to add to or take from the content of the world,
impossible to change the nature of things, to effect any radical
betterment of life; the result is unspeakable weariness--a depressing
series of sights and sounds. No goal or purpose is discoverable in this
eternal round; if the sun rises and goes on his journey through the sky,
it is merely to come back to the place where he rose; rivers flow for
ever into the sea without filling it. To what end was the world created?
It is impossible to say. Such is Koheleth's view of life, and it is
obvious that such a conception of an aimless cosmos is thoroughly
non-Jewish, if we may judge Jewish thought by the great body of the
extant literature.

2. Further, says Koheleth, man is impelled to study the world, but under
the condition that he shall never comprehend it (iii. 11, vii. 23, 24,
viii. 16, 17). As to the meaning of the Hebrew term _olam_ in iii. 11,
there are various opinions, but "world" appears to be the rendering
favoured by the connexion: "God has made everything beautiful in its
time, and has put the _olam_ into men's minds, yet so that they cannot
understand His work": the _olam_, the sum of phenomena, is God's work.
The word is not found in this sense elsewhere in the Old Testament, but
it so occurs in the Mishna (_Pirke Aboth_, iv. 7), and the vocabulary of
Ecclesiastes is admittedly similar to that of the Mishna. Only here in
the Old Testament does it stand as a simple isolated noun; elsewhere it
is the definition of a noun (in "everlasting covenant," &c.), or it is
preceded by a preposition, in the phrases "for ever," "of old," or it
stands alone (sing. or plur.) in the same adverbial sense, "for ever."
The word means first a remote point in past or future, then a future
point without limit of time, then a period of history, and finally the
world considered as a mass of human experiences (cf. [Greek: aiôn]). The
renderings "eternity" and "future" in the present passage are
unsatisfactory; the former has an inappropriate metaphysical
connotation, and yields no distinct sense; the latter does not suit the
connexion, though there is reference to the future elsewhere (ix. 1).
God, the text here declares, has made the world an object of man's
thought, yet so that man can never find out the work that God has done
(iii. 11). The reference seems to be not so much to the variety and
complexity of phenomena as to the impossibility of construing them
rationally or in such a way that man may foresee and provide for his
future. Man is in the clutches of fate (ix. 11, 12): there is no
observable relation between exertion and result in life: the race is not
to the swift nor the battle to the strong; success does not attend
wisdom, knowledge and skill; men are like fish taken in a net or birds
caught in a snare.

3. Human life, Koheleth declares, is unsatisfying. He inquired, he says,
into everything that is done by men under the sun (i. 12-16): God has
inflicted on men a restless desire for movement and work[2], yet life is
but a catalogue of fruitless struggles. He gives a number of
illustrations. In his character of king he tried all the bodily
pleasures of life (ii. 1-11): he had houses, vineyards, gardens, parks,
ponds, forests, servants, flocks and herds, treasures of gold and
silver, singers, wives; all these he set himself to enjoy in a rational
way--indeed, he found a certain pleasure in carrying out his designs,
but, when all was done, he surveyed it only to see that it was weary and
unprofitable. Dropping the rôle of Solomon and speaking as an observer
of life, the author declares (iv. 4) that the struggle for success is
the result of rivalry among men, which has no worthy outcome. The
securing of riches is a fallacious achievement, for often wealth
perishes by some accident (v. 13 f.), or its possessor is unable to
enjoy it (vi. 1-3a), or he has no one to whom to leave it, and he cannot
keep it--naked man comes into the world, naked he goes out. He does not
consider the possibility of deriving enjoyment from wealth by helping
the poor or encouraging learning (this latter, indeed, he looks on as
vanity), and in general he recognizes no obligation on the part of a man
to his fellows. A noteworthy survival of an old belief is found in vi.
3: though a man have the great good fortune to live long and to have
many children, yet, if he have not proper burial the blank darkness of
an untimely birth is better than he: this latter is merely the negation
of existence; the former, it appears to be held, is positive misfortune,
the loss of a desirable place in Sheol, though elsewhere (ix. 5)
existence in Sheol is represented as the negation of real life. It is
not necessary to suppose that the writer has here any particular case in
mind.

If wealth be thus a vain thing, yet a sage might be supposed to find
satisfaction in wisdom, that is, practical good sense and sagacity; but
this also the author puts aside as bringing no lasting advantage, since
a wise man must finally give up the fruit of his wisdom to someone else,
who may be a fool, and in any case the final result for both fools and
wise men is the same--both are forgotten (ii. 12-23). A particular
instance is mentioned (ix. 13-15) of a beleaguered city saved by a wise
man; but the man happened to be poor, and no one remembered him. The
whole constitution of society, in fact, seems to the sage a lamentable
thing: the poor are oppressed, the earth is full of their cries, and
there is no helper (iv. 1); strange social upheavals may be seen: the
poor[3] set in high places, the rich cast down, slaves on horseback,
princes on foot (x. 5-7). He permits himself a sweeping generalization
(vii. 25-28): human beings as a rule are bad: one may occasionally find
a good man, never a good woman--woman is a snare and a curse. He (or an
editor) adds (vii. 29) that this condition of things is due to social
development: man was created upright (Gen. i. 27; Enoch lxix. 11), but
in the course of history has introduced corrupting complications into
life.

4. The natural outcome of these experiences of the author is that he
cannot recognize a moral government of the world. He finds, like Job,
that there are good men who die prematurely notwithstanding their
goodness, and bad men who live long notwithstanding their badness (vii.
15), though long life, it is assumed, is one of the great blessings of
man's lot; and in general there is no moral discrimination in the
fortunes of men (viii. 14, ix. 2).

5. There is no sacredness or dignity in man or in human life: man has no
pre-eminence over beasts, seeing that he and they have the same final
fate, die and pass into the dust, and no one knows what becomes of the
spirit, whether in man's case it goes up to heaven, and in the case of
beasts goes down into Sheol--death is practically the end-all; and so
poor a thing is life that the dead are to be considered more fortunate
than the living, and more to be envied than either class is he who never
came into existence (iv. 2, 3). It is a special grievance that the
wicked when they die are buried with pomp and ceremony, while men who
have acted well are forgotten[4] in the city (viii. 10).

6. That the author does not believe in a happy or active future life
appears in the passage (iv. 2, 3) quoted above. The old Hebrew view of
the future excluded from Sheol the common activities of life and also
the worship of the national god (Isa. xxxviii. 18); he goes even beyond
this in his conception of the blankness of existence in the underworld.
The living, he says, at least know that they shall die, but the dead
know nothing--the memory of them, their love, hate and envy, perishes,
they have no reward, no part in earthly life (ix. 5, 6); there is
absolutely no knowledge and no work in Sheol (ix. 10). His conclusion is
that men should do now with all their might what they have to do; the
future of man's vital part, the spirit, is wholly uncertain.

7. His conception of God is in accord with these views. God for him is
the creator and ruler of the world, but hardly more; he is the master of
a vast machine that grinds out human destinies without sympathy with man
and without visible regard for what man deems justice--a being to be
acknowledged as lord, not one to be loved. There can thus be no social
contact between man and God, no communion of soul, no enthusiasm of
service. Moral conduct is to be regulated not by divine law (of this
nothing is said) but by human experience. The author's theism is cold,
spiritless, without influence on life.

If now the question be asked what purpose or aim a man can have, seeing
that there is nothing of permanent value in human work, an answer is
given which recurs, like a refrain, from the beginning to the end of the
book, and appears to be from the hand of the original author: after
every description of the vanity of things comes the injunction to enjoy
such pleasures as may fall to one's lot (ii. 24, 25, iii. 12, 13, 22, v.
18, 19, viii. 15, ix. 7-10, xi. 7-xii. 7). Elsewhere (ii.), it is true,
it is said that there is no lasting satisfaction in pleasure; but the
sage may mean to point out that, though there is no permanent outcome to
life, it is the part of common-sense to enjoy what one has. The
opportunity and the power to enjoy are represented as being the gift of
God; but this statement is not out of accord with the author's general
position, which is distinctly theistic. All the passages just cited,
except the last (xi. 7-xii. 7), are simple and plain, but the bearing of
the last is obscured by interpolations. Obviously the purpose of the
paragraph is to point out the wisdom of enjoying life in the time of
youth while the physical powers are fresh and strong, and the impotency
of old age has not yet crept in. Omitting xi. 8c, 9b, 10b, xii. 1a, the
passage will read: "Life is pleasant in the bright sunshine--however
long a man may live, he must be cheerful always, only remembering that
dark days will come. Let the young man enjoy all the pleasures of youth,
putting away everything painful, before the time comes when his bodily
powers decay and he can enjoy nothing." To relieve the apparent
Epicureanism of this passage, an editor has inserted reminders of the
vanity of youthful pleasures, and admonitions to remember God and His
judgment. The author, however, does not recommend dissipation, and does
not mean to introduce a religious motive--he offers simply a counsel of
prudence. The exhortation to remember the Creator in the days of youth,
though it is to be retained in the margin as a pious editorial addition,
here interrupts the line of thought. In xii. 1a some critics propose to
substitute for "remember thy Creator" the expression of xi. 9, "let thy
heart cheer thee"; but the repetition is improbable. Others would read:
"remember thy cistern" (Bickell), or "thy well" (Haupt), that is, thy
wife. The wife is so called in Prov. v. 15-19 in an elaborate poetical
figure (the wife as a source of bodily pleasure), in which the reference
is clear from the context; but there is no authority, in the Old
Testament or in other literature of this period, for taking the term as
a simple prose designation of a wife. Nor would this reference to the
wife be appropriate in the connexion, since the writer's purpose is
simply to urge men to enjoy life while they can. The paragraph (and the
original book) concludes with a sustained and impressive figure, in
which the failing body of the old man is compared to a house falling
into decay: first, the bodily organs (xii. 3, 4a): the keepers of the
house (the arms and hands) tremble, the strong men (the legs and perhaps
the backbone) are bent, the grinding women (the teeth) cease to work,
those that look out of the windows (the eyes) are darkened, the
street-doors are shut, the sound of the mill being low (apparently a
summary statement of the preceding details: communication with the outer
world through the senses is cut off, the performance of bodily functions
being feeble); the rest of v. 4 may refer to the old man's inability to
make or hear music: in the house there is no sound of birds[5] or of
singers, there are none of the artistic delights of a well-to-do
household; further (v. 5a) the inmates of the house fear dangers from
all powerful things and persons (the old man is afraid of everything),
the almond tree blossoms (perhaps the hair turns white). The two next
clauses are obscure.[6] Then comes the end: man goes to his everlasting
home; the dust (the body) returns to the earth whence it came (Gen. ii.
7), and the breath of life, breathed by God into the body, returns to
him who gave it. This last clause does not affirm the immortality of the
soul; it is simply an explanation of what becomes of the vital principle
(the "breath of life" of Gen. ii. 7); its positive assertion is not in
accord with the doubt expressed in iii. 21 ("who knows whether the
spirit of man goes upward?"), and it seems to be from another hand than
that of the author of the original book.

There are other sayings in the book that appear to be at variance with
its fundamental thought. Wisdom is praised in a number of passages (iv.
13, vii. 5, 11, 12, 19, viii. 1, ix. 16, 17, x. 2, 3), though it is
elsewhere denounced as worthless. It may be said that the author, while
denying that wisdom (practical sagacity and level-headedness) can give
permanent satisfaction, yet admits its practical value in the conduct of
life. This may be so; but it would be strange if a writer who could say,
"in much wisdom is much grief," should deliberately laud wisdom. The
question is not of great importance and may be left undecided. It may be
added that there are in the book a number of aphorisms about fools (v.
3[4], vii. 5, 6, x. 1-3, 12-15) quite in the style of the book of
Proverbs, some of them contrasting the wise man and the fool; these
appear to be the insertions of an editor. Further, it may be concluded
with reasonable certainty that the passages that affirm a moral
government of the world are additions by pious editors who wished to
bring the book into harmony with the orthodox thought of the time. Such
assertions as those of ii. 26 (God gives joy to him who pleases him, and
makes the sinner toil to lay up for the latter), viii. 12 (it shall be
well with those that fear God, but not with the wicked), xii. 13 f.
(man's duty is simply to obey the commands of God, for God will bring
everything into judgment) are irreconcilable with the oft-repeated
statement that there is no difference in the earthly lots of the
righteous and the wicked, and no ethical life after death.

Many practical admonitions and homely aphorisms are scattered through
the book: iv. 5, quiet is a blessing; iv. 9-12, two are better than one;
iv. 17 (Eng. v. 1), be reverent in visiting the house of God (the temple
and the connected buildings)--to listen (to the service of song or the
reading of Scripture) is better than to offer a foolish (thoughtless)
sacrifice; v. 1 (2), be sparing of words in addressing God; v. 1-5
(2-6), pay your vows--do not say to the priest's messenger that you made
a mistake; vii. 2-4, sorrow is better than mirth; vii. 16-18, be not
over-righteous (over-attentive to details of ritual and convention) or
over-wicked (flagrantly neglectful of established beliefs and customs);
here "righteous" and "wicked" appear to be technical terms designating
two parties in the Jewish world of the 2nd and 1st centuries B.C., the
observers and the non-observers of the Jewish ritual law; these parties
represent in a general way the Pharisees and the Sadducees; viii. 2-4,
x. 20, it is well to obey kings and to be cautious in speaking about
them, for there are talebearers everywhere; vii. 20, no man is free from
sin; vii. 21, do not listen to all that you may overhear, lest you hear
yourself ill spoken of; ix. 4, a living dog is better than a dead lion;
xi. 1-6, show prudence and decision in business; do not set all your
goods on one venture; act promptly and hope for the best. At the close
of the book (xii. 9-12) there are two observations that appear to be
editorial recommendations and cautions. First, Koheleth is endorsed as
an industrious, discriminating and instructive writer. Possibly this is
in reply to objections that had been made to what he had written. There
follows an obscure passage (v. 11) which seems to be meant as a
commendation of the teaching of the sages in general: their words are
said to be like goads (inciting to action) and like nails driven in a
building (giving firmness to character); they issue from masters of
assemblies,[7] heads of academies (but not of the Sanhedrin). The
succeeding clause "they are given from one shepherd" may refer to a
collection or revision by one authoritative person, but its relevancy is
not obvious. The "shepherd" cannot be God (Gen. xlix. 24; Ps. xxiii. 1);
the poetical use of the word would not be appropriate here. The clause
is possibly a gloss, a comment on the preceding expression. A caution
against certain books is added (v. 12), probably works then considered
harmful (perhaps philosophic treatises), of which, however, nothing
further is known.

_Composition of the Book._--If the analysis given above is correct, the
book is not a unit; it contains passages mutually contradictory and not
harmonizable. Various attempts have been made to establish its unity.
The hypothesis of "two voices" is now generally abandoned; there is no
indication of a debate, of affirmations and responses. A more plausible
theory is that the author is an honest thinker, a keen observer and
critic of life, who sees that the world is full of miseries and unsolved
problems, regards as futile the attempts of his time to demonstrate an
ethically active future life, and, recognizing a divine author of all,
holds that the only wise course for men is to abandon the attempt to get
full satisfaction out of the struggle for pleasure, riches and wisdom,
and to content themselves with making the best of what they have. This
conception of him is largely true, as is pointed out above, but it does
not harmonize the contradictions of the book, the discrepancies between
the piety of some passages and the emotional indifference toward God
shown in others. Other of the Biblical Wisdom books (Job, Proverbs) are
compilations--why not this? It is not necessary to multiply authors, as
is done, for example, by Siegfried, who supposes four principal writers
(a pessimistic philosopher, an Epicurean glossator, a sage who upholds
the value of wisdom, and an orthodox editor) besides a number of
annotators; it is sufficient to assume that several conservative scribes
have made short additions to the original work. Nor is it worth while to
attempt a logical or symmetrical arrangement of the material. It has
been surmised (by Bickell) that the sheets of the original codex became
disarranged and were rearranged incorrectly;[8] by other critics
portions of the book are transferred hither and thither; in all cases
the critic is guided in these changes by what he conceives to have been
the original form of the book. But it is more probable that we have it
in the form in which it grew up--a series of observations by the
original author with interspersed editorial remarks; and it is better to
preserve the existing form as giving a record of the process of growth.

_Date._--As to the date of the book, though there are still differences
of opinion among scholars, there is a gradual approach to a consensus.
The Solomonic authorship has long since been given up: the historical
setting of the work and its atmosphere--the silent assumption of
monotheism and monogamy, the non-national tone, the attitude towards
kings and people, the picture of a complicated social life, the strain
of philosophic reflection--are wholly at variance with what is known of
the 10th century B.C. and with the Hebrew literature down to the 5th or
4th century B.C. The introduction of Solomon, the ideal of wisdom, is a
literary device of the later time, and probably deceived nobody. The
decisive considerations for the determination of the date are the
language, the historical background and the thought. The language
belongs to the post-classical period of Hebrew. The numerous Aramaisms
point to a time certainly not earlier than the 4th century B.C., and
probably (though the history of the penetration of Aramaic into Hebrew
speech is not definitely known) not earlier than the 3rd century. More
than this, there are many resemblances between the dialect of Koheleth
and that of Mishna. Not only are new words employed, and old words in
new significations, but the grammatical structure has a modern
stamp--some phrases have the appearance of having been translated out of
Aramaic into Hebrew. By about the beginning of our era the Jews had
given up Hebrew and wrote in Aramaic; the process of expulsion had been
going on, doubtless, for some time; but comparison with the later extant
literature (_Chronicles_, the Hebrew _Ecclesiasticus_ or _Ben-Sira_,
_Esther_) makes it improbable that such Hebrew as that of Koheleth would
have been written earlier than the 2nd century B.C. (for details see
Driver's _Introduction_). The general historical situation, also,
presupposed or referred to, is that of the period from the year 200 B.C.
to the beginning of our era; in particular, the familiar references to
kings as a part of the social system, and to social dislocations
(servants and princes changing places, x. 7), suggest the troublous time
of the later Greek and the Maccabean rulers, of which the history of
Josephus gives a good picture.

The conception of the world and of human life as controlled by natural
law, a naturalistic cosmos, is alien not only to the prophetic and
liturgical Hebrew literature but also to Hebrew thought in general.
Whether borrowed or not, it must be late; and its resemblance to Greek
ideas suggests Greek influence. The supposition of such influence is
favoured by some critics (Tyler, Plumptre, Palm, Siegfried, Cheyne in
his _Jewish Religious Life after the Exile_, and others), rejected by
some (Zeller, Renan, Kleinert and others). This disagreement comes
largely from the attempts made to find definitely expressed Greek
philosophical dogmas in the book; such formulas it has not, but the
general air of Greek reflection seems unmistakable. The scepticism of
Koheleth differs from that of Job in quality and scope: it is deliberate
and calm, not wrung out by personal suffering; and it relates to the
whole course and constitution of nature, not merely to the injustices of
fortune. Such a conception has a Greek tinge, and would be found in
Jewish circles, probably, not before the 2nd century B.C.

A precise indication of date has been sought in certain supposed
references or allusions to historical facts. The mention of persons who
do not sacrifice or take oaths (ix. 2) is held by some to point to the
Essenes; if this be so, it is not chronologically precise, since we have
not the means of determining the beginning of the movement of thought
that issued in Essenism. So also the coincidences of thought with
_Ben-Sira_ (_Ecclesiasticus_) are not decisive: cf. iii. 14 with _B.S._
xviii. 6; v. 2-6 (3-7) with _B.S._ xxxiv. 1-7; vii. 19 with _B.S._
xxxvii. 14; x. 8 with _B.S._ xxvii. 26a; xi. 10 with _B.S._ xxx. 21;
xii. 10, 11 with _B.S._ xxxix. 2 ff., xii. 13 with _B.S._ xliii. 27; if
there be borrowing in these passages, it is not clear on which side it
lies; and it is not certain that there is borrowing--the thoughts may
have been taken independently by the two authors from the same source.
In any case, since _Ben-Sira_ belongs to about 180 B.C., the date of
Koheleth, so far as these coincidences indicate it, would not be far
from 200 B.C. The contrast made in x. 16 f. between a king who is a boy
and one who is of noble birth may allude to historical persons. The
antithesis is not exact; we expect either "boy and mature man" or
"low-born and high-born." The "child" might be Antiochus V. (164 B.C.),
or Ptolemy V., Epiphanes (204 B.C.), but the reference is too general to
be decisive. The text of the obscure passage iv. 13-16 is in bad
condition, and it is only by considerable changes that a clear meaning
can be got from it. The two personages--the "old and foolish king" and
the "poor and wise youth"--have been supposed (by Winckler) to be
Antiochus Epiphanes (175-164 B.C.) and Demetrius (162-150 B.C.), or (by
Haupt) Antiochus and the impostor Alexander Balas (150-146 B.C.), or (by
others) Demetrius and Alexander; in favour of Alexander as the "youth"
it may be said that he was of obscure origin, was at first popular, and
was later abandoned by his friends. Such identifications, however, do
not fix the date of the book precisely; the author may have referred to
events that happened before his time. The reign of Herod, a period of
despotism and terror, and of strife between Jewish religious parties, is
preferred by some scholars (Grätz, Cheyne and others) as best answering
to the social situation depicted in the book, while still others (as
Renan) decide for the reign of Alexander Jannaeus (104-78 B.C.). The
data are not numerous and distinct enough to settle the question beyond
determining general limits: for reasons given above the book can hardly
have been composed before about 200 B.C., and if, as is probable, a
Septuagint translation of it was made (though the present Septuagint
text shows the influence of Aquila), it is to be put earlier than 50
B.C. Probably also, its different parts are of different dates.

Of the author nothing is known beyond the obvious fact that he was a man
of wide observation and philosophic thought, of the Sadducean type in
religion, but non-Jewish in his attitude toward life. He was, doubtless,
a man of high standing, but neither a king nor a high-priest, certainly
not the apostate priest Alcimus (1 Macc. vii. ix.); nor was he
necessarily a physician--there are no details in ch. xii. or elsewhere
that any man of good intelligence might not know. The book is written in
prose, some of which is rhythmical, with bits of verse here and there:
thus i. 2-11 is balanced prose, 12-14 plain prose, 15 a couplet, i.
16-ii. 25 simple prose, vii. contains a number of poetical aphorisms,
and so on. Some of the verses are apparently from the author, some from
editors.

The fortunes of the book are not known in detail, but it is clear that
its merciless criticism of life and its literary charm made it popular,
while its scepticism excited the apprehensions of pious conservatives.
Possibly the _Wisdom of Solomon_ (c. 50 B.C.) was written partly as a
reply to it. The claim of sacredness made for it was warmly contested by
some Jewish scholars. In spite of the relief afforded by orthodox
additions, it was urged that its Epicurean sentiments contradicted the
Torah and favoured heresy. Finally, by some process of reasoning not
fully recorded, the difficulties were set aside and the book was
received into the sacred canon; Jerome (on Eccl. xii. 13, 14) declares
that the decisive fact was the orthodox statement at the end of the
book: the one important thing is to fear God and keep His commandments.
The probability is that the book had received the stamp of popular
approbation before the end of the 1st century of our era, and the
leading men did not dare to reject it. It is not certain that it is
quoted in the New Testament, but it appears to be included in Josephus'
list of sacred books.

  LITERATURE.--For the older works see Zöckler (in Lange's _Comm._); for
  Jewish commentaries see Zedner, _Cat. of Heb. books in Libry. of Brit.
  Mus._ (1867), and for the history of the interpretations, C.D.
  Ginsburg, _Coheleth_ (1861). _Introductions_ of A. Kuenen, S.R.
  Driver, Cornhill, König. Articles in Herzog-Hauck, _Realencykl._ (by
  P. Kleinert); Hastings, _Dict. Bible_ (by A.S. Peake); T.K. Cheyne,
  _Encycl. Bibl._ (by A.B. Davidson); _Jew. Encycl._ (by D.S.
  Margoliouth). Commentaries: F. Hitzig (1847); C.D. Ginsburg (1861); H.
  Grätz (1871); Tyler (1874); Delitzsch (1875); E.H. Plumptre (1881);
  C.H.H. Wright (1883); Nowack, revision of Hitzig (1883); Volck (in
  Strack u. Zöckler's _Kurzgef. Komm._, 1889); Wildeboer (in Marti's
  _Kurzer Hand-Comm._, 1898); C. Siegfried (in W. Nowack's _Handkomm._,
  1898); Oort (in _De Oude Test._, 1899). Other works: C. Taylor, _Dirge
  of Koh._ (1874); Wünsche, _Midrash_ on Koh. (in his _Biblioth.
  rabbin._, 1880); E. Renan, _L'Ecclésiaste_ (1882); Bickell, _Der
  Prediger_ (1884) and _Kohel.-Untersuchungen_ (1886; Engl. by E.J.
  Dillon, _Sceptics of Old Test._, 1895); Schiffer, _Das Buch Koh. nach
  d. Auffass. d. Weisen d. Talmuds_, &c. (1884); A. Palm, _Qoh. u. d.
  nach-aristotel. Philosophie_ (1885) and _Die Qoh.-Lit._ (1886); E.
  Pfleiderer, _Die Phil. d. Heraklit_, &c. (1886); Cheyne, _Job and
  Solomon_ (1887) and _Jew. Relig. Life_, &c. (1898); W. Euringer, _Der
  Masorahtext d. Koh._ (1890); W.T. Davison, _Wisdom-Lit. of Old Test._
  (1894); H. Winckler, in his _Altorient. Forschungen_ (1898); J.F.
  Genung, _Words of Koh._ (Boston, Mass., 1904); P. Haupt,
  _Ecclesiastes_ (Baltimore, 1905). The rabbinical discussions of the
  book are mentioned in _Shabbath_, 30b; _Megilla_, 7a; _Eduyoth_, v. 3;
  _Mishna Yadaim_, iii. 5, iv. 6; _Midrash Koheleth_ (on xi. 9), _Aboth
  d' Rab. Nathan_, i.     (C. H. T.*)


FOOTNOTES:

  [1] The Hebrew has the definite article, "the whole," [Greek: to
    pan].

  [2] In fact, he suggests, a curse, as in Gen. iii. 17-19, though with
    a wider sweep than that passage has in mind.

  [3] The text has "folly," but the parallelism and v. 7 point to
    social, not intellectual, conditions, and a slight change ([Hebrew:
    haskel] for [Hebrew: misken]) gives the sense "poor."

  [4] The Septuagint has less well: "They (the wicked) are praised in
    the city."

  [5] The clause is obscure; literally "he (or, one) rises at (?) the
    voice of the bird," usually understood to refer to the old man's
    inability to sleep in the morning; but this is not a universal trait
    of old age, and besides, a reference to affairs in the house is to be
    expected; the Hebrew construction also is of doubtful correctness. A
    change of the Hebrew text seems necessary; possibly we should read
    [Hebrew: ishpal kol], "low is the voice," instead of [Hebrew: yakum
    lekol] "he rises up at the voice."

  [6] The second is perhaps to be read: "the caper-berry blooms" (white
    hair); usually "the caper-berry loses its appetizing power"; Eng.
    Auth. Vers. "desire shall fail." For the meaning of the word _abyona_
    ("caper-berry," not "desire" or "poverty"), see art. by G.F. Moore in
    _Journ. of Bibl. Lit._ x. 1 (Boston, Mass., 1891).

  [7] This is the Talmudic understanding of the Hebrew expression
    (Jerus. Sanhed. 10, 28a, cf. Sanhed. 12a; see Ecclus. xxxix. 2).
    There is no good authority for the renderings "collectors of maxims,"
    "collections of maxims."

  [8] It is not certain that the codex form was in use in Palestine or
    in Egypt as early as the 2nd or the 1st century B.C.



ECCLESIASTICAL COMMISSIONERS, in England, a body corporate, whose full
title is "Ecclesiastical and Church Estates Commissioners for England,"
invested with very important powers, under the operation of which
extensive changes have been made in the distribution of the revenues of
the Established Church. Their appointment was one of the results of the
vigorous movements for the reform of public institutions which followed
the Reform Act of 1832. In 1835 two commissions were appointed "to
consider the state of the several dioceses of England and Wales, with
reference to the amount of their revenues and the more equal
distribution of episcopal duties, and the prevention of the necessity of
attaching by commendam to bishoprics certain benefices with cure of
souls; and to consider also the state of the several cathedral and
collegiate churches in England and Wales, with a view to the suggestion
of such measures as might render them conducive to the efficiency of the
established church, and to provide for the best mode of providing for
the cure of souls, with special reference to the residence of the clergy
on their respective benefices." And it was enacted by an act of 1835
that during the existence of the commission the profits of dignities and
benefices without cure of souls becoming vacant should be paid over to
the treasurer of Queen Anne's Bounty. In consequence of the
recommendation of these commissioners, a permanent commission was
appointed by the Ecclesiastical Commissioners Act 1836 for the purpose
of preparing and laying before the king in council such schemes as
should appear to them to be best adapted for carrying into effect the
alterations suggested in the report of the original commission and
recited in the act. The new commission was constituted a corporation
with power to purchase and hold lands for the purposes of the act,
notwithstanding the statutes of mortmain. The first members of the
commission were the two archbishops and three bishops, the lord
chancellor and the principal officers of state, and three laymen named
in the act.

The constitution of the commission was amended by the Ecclesiastical
Commissioners Act 1840 and subsequent acts, and now consists of the two
archbishops, all the bishops, the deans of Canterbury, St Paul's and
Westminster, the lord chancellor, the lord president of the council, the
first lord of the treasury, the chancellor of the exchequer, the home
secretary, the lord chief justice, the master of the rolls, two judges
of the admiralty division, and certain laymen appointed by the crown and
by the archbishop of Canterbury. The lay commissioners are required to
be "members of the Church of England, and to subscribe a declaration to
that effect." The crown also appoints two laymen as church estates
commissioners, and the archbishop of Canterbury one. These three are the
joint treasurers of the commission, and constitute, along with two
members appointed by the commission, the church estates committee,
charged with all business relating to the sale, purchase, exchange,
letting or management of any lands, tithes or hereditaments. The
commission has power to make inquiries and examine witnesses on oath.
Five commissioners are a quorum for the transaction of business,
provided two of them are church estates commissioners; two
ecclesiastical commissioners at least must be present at any proceeding
under the common seal, and if only two are present they can demand its
postponement to a subsequent meeting. The schemes of the commission
having, after due notice to persons affected thereby, been laid before
the king in council, may be ratified by orders, specifying the times
when they shall take effect, and such orders when published in the
_London Gazette_ have the same force and effect as acts of parliament.

  The recommendations of the commission recited in the act of 1836 are
  too numerous to be given here. They include an extensive rearrangement
  of the dioceses, equalization of episcopal income, providing
  residences, &c. By the act of 1840 the fourth report of the original
  commissioners, dealing chiefly with cathedral and collegiate churches,
  was carried into effect, a large number of canonries being suspended,
  and sinecure benefices and dignities suppressed.

  The emoluments of these suppressed or suspended offices, and the
  surplus income of the episcopal sees, constitute the fund at the
  disposal of the commissioners. By an act of 1860, on the avoidance of
  any bishopric or archbishopric, all the land and emoluments of the
  see, except the patronage and lands attached to houses of residence,
  become, by order in council, vested in the commissioners, who may,
  however, reassign to the see so much of the land as may be sufficient
  to secure the net annual income named for it by statute or order. All
  the profits and emoluments of the suspended canonries, &c., pass over
  to the commissioners, as well as the separate estates of those
  deaneries and canonries which are not suspended. Out of this fund the
  expenses of the commission are to be paid, and the residue is to be
  devoted to increasing the efficiency of the church by the augmentation
  of the smaller bishoprics and of poor livings, the endowment of new
  churches, and employment of additional ministers.

  The substitution of one central corporation for the many local and
  independent corporations of the church, so far at least as the
  management of property is concerned, was a constitutional change of
  great importance, and the effect of it undoubtedly was to correct the
  anomalous distribution of ecclesiastical revenues by equalizing
  incomes and abolishing sinecures. At the same time it was regarded as
  having made a serious breach in the legal theory of ecclesiastical
  property. "The important principle," says Cripps, "on which the
  inviolability of the church establishment depends, that the church
  generally possesses no property as a corporation, or which is
  applicable to general purposes, but that such particular
  ecclesiastical corporation, whether aggregate or sole, has its
  property separate, distinct and inalienable, according to the
  intention of the original endowment, was given up without an effort to
  defend it" (_Law Relating to the Church and Clergy_, p. 46).



ECCLESIASTICAL JURISDICTION. This phrase in its primary sense imports
not jurisdiction over ecclesiastics, but jurisdiction exercised by
ecclesiastics over other ecclesiastics and over the laity.
"Jurisdiction" is a word borrowed from the jurists which has acquired a
wide extension in theology, wherein, for example, it is frequently used
in contradistinction to "order," to express the right to administer
sacraments as something superadded to the _power_ to celebrate them. So
it is used to express the territorial or other limits of ecclesiastical,
executive or legislative authority. Here it is used, in the limited
sense defined by an American Court, as "the authority by which judicial
officers take cognizance of and decide causes."


  Origin of ecclesiastical jurisdiction.

Such authority in the minds of lay Roman lawyers who first used this
word "jurisdiction" was essentially temporal in its origin and in its
sphere. The Christian Church transferred the notion to the spiritual
domain as part of the general idea of a Kingdom of God correlative, on
the spiritual side of man upon earth, to the powers, also ordained of
God, who had dominion over his temporal estate (see CANON LAW). As the
Church in the earliest ages had executive and legislative power in its
own spiritual sphere, so also it had "judicial officers," "taking
cognizance of and deciding causes." Only before its union with the
State, its power in this direction, as in others, was merely over the
spirits of men. Coercive temporal authority over their bodies or estates
could only be given by concession from the temporal prince. Moreover,
even spiritual authority over members of the Church, i.e. baptized
persons, could not be exclusively claimed as _of right_ by the Church
tribunals, if the subject matter of the cause were purely temporal. On
the other hand, it is clear that _all_ the faithful were subject to
these courts (when acting within their own sphere), and that, in the
earliest times, no distinction was made in this respect between clergy
and laity.

The fundamental principle of ecclesiastical jurisdiction with its
"sanction" of excommunication will be found in Christ's words in Matt.
xviii. 15-18. A very early example of criminal spiritual jurisdiction
exercised by St Paul is found in the case of the incestuous Corinthian
(1 Cor. v.). We find later the same apostle exercising like jurisdiction
in the cause of Hymenaeus and Alexander (1 Tim. i. 20). After the time
of the Apostles, we find this criminal jurisdiction exercised by the
bishops individually over their respective "subjects"--doubtless with
the advice of their presbyters according to the precept of St Ignatius
(c. 110). As neighbouring dioceses coalesced into "provinces" and
provinces into larger districts (corresponding to the civil "dioceses"
of the later Roman Empire), the provincial synods of bishops and the
synods of the larger districts acquired a criminal jurisdiction, still
purely spiritual, of their own. At first this was "original" and mainly
(although not exclusively) over bishops (of the province or larger
district). The beginnings of an appellate jurisdiction in the cases of
clerics and laymen may be traced before the conversion of the Empire.
The bishop over whom the synod of neighbouring bishops had exercised
jurisdiction had no formal right of appeal; but sometimes bishops in
other parts of the Church would refuse to acknowledge the local
synodical sentence and would communicate with a bishop whom they deemed
unjustly deposed. The theory, as expressed in legal phrase by St Cyprian
in the 3rd century, was that the apostolic power of delegated
sovereignty from the Lord, alike legislative and judicial, was held in
joint-tenancy by the whole body of Catholic bishops. In both capacities,
however, a certain undefined pre-eminence was conceded to the occupants
of "Apostolic" sees, i.e. sees traditionally founded by Apostles, or of
sees with a special secular position.

Even before the edict of Milan, at least as early as the latter half of
the 3rd century, the spiritual sentences of deposition from office had
sometimes indirect temporal consequences recognized by the secular
courts. The classical example is the case of Paul of Samosata, bishop of
Antioch. It would seem that, in the intervals of persecution, some
rights of property were recognized in the Christian Church and its
officers; although the Church was an illegal society. After some
previous abortive trials, Paul of Samosata was deposed and
excommunicated, in 269, by a great synod of the Antiochene district.
Paul, notwithstanding his deposition, kept possession of the episcopal
residence. The local church sought recovery of it before the tribunals
of the Empire. The judicial authorities requested a rescript from the
emperor Aurelian for the decision of the cause. Aurelian referred the
matter to the bishop of Rome and the bishops of Italy, who gave their
award in favour of the Antiochene Church.


  Temporal Jurisdiction of the Church.

Side by side with this which we may call criminal jurisdiction--none the
less real or coercive because its sanctions were purely spiritual--there
grew up a quasi-jurisdiction in causes entirely temporal, based upon the
free consent of the parties to accept the arbitration of the bishop.
This system had also its roots in the New Testament (see Matt, xviii.
15-17 and 1 Cor. vi. 1-8). In the matter of criminal jurisdiction we
paused for a moment at the edict of Milan; but we may at once trace this
second or civil branch of episcopal judicature or quasi-judicature down
as far as the reign of Charlemagne, when it underwent a fundamental
change, and became, if _either_ litigant once chose, no longer a matter
of consent but of right.

Constantine decreed that judgment in causes might be passed by bishops
when litigants preferred their adjudication to that of the secular
courts (see his epistle to the Numidian bishops and _Cod. Theodos. Tit.
de Episcopis_). The episcopal judgment was to be equivalent to that of
the emperor and irreversible, and the civil authorities were to see to
its execution. Saints Ambrose and Augustine both spent days in deciding
temporal causes. Honorius, in the West, at the end of the 4th century,
made a constitution providing that if any desired to litigate before the
bishops they should not be forbidden, but that in civil matters the
prelates should render judgment in the manner of arbitrators by consent
(_Cod._ 1, _Tit._ iv.). Where the faithful had had recourse to the
bishop, no appeal was to be allowed, and the judges were to command
execution of the episcopal decree. A quarter of a century later,
however, Valentinian III. in the West expressly provided that bishops
were not to be permitted to be judges (that is, of course, in temporal
causes), save by the consent of the parties. This legislation was,
substantially, adopted by Justinian.

On the revival of the Western Empire, however, Charlemagne, in the
beginning of the 9th century, under the mistaken belief that he was
following the authority of Constantine I. and Theodosius I., took a
great step forward, by which the bishop ceased to be a mere legally
indicated arbitrator by consent in secular causes, and became a real
judge. By a capitulary he provided that either litigant, without the
consent of the other party, and not only at the beginning of a suit but
at any time during its continuance, might take the cause from lay
cognizance and transfer it to the bishop's tribunal. He re-enacted the
prohibition of appeal.

It should be remembered that, from the latter part of the 3rd century,
the leading bishops had generally been trained in secular learning. St
Cyprian, St Ambrose and St Augustine, St Paulinus of Nola and St John
Chrysostom had practised law as teachers or advocates. St Ambrose and St
Paulinus had even held high administrative and judicial offices.


  Roman empire from Constantine.

To return to the evolution of ecclesiastical jurisdiction from the time
of Constantine. With the "Nicene period" came a great development on the
criminal side. A system begins to be formed, and the secular arm
supports the decrees of the Church. The first trace of system is in the
limited right of appeal given by the first oecumenical council of Nicaea
and its provision that episcopal sentences or those of provincial synods
on appeal were to be recognized throughout the world. The fifth canon
provides that those, whether clerics or laymen, who are cut off from
communion in any particular province are not to be admitted thereto
elsewhere. Still examination must be had whether persons have been
expelled from the congregation by any episcopal small-mindedness
([Greek: mikropsychia]), or contentious spirit, or such-like harshness
([Greek: aêdia]). That this may be conveniently inquired into, synods
are to be held, three in every year, in each province, and questions of
this kind examined. There is to be no "stay of execution"; the episcopal
sentence is to prevail until the provincial synod otherwise decide. It
will be noticed that as yet no provision is made for appeals by
_bishops_ from provincial synods sitting in first instance.

The edicts of Milan had only admitted the Christian Church among the
number of lawful religions; but the tendency (except in the time of
Julian) was towards making it the only lawful religion. Hence the
practice, immediately after Nicaea I., of superadding banishment by the
emperor to synodical condemnation. The dogmatic decrees of Nicaea I.
were at once enforced in this temporal manner. On the other hand, the
Arian reaction at court worked its objects (see Pusey, _Councils of the
Church_) by using the criminal spiritual jurisdiction of synods against
the Catholics--often packing the synods for the purpose. The acts of
councils of this age are full of the trials of bishops not only for
heresy but for immorality and common law crimes. The accusations are
frequently unfounded; but the trials are already conducted in a certain
regular forensic form. The secular authorities follow the precedent of
Nicaea I. and intervene to supplement the spiritual sentence by
administrative penalties. Sometimes an imperial officer of high rank
(as, e.g. a "count") is present at the synod, as an assessor to maintain
order and advise upon points of procedure. Leading examples may be found
in the various prosecutions of St Athanasius, in whose case also there
is the germ of an appeal, _tanquam ab abusu_. It has been contended
that, according to later and more formulated jurisprudence, such an
appeal would have lain, since the trial at Tyre was not concerned with
purely spiritual matters (see the case in Hefele, _Councils_, in loc.).

The trial of St Athanasius led to extensions of the right of appeal.
This was favoured by the development of the greater sees into positions
of great administrative dignity, shortly to be called "patriarchal." A
synod was held at Rome, attended by bishops from various regions, which
reversed the original judgment of the synod of Tyre which had condemned
Athanasius. A much larger synod at Antioch, gathered only from the East,
on the other hand, confirmed that judgment. This last synod did
something to systematize the criminal procedure of the Church, and its
legislation has been always received.

This legislation marks another step forward. Deposition of a bishop by a
synod, or of a priest or deacon by his bishop, is to take effect even
pending an appeal, and a cleric continuing his functions after sentence
in first instance is to lose all right of appeal. The appeal given by
Nicaea I. to clerics and laymen from episcopal excommunications is
extended. The synod may restore them if convinced of the justice of
their cause (and not merely in cases of [Greek: aêdia]). A bishop may
appeal to a great assembly of bishops. Any bishop, priest or deacon
"importuning" the emperor, instead of exerting his right of appeal to
synods, is to lose all right of appeal and never to be restored or
pardoned. If a provincial synod be divided as to the guilt of a bishop,
the metropolitan is to convene bishops from the neighbouring provinces
to decide the cause jointly with the bishops of the original province.

A few years later, in 347, the council of Sardica, a council of
practically the whole West save Africa, reversed Tyre and acquitted St
Athanasius after a full judicial inquiry. This council endeavoured to
set up a system of appeals in the case of bishops, in which the see of
Rome was made to play a great part. "Out of honour to the memory of St
Peter," a condemned bishop may ask the intervention of Rome. If this be
done, the synod of first instance is to send letters to Julius, bishop
of Rome. If that prelate think the cause should be heard again, he is to
appoint judges; if otherwise, the original judgment is to be confirmed.
Pending appeal, the appellant's see is not to be filled up. The judges
appointed by the bishop of Rome to hear the appeal are to be from the
neighbouring provinces. The appellant may, however, request that bishop
to send priests from his side to sit with the synod of appeal. If such
priests are sent, they are to preside in the court of appeal. These
canons were always repudiated in the East, and when, sixty years
afterwards, they were, for the first time, heard of in Africa, they were
repudiated there also.

A rescript of Gratian in 378 empowered the bishop of Rome to judge
bishops with the assistance of six or seven other bishops or, in the
case of a metropolitan, of fifteen comprovincial bishops. A bishop
refusing to come to Rome was to be brought there by the civil power. The
rescript, however, was not incorporated in the Codes and perhaps was
only a temporary measure.

The tendency to give pre-eminence to Rome appears again in an imperial
letter to St Flavian, who, in the judgment of the East, was bishop of
Antioch, but who was rejected by the West and Egypt, summoning him to
Rome to be there judged by the bishops of the imperial city--a summons
which St Flavian did not obey (Tillemont, _Mém. Ecc._). In Africa in the
beginning of the 5th century Apiarius, a priest who had been deposed by
the bishop of Sicca for immorality, and whose deposition had been
affirmed by the "provincial synod," instead of further appealing to a
general synod of Africa, carried his appeal to Pope Zosimus. The pope
received the appeal, absolved him and restored him to the rank of
priest, and sent a bishop and two priests as legates to Africa with
instructions to them to hear the cause of Apiarius anew and for
execution of their sentence to crave the prefect's aid; moreover, they
were to summon the bishop of Sicca to Rome and to excommunicate him,
unless he should amend those things which the legates deemed wrong. The
upshot of a long conflict was that the papal claim to entertain appeals
from Africa by priests and deacons was rejected by the African bishops,
who in their final synodical epistle also repudiate in terms any right
of appeal by African _bishops_ to "parts beyond the seas" (see Hefele,
_Councils_, bk. viii.).

The story of the administrative development of the Church in the 5th
century is mainly the story of the final emergence and constitution of
the great "patriarchates," as authorities superior to metropolitans and
provincial synods. In consequence of the occupants of the thrones of
Constantinople and Alexandria falling successively into opposite
heresies, the question arose how "patriarchs" were to be judged. In both
cases, as it seems, an attempt was made by the bishop of Rome to depose
the erring patriarch by his authority as primate of Christendom, acting
in concert with a Western synod. In both cases, apparently, an
oecumenical synod ignored the Roman deposition and judged the alleged
offences of the respective patriarchs in first and last instance. The
third and fourth oecumenical synods (Ephesus, 431; Chalcedon, 451) were
primarily tribunals for the trials of Nestorius and Dioscorus; it was
secondarily that they became organs of the universal episcopate for the
definition of the faith, or legislative assemblies for the enactment of
canons. Nothing is more remarkable than their minute care as to
observance of rules of procedure. In both cases, imperial assessors were
appointed. At Ephesus the Count Candidian was commissioned to maintain
order, but took little part in the proceedings. At Chalcedon, on the
other hand, the imperial commissioners decided points of order, kept the
synod to the question, took the votes and adjourned the court. But the
synod alone judged and pronounced sentence. No oecumenical synod has
tried a patriarch of Old Rome while yet in the flesh. The fifth
oecumenical council came nearest to so doing, in the case of Vigilius.
That pope, although in Constantinople, refused to attend the sittings of
the council. He was cited three times, in the canonical manner, and upon
not appearing was threatened in the third session with anathema (Hefele,
_Councils_, sect. 268 _ad fin._). He was not, however, charged with
direct heresy, as were Nestorius and Dioscorus, and the synod seems to
have hesitated to deal stringently with the primate of Christendom. In
the seventh session it accepted the suggestion of Justinian, merely to
order the name of Vigilius to be removed from the liturgical prayers, at
the same time expressing its desire to maintain unity with the see of
Old Rome (Hefele, sect. 273). After the council, Justinian banished the
pope to Egypt, and afterwards to an island, until he accepted the
council, which he ultimately did (ib. 276). The sixth oecumenical synod
decreed that the dead pope Honorius should be "cast out from the holy
Catholic Church of God" and anathematized, a sentence approved by the
reigning pope Leo II. and affirmed by the seventh oecumenical synod in
787.

The constitution of the patriarchal system resulted in the recognition
of a certain right of appeal to Rome from the larger part of the West.
Britain remained outside that jurisdiction, the Celtic churches of the
British islands, after those islands were abandoned by the Empire,
pursuing a course of their own. In the East, Constantinople, from its
principality, acquired special administrative pre-eminence, naturally
followed, as in the case of "old Rome," by judicial pre-eminence. An
example of this is found in the ninth canon of Chalcedon, which also
illustrates the enforcement upon a clerical plaintiff in dispute with a
brother cleric of that recourse to the arbitration of their
ecclesiastical superior already mentioned. The canon provides that any
clerk having a complaint against another clerk must not pass by his own
bishop and turn to secular tribunals, but first lay bare his cause
before him, so that by the sentence of the bishop himself the dispute
may be settled by arbitrators acceptable to both parties. Any one acting
against these provisions shall be subject to canonical penalties. If any
clerk have a complaint against his own bishop, he shall have his cause
adjudicated upon by the synod of the province. But if a bishop or clerk
have a difference with the metropolitan of his province let him bring it
before the exarch of the "diocese" (i.e. the larger district answering
to the civil "diocese"), or before the royal see of Constantinople, who
shall do justice upon it. An "exarch" means properly a superior
metropolitan having several provinces under him. In the next century
Justinian (_Nov._ 123, c. 22) put the other patriarchates on the same
footing as Constantinople. In c. 21 he gives either plaintiff or
defendant an appeal within ten days to the secular judge of the locality
from the bishop's judgment. If there be no appeal, that judge is to give
execution to the episcopal award. The growth of a special "original"
jurisdiction at Constantinople, which perhaps developed earlier than
the corresponding institution at Rome, may be traced to the fact that
bishops from all parts were constantly in Constantinople. The bishop of
Constantinople, even before he became properly "patriarch," would often
assemble a synod from these visiting bishops, which acquired the
technical name of [Greek: synodos endêmousa], the synod of sojourners.
This synod frequently decided questions belonging to other
patriarchates.

The criminal jurisdiction thus exercised was generally speaking
unlimited. It must be remembered that the _forum externum_ of the
ecclesiastical jurisdiction, in the sense in which we now use the
phrase, of a judge deciding causes, was not then clearly marked off from
the _forum internum_, or what afterwards came to be called the "tribunal
of penance" (see Van Espen, _Jus ecc. univ._ pars iii. tit. iv. c. 1).
Ecclesiastical proceedings by way of prosecution are called "criminal,"
but they are primarily _pro salute animae_; whereas temporal criminal
proceedings are primarily for the protection of the state and its
citizens. Hence a Christian might be first punished in the civil courts
and then put to public penance by the ecclesiastical jurisdiction, or
vice versa: an apparently double system of punishment which the medieval
Church, when the _forum externum_ had become quite separated from the
_forum internum_, sometimes repudiated (see Maitland, _English Canon
Law_, 138, 139, 144).

Theodosius began the system of giving secular authority to Church
tribunals. Thus, in 376, L. 23 _Cod. Theodos. de. Episcopis_, &c.,
subjected clerics for small offences pertaining to the observances of
religion to bishops and synods. In 399, L. 1 _Cod. de Religione_
provides that, when it is a matter of religion, it beseems the bishop to
judge. A rescript of Constantius, in 355, inserted in _Cod. Theod._
lxii. _de Epis. Ecc. et Cler._, excluded bishops from accusations before
secular judges and commanded such accusations to be speedily brought
before the tribunal of other bishops. This law was probably only
intended to be of a temporary character. Then comes the law of Gratian
already noticed. Then, in 399, a law of Honorius (_Cod. Theod._ L. 1 _de
Religione_): "As often as it concerns religion, it is meet that the
bishops should judge, but other causes which belong to ordinary
jurisdiction or to public law are to be heard in the ordinary courts
(_legibus oportet audiri_)." L. 3 _de Epis. Jud._, at the end of the
Theodosian Code, seems spurious (see the comment of Gothofredus in
loco). But a constitution of Honorius in 412 (_Cod. Theod._ L. xli. _de
Epis. Ecc. et Cler._) provides that clerks are not to be accused except
before the bishop. Bishops, priests, deacons, and every other "minister
of the Christian law" of inferior degree, are taken from secular
jurisdiction in criminal cases. The words are quite general; but it has
been contended that they apply only to crimes of an ecclesiastical
character (see Gothofredus in loc.; Van Espen, pars iii. tit. iii. c. 1,
10). In 425 a constitution of Theodosius II. provides that a recent
decree of the usurper John should be disregarded and that clerks whom he
had brought before secular judges should be reserved for the episcopal
jurisdictions, "since it is not lawful to subject the ministers of the
divine office to the arbitrament of temporal powers." Justinian has a
clearer perception of the demarcation between the spheres of spiritual
and temporal law. The 83rd Novell provides that if the offence be
ecclesiastical, needing ecclesiastical correction, the bishop shall take
cognizance of it. The 123rd Novell (c. 21) provides that if a clerk be
accused of a secular crime he shall be accused before his bishop, who
may depose him from his office and order, and then the competent judge
may take him and deal with him according to the laws. If the prosecutor
have first brought him before the civil judge, the evidence is to be
sent to the bishop, and the latter, if he thinks the crime has been
committed, may deprive him of his office and order, and the judge shall
apply to him the proper legal punishment. But if the bishop think the
evidence insufficient, the affair shall be referred to the emperor, by
way of appeal both from bishop and judge. If the cause be
ecclesiastical, the civil judges are to take no part in the inquiry. The
law includes with clerics, monks, deaconesses, nuns, ascetics; and the
word "clerics" covered persons in minor orders, down to doorkeepers. It
will be noticed that Justinian supposes that the prosecutor may begin
the proceedings before the civil judge. A constitution of Alexius
Comnenus I. seems to send him to the special forum of the accused.


  Anglo-Saxon courts.

Certain enactments of later Saxon times in England have been sometimes
spoken of as though they united together the temporal and spiritual
jurisdictions into one mixed tribunal deriving its authority from the
State. In the latter part of the 10th century, laws of Edgar provided
that the bishop should be at the county court and also the alderman, and
that there each of them should put in use both God's laws and the
world's law (Johnson's _English Canons_, i. 411). This probably was, as
Johnson suggests, that the bishop might enforce secular laws by
ecclesiastical censure and the alderman ecclesiastical laws with secular
punishment. But the two jurisdictions were kept separate; for by another
law of Edgar (_Leges Edg._ c. v.) it was provided that "in the most
august assembly the bishop and alderman should be present, and the one
should interpret to the people the law of God, the other the laws of
men." Edgar, in a speech to St Dunstan and the bishops in synod (in
969), said, "I hold in my hands the sword of Constantine, you that of
Peter. Let us join right hands and unite sword to sword" (Hardouin,
_Conc._ tom. vi. p. 1, col. 675). The juxtaposition of the judicatures
may, however, have led to some confusion between them.

As to appeals the mixed council of Cliff at Hoo (747) said they should
go to the synod of the province. The only appeal to Rome in Saxon times
was that of St Wilfrid, bishop of York, who appealed from the division
of his see and his deposition for refusing to consent to it, and was
heard in a Roman synod under the presidency of Pope Agatho. The synod
found him unlawfully deposed and ordered his restoration. Upon his
return to England, the Roman judgment was refused recognition and he was
for a time imprisoned. Ten years later he was recalled to York, but
refusing to consent to the division of his see was again deposed and
again appealed to Rome. The appeal was heard at great length, in a synod
of 703 under John VI., deputies from the archbishop of Canterbury being
present. St Wilfrid was justified and was sent back to his see, with
papal letters to the kings of Northumbria and Mercia. The Roman decree
was again disregarded. At the council of "Nid" he was reconciled to the
other bishops of the province, but not restored. In the end he was
brought back to York, but not to the undivided see. The details of the
case will be found in Wilkins, _Concilia_, in Mansi, _Concilia_, under
the various councils named, and in Haddan & Stubbs, _Councils and Eccl.
Documents_, vol. iii.


  Penalties inflicted by ecclesiastical courts.

The penalties which the spiritual court could inflict, in the period
between the edict of Milan and c. 854, were properly excommunication
whether generally or as exclusion from the sacraments for a term of
months or years or till the day of death and (in the case of clerics)
suspension or deposition. Gradually, however, doubtless by way of
commutation of excommunication and of penance, temporal penalties were
added, as scourging, banishment, seclusion in a monastery, fines. It is
difficult to say how far some of these temporal penalties were
penitential only or how far they could be inflicted _in invitos_. But
the secular arm, from the time of Nicaea I., was in the habit of aiding
spiritual decrees, as by banishing deposed bishops, and gradually by
other ways, even with laymen. Scourging (although it had been a
well-known punishment of the synagogue) was at first forbidden. Can. 28
(26) of the Apostolic Canons imposes deposition on any bishop, priest or
deacon striking the delinquent faithful. In Africa, however, a contrary
practice early sprang up (see St Augustine, _Epist._ clix. _ad Marcellum
al._ cxxxiii.). The small council of Vannes in Brittany in 465 made it
an alternative punishment for clerks convicted of drunkenness (Can. 13).
Canon 13 of the first council of Orleans, which has been cited in this
matter, seems to have no application. St Gregory the Great seems to
assume that scourging and seclusion in a monastery are in the discretion
of episcopal tribunals (see _Epistles_, lib. ii. ep. 11, 40, 42, 44, 45;
lib. vii. ep. 11, 67; lib. xii. ep. 31, c. 4). The 16th council of
Toledo (in 693) has been cited as if it visited certain very great
sinners with scourging as an ecclesiastical punishment. In fact, it only
approves the punishment as ordered by the Visigothic laws. An alleged
decree of a council of Autun in 670 is part of a code of discipline for
monasteries (see authorities cited by Hefele, _Councils_, sect. 290,
towards the end). Banishment does not seem to have been inflicted by the
spiritual court _in invitum_. Seclusion in a monastery seems first to
have been used by the civil power in aid of the spiritual. The fifth
canon of the council of Macon, in 584, forbids clergy to dress like
laymen and imposes a penalty of thirty days' imprisonment on bread and
water; but this may be merely penitential. There is little evidence of
the imposition of fines as ecclesiastical penalties; but there are
references to the practice in the epistles of St Gregory the Great,
notably in his instructions to St Augustine. Gregory III. copies from St
Gregory I. Probably these also were by way of penance. Isolated examples
in the early middle ages of metropolitans dealing with their suffragan
bishops by imprisonment in chains were extra-canonical abuses, connected
with the perversion of Church law which treated the metropolitan (who
originally was merely convener of the provincial synod and its
representative during the intervals of sessions) as the feudal "lord" of
his comprovincials.

With the later 9th century we enter upon a new epoch, and by the time of
Gregory VII., in the 11th century, the tribunals have fallen into the
hands of a regular class of canonists who are in fact professional
church-lawyers in orders. The changes due to the adoption of the False
Decretals by Nicholas I. and the application of their principles by
Hildebrand (afterwards Gregory VII.) are discussed in the article CANON
LAW. The later medieval system, thus inaugurated, may be considered (1)
in its hierarchy, (2) in the subject matter of its jurisdiction, (3) in
its penalties.


  Later medieval system.

1. (a) It is a system of courts. Much that had been done by bishops,
_sine strepitu forensi et figura judicii_, is now done in the course of
regular judicial procedure. Again, the court takes the place of the
synod. The diocesan synod ceases to have judicial work. The court of the
metropolitan takes the place of the provincial synod, except possibly
for the trial of bishops, and even this becomes doubtful.

(b) At first the bishop was the only judge in the diocesan court and he
always remains a judge. But just as the king appoints judges to hear
_placita coram rege ipso_, and the feudal lord appoints his seneschal or
steward, so the bishop appoints his official.

(c) The archdeacon acquires a concurrent ordinary jurisdiction with the
bishop (see ARCHDEACON). For some time it was considered that he was a
mere office-holder dependent on the will of the bishop with a
jurisdiction merely "vicarial"; but by the 13th century it was settled
that he held a "benefice" and that his jurisdiction over causes was
ordinary and independent of the bishop (Van Espen, pars i. tit. xii. c.
1; Fournier, _Les Officialités au moyen âge_, p. 134). It was partly in
order to counterpoise the power of archdeacons that bishops created
officials (Fournier, p. 8). Archdeacons in course of time created
officials who presided in court in their stead. The extent of
jurisdiction of archdeacons depended much upon local customs. In England
the custom was generally in their favour. Ordinarily, the appeal from an
archdeacon or his official lay to the court of the bishop; but by custom
the appeal might be to the court of the metropolitan: The Constitutions
of Clarendon, in 1164, made the appeal from the court of the archdeacon
lie to the court of the bishop.

(d) The official of the bishop might be his official principal, who was
his _alter ego_, or a special officer for a particular locality
(_officialis foraneus_). The latter was treated as a mere delegate, from
whom an appeal could be made to the bishop. The former had one
consistory with the bishop, so that appeals from him had to be made to
the court of the metropolitan. How far the official principal had
jurisdiction in criminal matters by virtue of his office, how far it was
usual to add this jurisdiction by special commission, and what were the
respective limits of his office and that of the vicar-general, are
questions of some nicety. The emphasis in Italy was on the vicar-general
(_Sext. de officio Vicarii_). In the Low Countries, France and England
the jurisdiction of the official principal was wider (Van Espen, pars
i. tit. xii. cc. 4, 5; Fournier, p. 21). But he could not try criminal
matters unless specially committed to him (Lyndwood, _Provinciale_, lib.
ii. tit. 1). Later in England it became usual to appoint one man to the
two offices and to call him chancellor, a word perhaps borrowed from
cathedral chapters, and not in use for a diocesan officer till the time
of Henry VIII. or later (see CHANCELLOR). In Ireland the title, till the
church was disestablished, was vicar-general.

The importance of distinguishing the normal functions of an official
principal and a vicar-general lies in this: that it was gradually
established that as a king should not hear causes but commit them to his
judges, so a bishop should not hear causes but appoint an official to
hear them (see Ridley, _View of the Civil and Eccl. Law_; Ayliffe,
_Parergon juris ecclesiastici_, p. 161; Godolphin, _Abridgement of the
Laws Ecclesiastical_, p. 8). The "parlements" of France were constantly
insisting on the independence and irremovability of the official
(Fournier, p. 219). But jurisdiction which was not necessarily incident
to the office of the official principal, that is to say voluntary
jurisdiction, such as the granting of licences and institution to
benefices, and criminal jurisdiction over clerks (and probably over
laymen), the bishop could reserve to himself. Reservations of this
nature are made in many English patents of chancellors and were held
good in _R._ v. _Tristram_, 1902, 1 K.B. 816.

(e) The ecclesiastical and temporal courts are kept distinct. The
charter of William the Conqueror abrogated the laws of Edgar. No bishop
or archdeacon "shall any longer hold pleas in the Hundred concerning
episcopal law nor draw a cause which concerns the rule of such to the
judgment of men of the world" (Stubbs, _Select Charters_, part iii.). In
France, where the bishop was a temporal baron, his feudal and his
spiritual courts were kept by distinct officers (Fournier, p. 2).

(f) From the bishop, or his official, appeal lay to the metropolitan,
who again could hear causes by his official. The Constitutions of
Clarendon recognize this appeal (c. viii.).

(g) An appeal lay from the court of the metropolitan to that of the
primate. There were many disputes as to the existence of these primates
(see Maitland, _Canon Law in the Church of England_, p. 121). In England
the dispute between Canterbury and York was settled by making them both
primates, giving Canterbury the further honour of being primate of all
England. In France the primatial sees and the course of appeals to them
were well established (Fournier, p. 219).

(h) Several attempts were made by metropolitans and their officials to
take causes arising in the dioceses of their comprovincials in the first
instance and not by way of appeal. The officials of primates in their
turn made similar attempts. After long struggles this was hindered, in
France by the bull _Romana_ (Fournier, p. 218), in England by the Bill
of Citations, 23 Henry VIII. c. 9, and Canon 94 of the Canons of 1603.
The preamble of the "Bill of Citations" is eloquent as to the mischief
which it is framed to prevent. There are, however, a few cases in which
the metropolitan is still allowed to cite in the first instance. One of
them was in cases of "perplexity." "Perplexity" arose where the
suffragans "could not owing to the geographical limitations of their
competence do full justice" (Maitland, pp. 118-119). Such was the case
of probate where notable goods of the deceased lay in more than one
diocese. Hence the origin of the "prerogative court" of Canterbury (cf.
Van Espen, pars i. tit. xix.; and for Spain, Covarruvias, _Pract.
Quaest._ c. 9).

(i) Gradually there grew up a mass of peculiar and exempt jurisdictions
(Ayliffe, pp. 417, 418; Phillimore, Eccl. Law, pp. 214, 927; de
Maillane, _Dict. du droit canonique_, s.v. "Exemptions"). Exempt
jurisdictions began with the monasteries and were matter of vehement
discussion in the later middle ages. There were no true exemptions
before the 11th century (Van Espen, pars iii. tit. xii.). Peculiar or
special jurisdiction, equal to that of the bishop, was given to deans
and chapters over the cathedral precincts and in places where they had
corporate property (see _Parham_ v. _Templer_, 3 Phil. Ecc. R. 22).
Sometimes it was given to deans alone or to prebendaries in the parishes
whence they derived their prebends. Where the archdeacon had a
jurisdiction co-ordinate with the bishop, it was called a peculiar. The
metropolitans had peculiars within the dioceses of their comprovincials
wherever they had residences or manors, and some whose origin is
uncertain, e.g. that of the fifteen parishes in the deanery of the
Arches. The official administering justice for the metropolitan was
usually called a dean. From a peculiar jurisdiction ranking as episcopal
the appeal lay to the court of the metropolitan. As to metropolitan
peculiars, the metropolitan might give an appeal from the dean to his
regular official principal. Thus, in Canterbury there was an appeal from
the dean of Arches to the official principal of the Arches court. When
peculiars were abolished (_vide infra_) the dean of Arches disappeared,
and his title, in the 19th century, was erroneously given to the
official principal. On peculiars in Spain cf. Covarruvias, _Works_, tit.
i. p. 410. The French parlements, after the middle ages, discouraged
them. In exempt convents the head of the monastery or priory exercised
jurisdiction subject to an appeal to the pope.

(j) It is said that originally a metropolitan had only one official
principal, who, like the metropolitan himself, acted both for the
diocese and province. Fournier (p. 219) says that in France it was not
till the 17th century that there grew up a custom of having different
officials for the metropolitan, one for him as bishop, a second as
metropolitan, and even a third as primate, with an appeal from one to
the other, and that it was an abuse due to the parlements which strove
to make the official independent of the bishop. In England there has
been, for a long time, a separate diocesan court of Canterbury held
before the "commissary." The word is significant as showing that there
was something special and restricted about the position. In York there
are two courts, one called the consistory for the diocese, the other
called the chancery for the province. But the same person was often
official of both courts.

(k) In England the Constitutions of Clarendon added a provision for
appeal to the king, "and if the archbishop shall have failed in doing
justice recourse is to be had in the last resort (_postremo_) to our
lord the king, that by his writ the controversy may be ended in the
court of the archbishop; because there must be no further process
without the assent of our lord the king." The last words were an attempt
to limit further appeal to Rome. It will be observed that the king does
not hear the cause or adjudicate upon it. He merely corrects slackness
or lack of doing justice (_Si archiepiscopus defecerit in justitia
exhibenda_) and by his writ (_precepto_) directs the controversy to be
determined in the metropolitan's court. As bishop Stubbs says (_Report
of Eccl. Comm._ vol. i. _Hist. App._ i.): "The appeal to the king is
merely a provision for a rehearing before the archbishop, such failure
to do justice being not so much applicable to an unfair decision as to
the delays or refusal to proceed common at that time" (cf. Joyce, _The
Sword and the Keys_, 2nd ed. pp. 19-20). The _recursus ad principem_, in
some form or other of appeal or application to the sovereign or his lay
judges, was at the end of the middle ages well known over western
Europe. This recourse in England sometimes took the form of the appeal
to the king given by the Constitutions of Clarendon, just mentioned, and
later by the acts of Henry VIII.; sometimes that of suing for writs of
_prohibition_ or _mandamus_, which were granted by the king's judges,
either to restrain excess of jurisdiction, or to compel the spiritual
judge to exercise jurisdiction in cases where it seemed to the temporal
court that he was failing in his duty. The _appellatio tanquam ab abusu_
(_appel comme d'abus_) in France was an application of a like nature.
Such an appeal lay even in cases where there was a refusal to exercise
voluntary jurisdiction (de Maillane, _Dictionnaire du droit canonique_,
tit. "Abus," cf. tit. "Appel"). This writer traces their origin to the
14th century; but the procedure does not seem to have become regularized
or common till the reigns of Louis XII. or Francis I. (cf. _Dict.
eccl._, Paris, 1765, titt. "Abus" and "Appel comme d'abus"). On the
_recursus ad principem_ and the practice of "cassation" in Belgium,
Germany and Spain, cf. Van Espen's treatise under this title (_Works_,
vol. iv.) and _Jus eccles. univ._ pars iii. tit. x. c. 4. Louis XIV.
forbad the parlements to give judgment themselves in causes upon an
_appel comme d'abus_. They had to declare the proceedings null and
abusive and command the court Christian to render right judgment (Edict
of 1695, arts. 34, 36, cited in Gaudry, _Traité de la législation des
cultes_, Paris, 1854, tom. i. pp. 368, 369).

In Catalonia "Pragmatics," letters from the prince, issued to restrain
jurisdiction assumed by ecclesiastical judges contrary to the customs of
the principality. Thus in 1368 Peter III. evoked to the royal court a
prosecution for abduction pending before the archbishop of Tarragona,
declaring that the archbishop and the official were incompetent to judge
noblemen. See this and other instances collected in _Usages y demas
derechos de Cataluña_, by Vives y Cebriá (Barcelona, 1835), tom. iv. p.
137 et seq.

(l) Lastly there was the appeal to the patriarchs, i.e. in the West to
Rome. The distinguishing feature of this appeal was that the rule of the
other appeals did not apply to it. In the regular course of those
appeals an appellant could not leap the intermediate stages; but he
could at any stage go to this final appeal, _omisso medio_, as it was
technically called (see _de appell. c. Dilect._ iii. for general rule,
and c. 3 _de appell._ in 6 for different rule in case of the pope, and
authorities cited in Van Espen, pars iii, tit. x. c. 2, 5). Van Espen
says: "The whole right of appeal to the Roman pontiff _omisso medio_ had
undoubtedly its origin in this principle, that the Roman pontiff is
ordinary of ordinaries, or, in other words, has immediate episcopal
authority in all particular churches, and this principle had its own
beginning from the False Decretals."

Appeals to Rome lay from interlocutory as well as final judgments.
Causes could even be evoked to Rome before any judgment and there heard
in first instance (Van Espen, pars iii. tit. x. c. 1, 8).

There was an alleged original jurisdiction of the pope, which he
exercised sometimes by permanent legates, whom Gregory VII. and his
successors established in the chief countries of Europe, and to whom
were committed the legislative executive and judicial powers of the
spiritual "prince" in the districts assigned to them. These Clement IV.
likened to "pro-consuls" and declared to have "ordinary" jurisdiction;
because they had jurisdiction over every kind of cause, without any
special delegation, in a certain defined area or province (c. ii. _de
Officio Legati_ in 6). They were expressed to have not merely appellate
but original jurisdiction over causes (iii. c. i. _de Officio Legati_).
The occupants of certain sees by a kind of prescription became legates
without special appointment, _legati nati_, as in the case of
Canterbury. In the 13th century Archbishop Peckham, says Maitland (p.
117), as archbishop "asserted for himself and his official (1) a general
right to entertain in the first instance complaints made against his
suffragans' subjects, and (2) a general right to hear appeals _omisso
medio_." It was, for the time, determined that the archbishop might
himself, in virtue of his legatine authority, entertain complaints from
other dioceses in first instance, but that this legatine jurisdiction
was not included in the ordinary jurisdiction of his official principal,
even if the archbishop had so willed it in his commission. In fact,
however, the official did before the end of the later medieval period
get the same power as the archbishop (Maitland, pp. 118-120; cf.
Lyndwood, lib. v. tit. 1), till it was taken from him by the Bill of
Citations.

After legates came special delegates appointed by the pope to hear a
particular cause. It was the general practice to appoint two or three to
sit together (Van Espen, pars iii. tit. v. c. 2, 37). These might
sub-delegate the whole cause or any part of it as they pleased, ibid.
9-18. Dr Maitland (essay on "The Universal Ordinary") thinks, but
without very much foundation, that great numbers especially of the more
important causes were tried before these delegates; although the records
have largely perished, since they were the records of courts which were
dissolved as soon as their single cause had been decided. These courts
were convenient, since it was the custom to appoint delegates resident
in the neighbourhood, and the power of sub-delegation, general or
limited, simplified questions of distance. In Belgium causes appealed
to Rome had to be committed to local delegates (Van Espen, pars iii.
tit. v. c. 3, tit. x. c. 2).

There could be an appeal from these delegates to the pope and from the
pope himself to the pope "better informed" (Van Espen, pars iii. tit. x.
c. 2, 12, 13). So personal had the system of jurisdiction become that
even the trials of bishops ceased to be necessarily conciliar. Generally
they were reserved to the pope (Van Espen, pars iii. tit. iii. c. 5,
17-19); but in England the archbishop, either in synod, or with some of
his comprovincial bishops concurring, tried and deposed bishops (see
case of Bishop Peacock and the other cases cited in _Read_ v. _Bishop of
Lincoln_, 14 P.D. 148, and Phillimore, _Eccl. Law_, pp. 66 et seq.).

(m) The jurisdiction of a bishop _sede vacante_ passed, by general law,
to the dean and chapter; but in England the metropolitans became
"guardians" of the spiritualities and exercised original jurisdiction
through the vacant diocese (Phillimore, pp. 62-63), except in the case
of Durham, and with a peculiar arrangement as to Lincoln.

If the metropolitan see were vacant the jurisdiction was exercised by
the dean and chapter through an official (Rothery, _Return of Cases
before Delegates_, Nos. 4, 5). As to France see Fournier, p. 294.

(n) Officials, even of bishops and metropolitans, need not be in holy
orders, though Bishop Stubbs in his paper in the _Report of the
Commission on Ecclesiastical Courts_ seems to say so. They had to be
clerics, that is, to have received the tonsure. Even papal delegates
might be simple clerks (Van Espen, pars iii. tit. v. c. 2, 20).

It came, however, to be the practice to impose some restrictions, as on
clerks twice married. Thus Archbishop Chichele provided that no clerk
married or bigamous (that is, having had two wives in succession) should
exercise spiritual jurisdiction (see Lyndwood, lib. iii. tit. 3). Abroad
unsuccessful attempts were made by local councils to enact that
officials and vicars-general should be in holy orders (Hefele on
Councils of Tortosa in 1429 and Sixth of Milan in 1582). These councils,
as will be seen, are late.

(o) With or without the concurrence and goodwill of the national Church,
restrictions were imposed by the State on the papal jurisdiction,
whether original or appellate. In England the Constitutions of Clarendon
(by chap. viii.) prohibited appeals to the pope; but after the murder of
St Thomas of Canterbury Henry II. had to promise not to enforce them.
The statutes 38 Edw. III. st. 2, 13 Rich. II. st. 2, c. 2, and 16 Rich.
II. c. 5 forbid such appeals; but it is suggested that notwithstanding
the generality of their language they refer only to cases of temporal
cognizance. Cases upon the execution of these statutes are collected in
Stillingfleet, _On Ecclesiastical Jurisdiction_, p. 189; Gibson,
_Codex_, 83. Obstacles were placed in the way of appeals to the pope
_omisso medio_. Thus when a writ of _significavit_ issued on the mandate
of a bishop, an appeal to Rome availed not to stay execution; but if
there were an appeal to the archbishop it was otherwise. It therefore
became the custom to lodge a double appeal: one to the archbishop "for
defence," and the other to the pope as the real appeal ("Hostiensis,"
_Super Decret._ ii. fol. 169; cf. Owen, _Institutes of Canon Law_, 1884,
pt. i. c. 19, 5).

There seems to have been no machinery for assisting the original or
appellate jurisdiction of the pope by secular process,--by
_significavit_ or otherwise.

The matrimonial cause between Henry VIII. and Catharine of Aragon was
the most famous English cause tried by delegates under the "original"
jurisdiction of the pope, and was ultimately "evoked" to Rome. The
foreseen adverse termination of this long-drawn cause led to Henry's
legislation.

When the temporal courts interfered to prevent excess of jurisdiction,
they did so by prohibiting the ecclesiastical court from trying and the
suitor from suing in that court. The pope could not be effectively
prohibited, and no instance is recorded of a prohibition to papal
delegates. But suitors have been prohibited from appealing to the pope
(see per Willes, J., in _Mayor of London_ v. _Cox_, L.R. 2 H.L. 280).
Whatever may have been the law, it is certain that, notwithstanding the
statutes of Edw. III. and Rich. II., appeals to Rome and original trials
by papal delegates did go on, perhaps with the king's licence; for the
statute 24 Hen. VIII. c. 12 recites that the hearing of appeals was an
usurpation by the pope and a grievous abuse, and proceeds to take away
the appeal in matrimonial, testamentary and tithe causes, and to hinder
by forbidding citation and process from Rome, all original hearings
also. The statute 25 Hen. VIII. c. 19 follows this up by taking away
appeals in all other subjects of ecclesiastical jurisdiction.

In 1438 the council of Basel took away all papal original jurisdiction
(save in certain reserved cases--of which _infra_), evocation of causes
to Rome, appeals to Rome _omisso medio_, and appeals to Rome altogether
in many causes. Such appeals when permissible, except the "greater,"
were to be tried by delegates on the spot (31st Session; Mansi,
_Concilia, in loco_). These proceedings at Basel were regarded at Rome
as of no effect. Nevertheless this decree and others were adopted by a
French national council at Bourges and promulgated by the king as a
"Pragmatic Sanction" (Migne, _Dict. du droit canonique_, "Pragmatique
Sanction"). The parlements registered the Sanction and the effect was
permanent in France. Louis XI. and Charles VIII. sought to revoke it;
but both parlements and states-general refused to recognize the revoking
decrees. In 1499 Louis XII. ordered the Pragmatic to be inviolably
observed. The parlements thereupon condemned several private persons for
obtaining bulls from Rome. In 1516 a Concordat between Leo X. and
Francis I. settled all these questions in the sense of the Pragmatic,
substantially according to the Basel canon. All causes, except the
"greater," were to be terminated in the country where the proper
cognizance would lie (Migne, op. cit. "Concordat"). By this Concordat,
by an ordinance of Francis I. in 1539, by two or three other royal
edicts, and (above all) by the practice of the parlements, explanatory
of this legislation, and their _arrêts_, the conflict of secular and
ecclesiastical jurisdictions was settled until the Revolution (Migne,
_ubi sup._). "Greater causes" came in France to be restricted to
criminal prosecutions of bishops. Even in these the original
jurisdiction of the pope was taken away. In first instance they were
tried by the provincial synod. Thence there was appeal to the pope (de
Maillane, op. cit. s.v. "Causes majeures"; _Dict. eccl._, Paris, 1765,
s.v. "Cause"). The only original jurisdiction left to the pope was in
the case of the matrimonial causes of princes. But they could only be
heard on the spot by judges delegate. Examples are the causes of Louis
XII. and Jeanne of France in 1498, and of Henry IV. and Marguerite of
Valois in 1599 (Migne, op. cit. s.v. "Causes"). The prohibition of papal
interference was enforced if necessary by the _appel comme d'abus_
(_vide supra_). Out of respect for the pope this appeal was not brought
against his decrees but against their execution (_Dict. eccl._, Paris,
1765, s.v. "Abus").

Spain appears to have permitted and recognized appeals to the pope. A
royal writ of the 16th century cited by Covarruvias (c. xxxv.) prohibits
execution of the sentence of a Spanish court Christian pending an appeal
to the pope.


  Civil jurisdiction.

2. The subject matter over which the ecclesiastical courts had
jurisdiction was no longer purely "criminal" with a civil
quasi-jurisdiction by way of arbitration. In the later middle ages these
courts had jurisdiction over most questions, except indeed the then most
important ones, those relating to real property. This civil jurisdiction
was sometimes concurrent with that of the secular courts, sometimes
exclusive. For England it may be thus classified:--

(a) _Matrimonial._--This arose naturally from the sacred character of
Christian marriage. This jurisdiction was exclusive. From it followed
the right of the courts Christian to pronounce upon questions of
legitimacy. Upon this right an inroad was early made, in consequence of
the question of legitimation by subsequent marriage. In the 12th century
the Church's rule, that subsequent marriage did legitimize previous
issue, was settled (c. 6, x. 4, 17). The king's judges then began to ask
the ordinary the specific question whether A. B. was born before or
after his parents' marriage. After the inconclusive proceedings at the
realm-council of Merton (1236), when spiritual and temporal lords took
opposite views, the king's judges went a step further and thenceforward
submitted this particular question to a jury. All other questions of
legitimacy arising in the king's courts were still sent for trial to the
bishop and concluded by his certificate (see Pollock and Maitland,
_Hist. Eng. Law before Edward I._ vol. i. 105-106; Maitland, _ubi
supra_, pp. 53-56).

(b) _Testamentary and in regard to succession from intestates._--Real
property was not the subject of will or testament in the medieval
period. But as to personal property, the jurisdiction of the courts
Christian became exclusive in England. The Church, East and West, had
long asserted a right to supervise those legacies which were devoted to
pious uses, a right recognized by Justinian (_Cod._ i. 3. 46). The
bishop or, failing him, the metropolitan, was to see such legacies
properly paid and applied and might appoint persons to administer the
funds (Pollock and Maitland, op. cit. ii. 330). This right and duty
became a jurisdiction in all testamentary causes. Intestacy was regarded
with the greatest horror, because of the danger to the intestate's soul
from a death without a fitting part given to pious uses (Maine, _Ancient
Law_, ed. 1906, note by Pollock, p. 230; cf. Pollock and Maitland, op.
cit. ii. 354). Hence came the jurisdiction of the ordinary in intestacy,
for the peace of the soul of the departed. This head of ecclesiastical
jurisdiction was in England not transferred to the secular court till
1857.

(c) _Church Lands._--If undoubtedly held in _frankalmoign_ or "free
alms," by a "spiritual" tenure only, the claim of jurisdiction for the
ecclesiastical _forum_ seems to have been at first conceded. But the
Constitutions of Clarendon (c. 9) reserved the preliminary question, of
"frankalmoign" or not, for a jury in the king's court. Then, if the
tenure were found free alms, the plea was to be heard in the court
Christian. From the 13th century, however, inclusive, the king's courts
insisted on their exclusive jurisdiction in regard to all realty,
temporal or "spiritual" (Pollock and Maitland, op. cit. i. 106).

(d) _Title to present to and possession of benefices._--As to the title
to present to benefices, the courts Christian at one time had concurrent
jurisdiction with the temporal courts. "Advowsons" were, however, looked
upon as a species of "real" property in England, and therefore the
king's court early claimed exclusive jurisdiction in disputes where the
title to present was involved. The Constitutions of Clarendon provided
that these causes should be heard only in the king's court (c. 1). This
rule was applied even where both litigants were "spiritual." In the 13th
century abbots sue each other in the royal court for advowsons (Selden
Soc. _Select Civil Pleas_, i. pl. 245). In 1231, in such a suit, the
bishop of London accepts wager of battle (Pollock and Maitland, op. cit.
i. 105). In cases, however, where the title to present was not in
question, but the fitness of the clerk presented, or, in cases of
election to benefices, the validity of the election, there was
jurisdiction in the courts Christian.

(e) _The recovery of tithes and church dues,_ including in England
church rates levied to repair or improve churches and churchyards.

(f) Questions concerning _fabrics, ornaments, ritual and ceremonial_ of
churches.

(g) _Administration of pious gifts and revenues given to prelates or
convents._--Their right application could be effectively enforced only
in the courts Christian; until the rise in England of the equitable
jurisdiction of the court of chancery and the development of the
doctrine of "uses" at the end of the middle ages.

(h) _Enforcement of contractual promises made by oath or pledge of
faith._--The breaking of such a promissory oath was called "perjury" (as
in classical Latin and in Shakespeare), contrary to modern usage which
confines the word to false evidence before a court of justice. In regard
to the execution of these promises, the jurisdiction of the
ecclesiastical courts was possibly traversed by c. 15 of the
Constitutions of Clarendon; but allowed by the statute 13 Edw. I. st. 4.
As just intimated, besides the enforcement of the promise, the
"perjury" was treated as an ecclesiastical crime.

The _criminal jurisdiction of courts Christian over laymen_ included,
besides these "perjuries," (a) all _sexual offences_ not punishable on
indictment; (b) _Defamation of character_ (the king's courts came in
time to limit this to such defamation as could not be made the subject
of a temporal action); (c) _Offences by laymen against clerks_ (i.e.
against all "tonsured" persons, supra); (d) _Offences in regard to holy
places_--"brawling" and such like; (e) _Heresy, schism, apostasy,
witchcraft_.

In regard to "clerks," there was (1) all the criminal jurisdiction which
existed over laymen, and (2) criminal jurisdiction in regard to
professional misconduct. Concerning "felonious" clerks the great
questions discussed were whether the courts Christian had exclusive
jurisdiction or the king's court, or whether there was a concurrent
jurisdiction. The subject was dealt with in the Constitutions of
Clarendon, formally revoked after the murder of St Thomas of Canterbury.
In the 13th century it was recognized that a "clerk" for felony was
subject only to ecclesiastical trial and punishment; punishment which
might involve lifelong imprisonment. For "misdemeanours," as yet
unimportant, he had no exemption from secular jurisdiction (Pollock and
Maitland, op. cit. ch. iv.). At some indeterminate later period, the
"clerk" was tried for felony by a jury in the king's court and then
"pleaded his clergy," after conviction there, and was remitted to the
ordinary for ecclesiastical punishment. "Clerks" for the purpose of
"benefit of clergy" included not only persons in minor orders, but all
"religious" persons, i.e. monks, friars, nuns, &c. Later the custom
arose of taking "clerk" to include any "literate," even if not in orders
or "religious" (cf. Stephen, _Hist. Crim. Law_, i. 461). The statute 4
Hen. VII. c. 13 took away benefit of clergy, if claimed a second time,
from persons not "within orders," in certain bad cases. 4 Hen. VIII. c.
2 (a temporary act) took away "clergy," in certain heinous crimes, from
all persons not in "holy" orders. This statute was partly renewed by 22
Hen. VIII. c. 13. Other changes were introduced by 23 Hen. VIII. c. 1
and later acts. In time, "benefit of clergy" became entirely diverted
from its original objects.

In _France_, till 1329, there seems to have been no clear line of
demarcation between secular and ecclesiastical jurisdictions. Beaumanoir
(_Coutume de Baulvoisis_, ch. xi., cited Gaudry, op. cit. i. 22) had
laid down the principle that spiritual justice should meddle only with
spiritual things. In the year named the secular courts complained to the
king, Philip of Valois, of the encroachments of the courts Christian.
The "cause" was solemnly argued before that monarch, who decided to
leave things as they were (Migne, _Dict. du droit canon._, s.v.
"Officialités"). In 1371 Charles V. forbade spiritual courts to take
cognizance of "real" and "possessory" actions even in regard to clerks
(Migne, loc. cit.; cf. Gaudry, _ubi sup._). From this period the
parlements began the procedure which, after the Pragmatic Sanction of
Charles VII., in 1438 took regular shape as the _appel comme d' abus_
(_supra_; Migne, loc. cit.). Testamentary causes at first were subject
to the concurrent jurisdiction of the spiritual and secular courts.
After the 14th century, the latter had exclusive jurisdiction (Van
Espen, op. cit. lib. iii. tit. ii. cc. 2, 15, 16). In regard to
_marriage_ the secular jurists distinguished between the civil contract
and the sacrament, for purposes of separating the jurisdiction (_Dict.
eccl._, Paris, 1765, s.v. "Mariage"). The voluntary jurisdiction as
regards dispensations was kept for the Church. The contentious
jurisdiction of the courts Christian was confined to promises of
marriage, nullity of marriage caused by "diriment" impediments only,
validity or invalidity of the sacrament, divorce _a thoro_ (ibid.).
Questions in regard to the _property in a benefice_ were for the courts
Christian; in regard to its _possession_, for the king's courts. But if
a "possessory" action had been brought in the latter, a subsequent suit
in the courts spiritual for the property was deemed "abusive" and
restrained (ib., s.v. "Pétitoire") _Breach of faith or of promise
confirmed by oath_ was matter for the court Christian (Fournier, pp. 95,
99, 109, 125). This branch of jurisdiction was larger and more freely
used than in England (cf. Pollock and Maitland, op. cit., as to
Normandy). The only other remaining civil jurisdiction of the
ecclesiastical courts was in _personal actions where clerks were
defendants_ (Migne, op. cit., s.v. "Officialités," Fournier, pp.
65-125); or, after the 14th century, where both parties were clerks. In
regard to crimes delicts (_délits_) were divided into classes for
purposes of jurisdiction. Clerks were punishable only in the court
Christian, except in cases of grave crimes such as murder, mutilation
(Fournier, p. 72), and cases called "royal cases" (_vide infra_). Laymen
were punishable in the court Christian for the _délits_ following:
injury to sacred or religious places, sacrilege, heresy (except where it
was a "royal case"), sorcery, magic, blasphemy (also punishable in the
secular court), adultery, simony, usury and infractions of the truce of
God (Fournier, pp. 90-93). What were called "privileged delicts" were
judged in the case of the clergy conjointly by the spiritual judge and
the king's judge. Bishops had no exemption (_Dict. ecc._, s.v. "Délits,"
"Cas privilégié," "Causes majeures"). "Royal cases" included such crimes
as touched the prince, as all forms of treason; or the dignity of his
officers; or the public safety. In this class were also included such
heresies as troubled the state, as by forbidden assemblies, or by
teaching prohibited doctrine. Among these heresies were reckoned
idolatry, atheism, Protestantism, relapse (_ib. et_ "Cas royaux,"
"Hérésie"). These were of exclusive royal jurisdiction as against both
spiritual courts and the courts of feudal lords. A similar claim was
made by Pombal for Portugal (_vide infra_).

The parlements, in order to have a ready means of enforcing all these
restrictions by _appel comme d'abus_, compelled the bishops to appoint
officials, Frenchmen, graduates, and (as it seems) "seculars" (_Dict.
eccl._, Paris, 1765, s.v. "Official"). This last qualification was
disputed (see Fevret, _Traité de l'abus_).

3. _Punishments._--Ecclesiastical sanctions were divided into
_punishments_ (_poenae_), either purely temporal in character or else of
a mixed spiritual and temporal character, and _censures_ (_censurae_),
purely spiritual and remedial (see Van Espen, pars iii. tit. xl. cc. 1,
3; Phillimore, _Ecclesiastical Law_, p. 1064). In the book last cited
_censurae_ and _poenae_ are classed together as "censures" (which is the
modern use).

_Poenae._--(a) Fines sprang from the older custom of directing alms by
way of penance in the internal forum (Van Espen, _ubi sup._ c. 1, 5-10).
They were to be applied to pious uses. (b) _Reclusion in a monastery_
continued from former period, and might be either temporary or perpetual
(loc. cit. 17-19). (c) _Imprisonment_, in the bishop's prison, might be
in chains, or on bread and water, and temporary or perpetual. In its
severer forms it was only inflicted for more atrocious crimes which the
secular law would have punished with death (loc. cit. 21-27). The act 23
Henry VIII. c. 11 made special provision for convicted clerks who broke
out of the prisons of the ordinary. (d) _Fustigation_, as in former
period, was hardly an ecclesiastical punishment. If given, it was to be
of a paternal character (loc. cit. 39-45). Punishments of a mixed nature
were: (e) _Suspension_ either from office alone or from office and
benefice; (f) _Deprivation_ of benefice; (g) _Deposition_ or
_Degradation_ (a more solemn and ceremonial form) from the ministry; (h)
_Irregularity_--not always a punishment--a state of incapacity to be
ordained, or, being ordained, to execute the ministry; this might result
from some defect of mind and body, but was also incurred by some grave
offences.

_Censures_ were as follows: (i) _Suspension_ from attending divine
offices or _ab ingressu ecclesiae_, more appropriate for a layman. A
clerk in like case might be suspended from office. (j) _Interdict_ was
another form of partial or total suspension from the benefit of the
rites and sacraments of the Church. An interdict might be personal or
local (see INTERDICT). (k) _Excommunication_ was either greater or less.
The greater separated entirely from the Church. It might be pronounced
under anathema. The less deprived of participation in the sacraments,
and made a clerk incapable of taking a benefice.

On the European continent the courts Christian often carried out their
decrees by their own apparitors who could levy pecuniary penalties on a
defendant's goods (Van Espen, pars iii. tit. ix. c. 4). They could
arrest and imprison. In England, except in the peculiar case of
imprisonment pending trial for heresy, or in the case of a clerk
convicted of crime, these things could not be. The sentence of the court
Christian had in all other cases to be enforced by the secular arm.
Early in Henry II.'s time it had become the custom of England for the
court Christian to "signify" its sentence of excommunication to the king
and to demand from him a writ of _significavit_ to the sheriff, to
imprison the person excommunicated. The writ apparently issued for no
court inferior to the bishop's, unless upon the bishop's request. In
some sense the king's writ of _significavit_ was discretionary; but its
issue could be enforced by excommunication or interdict.

In the cases of heresy, apostasy and sorcery, the spiritual courts
sought the aid of the secular jurisdiction to superadd the punishment of
death. Incorrigible offenders on these matters were "left" to the
secular power, to be corrected with due "animadversion." This provision
of the fourth Lateran Council in 1215 was always interpreted to mean
death (see Van Espen, _Observ. in Conc. Lat. IV. Canones_, and the
decree in the _Sext. ut inquisitionis negotium_; and, as to English law
and practice, Maitland, op. cit., Essay vi., and pp. 161, 176; 2 Hen.
IV. c. 15; Fitzherbert, _Natura brevium_, 269; 2 Hen. V. st. 1, c. 7).
The "capital" punishment was generally (always in England) by burning.
Burning was an English punishment for some secular offences.

The Concordat with Francis I. by which the pope gave up the right of
hearing appeals from France was not many years before the legislation of
Henry VIII. in England. Both monarchs proceeded on the same lines; but
Francis I. got the pope's consent: Henry VIII. acted _in invitum_, and
in time went rather further.


  Ecclesiastical jurisdiction in England.

The Statute of Appeals (24 Hen. VIII. c. 12) takes away appeals to Rome
in causes testamentary and matrimonial and in regard to right of tithes,
oblations and obventions. A final appeal is given to the archbishop of
the particular province; but in causes touching the king a final appeal
is given to the Upper House of Convocation of the province. The statute
is aimed at appeals; but the words used in it concerning "citations and
all other processes" are wide enough to take away also the "original"
jurisdiction of the pope. No appeal was yet given to the crown.
Canterbury, York, Armagh, Dublin, Cashel and Tuam are put in the place
of Rome. The English and Irish provinces are treated as self-contained.
All ends there.

The "Act of Submission of the Clergy" (25 Hen. VIII. c. 19) took away
_all_ appeals to Rome and gave a further appeal, "for lack of justice,"
from the several courts of the archbishops to the king in chancery.
Thence a commission was to issue to persons named therein to determine
the appeal definitely. This was copied from the then existent practice
in admiralty appeals and was the origin of the so-called court of
delegates. It is a moot question whether this statute took away the
appeal to the Upper Houses of the various convocations in causes wherein
the king was concerned (see _Gorham_ v. _Bishop of Exeter_, 15 Q.B. 52;
_Ex parte Bishop of Exeter_, 10 C.B. 102; _Re Gorham_ v. _Bishop of
Exeter_, 5 Exch. 630). 37 Hen. VIII. c. 17 provided that married laymen
might be judges of the courts Christian if they were doctors of civil
law, created in any university. This qualification even was considered
unnecessary in Charles I.'s time (_Cro. Car._ 258). Canon 127 of 1603
provided that the judges must be learned in the civil and ecclesiastical
laws and at least masters of arts or bachelors of laws. Canon Law as a
study had been practically prohibited at the universities since 1536
(Merriman, _Thomas Cromwell_, i. 142-143; _Cal. State Papers_, vol. ix.
p. xxix. 117; Owen, _Institutes of Canon Law_, viii.). The substitution
of "civilians," rather than common lawyers, for canonists (civilians,
hitherto, not an important body in England) had important consequences
(see Maitland, op. cit. 92 et seq.).

Henry VIII. had exercised his jurisdiction as Supreme Head through a
vicar-general. Edward VI. exercised original jurisdiction in spiritual
causes by delegated commissions (see Archdeacon Hale, _Precedents in
Criminal Cases_, p. xlviii.). Unless the king was to be regarded as an
ecclesiastical person, they were not properly ecclesiastical courts;
although spiritual persons might sit in them, for they sat only as royal
commissioners. The same point has been taken by large bodies of clergy
and laity in regard to the court of final appeal created by 25 Hen.
VIII. c. 19 and its present successor the judicial committee of Privy
Council (_infra: Rep. Com. Ecc. Discipline_, pp. 9, 94 et seq.). At any
rate the "original" jurisdiction claimed for the monarch personally and
his delegates, under Henry VIII. and Edward VI., has not permanently
remained. In theory, Hooker's contentions have been conceded that "kings
cannot in their own proper persons decide questions about matters of
faith and Christian religion" and that "they have not ordinary spiritual
power" (_Ecc. Pol._ vii. 8, 1, 6; cf. _XXXIX. Articles_, Art. 37).

Under Henry VIII. a system began of making certain crimes, which
previously had been only of spiritual cognizance, felonies (25 Hen.
VIII. c. 6), excluding thereby spiritual jurisdiction (Stephen, _Hist.
Crim. Law_, ii. 429). Bigamy (in its modern sense) was thus made felony
(1 Jac. I. c. 11). In this reign and the next, temporal courts were
sometimes given jurisdiction over purely spiritual offences. A trace of
this remains in 1 Edw. VI. c. 1 (still on the statute book; Stephen,
_Hist. Crim. Law_, ii. 439). Other traces occur in the Acts of
Uniformity, which make offences of depraving the Book of Common Prayer
triable at Assizes (between 23 Eliz. c. 1 and 7 & 8 Vict. c. 102--also
at Sessions) as well as in the courts Christian.

During Edward VI.'s time the courts Christian seem practically to have
ceased to exercise criminal jurisdiction (Hale, _Precedents in Criminal
Cases_, p. xlix.). But they sat again for this purpose under Mary and
Elizabeth and (save between 1640 and 1661) continued regular criminal
sessions till towards the end of the 17th century as continuously and
constantly as the king's courts (op. cit.).

The "ordinary" ecclesiastical tribunals of the later middle ages still
subsist in England, at least as regards the laity. This is hardly the
case elsewhere in the Western Church, though some exceptions are noted
below. Nevertheless, their exercise of criminal jurisdiction over the
laity is now in practice suspended; although in law it subsists (see
Stephen, _Hist. Crim. Law_; _Ray_ v. _Sherwood_, 1 Curt. R. 193; 1 Moore
P.C.R. 363; the observations of Kelly, C.B., in _Mordaunt_ v.
_Moncrieffe_, L.R. 2 Sc. & Div. 381, and of Lord Coleridge in _Martin_
v. _Mackonochie_, L.R. 4 Q.B.D. 770, and, on the other hand, of Lord
Penzance in _Phillimore_ v. _Machon_, L.R. 1 P.D. 480). Theoretically
still, in cases of sexual immorality, penance may be imposed. Monitions
to amend may be decreed and be enforced by _significavit_ and writ _de
contumace capiendo_, or by excommunication with imprisonment not to
exceed six months (53 Geo. III. c. 127). The tribunals thus subsisting
are the courts of the bishop and archbishop, the latter sometimes called
the court of appeal of the province. Peculiar jurisdictions have been
gradually taken away under the operation of the acts establishing the
ecclesiastical commissioners. The appeal given to delegates appointed by
the crown has been transferred, first by 2 & 3 Will. IV. c. 92 to the
privy council, and then by 3 & 4 Will. IV. c. 41 to the judicial
committee of the privy council. Bishops may now be summoned as assessors
by 39 & 40 Vict. c. 59.

There was in the time of Elizabeth, James I. and Charles I. a "Court of
High Commission" with jurisdiction over laity and clergy, based on 1
Eliz. c. i. s. 15, which was reckoned as an ecclesiastical judicature (5
R. 1, _Cawdrey's case_) concurrent with the ordinary court Christian. It
was created by virtue of the royal supremacy, and was taken away by 16
Car. I. c. 11. As to its history see Stephen, _Hist. Crim. Law_, ii.
414-428.

In regard to clerical offences, 3 & 4 Vict. c. 86 (the "Church
Discipline Act") creates new tribunals; and first a commission of
inquiry appointed by the bishop of five persons, of whom the
vicar-general, or an archdeacon, or a rural dean of the diocese must be
one. If they report a _prima facie_ case, the bishop may (with the
consent of parties) proceed to sentence. In the absence of such
consent, the bishop may hear the cause with three assessors, of whom one
shall be a barrister of seven years' standing and another the dean of
the cathedral, or one of the archdeacons, or the chancellor. This court
is called the "consistory" court, but is not the old consistory. Both
these tribunals are new. But the bishop may instead send the cause, in
first instance, to the old provincial court, to which appeal lies, if it
be not so sent.

The Public Worship Regulation Act (37 & 38 Vict. c. 85) gave criminal
jurisdiction over beneficed clerks (concurrent with that of the tribunal
under 3 & 4 Vict. c. 86) to the judge under the act in matters of the
fabric, ornaments, furniture and decorations of churches, and the
conduct of divine service, rites and ceremonies. The "judge" under the
act is to be a barrister of ten years' standing, or an ex-judge of a
superior secular court, appointed by the archbishops of Canterbury and
York, with the approval of the crown, or, if they fail to appoint, by
the crown. Proceedings under this act are to be deemed to be taken in
the appropriate ancient ecclesiastical courts (_Green_ v. _Lord
Penzance_, 6 A. C. 657). The judge under this act became (upon vacancies
occurring) _ex officio_ official principal of the arches court of
Canterbury and of the chancery court of York. This provision caused
grave doubts to be entertained as to the canonical position of this
statutory official principal.

Finally, the Clergy Discipline Act 1892 (55 & 56 Vict. c. 32) creates
yet a new court of first instance for the trial of clerical offences
against morality in the shape of a consistory court, which is not the
old court of that name, but is to comprehend the chancellor and five
assessors (three clergymen and two laymen chosen from a prescribed
list), with equal power with the chancellor on questions of fact. In
many instances the conviction of a temporal court is made conclusive on
the bishop without further trial. In regard to moral offences,
jurisdiction under this act is exclusive. But it only applies to clerks
holding preferment. Under all these three acts there is a final appeal
to the judicial committee of the privy council.

None of these acts applies to the trial of bishops, who are left to the
old jurisdictions, or whatever may be held to be the old jurisdictions
(with that of the Roman See eliminated). As to suffragan bishops in the
province of Canterbury, see _Read_ v. _Bishop of Lincoln_, 13 P.D. 221,
14 P.D. 88. (On general questions see Phillimore, _Ecc. Law_, 65, 73.)
Despite the bishop of Lincoln's case, the law is in some uncertainty.

Dilapidations are now not made matters of suit before the court, but of
administrative action by the bishop.

The subject matter of ecclesiastical jurisdiction has been gradually
reduced in England, &c., by various causes. (1) The taking away of all
matrimonial, testamentary and _ab intestate_ jurisdiction by 20 & 21
Vict. c. 77 (testamentary, &c., England), c. 79 (testamentary, &c.,
Ireland), c. 85 (matrimonial, England); 33 & 34 Vict. c. 110
(matrimonial, Ireland). Matrimonial jurisdiction was taken from the
bishop of Sodor and Man in 1884. (2) Since 6 & 7 Will. IV. c. 71, tithe
has become, except in a few rare cases, tithe rent charge, and its
recovery has been entirely an operation of secular law. Most kinds of
offerings are now recoverable in secular courts. (3) Administration of
pious gifts has passed to the court of chancery. (4) The enforcement of
contractual promises has long been abandoned by the courts Christian
themselves. (5) Church rates can no longer be enforced by suit (31 & 32
Vict. c. 109). (6) _Defamation_ was taken away in England by 18 & 19
Vict. c. 41, and in Ireland by 23 & 24 Vict. c. 32. (7) Laymen can no
longer be tried in the spiritual courts for offences against clerks. (8)
The jurisdiction for "brawling" in church, &c., is taken away by 23 & 24
Vict. c. 32 in the case of the laity. In the case of persons in holy
orders there is a concurrent jurisdiction of the two tribunals
(_Valancy_ v. _Fletcher_, 1897, 1 Q.B. 265). This was an offence very
frequently prosecuted in the courts Christian (see A.J. Stephens,
_Ecclesiastical Statutes_, i. 336).

The existing ecclesiastical jurisdiction in England is therefore now
confined to the following points. (1) Discipline of the clergy. (2)
Discipline of the laity in respect of sexual offences as already
stated. (3) Control of lay office-bearers, church-wardens, sidesmen,
organists, parish clerks, sextons. (4) Protection of the fabrics of
churches, of churchyards, ornaments, fittings, &c., sanctioning by
licence or faculty any additions or alterations, and preventing or
punishing unauthorized dealings by proceedings on the criminal side of
the courts. (5) Claims by individuals to particular seats in church or
special places of sepulture. (6) Rare cases of personal or special
tithes, offerings or pensions claimed by incumbents of benefices. In the
Isle of Man and the Channel Islands courts Christian have now
jurisdiction substantially as in England. In Jersey and in Guernsey
there are courts of first instance with appeal to the bishop of
Winchester. Ecclesiastical jurisdiction in Ireland was as in England
till the Irish Church was disestablished in 1869 by 32 & 33 Vict. c. 42.


  Ecclesiastical jurisdiction in non-established churches.

The position of a disestablished or an unestablished Church is
comparatively modern, and has given rise to new jural conceptions. These
Churches are _collegia licita_ and come within the liberty of
association so freely conceded in modern times. The relations of their
bishops, priests or other ministers and lay office-bearers _inter se_
and to their lay folk depend upon contract; and these contracts will be
enforced by the ordinary courts of law. A consensual ecclesiastical
jurisdiction is thus created, which has to this extent temporal
sanction. _In foro conscientiae_ spiritual censures canonically imposed
are as binding and ecclesiastical jurisdiction is as powerful as ever.

Into the British-settled colonies no bishops were sent till 1787; and
consequently there were no regular courts Christian. The bishop of
London was treated as the diocesan bishop of the colonists in North
America; and in order to provide for testamentary and matrimonial
jurisdiction it was usual in the letters patent appointing the governor
of a colony to name him ordinary. In New York state there is still a
court called the surrogates court, surrogate being the regular name for
a deputy ecclesiastical judge. In Lower Canada, by treaty, the Roman
Catholic Church remained established.

Throughout the United States, whatever may have been the position in
some of them before their independence, the Church has now no position
recognized by the State, but is just a body of believers whose relations
are governed by contract and with whom ecclesiastical jurisdiction is
consensual.

The position is the same now through all the British colonies (except,
as already mentioned, Lower Canada or Quebec). From 1787 onwards,
colonial bishops and metropolitans were appointed by letters patent
which purported to give them jurisdiction for disciplinary purposes. But
a series of cases, of which the most remarkable was that _Re the Bishop
of Natal_ (3 Moore P.C. N.S. A.D. 1864), decided that in colonies
possessing self-governing legislatures such letters patent were of no
value; and soon after the crown ceased to issue them, even for crown
colonies.

In India the metropolitan of Calcutta and the bishops of Madras and
Bombay have some very limited jurisdiction which is conferred by letters
patent under the authority of the statutes 53 Geo. III. c. 155 and 3 & 4
Will. IV. c. 85. But the other Indian bishops have no position
recognized by the State and no jurisdiction, except consensual.


  Ecclesiastical jurisdiction in Scotland.

The Church had the same jurisdiction in Scotland, and exercised it
through similar courts to those which she had in England and France,
till about 1570. As late as 1566 Archbishop Hamilton of Glasgow, upon
his appointment, had restitution of his jurisdiction in the probate of
testaments and other matters (Keith, _History of the Scottish Bishops_,
Edinburgh, 1824, p. 38). There was an interval of uncertainty, with at
any rate titular bishops, till 1592. Then parliament enacted a new
system of Church courts which, though to some extent in its turn
superseded by the revival of episcopacy under James VI., was revived or
ratified by the act of 1690, c. 7, and stands to this day. It is a
Presbyterian system, and the Scottish Episcopal Church is a
disestablished and voluntary body since 1690.

The Presbyterian courts thus created are arranged in ascending order:--

(a) _Kirk Session_ consists of the minister of the parish and the
"ruling elders" (who are elected by the session). It has cognizance of
scandalous offences by laymen and punishes them by deprivation of
religious privileges. It does not judge ministers (Brodie-Innes,
_Comparative Principles of the Laws of England and Scotland_, 1903, p.
144).

(b) The _Presbytery_ has jurisdiction, partly appellate and partly
original, over a number of parishes. There are now eighty-four
presbyteries. These courts consist of every parochial minister or
professor of divinity of any university within the limits, and of an
elder commissioned from every kirk session. A minister is elected to
preside as moderator. These courts judge ministers in first instance for
scandalous conduct. As civil courts they judge in first instance all
questions connected with glebes and the erection and repair of churches
and manses. They regulate matters concerning public worship and
ordinances, and have appellate jurisdiction from the kirk session.

(c) The _Provincial Synod_ consists of a union of three or more
presbyteries with the same members. There are now sixteen. They meet
twice a year to hear appeals from presbyteries. No appeal can go direct
to the General Assembly, _omisso medio_, unless the presbytery have so
expressly directed, or unless there be no meeting of synod after the
decision of the presbytery before the meeting of General Assembly.

(d) The _General Assembly_ is the supreme ecclesiastical court of this
system. It meets annually. The king's "lord high commissioner" attends
the sittings; but does not intervene or take part in the court's
decisions. The court consists of ministers and elders, elected from the
presbyteries in specified proportions, and of commissioners from the
four universities, the city of Edinburgh and the royal burghs. The
Presbyterian Church in India sends one minister and one elder. The whole
Assembly consists of 371 ministers and 333 elders. The jurisdiction is
entirely appellate. The Assembly appoints a commission to exercise some
of its functions during the intervals of its session. To this commission
may be referred the cognizance of particular matters.

Questions of _patronage_ now (by 37 & 38 Vict. c. 82) belong to the
Church courts; but not questions of _lapse_ or _stipend_. Seats, seat
rents, pews, the union and disjunction of parishes and formation of
district parishes are of secular jurisdiction. Questions of tithes (or
"teinds") and ministers' stipends were referred to commissioners by acts
of the Scots parliaments beginning in 1607. The commissioners of teinds
became a species of ecclesiastical court. By Scots act of 1707, c. 9,
their powers were transferred to the judges of the court of session, who
now constitute a "teind court" (Brodie-Innes, op. cit. pp. 138, 139).
Matrimonial matters and those relating to wills and succession (called
in Scotland "consistorial" causes) were in 1563 taken from the old
bishops' courts and given to "commissaries" appointed by the crown with
an appeal to the court of session, which by act 1609, c. 6, was declared
the king's great consistory. They have remained matters of secular
jurisdiction.

The Scots ecclesiastical courts are entitled to the assistance of the
secular courts to carry out their jurisdiction by "due assistance."
Within the limits of their jurisdiction they are supreme. But if a court
go outside its jurisdiction, or refuse to exercise powers conferred on
it by law, the civil court may "reduce" (i.e. set aside) the sentence
and award damages to the party aggrieved.


  Protestant continental European states.

With the Reformation in the 16th century, Church courts properly
speaking disappeared from the non-episcopal religious communities which
were established in Holland, in the Protestant states of Switzerland and
of Germany, and in the then non-episcopal countries of Denmark and
Norway.

Discipline over ministers and other office-bearers was exercised by
administrative methods in the form of trials before consistories or
synods. To this extent ecclesiastical jurisdiction is still exercised in
these countries. Consistories and synods have exercised discipline of a
penitential kind over their lay members; but in later times their
censures have generally ceased to carry temporal consequences.
Ecclesiastical jurisdiction on the civil side for the trial of causes
soon disappeared. Heresy has been treated as a crime to be tried in and
punished by the ordinary courts of the country, as in the cases of
Servetus (q.v.) and Grotius (q.v.).

For the episcopal churches of Sweden and Finland the first constitution
or "Church order" was formed in 1571. It provided for the visitation of
the clergy by the bishop, and for the power of the clergy to exclude
their lay folk from the Holy Communion, subject to appeal to the bishop.
Both minor and major excommunication had been in use, and for a long
time public penance was required. The procedure underwent great
modification in 1686; but public penance was not taken away till 1855,
and then confession to and absolution by the priest in the presence of
witnesses was still required. Civil jurisdiction in causes appears to
have been given up early (Cornelius, _Svenska Kirkaus Historia_, Upsala,
1875, pp. 146, 186, 189, 285).


  Roman Catholic countries.

Over the rest of western continental Europe and in the colonies of
Spain, Portugal and France, ecclesiastical jurisdiction remained
generally in the state which we have already described till near the end
of the 18th century. The council of Trent took away the jurisdiction of
archdeacons in marriage questions. The testamentary jurisdiction
disappeared (as already stated) in France. Disputed cases of contract
were more often tried in the secular courts. Recourse to the secular
prince by way of _appel comme d'abus_, or otherwise, became more
frequent and met with greater encouragement. Kings began to insist upon
trying ecclesiastics for treason or other political crimes in secular
courts. So under the advice of his minister (the marquis of Pombal),
King Joseph of Portugal in 1759-1760 claimed that the pope should give
him permission to try in all cases clerics accused of treason, and was
not content with the limited permission given to try and execute, if
guilty, the Jesuits then accused of conspiring his death (_Life of
Pombal_, by Count da Carnota, 1871, pp. 128, 141). But there was no
sudden change in the position of the courts Christian till the French
Revolution.

In France a law of the Revolution (September 1790) purported to suppress
all ecclesiastical jurisdictions. On the re-establishing of the Catholic
religion on the basis of the new Concordat, promulgated 18 Germinal,
year X. (April 8, 1802), no express provision was made for
ecclesiastical jurisdictions; but several bishops did create new
ecclesiastical tribunals, "officialities" (Migne, _Dict. de droit
canon._, s.v.). The government in some cases recognized these tribunals
as capable of judging ecclesiastical causes (Migne, _ubi sup._). In 1810
the diocesan official of Paris entertained the cause between Napoleon
and Josephine, and pronounced a decree of nullity (Migne, _ubi sup._
s.v. "Causes"). Such litigation as still continued before the spiritual
forum was, however, confined (save in the case of the matrimonial
questions of princes) to the professional conduct of the clergy.

Such neighbouring countries as were conquered by France or
revolutionized after her pattern took the same course of suppressing
their ecclesiastical jurisdictions. After 1814, some of these
jurisdictions were revived. But the matter is now determined for all
countries which have adopted codes, whether after the pattern of the
Code Napoléon or otherwise. These countries have created a hierarchy of
temporal courts competent to deal with every matter of which law takes
cognizance, and a penal code which embraces and deals with all crimes or
delicts which the state recognizes as offences. Hence, even in countries
where the Roman Church is established, such as Belgium, Italy, the
Catholic states of Germany and cantons of Switzerland, most of the Latin
republics of America, and the province of Quebec, and _a fortiori_ where
this Church is not established, there is now no discipline over the
laity, except penitential, and no jurisdiction exercised in civil suits,
except possibly the matrimonial questions of princes (of which there was
an example in the case of the reigning prince of Monaco). In Spain
causes of nullity and divorce _a thoro_, in Portugal causes of nullity
between Catholics, are still for the court Christian. In Peru, the old
ecclesiastical matrimonial jurisdiction substantially remains (Lehr, _Le
Mariage dans les principaux pays_, 1899, arts. 362, 797, 772, 781).
Otherwise these three countries are Code countries. In Austria, the
ancient ecclesiastical jurisdiction was taken away by various acts of
legislation from 1781 to 1856; even voluntary jurisdiction as to
dispensations. The Concordat of 1856 and consequent legislation restored
matrimonial jurisdiction to the courts Christian over marriages between
Roman Catholics. In 1868 this was taken away. The Austrian bishops,
however, maintain their tribunals for spiritual purposes, and insist
that such things as divorce _a vinculo_ must be granted by their
authority (Aichner, _Compendium juris ecclesiastici_, pp. 551-553).

By consent and submission of her members, the Roman Church decides _in
foro conscientiae_ questions of marriage, betrothal and legitimacy
everywhere; but no temporal consequences follow except in Spain,
Portugal and Peru.

The position in France was the same as that in Belgium, Italy, &c., till
1906, when the Church ceased to be established. The only Latin countries
in which conflict has not arisen appear to be the principality of
Andorra and the republic of San Marino (Giron y Areas, _Situación
jurídica de la Iglesia Católica_, Madrid, 1905, p. 173 et seq.).

Even as to the discipline of the Roman clergy it is only in certain
limited cases that one can speak of ecclesiastical jurisdiction. Bishops
and beneficed incumbents (_curés_) must be regularly tried; and where
the Church is established the canonical courts are recognized. But the
majority of parishes are served by mere _desservants_ or _vicaires_, who
have no rights and can be recalled and dismissed by mere administrative
order without trial (Migne, _ubi sup._ s.v. "Inamovibilité,"
"Desservants").

The Napoleonic legislation re-established the _appel comme d'abus_
("_Articles organiques_," art. 6). The recourse was now to the council
of state (see Migne, _ubi supra_, "Officialité"). But the revocation of
a _desservant_, and the forbidding him the execution of his ministry in
the diocese, was not a case in which the council of state would
interfere (Migne, _ubi sup._ "Appel comme d'abus," "Conseil d'état").


  Jurisdiction in Anglican communion.

In those provinces of the Anglican communion where the Church is not
established by the state, the tendency is not to attempt any external
discipline over the laity; but on the other hand to exercise consensual
jurisdiction over the clergy and office-bearers through courts nearly
modelled on the old canonical patterns.


  Modern jurisdiction of Church of Rome.

In the Roman communion, on the other hand, both where the Church is
established and where it is not, the tendency is to reduce the status of
_curé_ to that of _desservant_, and to deal with all members of the
priestly or lower orders by administrative methods. This practice
obtains in all missionary countries, e.g. Ireland and also in Belgium
(S.B. Smith, _Elements of Ecclesiastical Law_, New York, i. 197 et seq.;
p. 403 et seq.; Tauber, _Manuale juris canonici_, Sabariae, 1904, p.
277). In the United States, the 3rd plenary council of Baltimore in 1884
provided that one rector out of ten should be irremovable (Smith, op.
cit. i. 197, 419). In England there are few Roman "benefices" (E.
Taunton, _Law of the Church_, London, 1906, s.v. "Benefice"). A
_desservant_ has an informal appeal, by way of recourse, to the
metropolitan and ultimately to the pope (Smith, op. cit. p. 201). The
bishop's "official" is now universally called his vicar-general (except
in France, where sometimes an _official_ is appointed _eo nomine_), and
generally exercises both voluntary and contentious jurisdiction (op.
cit. i. 377). As of old, he must be at least tonsured and without a wife
living. At the Vatican Council, a desire was expressed that he should be
a priest (ib.). He should be a doctor in theology or a licentiate in
canon law (ib. p. 378). Whether a bishop is bound to appoint a
vicar-general is still disputed (ib. p. 380; cf. _supra_; _contra_,
Bouix, _Inst. Juris Canon. De Judic._ i. 405). In 1831 the pope enacted
that in all the dioceses of the then Pontifical States, the court of
first instance for the criminal causes of ecclesiastics should consist
of the ordinary and four other judges. In the diocese of Rome, the
court of the cardinal vicar-general consists of such vicar-general and
four other prelates (Smith, _ubi supra_). In the Roman communion in
England and the United States, there are commissions of investigation
appointed to hear in first instance the criminal causes of clerks. They
consist of five, or at least three, priests nominated by the bishop in
and with the advice of the diocesan synod. In the United States, since
1884, the bishop presides on these commissions. They report their
opinions to the bishop, who passes final sentence (ib. ii. 129-131).

"Exemptions" now include all the regular religious orders, i.e. those
orders which have solemn vows. Over the members of these orders their
superiors have jurisdiction and not the bishop. Otherwise if they live
out of their monastery, or even within that enclosure so notoriously
offend as to cause scandal. In the first case, they may be punished by
the ordinary of the place, acting as delegate of the pope without
special appointment (_Conc. Trid. Sess._ vi. c. 3). In the second case,
the bishop may require the superior to punish within a certain time and
to certify the punishment to him; in default he himself may punish
(_Conc. Trid. Sess._ xxv. c. 14, cf. Smith, op. cit. i. 204-206). So,
regulars having cure of souls are subject to the jurisdiction of the
bishop in matters pertaining thereto (ib. p. 206). The exemption of
regular religious orders may be extended to religious societies without
solemn vows by special concession of the pope, as in the case of the
Passionists and Redemptorists (ib. p. 205; Sanguineti, _Juris ecc.
inst._, Rome, 1800, pp. 393, 394).

Appeal lies, in nearly all cases, to the metropolitan (Smith, op. cit.
pp. 219-223). Metropolitans usually now have a metropolitan tribunal
distinct from their diocesan court (ib. ii. 141), but constructed on the
same lines, with the metropolitan as judge and his vicar-general as
vice-judge. In some "missionary" dioceses, the metropolitan, _qua_
metropolitan, has a separate commission of investigation, to try the
criminal causes of clerks, sentence being passed by himself or his
vicar-general (ib. p. 142).

The next step in the hierarchy, that of "primates" (_supra_), has "in
the present state of the Church" ceased to exist for our purpose
(Sanguineti, op. cit. p. 334), as a result of Tridentine legislation.
The only appellate jurisdiction from the metropolitans is the Roman See.
To it also lies a direct appeal from the court of first instance,
_omisso medio_ (Smith, op. cit. i. 224). The pope's immediate and
original jurisdiction in every diocese is now expressly affirmed by the
Vatican Council (ib. p. 239). That original jurisdiction he reserves
exclusively to himself in _causis majoribus_ (ib. pp. 249-250). These
are (1) causes relating to elections, translations and deprivations of,
and criminal prosecutions against, bishops, and (2) the matrimonial
cases of princes (Taunton, op. cit. s.v. "Cause").


  Eastern Church.

In the Eastern Church, the early system of ecclesiastical judicature
long continued. But a sacred character was ascribed to the emperors.
They are "anointed lords like the bishops" (Balsamon, in _Conc. Ancyr.
Can._ xii., representing the view of the 12th and 13th centuries).
Bishops were often deposed by administrative order of the emperor;
synods being expected afterwards to confirm, or rather accept, such
order. The germ of this dealing with a _major causa_ may be found in the
practice of the Arian emperors in the 4th century. The cause of Ignatius
and Photius was dealt with in the 9th century by various synods; those
in the East agreeing with the emperor's view for the time being, while
those in the West acted with the pope. (The details are in Mansi, _Conc.
in locis_, and in Hefele, _Conc. in locis_, more briefly. They are
summarized in Landon, _Manual of Councils_, s.v. "Constantinople,"
"Rome," and in E.S. Foulkes, _Manual of Ecclesiastical History_, s.v.
"Century IX.") Since these transactions patriarchs have been deposed by
the Byzantine emperors; and the Turkish sultans since the 15th century
have assumed to exercise the same prerogative.

The spiritual courts in the East have permanently acquired jurisdiction
in the matrimonial causes of baptized persons; the Mahommedan
governments allowing to Christians a personal law of their own. The
patriarch of Constantinople is enabled to exercise an extensive
criminal jurisdiction over Christians (Neale, _Hist. of the Eastern
Church_, i. 30, 31).

The empire of Russia has in the matter of ecclesiastical jurisdiction
partly developed into other forms, partly systematized 4th century and
later Byzantine rules. The provincial system does not exist; or it may
be said that all Russia is one province. An exception should be made in
the case of Georgia, which is governed by an "exarch," with three
suffragans under him. In the remainder of the empire the titles of
metropolitan, save in the case of the metropolitan of all Russia, and of
archbishop, were and are purely honorary, and their holders have merely
a diocesan jurisdiction (see Mouravieff, _History of the Russian
Church_, translated Blackmore, 1842, translator's notes at pp. 370, 390,
416 et seq.). So in Egypt the bishop or "pope" (afterwards patriarch) of
Alexandria was the only true metropolitan (Neale, _History of the
Eastern Church_, Gen. Introd. vol. i. p. 111). The metropolitan of
Russia from the time of the conversion (A.D. 988) settled at Kiev, and
his province was part of the patriarchate of Constantinople, and appeals
lay to Constantinople. Many such appeals were taken, notably in the case
of Leon, bishop of Rostov (Mouravieff, op. cit. p. 38). The
metropolitical see was for a short time transferred to Vladimir and then
finally to Moscow (Mouravieff, chs. iv., v.). After the taking of
Constantinople in 1452, the Russian metropolitans were always chosen and
consecrated in Russia, appeals ceased, and Moscow became _de facto_
autocephalous (Joyce, ubi sup. p. 379; Mouravieff, op. cit. p. 126). The
tsar Theodore in 1587 exercised the power of the Byzantine emperors by
deposing the metropolitan, Dionysius Grammaticus (Mouravieff, p. 125).
In 1587 the see of Moscow was raised to patriarchal rank with the
consent of Constantinople, and the subsequent concurrence of Alexandria,
Antioch and Jerusalem (ib. c. vi.). Moscow became the final court, in
theory, as it had long been in practice. Certain religious houses,
however, had their own final tribunals and were "peculiars," exempt from
any diocesan or patriarchal jurisdiction for at least all causes
relating to Church property (ib. p. 131).

The subject matter of ecclesiastical jurisdiction in Russia during the
whole patriarchal period included matrimonial and testamentary causes,
inheritance and sacrilege, and many questions concerning the Church
domains and Church property, as well as spiritual offences of clergy and
laity (ib.). The bishops had consistorial courts; the patriarchs,
chanceries and consistories (ib.). Bishops were judged in synod (see,
e.g. the case of the archbishop of Polotsk in 1622, ib. p. 179) and only
lawfully judged in synod (ib. p. 215).

Clerks and the dependants of the metropolitan (afterwards the patriarch)
appear to have been immune from secular jurisdiction, except in the case
of crimes against life, from the time of Ivan the Terrible (ib. pp.
180-181). The tsar Michael, in the earlier 17th century, confirmed these
immunities in the case of the clergy of the patriarch's own diocese, but
provided that in country places belonging to his diocese, monasteries,
churches and lands should be judged in secular matters by the Court of
the Great Palace, theoretically held before the tsar himself (ib. p.
181). This tsar limited the "peculiar" monasteries to three, and gave
the patriarch jurisdiction over them (ib.). The next tsar, Alexis,
however, by his code instituted a "Monastery Court," which was a secular
tribunal composed of laymen, to judge in civil suits against spiritual
persons, and in matters arising out of their manors and properties (ib.
p. 193). This court was not in operation during the time when the
patriarch Nikon was also in effect first minister; but upon his decline
exercised its full jurisdiction (ib. p. 216). Nikon was himself tried
for abdicating his see, causing disorder in the realm, oppression and
violence, first before a synod of Moscow composed of his suffragans and
some Greek bishops, and afterwards before another synod in which sat the
patriarchs of Alexandria and Antioch, the metropolitans of Servia and
Georgia, the archbishops of Sinai and Wallachia, and the metropolitans
of Nice, Amasis, Iconium, Trebizond, Varna and Scio, besides the Russian
bishops. This synod in 1667 deposed Nikon, degraded him from holy
orders, and sentenced him to perpetual penance in a monastery (ib. pp.
220-232). The next tsar, Theodore, suppressed the secular "monastery
court," and directed that all suits against spiritual persons should
proceed only in the patriarchal "court of requests" (ib. p. 264). There
was, however, a species of _appel comme d'abus_. Causes could be evoked
to the tsar himself, "when any partiality of the judges in any affair in
which they themselves were interested was discovered" (ib.).

The old system was swept away by Peter the Great, who settled
ecclesiastical jurisdiction substantially on its present basis. The
patriarchate was abolished and its jurisdiction transferred by a council
at St Petersburg in 1721 to a Holy Governing Synod. The change was
approved by the four patriarchs of the East in 1723 (ib. chs.
xv.-xvii.). Peter permanently transferred to the secular _forum_ the
testamentary jurisdiction and that concerning inheritance, as also
questions of "sacrilege" (ib. p. 264). As the result of a long series of
legislation, beginning with him and ending with Catherine II., all
church property of every kind was transferred to secular administration,
allowances, according to fixed scales, being made for ministers, monks
and fabrics (op. cit. translator's appendix i. p. 413 et seq.). There
remain to the spiritual courts in Russia the purely ecclesiastical
discipline of clerks and laity and matrimonial causes.

The court of first instance is the "consistorial court" of the bishop.
This consists of a small body of ecclesiastics. Its decisions must be
confirmed by the bishop (op. cit. translator's appendix ii. pp.
422-423). In the more important causes, as divorce (i.e. _a vinculo_),
it only gives a provisional decision, which is reported by the bishop,
with his own opinion, for final judgment, to the Most Holy Governing
Synod.

The governing synod is the final court of appeal. It consists of a small
number of bishops and priests nominated by the tsar, and is assisted by
a "procurator," who is a layman, who explains to it the limits of its
jurisdiction and serves as the medium of communication between it and
the autocrat and secular authorities. It deals with the secular crimes
of spiritual persons, if of importance and if not capital (these last
being reserved for the secular forum), and with heresy and schism. It is
the only court which can try bishops or decree divorce. The tsar
formally confirms its judgments; but sometimes reduces penalties in the
exercise of the prerogative of mercy (see Mouravieff, op. cit. ch. xvii.
translator's app. ii.).

The governing synod now sits at St Petersburg, but appoints delegated
commissions, with a portion of its jurisdiction, in Moscow and Georgia.
The latter commission is presided over by the "exarch" (_supra_).

Since the War of Independence, the kingdom of Greece has been
ecclesiastically organized after the model of Russia, as one
autocephalous "province," separated from its old patriarchate of
Constantinople, with an honorary metropolitan and honorary archbishops
(Neale, op. cit. Gen. Introd. vol. i.). The Holy Synod possesses the
metropolitical jurisdiction. It sits at Athens. The metropolitan of
Athens is president, and there are four other members appointed by the
government in annual rotation from the senior bishops. There is attached
to it a government commissioner, with no vote, but affixing his
signature to the synodical judgments (Joyce, op. cit. p. 35).

The subject matter of the jurisdiction of Hellenic courts Christian
seems to be confined to strictly spiritual discipline, mainly in regard
to the professional misconduct of the clergy. Imprisonment may be
inflicted in these last cases (ib.). All matrimonial causes are heard by
the secular tribunals (Lehr, op. cit. sec. 587).

The bishop's consistorial court, consisting of himself and four priests,
has a limited jurisdiction in first instance. Such a court can only
suspend for seven days unless with the sanction of the Holy Synod
(Joyce, op. cit.).

The Holy Synod can only inflict temporary suspension, or imprisonment
for fifteen days, unless with the sanction of the King's ministry.
Deprivation, or imprisonment for more than two months, requires the
approval of the king (ib.). The king or the ministry do not, however,
rehear the cause by way of appeal, but merely restrain severity of
sentence (ib.).

The Church of Cyprus has been autocephalous since at any rate the
oecumenical synod of Ephesus in 431. The episcopate now consists of an
archbishop and three suffragans (Hackett, _Orthodox Church in Cyprus_,
1901, ch. v. _et passim_). The final court is the island synod, which
consists of the archbishop, his suffragans and four dignified priests.
It has original and exclusive cognizance of causes of deposition of
bishops (op. cit. pp. 260, 262).

Each bishop is assisted by at least two officers with judicial or
quasi-judicial powers, the "archimandrite" who adjudicates upon causes
of revenue and the archdeacon who adjudicates on questions between
deacons (op. cit. pp. 272-273). The "exarch" of the archbishop, who is a
dignitary but not a bishop, has a seat in the provincial synod.

In the Balkan States, the system--inherited from Byzantine and Turkish
times--of ecclesiastical jurisdictions prevails, except that they are
now autocephalous, and independent of the patriarch of Constantinople.
Matrimonial causes in Servia are of ecclesiastical cognizance (Lehr, op.
cit. sect. 901).

  AUTHORITIES.--St Augustine, _Epistles_; _Codex Theodosianus_, edited
  by Th. Mommsen and P.M. Meyer (1905); _Code and Novells of Emperor
  Justinian_, ed. J. Gothofredus (1665); T. Balsamon, "In Conc. Ancyr."
  in the _Corpus juris canonici_ (1879-1881); "_Hostiensis_" _Super
  Decretum_; W. Lyndwood, _Provinciale_ (Oxford, 1679); Sir A.
  Fitzherbert, _Natura brevium_ (1534); Sir T. Ridley, _View of the
  Civile and Ecclesiastical Law_ (1607); J. Ayliffe, _Parergon juris
  ecclesiastici_ (1726); J. Godolphin, _Abridgement of the Laws
  Ecclesiastical_ (London, 1687); E. Gibson, _Codex juris ecclesiastici_
  (Oxford, 1761); D. Covarruvias, _Opera omnia_ (Antwerp, 1638); Jean
  Hardouin, _Concilia_ (1715); J.D. Mansi, _Concilia_ (1759-1798); E.
  Stillingfleet, _Ecclesiastical Jurisdiction_ (1704); L.S. le Nain de
  Tillemont, _Mémoires pour servir à l'histoire ecclésiastique_
  (1701-1712); P.T. Durand de Maillane, _Dictionnaire du droit
  canonique_ (1761); _Dictionnaire ecclésiastique et canonique_, par une
  société de religieux (Paris, 1765); Z.B. van Espen, _Jus
  ecclesiasticum universum_ (Louvain, 1720), _De recursu ad Principem,
  observationes in Concilium Lateranense iv._; L. Thomassin, _Vetus et
  nova disciplina ecc._ (1705-1706); W. Beveridge, _Synodicon_ (Oxford,
  1672); J.A.S. da Carnota, _Life of Pombal_ (1843); J.P. Migne,
  _Dictionnaire de droit canon._ (Paris, 1844); R. Keith, _History of
  the Scottish Bishops_ (Edinburgh, 1824); P.N. Vives y Cebriá, _Usages
  y demas derechos de Cataluña_ (1832); C.A. Cornelius, _Svenska Kyrkaus
  Historia_ (Upsala, 1875); Mouravieff, _History of the Russian Church_
  (trans. Blackmore, 1842); Ffoulkes, _Manual of Ecclesiastical History_
  (1851); E.H. Landon, _Manual of Councils of the Church_ (1893); W.H.
  Hale, _Precedents in Criminal Cases_ (London, 1847); E.B. Pusey,
  _Councils of the Church_ (Oxford, 1857); C.J. von Hefele,
  _Conciliengeschichte_ (Freiburg, 1855-1890); M. Gaudry, _Traité de la
  législation des cultes_ (Paris, 1854); W. Stubbs, _Select Charters_
  (Oxford, 1895); A.W. Haddan and W. Stubbs, _Councils and
  Ecclesiastical Documents_ (Oxford, 1869); A.J. Stephens,
  _Ecclesiastical Statutes_ (1845); H.C. Rothery, _Return of Cases
  before Delegates_ (1864); J.W. Joyce, _The Sword and the Keys_ (2nd
  ed., 1881); _Report of Ecclesiastical Courts Commission_ (1888); P.
  Fournier, _Les Officialités au moyen âge_ (1880); S.B. Smith,
  _Elements of Ecclesiastical Law_ (New York, 1889-1890); S. Sanguineti,
  _Juris ecc. inst._ (Rome, 1890); J.F. Stephen, _History of the
  Criminal Law of England_ (London, 1883); Pollock and Maitland,
  _History of English Law before Edward I._ (1898); F.W. Maitland,
  _Roman Canon Law in the Church of England_ (1898); R. Owen, _Canon
  Law_ (1884); Sir R.J. Phillimore, _Ecclesiastical Law_ (2nd ed.,
  1895); J.W. Brodie-Innes, _Comparative Principles of the Laws of
  England and Scotland_ (1903); R.B. Merriman, _Life and Letters of
  Thomas Cromwell_ (1902); S. Aichner, _Compendium juris ecclesiast._
  (8th ed., Brixen, 1905, especially in regard to Austro-Hungarian
  Empire); J. Hackett, _History of the Orthodox Church in Cyprus_
  (1901); Tauber, _Manuale juris canonici_ (1906); E.L. Taunton, _Law of
  the Church_ (London, 1906); _Report of Royal Commission on
  Ecclesiastical Discipline_ (1906).     (W. G. F. P.)



ECCLESIASTICAL LAW, in its broadest sense, the sum of the authoritative
rules governing the Christian Church, whether in its internal polity or
in its relations with the secular power. Since there are various
churches, widely differing alike in their principles and practice, it
follows that a like difference exists in their ecclesiastical law, which
is the outcome of their corporate consciousness as modified by their
several relations to the secular authority. At the outset a distinction
must be made between churches which are "established" and those that are
"free." The ecclesiastical laws of the latter are, like the rules of a
private society or club, the concern of the members of the church only,
and come under the purview of the state only in so far as they come in
conflict with the secular law (e.g. polygamy among the Mormons, or
violation of the trust-deeds under which the property of a church is
held). In the case of "established" Churches, on the other hand,
whatever the varying principle on which the system is based, or the
difference in its practical application, the essential conditions are
that the ecclesiastical law is also the law of the land, the decisions
of the church courts being enforced by the civil power. This holds good
both of the Roman Catholic Church, wherever this is recognized as the
"state religion," of the Oriental Churches, whether closely identified
with the state itself (as in Russia), or endowed with powers over
particular nationalities within the state (as in the Ottoman empire),
and of the various Protestant Churches established in Great Britain and
on the continent of Europe.

Writers on the theory of ecclesiastical law, moreover, draw a fundamental
distinction between that of the Church of Rome and that of the Protestant
national or territorial Churches. This distinction is due to the claim of
the Roman Catholic Church to be the _only_ Church, her laws being thus of
universal obligation; whereas the laws of the various established
Protestant Churches are valid--at least so far as legal obligation is
concerned--only within the limits of the countries in which they are
established. The practical effects of this distinction have been, and
still are, of enormous importance. The Roman Catholic Church, even when
recognized as the state religion, is nowhere "established" in the sense
of being identified with the state, but is rather an _imperium in
imperio_ which negotiates on equal terms with the state, the results
being embodied in concordats (q.v.) between the state and the pope as
head of the Church. The concordats are of the nature of truces in the
perennial conflict between the spiritual and secular powers, and imply in
principle no surrender of the claims of the one to those of the other.
Where the Roman Catholic Church is not recognized as a state religion, as
in the United States or in the British Islands, she is in the position of
a "free Church," her jurisdiction is only _in foro conscientiae_, and her
ecclesiastical laws have no validity from the point of view of the state.
On the other hand, the root principle of the ecclesiastical law of the
established Protestant Churches is the rejection of alien jurisdiction
and the assertion of the supremacy of the state. The theory underlying
this may vary. The sovereign may be regarded, as in the case of the
Russian emperor or of the English kings from the Reformation to the
Revolution, as the vicar of God in all causes spiritual as well as
temporal within his realm. As the first fervent belief in the divine
right of kings faded, however, a new basis had to be discovered for a
relation between the spiritual and temporal powers against which Rome had
never ceased to protest. This was found in the so-called "collegial"
theory of Church government (_Kollegialsystem_), which assumed a sort of
tacit concordat between the state and the religious community, by which
the latter vests in the former the right to exercise a certain part of
the _jus in sacra_ properly inherent in the Church (see PUFENDORF,
SAMUEL). This had great and lasting effects on the development of the
theory of Protestant ecclesiastical law on the continent of Europe. In
England, on the other hand, owing to the peculiar character of the
Reformation there and of the Church that was its outcome, no theory of
the ecclesiastical law is conceivable that would be satisfactory at once
to lawyers and to all schools of opinion within the Church. This has been
abundantly proved by the attitude of increasing opposition assumed by the
clergy, under the influence of the Tractarian movement, towards the civil
power in matters ecclesiastical, an attitude impossible to justify on any
accepted theory of the Establishment (see below).

Protestant ecclesiastical law, then, is distinguished from that of the
Roman Catholic Church (1) by being more limited in its scope, (2) by
having for its authoritative source, not the Church only or even mainly,
but the Church in more or less complete union with or subordination to
the State, the latter being considered, equally with the Church, as an
organ of the will of God. The ecclesiastical law of the Church of Rome,
on the other hand, whatever its origin, is now valid only in so far as
it has the sanction of the authority of the Holy See. And here it must
be noted that the "canon law" is not identical with the "ecclesiastical
law" of the Roman Catholic Church. By the canon law is meant,
substantially, the contents of the _Corpus juris canonici_, which have
been largely superseded or added to by, e.g. the canons of the council
of Trent and the Vatican decrees. The long projected codification of the
whole of the ecclesiastical law of the Church of Rome, a work of
gigantic labour, was not taken in hand until the pontificate of Pius X.
(See also CANON LAW and ECCLESIASTICAL JURISDICTION.)

The ecclesiastical law of England is in complete dependence upon the
authority of the state. The Church of England cannot be said, from a
legal point of view, to have a corporate existence or even a
representative assembly. The Convocation of York and the Convocation of
Canterbury are provincial assemblies possessing no legislative or
judicial authority; even such purely ecclesiastical questions as may be
formally commended to their attention by "letters of business" from the
crown can only be finally settled by act of parliament. The
ecclesiastical courts are for the most part officered by laymen, whose
subordination to the archbishops and bishops is purely formal, and the
final court of appeal is the Judicial Committee of the Privy Council. In
like manner changes in the ecclesiastical law are made directly by
parliament in the ordinary course of legislation, and in point of fact a
very large portion of the existing ecclesiastical law consists of acts
of parliament.

The sources of the ecclesiastical law of England are thus described by
Dr. Richard Burn (_The Ecclesiastical Law_, 9th ed., 1842):--"The
ecclesiastical law of England is compounded of these four main
ingredients--the civil law, the canon law, the common law, and the
statute law. And from these, digested in their proper rank and
subordination, to draw out one uniform law of the church is the purport
of this book. When these laws do interfere and cross each other, the
order of preference is this:--'The civil law submitteth to the canon
law; both of these to the common law; and all three to the statute law.
So that from any one or more of these, without all of them together, or
from all of them together without attending to their comparative
obligation, it is not possible to exhibit any distinct prospect of the
English ecclesiastical constitution.' Under the head of statute law Burn
includes 'the Thirty-nine Articles of Religion, agreed upon in
Convocation in the year 1562; and in like manner the Rubric of the Book
of Common Prayer, which, being both of them established by Acts of
Parliament, are to be esteemed as part of the statute law.'"

The first principle of the ecclesiastical law in England is the
assertion of the supremacy of the crown, which in the present state of
the constitution means the same thing as the supremacy of parliament.
This principle has been maintained ever since the Reformation. Before
the Reformation the ecclesiastical supremacy of the pope was recognized,
with certain limitations, in England, and the Church itself had some
pretensions to ecclesiastical freedom. The freedom of the Church is, in
fact, one of the standing provisions of those charters on which the
English constitution was based. The first provision of Magna Carta is
_quod ecclesia Anglicana libera sit_. By the various enactments of the
period of the Reformation the whole constitutional position of the
Church, not merely with reference to the pope but with reference to the
state, was definitely fixed. The legislative power of convocation was
held to extend to the clergy only, and even to that extent required the
sanction and assent of the crown. The common law courts controlled the
jurisdiction of the ecclesiastical courts, claiming to have "the
exposition of such statutes or acts of parliament as concern either the
extent of the jurisdiction of these courts or the matters depending
before them. And therefore if these courts either refuse to allow these
acts of parliament, or expound them in any other sense than is truly and
properly the exposition of them, the king's great courts of common law
may prohibit and control them."

The design of constructing a code of ecclesiastical laws was entertained
during the period of the Reformation, but never carried into effect. It
is alluded to in various statutes of the reign of Henry VIII., who
obtained power to appoint a commission to examine the old ecclesiastical
laws, with a view of deciding which ought to be kept and which ought to
be abolished; and in the meantime it was enacted that "such canons,
institutions, ordinances, synodal or provincial or other ecclesiastical
laws or jurisdictions spiritual as be yet accustomed and used here in
the Church of England, which necessarily and conveniently are requisite
to be put in ure and execution for the time, not being repugnant,
contrarient, or derogatory to the laws or statutes of the realm, nor to
the prerogatives of the royal crown of the same, or any of them, shall
be occupied, exercised, and put in ure for the time with this realm" (35
Henry VIII. c. 16, 25 c. 19, 27 c. 8).

The work was actually undertaken and finished in the reign of Edward VI.
by a sub-committee of eight persons, under the name of the _Reformatio
legum ecclesiasticarum_, which, however, never obtained the royal
assent. Although the powers of the 25 Henry VIII. c. 1 were revived by
the 1 Elizabeth c. 1, the scheme was never executed, and the
ecclesiastical laws remained on the footing assigned to them in that
statute--so much of the old ecclesiastical laws might be used as had
been actually in use, and was not repugnant to the laws of the realm.

The statement is, indeed, made by Sir R. Phillimore (_Ecclesiastical
Law_, 2nd ed., 1895) that the "Church of England has at all times,
before and since the Reformation, claimed the right of an independent
Church in an independent kingdom, to be governed by the laws which she
has deemed it expedient to adopt." This position can only be accepted if
it is confined, as the authorities cited for it are confined, to the
resistance of interference from abroad. If it mean that the Church, as
distinguished from the kingdom, has claimed to be governed by laws of
her own making, all that can be said is that the claim has been
singularly unsuccessful. From the time of the Reformation no change has
been made in the law of the Church which has not been made by the king
and parliament, sometimes indirectly, as by confirming the resolutions
of convocation, but for the most part by statute. The list of statutes
cited in Sir R. Phillimore's _Ecclesiastical Law_ fills eleven pages. It
is only by a kind of legal fiction akin to the "collegial" theory
mentioned above, that the Church can be said to have deemed it expedient
to adopt these laws.

The terms on which the Church Establishment of Ireland was abolished, by
the Irish Council Act of 1869, may be mentioned. By sect. 20 the present
ecclesiastical law was made binding on the members for the time being of
the Church, "as if they had mutually contracted and agreed to abide by
and observe the same"; and by section 21 it was enacted that the
ecclesiastical courts should cease after the 1st of January 1871, and
that the ecclesiastical laws of Ireland, except so far as relates to
matrimonial causes and matters, should cease to exist as law. (See also
ENGLAND, CHURCH OF; ESTABLISHMENT; &c.)

  AUTHORITIES.--The number of works on ecclesiastical law is very great,
  and it must suffice here to mention a few of the more conspicuous
  modern ones: Ferdinand Walter, _Lehrbuch des Kirchenrechts aller
  christlichen Konfessionen_ (14th ed., Bonn, 1871); G. Phillips,
  _Kirchenrecht_, Bde. i.-vii. (Regensburg, 1845-1872) incomplete; the
  text-book by Cardinal Hergenröther (q.v.); P. Hinschius, _Kirchenrecht
  der Katholiken und Protestanten in Deutschland_, 6 Bde. (Berlin, 1869
  sqq.), only the Catholic part, a masterly and detailed survey of the
  ecclesiastical law, finished; Sir Robert Phillimore, _Eccl. Law of the
  Church of England_ (2nd ed., edited by Sir Walter Phillimore, 2 vols.,
  London, 1895). For further references see CANON LAW, and the article
  "Kirchenrecht" in Herzog-Hauck, _Realencyklopädie_ (ed. Leipzig,
  1901).



ECCLESIASTICUS (abbreviated to _Ecclus._), the alternative title given
in the English Bible to the apocryphal book otherwise called "The Wisdom
of Jesus the son of Sirach." The Latin word _ecclesiasticus_ is,
properly speaking, not a name, but an epithet meaning "churchly," so
that it would serve as a designation of any book which was read in
church or received ecclesiastical sanction, but in practice
Ecclesiasticus has become a by-name for the Wisdom of Sirach. The true
name of the book appears in the authorities in a variety of forms, the
variation affecting both the author's name and the description of his
book. The writer's full name is given in 1. 27 (Heb. text) as "Simeon
the son of Jeshua (i.e. Jesus) the son of Eleazar the son of Sira." In
the Greek text this name appears as "Jesus son of Sirach Eleazar"
(probably a corruption of the Hebrew reading), and the epithet "of
Jerusalem" is added, the translator himself being resident in Egypt. The
whole name is shortened sometimes to "Son of Sira," _Ben Sira_ in
Hebrew, _Bar Sira_ in Aramaic, and sometimes (as in the title prefixed
in the Greek cod. B) to _Sirach_. The work is variously described as the
_Words_ (Heb. text), the _Book_ (Talmud), the _Proverbs_ (Jerome), or
the _Wisdom_ of the son of Sira (or Sirach).

Of the date of the book we have only one certain indication. It was
translated by a person who says that he "came into Egypt in the 38th
year of Euergetes the king" (Ptolemy VII.), i.e. in 132 B.C., and that
he executed the work some time later. The translator believed that the
writer of the original was his own grandfather (or ancestor, [Greek:
pappos]). It is therefore reasonable to suppose that the book was
composed not later than the first half of the 2nd century B.C., or (if
we give the looser meaning to [Greek: pappos]) even before the beginning
of the century. Arguments for a pre-Maccabean date may be derived (a)
from the fact that the book contains apparently no reference to the
Maccabean struggles, (b) from the eulogy of the priestly house of Zadok
which fell into disrepute during these wars for independence.

In the Jewish Church Ecclesiasticus hovered on the border of the canon;
in the Christian Church it crossed and recrossed the border. The book
contains much which attracted and also much which repelled Jewish
feeling, and it appears that it was necessary to pronounce against its
canonicity. In the Talmud (Sanhedrin 100 b) Rabbi Joseph says that it is
forbidden to read (i.e. in the synagogue) the book of ben Sira, and
further that "if our masters had not hidden the book (i.e. declared it
uncanonical), we might interpret the good things which are in it"
(Schechter, _J. Q. Review_, iii. 691-692). In the Christian Church it
was largely used by Clement of Alexandria (c. A.D. 200) and by St
Augustine. The lists of the Hebrew canon, however, given by Melito (c.
A.D. 180) and by Origen (c. A.D. 230) rightly exclude Ecclesiasticus,
and Jerome (c. A.D. 390-400) writes: "Let the Church read these two
volumes (Wisdom of Solomon and Ecclesiasticus) for the instruction of
the people, not for establishing the authority of the dogmas of the
Church" (_Praefatio in libros Salomonis_). In the chief MS. of the
Septuagint, cod. B, Ecclesiasticus comes between Wisdom and Esther, no
distinction being drawn between canonical and uncanonical. In the
Vulgate it immediately precedes Isaiah. The council of Trent declared
this book and the rest of the books reckoned in the Thirty-nine Articles
as apocryphal to be canonical.

The text of the book raises intricate problems which are still far from
solution. The original Hebrew (rediscovered in fragments and published
between 1896 and 1900) has come down to us in a mutilated and corrupt
form. The beginning as far as iii. 7 is lost. There is a gap from xvi.
26 to xxx. 11. There are marginal readings which show that two different
recensions existed once in Hebrew. The Greek version exists in two
forms--(a) that preserved in cod. B and in the other uncial MSS., (b)
that preserved in the cursive codex 248 (Holmes and Parsons). The former
has a somewhat briefer text, the latter agrees more closely with the
Hebrew text. The majority of Greek cursives agree generally with the
Latin Vulgate, and offer the fuller text in a corrupt form. The Syriac
(Peshitta) version is paraphrastic, but on the whole it follows the
Hebrew text. Owing to the mutilation of the Hebrew by the accidents of
time the Greek version retains its place as the chief authority for the
text, and references by chapter and verse are usually made to it.

Bickell and D.S. Margoliouth have supposed that the Hebrew text
preserved in the fragments is not original, but a retranslation from the
Greek or the Syriac or both. This view has not commended itself to the
majority of scholars, but there is at least a residuum of truth in it.
The Hebrew text, as we have it, has a history of progressive corruption
behind it, and its readings can often be emended from the Septuagint,
e.g. xxxvii. 11 (read [Hebrew: umira] for the meaningless [Hebrew:
umerer]). The Hebrew marginal readings occasionally seem to be
translations from the Greek or Syriac, e.g. xxxviii. 4 ([Hebrew: bara
shamaym] for [Greek: ektisen pharmaka]). More frequently, however,
strange readings of the Greek and Syriac are to be explained as
corruptions of our present Hebrew. Substantially our Hebrew must be
pronounced original.

The restoration of a satisfactory text is beyond our hopes. Even before
the Christian era the book existed in two recensions, for we cannot
doubt, after reading the Greek translator's preface, that the translator
amplified and paraphrased the text before him. It is probable that at
least one considerable omission must be laid to his charge, for the hymn
preserved in the Hebrew text after ch. li. 12 is almost certainly
original. Ancient translators allowed themselves much liberty in their
work, and Ecclesiasticus possessed no reputation for canonicity in the
2nd century B.C. to serve as a protection for its text. Much, however,
may be done towards improving two of the recensions which now lie before
us. The incomplete Hebrew text exists in four different MSS., and the
study of the peculiarities of these had already proved fruitful. The
Syriac text, made without doubt from the Hebrew, though often
paraphrastic is often suggestive. The Greek translation, made within a
century or half-century of the writing of the book, must possess great
value for the criticism of the Hebrew text. The work of restoring true
Hebrew readings may proceed with more confidence now that we have
considerable portions of the Hebrew text to serve as a model. For the
restoration of the Greek text we have, besides many Greek MSS., uncial
and cursive, the old Latin, the Syro-Hexaplar, the Armenian, Sahidic and
Ethiopic versions, as well as a considerable number of quotations in the
Greek and Latin Fathers. Each of the two recensions of the Greek must,
however, be separately studied, before any restoration of the original
Greek text can be attempted.

The uncertainty of the text has affected both English versions
unfavourably. The Authorized Version, following the corrupt cursives, is
often wrong. The Revised Version, on the other hand, in following the
uncial MSS. sometimes departs from the Hebrew, while the Authorized
Version with the cursives agrees with it. Thus the Revised Version (with
codd. [Hebrew: alef]*, A, B, C) omits the whole of iii. 19, which the
Authorized Version retains, but for the clause, "Mysteries are revealed
unto the meek," the Authorized Version has the support of the Hebrew,
Syriac and cod. 248. Sometimes both versions go astray in places in
which the Hebrew text recommends itself as original by its vigour; e.g.
in vii. 26, where the Hebrew is,

  Hast thou a wife? abominate her not.
  Hast thou a hated wife? trust not in her.

Again in ch. xxxviii. the Hebrew text in at least two interesting
passages shows its superiority over the text which underlies both
English versions.

                _Hebrew._                _Revised Version (similarly
                                             Authorized Version)._

  ver. 1.  Acquaint thyself with a       Honour a physician according
           physician before thou have    to thy need of him with the
           need of him.                  honours due unto him.

  ver. 15. He that sinneth against his   He that sinneth before his
           Maker will behave himself     Maker, let him fall into the
           proudly against a physician.  hands of the physician.

In the second instance, while the Hebrew says that the man who rebels
against his Heavenly Benefactor will _a fortiori_ rebel against a human
benefactor, the Greek text gives a cynical turn to the verse, "Let the
man who rebels against his true benefactor be punished through the
tender mercies of a quack." The Hebrew text is probably superior also in
xliv. 1, the opening words of the eulogy of the Fathers: "Let me now
praise favoured men," i.e. men in whom God's grace was shown. The Hebrew
phrase is "men of grace," as in v. 10. The Greek text of v. 1, "famous
men," seems to be nothing but a loose paraphrase, suggested by v. 2,
"The Lord manifested in them great glory."

In character and contents Ecclesiasticus resembles the book of Proverbs.
It consists mainly of maxims which may be described in turn as moral,
utilitarian and secular. Occasionally the author attacks prevalent
religious opinions, e.g. the denial of free-will (xv. 11-20), or the
assertion of God's indifference towards men's actions (xxxv. 12-19).
Occasionally, again, Ben Sira touches the highest themes, and speaks of
the nature of God: "He is All" (xliii. 27); "He is One from everlasting"
(xlii. 21, Heb. text); "The mercy of the Lord is upon all flesh" (xviii.
13). Though the book is imitative and secondary in character it contains
several passages of force and beauty, e.g. ch. ii. (how to fear the
Lord); xv. 11-20 (on free-will); xxiv. 1-22 (the song of wisdom); xlii.
15-25 (praise of the works of the Lord); xliv. 1-15 (the well-known
praise of famous men). Many detached sayings scattered throughout the
book show a depth of insight, or a practical shrewdness, or again a
power of concise speech, which stamps them on the memory. A few examples
out of many may be cited. "Call no man blessed before his death" (xi.
28); "He that toucheth pitch shall be defiled" (xiii. 1); "He hath not
given any man licence to sin" (xv. 20); "Man cherisheth anger against
man; and doth he seek healing from the Lord?" (xxviii. 3); "Mercy is
seasonable ... as clouds of rain" (xxxv. 20); "All things are double one
against another: and he hath made nothing imperfect" (xlii. 24, the
motto of Butler's _Analogy_); "Work your work before the time cometh,
and in his time he will give you your reward" (li. 30). In spite,
however, of the words just quoted it cannot be said that Ben Sira
preaches a hopeful religion. Though he prays, "Renew thy signs, and
repeat thy wonders ... Fill Sion with thy majesty and thy Temple with
thy glory" (xxxvi. 6, 14 [19], Heb. text), he does not look for a
Messiah. Of the resurrection of the dead or of the immortality of the
soul there is no word, not even in xli. 1-4, where the author exhorts
men not to fear death. Like the Psalmist (Ps. lxxxviii. 10, 11) he asks,
"Who shall give praise to the Most High in the grave?" In his maxims of
life he shows a somewhat frigid and narrow mind. He is a pessimist as
regards women; "From a woman was the beginning of sin; and because of
her we all die" (xxv. 24). He does not believe in home-spun wisdom; "How
shall he become wise that holdeth the plough?" (xxxviii. 25). Artificers
are not expected to pray like the wise man; "In the handywork of their
craft is their prayer" (v. 34). Merchants are expected to cheat; "Sin
will thrust itself in between buying and selling" (xxvii. 2).

  BIBLIOGRAPHY.--The literature of Ecclesiaticus has grown very
  considerably since the discovery of the first Hebrew fragment in 1896.
  A useful summary of it is found at the end of Israel Levi's article,
  "Sirach," in the _Jewish Encyclopedia_. Eberhard Nestle's article in
  Hastings's _Dictionary of the Bible_ is important for its
  bibliographical information as well as in other respects. A complete
  edition of the Hebrew fragments in collotype facsimile was published
  jointly by the Oxford and Cambridge Presses in 1901. J.H.A. Hart's
  edition of cod. 248 throws much light on some of the problems of this
  book. It contains a fresh collation of all the chief authorities
  (Heb., Syr., Syr.-Hex., Lat. and Gr.) for the text, together with a
  complete textual commentary.

  The account given in the _Synopsis_ attributed to Athanasius (Migne,
  _P.G._, iv. 375-384) has an interest of its own. The beginning is
  given in the Authorized Version as "A prologue made by an uncertain
  author."     (W. E. B.)



ECGBERT, or ECGBERHT (d. 839), king of the West Saxons, succeeded to the
throne in 802 on the death of Beorhtric. It is said that at an earlier
period in his life he had been driven out for three years by Offa and
Beorhtric. The accession of Ecgbert seems to have brought about an
invasion by Æthelmund, earl of the Hwicce, who was defeated by Weoxtan,
earl of Wiltshire. In 815 Ecgbert ravaged the whole of the territories
of the West Welsh, which probably at this time did not include much more
than Cornwall. The next important occurrence in the reign was the defeat
of Beornwulf of Mercia at a place called Ellandun in 825. After this
victory Kent, Surrey, Sussex and Essex submitted to Wessex; while the
East Anglians, who slew Beornwulf shortly afterwards, acknowledged
Ecgbert as overlord. In 829 the king conquered Mercia, and Northumbria
accepted him as overlord. In 830 he led a successful expedition against
the Welsh. In 836 he was defeated by the Danes, but in 838 he won a
battle against them and their allies the West Welsh at Hingston Down in
Cornwall. Ecgbert died in 839, after a reign of thirty-seven years, and
was succeeded by his son Æthelwulf. A somewhat difficult question has
arisen as to the parentage of Ecgbert. Under the year 825 the Chronicle
states that in his eastern conquests Ecgbert recovered what had been
the rightful property of his kin. The father of Ecgbert was called
Ealhmund, and we find an Ealhmund, king in Kent, mentioned in a charter
dated 784, who is identified with Ecgbert's father in a late addition to
the Chronicle under the date 784. It is possible, however, that the
Chronicle in 825 refers to some claim through Ine of Wessex from whose
brother Ingeld Ecgbert was descended.

  See _Anglo-Saxon Chronicle_, edited by Earle and Plummer (Oxford,
  1899); W. de G. Birch, _Cartularium Saxonicum_ (London, 1885-1893).
  Also a paper by Sir H.H. Howorth in _Numismatic Chronicle_, third
  series, vol. xx. pp. 66-87 (reprinted separately, London, 1900), where
  attention is called to the peculiar dating of several of Ecgbert's
  charters, and the view is put forward that he remained abroad
  considerably later than the date given by the Chronicle for his
  accession. On the other hand a charter in Birch, _Cart. Sax._,
  purporting to date from 799, contains the curious statement that peace
  was made between Coenwulf and Ecgbert in that year.



ECGBERT, or ECGBERHT (d. 766), archbishop of York, was made bishop of
that see in 734 by Ceolwulf, king of Northumbria, succeeding Wilfrid II.
on the latter's resignation. The pall was sent him in 735 and he became
the first northern archbis