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Title: Philosophy in Sport Made Science in Earnest - Being an Attempt to Illustrate the First Principles of - Natural Philosophy by the Aid of Popular Toys and Sports
Author: Paris, John Ayrton
Language: English
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*** Start of this LibraryBlog Digital Book "Philosophy in Sport Made Science in Earnest - Being an Attempt to Illustrate the First Principles of - Natural Philosophy by the Aid of Popular Toys and Sports" ***
PHILOSOPHY IN SPORT
MADE
SCIENCE IN EARNEST;
BEING
AN ATTEMPT TO ILLUSTRATE THE FIRST PRINCIPLES
OF NATURAL PHILOSOPHY
BY THE AID OF
POPULAR TOYS AND SPORTS.
[Illustration: Printer’s logo]
FOURTH EDITION,
WITH CONSIDERABLE ADDITIONS.
LONDON:
HARVEY AND DARTON, GRACECHURCH-STREET;
AND HIGHLEY, FLEET-STREET.
1839.
------------------------------------------------------------------------
TO
MISS MARIA EDGEWORTH.
MADAM,
To whom can a work which professes to blend amusement with instruction,
be dedicated with so much propriety, as to one, whose numerous writings
have satisfactorily demonstrated the practicability and value of such a
union;--to one, who has stripped Romance of her meretricious trappings,
and converted her theatre into a temple worthy of Minerva? Justly has
it been observed, that to the magic pens of Madame D’Arblay and
yourself we are indebted for having the Novel restored to its
consequence, and, therefore, to its usefulness; and I may be allowed to
add, that your Harry and Lucy has shown how profitably, and agreeably,
the machinery of fiction may be worked for the dissemination of truth.
That a life which has been so honourable to yourself, and so
serviceable to the commonwealth, may be long extended, and deservedly
enjoyed, is the fervent wish of
THE AUTHOR.
_London,
February 1839._
------------------------------------------------------------------------
TO THE READER.
--------------
Tell me, gentle Reader, whether thou hast not heard of the box of
Pandora, which was no sooner opened by the unhappy Epimetheus, than it
gave flight to a troop of malevolent spirits, which have ever since
tormented the human race.--Behold!--I here present you with a magic
casket, containing a GENIUS alone capable of counteracting their
direful spells. Thou mayest, perhaps, say that its aspect but ill
accords with the richness of its promised treasure; so appeared the
copper vessel found by the fisherman, as related in the Arabian tale;
but, remember, that no sooner had he broken its mystic seal, than the
imprisoned genius spread itself over the ocean and raised its giant
limbs above the clouds. But this was an evil and treacherous spirit;
mine is as benevolent as he is mighty, and seeks communion with our
race for no other object than to render mortals virtuous and happy. To
be plain, for you must already, my young friends, have unriddled my
allegory, his name is PHILOSOPHY.
In your progress through life, be not so vain as to believe that you
will escape the evils with which its path is beset. Arm yourselves,
therefore, with the talisman that can, at once, deprive adversity of
its sting, and prosperity of its dangers; for such, believe me, is the
rare privilege of philosophy.
I must now take leave of you, for a short time, in order that I may
address a few words to your parents and preceptors; but, as I have no
plot to abridge your liberties, or lengthen your hours of study, you
may listen to my address without alarm, and to my plan without
suspicion. Imagine not, however, that I shall recommend the dismissal
of the cane, or the whip; on the contrary, I shall insist upon them as
necessary and indispensable instruments for the accomplishment of my
design. But the method of applying them will be changed; with the one I
shall construct the bow of the kite, with the other I shall spin the
top.
The object of the present work is to inculcate that early love of
science which can never be derived from the sterner productions. Youth
is naturally addicted to amusement, and in this item his expenditure
too often exceeds his allotted income. I have, therefore, taken the
liberty to draw a draft upon Philosophy, with the full assurance that
it will be gratefully repaid, with compound interest, ten years after
date. But to be serious; those who superintend the education of youth
should be apprised of the great importance of the first impressions.
Rousseau has said, that the seeds of future vices or virtues are more
frequently sown by the mother than the tutor; thereby intimating, that
the characters of men are often determined by the earliest impressions;
and, of so much moment did Quintillian regard this truth, that he
recommends to us the example of Philip, who did not suffer any other
than Aristotle to teach Alexander to read. In like manner those who do
not commence their study of nature at an early season, will afterwards
have many unnecessary obstacles to encounter. The difficulty of
comprehending the principles of Natural Philosophy frequently arises
from their being at variance with those false ideas which early
associations have impressed upon the mind; the first years of study
are, therefore, expended in _un_learning, and in clearing away the
weeds, which would never have taken root in a properly cultivated soil.
Writers on practical education have repeatedly advocated the advantages
of the plan I am so anxious to enforce; but, strange to say, it is only
within a few years that any works have appeared at all calculated to
afford the necessary assistance. In short, previous to the labours of
Mrs. Marcet and Miss Edgeworth, the productions published for the
purpose of juvenile instruction may be justly charged with the grossest
errors; and must have proved as destructive to the mind of the young
reader, as the book presented by the physician Douban is said to have
been to the Grecian king, who, as the Arabian tale relates, imbibed
fresh poison as he turned over each leaf, until he fell lifeless in the
presence of his courtiers; or, to give another illustration, as
mischievous as the magic volume of Michael Scott, which, as Dempster
informs us, could not be opened without the danger of invoking some
malignant fiend by the operation. How infinitely superior in execution
and purpose are the juvenile works of the present century!--to borrow a
metaphor from Coleridge, they may be truly said to resemble a
collection of mirrors set in the same frame, each having its own focus
of knowledge, yet all capable of converging to one point.
Allow me, friendly Reader, before I conclude my address, to say a few
words upon the plan and execution of the work before you. It is not
intended to supersede or clash with any of the elementary treatises to
which I have alluded; indeed its plan is so peculiar, that I apprehend
such a charge cannot be brought against it. The author originally
composed it for the exclusive use of his children, and would certainly
never have consigned it to the press, but at the earnest solicitations
of those friends upon whose judgment he places the utmost reliance. Let
this be received as an answer to those, who, believing that they can
recognise the writer, may be induced to exclaim with Menedemus in
Terence,--“_Tantumne est ab re tuâ otii tibi aliena ut cures, eaque
nihil quæ ad te attinent?_” [1]
It is scarcely necessary to offer any apology for the conversational
plan of instruction; the success of Mrs. Marcet’s dialogues has placed
its value beyond dispute. It may, however, be observed, that this
species of composition may be executed in two different ways, either as
direct conversation, where none but the speakers appear, which is the
method used by Plato; or as the recital of a conversation, where the
author himself appears, and gives an account of what passed in
discourse, which is the plan generally adopted by Cicero. The reader is
aware, that Mrs. Marcet, in her “Conversations on Philosophy,” has
adopted the former, while Miss Edgeworth, in her “Harry and Lucy,” has
preferred the latter method. In composing the present work I have
followed the plan of the last-mentioned authoress. Its advantages over
the more direct conversational style appear to consist in allowing
occasional remarks, which come more aptly from the author than from any
of the characters engaged in the dialogue.
If scientific dialogues are less popular in our times than they were in
ancient days, it must be attributed to the frigid and insipid manner in
which they have too frequently been executed; if we except the mere
external forms of conversation, and that one character is made to
speak, and the other to answer, they are altogether the same as if the
author himself spoke throughout the whole, instead of amusing with a
varied style of conversation, and with a display of consistent and
well-supported characters. The introduction of a person of humour, to
enliven the discourse, is sanctioned by the highest authority. Cæsar is
thus introduced by Cicero, and Cynthio by Addison. In the introduction
of Mr. Twaddleton and Major Snapwell, I am well aware of the criticisms
to which I am exposed; I have exercised my fancy with a freedom and
latitude, for which, probably, there is not any precedent in a
scientific work. I have even ventured so far to deviate from the beaten
track as to skirmish upon the frontiers of the Novelist, and to bring
off captive some of the artillery of Romance; but if, by so doing, I
have enhanced the interest of my work, and furthered the accomplishment
of its object, let me intreat that mere novelty may not be urged to its
disparagement. The antiquarian Vicar, however, will, I trust, meet with
cordial reception from the classical student. As to Ned Hopkins,
although he may not bear a comparison with William Summers, the fool of
Henry VIII.--or with Richard Tarlton, who “_undumpished_ Queen
Elizabeth at his pleasure;” or with Archibald Armstrong (vulgo
_Archee_) Jester to Charles,--yet I will maintain, in spite of the
Vicar’s censure, that he is a right merry fellow, and to the Major, and
consequently to our history, a most important accessary.
If it be argued that several of my comic representations are
calculated, like seasoning, to stimulate the palate of the
novel-reader, rather than to nourish the minds of the younger class,
for whom the work was written, I might, were I so disposed, plead
common usage; for does not the director of a juvenile fête courteously
introduce a few piquant dishes, for the entertainment of those elder
personages who may attend in the character of a chaperone? You surely
could not deny me the full benefit of such a precedent; and so, Gentle
Reader, I bid thee--Farewell!
-----
Footnote 1:
“Have you such leisure from your own affairs
To think of those that don’t concern you?”
------------------------------------------------------------------------
CONTENTS.
* * * * *
CHAPTER I. Page 1
Tom Seymour’s arrival from school--Description of Overton Lodge--The
Horologe of Flora--A geological temple--A sketch of the person and
character of the Reverend Peter Twaddleton--Mr. Seymour engages to
furnish his son with any toy, the philosophy of which he is able to
explain--Mr. Twaddleton’s arrival, and reception--His remonstrances
against the diffusion of science amongst the village mechanics--A
dialogue between Mr. Seymour and the Vicar, which some will dislike,
many approve of, and all laugh at--The plan of teaching philosophy by
the aid of toys developed and discussed--Mr. Twaddleton’s objections
answered--He relents, and engages to furnish an antiquarian history of
the various toys and sports
CHAPTER II. Page 25
On gravitation--Weight--The velocity of falling bodies--At what
altitude a body would lose its gravity--The Tower of Babel--The known
velocity of sound affords the means of calculating distances--An
excursion to Overton well--An experiment to ascertain its depth--A
visit to the vicarage--The magic gallery--Return to the lodge
CHAPTER III. Page 48
Motion--absolute and relative--Uniform, accelerated, and retarded
velocity--The times of ascent and descent are equal--Vis
inertiæ--Friction--Action and reaction are equal and in opposite
directions--Momentum defined and explained--The three great laws of
motion
CHAPTER IV. Page 65
A sad accident turned to a good account--One example worth a hundred
precepts--The centres of magnitude and gravity--The point of
suspension--The line of direction--The stability of bodies, and upon
what it depends--Method of finding the centre of gravity of a body--The
art of the balancer explained and illustrated--Various balancing toys
CHAPTER V. Page 85
The Chinese tumblers, illustrating the joint effects of change in the
centre of gravity of a body, and of momentum--Mr. Twaddleton’s
arrival after a series of adventures--The dancing balls--The
pea-shooter--A figure that dances on a fountain--The flying
witch--Elasticity--Springs--The game of “Ricochet,” or duck and
drake--The rebounding ball--Animals that leap by means of an elastic
apparatus--A new species of puffing, by which the Vicar is made to
change countenance
CHAPTER VI. Page 102
The arrival of Major Snapwell, and the bustle it occasioned--The
Vicar’s interview with the stranger--A curious discussion--A word or
two addressed to fox-hunters--Verbal corruptions--Some geometrical
definitions--An enigma
CHAPTER VII. Page 117
Compound forces--The composition and resolution of motion--Rotatory
motion--The revolving watch-glass--The sling--The centrifugal and
centripetal forces--Theory of projectiles--A geological conversation
between Mr. Seymour and the Vicar
CHAPTER VIII. Page 136
The subject of rotatory motion continued--A ball, by having a peculiar
spinning motion imparted to it, may be made to stop short, or to
retrograde, though it meets not with any apparent obstacle--The
rectilinear path of a spherical body influenced by its rotatory
motion--Bilboquet, or cup and ball--The joint forces which enable the
balancer to throw up and catch his balls on the full gallop--The
hoop--The centre of percussion--The whip and peg-top--Historical
notices--The power by which the top is enabled to sustain its vertical
position during the act of spinning--The sleeping of the top
explained--The force which enables it to rise from an oblique into a
vertical position--Its gyration
CHAPTER IX. Page 151
Trap and ball--Gifts from the Vicar--An antiquarian history of the
ball--The see-saw--The mechanical powers--The swing--The doctrine of
oscillation--Galileo’s discovery--The pendulum--An interesting
letter--Mr. Seymour and the Vicar visit Major Snapwell
CHAPTER X. Page 167
Marbles--Antiquity of the game--Method of manufacturing
them--Ring-taw--Mr. Seymour, the Vicar, and Tom, enter the lists--The
defeat of the two former combatants; the triumph of the latter--A
philosophical explanation of the several movements--The subject of
reflected motion illustrated--The Vicar’s apology, of which many grave
personages will approve
CHAPTER XI. Page 180
Mr. Seymour and his family visit the Major at Osterley Park--A
controversy between the Vicar and the Major--The Sucker--Cohesive
attraction--Pressure of the atmosphere--Meaning of the term
suction--Certain animals attach themselves to rocks by a contrivance
analogous to the sucker--The Limpet--The Walrus--Locomotive organs of
the house-fly--A terrible accident--A scene in the village, in which
Dr. Doseall figures as a principal performer--The Vicar’s sensible
remonstrance--The density of the atmosphere at different
altitudes--Inelasticity of water--Bottle-imps--The Barometer--The
pop-gun--The air-gun--An antiquarian discussion, in which the Vicar and
Major Snapwell greatly distinguish themselves
CHAPTER XII. Page 202
The soap-bubble--The squirt--The bellows; an explanation of their
several parts--By whom the instrument was invented--The sucking and
lifting, or common pump
CHAPTER XIII. Page 215
The kite--Its construction--The tail--An author’s meditations among the
catacombs of Paternoster-row--Works in their winding sheets--How Mr.
Seymour strung puns as he strung the kite’s tail--The Vicar’s
dismay--The weather, with the hopes and fears which it alternately
inspired--Kites constructed in various shapes--The figure usually
adopted to be preferred--The flight of the kite--A philosophical
disquisition upon the forces by which its ascent is accomplished--The
tail--A discourse on the theory of flying--The structure and action of
the wings of birds--A series of kites on one string--A kite
carriage--The messenger--The causes and velocity of wind explained
CHAPTER XIV. Page 247
A short discourse--The shuttlecock--The solution of two problems
connected with its flight--The windmill--The smoke-jack--A toy
constructed on the same principle--The bow and arrow--Archery--The
arrival of Isabella Villers
CHAPTER XV. Page 262
A curious dialogue between the Vicar and Miss Villers--An enigma--The
riddles of Samson and Cleobulus--Sound--How propagated by aërial
vibration--Music--A learned discussion touching the superior powers of
ancient music--The magic of music, a game which the author believes is
here described for the first time--Adventures by moonlight--Spirits of
the valley
CHAPTER XVI. Page 291
Origin of the crescent as the Turkish ensign--Apparitions dispelled by
philosophy--Fairy rings--Musical instruments classed under three
divisions--Mixed instruments--Theory of wind instruments--The Jew’s
harp--The statue of Memnon--An interesting experiment--The flute--The
whiz-gig, &c.--Echoes--The whispering gallery in the dome of St.
Paul’s--The speaking trumpet--The invisible girl--Other acoustic
amusements--Creaking shoes--Haunted rooms
CHAPTER XVII. Page 319
An interesting communication, from which the reader may learn that the
most important events are not those which absorb the greatest portion
of time in their recital--Major Snapwell communicates to Mr. Seymour
and the Vicar, his determination to celebrate the marriage of his
nephew by a fête at Osterley Park--An antiquarian discussion of grave
importance--An interview with Ned Hopkins, during which the wit
displayed both cunning and humour--The Thaumatrope--Its improved
construction--Philosophy of its action--Another optical toy--The nature
of optical spectra illustrated and explained--The spectral cross of
Constantine
CHAPTER XVIII. Page 337
The Thaumatrope--A great improvement effected in its
construction--Another toy upon the same optical principle
CHAPTER XIX. Page 364
Preparations for the approaching fête--The procession of the bridal
party to Osterley Park--The Major and his visitors superintend the
arrangements in the meadow--The curious discussion which took place on
that occasion--The origin of the swing--Merry-andrews--Trajetours,
&c.--The dinner at the hall--The learned controversy which was
maintained with respect to the game of Chess
CHAPTER XX. Page 383
The arrival of the populace at Osterley Park--The commencement of
the festivities--Dancing on the tight and slack
rope--Balancing--Conjuring--Optical illusions--Various
games--Penthalum--The banquet--Grand display of
fire-works--Conclusion
APPENDIX--Additional Notes Page 407
------------------------------------------------------------------------
PHILOSOPHY IN SPORT.
CHAPTER I.
_Tom Seymour’s arrival from school.--Description of Overton
Lodge.--The Horologe of Flora.--A geological temple.--A
sketch of the person and character of the Reverend Peter
Twaddleton.--Mr. Seymour engages to furnish his son with any
toy, the philosophy of which he is able to explain.--Mr.
Twaddleton’s arrival and reception.--His remonstrances
against the diffusion of science amongst the village
mechanics.--A dialogue between Mr. Seymour and the vicar,
which some will dislike, many approve of, and all laugh
at.--The plan of teaching philosophy by the aid of toys
developed and discussed.--Mr. Twaddleton’s objections
answered.--He relents, and engages to furnish an antiquarian
history of the various toys and sports._
The summer recess of Mr. Pearson’s school was not more anxiously
anticipated by the scholars than it was by the numerous family of
Seymour, who, at the commencement of the year, had parted from a
beloved son and brother for the first time. As the season of relaxation
approached, so did the inmates of Overton Lodge (for such was the name
of Mr. Seymour’s seat) betray increasing impatience for its arrival.
The three elder sisters, Louisa, Fanny, and Rosa, had been engaged for
several days in arranging the little study which their brother Tom had
usually occupied. His books were carefully replaced on their shelves,
and bunches of roses and jasmines, which the affectionate girls had
culled from the finest trees in the garden, were tastefully dispersed
through the apartment; the festoons of blue ribbons, with which they
were entwined, at once announced themselves as the work of graceful
hands, impelled by light hearts; and every flower might be said to
reflect from its glowing petals the smiles with which it had been
collected and arranged. At length the happy day arrived; a post-chaise
drew up to the front gate, and Tom was once again folded in the arms of
his affectionate and delighted parents. The little group surrounded
their beloved brother, and welcomed his return with all the warmth and
artlessness of juvenile sincerity. “Well,” said Mr. Seymour, “if the
improvement of your mind corresponds with that of your looks, I shall
indeed have reason to congratulate myself upon the choice of your
school. But have you brought me any letter from Mr. Pearson?” “I have,”
replied Tom, who presented his father with a note from his master, in
which he had commented, in high terms of commendation, not only upon
Tom’s general conduct, but upon the rapid progress which he had made in
his classical studies.
“My dearest boy,” exclaimed the delighted father, “I am more than
repaid for the many anxious moments which I have passed on your
account. I find that your conduct has given the highest satisfaction to
your master; and that your good-nature, generosity, and, above all,
your strict adherence to truth, have ensured the love and esteem of
your school-fellows.” This gratifying report brought tears of joy into
the eyes of Mrs. Seymour; Tom’s cheek glowed with the feeling of
conscious merit; and the sisters interchanged looks of mutual
satisfaction. Can there be an incentive to industry and virtuous
conduct so powerful as the exhilarating smiles of approbation which the
school-boy receives from an affectionate parent? Tom would not have
exchanged his feelings for all the world, and he internally vowed that
he would never deviate from a course that had been productive of so
much happiness.
“But come,” exclaimed Mr. Seymour, “let us all retire into the library.
I am sure that our dear fellow will be glad of some refreshment after
his journey.”
We shall here leave the family circle to the undisturbed enjoyment of
their domestic banquet, and invite the reader to accompany us in a
stroll about the grounds of this beautiful and secluded retreat.
We are amongst those who believe that the habits and character of a
family may be as easily discovered from the rural taste displayed in
the grounds which surround their habitation, as by any examination of
the prominences on their heads, or of the lineaments in their faces.
How vividly is the decline of an ancient race depicted by the chilling
desolation which reigns around the mansion, and by the rank weed which
insolently triumphs over its fading splendour; and how equally
expressive of the peaceful and contented industry of the thriving
cottager, is the well cultivated patch which adjoins the humble
dwelling, around whose rustic porch the luxuriant lilac clusters, or
the aspiring woodbine twines its green tendrils and sweetly-scented
blossoms! In like manner did the elegantly disposed grounds of Overton
Lodge at once announce the classic taste and fostering presence of a
refined and highly cultivated family.
The house, which was in the Ionic style of architecture, was situated
on the declivity of a hill, so that the verdant lawn which was spread
before its southern front, after retaining its level for a short
distance, gently sloped to the vale beneath, and was terminated by a
luxuriant shrubbery, over which the eye commanded a range of fair
enclosure, beautified by an irregularly undulating surface, and
interspersed with rich masses of wood. The uniformity of the lawn was
broken by occasional clumps of flowering shrubs, so artfully selected
and arranged, as to afford all the varied charms of contrast; while,
here and there, a lofty elm flung its gigantic arms over the sward
beneath, and cast a deep shade, which enabled the inhabitants of the
Lodge to enjoy the air, even during the heat of a meridian sun. The
shrubbery, which occupied a considerable portion of the valley,
stretched for some distance up the western part of the hill; and, could
Shenstone have wandered through its winding paths and deep recesses,
his favourite Leasowes might have suffered from a comparison. Here were
mingled shrubs of every varied dye; the elegant foliage of white and
scarlet acacias was blended with the dark-green-leaved chestnut; and
the stately branches of the oak were relieved by the gracefully
pendulous boughs of the beech. At irregular intervals, the paths
expanded into verdant glades, in each of which the bust of some
departed poet or philosopher announced the genius to which they were
severally consecrated. From a description of one or two of these
sequestered spots, the reader will readily conceive the taste displayed
in those upon which our limits will not allow us to dwell.
After winding, for some distance, through a path so closely interwoven
with shrubs and trees, that scarcely a sunbeam could struggle through
the foliage, a gleam of light burst through the gloom, and displayed a
beautiful marble figure, which had been executed by a Roman artist,
representing Flora in the act of being attired by Spring. It was placed
in the centre of the expanse formed by the retiring trees, and at its
base were flowering, at measured intervals, a variety of those plants
to which Linnæus has given the name of _Equinoctial flowers_, since
they open and close at certain and exact hours of the day, and thus by
proper arrangement constitute the HOROLOGE OF FLORA,(1)[2] or Nature’s
time-piece. It had been constructed, under the direction of her mother,
by Louisa Seymour. The hour of the day at which each plant opened, was
represented by an appropriate figure of nicely trimmed box; and these,
being arranged in a circle, not only fulfilled the duty, but exhibited
the appearance of a dial.
-----
Footnote 2:
These figures refer to the additional notes at the end of the work.
-----
From this retreat several winding paths threaded their mazy way through
the deep recesses of the wood; and the wanderer, quitting for a while
the blaze of day, was refreshed by the subdued light which everywhere
pervaded the avenue, except where the hand of taste had, here and
there, turned aside the boughs, and opened a vista to bring the village
spire into view, or to gladden the sight by a rich prospect of the
distant landscape. After having descended for some way, the path,
losing its inclined direction, proceeded on a level, and thus announced
to the stranger his arrival at the bottom of the valley. What a rich
display of woodland scenery was suddenly presented to his view! A rocky
glen, in which large masses of sandstone were grouped with picturesque
boldness, terminated the path, and formed an area wherein he might gaze
on the mighty sylvan amphitheatre, which gradually rose to a towering
height above him, and seemed to interpose an insuperable barrier
between the solitude of this sequestered spot and the busy haunts of
men; not a sound assailed the ear, save the murmur of the summer
breeze, as it swept the trembling foliage, or the brawling of a small
mountain stream, which gushed from the rock, and, like an angry chit,
fretted and fumed as it encountered the obstacles that had been raised
by its own impetuosity. This was the favourite retreat of Mr. Seymour,
and he had dedicated it to the genius of geology; here had he erected a
temple to the memory of Werner, and every pillar and ornament bore
testimony to the refined taste of its architect. It consisted of a
dome, constructed of innumerable shells and corallines, and surmounted
by a marble figure of Atlas, bearing the globe on his shoulders, upon
which the name of WERNER was inscribed. The dome was supported by
twelve pillars of so singular and beautiful a construction as to merit
a particular description: the Corinthian capital of each was of
Pentelican marble; the column consisted of a spiral of about six inches
in breadth, which wound round a central shaft of not more than two
inches in diameter; upon this spiral were placed specimens of various
rocks, of such masses as to fill up the outline, and to present to the
eye the appearance of a substantial and well-proportioned pillar. These
specimens were arranged in an order corresponding with their
acknowledged geological relations; thus, the _Diluvial_ productions
occupied the higher compartments; the _Primitive_ strata, the lower
ones; and the _Secondary_ and _Transition_ series found an intermediate
place. The tessellated floor presented the different varieties of
marble, so artfully interspersed as to afford a most harmonious
combination; the _Unicoloured, variegated, Madreporic_, the
_Lumachella, Cipolino_, and _Breccia_ marbles, were each represented by
a characteristic and well-defined specimen. The alcoved ceiling was
studded with _Rock Crystal_, calcareous _Stalactites_, and beautiful
_Calcedonies_. A group of figures in _basso relievo_ adorned the wall
which enclosed about a third part of the interior of the temple, and
its subject gave evidence of the Wernerian devotion of Mr. Seymour; for
it represented a contest between Pluto and Neptune, in which the watery
god was seen in the act of wresting the burning torch from the hand of
his adversary, in order to quench it in the ocean. Mr. Seymour had
studied in the school of Freyburg, under the auspices of its celebrated
professor; and, like all the pupils of Werner, he pertinaciously
maintained the aqueous origin of our strata. But let us return to the
happy party at the Lodge, whom the reader will remember we left at
their repast. This having been concluded, and all those various
subjects discussed, and questions answered, which the school-boy, who
has ever felt the satisfaction of returning home for the holidays, will
more easily conceive than we can describe, Tom enquired of his father,
whether his old friend, Mr. Twaddleton, the Vicar of Overton, was well,
and at the Parsonage. “He is quite well,” replied Mr. Seymour, “and so
anxious to see you, that he has paid several visits, during the
morning, to enquire whether you had arrived. Depend upon it, that many
hours will not elapse before you see him.”
In that wish did Tom and the whole juvenile party heartily concur; for
the vicar, notwithstanding his oddities, was the most affectionate
creature in existence, and never was he more truly happy than when
contributing to the innocent amusement of his little “_playmates_,” as
he used to call Tom and his sisters.
It may be here necessary to present the reader with a short sketch of
the character of a person, who will be hereafter found to perform a
prominent part in the little drama of Overton Lodge.
The Rev. Peter Twaddleton, Master of Arts, and Fellow of the Society of
Antiquaries, for we must introduce him in due form, was about fifty-two
years of age, twenty of which he had spent at Cambridge, as a resident
Fellow of Jesus College. He had not possessed the vicarage of Overton
above eight or nine years; and, although its value never exceeded a
hundred and eighty pounds a year, so limited were his wants, and so
frugal his habits, that he generally contrived to save a considerable
sum out of his income, in order that he might devote it to purposes of
charity and benevolence: his charity, however, was not merely of the
hand, but of the heart; distress was unknown in his village; he fed the
hungry, nursed the sick, and cheered the unfortunate; his long
collegiate residence had imparted to his mind several peculiar traits,
and a certain stiffness of address and quaintness of manner which at
once distinguish the recluse from the man of the world; in short, as
Shakspeare expresses it, “_he was not hackneyed in the ways of men_.”
His face was certainly the very reverse to everything that could be
considered “good-looking,” and yet, when he smiled, there was an
animation that redeemed the irregularity of his angular features; so
benevolent was the expression of his countenance, that it was
impossible not to feel that sentiment of respect and admiration which
the presence of a superior person is wont to inspire; but his
superiority was rather that of the heart than of the head; not that we
would insinuate any deficiency in intellect, but that his moral
excellencies were so transcendent as to throw into the shade all those
mental qualities which he possessed in common with the world. He
entertained a singular aversion to the mathematics, a prejudice which
we are inclined to refer to his disappointment in the senate-house;
for, although he was known at Cambridge as one of those “pale beings in
spectacles and cotton stockings,” commonly called “_reading men_,” yet,
after all his exertions, he only succeeded in obtaining the “_wooden
spoon_,” an honour which devolves upon the last of the “_junior
optimes_.” Whether his failure arose from an exuberant or a deficient
genius, or, to speak _phrenologically_, from an excess in his _number
of bumps_, or a defect in his _bump of numbers_, we are really unable
to state, never having had an opportunity of verifying our suspicions
by a manual examination of his cranium; he was, however, well read in
the classics, and so devoted to the works of Virgil that he never lost
an opportunity of quoting his favourite poet; and it must be admitted,
that, although these quotations so generally pervaded his conversation
as to become irksome, they were sometimes apposite, and now and then
even witty. But notwithstanding the delight which he experienced in a
_lusus verborum_ in a learned language, of such contradictory materials
was he compossed, that his antipathy to an English pun was extravagant
and ridiculous. This peculiarity has been attributed, but we speak
merely from common report, to a disgust which he contracted for that
species of spurious wit, during his frequent intercourse with the
Johnians, a race of students who have, from time immemorial, been
identified with the most profligate class of punsters; be this,
however, as it may, we are inclined to believe that a person who
resides much amongst those who are addicted to this _vice_, unless he
quickly takes the infection, acquires a sort of constitutional
insusceptibility, like nurses, who pass their lives in infected
apartments with perfect safety and impunity. His favourite, and we
might add his only pursuit, beyond the circle of his profession, was
the study of antiquities; he was, as we have already stated, a Fellow
of the Society of Antiquaries; had collected a very tolerable series of
ancient coins, and possessed sufficient critical acumen to distinguish
between Attic _ærugo_, and the spurious _verdure_ of the modern
counterfeit. Often had he undertaken an expedition of a hundred miles
to inspect the interior of an ancient barrow, or to examine the
mouldering fragments of some newly-discovered monument; indeed, like
the connoisseur in cheese, blue-mould and decay were the favourite
objects of his taste, and the sure passports to his favour; for he
despised all _living_ testimony, but that of worms and maggots. A coin
with the head of a _living_ sovereign passed through his hands with as
little resistance as water through a sieve, but he grasped the head of
an Antonine or Otho with insatiable and relentless avarice. Mr.
Twaddleton’s figure exceeded the middle stature, and was so extremely
slender as to give him the air and appearance of a tall man. He was
usually dressed in an old-fashioned suit of black cloth, consisting of
a single-breasted coat, with a standing collar, and deep comprehensive
cuffs, and a flapped waistcoat; but so awkwardly did these vestments
conform with the contour of his person, that we might have supposed
them the production of those Laputan tailors who wrought by
mathematical principles, and held in sovereign contempt the illiterate
fashioners who deemed it necessary to measure the forms of their
customers; although it was whispered by certain censorious spinsters in
the village that the aforesaid mathematical artists were better
acquainted with the _angles_ of the Seven Dials, than with the
_squares_ of the west end. They farther surmised that the vicar’s
annual journey to London, which in truth was undertaken with no other
objects than those of attending the anniversary of the Society of
Antiquaries, on Saint George’s day, and of inspecting the cabinets of
his old crony, the celebrated medallist of Tavistock-street, was for
the laudable purpose of recruiting his wardrobe. If the aforesaid coat,
with its straggling and disproportioned suburbs, possessed an amplitude
of dimensions which ill accorded with the slender wants of his person,
this misapplied liberality was more than compensated by the rigid
economy exhibited in the _nether_ part of his costume, which evidently
had not been designed by a contemporary artisan; not so his shoes,
which, for the accommodation of those unwelcome parasites, vulgarly
called _corns_, were constructed in the form of a battledore, and
displayed such an unbecoming quantity of leather, that, as Ned Hopkins,
a subaltern wit of the village alehouse, observed, “however economical
their parson might appear, he was undoubtedly _supported in
extravagance_.” Nor did the natural association between tithes and
“_corn-bags_” escape his observation, but was repeated with various
other allusions of equal piquancy, to the no small annoyance of the
reverend gentleman, and, as he declared, to the disparagement of his
cloth.
After the social repast had been concluded, Tom proposed a ramble
through the shrubbery. He was anxious to revisit the scene of his
former sports; and Louisa readily met his wishes, for she was also
desirous of showing him the _botanical clock_, which had been planned
and completed since his absence. Mr. Seymour accompanied his children,
and, as they walked across the lawn, Tom asked his father whether he
remembered the promise he had made him on quitting home for school,
that of furnishing him with some new amusements during the holidays.
“I perfectly remember,” said his father, “the promise to which you
allude, and I hope that you equally well recollect the conditions with
which it was coupled. When your mamma gave you a copy of Mrs. Marcet’s
instructive Dialogues on Natural Philosophy, I told you that, after you
had studied the principles which that work so admirably explains, you
would have but little difficulty in understanding the philosophy of
toys, or the manner in which each produced its amusing effects; and
that, when the midsummer holidays commenced, I would successively
supply you with a new amusement, whenever you could satisfactorily
explain the principles of those you already possessed. Was not that our
contract?”
“It was,” exclaimed Tom, with great eagerness, “and I am sure I shall
win the prize, whenever you will try me, and I hope my mamma and
sisters will be present.”
“Certainly,” replied Mr. Seymour, “and I trust that Louisa and Fanny,
who are of an age to understand the subject, will not prove
uninterested spectators. John, too, will profit by our scheme; for, as
I shall necessarily require, for illustration, certain toys which can
scarcely afford any amusement to a boy of your age and acquirements, it
is but fair that they should be transferred into his hands; our little
philosopher, Matthew, will also, I am sure, enter into the spirit of
our pastimes with the greatest satisfaction.”
“Thank you! thank you! dear papa,” was simultaneously shouted by
several voices, and the happy children looked forward to the morrow
with that mixed sensation of impatience and delight which always
attends juvenile anticipations.
On the following morning, the vicar was seen approaching, and Tom and
his sisters immediately ran forward to greet him.
“My dear boy,” exclaimed the vicar, “I am truly rejoiced to see
you;--when did you arrive from school?--How goes on Virgil?--Hey, my
boy?--You must be delighted with the great Mantuan bard;--now confess,
you little Trojan, can you eat a cheesecake without being reminded of
the Harpy’s prophecy, and its fulfilment, as discovered by young
Ascanius:--
Heus! etiam _mensas_ consumimus, inquit Iulus.
ÆN. vii. 116.
“But, bless me, how amazingly you have grown! and how healthy you
look!” Tom took advantage of this pause in the vicar’s address, which
had hitherto flowed in so uninterrupted and rapid a stream as to
preclude the possibility of any reply to his questions, to inform him
that his father was on the lawn, and desirous of seeing him.
“Mr. Twaddleton,” exclaimed Mr. Seymour, “you are just in time to
witness the commencement of a series of amusements, which I have
proposed for Tom’s instruction during the holidays.”
“Amusement and instruction,” replied the vicar, “are not synonymous in
my vocabulary; unless, indeed, they be applied to the glorious works of
Virgil; but let me hear your scheme.”
“I have long thought,” said Mr. Seymour, “that all the first principles
of natural philosophy might be easily taught, and beautifully
illustrated, by the common toys which have been invented for the
amusement of youth.”
“A fig for your philosophy,” was the unceremonious and chilling reply
of the vicar. “What have boys,” continued he, “to do with philosophy?
Let them learn their grammar, scan their hexameters, and construe
Virgil; it is time enough to inflict upon them the torments of science
after their names have been entered on the University boards.”
“I differ from you entirely, my worthy friend; the principles of
natural philosophy cannot be too early inculcated, nor can they be too
widely diffused. It is surely a great object to engage the
prepossessions on the side of truth, and to direct the natural
curiosity of youth to useful objects.”
“Hoity toity!” exclaimed the reverend gentleman, “such principles
accord not with my creed; heresy, downright heresy; that a man of your
excellent sense and intelligence can be so far deceived! But the world
has run mad; and much do I grieve to find, that the seclusion of
Overton Lodge has not secured its inmates from the infection. I came
here, Mr. Seymour, to receive your sympathy, and to profit by your
counsel, but, alas! alas! I have fallen into the camp of the enemy.
‘_Medios delapsus in hostes_,’ as Virgil has it.”
“You astonish me--what can have happened?” asked Mr. Seymour.
“There is Tom Plank, the carpenter,” said the vicar, “soliciting
subscriptions for the establishment of a philosophical society. I
understand that this mania--for by what other, or more charitable term
can I express such conduct?--has seized this deluded man since his
return from London, where he has been informed that all the ‘hewers of
wood and drawers of water’ are about to associate themselves into
societies for the promotion of science. Preposterous idea! as if a
block of wood could not be split without a knowledge of the doctrine of
percussion, nor a pail of water drawn from the well without an
acquaintance with hydrostatics; but, as I am a Christian priest, I
solemnly declare, that I grieve only for my flock, and raise my feeble
voice for no other purpose than that of scaring the wolf from the fold:
to be angry, as Pope says, would be to revenge the faults of others
upon ourselves; but I am not angry, Mr. Seymour, I am vexed, sorely
vexed.”
“Take it not thus to heart, my dear vicar,” replied his consoling
friend; “‘_Solve metus_,’ as your poet has it. Science, I admit, is
both the Pallas and Pandora of mankind; its abuse may certainly prove
mischievous, but its sober and well-timed application cannot fail to
increase the happiness of every class of mankind, as well as to advance
and improve every branch of the mechanical arts; so thoroughly am I
satisfied upon this point, that I shall subscribe to the proposed
society with infinite satisfaction.”
“Mr. Seymour! Mr. Seymour! you know not what you do. Would you scatter
the seeds of insubordination? manure the weeds of infidelity? fabricate
a battering-ram to demolish our holy church? Such, indeed, must be the
effect of your Utopian scheme, for truly may I exclaim with the
immortal Maro--
In nostros fabricata est machina muros.”[3]
“Come, come, my good friend, all this is declamation without argument.”
“Without argument! Many are the sad instances which I could adduce in
proof of the evil effects which have already accrued from this
abominable system. I am not in the habit, Sir, of dealing in empty
assertion; already has the aforesaid Tom Plank ventured to question the
classical knowledge of his spiritual pastor, and, as I understand, has
openly avowed himself, at the sixpenny club, as my rival in antiquarian
pursuits.”
“And why should he not?” said the mischievous Mr. Seymour; “I warrant
you he already possesses many an _old saw_; ay, and of a very great
age, too, if we may judge from the _loss of its teeth_.”
During this remonstrance, Mr. Twaddleton had been occupied in whirling
round his steel watch-chain with inconceivable rapidity, and, after a
short pause, he burst out into the following exclamation:--
“Worthy Sir! if you persist in asserting, that a man whose occupation
is to _plane deal_, is prepared to dive into the sacred mysteries of
antiquity, I shall next expect to hear that”--
“A truce, a truce,” cried Mr. Seymour, interrupting the vicar, “to all
such hackneyed objections; and let us _deal plainly_ with your _planer
of deals_: you assert that the carpenter cannot speak grammatically,
and yet he gains his livelihood by _mending stiles_; you complain of
his presumption in argument, would it not be a desertion of his _post_
to decline _railing_? and then, again, with respect to his antiquarian
pretensions, compare them with your own; _you_ rescue _saws from the
dust_, _he_ obtains _dust_ from his saws.”
“What madness has seized my unfortunate friend?
Infelix! quæ tanta animum dementia cepit?
as Virgil has it:--But let it pass, let it pass, Mr. Seymour; my
profession has taught me to bear with humility and patience the
contempt and revilings of my brethren; I forgive Tom Plank for his
presumption, as in that case I alone am the sufferer; but I say to you,
that envy, trouble, discontent, strife, and poverty, will be the fruits
of the seeds you would scatter. I verily believe, that unless this
‘march of intellect,’ as it has been termed, is speedily checked,
Overton, in less than twelve months, will become a deserted village;
for there is scarcely a tradesman who is not already distracted by some
visionary scheme of scientific improvement, that leads to the neglect
of their occupations, and the dissipation of the honest earnings which
their more prudent fathers had accumulated; ‘_Meliora pii docuere
parentes_,’ as the poet has it. What think you of Sam Corkington, who
proposes to erect an apparatus in the crater of Mount Vesuvius, in
order to supply every city on the continent with heat and light; or of
Billy Spooner, who is about to establish a dairy at Spitzbergen, that
he may furnish all Europe with ice-cream from the milk of whales! ‘_O,
viveret Democritus!_’”
The vicar was about to proceed with his lamentations, but the thread of
his discourse was suddenly snapped asunder, and his ideas thrown into
the wildest confusion, by the explosion of a most audacious pun, which
in mercy to Mr. Seymour, as well as to our readers, we will not repeat.
“Mr. Seymour,” exclaimed the incensed vicar, “we will, if you please,
terminate our discourse; I perceive that you are determined to meet my
remonstrances with ridicule; when I had hoped to bring an argument
incapable of refutation, _Tum variæ illudunt pestes_, as Virgil has it.”
“Pray, allow me to ask,” said Mr. Seymour, “whether my puns, or your
quotations, best merit the title of _pestes_?”
“That you should compare the vile practice of punning with the elegant
and refined habit of conveying our ideas by classic symbols, does
indeed surprise and disturb me. Pope has said that words are the
counters by which men represent their thoughts; the plebeian,”
continued the vicar, “selects base metal for their construction, while
the scholar forms them of gold and gems, dug from the richest mines of
antiquity. But to what vile purpose does the punster prostitute such
counters? Not for the interchange of ideas, but, like the juggler, to
deceive and astonish by acts of legerdemain.”
“How fortunate is it that you had not lived in the reign of King
James,” remarked Mr. Seymour; “for that singular monarch, as you may,
perhaps, remember, made very few bishops who had not thus signalised
themselves.”
“To poison our ears by quibbles and quirks did well become him who
sought to deceive our senses and blind our reason--the patron of puns
and the believer in witchcraft were suitably united,” replied the vicar.
“Well,” said Mr. Seymour, “as this is a subject upon which it is not
likely that we should agree, I will pass to another, where I hope to be
more successful; I trust I shall induce you to view with more
complacency my project of teaching philosophy by the aid of toys and
sports.”
“Mr. Seymour, the proposal of instructing children in the principles of
natural philosophy, is really too visionary to require calm discussion;
and can be equalled only in absurdity by the method you propose for
carrying it into effect.”
“Come, come, my dear vicar, pray chain up your prejudices, and let your
kind spirit loose for half an hour: let me beg that you will so far
indulge me,” said Mr. Seymour, “as to listen patiently to the plan by
which it is my intention to turn sport into science, or, in other
words, toys into instruments of philosophical instruction.”
“And is it then possible,” said the vicar, in a tone of supplication,
“that you can seriously entertain so wild, and, I might even add, so
cruel a scheme? Would you pursue the luckless little urchin from the
schoolroom into the very playground, with your unrelenting tyranny? a
sanctuary which the most rigid pedagogue has hitherto held inviolable.
Is the buoyant spirit so forcibly, though perhaps necessarily,
repressed, during the hours of discipline, to have no interval for its
free and uncontrolled expansion? Your science, methinks, Mr. Seymour,
might have taught you a wiser lesson; for you must well know that the
most elastic body will lose that property by being constantly kept in a
state of tension.”
“A fine specimen of sophistry, upon my word,” cried Mr. Seymour, “which
would, doubtless, raise every nursery-governess and doating grandmother
in open rebellion against me: but let me add, that it ill becomes a man
of liberal and enlarged ideas, to suffer his opinions to be the sport
of mere words; for, that our present difference is an affair of words,
and of words only, I will undertake to prove, to the satisfaction of
any unprejudiced person. _Play_ and _work_--_amusement_ and
_instruction_--_toys_ and _tasks_--are invariably but most
unjustifiably employed as words of contrast and opposition; an error
which has arisen from the indistinct and very indefinite ideas which we
attach to such words. If the degree of mental exertion be said to
constitute the difference between _play_ and _work_, I am quite sure
that the definition would be violated in the first illustration; for
let me ask, when do boys exert so much thought as in carrying into
effect their holiday schemes? The distinction may, perhaps, be made to
turn upon the irksome feelings which might be supposed to attend the
drudgery of study, but this can never happen except from a vicious
system of education that excludes the operations of thought; a school
that locks in the body, but locks out the mind: depend upon it, Mr.
Twaddleton, that the human mind, whether in youth or manhood, is ever
gratified by the acquisition of information; every occupation soon
cloys, unless it be seasoned by this stimulant. Is not the child idle
and miserable in a nursery full of playthings, and to what expedient
does he instinctively fly to relieve his _ennui_? Why, he breaks his
toys to pieces, as Miss Edgeworth justly observes, not from the love of
mischief, but from the hatred of idleness, or rather from an innate
thirst after knowledge; and he becomes, as it were, an enterprising
adventurer, and opens for himself a new source of pleasure and
amusement, in exploring the mechanism of their several parts. Think
you, then, Mr. Twaddleton, that any assistance which might be offered
the boy, under such circumstances, would be received by him as a task?
Certainly not. The acquisition of knowledge then, instead of detracting
from, must heighten the amusement of toys; and if I have succeeded in
convincing you of this truth, my object is accomplished.”
Thus did Mr. Seymour, like an able general, assail his adversary on his
own ground; he drove him, as it were, into a corner, and by seizing the
only pass through which he could make his escape, forced him to
surrender at discretion.
“Why, truly,” replied the vicar, after a short pause, “I am ready to
admit that there is much good sense in your observations; and, if the
scientific instruction upon these occasions be not carried so far as to
puzzle the boy, I am inclined to coincide with you.”
“Therein lies the whole secret,” said Mr. Seymour: “when an occupation
agreeably interests the understanding, imagination, or passions of
children, it is what is commonly understood by the term _play_ or
_sport_; whereas that which is not accompanied with such associations,
and yet may be necessary for their future welfare, is, properly enough,
designated as a _task_.”
“I like the distinction,” observed the vicar.
“Then may I hope that you will indulge me so far as to listen to the
scheme by which it is my intention to turn ‘Sport into Science,’ or, in
other words, _Toys_ into instruments of _Philosophical Instruction_?”
The vicar nodded assent.
Mr. Seymour proceeded--“In the first place, I would give the boy some
general notions with regard to the properties of matter, such as its
gravitation, vis inertiæ, elasticity, &c. What apparatus can be
required for such a purpose, beyond some of the more simple toys?
Indeed, I will undertake to demonstrate the three grand laws of motion
by a game at ball; while the composition and resolution of forces may
be beautifully exemplified during a game of marbles, especially that of
‘ring-taw;’ but in order that you may more clearly comprehend the
capability of my plan, allow me to enumerate the various philosophical
principles which are involved in the operation of the several more
popular toys and sports. We will commence with the ball; which will
illustrate the nature and phenomena of _elasticity_, as it leaps from
the ground;--of _rotatory motion_, while it runs along its surface;--of
_reflected motion_, and of the _angles of incidence and reflection_, as
it rebounds from the wall;--and of _projectiles_, as it is whirled
through the air; at the same time the cricket-bat may serve to explain
the _centre of percussion_. A game at marbles may be made subservient
to the same purposes, and will farther assist us in conveying clear
ideas upon the subject of the _collision of elastic and non-elastic
bodies_, and of their _velocities and direction after impact_. The
_composition and resolution of forces_ may be explained at the same
time. The nature of _elastic springs_ will require no other apparatus
for its elucidation than Jack in the box, and the numerous
leaping-frogs and cats with which the nursery abounds. The leathern
sucker will exemplify the nature of _cohesion_, and the effect of water
in filling up those inequalities by which contiguous surfaces are
deprived of their attractive power; it will, at the same time,
demonstrate the nature of a _vacuum_, and the influence of _atmospheric
pressure_. The squirt will afford a farther illustration of the same
views, and will furnish a practical proof of the weight of the
atmosphere in raising a column of water. The theory of the pump will
necessarily follow. The great elasticity of air, and the opposite
property of water, I shall be able to show by the amusing exhibition of
the ‘_Bottle Imps_.’”
“Bottle Imps!--‘_Acheronta movebis_,’” muttered the vicar.
Mr. Seymour continued--“The various balancing toys will elucidate the
nature of the _centre of gravity, point of suspension_, and _line of
direction_: the seesaw, rocking-horse, and the operation of walking on
stilts, will here come in aid of our explanations. The combined effects
of momentum and a change in the centre of gravity of a body may be
beautifully exemplified by the action of the Chinese Tumblers. The
sling will demonstrate the existence and effect of _centrifugal force_;
the top and tetotum will prove the power of vertiginous motion to
support the axis of a body in an upright position. The trundling of the
hoop will accomplish the same and other objects. The game of
_bilboquet_, or cup and ball, will show the influence of rotatory
motion in steadying the rectilinear path of a spherical body, whence
the theory of the rifle-gun may be deduced. For conveying some
elementary ideas of the doctrine of _oscillation_, there is the swing.
The flight of the arrow will not only elucidate the principles of
_projectiles_, but will explain the force of the air in producing
rotatory motion by its impact on oblique surfaces: the revolution of
the shuttlecock may be shown to depend upon the same resolution of
forces. Then comes the kite, one of the most instructive and amusing of
all the pastimes of youth,--the favourite toy of Newton in his boyish
days:[4]--its ascent at once developes the theory of the composition
and resolution of forces, and explains various subordinate principles,
which I shall endeavour to describe when we arrive at the subject. The
_see-saw_ will unfold the general principle upon which the Mechanical
Powers are founded; and the boy may thus be easily led to the theory of
the _lever_, by being shown how readily he can balance the heavier
weight of a man by riding on the longer arm of the plank. The theory of
colours may be pointed out to him as he blows his soap-bubbles;[5] an
amusement which will, at the same time, convince him that the air must
exert a pressure equally in all directions. For explaining the theory
of sound, there are the whistle, the humming-top, the whiz-gig, the
pop-gun, the bull-roarer, and sundry other amusements well known in the
play-ground; but it is not my intention, at present, to enumerate _all_
the toys which may be rendered capable of affording philosophical
instruction; I merely wish to convince you that my plan is not quite so
chimerical as you were at first inclined to believe.”
“Upon my word,” said the vicar, “no squirrel ever hopped from branch to
branch with more agility,--you are the very counterpart of Cornelius
Scriblerus; but I must confess that your scheme is plausible, very
plausible, and I shall no longer refuse to attend you in the progress
of its execution.
Cedo equidem, nec, nate, tibi comes ire recuso,[6]
as Virgil has it.”
Mr. Seymour, however, saw very plainly that, although the vicar thus
withdrew his opposition, he was nevertheless very far from embarking in
the cause with enthusiasm, and that, upon the principle already
discussed, he would perform his part rather as a _task_ than a
_pastime_. Nor was the line which Mr. Twaddleton had quoted from the
Æneid calculated to efface such an impression. It was true, that, like
Anchises, he no longer refused to accompany him in his expedition; but,
if the comparison were to run parallel, it was evident that he would
have to carry him as a dead weight on his shoulders. This difficulty,
however, was speedily surmounted by an expedient, with which the reader
will become acquainted by the recital of what followed.
“I rejoice greatly,” said Mr. Seymour, “that we have at length
succeeded in enlisting you into our service; without your able
assistance, I fear that my instruction would be extremely imperfect;
for you must know, my dear sir, that I am ambitious of making Tom an
antiquary as well as a philosopher, and I look to you for a history of
the several toys which I shall have occasion to introduce.”
This propitiatory sentence had its desired effect.
“Most cheerfully shall I comply with your wishes,” exclaimed the
delighted vicar; “and I can assure you, sir, that, with regard to
several of the more popular toys and pastimes, there is much very
curious and interesting lore.”
Mr. Seymour had upon this occasion succeeded in opening the heart of
the vicar, just as a skilful mechanic would pick a patent lock; who,
instead of forcing it by direct violence, seeks to discover the secret
spring to which all its various movements are subservient.
“To-morrow, then,” cried the vicar, in a voice of great exultation, “we
will commence our career, from which I anticipate the highest
satisfaction and advantage; in the mean time,” continued he, “I will
refresh my memory upon certain points touching the antiquities of these
said pastimes, or, as we used to say at college, _get up_ the subject.
I will also press into our service my friend and neighbour Jeremy
Prybabel, whose etymological knowledge will greatly assist us in
tracing the origin of many of the words used in our sports, which is
frequently not very obvious.”
Mr. Seymour cast an intelligible glance at his wife, who was no less
surprised at the sudden change in the vicar’s sentiments than she was
pleased with the skill and address by which it had been accomplished.
[Illustration: Kite with a smiling face, on a table with various other
toys.]
-----
Footnote 3:
“An engine’s raised to batter down our walls.”—ÆN. ii. 46.
Footnote 4:
Sir Isaac Newton is said to have been much attached to
Philosophical sports when a boy; he was the first to introduce
paper kites at Grantham, where he was at school. He took pains to
find out their proper proportions and figure, and the proper place
for fixing the string to them. He made lanterns of paper crimpled,
which he used to go to school by in winter mornings with a candle,
and he tied them to the tail of his kites in a dark night, which at
first frightened the country people exceedingly, who took his
candles for comets.--_Thomson’s Hist. of R.S._
Footnote 5:
The colours which glitter on a soap-bubble are the immediate
consequence of a principle the most important from the variety of
phenomena it explains, and the most beautiful from its simplicity and
compendious neatness in the whole science of Optics.--_Herschel’s
Preliminary Discourses._
Footnote 6:
“I yield, my son, and no longer refuse to become your
companion.”--ÆN. ii. 704.
------------------------------------------------------------------------
[Illustration: Seven people gathered around a well.]
CHAPTER II.
_On Gravitation.--Weight.--The Velocity of Falling Bodies.--At what
Altitude a Body would lose its Gravity.--The Tower of
Babel.--The known Velocity of Sound affords the means of
calculating Distances.--An Excursion to Overton Well.--An
Experiment to ascertain its Depth.--A Visit to the
Vicarage.--The Magic Gallery.--Return to the Lodge._
It was about two o’clock, when Mr. Twaddleton, in company with Mr. and
Mrs. Seymour, joined the children on the lawn.
“Tom,” said his father, “are you prepared to commence the proposed
examination?”
“Quite ready, papa.”
“Then you must first inform me,” said Mr. Seymour, taking the ball out
of Rosa’s hand, “why this ball falls to the ground, as soon as I
withdraw from it the support of my hand?”
“Because every _heavy_ body that is not supported, must of course fall.”
“And every _light_ one also, my dear; but that is no answer to my
question; you merely assert the fact, without explaining the reason.”
“Oh! now I understand you; it is owing to the force of gravity; the
earth attracts the ball, and the consequence is, that they both come in
contact;--is not that right?”
“Certainly; but if the earth attract the ball, it is equally true that
the ball must attract the earth; for you have, doubtless, learnt that
bodies mutually attract each other; tell me, therefore, why the earth
should not rise to meet the ball?”
“Because the earth is so much larger and heavier than the ball.”
“It is, doubtless, much larger, and since the force of attraction is in
proportion to the mass, or quantity of matter, you cannot be surprised
at not perceiving the earth rise to meet the ball, the attraction of
the latter being so infinitely small, in comparison with that of the
former, as to render its effect wholly nugatory; but with regard to the
earth being heavier than the ball, what will you say when I tell you
that it has no weight at all?”
“No weight at all!”
Tom begged that his father would explain to him how it could possibly
be that the earth should not possess any weight.
“Weight, my dear boy, you will readily understand, can be nothing more
than an effect arising out of the resisted attraction of a body for the
earth: you have just stated, that all bodies have a tendency to fall,
in consequence of the attraction of gravitation; but if they be
supported, and prevented from approaching the earth, either by the
hand, or any other appropriate means, their tendency will be felt, and
is called _weight_.”
Tom understood this explanation, and observed, that “since attraction
was always in proportion to the quantity of matter, so, of course, a
larger body must be more powerfully attracted, or be _heavier_, than a
smaller one.”
“Magnitude, or size, my dear, has nothing whatever to do with quantity
of matter: will not a small piece of lead weigh more than a large piece
of sponge? In the one case, the particles of matter may be supposed to
be packed in a smaller compass; in the other, there must exist a
greater number of pores or interstices.”
“I understand all you have said,” observed Louisa, “and yet I am unable
to comprehend why the earth cannot be said to have any weight.”
“Cannot you discover,” answered Mr. Seymour, “that, since the earth has
nothing to attract it, it cannot have any attraction to resist, and,
consequently, according to the ordinary acceptation of the term, it
cannot be correctly said to possess weight? although I confess that,
when viewed in relation to the solar system, a question will arise upon
this subject, since it is attracted by the sun.”
The children declared themselves satisfied with this explanation, and
Mr. Seymour proceeded to put another question: “Since,” continued he,
“you now understand the nature of that force by which bodies fall to
the earth, can you tell me the degree of velocity with which they fall?”
Tom asserted that the weight of the body, or its quantity of matter,
and its distance from the surface of the earth, must, in every case,
determine that circumstance; but Mr. Seymour excited his surprise by
saying, that it would not be influenced by either of those conditions;
he informed them, for instance, that a cannon-ball, and a marble, would
fall through the same number of feet in a given time, and that, whether
the experiment were tried from the top of a house, or from the summit
of Saint Paul’s, the same result would be obtained.
“I am quite sure,” exclaimed Tom, “that, in the _Conversations on
Natural Philosophy_, it is positively stated, that _attraction is
always in proportion to the quantity of matter_.”
“Yes,” observed Louisa, “and it is moreover asserted, that the
_attraction diminishes as the distances increase_.”
Mr. Seymour said, that he perceived the error under which his children
laboured, and that he would endeavour to remove it. “You cannot, my
dears,” continued he, “divest your minds of that erroneous but natural
feeling, that a body necessarily falls to the ground without the
exertion of any force: whereas, the greater the quantity of matter, the
greater must be the force exerted to bring it to the earth: for
instance, a substance which weighs a hundred pounds will thus require
just ten times more force than one which only weighs ten pounds; and
hence it must follow, that both will come to the ground at the same
moment; for, although, in the one case, there is ten times more matter,
there is, at the same time, ten times more attraction to overcome its
resistance; for you have already admitted that the force of attraction
is always in proportion to the quantity of matter. Now let us only for
an instant, for the sake merely of argument, suppose that attraction
had been a force acting without any regard to quantity of matter, is it
not evident that, in such a case, the body containing the largest
quantity would be the slowest in falling to the earth?”
“I understand you, papa,” cried Tom: “if an empty waggon travelled four
miles an hour, and were afterwards so loaded as to have its weight
doubled, it could only travel at the rate of two miles in the same
period, provided that in both cases the horses exerted the same
strength.”
“Exactly,” said Mr. Seymour; “and to follow up your illustration, it is
only necessary to state, that Nature, like a considerate master, always
apportions the number of horses to the burthen that is to be moved, so
that her loads, whatever may be their weight, always travel at the same
rate; or, to express the fact in philosophical instead of figurative
language, gravitation, or the force of the earth’s attraction, always
increases as the quantity of matter, and, consequently, that heavy and
light bodies, when dropped together from the same altitude, must come
to the ground at the same instant of time.”
Louisa had listened with great attention to this explanation; and
although she thoroughly understood the argument, yet it appeared to her
at variance with so many facts with which she was acquainted, that she
could not give implicit credence to it.
“I think,” papa, said the archly-smiling girl, “I could overturn this
fine argument by a very simple experiment.”
“Indeed! Miss Sceptic: then pray proceed; and I think we shall find,
that the more strenuously you oppose it, the more powerful it will
become: but let us hear your objections.”
“I shall only,” replied she, “drop a shilling, and a piece of paper,
from my bed-room window upon the lawn, and request that you will
observe which of them reaches the ground first; if I am not much
mistaken, you will find that the coin will strike the earth before the
paper has performed half its journey.”
Tom appeared perplexed, and cast an enquiring look at his father.
“Come,” said Mr. Seymour, “I will perform this experiment myself, and
endeavour to satisfy the doubts of our young sceptic; but I must first
take the opportunity to observe, that I am never better pleased than
when you attempt to raise difficulties in my way, and I hope you will
always express them without reserve.”
“Here, then, is a penny piece; and here,” said Tom, “is a piece of
paper.”
“Which,” continued Mr. Seymour, “we will cut into a corresponding shape
and size.” This having been accomplished, he held the coin in one hand,
and the paper disc in the other, and dropped them at the same instant.
“There! there!” cried Louisa, with an air of triumph; “the coin reached
the ground long before the paper.”
“I allow,” said Mr. Seymour, “that there was a distinct interval in
favour of the penny piece;” and he proceeded to explain the cause of
it. He stated that the result was not contrary to the law of
gravitation, since it arose from the interference of a foreign body,
the air, to the resistance of which it was to be attributed; and he
desired them to consider the particles of a falling body as being under
the influence of two opposing forces,--gravity, and the air’s
resistance. Louisa argued, that the air could only act on the surface
of a body, and as this was equal in both cases (the size of the paper
being exactly the same as that of the penny piece), she could not see
why the resistance of the air should not also be equal in both cases.
“I admit,” said Mr. Seymour, “that the air can only act upon the
surface of a falling body, and this is the very reason of the paper
meeting with more resistance than the coin; for the latter, from its
greater density, must contain many more particles than the paper, and
upon which the air cannot possibly exert any action; whereas almost
every particle of the paper may be said to be exposed to its
resistance, the fall of the latter must therefore be more retarded than
that of the former body.”
At this explanation Louisa’s doubts began to clear off, and they were
ultimately dispelled on Mr. Seymour performing a modification of the
above experiment in the following manner. He placed the disc of paper
in close contact with the upper part of the coin, and, in this
position, dropped them from his hand. They both reached the ground at
the same instant.
“Are you now satisfied, my dear Louisa?” asked her father. “You
perceive that, by placing the paper in contact with the coin, I
skreened it from the action of the air, and the result is surely
conclusive.”
“Many thanks to you, dear papa; I am perfectly satisfied, and shall
feel less confident for the future.” Tom was delighted; for, as he
said, he could now understand why John’s paper _parachute_ descended so
deliberately to the ground; he could also explain why feathers, and
other light bodies, floated in the air. “Well then,” said Mr. Seymour,
“having settled this knotty point, let us proceed to the other
question, viz. ‘that a body will fall with the same velocity, during a
given number of feet, from the ball of St. Paul’s as from the top of a
house.’ You maintain, I believe, that, since the attraction of the
earth for a body diminishes as its distance from it increases,[7] a
substance at a great height ought to fall more slowly than one which is
dropped from a less altitude.”
Neither Tom nor Louisa could think otherwise. Mr. Seymour told them
that, _in theory_, they were perfectly correct, but that, since
attraction acted from the centre, and not from the surface of the
earth, the difference of its force could not be discovered at the small
elevations to which they could have access: “for what,” said he, “can a
few hundred feet be in comparison with four thousand miles, which is
the distance from the centre to the surface of our globe?--You must
therefore perceive that, in all ordinary calculations respecting the
velocity of falling bodies, we may safely exclude such a consideration.”
“But suppose,” said Tom, “it were possible to make the experiment a
thousand miles above the earth, would not the diminished effect of
gravity be discovered in that case?”
“Undoubtedly,” replied his father, “indeed it would be sensible at a
much less distance: for instance, if a lump of lead, weighing a
thousand pounds, were carried up only four miles, it would be found to
have lost two pounds of its weight.” (2)
“This discussion,” observed Mr. Twaddleton, “reminds me of a problem
that was once proposed at Cambridge, to find the elevation to which the
Tower of Babel could have been raised, before the stones would have
entirely lost their gravity.”
“Its solution,” said Mr. Seymour, “would require a consideration which
Tom could not possibly understand at present, viz. the influence of the
_centrifugal force_.”
“I am fully aware of it,” replied the vicar, “and in order to
appreciate that influence, it would, of course, be necessary to take
into account the latitude of the place; but, if my memory serves me, I
think that under the latitude of 30°, which I believe is nearly that of
the plains of Mesopotamia, the height would be somewhere about
twenty-four thousand miles.”
Mr. Seymour now desired Tom to inform him, since all bodies fall with
the _same_ velocity, what that velocity might be.
“Sixteen feet in a second, papa;--I have just remembered that I had a
dispute with a school-fellow upon that subject, and in which, thanks to
Mrs. Marcet, I came off victorious, and won twelve marbles.”
“Then let me tell you, my fine fellow, that unless your answer
exclusively related to the _first_ second of time, you did not win the
marbles fairly; for, since the force of gravity is continually acting,
so is the velocity of a falling body continually increasing, or it has
what is termed an ‘_accelerating velocity_;’ it has accordingly been
ascertained by accurate experiments, that a body descending from a
considerable height falls sixteen feet, as you say, in the _first_
second of time; but _three times sixteen_ in the next; _five times
sixteen_ in the third; and _seven times sixteen_ in the fourth; and so
on, continually increasing according to the odd numbers 1, 3, 5, 7, 9,
11, &c. so that you perceive,” continued Mr. Seymour, “by observing the
number of seconds which a stone requires to descend from any height, we
can discover the altitude, or depth, of the place in question.”
Louisa and Fanny, who had been attentively listening to their father’s
explanation, interchanged a smile of satisfaction, and, pulling Tom
towards them, whispered something which was inaudible to the rest of
the party.
“Come, now,” exclaimed Mr. Seymour, “I perceive by your looks that you
have something to ask of me: is Louisa sceptical again?”
“Oh dear no,” replied Tom; “Louisa merely observed, that we might now
be able to find out the depth of the village well, about which we have
all been very curious; for the gardener has told us that it is the
deepest in the kingdom, and was dug more than a hundred years ago.”
Mr. Seymour did not believe that it was the deepest in the kingdom,
although he knew that its depth was considerable; and he said that, if
Mr. Twaddleton had no objection, they should walk to it, and make the
proposed experiment.
“Objection! my dear Mr. Seymour, when do I ever object to afford
pleasure to my little playmates, provided its indulgence be harmless?
Let us proceed at once, and on our return I hope you will favour me
with a visit at the vicarage; I have some antiquities which I am
anxious to exhibit to yourself and Mrs. Seymour.” Tom and Rosa each
took the vicar’s hand, and Mr. and Mrs. Seymour followed with Louisa
and Fanny. The village well was about half a mile distant; the road to
it led through a delightful shady lane, at the top of which stood the
vicarage-house. Mr. and Mrs. Seymour and her daughters had lingered in
their way to collect botanical specimens; and when they had come up to
Tom and the vicar, they found them seated on the trunk of a
newly-felled oak, in deep discourse.
“What interests you, Tom?” said Mr. Seymour, who perceived, by the
enquiring and animated countenance of the boy, that his attention had
been excited by some occurrence.
“I have been watching the woodman,” said Tom, “and have been surprised
that the sound of his hatchet was not heard until some time after he
had struck the tree.”
“And has not Mr. Twaddleton explained to you the reason of it?” asked
Mr. Seymour.
“He has,” replied Tom, “and he tells me that it is owing to sound
travelling so much more slowly than light.”
“You are quite right; and as we are upon an expedition for the purpose
of measuring depths, it may not be amiss to inform you, that this fact
furnishes another method of calculating distances.”
The party seated themselves upon the oak, and Mr. Seymour
proceeded--“The stroke of the axe is seen at the moment the woodman
makes it, on account of the immense velocity with which light
travels;(3) but the noise of the blow will not reach the ear until some
time has elapsed, the period varying, of course, in proportion to the
distance, because sound moves only at the rate of 1142 feet in a
second, or about 13 miles in a minute; so that you perceive, by
observing the time that elapses between the fall of the hatchet and the
sound produced by it, we can ascertain the distance of the object.”
Mr. Seymour fixed his eye attentively on the woodman, and, after a
short pause, declared that he was about half a quarter of a mile
distant.
“Why, how could you discover that?” cried Louisa; “you had not any
watch in your hand.”
“But,” said Mr. Seymour, “you might have perceived that I placed my
finger on my wrist, and as my pulse beats about 75 strokes in a minute,
I was able to form a tolerable estimate of the interval, although I
confess that it is a very rough experiment, but sufficiently accurate
for the purpose of illustration. In the same manner we can readily
ascertain the distance of a thundercloud, or that of a vessel at sea
firing a cannon. If we do not hear the thunder till half a minute after
we see the lightning, we are to conclude the cloud to be at the
distance of six miles and a half. But let us proceed to the well.”
After a walk of a few minutes, the party reached the place of
destination. On their arrival Mr. Seymour enquired who would count the
time.
“Be that office mine,” said Mr. Twaddleton, as he extracted a large
silver time-piece from the dark abyss of his watch-pocket; “and let
Tom,” continued he, “find a pebble.”
“Here is one,” cried Louisa.
“Very well: now, then, how will you proceed?” asked Mr. Seymour.
“I shall drop the stone,” replied Tom, “into the well, and observe how
many seconds it will be before it touches the water, and I shall then
set down the number of feet it will fall in each second, and add up the
numbers.”
“That,” said Mr. Seymour, “would certainly accomplish your object; but
I can give you a neater, as well as a shorter rule for performing the
sum: you shall, however, first work it in your own way;--but you have
not yet informed me how you propose to ascertain the moment at which
the stone reaches the water.”
“By the sound, to be sure, papa; and you will find that a very loud one
will be produced.”
“If the depth of the well be considerable, such a plan will not answer
the purpose, since, in that case, there must necessarily be a
perceptible interval between the fall of the stone and the sound
produced by it, as you have just seen exemplified by the woodman,
which, unless taken into account,(4) will vitiate the result.”
Tom observed that he had not thought of that difficulty, and did not
know how he could get over it. His father told him, that he must look
at the surface of the water, and mark the moment it was disturbed by
the stone.
“Now, Mr. Twaddleton,” exclaimed Mr. Seymour, “are you ready to count
the seconds?”
“Quite ready.”
“Then drop the stone.”
“One,--two,--three,--four--”
“There,” said Tom, “it touched the water.”
“And there, there,” cried several voices, “what a noise it made!”
“_Facilis descensus Averni_,” exclaimed the vicar; “the stone descended
in four seconds.”
“Now, my boy, make your calculation.”
Mr. Seymour furnished pencil and paper, and Tom proceeded;--“_Sixteen_
feet for the first second,--I put that down.”--
“Well,” said his father, “and _three_ times _sixteen_ for the second?”
“_Forty-eight_,” cried Tom.--
“Put it down.”
“_Five times sixteen_, for the third?”
“_Eighty._”--
“Down with it.”
“And _seven times sixteen_, for the fourth?”
“_One hundred and twelve._”
“Now, cast up these numbers,” said Mr. Seymour.
“_Two hundred and fifty-six feet_,” cried Tom, “is the depth of the
well.”
A shout of delight, from the whole juvenile party, announced the
satisfaction which they felt at the success of their first experiment
in NATURAL PHILOSOPHY.
Louisa observed, that she could not distinguish any interval between
the actual contact of the stone with the water and the sound which it
produced.
“At so small a distance as two hundred and fifty-six feet,” said her
father, “the interval could not have exceeded in duration the fourth
part of a second, and was, consequently, imperceptible: we might
therefore, in the present instance, have accepted the sound as a signal
of the stone’s arrival at the water, without prejudice to the result of
the experiment.”
Mr. Seymour told his son, that the method which he had pursued was
unobjectionable when the experiment did not extend beyond a few
seconds: but that, if a case occurred in which a greater space of time
were consumed, he would find his plan tedious: “Now,” continued he, “I
will give you a general rule that will enable you to obtain the answer
in a shorter time without the details of addition. ‘_The spaces
described by a falling body increase as the squares of the times
increase._’ I conclude that you already know that the _square_ of a
number is the sum obtained by multiplying the number into itself.”
“Certainly,” answered Tom; “the square of 4 is 16; that of 3, 9, and so
on.”
“This, then, being the case, you have only to square the number of
seconds, and then multiply that product by 16, being the space
described by the falling body in the first second, and you will have
the required answer: apply this rule to the present case; the stone
fell to the bottom in four seconds; square this number, 4×4=16;
multiply this by 16, and we obtain 256.”
“That,” said Tom, “is certainly much more simple than my method.”
“And it has the advantage,” continued Mr. Seymour, “of being more
portable for the memory.”
“Should any of the villagers observe us,” said Mrs. Seymour, “they will
take us for a party of fortune-tellers.”
“Of fortune-tellers!” repeated Louisa, with surprise.
“Yes, my dear,” replied Mrs. Seymour, “there is a foolish superstition
attached to this, and I believe to many other wells in the
neighbourhood of remote villages, that by dropping pebbles into it, and
observing whether they produce a loud, or only a slight sound, and
noticing the number of times they rebound from the sides before they
reach the bottom, and other absurd distinctions, a person can predict
whether good or evil awaits them.” (5)
Mrs. Seymour now proposed the party’s return to the Lodge; but Mr.
Twaddleton expressed a hope that they would first favour him with a
visit at the vicarage; to which proposition they readily assented.
His antiquated residence, mantled in ivy, and shaded by cypress, stood
on the confines of the church-yard, from which his grounds were merely
separated by a dwarf hedge of sweet-brier and roses; so that the vicar
might be said to reside amidst the graves of his departed parishioners,
and the turf-clad heap evinced the influence of his fostering care by a
grateful return of primroses and violets.
Around the house the reverend antiquary had arranged several precious
relics, which were too cumbrous for admission within its walls; amongst
these was an ancient cross, raised upon a platform on four steps, which
from the worn appearance of the stones had evidently been impressed
with the foot of many a wandering pilgrim. These mouldering monuments
of ancient days cast a shade of solemnity around the dwelling, and
announced its inmate as a person of no ordinary stamp.
Annette, the vicar’s trusty servant, had watched the approach of the
squire and his family, and, anticipating the honour of a passing visit,
was busily engaged in removing the chequed covers from the cumbrous
oaken chairs, and the various other bibs and tuckers with which his
curiosities were invested, when the party entered the study. Lucky was
it for the vicar’s repose, that the notice had been so short, or the
tidy housewife would, without doubt, have scoured some of the antique
commodities, and destroyed a crop of sacred verdure, which ages could
not have replenished. As matters stood, nothing was left for poor
Annette, but to defend her character at the expense of her master, who
she declared treated her as though she was an old witch, whenever she
was seen with a _broom_.
“Why, papa,” exclaimed Tom, as he cast his eyes around the study, “all
these curiosities have been put up since I went to school.”
“The boy is right,” said the vicar; “I have only just completed their
arrangement, and I believe,” continued he, addressing himself to Mr.
Seymour, “that there are several rich morsels of antiquity which you
have not yet seen: but I must, in the first place, introduce my young
friends to the wonders of my magic gallery; wherein they may converse
with the spirits of departed emperors, heroes, patriots, sages, and
beauties;--contemplate, at their leisure, the countenances of the
Alexanders, Cæsars, Pompeys, and Trajans;--behold a legion of
allegorical and airy beings, who have here, for the first time, assumed
appropriate and substantial forms:--examine the models of ancient
temples and triumphal arches, which, although coeval with the edifices
they represent, are as perfect as at the first moment of their
construction, while the originals have long since crumbled into dust.
They shall also see volumes of history, condensed into a space of a few
inches, and read the substance of a hundred pages at a single glance.”
“How extraordinary!” said Tom: “why we never read anything more
wonderful in our Fairy Tales.”
“And what renders it more wonderful,” replied the vicar, “is its being
all true.”
So saying, the antiquary took a key of pigmy dimensions from the pocket
of his waistcoat, and proceeded to a cumbrous ebony cabinet which stood
in a deep recess, and displayed an antique structure, and curiously
carved allegorical devices, in strict unison with that air of mystery
with which the vicar had thought proper to invest its contents. It was
supported by gigantic eagles’ claws; its key-hole was surrounded by
hissing snakes; while the head of Cerberus, which constituted the
handle, appeared as if placed to guard the entrance. The children were
upon the tiptoe of expectation and impatience--the vicar applied the
key with the wonder-stirring exclamation of “OPEN SESAMA!”--the lock
yielded, and the doors flew open. Disappointment and chagrin were
visibly depicted on the countenances of the brother and sisters.
“And so,” exclaimed Tom, “this fine magic gallery turns out to be
nothing more than a box full of rusty halfpence!”
“I am sure,” said Louisa, “it was quite unnecessary to have engaged
Cerberus as a sentinel over such rubbish.”
“Hush!” cried the vicar; “you talk like one not initiated in the
mysteries of enchantment: have you not read, that under its spells the
meanest objects have assumed forms of splendour and magnificence?” [8]
“Like the fabled touch of the Phrygian monarch,” said Mrs. Seymour,
“which we are told transmuted the meanest materials into gold.”
“In like manner, then, may treasures of the greatest value appear to
ordinary eyes as mean and worthless.”
“This cabinet,” continued Mr. Twaddleton, “is under the influence of a
potent magician; by the touch of her wand, it would become irradiated
as with celestial light, and these rusty coins would be transformed
into all those various objects of interest and delight which I had
promised to show you.”
Tom and Louisa looked at the coins, then at the vicar, and afterwards
at Mr. Seymour, to whom they cast an enquiring glance.
“Then pray,” exclaimed Tom, “wave this mighty wand of your enchantress,
and fulfil your promise.”
“The enchantress,” replied the vicar, “is not disposed to grant her
favours to those by whom she has not been propitiated.”
“And what ceremony does she require?” enquired Louisa.
“The perusal of sundry mystic volumes; and the consumption of a
midnight lamp at her altar,” replied the vicar.
“Do you not comprehend the allegory?” said Mr. Seymour. “The enchanted
gallery is no other than a collection of antique medals;--the potent
enchantress, ERUDITION, or that classical learning, without which they
appear of less value than so many rusty halfpence.”
“You are right,” cried Mr. Twaddleton: “the poetical import of a device
can be alone felt and appreciated by those who are acquainted with the
classical subjects to which it alludes; for, as Addison forcibly
observes, there is often as much thought on the reverse of a medal as
in a canto of Spenser; besides, how frequently do you meet with hints
and suggestions in an ancient poet, that give a complete illustration
to the actions, ornaments, and antiquities which are found on
coins!--In short, the person who examines a collection of medals,
without a competent knowledge of the classics, is like him who would
explore a subterranean cavern without the aid of a torch.”
“I have already learned one fact,” said Louisa, “with which I was
certainly unacquainted; that the ancients possessed a much greater
variety of money than modern nations.” (6)
“Of that, my dear,” replied the vicar, “there is some doubt;--the
learned are divided upon the question: some authors maintain that every
medal, and even medallion, had its fixed and regular price in payments,
while others, on the contrary, assert that we are not in the possession
of any real money of the ancients, and that the medals never had any
currency as coins. The truth probably is between these two extremes.”
“If these medals were not used as money,” observed Louisa, “for what
purposes could they have been coined?”
“To perpetuate the memory of great actions; and, faithful to its charge
of fame, the medal has transmitted events, the history of which must,
otherwise, have long since perished. Nay, more,” exclaimed the vicar,
his voice rising as he became warmed by his subject, “the lamp of
history has been often extinguished, and the medalist has collected
sparks from the ashes of antiquity which have rekindled its flame. You
perceive, therefore,” continued the reverend antiquary, “that such
collections are of the highest importance, and if your papa will allow
you to pass a morning in their examination, I shall easily bring you to
admit, that I have not exaggerated the wonders of my magic gallery. I
will convince you, that it contains a series of original miniature
portraits of the greatest heroes of antiquity; a compendious chart of
history, chronology, and heathen mythology; a system of classic
architecture; and an accurate commentary upon the more celebrated poems
of Greece and Rome. Ay, and I will show you a faithful resemblance of
the very ship that carried Æneas to Italy, and of the lofty poop from
which the luckless Palinurus fell into the ocean.”
Mr. Twaddleton then favoured Mr. and Mrs. Seymour with a sight of some
of those rarer medals, which he considered as constituting the gems of
his collection.
“You do not mean to say,” exclaimed Tom, as he seized a small coin,
“that this _brass_ piece is of more value than the large coin of gold
that lies next to it?”
“Mercy upon us!” cried the vicar, in a tone of agony, “how the boy
handles it!--restore it to its place--gently--gently--that ‘little
brass piece,’ as you call it, is gold, and although it might not have
been worth one guinea fifteen hundred years ago, is now valued at a
hundred. It is a coin of Ptolemy the 8th of Egypt. On the obverse is
the portrait of the king beautifully raised; on the reverse a
cornucopia. I do not believe that the coin was known to Pinkerton when
he wrote his Essay.”
“There is, certainly,” said Mr. Seymour, “something very inexplicable
in the tastes and enthusiastic feelings of you patrons of antiquity.”
“The antiquary,” observed the vicar, “does not regard a cabinet of
medals as a treasure of money, but of knowledge; nor does he fancy any
charms in gold, but in the figures that adorn it; it is not the metal,
but the erudition, that stamps it with value.”
Mr. Twaddleton now passed on to a different compartment of his cabinet,
observing, that he must exhibit a few of his Roman treasures. “Behold,”
said he, “two gems of unappreciable value; never do I look upon them
but with feelings of the purest delight. Let my young friends come
nearer, and inspect them minutely. This is a large brass coin of
Tiberius, and was current when Christ was upon the earth; next to it
lies a silver _Denarius_ of the same Emperor; its value was about equal
to seven-pence of our money, and was the coin that tempted Judas to
betray his master.”
“I think,” said Mrs. Seymour, “I have heard you speak of some English
coins of rarity and interest.”
“True, Madam, very true, but they are in another cabinet: before I
close the present one, I will, with your permission, give you a glimpse
at my Sulphurs Paduans, and Beckers.”
“Paduans and Beckers!” exclaimed Mr. Seymour, “and pray what may they
be? I never before heard the terms.”
“‘My poverty but not my will consents,’ The antiquary who is poor in
purse,” observed the vicar, “must needs be contented with being rich in
counterfeits, or, I ought rather to have said, in possessing copies
instead of originals. Becker was an artist of Frankfort, who excelled
in imitating ancient coins, but he never used his skill for the purpose
of deception, but honestly sold his productions as avowed copies, which
are admitted into the cabinets of the curious under the name of
_Beckers_. The _Paduans_,” the vicar added, “derived their name from
two brothers at Padua, celebrated for the accuracy with which they
imitated large Roman coins. Here are the English coins you alluded to,”
said the antiquary to Mrs. Seymour. “This is a shilling of Henry VII.
curious as being the first shilling ever struck; it was presented to me
by a college friend some years ago, and I have been lately informed
that it is so rare as to fetch twenty-five pounds; but let me beg you
to examine attentively this curious little treasure,” said the vicar,
his eyes twinkling with pleasure as he placed the dainty morsel in the
hand of Mrs. Seymour; “it is,” continued he, “a silver groat of Perkin
Warbeck; on one side are the Royal arms, but without a name; they are
surmounted, you perceive, with an arched crown, and placed between a
fleur de lis and a rose.”
“What is the inscription?” asked Mrs. Seymour.
“Say _legend_, Madam, if you please; the words are, ‘_Domine, salvum
fac regem_,’ the date 1494. The coin is supposed to have been struck by
the order of the Duchess of Burgundy for Perkin Warbeck, when he set
out to invade England.”
“Pray,” said Tom, “have you got a Queen Anne’s farthing?”
“It is really curious,” observed the vicar, “that well-informed persons
should still continue to be deceived with regard to the value of this
coin. The absurd notion of its being worth 100_l._ arose from an
advertisement of an old lady, who had lost one, stating it to be one of
the only three known in the world, and worth at least 100_l._ The truth
is, I understand from my much valued friend of Tavistock-Street, that
these farthings generally fetch from five to twenty shillings each;
there are several different types of them, but the only one intended
for currency is that bearing the date of 1714; all the others were
struck as patterns. This is certainly scarce, in consequence of the
death of the Queen taking place before the coinage was finished. The
farthing and sixpence of Oliver Cromwell are much more scarce and
valuable, the one generally brings 10_l._ the other as much as 25_l._
It appears that, after Oliver had stamped his head upon them, he was
afraid to issue them as current coins, which accounts for the few which
have been handed down to us.”
“You remind me,” said Mr. Seymour, “of a story I lately heard of a
crown-piece of Oliver selling at a public auction for as much as two
hundred guineas--can it be possible?”
“You labour under a mistake,” answered the vicar; “the coin you allude
to is known amongst collectors by the name of the Petition crown of
Charles the Second, and it is undoubtedly a most inimitable piece of
workmanship. The story is this: Simon, the artist, had been employed by
Oliver Cromwell, and at the Restoration, in order to obtain the
patronage of Charles, executed the crown-piece in question. It
resembles in its general appearance the common milled five-shilling
piece, but on the edging there are two lines of letters beautifully
executed. The words are ‘_Thomas Simon most humbly prays your Majesty
to compare this his tryal piece with the Dutch, and if more truly drawn
and embossed, more gracefully ordered, and more accurately engraven, to
relieve him_.’”
“And what said Charles to it?” enquired Mrs. Seymour.
“Charles,” said the vicar, “took no notice of him, on account of his
having worked for Cromwell, and the poor artist shortly afterwards died
of a broken heart.”
“Well,” exclaimed Mr. Seymour, “his manes must be surely appeased, if
his crowns now sell for two hundred guineas each.”
The party, soon after this exhibition, quitted the vicarage, highly
gratified, and returned to the Lodge, where, after the usual ceremonies
at the toilet, they sat down to dinner; in the enjoyment of which we
will now leave them, and put an end to the present chapter.
[Illustration: Stone cross.]
-----
Footnote 7:
Gravity, or the tendency of a body to approach the earth, is
proportioned to the _square of the distance_; that is, if a body be
attracted by the earth at a certain distance, with a certain force,
and be afterwards removed to _twice_ the distance, it will now be
attracted, not _half_ us much, but only _one-fourth_ as much as it
was before; and if it be removed to _three_ times the first distance,
it will be attracted not _one-third_ as much, but _one-ninth_, as
much as before; four being the square of two, and nine the square of
three.
Footnote 8:
In the legends of Scottish superstition, the magic power of imposing
upon the eye-sight was termed _Glamour_.
“It had much of glamour might:
Could make a ladye seem a knight;
The cobwebs on a dungeon wall,
Seem tapestry in lordly hall;
A nutshell seem a gilded barge,
A sheeling seem a palace large,
And youth seem age, and age seem youth:--
All was delusion, nought was truth.”
_Lay of the Last Minstrel._--Canto 3. ix.
CHAPTER III.
_Motion--absolute and relative.--Uniform, accelerated, and retarded
Velocity.--The times of Ascent and Descent are equal.--Vis
inertiæ.--Friction.--Action and Reaction are equal and in
opposite directions.--Momentum defined and explained.--The Three
Great Laws of Motion._
“The table-cloth is removed,” cried Tom, as he cast a sly glance
through the open window of the dining-room.
“It is, my boy,” replied Mr. Twaddleton; “_Diffugere nives_, as the
poet has it.”
“_Et redeunt jam gramina campis_,” added Mr. Seymour, archly, as he
pointed to the green cloth with which the table was covered.
“_Et decrescentia flumina_,” continued the vicar, with a smile; “but,
psha! enough of wine and quotation. Come, let us join the children.”
Mr. Twaddleton, accompanied by Mr. and Mrs. Seymour, and Louisa, rose
from the table, and proceeded to the lawn.
“The gravitation of Tom’s ball,” said Mr. Seymour, “furnished an ample
subject for our morning’s diversion; let us try whether its other
motions will not suggest further objects of enquiry.”
“I well remember,” observed Louisa, “that Mrs. Marcet extols that
apple, the fall of which attracted the notice of Sir Isaac Newton,
above all the apples that have ever been sung by the poets: and she
declares, that the apple presented to Venus by Paris; the golden apples
by which Atalanta won the race; nay, even the apple which William Tell
shot from the head of his own son, cannot be brought into comparison
with it.”
“Well said! Mrs. Marcet,” exclaimed Mr. Seymour; “upon my word, had the
mother of mankind used but half such eloquence in praise of an apple,
we cannot wonder at its influence.”
“What honours, then,” continued Louisa, “shall we decree to Tom’s ball,
if it instructs us in the first principles of philosophy?”
“We are trifling,” observed Mr. Seymour, and so saying, he took the
ball from Tom’s hand, and rolling it along the ground, exclaimed,
“there it goes, performing, as you may perceive, two different kinds of
motion at the same time; it turns round, or revolves on its _axis_; and
goes straight forward, or, to speak more philosophically, performs a
_rectilinear_ motion.”
Tom said that he did not exactly comprehend what was meant by the
_axis_.(7) His father, therefore, informed him that the axis of a
revolving body was an imaginary line, which was itself at rest, but
about which all its other parts turned, or rotated: “But,” continued
he, “can you tell me whether you understand what is meant by the word
_motion_?”
“If he can,” exclaimed the vicar, “he is a cleverer fellow than the
wisest philosopher of antiquity, who, upon being asked the very same
question, is said to have walked across the room, and to have replied,
‘You see it, but what it is I cannot tell you.’”
“Your ancient acquaintances,” observed Mr. Seymour, “entertained some
very strange notions touching this said subject of motion. If I
remember right, Diodorus denied its very existence; but we are told
that he did not himself remain _unmoved_, when he dislocated his
shoulder, and the surgeon kept him in torture while he endeavoured to
convince him, by his own mode of reasoning, that the bone could not
have moved out of its place: we have, however, at present, nothing to
do with the ancients; the philosophers of our own times agree in
defining motion to be _‘the act of a body changing its situation with
regard to any other;’_ and you will therefore readily perceive, that
this may actually happen to a body while it remains absolutely at rest.”
“Well, that beats all the paradoxes I ever heard,” cried Tom; “a body
then may be in motion, while it is at rest?”
“Certainly,” replied Mr. Seymour; “it may be _relatively_ in motion,
while it is _absolutely_ at rest.”
“How can a body change its place,” said Louisa, “except by moving?”
“Very readily,” answered her father; “it may have its relative
situation changed with respect to surrounding objects; there is your
ball, and here is a stone, has not each of them a particular situation
with respect to the other; and by moving one, do I not change the
_relative_ situation of both?”
“I perceive your meaning,” said Tom.
“To prevent confusion, therefore, in our ideas, it became necessary to
distinguish these two kinds of motion from each other by appropriate
terms; and, accordingly, where there has been an actual change of
place, in the common meaning of the term, the motion which produced it
is termed ABSOLUTE motion; whereas, on the contrary, when the situation
has been only relatively changed, by an alteration in the position of
surrounding bodies, the motion is said to be RELATIVE.”
“Surely, papa,” said Louisa, “no person can ever mistake _relative_ for
_absolute_ motion; what then is the use of such frivolous distinctions?
When a body really moves, we can observe it in the act of changing its
place, and no difficulty can arise about the matter.”
“Nothing, my dear, is more fallacious than our vision; the earth
appears motionless, and the sun and stars _seem_ as if they revolved
round it; but it is scarcely necessary for me to inform you that our
globe is constantly moving with considerable velocity, while the sun
remains at rest.--Mr. Sadler, the famous aëronaut,” continued Mr.
Seymour, “informed me, that he was never sensible of the motion of the
balloon in any of his excursions, but that, as he ascended into the
air, the earth always appeared as if sinking beneath him, and as he
descended, as if rising to meet him.”
Mr. Twaddleton here observed, that he had heard a very curious
anecdote, when he was last in London, which fully confirmed the truth
of Mr. Sadler’s statement. “An aëronaut,” said he, “whose name I cannot
at this moment recollect, had recently published a map of his voyage,
and, instead of proceeding in any one line of direction, his track
absolutely appeared in the form of circles, connected with each other
like the links of a chain: this occasioned considerable astonishment,
and, of course, some speculation, until it was at length discovered,
that his apparent journey was to be attributed to the rotatory motion
of the balloon, which the voyager, not feeling, had never suspected.”
“And what,” asked Tom, “could have been the reason of his not having
felt the motion?”
His father explained to him, that we are only conscious of being in
motion when the conveyance, in which we are placed, suffers some
impediment in its progress. “If,” said he, “you were to close your
eyes, when sailing on calm water, with a steady breeze, you would not
perceive that you were moving: for you could not _feel_ the motion, and
you could only _see_ it by observing the change of place in the
different objects on the shore; and then it would be almost impossible,
without the aid of reason and experience, to believe that the shore
itself was not in motion, and that you were at rest; I shall, however,
be able to explain this subject more clearly by an optical toy which I
have in preparation.”
Mrs. Seymour here repeated the following passage from that interesting
novel “Anastasius,” which she observed was beautifully descriptive of
the illusive appearance to which their papa had just referred:--
“The gradually increasing breeze carried us rapidly out of the
Straits of Chio. The different objects on the
shore,--mountains,--valleys,--villages,--and steeples,--seemed in
swift succession, first advancing to meet us, then halting an instant
alongside our vessel, as if to greet us on our passage, and, lastly,
again gliding off with equal speed; till, launched into the open
main, we saw the whole line of coast gradually dissolve in distant
darkness.”
“That is indeed a beautiful and very apposite illustration,” said Mr.
Seymour; “and I think Louisa will now admit, that it is not quite so
easy, as she at first imagined, to distinguish between _Absolute_ and
_Relative_ motion.”
As the children now understood what was meant by the term _Motion_,
their father asked them whether they could tell him what produced it.
“I can make a body move by various means,” answered Tom.
“But they may all be reduced to one,” said Mr. Seymour; “viz. some
exertion which is called _Force_; thus the _force_ of my hand put your
ball in motion; while gravitation was the _force_ which made it fall to
the earth; and I must, moreover, inform you, that a body always moves
in the direction of the force which impels it, and with a velocity, or
rate of motion, which is proportional to its degree, or strength; and,
were there no other forces in action but that which originally produced
the motion, the body would proceed onwards in a right line, and with a
_uniform_ velocity for ever.”
“For ever!” exclaimed Louisa.
“Ay, my dear, _for ever_: but we will discuss that question presently;
you must first tell me whether you understand what is meant by
_uniform_ velocity.”
“I suppose that _uniform_ velocity is that which is regular, and of an
equal rate throughout.”
“Philosophers,” replied her father, “call the motion of a body
_uniform_, when it passes over equal spaces in equal times.--Now, Tom,
it is your turn to answer a question. Can you describe the meaning of
the terms _Accelerated_ and _Retarded_ motion?”
“I conclude that motion is said to be _accelerated_ when it moves every
moment quicker and quicker; and to be _retarded_ when it moves slower
and slower.”
“You are perfectly right; and gravity may either act in occasioning the
one or the other; our experiment at the well this morning afforded you
an example of gravity producing a regularly accelerated motion. I did
not fully explain the fact at the time, because I was desirous of
avoiding too many new ideas at once; we must win our way slowly and
cautiously through the mazes of philosophy: I will, however, now
endeavour to give you as clear an explanation as the subject will
allow.--It is, I think, evident, that if, at the moment you dropped the
stone from your hand, the force of gravity could have been suspended,
it would have descended to the bottom of the well with a uniform
velocity; because there could have been nothing either to accelerate or
retard its motion. But this was not the case, for the power of gravity
was in constant operation; and, if you keep this fact in mind, you will
readily understand how the velocity became accelerated: for, suppose
the impulse given by gravity to the stone, during the first instant of
its descent, be equal to _one_, the next instant we shall find that an
additional impulse gives the stone an additional velocity equal to
_one_, so that the accumulated velocity is now equal to two; the
following instant, again, increases the velocity to _three_, and so on
till the stone reaches the bottom.”
Mr. Twaddleton observed, the fact might be shortly expressed by saying,
that “the effects of preceding impulses must be added to subsequent
velocities.”
Mr. Seymour then remarked that the same explanation would apply to
_retarded_ velocity. “If,” said he, “you throw a stone perpendicularly
upwards, the velocity will be as much _retarded_, as it was in the
other case _accelerated_, by gravity; the consequence of which is, that
it will be exactly the same length of time ascending that it was
descending.”
“I should have thought the very reverse,” cried Louisa, “and that it
would have fallen quicker than it rose.”
“You have forgotten to take into account the force with which the stone
is projected upwards, and which is destroyed by gravity before it
begins to descend.”
“Certainly,” answered Louisa; “but the force given to a stone in
throwing it upwards, cannot always be equal to the force of gravity in
bringing it down again; for the force of gravity is always the same,
while the force given to the stone is entirely optional. I may throw it
up gently or otherwise, as I please.”
“If you throw it gently,” said her father, “it will not rise high, and
gravity will soon bring it down again; if you throw it with violence,
it will rise much higher, and gravity will be longer in bringing it
back again to the ground. Suppose, for instance, that you throw it with
a force that will make it rise only sixteen feet; in that case, you
know, it will fall in one second of time. Now it is proved by
experiment, that an impulse requisite to project a body sixteen feet
upwards, will make it ascend that height in one second of time; here,
then, the times of ascent and descent are equal. But, supposing it be
required to throw a stone twice that height, the force must be
proportionally greater. You see, then, that the impulse of projection,
in throwing a body upwards, is always equal to the action of the force
of gravity during its descent; and that it is the greater or less
distance to which the body rises that makes these two forces balance
each other.”
“Thank you, dear papa, for the pains you have taken in explaining this
subject to us.”
“Nay,” replied Mr. Seymour, “bestow your thanks upon those to whom they
are more justly due; Mrs. Marcet is entitled to the merit of this
explanation; for I obtained it from her ‘Conversations.’ Before I quit
this subject, I would just observe that, when we come to the
consideration of the bow and arrow, you will, by the application of the
law I have endeavoured to expound, be enabled to ascertain the height
to which your arrow may ascend, with the same facility as you
discovered the depth of the well: for, since the times of ascent and
descent are equal, you have only to determine the number of seconds
which intervene between the instant at which the arrow quits the bow to
that at which it falls to the ground, and halving them, to make the
usual calculation.--But let us proceed to another subject. Roll the
ball hither, Tom; roll the ball hither, I say! you stand as if you
thought it would advance to us of its own accord.”
“I know a little better than that, too,” cried Tom; “no body can move
without the application of some force.”
“Nor stop, either,” added Mr. Seymour, “when it is once in motion; for
matter is equally indifferent to both rest and motion.”
“And yet, papa,” cried Louisa, “unfortunately for your assertion, the
ball stopped just now, and I am sure that no force was used to make it
do so.”
“And pray, Miss Pert, why are you so sure that no force was opposed to
its progress? I begin to fear that my lesson has been thrown away upon
you, or you would not, surely, have concluded so falsely.”
The vicar here interposed, observing that, simple as the question might
appear to those who had studied it, the fact was so contrary to
everything that passed before us, that Mr. Seymour ought not to feel
any surprise at the scepticism of his daughter; he begged to remind him
that the truth, apparent as it doubtless now was, lay hid for ages
before the sagacity of Galileo brought it to light.
Mr. Seymour admitted the justice of this remark, and proceeded in his
explanation.
“I think,” said he “you will readily allow that matter cannot, in
itself, possess any power of changing its condition: it can, therefore,
no more destroy, than it can originate its own motion; when it is at
rest, it must ever remain so, unless some force be applied that can
impart to it activity; and, when once in motion, it must continue to
move until some counteracting force stops it. To believe otherwise you
must suppose that matter possesses in itself a power to alter its
condition, which is perfectly absurd.”
“And yet,” said Tom, “when I see my ball or marble stop of its own
accord, how can you blame me for believing it possible?”
“Your difficulty arises from your ignorance of the existence of certain
forces which act upon the rolling ball or marble. Its progress, as it
rolls along, is impeded and ultimately stopped by the rubbing, or
friction, occasioned by its passage over the ground; and this will be
greater or less, according to the degree of roughness of the surface;
if it be small, the ball will continue for a longer time in motion; you
must have observed, that your marble has always rolled much farther on
a smooth pavement than on a rough gravel walk.”
“Certainly,” said Tom, “and I well remember, that when we played at
_ring-taw_ last winter on the ice, we were obliged, for this very
reason, to extend the usual boundaries.”
“Is it not evident, then, that the motion of a body is stopped by some
opposing force; and that, if this could be entirely removed, the body
would continue to move for ever?”
“What a provoking thing this friction is,” said Tom, “it is always
interfering with our experiments.”
“Provoking, is it? I fancy,” said Mr. Seymour, “that you would be much
more provoked by the loss of it: without it, you could not walk, nor
even hold an object in your hands; and yet everything around you would
be in perpetual motion, performing one universal and interminable
dance.”
“I can readily understand, from what you have said, that, if friction
were removed, motion might continue; but pray how is it that we should
be unable to walk, or to hold anything in our hands?” enquired Louisa.
“It is the friction of the ground which, at every step we take,
prevents the foot from sliding back, and thus enables us to push the
body forwards. Everybody must have felt how difficult it is to walk on
ice, where the friction is only diminished, not entirely removed,”
answered her father; “and as to holding any object,” continued he, “it
is the friction of the body to which we apply our hands that enables us
to hold it firmly.”
“To be sure,” exclaimed the vicar; “why, my boy, you must surely
remember, that in ancient combats it was the custom to rub the body
with oil, that the adversary might not be able to keep his grasp.”
“Well,” said Tom, “our houses, I suppose, would remain firm, and we
might sit quietly in our chairs, at all events.”
“Not so,” replied Mr. Seymour, “for even granting that you had houses
and chairs, which, without the existence of friction would never exist,
the stability of the structures could never be secured; the slightest
breath would be sufficient to make the stones or bricks slide off from
each other, and to reduce your dwellings into dancing ruins.”
Tom and Louisa, after some farther discussion, both admitted the
justness of the argument; but, at the same time, would have been better
satisfied if the fact could have been proved by actual experiment. Mr.
Seymour told them that the perpetual revolution of the earth and
heavenly bodies, where no friction whatever existed, afforded a proof
which ought to satisfy them; and, especially, since it agreed with
those views which were proved to be true by an examination of what took
place on the surface of our own globe.
We will, therefore, with the permission of our readers, consider this
point as settled, and proceed with the young philosophers to the
investigation of some other topics connected with the doctrine of
motion.
“Since a body at rest,” said Mr. Seymour, “can only be set in motion,
or, when in motion, be brought to rest, by the impression of some
force, it must follow, that it can only move in the direction in which
such a force may act; and, moreover, that the degree of motion, or the
_velocity_, must, other things being equal, be in proportion to the
degree of force used.”
“Why, truly,” cried the vicar, “my young friends must of necessity
admit that fact; for the body, not having any will of its own, as you
say, must needs, if it move at all, go the road it is driven.”
“Yes,” added Mr. Seymour, “and it must go with a velocity in proportion
to the force with which it is driven.”
“Doubtless, doubtless,” cried the vicar, “you admit that also; do you
not, my young friends and playmates?”
It is hardly necessary to state, that the children instantly assented
to these propositions. The vicar had placed them in so clear and
popular a point of view, as to be intelligible to the lowest capacities.
“With these admissions, then, my dear children,” said their father, “I
shall have but little difficulty in convincing you of the truth of the
other laws by which the direction of moving bodies is governed. At
present, however, it is not my intention to enter upon this subject;
you have some preliminary knowledge to acquire before you can
understand what is termed the _Composition and Resolution of Forces_.”
“I shall not easily forget,” said Louisa, “that matter is perfectly
passive, and that it can neither put itself in motion when at rest, nor
stop itself when in motion.”
“This indifference to rest or motion,” replied Mr. Seymour, “has been
termed the _Vis Inertiæ_ of matter.”
“A very objectionable term,--a very puzzling expression,” exclaimed the
vicar;--“to denote a mere state of passive indifference by the term
_Vis_, or power, does appear to me, who have been in the habit of
connecting words with ideas, as excessively absurd.”
“I allow,” said Mr. Seymour, “that the simple word _Inertia_ would have
been more correct; but we are bound to receive an expression which has
been long current. I suppose, however, you know that the addition of
_Vis_ originated with Kepler, who, like my boy Tom, could not help
thinking that the disposition of a body to maintain its motion, or
state of rest, indicated something like power; but we will not waste
our time upon verbal disquisitions. It is clear, that matter, at rest,
resists being put in motion; the degree of that resistance is always in
proportion to the degree of force applied to put it in motion; or, to
speak more philosophically, that _Action and Reaction are equal, and in
opposite directions_.”
“You, surely, do not mean to say,” exclaimed Tom, “that if I strike my
marble, the marble strikes my hand, with the same force in return?”
“Precisely; that is my meaning.”
“What!” cried Louisa, “if a man strikes another on the face with his
hand, do you seriously maintain that both parties suffer the same pain?”
“Oh, no, no,” said Tom, “papa can never intend to say that; I am quite
sure, if it were the case, Mr. Pearson would not be so fond of boxing
our ears.”
Mr. Seymour answered this question, by observing that, if the hand
possessed the same degree of feeling as the face, they would both
suffer equally under the conflict. “If,” continued he, “you strike a
glass bottle with an iron hammer, the blow will be received by the
hammer and the glass; and it is quite immaterial whether the hammer be
moved against the bottle at rest, or the bottle be moved against the
hammer at rest, yet the bottle will be broken, though the hammer be not
injured; because the same blow which is sufficient to shiver the glass
is not sufficient to break or injure a lump of iron. In like manner,
the blow that is sufficient to pain your sensitive face, and make your
ears tingle, will not occasion the least annoyance to the obtuse hand
of your preceptor. The operation of this law,” continued Mr. Seymour,
“will be exemplified in every step of our progress. When the marble, as
it rolls along, strikes any obstacles, it receives, in return, a
corresponding blow, which will be found to influence its subsequent
direction. The peg of the top, as it rubs on the ground, is as much
influenced by the friction, as if a force were actually applied to it
when in a state of rest; and when we consider the forces by which the
kite is made to ascend into the air, you will learn, from the same law,
the nature of that advantage which you derive from running with it.”
The vicar observed that the subject of _Momentum_ might be introduced,
and advantageously explained, upon this occasion.
“Momentum,” said Tom; “and pray what is that?”
“It is a power,” replied his father, “intimately connected with motion;
and, therefore, as your friend, the vicar, justly remarks, may be very
properly introduced before we quit that subject.--It is the force with
which a body in motion strikes against another body.”
“That,” observed Tom, “must of course depend upon the velocity of the
body’s motion.”
“Undoubtedly, my dear; the quicker a body moves, the greater must be
the force with which it would strike against another body; but we also
know that the heavier a body is, the greater also will be its force; so
that _momentum_, you perceive, must have a relation to both these
circumstances, viz. velocity, and weight; or, to speak more correctly,
_the momentum of a body is composed of its quantity of matter,
multiplied by its quantity of motion_: for example, if the weight of a
body be represented by the number 3, and its velocity also by 3, its
_momentum_ will be represented by 3 x 3 = 9; so that, in producing
momentum, increased velocity will always compensate for deficiency of
matter, and a light body may thus be made a more effective force than a
heavy one, provided that its velocity be proportionally increased;
thus, a small ball weighing only _two pounds_, and moving at the rate
of _five hundred feet_ in a second, will produce as much effect as a
cannon ball of _ten pounds_ in weight, provided it moved only at the
rate of _one hundred feet_ in the same time.”
“Let me see,” cried Tom, “whether I understand your statement. We must
multiply, as you say, the weight by the velocity; the weight of the
small ball you state at two pounds, and it travels at the rate of five
hundred feet in a second; then its momentum must be a thousand. The
weight of the great ball is ten pounds, its velocity only a hundred
feet, then its momentum must also be a thousand; because, in both
cases, the sums multiplied into each other will give the same product.”
“Exactly: and thus you perceive that the small ball becomes an exact
balance to the larger one; the first making out in motion what it
wanted in matter, while the latter makes out in matter what it wanted
in motion. I wish you to keep this law of _Momentum_ in your
remembrance; upon it depends the action of all the _mechanical
powers_(8), as they are termed.”
“I have heard,” said Louisa, “that a feather might be made to produce
as much havoc as a cannon shot, if you could give it sufficient
velocity.”
“Unquestionably: but there is a practical difficulty in the attempt,
from the resistance of the air, which increases, as you have already
seen in the experiment of the paper and penny-piece (p. 30), as the
weight of a body decreases. Were it not for this resistance of the air,
a hailstone falling from the clouds would acquire such a momentum, from
its accelerated velocity, as to descend like a bullet from a gun, and
destroy every thing before it; even those genial showers which refresh
us in the spring and summer months, would, without such a provision,
destroy the herbage they are so well calculated to cherish. Had the
elephant possessed the mobility of the beetle, it would have overturned
mountains. From this view of the subject of Momentum,” continued Mr.
Seymour, “you will easily understand why the immense battering rams,
used by the ancients, in the art of war, should have given place to
cannon balls, of but a few pounds in weight. Suppose, for example, that
the battering ram of Vespasian weighed 100,000 pounds, and was moved,
we will admit, with such a velocity, by strength of hands, as to pass
through 20 feet in one second of time, and that this was found
sufficient to demolish the walls of Jerusalem, can you tell me with
what velocity a 32-pounder must move to do the same execution?”
“I will try,” said Tom, as he took out his pencil and pocket-book, to
make the calculation. “The momentum of the battering ram must be
estimated by its weight, multiplied into the space passed over in a
second of time; which is 100,000 multiplied by 20; that will give
2,000,000. Now, if this momentum, which must also be that of the cannon
ball, be divided by the weight of the ball, it will give the velocity
required, which I make out to be 62,500 feet.”
“Admirably calculated,” said Mr. Seymour: “and I will take care, my
dear Tom, that your intelligence shall be suitably rewarded.”
Mr. Twaddleton here observed, that he thought “his young friends and
playmates” must have received, for that day, as much philosophy as they
could conveniently carry away without fatigue. Mr. Seymour concurred in
this observation; and the more readily, as the path they had to travel
was rugged, and beset with difficulties. “I will, therefore,” said he,
“not impose any farther burthen upon them; but I will assist them in
tying, into separate bundles, the materials which they have collected
in their progress, in order that they may convey them away with greater
ease and security. Know then, my dear children,” said the affectionate
parent, “that you have this day been instructed in the three great Laws
of Motion, viz.
I. _That every body will continue in a state of rest, until put
into motion by some external force applied to it, and if that
force be single, the motion so produced will be rectilinear, i.e.
in the direction of a straight line._
II. _Change of motion is always proportional to the moving force
impressed, and is always made in the direction of the right line
in which the force acts._
III. _Action and Reaction are equal in equal quantities of matter,
and act in contrary directions to each other.”_
[Illustration: Two men on the ice, falling in opposite directions.]
------------------------------------------------------------------------
CHAPTER IV.
_A sad accident turned to a good account.--One example worth a
hundred precepts.--The Centres of Magnitude and Gravity.--The
Point of Suspension.--The Line of Direction.--The stability of
bodies, and upon what it depends.--Method of finding the centre
of gravity of a body.--The art of the Balancer explained and
illustrated.--Various balancing toys._
Just as Mr. Seymour was, on the following morning, stepping upon the
lawn, with the intention of joining his children, Rosa and Fanny both
made their appearance completely drenched with water, and dripping like
mermaids.
“Heyday!” exclaimed their father, “how has this misfortune happened?”
“Do not be angry, papa,” said Tom; “indeed, indeed, it was an accident.
Fanny, observing the water-cart in the garden, had just begun to wheel
it forward, when the water rushed over her like a wave of the sea, and,
upon stopping the cart, it flew over with equal force on the opposite
side, and deluged poor Rosa, who was walking in front of it.”
“Well, well, lose no time in changing your clothes, and meet me again
in half an hour.”
At the appointed time the children reassembled on the lawn.
“And so then,” said their father, “I perceive that my philosophical
lesson of yesterday has been entirely lost upon you.”
The children were unable to comprehend the meaning of this rebuke; but
Mr. Seymour proceeded:--
“I trust, however, that the accident of this morning will serve to
impress it more forcibly upon your memory: one example is better than a
hundred precepts.”
Tom was more puzzled than ever.
“You have met with an accident; I will endeavour to convert it into a
source of instruction, by showing you how the principles of natural
philosophy may be brought to bear upon the most trivial concerns of
life. You learned yesterday, that a body at rest offers a resistance to
any force that would put it in motion, and that, when in motion, it
equally opposes a state of rest; now let us apply this law for the
explanation of the accident that has just befallen you. The butt was
full of water; when you attempted to wheel it forward, the water
resisted the motion thus communicated to the vessel, and from its _vis
inertiæ_, or effort to remain at rest, rose up in a direction contrary
to that in which the vessel moved, and consequently poured over; by
this time, however, the mass of fluid had acquired the motion of the
cart, when you suddenly stopped it, and the water in endeavouring to
continue its state of motion, from the same cause that it had just
before resisted it, rose up on the opposite side, and thus deluged poor
Rosa.”
Louisa was quite delighted with this simple and satisfactory
application of philosophy, and observed, that she should not herself
mind a thorough soaking, if it were afterwards rewarded by a scientific
discovery.
“I will give you, then, another illustration of the same law of
motion,” said Mr. Seymour, “which, instead of explaining an accident,
may, perhaps, have the effect of preventing one. If, while you are
sitting quietly on your horse, the animal starts forward, you will be
in danger of falling off _backward_; but if, while you are galloping
along, it should stop suddenly, you will inevitably be thrown _forward_
over the head of the animal.”
“I clearly perceive,” said Louisa, “that such would be my fate under
the circumstances you state.”
“Now, then, my dear children, since our friend the vicar cannot attend
us at present, suppose we retire to the library, where I have an
interesting experiment to perform, and a new toy ready for your
inspection.”
In compliance with their father’s wishes, the children cheerfully
returned to the library, when Mr. Seymour presented Louisa with a
BANDILOR. Most of our readers are, doubtless, acquainted with this
elegant toy. It consists of two discs of wood, united to each other by
a small axis, upon which a piece of string is affixed. When this string
is wound round the axis, and the bandilor is suffered to run down from
the hand, the end of the string being held by a loop on the fore
finger, its momentum winds up the string again, and thus it will
continue for any length of time to descend from, and ascend to, the
hand. It affords a good example of the operation of _vis inertiæ_, or
what may, with equal propriety, be termed _the momentum of rotatory
motion_. Its action may be compared to that of a wheel, which, running
down a hill, acquires sufficient momentum to carry it up another. There
are several toys which owe their operation to the same principle, of
which we may particularize the windmill, whose fliers are pulled round
by a string affixed to the axis of the sails. In playing with the
bandilor, a certain address is required to prevent the sudden check
which the toy would otherwise receive when it arrived at the end of the
string, and which would necessarily so destroy its momentum as to
prevent its winding itself up again. Mr. Seymour now informed his young
pupils that he had an experiment to exhibit, which would further
illustrate, in a very pleasing manner, the truth of the doctrine of
_vis inertiæ_. He accordingly inverted a wine-glass, and placed a
shilling on its foot; and, having pushed it suddenly along the table,
the coin flew off, towards the operator, or in a direction opposite to
that in which the glass was moving. He then replaced the shilling, and
imparted to the glass a less sudden motion; and, when it had acquired
sufficient velocity, he checked it, and the coin darted forward,
leaving the glass behind it.
Louisa, upon witnessing this experiment, observed that she felt
satisfied of the correctness of her father’s statement, when he told
her that, if the horse suddenly started forward, when she was at rest,
she would be thrown off behind, and that if it should suddenly stop on
the gallop, she would be precipitated over its head. The children now
arranged themselves around the table, in order to consider several
curious toys which Mr. Seymour had collected for the purpose of
explaining the nature of the _Centre of Gravity_.
“But, in the first place,” said Mr. Seymour, “can you tell me, Tom,
what is meant by _The Centre of Gravity_?”
“Its central point,” answered the boy.
“Certainly not; the central point is termed its centre of _magnitude_,
not that of gravity; and it is only when a body is of uniform density,
and regular figure, that these centres of magnitude and gravity
coincide, or fall in the same spot.”
“I now remember,” cried Tom, “that the centre of gravity is that point,
about which all the parts of a body exactly balance each other.”
“Now you are right; it is, in other words, that point in which the
whole weight, or gravitating influence, of a body is, as it were,
condensed or concentrated, and upon which, if the body be freely
suspended, it will rest with security; and consequently, as long as
this centre is supported, the body can never fall; while, in every
other position, it will endeavour to descend to the lowest place at
which it can arrive.”
“Have all bodies, whatever may be their shape, a centre of gravity?”
asked Louisa.
“Undoubtedly.”
“And you say,” continued Louisa, “that every body will fall, if this
point is not supported.”
“Infallibly. And now, Tom,” said Mr. Seymour, “can you tell me what is
meant by the _line of direction_?”
The young philosopher was unable to answer this question, and his
father, therefore, informed him that, if a perpendicular line were
drawn from the centre of gravity of a body to the centre of the earth,
such a line would be termed the _line of direction_; along which every
body, not supported, endeavours to fall; and he was also informed that,
if this said line fell within the base of a body, such a body was sure
to stand; but never otherwise.
Louisa observed that she was not quite sure she understood her papa’s
meaning, and therefore begged for further explanation.
[Illustration: Fig. 10. Overloaded cart with plumb line hanging from
its center of gravity to outside its base of support.]
[Illustration: Fig. 11. Properly loaded cart with plumb line hanging
from its center of gravity to inside its base of support.]
“I will exemplify it then,” replied Mr. Seymour, “by a drawing. Fig. 10
represents a load of stones in a cart moving upon the sloping road
C D E; this load, being low down in the cart, B will represent its
centre of gravity, and B F its line of direction, which, you perceive,
falls much within the supporting or lower wheel G; and there cannot,
therefore, be any danger of such a cart being overturned; but in fig.
11, the centre of gravity is raised from its former position to H, and
H I is now the line of direction; which, falling without the base, or
wheel K, the load will not be supported, and must consequently fall.
These figures,” added Mr. Seymour, “will also explain a fact which you
must have frequently observed, that a body is stable or firm in
proportion to the breadth of its base; hence the difficulty of
sustaining a tall body, like a walking stick, upon its narrow base; of
that of balancing a hoop upon its edge, or a top upon its point; while,
on the contrary, it is almost impossible to upset the cone or the
pyramid, since, in the latter cases, the _line of direction_ falls
within the middle of the base, the centre of gravity of the body being
necessarily low.”
“I suppose,” observed Louisa, “that this is the reason why carriages,
when too much loaded, are so apt to upset.”
“Say, when too much loaded on their _tops_, and you will be right. As
you now, I trust, understand this part of the subject, let us proceed a
step farther: if you take any body, with a view to suspend it, is it
not evident, that if it be suspended by that point in which the centre
of gravity is situated, it must remain at rest in _any_ position
indifferently?”
“I thought,” said Tom, “we had already settled that question.”
“True, my dear boy; but there is another question of great importance
arising out of it, and which you have not yet considered: tell me,
should the body be suspended on any other point, in what position it
can rest?”
“I do not exactly understand the question.”
“There are,” replied his father, “only two positions in which it could
rest, either where the centre of gravity is exactly _above_, or exactly
_below_, the point of suspension; so that, in short, this point shall
be in the _line of direction_. Where the point of suspension is _below_
the centre of gravity, it is extremely difficult to balance or support
a tall body by such a method, because the centre of gravity is always
endeavouring to get under the point of support. Look at this diagram,
and you will readily comprehend my meaning. K is the centre of gravity
of the diamond-shaped figure, which may be supported, or balanced, on a
pin passing through it at M, as long as the centre of gravity K is
immediately over the point of suspension M: but if that centre is
removed in the slightest degree, either to the right or left of its
place K, the body will no longer retain its erect position I K L, but
it will revolve upon M, and place itself in the situation indicated by
the dotted lines beneath the point M: and its centre of gravity will
now be removed to N, directly _under_ M, and in the line K L, which, as
you well know, is the line of direction. Have I rendered myself
intelligible?”
[Illustration: Fig. 12. Diagram of a kite’s center of gravity.]
“I understand it perfectly,” answered Tom.
“And do you also, my dear Louisa?”
Louisa’s answer was equally satisfactory, and Mr. Seymour went on to
state that the information they had now acquired would enable them to
ascertain the situation of the centre of gravity of any plane surface
which was portable, notwithstanding it might possess the utmost
irregularity of shape.
“You shall, for example,” continued he, “find the centre of gravity in
your kite.”
“I cannot say,” observed Tom, “how I should set about it.”
“Well, fetch your kite, and I will explain the method.”
Tom soon produced it, and the tail having been removed, Mr. Seymour
proceeded as follows:--
[Illustration: Fig. 13. Kite viewed right side up.]
“I now,” said he, “suspend the kite by the loop at its bow, and since
it is at rest, we know that the centre of gravity must be exactly below
the point of suspension; if, therefore, we draw a perpendicular line
from that point, which may be easily done by a plumb-line, with a
weight attached to it, such a line will represent the _line of
direction_ (as indicated by A B in fig. 13)”.
“It is clear enough,” said Tom, “that the centre of gravity must lie in
the line A B, but how are we to find in what part of it?”
“By suspending the kite in another direction,” answered Mr. Seymour,
who then hung it up in the position represented at fig. 14, “and then
by drawing another perpendicular from the new point of suspension.”
[Illustration: Fig. 14. Kite viewed at a diagonal.]
“The centre of gravity,” said Louisa, “will in that case be in the line
_c d_, as it was before in that of _a b_.”
“In both the lines!” exclaimed Tom, with some surprise; “it cannot be
in two places.”
“And therefore,” added Mr. Seymour, “it must be in that point in which
the lines meet and cross each other:” so saying, he marked the spot _g_
with his pencil, and then told his little scholars, that he would soon
convince them of the accuracy of the principle. He accordingly placed
the head of his stick upon the pencil mark, and the kite was found to
balance itself with great exactness.
“True, papa,” said Tom, “that point must be the centre of gravity, for
all the parts of the kite exactly balance each other about it.”
“It is really,” observed Louisa, “a very simple method of finding the
centre of gravity.”
“It is,” said Mr. Seymour; “but you must remember that it will only
apply to a certain description of bodies: when they are not portable,
and will not admit of this kind of examination, their centres of
gravity can only be ascertained by experiment or calculation, in which
the weight, density, and situation of the respective materials must be
taken into the account. Having proceeded thus far, you have next to
learn that the centre of gravity is sometimes so situated as not to be
_within_ the body, but actually at some distance from it.”
“Why, papa!” exclaimed Tom, “how can that possibly happen?”
“You shall hear. The centre of gravity, as you have just said, is that
point about which all the parts of a body balance each other: but it
may so happen that there is a vacant space at this point. Where, for
example, is the centre of gravity of this ring? Must it not be in the
space which the ring encircles?”
“I think it must,” said Tom; “and yet how can it be ever supported
without touching the ring?”
[Illustration: One ring supported by a string, and another ring
balanced on a finger.]
“That point cannot be supported,” answered his father, “unless the ring
be so held that the line of direction shall fall within the base of the
support, which will be the case whether you poise the ring on the tip
of your finger, or suspend it by a string, as represented in the
figures which I have copied from the ‘Conversations on Natural
Philosophy.’ I need scarcely add, that it will be more stably supported
in the latter position, because the centre of gravity is below the
point of suspension; whereas in the former the base is extremely
narrow, and it will, consequently, require all the address of the
balancer to prevent the centre of gravity from falling beyond it. As
you are now in possession of all the leading principles upon which the
operations of the centre of gravity depend, I shall put a few practical
questions to you, in order that I may be satisfied you understand them.
Tell me, therefore, why a person who is fearful of falling, as, for
instance, when he leans forward, should invariably put forward one of
his feet, as you did the other day, when you looked into Overton well?”
“To increase his base,” answered Tom; “whenever I lean greatly forward,
I should throw the line of direction beyond it, did I not at the same
instant put out one of my feet, so as to extend my base, and thus to
cause the line to continue within it.”
“Rightly answered; and, for the same reason, a porter with a load on
his back leans forward, to prevent his burthen from throwing the line
of direction out of the base behind. So the horse, in drawing a heavy
weight, instinctively leans forward, in order to throw the whole of his
weight as a counterbalance; and yet,” observed Mr. Seymour, “we are in
the habit of ignorantly restraining him by a bearing rein, in
consequence of which he has to call in the aid of his muscles, by which
a very unnecessary exhaustion of strength is produced. Thus is it that
German and French horses draw heavy weights with apparently greater
ease to themselves, because the Germans tie a horse’s nose _downwards_,
while the French, more wisely, leave them at perfect liberty. But to
proceed. Did you ever observe the manner in which a woman carries a
pail of water?”
“To be sure,” said Tom; “she always stretches out one of her arms.”
“The weight of the pail,” continued Mr. Seymour, “throws the centre of
gravity on one side, and the woman, therefore, stretches out the
opposite arm, in order to bring it back again into its original
situation; did she not do this, she must, like the English draught
horses, exert her muscles as a counteracting force, which would greatly
increase the fatigue of the operation: but a pail hanging on each arm
is carried without difficulty, because they balance each other, and the
centre of gravity remains supported by the feet.”
“I see,” said Louisa, “that all you have said about the woman and her
pail must be true; but how could she have learned the principle which
thus enabled her to keep the centre of gravity in its proper place?”
“By experience. It is very unlikely that she should ever have heard of
such a principle, any more than those people who pack carts and
waggons, and yet make up their loads with such accuracy as always to
keep the line of direction in, or near, the middle of the base. But to
proceed to another example--have I not frequently cautioned you against
jumping up suddenly in a boat? Can you tell me upon what principle such
an operation must be attended with danger?”
“I suppose,” said Tom, “for the very same reason that a waggon is more
likely to be overturned when its top is too heavily laden; it would
elevate the centre of gravity, and thereby render the line of direction
liable to be thrown beyond the base, and so upset the boat.”
Mr. Seymour observed, that after this lesson he thought the balancing
which Tom and Louisa had witnessed at Astley’s theatre, last year,
would cease to appear so miraculous. Louisa declared that she had now
discovered the whole mystery.
“You have doubtless perceived,” said her father, “that the art entirely
consists in dexterously altering the centre of gravity upon every new
position of the body, so as constantly to preserve the line of
direction within the base. Rope-dancers effect this by means of a long
pole, the ends of which are loaded by weights, and which they hold
across the rope. If you had paid sufficient attention to their
movements, you must have perceived how steadily they fixed their eyes
on some object near the rope, so as to discover the slightest deviation
of their centre of gravity to one or the other of its sides, which they
no sooner detect, than they instantly rectify it by a countervailing
motion of their pole, and are thus enabled to preserve the line of
direction within the narrow base. This very same expedient is
frequently practised by ourselves; if we slip or stumble with one foot,
we naturally extend the opposite arm, making the same use of it as the
rope-dancer does of his pole. Many birds, also, by means of their
flexible necks, vary the position of their centre of gravity in the
same manner. When they sleep, they turn it towards the back, and place
it under the wing, in order to lay the greatest weight on the point
above the feet.”
“What an interesting subject this is,” cried Louisa, “and how many
curious things it is capable of explaining!”
“Indeed is it; and I shall take an opportunity of pointing out several
specimens of art (9) which are indebted for their stability to the
scientific application of the principle we have been considering;--but
I have now a paradox for you, Tom.”
“Let us hear it, papa.”
“How comes it that a stick, loaded with a weight at the upper
extremity, can be kept in equilibrio, on the point of the finger, with
much greater ease than when the weight is near the lower extremity, or,
for instance, that a sword can be balanced on the finger much better
when the hilt is uppermost?”
“That is indeed strange. I should have thought,” replied Louisa, “that
the higher the weight was placed above the point of support, the more
readily would the line of direction have been thrown beyond the base.”
“In that respect you are perfectly right; but the balancer will be able
to restore it more easily in one case than in the other; since, for
reasons which you will presently discover, the greater the circle which
a body describes in falling, the less will be its tendency to fall.
Look at the sketch which I have prepared for the explanation of this
fact, and I think you will readily comprehend the reason of it.
[Illustration: Man balancing a sword in each hand, hilt up in one, hilt
down in other, showing arc of centres of gravity for each.]
“When the weight is at a considerable distance from the point of
support, its centre of gravity, in deviating either on one side or the
other from a perpendicular direction, describes a larger circle, as at
_a_, than when the weight is very near to the centre of rotation or the
point of support, as at _b_. But, in a large circle, an arc of any
determinate extent, such as an inch, for example, describes a curve
which deviates much less from the perpendicular than if the circle were
less; as may be seen by comparing the positions of the sword at _d_ and
_e_; and the sword at _d_ will not have so great a tendency to deviate
farther from the perpendicular, as that at _e_; for its tendency to
deviate altogether from the perpendicular is greater, according as the
tangent to that point of the arc, where it happens to be, approaches
more to the vertical position. You see then that it is less difficult
to balance a tall, than a shorter pole; and it is for the same reason
that a person can walk with greater security on high than on low
stilts.”
“That is very clear,” said Louisa, “although, before your explanation,
I always associated the idea of difficulty with their height.”
“I suppose,” added Tom, “that the whole art of walking on stilts may be
explained by the principles you have taught us.”
“Undoubtedly it may; for the equilibrium is preserved by varying the
position of the body, and thus keeping the centre of gravity within the
base.”
“It must be a great exertion,” observed Louisa.
“Before custom has rendered it familiar; after which, there is no more
fatigue in walking on stilts, than in walking on our feet. There is a
district in the south of France, near Bourdeaux, called the Desert of
Landes, which runs along the sea coast between the mouths of the Adour
and Gironde, where all the shepherds are mounted on stilts; on which
they move with perfect freedom, and astonishing rapidity; and so easily
does habit enable them to preserve their balance, that they run, jump,
stoop, and even dance, with ease and security.”
“How very odd!” said Tom; “what can be their motive for such a strange
habit?”
“Its objects,” replied his father, “are important: to keep the feet out
of the water, which, during the winter, is deep on the sands; and to
defend them from the heated sand during the summer; in addition to
which, the sphere of vision over so perfect a flat is materially
increased by the elevation, and the shepherds are thus enabled to see
their flocks at a much greater distance.[9] They cannot, however, stand
perfectly still upon their stilts, without the aid of a long staff,
which they always carry in their hands; this guards them against any
accidental trip, and, when they wish to be at rest, forms a third leg
that keeps them steady.”
“I suppose,” said Louisa; “that the habit of using these stilts is
acquired while they are very young.”
“It is, my dear: and it appears that, the smaller the boy is, the
higher are his stilts; a fact which affords a practical proof of the
truth of what I have just stated.”
“The stork is said, in my work on Natural History, to be always walking
on stilts,” said Louisa; “and yet it does not appear to fatigue him.”
“That is very true,” replied the father; “but you must remember, that
nature has furnished the bird with a provision, by which the legs are
kept extended without any exertion of the muscles, in the manner of
certain springs; a structure which enables it to pass whole days and
nights on one foot, without the slightest fatigue. If you will visit
the cook the next time she trusses a fowl, you will at once perceive
the nature and utility of this structure; upon bending the legs and
thighs up towards the body, you will observe that the claws close of
their own accord; now, this is the position of the limbs in which the
bird rests upon its perch, and in this position it sleeps in safety,
for the claws do their office in keeping hold of the support, not by
any voluntary exertion, but by the weight of the body drawing the
strings tight.”
“But, papa,” said Tom, “I have yet some more questions to ask you on
the subject of balancing. I am not at all satisfied about many of the
tricks that we saw last year; indeed, I cannot believe, that many of
those astonishing feats can be explained by the rules you have just
given us.”
“I very well know to what you allude,” replied Mr. Seymour. “Many
singular deceptions are certainly practised by removing the centre of
gravity from its natural into an artificial situation, or by disguising
its place; thus, a cylinder placed upon an inclined surface may be made
to run _up_, instead of _down_ hill. I can even appear to balance a
pailful of water on the slender stem of a tobacco-pipe: but I shall be
enabled to explain the nature of these deceptions by some toys which I
have provided for your amusement, and which I must say you are fully
entitled to possess, as a reward for the clear and satisfactory manner
in which you have this day answered my questions. But see! here comes
Mr. Twaddleton: he would really seem to possess an instinct that always
brings him to the Lodge whenever I am preparing some amusement for you.”
The vicar smiled as he entered the room, but, unwilling to interrupt
the lesson, he placed his fore finger on his lip, and, with a
significant nod, silently took a seat at the table. The children
laughed aloud at this cautious demeanour; and Tom exclaimed, “Why, Mr.
Twaddleton, our lesson is over, and we are going to receive some new
toys as a reward.”
“I have here,” said Mr. Seymour, as he opened a large wooden box, “a
collection of figures, which will always raise themselves upright, and
preserve the erect position; or regain it, whenever it may have been
disturbed.”
He then arranged these figures in battalion on the table, and striking
them flat by drawing a rod over them, they immediately started up
again, as soon as it was removed. “These figures,” continued he, “were
bought at Paris some years ago, under the title of _Prussians_.”
“I declare,” exclaimed the vicar, “they remind me of the rebellious
spirits whom Milton represents as saying that ascent is their natural,
and descent their unnatural, motion.”[10]
“I have seen skreens similarly constructed,” said Mrs. Seymour, “which
always rose up, of themselves, upon the removal of the force that had
pressed them down.”
“I will explain their principle,” said Mr. Seymour.
“Suppose we first examine the construction of the figure,” observed the
vicar. “Bless me! why it is like Philotus the poet, who was so thin and
light, that lead was fastened to his shoes to prevent his being blown
away.”
[Illustration: Toy soldier mounted on the flat part of a hemisphere.]
“The figure,” said Mr. Seymour, “is made of the pith of the elder-tree,
which is extremely light, and is affixed to the half of a leaden
bullet; on account, therefore, of the disproportion between the weight
of the figure and that of its base, we may exclude the consideration of
the former, and confine our attention to the latter. The centre of
gravity of the hemispherical base is, of course, in its axis; and
therefore tends to approach the horizontal plane as much as possible,
and this can never be accomplished, until the axis becomes
perpendicular to the horizon. Whenever the curved surface is in any
other position, the centre of gravity is not in the lowest place to
which it can descend, as may be seen by the diagram which I have just
sketched. If the axis _a b_ be removed to _c d_, it is evident that the
centre of gravity will be raised, and that, if left alone, it would
immediately descend again into its original position.”
[Illustration: Fig. 14. Hemisphere shown in two positions using solid
and dotted lines.]
“I understand it perfectly,” said Tom. “When the axis _a b_ is
perpendicular, the centre of gravity will be in its lowest point, or as
near the earth as it can place itself; when, therefore, the figure is
pressed down, the centre of gravity is raised, and, consequently, on
the removal of that pressure, it will descend to its original position,
and thus raise the figure.”
[Illustration: Toy man with sword, turban, and shield, mounted on a
candlestick with weights jutting out and down from both sides.]
“I see you understand it. Here, then,” continued Mr. Seymour, “is
another toy in further illustration of our subject. It consists of a
small figure, supported on a stand by a ball, which is quite loose; and
yet it is made to turn and balance itself in all directions, always
recovering its erect position, when the force applied to it is removed.
The two weights, in this case, bring the centre of gravity considerably
_below_ the point of suspension or support, and therefore maintain the
figure upright, and make it resume its perpendicular position, after it
has been inclined to either side; for the centre of gravity cannot
place itself as low as possible, without making the figure stand erect.”
“That is very evident,” cried Louisa.
“I shall next exhibit to you,” continued Mr. Seymour, “a toy that
furnishes a very good solution of a popular paradox in mechanics; viz.
_A body having a tendency to fall by its own weight, how to prevent it
from falling, by adding to it a weight on the same side on which it
tends to fall._”
“That is indeed a paradox!” exclaimed Louisa. “The next time I see the
gardener sinking under the load of a heavy sack, I shall desire him to
lighten his burden by doubling its weight.”
[Illustration: Toy horse with its back legs on a ledge, with a weight
attached to its belly with a wire which curves back and down under the
ledge.]
“Will you, indeed, Miss Pert? I do not think so, after you have seen
the operation of the toy I am now about to exhibit. Here, you perceive,
is a horse, the centre of gravity of which would be somewhere about the
middle of its body; it is, therefore, very evident that, if I were to
place its hinder legs on the edge of the table, the line of _direction_
would fall considerably beyond the base, and the horse must be
precipitated to the ground; you will, however, perceive that there is a
stiff wire attached to a weight which is connected with the body of the
horse, and by means of such an addition, the horse prances with perfect
security at the edge of the precipice: so that the figure which was
incapable of supporting itself is actually prevented from falling, by
adding a weight to its unsupported end!”
The children admitted the truth of this statement, and were not
immediately prepared to explain it.
“The weight, indeed, appears to be added on that side; but, in reality,
it is on the opposite side,” said the vicar.
“In order to produce the desired effect,” observed Mr. Seymour, “the
wire must be bent, so as to throw the weight far back, under the table;
by which contrivance, since the centre of gravity of the whole compound
figure is thrown into the leaden weight, the hind legs of the horse
thus become the point of suspension, on which the ball may be made to
vibrate with perfect security.”
“Now I understand it,” cried Tom; “instead of the weight supporting the
horse, the horse supports the weight.”
“Exactly so. You perceive, therefore, from these few examples, that the
balancer, by availing himself of such deceptions, and combining with
them a considerable degree of manual dexterity, may perform feats,
which, at first sight, will appear in direct opposition to the laws of
gravity. There is also another expedient of which the balancer avails
himself, to increase the wonder of his performances, and that is the
influence of rotatory motion, which, you will presently see, may be
made to counteract the force of gravity.”
“I remember that the most surprising of all the tricks I witnessed was
one, in which a sword was suspended on a key, which turned round on the
end of a tobacco-pipe; on the top of the sword a pewter-plate was, at
the same time, made to revolve with great velocity.”
“I well remember the trick to which you allude. The rotatory motion
prevented the sword from falling, just as you will hereafter find the
spinning of the top will preserve it in an erect position. There is
also another effect produced by rotatory motion, with which it is
essential that you should become acquainted. You, no doubt, remember
that momentum, or the velocity of a body, will compensate for its want
of matter. A number of bodies, therefore, although incapable of
balancing each other when in a state of rest, may be made to do so, by
imparting to them different degrees of motion. I believe that you are
now acquainted with all the principles upon which the art of balancing
depends; and I have little doubt, should we again witness a performance
of this kind, that you will be able to explain the tricks which
formerly appeared to you so miraculous.”
[Illustration: Three boys using stilts.]
-----
Footnote 9:
In Scotland stilts are used to pass rivers.
Footnote 10:
A The vicar here alludes to the speech of Moloch (Paradise Lost, b.
ii. 1. 75):--
“That in our proper motion we ascend
Up to our native seat: descent and fall
To us is adverse.”
------------------------------------------------------------------------
[Illustration: A man holding a balloon with a face on it, blown up, and
six people laughing at the sight.]
CHAPTER V.
_The Chinese Tumblers, illustrating the joint effects of change in
the centre of gravity of a body, and of momentum.--Mr.
Twaddleton’s arrival after a series of adventures.--The Dancing
Balls.--The Pea-shooter.--A figure that dances on a
fountain.--The Flying Witch.--Elasticity.--Springs.--The game of
“Ricochet,” or Duck and Drake.--The Rebounding Ball.--Animals
that leap by means of an elastic apparatus.--A new species of
puffing, by which the Vicar is made to change countenance._
Early on Monday morning did the young group assemble in the library;
they had been told by Mrs. Seymour that their father had received a new
toy of a very interesting and instructive nature, and we can easily
imagine the eagerness with which they anticipated the sight of it.
“I trust,” said Mr. Seymour, “that after our late discussion, the
subject of the centre of gravity is thoroughly understood by you all. I
have also reason to think that the nature and effects of what is termed
_momentum_ have been rendered intelligible to you.”
“I certainly understand both those subjects,” answered Tom; and so
thought the rest of the party.
“Well, then, I will put your knowledge to the test,” observed Mr.
Seymour, “for you shall explain to me the mechanism of these _Chinese
Tumblers_.” Upon which he produced an oblong box, which, by opening,
formed a series of stairs or steps, and took from a drawer at its end
two grotesque figures (_Clown_ and _Pantaloon_), which were connected
with each other by two poles, which they appeared in the attitude of
carrying, pretty much in the way that the porters carry the poles of a
sedan-chair. The foremost figure was then placed upon the top step,
when, to the great astonishment of the whole party, the figures very
deliberately descended the several stairs, each turning over the other
in succession.
“There was a period in our history,” observed Mrs. Seymour, “when so
marvellous an exhibition would have subjected the inventor to the
penalties of sorcery.”
“That,” remarked Mr. Seymour, “may be said of most of the other
inventions which I have yet in store to illustrate the powers conferred
upon us by a knowledge of natural philosophy; but, as far as mechanical
skill is concerned, I doubt whether the ancients did not even surpass
us, especially in the art of constructing automata; and as quicksilver
was known in the remotest ages, I think it not improbable that it was
one of the agents employed by them on such occasions. If I remember
right, Aristotle describes a wooden Venus, which moved by means of
‘_liquid silver_;’ then, again, the moving tripods which Apollonius saw
in the Indian temples--the walking statues at Antium, and in the temple
of Hierapolis, and the wooden pigeon of Archytas,[11] ought,
undoubtedly, to be regarded as evidences of their mechanical resources.
But let us reserve these literary questions for the better judgment of
our worthy friend the vicar, and proceed to consider the mechanism of
the toy before us. Tom,” continued he, “take the figures in your hand
and examine them.”
No sooner had the young philosopher received the figures from the hand
of his father than he declared that the tubes were hollow, and that he
felt some liquid running backwards and forwards in them.
“You are quite right, my boy,” said Mr. Seymour, “they contain
quicksilver.”
“Now then I understand it,” cried Tom; “the quicksilver runs down the
tubes and alters the centre of gravity of the figures, and so makes
them tumble over each other.”
“Well, I acknowledge that is no bad guess as a beginning, and will
certainly explain the first movement; but you will be pleased to
recollect that the instant a new centre of gravity is thus produced the
figures must remain at rest--how, then, will you explain their
continued motion?”
“You said something, I think, about momentum; did you not, papa?”
“Certainly; and to its agency the continuance of the motions is to be
ascribed: but I will explain the operation more fully.”
Mr. Seymour then proceeded to point out the mechanism and movements of
the toy in a manner which we shall endeavour to convey to our readers
by the aid of the annexed engraving.
[Illustration: Two jokers connected by poles and strings and in the
process of descending some steps.]
“As soon as the figure A is placed upon the step D, in the position A
B, the quicksilver, by running down the inclined tubes, swings the
figure B round to C; and the centre of gravity having been thus
adjusted, the whole would remain at rest but for the contrivance to be
next described. Besides their connexion with the poles by means of
pivots, the figures are connected with each other by silken strings,
which keep the figure B steadily in its position, while it traverses
the arc until it arrives at C, when their increased tension has the
effect of capsizing it, and of thus producing a momentum, which, by
carrying its centre of gravity beyond the line of direction, causes it
to descend upon the step E, when the quicksilver, by again flowing to
the lowest part of the tubes, places the figures in the same position,
only one step lower, as they were at the commencement of their action;
and thus, by successive repetitions of the same changes, it is quite
evident that the figures must continue to descend as long as any steps
remain for their reception.”
“I understand it perfectly,” observed Louisa, with a smile of
satisfaction.
“I need scarcely say,” continued Mr. Seymour, “that there are some
niceties in the adjustment of the minuter parts of the apparatus,
without which the effect could not be accomplished; the quantity of
quicksilver, for instance, must bear its proper proportion to the
weight and dimensions of the figure: and in order to prevent its too
rapid passage along the inclined tubes, strings are stretched across
their interior to retard the stream. Then, again, some management is
necessary with regard to the silken strings, in order to ensure a
necessary degree of tension. I will now show you,” said he, “a single
tumbler, which will perform the same motions without the assistance of
any tubes.”
“But not without quicksilver,” observed Tom, “which, I suppose, must,
in this case, be put into the body of the figure.”
“You are quite right; and it is made to pass from one extremity of its
body to the other through a small orifice, which has the same effect as
the strings in the tubes, in breaking the current and preventing its
too rapid motion. In all other respects, the principle is the same as
in the double figures.”
Just as Mr. Seymour had terminated his exhibition of ‘_Le petit
Culbuteur_,’ the welcome appearance of the vicar infused fresh spirits
into the little party.
“My dear friends,” said Mr. Twaddleton, “I have been most provokingly
detained by that tiresome etymologist Jeffrey Prybabel. I made many
efforts to escape, but I was as a fly in a cobweb.”
“He is the greatest bore in all Christendom; I knew him well,” observed
Mr. Seymour, “when he practised as a Conveyancer in Gray’s-Inn, and
went by the nickname of the Riot Act; for, in such horror was he held,
that, if a number of persons were congregated, his approach was sure to
disperse them. But what has been the subject of your discourse?--was
the etymologist merely airing his vocabulary, or did he propose some
difficult question for discussion? Be this, however, as it may, I will
venture to say that he was, as usual, loquacious on the subject of
_mutes_--dry on the use of _liquids_, and descanting without end on the
importance of a _termination_?”
“Mr. Seymour, I am really and truly ashamed of you; punning, under any
circumstances, is a most disgraceful habit, but when employed to
distort the meaning of language it becomes absolutely criminal.”
To turn the subject of this discourse, the vicar proceeded to inform
Mr. Seymour that he had no sooner escaped from the fangs of Prybabel
than he encountered _Polyphemus_. Our readers may, perhaps, wonder who
this _Polyphemus_ could have been; we must, therefore, inform them that
Mr. Twaddleton, whose ideas were always tinctured with classical
colouring, had bestowed this appellation upon the renowned Dr. Doseall,
the Esculapius of Overton, because, as he said, his practice was like
the Cyclops, _strong but blind_; and Mr. Seymour declared that the
similitude was even more perfect than the vicar had contemplated, for
he observed that he certainly fattened upon the unhappy victims who
fell within his clutches.
With all our respect for the liberality of Mr. Seymour and the
kind-heartedness of the vicar, we must, in justice to this respectable
son of Apollo, express our disapprobation at so unprovoked a sarcasm.
We acknowledge that Dr. Doseall, by the aid of low bows and high
charges--of little ailments and large potions, had contrived to secure
a very comfortable balance on the creditor side of his worldly ledger.
We also admit, that after the example of other celebrated physicians,
he had one sovereign remedy, which he administered in every disease.
But what of that? he was often successful in his cures--that is to say,
his patients sometimes recovered _after_ they had taken his physic; and
is not that the test conventionally received in proof of the skill or
ignorance of greater physicians than Dr. Doseall? Nor can we persuade
ourselves into the belief, that a doctor who faithfully adheres to one
single remedy, is less likely to be right than those restless spirits
who are eternally coquetting with all the preparations of the
Pharmacopœia without ever remaining steady to any one of them. It has
been truly remarked, that the clock which stands still and points
steadfastly in one direction, is certain of being right twice in the
twenty-four hours, while others may keep going continually, and as
continually going wrong. Being ourselves no doctors, we merely throw
out this hint for the consideration of those who are learned in such
matters: but we beg pardon of our readers for this digression.
“Well,” said Mr. Seymour, “I am, at all events, rejoiced to see our
Trojan in safety, after such perilous adventures; and I hope that he is
now prepared to set sail again with us, on a new voyage of discovery. I
have been engaged,” continued he, “in explaining still farther the
nature of momentum, and I now propose to exhibit an experiment of a
different kind, in order to illustrate the same subject. You, no doubt,
remember,” continued Mr. Seymour, “that velocity makes up for weight:
although, therefore, a fluid, as air, or water, may, in a state of
quiescence, be unable to support a body, yet, by giving it a certain
velocity, it may acquire a sustaining power. I have here several gilded
pith-balls, through one of which I have run two pins, at right angles
to each other: the naked points, you perceive, are defended with
sealing-wax, to prevent any mischief that might arise from their
accidentally coming into contact with your face. By means of this brass
tube, (the stem of a tobacco-pipe will answer the same purpose,) I
shall produce a current of air by my breath, and you will observe that
the little ball will continue to dance, as if unsupported.”
Mr. Seymour then placed the pith-ball at the end of the pipe, and,
inserting its other extremity in his mouth, blew out the ball, which
immediately rose in the air, and continued to float about for several
seconds: he then drew in his breath, and caught it with much address on
one of its points; and in this manner, alternately floating and
catching it, did he continue to delight the wondering group for several
minutes.
Tom received the tube and ball from the hand of his father, and soon
succeeded in playing with it. Observe, gentle reader, the address with
which the boy manages it.
[Illustration: Tom keeping the pith-ball aloft by blowing into the
tube.]
“This reminds me of my pea-shooter,” said Tom, as he removed the tube
from his mouth, “with which I have often shot a pea across the
play-ground.”
“Exactly; and you will now understand the nature of the force by which
your pea was projected. The air blown from the lungs, gains such
momentum from the contracted channel in which it flows, as to impart
considerable velocity to the pea placed within the influence of its
current.”
Mrs. Seymour observed, that she had lately read in Waterton’s
“Wanderings in South America,” a very interesting account of the Indian
blow-pipe, which the natives of Guiana employ as an engine for
projecting their poisoned arrows, and which owes its power to the
principle of which Mr. Seymour had just spoken, and its unerring
accuracy to the skilful address of the Indian who uses it.(10)
“Mr. Seymour,” said the vicar, “I much like your experiment with the
pith-balls; but do tell me the use of the pins that are passed through
them.”
“They are not absolutely necessary for the success of the experiment:
indeed, I ought to have stated, that their only use is to ensure the
elevation of the ball to a certain distance above the orifice of the
tube, before it is set adrift.”
“‘_Ne turbata volent rapidis ludibria ventis_,’ as Virgil has it. I
duly appreciate the contrivance; but if the ball was set off at a
distance from the orifice, such an expedient would be unnecessary.”
“Certainly,” answered Mr. Seymour; “I will soon convince you that,
under the condition you propose, the pins are not essential.”
So saying, he placed the tube in his mouth, and by carefully holding
the ball at a distance of about half an inch from its orifice, he was
enabled to consign it at once to a continuous and steady stream of air,
which can never be commanded at the point from which the air issues;
and he thus succeeded in sustaining the ball in motion, in the same
manner as he did in the preceding experiment.
“We will now proceed to the orchard,” said Mr. Seymour, “where I have
prepared another pleasing exhibition of a similar description.”
The party accordingly left the Lodge, and when they had arrived at the
fountain, their father produced a small wooden figure, of which the
annexed is a sketch. Within its base was fixed a hollow sphere, or ball
of thin copper, which, when properly adjusted on a fountain, or _jet
d’eau_, was sustained by the momentum produced by the velocity of the
stream; so that the whole figure was balanced, and made to dance on the
fountain, as the pith-ball had been made to play in the current of air.
[Illustration: Man sitting at the top of a fountain’s stream of water.]
The children were much gratified at witnessing so curious an
exhibition. Mr. Twaddleton laughed heartily at the ludicrous effect it
produced, and observed that, although he had never before seen the
experiment, he had frequently heard of it; and he added, that he
understood it to be a very common toy in Germany and Holland.
“I have for some time,” said Mrs. Seymour, “been trying to construct a
light figure of this kind, which shall dance on a current of air; and I
believe I have at length succeeded. The head I have formed of the seed
vessel of the _Antirrhinum_, which has a striking resemblance to a
face, and possesses, moreover, the indispensable condition of
lightness. The dress is made of silver paper, stretched over a cone of
the same material. From its appearance I have named it the _Flying
Witch_.”
“I admire your ingenuity,” said Mr. Seymour, “and I have no reason to
doubt the success of your enterprise.”
“I found it convenient,” continued Mrs. Seymour, “to place a stage of
card below the orifice of the tube, in order to steady the figure as
she rises, and to receive her as she falls.”
“Your principal care,” observed her husband, “must be to throw the
centre of gravity of the figure as low as possible.”
On the party returning to the library, Mr. Seymour expressed a wish
that, before they suspended their morning’s recreations, they should
take into consideration a peculiar property of matter, which they had
not yet discussed.
“And what may that be?” asked Louisa.
“ELASTICITY,” replied her father; “and I wish to hear whether Tom can
explain to us the meaning of the term.”
Tom very well knew what was meant by Elasticity; but he was like many a
merchant with a bill of exchange, who, although well acquainted with
its value, has not sufficient small change to cash it. Tom wanted words
to enable him to furnish a clear definition; his father, therefore,
kindly relieved his embarrassment, by informing him that “it was a
property inherent in certain bodies, by which they possessed a
disposition to have their form altered by force or pressure, and to
recover it on the removal of that pressure, throwing off the striking
body with some degree of force: for example,” continued he, “the cane
which I hold in my hand can be bent to a certain extent, and then, if I
let it go, it will immediately return to its former condition with
considerable force.”
Louisa inquired whether bending and pressing upon a body were the same
thing. Mr. Seymour replied, that the form of an elastic body might be
altered either by compression or distension, and that _bending_ was, in
fact, only a combination of these two methods; “For,” said he, “when a
straight body, like my cane, is bent, those particles of it which are
on the one side are compressed, while those on the other are distended.
But let us proceed with the subject. I have said that elastic bodies,
on returning to their original form, throw off the striking body with
some degree of force. I have here,” continued Mr. Seymour, taking out
of his pocket a wooden image of a cat, “a toy which I intend as a gift
to John; it will serve to illustrate our subject. The tail, you
perceive is movable, one of its ends being tied to a piece of catgut,
which is a highly elastic substance. When I bend the tail under the
body of the animal, I necessarily twist the string; and by pressing the
other end of the wooden tail upon a piece of wax, I can retain it for a
few seconds in that situation.”
Mr. Seymour having fixed the tail in the manner above described, placed
the wooden image on the ground, when, in a few seconds, it suddenly
sprang forward, to the great delight of the younger children.
“Can you explain this action?” asked Mr. Seymour.
“The wax,” answered Tom, “was incapable of holding the end of the tail
longer than a few seconds; and as soon as it was let loose, the
elasticity of the catgut enabled it to return to its former condition;
in doing which the tail struck with force against the ground, which
threw off the body of the cat and produced the leap.”
“Very well explained; and you, no doubt, will readily perceive that the
operation of steel springs depends upon the same principle of
elasticity: a piece of wire or steel, coiled up, may be made to set a
machine in motion by the endeavour it makes to unbend itself. This is
the principle of the spring in a watch. When our watches are what is
termed _down_, this steel has uncoiled itself; and the operation of
winding them up, is nothing more than that of bending it again for
action.(11) If the elasticity of a body be _perfect_,” added Mr.
Seymour, “it will restore itself with a force equal to that with which
it was compressed. As I have given John a toy, it is but fair that I
should reward you, Tom: open that box, and examine the gift which it
contains.”
Tom received the present from his father, and proceeded to open the
lid, when, to his great astonishment, the figure of an old witch
suddenly sprang upwards. Mr. Seymour explained its mechanism, by
stating “that the figure contained a wire coiled up like a corkscrew,
and which, upon the removal of the pressure of the lid which confined
it, immediately regained its original form.”(12)
Tom inquired what kind of bodies was most elastic. He was informed that
the air was the most elastic of all known substances, and had, for that
reason, been distinguished by the name of an _elastic_ fluid. Hard
bodies were so in the next degree; while soft substances which easily
retain impressions, such as clay, wax, &c. might be considered as
possessing but little elasticity.
“I should have thought,” said Louisa, “that neither clay nor wax had
possessed _any_ elasticity.”
“My love, we know not any bodies that are absolutely, or perfectly,
either hard, soft, or elastic; since all partake of these properties,
more or less, in some intermediate degree. Liquids are certainly the
least elastic of all bodies; and, until lately, water was regarded as
being perfectly inelastic;[12] but recent experiments have shown it
capable of compression, and of restoring itself to its original bulk,
as soon as the pressure is removed; it must, therefore, possess some
elasticity. Indeed,” said Mr. Seymour, “we might have anticipated such
a result from the effects which present themselves in the well-known
game of ‘_Ricochet_,’ or _Duck and Drake_.”
“_Duck and Drake!_” exclaimed Louisa; “for goodness’ sake, what can
that game be?”
“I dare say your brother will not have any difficulty in explaining it
to you.”
Tom informed her that it was a game in which any number of boys threw a
stone, or a flat piece of tile, into the water; and that he whose stone
rebounded the greatest number of times was the conqueror.
“It is a very ancient game,” said Mr. Seymour, “and had the vicar been
present, we should have heard a learned disquisition upon it; as he,
however, is unfortunately absent, I must tell you all I know upon the
subject. It was called by the Greeks _Epostrakismos_,[13] and was
anciently played with flat shells. Now it is evident that the water
must possess some degree of elasticity, or the stone could not
rebound(13); but I shall have occasion to revert to the subject
hereafter.”
“And are my marbles elastic?” asked Tom.
“Undoubtedly; but not to the same extent as your ball. There,” said Mr.
Seymour, throwing his ball against the wall, “see how it rebounds.”
“The return of the ball,” observed Tom, “was, I suppose, owing to its
elasticity; and I now understand why one filled with air rebounds so
much better than one stuffed with bran or wool.”
“You are quite right; and the return of the ball, after having struck
the wall, affords an example of what is termed _reflected_ motion, upon
which I shall have to remark when we come to the interesting subject of
‘Compound Forces;’ but at present, my only wish is to render the
property of elasticity intelligible to you. It is a force of very
extensive application; there is scarcely a machine wherein the
elasticity of one or more solids is not essentially concerned. Nature,
also, avails herself of this property to accomplish many of her
purposes. Fleas and locusts are enabled to jump two hundred times the
height of their own bodies by means of a springy membrane, easily
visible by a microscope; so that, supposing the same relative force to
be infused into the body of a man six feet high, he would be enabled to
leap three times the height of St. Paul’s: and the regular dispersion
and sowing of the seeds of several plants is effected by a spring,
which is wound sometimes round the outside, and at others, round the
inside, of the case in which the seeds are contained.”(14)
“I suppose,” said Tom, “that it is by some such spring shrimps are
enabled to leap to the tops of cataracts, as I have read in my work on
Natural History.”
“Many species of fish are thus enabled to leap, by bending their bodies
strongly, and then suddenly unbending them with an elastic spring; and
the long-tailed crayfish, and the common shrimp, leap by extending
their tails, after they have been bent under their bodies:--but the
most striking example of this kind is the leap of the salmon; just
under the cataract, and against the stream, he will rush for some
yards, and rise out of the spray six or eight feet; and, amidst the
noise of the water, he may be heard striking against the rock with a
sound like the clapping of hands; if he find a temporary lodgment on
the shelving rock, he will lie quivering and preparing for another
summerset, until he reaches the top of the cataract; thus at once
exhibiting the elasticity of his bones and the power of his muscles.”
“We will now conclude our diversions,” said Mr. Seymour, “with an
exhibition of a very striking description. Here,” cried he, as he
removed a small piece of apparatus from a box which stood on the table,
“is a toy, at which the sternest philosopher, nay, even Heraclitus, of
weeping memory, could not refrain from laughing.”
He then displayed a small ball of Indian rubber, on which was painted
an exact resemblance of the worthy vicar, executed under the direction
of Mr. Seymour, by that inimitable artist, George Cruikshank. The ball
was connected with an air syringe, by which it was easily distended. It
gradually increased in magnitude, swelling, like the gourd of Jonah, as
the inflation proceeded, and the countenance of the vicar progressively
enlarged to the size of the full moon, without the least alteration in
the character or expression of its features.
“I declare,” said Mr. Seymour, “the vicar _improves upon acquaintance_.”
“It must be acknowledged that you have _puffed_ him into consequence,”
observed Mrs. Seymour.
The countenance had, after a short time, swelled to ten times its
original dimensions: the children deafened Mr. Seymour with their
shouts, and the good-humoured clergyman was actually convulsed with
laughter. The stop-cock was now turned; the elastic bladder became
smaller and smaller, and the features underwent a corresponding
diminution, until they once again assumed their original dimensions.
“You perceive, my dear Sir, that I make you _look small_ again.”
“That is by no means an unusual effect of your jokes,” replied the
vicar.
“Now, Tom,” said his father, “it is for you to explain the nature of
the exhibition you have just witnessed.”
Tom proceeded accordingly.
“The bladder was highly elastic, and therefore readily yielded to the
pressure of the air, and became distended. As soon, however, as the
pressure was removed, the air was driven out again with force, and the
particles of the Indian rubber returned to their former condition. But
I observed one circumstance which I do not understand,” said Tom: “when
you first turned the stop-cock, the air rushed out with great violence,
and the ball diminished very rapidly; but it gradually slackened,
until, at last, the bladder could scarcely be seen to contract.”
“I rejoice to find that you were so observant,” said his father: “the
effect you noticed depended upon a general law of elasticity. Elastic
bodies, in the recovery of their forms from a state of compression,
after the removal of the compressing force, exert a greater power at
first than at last, so that the whole progress of restoration is a
_retarded_ motion.”
The vicar, who had listened with profound attention to the explanation
which the boy had offered, rushed forward at its conclusion, and
clasping him in his arms, declared, that a first-class man of Trinity
could not have succeeded better.
“But let us now, if you please, Mr. Seymour, suspend our researches:
recollect,” said the vicar, “that your birds are, as yet, scarcely
fledged; and they will, therefore, make greater advances by short
flights frequently repeated, than by uninterrupted progression.”
We heartily concur in this opinion, and shall, therefore, terminate the
chapter.
-----
Footnote 11:
Upon this subject, Dr. Brewster’s Introductory Letter on Natural
Magic will be read with interest and advantage.
Footnote 12:
The comparative inelasticity of water will be shown hereafter.
Footnote 13:
Pollux, lib. ix. c. 7.
------------------------------------------------------------------------
CHAPTER VI.
_The arrival of Major Snapwell, and the bustle it occasioned.--The
Vicar’s interview with the stranger.--A curious discussion.--A
word or two addressed to Fox-hunters.--Verbal corruptions.--Some
geometrical definitions.--An enigma._
As the ladies of Overton were regaling themselves with a sociable dish
of tea and chat, the conversation was abruptly interrupted by the
appearance of a chariot-and-four, that passed along the road with
luxurious speed, and which, as Miss Kitty Ryland declared, announced,
by the dignified suavity of its roll, that the personage it conveyed
must be of superior rank.
“Those,” exclaimed she, “who cannot at once distinguish such
‘spirit-stirring’ sounds from the discordant rattle of a plebeian
chaise, deserve to wear the ears of Midas.”
This extraordinary subtlety of Miss Ryland’s ears is said to have been
conferred upon them by those universal promoters of bodily vigour,
_air_ and _exercise_, of which they had received the combined advantage
by the ingenious habit of listening to whispers through a certain
pneumatic apparatus, familiarly termed a _key-hole_. In farther proof
of the fidelity and alertness of her auditory establishment, we may
just state, that, on passing Doseall’s shop, she never failed to
distinguish, by the sound of the mortar, whether the medicines under
preparation were designed for the stomachs of the rich or the poor. The
vicar even admitted the correctness of her discrimination, for he had
himself observed that the pestle beat _dactyls_ in one case, and
_spondees_ in the other.
While the carriage was passing the window, the maiden companions were
breathless with wonder, each catching a glance from the countenance of
her neighbour, which heightened, as it were, by reflection, the
surprise depicted on her own.
“Overton,” exclaimed Miss Noodleton, “is doubtless by this time
honoured by the arrival of some distinguished stranger; but who he is,
or what may be the object of his visit, I am at a loss to divine.”
“Pooh!” cried Miss Puttle; “what a fuss is here about a green carriage
and four hack horses! I doubt not but that it has conveyed some visitor
to the vicar: had the Seymours expected any company, I must have heard
of it yesterday.”
“To the vicar!” exclaimed Miss Phillis Tapps; “and pray, Miss Puttle,
allow me to ask whether you ever heard of the peacock nestling with the
crow?”
“Or of the eagle taking up its abode in an ivy-bush?” vociferated Miss
Ryland.
Conjectures were vain, and the party determined to resolve itself into
a committee of inquiry. In the first place, it was judged expedient to
see and question Ralph Spindle, whom Dr. Doseall employed on the
arrival of a stranger, as certain insects are said to use their
‘_feelers_’ to discover the approach of any prey that may serve them as
food.
The stranger was soon discovered to be a Major Snapwell, a rich and
eccentric old bachelor, who had served in various campaigns in
different parts of the globe, and received a competent number of
wounds, in the defence of his king and country. His income was reported
to be large, and it was said, that he had not any near relative to
enjoy the reversion, since his nephew had perished about two years
before by shipwreck. The circumstances that led to this disastrous
event were believed to have so affected the veteran, as to have
occasioned a very serious illness, and a consequent state of
despondency, for which his physicians advised a constant change of
scene; so that he had been rambling about the Continent during the last
year and a half, accompanied only by his faithful servant, Jacob
Watson, who was as much attached to the Major, as was ever a
Newfoundland dog to his master.
Such was the information derived from Annette, the vicar’s housekeeper:
what proportion of fiction was mingled with its truth, the reader will
probably soon be able to discover.
“Well, Jacob,” said the Major, as his trusty but asthmatic valet was
leisurely buttoning on the long gaiters of his master the morning after
his arrival, “what do you hear about this village of Overton? Are there
any sociable neighbours? I like the country; it is beautiful, Jacob,
and the air appears mild: it promises to be the very place to kindle
the sparks of my expiring constitution; and should you, at the same
time, get your broken-winded bellows mended, my vital flame might,
perhaps, burn a little brighter. But tell me, what do you hear of it,
Jacob?”
“Why, and please you, Major, I just now met an old crony of mine, Mrs.
Annette Brown, at the Devil and the Bag of Nails----”
“And pray, Jacob,” exclaimed the Major, “who taught you to speak thus
irreverently of the village blacksmith?”
“The village blacksmith! Lord love you, it is the sign of the village
alehouse!”
“Then it is a very odd one; but go on with your story.”
“As I was saying, Major, I met an old acquaintance who is housekeeper
to Mr. Twaddleton, a bachelor gentleman, and the vicar of the parish.
She tells me her master is downright adored in the place: though he
must needs be a queer mortal, for she says he is so fond of _antics_
that he won’t suffer a mop or broom in his house, lest, I suppose, it
should spoil the hopping of the fleas, and put an end to the fly’s
rope-dance upon a cobweb.”
“Jacob, Jacob, you are a wag, and had better go and offer your
services to this merry parson; although, I fear, your asthmatic pipes
would prove but a sorry accompaniment to his capering. But
pshaw!--fiddlestick!--stuff and nonsense!--who ever heard of a vicar
being fond of antics!--you are imposed upon, Jacob.”
“I am sure that how Annette told me as much. Ay, and she said he had
all sorts of _curiosities_ in his parlour--such as grinning faces, dogs
with three heads, rusty swords, and I do not know what besides.”
“I see it!--see it all plainly!” exclaimed the Major; “and your story
has so delighted me that I could almost dance myself.” This respectable
clergyman, thought he, is, doubtless, an antiquary, a virtuoso--what a
delightful companion will he prove! And a bachelor like myself!--what
_tête-à-têtes_ do I anticipate!
“Jacob,” exclaimed the Major, “you should have said that the vicar was
fond of, or, to speak more correctly, devoted to _antiques_, not to
_antics_. But, tell me whether there are any other agreeable persons in
this village?”
“There’s the squire and his family,” answered the valet.
“The name, the name, Jacob?”
“Squire Seymour, and please you, Major.”
“Seymour, Seymour!” repeated the Major; “I seem to know that name--let
me remember.”
The Major’s cogitations, however, were abruptly cut short by the
entrance of the servant-maid, who informed him that Mr. Vicar
Twaddleton had called.
“I beg that Mr. Twaddleton may be admitted.--Jacob, place a chair.”
“Mr. Twaddleton,” said the Major, as he advanced towards the door to
meet his visitor, “I feel obliged and honoured by your kind attention.
As a perfect stranger, I could scarcely have expected this civility;
but your village, surrounded as it is by all the softer charms of
Nature, is calculated to impress the hearts of its inhabitants with a
kindred amenity. The inhabitants are, doubtless, much attached to their
country.”
“Proverbially so: never was Ulysses more attached to his Ithaca! Allow
me, also, to say that we all rejoice at the arrival of visitors; and,
as vicar of the parish of Overton, I should consider myself criminally
deficient in my duty were I to suffer a respectable stranger to depart
from us without his having received the mark of my respect, and the
tender of my humble but cordial hospitality. I am an old-fashioned
person, Major Snapwell, and am well aware that these antiquated notions
do not altogether accord with the cold and studied forms of the present
day.”
“Mr. Twaddleton,” exclaimed the delighted Major, “I thank thee, most
heartily thank thee, in the name of all those whose hearts have not yet
been benumbed by worldly indifference. Sit thee down--I abhor
ceremony--and let me beg of you not to take offence at a question to
which I am most anxious you should give me an answer. Are you, my dear
Sir, as I have just reasons for supposing, an ANTIQUARY?”
“I am undoubtedly attached to pursuits which might have favoured such a
report.”
“I thought so; I guessed as much. Then give me your hand; we must be
friends and associates. If there be a pursuit on earth to which I am
devotedly attached, it is to that of antiquities; and, let me add,”
continued the Major with increasing animation, for, like bottled beer,
he was the brisker for warmth, “that if there be a literary character
to whom the professor of arms ought to feel superior gratitude, it is
to the antiquary. How many victories, what valiant deeds, must have
perished in the memory of mankind but for the kind offices of the
virtuoso! under whose vivifying touch the laurels of the victor have
bloomed with renovated vigour! and when the scythe of Time has left
them to wither, and to be scattered on the wings of the wind, he
collects their remains, and piously deposits them in a splendid
mausoleum, in order to preserve them to the latest posterity!”
It were difficult to say, whether astonishment at the Major’s warmth,
delight at the congenial sentiments he had expressed, or admiration at
the language in which they had been conveyed, was the feeling
predominant in the vicar’s mind, nor do we deem it necessary to
inquire; suffice it to say, that, from the conversation of a few
minutes, these two gentlemen felt incited to a mutual regard by
sympathy and congeniality of soul; so true is it that, while we may be
strangers with the companions of years, we may become friends with the
strangers of yesterday!
“Major Snapwell,” said the vicar, “I may truly mark this day in the
diary of my life in red letters; your society will add to my happiness,
by extending the sphere of my literary intercourse. When may I expect
the pleasure of your company at the vicarage? I am really impatient to
show you my coins and a few dainty morsels of _virtù_.”
“I shall be at your service to-morrow,” answered the Major; “but I must
now say something about my plans, for it is possible that you may
assist me in carrying them into execution.”
“Command me,” said the vicar.
“For my present purpose, it is only necessary to state, that I have a
nephew whom I have adopted as my son; I superintended his education; he
arrived at manhood, and became an accomplished scholar and a polished
gentleman. Naturally anxious to visit the ancient mistress of the
world, he readily obtained my approbation of his plan. He embarked at
Marseilles; but, meeting with one of those treacherous gales so
characteristic of the Mediterranean, he was shipwrecked in the bay of
Genoa. For three years did I mourn him as dead, and it was only by a
train of circumstances of the most extraordinary description that I at
length discovered him to be living. I will not now trouble you with the
details of this most singular history; suffice it to say he is now
well, and about to be married to a young lady for whom he has long
entertained the purest attachment. I am in search of a country
residence for them, and hearing that a Sir Thomas Sotherby, a resident,
I understand, in your neighbourhood, is most desirous of disposing of
Osterley Park, and offers many advantages to any one who will take it
off his hands, and as I have both the inclination and the means to
become its possessor, I have travelled hither for the purpose of
inspecting it. So now you have my history.”
“It is perfectly true,” said the vicar, “that Sir Thomas is willing to
make a considerable sacrifice in order to obtain an immediate
purchaser. The health of her Ladyship is in so precarious a state that
her physicians have ordered her to proceed, without delay, to Madeira.
Sir Thomas, Major, is a fox-hunter, and I will venture to say that no
one will miss him but the doctor and the foxes--the one will lose a
profitable friend, the other a relentless enemy--‘_Gaudet equis et
canibus_,’ as the poet has it.”
“Indeed! but I am no fox-hunter, and I therefore fear that, in the
opinion of the country, Osterley Park will not exchange its proprietor
to advantage. Pray, vicar, may I ask whether you are addicted to
field-sports?”
“Addicted to field-sports!” repeated the reverend antiquary: “I am
surprised, mortified, absolutely shocked! I--I addicted to
field-sports!”
“Nay, Mr. Twaddleton,” observed the Major, “I am really sorry that I
should have unintentionally excited your indignation. I am not aware
that there is anything in the innocent pastime to which I have alluded
inconsistent with your station and acquirements. As an antiquary, I
need hardly remind you that the fathers of the Church were amongst the
keenest sportsmen. Do you not remember the amusing portrait which
Chaucer has given us of a sporting monastic in the 14th century, and
which, by the by, was the model from which Sir Walter Scott drew the
character of his Abbot in ‘Ivanhoe?’ Then again, need I call to your
recollection the fame of Walter, Archdeacon of Canterbury, who was
promoted to the see of Rochester in 1147, and who is said not only to
have spent the whole of his time in hunting, but to have been as keen a
sportsman at eighty as he was at twenty years of age? Then again, there
was Reginald Brian, translated to the see of Worcester in 1352; and
William de Clowne, whom his biographer celebrated as the most amiable
ecclesiastic that ever filled the abbot’s throne of St. Mary in
Leicestershire, the most knowing sportsman after a hare in the kingdom;
insomuch, indeed, that Richard II. and his son allowed him annual
pensions for his instructions in the art?”
“Major Snapwell, antiquity can no more privilege error, than novelty
can prejudice truth,” exclaimed the vicar: “but, to be serious,”
continued he, “I never could discover the principle upon which the
pleasure of this said diversion of Diana can depend; and yet I do
assure you, sir, that I have not failed to submit the question to a
logical examination. Thus, for instance:--the fox emits from his body
certain odorous particles;--that is my _major_, and I say _concedo_:
very well; I proceed. The structure of the olfactory organs of the
canine species enables them to perceive this said odour: that is my
_minor_, and I say again _concedo_. But I should much like to be
informed how any logician can defend the consequence which is deduced
from these premises. To speak more syllogistically, why am I pleased to
put my neck in jeopardy, _because_ my dogs happen to perceive a smell?”
The Major laughed heartily at the very ludicrous point of view in which
the worthy vicar had thought proper to represent the subject. Their
discourse now took a different turn. The Major inquired what might be
the origin of the singular sign of the village inn--_The Devil and the
Bag of Nails?_ “Satan,” continued the Major, “is unquestionably the
patron of the public-house; but why he should be represented as holding
in his hand a bag of nails, I cannot divine, unless, indeed, in
reference to the old adage, that ‘_Every glass of spirit is a nail in
your coffin._’”
“Ha! ha! ha! whimsical enough,” cried the vicar; “but, unfortunately,
your explanation is not the true one. The sign,” observed Mr.
Twaddleton, “is not quite so uncommon as you seem to suppose; it was
originally ‘_Pan and his Bacchanals_,’ but, by a very natural
transition, the figure of the sylvan deity, which is certainly
terrific[14] enough to sanction the mistake, has passed into that of
the evil tempter; while the word _Bacchanals_, by one of those verbal
corruptions so common in all languages, has been converted into the
_bag of nails_.”
“Very true,” said the Major; “whenever the vulgar are incapable of
understanding the meaning of a word, they are sure to substitute for it
some one which has the nearest resemblance to it in sound, and which is
more familiar to them. I had but just now an excellent instance of this
kind: my blundering servant Jacob insisted upon it that you were fond
of _antics_; and before I left London, on sending him out to purchase a
_Court Calendar_, what do you suppose he brought home?--a _Quart
Colander_!”
The vicar was much amused by the absurdity of the mistake.
“I lately heard,” continued the Major, “of a Welsh squire, who, upon
being questioned whether _Socinianism_ or _Arianism_ prevailed in his
district, replied, that he could not answer that question, but that he
knew there had been a great deal of _Rheumatism_.”
But the good company of the Major and his newly acquired friend must
not detain us any longer from our duty. Mr. Seymour and his young
family have reassembled in the library, and it is necessary that we
should immediately join them. Some of our readers may, perhaps, decline
accompanying us upon this occasion; for the subject to be discussed,
however necessary it may be, is certainly not so entertaining as many
of those which have engaged our attention. If this be the case, they
may make a short cut, and join us again at the beginning of the
following chapter. The children had arranged themselves around the
table, when their father observed, that it would be necessary for their
future progress, to devote an hour or two to the consideration of
several mathematical figures and terms.
“As to mathematical figures,” said Tom, “if you allude to squares,
circles, and figures of that description, and to parallel lines,
angles, and so on, I can assure you that I am already well acquainted
with them; for the work you have given us on PAPYRO-PLASTICS[15] has
fully instructed me in those particulars.”
“If that be the case,” replied Mr. Seymour, “you will not have any
difficulty in answering my questions; but we must, nevertheless, go
regularly through the subject, for the sake of your sisters, who may
not be equally proficient in this elementary part of geometry: tell me,
therefore, in the first place, what is meant by a _parallelogram_.”
“A four-sided figure,” answered Tom.
“That is true; but are there not some other conditions annexed to it?”
“Yes; its opposite sides are parallel.”
“And what do you understand by the term _parallel_?”
“Lines are said to be parallel,” said Tom, “when they are always at the
same distance from each other, and which, therefore, can never meet,
though ever so far continued.”
“You are quite right. What is a _square_?”
“A four-sided figure, in which the sides are all equal, and its angles
all right angles.”
“Good again: but let me see whether you have a correct notion of the
nature of an angle.”
“An angle is the opening formed by two lines meeting in a point.”
Mr. Seymour here acknowledged himself perfectly satisfied with his
son’s answers, and said, that he should accordingly direct his
attention more particularly to Louisa and Fanny; and, taking his
pencil, he sketched the annexed figure.
[Illustration: Fig. 1. Circle with two lines running through it.]
“You perceive, Louisa,” said her father, “that the line A C makes two
angles with the line B D, viz. the angle A C D and the angle A C B; and
you perceive that these two angles are equal to each other.”
“How can they be equal?” cried Fanny, “for the lines are of very
different lengths.”
“An angle, my dear girl, is not measured by the _length_ of the lines,
but by their _opening_.”
“But surely,” said Louisa, “that amounts to the same thing: for the
longer the lines are, the greater must be the opening between them.”
“Take the pair of compasses,” replied her father, “and describe a
circle around these angles, making the angular point C its centre.”
“To what extent am I to open them?”
“That is quite immaterial; you may draw your circle of any magnitude
you please, provided it cuts both the lines of the angles we are about
to measure. All circles, of whatever dimensions, are supposed to be
divided into 360 parts, called _degrees_; the size, but not the number,
of such degrees will therefore increase with the magnitude of the
circle. And since the opening of an angle is necessarily a portion of a
circle, it must embrace a certain number of degrees; and two angles
are, accordingly, said to be equal, when they contain an equal number
of them.”
“Now I understand it,” said Louisa: “as the dimensions of an angle
depend upon the number of degrees contained between its lines, it
evidently must be the _opening_, and not the _length_ of the lines,
that determines the measure of the angle.”
“Say, rather, the _value_ of the angle, for that is the usual
expression: but I perceive you understand me; tell me, therefore, how
many degrees are contained in each of the two angles formed by one line
falling perpendicularly on another, as in the above figure.”
“I perceive that the two angles together are just equal to half the
circle; and, since you say that the whole circle is divided into 360
degrees, each angle must measure 90 of them, or the two together make
up 180.”
“You are quite right, and I beg you to remember, that an angle of 90
degrees, is called a _right_ angle, and that, when one line is
perpendicular to another, it will always form, as you have just seen, a
right angle on either side.”
“I now understand,” said Louisa, “what is meant BY lines being at
_right angles to each other_: But, papa,” continued she, “what are
_obtuse_ and _acute_ angles, of which I have so often heard you speak?”
[Illustration: Fig. 2. An acute (A) and an obtuse (B) angle.]
Mr. Seymour replied, that he could better explain their nature by a
drawing, than by any verbal description. “Here,” said he, “is an acute
angle, A; and here an obtuse one, B: the former, you perceive, is one
that contains less than 90 degrees; the latter, one which contains
more, and is consequently greater than a right angle.”
Louisa fully comprehended the explanation, and observed, that she
should remember, whenever an angle measured less than a _right_ angle,
that it was _acute_, and when more, _obtuse_. “But you have not yet
explained to me,” she continued, “the meaning of a _triangle_.”
“That is a term denoting a figure of three sides, and angles. I dare
say Tom can describe the several kinds of triangles.”
Tom accordingly took the pencil, and drew a set of figures, of which
the annexed are faithful copies.
[Illustration: Fig. 3. Three triangles, labeled A, B, and C.]
“A,” said he, “is an _Equi-lateral_ triangle; its three sides being all
equal. B is a _Right-angled_ triangle, having one right angle. C
represents an _Obtuse-angled_ triangle, it having one obtuse angle. An
_Acute-angled_ triangle is one in which all the three angles are acute,
as represented in figure A.”
“As you have succeeded so well in your explanation of a triangle, let
us see whether you can describe the nature of a circle.”
“It is a round line, every part of which is equally distant from the
centre.”
“And which round line,” said Mr. Seymour, “is frequently called the
_circumference_. What is the diameter?”
“A straight line drawn through the centre, and terminating in the
circumference on both sides.”
“And an arc?” said Mr. Seymour.
“Any portion of the circumference.”
“Now let me ask you, what name is given to a line which joins any two
opposite angles of a four-sided figure?”
“The _diagonal_, papa.”
“You are quite right,” said Mr. Seymour; and, turning towards the
girls, he desired them to remember that term, as they would frequently
hear it mentioned during their investigation into the nature of
“Compound Forces.” “I really think,” continued their father, “that Tom
is as capable of instructing you in these elementary principles as
myself; I shall, therefore, desire you, my dear boy, to conclude this
lecture during my absence; remember, that by teaching others we always
instruct ourselves: but before I quit you, I will give you a riddle to
solve, for I well know that you all delight in an enigma.”
“Indeed do we,” said Louisa.
“Pray let us hear it, papa,” cried Fanny.
Mr. Seymour then recited the following lines, which he had hastily
composed; the point having, no doubt, been suggested on the instant, by
the remark he had just offered.
“Here’s a riddle for those who delight in their gold,
Which they p’rhaps may explain, when my story is told;
No treasure’s so precious, and yet those who gain me,
Though they give me away, will always retain me!
Indeed, if they wish to increase their rich store,
By giving away, they will only add more!!
To Fancy’s quick eye, in what forms have I risen,
And Poets declare that my birth was in heaven;
To some as a flame, as a stream, or a fountain,
To others I seem as a tower or mountain.
Should these hints not betray me, I only can say,
You do not possess me--I hope that you may.”
“Why,” cried Tom, “what can that be, of which the more we give away,
the more we have left?”
“Ay,” added Louisa, “and that we actually _increase_ the store, by
_giving away_ a part of it!”
“It is some word, I think,” observed Fanny; “do you not remember that
mamma asked us what that was, from which we might take away _some_, and
yet that the _whole_ would remain?”
“To be sure,” cried Tom, “I remember it well; it was the word
_wholesome_.”
Mr. Seymour here assured them, that the enigma they had just heard, did
not depend upon any verbal quibble; and that as the object of its
introduction was to instruct, rather than to puzzle them, he would
explain it, and leave them to extract its moral, and profit by its
application.
“It is KNOWLEDGE,” said he.
“‘_No treasure’s so precious_,’” repeated Louisa; “certainly
none;--‘_and yet those who gain me, though they give me away, will
always retain me_;’--to be sure,” added she. “How could I have been so
simple as not to have guessed it? We can certainly impart all the
knowledge we possess, and yet not lose any of it ourselves.”
“By instructing others,” said Mr. Seymour, “we are certain, at the same
time, of instructing ourselves, and thus to increase our store of
knowledge. Let this truth be impressed upon your memory, and, after our
conversations, examine each other as to the knowledge you have gained
by them: you will thus not only fix the facts more strongly in your
recollection, but you will acquire a facility of conversing in
philosophical language.”
-----
Footnote 14:
To the terror-inspiring power of Pan we owe the word “_Panic_.”
Footnote 15:
“PAPYRO-PLASTICS,” or the Art of Modelling in Paper; from the German,
by Boileau, _London_, 1825. The Author strongly recommends this
interesting little work, as opening a new source of instructive
amusement. His own children have derived from it many hours of
rational recreation.
------------------------------------------------------------------------
CHAPTER VII.
_Compound Forces.--The Composition and Resolution of
Motion.--Rotatory Motion.--The Revolving Watch-glass.--The
Sling.--The Centrifugal and Centripetal Forces.--Theory of
Projectiles.--A Geological conversation between Mr. Seymour and
the Vicar._
On the following morning, Mr. Seymour proceeded to explain the nature
of “COMPOUND FORCES.” The young party having assembled as usual, their
father commenced his lecture by reminding his auditors, that the motion
of a body actuated by a single force was always in a right line, and in
the direction in which it received the impulse.
“Do you mean to say, papa, that a single force can never make a body
move round, or in a crooked direction; if so, how is it that my ball,
or marble, will frequently run along the ground in a curved direction?
Indeed, I always find it very difficult to make it go straight.”
“Depend upon it, my dear, whenever the direction of a moving body
deviates from a straight line, it has been influenced by some second
force.”
“Then I suppose that, whenever my marble runs in a curved line, there
must be some second force to make it do so.”
“Undoubtedly; the inequality of the ground may give it a new direction;
which, when combined with the original force which it received from
your hand, will fully explain the irregularity of its course. It is to
the consideration of such compound motion that I am now desirous of
directing your attention: the subject is termed the “COMPOSITION OF
FORCES.” Here is a block of wood, with two strings, as you may
perceive, affixed to it: do you take hold of one of these strings,
Louisa; and you, Tom, of the other. That is right. Now place the block
at one of the corners or _angles_ of the table: and while Tom draws it
along one of its sides, do you, Louisa, at the same time, draw it along
the other.”
The children obeyed their father’s directions.
[Illustration: A piece of wood with two strings attached to it, and two
hands pulling the strings in diagonal directions.]
“See!” said Mr. Seymour, “the block obeys neither of the strings, but
picks out for itself a path which is intermediate. Can you tell me,
Tom, the exact direction which it takes?”
“If we consider this table as a parallelogram, I should say, that the
block described the diagonal.”
“Well said, my boy; the ablest mathematician could not have given a
more correct answer. The block was actuated by two forces at the same
time; and, since it could not move in two directions at once, it moved
under the _compound_ force, in a mean or diagonal direction,
proportioned to the influence of the joint forces acting upon it. You
will, therefore, be pleased to remember, it is a general law, that
where a body is actuated by two forces at the same time, whose
directions are inclined to each other, at any angle whatever, it will
not obey either of them, but move along the diagonal. In determining,
therefore, the course which a body will describe under the influence of
two such forces, we have nothing more to do than to draw lines which
show the direction and quantity of the two forces, and then to complete
the parallelogram by parallel lines, and its diagonal will be the path
of the body. I have here a diagram which may render the subject more
intelligible. Suppose the ball B were, at the same moment, struck by
two forces X and Y in the directions B A and B D. It is evident that
the ball would not obey either of such forces, but would move along the
oblique or diagonal line B C.”
[Illustration: Fig. 4. Force diagram for a ball moving in a diagonal
direction.]
“But,” said Tom, “why have you drawn the line B D so much longer than
B A?”
“I am glad you have asked that question. Lines are intended, not only
to represent the direction, but the _momenta_, or quantities of the
forces: the line B D is, as you observe, twice as long as B A; it
consequently denotes that the force Y acting in the direction B D, is
twice as great as the force X acting in the direction B A. Having
learned the direction which the body will take when influenced by joint
forces of this kind, can you tell me the relative time which it would
require for the performance of its diagonal journey?”
Tom hesitated; and Mr. Seymour relieved his embarrassment by informing
him, that it would pass along the diagonal in exactly the same space of
time that it would have required to traverse either of the sides of the
parallelogram, had but one force been applied. Thus, the ball B would
reach C in the same time that the force X would have sent it to A, or
the force Y to D. “I will endeavour to prove this fact beyond all
doubt. It is, I think, evident, that the force which acts in the
direction B A can neither accelerate nor retard the approach of the
body to the line D C, which is parallel to it; hence it will arrive at
C in the same time that it would have done had no motion been
communicated to it in the direction B A. In like manner, the motion in
the direction B D can neither make the body approach to nor recede from
A C; and it therefore follows, that, in consequence of the two motions,
the body will be found both in A C and C D, and will therefore be found
in C, the point of intersection.”
Louisa seemed to express by her looks the irksomeness of such
demonstrations; and which did not pass unobserved.
“This may appear tedious and uninteresting,” said Mr. Seymour, “but the
information is absolutely essential to our future progress: if you
would reap, you must sow.”
Tom and Louisa both expressed themselves willing to receive whatever
instruction their father might consider necessary; and they farther
declared, that they understood the demonstration he had just offered
them.
“Is it not then evident,” proceeded Mr. Seymour, “that the composition
of forces must always be attended with loss of power; since the
diagonal of a parallelogram can never, under any circumstances, be
equal to two of its sides? and is it not also evident, that the length
of the diagonal must diminish as the angles of the sides increase: so
that the more acute the angle at which the forces act, the less must be
the loss by composition? But I shall be better able to explain this law
by a diagram. If B A, A C be the sides of a parallelogram, representing
the direction of two forces, and A D the diagonal path of the body, is
it not evident that the line A D will shorten as the angle B A C
increases?”
[Illustration: Fig. 5. Three parallelograms, beginning with a square
and ending with a narrow diamond, all sharing one side.]
“We see that at once,” cried Tom, “from the diagram before us.”
[Illustration: Fig. 6. A square and a rectangle with a common diagonal.]
“Then we will proceed to another fact connected with the same subject.
Look at this diagram; is not the diagonal A D common to both the
parallelograms inscribed about it, viz. of A B C D, and A E F D?”
“To be sure it is.”
“Then it is equally clear, that a body may be made to traverse the same
path A D, by any pair of forces represented by the adjacent sides of
either of such parallelograms.”
“Undoubtedly.”
“I request you to keep that fact in your recollection.”
“I have now to inform you,” continued he, “that a single force may be
resolved into any number of forces, and may, in fact, be regarded as
compounded of innumerable oblique ones. In order, however, to render
this fact more intelligible, I must refer you to fig. 6, from which it
will appear that the motion of a body, along the line A D, will be the
same whether it arise from one single force acting in that direction,
or from two forces impressed upon it in the directions A B, A C, or in
those of A E, A F; and, consequently, although the motion may, in
reality, be the effect of a single force, yet it may be considered as
compounded of two or more in other directions, since the very same
motion would arise from such a composition.”
Tom acknowledged the truth of this statement; and Mr. Seymour assured
him, that, when they came to play at ball and marbles, he should be
able to give him a practical demonstration of the fact; for he would
show him, that whenever a body strikes a surface obliquely, or in an
inclined direction, such a _resolution of force_ will actually take
place: “and now, Tom,” said his father, “give me a marble; for I wish
to explain the reason why it turns round, or revolves on its axis, as
it proceeds forward.”
“I suppose,” said Tom, “it depends upon the action which I give to it
by my thumb and finger when I shoot it out of my hand.”
“You are, undoubtedly, capable of thus giving to your marble a certain
_spinning_ motion, the effect of which we shall have to consider
hereafter; but I fancy you would be greatly puzzled to make it proceed
without revolving, give it what impulse you might by your hand.”
“I have sometimes tried,” said Tom, “to make it do so by pushing it
along with a flat ruler, but it always _rolled_ in spite of me.”
[Illustration: Fig. 7. Diagram for marble’s motion.]
“Then it is clear, from your own experiment, that its rotation cannot
arise from the cause you would assign to it. If you will attend to this
diagram,” continued his father, “I will endeavour to explain the
operation. It is evident that, as the marble moves along the ground
B D, the motion of the point B will be retarded by the resistance
occasioned by its rubbing on the ground; while the point C, which does
not meet with any such resistance, is carried forward without
opposition, and it consequently must move faster than the point B; but
since all the parts of the marble cohere or stick together, the point C
cannot move faster than B, unless the marble revolves from C to E; and
as the several points of the marble which are successively applied to
the floor are retarded in their motion, while the opposite points move
freely, the marble during its progressive motion must continue to
revolve.”
“But you said, papa, that whenever a body moved in any direction,
except that of a straight line, it must have been acted upon by more
than one force; and yet the marble not only runs along the ground, but
turns round; at the same time, by the simple force of my hand.”
“The revolution of the marble, my dear boy, is brought about by no less
than three forces: look attentively at the diagram, and you will easily
comprehend my explanation. There is, in the first place, the
rectilinear motion given to it by your hand; then there is the friction
of the ground: since, however, this latter acts in a contrary
direction, it merely tends to lessen or counteract the velocity with
which the under-surface proceeds, and consequently to give a
relatively-increased progressive motion to its upper part; then comes
that force by which its several parts cohere, and which may be
represented by C H; so that the two forces producing the revolution of
the point C, are justly expressed by the lines C G, C H: but these are
in the direction of the two sides of a parallelogram, the point will
therefore move along the diagonal C E. I have here a toy for you, which
will serve to explain still farther the causes of rotation to which I
have alluded.” Mr. Seymour produced a watch-glass, in the hollow of
which stood a dancing-figure of thin card, as here represented.
[Illustration: Toy man standing on the flat part of a convex piece of
glass.]
He placed it upon a black japanned waiter,[16] which he held in an
inclined position, when it immediately slided down the inclined plane,
as might have been expected. He next let fall a drop of water upon the
waiter, and placed the watch-glass in it. Under this new arrangement,
instead of sliding, the watch-glass began to revolve as soon as an
inclination was given to the surface; and it continued to revolve with
an accelerated velocity, obeying the inclination and position of the
plane, as directed by the hand of the operator.
“What a very pretty effect is produced by the rapid revolution of the
figure!” observed Louisa.
“Its use in the arrangement,” said her father, “is to render the
accelerated motion more obvious.”
“I perceive it revolves faster and faster, or, I suppose I ought to
say, with an accelerated velocity,” said Tom.
“Certainly,” answered Mr. Seymour; “whenever a force continues to act,
the motion produced by it must be accelerated for the reason already
given you[17]--but let me explain the operation of the drop of water,
which, as you have just seen, converted the sliding into the revolving
motion. In the first place, in consequence of the cohesion of the water
to the two surfaces, a new force was introduced, by which an unequal
degree of resistance was imparted to different portions of that part of
the watch-glass in contact with the plane, and, consequently, in its
effort to slide down, it necessarily revolved. Now, if you will
attentively observe the change of figure which the drop of water
undergoes during the revolution of the glass, you will perceive a
species of vortex; a film of water, by capillary action, is drawn to
the foremost portion of the glass, while, by the centrifugal force, a
body of water is thrown under the hinder part of it; the effect of both
these actions is to accelerate the rotatory motion.
“I shall now dismiss the subject for the present, but on some future
occasion I shall probably revert to it; for it may be made to afford a
simple illustration of the rotatory and progressive motions of the
earth round the sun; and it may also give us the means of producing
some optical effects of a very curious kind.”(15)
Mrs. Seymour here suggested that, as it was past one o’clock, the
children should be dismissed to their more active sports in the garden.
“We will instantly proceed to the lawn,” replied Mr. Seymour, “and Tom
may try his skill with the _sling_; an amusement which I have provided
as a reward for his industry, and which will, at the same time, convey
some farther information concerning the nature of those forces we have
been just considering. The sling,” continued his father, as he advanced
upon the lawn, “consists, as you perceive, of a leathern thong,
broadest in the middle, and tapering off gradually towards both ends.
To each extremity is affixed a piece of string. I shall now place a
stone in the broad part of the leather, and introduce my middle finger
into the loop formed in one of the strings, and hold the other
extremity between my fore-finger and thumb.”
He then whirled it round, and when it had gained sufficient impetus, he
let go his hold of the string, and the stone instantly shot forth with
amazing velocity.
“See! see! there it goes,” exclaimed Tom; “to what a height it
ascended!”
“And to what a distance has it been projected!” observed Louisa, who
had attentively watched its descent.
“Now, Tom,” said his father, “can you explain the operation you have
just witnessed?”
“Not exactly, papa.”
“Then attend to me. Have you not learned that circular motion is always
the result of two forces?”
“Undoubtedly,” replied Tom; “of one force which attracts it to the
centre around which it moves, and of another which impels it to move
off in a right line.”
“Certainly; the former of these forces is, therefore, termed the
_centripetal_, because it draws the body towards the centre, while the
latter is called the _centrifugal_ force, since its influence disposes
the body to fly off from the centre. In circular motion, these two
forces constantly balance each other; otherwise it is evident that the
revolving body must either approach the centre or recede from it,
according as the one or the other prevailed. When I whirled round the
sling, I imparted a projectile force to the stone, but it was prevented
from flying off in consequence of the counteracting or _centripetal_
force of the string; but the moment I let go my hold of this, the stone
flew off in a right line: having been released from confinement to the
fixed or central point, it was acted upon by one force only, and motion
produced by a single force is, as you have just stated, always in a
right line.”
“But,” observed Louisa, “the stone did not proceed in a straight, but
in a curved line: I watched its direction from the moment it left the
sling till it fell to the ground.”
“You are perfectly correct,” replied Mr. Seymour, “it described a
curve, which is called a _parabola_; but that was owing to the
influence of a new force which came into play, viz. that of gravity,
the effect of which I shall have to explain hereafter.”
“I cannot understand,” said Tom, “why the stone should not have fallen
out of the sling when you whirled it round over your head.”
“Because, my dear, it was acted upon by the _centrifugal_ force, which
counteracted that of gravity: but I will render this fact more evident,
by a very simple and beautiful experiment. I have here a wine-glass,
around the rim of which I shall attach a piece of string so as to
enable me to whirl it round. I will now fill it with water, and
although during one part of its revolution it will be actually
inverted, you will find that I shall not spill a single drop of water.”
Mr. Seymour then whirled round the glass, and the young party were
delighted with the confirmation thus afforded to their father’s
statement.
“I see,” said Tom, “how it happened: when the glass was inverted the
water could not fall out, because it was influenced by the centrifugal
force which opposed gravity.”
“Exactly. Have you ever observed what happens during the trundling of a
mop? The threads which compose it fly off from the centre, but being
confined to it at one end they cannot part from it: while the water
which they contain being unconfined, is thrown off in right lines.”
“I have certainly observed what you state,” said Louisa; “the water
flies off in all directions from the mop.”
“Yes,” added Tom, “the water was not acted upon by the _centripetal_
force as the threads were, and consequently, there was nothing to check
the _centrifugal_ force, which carried the water off in a straight line
from the centre.”
“You are not quite correct,” said Mr. Seymour; “the water does not fly
off in a right line from the centre, but in a right line in the
direction in which it was moving at the instant of its release; the
line which a body will always describe under such circumstances, is
called a _tangent_, because it _touches_ the circumference of the
circle, and forms a right-angle with a line drawn from that point of
the circumference to the centre: but I will render this subject more
intelligible by a diagram.
“Suppose a body, revolving in the circle, was liberated at _a_, it
would fly off in the direction _ab_; if at _c_, in that of _cd_; and if
at _e_, in that of _ef_; and so on. Now, if you draw lines from these
several points to the centre of the circle, you will perceive that such
lines will form, in each case, a right-angle. In the experiment which
you have just witnessed, the surface of the water must have formed,
during its revolution, a right-angle with the string, and consequently
could not have fallen out of the wine-glass. A knowledge of this law,”
continued Mr. Seymour, “will explain many appearances which, although
familiar, I dare say, have never been understood by you. You may
remember accompanying me to the pottery, to see the operation of the
turning-lathe; it was owing to the centrifugal force produced by the
rotation of the wheel, that the clay, under a gentle pressure, swelled
out so regularly; from a similar cause, the flour is thrown out of the
revolving mill as fast as it is ground; and I shall presently show you
that you are indebted to this same force for the spinning of your top
and the trundling of your hoop. But let us quit this subject for the
present, and pursue the stone in its course after it is liberated from
the sling. Louisa has justly observed that it described a curve; can
you explain why it should deviate from a straight line?”
[Illustration: Fig. 8. Diagram for centrifugal force.]
“Let me see,” said Tom, thoughtfully; “it would be acted upon by two
forces, one carrying it forward in a right line, the other bringing it
to the earth; it would, therefore, not obey either, but describe a
diagonal: but why that diagonal should be a curve I cannot exactly
explain.”
“Then I will give you the reason,” said his father. “A stone projected
into the air is acted upon by no less than three forces; the force of
projection, which is communicated to it by the hand or the sling; the
resistance of the air through which it passes, and which diminishes its
velocity without changing its direction; and the force of gravity,
which ultimately brings it to the ground. Now, since the power of
gravity and the resistance of the air will always be greater than any
force of projection we can give a body, the latter must be gradually
overcome, and the body brought to the ground; but the stronger the
projectile force, the longer will those powers be in subduing it, and
the farther will the body go before it falls. A shot fired from a
cannon, for instance, will go much farther than a stone thrown from
your hand. Had the two forces which acted upon the stone, viz. those of
projection and gravity, both produced uniform motion, the body must
certainly have descended through the diagonal; but since gravity, as
you have already learned, is an accelerating force, the body is made to
describe a curve instead of a straight line.
“This law, however, will require the aid of a diagram for its
explanation. Let X represent the ball at its greatest altitude, X Y the
force of gravity drawing it downward; and X Z that of projection. We
have here, then, two forces acting in the direction of the two sides of
a parallelogram. In passing on to Z, the ball will perform the diagonal
X _a_; and in the next equal space of time, will descend through
_three_ times the distance Z _a_, and will consequently be found at
_b_; while in the next period it will fall through _five_ equal spaces,
and pass to _c_; and in the next period, again, as it must fall _seven_
such spaces, it will reach the ground at _d_, having described a
portion of a curve from X to _d_, or during the time that the two
forces were in simultaneous operation. The same principle will explain
the curved ascent of the ball, substituting only the laws of retarded
for those of accelerated motion; for it is clear, that the body during
its _ascent_, will be retarded in the same degree in which it was
accelerated during its _descent_.”
[Illustration: Fig. 9. Diagram of a parabolic flight path.]
“Your explanation,” said Louisa, “appears very clear and satisfactory.”
“The curve which _Projectiles_ (that is to say, bodies projected into
the air) describe, is termed a _Parabola_ (16), although the resistance
of the air, which is not recognised in the theory, produces a
considerable influence on the practical result.”
The children now proceeded to amuse themselves with the sling. Louisa
challenged Tom to a trial of skill. She fancied that she could hurl a
stone with greater accuracy than her brother; but after several
contests she acknowledged herself vanquished, for Tom had succeeded in
striking the trunk of an old tree at a considerable distance, while his
sister was never able to throw the stone within several yards of the
mark.
“Well done, Tom!” exclaimed Mr. Seymour; “why you will soon equal in
skill the ancient natives of the Balearic Islands!”
“And were they famous for this art?” asked Louisa.
“With such dexterity,” replied her father, “did they use the sling,
that we are told their young children were not allowed any food by
their mothers, except that which they could fling down from the beam
where it was placed aloft. I fancy, however, Tom, that you would become
very hungry before you could strike an object in yonder poplar.”
“At all events, I will try,” said Tom.
He accordingly whirled round his sling, and discharged stone, which
flew forward with great velocity, but in a direction very wide from the
mark at which it was aimed. In the next moment a violent hallooing was
heard: it was from the vicar, who had narrowly escaped the boisterous
salutation of the falling stone, which, in its anxiety to throw itself
at the feet of the reverend gentleman, struck the beaver penthouse that
defended his upper story, and by a resolution of forces which we have
endeavoured to explain, darted off in the direction of the side of a
parallelogram, and was thus averted from the equally sensitive
antipodes of his venerable person, the brains in his head, and the
corns in his shoes.
“Upon my word, young gentleman!” cried the vicar, “I expected nothing
less than the fate of the giant of Gath.”
“My dear Mr. Twaddleton,” exclaimed Tom, in a tone of alarm, “I
sincerely hope that you have not been struck?”
“O no! thanks to my clerical helmet, I have escaped the danger which
threatened me: but, tell me, what new game is engaging your attention?”
Mr. Seymour said that he had been explaining the scientific principle
of the sling, and that he hoped the vicar was prepared to afford them
some information respecting its invention and history.
“The sling?” repeated the vicar; “why, bless me! I left you discoursing
upon elasticity; you really stride over province after province as
rapidly as if you were gifted with the seven-leagued boots of the
Ogre:--but to the point in question. The art of slinging, or casting
stones, is one of the highest antiquity, and was carried to a great
degree of perfection amongst the Asiatic nations. It was well known and
practised at a very early period in Europe; and our Saxon ancestors
appear to have been very expert in the use of this missile.”
Mr. Twaddleton, being desirous of communicating history of Major
Snapwell, begged that Mr. and Mrs. Seymour would allow him a few
minutes’ conversation; observing that the attention of the children
would be agreeably occupied during their absence by their
newly-acquired amusement.
“We will then, if you please, vicar,” replied Mr. Seymour, “walk to the
Geological Temple, where I have lately deposited some specimens which
you have not yet seen.”
“To speak sincerely,” said the vicar, “I cannot participate in that
high satisfaction which you appear to feel in collecting such hoards of
broken rocks and pebbles: where can lie the utility of such labour?
unless, indeed, in pursuance of your Utopian plans, you intend to
_Mac-adamise_ all the roads of science.”
“Is it nothing, my dear Mr. Twaddleton, to discover the structure of
different countries?”
“Which the geologist infers,” replied the vicar, “from a few
_patterns_, picked up at random on the road side!”
“Mr. Twaddleton,” said Mr. Seymour, “I will meet you on your own
ground: you are an antiquary; if an ancient monument of art be so
inestimable, is not a knowledge of the antiquity of the globe itself,
at least, of equal interest?”
“I understand you: you would infer that the scriptural account of the
Deluge is disproved by those Sciolists, who pretend to discover the
antiquity of the globe by penetrating its caverns, with as much ease as
the jockey ascertains the age of a horse by looking into its jaws.”
“You speak too flippantly of a class of philosophers who have united
their efforts to investigate a sublime subject upon the true principles
of science; were you to attend the meetings of the Geological Society,
and hear the discussions of its members, you would cease to talk thus
irreverently.”
“Although I may be unknown to your genii of the mountains, I am, at
all events, acquainted with a kindred class of philosophers who rival
them in industry, if not in talents; and notwithstanding the limited
range of their observations--being confined to the mountainous
districts they inhabit--I have little doubt but that their labours
have proved as acceptable to the world as those of the disciples of
Hutton or Werner. I once visited this district, and although the
language of its inhabitants was entirely unknown to me, I soon
discovered, by the aid of a glass, that they were in serious
discourse with each other; and one of the elders of the fraternity,
who was seated on a craggy precipice that overhung an extensive
valley covered with rich verdure, appeared, from his gestures, as if
pointing out to his fellow-labourers, who were digging in all
directions in search of treasure, the danger of an approaching
convulsion. While I was yet gazing, the fatal catastrophe actually
occurred; immense masses of the tottering strata rolled with
precipitous haste into the valley, involving in its ruin hundreds of
its inhabitants. It was extraordinary to behold the effects of this
shock upon those who were beyond the reach of its more destructive
influence; hundreds were seen scaling heights that appeared
inaccessible; others, stumbling--falling down frightful
precipices--rising again--helping, or pushing each other on--the
foremost serving as so many stepping-stones to those behind, who, in
their turn, hauled up the clusters over whose backs they had so
unceremoniously vaulted.”
“How awful!” cried Mrs. Seymour; “I never heard of any modern
catastrophe of such fearful extent: where did it occur?”
“The vicar doubtless alludes to the terrible earthquake of Messina, or
perhaps to that of Lisbon.”
“I neither allude to the one nor to the other,” cried Mr. Twaddleton;
“and yet, in some respects, the catastrophe which I have described
resembled that of Lisbon; for during the dreadful disaster human beings
seen to take advantage of the confusion to murder many of the
inhabitants, and to pillage their territories.”(17)
“For goodness’ sake!” cried Mrs. Seymour, “tell us at once where this
terrible event occurred.”
“In a fine Cheshire cheese!” exclaimed the vicar, “which had furnished
abundant food to the miniature republic of mites that occupied its deep
ravines and alpine heights. I think now,” continued the reverend
gentleman, “I am amply revenged for the allegorical jokes in which Mr.
Seymour has so often indulged at my expense.”
“I am well satisfied,” said Mr. Seymour; “for by repeating your
allegory to my children, I shall be enabled to convey a striking lesson
of wisdom. They will learn from it that there is not any pursuit,
however exalted, that may not be assailed by the weapons of ridicule,
especially when wielded by those penurious philosophers whose ideas of
utility are circumscribed within the narrow limits of direct and
immediate profit.”
“It is too true,” cried Mrs. Seymour, “that we are all apt to
depreciate those branches of knowledge which do not bear directly upon
the comforts or necessities of life; and the applications of geology
are, perhaps, so remote as scarcely to be discovered by the mass of
mankind.”
“There I must differ with you,” replied her husband: “to say nothing of
the practical advantages which have accrued to the miner from this
study, it has been the means of bringing hundreds of acres into
cultivation in districts where never a blade of grass had before
grown;(18) and if scholastic researches have thrown additional light on
scriptural subjects, they are no more to be compared with those of the
geologist on these occasions, than is the light of the glow-worm to
that of the sun.”
“Hey-day! what do I hear?” exclaimed the vicar. “Would you compare the
testimony of the Apamean medal with that of an unshapen flint?”
“I would rest my faith upon a _rock_,” replied Mr. Seymour; “the caves
of Buckland(19) have done more towards supporting the Mosaic account of
the Deluge than all the medals of the virtuoso. Fossils, in truth, are
to the geologist what medals are to the antiquary, preserving a record
of events which must otherwise have perished in the stream of time.”
Mr. and Mrs. Seymour and the vicar by this time arrived at the
Wernerian Temple, where, having discussed several points connected with
its objects, Mr. Twaddleton gave an account of Major Snapwell, whose
history created considerable interest, and determined Mr. Seymour to
call at Ivy Cottage, and invite its inmate to the Lodge.
[Illustration: Rock teetering on a ledge.]
-----
Footnote 16:
Footnote 16: A common plate will answer the purpose; but the black
surface gives the advantage of exhibiting more perfectly the motion
of the water during the progress of the experiment.
Footnote 17:
See page 54.
------------------------------------------------------------------------
[Illustration: Two boys rolling hoops along the ground using sticks.]
CHAPTER VIII.
_The subject of Rotatory Motion continued.--A Ball, by having a
peculiar spinning motion imparted to it, may be made to stop
short, or to retrograde, though it meets not with any apparent
obstacle.--The rectilinear path of a Spherical Body influenced
by its rotatory motion.--Bilboquet, or Cup and Ball.--The joint
forces which enable the Balancer to throw up and catch his Balls
on the full gallop.--The Hoop.--The Centre of Percussion.--The
Whip and Peg-top.--Historical Notices.--The power by which the
Top is enabled to sustain its vertical position during the act
of spinning.--The sleeping of the Top explained.--The force
which enables it to rise from an oblique into a vertical
position.--Its gyration._
“Tom, do you remember that I told you a few days ago,” said Mr.
Seymour, “that, by giving a revolving body a peculiar _spinning_
motion, certain effects were produced, which I should, on some future
occasion, take into consideration?”
“To be sure I do,” replied Tom.
“Well, then, attend to me.”
Mr. Seymour took a marble, and, placing it on the ground, gave it an
impulse forward by pressing his forefinger upon it: the marble darted
forward a few paces, after which it rolled back again.
“That is most extraordinary!” cried Tom; “the marble came back to your
hand, as it were, of its own accord, and without having met with any
obstacle.”
“And you, no doubt,” said Mr. Seymour, “regard it as contrary to the
well known law, that a body once put in motion, in any direction, will
continue to move in that direction until some foreign cause oppose it.”
“It really would appear so.”
“It is, however, far otherwise; the force which I imparted to the
marble communicated to it two kinds of motion; the one projecting it
forward, the other producing a rotatory motion round its axis, in a
direction opposite to that of its rectilinear course; and the
consequence was simply this, that when the former motion, on account of
the friction of the marble on the ground, was destroyed, the rotatory
motion continued, and by thus establishing an action in an opposite
direction, caused the marble to retrograde. If, however, you will fetch
your hoop, I will demonstrate the fact on a larger scale.”
Tom accordingly produced the hoop; and Mr. Seymour projected it
forward, giving to it, at the same instant, a spinning motion in an
opposite direction. The hoop proceeded forward to a certain distance,
when it stopped, and then ran back to the hand.
“Let me beg you,” said Mr. Seymour, “to treasure this fact in your
memory; you perceive by it how greatly the progressive direction of a
body may be influenced by a rotatory motion around its axis; and,
indeed, the theory of the _rifle_ gun(20) is easily deduced from it. It
will also explain the effect which a rotatory motion produces in
steadying or disturbing the direction of a projectile. It is for such a
reason that the balancer constantly whirls round his balls or oranges,
as he throws them into the air, with the intention of catching them
again; and that in playing at _Bilboquet_, or cup and ball, you find it
necessary to give a spinning motion to the ball, in order to catch it
on the spike--but we will consider this subject presently. I am now
desirous of laying down a few propositions upon the subject of
rotation, the knowledge of which is essential for the explanation of
the motions of revolving bodies.”
Mr. Seymour proceeded to state that every body had three principal axes
upon which it might revolve, but that the shortest was the only one
upon which it could permanently and steadily rotate--that should it, in
consequence of the impulse given to it, begin to spin upon any other
than the shortest axis, it would, during its revolutions, be constantly
showing a tendency to approach it; whence it followed that, under such
circumstances, it would be unsteady and _wabbling_ in its motions.
In order, however, to make this proposition intelligible to the
children, Mr. Seymour performed the following simple experiment.
[Illustration: Two rings, labeled 1 and 2.]
Having tied some string to a common curtain ring, as represented by
figure 1, he twisted it round by means of his thumb and finger, until
it acquired considerable velocity, when the ring was seen to rise
gradually into the position represented by fig. 2. Thus, in the
simplest manner, was a revolving body shown to exchange its longer for
its shorter axis.
The children declared that they perfectly comprehended the subject, and
Tom observed that, in future, whenever he wished to make a ball spin
steadily, he should take care to make it turn on its shortest axis.
“You are quite right, Tom,” said Mr. Seymour; “and the skilful bowler
at cricket, in order to give his ball a steady axis of rotation, always
holds it with the seam across, so that the tips of his fingers may
touch, and he takes care to hold it only with such a grasp as may be
sufficient to steady it, for by a turn even of the wrist it may be made
to proceed unsteadily; and this leads me to consider another equally
important proposition--viz. that the axis of rotation should coincide
with the direction in which it is moving forward, or, in other words,
with its line of motion. Now, where this is not the case, it is evident
that the unequal action of the air will cause the body to deviate from
its straight course, since its two sides, having different velocities
(the rotatory and progressive motions conspiring on one side, while
they are in opposition on the other), will be differently affected by
such resistance; the resistance, of course, increasing with the
velocity. It is upon this principle,” continued Mr. Seymour, “that Sir
Isaac Newton has explained the irregular motion of the tennis-ball.”
“But do explain to us, papa,” said Louisa, “why it is so necessary to
spin the ball in order to catch it on the spike?”
“Rotatory motion, my dear, when directed according to the principles I
have endeavoured to enforce, will always steady the course of a body.
In playing at bilboquet, your object is so to throw up the ball that
its hole may descend perpendicularly upon the spike which is held for
its reception; and in order to accomplish this, you make the ball spin
upon an axis, at the extremity of which is the hole; the consequence is
obvious.”
Louisa observed, that she well remembered an allusion to this game in
Miss Edgeworth’s Essays on Education; and that, unless she was much
deceived, the advantage to be gained by spinning the ball was referred
to centrifugal force, and its effect in preserving the “_parallelism of
motion_.”
“I do not recollect the passage,” answered her father, “but I will
admit that the centrifugal force is indirectly instrumental to the
effect, although, in my view of the subject, it is more philosophical
to refer it at once to the creation of an appropriate axis of rotation.”
“I well remember,” observed Tom, “that the rider at Astley’s whirled
round the oranges as he threw them into the air.”
“And I hope that you are now not only acquainted with the principle
which rendered such a rotatory motion necessary, but that which must
make the shorter the more eligible axis for effecting his purpose;--but
can you tell me how it could have happened, that the oranges, which
were thrown perpendicularly upwards while the horseman was on the full
gallop, should have fallen again into his hand?”
“Ay,” said Louisa, “that puzzled me exceedingly; I should have thought
he would have ridden away from them, and that they must have fallen
several feet behind him.”
“What say you, Tom, to that?” enquired Mr. Seymour.
“I suppose,” replied Tom, “that the rider calculated upon the distance
he would pass forward before they could fall, and projected them
accordingly.”
“No, indeed; there is no calculation in the case, nor is any art used
to throw the oranges in advance: they are projected perpendicularly
from the hand; and if you will only recall to your mind the subject of
the ‘Composition of Forces,’ the mystery will vanish.”
“I see it all clearly,” cried Tom; “the orange partakes of the
progressive motion of the rider; when, therefore, he throws it upwards,
it is influenced by two forces which are in the direction of the two
sides of a parallelogram, and it consequently describes the diagonal.”
“You are quite right; but you doubtless will perceive that, instead of
a straight line, the orange will describe a parabolic curve.”
“For the same reason, I suppose,” said Tom, “that the stone from the
sling described a curve?”
“Certainly; but see, I have a diagram which will explain the subject
more clearly.”
[Illustration: A man on a moving horse demonstrates progressive motion
with an orange.]
“The orange, as it is thrown into the air, is influenced by two forces:
the one arising from the progressive motion of the rider, the other
from the projectile force imparted to it. These two forces are in the
direction of the adjacent sides of a parallelogram, and were it not for
the operation of gravity, the body would accordingly describe its
diagonal in the same space of time as it would have described one of
the sides.[18] The influence of gravity, however, not only deflects it
from a right line into a curve, but diminishes its force, so that
instead of arriving at the opposite angle of the parallelogram _a_, its
greatest altitude will be short of that point; it will then descend
through a similar curve; and, since the times of ascent and descent are
equal,[19] it will reach the hand of the rider at the very moment he is
prepared to receive it; for the orange will have traversed the
parabolic curve in the same space of time as the horseman required for
passing from one extremity of the curve to the other.”
Mr. Seymour having concluded this explanation, much to the satisfaction
of the young party, observed that the present occasion was an
appropriate one for the introduction of some remarks on the favourite
pastime of the HOOP.
“It is a classical pastime,” exclaimed the vicar, “and was as common
with the Greeks and Romans as it is with boys of the present
generation.”
“And it has the advantage,” added Mr. Seymour, “of sending the tide of
life in healthful currents through the veins.”
Tom began to trundle his hoop along the gravel walk.
“Stop, stop, my dear boy,” cried his father, “you seem to have
forgotten our compact, that every toy should be fairly won before it
was played with. Come upon the lawn, and let me ask you some questions
relative to the motions of the hoop. Can you make it stand still upon
its edge?”
“Not readily,” was Tom’s reply.
“And yet,” continued Mr. Seymour, “during its progressive motion, it
rolls on its edge without any disposition to fall: how happens that?”
“It is owing to the centrifugal force, which gives it a motion in the
direction of a _tangent_ to the circle, and, consequently, overcomes
the force of gravity.”
“Your answer is pat,” replied his father: “as long as you give your
hoop a certain degree of velocity, the _tangential_, or centrifugal
force, overcomes gravity, in the manner you have already witnessed;[20]
but, when that is slackened, the hoop will fall on its side; not,
however, until it has made several complete revolutions. Now, answer me
another question. Why is it so difficult to make the hoop proceed
straight forward, without turning to the right or left?”
“I suppose it arises from the same cause as that which altered the
direction of my marble as it ran along--the inequality of the ground.”
“That,” replied his father, “would undoubtedly have its influence; but
it is principally to be referred to the impossibility of your
constantly giving a straight blow by the stick. When it is moving
forward, a slight inclination towards either side will cause the parts
to acquire a motion towards that side, those which are uppermost being
most affected by it; and this lateral, or sideway motion, assisted
sometimes by the irregular curvature of the hoop, causes its path to
deviate from a rectilinear direction; so that, instead of moving
straight forward, it turns to that side towards which it began to
incline; and, in this position, its tendency to fall is still farther
counteracted by the centrifugal force. It is from a similar cause that
the bullet, unless rifled, will have a tendency to go to the right or
left, from any unequal impulse which it may have received at the moment
of its exit from the barrel. I have yet one other question, and, as its
answer will lead us into the consideration of a mechanical subject of
some importance, I must beg you to bestow all your attention. In
trundling your hoop, have you not often observed that, although the
blow inflicted upon it by your stick might have been violent, yet the
effect produced by it was comparatively small, in consequence of the
hoop having been struck by a disadvantageous part of the stick?”
“Certainly! I have frequently observed that, if the hoop is struck by
the stick either too near the hand, or too near the end, much of its
force is lost; and I have also noticed the same thing in striking the
ball with my cricket-bat.”
“The fact is,” said Mr. Seymour, “that every striking body has what is
termed its _centre of percussion_, in which all the percutient force of
a body is, as it were, collected; thus, a stick of a cylindrical
figure, supposing the centre of motion at the hand, will strike the
greatest blow at a point about two-thirds of its length from the wrist.
I may, perhaps, at some future time, return to this subject, and
explain several mechanical effects which are dependent upon it.(21) Now
away with you, and trundle your hoop, or spin your top; as soon as the
vicar arrives I will rejoin you.”
In the course of an hour Mr. Seymour and his reverend friend proceeded
to the play-ground, where they found the children busily engaged in
their several diversions.
“I rejoice to find you at so classical a pastime,” said the vicar, as
he approached Tom, who was busily engaged in spinning his top. “The
top, my boy, is a subject which the great Mantuan bard did not consider
beneath the patronage of his muse: but, hey-day! this is not the
‘_volitans sub verbere turbo_’ of the immortal Virgil; the top of
antiquity was the whip-top, the peg-top is a barbarous innovation of
modern times: a practical proof of the degeneracy of the race. Even
boys, forsooth, must now-a-days have their activity cramped by
inventions to supersede labour: well may we regard the weapons, which
our sturdy ancestors wielded as instruments rather calculated for
giants than men, if such pains be taken to instil into the minds of
youth the mischievous spirit of idleness.”
“My dear sir,” said Tom, who was always grieved at displeasing the
vicar, “if it will gratify you, I will spin my _whip_-top, for I have
an excellent one which my papa has lately given me.”
“Well said! my dear boy. ‘_Puer bonæ spei._’--What a pity would it be
to damp so noble a spirit; get your whip-top.”
Tom accordingly placed the Virgilian top upon the ground, and as the
boy plied the whip, so did the vicar lash the air with his quotation;
running round the top in apparent ecstasy, while he repeated the
well-known lines from the seventh Æneid:--
“Ille actus habena
Curvatis fertur spatiis; stupet inscia turba,
Impubesque manus, mirata volubile buxum:
Dant animos plagæ.”[21]
As Mr. Twaddleton thus gave vent to that fervour which was ever kindled
by collision with Virgil, Tom gave motion to his top, which swaggered
about with such an air of self-importance, that, to the eye of fancy,
it might have appeared as if proudly conscious of the encomiums that
had been so liberally lavished upon it.
“The Grecian boys, as Suidas informs us, played also with this top,”
continued the vicar.
“And pray, may I ask,” said Mr. Seymour, “whether it was not introduced
into this country by the Romans?”
“Probably,” replied the vicar. “Figures representing boys in the act of
whipping their tops first appear in the marginal paintings of the
manuscripts of the fourteenth century; at which period, the form of the
toy was the same as it is at present, and the manner of impelling it by
the whip can admit of but little if any difference. In a
manuscript,[22] at the British Museum, I have read a very curious
anecdote which refers to Prince Henry, the eldest son of James the
First; with your permission I will relate it to you.”
Here the vicar extracted a memorandum-book from his pocket, and read
the following note:--
“The first tyme that he, the prince, went to the towne of Sterling to
meete the king, seeing a little without the gate of the towne a stack
of corne, in proportion not unlike to a topp, wherewith he used to
play, he said to some that were with him, ‘Loe there is a goodly topp:’
whereupon one of them saying, ‘Why doe you not play with it then?’ he
answered, ‘Set you it up for me, and I will play with it.’”
“Was not that a clever retort of the young prince?” said the vicar, as
he returned the manuscript into his memorandum-book; “and I think it
must have confounded the courtier who could have asked so silly a
question.”
“Well, Tom,” said Mr. Seymour, “let us see whether you can set up your
own top, so that it shall stand steadily on its point.”
“I have often tried that experiment,” answered Tom, “but could never
succeed in keeping the line of direction within its narrow base.”
“And yet, when in rotatory motion, its erect position is maintained
without difficulty; how is that?”
“Is it not owing to the centrifugal force?” asked Tom.
“Undoubtedly: but as the subject is highly interesting, I will
endeavour to explain it more fully. You must, however, first obtain
permission from the vicar to spin your humming-top, for that will
better illustrate the phenomena which it is my wish to examine.”
“If your object is the exercise of the body, let us spin the whip-top,”
replied the vicar; “but if you wish to exercise the boy’s mind, I
cannot object to your selecting the top best calculated to fulfil that
desire.”
Tom, having accordingly prepared his top, pulled the string, and set
the wooden machine spinning on the floor.
“Now, Tom, I will explain to you the reason of the top being able to
sustain its vertical position. You have already learned, from the
action of the sling, that a body cannot move in a circular path,
without making an effort to fly off in a right line from the
centre;[23] so that, if a body be affixed to a string, and whirled
round by the hand, it will stretch it, and in a greater degree
according as the circular motion is more rapid.”
“Certainly,” said Tom.
“The top, then, being in motion, all its parts tend to recede from the
axis, and with greater force the more rapidly it revolves: hence it
follows that these parts are like so many powers acting in a direction
perpendicular to the axis; but, as they are all equal, and as they pass
all round with rapidity by the rotation, the result must be that the
top is in equilibrio on its point of support, or on the extremity of
the axis on which it turns. But see, your top is down.”
“And what is the reason,” asked Tom, “of its motion being stopped?”
“I can answer that question, papa,” said Louisa; “is it not owing to
the friction of the ground?”
“Certainly; that has, doubtless, its influence: but the resistance of
the air is also a powerful force upon this occasion. A top has been
made to spin in vacuo as long as two hours and sixteen minutes.[24] But
come, Tom, spin your top once more. Observe,” exclaimed Mr. Seymour,
“how obliquely the top is spinning. It is now gradually rising out of
an oblique position;--now it is steadily spinning on a vertical
axis;--and now its motion is so steady, that it scarcely seems to move.”
“It is _sleeping_, as we call it,” said Tom.
“Its centre of gravity is now situated perpendicularly over its point
of support, which is the extremity of the axis of rotation: but attend
to me,” continued Mr. Seymour, “for I am about to attempt the
explanation of a phenomenon which has puzzled many older and wiser
philosophers than yourselves. It is evident that the top, in rising
from an oblique to a vertical position, must have its centre of gravity
raised; what can have been the force which effected this change?”
“Was it the centrifugal force?” asked Tom.
“Certainly not,” said Mr. Seymour, “as I will presently convince you.”
“Then it must have been the resistance of the air,” said Louisa.
“No; nor was it the resistance of the air,” replied her father: “for
the same effect takes place in vacuo.”
“Then pray inform us, by what means the top was raised.”
[Illustration: A toy top, diagonal to a surface.]
“It entirely depended upon the form of the extremity of the peg, and
not upon any simple effect connected with the rotatory or centrifugal
force of the top. I will first satisfy you that, were the peg to
terminate in a fine, that is to say, in a _mathematical_ point, the top
never could raise itself. Let A B C be a top spinning in an oblique
position, having the end of the peg, on which it spins, brought to a
fine point. It will continue to spin in the direction in which it
reaches the ground, without the least tendency to rise into a more
vertical position; and it is by its rotatory or centrifugal force that
it is kept in this original position: for if we conceive the top
divided into two equal parts A and B, by a plane passing through the
line X C, and suppose that at any moment during its spinning, the
connection between these two parts were suddenly dissolved, then would
any point in the part A fly off with the given force in the direction
of the tangent, and any corresponding point in the part B with an equal
force in an opposite direction; whilst, therefore, these two parts
remain connected together, during the spinning of the top, these two
equal and opposite forces A and B will balance each other, and the top
will continue to spin on its original axis. Having thus shown that the
rotatory or centrifugal force can never make the top rise from an
oblique to a vertical position, I shall proceed to explain the true
cause of this change, and I trust you will be satisfied that it depends
upon the bluntness of the point. Let A B C be a top spinning in an
oblique position, terminating in a very short point with a
hemispherical shoulder P _a_ M. It is evident that, in this case, the
top will not spin upon _a_ the end of the true axis X _a_, but upon P,
a point in the circle P M, to which the floor I F is a tangent.
Instead, therefore, of revolving upon a fixed and stationary point, the
top will roll round upon the small circle P M on its blunt point, with
very considerable friction, the force of which may be represented by a
line O P at right angles to the floor I F, and to the spherical end of
the peg of the top: now it is the action of this force, by its pressure
on one side of the blunt point of the top, which causes it to rise in a
vertical direction. Produce the line O P till it meets the axis C; from
the point C draw the line C T perpendicular to the axis _a_ X, and T O
parallel to it; and then, by a resolution of forces, the line T C will
represent that part of the friction which presses at right angles to
the axis, so as gradually to raise it in a vertical position; in which
operation the circle P M gradually diminishes by the approach of the
point P to _a_, as the axis becomes more perpendicular, and vanishes
when the point P coincides with the point _a_, that is to say, when the
top has arrived at its vertical position, where it will continue to
_sleep_, without much friction, or any other disturbing force, until
its rotatory motion fails, and its side is brought to the earth by the
force of gravity.”
[Illustration: A top diagonal to a surface, with a diagram describing
its rotation.]
“I _think_ I understand it,” said Tom, “although I have some doubt
about it; but if you would be so kind as to give me the demonstration
in writing, I will diligently study it.”
“Most readily,” said Mr. Seymour. “Indeed I cannot expect that you
should comprehend so difficult a subject, without the most patient
investigation; and, in the present state of your knowledge, I am
compelled to omit the relation of several very important circumstances,
to which I may, hereafter, direct your attention. When, for instance,
you have become acquainted with the elements of astronomy, I shall be
able to show you that the gyration of the top depends upon the same
principles as the precession of the equinoxes.”(22)
[Illustration: Two boys spin a top with whips.]
-----
Footnote 18:
See page 119.
Footnote 19:
See page 54.
Footnote 20:
See page 126.
Footnote 21:
“The wooden engine flies and whirls about,
Admired, with clamours, of the beardless rout:
They lash aloud; each other they provoke,
And lend their little souls at every stroke.”--DRYDEN.
Footnote 22:
Harl. lib. i. marked 6391.
Footnote 23:
Page 126.
Footnote 24:
Short on ‘Serson’s Horizontal Top.’ Phil. Trans. xlvii. 352.
------------------------------------------------------------------------
[Illustration: A boy playing on a swing between two trees.]
CHAPTER IX.
_Trap and Ball.--Gifts from the Vicar.--An Antiquarian History of
the Ball.--The See-saw.--The Mechanical Powers.--The Swing.--The
Doctrine of Oscillation.--Galileo’s Discovery.--The
Pendulum.--An interesting letter.--Mr. Seymour and the Vicar
visit Major Snapwell._
Mr. Seymour, having observed his children busily engaged at the game of
Trap and Ball, determined, as usual, to make it subservient to
scientific instruction. With this view he hastily sketched a diagram,
and proceeded with it to the scene of sport.
“Now, Tom, let me see how far you have profited by our late
conversation. I have some questions to ask you about the action of your
Trap and Ball,” said his father.
“I do not suppose there is much philosophy in the game,” observed Tom.
“Of that we shall judge presently.--Can you tell me the direction which
the ball takes after it flies from the spoon of the Trap, in
consequence of the blow of the bat upon the trigger?”
“It flies upwards, to be sure, and allows me to strike it with my bat,”
answered the boy.
“Very true; but at what angle?--I see you hesitate, look therefore at
the diagram I have prepared, and attend to my explanation of it.”
Mr. Seymour produced the sketch which we here present to our readers.
[Illustration: Sketch of Trap.]
“A B represent the spoon and trigger in their quiescent position. Upon
striking the end B with the bat, they are brought into the position
C D. The spoon will thus have described the small arc A C, when it will
be suddenly stopped by the end of the trigger D coming into contact
with the shoe. The motion of the ball, however, will not be arrested,
and it will consequently be projected forward out of the spoon.”
“Exactly,” exclaimed Louisa, “in the same manner as the shilling flew
off the wine glass, or a person on a galloping horse would be thrown
over the head by its suddenly stopping.”
“I thank you, Louisa; your memory, I perceive, has not suffered from
the drenching you received from the water-cart;[25]--but can you tell
me,” continued Mr. Seymour, “the direction which the ball will take
_after_ its release from the spoon?”
This was a step beyond Louisa’s knowledge, and her father, in order to
assist her, begged her to consider in what direction it was moving
_before_ it left the spoon.
“You have just told us,” said Tom, “that it described an arc, or
portion of a circle.”
“Very well,” said Mr. Seymour; “and did not the philosophy of your
sling teach you that, when a body revolving in a circle is suddenly
disengaged, it will fly off in a right line in the direction in which
it was moving at the instant of its release?--the ball therefore will
describe the tangent C E.”
“It is all clear enough to me now,” said Tom, evidently vexed that he
had overlooked a principle which had been so lately explained to him by
the action of his sling.
“I now see, too,” added Tom, “why the ball seldom flies off at the same
angle in every trap.”
“That,” said his father, “must of course depend upon the extent of the
arc described by the spoon, and which will of course vary in different
traps.”
“Before we conclude the subject, let me ask you whether there is not
some one point in the bat, at which you can most effectually strike the
ball?”
“To be sure,” answered Tom, “in the same way tha there is a point in my
hoop-stick at which I can give the strongest blow--and that point is
termed the _Centre_ of Percussion.”
“Enough,” said Mr. Seymour; “see, here comes the vicar.”
True to the hour appointed, did Mr. Twaddleton make his appearance,
just at the conclusion of the discussion above described; and, as he
approached the party, Louisa observed that he was carrying a canvass
bag in his hand.
“What have you there?” asked Mr. Seymour. “A sack of sugar-plums?”
“No, no; spheres of larger diameter. Here,” said the vicar, as he
opened his bag, “is a foot-ball for you, Tom; and here is a hand-ball
for you, Louisa.” He then presented each of the other children with a
similar present, exclaiming--
‘Nemo ex hoc numero mihi non donatus abibit.’[26]
as Virgil has it.”
“Perhaps,” said Mr. Seymour, “you will enhance the value of this
favour, by giving us an antiquarian history of the ball, which will be
very acceptable to us at this time, as we have just concluded a
philosophical enquiry upon that subject.”
To this request the vicar readily assented, and proceeded as follows:--
“The Greeks appear to have played with four kinds of ball: viz. the
_little ball_, the _great ball_, the _empty ball_ ( σφαιρα κενη ),
which was blown up with air, like our foot-ball, and the _leathern
ball_ ( κωρυκον ), which was suspended from the ceiling, and stuffed
with bran or sand, as those who tossed it were robust or delicate. The
Romans,” continued the vicar, “had also four kinds of _pilæ_, or balls.
The _follis_, a large ball made of leather and blown up with air, like
our foot-ball; the larger kinds of which were struck with the arm, the
smaller ones with the fist. Suetonius tells us that Augustus Cæsar
greatly delighted in the amusement; and in truth it was a glorious
sport, an exercise equally adapted for the young and old; or as Martial
has it,--
‘_Folle_ decet pueros ludere, _folle_ senes.’“[27]
“And yet,” said Mr. Seymour, “neither Horace nor Virgil played at it;
do not you remember the lines in the fifth satire?--
‘Lusum it Mæcenas, dormitum ego Virgiliusque;
Namque pilâ lippis inimicum et ludere crudis.’”[28]
“Many thanks, Mr. Seymour, many thanks for brushing up my recollection;
but I am a little doubtful about the game at which Mæcenas played at
Capua: I have, by-the-by, lately read[29] an account of a peculiar game
of ball for which the city of Sierra is celebrated, and it is supposed
to be that referred to by Horace--‘It is played in the foss, which has
a very high wall, and it is not unlike a tennis-court; the ball is very
large, and appears to be inflated with air; the arm is defended by a
wooden guard or shield; at certain periods of the game, one of the
players runs down a spring-board, and throwing the whole of his weight,
momentum, and strength upon the ball, as it is thrown towards him, he
strikes it to an astonishing distance.’ The second kind of ball,”
continued the vicar, “was termed _trigonalis_, which is conjectured to
have been nearly the same as our tennis-ball. It derived its name from
the position of the three persons who played with it; they were placed
in a triangle, and alternately caught and tossed the ball, and he who
first let it fall to the ground was the loser. The third kind of ball
was the _paganica_, as being much used in country villages. Some
authors state it to have been constructed of leather and stuffed with
feathers, while others conjecture it to have been a large kind of
_follis_. The fourth was the _harpastum_; a small ball, so called
because the gamesters endeavoured to snatch it from each other.”
“It seems,” observed Louisa, “to be a sport better adapted to boys than
girls.”
“In that supposition you are quite mistaken,” replied the vicar; “on
the contrary, the hand-ball would seem to have been originally a female
sport, for Homer has restricted the pastime to the princess and young
maidens of Corcyra; at least, he has not mentioned its ever having been
practised by the men.
‘O’er the green mead, the sporting _virgins_ play,
Their shining veils unbound; along the skies,
Toss’d and re-toss’d, the ball incessant flies.’”[30]
Mr. Seymour said that, as the vicar had satisfied them of the high
antiquity of the ball, he hoped he would now afford them some
information respecting its use in England.
“The game of hand-ball,” said the vicar, “called by the French
_palm-play_, because the exercise consisted originally in receiving the
ball, and driving it back again with the _palm of the hand_, was
formerly a favourite pastime among the youth of both sexes; and in many
parts of the kingdom it was customary for them to play at this game
during the Easter holidays for tansy cakes. In ancient times, the mayor
and aldermen of Newcastle used to go in state at the feasts of Easter
and Whitsuntide, to a little mall of the town, to witness this game. It
was originally played with the naked hand; then with a glove, which in
some instances was lined; afterwards, cords and catgut strings were
bound upon the hand to make the ball rebound more forcibly.”
“That custom,” observed Mr. Seymour, “doubtless, gave origin to the
_racket_.”
“It did,” replied the vicar; “and the places where this game was played
were called _tennis-courts_, and the game itself obtained the name of
_tennis_, from the French word _tenez_[31] (take it, hold it),
frequently used during the exercise. The pastime, I believe, was
introduced amongst our ancestors about the year 1222, the sixth year of
Henry III, by persons of superior rank and family, who erected courts
or oblong edifices for the performance of the exercise.”
“I long to hear something about foot-ball,” exclaimed Tom.
“That is a pastime,” said the vicar, “which was formerly in great vogue
in England, but of late years it has fallen into disrepute. It derives
its name, as you may suppose, from the circumstance of the ball being
driven with the foot, in preference to the hand. When a match is made,
two parties, equal in numbers, take the field, and stand between two
goals, which are placed at the distance of eighty or a hundred yards
from each other. The ball, which is commonly a blown bladder, cased
with leather, is delivered in the midst of the ground, and the object
of either party is to drive it through the goal of their opponents, by
which the game is won. The abilities of the performers are best
displayed in attacking and defending the goals, whence the pastime is
more frequently called a _goal_, than a _game_ at foot-ball. In this
attack and defence, the exercise becomes exceedingly violent; the
players kick each other’s shins without the least ceremony; and this
occasioned James I. to speak of foot-ball as ‘_meeter for laming than
making able the users thereof_.’”
“I believe,” said Mr. Seymour, “that the ancient game of _goff_ is
still much practised in Scotland.”
“It is,” replied the vicar. “In the reign of Edward III. the Latin name
_cambuca_, a crooked club, or staff, was applied to this pastime,
because it was played with such an instrument. The bat was also styled
a _bandy_, from its being bent; and hence the game itself is frequently
called _bandy-ball_.”
“And how is it played?” asked Tom.
“It is played on a smooth common, by driving forward two small hard
balls, with the _bandy_ I have just described, into very distant holes
in the ground, about a foot deep, and nine inches over: and the party
whose ball is driven into these holes with the fewest strokes, is the
victor.”
“But come,” said Mr. Seymour, “it is high time to think of our dinner;
the children must require some refreshment. I am not, my dear vicar,
one of those philosophers who believe that play was invented by the
Lydians[32] as a remedy against hunger; nor do I subscribe to the
opinion of the elder Scriblerus, that it was on such an account wisely
contrived by Nature, that children who have the keenest appetites
should, at the same time, be those who are most addicted to sport.”
“Whether you believe or not that the Lydians invented sports shall not
be a subject of contest between us,” said the reverend antiquary;
“but,” continued he, “one thing is quite certain, that the Lydian games
were at first called _Lydi_ by the Romans; and afterwards, by
corruption, _Ludi_; a presumption I must needs say in favour of the
Lydian claim; but enough of this: to what do you propose we should next
turn our attention? I doubt not you have some new sport for our
recreation as well as our instruction,” added the vicar.
“We will, if you please, attend the children to their _see-saw_, which
the gardener has lately constructed for them,” said Mr. Seymour.
The party accordingly walked to the grove, in which a plank had been
placed across a wooden post: and upon which Tom and John had been
riding for some time in the earlier part of the morning. The boys again
mounted their new hobby; and, after amusing themselves for some
minutes, Mr. Seymour desired them to stop, in order that Tom might
explain the principle upon which the _see-saw_ acted. Tom replied, that
he was not aware of any principle which could apply to riding on a
plank.
“Have I not often told you, my dear boy, that the principles of Natural
Philosophy may be brought to bear on the most trivial acts of life?
Listen, therefore, and you shall find that your present amusement teems
with instruction. You are already well acquainted with the nature and
operations of the centre of gravity; tell me, therefore, whereabouts it
lies in the plank upon which you are riding.”
“I should think,” replied Tom, “that in this instance, the centres of
gravity and magnitude must coincide, or be very nearly in the same
point.”
“The centre of gravity must, as you say, be very nearly in the middle
of the board; and if that be the case, you will allow that, supposing
those who ride upon it are of equal weight, the plank must be supported
in the centre to make the two arms equal; but you and John are of
unequal weight, so that you perceive the plank must be drawn a little
farther over the prop to make the arms unequal; and John, who is the
lightest, must be placed at the extremity of the largest arm. Thus
arranged, you will exactly balance each other; and as each of you, on
your descent, touches the ground with your feet, the reaction affords
you a spring, which destroys the equilibrium, and enables you to
oscillate in arcs about the centre of motion.”
[Illustration: Two children on a see-saw, with circles drawn around
them to show their motion.]
“Do we then describe the arcs of a circle as we ascend and descend?”
“Undoubtedly you must. Look at this diagram,” said Mr. Seymour, “and
you will see at once that the plank can only move round its centre of
motion; for how could you rise, or your brother fall, perpendicularly
in a straight line? You must, in rising, and he, in descending,
describe arcs of your respective circles. It is equally evident that
his velocity must be very superior to yours; for, if you could swing
quite round, you would each complete your respective circles in the
same time.”
“It would really appear so,” said Tom; “and I have myself observed,
that the lighter person has the better ride, as he moves both farther
and quicker, and I now understand the reason of it; it is because being
farther from the centre of motion, he describes a larger arc.”
“The greater velocity with which your little brother moves, renders his
momentum equal to yours. You have the most gravity, he the greatest
velocity; so that, upon the whole, your momenta are equal: for you, no
doubt, remember that momentum is weight multiplied into velocity.[33]
You have here then a striking instance of mechanical advantage gained
by opposing motion to matter, or velocity to weight; for I think you
will readily admit, that without the aid of the plank, your little
brother could never have raised you from the ground.”
“That is clear enough,” said Tom.
“The plank, then, thus arranged,” continued his father, “constitutes
what has been termed a _mechanical power_, to which the name of _lever_
has been given; it is not, however, my intention at present to enter
into the history of these powers, of which there are six distinct
kinds; the one presented to you, in the instance of the _see-saw_, is
perhaps the most simple, and not the least important of them.”
“It is very curious,” observed the vicar, “to reflect upon what a
simple, and apparently trifling fact, the powers of civilized man may
be said to depend. The single truth you have just announced, of making
velocity a compensation for weight, has supplied his weak arm with the
means of controlling the very elements.”(23)
“It is very true,” said Mr. Seymour, “and we might go so far as to say
that, had it been the will of the Almighty Creator of the universe to
have withheld from matter that property which we have been discussing,
man must have remained the most helpless and forlorn of his creatures.
I now propose,” added Mr. Seymour, “to accompany the children to their
swing; the present is a suitable opportunity for giving them some idea
of the doctrine of oscillation, or the theory of the pendulum.”
“Let us proceed, then, to the _Icarian Game_,” exclaimed the vicar.
As the party walked along, Mr. Twaddleton explained the meaning of the
above allusion, with which the reader will be hereafter made
acquainted. The children had commenced the sport, and Mr. Seymour
informed Tom and Louisa, who were attentively watching the motions of
the swing, that its vibrations, like those of the pendulum of a clock,
were produced by its effort to fall, from the force of gravity, and its
power of ascending through an arc similar and opposite to that through
which it has descended, from the momentum acquired during its descent.
“Like the bandilor, I suppose,” said Louisa.
“Exactly, my dear, that is a very good comparison; for as the bandilor,
having descended along the string by its gravity, acquires such a
momentum as to enable it to ascend the same string, and thus, as it
were, to wind itself up; so does the pendulum or swing, during its
descent, acquire a force that carries it up in an opposite arc to an
equal height as that from which it had fallen. But tell me, Tom,
whether you have not discovered that the motion of your new swing
differs from that which you experienced in your former one?”
“The ropes of our present swing are so much longer than those which we
formerly used, that the motion is much pleasanter.”
“Is that all?” said Mr. Seymour. “Have you not observed that you also
swing much slower?”
“I have certainly noticed that,” said Tom.
“It is a law which I am desirous of impressing upon your memory, that
the shorter the pendulum, or swing, the quicker are its motions, and
_vice versâ_; indeed, there is an established proportion between the
velocity and the length, which I shall, hereafter, endeavour to explain
to you. Galileo, the celebrated philosopher, and mathematician to the
Duke of Florence, accordingly proposed a method of ascertaining the
height of the arched ceiling of a church by the vibrations of a lamp
suspended from it. The solution of the problem was founded on the law
to which I have just alluded, viz. that _the squares of the times of
the vibrations are as the lengths_; so that a pendulous body, four
times the length of another, performs vibrations which last twice as
long. Now it is known that, in the latitude of London, a pendulum, if
39 inches and two tenths in length, will vibrate seconds, or make 60
swings in a minute; by observing, therefore, how much the pendulous
body deviates from this standard, we may, by the application of the
above rule, find its length; if the distance from the bottom of the
lamp to the pavement be then measured, which may be done by means of a
stick, and added to the former result, the sum will give the height of
the arch above the pavement: but I will show you the experiment the
next time we go into Overton church; the vicar can tell us the exact
height of the roof, and I will try how nearly I can approach the truth,
by observing with a stop-watch how many seconds one vibration of the
chandelier continues.”
“But, papa, why surely the duration of its vibration must depend upon
the force which you may happen to give to the chandelier?”
“Not in the least; and this brings us at once to the consideration of
the most curious and important fact in the history of the pendulum, and
for a knowledge of which we are also indebted to Galileo.[34] It is
termed _isochronous_[35] property, or that by which all its vibrations,
whether great or small, are performed in exactly the same period of
time; but that you may be better able to comprehend this subject,
attend to the diagram which I have prepared for your instruction.
Suppose that the swing or pendulum A B be raised to C, it will, in
effect, be raised the perpendicular height E C, and in falling will
describe the arc C B; and, in the point B, it will have that velocity
which is acquired by descending through C B, or by a body falling
freely through the perpendicular C E. This velocity will be sufficient
to cause it to ascend through an equal arc B D, to the same height from
whence it fell at C; and since the times of ascent and descent are
equal, it will describe both these arcs in exactly the same space of
time. Having lost all its motion at D, it will again begin to descend
by its own gravity; and in the lowest point B it will acquire the same
velocity as before, which will cause it to reascend to C; and thus, by
ascending and descending, it will perform continual vibrations in the
circumference C B D; and, were it not for the resistance of the air,
and the friction at the centre of motion A, the vibrations would never
cease: but from these obstructions, though small, it happens, that the
velocity of the mass of matter at B is a little diminished in every
vibration; and consequently it does not return precisely to the same
points C or D, but the arcs described continually become shorter and
shorter, till at length they grow insensible; and yet the very same
time is required for the performance of the shorter as the longer arcs;
for, although in the one case the body passes over less space, still
its velocity is proportionally decreased. You perceive, then, that in
an attempt to ascertain the height of a ceiling by the vibrations of a
chandelier, the extent of its swing cannot alter the time which may be
required for its completion. And, if you will place your little brother
in the swing, you will perceive that he will return to your hand in
nearly the same space of time, whether he describes a large or small
arc; although this experiment must be considered as extremely rude,
since there are many disturbing causes for which the theory cannot
possibly make any allowance. I must, moreover, warn you that where the
arc described is very considerable, the difference in the time will be
greater; for, in order to ensure this property of vibrating through
unequal arcs in equal times, it is necessary that the path of the body
should describe a peculiar curve, called a cycloid(24), and not the
segment of a circle; at present, however, it is not possible for us to
enter into this difficult branch of science, although I trust that at
some future period I shall be justified in an attempt to explain it.”
[Illustration: Drawing of a pendulum and its movements.]
Mr. Seymour having concluded his lecture, was about to return to the
Lodge, when Mrs. Seymour approached the party, carrying in her hands a
letter, which the smile on her countenance announced to contain
agreeable intelligence.
“I have just received,” said Mrs. Seymour, “a letter from Miss Villers,
whom you must all remember as a most delightful person. I am informed
that she is about to be married to the nephew of a gentleman who is at
present in our neighbourhood in search of a country residence.”
“Does she mention the gentleman’s name?” inquired the vicar.
“Mr. Henry Beacham,” said Mrs. Seymour.
“The nephew of Major Snapwell, I declare,” exclaimed the delighted
vicar.
The whole party participated in the pleasure which their excellent
friend expressed at this discovery, and Mr. Seymour immediately
accompanied Mr. Twaddleton to Ivy Lodge, to congratulate the major, and
to make such arrangements as might expedite the purchase of Osterley
Park, and the consequent introduction of a family into the
neighbourhood of Overton, from whose society the Seymours anticipated
the highest satisfaction.
At the same time Mrs. Seymour hastened to dispatch a letter to Miss
Villers, in order to solicit her immediate presence at Overton Lodge.
-----
Footnote 25:
See page 65.
Footnote 26:
“Not one amongst you shall depart without a gift from me.” _Æn_. v.
305.
Footnote 27:
Lib. xiv. epig. 43.
Footnote 28:
“Mæcenas goes to tennis, hurtful game
To a weak stomach, and to tender eyes,
So down to sleep with Virgil, Horace lies.”--FRANCIS.
Footnote 29:
“Two Hundred and Nine Days,” or “The Journal of a Traveller on the
Continent,” by Jefferson Hogg: London, 1827.
Footnote 30:
Pope’s Odyssey, lib. v.
Footnote 31:
This etymology has been disputed, and it has been said that the
holding or keeping possession of the ball is no part of the game;
for, during the play, the ball is in continual motion, or passing
from one to another. Others seek the etymology of the name, and the
origin of the game, in a place in France called Tennois; or, by a
change of one letter, Sennois, in the district of Champagne, where
balls were first made, and the game, as it is said, first introduced.
Footnote 32:
Herodotus speaks of the inhabitants of Lydia having successfully had
recourse to gaming as a partial substitute for food, during a famine
of many years’ continuance.
Footnote 33:
See page 61.
Footnote 34:
This discovery was published at Paris, in a treatise called “_L’Usage
du Cadran, ou de l’Horloge Physique Universelle_,” in the year 1639;
from which may be dated the invention of the pendulum.
Footnote 35:
Compounded of the Greek words ισος equal, and χϱονος time.
------------------------------------------------------------------------
[Illustration: Three people looking at a diagram drawn on the ground.]
CHAPTER X.
_Marbles.--Antiquity of the game.--Method of manufacturing
them.--Ring-taw.--Mr. Seymour, the Vicar, and Tom, enter the
lists. The defeat of the two former combatants; the triumph of
the latter.--A philosophical explanation of the several
movements.--The subject of Reflected Motion illustrated.--The
Vicar’s apology, of which many grave personages will approve._
In our last chapter we left Mr. Seymour and his reverend friend on
their way to Ivy Cottage; it is only necessary to state that the major
received them with that satisfaction and gratitude which the nature of
their visit could not fail to produce. Plans were proposed, and
arrangements concluded for the furtherance of the object we have
announced; in short, in the brief space of an hour, the major had
determined the course of his future life, and had framed schemes of
happiness, and visions of domestic peace, which he impatiently sought
to realize. The vicar was detained by the major, but Mr. Seymour
quitted Ivy Lodge and returned to his family. He found the children
engaged in playing at marbles. Tom was displaying to his sisters many
instances of his adroitness and skill in shooting at and hitting
marbles.
“Why, Tom!” exclaimed Mr. Seymour, “how came you possessed of such a
multitude of marbles?”
“By luck; good luck, papa; I won them all before the holidays; and I
can assure you that my school-fellows acknowledge me as one of the best
players at _ring-taw_ in the school.”
“Justly, then, has your merit been rewarded,” said the father. “Have
you not read of the skilful Roman, who could blow peas through a quill,
and deposit them with such nicety on the point of a pin, placed at some
distance, as rarely to miss his aim?”
“And what was his reward?” asked Tom.
“A bushel of peas, my boy, which the emperor commanded to be presented
to him. But do not misunderstand me, far be it from my wish to
disparage your skill; whatever we undertake, we should endeavour to
accomplish; I am, therefore, well pleased to find that you can play at
marbles with so much success.”
“I wonder who invented marbles?” said Tom.
“That question, my dear, must be addressed to Mr. Twaddleton, who, I
have no doubt, will immediately answer it.”
Scarcely had these words been spoken, when the vicar appeared on the
lawn. Mr. Seymour informed him of the subject of their conversation,
and added, that he had just told the children he was sure he would
readily answer their question.
“Not so readily as you may imagine,” replied the vicar; “but I will
tell you all I know upon the subject. It appears to be a very ancient
game; for it is stated by Suetonius, that Augustus, when a youth, spent
many hours in the day in playing with little Moorish boys ‘_cum
nucibus_,’ that is, _with nuts_, which appear to have been then used in
the very way in which you now play with your marbles. In later times,
round stones, picked out of gravel, were introduced for this purpose.
The marbles which you now hold in your hand are substitutes of still
more modern invention. The best of them are imported from Holland,
where, as I have been informed, they are manufactured by grinding
fragments of alabaster and of other stones, in an iron mill of a
peculiar construction, in which there are several partitions furnished
with rasps, which turn with great velocity, by means of a stream of
water; and thus, having rounded the stones, project them out of
different holes for which their size may adapt them. Thus manufactured,
they are brought down the Rhine, and from thence dispersed throughout
Europe; immense quantities are also exported to India and China. There
are, however, as you well know, inferior kinds, which are of home
manufacture, and consist of potter’s clay covered with a glaze, and
burnt in a furnace.”
“I have often wondered what is the meaning of the words _taw_ and
_ally_,” observed Tom.
“Why, your _taw_ is a brown marble, and your _ally_, if I remember
rightly, a very white one; is it not so?” asked the vicar.
“To be sure,” said Tom.
“Very well, then,” said the vicar, “the words are clearly abbreviations
of _tawny_ and _alabaster_.”
“Now then,” said Mr. Seymour, “for a game; what is it to be, Tom?”
“_Ring-taw_ for ever!” cried Tom; “it is the only game of marbles
worthy of being played.”
“It is really so long since I left school,” observed his father, “that
I must beg you to refresh my memory, and give me some instructions
about this favourite game of yours.”
“I will tell you all about it. We must first draw a circle, on which
each player is to put a certain number of marbles to be previously
agreed upon; we then make a mark at some distance, which is called the
_offing_, and from which we are to shoot at the marbles in the ring.”
“That is all very intelligible,” observed his father; “and I suppose
the object of the player is to shoot a marble out of the ring, which
not only gives him that marble, but entitles him to shoot again at
another, and so on, until he misses, or all the marbles are won.”
“That is right, papa.”
“And a good marksman,” observed the vicar, “who has the first shot, may
easily win the game, before any other player can gain the opportunity
of shooting at a single marble.”
“I see that clearly,” said Mr. Seymour; “he may strike out a marble
from the circle, and then shoot at another, and in this manner traverse
the whole ring; I therefore conclude, that good players will always
demand a large ring, or else there would not be much chance for any
one, except for him who played first.”
“That is the game; but I must tell you,” said Tom, “that if the player
should leave his own marble in the ring, he is at once put out; and
should it be within a certain distance on the outside, an adversary may
shoot at it, and by hitting it, put him also out of the game.”
“I believe that I am now a perfect master of the subject,” said Mr.
Seymour; “what say you, vicar?”
“I understand it; and it appears to me to be capable of some scientific
calculation; but the practical results must, of course, differ very
widely from the theory, for the unevenness of the ground, and the
inaccurate construction of the marble, are circumstances which never
can be duly estimated.”
“Certainly not,” replied Mr. Seymour; “these difficulties even exist at
the game of billiards(25), where the table is smooth and perfectly
horizontal: but we do not require perfect accuracy, an approximation to
it will be sufficient for the purposes of illustration; we will,
therefore, if you please, proceed at once to the game, and I will
endeavour to point out to Tom the nature and direction of the several
forces by which each marble will be influenced.”
Tom, accordingly, like the son of Cornelius Scriblerus, converted his
legs into a pair of compasses, and described, with the toe of his shoe,
the necessary circle upon the ground. Each party, by agreement, placed
two marbles upon the ring, and it fell to the lot of the vicar to open
the campaign. Mr. Twaddleton then advanced, and with the assumed air of
a true knight-errant, approached the ring, exclaiming with a loud
voice, and with a gesture of inexpressible drollery, “I demand gracious
leave that I may be delivered of my vow, and forthwith combat in the
lists;” so saying, he unfurled his red banner, and sounded a trumpet;
or in more humble phraseology, he extracted his hand-kerchief from his
pocket, and applying it to his nasal organs, produced a loud and
thrilling blast, which frightened every sparrow from its resting-place.
After this preliminary ceremonial, he marshalled his limbs into the
most appropriate attitude, and thrusting one hand behind the exuberant
tail of his coat, he, with the other, shot forth his missile at the
largest marble opposite to him. His _taw_ faithfully delivered its
errand, and inflicted such a blow upon the paunch of his antagonist,
that although nearly twice the size of its assailant, like a true
bully, it skulked off, and retreated several feet beyond the lists;
but, alas! the little marble of the vicar, unlucky wight! was so
stunned by the operation, that it staggered, and reeled backwards into
the ring, and thus, according to the established law of the field,
completed by one act the total defeat of its luckless commander.
“Your marble is left in the ring!” exclaimed Tom, with a shout of
triumph.
“I see how it happened,” said Mr. Seymour; “the vicar struck the marble
plump, or ‘played a full ball,’ as we say at billiards, and the result
easily admits of explanation. You already know that a marble possesses
elasticity; when, therefore, the one in the ring was struck, it went
off with a velocity equal to that with which the striking marble
approached it, while the latter, in return, received a blow equal to
that it gave, which destroyed its motion. When we go back into the
library, I will exhibit a very pretty experiment in farther elucidation
of this philosophical truth.”(26)
It was now Mr. Seymour’s turn to enter the lists. He carefully applied
his knuckles to the ground, and taking aim at a little marble which he
had selected as his victim, gallantly shot the missile from his thumb
and finger; but, alas! alas! the goddess, whatever may be her name, who
presides over this species of tournay, doubtless saw the impending fate
of her favourite, and, after the example of Venus, who turned aside the
weapon from Æneas, assumed the shape of a small pebble, and thus
arrested the fatal course of the marble, and gave it a new direction,
which sent it curveting through the ring, without committing one single
act of devastation.
“Bravo! bravo!” exclaimed Tom, “it is now my turn.”
The boy, according to the usage of the field, might at once have won
the game by striking his father’s marble; but he was too magnanimous to
take such an advantage, and too eager to display his own skill, to cut
the game short by a manœuvre: he had determined to win his laurels by
hard fighting and generalship. He accordingly proceeded to strike a
ring marble; in effecting which he had, like the vicar, challenged a
_gigantic knight_ as his antagonist; but, instead of striking it
_plump_, he struck its upper quarter, so that it was rolled out of the
ring, while the striking marble, imparting only a portion of its
momentum, continued to move forward after the impact. This course was
greeted with the acclamations of Mr. Seymour and the vicar, the latter
of whom declared it to have been “nobly run,” and gallantly
accomplished; and extracting a sixpence from his waistcoat pocket,
exclaimed, after the manner of chivalry, “_Largesse, largesse_, glory
to the sons of the brave! glory to the invincible knight of the taw!”
The boy had not only struck the marble out of the ring, but he had, at
the same time, contrived to place his own marble in the most favourable
position for his future operations; and, indeed, it may be here
observed, that in this consists the art of playing the game. It is
almost unnecessary to add that Tom won every marble in succession.
Mr. Seymour then proceeded to explain the laws of impact, by which the
movement of each marble was directed. He observed, that the subject
embraced two propositions, viz. the direction of the _object_ marble
after having been struck, and that of the _striking_ marble after the
stroke. He said that, if a straight line were drawn between the centres
of the striking and object marbles, it would necessarily pass through
their point of contact, and, if continued, would represent the path of
the latter after the blow. In order to find the direction of the
_striking_ marble after the shock, he told him that he must imagine a
tangent to the path of the _object_ ball drawn from its centre, and
then a line parallel to it, from the centre of the striking marble; the
latter of which would be the required path.
Mr. Seymour now inquired whether there was any other game of marbles at
which they could amuse themselves.
“The game which we call ‘_lagging out_,’” replied the boy, “is amusing
enough. It consists in striking your marble against the wall, and
making it rebound, so as to hit any other marble that is placed at a
certain distance from it, or to come within a span of it.”
“I understand,” said his father, “and, like _ring-taw_, it may be made
subservient to our purpose of illustrating the doctrine of forces;
although I think that the principle of _reflected motion_ may be more
readily explained by the rebounding ball.”
Mr. Seymour here took the elastic ball, and threw it obliquely against
the wall, from which it rebounded in an opposite and equally oblique
direction. He then sketched the annexed figure, and proceeded as
follows:--“When I threw the ball against the wall B, in the direction
A B, having struck it, it glanced off, making an angle, in its passage
back again, equal to that which it made in its approach to the wall. If
I draw the perpendicular B D, this fact will be rendered more apparent,
and you will perceive that the angle A B D is equal to the angle C B D:
the former is termed the _angle of incidence_, the latter the _angle of
reflection_; and these angles, remember, are always equal, provided the
ball under experiment be perfectly elastic.”
[Illustration: Diagram showing the physics of rebounding.]
“Do you mean to say,” asked Tom, “that the more obliquely I throw the
ball against the wall, the more obliquely it will rebound?”
“Exactly; that is my meaning: and see whether you cannot explain the
fact, for it depends on the composition and resolution of the forces, a
subject which I should hope you thoroughly understand.”
Tom pondered for some time over the drawing, and at length observed,
that there was one difficulty which he could not immediately surmount.
“State your difficulty,” said Mr. Seymour.
He proceeded to observe, that the force acting in the direction A B
would certainly be resolved into two others, viz. one in the direction
F B, and another in that of D B; “because,” continued he, “these lines
are the adjacent sides of the parallelogram, of which A B is the
diagonal; and I well know that whenever a force strikes obliquely, it
is thus resolved.”
“That is all very well explained,” replied his father; “pray proceed.”
“Now comes the difficulty,” continued Tom; “for the force D B will of
course be destroyed by the wall, and that represented by F B, which is
the only one that can remain, would carry the ball to E.”
“It certainly would do so,” answered his father, “if the ball were
perfectly devoid of elasticity; but remember that, in consequence of
this property, the force D B will be exchanged for one in an opposite
direction, B D.”
“I had entirely overlooked the elasticity,” said Tom; “I now see my way
clearly, for in that case there must be two forces acting in the
directions B D, B E, which will, of course, drive the ball down the
diagonal B C.”
“Your demonstration is perfectly correct, my boy; and I think you will
now admit that I could not have adduced a more beautiful instance of
the composition and resolution of forces; for, in the first place, you
resolve the diagonal force into two others, and then you recompound
these again to produce another diagonal one.”
“But I think you told us that the angles of incidence and reflection
were only equal when the rebounding body was perfectly elastic.”
[Illustration: Diagram showing more physics of rebounding.]
“Clearly so; the force D B must be exchanged for an equal one B D, or
else the angle A B D cannot be equal to the angle D B C; but I will
render this fact still farther intelligible by another diagram. Let B,
as in the former case, represent the wall, upon which the imperfectly
elastic body impinges in the direction A B.--The force will of course
be resolved into two others, viz. into D B and F B; the force D B,
however, instead of being replaced by the opposite one B D, will now be
represented by the shorter line B G; or that of B H or B I, according
to the degree of elasticity. If we, therefore, complete the
parallelogram, B C, B K, or B M will be the diagonal path of the body;
making, as you perceive, the _angle of reflection_ D B C, greater than
that of _incidence_ A B D; and where the body is perfectly inelastic,
the force D B will be wholly destroyed, and, the force B E alone
surviving, the body will be carried along the line B E. I have now,”
continued Mr. Seymour, “explained to you the principal laws which
govern those forces by which your ball or marbles are actuated. It is
true that in practice you cannot expect the results should accurately
coincide with the theory, because, in the first place, you cannot
obtain marbles that are of equal density and elasticity, and of true
figure; and, in the next, there will be obstacles against which it is
impossible to guard. The spinning of the marble will also have a
material influence on its motion, as we have already discovered. In the
game of billiards, where every obstacle is removed, as far as art can
assist, the theory and practice are often strangely discordant. But we
have dwelt sufficiently upon the subject; we will, therefore, return to
the library, where I intend to exhibit an experiment in farther
elucidation of the subject of collision.”
The party accordingly proceeded on their return.
“I hope,” said Mr. Seymour, addressing himself to Mr. Twaddleton, who
was walking a few paces before him, “that the maiden ladies have not
espied their vicar at a game of marbles; if they should, what a
chuckling would there be at their next tea-party!”
“A fig for the spinsters!” exclaimed the vicar, as he hastily turned
round, and arrested the progress of the party by his gesture. “You
really speak, Mr. Seymour, as though it were derogatory to my character
to descend from the more austere pursuits to the simple but innocent
amusements of youth. Let me remind you, sir, that the Persian
ambassadors found Agesilaus, the Lacedæmonian monarch, riding on a
stick.”
“True,” replied Mr. Seymour; “and the ambassadors found Henry the
Fourth playing on the carpet with his children; and it is said, that
Domitian, after he had possessed himself of the Roman empire, amused
himself by catching flies; but these were kings: now I admit that
philosophers are monarchs, but monarchs are not always philosophers;
you must, therefore, produce some less objectionable authority, if you
stand in need of such a sanction. Let me see whether I cannot assist
you; there was Socrates, if tradition speaks truly, who was partial to
the recreation of riding on a wooden horse, for which, as Valerius
Maximus tells us, his pupil Alcibiades laughed at him.”
“I care not who laughs at me,” exclaimed the vicar; “I enjoy the
amusements of youth, and agree with Dr. Paley, in regarding the
pleasure which they are made to afford, as a striking instance of the
beneficence of the Deity; and should you so far relax as to put your
plan into execution, of writing a work upon juvenile sports, I hope you
will call upon me to compose a eulogy, by way of preface.”
“I shall not forget your offer, depend upon it.”
“Did not Archytas,” resumed the vicar,
“‘He who would scan the earth, and ocean’s bound,
And tell the countless sands that strew the shore,’
as Horace says, invent the children’s rattle?--Toys, my dear sir, have
served to unbend the wise, to occupy the idle, to exercise the
sedentary, to moralize the dissipated,”--
“And,” interrupted Mr. Seymour, “to instruct the ignorant.”
“I will also convince you,” continued the vicar, “that the tournaments
were indebted for their origin to the Troy game (_ludus Trojæ_), first
introduced into Italy by young Ascanius.”
The foregoing episode having been concluded, the party proceeded,
without any farther interruption, to the Lodge. On their arrival, Mr.
Seymour produced a piece of apparatus, for the purpose of exhibiting
the experiment he had promised, in illustration of the doctrine of the
Collision of Elastic Bodies.
[Illustration: Two balls, labeled A and B, hanging by strings from a
rod and bouncing against each other.]
“Here are two ivory balls,” said he, “suspended by threads; I shall
draw one of them, A, a little on one side; now I let it go, it strikes,
you see, against the other ball, B, and drives it off to a distance
equal to that through which the first ball fell; but the motion of A is
stopped, because, when it struck B, it received in return a blow equal
to that it gave, and its motion was consequently destroyed. To extend
the experiment, here are six ivory balls hanging in a row; I will draw
the first out of the perpendicular, and let it fall against the second;
see! see! none of the balls appear to move except the last, which you
perceive flies off as far as the first ball fell. I should like to hear
you explain this.”
[Illustration: Six balls hanging by strings from a rod and bouncing
against each other, but with only the two balls on the ends moving.]
Tom observed, that when the first ball struck the second, it received a
blow, in return, which destroyed its motion; and that the second ball,
although it did not appear to move, must have struck against the third,
the reaction of which set it at rest; that the action of the third ball
must have been destroyed by the reaction of the fourth, and so on,
until motion was communicated to the last ball, which not being reacted
upon flew off.
Mr. Seymour commended Tom for his explanation; but he begged him to
understand that such an effect only occurred when the balls were
elastic; and he proceeded to exhibit the difference between elastic and
inelastic bodies by another experiment. “When you raise one of these
inelastic balls, made of clay, out of the perpendicular, and let it
fall against the other, E, the action and reaction not being augmented
by the force of elasticity, are insufficient to destroy the motion of
the former; only part of the motion D will, therefore, be communicated
to E, and the two balls will move together to _d e_, which are less
distant from the vertical line than the ball D was before it fell.”
[Illustration: Two suspended, inelastic balls, labeled D and E ,
showing positions after D collides with E]
Before we close this chapter, we cannot resist the pleasure of
informing our readers that Major Snapwell, in company with his legal
adviser, had quitted Overton, for the purpose of making such
preliminary arrangements as the purchase of an estate must necessarily
require. It is not our intention to accompany them; nor shall we travel
over the plains of parchment, nor wade through the rivers of ink, which
separate the confines of verbal agreement and legal possession; but
claiming the prerogative of authors, we shall dip our wing in the cup
of inspiration, and by a single flourish of our feathered talisman, at
once put the worthy Major in the undisturbed possession of his newly
purchased mansion, and instal him in one of Daw’s most comfortable
elbow-chairs, surrounded by all the luxuries of polished life.
------------------------------------------------------------------------
[Illustration: Two boys causing havoc by upsetting a washerwoman.]
CHAPTER XI.
_Mr. Seymour and his family visit the Major at Osterly Park.--A
controversy between the Vicar and the Major.--The
sucker.--Cohesive attraction.--Pressure of the
atmosphere.--Meaning of the term suction.--Certain animals
attach themselves to rocks by a contrivance analogous to the
sucker.--The limpet.--The Walrus.--Locomotive organs of the
house-fly.--A terrible accident.--A scene in the village, in
which Dr. Doseall figures as a principal performer.--The Vicar’s
sensible remonstrance.--The density of the atmosphere at
different altitudes.--The pop-gun.--The air-gun.--An antiquarian
discussion, in which the Vicar and Major Snapwell greatly
distinguish themselves._
In the course of the ensuing week Mr. and Mrs. Seymour proceeded to
offer their congratulations to the new proprietor of Osterley Park. On
being ushered into the library, they were not a little surprised and
startled by the loud voice of the major, who, addressing Mr.
Twaddleton, exclaimed,
“Never will I again suspect the antiquity of your rarities, nor
question the rarity of your antiquities.”
“Mr. and Mrs. Seymour,” said the major, “welcome to Osterley Park. You
find me, as usual, engaged with our friend in a learned controversy,
and I begin to fear that my warmth may have offended him.”
“Offended me!” exclaimed the vicar, “oh no. No, indeed, my dear Major
Snapwell; a difference of opinion on an antiquarian subject may excite
my regret, and in some cases, as in the present instance, awaken my
pity; but it cannot offend me; it can never occasion any feeling like
anger: that would be to visit the folly of others upon myself.”
“What is the subject of your difference, gentlemen?” asked Mr. Seymour.
“The evidences of druidical rites, as deducible from certain cavities
to be found in granitic rocks, and which have received the appellation
of _rock basins_,” replied the major.
“And of which,” exclaimed Mr. Twaddleton, “I have a most unquestionable
specimen, collected by no less a geologist than the curator of the
cabinet at Penzance, from that ancient metropolis of the druids,
_Carn-bre hill_.”
“I admit,” said the major, “that I never before saw so perfect a
specimen; it is as spheroidal internally, as if it had been actually
shaped by a turning-lathe.”
“And yet, in spite of such evidence,” replied the vicar, “you question
its sacred origin, and deny its ever having been used as a pool of
lustration.”
Mr. Seymour here interposed. “Upon a subject of purely historical
difficulty, I might feel diffident in offering myself as an umpire
between such learned antiquaries; but, as the origin of ‘rock basins’
involves a geological question, I will venture to deliver an opinion.
Depend upon it, vicar, that you are maintaining a position that cannot
be defended; these uncouth cavities, together with all the fancied
statuary of Borlase(27), never been shaped by any chisel but the tooth
of time, nor have any artists but the elements been engaged in their
formation.”
“What say you to that, vicar?” triumphantly exclaimed the major.
“Oh, impiety, impiety!” cried the vicar;--
“‘Hostis habet muros, ruit alto a culmine Troja,’
as Maro has it. That such glorious monuments, which have so long braved
the tempests, should fall under the hammer of these Philistines!
Geology, Mr. Seymour, is infidelity in masquerade; remember the mites
in the Cheshire cheese, Mr. Seymour, ‘consider their ways and be wise.’”
“Philistines as we are, in your opinion,” replied his opponent, “our
forges have served to sharpen your weapons against the attacks of
infidelity.”
“Come, come, gentlemen,” said Mr. Seymour, “the continuance of this
discussion can neither amuse nor instruct us. I have, however, some
intelligence to communicate which will soothe every feeling of
irritation. We have received a letter from Isabella Villers, in answer
to an invitation to Overton, and she graciously accepts it, and
proposes being with us on Wednesday next.”
The major was delighted, and conversed upon various points connected
with the intended union of his nephew with that lady, which we do not
think it necessary to relate in this place. The vicar and major shook
hands, and it was proposed that they should dine at Overton Lodge the
following day, and, as a specific overture, that the major should visit
the vicarage in his way, and again inspect some of the disputed
antiquities of the reverend collector.
The following morning was occupied with the consideration of those
different toys which are indebted for their operation to the pressure
of the atmosphere.
“Tom,” said Mr. Seymour, “fetch hither your leathern sucker.”
“John is, at this moment, amusing himself in the garden with the one
which I brought with me from school,” replied Tom.
“Then you shall construct another for yourself. Here is leather and
string.”
“This leather is too stiff; but I may, perhaps, make it answer the
purpose by first soaking it.”
Having allowed it to remain in water for a short time, the leather
became sufficiently pliable for his purpose; he therefore cut it into a
circular shape, and affixed a string through its centre. The juvenile
party now hastened to the lawn, and having once again dipped his
newly-constructed sucker into the water, the ingenious boy placed it
upon a stone, pressed down the leather with his foot, and succeeded in
making it raise the weight.
“Well done, my boy! Now, then, explain the reason of the leather’s
adhesion to the surface, and of its being thus capable of retaining its
hold, notwithstanding the gravity of the stone.”
“In the first place,” answered Tom, “the edges of the wet leather, from
being closely pressed, stuck with sufficient firmness to the smooth
surface of the stone, to resist the force of the string as I pulled it
upwards; the consequence was, that a hollow was formed in the middle
part of the leather; and, as that hollow place cannot contain any air,
it is called a _vacuum_.”
“Very well,” replied his father, “so far you are right; but you have
not informed me in what manner a _vacuum_ acts in preventing the stone
from quitting the leather.”
“It makes it adhere to it by some kind of _suction_, but I confess that
I do not exactly understand the subject.”
“Then let us proceed cautiously and deliberately in the explanation. In
the first place, you have said, and said correctly, that the edges of
the leather adhere to the stone; but what is the nature of the power to
which this adhesion is to be referred? I perceive you are puzzled by
the question: attend, then, to my explanation: you must know that there
exists a tendency in all bodies to adhere together, provided the
contact of their surfaces be sufficiently perfect; this property is
termed _cohesion_, or cohesive attraction, from the Latin word
_cohæreo_, which I need not inform you signifies to _stick together_.
The dry leather will not adhere to a smooth surface, because, in that
case, the contact cannot be rendered sufficiently perfect; but, when
saturated with water, the interstices of the leather are filled with
that fluid, and the inequalities of the surface, which must always
prevent close contact, are removed. If two bodies, when placed
together, be not sufficiently smooth, or polished, it will be vain to
make any attempt to produce their cohesion; since the particles will,
in such a state, touch each other only in a few points; it is for this
reason that carpenters, when they intend to glue pieces of wood
together, plane the surfaces perfectly smooth, before they apply the
glue.”
Tom here acknowledged that he had not before understood the reason of
the leather’s adhesion to the stone.
“Having, then, settled this point to your satisfaction,” continued Mr.
Seymour, “let us proceed. Your idea of a _vacuum_ being formed in the
hollow part of the leather is perfectly correct: for, as you draw up
the central part by the string, the hollow thus produced must
necessarily be a _vacuum_, since the air cannot pass through the
leather to supply it; in this state, therefore, the atmosphere presses
upon the exterior of the leather, and like any other weight prevents
its rising from the stone.”
Fanny and Louisa here expressed some surprise on hearing of the weight
of the atmosphere; the former observed, that she did not feel any
pressure from it. Their father explained the reason of their not being
conscious of the weight, by informing them that their bodies contained
air, which, by its elasticity, counteracted the pressure from without;
but that, if it were possible to remove all the air which the body
contained, the pressure of the atmosphere would not be counteracted;
and the consequence would be, that we should be flattened like a
pancake by its weight, which had been ascertained by experiment to be
equal to fifteen pounds upon every square inch of surface, or, as much
as forty thousand pounds upon the body of a man of ordinary size.
“Until your explanation,” said Tom, “I really believed that the leather
adhered to the stone by some kind of _suction_, just as the back of my
hand adheres to my lips, whenever I place it to my mouth, and draw in
my breath.”
Mr. Seymour here expressed a doubt whether his son was even yet a
perfect master of the subject: he told him that there was no such
operation in nature as _suction_; that it was merely a popular term to
denote the action of the air upon a vacuum. “Your hand,” said he,
“adheres to your mouth, in consequence of your forming a vacuum within
it, by forcibly drawing in your breath, and the resistance which is
opposed to its removal arises entirely from the pressure of the
atmosphere upon it. Many are the effects which may be explained upon a
similar principle. I dare say you well remember the astonishment which
you expressed at the force with which the limpets attached themselves
to the rocks.”
“O yes, papa,” exclaimed Louisa, “I well remember, when we walked on
the sea-shore, that, on first touching the limpets, they appeared loose
and moveable, but before I had time to remove them, they fastened
themselves as firmly as though they had been a part of the rock upon
which they were fixed; how could that happen?”
Mr. Seymour replied, that these sea-insects possessed the power of
converting their whole bodies into _suckers_; and he informed them,
that many other animals were endowed with a similar faculty. He
instanced the claws of the polypus, which are furnished with many such
suckers, by means of which the animal is enabled to hold to whatever it
attaches itself, with very considerable force.
“Have you never observed,” asked Mr. Seymour, “the security and ease
with which flies frequently walk upon a smooth wall, or a pane of
glass, or even along the ceiling, with their bodies downward?”
“To be sure,” replied Tom; “but are not their legs provided with some
sticky matter, which enables them to preserve themselves from falling?”
“That is a popular error, my dear; the fact is, that their feet are
provided with little cups, or suckers, which they alternately exhaust
and fill with air; by which means they are enabled to walk in every
position, over the most slippery surfaces.(28) In like manner, the
walrus, or seal, a painting of which you may remember to have seen in
the Panorama of Spitzbergen, is capable of climbing the masses of
slippery ice with perfect security.”
At this moment, Tom’s stone fell from the sucker. Louisa enquired how
it could have happened.
“The circumstance is to be easily explained,” said her father. “The
atmosphere, by its pressure, ultimately forced its way through the
edges of the sucker; its interior, therefore, became filled with air,
and it consequently balanced the external weight, which had before
confined it.”
“I think,” said the vicar, “that Tom must now surely understand the
theory of the leathern sucker; what say you, my boy? Cannot you exclaim
with Persius, ‘_Intus_ et in _cute_ novi.’”
“Which I suppose,” observed Mr. Seymour, “you would construe, ‘Well do
I know the nature of the _cavity_, and the operation of the _leather_.’”
“Exactly,” answered the vicar.
“Then never more protest against the vice of punning, for a more
atrocious specimen of the _lusus verborum_ was never sported by the
most incorrigible Johnian: but, to your classical fancy, any object
enclosed in a Latin shrine appears as a deity.”
The vicar had just drawn up his person into a suitable attitude for
combat, and would, no doubt, have defended himself against this
unexpected attack with his usual address, had not a circumstance
occurred, which put an abrupt termination to the discourse.
“See! see!” exclaimed Louisa; “what can have happened? There is Jerry
Styles, with a crowd of villagers, running towards us in the greatest
state of agitation and alarm.”
“Jerry Styles? It is, indeed, as you say, my faithful clerk,” cried the
vicar. “Bless me,--bless me, what can have happened! Is the vicarage on
fire? Has the old roof at last tumbled into the chancel?”
“Oh, sir!--oh, my dear sir!” vociferated the terrified servant of the
church, whose blanched cheeks made his red nose appear like a volcano
burning amidst a desert of snows, “poor Tom Plank has blown the roof
off his house, and is so dreadfully wounded that it is impossible for
him to survive long, if, indeed, he is not already dead.”
“How did it happen?” exclaimed several voices.
“From a _speriment_! a _speriment_! it all came from a _flossical
speriment_!” replied the breathless clerk; “but, pray, gentlemen, come
directly to the village; for mercy’s sake, gentlemen, don’t delay a
moment.”
The vicar and Mr. Seymour instantly proceeded with the terrified Jerry
Styles towards the house of the unfortunate “planer of deals;” they had
not gone far before they met several other villagers, who informed them
that Dr. Doseall was in attendance upon the wounded man, and had
pronounced him to be in the greatest danger.
On their arrival at the house, the roof of which they at once perceived
had not suffered in the fray, they learned that Tom Plank had been
engaged in some experiments for producing a _vacuum_, in the
prosecution of his new scheme of propelling passengers through a
funnel; and that, in firing a mixture of oxygen and hydrogen gases, he
had neglected the usual precaution, and blown up his apparatus; the
stop-cock had been unceremoniously expelled through the window, and, in
its passage, had ungraciously flown in the face of its master, and left
the traces of its indignation in the form of a very slight scratch upon
his forehead; this accident, with a burn of the fingers, was the only
personal injury he had sustained.
“Come, come,” said Mr. Seymour, “no mischief has occurred, and the
accident will, I trust, teach you more caution for the future. You are
not the first adventurer who has _burned_ his _fingers_ by _bubble_
speculations, and in vain attempts to _raise the wind_.”
Dr. Doseall, however, with a countenance of stern composure, and a
portentous shake of the head, maintained that the accident was by no
means so trifling as Mr. Seymour appeared to suppose; and, in
conformity with this view of the case, he had prudently bled his
patient largely, and directed sundry mixtures and lotions, together
with a _quantum sufficit_ of laudanum, in order, as he said, “to keep
down the swelling and puffing of the head,” although there were those
present who were uncharitable enough to hint, that the _swelling_ and
_puffing_ related rather to the Doctor’s bill and character, than to
the patient’s pericranium.
After a short interval, engaged in answering the numerous enquiries of
the anxious spectators, the doctor, with an air of awful solemnity,
advanced to the sufferer, and offered him a bolus of no ordinary size;
upon the virtues of which he descanted in most touching language.
“Avaunt!” exclaimed Mr. Seymour, “do you suppose that Tom Plank has the
throat of the great dragon which the Indians believe to swallow the
moon, and thus to produce the phænomena of lunar eclipses? Away with
thy treacle and pipe-clay; there cannot be the least pretext for this
parade of remedies; I warrant you that Dame Nature, unless she be put
out of humour by your officious interference, will heal the scratch
before to-morrow’s sunrise.”
The doctor, as our readers will readily imagine, was very justly
incensed at this ex-professional interference. His first determination
was to treat the matter as a joke, and to turn the laugh against the
unmannerly intruder; but the abortive smile was strangled in its birth,
and suffused the hue of death over his visage. Never did a countenance,
in the focus of his blue window bottle, by candle-light, exhibit a more
ghastly pallor; and we can scarcely predict what might have been the
consequence, had he not instantly administered a consoling cordial to
his nostrils; for, be it known, that the doctor took snuff in the same
extravagant proportion as his patients took physic. Having by these
means recovered his self-possession, he instantly seized his cane, and
waving it with as much dignity as Jove is said to brandish his thunder,
he departed in deep dudgeon, which was betrayed by a snarl, not unlike
that of a hungry dog who is unexpectedly despoiled of a savory bone,
and by a contortion of the face, similar to that we have observed in a
child who has unfortunately mistaken Aloes for Liquorice.
No sooner had the man of wrath and phials retreated from the field of
blood, than Mr. Twaddleton advanced to the suffering artist, deeming
the moment of bodily fear as affording a favourable opportunity for an
attempt to reclaim him from the error of his ways. “Tom Plank,” said
he, in a mild tone, “hadst thou given ear to the warning voice of thy
spiritual pastor, and, instead of ridiculing his advice at the sixpenny
club, hadst, like a true Christian and worthy parishioner, given heed
unto it, thou wouldst not, at this time, have been placed in such
bodily peril. Mr. Seymour has consoled thee by his opinion; sincerely
shall I pray that his judgment may be confirmed by the result, and that
the visitation may have a salutary influence upon thy future conduct.
Quit the pursuit of these bubbles, and leave wiser men to investigate
the secrets of nature; let me exhort thee to return to thy craft, sow
where thou canst reap; we cannot have figs from thorns, nor grapes from
thistles; remember the proverb, ‘an emmet may work its heart out, but
can never make honey.’ One word more and I have done--suffer not the
artist whose profit it is to furnish thee with materials, to flatter
and cajole thee--‘the dog wags his tail, not for thee, but for thy
bread.’”
As the party left the house, they met Mrs. Seymour, with Tom and
Louisa, whose looks sufficiently testified the anxiety they had
suffered.
“Is it all over? Is he dead?” asked Mrs. Seymour.
“No, no; he is quite safe; it was an extremely slight accident,
although Doseall wished us to believe that it was likely to terminate
in some dreadful manner. The vicar thinks that it may prove the means
of driving science _out_ of Tom Plank’s head, and I intend to make it
subservient to driving it still farther _into_ ours.”
“What do you mean?” cried Tom.
“I mean that it was an extremely apposite accident for illustrating the
subject upon which we were engaged at the moment of interruption.”
“This is the second accident then,” observed Louisa, “that will have
served us in our scientific studies. What a philosopher,” continued
she, “must Dr. Doseall become, if he profit by every accident he
witnesses!”
“Knowledge, my dear girl, is not promoted by the opportunity of seeing,
but by the faculty of skilfully observing, and reflecting upon what we
see; were it otherwise, the merit of a traveller might be at once
estimated by the number of shoes he had worn out. Whenever, therefore,
you hear of a discovery having been made _by accident_, do not, on that
account, depreciate the merits of its author. It is certainly true,
that many an important truth has been brought to light from some casual
observation(29), but the dexterity with which such observation was
applied constitutes the merit of the discoverer. Well, but to show in
what manner the accident of Tom Plank bears upon the subject under
discussion:--He had ignorantly fired a quantity of oxygen and hydrogen
gases in a tin vessel; the consequence of the combustion was the
immediate formation of a _vacuum_: and what happened? Why, the pressure
of the external air, not being any longer balanced by elastic matter in
the interior of the apparatus, crushed it with violence, as any other
enormous weight might have done; and so ended the accident, which
report magnified into a most awful catastrophe.”
As the party proceeded on their way home, they continued to discourse
on the subject of the air’s pressure.
“If the atmosphere exerts so enormous a pressure, and has so much
weight,” observed Louisa, “it is strange that it should not fall down
on the earth.”
Mr. Seymour replied, “that the air was a peculiar fluid, which, from
its elastic properties, was distinguished by the term of an _elastic
fluid_, the particles of which were too far distant from each other to
exert any cohesive attraction amongst themselves.”
“But I suppose,” said Tom, “that it gravitates, or is attracted by the
earth; what then can be the reason, as Louisa says, that it does not
fall, like any other body, to the ground?”
“And so it actually does,” replied Mr. Seymour. “The lower stratum of
the atmosphere rests upon the ground, but the strata above it do not
fall, because they are supported by the particles beneath them, in the
same manner as the water at the surface of a basin is supported by that
at the bottom: the only difference in these two cases arises from the
one being an elastic, and the other an inelastic fluid; so that the air
after compression resumes its original dimensions; and since the
atmosphere, by the action of gravity, is always in a state of
compression, so is it always endeavouring to expand itself.”
“If, then, the force of gravity were diminished,” observed Louisa, “the
air would become much lighter, and I suppose that is the true reason of
its being so much less dense in the upper regions.”
“Scarcely,” replied her father. “Have you forgotten the explanation[36]
which I lately gave you, of the diminution in the weight of bodies at a
distance from the earth’s surface?”
“I recollect it perfectly,” exclaimed Tom; “and it explained to us the
reason that a marble fell from the top of a house, and from the ball of
St. Paul’s with the same velocity.”
“And yet I am quite sure,” said Louisa, “that I have lately read an
account of the air being so extremely light upon the top of a high
mountain as to affect the breath and occasion great uneasiness.”
“I do not deny the fact, my dear; I only question your explanation of
its cause. Can it not, think you, be accounted for upon some other
principle than that of the diminished force of gravity?”
Louisa was unable to suggest any other probable reason.
“The fact, then,” said her father, “is simply this; since the air is
elastic, or capable of yielding to pressure, so, of course, the lower
parts must be more dense, or in a greater state of compression than
those which are above them. In a pile of fleeces of wool, are not the
lower fleeces pressed together by the weight of the superior ones, and
do they not lie light and loose, in proportion as they approach the
uppermost fleece, which receives no external pressure, and is confined
merely by the force of its own gravity?”
“Clearly,” said Louisa.
“Well then, we will suppose, for example, that the whole column of the
atmosphere were divided into a hundred parts, and that each of these
parts weighed an ounce; would not the earth, and all things on its
surface, be, in such a case, pressed upon with the whole hundred
ounces?”
“No one can deny that,” said Tom.
“The lowest stratum of air,” continued Mr. Seymour, “would be pressed
upon by the ninety-nine ounces above it; the next by ninety-eight; and
so on, until we arrived at the ninety-ninth stratum from the bottom,
which would, of course, be subjected to no more than one ounce of
pressure, or to the weight of the last and highest stratum.”
The children were perfectly satisfied with this simple explanation; and
Tom enquired whether, for the same reason, the water at the bottom of
the sea must not be very dense, and unlike that we are accustomed to
observe on the surface: his father, however, corrected this notion, by
stating that water, not being, like air, elastic and compressible,
would not suffer any material diminution in volume, although pressed
even by the enormous weight of the superincumbent ocean.(30)
“I have before alluded to the relative compressibility of air and
water, and the present appears a good opportunity for proving the fact
by an amusing experiment. See! here are the ‘_Bottle Imps_,’ vicar,
which you may remember I promised to introduce to your respectful
notice,” said Mr. Seymour. “In this jar of water, carefully closed, as
you may perceive, by parchment, are two little enamelled figures, which
shall be made to rise and fall, by alternately pressing upon and
removing the hand from the cover: thus.”
[Illustration: Two devil-like figures within an upturned bottle
bouncing about.]
“Why, the spirit of Simon Magus must surely possess thee!” exclaimed
the vicar.
The children, as may be readily imagined, were much astonished at so
singular an effect, and expressed much anxiety to be informed by what
mechanism it was produced. Their father accordingly proceeded with the
following explanation.
“I have here,” said he, “a figure exactly similar to those in the
bottle, which we will now examine. You will observe, that in its centre
there is a cavity terminating in a small orifice in the lower part;
this cavity may be made to contain any quantity of air, so as to give
the required buoyancy to the figure: now mark!--I press my hand upon
the parchment cover, and the figure, you perceive, descends; I now
remove the pressure, and see, it immediately reascends. The water in
the bottle, as I have told you, is incompressible; when, therefore, I
press upon the surface, it rises into the interior of the figure, and,
consequently, by compressing the air into a less space, renders it less
buoyant; but no sooner is the hand removed, than the enclosed air
resumes its former volume, and expels the intruding water; in
consequence of which the figure regains its former lightness, and
reascends. Do you understand me?” asked Mr. Seymour.
“Perfectly,” said Tom, “and many thanks for the explanation;” and in
this opinion did the whole party concur.
“Well, then,” continued Mr. Seymour, “you will now understand the use
of the air-bladder in fish, for it is constructed upon a precisely
similar principle. When the fish desires to descend, it presses upon
the bladder by means of its muscles, and thus condenses the included
air into a smaller volume.”[37]
“I now also perceive why the water at the bottom of the sea cannot be
much more dense than that on the surface; but, if we could dig a pit to
the centre of the earth, the air, in that case, would be highly dense,
because, unlike water, it is compressible,” said Tom.
“The density of the air,” replied his father, “would, undoubtedly,
materially increase as we descended. It has been calculated that, at
the distance of thirty miles below the surface, the air would have the
same density as water; and, at the depth of forty-two miles, that of
quicksilver; while, at the centre, it would be more solid than any
substance of which we have any idea, for its density would be thousands
of millions of times greater than that of mercury.”
Mr. Seymour then informed his young pupils, that after the lesson they
had just received, they would never again be puzzled by the motions of
the barometer, which had so often excited their wonder.
“As the quicksilver is contained in a closed tube, I do not exactly
understand how the air can act upon it; and if the tube were not
closed, it would of course run out from its weight,” observed Louisa.
“You are altogether in error,” said her father. “In the first place,”
he continued, “I will show you that the bulb at the lower extremity of
the tube is open, in order that the quicksilver may freely communicate
with the atmosphere, upon which, indeed, its action entirely depends;
while the upper space is a perfect vacuum, so as to obviate any
counteracting pressure. As to the quicksilver running out, have you so
soon forgotten that the air presses upon every body on the surface of
the earth, in the proportion of about fifteen pounds upon every square
inch? Now it is from this circumstance that the column of quicksilver
is sustained in the tube, the ascent and descent of which thus
indicates the varying pressure of the atmosphere; so that, when the
barometer falls, we know the air presses less heavily upon the earth,
and the contrary when it rises.”
“That I understand: but what can cause the pressure of the air to vary
at different times?” asked Tom.
“Cannot you imagine the atmosphere to be an airy ocean, and to be
therefore thrown into enormous waves, so that we may sometimes have a
longer column of air above us than at other times; this is one
explanation, there may be other causes not so intelligible,” answered
Mr. Seymour. “But enough of this for the present. Now, before we quit
the subject of the air’s elasticity, let us consider the philosophy of
the _pop-gun_; an amusement with which, I have no doubt, you are well
acquainted.”
“Indeed I am, papa; but do you allude to the quill, or to the wooden
pop-gun?”
“The principle in both is the same; tell me, therefore, the origin and
nature of the force which enables you to shoot your pellet to so
considerable a distance.”
“It depends upon the action of the air,” replied Tom.
“Undoubtedly: but your answer is too general; I wished you to state, in
precise terms, the changes which the air undergoes upon this occasion.
You first ram in your pellet to the further end of the tube, do you
not?”
“To be sure; and then I drive in a second pellet, and on forcing this
forward, the first flies out with prodigious force.”
“Very well: now examine what takes place; on propelling forward your
second pellet, you condense the air which is enclosed between the two,
until its elastic force becomes so great as to overcome the friction of
the first pellet; thus released, the air expands with considerable
force, and imparts a rapid motion to the pellet.”
“I have frequently heard of the air-gun,” said Louisa; “I suppose it
depends upon a similar principle.”
“It does; and it affords a very striking example of the surprising
force which air is capable of exerting, when condensed to a
considerable degree; for, by means of this instrument, bullets may be
propelled with a force very nearly equal to that of gunpowder.”
“It is a curious fact,” observed the vicar, “that although the air-pump
is a modern invention, yet the air-gun, which is so nearly allied to it
in the construction of its valves and condensing syringe, should have
existed long antecedent to it; for it is recorded that an air-gun was
made for Henry IV. by Marin, of Lisieux, in Normandy, as early as 1408;
and another was preserved in the armoury at Schmetau, bearing the date
of 1474.”
“But the air-gun of the present day,” said Mr. Seymour, “is very
different from that which was formerly made, and which, like the
pop-gun, discharged but one bullet, and that after a long and tedious
process of condensation, while it is now made to discharge five or six
without any visible variation of force, and will even act upon a dozen,
but with less effect.”
“I feel very curious to learn something more about this air-gun,” said
Tom.
“There is a reservoir for the condensed air,” replied Mr. Seymour,
“which is secured by a nicely constructed valve, and which is made to
open by pulling the trigger of the gun, so that a portion only of the
air is disengaged, which, rushing into the barrel, gives motion to the
ball.”
“But how is the condensed air introduced into the reservoir?” asked Tom.
“By means of a condensing syringe,” replied his father; “but I will
take an opportunity of exhibiting the instrument in operation.”
The reader will be pleased to recollect that the major agreed to pay a
passing visit to the vicarage; it now becomes our duty to record what
happened upon that memorable occasion; and we, perhaps, cannot better
represent the nature of the discussion that took place than by relating
the account as it was given by the belligerent parties themselves in
conversation with Mr. Seymour.
“Well, gentlemen,” said Mr. Seymour, “is it peace or war? I trust you
have amicably adjusted all your differences.”
“Upon my word,” answered the vicar, “I have just reason to complain of
the major’s unjustifiable scepticism upon points that are perfectly
unquestionable.”
“You continue then to smart under the major’s stinging criticisms,
‘_majore sub hoste_.’ There is a Latin pun for your consolation,” said
Mr. Seymour.
“The vicar alludes, I suppose,” said the major, “to the doubt I
expressed respecting the authenticity of his leathern money?”
“That is one of the many subjects upon which, I must say, you have
betrayed a deficiency in historical knowledge. Seneca informs us that
there was anciently stamped money of leather; and the same thing was
put in practice by Frederick II. at the siege of Milan; to say nothing
of an old tradition amongst ourselves, that, in the confused times of
the barons’ wars, the same expedient was practised in England.”
“You strangely mistake me,” replied the major; “I never questioned the
truth of these historical statements; I know full well that numerous
substances have, at different times, and in different countries, been
adopted in exchange, as conventional representatives of property. I
have already stated that cattle were employed as the earliest measure
of value (31). We find, for instance, in Homer, that the golden armour
of Glaucus was valued at a hundred, and that of Diomedes, at ten oxen.
Among the Indians, _cowries_, or small shells, are used; and the
Abyssinians employ salt, bricks, and beads for this very purpose; the
ancient Britons are said to have circulated iron rings as money. The
Hollanders, we know, coined great quantities of pasteboard in the year
1754; and Numa Pompilius certainly made money both of wood and leather.”
“And yet you doubt the authenticity of my leathern money, which I am
fully persuaded was coined in 1360, by John, king of France, who,
having agreed to pay our Edward the Third the sum of 3,000,000 golden
crowns for his ransom, was so reduced as to be compelled to a coinage
of leather for the discharge of his household expenses.”
“I have only questioned the authenticity of that specimen which I saw
in your cabinet,” replied the major: “and so must any person who views
it through a medium unclouded by prejudice. I will stake my whole
library to a horn-book, that our friend Mr. Seymour will agree with me
in pronouncing it a fragment of the heel of an old shoe: let him
observe the perforation, and say, if he can, that it has not been
produced by a nail or peg. But really, my dear Mr. Twaddleton, you have
forced me, much against my inclination, into this controversy.”
“Very good, sir! very good! the heel of an old shoe, forsooth! But I
thank you, Major Snapwell,” exclaimed the vicar with some warmth; “I
thank you, sir. Your assertion, while it evinces your own want of
historical information, establishes, beyond doubt, the authenticity of
my treasure, and the triumph of my opinion.”
“Assuredly,” said Mr. Seymour, with a wicked smile; “I dare say there
may be numerous holes in this leathern coin; for many have been the
antiquaries who have, doubtless, _pinned_ their faith upon it.”
“Psha, psha!” cried the vicar; “for once, at least, Mr. Seymour, let me
entreat you to be serious; the subject, sir, is important, and merits
your respect. It is from that very hole that I am enabled to identify
the coin: yes, major, from that very hole, which you affect to despise,
I am enabled to derive its principal claim to antiquity. Are we not
expressly informed, that the leathern money of John of France had a
little nail of silver driven into it?”
“Well, then,” continued the major, “what say you to that tell-tale
stitch, which I so unfortunately picked out with my penknife?”
“Admirable ingenuity! most refined sophistry! provoking perversion!”
exclaimed the vicar. “It is really amusing to observe the address with
which the prejudiced observer distorts every fact to his own advantage.
Why, bless me, sir, that stitch is strong enough to drag fifty such
opponents out of the slough of unbelief.”
“Do explain yourself,” said Mr. Seymour.
“Explain myself! the stitch speaks for itself, sir. Were not these
leathern coins strung together in different numbers, to facilitate
payments? For, you will admit, that it would have been extremely
inconvenient to have coined single pieces of leather, of different
denominations. But stop, sir, stop; look at this, look at it, major,
with care and attention. That,” said the vicar, as he drew a small coin
out of his waistcoat pocket with an air of imperturbable gravity and
self-satisfaction, “is a current halfpenny, in lead, of James II; and
if your eyes are not hoodwinked by prejudice, you may probably perceive
a piece of copper in its centre, which, we are told, was thus
introduced for the purpose of rendering the currency lawful.”
The dinner was announced before the conclusion of the discussion; and
as the reader will probably agree with us in thinking that a question
of such grave historical importance ought not to be decided without due
care and deliberation, we shall afford the disputants a reasonable time
for reflection, and put an end to the chapter.
-----
Footnote 36:
See page 28.
Footnote 37:
In the cod-fish the air bladder is familiarly called the _sound_.
------------------------------------------------------------------------
[Illustration: Two boys blowing bubbles from tobacco-pipes.]
CHAPTER XII.
_The Soap-Bubble.--The Squirt.--The Bellows; An Explanation of
their several parts.--By whom the instrument was invented.--The
sucking and lifting, or common Pump._
“Tom,” said his father, “bring me a saucer with some hot water; a piece
of soap, and a tobacco-pipe. I have promised to teach John the art of
blowing soap-bubbles.”
Tom immediately proceeded to execute his commission, and shortly
rejoined the party on the lawn, bringing with him all the necessary
implements for bubble-blowing. John, under the direction of his
brother, made the lather; and Mr. Seymour, turning towards the elder
children, asked them whether they understood the philosophy of the
operation they had just witnessed; they were, however, unable to return
a satisfactory answer, and their father, therefore, proceeded as
follows:--
“Most liquids, by agitation, exhibit the appearance of froth, in
consequence of the escape of the air in small bubbles, which had been
forced into them by the operation. If, however, the liquid be viscid
and tenacious, like soap and water, the air is, as it were, imprisoned
in the mass, producing the appearance which is commonly called
_lather_.”
Louisa here enquired “Whether the air did not escape with more or less
readiness, according to the degree of resistance it met with in the
liquid?”
“I thank you,” said Mr. Seymour, “for having so kindly assisted me in
the explanation.”
Louisa smiled at this mark of her father’s approbation, and Mr. Seymour
proceeded,--“It is on that very account, that spirit, after it has been
shaken, so soon regains its transparency: for, in consequence of the
superior lightness of that fluid, and the little cohesion which
subsists between its particles, the air makes a rapid escape. In like
manner we may account for the spongy appearance which gives such
superiority to our bread; in that case, the air disengaged during the
fermentation of the dough cannot escape through so viscid a mass; it
therefore remains, and thus produces the eyes or bubbles, which you may
always observe in every well-baked loaf.”
“See, papa,” exclaimed Tom, “the bubbles which John has blown in the
lather, are not round, but angular figures--they appear to be like the
hexagons which we used to cut out for our _papyro-plastics_.”
“They are certainly hexagonal,” replied Mr. Seymour; “and the form
arises from the pressure of the bubbles upon each other. The same
appearance is to be seen in the pith of vegetables, when examined by
the microscope, and is the result of the general reaction of the solid
parts upon each other: but let us proceed to blow some bubbles. Plunge
the bowl of the tobacco-pipe into the lather.”
Tom obeyed his father’s directions, and blowing through the stem
produced a bubble.
“See! see!” cried Louisa, “what a beautiful bubble! but there is a
quantity of soap hanging to its under part.”
“I will take it off with my finger,” said Mr. Seymour.
“There it goes!” exclaimed Tom.
“What beautiful colours it displays! as bright and gaudy as those of
the rainbow!” observed his sister.
“It has burst!” cried Louisa.
“Ah! my dear children,” murmured the vicar, with an air of pensive
gravity, “‘_Tenues secessit in auras_,’ as the poet has it. Even thus
is it with all the full-blown bubbles of our fancy, raised by the
breath of hope; the moment they appear most vivid and promising to our
imagination, they vanish ‘into air, into thin air,’ like the gaudy and
unsubstantial soap-bubble you have just witnessed: but proceed to blow
another.”
“There is one!” exclaimed Louisa;--“see, it is of an oblong shape, like
an egg!--there it goes!--but I declare it is now perfectly
round!!--what can be the reason of its changing its figure?”
“I am glad you have asked that question, because my answer will serve
to illustrate an important property of air, and which, indeed, is
common to all fluids. While the upper part of the bubble was attached
to the bowl of the pipe, its gravity being resisted, drew it into an
elliptical form; but the instant it was detached, the contained air
pressed equally in all directions, and the bubble, in consequence,
became a perfect sphere.”[38]
“I do not exactly understand what you mean ‘by pressing equally in all
directions.’”
“The expression is surely sufficiently intelligible. Did you not learn
in our conversation of yesterday, that air has weight, and exerts a
pressure as much upwards as downwards and laterally? Were this not the
case, how could the air in the interior of our bodies counteract the
pressure of the atmosphere? The form of the bubble proves the same fact
in a different way; for, had the air in its cavity pressed more in any
one direction than in another, the bubble could not have been round,
or, to speak more correctly, a sphere.”
“What are you musing about?” cried the vicar, who had observed the
attention of the boy riveted upon the bowl of the tobacco-pipe: “I am
sure, from your countenance, that some circumstance is puzzling you.”
“You are right, my dear sir; I was just then thinking how it can
possibly happen, that the bubble should not have a hole in its upper
part; for, while I am blowing it up, there must, of course, be a
communication between my mouth and its interior, or else how could the
air pass into it?”
“True,” said his father; “but the act of throwing it off from the bowl
of the pipe will unite this breach; for there exists a strong cohesive
attraction between the attenuated particles of the lather; you will,
therefore, perceive that, on this account, the bubble will be more
readily and securely separated by a lateral than a perpendicular motion
of the pipe.”
“I wish,” said Tom, “that I could discover some method of preventing
their bursting so soon, for there is scarcely time to examine them
before they vanish. What can be the cause of their short duration?”
“Consider, my dear boy, the frailty of their structure, and I think
that the precarious tenure of their existence will cease to astonish
you; indeed, the wonder is, that they should endure so long. The film
of which they consist is inconceivably thin,[39] so that the slightest
impulse will be apt to rupture them; besides which, there must be a
considerable evaporation going on from their surface, while the
contraction of the contained air, from change of temperature, must also
tend to limit their duration. You must likewise remember that the
soap-lather will have a tendency to gravitate towards the depending
part of the bubble, and, consequently, by quitting the upper portion,
to render it of still greater tenuity. This last effect might, perhaps,
be obviated, in some measure, by giving a rotatory motion to the bubble
around its axis; but this, again, would accelerate the evaporation:
which, after all, is the principal cause of the shortness of its
duration; so that, unless this latter effect could be remedied, I
despair of suggesting any expedient by which the frail existence of our
airy structure could be protracted. You must, therefore, seek, from a
succession of bubbles, the prolongation of an amusement which no single
one can afford you.”
“And could not the evaporation be prevented?” asked Tom.
“If the bubble were blown in a glass vessel, and the latter immediately
closed after the operation, it would remain for some time; I remember
having once preserved a bubble in this manner for a very considerable
period.”
Tom, however, did not appear to relish this scheme; as, he said, the
great sport arose from watching the movements of the floating bubble;
the boy, accordingly, determined to pursue the amusement in the usual
manner. His father, however, observed, that by mixing a solution of
isinglass with the soap lather, larger, as well as more lasting bubbles
might be blown; and Tom accordingly determined to make the experiment.
During this dialogue, little John had succeeded, for the first time, in
launching the airy bauble. Imagination always tinges the objects of our
first efforts with brilliant tints: no wonder, therefore, that John,
with a shout of ecstasy, should have pronounced it to have been the
most beautiful bubble he had ever seen: in truth, the sun was shining
brightly, and the colours thus produced very justly excited the
admiration of all present.
“I cannot understand the cause of these beautiful colours,” said Louisa.
Mr. Seymour expressed a fear that, in their present state of knowledge,
they would be scarcely able to understand the explanation he should
afford them. “But,” said he, “I believe you know that a ray of light is
divisible into seven colours, and that when it passes through certain
media, or is reflected from certain surfaces, this division is
effected, and the various colours produced(32). The film of the soap
bubble is one amongst the latter bodies; but I must refer you, for
farther information upon this subject, to Mrs. Marcet’s beautiful
account of ‘Refraction and Colours.’”
“Now, Tom,” said his father, “fetch your squirt, for we have not yet
finished our enquiry into the effects of the air’s pressure.”
The squirt was produced; but it was out of repair: for, on attempting
to fill it with water, the instrument entirely failed in the
performance of its office.
“I see the defect,” said Mr. Seymour, “which a little string will
easily remedy.”
A piece of string was instantly produced from that universal depot, the
breeches pocket of a school-boy. Mr. Seymour said he should bind a
portion of it around the end of the piston.
“What do you mean by the _piston_?” enquired Tom.
“The rod which moves up and down in the cylinder, or tube; and, unless
its end fit so exactly as to prevent the admission of air, it is clear
that the squirt cannot draw any water. It was for the purpose of making
this part fit tightly that I wanted the string, and you will now
perceive that the instrument is ready for use:--fetch me a vessel of
water.”
Tom soon produced the water, and, on placing it on the ground,
requested that he might be allowed to fill the squirt. This he
accordingly effected without difficulty, and, on pressing down the
handle, he projected a stream of water to a considerable distance.
“I perceive,” said Tom, “that the stream describes a curve, like my
ball.”
“To be sure; it is under the joint influence of the same forces, viz.
that of projection and of gravity. But explain the operation of the
squirt.”
“As soon as I raised the piston, an empty space was left in the lower
part of the cylinder, which I suppose would have remained as a
_vacuum_, had not the water rushed into it.”
“And why did the water rush into it?”
Tom hesitated.
“Was it not, think you, owing to the pressure of the atmosphere upon
the surface of the water? When you raised the piston, the air above it
was also raised, and ultimately driven out by the force of the
ascending piston; and since the air could not find any entrance from
below as long as the point was under the water, the interior of the
squirt would necessarily have remained quite empty, or have been a
vacuum, had it not been for the weight of the atmosphere, which, not
having any counteracting pressure, drove the water into the tube, and
thus filled it; and which, by pressing down the piston, you again
expelled with considerable force.”
“Your explanation,” cried Louisa, “is so clear and intelligible, that I
feel quite confident I could now explain any machine that owes its
action to the exhaustion of the air, and the pressure of the
atmosphere.”
“If that be your belief,” said Mr. Seymour, “I will not lose a moment
in putting your knowledge to the test.--Tom, do you run into the house,
and fetch hither the kitchen bellows.”
The bellows were produced, and Louisa having been desired by her father
to explain the manner in which they received and expelled the air,
proceeded as follows: “Upon raising the upper from the under board, the
interior space of the bellows is necessarily increased, and immediately
supplied with an additional quantity of air, which is driven into it by
the pressure of the atmosphere; when, by pressing down the upper board,
it is again expelled through the iron tube or nosle.”
“To be sure,” said Tom, “in the same manner that the water was expelled
from my squirt, when I pushed down the handle.”
“So far you are quite correct,” said Mr. Seymour; “but you have not yet
told us the use of the hole in the under-board, and which is covered,
as you perceive, with a movable flap of leather: it is termed a valve,
or ‘_wind-clap_.’”
“That,” replied Tom, “is for the purpose of admitting the air, when we
raise up the board.”
“Exactly so; and also to prevent the air from passing out again, when
you press it down. I wish to direct your attention particularly to this
contrivance, because, simple as it may appear, its action will teach
you the general nature of a valve. Without it, the operation of filling
the bellows with air would have been so tedious as to have destroyed
the utility of the instrument; for the air could, in that case, have
only found admission through the nosle, and that, again, would have
been attended with the additional disadvantage of drawing smoke and
other matter into its cavity; when, however, you raise up the board,
the air, by its external pressure, opens the wind-clap inwards, and
thus finds an easy entrance for itself; and when you press the board
downwards, the air, thus condensed, completely shuts the valve, and its
return through that avenue being prevented, it rushes out through the
tube.”
The children were much pleased with the simplicity of this invention,
and Tom enquired of the vicar who first thought of it.
“We are informed by Strabo,” replied Mr. Twaddleton, “that Anacharsis,
the Scythian philosopher, who lived in the time of Solon, about six
hundred years before Christ, invented the bellows, as well as the
anchor, and potter’s wheel; but,” he added, “there is some reason to
doubt the truth of this statement. The bellows, however, were certainly
known to the Greeks; and the great poet Virgil alludes to them in his
fourth Georgic:[40]
----‘Alii taurinis follibus auras
Accipiunt redduntque.’”
Mr. Seymour now proposed that they should proceed to consider the
structure and operation of the pump.
“I suppose,” said Louisa, “that the pump raises water in the same
manner as the squirt.”
“Exactly upon the same principle,” replied her father; “but the
machinery is a little more complicated, since its object is not to
force the water out of the pump at the same end of the pipe at which we
draw it in. We will, however, proceed to the stableyard, and examine
the pump; and do you, Tom, provide a piece of chalk, in order that I
may make a sketch of some of its principal parts.”
The party immediately proceeded; and, as they walked along, Mr. Seymour
desired the children to remember that the weight of the atmosphere was
estimated as being equal to that of fifteen pounds upon every square
inch of surface; and that the moment the water arrived at such a height
as to balance that pressure, it could ascend no higher: he added, that
the altitude at which such a balance took place was about 32 or 33 feet
above the surface.
“If that be the case,” said Louisa, “the pump, of course, can never
raise water from any well of greater depth than that which you state.”
“Not without some additional contrivance, which I shall afterwards
explain to you,” replied Mr. Seymour.
The party had, by this time, arrived at the pump; its door was opened,
and as much of the apparatus exhibited as could be conveniently
exposed. Mr. Seymour then chalked the annexed sketch upon the stable
door.
[Illustration: Diagram of a water-pump’s mechanism.]
“Is that a pump?” asked Tom: “I should certainly never have guessed
what you intended to represent.”
“It is not a perspective drawing, my dear, but a representation of the
different parts as they would appear, were it possible to cut the pump
in halves, from top to bottom, without disturbing any of its
arrangements. A drawing of this kind, which is frequently used for the
sake of explanation, is termed a _section_.”
Mr. Seymour here took an apple from his pocket, and having cut it in
two, observed that the surfaces thus exposed presented _sections_ of
the fruit. This illustration was understood by all present, and Mr.
Seymour continued, “I have here, then, a section of the common
household pump. A B is the cylinder or barrel; P the air-tight piston
which moves or works within it, by means of the rod; Q is the
‘suction,’ or ‘feeding pipe,’ descending into a well, or any other
reservoir; S the valve, or little door, at the bottom of the barrel,
covering the top of the feeding pipe; and there is a similar valve in
the piston, both of which, opening upwards, admit the water to rise
through them, but prevent its returning. As this part of the apparatus
is no less ingenious than it is important, I will sketch the valve, or
_clack_, as it is termed by the engineer, on a larger scale.”
Their father then chalked the annexed figure; from which its
construction was rendered perfectly intelligible to the children.
[Illustration: Open valve.] Mr. Seymour proceeded: “When the pump is in
a state of inaction, the two valves are closed by their own weight;
but, on drawing up the piston P, from the bottom to the top of the
barrel, the column of air, which rested upon it, is raised, and a
vacuum is produced between the piston and the lower valve, S; the air
beneath this valve, which is immediately over the surface of the water,
consequently expands, and forces its way through it; the water then
ascends into the pump. A few strokes of the handle totally exclude the
air from the body of the pump, and fill it with water: which, having
passed through both valves, runs out at the spout.”
“I understand how water may be thus raised to the elevation of 32 feet,
but I have yet to learn the manner in which it can be raised above that
distance,” said Louisa.
“It is undoubtedly true that, if the distance from the surface of the
water to the valve in the piston exceed 32 feet, water can never be
forced into the barrel; but you will readily perceive that, when once
the water has passed the piston valve, it is no longer the pressure of
the air which causes it to ascend; after that period, it is raised by
lifting it up, as you would raise it in a bucket, of which the piston
formed the bottom; and water, having been so raised, cannot fall back
again, in consequence of the valve, which is kept closed by its
pressure. All, therefore, that is necessary, is to keep the working
barrel within the limits of atmospheric pressure; we have then only to
fix a continued straight pipe to the top of the barrel, and to lengthen
the piston rod in the same proportion, and the water will continue to
rise at each successive stroke of the pump, until at length it will
flow over the top of the pipe, or through a spout inserted in any part
of its side. The common pump, therefore, is properly called the
_sucking_ and _lifting pump_.”
The party expressed themselves fully satisfied; and Tom enquired who
invented the machine.
“It is an instrument of great antiquity,” replied his father: “its
invention is generally ascribed to Ctesebes of Alexandria, who lived
about 120 years before Christ; but the principle of its action was not
understood for ages after its invention. The ancients entertained a
belief that ‘Nature _abhorred_ a vacuum;’ and they imagined that, when
the piston ascended, the water immediately rushed forward to prevent
the occurrence of this much dreaded vacuum. In the seventeenth century
a pump was constructed at Florence, by which it was attempted to raise
water from a well to a very considerable altitude, but it was found
that no exertion of this machine could be made to raise it above 32
feet from its level. This unexpected embarrassment greatly puzzled the
engineer, until Galileo suggested that the pressure on the water below
must cause its ascent into the pump, and that, according to this
theory, when it had risen 32 feet, its pressure became equivalent to
that of the atmosphere, and could, therefore, not rise any higher; and
as they did not, at that time, understand the construction of the
piston valve, the design was abandoned. It is now time to conclude your
lesson. To-morrow I hope we shall be able to enter upon the subject of
THE KITE.”
-----
Footnote 38:
A scientific friend observed to the author, that, as the globe
possesses less surface than any other figure of equal capacity, it is
of all forms that which is best calculated to allow the closest
approximation of the particles of soap and water; and as there must
exist amongst such particles a strong cohesive tendency, after having
been forcibly stretched out, as it were, by the air blown into the
bubble, it follows that, did no other cause operate, the bubble would
assume the spherical form.
Footnote 39:
Not exceeding the two millionth part of an inch.
Footnote 40:
Line 171.
------------------------------------------------------------------------
[Illustration: Two boys causing havoc by upsetting a washerwoman.]
CHAPTER XIII.
_The Kite.--Its construction.--The Tail.--An Author’s
meditations among the catacombs of Paternoster Row.--Works
in their winding sheets.--How Mr. Seymour strung puns as
he strung the Kite’s tail.--The Vicar’s dismay.--The
Weather, with the hopes and fears which it alternately
inspired.--Kites constructed in various shapes.--The
figure usually adopted to be preferred.--The flight of the
Kite.--A philosophical disquisition upon the forces by
which its ascent is accomplished.--The Tail.--A Discourse
on the theory of flying.--The structure and action of the
wings of birds.--A series of kites on one string.--A Kite
Carriage.--The Messenger.--The causes and velocity of wind
explained._
The children were summoned into the library, and informed by their
father that he was at leisure to explain the philosophy of the kite; a
subject with which Tom had repeatedly expressed some impatience to
become acquainted.
“It is a beautiful day,” exclaimed the boy joyously; “and there is such
a delightful breeze, that I should really call it a complete
_kite-day_.”
“Gently, my fine fellow,” replied Mr. Seymour: “the bird must be
fledged, ere it can fly. We have not, as yet, any kite: for you know
that the one you possess is shattered beyond the possibility of repair.”
“True, papa; but could not Robert just step into the village and buy
one? I saw several kites in the shop of Peg Robson yesterday.”
“I do not doubt it, my boy; but the kites which are to be found in the
toy-shop are made to sell, rather than to fly; and to _raise the wind_,
for the benefit of the vender, rather than to be raised _by it_, for
the amusement of the purchaser: we must, therefore, construct one for
ourselves; and see, I have, accordingly, prepared all the necessary
materials for the purpose. I have here, as you perceive, a straight
lath of deal, about three-quarters of an inch wide, and less than a
quarter of an inch thick, and about four feet in length; this is quite
ready for forming the standard, or _back-bone_ of the kite: and now for
the bow. The cooper has complied with my directions, and sent an unbent
hoop, as free as possible from knots; you observe that it is about the
same length as the lath, but it will be necessary to pare it down a
little at each end, in order to make it bend more readily to the
required shape.”
[Illustration: Diagram of a kite, labeled a through f.]
This having been accomplished, Mr. Seymour proceeded to form the
framework of the kite in the following manner. He first ascertained the
central point of the bow, by balancing it on his fore-finger; he then
affixed that point, by means of string, to the lath, at _c_, about an
inch and a half from its upper extremity; a notch was next cut in each
end of the hoop, or bow, _a d_; having fixed the string in the notch,
_a_, he drew it through another, _e_, previously cut in the bottom of
the lath, and carried it to the opposite end of the bow _d_; the
skeleton now presented the usual form, of the kite. The next point,
therefore, was to ascertain whether the two sides of the bow were in
equilibrio, which he determined by balancing the lath on the finger,
and observing whether it remained horizontal, or dipped on either side.
This adjustment having been accomplished, Mr. Seymour next continued
the string from _d_ across the skeleton to the opposite notch _a_,
giving it one turn round the lath in its way; from _a_ it was carried
to _f_, and wound round the top of the lath, and then again fastened at
_d_; from _d_ it was extended rather more than midway down the lath,
and having been secured at _b_, was finally carried to, and secured in
the notch _a_. The framework was now pronounced by Mr. Seymour to be
complete.[41]
The next part of the process was to cover it with paper. Mr. Seymour
observed, that the best kind which could be employed for this purpose
was that known amongst stationers by the name of _fan paper_, so called
from its being manufactured for the use of the fanmaker; its merits, he
said, depended upon the size of its sheets, as well as upon the
thinness and firmness of its texture: this, however was not at hand; he
was therefore obliged to rest satisfied with its best substitute, viz.
folio sheets of large thin post.
The party now went “ding-dong” to work; paper, paste, and scissors were
immediately put in requisition. Sheets of paper were laid smooth on the
table, and so arranged that each sheet overlapped its neighbour about
half an inch. The skeleton of the kite was then placed upon them, and
the paper was cut to its figure; a margin, of about three-quarters of
an inch, having been left around it, except over the bow, where the
margin was extended to an inch in width: this arrangement was for the
purpose of allowing the paper to turn over the framework, when pasted
to it. This part of the work having been completed, and a sufficient
time allowed for the drying of the paste, Mr. Seymour proceeded to fix
the string, usually termed the _belly-band_: for this purpose two holes
were drilled through the lath, at equal distances from its edges; the
upper one about a fifth part of the length of the kite from the top,
the lower hole rather more than the same distance above its extremity.
The last, and by far the most important point, was to make the loop in
the _belly-band_. If the kite be accurately constructed, its proper
place may be easily found by extending the band, right or left, on the
surface of the kite, and then marking the string at a point which lies
in a line drawn from one end of the bow to the other; the loop must be
made a little above such a point. If the kite be now suspended by this
loop, the two ends of the bow ought to preserve a balance, and the
lower extremity should dip below the upper part of the kite.
As Louisa observed the extreme care with which her father adjusted this
part of the machine, she enquired into its use.
“I was myself about to put the same question,” said her mother; “for
its adjustment would appear to require as much accuracy as that of the
sash of a girl of sixteen.”
Mr. Seymour informed them, they would hereafter find that the steady
ascent of the kite into the air entirely depended upon such accuracy.
“Have you not seen, Tom,” asked he, “a kite rise sideways, or _plunge_,
as it is called?”
Tom said he had often experienced that difficulty at school, but that
he had attributed it to some defect in the tail.
“An error in the construction of the tail may, certainly, be
occasionally the cause of such an accident, but it is more generally
referable to an improper position of the loop: if the kite _plunges_,
you may conclude that this loop is placed too high; and should it whirl
round in the air, you may infer that it is too low.”
During this conversation Mr. Twaddleton entered the apartment; Tom was
anxious to show him his newly-constructed kite, and, while the party
were asking him numerous questions, Mr. Seymour observed, that the
vicar would be more profitably employed in making _bobs_ for the string
of the tail, than in finding answers for their string of questions.
Mrs. Seymour, and her daughters, with Tom and the vicar, were,
accordingly, placed round the table, for the purpose of carrying this
project into effect, by a suitable division of labour. It was arranged
that Mrs. Seymour should cut the paper, the vicar fold it, and Mr.
Seymour tie it on the string.
“How long ought the tail to be?” asked Tom.
“And of what shape should the papers be cut?” enquired Louisa.
“And at what distances are they to be placed from each other on the
string?” said Mrs. Seymour.
“I will answer all your queries,” replied the father, “by giving you a
dissertation upon this part of our machine.”
“We shall now have an harangue,” exclaimed the vicar, “as long as the
tail itself; but pray proceed.”
“The tail should never be less than twelve, and should it even amount
to twenty times the length of the kite, its appearance in the air will
be more graceful; this, however, must be regulated by the weight of the
string, and by the length and thickness of the pieces of paper of which
the tail is composed. The length of each ought to be about three inches
and a quarter, and an inch and a half in breadth, and it should be
folded four times longitudinally; each of these _bobs_, as they are
called, must be placed at regular intervals of three inches.”
“And with respect to the size of the wings?” asked the vicar.
“I should not recommend any wings; if the kite be well made, there
cannot be any advantage from such appendages. Having now answered your
several questions, let us proceed with our work.”
“But where is the paper?” asked Mrs. Seymour.
“Apropos,” answered her husband; “the box in which the London toys were
packed contains a quantity that will answer our purpose.”
The box was accordingly placed on the table.
“Why, what a most extraordinary miscellany!” cried the vicar; “the army
of Mithridates could not have consisted of a more incongruous mixture.
I perceive,” added he, as his enquiring eyes glanced from sheet to
sheet, “we have here a fragment of almost every description of literary
and scientific work.”
“The market,” observed Mr. Seymour, “is supplied with waste paper from
the catacombs of Paternoster Row, which may be truly said to ‘level all
distinctions.’ Without intending any offence by a pun, my good vicar,
what a _tale_ will this box unfold! I never open a magazine of this
waste paper, without feeling a deep sympathy for the melancholy fate of
authors: to see the strange transmigrations, and vile purposes, to
which their works are destined, is really heart-rending. That the
_lights_ of science should be consigned to the tallow-chandler! the
works of the moralist, so well calculated to _purify_ the world, to the
soap-seller! that such a book as ‘Laennec on the _Chest_,’ with Dr.
Forbes’s valuable _Cases_ in the bargain, should be _packed_ off to the
_trunk_-maker! are events which cannot fail to furnish food for
melancholy reflection. Nay, more, I have myself (can you believe it,
Mr. Twaddleton?) actually received a quantity of _ureic_ acid in a
Review of Dr. Thomson’s Chemistry! and I only yesterday learned, with
horror, that a piece of fat bacon was positively wrapped up in a page
of ‘Paris on Diet;’ while a Cheshire cheese came encased in Kitchener’s
‘Chart of the Moon.’”
“Oh, shameful! shameful!!” exclaimed the vicar: “but I can assure you,
that this unfeeling conduct of the publisher had not escaped my notice
and indignation; for I lately received a work against the slave-trade,
in the fragment of a tract on ‘the Progress of Cant;’ and a Copy of
Irving’s Orations, in an act of ‘Much Ado about Nothing;’ and what was
still worse,” continued the reverend divine, “a little work on the art
of Prognosticating the Weather, was forwarded to me in a chapter of
_Daniel’s_ Prophecies.”
“But let us quit these melancholy reflections for the present, and
proceed with our occupation.”
“If you compose the tail of your kite with these papers,” said the
vicar, “it will certainly vie with that of Scriblerus himself; you will
have a knot of divinity,--a knot of physic,--a knot of logic,--a knot
of philosophy,--a knot of poetry,--and a knot of history.”
“Never mind, my dear sir; I wager an edition of Virgil, that I shall be
able to discover in each page, with which you may present me, some
apposite allusion to the _tail_, of which it is to form a part.”
“Apposite allusion! impossible; as well might you attempt to connect
the scattered leaves of the Sibyl: for example, here is an Epitome of
the Roman History.”
“Very well,” said Mr. Seymour, “and pray is not that cur_tail_?”
The vicar dropped the paper in dismay; the treacherous design of his
friend now, for the first time, flashed across his brain with a painful
conviction, and he hastily retreated to a distant corner of the
library, or “_turned tail_,” as Mr. Seymour jocosely expressed it, in
order that he might find shelter from the pelting of a pitiless storm
of puns, which he saw, too clearly, was about to burst on his devoted
head.
On the vicar’s retiring from the table, Mrs. Seymour approached the
fatal box, observing, “that it was now her turn to explore the
Sibylline cave.”
“Here,” said she, “is a list of the prices of some newly published
works.”
“That,” replied her husband, as he cast a sly glance at the vicar, “is
re_tail_: pray, proceed.”
“We have next, I perceive, a prospectus for publishing all the speeches
in the late parliament.”
“That is de_tail_.”
Here a deep groan from Mr. Twaddleton arrested the progress of the
proceedings, and threw the whole party into a fit of laughter. As soon
as tranquillity was restored, Mrs. Seymour again dipped her hand into
the box, and drew forth the fragments of a work on Real Property.
“That,” said Mr. Seymour, “is en_tail_; pray, _cut it off_, and give it
to me.”
“We have here,” continued the lady, “the Memoirs of an Italian Bandit.”
“Then prepare him for his fate; I have a noose quite ready for his
reception.”
“Here is a poem, entitled Waterloo.”
“I will patronise it,” said her husband; “and I warrant you that, under
my auspices, the muse will soar to a greater height than she ever could
otherwise have attained.”
“We have here, I declare, a part of * * * * [sic] pamphlet.”
“Then I have lost my wager,” exclaimed Mr. Seymour, “for I defy the
power of man to make either head or _tail_ of it.”
Thus did Mr. and Mrs. Seymour proceed; the one cutting paper, the other
cutting jokes; nor did the former cease stringing puns, until he had
finished stringing the tail.
“I must now conclude by making a knot that shall not be in danger of
becoming untied in the breeze,” said Mr. Seymour: “but stop, stop one
moment! I still require one more piece of paper to complete my task,
and let it be double.”
“Here then is a piece of paper, which, from its texture, appears to be
well adapted to your purpose. Let me see, what is it? I declare it is
the titlepage of an Essay on Matrimony.”
“Capital!” cried her husband; “a strange coincidence, truly; you have,
indeed, furnished me with a knot that cannot be easily untied, however
stiff may be the breeze; hand it over to me, for it will afford a very
legitimate finish, and is generally the conclusion of every _tale_: but
where is the vicar? What, ho! Mr. Twaddleton.”
The reverend gentleman had so contrived to conceal his person in the
corner of the room, behind a large folio which he had placed on a desk
before him, that several moments elapsed before he was discovered; at
length, however, a long-drawn sigh betrayed him in his retreat.
“Upon my word,” exclaimed he, as he pushed aside the huge folio, “your
volatility, Mr. Seymour, is wholly inconsistent with the gravity of a
scientific instructor.”
“But, at present,” replied Mr. Seymour, “I am the manufacturer of a
kite’s tail; and, surely, upon such an occasion, _flightiness_ ought
not to be urged to my disparagement.”
The party, shortly after this discussion, separated: Mr. Seymour
retired to his own room; the vicar proceeded to the church to bury a
patient of Doseall’s; and the children ran into the garden to enjoy
their rural sports.
On the following day, before the wings of the lark had brushed away the
morning dew, Tom and his sisters, buoyant with expectation, had
descended into the garden, in order to ascertain the state of the
weather and the direction of the wind; but the sky was sullen and calm,
not a breath disturbed the susceptible leaves of the aspen; all was
repose--“a dread repose.”
“No kite-day this,” sighed Tom, with a countenance as lowering as the
morning clouds.
“Have patience,” said Louisa; “the wind may yet rise, it is only just
six o’clock.”
Thus did the minds of the children continue to hover between hope and
despair, until after breakfast, when they determined to seek the
gardener, and hold a grave consultation with that acknowledged judge of
the elements; he told them that showers might be expected, but he
thought it probable that the wind might rise after mid-day. “I will,
however,” said he, “consult my oracles;(33) after which, I shall be
able to give you a satisfactory opinion.” So saying, he left them; and,
on his return, observed that “as the _Siberian sow-thistle_ had closed
itself the preceding evening, and the _African marigold_ continued shut
after seven o’clock in the morning, he had thought there would be rain;
but,” he added, “that upon inspecting the _poor-man’s weatherglass_,
the _Anagallis arvensis_, or _red pimpernel_, two hours ago, he had
found it open, from which he concluded that the day would have been
fine.”
“There, Louisa; it will be a fine day, after all,” exclaimed her
delighted brother.
“No, indeed,” continued the gardener; “on returning just now to the
flower, which never deceives us, I found it had closed itself, so that
rain is inevitable.”
Nor was this opinion erroneous; for before the brother and sister could
reach the lodge, the heavy clouds began to discharge their watery
burthen, and the rain continued in one incessant shower for more than
two hours; it then gradually abated, and the children, who had been
anxiously watching it at the library window, were suddenly relieved
from their anxiety by the appearance of the vicar, whom they espied
slowly winding his way through the dripping shrubbery.
“‘Heu! quianam tanti cinxerunt æthera nimbi?’
as Virgil has it,” exclaimed the vicar, as he approached the portico,
where Mr. Seymour and his family had assembled to salute him.
“We are under the influence of St. Swithin, vicar,” said Mrs. Seymour,
“and I fear there is but slender hope of its becoming fair.”
“Psha! who cares for St. Swithin?(34) My barometer is rising rapidly,
and I place more confidence in that classical deity, Mercury, than in a
saint of so very questionable a character.”
At this moment, Phœbus, as if delighted by the compliment thus bestowed
upon his heathen brother, cast a sly glance from behind a dark cloud,
and illumined the spot upon which the vicar was standing. In short,
after the lapse of half an hour, the sun broke through the gloom, and a
brisk gale followed; the countenances of the children sympathised with
the face of the heavens, and the expression of hope lighted them up, in
proportion as the sun illumined the departing clouds with its radiance.
“It is now quite fair, papa,” cried Tom, in a voice of triumph, “and
there is a most delightful wind; shall we not proceed at once to the
common?”
“Presently,” answered his father: “the ground is yet extremely wet.”
In the course of an hour this objection had been removed, and the party
prepared to set off on their kite-flying expedition.
“Bring me the kite, and let me sling it properly over Tom’s shoulder,”
said Mr. Seymour.
“I will carry the string,” exclaimed Louisa; “how nicely it is wound
round the stick.”
As the party walked forwards, the vicar asked Tom whether he knew from
whence the name of the _kite_ originated.
“A kite is a bird of prey,” answered the boy, “which soars a great
height; and from remaining stationary in the air, was, I suppose,
thought to resemble the paper kite.”
“That is a very good explanation,” said the vicar; “or it may, perhaps,
have derived its name from the circumstance of its having been
originally constructed in the shape of a bird of this description. In
China the flying of kites is much more practised than in this country;
and I understand that their shape is always that of some bird.”
“In the London toy-shops you may constantly meet with them in such
forms, as well as in many other fantastic shapes,” observed Mr.
Seymour; “and,” continued he, “I remember to have seen, some years ago,
a kite which resembled a man. It was made of linen cloth, cut, and
painted for the purpose, and stretched on a light frame, so constructed
as to resemble the outline of the human figure. It stood upright, and
was dressed in a sort of jacket. Its arms were disposed like handles on
each side of its body, and its head being covered with a cap,
terminating in an angle, favoured the ascent of the machine, which was
twelve feet in height; but to render it easier to be transported, it
could be folded double, by means of hinges adapted to the frame. The
person who directed this kind of kite was able to raise it, though the
weather was calm, to the height of nearly five hundred feet; and, when
once raised, he maintained it in the air by giving only a slight motion
to the string. The figure, by these means, acquired a kind of
libration, like that of a man skaiting on the ice. The illusion,
occasioned by this spectacle, did not fail, as you may readily suppose,
to attract a great number of spectators.”
“I believe, however,” observed the vicar, “that the figure commonly
adopted, is the one best calculated for the purpose.”
“Undoubtedly,” replied Mr. Seymour, “and for obvious reasons; the
curvature of the bow enables it to escape the resistance of the air, as
it rises; which, after having struck it, slides off, just as the
current is more effectually turned aside by the gently curved prow,
than by that which has a sharp outline; for the same reason, the mast
of a ship, though it has a conical shape, is more easily drawn through
the water with its broad, than with its narrow end, foremost; for
although the primary obstruction is, no doubt, greater in the former
case, yet the water heaped, as it were, on the front, is made to stream
off with a slight divergency, and therefore does not hang on the sides
of the mast, as it would in the latter case. This shape of the kite,
moreover, presents the largest surface at the point upon which the wind
can act with the greatest effect, while the whole is lightened by the
removal of parts that would obstruct its action. The tail has also a
greater control over a figure of such a description.”
Mr. Seymour asked the vicar, “whether he could explain the origin of
the French term for the kite, viz. _cerf volant_, or flying stag; I
never can believe,” continued he, “that the kite could ever have been
constructed in the shape of that animal.”
“I am unable to clear up the difficulty,” replied the vicar; “and yet I
have taken some pains upon the subject. The earliest notice of the
kite, which I have been able to discover, is in a short English and
French Dictionary, by Miege, which was published in the year 1690, and
it is there described under the name of _cerf volant_.”
“I wonder,” cried Tom, “who invented the kite?”
“In, that, again,” answered Mr. Twaddleton, “I am unable to furnish you
with any satisfactory information. The pastime appears to be of very
ancient date in China, and was, probably, first imported into Europe
from that country.”
“At what period, do you suppose?”
“Strutt, who was very assiduous and correct in all his antiquarian
researches, was of opinion that its introduction into England could not
be dated farther back than a hundred and fifty years.”
The party had, by this time, reached Overton heath; the weather was
favourable; and the kite impatiently fluttered in the breeze, while Tom
was eagerly engaged in unwinding its streaming tail, and preparing the
paper machine for ascent.
“Is the string fixed to the belly-band?” asked Mr. Seymour.
“All is ready,” replied the vicar; “and I will hold it up, while Tom
runs with it against the wind. Had King Eric set his cap for us, we
could not have had a more favourable breeze.”
“There is not the least occasion to raise the kite from the ground,”
observed Mr. Seymour; “let its point rest on the grass, and place its
tail in a straight line in front of it; I warrant you it will rise, as
soon as Tom begins to run.”
Tom immediately set off, and the kite rose majestically into the air.
“Give it string--give it string--gently, gently--now stop; there is no
occasion for your running any farther but let out the cord, as long as
the kite carries it off vigorously, and keeps it fully stretched; but
wind it up the moment its tension is relaxed.”
“It is rising very fast,” cried the breathless boy, “but the string
burns my hand as it passes through it; I shall not be able to endure
the heat.”
“Be patient, and let it pass more slowly; put on your glove,” said his
father.
“Ay, ay; put on your glove,” repeated the vicar; “even Xenophon
himself, who declaimed so warmly against the effeminacy of the
Persians, for wearing gloves, would scarcely have refused his consent
to their use on such an occasion.”
“What is it that produces so much heat?” enquired Louisa.
“The friction of the string,” replied her father.
“Do you not know that carriages frequently catch fire from the friction
of their wheels, unless it be prevented by the application of grease?”
“Yes,” said Tom; “and I have heard that the natives of some countries
kindle their fires by rubbing pieces of wood together.”
“The original inhabitants of the new world,” observed his father,
“throughout the whole extent from Patagonia to Greenland, procured fire
by rubbing pieces of hard and dry wood against each other, until they
emitted sparks, or burst into flame; some of the people to the north of
California produced the same effect by inserting a kind of pivot in the
hole of a very thick plank, and causing it to revolve with extreme
rapidity: the same principle will explain how immense forests can have
been consumed; for it is evident, that the violent friction of the
branches against each other, from the agitation of the wind, would be
fully adequate to the production of such an effect.”
“You have also an excellent example of the effect of friction in
producing heat,” said the vicar, “in the history of the whale fishery;
for, in harpooning the fish, unless the sailors observe the greatest
caution in letting out the rope, its friction upon the side of their
boat will be sure to set it on fire.”
“And how do they manage it?” asked Louisa.
“As soon as the whale dives,(35) after having been wounded, it draws
out the line or cord of the harpoon, which is coiled up in the boat,
with very considerable velocity. In order, therefore, to prevent any
accident from the violence of this motion, one man is stationed with an
axe to cut it asunder, if it should become entangled; while another,
with a mop, is constantly cooling with water the channel through which
it passes.”
“The kite is now at a considerable height,” observed Tom; “but look at
the string, how bent it is! I have repeatedly endeavoured to pull it
straight, but without success.”
“How could you have expected to succeed in the attempt? Consider the
weight of such a long line of string.”
“Then it is not the pressure of the atmosphere which gives it that
curved form?”
“Assuredly not: have you so soon forgotten that the air presses equally
in all directions, and would therefore tend to straighten, as much as
to give a curved direction to the string? But, as you now appear to
have let out the whole of your string, suppose you allow the kite to
enjoy its airing, while we proceed to consider the philosophy of its
ascent, and the nature and direction of those forces by which it is
effected.”
“The kite pulls so amazingly hard,” cried Tom, “that unless I fix the
string securely around the tree, we shall run the chance of losing it.”
“I am well aware of the force it exerts,” replied his father. “Dr.
Franklin has said, that, with a good kite, a man unable to swim might
be sustained in the water, so as to pass from Dover to Calais; but I
agree with him in thinking, that a packet would be a much safer, as
well as a pleasanter mode of conveyance.”
“Now, then, for your explanation of the kite’s ascent. Unless I am
mistaken, you will find the subject much more complicated than you
imagine,” said the vicar.
“Not at all; Tom, who, I trust, has a perfect acquaintance with the
composition and resolution of forces, will very readily understand the
explanation I propose to offer. I admit, however, that there are some
few points in the enquiry, which cannot be successfully treated without
a knowledge of the higher branches of the mathematics; but I shall, of
course, avoid all such difficulties.[42] Can you tell me, Tom, what
advantage is gained by your running with the kite?” asked Mr. Seymour.
“I suppose that you thus obtain more force from the wind.”
“Certainly: action and reaction are equal. By running, therefore, with
your kite against the wind, you strike the air, and thus produce a
reaction, which is equal to the force of the blow given to it. When the
wind is high, and its action is not intercepted by surrounding objects,
there cannot exist any necessity for such an expedient.”
“The principle is the same as that which enables the bird to rise into
the air by flapping its wings,” observed the vicar.
“Unquestionably,” replied Mr. Seymour.
“Does the kite, then, rise in the air, from the same causes that enable
a bird to fly?” asked Tom.
“We are not, at present, considering the ascent of the kite, but the
advantage which is obtained by running with it: this latter, as the
vicar has properly observed, undoubtedly depends upon the same
principle as that which enables the bird to rise, by the motion of its
wings, and which constitutes the third law of motion,[43] viz. that
_action and reaction are equal_; that is to say, whenever one body
exerts a force upon another, the second body opposes the first, with
equal force, in an opposite direction. If, then, the bird strikes the
air below it with a force which is equal to its weight, then must there
be a reaction of the air, upwards, exactly equal to it; and the bird,
being acted upon by two equal forces, in opposite directions, will,
necessarily, rest between them.”
“That is clear enough; but the bird _rises_,” answered Tom.
“Because the force of the stroke is _greater_ than the weight of the
bird, and it therefore rises with the _difference_ of these two forces;
were the stroke _less_ than its weight, then would it sink with the
difference. Suppose, for example, a bird weighs _twelve_ ounces, and it
strikes the air with a force equal to _sixteen_, is it not clear that
it must rise with a force equal to _four_? and is it not evident that,
if it strikes the air with a force equal only to _eight_, that it must
sink with a force equal to _four_?”
“So far I understand it perfectly; but I was thinking that, as the wing
flaps up and down, what was gained by striking the air downwards must
be counterbalanced when the bird raised her wing again, and thus struck
the air in the contrary direction,” observed Tom.
“I give you no small degree of credit for that remark,” said his
father; “for it is undoubtedly true that, if the flapping of the wings
in flight were no more than the motion of the same surface upwards and
downwards, the bird must lose as much by one motion as she could gain
by the other; the skylark could never ascend by such an action, for, as
you have so justly remarked, although the stroke upon the air by the
under side of her wing would carry her up, the stroke from the upper
side, when she raised her wing again, would bring her down; but, if you
will attentively examine the structure of the wing, you will at once
perceive, from its external convexity, the disposition, and more
particularly the overlapping of its larger feathers, that when the wing
is drawn up, its surface is contracted, and when let down fully
expanded--or, in other words, that the feathers strike the air
downwards with their flat side, but rise from the stroke slantwise,
just as the rower in a boat, after having given the stroke, turns his
oar so as only to present its edge, an operation which is termed
_feathering_, from its resemblance to this very action of the wing in
flight.”
“It appears to me that flying is an easy process,” said Tom; “could we
not contrive some sort of flapper, by which we might be able to rise
into the air?”
“Your opinion, my dear boy, is by no means singular; hundreds have
entertained the same belief before you; and so confident was the famous
Bishop Wilkins, that he declared it to be his conviction, that, in
future ages, it will be as usual to hear a man call for his wings, as
it is now to call for his boots.”
“Yes,” said the vicar; “and if my memory is correct, William of
Malmesbury, in his account of the Conquest of England by the Normans,
mentions a Benedictine monk, by the name of Elmer, who having affixed
wings to his hands and feet, ascended a lofty tower whence he took his
flight, but he fell to the ground and broke both his legs.”
“I do not see the difficulty,” exclaimed Tom.
“The weight of our bodies is so great, that we have not sufficient
muscular strength to impart a blow to the air that shall be equal to
it. Now are you satisfied?” said his father.
“I am perfectly satisfied, if that be the case, that we can never hope
to fly.”
“The principle, however, which I have just explained,” observed Mr.
Seymour, “although it will fail us in our attempts to construct wings,
is nevertheless extensively applicable in mechanics. A vane or fly, for
instance, by resisting the air as it spins round, becomes the regulator
of machinery. The intervals between the strokes on the bell of a clock
are thus regulated, and the fly, on this occasion, is so contrived that
this interval may be altered, or the clock made to strike faster or
slower, by presenting the arms of it more or less obliquely to the
direction in which they move. The same kind of fly is the regulator
used in musical boxes, as I will presently show you, and indeed in
almost all mechanical toys. Let us now return to the subject of the
kite; for, as yet, we have merely considered the effect of increasing
the wind upon its surface; we have next to enquire how the wind
operates in raising it into the air.--Do you not remember, when I
adjusted the noose in the belly-band, I stated that much depended upon
this part of the apparatus? You will, at once, perceive that it will
influence the angle which the kite forms with the earth, and I am about
to prove to you, that the theory of the kite’s ascent is materially
connected with the value of this angle; but, in order to render my
explanation intelligible, I have prepared a diagram, to which I am
desirous of directing your attention.
[Illustration: Diagram of a kite labeled with A, B, O, S, T, W, and Y.]
“The kite here appears in the act of rising from the ground; the line W
will represent the direction of the wind blowing upon it, all the
currents of which we will suppose united in one; it is evident, from
what has been already stated, that as it falls upon an oblique surface,
it will be resolved into two forces, viz. into one parallel with it,
and into another perpendicular to that surface; of which the force
represented by the line Y will alone produce any effect, carrying the
kite along the line O A, or in a direction parallel to itself; and you
must have observed that this was the direction in which the kite was
impelled, when you suffered it to rise, without checking its progress
by the string.”
“I remember that well,” said Tom; “and I also observed that, when I
pulled my string, the kite immediately rose more perpendicularly.”
“To be sure it did; because, by that operation, you called a new force
into action; which I have represented in the diagram by the line S T.
The kite was therefore under the influence of the two forces O A and
S T, and, since these are in the direction of the two sides of a
parallelogram, it would not obey either, but ascend through O B, its
diagonal.”
“Notwithstanding Mr. Twaddleton’s doubts upon the subject,” said Tom,
“I am sure that I perfectly understand your explanation; and I think I
may also answer for my sister: but you have not yet told us any thing
about the tail; I suppose, however, that it acts like the rudder of a
ship, or the tail of a bird.”
“Before I answer that question, let me inform you how the tail of a
bird differs, in its action and uses, from the rudder of a ship. In the
first place, the rudder is so fixed that it can but move in one
horizontal plane, and can therefore only turn the vessel to the right
or left, which, indeed, is all that is required;(36) but the tail of
the bird, in addition to this motion, can be placed in a diagonal
direction, and when expanded will offer a considerable surface to the
air, so as to fulfil some of the offices of a third wing. Have you
never watched the manœuvres of the rook, as he gambols through the air?
After flying in the ordinary way, you will observe his wings at rest,
and that he glides along apparently without the least exertion in his
descent. In this case, his expanded wings act as a parachute; then,
again, you will observe him wheeling round, a manœuvre which is partly
produced by the oblique position of his tail, and which is readily
explained upon the principle of the resolution of forces I have just
described with reference to the action of the wind upon the surface of
the kite.(37) I ought also to state, that the tail serves to poise the
body of the bird.”
“Does the bird, then, never use its wings for the purpose of directing
its course?” asked Louisa.
“Undoubtedly it does,” answered her father; “the tail is only to be
considered as a supplementary organ: it is by means of the wings that
it generally directs its course, for it is evident, that it can easily
turn, either to the right or left, by flapping the opposite wing with
increased force, just as a boat is turned about to the right, by a
brisk application of the left oar. In like manner the irregular flight
of the butterfly, now up and now down, now to the right and now to the
left, is no doubt effected by the wings striking the air one after the
other, or perhaps with an alternate and unequal force. The object of
such an action is obviously to baffle the pursuit of birds which fly in
a right line, whereas you see the butterfly does just the contrary.”(38)
“How very wonderful,” said Louisa, “is the action of the wings of
insects. I have often watched them during their flight, and their
rapidity is such as to surpass the power of vision.”
“I shall have occasion to advert to that subject hereafter,” said Mr.
Seymour; “at present, I shall only observe, that a gnat’s wing, in its
ordinary flight, beats many hundred times in a second.”
“But you have not yet answered Tom’s question,” said the vicar. “Of
what use is the tail of the kite? Does it assist its ascent, or is it
merely an appendage of ornament?”
“In the first place, it keeps the head of the kite to the wind; and in
the next, it lowers its centre of gravity, and throws it towards its
extremity, which not only prevents the chance of the machine being
upset in the air, but so poises and regulates the position of the kite
as to maintain the angle which it is necessary for the string to make
with the surface.”
Mr. Twaddleton here enquired what might be the most advantageous angle
for the kite to form with the horizon, in order that the paper machine
should rise to the greatest altitude.
“If the wind be horizontal,” answered Mr. Seymour, “it is evident that
the inclination of the kite’s surface ought to be the same as that
which the rudder of a ship should make with the keel, in order that the
vessel may be turned with the greatest facility; supposing the currents
of water, which impel it, to have a direction parallel to the keel.”
“And what ought that angle to be?” enquired the vicar.
“_Fifty-four_ degrees, and _forty-four_ minutes,” replied Mr. Seymour;
“and let me here remark,” continued he, “as we have already considered
the philosophy of the flight of a bird, that its pinions are so set
upon the body as to bring down the wings in an _oblique_ direction
towards the tail; so that in their action upon the air, we have the
same resolution of forces as in that of the wind upon the surface of
the kite, by which the body of the bird is not only supported, or
raised perpendicularly, but carried forward.”(39)
Tom here interrupted the dialogue, by expressing a regret that he
should have been provided with so small a quantity of cord.
“I do not believe, my dear boy, that any advantage could be gained by
an additional quantity of string,” said his father.
“Is there, then, any reason why the kite should not ascend, even above
the clouds, provided that my string were sufficiently long and strong?”
“Yes; indeed is there a most unanswerable reason. Remember that the
kite is made to rise by the operation of two forces; the one afforded
by the wind, the other by the action of the string; now it is quite
evident that, when the weight of the string, added to that of the kite
itself, becomes equal to the force of the wind, acting upon the surface
of the machine, a general balance, or equilibrium, of forces will be
established, and the kite can no longer continue to ascend.”
“Will it, then, remain stationary under these circumstances?” asked
Louisa.
“It must do so, unless the force of the wind should abate; for it is a
proposition in mechanics, which I shall hereafter endeavour to
demonstrate(40), that, if a body be acted upon by three forces, which
are proportional to, and in the direction of, the three sides of a
triangle, it will be kept at rest. The kite is exactly in this
predicament, for its weight, the force of the wind, and the action of
the string, fulfil these conditions, and consequently keep the kite
stationary.”
“Then I must give up my intention of trying to raise the kite above the
clouds,” said Tom.
“Although you may not be able to raise any single kite to the altitude
you may desire, it is easy to accomplish your plan by a series of
kites; the string of the first being attached to the back of the
second, and so on.”
“How, papa? I do not exactly understand you.”
“Your kite,” said Mr. Seymour, “is now as high in the air, as the force
of the wind is capable of raising it; suppose you were to fix the end
of the string you hold in your hand to the back of another kite, would
not this second kite ascend as high as your first, by the same force,
and your first kite therefore rise to double the altitude it is at
present. In like manner you might attach a third kite, and so on.”
“Now I comprehend it; and I should much like to try the experiment,”
said Tom.
“You shall certainly witness the effect I have described; but you must
provide yourself with some stout string, for the force which the kites
exert when thus arranged, is greater than you can easily imagine;
indeed I question whether you would be able to hold them,” observed his
father.
Mr. Twaddleton here informed the young party that he had himself
witnessed a carriage containing three persons that had been drawn along
the road by kites, at the rates from fifteen to twenty miles an hour.
“I have seen the account of it,” said Mr. Seymour, “and if I remember
right, the principal kite was preceded at the distance of about 120
feet by a smaller pilot one, which served to direct it away from any
obstacles, such as trees, houses, &c. with which it might otherwise
have come in contact.”
“But how was the pilot kite made obedient to the will of the driver?”
asked Louisa.
“By means of strings so attached to it that its surface was easily made
to alter its angular position,” answered Mr. Seymour.
“If my twine should snap,” said Tom, whose attention was suddenly drawn
to his kite from a slight unsteadiness in its motion, arising from a
gust of wind, “we could easily recover it, that is one good thing; for
it is hovering over the open field at the end of the heath.”
“If you imagine that the kite, under such circumstances, would fall
upon the spot directly under it, you are much deceived: recollect that,
if the string should snap, the kite would be abandoned to two forces,
those of the wind, and its own gravity; and you will perceive that,
under such circumstances, it could not obey either of them, but would
fall in an intermediate or diagonal direction. This fact will be
rendered apparent by the annexed diagram. B A may be supposed to
represent the force and direction of the wind acting upon the kite, and
B D those of its gravity; then it is evident that, under the influence
of these joint forces, it would describe the diagonal, and, for reasons
already explained, that line must necessarily be the _curve_ B F.”
[Illustration: Diagram showing arc of fall trajectory.]
“Come,” said the vicar, “before Tom draws down his kite, let us send up
a _messenger_.”
“What may that be?” asked Louisa.
“A piece of paper or pasteboard, which, on being introduced upon the
string, is blown along the line up to the kite.”
The _messenger_ was accordingly prepared, and being placed upon the
string, it ascended as Mr. Seymour had anticipated. While this
operation was in progress, the vicar stood earnestly gazing upon the
kite, and, at length, burst forth in the following animated soliloquy:--
“Assuredly, this must be acknowledged as a most beautiful and imposing
toy! Fastidious or insensible must be that person, who does not feel
exhilarated as he gazes on the kite, proudly floating under the canopy
of heaven, and reflecting the departing smiles of the evening sun,
after it has ceased to cheer us below.”
“It has been said,” observed Mr. Seymour, “to the disparagement of
kite-flying, that as soon as the machine has been raised into the air,
and all the string let out, the excitement of the sport is at an end,
and that as nothing further can be achieved, the interest of the
performer from that moment begins to languish; now at this period the
_messenger_ will open a new source of pleasure and instruction, and
may, by a little ingenuity, be made to afford a great diversity of
amusement. I have therefore provided myself with several varieties of
this machine. Here is one in the form of a dragon, which, as it
ascends, produces a very striking and almost magical effect. See, there
it goes!”
The children were delighted, for the string upon which it was carried
became at a certain height invisible; so that the figure appeared like
a monster hovering in the air.
“I will now show you a _winged_ variety of this apparatus, which we
will name the _Brompton Messenger_.[44] It consists of a hollow
cylinder of stiff pasteboard, or thin wood, the diameter of which is
sufficiently large to allow its free revolution round the string of the
kite. To this cylinder are attached several flappers, or sails, in an
oblique direction, like those of a windmill, each of which is covered
with paper of a different colour. The action of the wind upon those
oblique surfaces necessarily occasions a rapid rotation, upon a
principle which I shall presently explain; and the beautiful effect
thus produced, as the whirling body ascends, must be seen before it can
be appreciated. I have some other contrivances of a similar nature,
which it is my intention to prepare for your future amusement.”(41)
“Has the kite ever been applied to any useful purposes?” asked Tom.
“Certainly,” answered his father. “It was by means of the kite that Dr.
Franklin was enabled to demonstrate the identity of electricity and the
cause of lightning, and thus to disclose one of the most awful
mysteries of nature.”
“Pray do tell us something about this electrical kite, papa,” said
Louisa.
“Not at present, my love; it would divert us too much from the subjects
in which we are engaged: at some future period I shall have much
pleasure in introducing you into these fairy regions of philosophy.”
“I just now remember reading in Miss Edgeworth’s Harry and Lucy,” said
Louisa, “something about a kite and Pompey’s pillar.”
“I am glad that you have reminded me of that story,” replied Mr.
Seymour: “I will relate it to you. Some English sailors laid a wager,
that they would drink a bowl of punch on the summit of Pompey’s pillar.
Now, that pillar is almost a hundred feet high, and it is quite smooth,
so that there was no way of climbing to the top, even for sailors, who
are such experienced climbers: so they flew their kite exactly over the
pillar, and when it came down on the opposite side, the string lay
across the top of the capital. By means of this string, they pulled a
small rope over, and by this a larger one, that was able to bear the
weight of a man; a pulley was then fastened to the end of the large
rope, and drawn close up to the upper edge of the capital; and then,
you perceive, they could easily hoist each other up. They did more, for
they hoisted the English flag on the top, and then drank the bowl of
punch, and won their wager.”
“That is a very good story,” said the vicar; “but I cannot help
regretting that so much ingenuity and labour should not have had a
nobler end to accomplish.”
“There is some truth in that observation,” said Mr. Seymour, “and I
will, therefore, relate another story which shall be more congenial to
your heart, and in which the kite will present itself in a more
interesting point of view; for, instead of enabling the sailors to
drink a bowl of punch at an altitude otherwise inaccessible, we shall
find it engaged in rescuing them from the horrors of shipwreck.”[45]
“Pray proceed, papa.”
“No, my dear, upon reflection, I think it will be better that we should
postpone the story, until your return to the lodge, when you shall read
it in ‘Harry and Lucy.’ I will also point out to you, in the same work,
an account of a new and useful application of the messenger, which will
prove to you how successfully the faculties of youth may be increased
and improved by those very amusements which are too generally regarded
as idle and unprofitable: I shall at the same time exhibit one or two
experiments in illustration of the nature and causes of wind.”
“Shall we not return immediately?”
“No, my dear; it would not be in my power to attend you at present; but
join me in the library after dinner; Mr. Twaddleton will now accompany
me to the village, and do you remain and enjoy the amusement of your
kite.”
It was not until the evening, that Tom and his sisters requested their
father to fulfil the promises he had made them in the morning.
“You told us,” said Louisa, “that you would give us some information
about the wind; the subject has been puzzling me ever since, for I
cannot make out the cause of it.”
“Wind, my love, is nothing more than air in motion; and is produced by
a large volume of it flowing in a current, or stream, from one place,
or region, to another, and with different velocities.”
“And what can produce these currents?” asked Tom.
“After the explanation of the action of the pump, I do not think that I
shall have much difficulty in making you understand the nature of the
operations by which wind is occasioned. Suppose a partial vacuum should
be formed in any region, would not the neighbouring air immediately
rush in to supply the deficiency and restore the balance?”
“Undoubtedly; from the pressure of the air behind it.”
“Heat,” continued Mr. Seymour, “will produce a partial vacuum, by
rarefying the air, and thus rendering it lighter; in consequence of
which, it will ascend, and the colder air will rush in to supply its
place.”
“I do not exactly see why the rarefied air should ascend,” observed
Louisa. “It appears to offer an exception to the general law of
gravity.”
“Not at all; on the contrary, its ascent is occasioned by the force of
gravity: in the first place, however, to prove the fact that heated air
does actually ascend, we have only to observe the direction of smoke,
as it issues from the chimney; this consists of minute particles of
fuel carried up, by a current of heated air, from the fire below; and
as soon as this current is cooled by mixing with that of the
atmosphere, the minute particles of coal fall, and produce the small
black flakes which render the air, and every thing in contact with it,
so dirty in a populous city.”
“But I want to know, papa, what it is which causes the hot air to
ascend?”
“The greater weight of the cold air above it, which gets, as it were,
beneath the lighter air, and obliges it to rise; just in the same way
as a piece of cork, at the bottom of an empty vessel, is made to rise
to the surface of the water which may be poured into it.”
“Now I understand it; pray, therefore, proceed with your account of the
wind. You have just said that heat rarefies the air, and causes it to
ascend.”
“And thus produces a current of air, or a _wind_.”
“Is heat, then, the cause of wind, papa?” asked Tom.
“It is one great cause; but there are, probably, several others; I
will, however, exemplify this subject by an experiment.”
So saying, Mr. Seymour produced a water-plate, a large dish, and a jug
filled with cold water. The bell was rung, and the servant entered with
a tea-kettle of boiling water.
The large dish was then filled with the cold, and the water-plate with
the boiling fluid.
“Let this large dish represent the ocean,” said Mr. Seymour, “and this
water-plate, which I will now place in its centre, an island in that
ocean; for the land, from receiving the rays of the sun, will be more
heated than the water, and will consequently rarefy the air above
it.--Now, Tom, light me the wax taper.”
“I have done so.”
“Then now blow it out.”
“I cannot imagine what you are about, papa;--‘Light the candle, and
then blow it out!’--but it still smokes, shall I put the extinguisher
over it?”
“By no means; give it to me, and observe what will happen when I carry
it round the edge of the dish.”
“The smoke goes to the centre,” exclaimed Tom.
“Showing, thereby, the existence of a current towards the water-plate,
or island; in consequence of the air above it having been heated, and
therefore rarefied. This explains in a very satisfactory manner, a fact
which may be constantly observed in our own climate, viz. a gentle
breeze blowing from the sea to the land in the heat of the day. Upon
the same principle it is, that most of the winds in different parts of
the globe may be readily accounted for.”(42)
“I suppose,” said Tom, “that the air must rush with great velocity, in
order to produce wind.”
“A very general error prevails upon this subject,” replied his father;
“the rate of motion has been greatly exaggerated. In a brisk gale,
even, the wind does not travel with such velocity, but that it may be
easily traced by the eye; and the sailor is able to watch its progress
by the ripple which it produces on the sea.”
“Has, then, the rate of its motion ever been estimated?” asked Louisa.
“When its velocity is about two miles per hour, it is only just
perceptible. In a high wind, the air travels thirty or forty miles in
the same period. In a storm, its rate has been computed as being from
sixty to eighty miles. It has also been ascertained, by experiment,
that the air, as it rushes from a pair of blacksmith’s bellows, has not
a velocity above that of five and forty miles in the hour.”
“At what rate should you think the air travelled this morning, when we
flew our kite?” enquired Louisa.
“I should think at about five miles an hour, for it was a pleasant but
gentle breeze.”
-----
Footnote 41:
The author has been thus minute, in order to afford his young friends
clear directions for constructing a kite, and which, as far as he
knows, are not to be found in any work hitherto published; and he
will also avail himself of this opportunity to state, that the thin
glazed linen of various colours, commonly known to haberdashers by
the name of lining, has been found to be the best material as a
covering for the kite. It is not only more durable than paper,
defying the most boisterous wind, but superior to it as being secure
from the effects of a shower of rain.
Footnote 42:
Those readers, who are inclined to enter more deeply into the
subject, may consult, with advantage, a memoir on the kite, by Euler,
published in the Transactions of the Academy of Berlin for the year
1756.
Footnote 43:
See p. 60.
Footnote 44:
From associations of an interesting nature connected with the
residence of the author’s children.
Footnote 45:
Transactions of the Society for the Encouragement of Arts, vol. xli.;
and Miss Edgeworth’s Harry and Lucy, vol. iv. p. 288.
------------------------------------------------------------------------
[Illustration: Children playing with paddles and a shuttlecock.]
CHAPTER XIV.
_A short discourse.--The Shuttlecock.--The solution of two problems
connected with its flight.--The Windmill.--The Smoke-jack.--A
toy constructed on the same principle.--The Bow and
Arrow.--Archery.--The arrival of Isabella Villers._
Mr. Twaddleton, on his arrival at the lodge, on the following morning,
was informed that Miss Villers was expected at Overton in the evening.
“Your account of that young lady,” observed the vicar, “has greatly
prepossessed me in her favour; I only hope that she is not too _blue_.”
“I care not how blue the stockings of a lady may be,” said Mr. Seymour,
“‘provided her petticoats be long enough to hide them;’ and from my
knowledge of Miss Villers, I can assure you, exalted as are her
attainments, they are so veiled by feminine delicacy and reserve, that
they may insidiously win, but will never extort our homage.”
“Ay, ay,” exclaimed the vicar; “I perfectly agree with you in your idea
of feminine perfection--short tongues and long petticoats, Mr.
Seymour.--But where are my little playmates?”
“I left Tom and Fanny on the terrace, a short time since,” replied Mr.
Seymour, “very busily engaged in the game of shuttlecock and
battledoor.”
“The shuttlecock is an ancient sport,” observed Mr. Twaddleton. “It is
represented in a manuscript as far back as the fourteenth century: and
it became a fashionable game amongst grown persons in the reign of
James the First.”
“It is a very healthy pastime,” said Mr. Seymour, “and, in my opinion,
is admirably calculated for females; for, it expands the chest, while
it creates a graceful pliancy of the limbs.”
“I entirely agree with you; it is the only game with which I am
acquainted, in which muscular exercise is gained without compromising
gracefulness. But see, here come the two young rogues.”
“Papa,” exclaimed Tom, “I have been considering whether there is any
philosophy in the game of shuttlecock.”
“There are two circumstances connected with its flight,” replied his
father, “which certainly will admit of explanation upon scientific
principles; and I should much like to hear whether you can apply them
for that purpose. The first is its spinning motion in the air; the
second, the regularity with which its base of cork always presents
itself to the battledoor; so that, after you have struck it, it turns
round, and arrives at your sister’s battledoor in a position to be
again struck by her, and sent back to you.”
“I perfectly understand what you mean; but I really am not able to
explain the motions to which you allude,” said Tom.
“The revolution of the shuttlecock, about its axis, entirely depends
upon the impulse of the wind on the oblique surfaces of its feathers;
so that it is often necessary to trim the feathers of a new
shuttlecock, before it will spin.”
“I understand you, papa; the force of the wind, by striking the oblique
feathers, is resolved into a perpendicular and parallel force, as you
explained to us, when we considered the action of the wind upon the
kite.”
“Exactly; every oblique direction of a motion is the diagonal of a
parallelogram, whose perpendicular and parallel directions are the two
sides. Having settled this point, let us consider the second; viz. how
it happens that the cork of the shuttlecock always presents itself to
the battledoor.”
“I should think,” said Tom, “that the cork points to the battledoor for
the same reason that the weathercock always points to the wind.”
“Admirably illustrated!” exclaimed his father; “the cork will always go
foremost; because the air must exert a greater force over the lighter
feathers, and therefore retard their progress. While we are upon this
subject, I will introduce to your notice some contrivances which are
indebted to this same principle for their operation. In the first
place, there is the arrow; can you tell me, Louisa, the use of the
feathers which are placed round its extremity?”
“To make its head proceed foremost in the air, by rendering its other
end lighter, and therefore more sensible to the resistance of the air,”
replied Louisa.
“Very well answered; that is, unquestionably, one of the objects of the
wings of an arrow; but there is also another, that of _rifling_ it, or
steadying its progressive motion, by causing it to revolve around its
axis. If you will look at this arrow, you will perceive that the
feathers are placed nearly, but not quite, in planes passing through
it; if the feathers were exactly in this plane, the air could not
strike against their surfaces when the arrow is in motion: but, since
they are not perfectly straight, but always a little aslant, the air
necessarily strikes them, as the arrow moves forward; by which force
the feathers are turned round, and with them the arrow or reed; so that
a motion is generated about its axis; and its velocity will increase
with the obliquity of the feathers. You will therefore observe that, in
order to enable the feathers to offer a necessary resistance to the
air, they must possess a certain degree of stiffness or inflexibility.
It was on this account that Roger Ascham,[46] and other skilful artists
in the days of archery, preferred the feathers of a goose of two or
three years old, especially such as drop of themselves, for pluming the
arrow; and the importance, as well as the theory of this choice, is
confirmed by a curious observation of Gervase Markham,[47] who says
that ‘the peacock feather was sometimes used at the short butt; yet,
seldom or ever, _did it keep the shaft either right or level_!’”(43)
“That is intelligible enough,” said Tom, “the feather of the peacock
must have been so flexible as to have yielded to the slightest breath
of air; and now, as we are upon the subject of the arrow, do explain to
us the action of the bow.”
“I shall readily comply with your request, before we part; but I am
desirous, at present, of following up the subject before us, and of
taking into consideration some other instruments which owe their
motions to the action of the air upon oblique surfaces.”
“Suppose,” said the vicar, “you explain to them the action of the wind
upon the sails of the mill.”
“I should like to hear something about the windmill,” observed Tom;
“and, perhaps, Mr. Twaddleton can tell us who invented the machine.”
“The invention is not of very remote date,” replied the vicar.
“According to some authors, windmills were first used in France in the
sixth century; while others maintain that they were brought to Europe
in the time of the crusades, and that they had long been employed in
the East, where the scarcity of water precluded the application of that
powerful agent to machinery.”
“I had intended,” said Mr. Seymour, “to have entered very fully upon
the subject of the windmill; for, although it is a very common machine,
its construction is much more ingenious than is generally imagined; it
must also be allowed to have a degree of perfection, to which few of
the popular engines have yet arrived: but to do ample justice to my
subject, I should require several models which are not yet in
readiness; besides, Tom’s holidays have nearly passed away; I must
therefore postpone the examination of the mill to some future
opportunity, and content myself, at present, with an explanation of its
sails.”
“And let me tell you,” observed the vicar, “that if you succeed in this
one object, you will accomplish a task which has occupied years of
mechanical research. The angle which the surface of the sails ought to
make with their axis, in order that the wind may have the greatest
effect, or the degree of _weathering_, as the millwrights call it, is a
matter of nice enquiry, and has much engaged the thoughts of the
mathematicians.”
“My remarks upon that subject will be very general,” said Mr. Seymour;
“I shall explain the principle, without entering into the minutiæ of
its applications. The vertical windmill, which is the kind in most
common use, consists, as you well know, of an axis, or shaft, placed in
the direction of the wind, and usually inclining a little upwards from
the horizontal line. At one end of this, four long arms, or yards, are
fixed perpendicular to the axis, and across each other at right angles;
these afford a surface, on which a cloth can be spread to receive the
action of the wind. To conceive why these sails should revolve by the
force of the wind, we must have recourse to the theory of compound
motion. It is very evident that, if a mill exposed directly to the wind
should have its four sails perpendicular to the common axis in which
they are fitted, they would receive the wind perpendicularly, an
impulse which could only tend to overturn them; there is a necessity,
therefore, to have them oblique to the common axis, that they may
receive the wind obliquely, when their effort to recede from it causes
them to tarn round with the axis; and the four sails being all made
oblique in the same direction, thus unite their efforts for the common
object.”
“You have not yet told us what degree of obliquity the sail ought to
make with the wind,” said the vicar.
“The same as the kite ought to make, _fifty-four_ degrees and
_forty-four_ minutes,” replied Mr. Seymour.
“Do you not remember, papa, when we were last in London, you pointed
out to us a curious mill on the banks of the river, which went without
any sails?”
“You allude to the horizontal mill at Battersea.”
“I remember it was at Battersea,” observed Louisa; “and I dare say,
papa, that you recollect the strange story which the waterman, who
rowed us down the river, told Tom and myself. He said ‘that, when the
Emperor of Russia was in London, he took a fancy to the neat little
church at Battersea, and determined to carry it off to Russia; and that
for this purpose he had sent a large packing-case; but, as the
inhabitants refused to let the church be carried away, the case
remained on the spot where it was deposited.’”
“It is not a bad story,” said her father; “for the mill certainly, both
in size and figure, may be imagined to resemble a gigantic
packing-case. The mill, of which you are speaking, has been taken down,
in consequence of its use having been superseded by the introduction of
steam. It was erected by Captain Hooper, who also built a similar one
at Margate. It consisted of a circular wheel, having large boards or
vanes fixed parallel to its axis, and arranged at equal distances from
each other. Upon these vanes the wind could act, so as to blow the
wheel round; but had it acted upon the vane at both sides of the wheel,
at once, it is evident that it could not have had any tendency to turn
it round; hence, one side of the wheel was sheltered, while the other
was submitted to the full action of the wind. For this purpose it was
enclosed within a large cylindrical framework, furnished with doors or
shutters, on all sides, to open at pleasure and admit the wind, or to
shut and stop it. If all the shutters on one side were open, whilst all
those on the opposite side were closed, the wind, acting with
undiminished force on the vanes at one side, whilst the opposite vanes
were under shelter, turned the mill round; but whenever the wind
changed, the disposition of the blinds was altered, to admit the wind
to strike upon the vanes of the wheel in the direction of a tangent to
the circle in which they moved.”
“Well; have you any other machine to explain to your scholars?” asked
the vicar; “for,” continued he, “I am anxious to present them with a
bow and arrow which I have provided for their amusement.”
“I will, if you please, first describe to them the mechanism of the
smoke-jack; and I am desirous of doing so, as I have a very pleasing
experiment to exhibit, which is founded upon the same principle.”
Mr. Seymour then described the more common form of this machine. It
consisted, he said, of a number of vanes, of thin sheet-iron, arranged
in a circle, as here represented, but all set obliquely at a proper
angle of inclination. Its action was explained in the following
manner:--When a fire is kindled in the chimney, the air which, by its
rarefaction, immediately tends to ascend, strikes on the surfaces of
the inclined vanes, and by a resolution of forces, similar to that
already explained, causes the spindle, to which they are affixed, to
turn round, and consequently communicates the same motion to the spit.
The brisker the fire becomes, the quicker will the machine move,
because in that case, the air ascends with greater rapidity.
[Illustration: Smoke-jack.]
“I will now exhibit to you a mechanical amusement which is founded on
the same principle,” said Mr. Seymour. “Fetch me the piece of
pasteboard which lies on the library table.”
[Illustration: Simple spiral shape.]
The pasteboard was produced, and Mr. Seymour described upon it a
spiral, similar to that which is represented in the annexed figure. The
spiral was cut out, and extended, by raising the centre above the first
revolution. It was then suspended upon a small spit of iron, which had
been previously prepared; by applying the centre or summit of its
spiral to its point. The whole was now placed on the top of a warm
stove, (the application of a lamp would have answered the same
purpose,) and the machine, to the great delight and astonishment of the
children, soon put itself in motion, and turned without the assistance
of any apparent agent. The agent, however, in this case, was the air,
which being rarefied by the contact of a warm body, ascended, and thus
produced a current. The accompanying sketch may render this experiment
more intelligible to the reader.
[Illustration: “Mechanical amusement” described above.]
The vicar observed that, to him, the experiment was perfectly novel;
although he remembered having seen what he now supposed must have been
a similar contrivance, but which, until that moment, he had always
considered as the effect of clockwork.
“And what might that have been?” asked Mr. Seymour.
“The revolution of a serpent, which I noticed in several windows in
London, during a late illumination.”
“Undoubtedly; it was nothing more than a spiral, so painted as to
resemble that reptile, and which owed its motion to the action of air
heated by a lamp placed beneath it.”
“Now, then,” exclaimed the vicar, “let us direct our attention to the
bow and arrow; see the present I have provided for you, Tom!”
So saying, the worthy clergyman produced a bow and a number of arrows,
together with a target; which, at his desire, had been sent from London.
“I think,” observed Mr. Seymour, “that you should accompany your gift
with some account of archery, or the art and exercise of shooting with
the bow and arrow.”
“That will I readily do,” replied Mr. Twaddleton; who accordingly
proceeded as follows:--
“The bow is the most ancient and universal of all weapons, and has been
found to obtain amongst the most barbarous and remote nations. In the
days of David the practice of the bow would appear to have been so
general, that it was not unfrequently made use of as a figure of
speech. Israel, when blessing his sons, says of Joseph, ‘the _archers_
have sorely grieved him, and shot at him, and hated him; but his _bow_
abode in strength, and the arms of his hands were made strong, by the
hands of the mighty God of Jacob.’”
“Its earliest application was probably for the purpose of obtaining
food,” observed Mr. Seymour.
“Your conjecture has the weight of testimony,” replied the vicar; “when
Isaac sent Esau to the forest, he said, ‘Take, I pray thee, thy
weapons, thy quiver, and thy bow, and go out to the field, and take me
some venison:’[48] and it is even a question, whether the _Saxon_ bow
was ever used by the Anglo-Saxons and Danes for any other purpose than
that of procuring food, or pastime; for the representation of this bow,
in an ancient manuscript[49] of the tenth century, shows it to have
been very differently constructed from what one might expect in a
military weapon; in size, too, it was a mere toy, compared with the bow
of succeeding ages.”
“There can be no doubt that the bow and arrow were employed for the
purpose of killing animals for food from the earliest times; but its
principal interest is derived from its military applications; will you,
therefore, give us a sketch of its history, and confine yourself to its
practice as a warlike instrument in England?”
“And may I also beg of you, my dear sir,” added Mrs. Seymour, “to
explain the different terms which are employed to denote its parts and
applications; such information will be, just now, highly acceptable to
me, as I am reading some romances, in which those terms are constantly
occurring.”
“You shall be obeyed, madam,” replied the vicar, with a courteous smile.
“We are, probably, indebted to the Norman conquest for the introduction
of the bow and arrow as a hostile weapon; but, before I enter upon that
subject, it is necessary to state, that the bows in use in England,
have been of two kinds, the common or _long_ bow, and the _cross_ bow.
The former does not require any description from me, the latter, or
_Arbalet_, as it was called, (from _Arbalesta_, i. e. _arcu-balista_, a
bow with a sling,) consists of a steel bow, fastened upon a stock, and
is discharged by means of a catch, or _trigger_, which probably gave
rise to the lock upon the modern musket.”
“Excuse the interruption,” said Mrs. Seymour, “but do allow me to ask
whether _Arquebusade_ does not derive its name from its having been
formerly applied to wounds inflicted by the cross-bow or _Arbalet_?”
“I thank you, madam; that etymology is entirely new to me, and will
explain the medical name, _Aqua vulneraria_, which has been applied to
that spirit.”
The vicar now proceeded without further interruption.
“The invention of cross-bows is said by ancient writers to have come
from the Sicilians. They were first used in England by the Normans at
the battle of Hastings; and a _quarrel_ or _bar-bolt_ (which is
synonymous with the arrow of the long-bow) was the immediate cause of
Harold’s death. In the reign of Stephen, in 1139, the second council of
Lateran prohibited their use; and some historians assert, that they
were not again used in this country till the reign of Richard I., whose
death, occasioned by one at Chaluz, was considered as a judgment on his
impiety. From the death of Richard till the splendid victories of
Edward III., we hear little of the cross-bow as a military weapon. Its
use appears to have been principally confined to the sieges of
fortified places, and to sea-fights. In 1346, at the battle of Cressy,
a large body of Genoese soldiers, who were particularly expert in its
management, were in the service of the French; but at the commencement
of the action, a sudden shower wetted the strings, and prevented the
archers from doing their usual execution, while the English were still
capable of annoying their enemies by the long-bow with complete
success: both this victory and that of Poictiers, ten years afterwards,
were chiefly ascribed by the English to their archers. In 1403, at the
battle of Shrewsbury, where Hotspur was slain, the archers on both
sides did terrible execution; and the victory of Agincourt, in 1417,
was entirely owing to their skill. Under Edward IV. an ordinance was
made, that every Englishman and Irishman, dwelling in England, should
have a bow of his own height, to be made of yew, wych, hazel, ash, or
any other seasonable tree, according to their power. By Henry VII. and
his son Henry VIII. the use of the cross-bow was entirely forbidden;
and a penalty of ten pounds was to be inflicted on every man in whose
house one might be found. From this time they seem to have been chiefly
used for killing deer.[50] Henry VIII. compelled every father to
provide a long-bow and two arrows for his son at seven years old.
Edward VI., Elizabeth, and James, all encouraged archery: John Lyon,
who founded Harrow school in 1590, two years before his death, drew up
rules for its direction, whereby the amusements of the scholars were
confined to ‘driving a top, tossing a hand-ball, running, and
shooting.’ The last mentioned diversion is in a manner insisted on by
the founder, who requires all parents to furnish their children with
bow-strings, shafts, and tresters, to exercise shooting. A silver arrow
used some years ago to be shot for by the young gentlemen of that
school.”
The vicar concluded, and received the thanks of the party for the
interesting information he had afforded them.
“There is one circumstance connected with the military history of the
long-bow,” said Mrs. Seymour, “which has somewhat surprised me; and
that is, why it should so long have continued in estimation after the
use of gunpowder.”
“That circumstance,” replied her husband, “will cease to astonish you,
when you remember that, until the last century, muskets were very
unwieldy instruments; they were never used without a rest; had no
bayonets, and could not be so frequently discharged as they are at
present.”
“Come,” said the vicar, “I perceive that the children are impatient to
try their skill with their new instrument; let us walk out, and I will
play the Scythian[51] upon this occasion.”
“Now, Tom,” cried Mr. Twaddleton; “we must have an object. Let me see.
Shall it be the ‘_but_,’ ‘_pricke_,’ or ‘_roaver_?’[52] Come, try
whether you can hit yonder gate-post. Take your bow, and here is an
arrow.”
Tom took the bow, and placing the arrow on the string, was about to
draw the latter, when the vicar exclaimed, “Stop--stop--you must pull
back your hand to your right ear, in order to shoot the arrow; whereas
you have placed the bow directly before you, and are about to return
your hand to the right breast.”
“I thought,” said Tom, “that was the proper position; for I remember
reading of the Amazonian women, who are said to have parted with their
right breasts, lest they should prove an impediment to their using the
bow.”
“I do not mean to assert,” replied the vicar, “that there is not ample
classical authority for your proceeding. The Amazons undoubtedly shot
their arrows in such a position; and so, in truth, did the primitive
Grecians; although the ancient Persians drew the arrow to the ear,
according to the fashion of later ages, and which I greatly prefer for
its superior convenience. You may also recollect, as you have been
lately reading ‘The Tales of a Grandfather,’ that the superiority of
the English archers was ascribed to this mode of using their bows; the
words of Sir W. Scott, if I rightly recollect, are these, ‘The archers
of England were taught to draw the bow-string to their right ear, while
other European nations only drew it to the breast.’ Now,” continued the
vicar, “if you try the difference of these postures, you will find that
a much longer arrow can be drawn to the ear than to the breast, because
the right arm has more room.”
The party now amused themselves for some time; each shooting in his
turn at the mark which was chosen for the trial; and with a success
which, considering it was their first attempt, the vicar declared to be
“quite marvellous.”
At the conclusion of the sport, Mr. Twaddleton informed his friends,
that parochial duties required his attendance at the vestry, but Mr.
Seymour told him that he should expect his company in the evening.
It was just six o’clock, when the sound of the porter’s bell, and the
rolling of carriage-wheels, announced the approach of some important
stranger to the lodge. It was Miss Villers. Were this a romance rather
than an instructive history, we should, at once, charge our pencil with
the glowing hues of the rainbow, and proceed to colour the outline
which the imagination of the reader must have already sketched: but the
character of the present composition fortunately renders such a task
unnecessary; we say “fortunately,” for the magazines of romance have
actually become insolvent from the numerous and heavy drafts of the
novel-writer; the regions of fancy have been so despoiled of their
blossoms, that scarcely a flower can be culled by him who would entwine
a garland for the brow of his heroine; and such even as may have
escaped the grasp of this voracious horde, will be found to have faded
under the withering influence of those insects of literature, which,
fluttering or creeping about their petals, have rendered their
fragrance pestilential, and turned their honey into bitterness. Where
can be found the emblem of that damask lip which, arched like the bow
of Cupid, shot an unerring dart, whenever a smile relaxed its tension?
We might describe the perfect symmetry of her form, but what language
could convey to the mind’s eye the witcheries with which the graces had
surrounded it? We might depict the features of her countenance, but how
could we catch and fix the varying expressions which lighted it up with
the magic glow of intelligence? We must, therefore, exercise the
judgment of Timanthes, and leave the reader to the sway of his own
imagination.
-----
Footnote 46:
Toxoph. ed. 1571. folio 166.
Footnote 47:
Markham’s Art of Archerie, 1634.
Footnote 48:
Gen. xlix. 23, 24.
Footnote 49:
MS. Cott. Claud. B. IV.
Footnote 50:
See Shakspeare’s Henry VI.
Footnote 51:
The ancient nobility of Greece were instructed by the Scythians in
the use of the bow, which in those days passed for a most princely
education. _Potter, Arch. Græc._ tom. ii. 1. iii. cap. 4. _Aquin.
Lex. Milit._ ii. 260.
Footnote 52:
The ‘_but_’ was a level mark; the ‘_pricke_,’ a mark of compass, but
certain in its distance; the ‘_roaver_,’ was a mark of uncertain
length.
------------------------------------------------------------------------
CHAPTER XV.
_A curious dialogue between the Vicar and Miss Villers.--An
enigma.--The riddles of Samson and Cleobulus.--Sound.--How
propagated by aërial vibration.--Music.--A learned discussion
touching the superior powers of ancient Music.--The magic of
Music, a game which the author believes is here described for
the first time.--Adventures by Moonlight.--Spirits of the
Valley._
On the following morning, Miss Villers, accompanied by her friends,
proceeded to Osterley Park, to pay her compliments to Major Snapwell,
and to add her entreaties to those of Mr. and Mrs. Seymour to induce
the venerable Major to spend a few days at Overton Lodge. The children,
of course, had a holiday; but was it a holiday? Tom and his sister have
been frequently heard to declare that they never passed a more dull and
listless day; and on resuming their scientific sports, their manner
sufficiently testified that increased pleasure which always accompanies
our return to an agreeable occupation.
“Mr. Twaddleton,” said Miss Villers, addressing the worthy vicar as he
entered the library at Overton, “I am happy to say that Major Snapwell
has consented to pass a few days with us, and I learn from him that you
have been most delightfully engaged in promoting a new scheme of
scientific instruction; it is a subject which greatly interests me, and
I shall be most happy in being allowed to become one of your party. To
the merits of this system I am no stranger,” continued the lady, “nor
am I unacquainted, sir, with the advantages which your antiquarian
knowledge has conferred; you have garnished the intellectual banquet
with some of the choicest flowers of literature.”
“You do me far too much honour, madam,” said the vicar, as a gracious
smile flitted over his countenance; “but I rejoice to find that you
attach a becoming importance to the researches of the antiquary. May I
be allowed to hope that you will favour me with a visit at the
vicarage, and inspect my poor collection of antiques?”
“I anticipate a great treat, I do assure you,” said Miss Villers; “but
you speak too humbly of a collection which the major informs me
contains some of the rarest relics of ancient days.”
“The major, madam, is no doubt a judge, an excellent judge, although he
is occasionally----but no matter--no matter. I certainly, as he justly
says, do possess some few remarkable specimens. I have, for instance,
an undoubted specimen of the leathern money coined by John of France;
some very tolerable samples of tapestry of the ‘high and low warp;’ a
series of sigilla or seals; as well as an interesting collection of
impressions in wax, taken from grants of William the Conqueror, and
what is curious, the colour of these waxen impressions is, without any
exception, green, with a view, as it has been said, to signify that the
acts should for ever continue fresh and in force. Let me consider,”
continued the vicar, “what other curiosities can I display for your
delight and approbation? Rock-basins; yes, the rock-basins from
Carn-breh. Ay, madam, you will be quite astonished at a specimen
which--” At this instant, Mr. and Mrs. Seymour, followed by the
children, entered the apartment, and abruptly cut the thread of the
vicar’s harangue.
“What do I hear?” exclaimed Mr. Seymour. “Rock-basins! for mercy’s
sake, my dear vicar, let us not again dive into those horrid basins of
Druidism; do but consider the martyrdom I have suffered on account of
those pools of lustration.”
“Well, well,” replied the vicar pettishly, “I will consent to reserve
the question for Miss Villers’s opinion, who, I have no doubt, will
readily assent to their authenticity. But I have another treasure
lately obtained from Cornwall, which you have not yet seen--a
Sepulchral stone!--‘_In vestibulo astat_,’ as the poet has it.”
“Why I never observed it as I passed through the entrance,” said Mr.
Seymour.
“Excuse me,” observed the vicar, “the _Vestibule_, if you please. You
doubtless know it was a custom amongst the Romans to have an altar
sacred to Vesta in the entrance of their houses, and hence the
term;--but I beg a thousand pardons--‘_venia sit dicto_’--I am perhaps
too critical.”
“Not only pardon, but thanks, my dear sir, for the information you have
afforded us,” said Mr. Seymour.
Miss Villers was now invited to be present at one of the scientific
conversations.
“I shall be grateful to you for so pleasing a privilege,” observed the
young lady; “and,” continued she, “may I be allowed to ask whether you
have not been lately teaching my young friends the operation of those
various toys, which act by the force of the air; the object I have in
view in asking this question you shall presently hear.”
“Papa has lately taught us the reason of the kite’s ascent, and the
action of the squirt, sucker, and pump,” said Tom.
“So I understood; and before you proceed with your sportive philosophy,
I hope your papa will allow you to try whether you can solve an enigma
I have composed for you.”
“A riddle!” exclaimed Louisa; “how delightful! Pray read it, papa, and
let us try to discover its meaning.”
Her father then opened the paper with which Miss Villers had presented
him, and read as follows:--
“Mortal, wouldst thou know my name,
Scan the pow’rs I proudly claim.
O’er this globe’s capacious round
With fairy sprightliness I bound;
To ev’ry clime, to ev’ry soil,
With equal hand I give my toil.
O’er sea and land my power extends,
To ev’ry herb my care descends.
Did I withhold my vital breath,
Nature’s forms would sink in death.
When confin’d, or swiftly driven
By angry spirits in the heaven,
My wrath in thunders I make known,
And discord claims me as her own.
’Tis love of freedom makes me wild,--
When uncontroll’d, my nature’s mild;
And oft the nymph, in dewy grot
Seeks solace from my plaintive note;
O’er lovers’ graves I waft a sigh,
And breathe the sound of sympathy.
And know, ye sons of Albion’s isle,
That when the Hero of the Nile,
Midst crowds with mournful pomp array’d,
In the cold lap of Earth was laid,
I sympathis’d with Britain’s tear,
And waved the banner o’er his bier.
’Tis I who from the trembling lyre,
Breathe tones of love and soft desire;
’Tis I, the spirit of the shell,
Who fill with notes the listening dell;
And, when the war-trump sounds alarms,
’Tis I who summon men to arms.
To man a slave, though free as air,
I grind his corn, his food prepare;
Should he to foreign climes proceed,
He yokes me like the neighing steed,
And, by my quick but easy motion,
He traverses the stormy ocean.
His children, too, my presence court,
To give them toys, and make them sport:
Without my aid, their kites would lie
As useless weights that ne’er could fly;
Their humming tops would soundless spin,
Unless I breath’d a spell within.
The modest maid, without my power,
Would wither like her kindred flower.
Unless my cup of sweets she sips,
Where are the rubies of her lips?
Unless my glowing rouge she seeks,
Where are the roses of her cheeks?
What art again can strew her tresses
With half the grace my skill possesses?
Ev’n goddesses are represented
In draperies which I invented.
Sometimes, ’tis true, I am so frail
As ruffian-like to raise your veil,
And thus to curious man reveal
The charms you modestly conceal.
Revenge the deed. Announce my Name,
For now you know the powers I claim.”
“It is extremely pretty,” exclaimed Louisa.
“It is beautiful,” said Tom; “but I should like to find out the riddle
it contains. What can that be which grinds our corn, and carries our
ships across the sea? Canvass? Yes; canvass clothes the sails of the
windmill and forms those of the ship.”
“And therefore visits every clime; while, as long as the sails remain
fixed, they are quite tractable and steady,” added Louisa.
“It will not do, Louisa; it cannot be canvass: for the sail is never
boisterous when it is controlled; but when let loose, it shivers in the
wind and is very unruly; whereas it is said in the riddle, ‘When
uncontroll’d my nature’s mild,’ which is quite the reverse. Let me see.
Can it be string? My top could not hum without string.”
“How can string prevent the modest maid from fading like a flower? What
says the vicar?” asked Louisa.
“_Davus sum, non Œdipus_,” exclaimed Mr. Twaddleton.
At this moment Miss Villers whispered in the ear of her little
favourite, who shortly afterwards exclaimed, “I have it, Tom,--it is
AIR.”
The juvenile group now attentively perused the enigma, in order to
discover whether its different parts would admit of such an
interpretation. As soon as they arrived at the passage in which was
described the waving of the banners over the bier of Nelson, Tom
declared that his sister must be wrong; and was proceeding to offer his
reasons, when Mr. Seymour interrupted him, by observing, it was that
passage which first suggested to his mind the solution of the enigma;
and satisfied him that Louisa was perfectly right.
“It so happened,” continued he, “that I was present during the awful
ceremony of Nelson’s interment in St. Paul’s; and never shall I forget
the thrilling effect which was produced on the assembled multitude, by
the solemn movement of the banners in the dome, as the bier slowly
advanced along the aisle of the cathedral; and which was accidentally
occasioned by a current of air from the western entrance, although, to
the eye of fancy, it seemed as if some attendant spirit had directed
the colours, under which the hero had bled and conquered, to offer this
supernatural testimony of respect and sorrow.”
Miss Villers observed, that Louisa had unquestionably solved the riddle.
“And pray, my dear Mr. Twaddleton,” said Mrs. Seymour, “what say you to
these puzzles and rhyming conundrums? Do you hold them in as much
horror as you would so many puns?”
“By no means, my good madam. An enigma is a perfectly orthodox species
of composition; and is, indeed, sanctioned by the highest authorities
of antiquity.”
“I believe,” observed Mr. Seymour, “that the pastime of riddle-making
was extremely popular amongst the Grecians. Plutarch, if I remember
correctly, has told us that the girls of his time worked at netting or
sewing, and that the most ingenious amongst them ‘made riddles.’”
“The most ancient riddle on record,” replied the vicar, “is to be found
in the fourteenth chapter of the book of Judges.”
“_And Samson said unto them, ‘I will now put forth a riddle unto you;
if ye can certainly declare it me within the seven days of the feast,
and find it out, then I will give you thirty sheets and thirty changes
of garments.’ And they said unto him, ‘Put forth thy riddle that we may
hear it.’ And he said unto them, ‘Out of the eater came forth meat, and
out of the strong came forth sweetness._’”
“And did they find it out?” asked Tom.
“My dear boy,” replied the vicar, “you must read the chapter to which I
have alluded, and you will thence learn all about this enigma.”
“We have also numerous riddles in prophane writers of ancient date,”
observed Mr. Seymour.
“Did you ever read of that invented by Cleobulus, one of the seven wise
men of Greece, who lived 570 years before Christ?” enquired the vicar.
“Pray be so kind as to relate it,” said Tom.
Mr. Twaddleton, in compliance with this request, proceeded as follows:--
“There is a father with twice six sons; these sons have each thirty
daughters, who are parti-coloured, having one cheek white, the other
black. They never see each other’s faces, nor live above twenty-four
hours.”
“A very strange and unsociable family!” observed Louisa.
“I should never guess it,” said Tom, “if I were to dedicate a year to
it.”
“You have, nevertheless, my boy, just pronounced the name of the said
father, and that, too, after a single moment’s consideration,” replied
the vicar.
“The name of the father!--how?--where?”
“It is a YEAR!”
“A year!” exclaimed the astonished boy.
“A year!” echoed Louisa; “to be sure it is; I now see it all clearly.
His ‘twice six sons’ are the twelve months; the ‘thirty daughters’ the
days of each month; and, since one day must necessarily pass away
before the next can arrive, they may be truly said never to see each
other’s faces.”
“Admirably expounded!” cried the vicar.
“And each day,” added Tom, “is certainly ‘parti-coloured,’ as it is
made up of light and darkness.”
“Good, again! The quick apprehension of these my little playmates,”
said Mr. Twaddleton, as he turned towards Miss Villers, “is highly
interesting; their minds, from well-regulated discipline, have acquired
the faculty, if I may be allowed the use of the metaphor, of
_winnowing_ a subject, so as completely to separate the grain from the
chaff.”
“It is my intention to proceed this morning with the consideration of
those toys which have the property of producing sound,” said Mr.
Seymour.
“I suppose you mean the whistle, whiz-gig, and humming-top,” observed
Tom.
“Your papa, no doubt, alludes to those instruments,” said the vicar,
“and I greatly approve of the arrangement; since our last lecture
embraced the operations of the atmosphere, a subject with which the
nature of sound is certainly intimately connected.”
“We have lately considered the phenomenon of wind, as produced by the
motions of the atmosphere, and I now propose to investigate another
species of agitation of which the air is susceptible, a kind of
vibratory or tremulous motion, which, striking on the drum of the ear,
produces SOUND.”
“Is it the air which produces sound!” said Louisa, with much surprise;
“I thought it was always occasioned by the vibrations of solid bodies.
Well do I remember, when Tom struck the finger-glass, that you
immediately silenced the sound by placing your hand upon it, and which
you told us stopped the vibration of the glass, and so destroyed the
sound.”
“You speak the truth, but not the whole truth,” replied her father.
“Sound is undoubtedly the result of certain motions, or vibrations,
produced in sonorous bodies, but these vibrations are communicated to
the air, and from thence to the ear, in a manner which I shall
presently explain.”
“Do you mean to say, papa, that, if air were entirely excluded, bodies
would be incapable of producing sound when struck?”
“Not exactly. Air is the usual conductor of sound, and unless some
other medium be substituted, the removal of it would prevent a sonorous
body from communicating any sensation to the ear. Liquids, however, are
capable of conveying the vibratory motion to the organ of hearing; for
sound can be heard under water. Solid bodies will also convey it, and
in a much more perfect and rapid manner(44); thus the slightest scratch
with a pin, upon one end of a long piece of timber, will be distinctly
heard on applying the ear to its opposite extremity. The tramping of a
horse is to be perceived at a greater distance by listening with the
ear in contact with the ground, than by attending to the sound conveyed
through the air; and hence, amongst many eastern tribes, it is a common
practice to ascertain the approach of an enemy, by applying the ear to
the ground. Upon the same principle, if we place our ear against a long
brick wall, and desire a person at a considerable distance to strike it
_once_ with a hammer, it will be heard _twice_, the first sound
travelling along the wall, the second through the air.”
“I thank you for that hint,” said the vicar. “I now understand the
principle of a new instrument which Dr. Doseall employs for examining
the pulsations of the heart. He places the end of a wooden rod upon the
breast, and applying the other extremity to his ear, declares that the
sounds, thus conveyed to it, enable him to form the most accurate
opinion in cases of diseased chest.”
“In the same manner,” observed Mrs. Seymour, “that you may hear the
boiling of the tea-kettle, by placing the end of the poker on the
vessel, and applying your ear to the handle.”
“I do not exactly understand what you mean by a _sonorous_ body. Will
not every body produce a sound when struck?” asked Fanny.
“Those bodies are called _sonorous_, which produce clear, distinct,
regular, and durable sounds, such as a bell, a drum, musical strings,
wind instruments, and so on.”
“And upon what does this peculiar property depend?” enquired Tom.
“Before I answer that question, I must explain the supposed nature of
those vibrations of the air, upon which sound depends; you will then
readily perceive why one species of matter should be better calculated
than another for exciting them. It is generally believed that sound is
conveyed through air by a succession of pulsations similar to those
which are occasioned on the surface of smooth water by throwing a
pebble into it. This at first produces a small circular wave round the
spot in which the stone falls; the wave spreads, and gradually
communicates its motion to the adjacent waters, producing similar waves
to a considerable extent. The same kind of waves are produced in the
air by the motion of a sonorous body, which will of course be in the
centre, and the waves or pulsations will diminish in strength as they
recede from that centre, until at last they become too weak to produce
any effect on the ear.”
“When I strike a bell, then do I produce exactly the same motion in the
air, that I do in the water by throwing a stone into it?” asked Louisa.
“With this difference,” replied her father, “that as air is an elastic
fluid, the motion does not consist of regularly extending waves, but of
vibrations, which are composed of a motion forwards and backwards; the
undulations of the air differ also from those of the water, in not
being confined to a plane, but in diverging in all directions from the
centre; or, in other words, the aërial undulations are spherical.”
“It is a very puzzling subject,” cried Tom.
“I cannot understand,” said Louisa, “how the motion of the air can
extend so as to convey sound to a distance, if, as papa says, the air
moves backwards as well as forwards.”
“I see your difficulty, and will endeavour to remove it; attend to me.
The first set of undulations which are produced immediately around the
sonorous body, by pressing against the contiguous air, condense it. The
condensed air, though impelled forward by the pressure, re-acts on the
first set of undulations, driving them back again. The second set which
have been put in action, in their turn, communicate their motion, and
are themselves driven back by reaction. Thus there is a succession of
waves in the air, corresponding with the succession of waves in the
water.”
“Now I understand why sound requires some time to travel from a distant
object to the ear, as you explained to us upon a former occasion,”[53]
said Louisa.
“But you have not yet told us what renders a body sonorous,” observed
Tom.
“Its elasticity: a ball of damp clay, which does not possess this
property, will produce no other sound, when struck, but that which
arises from the condensation of the small portion of air between the
clay and the hammer which strikes it. A hollow ball of brass will
produce more sound, because it is elastic; but still very little effect
will arise from this, since a ball is the worst shape for admitting of
vibration, on account of its forming an arch or dome, in every
direction, so that one part stiffens and sustains the other; but if
such a ball be divided, and the edge of one half of it struck, a loud,
clear, and distinct tone will be produced; because a hemisphere will
admit of the exertion of elasticity, or of momentary change of figure,
which is conducive to the perfection of sound; and accordingly the
bells used for clocks, and for musical purposes, have generally such a
figure.”
“I see clearly,” said Louisa, “that it is the vibration of a sonorous
body that communicates the necessary motions to the air; and I suppose
that a body vibrates in proportion to its elasticity.”
“Certainly it does: but to render this subject still more intelligible,
I have prepared a diagram.”
Mr. Seymour then exhibited a figure, of which the annexed is a copy,
and proceeded to explain it in the following manner:--
[Illustration: Diagram of a string vibrating.]
“You are well aware that an elastic body, after having been struck, not
only returns to its former situation, but having acquired momentum by
its velocity, like the pendulum or swing,[54] springs out on the
opposite side. If, then, I draw the string A B, which is made fast at
both ends, to C, it will not only return to its original position, but
proceed onwards to D. This is the first vibration, at the end of which
it will retain sufficient velocity to bring it to E, and back again to
F, which constitutes its second vibration; the third vibration will
carry it only to G and H, and so on, till the resistance of the air
destroys its motion.”
“That is exactly like the swing or pendulum,” said Tom.
“As you are struck with the resemblance, take care and preserve the
remembrance of it; for I shall, hereafter, have occasion to revert to
it.”
“As I now understand how sound is produced and carried to a distance, I
should much like to learn the cause of different tones,” said Louisa.
“Fond as you are of music, my dear Louisa, I am not surprised at the
wish you have just expressed to become acquainted with the nature of
musical sounds; I shall, therefore, endeavour to convey, in as simple a
manner as possible, the theory which has been proposed for their
explanation. I think you will immediately perceive that, if the aërial
waves which I have endeavoured to describe, should be irregular, or run
into each other, there must arise a confusion of sounds; thus
_discords_ may be readily imagined to be produced whenever a second
vibration shall commence before the first is finished, so as to meet it
half-way on its return, and interrupt it in its course. In like manner
may we conceive the general nature of those arrangements upon which
_unison_ and _concord_ depend: where the vibrations are performed in
equal times, the same tone is produced by both, and they are said to be
_in unison_; but _concord_, as you well know, is not confined to
unison, for two different tones harmonize in a variety of cases. If,
for example the particles of one sonorous body vibrate in double the
time of another, the second vibration of the latter will strike the ear
at the same instant as the first vibration of the former; and this is
the ‘concord of an _octave_.’ When the vibrations are as 2 to 3, the
coincidence will be at every third vibration of the quickest, which,
therefore, is the next degree of perfection, and is called a
‘_diapente_,’ or ‘fifth;’ while the vibration of 3 to 4 will produce
the ‘_diatessaron_,’ or ‘fourth;’ but this, and the next which follow
in order, are not so agreeable to the judicious ear, and are therefore
called ‘_imperfect concords_.’”
Louisa here enquired whether the difference in the acuteness of a sound
did not depend upon the nature of the vibrations; and her father, in
reply, stated that it depended entirely upon the degree of quickness
with which the vibrations were performed: the slower the vibration, the
graver the tone; the quicker, the more acute.[55]
“But, if I strike any one note of the instrument repeatedly, whether
quickly or slowly, it always gives the same tone,” observed Louisa.
“To understand that fact,” replied her father, “you must remember that
the vibrations of bodies are regulated by laws very similar to those of
the pendulum; consequently the duration of the vibrations of strings or
chords depends upon their length, and thickness; for if two strings of
equal magnitude, but with their lengths as 2 to 1, be equally
stretched, their vibrations will be in the same ratio; therefore the
shortest will make two vibrations, while the longest makes one: but the
vibrations of the same string will always be the same whether it be
struck quickly or slowly, upon the principle of the _isochronous_
property of the pendulum, already described.”
“Upon my word, Mr. Seymour,” cried Mr. Twaddleton, “you are getting out
of your depth; pray let us take leave of this subject, for I am quite
sure that my young friends have already received more than they can
carry away.”
“I submit, my good sir; and in return for my compliance,” said Mr.
Seymour, “use your influence over Miss Villers, and induce her to
favour us with a practical illustration of our subject upon the
piano-forte.”
“Most cheerfully; but my intercession is quite unnecessary, for I am
sure that our fair friend is no disciple of Tigellius.”[56]
“I am ever ready, sir, to comply with the wishes of those I respect. I
consider the caprice which our sex too often displays upon these
occasions, as not only a breach of good manners, but an evidence of
unpardonable vanity.”
“Pray, Miss Villers, may I be allowed to ask whether you have ever
directed your enquiries into the nature of ancient music? it must have
been very superior to that of modern ages,” said Mr. Twaddleton.
“Upon a question of such doubt and difficulty, I feel that it would ill
become a person of my very limited knowledge to offer an opinion;
although I am willing to confess that the subject has often engaged my
attention; and you could not afford me a greater gratification than by
clearing up some of those doubts which have perplexed me. It is, I
believe, admitted, that we are unable to ascertain the real nature of
ancient music: but it is evident that it was an art with which mankind
was extremely delighted; for not only the poets, but the historians and
philosophers, of the best ages of Greece and Rome, are as diffuse in
its praises, as of those arts concerning which sufficient remains have
descended to evince the truth of their panegyrics.”
“Nothing, as you very justly observe, is now left us, but conjecture,”
said the vicar; “and yet it is impossible to read the accounts of the
extraordinary effects produced by the different ‘modes’ of ancient
music, without entertaining a strong conviction of its great
superiority over that of modern times. What have we, my dear Miss
Villers, to compare with the soft ‘_Lydian_,’ the grave ‘_Dorian_,’ or
the furious ‘_Phrygian_;’ to say nothing of the subaltern modes of
Aristides Quintilianus and others; such, for example, as the
‘_erotic_,’ ‘_comic_,’ and ‘_encomiastic_?’ What modern strains can
produce the effects which are recorded to have followed the performance
of Timotheus, the director of the music of Alexander the Great? One
day, while the prince was at table, the musician performed an air in
the Phrygian mode, which made such an impression on him, that, being
already heated with wine, he flew to his arms, and was going to attack
his guests, had not Timotheus immediately changed the style of his
performance to the sub-Phrygian, or Lydian. This mode calmed the
impetuous fury of the monarch, and induced him to resume his place at
table. Music,” continued the vicar, “has, in modern times, so fallen
from this degree of majesty and power, as to induce some persons to
doubt the truth of the historical statements.”
“I confess, Mr. Twaddleton,” said Miss Villers, “that I have always
been inclined to regard ancient music as the mere vehicle of poetry;
and to attribute to the power of the latter that influence which you
appear to refer exclusively to the former.”
“I am willing to admit,” replied the vicar, “that in the ancient
theatre, music always accompanied her sister science, assisting,
animating, and supporting her; in short, that she was, in all respects,
her friend and fellow labourer. ‘_Qualem decet esse sororem_,’ as the
poet has it: but does not this rather prove that poetry, in itself, was
insufficient to produce its effects without the aid of music? In
farther proof of the power of ancient music, permit me to remind you
that Plato has said, ‘No change can be made in music without affecting
the constitution of the state;’ and Aristotle, who seems to have
written his Politics only to oppose the sentiments of Plato,
nevertheless agrees with him, concerning the power which music has over
mortals; and has not the judicious Polybius told us that music was
necessary to soften the manners of the Arcadians? In short, madam,
music has lost its power over the passions of mankind, and this can
only have happened in consequence of its having degenerated from its
ancient purity and grandeur. If any one should have the hardihood to
deny this my position, let him attend a modern rout in London. I have
seen, my dear Miss Villers, a party at a whist-table, a dozen persons
in _tête-à-têtes_, and as many solitary individuals, sitting like
automatons, not one of them being moved by the concord of sweet sounds,
with which some lady has been endeavouring to delight them. Had
Timotheus appeared amongst them! hey, Miss Villers? I think I see the
party at the whist-table, as his lyre successively changed from the
Lydian to the Phrygian mode. I must, however, in justice state, that I
once did see a lady lay down her cards in an apparent state of ecstasy,
as a chorus of Handel suddenly burst upon her ear.”
“And what might that chorus have been?” said Mr. Seymour, “‘_Blest be
the hand?_’ But, joking apart, you appear to have satisfied your mind
upon a point which all the learning of Europe has left in a state of
doubt and perplexity.”
“I have merely delivered an opinion, sir; you perhaps will favour us
with your judgment.”
“The subject under discussion, my good sir, is one upon which no person
can ever deliver a judgment.”
“And pray, Mr. Seymour, why not?”
“For this plain reason, that it is not possible we can _hear_ both
sides.”
“Psha! will you never cease to sully the pure stream of enquiry with
the dregs of ridicule?”
“Well, then, to be serious; I agree with Miss Villers, that ancient
music, whatever might have been its powers, was wholly indebted to the
poetry which accompanied it for its influence over the feelings of
mankind. It could not have been otherwise. The ancient instruments, as
represented in sculpture, appear so simple as to be apparently
incapable of producing great effects; and, indeed, amongst the writings
of Aristoxenus, the oldest musical author, we cannot discover a trace
of melody or harmony, such as we understand by _air_ accompanied with
different parts.”
“To that very simplicity am I disposed to refer the charm of ancient
music,” said the vicar; “it was addressed to the _ear_, sir, whereas
modern music is addressed to the _eye_; dexterity of execution is,
now-a-days, more valued than beauty of composition; the sweetest
shepherd that ever piped on his Doric reed, would be less applauded
than he who can make his pipe squeak for the space of five minutes
without respiration. The ancients knew better than to suffer the energy
and accentuation of their rhythm to be so destroyed; and only mark,
sir, the extreme jealousy with which they regarded every attempt to
injure this simplicity; it even became a subject of legislation; and
you no doubt remember the decree issued against Timotheus; which, as
well as I recollect, ran thus, ‘Whereas Timotheus the Milesian, coming
to our city, has dishonoured our ancient music, and despising the lyre
of seven strings, has, by the introduction of a greater variety of
notes, corrupted the ears of our youth; and, by the number of his
strings and the novelty of his melody, has given to our music an
effeminate and artificial dress, instead of the plain and orderly one
in which it has hitherto appeared; rendering melody infamous, by
composing in the chromatic, instead of the enharmonic. The kings and
the ephori have, therefore, resolved to pass censure upon Timotheus for
these things; and farther, to oblige him to cut all the superfluous
strings of his _eleven_, leaving only the _seven_ tones, and to banish
him from our city, that men may be warned for the future not to
introduce into Sparta any unbecoming customs.’”
“And now, my dear vicar, have you done? Have you said all you think
necessary, in defence of ancient music? If so, hear me, as the advocate
of modern harmony. In the first place, there is not an anecdote which
can be adduced in support of your side of the question, that may not be
met with one parallel, and equally strong, in defence of mine. You cite
the authority of Plato, to show that the constitution of a state may be
affected by changing its national music. What said the great Lord
Chatham?--‘_Give me the making of the national ballads, and I care not
who makes the laws_;’ and the effects produced on the English people by
Dibdin’s songs, fully justified the maxim: but remember Mr. Twaddleton,
it was not the music, but the _poetry_ of those songs, which kindled
the patriotic feelings which saved our country; and I apprehend that
this has been the case in all ages, where the power of music has been
said to excite the feelings of the populace. We know that the ancient
bards of our own country called forth the emotions of their hearers by
the poetry of their songs; and with what success they practised their
calling we may imagine from the fact that Edward the First, in his
conquest of Wales, had recourse to the barbarous expedient of murdering
all the bards, from the many obstacles they threw in his way, by the
strong hold which they had over the minds of the people. You have told
us a story of Timotheus, and the influence of his harp over a drunken
monarch. If this is adduced in proof of the power of ancient music, you
must, at least, admit that modern times have also had a Timotheus, who
could excite or calm, at his pleasure, the most impetuous emotions.
Henry III. king of France, says ‘_Le Journal de Sancy_,’ having given a
concert on occasion of the marriage of the Duke de Joyeuse, Claudin le
Jeune, a celebrated musician of that period, executed certain airs,
which had such an effect on a young nobleman, that he drew his sword,
and challenged every one near him to combat; but Claudin, equally
prudent as Timotheus, instantly changed to an air, _sub-Phrygian_, or
_Lydian_, I suppose, which appeased the furious youth. But what shall
we say of Stradella, the celebrated composer, whose music made the
daggers drop from the hands of his assassins? Stradella was attacked by
three desperadoes, who had been hired to assassinate him; but,
fortunately, they had an ear sensible to harmony. While waiting for a
favourable opportunity to execute their purpose they entered the church
of St. John de Lateran, during the performance of an oratorio, composed
by the person whom they intended to destroy, and were so affected by
the music, that they abandoned their design, and even waited on the
musician to apprise him of his danger. Stradella, however, was not
always so fortunate; other assassins, who apparently had no ear for
music, stabbed him some time afterwards at Genoa.”
“And thus afforded a practical illustration of a passage of
Shakspeare,” exclaimed the vicar,
“‘The man that hath no music in himself,
Nor is not mov’d with concord of sweet sounds,
Is fit for treasons, stratagems, and spoils;
The motions of his spirit are dull as night,
And his affections dark as Erebus:
Let no such man be trusted.’”
“Are you satisfied?” asked Mr. Seymour; “if not, I will proceed to tell
you how Palma, a Neapolitan, induced a creditor who came to arrest him,
not only to remit his debt, but to contribute a sum for his support. I
will also relate an anecdote of Farinelli the actor, who having a
pathetic air to sing on the stage to a tyrant who had taken him
prisoner, the person who performed the part of the tyrant, and was to
have refused his request, was so affected by the music, that he
actually melted into tears, and clasped the captive in his arms.”
“Enough, enough!” exclaimed the vicar. “I see plainly that you believe
not in the power of music.”
“In that you wrong me. I certainly do not believe that the ancients
were better skilled than ourselves in music; and I have been anxious to
convince you that there are as many modern as ancient stories, in proof
of the influence of harmony over our feelings; but no one will deny
that music is capable of producing extraordinary effects. Let us only
interrogate ourselves, and examine what have been our sensations on
hearing a majestic or warlike piece of music, or a tender and pathetic
air sung or played with expression. Who does not feel that the latter
tends as much to melt the soul and dispose it to pleasure, as the
former to animate and exalt it? There is a celebrated air in
Switzerland, which, I have no doubt, Miss Villers will presently play
to us, called ‘_Rans des Vaches_,’ and which had such an extraordinary
effect on the Swiss troops in the French service, that they always fell
into a deep melancholy whenever they heard it. Louis XIV, therefore,
forbade it ever to be played in France, under the pain of a severe
penalty. We are also told of a Scotch air, ‘_Lochaber no more_,’ which
had a similar effect on the natives of Scotland. Never shall I forget
the effect produced upon myself by the impressive requiem of Jomelli,
as performed at the chapel of the Portuguese embassy to the memory of
the late king of Portugal. The movement with which it commenced was a
deep and hollow murmur, that seemed to swell from the tomb, and with
which the voices of spirits imperceptibly rose, and intermingled;--a
brilliant movement interposed,--it was a ray of hope that pierced the
gloom of the sepulchre!”
“I think,” said Miss Villers, “that I can exactly appreciate the nature
and extent of Mr. Seymour’s opinion upon the question at issue. He does
not deny the charm which the simple music of the ancients must have
exercised over the hearer, although he attributes much of the effect to
the poetry, of which it may certainly be said to have been the vehicle;
and he evidently concurs with you, Mr. Twaddleton, in thinking that,
owing to the intricate combinations of modern harmony, our astonishment
at the execution of the artist too frequently overcomes the influence
of the musical tones upon our passions. I perceive, however, from the
expression of our friend’s countenance,” continued the young lady,
“that, like a true antiquary, he clings to his subject, though his
support be no stronger than a cobweb; under such circumstances I may be
permitted to declare my sentiments upon the occasion, and I shall avail
myself of this opportunity to express my humble testimony of gratitude,
for the information and pleasure which I have just derived from your
conversation. I believe then, gentlemen, that the language of modern
music is no less forcible and expressive than that of ancient days; and
if you will only allow me to exemplify this truth by an experiment, I
feel convinced that the vicar will become my proselyte.”
“Indeed, madam! Well, I will consent to trust the cause in your hands,”
said Mr. Twaddleton.
“Allow me then to ask you, sir, whether you have ever heard of a game,
which is justly entitled to the appellation of the MAGIC OF MUSIC?”
“Never,” replied the vicar; “nor can I imagine either the nature, or
objects of such a game.”
“Its object is to display the power of music as an expressive language;
the manner in which I propose to exemplify it, I will, with your
permission, explain in a few words. The musical performer shall place
herself at the harp, or piano-forte, surrounded by the party who are
desirous of witnessing the pastime; the person to be operated upon must
retire from the apartment, until the service which, under the direction
of the music, it is determined he shall perform, is duly agreed upon
and arranged. Such person is then to be re-admitted; not a word, look,
or gesture, is to escape from any one present; by the expression of the
music alone is he to receive his instructions, and, unless I am much
deceived, you will find that this is amply sufficient for the purpose.”
“My dear madam, the thing is utterly impossible,” exclaimed the vicar.
“It cannot be done; unless, indeed, you really possess the secret of
the ancient ‘_modes_,’ which were not even known to Meibomius, the
learned commentator upon the Greek musician Alypius; nay, Isaac Vossius
himself, the expounder of rhythm, were he now alive, would never credit
it.”
“Are you willing to make the experiment,” said Miss Villers; “if so, be
so kind as to leave the room for a few minutes.”
The vicar accordingly prepared to depart, casting at the same time,
upon his fair companion, a look which sufficiently expressed the
scepticism he felt upon the occasion.
“But you have not told me,” said he, “by what signal I am to return,
and submit to the proposed ordeal.”
“The music will inform you, if you pay sufficient attention to its
language,” replied Miss Villers.
The door having been carefully closed, the company were consulted, in a
whisper, as to the service they should require the vicar to perform. “I
should propose,” said Miss Villers, “that Mr. Twaddleton be directed to
take a rose out of the basket of flowers on the chimney-piece, and
having smelt it, to carry it to the harp.”
“And do you propose to express all these different movements by the aid
of music? If you succeed, there must be an end to the vicar’s
scepticism,” observed Mr. Seymour.
“If I fail upon this occasion, it will be the first time,” said Miss
Villers: “but you must all promise to be silent, and to maintain the
most absolute command over your countenances.”
Miss Villers seated herself at the piano-forte, and played off an
elegant and sparkling overture, which so delighted Mrs. Seymour that
she involuntarily exclaimed, “If music can be made to speak an
intelligible language, it must be under the guidance of Miss Villers.”
“Hush,” cried the performer, in a half whisper: “I am now about to
summon the vicar into the room, and we must be as silent as
Carthusians.”
She accordingly, with exquisite taste and address, introduced the air
of “_Open the door, Lord Gregory_,” into which she infused so much
expression, that the vicar must have been as dull as Midas had he not
instantly caught its meaning. Nor were the lady’s hopes disappointed.
Mr. Twaddleton entered, and appeared as if anxious to address the
performer; but an intelligible glance from Mr. Seymour recalled him to
his duty, and hermetically sealed his lips. His intention had been,
doubtless, to enquire whether his appearance were seasonable; but the
question was anticipated by Miss Villers, who immediately on his
entrance struck up the air of “_See the conquering Hero comes_,” which,
at once, satisfied his doubts, and conveyed, in language not to be
misunderstood, the sanction of the enchantress, to whose spells he had
so unreservedly intrusted himself.
The vicar had been told that he was to perform certain acts on his
re-admission into the room; but, thought he, how am I to discover the
thread which is to guide me through so perplexing a maze? I can
discover at this moment nothing but a concord of sweet sounds, that
would rather dispose me to listen in profound repose, than to enter
upon any service of exertion. Miss Villers saw and guessed the nature
of his embarrassment, and changing the melody, struck into the air of
“_Hearken and I will tell thee how_.” She then, by a succession of
well-selected chords, which were now played ‘_piano_,’ and now
‘_forte_,’ convinced the vicar that she commanded an instrument fully
capable of readily and forcibly expressing encouragement and repulse in
all its degrees.
“Thus much then is certain,” mentally ejaculated the vicar, “that she
is enabled, by the aid of music, to signify her approbation, or
disapprobation, of any act which I may attempt to perform. I
accordingly predicate of this said music, that it is, _bonâ fide_, a
logical weapon; inasmuch as it can affirm and deny. It, therefore, only
remains for me, knowing as I do that I have some act to perform, to
ascertain the ‘_locus_’ or ‘_ubi_,’ for the act in question, whatever
it may be, must of necessity be done or accomplished ‘_in proprio
loco_,’ or in some definite part of the room.” With this determination,
founded, as he believed it to be, on the unerring basis of Aristotelian
logic, he advanced towards the table; but the loud and discordant
sounds of the instrument at once convinced him, that, however correct
his notions might be with reference to the ‘_substance_’ or first
‘_predicament_,’ they were evidently erroneous as to the ‘_accidents_,’
of ‘time,’ ‘place,’ and ‘relation;’ at least, such were the ideas that
floated through the categorical organ of his cranium, and he
accordingly faced about, and made a retreat towards the window; but the
notes now became still more clamorous, and increased in vehemence. Ay,
ay, thought he, it is quite evident that I am receding from the theatre
of action; and with this conviction he diverted his steps into a
different direction, and, in a slow pace, tracked the path by his ear,
with as much sagacity as a dog follows his prey by his nose. As he
approached the fire-place, the storm of sounds gradually subsided,
until a peaceful murmur breathed around, which finally died away as the
vicar placed his hand upon the chimney-piece. So then it appears, after
all, that I have some service to perform at the fire-side. It is,
doubtless, to sit down, thought he, as he espied the elbow-chair,
which, at that moment, appeared to his fancy, as if stretching forth
its hospitable arms to receive him; but scarcely had he answered the
imaginary invitation of his old friend, by presenting the nether part
of his person to its luxurious lap of down, than a sudden _sforzato_,
or crash in the minor key, made him rebound upon his legs, as nimbly as
though the cushion had been a bed of thorns. Miss Villers now resolved
the discord, and dexterously dashed into an allegro movement, in which
she introduced the air of “_How sweet are the flowers that grow!_”
The vicar’s face mantled with a smile, as the bouquet on the
chimney-piece met his eye, and harmonised with the sounds that floated
in his ear. It is evident, thought he, that those flowers are the
objects of my pursuit,--but what was he to do with them? The musician
solved the question, by tastefully exchanging the former air for that
of “_Ask if yon damask rose be sweet_.” No sooner had these notes
delivered their melodious errand to the subtle ear of the vicar, than
he instantly seized the rose, and carried it in triumph to his
olfactory organs; at the same moment the music ceased. The pause,
however, was but of short duration; for Miss Villers, by resuming her
labours, intimated that some farther service was expected. Was he to
return the rose? Certainly not; for the attempt was marked by strong
disapprobation. Was he to take it out of the room? The music put a
decided negative upon that movement; for the vicar had scarcely
measured half the distance of the apartment before the air of “_Fly not
yet_” arrested his steps. By a continuation of the same varying style
of expression, and strongly marked rhythm, the vicar was shortly led to
affix the rose upon the harp.
“Upon my word,” exclaimed the vicar, “I shall no longer hesitate to
credit the story related in ‘Peter Simple,’ of a certain lady who
played so exquisitely, that upon introducing an imitation of thunder,
the cream for tea became sour, besides three casks of beer in the
cellar!”
In closing our account of this interesting scene, it is scarcely
necessary to describe the delight and mirth of the juvenile party. It
was, in truth, a very extraordinary exhibition; and when the reader
considers that, beyond what was furnished by the expressive language of
music, the vicar did not receive a single hint for his guidance, he
may, perhaps, cherish some scepticism upon the subject; but we can
assure him that we have repeatedly witnessed, not only a similar but a
still more complicated performance of the same kind, and with equal
success.(45)
The evening of the day on which this musical divertisement was
performed, was one of those which so frequently occur in August, when
sultry heat is succeeded by refreshing coolness. Isabella Villers
possessed a quick sensibility to the beauties of nature, and she
quitted the drawing-room to enjoy, without interruption, that pensive
quiet which maintained an undisputed dominion. The moon had but just
risen, tipping the summits of the wood with silver, while it left the
mass of foliage in deeper shadow. Never was there a fairy scene better
calculated to awaken the emotions of the heart, or to kindle the
energies of the imagination. The hour too was propitious to the
indulgence of that undefined species of reverie which is the refinement
of intellectual pleasure. Having traversed the winding path of the wood
for some distance, she found herself in one of those sequestered glades
we have formerly described. She seated herself on a rustic bench,
tastefully formed out of an aged oak, whose venerable figure was
bending under the hand of Time, and her mind was gratefully lulled into
a pensive calm by the review of past events, as the ear is soothed by
the murmur of wild and distant music. A sudden breath of wind, as it
swept the foliage, aroused her from her reverie, and turned the current
of her ideas from past scenes to future prospects. The moon, as if in
sympathy, suddenly peered through the sylvan avenue, and threw her rays
upon one of those statues which we have already described as giving
such an air of classic sanctity to these secluded glades. It was the
figure of TIME, which in the gloom of the wood had hitherto escaped her
observation. To a mind of exuberant fancy, a leaf cannot fall to the
ground, nor a zephyr waft the fragrance of the violet on its dewy
pinions, without conveying some beautiful emblem of morality. Isabella
rose from her seat, and approached the figure, whose hoary countenance
appeared as if lighted up into a placid smile by the beams of the moon,
which fell directly upon it; her eye glanced from his face to his
scythe; its blade was hidden in a cluster of roses--Were I susceptible
of a superstitious impression, thought Isabella, did ever a
circumstance present itself better calculated to justify its
indulgence? On the pedestal of the figure was a basso relievo, in which
Time appeared in the act of shivering into pieces the club of Hercules
with a crutch. In a few minutes, she quitted the scene, which, in spite
of her better reason, she could not wholly divest of its prophetic
influence, and proceeding along the winding path, at length descended
into the valley. The moon was at this time shrouded in dark clouds, and
although, by a painful effort, Isabella Villers summoned all the powers
of her vision, the objects around her remained invisible, until the eye
had so far accommodated itself to the gloom, as to recognise the white
foam of the waterfall. The moon now gave a coy and furtive glance, the
water for an instant sparkled in her beams, and then was lost in deeper
shadow. A spectre of human form, but of gigantic stature, arose from
the spot to which the eyes of Isabella had been directed--was it the
spirit of the Fountain? It appeared to advance, but the moon once again
shining forth in splendour, it vanished.
“And what seem’d corporal melted
As breath into the wind.”
The courage of Isabella was destined to sustain another trial, for
scarcely had the vision disappeared than she distinctly heard her own
name pronounced; and since, from the direction of the sound, she well
knew that the spot from which it issued was inaccessible, we ought not
to feel surprised at her having at the instant referred it to a
supernatural origin--it was, however, but the illusion of the moment,
and she determined to return to the house and submit the events of the
evening to the judgment of Mr. Seymour.
We shall not trespass any longer upon the patience of the reader, than
to state that Miss Villers arrived safely at the lodge, and very
shortly afterwards retired to rest. With your permission, gentle
reader, we will follow her example; for, to say the truth, our
lamp--that midnight sun which illumines the path of the author, is
dimmed by the dark clouds that lower at its setting; our Pegasus, the
pen, which has raced for so many hours over the snowy plains of
foolscap, is fairly “done up,” and refuses any longer to sip of that
spring which can alone sustain its powers, and impart utility to its
movements.
Ecce!
[Illustration: A feather.]
-----
Footnote 53:
See p. 35.
Footnote 54:
See page 163, et seq.
Footnote 55:
The number of vibrations made by the wings of insects, as before
stated, has been ingeniously deduced from the tone which they produce.
Footnote 56:
Horat. Sat. lib. i. sat. 3.
------------------------------------------------------------------------
CHAPTER XVI.
_Origin of the Crescent as the Turkish Ensign.--Apparitions
dispelled by Philosophy.--Musical instruments classed under
three divisions.--Mixed instruments.--Theory of wind
instruments.--The Jew’s Harp.--The Statue of Memnon.--An
interesting experiment.--The Flute.--The whiz-gig,
etc.--Echoes.--The Whispering Gallery in the Dome of St.
Paul’s.--The Speaking Trumpet.--The Invisible Girl.--Other
Acoustic Amusements._
On entering the library on the following morning, Mr. Seymour informed
Miss Villers, that Major Snapwell had taken his departure, in order to
breakfast with the vicar, and that he had invited Tom and Louisa to
accompany him, for the sake of inspecting the cabinet of medals; but he
added, that he expected the return of the party at two o’clock, when he
proposed to give them a lecture upon the philosophy of the several toys
which are indebted for their action to atmospheric vibrations.
“Suppose, then,” said Miss Villers, “that we walk towards Forest Lane,
and meet them on their return. This arrangement,” she added, “will
afford me an opportunity of communicating to you the history of some
adventures I encountered last evening, and of taking your opinion upon
them.”
“You well know,” answered Mr. Seymour, “that you may always command my
services--but you have really raised my curiosity: what can be the
nature of the adventures you speak of?”
Miss Villers then entered into a particular account of all she saw and
heard the preceding evening; with which the reader is already
acquainted. Mr. Seymour, however, suggested the propriety of abstaining
from any discussion upon the subject until the children were present to
hear it; for, said he, “I am most desirous that they should be
familiarized with those natural sources of illusion which enlighten the
wise, while they minister to the superstitious fears of the ignorant.”
They had not reached the entrance of Forest Lane, before they perceived
the vicar with Tom and Louisa, followed by the Major.
“Papa,” cried Tom, as he ran to meet his father, “we have had a most
delightful morning; amongst other things, do you know we have found out
the meaning of the crescent which the Turks always wear, and use as
their ensign.”
“Indeed! well, then, let me hear your explanation,” said his father.
Major Snapwell and the vicar had by this time joined the party, and
with their assistance Tom was enabled to offer the following account of
it.--The crescent appears on the early coins of Byzantium, and was
intended to commemorate the defeat of Philip of Macedon, who, as he was
about to storm it on a cloudy night, was discovered by the sudden light
of the moon. When the Turks entered Constantinople, they found this
ancient badge in various parts of the city, and suspecting that it
might possess some magical power, they assumed the symbol and its power
to themselves; so that the crescent became, and still continues to be,
the chief Turkish ensign.
“Well, I must own that you have given me a new and very curious piece
of historical information, and I thank you for it,” said Mr. Seymour.
“Medals, then, are occasionally of some little use,” remarked the
vicar, with a sarcastic smile; for if the truth must be told, the
reverend antiquary had been a little nettled as usual by the freedom
with which Major Snapwell had criticised some of his rarities; but let
that pass.
As soon as the party reassembled after the excursion of the morning,
the circumstances which so greatly astonished Miss Villers on the
preceding evening, were again related by her.
“My dear young lady,” observed Mr. Seymour, “I never heard a better
story for illustrating the illusions to which the senses are exposed;
and if you will read the second letter on ‘Natural Magic,’ by Sir David
Brewster, you will obtain a ready explanation of your vision--but let
us examine it philosophically. In the first place you acknowledge that
your imagination had been previously excited during your ramble through
the wood, and more especially by your reverie at the statue of Time;
now it is well known that such a condition of the mind prepares and
adapts the organs of vision for those illusions which I am about to
explain. You have told us that, on your descent into the valley, the
moon had withdrawn its light, and several minutes had elapsed before an
object became visible, and that was the _white_ foam of the waterfall.”
“If I rightly remember, Brewster has stated that the spectres that are
conjured up by the imagination are always _white_, because no other
colour can be seen at night,” observed Mrs. Seymour.
“Undoubtedly,” replied her husband; “and as these spectres are formed
out of objects whose different parts reflect different degrees of
light, their fainter parts will appear and disappear with the ever
varying degree of illumination which is occasioned by the moon shining
through a veil of clouds, and a change even of shape will be thus
produced which will impart to the object in question the semblance of a
living form. The actual state of the eye itself will also greatly
assist in completing such an illusion; for, in consequence of the small
degree of light, the pupil expands to nearly the whole width of the
iris, in order to collect every ray, and in such a condition it cannot
accommodate itself to see near objects distinctly, so that the form of
a body actually becomes more shadowy and confused when it comes within
the very distance at which we count upon obtaining the best view of it.”
“You have certainly explained the reason why bodies seen under a faint
illumination may appear distorted and caricatured; indeed, I now
remember that Sir Walter Scott, in his “Pirate,” has given us a very
good illustration; for Cleveland when abandoned on Coffin bay is said
to have seen many a dim and undefined spectre in the misty dawn. But I
am still at a loss to understand how the vision I witnessed in the
valley could have been conjured up,” said Miss Villers.
“It was the doubtful and flickering light of the clouded moon upon the
mass of white sandstone,” said Mr. Seymour. “It is a great law of the
imagination, that a likeness in part tends to become a likeness of the
whole. The sandstone presented, in the first instance, a form somewhat
resembling the human figure, or some part of it, when your active
imagination immediately completed the outline; just in the same way as
we trace images in the fire, or castles in the clouds, or grotesque
figures of men and animals on damp walls.”(46)
“I am satisfied,” said Miss Villers, “and I thank you, and Sir David
Brewster, for the lecture; and now,” continued the lady, “how will you
explain the circumstance of my name having been so audibly pronounced,
and from a spot which made it impossible that it should have come from
any human being?”
“It was the solitary spirit of the dell,” said Mr. Seymour, with a
smile; “a rural spirit who is disposed to become very loquacious
whenever the repose of her habitation is disturbed. I can assure you,”
added he, “that you are not the first person whom her gambols have
surprised and terrified in the shades of evening. I presume you have
discovered that I allude to that unseen musician of the air--ECHO.”
“Indeed, Mr. Seymour, the sound could not have been the effect of an
echo, for I never spoke,” replied Miss Villers.
“Very likely, but I happen to know that Mrs. Seymour called you by name
at the orchard gate.”
“Nor will that explain it,” observed Miss Villers, “for in that case I
must certainly have heard her, whereas the sound came in a very
different direction, from the inaccessible rocks of sandstone.”
“Young lady,” said Mr. Seymour, “you must forgive me for telling you
that your philosophy is at fault. It is as possible to hear an echo,
without recognising the direct sound which produced it, as it is for
two persons to be so placed as to see each other in a looking-glass,
although objects might obstruct the direct view of themselves. Did you
never walk between an irregular wall and a row of houses, or along a
valley intercepted by houses during the ringing of a peal of bells?
Nothing is more common under such circumstances, for the sound instead
of arriving at the ear, in its true direction, to be reflected in one
that is opposite to it;--now before we quit the subject of optical
illusion, let me relate an incident which occurred to myself. I presume
you are all acquainted with the appearance in the grass, called a
_Fairy-ring_?”
“To be sure,” said Tom, “a very dark circle of grass, around which
there is generally a ring that looks as if the ground had been burnt.”
“Very well,--and we are now satisfied that this appearance is the
consequence of the growth and decay of certain fungi(47), although the
common people still believe that the ring is produced by the gambols of
fairies--now then for my story. It was on a moonlight night, last
August, when strolling along a neighbouring meadow, enjoying the
beauties of the evening, that I met a young farmer, an intelligent
person, although a little inclined to a belief in the marvellous, who,
on approaching with a hasty step, thus accosted me;--‘You have often
ridiculed my belief in fairies, and of their being the cause of those
rings which go by their name; you may now, if you please, satisfy
yourself of their reality, if you will only return with me to the elm
close, which, as you know, abounds with fairy-rings. Within the last
few minutes I have actually seen them at their gambols under the great
elm; they are, sir, tiny beings which, as far as I could judge at a
distance, cannot be more than a few inches in height; but there they
are, frisking away most merrily: pray, sir, do let us return, and
satisfy yourself as well as me.’--You may readily suppose that I lost
no time in complying with my friend’s request; and sure enough there
they were.”
“What, the fairies!” exclaimed Louisa, in astonishment.
“Have patience, my dear, and you shall hear. I confess,” continued Mr.
Seymour, “that at the first glance, I was almost startled into a belief
in the reality of my friend’s assertion, but on approaching, the Fairy
Queen and her court were changed into a circle of fungi, to which the
shadowy play of the leaves of the neighbouring tree had, in the light
of the moon, given the appearance of a fantastic motion. The illusion,
I will admit, was very extraordinary, and one well calculated to impose
upon the credulous countrymen.”
The young party were much amused by the anecdote, and the vicar took
this opportunity to explain, on natural principles, several
superstitious appearances recorded in ancient legends.
Mr. Seymour now proposed to dedicate an hour to the explanation of the
several toys which owe their action to atmospheric vibration; “I shall
then,” said he, addressing Miss Villers, “be at your service to
interrogate the spirit of the valley; and the children, whom I intend
to accompany us, will be thus better prepared to comprehend the theory
of the echo.”
“Musical instruments, amongst which I include the toys to which I have
alluded, may be classed under three heads:--_stringed_ instruments,
such as the harp, violin, &c.; _wind_ instruments, as the flute and
trumpet; and instruments of _percussion_, as the tabor and drum.”
“And which kind do you consider the most ancient?” asked Miss Villers.
“_Wind_ instruments, madam, most unquestionably,” cried Mr. Twaddleton.
“Diodorus ascribed their invention to the accidental notice of the
whistling of the wind in the reeds, on the banks of the Nile; and the
poet Lucretius maintained a similar opinion.”
“I really, my dear Sir, cannot see any good reason for giving this
preference, in point of antiquity, to wind instruments,” said Mr.
Seymour. “The lyre, or harp, is, surely, as ancient as any instrument
on record. The mythologist ascribes the idea of producing sound by the
vibration of a string, to Apollo; which is said by Censorinus to have
suggested itself to him, on his hearing the twang of the bow of his
sister Diana. With respect to instruments of percussion, it may be
reasonably supposed that the sonorous ringing of hollow bodies, when
struck, must have very soon suggested their invention to mankind; but I
really consider any research into a question of such obscurity as
uninteresting as it must be hopeless; let us rather devote our
attention to the philosophy of these instruments. I have stated that
they may be referred to three principal classes; but I must at the same
time observe that, in some cases, the vibrations of solid bodies are
made to co-operate with those of a given portion of air; for example,
trumpets and various horns may be said to be mixed wind instruments,
since their sound is produced by the joint vibrations of the air and a
solid body; and in certain stringed instruments, as in the violin, the
immediate effect of the strings is increased by means of a
sounding-board, which appears to be agitated by their motion, and to
act more powerfully on the air than the strings could have done alone.”
“I apprehend that this mixture must obtain more or less in all
instruments,” said the vicar.
“Not at all. The flute, flageolet, humming-top, and the cavity of the
mouth in whistling, may be considered as simple wind instruments, in
which the quality of the sound is alone determined by the vibrations of
the air. I have already explained the manner in which the oscillations
of a string excite aërial undulations, and thus produce sound; and you
have seen that the nature of these sounds is determined by the length
and thickness of such strings: the theory equally applies to wind
instruments, in which case, a column of air corresponds with the
string, the volume and length of which determines the sound. In the
harp, the strings are constructed of different lengths and dimensions;
and so, in the _Syrinx_, or _Pan’s pipes_, is the volume of air
adjusted to the respective notes by the size and length of the reeds;
but, in the violin, the lengths of the strings are altered at pleasure
by pressing them down on the finger-board; and, in like manner, the
effective length of the flute is changed by the opening or shutting the
holes made at proper distances in them; the opening of a hole at any
part being the same in effect as if the pipe were cut off a little
beyond it.”
Mr. Seymour and the vicar then entered into a long discussion, with
which it is not our intention to swell our history, or to exhaust the
patience of the reader; we shall, however, with his permission, collect
from the mass some of the more interesting facts, and present them in
as condensed a form as may be consistent with perspicuity. In speaking
of the _Jew’s harp_, a little instrument with which every school-boy is
well acquainted, the vicar stated that its origin was lost in the long
lapse of time; but that it was in very common use throughout Europe,
and more especially in the Netherlands and the Tyrol, where it was the
delight of the peasants and their families. He also said that it was
known in Asia, and that the Greeks of Smyrna called it, in imitation of
its sound, _biambo_. The name by which it is now known, he observed,
was evidently derived from the Jews, who were formerly the great
venders of it, and of other toys throughout Europe, although he stated
that his friend Mr. Prybabel was of opinion that it was a corruption of
_jaw’s_ harp. Mr. Seymour described its construction, and the theory of
its action. [Illustration: Jew’s harp.] It is composed of two parts,
the _body_ and the _tongue_: the former has some resemblance to the
handle of a certain kind of corkscrew; the latter consists of a little
strip of steel, joined to the upper part of the body, and bent at its
extremity, so that the fingers may touch it more readily. This tongue,
or elastic plate, produces, in itself, only a sound which serves as a
drone, although it appears to act like the motion of the bow of a
violin in exciting other sounds, by breaking the current of air from
the mouth, the acuteness or gravity of which will be determined by the
pressure of the lips, and the magnitude of the cavity of the mouth. To
understand, however, this part of its operation, it is necessary that
the reader should become acquainted with the nature and effects of what
have been termed _Resonances, and Reciprocated Vibrations of Columns of
Air_. This property of sounding bodies, which to the ignorant must
appear as an inexplicable species of sympathy, will be more fully
explained in a note(48); at present we shall merely give one or two
examples of its effects. A singer has been known to break into pieces a
large tumbler glass by the power of his voice; and a violin suspended
against a wall may be heard to yield the same notes as those produced
by a performer on a similar instrument in the same room. To produce
such an effect, however, one condition is indispensable, that the body
to be put in vibration must be in unison, or agreeing in pitch, with
the one communicating the sound. Hence the necessity of so adapting the
capacity of the mouth in playing the Jew’s harp, as to make the column
of air which it contains to reciprocate the sound of its tongue. The
subject was agreeably concluded by some anecdotes which were related by
Miss Villers, in proof of the astonishing powers of this little
instrument when directed by the skill of a master. For the sake of
those who may be curious upon this subject we have introduced an
account of two great performers, in an additional note(49). In speaking
of the flute, Mr. Twaddleton took occasion to observe, that its name
was derived from _fluta_,[57] a lamprey, or small Sicilian eel, which
has seven holes on each side; an etymology which will probably be as
new to our readers as it was to ourselves. The children also received
their share of instruction and amusement upon this occasion. Tom, for
the first time, became acquainted with the use of the pea in the
whistle, which, he was told, was to agitate and break the current of
air, and thus to produce a succession of quick vibrations upon which
the acuteness of its sound depended. Louisa exhibited her _whiz-gig_,
which, for the information of the unlearned reader, we may state to
consist of a hollow disc of wood, having an opening in its side, like
that in the humming-top; by the alternate coiling and uncoiling of the
cord upon which it is strung it receives a circular motion, the
rapidity of which produces, by means of its opening, an aërial
vibration that gives a loud ringing sound.
“I should very much like to hear your opinion of that Egyptian wonder,
the statue of Memnon,” said the vicar.
“Its history,” answered Mr. Seymour, “is involved in considerable doubt
and difficulty. Authors of credit agree in stating that it certainly
saluted the rising sun with a musical sound; but doubts are still
entertained as to the cause which produced it, whether it was the
effect of mechanism, or a juggle of the Egyptian priests. An English
traveller, Sir A. Smith, informs us that he visited the statue, and
actually heard the sounds at six o’clock in the morning; but he
believes that they proceeded, not from the figure, but from the
pedestal, and he considers that they may arise from the impulse of the
air upon the stones of which it is constructed. Others have supposed
that the heat of the sun’s rays, concentrated by a mirror, may have
acted upon plates of metal so as to produce the effect. It is not my
intention to argue this point; but I will show you an experiment, by
which you will, I think, be convinced that a statue might easily be
constructed like the Memnon to yield musical sounds by the application
of heat, whether derived from the solar rays, or from any other source.”
[Illustration: The “piece of apparatus” described below.]
Mr. Seymour produced a piece of apparatus, of which we here present the
reader with a sketch. It consists of an oblong block of copper, one
surface of which is flat, the other formed by two planes meeting at an
obtuse angle, and having a groove at the point of junction A. To this
block a handle is affixed.
Mr. Seymour having thus described the form of the instrument, and
stated that its construction was solely directed with a view of making
it oscillate freely on any plain surface, thrust the block in the fire,
and when sufficiently heated, placed it on its angular surface, upon a
flat piece of lead. It immediately began to vibrate, producing at
first, a kind of singing noise, not unlike that of the simmering of a
teakettle, but the vibrations became more and more rapid until a
distinct musical sound was produced, which from time to time varied in
its pitch, and gave rise to an effect scarcely inferior to that of the
Eolian harp.
“How extremely beautiful!” said Miss Villers.
“And how admirably does it illustrate the theory of musical sounds,”
observed Mr. Seymour. “We have here, you perceive, a series of impulses
communicated to our ears by the air, at first in slow succession, and
by degrees more and more rapidly; at first we hear a rattling noise,
then a low murmur, and then a hum, which by degrees acquires the
character of a musical note, rising higher and higher in acuteness. It
is evident, therefore, from this experiment alone, by showing the
correspondence which exists between the pitch of the note and the
rapidity of the succession of the vibrations, that our sensation of the
different pitches of musical notes originates in the different
rapidities with which their impulses are communicated to our ears.”
“Pray explain to us the manner in which the block of metal is thus made
to vibrate,” said Miss Villers.
“It depends,” replied Mr. Seymour, “upon the alternate contraction of
the two opposite edges of the metal from the loss of heat; one of the
edges coming in contact with the cold lead contracts, and by destroying
the balance of the block, causes its opposite edge to come into contact
with the lead, and to undergo the same change; and it is by this
alternate action that a rapid vibration is produced, occasioning, as
you will now readily understand, the musical sounds you have just
heard.”
The lecture having been concluded, Mrs. Seymour proposed that the party
should, at once, proceed to the valley, but the vicar suggested the
propriety of first explaining to the children the principle upon which
the echo depended.
Mr. Seymour concurred in this opinion, and immediately afforded the
following explanation:--“An echo is nothing more than a reflected
sound. When the aërial vibrations strike against any obstacle of
sufficient magnitude, they are reflected back to the ear, and produce a
repetition of the sound, which will appear to proceed from the point
whence they are reflected, so that the apparent direction of the voice
becomes completely changed by an echo. A considerable extent of level
wall will sometimes produce it in great perfection; for a smooth
surface reflects sounds much better than a rough one: but the
circumstance which, perhaps, contributes more than any other to the
perfection of an echo, is the form of the reflecting surface; a convex
surface is a very bad reflector of sound, a flat one reflects very
well, but a small degree of concavity is the form best adapted to the
purpose.”
“I believe,” observed the vicar, “that fluid bodies will also, under
certain circumstances, so reflect sound as to produce echoes.”
“Undoubtedly. The surface of water, especially at the bottom of a well;
and sometimes even clouds will produce this effect.”
“Do you mean to say, papa,” asked Tom, “that sound is reflected from an
obstacle to the ear, in the same manner as my ball is reflected after
striking the wall?”
“Certainly: supposing, of course, that your ball is perfectly elastic;
and in that case, you no doubt remember the direction it will follow.”
“It will always make the angle of _reflection_ equal to the angle of
_incidence_,”[58] said Tom.
“Undoubtedly; and so it is with sound, since air, as you know, is
perfectly elastic. If, therefore, the vibrations fall perpendicularly
on the obstacle, they are reflected back in the same line; if
obliquely, the sound returns obliquely in the opposite direction, the
angle of reflection being equal to that of incidence. You will,
therefore, readily perceive,” continued Mr. Seymour, addressing his
conversation more particularly to Miss Villers, “that a person situated
at an appropriate angle may hear an echo, as it is returned from the
reflecting surface, without hearing the original sound which produced
it. M. Genefay has described, as existing near Rouen, a curious oblique
echo which is not heard by the person who emits the sound. A person who
sings hears only his own voice, while those who listen hear only the
echo.”
“As a smooth and concave surface is capable of producing an echo, how
does it happen that we so rarely meet with one in a room?” asked Louisa.
“Echoes, my dear, are, in fact, produced in every room, by the
reverberation of sound from its walls; but on account of the velocity
with which it travels, they are imperceptible in small chambers,
because the sound occupies no sensible period of time in moving from
the mouth to the walls, and in returning back to the ear again,
consequently the original sound and its echo become so blended and
incorporated, as to appear but one sound. As the dimensions of the
apartment increase, the defect will increase with it; and, in buildings
for music or public speaking, it is often highly inconvenient, and
difficult of prevention. Breaking the surface, or rendering it uneven
by mouldings and ornaments, appears to be the most effectual method of
curing the evil.”
“I perceive then, papa, that in order to produce a perfect echo, the
person who speaks must be at a considerable distance from the obstacle
that reflects the sound,” said Louisa.
“It cannot be otherwise,” replied her father; “and if you will only
consider the rate at which sound travels, you will readily understand
the necessity of such an arrangement. In order to produce a distinct
echo of one syllable, or of a single sound, the reflecting obstacle
must be at least 70 feet from the sound, so that it may have to pass
through a distance of 70 feet to get to the reflector, and 70 more to
return to the ear, making a total passage of 140 feet, which it will
accomplish in rather less than one-eighth of a second; a period of time
so small, that, if it were diminished, it is evident the echo must be
assimilated with the sound itself.”
“But the echo in the valley,” observed Mrs. Seymour, “will repeat four
or five syllables.”
“Undoubtedly. If we make the experiment at a sufficient distance from
the sandstone rocks which act as the reflector.”
“It would appear, then, that the farther the reflecting object is off,
the greater number of syllables will the echo repeat; and I should
think that this fact might enable us to compute the distance of the
reflector,” said Mrs. Seymour.
“In a moderate way of speaking, about three and a half syllables are
pronounced in one second, or seven syllables in two seconds; when an
echo, therefore, repeats seven syllables, we may infer that the
reflecting object is 1142 feet distant.”
“But, my dear Mr. Seymour, this must surely depend upon the nature of
the syllables,” said the vicar. “Pray excuse the interruption; but you
will admit that there must exist a great difference between the echo of
dactyles and spondees. Suppose an echo should be able to return ten
syllables; thus--
‘Tityre, tu patulæ recubans--’
I will be bound for it, that if you were to try its powers in slow
heavy spondees, as _monstrum horrendum_, a return of not more than four
or five syllables could be observed.”
“I will not dispute that point,” said Mr. Seymour.
Louisa here remarked that she had often heard of some very
extraordinary echoes in different parts of the world, to which her
father had not alluded; she mentioned, for instance, those which are
said to repeat the same sound several times in succession.
“From the explanation which I have already given of the nature of
echoes,” said Mr. Seymour, “it will be easily conceived that a vast
variety of effects may be produced by varying the form, the shape, the
distance, and the number of reflecting surfaces: and hence we hear of
various surprising echoes in different places. It is not difficult, for
instance, to understand the nature of compound, or tautological echoes;
in which case the expression of one _ha_ will appear like a laughter.
Addison mentions an extraordinary instance of this kind near Milan,
which will return the sound of a pistol fifty-six times.”
“I have understood that the echoes on the lakes of Killarney are of
this multiplied description,” said the vicar.
“They are particularly calculated to produce reflections of sound, from
the height of the mountains, and the expanse of water,” replied Mr.
Seymour, “which latter circumstance always assists the conveyance of
reflected, as well as direct sound. I believe that there is a certain
spot on the shore of Ross island, where the sound of a bugle produces
an echo which far exceeds any other to be met with amongst the lakes;
the first echo is returned from the castle, the second from the ruined
church of Aghadoe, the third from Mangerton, and afterwards innumerable
reverberations are distinguished, which, like the faded brilliancy of
an extremely multiplied reflection, are lost by distance and
repetition.”
“There is an admirable echo,” said the vicar, “behind my old college at
Cambridge; and often have I, while walking on the road to Chesterton,
on a calm evening, distinctly heard twelve repetitions of the voice.
Lord Bacon, if I remember correctly, mentions an instance of sixteen,
in some ruined church near Paris.”
“It was in the church of Pont-Charenton, on the Seine,” replied Mr.
Seymour; “in which place that great philosopher discovered the
inability of an echo to return the letter S, for having pronounced the
word _satan_, the echo replied _va-t-en_, which in French signifies
_away_; from which circumstance, the Parisians concluded, that some
guardian spirit prevented the walls of the sacred edifice from
pronouncing the name of _satan_.”
“And will not an echo repeat the letter S?” asked Louisa.
“Not always,” answered her father; “the hissing or sibilant noise of
the letter, when at the commencement of a word, is generally lost,
unless the echo be extremely perfect.”
The party now set off on their excursion to the valley. Mr. Seymour
disposed them in such situations as were best calculated to display the
powers of the echo, and to illustrate the several effects which he had
endeavoured to explain. The vicar performed his experiment with
dactyles and spondees, and was highly gratified to find that their
results proved, in a most satisfactory manner, the correctness of his
conjecture. The attention of Miss Villers was particularly directed to
the effect of the voice of Mrs. Seymour from the orchard gate, and
which, she said, convinced her that the sound she had heard on the
preceding evening must have arisen from the cause assigned to it.
After the party had fairly tired themselves by their converse with the
airy and unsubstantial being, they descended to the sandstone rocks,
which Mr. Seymour pointed out as the local habitation of the solitary
spirit. These were duly examined by Louisa and Tom, and their operation
as a reflecting screen was pointed out to them by their father. They
now returned into the geological temple; its singularly beautiful
pillars very naturally attracted the attention of Miss Villers, and she
expressed a wish that Mr. Seymour should describe the plan of their
construction; for it was very evident, as she said, from the
disposition of the specimens, that the arrangements had been directed
with some view to geological illustration. Mr. Seymour felt gratified
by this request, and promised to comply with her wishes, as soon as he
had finished the investigation of those laws by which the reflection of
sound was governed.
“Why, bless me!” exclaimed the vicar, “the revels of our airy companion
are ended; and I maintain, that nothing can be more appropriate than
the consideration of the objects for which Miss Villers has expressed
so much interest. In truth, the history of Echo is classically
associated with that of geology: by diving into the recesses of the
rock, we do but pursue her descent from air to earth; for you, no
doubt, remember that after she had been deprived of her loquacity by
Juno, she became enamoured of Narcissus, pined away, and was
transformed into stone.”[59]
“I cannot but admire the ingenuity with which you embellish every
subject with classical decorations,” replied Mr. Seymour. “You,
however, must well know that I require no such allurement on the
present occasion. I shall be most willing to afford Miss Villers the
information she requires, as soon as I have explained to my young
pupils the principle of the whispering gallery in St. Paul’s; as well
as some recreations which are indebted for their effects to the
reflection of sound.”
“I ought to apologise for the interruption I have occasioned,” said
Miss Villers; “but I was not, until this moment, aware of the extent to
which you intended to carry your illustrations.”
Mr. Seymour commenced with the subject of the “whispering gallery,” at
the foot of the dome of St. Paul’s cathedral; and in order to render
intelligible the manner in which sound is concentrated, and thereby
magnified in that hollow hemisphere, he produced a diagram, of which
the annexed cut is a copy.
[Illustration: Diagram of sound magnification.]
He explained it as follows:--
“M shows the situation of the mouth of the speaker, and E that of the
ear of the hearer. Now, since sound radiates in all directions, a part
of it will proceed directly from M to E, while other rays of it will
proceed from M to _u_, and from M to _z_, &c.; but the ray that
impinges upon _u_ will be reflected to E, while that which first
touches _z_ will be reflected to _y_, and from thence to E; and so of
all intermediate rays, which are omitted in the figure, to avoid
confusion. It is evident, therefore, that the sound at E will be much
stronger than if it had proceeded immediately from M without the
assistance of the dome; for, in that case, the rays at _z_ and _u_
would have proceeded in straight lines, and consequently could never
have arrived at the point E.”
“I have understood that a similar effect may be witnessed in the stone
recesses on Westminster-bridge,” said the vicar.
“That is the fact,” replied Mr. Seymour. “The recesses to which you
allude are semi-domes; and if a person whispers in the focus of one of
them, he will be distinctly heard by another stationed in the focus of
the opposite one. Two inanimate busts may be thus made to appear as if
holding a conversation, by placing them in the foci of two large
concave mirrors constructed of pasteboard, and arranged opposite to
each other; when a whisper uttered to the one will seem to proceed from
the other by the reflection of sound.”
Mr. Seymour now removed a shell from a group of corallines which
decorated a part of the temple, and desired Tom to place it to his ear.
“I hear a noise which appears to me to resemble that of the sea,” cried
Tom.
“Ay,” said the vicar, “and there is a popular belief that it is the
murmur of the sea, which the shell actually sends forth, betraying, as
it were, its marine origin.”
“And what produces the sound?” inquired Louisa.
“The interior of the shell merely concentrates, and thus magnifies the
sounds around us, so as to render them audible: a goblet applied to the
ear will be found to produce the same effect,” replied her father.
“I suppose it is upon the same principle that the speaking-trumpet is
made to convey sound to a distance,” remarked Louisa.
“Since sound radiates in all directions, it follows that, if such
radiation be prevented by confining it in tubes, it may be carried to a
great distance with very little diminution of its effect; and hence the
use and application of those trumpets, or tin speaking-pipes, which are
now commonly used for conveying intelligence from one part of a house
to another. The trumpet used by deaf persons acts on the same
principle; but as the voice enters the trumpet at the large instead of
the small end of the instrument, it is not so much confined, nor is the
sound so much increased.”
“I believe,” said Mrs. Seymour; “that the experiment exhibited some
time since in London under the title of the _Invisible Girl_, and which
excited such general curiosity, was discovered to depend upon an
arrangement of this kind.”
“I expected that you would allude to that exhibition,” said Mr.
Seymour; “and as I was anxious to provide my young pupils with some new
amusement, as a reward for their industry, I have directed Tom Plank to
construct the necessary apparatus for exhibiting and explaining the
deception. On our return to the lodge, I have no doubt we shall find
that every arrangement for the performance has been completed.”
Miss Villers was now gratified by a view of the more interesting
specimens in the geological temple. Mr. Seymour also explained the
design of the pillars which had so greatly excited her curiosity.
On the return of the party, Mr. Seymour found, as he had anticipated,
that the necessary apparatus for the experiment of the “Invisible
Girl!” had been duly arranged, and that Tom Plank was in attendance to
afford any assistance which might be farther required. We shall proceed
to describe all the visible mechanism, as it appeared to the children
on entering Mr. Seymour’s study, and of which we here present the
reader with a perspective sketch.
[Illustration: Apparatus for Invisible Girl experiment.]
It consisted of a wooden frame, not very unlike a bedstead, having four
upright posts, _a a a a_, and a cross-rail at top and bottom to
strengthen them. The frame thus constructed stood upon a low table, and
from the top of each of the four pillars sprang four bent brass wires,
which converged to the point _c_. From these wires a hollow copper ball
was suspended by ribands, so as to cut off all possible communication
with the frame. The globe was supposed to contain the invisible being,
as the voice apparently proceeded from the interior of it; and for this
purpose it was equipped with the mouths of four trumpets, placed around
it in a horizontal direction, and at right angles to each other, as
shown in the annexed section, in which the globe is represented in the
centre; _d d d d_ are the trumpets, and _b b b b_ the frame surrounding
them, at the distance of about half an inch from their mouths. Such as
we have described was the apparatus, which had been constructed under
the direction of Mr. Seymour, who informed the party that, if any of
them would ask a question of his little fairy, and direct the voice
into one of the trumpets, an answer would immediately be returned from
the ball.
[Illustration: Top of the Invisible Girl apparatus.]
“Let me interrogate her,” exclaimed Louisa, as she advanced towards the
railing. “Tell me, mysterious being, the name of the person who now
addresses you.”
“Miss Louisa Seymour,” answered a voice sufficiently audible to Louisa,
whose ear was near the mouth of the trumpet, and yet so distant and
feeble, that it appeared as if coming from a very diminutive being, and
thus heightened the deception. Each of the party successively asked
some question; and the surprise of the children may be more easily
imagined than described. Tom examined the ball, the trumpets, and the
framework; but he was unable to discover any clue by which he could
unravel the mystery. At length Mr. Seymour proceeded to the
explanation. He told them that the mechanism owed its effects to the
combined operation of two principles with which they were already
acquainted; the concentration and conveyance of sound by means of a
speaking-pipe, and its reflection from an appropriate surface so as to
change its apparent direction, by producing an artificial echo. He then
showed them the pipe which was concealed in one of the legs of the
frame, and explained in what manner the voice of Tom Plank, who had
been stationed in an adjoining room, was conveyed to the mouth of the
trumpet, and thence reflected to the ear of the observer. By means of
the annexed section, we shall hope to render this subject as
intelligible to our readers, as did Mr. Seymour to his little pupils.
[Illustration: Side view of Invisible Girl apparatus, with secret pipe
shown.]
_b b_ represent two of the legs of the frame, one of which, as well as
half the rail, is made into a tube, the end of which opens immediately
opposite to the centre of the trumpet. This hole is very small, and
concealed by mouldings; the other end communicates by a tin pipe, _p
p_, which passes, in a concealed manner, along the floor of the room,
into an adjoining closet, where the confederate is concealed. It is
evident that any sound, directed into the mouth of the trumpet, will be
immediately reflected back to the orifice of the tube, and distinctly
heard by a person who places his ear to the mouth of the funnel _m_;
while the answer returned by him, travelling along the tin funnel, _p
p_, will issue from its concealed orifice, and striking upon the
concave surface of the trumpet, be returned to the ear as an echo, and
thus appear as if it had proceeded from the interior of the ball.
The vicar observed, “that this deception of the _Invisible Girl_, which
had formerly created so much interest, was little more than the revival
of the old and well-known mechanism of the _speaking bust_, which
consisted of a tube, from the mouth of a bust, leading to a confederate
in an adjoining room, and of another tube to the same place, ending in
the ear of the figure; by the latter of which, a sound whispered in the
ear of the bust was immediately carried to the confederate, who
instantly returned an answer by the other tube, ending in the mouth of
the figure, which therefore appeared to utter it. The Invisible Girl,”
continued the vicar, “evidently only differs from that contrivance in
this single circumstance, that an artificial echo is produced by means
of the trumpet, and thus the sound no longer appears to proceed in its
original direction.”
“Your remark is perfectly correct, my dear vicar,” said Mr. Seymour.
Tom Plank, with an air of self-satisfaction, at this moment emerged
from his retreat, and enquired whether his performance had not met with
the approbation of his employer.
“Gentlemen,” said Tom Plank, “as I am now fully satisfied that any plan
of propelling live and dead luggage through funnels can never succeed,
I propose to employ tubes for conveying sounds to a great distance, so
as to do away with the use of telegraphs?”
“Why that plan is more practicable, but less novel, than the one you
have just abandoned,” answered Mr. Seymour. “At the latter end of the
last century, a man of the name of Gautier conceived a method of
transmitting articulate sounds to an immense distance. He proposed the
construction of horizontal tunnels that should widen at their
extremities, by means of which the ticking of a watch might be heard
more distinctly at the distance of two hundred feet than when placed
close to the ear. I think he calculated that a succession of such
tunnels would transmit a verbal message nine hundred miles in an
hour.”(50)
“Only think of that!” ejaculated Tom Plank; “to make a communication
from London to Edinburgh in about twenty-five minutes!”
“True, my friend; but what would you say, were I to suggest a method of
communicating information to any distance without the loss even of a
single second of time.”(51)
“There now,” cried the vicar, “you have supplied Tom Plank with some
fresh barm to set his brains working.”
“He is an indefatigable fellow, I must allow,” said Mr. Seymour.
After this discourse the vicar rose from his seat, and on walking
across the room, the creaking of his shoes excited the attention of Mr.
Seymour, who, with his accustomed gaiety, observed, that “the vicar had
music in his _sole_.”
“Mr. Seymour!” exclaimed Mr. Twaddleton, with a look which we should in
vain endeavour to describe, “the infirmity of my shoes, _crepitus
crepidæ_, is at all events sanctioned by high antiquity; for we are
told by Philostratus, in his Epistles, that Vulcan, being jealous of
Venus, made her creaking shoes, in order that he might hear whenever
she stirred.”
So ludicrous an appeal to antiquity would have overcome Heraclitus
himself, no wonder then that the whole party enjoyed a hearty laugh at
the worthy vicar’s expense.
“Well, Mr. Twaddleton, if, as you say, I have brought down philosophy
to account for the most familiar occurrences, it is but just that I
should return the compliment, by declaring that you are equally
prepared to throw a classical interest around the humblest as well as
the most dignified subject, _à capite usque ad calcem_,” observed Mr.
Seymour.
“Now, Tom, as you have so lately been instructed in the different
sources of sound, do tell your good friend, the vicar, the cause of the
creaking of his shoes,” said his father.
“The dryness of the leather, I suppose,” answered the young philosopher.
“A certain state of dryness is certainly a necessary condition, or else
the cohesion between the inner and outer sole would exclude the air.
Correctly speaking, the creaking depends upon the sudden compression of
the air contained between the two surfaces of leather; just as a sound
is produced by the clapping of the hands by the air thus set in
vibration. Shoes with single soles, therefore, never creak, and by
interposing a piece of oil-silk between the two soles, you will so far
ensure the contact of their surfaces as to obviate the sound,” said Mr.
Seymour.
“That is at all events a piece of practical philosophy worth knowing;
and I shall accordingly instruct my operator, Jerry Styles, upon this
point,” observed the vicar.
“So you see, my dear sir, I am no bad shoemaker, although I have never
yet made a shoe,” said Mr. Seymour.
“To be sure--to be sure,” exclaimed the vicar; “for as Horace has it--
----“Sapiens crepidas sibi nunquam
Nec soleas fecit: Sutor tamen est sapiens.”[60]
“You never made a happier quotation,” exclaimed Mr. Seymour.
“I have only one other remark to make,” continued he, “which the
consideration of this subject has very naturally suggested--that the
various strange sounds, which have from time to time alarmed the
superstitious, may be readily explained upon the simple principles we
have been discussing. I well remember a whole family having been thrown
into a state of terror, by a mysterious sound which regularly recurred
every evening; when it was at length discovered to arise from the
crawling of snails over the window; their slimy surfaces, as they moved
along, produced a friction, which occasioned a vibration of the glass.”
“And I never recall to my recollection, without some degree of terror,”
said the vicar, “the night I passed in an old oaken chamber which had
the reputation of being haunted. A bright fire cheerfully blazed in the
grate as I entered the apartment, and casting its ruddy light around,
in some measure dissipated the prejudice which had been raised to the
disparagement of my dormitory; but awaking in the night, my fire was
out, and a succession of the most extraordinary noises I ever heard
assailed me.”
“All which are easily explicable,” said Mr. Seymour. “The old oaken
materials were expanded by the heat of your fire, and on the apartment
cooling, they again contracted, and gave origin to all the sounds you
describe.”
“How unsparingly does science clip the wings of imagination!” observed
Miss Villers.
The party now dispersed. Miss Villers retired into the drawing-room, to
afford Louisa some musical instruction; the vicar took his departure
for the sake of visiting a sick parishioner; and Major Snapwell to make
arrangements for an important event, with the nature of which the
reader will very shortly be made acquainted.
-----
Footnote 57:
“Murænæ optimæ flutæ sunt in Sicilia.” _Varr. R. R._ ii. 6. 2.
Footnote 58:
The reader is requested to turn to page 174; for all that is there
said respecting the principle of _reflected_ motion will apply to the
theory of the echo.
Footnote 59:
Ovid’s Metamorph. 3. 358.
Footnote 60:
“For though the wise nor shoes nor slippers made,
He’s yet a skilful shoemaker by trade.”
_Hor. Sat. 3 Lib. 1._
------------------------------------------------------------------------
CHAPTER XVII.
_An interesting communication, from which the reader may learn that
the most important events are not those which absorb the
greatest portion of time in their recital.--Major Snapwell
communicates to Mr. Seymour and the Vicar, his determination to
celebrate the marriage of his nephew by a fête at Osterly
Park.--An antiquarian discussion of grave importance.--An
interview with Ned Hopkins, during which the wit displayed both
cunning and humour.--The Thaumatrope.--Its improved
construction.--Philosophy of its action.--Another optical
toy.--The nature of Optical Spectra illustrated and
explained.--The Spectral Cross of Constantine._
For some time had Major Snapwell been occupied in making arrangements
for an event, which he hailed not only as the accomplishment of his
most ardent wishes, but as the guarantee of his future happiness. We
did not think it right to impart this secret to our readers, until the
period should arrive when, in conformity with the usage of the world,
the subject might be referred to without reserve or impropriety. To
such a period has our history arrived, and we shall therefore at once
communicate the whole story, by relating the substance of a
conversation which took place between Major Snapwell and the Vicar, in
the presence of Mr. and Mrs. Seymour, in the library of Overton Lodge.
“Your hand, my dearest friend! your hand, and with it the
congratulations of your heart,” exclaimed the Major, as he approached
Mr. Twaddleton; “our friends here,” added he, as he bowed to Mr. and
Mrs. Seymour, “are already acquainted with the proposed union between
my worthy nephew, Henry Beecham, and the charming Isabella Villers; and
may Heaven shed the dew of its blessing upon them!”
“Amen!” ejaculated the vicar.
“Well, sir, I am most anxious that the ceremony should take place at
Overton, and that you should officiate upon the occasion.”
“Most cheerfully shall I comply with your request; ‘_connubio jungam
stabili_,’ as the immortal poet has it,” was the vicar’s reply.
“I have also to inform you,” continued the major, “that it is my wish
to diffuse a portion of that delight, which this event will impart to
me, over the neighbourhood in which I shall probably pass the days that
may be yet spared to me; listen, therefore, to the plan which I have
devised for carrying this into effect. I design to give a public
entertainment, upon a plan as novel as its scale shall be extensive; it
shall not be a mere blaze of the spirits, but the recreation of the
mind, and the jubilee of reason.”
“An entertainment!” muttered the vicar, whose countenance afforded any
thing but encouragement to such a scheme.
“Ay, vicar; an entertainment which shall be conducted with every regard
to ancient usage, and classical correctness,” said the major, as he
cast a sly glance at Mr. Seymour.
The countenance of the vicar brightened; and he begged his worthy
friend to be more explicit, and to state the nature of his intended
fête.
“You already know that this boy of mine is shortly to conduct Miss
Villers to the temple of Hymen; I would seize that happy occasion for
giving a rural fête, in my park, to the inhabitants of Overton and its
neighbourhood; and, as there are no less than three events which I am
anxious to celebrate, I propose that this same fête shall be continued
through three successive days. On the first shall be commemorated the
providential escape of my nephew from shipwreck; on the second, his
marriage; and on the third, my purchase and occupation of Osterley
Park--What think you of my plan?”
“Why, truly, it would admit of much appropriate pageantry, and the
arrangement is, doubtless, countenanced by classical authority.
Augustus triumphed three days, for the purpose of commemorating three
great events; the first of which was the defeat of the Pannonians and
Dalmatii; the second, the battle of Actium; and the third, the
reduction of Egypt. Then, again, we have the _Ludi Magni_ of the
Romans, and the solemn Athenian feast, _Apaturia_, which lasted during
three days; and above all, the Secular Games, which were continued
through the same period. In the face of such authorities, it would
certainly ill become me to offer any objection; although, as vicar of
the parish, I cannot conscientiously close my eyes against the evils
which might possibly arise from such protracted revelry. I would,
therefore, with submission, propose that the three events to which you
allude, should be celebrated by three distinct festivals on one and the
same day.”
The major saw plainly that the vicar might be made to approve of, or
dissent from, any plan, by the dexterous use of classical authority; he
therefore determined to use it as a talisman for the accomplishment of
his purpose.
“I like your proposition,” replied the major, “but I greatly fear that
you will not be able to support it by any classical authority; and
remember, that every thing must be conducted in the strictest
accordance with ancient usage.”
“I respect your intention,” answered the vicar, “and will immediately
search the writings of Lipsius for a precedent; an author who has
collected fifteen laws of the Roman entertainments; or, perhaps, the
Pandects of Franciscus Modius, who has so ably treated of nuptial
ceremonies, will furnish the desired information.”
Mr. Seymour here interrupted the conversation, by enquiring of the
major the plan of those amusements which he proposed to provide.
“I will convert the elm meadow at Osterley Park into a fair,” replied
the major, “wherein every species of amusement shall be exhibited: I
will engage that vagabond Punch, who, like a snail, travels about the
country with his house at his back, to display his hereditary wit, and
mimic drolleries; tumblers, rope-dancers, conjurors, fire-eaters, and,
in short, the whole merry train of Comus, shall be pressed into our
service. After these exhibitions, the company may weave the mazy dance,
for platforms shall be erected for their accommodation; I will arrange
orchestras for music, and ornamented tents for refreshments. The
vicar,” observed the major, with an arch smile, “shall open the ball
with the bride.”
“Had I numbered a few olympiads less, major, I might not have declined
so flattering a distinction,” replied Mr. Twaddleton, evidently not
displeased with the compliment.
“Find some classical authority for the measure, and let your age
sanction the propriety of my proposal,” said the major.
“Your suggestion merits attention,--let me see--I have it, major.
Socrates learned to dance very late in life, and Cato, with all his
severity of manners, disdained not, at the age of sixty, to practise
it. I will, therefore, comply with your desire, and certainly lead the
bride down the first dance.”
“The canal,” continued the major, “shall, for the first time, float the
proud emblems of British glory on its glassy bosom; and when the shades
of evening fall, my Lilliputian ships shall engage--such cannonading!
such nautical evolutions!! Mr. Seymour.”
“How charming! how very delightful!” exclaimed Louisa and Fanny: “but
pray, papa, do allow Tom to return from school to witness all these
amusements.”
“Fear not,” said the major; “I shall make that a condition; and I trust
your papa will not refuse the request.”
“Certainly not,” replied the father; “I shall be anxious to seize so
favourable an opportunity for explaining to my children the various
tricks they will witness, and the machinery by which the numerous
deceptions will be accomplished; thus shall I convert that which, to
the common eye, will appear as a scene of idle revelry, into a school
of philosophy, and in accordance with my favourite plan, ‘turn sport
into science.’”
“Upon my word, Mr. Seymour, you are a perfect alchymist, and extract
gold from every thing you touch; you have already derived scientific
information from the most miscellaneous and trifling amusements, and
will, no doubt, upon this occasion, convert our very pies and puddings
into instruments of instruction; thus verifying the old adage, ‘that
there is reason in roasting of eggs,’” said the major.
“I perceive that the major is not aware of the philosophy which
suggested that adage,” observed the vicar.
“Nor am I,” said Mr. Seymour, “and therefore pray enlighten us upon
that point.”
“You doubtless know that there is a little air bag at the large end of
every egg, called the _folliculus aeris_, and which, as we are told, is
designed to furnish a supply of air to the growing chick; if,
therefore, an egg be exposed to the temperature of hot embers, this air
will be suddenly expanded, the shell burst, and its contents scattered
into the ashes. To prevent such an occurrence, the careful house-wife
pricks the blunt end of the shell with a needle, so as to allow the
expanded air to escape, and thus to prevent the accident I have just
explained; from which it appears that there is reason, or philosophy,
in roasting an egg.”
“Capital, upon my word!” exclaimed Mr. Seymour.
“Well, but, papa, we have interrupted the major in his delightful
description; he had not concluded the account of his proposed fête,”
said Louisa.
“Pray go on,” cried Fanny: “let me see, where did you leave off? Oh, I
remember, you were interrupted in a temporary tent, which I hope you
intend to decorate with garlands.”
“Leave all that to the vicar, young lady; he will, no doubt, display
his classical taste in the emblematical appointments.”
“I shall terminate the festivities of the day by a grand display of
fire-works; the arrangements of which will necessarily fall under my
own more immediate direction. The vicar,” added the major, “will
perhaps allow me to proclaim him as master of the revels; for he is, as
we all well know, deeply versed in ancient customs, and I am especially
anxious that every department should be conducted with classical taste.”
“I willingly accept the office,” said Mr. Twaddleton, with a gracious
smile, “since there is authority for my acquiescence. The Romans, in
their entertainments, usually appointed a person whom they styled king,
and held responsible upon such occasions. I accept it also, on a
different ground; that my presence may check the enthusiasm of the
people, and restrain the hilarity of the evening within the boundary of
rational decorum.”
“If in the arrangement of your banquet, my assistance can prove of any
service, command me,” said Mrs. Seymour.
“Believe me sincere, my dear madam, when I say, that the kind manner in
which you receive my plan, and offer to promote its execution, affords
me the highest gratification; if I decline your services, it is only
from a fear of usurping the sovereignty of our master of the
ceremonies,” replied the major.
“What! am I to descend into the lower regions, and hold converse with
your ancient Sibyl, the cook? Would you call upon me to marshal the
dishes? Am I, at once, to perform the offices of ‘_Dapifer_,’
‘_Lardrenius_,’ ‘_Magister Coquorum_,’ and ‘_Prægustator_?’” cried the
horrified vicar.
“Have I not declared that every part of my entertainment shall be
strictly classical? and ought not each dish to convey some moral
device, some allegorical design? Are we to feed with as little
discrimination as the dogs that devoured the sacred Apis?”
The knowledge which the reader must have already collected of Mr.
Twaddleton’s character will have satisfied him that, in every action of
his life, he was more or less influenced by the spell of ancient
authority; but we doubt whether he may not yet have to learn the extent
to which the reverend gentleman carried this enthusiasm. We shall,
accordingly, beg to state a few instances, which will serve to
illustrate this circumstance. Be it known, then, that the very first
act which announced the preferment of the Reverend Peter Twaddleton to
the dignity of Vicar of Overton, was not, as some might suppose, an
increased rate of compensation for the tithes; nor was it a rate levied
for the repairs of his house; but the removal of the vane from the
spire of the church, which, as it consisted of a simple cross piece of
iron, seemed to the vicar’s imagination to be wriggling about, without
any consciousness of its ancient origin and dignity. He therefore, at
his own expense, replaced it by the figure of a cock, which he caused
to be duly executed after an authentic model. It will be remembered
that the crowing of the cock warned Peter; for which reason the monks
first placed the figure of that bird on their churches, as an emblem to
call the people to prayers; and, since the image was made to revolve
with the wind, it soon acquired the name of the _weathercock_. With
respect to the arrangement of his table, he displayed an equal
veneration for ancient forms. He perpetuated the use of the wassail
bowl, which was scrupulously prepared with apples and ale, according to
the most orthodox receipt. His mince-pies at Christmas were fabricated
with the same inflexible adherence to ancient authority; he maintained
that the introduction of meat into their composition was a scandalous
heresy; that the choicest productions of the East ought alone to be
admitted, since the custom was originally intended to allegorise the
offerings made by the wise men who came from afar to worship, bringing
_spices_, &c. He was also as critical with respect to the _shape_, as
he was with regard to the _composition_ of these dainty inventions; he
insisted upon the ancient or coffin shape, which he stated to have been
in imitation of the cratch, or manger, wherein the infant Jesus had
lain. His table was, with the same antiquarian correctness, punctually
supplied at Easter with a gammon of bacon; a custom, which would,
perhaps, have been more honoured in the breach than in the observance,
since it was evidently founded on the abhorrence our forefathers
thought proper to express towards the Jews, at the season of
commemorating the resurrection.[61] The idea was in direct opposition
to the liberal sentiments of the vicar, but, being an ancient custom,
he never ventured to question its propriety. In like manner, his
tranquillity would have been sadly disturbed, had Annette ever
forgotten the _pancakes_ on Shrove-Tuesday; for he was decidedly of
opinion that it was a dish which had derived its origin from the
heathen Fornacalia, a festival instituted by Numa,[62] in honour of the
goddess Fornax; and was intended to commemorate the making of bread
before the invention of ovens. Upon the subject of cross-buns he
displayed great profundity; he observed, that the word _bun_ was
derived from _boun_, a species of sacred bread described by Hesychius,
and which was anciently offered to the gods; in support of which
opinion he quoted Julius Pollux and Diogenes Laertius; nor did he
relinquish the subject, until he had ably descanted upon the address
with which heathen customs had been, as it were, naturalized, and
perpetuated as Christian observances. The _boun_, he would say, lost
its idolatrous impurity by receiving the sign of the cross; in the same
manner that Druidical idols, and _stones erect_, by having crosses cut
upon them, continued to receive a justifiable reverence, even as late
as the seventh century.
In short, the extent to which our excellent but eccentric vicar was
carried, on such occasions, can scarcely be credited, except by those
who are acquainted with the extravagant whimsies of a genuine
antiquary. We have never contemplated this part of his character
without congratulating the rising generation at Overton on the
circumstance of the offices of village schoolmaster and vicar of the
parish not having centered in the same individual; for we have not the
shadow of a doubt, so great was his veneration for ancient usages, but
he would have whipped up every child within his jurisdiction, on the
morning of Childermas-day, or that of the Holy Innocents, as we are
informed was the ancient custom, “in order that the memorial of Herod’s
murder of the Innocents might stick the closer.” On the other hand, he
would readily have forgiven any offence had the boy only cited a few
lines from a favourite classic; for often had he been heard to relate
with much satisfaction the well-known story of the Athenian Captives,
whose lives were preserved in Sicily, from their being able to repeat
portions of the dramas of Euripides. Whether, in spite of the censure
and remonstrance of St. Austin, he would have ventured to continue the
half-holiday on a Thursday, it is difficult to say; although the high
antiquity of a custom originally established in honour of Jupiter,
would, doubtless, have produced its influence upon the judgment of the
antiquary.
One more anecdote, and we trust our illustrations of the vicar’s
character will be perfect. The reader will remember, that to Dr.
Doseall, the renowned Esculapius of the village, he had given the title
of _Polyphemus_: this might appear inconsistent with his acknowledged
kindness, and we are therefore bound to state his justification. “Was
it not,” he asked, “a notorious custom in Athens to give nicknames
expressive of personal peculiarities? Do we not learn from
Aristophanes, that the poet Theognis, from the deficient warmth of his
compositions, went by the name of _Snow_? and moreover, did not the
Athenians, as a body, from their passion for news, and their habit of
swallowing open-mouthed the flying rumours of the day, receive the
soubriquet of _Gapers_, just as the London inhabitants of the present
day rejoice in that of _Cockneys_?”
We have thought it right to relate these few anecdotes, in order to
vindicate the propriety of the major’s choice, and to convince the
reader that a better qualified master of the ceremonies could not
possibly have been provided. Having, therefore, paid this homage to the
judgment of the major, and to the antiquarian lore of the vicar, we
shall return to the party, whom we had rather abruptly quitted, and
continue our relation of the conversation which followed.
“So, then, you have determined that the vicar shall superintend the
banquet,” said Mrs. Seymour. “There is, however, one part of the
ceremony which I shall certainly not feel disposed to resign into his
hands, the ordering and disposition of the bridal cakes; the genius of
Gunter shall be invoked to produce one of the most triumphant specimens
of his art.”
“Psha, nonsense! you surely would not countenance that ice-clad
mountain, through whose dark regions the demon of indigestion holds
undisputed sway.”
“Why, zounds, vicar, do you expect me to submit to such vagaries?--a
wedding without a cake!--it cannot be tolerated. I shall next hear of
an English feast without roast-beef,” vociferated the major.
“You shall, doubtless, have your cake; but let it be the true Roman
bride-cake, made after the receipt which Cato has given in his work,
_De Re Rustica_, chapter 121. You must be aware, Mr. Seymour, that the
_mustacea_ of the Romans, the species of cake used at weddings,
consisted of meal, aniseed, cummin, and several other aromatic
ingredients.”
“And do you seriously believe that any of us will swallow such a
medicated farrago?” said the major.
“The unenlightened may, perhaps, refuse it; and should the children
prefer your modern combination, they might stand excused, since
classical inspiration rarely descends upon a boy, until he has
construed a Greek chorus,” observed the vicar.
“Were I to swallow a grain of it,” said Mrs. Seymour, “I verily believe
I should be ill for a week.”
“Mere prejudice, madam; the object of the _mustacea_ was actually to
remove or prevent the indigestion which might be occasioned by eating
too copiously at the marriage entertainment; and it must, I think, be
acknowledged that the compound was better adapted for such a purpose
than the modern bride-cake, to which it gave origin.”
“With respect to the _roast-beef_, to which the major has just
alluded,” continued the vicar, “I shall only observe, that it was not
until the reign of Henry VIII. that it appears to have taken its part
in the formation of our national character.”
“I would beg to enquire to whom the selection and arrangement of the
comic entertainments are to be intrusted. Unless the major should have
already found a competent person, I think I can recommend to his notice
an individual who is eminently qualified for the duties,” said Mr.
Seymour.
“I am, at this moment, in quest of such a director,” said the major.
“Ned Hopkins, then, who has for some time past taken up his abode at
our village alehouse, is the very person, of all others, whom you seek.
I have no doubt that for a trifling consideration he will undertake the
office; and I feel equally confident that he will execute its duties to
your satisfaction.”
“Ned Hopkins!” exclaimed the vicar, with some surprise.
“To be sure; and who better understands the trim of those itinerant
sons of Comus? Was not his father a mountebank doctor, and a professor
of the art of legerdemain?”
“I value not Ned Hopkins the less on that account; the immortal Virgil
was the son of a servant, or assistant, to a wandering astrologer, or
‘Medicus Magus,’ as Juvenal has it; and the mother of Euripides was a
cabbage-woman, for which Aristophanes so unjustifiably ridicules him.
But my dislike to Ned Hopkins is founded upon his own dissipated
habits, his disgusting jokes, and Bacchanalian buffoonery.”
“Ay,” continued Mr. Seymour, “and his bad puns, vile quotations, and
hackneyed proverbs; and yet you must confess that, after all, he is a
very clever fellow.”
“Sir,” observed the vicar, “Satan does not usually select a fool as his
ambassador.”
“Upon my word, gentlemen, this must needs be a very amusing fellow; and
you have so far excited my curiosity, as to make me desirous of hearing
something farther of his history and habits,” said the major.
“He is one of those loose spirits,” replied Mr. Seymour, “who live upon
expedients; and measuring their consciences by their wants, derive a
revenue from sources, of which those who jog on quietly through the
beaten paths of life have not the most remote conception. He commenced
his career under the tutelage of the first fire-eater of the day, but
having clumsily scalded his mouth, he lost his reputation, and found it
advisable to seek some other stage for the display of his abilities.
Possessed of a very considerable degree of native humour and caustic
shrewdness, he engaged himself as a ‘mercenary,’ or literary drudge, to
a popular publisher of comic song books, sanguinary murders, magical
magazines, amorous valentines, oracles of health, and plans for the
liquidation of the national debt; which occupations have, as I have
been credibly informed, produced for him during a successful season,
some twenty or thirty pounds in the lawful coin of the realm: but Ned,
like many a great genius, was better pleased with an hour of idleness
than a week of study; and, strange to say, would at any time have
preferred a cup of wine to a bucketful of the finest water from
Helicon; no sooner, therefore, had he collected a few pounds, than he
descended from his high literary station, a lofty garret; and, taking
up his abode at some hedge alehouse, would enjoy a life of happy
leisure, until every particle of that worldly substance which he had
gained by inspiration from above, was gratefully returned to the skies
in the form of tobacco fumes. For some months past,” added Mr. Seymour,
“he has been a constant resident at the Bag of Nails, where, as I am
led to believe, he pays for nothing but his tobacco; the worthy hostess
having found him a very profitable bait for customers, is too willing
to barter the drippings of the kitchen for his wit, and the leakage of
the tap-room for his songs.”
“I am very curious to become acquainted with this comical being,” said
the major.
“Suppose we walk into the village,” said Mr. Seymour; “we shall be
certain of finding him smoking his pipe on a bench before the alehouse
door; where he is as regularly stationed by his patroness, to catch
customers, as the saucer of treacle is placed in the window of a
pastry-cook to attract flies.”
“You will excuse my accompanying you,” cried Mr. Twaddleton; “I cannot
relish his stale jokes and potted stories.”
The gentlemen accordingly directed their route through Forest Lane, and
took leave of the vicar at the entrance of the church-yard. On arriving
within twenty yards of the public-house, Mr. Seymour noticed a column
of smoke which curled in wreaths about its porch. “There sits Ned,”
cried he; “I knew we should find him at his post.”
“Hopkins! Hopkins!” cried Mr. Seymour, “I fear you have not taken the
worthy vicar’s advice.”
“An old dog cannot alter its way of barking, sir; nor is it easy to
straight in the oak the crook that grew in the sapling.”
“I am to presume, then, to speak courteously, that you are still, ‘a
man of leisure.’”
“Ay, verily am I; as idle, sir, as a chimney in the dog-days,” replied
the wag of the tap-room.
“That, by the by, is not a very happy simile of yours, when applied to
a man who is _smoking_ all day long,” observed Mr. Seymour.
“I admit it,” said Ned, “so here’s another for you,--as lazy as
Ludlam’s dog, that leaned his head against the wall to bark. But, after
all, Mr. Seymour, a day of leisure is to me a golden age, and I am of
my Lord Peterborough’s way of thinking, who used to say, ‘a golden age
was that in which every one might _pipe_ when and where he pleased.’”
The wag, at this instant, gave such a practical illustration of his
theme, as would have suffocated the major, had not his military habits
rendered him smoke proof.
“In short, gentlemen,” continued Ned, “a pipe is the solace of my life
and the mainspring of my spirits; knock out my pipe and you knock out
my brains. I verily believe that, if I could not obtain the ‘furies’
frankincense,’ as they have been pleased to call tobacco, I should be
like Vicar Breedon, who, according to William Lilly, cut the bell-ropes
and smoked them.” So saying, he gave another puff, and then removing
the pipe from his mouth, sang the following ditty:--
“Little tube of magic power,
Charmer of an idle hour,
Object of my warm desire,
Lip of wax, and eye of fire;
And thy snowy taper waist,
With my finger gently braced.”
&c. &c.
“Always merry, Ned,” cried Mr. Seymour.
“Lord bless you, sir, what is life but a jest? I jest to live, and I
live but to jest. And so I shall continue to do, until I am put to bed
by the shovel.”
“Your father was a reputed jester, was he not?” asked Mr. Seymour.
“He was, God bless his memory! and it was his constant prayer that his
son Neddy might turn out as sharp a man as his father; and if there be
any truth in the adage that ‘dogs bark as they are bred,’ I certainly
had as good a chance of success as most people. Momus rocked my cradle;
I ate fire before I was seven years old; and so anxiously did my father
superintend my education, that he never suffered me to cut a morsel,
until I had cut a joke. ‘Neddy,’ he used to say, ‘I perceive you are
like my bagpipes, never audible except your pouch is full of wind; for
after a good meal you are as mum as a mouse in a mill; so remember, my
lad, no joke no pudding.’ Thus schooled, I became, through necessity, a
wit, and earned every mouthful by a pun; in short, after a little time,
my genius illumined every dish, and, like the fire of London, blazed
from Pudding Lane to Pie Corner.”
“And you afterwards appeared on the stage, as a candidate for popular
applause, which you were fortunate enough to obtain; how came you to
desert your calling?” said the major.
“He who licks honey from thorns pays too dearly for it,” replied the
wit. “So I packed my wardrobe in a pocket handkerchief, and trudged off
to Cockneyshire.”
“And what was your object?” asked the major.
“To carry my wit to a better market; and instead of retailing it at
country fairs, to offer it wholesale to some of the great publishers,
from whom I immediately received considerable orders. The profit which
rewarded my poetry soon convinced me, notwithstanding all that had been
said to the contrary, that there were still some gold mines in
Parnassus. I lived for the first week on liquid blacking. I well
remember it was winter, and although I contrived by my eulogies of the
jet polish, to obtain a daily meal from a neighbouring chop-house, I
was compelled to sit in my chamber at night without fire or candle,
until the publication of my song, ‘_Ah let my muse a flame inspire_,’
lighted a cheerful blaze in my grate, and enabled me to purchase a few
pounds of rush-lights. In short, gentlemen, without exhausting your
patience with a long recital of my adventures, suffice it to say, that
I have always been able to keep my pipe smoking by my _puffs_, my pot
boiling by the ebullition of my wit, and my grate blazing by the _fire_
of my genius; while paste and scissors have never failed to secure a
constant supply of _cabbage_, upon which I have thrived like any
caterpillar.”
Here Hopkins returned to the porch, and took a draught as deep as ever
Bitias drank, or the Athenian Diotimus, nicknamed the _Funnel_, ever
swallowed.
“Did I not say,” resumed the wag, “that my pipe was the nurse of wit? I
ought to have called her the _dry_ nurse. It is a hard case, gentlemen,
but I am in the situation of the flying-fish, incapable of keeping
myself up, unless I occasionally moisten my wings.”
“If you persist in this dreadful habit,” said Mr. Seymour, “you will
assuredly destroy the coat of your stomach!”
“The _coat_ of my stomach!” replied Ned; “if that is all, my stomach
must even be contented to do what its master has so often done before
it--go in its _waistcoat_, with the understanding that it shall have an
additional glass to keep it warm. The stomach had better give up its
_coat_ than its master his _habit_.”
“But suppose I could prove, that by giving up this system, you would
lengthen your days,” observed Mr. Seymour.
“Lengthen my days.--you are quite right, Mr. Seymour; being rather low
in cash, I was compelled to forego my comfort for one whole day, and it
was the longest day I ever knew in my life; you are quite correct, sir.”
“You are incorrigible, Ned. But come, what say you to a profitable
engagement?” asked Mr. Seymour.
“Why, as to that, sir, I have always a ready mouth for a ripe cherry.”
“You must know, then, that my friend, Major Snapwell, proposes to give
a grand rural fête to the inhabitants of Overton; and, as he intends to
convert his grounds into a fair upon the occasion, he is desirous of
finding some person acquainted with comic entertainments, who would
undertake the office of manager, to contract with the necessary
performers, and superintend all the arrangements.”
“I am the lad for the major’s silver,” said the delighted wag; “for
without vanity, I may say that few persons better understand the art of
mixing up the motley ingredients of fun and frolic; there is, besides,
that in the major’s face which I would willingly call master.”
“And were I to judge from your frontispiece,” said the major, “I should
say that every day in your calendar was a red-lettered one--the
painting of that red nose of yours must have cost a trifle.”
“Cannot tell; it is not yet finished,” retorted the wit.
Major Snapwell, with the assistance of Mr. Seymour, now entered more
fully into the nature and extent of the exhibitions which he wished
Hopkins to provide; but as he was, at present, unable to fix the exact
period for the fête, he directed him to take such steps only as might
be necessary for securing the performers, and to hold himself in
readiness for active service.
-----
Footnote 61:
Drake’s Shakspeare and his Times.
Footnote 62:
Ovid. Fast. 2. v. 525.
------------------------------------------------------------------------
[Illustration: Man using a Thaumatrope with a boy and girl looking on.]
------------------------------------------------------------------------
CHAPTER XVIII.
_The Thaumatrope.--A great improvement effected in its
construction.--Another toy upon the same optical principle._
Tom’s holidays were now drawing to a close, and the children were
summoned into the library to receive their last lesson in philosophy.
“You have lately witnessed an experiment,” said Mr. Seymour, “which
must have convinced you how liable the ear is to be deluded with
respect to the nature and direction of sound; I shall now show you that
the eye has also its sources of fallacy.”
“If you proceed in this manner, you will make us all Cartesians,”[63]
exclaimed the vicar.
“I shall illustrate my subject by means of a new toy which I have
lately invented,” said Mr. Seymour, “and unless I am much mistaken, it
will afford as much amusement to the elder as to the younger members of
our party, although the vicar may perhaps regard it as a more hostile
instrument than even that of the wooden horse which filled unhappy Troy
with an armed enemy. It is a small machine,” continued Mr. Seymour,
“which is well calculated to furnish us with some capital puns.”
“With puns!” exclaimed the horrified vicar, who no sooner heard this
appalling declaration, than like another Laocoon, he deprecated the
introduction of the “_donum exitiale_” within the walls of Overton
Lodge. But his hostility was soon disarmed, not by the circumvolutions
of a snake around the body of the enraged orator, but by the embraces
of little Rosa, who threw her arms around the neck of the vicar, with
such supplicating grace, that at length he exclaimed, “Well, well; if
it be the decree of the Fates, I must submit.”
During this altercation, Mr. Seymour had procured the “wooden engine”
from his study.
“I will first,” said he, “exhibit the toy in its original state, and
then show you the improvements which have been effected in it.”
“Let us hear the account of its operation,” said the major, “which I
perceive is enclosed within the box.”
“True,” replied Mr. Seymour; “and I think you will agree that I have
given a very plausible explanation of its effects.”
“Plausible,” muttered the vicar, “plausible enough, no doubt; oh the
Sinon!”
Mr. Seymour then proceeded. “This toy is termed the THAUMATROPE.”
“Of Grecian origin!” observed the vicar. “‘_Timeo Danaos et dona
ferentes_,’ as Virgil has it.”
“What is the meaning of the term?” asked Louisa. The vicar explained to
her that it was compounded of the Greek words, θαυηα, and τρεπω; the
former of which signified _wonder_, the latter _to turn_.
“Exactly,” replied Mr. Seymour. “‘_A Wonder-turner_,’ or a toy which
performs wonders by turning round: but let me proceed in the
explanation.” He then continued to read as follows: “This philosophical
toy is founded upon the well-known optical principle, that an
impression made on the retina of the eye lasts for a short interval
after the object which produced it has been withdrawn. During the rapid
whirling of the card, the figures on each of its sides are presented
with such quick transition, that they both appear at the same instant,
and thus occasion a very striking and magical effect. On each of these
cards a device is introduced, with an appropriate motto, or epigram;
the point of which is answered, or explained, by the change which the
figure assumes during the rapid whirling of the card.”
“It may be very clever,” said the vicar, “but I do not understand it.”
“But you shortly will; look at one of the cards.”
Mr. Seymour then displayed a pasteboard circle, on the one side of
which was figured a rat, and on the other, a cage; two strings were
fastened in its axis, by which the card could easily be made to
revolve, by means of the thumb and finger. Fearing that some of our
readers may be as dull of comprehension as the vicar, we have
introduced a sketch of the apparatus, in which both sides of the card
are exhibited, with the strings by which it is whirled round.
[Illustration: Two circular cards with strings attached, one with an
empty cage and one with a rat.]
No sooner had Mr. Seymour put the card in motion, than the vicar, in a
tone of the greatest surprise, exclaimed, “Magic! magic! I declare the
rat is in the cage!!”
“And what is the motto?” asked Louisa.
“Why is this rat like an opposition member in the House of Commons, who
joins the ministry?” replied Mr. Seymour.
“Ha, ha, ha!--excellent!” cried the major, as he read the following
answer: “because by _turning round_ he gains a snug berth, but ceases
to be free.”
“The very reverse to what occurred in ancient Rome, where the slave
became free by turning round,” observed the vicar.
The vicar, no doubt, alluded to the custom of making a freeman, as
described by Persius; from which it appears, that the clapping a cap on
the head, and giving him a turn on the heel, were necessary
circumstances. A slave thus qualified became a citizen of Rome, and was
honoured with a name more than belonged to any of his forefathers,
which Persius has repeated with a great deal of humour in his 5th
satire:--
“----Heu steriles veri, quibus una Quiritem
Vertigo facit!”
“That false enfranchisement with ease is found;
Slaves are made citizens by turning round.”
DRYDEN.
“Show us another card,” said Tom, eagerly.
“Here then is a watch-box; when I turn it round, you will see the
watchman comfortably sleeping at his post.”
“Very good! It is very surprising,” said the vicar.
“Yes,” observed the major; “and to carry on your political joke, it may
be said that, like most worthies who gain a post, by _turning round_,
he sleeps over his duty.”
“The epigram which accompanies it is not deficient in point,” said Mr.
Seymour.
“The caprice of this watchman surpasses all bound
He ne’er sits in his box, but when going his _round_
While he no sooner rests, ’tis a strange paradox!
Than he flies from his post, and _turns_ out of his box.”
“What have you there?” exclaimed the vicar; “arms and legs, without a
body?”
“Yes,” replied Mr. Seymour; “and which, on turning round, will present
the figure of a king, invested with all the insignia of royalty.”
“It is indeed a king. Look at his crown and sceptre!” cried Louisa.
“Now for the epigram,” said the major, who then read the following
lines:--
“Head, legs, and arms, alone appear;
Observe that _nobody_ is here;
Napoleon-like I undertake
Of nobody a king to make.”
The next card presented a laughing face, which on being turned round,
was instantly changed into a weeping one. The motto--_The sweetest
things turn sour_.
“The device is capital!” exclaimed the vicar, “I question whether Peter
of Cortona ever produced a more striking metamorphosis.”[64]
The other cards were now exhibited in succession, of which the box
contained eighteen, and the whole party, not even excepting the vicar,
were highly gratified with the amusement.
“But I have not yet read to you the author’s address to the public; and
which, I must say, contains a succession of very happy puns.”
“Spare me! spare me!” cried the vicar: “I like your toy, but cannot
discover the advantage of alloying amusement with such spurious wit,
and of associating science with buffoonery.”
Mr. Seymour, however, was relentless, and thus proceeded: “It is well
known that the Laputan philosopher invented a piece of machinery, by
which works could be composed by a mechanical operation; and the
Quarterly Review has asserted, that a certain English poem was
fabricated in Paris, by the powers of a steam-engine; but the author of
the present invention claims for himself the exclusive merit of having
first constructed a hand-mill, by which puns and epigrams may be
_turned_ with as much ease as tunes are played on the hand-organ, and
old jokes so _rounded_ and changed, as to assume all the airs of
originality. The inventor confidently anticipates the favour and
patronage of an enlightened and liberal public, on the well-grounded
assurance, that ‘_one good turn_ deserves another;’ and he trusts that
his discovery may afford the happy means of giving activity to wit that
has been long _stationary_; of _revolutionising_ the present system of
_standing_ jokes, and of putting into _rapid circulation_ the most
approved bon-mots.”
“Why, vicar, what ails thee?” exclaimed the major.
“Our subject has given him a _turn_; let him alone, and he will soon
_come round_,” observed Mr. Seymour.
The whole party, with the exception of Mr. Twaddleton, laughed
heartily; the vicar, however, did not relax a feature of his
countenance.
As soon as this ebullition had subsided, the major enquired of Mr.
Seymour, what was the nature of the improvement to which he had alluded.
“My proposed improvements refer both to the subjects exhibited on the
cards, and to the mechanism by which their changes are effected,”
replied Mr. Seymour.
“In the first place, it has occurred to me that this amusing toy might
be made instrumental in impressing classical subjects upon the memory
of young persons.”
This observation delighted the vicar, who said that he would patronise
such an attempt with all his heart.
“Why can we not,” continued he, “thus represent the Metamorphoses of
Ovid; or what say you, vicar, to converting the fleet of Æneas into
sea-nymphs, as Virgil has it?”
“An elegant thought! upon my word; a most elegant conception!”
exclaimed Mr. Twaddleton.
“What have we here?” interrupted the major, who had, for the first
time, noticed the superscription on the cover of the box: “had I seen
this before, I should have augured favourably of the toy: it is like
the sign of an inn, which is held out to announce good entertainment
within.” He then read the following:--
The Thaumatrope;
being
_Rounds_ of Amusement,
or
How to please and surprise
By _Turns_.
Mr. Seymour now proceeded to explain more fully the optical theory of
the instrument, which neither Louisa nor Tom could, as yet, thoroughly
understand.
He told them that an object was seen by the eye, in consequence of its
image being delineated on the retina, or optic nerve, which is situated
on the back part of the eye; and that it had been ascertained, by
experiment, that the impression which the mind thus receives, lasts for
about the eighth part of a second after the image is removed. “It is,
therefore, sufficiently evident,” said Mr. Seymour, “that if any point,
as a lighted stick, be made to revolve, so as to complete the circle in
that period, we shall not see a fiery point, but a fiery circle;
because the impression made by it in every point of its circuit will
remain until it comes round again to the spot from which it set
out;--but we will, at once, exemplify this fact by an experiment.”
Tom was accordingly directed to procure a piece of stick and a candle;
and as soon as they were brought into the room, Mr. Seymour ignited the
end of the stick and whirled it round, when a bright circle, without
any intervals of darkness, was seen by the whole party.
“Never until this instant,” exclaimed the vicar, with an expression of
high satisfaction, “did I fully appreciate the beauty of that passage
in Milton, wherein the poet evidently describes the rapidity of Satan’s
flight, as well as the refulgence of his appearance--
“‘Sprung upward like a pyramid of fire.’
“Now to take in the full meaning of this figure,” continued Mr.
Twaddleton, “we must imagine ourselves in chaos, and that a vast
luminous body is rising near the spot where we may be supposed to be
standing, so swiftly as to appear a continued track of light, and
lessening to the view, according to the increase of distance, until it
ends in a point, and then disappears; and all this must be supposed to
strike our eye at one instant.”
“It is very probable,” said Mr. Seymour, “that the poet had such an
idea in view, and that he intended by it to convey the immense rapidity
of Satan’s flight. Homer makes use of the same figure to express the
velocity of the javelin, δολιχοσκιον εγχος, the ‘_long shadowed_’
javelin. We shall have ample proof of the effect of this power in the
eye of retaining impressions, and of thus converting points into lines
and circles, during the exhibition of your fire-works; and which, in
fact, derive the greater part of their magical effect from it.”
“The pin wheel is certainly nothing more than a fiery circle produced
by the rapid revolution of a jet of flame,” said the vicar.
“And the rocket,” added Mr. Seymour, “is a column of light occasioned
by the same rapid movement of a burning body in a rectilinear or curved
direction.”
“I perfectly understand all that you have said,” observed Tom.
“Then you will not have any difficulty in explaining the action of the
Thaumatrope, for it depends upon the same optical principle; the
impression made on the retina by the image, which is delineated on one
side of the card, is not erased before that which is painted on the
opposite side is presented to the eye; and the consequence is, that you
see both sides at once.”
“Or, you might put it in this way,” said the major: “that as the image
remains the eighth of a second on the retina, after it has been
withdrawn from the eye, a revolution of eight times in a second will
secure its uninterrupted continuance.”
“On turning round the card,” observed Louisa, “I perceive that every
part of the figure is not equally distinct.”
“Because every part of the card does not revolve with the same
velocity,” said her father; “and this fact offers a good illustration
of what I formerly stated,[65] that in circular motion, the parts more
remote from the axis of rotation are those which move with the greater
velocity. This toy will also be found capable of exemplifying another
truth to which I have before alluded, that ‘the axis of motion remains
at rest while all the parts revolve round it.’”[66]
“I remember that very well,” exclaimed Tom.
“Then take the card, and spin it between yourself and the window, and
tell me what you observe,” said his father.
“I see a dark line across the window; and what is very strange, the
other parts of the card appear transparent; for they do not obstruct
the view of the window, as they would if the card were at rest.”
“The dark line you see is the axis of rotation, which being stationary,
necessarily excludes the light; the other parts being in motion do not
remain a sufficient time to obliterate the image made on the eye by the
window. It is true that the card disc passes between your eye and the
light, but as it does not continue at any one point for more than the
eighth of a second, there is no more apparent intermission of the light
than what occurs during the winking of the eyes.”
“You allude to a very curious fact,” observed the vicar, “that,
although we are perpetually covering the eyeballs with our eyelids, we
are not conscious of the intervals of darkness.”
“The reason of which must surely be obvious from the explanation I have
just offered,” said Mr. Seymour: “the sensation of light is not
exchanged for that of darkness in so short a period as the twinkling of
the eye.”
“I admit the plausibility of your theory,” said the vicar; “but it
appears to me that objects frequently linger on the sight for a longer
period than that which you assign to them. I well remember seeing the
flame of a candle for several seconds after it had been suddenly
withdrawn from the apartment.”
“I admit that strong lights frequently continue for some time thus
visible in the ‘mind’s eye;’ and it is well known that such impressions
are often followed by images of similar shape, but of various colours.
In passing from sunshine to a dark room, we frequently witness the
appearance of stars and circles of vari-coloured light; but this
phenomenon is very distinct from that of the Thaumatrope, and is to be
explained upon very different principles.”[67]
“I know exactly to what you allude,” said the major: “and I do not
doubt but that many of those illusive appearances, which have been
described, might be referred to the operation of the same natural
cause. It is easy to imagine that a person who has steadfastly fixed
his eyes upon an illuminated object, may, for some minutes afterwards,
see the same figure in shade; it was from such a cause, no doubt, that
Constantine saw the image of a cross in the sky. You are, probably,
acquainted with the opinions of Eusebius, Fabricius, and Dr. Lardner,
upon this alleged miracle.”
“Yes,” exclaimed the vicar, “and I also know, that this miracle for the
conversion of Constantine gave origin to the Catholic custom of
illuminating the cross at St. Peter’s in Rome.”
“Sir David Brewster, in his late work on Natural Magic, has given us a
beautiful illustration of the same principle; it is as follows,” said
Mr. Seymour. “A figure dressed in _black_ and mounted upon a _white_
horse, was riding along exposed to the bright rays of the sun, which
through a small opening in the clouds was throwing its light only upon
that part of the landscape. The _black_ figure was projected against a
white cloud, and the white horse shone with particular brilliancy by
its contrast with the dark soil against which it was seen. A person
interested in the arrival of such a stranger, had been for some time
following his movements with intense anxiety; but upon his
disappearance behind a wood, was surprised to observe the spectre of
the mounted stranger in the form of a _white_ rider upon a _black_
steed, and this spectre was seen for some time in the sky, or upon any
pale ground to which the eye was directed.”
“I cannot understand why the spectre should be opposite in colour to
the real image,” observed Tom.
“It is a law of vision which you must for the present take for
granted,” answered his father; “that such is the fact, however,”
continued he, “I will satisfy you by a very simple experiment.”
Mr. Seymour here placed three different coloured wafers in a triangular
form on a piece of white paper, and instructed his son to fix his eyes
steadily upon them for a minute; this having been performed, he next
directed him to turn them from the wafers to a blank part of the paper,
and to tell him what he saw.
“I see,” exclaimed Tom, “three spectral wafers, but the colours are
different; the red wafer is represented by a _green_, the violet by a
_yellow_, and the orange by a _blue_.”
“You now then understand what is meant by the spectral or accidental
colour of a body:--But let us return to the subject of the
Thaumatrope,” said Mr. Seymour.
“Behold!” continued he, “the Trojan ships!”
“Ay, ay, sure enough,” said the vicar; “but let me see, are their forms
according to ancient authority? Very well indeed, Mr. Seymour. Very
well; the poops have the bend so accurately described by Ovid and
Virgil--‘_puppesque recurvæ_,’ as the poet has it. And there is the
triton; but is its size in proportion to the vessel? Yes, sir, you are
doubtless correct, the figure is generally represented of considerable
magnitude on ancient medals; and Silius Italicus, if my memory serves
me, alludes to the weight of the image having on some occasions
contributed to the wreck of the vessel.”
“Spin them round,” said Mr. Seymour.
The vicar complied; exclaiming at the same moment, “‘_Vos ite solutæ.
Ite deæ pelagi._’ They are positively converted into sea-nymphs.
‘_Mirabile monstrum!_’” cried Mr. Twaddleton.
“Here is another classical device; the representation of Eurydice, as
she fell lifeless at the moment Orpheus turned round to gaze on her,”
said Mr. Seymour.
“Charming! charming! I perceive that it is a copy from the splendid
print of Didot in the Paris edition of Virgil.”
“Turn it round, vicar.”
“See! see! she revives, she opens her eyes, and throws her arms around
the neck of her frantic lover: truly, Mr. Seymour, this is a most
interesting toy,” said Mr. Twaddleton.
Mr. Seymour here observed that he had written an epigram to accompany
the subject they had just witnessed, and he trusted that he had given
to it a classical _turn_.
“By all means read it; the subject admits of much classical
decoration,” observed the vicar.
Louisa received the epigram from the hands of her father, and read as
follows:--
“By _turning round_, ’tis said, that Orpheus lost his wife;
Let him _turn round_ again, and she’ll _return_ to life.”
It could not be expected that Mr. Twaddleton should have admired lines
so burdened with puns; but he quietly observed, “I should have
preferred a quotation from the fourth Georgic, so beautifully
descriptive of the fable.”
The next card that was presented for inspection exhibited the
metamorphosis of Daphne into a laurel. As the figure revolved, the
leaves were seen sprouting from her fingers, and her arms lengthening
into branches.
“Come now,” said Mr. Seymour, “let us exhibit the figure which has been
designed at my request: the change which it will undergo during its
revolution may, I trust, on some day be realised; I only regret that it
is not in my power to give the vicar so good a _turn_.”
“Really, if like Crambe, in Martinus Scriblerus, thou hadst a word for
every day in the year, I should certainly say that you were this day
under the dominion of the word _turn_.”
“You know this resemblance?” said Mr. Seymour, as he showed the figure,
painted on one side of the card, to his daughter.
“It is the vicar!” exclaimed Louisa.
It was, indeed, a portrait of that most excellent character,
represented in the costume in which he usually appeared.
“Turn it round,” said Mrs. Seymour.
Louisa twirled the cord, and the effect of the rotation was to convert
the humble vicar into the dignified bishop; his meagre form was
instantly changed into a corpulent figure, which was still farther
inflated by the addition of the episcopal robe and lawn sleeves, while
his angular features were softened by the graceful curves of an immense
wig.
“I will give you a motto for it,” said the major, “and may it be
prophetic!--RAPID PREFERMENT.”
“I will now show you the improvement which has been effected in the
construction and use of this toy,” said Mr. Seymour. “It consists in
altering the axis of rotation while the card is in the act of
revolving, in order that the images on its opposite sides may be
brought in different positions with respect to each other.”
“There cannot be any doubt that such would be the effect, were it
possible to change the axis in the way you propose, but how is this to
be effected?” asked the vicar.
“At first I attempted to produce the change by the addition of several
other strings, but I soon found, that, in order to avail myself of this
expedient, I should be obliged to stop the card before I could alter
the axis, whereas my great object, as I have just stated, was to
produce the change while the card was in the act of spinning,” answered
Mr. Seymour.
“And I shrewdly suspect that such must necessarily be the case, adopt
whatever expedient you may,” observed the major.
“No indeed; I have at length succeeded to my entire satisfaction, and
that too by a most simple scheme, after having tried without success
many very complicated contrivances.”
The party were very desirous of witnessing this triumph of skill, and
Mr. Seymour produced the card, with its appendages, of which we shall
here present our readers with an engraving:--
[Illustration: Fig. 1. Circular card with bottle and another with man’s
torso.]
In all respects the card is constructed like the common Thaumatrope;
the subject, it will be perceived, is that of a man drinking, the
bottle being placed on one side, and the head on the other; upon
revolving the card, in the ordinary manner, the two images will appear
together as represented in:
[Illustration: Fig. 2. Man with bottle halfway to his mouth.]
The improvement consists in inserting in one, or, if a still greater
change be desired, in both sides of the card, two strings, as seen in
Fig. 1; viz. A D and A E, which united at A, form a common string for
twirling the card. The cord A D is elastic, while the string A E is
incapable of being stretched. If, therefore, while the card is in the
act of spinning, the cord A D be pulled with an increased force, it
will take the position D C, while the inelastic string A E will at the
same time assume that of E C. The consequence of which will be that,
instead of the card spinning on an axis in the direction A B, it will
now spin on that which is in the direction C B, and we shall
accordingly see the images on the opposite sides of the card in
different positions, with respect to each other; at one moment the
bottle will be seen in the hand of the drinker as represented in
Fig. 2, and in the next, at his mouth as shown in the cut below:
[Illustration: Fig. 3. Man with bottle at his mouth.]
while, by alternately tightening and relaxing the string, the figure
will be seen in the very act of raising and lowering the bottle.
Mr. Seymour having explained the principle of his improvement as we
have above related, proceeded to exemplify it by a series of different
subjects. We shall select two or three of them for the sake of
illustration. A card with a jockey on one side and a horse on the
other, on spinning round presented the combined figure; upon tightening
the string, in the manner we have described, the card changed its axis,
without the slightest halt or hesitation in its rotation, and the rider
was in an instant canted over the head of his charger; in a moment,
however, he appeared remounted; after which, by pulling the string,
with different degrees of force, he was made to stand on the saddle,
and to exhibit a number of different movements.
The figure of an Indian juggler was represented in the act of throwing
up _two_ balls; on spinning the card, and, at the same time, altering
the position of the circle, in the manner already described, _three_,
and afterwards _four_, became visible. When the card revolved upon its
original axis, two of the balls on the reverse side coincided with the
two painted on the front, so that during the revolution they fell upon
the same spot on the retina, and therefore produced a single
impression; but as soon as the position of the card was changed, these
spots were brought upon different points, and consequently produced
separate and independent images. By alternately tightening and relaxing
the strings, the balls were seen in motion, arising from and falling
into the hand of the juggler.
The next subject which we shall describe produced a considerable degree
of merriment. The vicar inspected the drawing, and observed that he saw
a pulpit placed on the banks of a pond; the card was made to spin, when
a tailor was seen haranguing from the former, and a goose, at the same
instant, fluttering over the water. The circle was now suddenly
shifted, and the vicar was desired to state what he saw:--“Why, bless
me!” exclaimed Mr. Twaddleton, “the tailor is justly served, he is
ducked in the pond, while the goose has taken his place in the pulpit.”
Fearing that we may have exhausted the patience of our reader, we shall
only relate one more example. It was a Turk, who, by means of the
expedient we are illustrating, was made to draw his sabre, and cut off
the head of his antagonist, which immediately fell into the hands of
the decapitated person, who, like St. Denys, appeared as if walking off
with perfect indifference.
“You must admit that these effects are no less novel than they are
extraordinary, and that they are capable of almost endless variation,”
said Mr. Seymour.
“I admit it all,” replied Mr. Twaddleton, “and I have only to express a
hope that, amidst all your improvements, you will never lose sight of
your first and most laudable design, that of rendering your toy
subservient to classical illustration: your triumph will then be
complete, and I shall willingly acknowledge that there is not only
philosophy but literature in your sport.”
“I must not quit this subject,” said Mr. Seymour, “until I have
exhibited another toy, which, like the Thaumatrope, is indebted for its
effect to the optical principle, which I trust is now well understood
by all present, viz. that _an impression made on the retina lasts for a
certain period after the object itself has been withdrawn_.”
The annexed wood-cut represents the instrument to which Mr. Seymour
alluded.
[Illustration: A blackened tin plate with slit, mounted on stand, in
view A; the image of a star as seen, in view B.] It consists of a disc
of blackened tin plate, which is made to revolve on its axis in the
manner above exhibited. A narrow opening extends from the circumference
to the centre as seen at A. If a device of any kind, as a star (which
for increasing the beauty of the experiment ought to be transparent,
and illuminated with a lamp) be placed behind the disc, it is evident
that, as long as the circle remains at rest, no other part of the
figure can be visible than that which is immediately behind the slit A,
but the instant it is put into rapid motion, the whole of the star will
be seen, as exhibited in figure B.
Mr. Seymour observed that the explanation of the phenomenon was
obvious;--each successive portion of the figure seen through the
opening remains on the eye, until the circle has completed its entire
revolution.
“This experiment,” continued Mr. Seymour, “admits of a very curious
modification, which I shall now proceed to exhibit.”
Three coloured wafers were then placed, at equal distances from each
other, on the disc, and the instrument having been arranged before a
looking-glass, the party were desired to observe the reflected image as
the circle revolved.
“The wafers are blended into one continuous zone,” observed Mrs.
Seymour.
“To be sure,” said Louisa; “upon the same principle that the ignited
stick appears as a fiery circle.”
“It would be very strange, after the different experiments we have
seen, if we were not able to explain the present appearance,” observed
Tom.
“The fiery circle produced by the revolving stick is a much better
illustration of the principle; I do not see what object Mr. Seymour has
in thus multiplying his experiments,” said the vicar.
“Gently, if you please, Mr. Twaddleton, and, before you favour us with
your criticism, wait until I have concluded my experiment. You have
seen that the reflected image of the revolving wafers appears as a
continuous zone, and you have very correctly explained the reason of
such an appearance; but I must now request you to inspect the reflected
image through the slit in the disc, as it revolves, and say what new
effect you observe.”
“How very strange!” exclaimed Tom; “I see the three wafers very
distinctly, and perfectly at rest.”
“Impossible,” exclaimed the vicar--“let me have a peep. Why, I declare,
they appear, as you say, stationary, although I know them to be in
rapid motion; as sure as fate I shall become a Cartesian.”
The Major, Louisa, and Mrs. Seymour, were all equally surprised, and
incapable of giving any explanation of the phenomenon they had
witnessed.
“Let us remember,” said Mr. Seymour, “that in viewing the image through
the slit in the revolving disc, we catch but a momentary glance as it
passes before the eye, and that the image thus produced on the retina
is retained until the next revolution again brings the slit into the
same position. Now it is evident, that before the eye can ascertain a
body to be in motion, it must observe it in two successive portions of
time, in order to compare its change of place;[68] but in the
experiment under consideration, the glance is momentary, the wafer is
no sooner seen than it passes away; its figure alone is impressed upon
the retina, and this impression is continued without any change, until
the circle completes its round, and consequently the image must appear
at rest.”
“I understand you; the figure, but not the motion, of the wafer, is
discernible in the short period during which it is visible through the
slit,” observed the vicar.
“I lately witnessed a beautiful illustration of this subject at the
Royal Institution,” said Mr. Seymour. “A number of cogged wheels, cut
out of pasteboard, were set in motion in a perfectly dark room, when
occasional flashes of light from an electric battery, displayed their
forms most distinctly, and yet although whirling round at the time,
they appeared to the spectator as motionless as so many solid blocks of
marble. In like manner, in a storm during the darkness of midnight, the
rolling ship and waves, when rendered visible by flashes of lightning,
will appear as completely at rest, as a representation of them upon the
canvass.[68a] I may at some future time extend this interesting
subject, by exhibiting some optical illusions produced by the
revolution of wheels in different directions, and at different
velocities, for the knowledge[69] of which we are indebted to Mr.
Faraday, and in mentioning that distinguished philosopher,” added Mr.
Seymour, addressing himself more particularly to the vicar, “I cannot
avoid remarking, that if _Philosophy in Sport_ can be made _Science in
Earnest_, the juvenile lectures delivered by that professor have
established the converse proposition, that the sternness of Science may
be relaxed into the engaging aspect of Sport.”
“Before quitting this subject,” continued he, “I have yet another toy
in store for your amusement; it is founded upon the optical principle
which I have every reason to believe you now thoroughly understand.” A
square box was then produced containing a number of card discs, the
edges of which exhibited a series of notches corresponding with the
figures delineated on their margins. That the reader may better
understand their construction, as well as the explanation of Mr.
Seymour, the following representation has been introduced.
[Illustration: As explained above. Figure is a dark-skinned man jumping
in the air.]
“To exhibit the magical effects of this toy,” said Mr. Seymour, “I
will, by means of the spindle to which it is attached, cause it to
revolve rapidly before the looking-glass, and you shall view the
reflection through the openings.”
Each member of the party obeyed in succession the direction thus given,
and severally expressed the great astonishment they felt, at observing
the figures in constant motion, and exhibiting the most grotesque
attitudes.
“Now,” said Mr. Seymour, “attend to my explanation. Each figure is seen
through the aperture, and as it passes and is succeeded in rapid
succession by another and another, differing from the former only in
attitude, the eye is cheated into the belief of its being the same
object successively changing the position of its body. Consider what
takes place in an image on the retina when we actually witness a man in
motion; for instance, a man jumping over a gate, in the first moment he
appears on the ground, in the next his legs are a few inches above it,
in the third they are nearly on a level with the rail, in the fourth he
is above it, and then in the successive moments he is seen descending
as he had previously risen. A precisely similar effect is produced on
the retina, by the successive substitution of figures in corresponding
attitudes, as seen through the orifices of the revolving disc; each
figure remaining on the retina long enough to allow its successor to
take its place without an interval that would destroy the illusion.”
“Nothing can be more satisfactory than your explanation of this very
extraordinary toy,” observed the vicar.
“I am now about to exhibit what I consider a great improvement in its
construction, inasmuch as we thus get rid of the mirror, and enable two
persons to witness the deception at the same time,” said Mr. Seymour.
“For this purpose I have a spindle, at each end of which a disc is
placed, and which I hold in my hand.” We deem it expedient to
illustrate this arrangement by a wood-cut.
[Illustration: Two-sided phantasmascope.]
“By revolving the spindle, you perceive that both cards are made to
turn round with equal velocity. Tom,” said his father, “look through
the orifices of the disc, on my right hand, and Louisa, do the same on
my left.” The children obeyed, and simultaneously expressed their
wonder at what they witnessed. “The figures are all dancing!” cried
Tom; “The horses are all prancing!” exclaimed Louisa.
“You have not yet told us the name of this toy,” observed the vicar.
“It has received several names,” answered Mr. Seymour, “as
_Phantasmascope_, _Phenakistiscope_, &c. derived, as you no doubt
perceive, from the Greek.”
It is scarcely necessary to observe, that the appearances thus produced
may be infinitely varied--heads opening their mouths, and distorting
their countenances; creeping serpents, and machinery in active
operation, are amongst the subjects that have excited the greatest
admiration.
The party now dispersed, not less gratified than they had been
instructed by the lesson of the morning.
* * * * *
The mighty magician of the North has compared the course of a narrative
to the progress of a stone rolled down hill by an idle truant boy,
“which at first moveth slowly, avoiding by inflection every obstacle of
the least importance; but when it has attained its full impulse, and
draws near the conclusion of its career, it smokes and thunders down,
making a rood at every spring, clearing hedge and ditch like a
Yorkshire huntsman, and becoming most furiously rapid in its course
when it is nearest to being consigned to rest for ever: even such,”
says he, “is the course of a narrative; the earlier events are
studiously dwelt upon; but when the story draws near its close, we
hurry over the circumstances, however important, which your imagination
must have forestalled, and leave you to suppose those things which it
would be abusing your patience to relate at length.”
Let the reader of the present work accept this explanation, as an
apology for the abrupt and rapid manner in which we shall now
accelerate our narrative. Since the last lecture, our history has
advanced nearly three weeks, during which interval the major had made
every arrangement for the approaching marriage. It was finally agreed
that the ceremony should be performed at Overton church; and as the
“happy couple” expressed a wish to pass their “honey moon” in a retired
part of Yorkshire, the major consented to postpone his fête until after
their return; nor was he displeased at such an arrangement, as it
afforded time for getting up his entertainment on a more liberal scale
than could otherwise have been accomplished. We shall now avail
ourselves of that peculiar Lethean property which has been often
ascribed to the pen of the author, and commit the reader to the arms of
Morpheus, where it is our intention that he shall remain until the
morning of the nuptials.
* * * * *
* * * * *
Reader, awake! the sun has risen, and Nature is robing herself in her
most gorgeous apparel for the approaching ceremony; the family of the
lodge have been already roused from their slumbers by the attendance of
minstrels, whom the vicar had directed to salute the bridal party at
break of day.----But hark! while we are thus trifling, the village of
Overton is in a bustle; the marriage ceremony is over; the bells of the
church are ringing right merrily their festive peals; many a
handkerchief is waving from the cottage windows, while the doors are
decorated with garlands; the vicarage is ornamented with fragments of
Venetian tapestry; the peasants, dressed in their holiday garments, are
carrying nosegays in their hands, to present to the bride as an
offering of their respect, or to strew in her path, as an emblematic
expression of their wishes.
The party having reached Osterley Park, we were proceeding to
describe the banquet which had been prepared, and the various devices
and emblems with which it had been decorated, under the classical
direction of the vicar, when alas! our publishers, like the harpies
of old, unexpectedly pounced upon us, and warned us from the
feast--“_diripiuntque dapes_,” as Virgil has it.
“You have already exceeded the prescribed limits--you must close the
scene--remember that you have engaged to condense the work into one
volume,” said they. We remonstrate, but in vain. We request but a few
pages, in order that we may give our characters a dramatic exit; but
they reply to us in the words of Sneer, in the Critic, “O never mind!
so as you get them off the stage, I’ll answer for it the _reader_ won’t
care how.”
You see then, gentle reader, how vain it would be to struggle against
such arbitrary and tasteless masters; we shall, therefore, without any
farther apology, ring the manager’s bell, and drop the curtain.
-----
Footnote 63:
The Cartesians maintained that the senses were the great sources of
deception; that everything with which they present us ought to be
suspected as false, or at least dubious, until our reason has
confirmed the report.
Footnote 64:
Ferdinand, Duke of Tuscany, was once struck with the picture of a
child crying; the artist (Peter of Cortona), who was at work upon the
head, wishing to give a proof of his skill, by a few judicious
touches converted the crying into a laughing face. The Duke was in
astonishment; the painter, to show himself master of the human
countenance, restored his first touches, and the Duke again saw the
child weeping.
Footnote 65:
Page 161.
Footnote 66:
Page 49.
Footnote 67:
Those who are desirous of gaining farther information upon this
subject may consult the chapter on “Ocular Spectra, or Accidental
colours,” in Brewster’s Natural Magic, p. 21; and Edinburgh
Encyclopædia, Art. Accidental Colours.
Footnote 68:
“Our knowledge of motion is a deduction of reasoning, not a
perception of sense; it is derived from the comparison of two
positions; the idea of a change of place is the result of that
comparison attained by a short process of reasoning.”--_Lord
Brougham._
Footnote 69:
See Journal of the Royal Institution, No. 2.
------------------------------------------------------------------------
CHAPTER XIX.
_Preparations for the approaching fête.--The procession of the
bridal party to Osterley Park.--The Major and his visitors
superintend the arrangements in the meadow.--The curious
discussions which took place on that occasion.--The origin of
the Swing.--Merry Andrews.--Trajetours, &c.--The dinner at the
Hall.--The learned controversy which was maintained with respect
to the game of Chess._
A month had nearly elapsed since the bridal pair had quitted Overton;
and during this period, the greatest activity had been displayed by the
itinerant corps of Momus, under the superintendence of their manager,
Ned Hopkins. The various show-booths had been erected by their
respective owners with an expedition that might have put many a prouder
architect to shame; the marquees and the temporary rooms had been
completed under the management of Tom Plank; and for those, whose
appetite might hold precedence of the senses of sight and hearing,
ample funds of gratification had been provided by the accomplished
hostess of the “Bag of Nails,” whose grim troop of kettles and
stew-pans had, during the whole of the week, been chirping and
chuckling over the kitchen range, the very cheeks of which had cracked
from yawning. The major now anxiously awaited the arrival of every
post, in expectation of a letter that might announce the day upon which
Henry Beacham and his bride would return to Osterley Park. At length
the long anticipated intelligence was received, that they might be
expected at Overton by four o’clock on the day after the morrow. The
vicar was immediately summoned to a council, and on his arrival,
retired with the major for the purpose of consulting the chronicles of
Holinshed and Froissart, touching certain points of ceremonial that
might guide them in their arrangements for receiving the bride. The
vicar pleaded in favour of the forms that were observed on the occasion
of the public entrance of Queen Isabella into the city of Paris, but
the major objected to the plan, on account of the pageant representing
the siege of Troy; a point upon which the vicar, as may be readily
imagined, most pertinaciously insisted; so that the gentlemen separated
without having arrived at any satisfactory conclusion upon the subject,
and the question was transferred to another jurisdiction. No sooner had
it become known that Mr. and Mrs. Beacham were shortly to arrive, than
the more respectable yeomen of the parish assembled at the village inn,
to concert a plan for receiving them with all due honour, when it was
finally arranged, that the village should be decorated with garlands,
and the May-pole erected on the spot, where its gaudy streamers had for
so many ages annually floated on the breeze of spring. It was farther
resolved, that every person who could furnish himself with a horse,
should attend at a certain spot by the hour of three, in order to
advance in procession, and escort the happy couple through Overton to
Osterley Park. The major, upon receiving these resolutions, issued such
orders as might be necessary for carrying them into effect; he also
signified his desire, that those musicians who had lately arrived for
the impending festivities should be in attendance at the place and hour
that had been fixed upon. The friends of Major Snapwell had already
arrived at the Park; and Overton Lodge was overflowing with visitors.
Tom had also joined his family circle.
At three o’clock on the appointed day, twenty signal guns were
discharged from the Park--the village bells struck up a festive
peal--the flag was hoisted on the spire of the church; and upwards of
forty respectable yeomen, farmers, and tenants, mounted on their horses
and decorated with ribands and flowers, had assembled as an escort.
The church clock chimed the quarter past three, as the carriages of
Major Snapwell and Mr. Seymour, and those of their guests, drawn by
highly decorated horses, entered the village; the peasants immediately
drew back, so as to form an avenue through which the party might pass,
while shouts of gladness rent the air. Each horseman had provided a
large bough of oak or elm, so that the cavalcade in motion appeared
like a moving grove, and reminded Mrs. Seymour of the advance of
“Birnam Wood to Dunsinane.” The carriages, preceded by a band of music,
occupied the van of the procession; then came about fifty village
maidens, each carrying in her hand a basket of flowers; next followed
the horsemen; and the procession was closed by a dense group of
peasants, who had come from all the country round. The vicar appeared
on horseback, bustling in all directions, now conversing with the
major, now with Mr. Seymour; at one time moderating the pace of the
horsemen, and at another, keeping back the pedestrians, whose eagerness
to push forward created an inconvenient crowd in the foremost ranks.
Mr. Twaddleton held in his right hand a wand decorated with ivy leaves,
and which resembled in appearance the thyrsus of Bacchus, except that
the cone on its summit had been replaced by a bunch of roses. This was
a classical conceit; and he fully explained to the major the reason of
his having adopted such a device for his wand of office.
“The rose,” said he, “was dedicated by Cupid to Harpocrates, the god of
silence, to engage him to conceal the secrets of Venus; hence has this
flower ever since been considered as the symbol of silence; for which
reason it was customary to hang a rose over the banqueting-table, to
signify that what was there spoken should be kept private, or ‘under
the rose;’ whence, also, to present, or hold up, this flower to any
person in discourse served, instead of an admonition, to intimate that
it was time for such person to hold his peace. In like manner,”
continued the antiquary, “you will observe that, by virtue of my wand,
I shall impress the obligation of silence upon the crowd, and easily
calm any undue clamour that may arise.”
The cavalcade had advanced little more than half a mile, when the major
suggested the propriety of halting, until his nephew and niece should
arrive; to this proposition the vicar readily acceded, and accordingly
issued the necessary orders.
They had not, however, remained stationary above five minutes, when a
carriage and four were seen at the brow of the hill, advancing in full
speed. A general and simultaneous shout burst from the crowd; upon
which the vicar raised his wand, and all was hushed. How far such an
effect might be attributed to the influence of his wand, we shall leave
the sagacious reader to determine; but the party smiled at so striking
an instance of classical credulity; and Mr. Twaddleton, highly
gratified by his triumph, rode forward to the chariot, which was not
more than two hundred yards distant. It contained Mr. and Mrs. Beacham,
whom the vicar no sooner perceived, than he again raised his wand, and
again witnessed the influence of its spell. The chariot instantly
stopped, and, in the next moment, Mr. Twaddleton was seen in earnest
conversation with the travellers. He informed them that the group they
saw was a cavalcade of villagers, who had been awaiting their arrival
on the road, in order to escort them in rural triumph to Osterley Park.
He then presented Mr. Beacham with a bag of nuts, “that the
bridegroom,” as he said, “might be enabled to comply with the ancient
Roman custom[70] of throwing nuts amongst the boys to be scrambled
for;--_sparge, marite, nuces_, as Virgil has it;--_da nuces pueris_, as
Catullus sings.” Mr. Beacham held the vicar in too much respect to
laugh at his eccentricities, and he therefore accepted the bag, with a
determination to gratify his wishes in so harmless a whim.
Jerry Styles was now directed to forward the two messengers to Osterley
Park; and he accordingly opened a basket, from which flew two carrier
pigeons, who immediately soared into the air, and having attained their
greatest altitude, and remained apparently stationary for a few
seconds, darted off in the direction of Osterley Park; every eye was
steadfastly fixed upon the bird [sic]; and a murmur of satisfaction and
wonder ran through the ranks, as the sagacious animals lessened in the
distance.(52)
The musicians struck up a grand march;--the whole cavalcade was in
motion. Mr. Beacham’s chariot having been drawn on one side of the
road, the carriages and horsemen proceeded to take their stations in
the rear; the company in the former kissing their hands, and waving
their handkerchiefs, while the latter lowered their branches, and
cheered, as they passed.
The damsels, in advance of Mr. Beacham’s carriage, opened their
baskets, and strewed the road with flowers as they moved forward.
“Hark!” exclaimed the major: “the pigeons have arrived at the park, and
my orders have been faithfully obeyed: they are firing a salute.”
“And it has been heard at the village,” said the vicar; “for the bells
have just commenced their peal of welcome.” But we are exhausting the
patience of our readers with the details of a ceremony, in which it is
very probable they may feel but little interest; although we freely
confess that, to ourselves, few pageants have such attractive charms as
those innocent and simple manifestations of genuine feeling which are
to be met with in rural life, where the heart has not yet been chilled
by that benumbing influence of what has been termed “the progress of
civilisation;” and which has exchanged the free and warm impulses of
our nature for cold and studied forms, or for an artful display of
factitious sentiment.
During the progress of the procession through the village, Mr. Beacham
had not been unmindful of the vicar’s request; he poured a shower of
nuts amongst the boys, which occasioned much frolic, and good-humoured
contention; while the peasants caught and cracked them, without any
suspicion of the Roman custom they were assisting to perpetuate.
Having arrived at Osterley Park, the horsemen formed a double line,
through which the several carriages passed. The gates were then closed;
and the vicar, stepping forward, thus addressed the assembled
multitude:--
“Well-beloved friends and parishioners, I am desired by Major Snapwell
to inform you that refreshments have been prepared in the village, of
which you may all partake on your return. Your admission into the park
this evening would interfere with those arrangements which are in
progress for to-morrow’s jubilee: let me, therefore, request that you
will all retire peaceably.”
In compliance with this intimation, the whole assembly,
“With tongues all loudness, and with eyes all mirth,”
after having given three hearty cheers, retired to the village, where
several barrels of beer had been disposed in readiness for the libation.
The vicar, having completed his harangue, rejoined the party at the
park, where its hospitable owner had prepared a sumptuous dinner. It
was, however, proposed that the vicar, with the major, and such of his
guests as wished to inspect the preparations, should previously walk
round the grounds. Tom and his sisters begged that they might be
included in the party; a request which their father readily granted, as
he said that some opportunity might occur for explaining the nature of
those exhibitions which they were to witness on the following day. The
same feeling induced Mr. and Mrs. Beacham and several other visitors to
join the party, hoping that they also might profit from the discourse
which Mr. Seymour intended to hold for the instruction of his children.
The reader will probably be induced, for similar reasons, to accompany
them. If he has attentively read the preceding pages of this work, we
hope he has become convinced that the lessons of youth may occasionally
convey instruction as well as amusement to those of riper years.
Ned Hopkins having been summoned to attend the party, and receive the
final orders of the vicar, they proceeded to the elm-meadow, where the
grand fair was to be held, and in which were disposed a long line of
booths for the motley exhibitions to which they were dedicated.
“What have we here?” exclaimed the major, as he entered the meadow; “a
row of poles!”
“Ned Hopkins,” cried the vicar, “how has it happened that the ropes
have not been affixed to these poles? Have I not said that every
arrangement must be completed this evening? Those poles,” continued the
vicar, addressing himself to Major Snapwell, “are intended for swings,
from which the younger peasants will, doubtless, derive much amusement,
while their sires are engaged, in the adjoining field, by the more
manly exercises of quoits, foot-racing, wrestling, hurling, &c. You
are, of course, aware, gentlemen, that in admitting the swing amongst
the pastimes of the day, I have the support of classical authority: its
origin may be traced to the Icarian games, the celebration of which
consisted in persons balancing themselves on cords attached to two
trees; or in other words, in swinging. They were instituted in
commemoration of the death of Erigone, who no sooner discovered the
murder of her father Icarus, than she piously hung herself at his tomb.”
“It is certainly very curious,” said the major, “to observe how
frequently a popular ceremony or custom has survived the tradition of
its origin; it is thus, for instance, that the fond mother still
suspends the coral toy around the neck of her infant, without being in
the least aware of the superstitious belief from which the custom
sprang (53); and I have little doubt but that we shall to-morrow hear
the chorus of ‘Derry-down’ re-echoed by those who probably never heard
of the Druids, and much less of the choral hymns with which their
groves resounded, at the time of gathering the misletoe.”
“You need not go so far back as the Druids,” said Mr. Seymour; “does
not the housewife place the poker across the grate to draw up the fire,
without ever suspecting that the custom originated from the
superstitious belief that, by thus forming a cross with the bars, the
fire was protected from the malignant influence of witches?--But let us
proceed; for what has yonder stage been erected?”
“That is the _hoistings_, sir,” exclaimed Ned Hopkins, “from which
Giles Gingerly, the celebrated American merry-andrew, will exhibit his
buffoonery, and vend his nostrums.”
“Hoistings! why, Ned, you pronounce the word as though your mouth were
filled with hot pudding,” said the major.
“I ask your pardon, sir,” replied Ned; “but my father would never
suffer me to pronounce it in any other manner; for he always maintained
that _hustings_ was a corruption for _hoistings_, it being a stage upon
which the actor is _hoisted_ or elevated above the surrounding crowd.”
“I believe he is right,” muttered the vicar.
“Papa,” said Tom, “pray tell me what is a merry-andrew.”
“Ask the vicar,” replied his father.
“The mountebank, who united the professions of joculator and physician,
was of ancient date, and during the two last centuries has figured away
with considerable success. He usually appears on a temporary stage, and
prefaces the vending of his nostrums with a pompous harangue; and, the
better to attract the notice of the gaping spectators, he displays some
of the performances practised by the jugglers, while his inseparable
companion, the _bourdour_, exhibits numerous tricks, and puts the
populace in good humour by wit and raillery. The medical fraternity,
known in England by the name of _Merry-andrews_, and who are the
companions of the mountebank, derived their foundation from Dr. Andrew
Boorde, who lived in the reigns of Henry VIII. Edward VI. and Queen
Mary, and was constantly in the habit of frequenting fairs and markets,
at which he harangued the populace: his speeches were extremely
humorous, and occasioned considerable mirth; but, notwithstanding the
infallibility of his nostrums, like Paracelsus, he died with a bottle
of his elixir in his pocket. His successors in the same line naturally
endeavoured to emulate the humour of their master, and hence this whole
class of vagabond tinkers of flesh and bone acquired the generic
appellation of ‘_Merry-andrews_’.”
“And pray what are _nostrums_?” asked Louisa.
“‘_Nostrum_,’ my dear, signifies _our own_, and is applied to any
medicine which is prepared by a secret process, and sold for the
private advantage of an individual; but, since secrecy is never used on
such occasions except as a cloak for imposture, the word very generally
conveys an expression of ridicule or contempt.”
The company proceeded in their inspection.
“What have we there, Ned Hopkins?” said Mr. Seymour, as he pointed to a
booth of larger dimensions than those which surrounded it.
“In that booth, ‘the Emperor of all the Conjurors’ will perform his
wonderful art of ‘sleight-of-hand,’” replied Ned.--“Look at his card of
invitation,” continued the wag--“☞ WALK IN--WALK IN--LADIES AND
GENTLEMEN. HERE ARE MIRACLES IN ANY QUANTITY TO BE SEEN FOR TWO-PENCE,
AND BELIEVED IN FOR NOTHING!!!”
“A lineal descendant of the _Tragetour_ of the fourteenth century,”
observed the vicar; “a class of artists who, with the assistance of
dexterity of execution, and various kinds of machinery, deceived the
eyes of the spectators, and produced such illusions as were usually
supposed to be the effect of enchantment; on which account they were
frequently ranked with magicians, sorcerers, and witches. They were
greatly encouraged in the middle ages, and travelled in large
companies, carrying with them such machinery as was necessary for the
performance of their deceptions.”
“And what may be the etymology of _tragetour_?” asked Mr. Seymour.
“A late ingenious writer supposes it to be derived from _trebuchet_, or
_trap-door_, of which he made frequent use during his performance.”
The company passed to the next booth.
“There,” said Ned, “will be exhibited vaulting, tumbling, jumping
through hoops, balancing, grotesque dances by the clown, and dancing
upon the tight-rope.”
“The tragetour rarely executed this part of the performance himself,”
said the vicar, “but left it to some of his confederates.”
“And yet I should have thought it the most profitable department of the
art,” observed the major; “for it was so patronised as to secure the
reception of its professors into the houses of the nobility. In the
reign of Edward II. a tumbler rode before the King, and so delighted
his Majesty, that he rewarded him with a gratuity of twenty shillings,
a very considerable sum in those days.”
The whole party, having expressed their satisfaction at the genius
which Ned Hopkins had displayed in selecting and arranging the various
kinds of amusement, were conducted by the vicar to a small enclosure at
a short distance from the fair, which he had appropriated to the youths
of the village, who had been trained to perform the “_Ludus Trojæ_,”
according to the description left us by Virgil in the fifth Æneid.
“I shall be curious to witness the sport,” said the major, “for Lazius
asserts, in his commentaries upon the Roman Republic, that the jousts
and tournaments, so much in fashion about two or three hundred years
ago, were indebted for their origin to this game; and that
‘_Tournamenta_’ is but a corruption of ‘_Trojamenta_.’”
“Undoubtedly,” replied the vicar; “and the learned and noble Du Fresne
entertains the same opinion: by some the word has been derived from the
French _tourner_, to turn round with agility; yet the exercises have so
much resemblance, as to prove the one an imitation of the other.”
“Come, come, my good friend,” exclaimed the honest major, “all these
preparations are highly laudable, and will, no doubt, afford
satisfaction to the spectators, for whose amusement they have been
designed; but there are other senses, besides the eye and ear, to be
gratified upon this occasion. I have not yet observed any arrangements
for the dinner.”
“Fear not, major; the awning which has been erected for that purpose is
within sight: observe you not the banners which are floating yonder?”
said the vicar.
“Ay, ay, to be sure I do; and let me tell you, that you have taken up a
very snug position.”
Tables had been arranged, under an awning of canvass, in the form of a
cross, and were capable of accommodating about two hundred persons. On
a platform, somewhat elevated, was another table appropriated to the
major and his guests, on which covers were laid for forty.
“You perceive, major,” said Mr. Twaddleton, as they approached the
scene of future action, “that the fare which has been provided is
simple but substantial, and I trust will be considered as no less
according with English hospitality, than with classical propriety.”
“The beef certainly predominates,” said the major; “and I observe that
most of the joints are roasted.”
“Quite correct, sir; the ox is the animal most frequently spoken of, as
furnishing food for ancient heroes; and you will remember that Homer
rarely mentions any other than _roasted_ meat.”
“I perceive that you have been more miscellaneous in your arrangement
of the upper table.”
“I have placed before you a chine of beef, because Menelaus set that
dish before Telemachus at the marriage-feast of his son.”
“And I rejoice to see a salad for its neighbour,” said the major.
“Ay, truly an _Attic_ salad, with garlic, leeks, and cheese: you no
doubt remember that the poetical salad served up in the comedy of the
Peace of Aristophanes was of this composition,” added the vicar.
“I wish to know what seats are to be appropriated to my young friends
the little Seymours?” said the major.
“I regret extremely to say, that they cannot with propriety join our
party,” replied the vicar, gravely.
“Not join the party! zounds, sir, but I insist upon it;--not join the
party!”--
“Be calm, major; and believe me that I shall feel the privation as
keenly as yourself; but would you countenance a measure, which is
decidedly in opposition to every classical authority? Never, as
Suetonius has expressly declared, did the young Cæsars, Caius and
Lucius, eat at the table of Augustus, until they had assumed the _toga
virilis_.”
“A fig for Suetonius; he is not to be trusted: has it not been said,
that, while he exposed the deformities of the Cæsars, he wrote with all
the licentiousness and extravagance with which they lived? Besides, can
we trust the opinion of a man, on a subject of etiquette, who was
banished from the court for want of attention and respect to the
Empress Sabina? You must produce some better authority, my dear Mr.
Twaddleton: search the Grecian writers; depend upon it that some direct
or implied sanction to the plan is to be discovered; the oracles of old
may generally be so interpreted as to meet the wishes of the
translator.”
“Gently, Major Snapwell; speak not so irreverently of the luminaries of
antiquity; nor expect me to distort passages from their original and
intended significations. An idea, however, has just struck me, which
may, possibly, be turned to your advantage; and yet there are many
difficulties; for it cannot be that this feast has been conducted with
the utmost frugality; and, therefore, must not be compared with the
Lacedemonian ‘_Syssitia_,’ or public entertainments, whither the youths
were obliged, by the lawgiver, to repair as to schools of temperance
and sobriety, and where, by the example and discourse of the elder men,
they were trained to good manners and useful knowledge.”
“A case exactly in point,” exclaimed the major. “Must not the classical
character of our entertainment convey instruction? I vow it runs
parallel in every particular with the Syssitia of Lacedemon; and I
therefore affirm, that it would be illegal, according to the law of
Lycurgus, to prevent the presence of the young Seymours.”
“Your argument has colour, major; I must admit that Mr. Seymour’s
lessons are too valuable to be lost: well, I consent; it shall be a
Lacedemonian entertainment, and my young friends shall be accordingly
accommodated with seats.”
On their return from the banqueting-tables, the party inspected the
preparations for the fire-works, and the ships constructed for the
naumachia; we shall, however, at present decline offering any
description, as we prefer explaining them in operation.
The reader will now be pleased to imagine that the party having
returned to the mansion, had partaken of the hospitable repast which
the major had provided for them; he may farther suppose that tea had
been served up, and the amusements of the evening commenced; for it is
at this moment that the course of our narrative is resumed. Mrs.
Beacham was delighting the assembly by a splendid display of her
musical talents; the major and Mr. Seymour were engaged in a game of
chess.
“There you sit, gentlemen,” exclaimed the vicar, “so absorbed in your
game, as to have remained quite insensible to the sweet sounds with
which Mrs. Beacham has been charming us; but you stand excused, for
Seneca admits the fascinating power of the ‘_ludus latrunculorum_,’ or
game of chess. You no doubt remember the story that he tells us of one
Canius Julius, who, having been sentenced to death by Caligula, was
found by the centurion, when he came to conduct him to execution, so
interested in a game of the ‘_latrunculi_,’ as at first to be
insensible to the summons, and that he did not prepare to depart until
he had counted his men, and desired the centurion to bear witness to
his having one more piece on the board than his adversary, so that the
latter might not boast of a victory after his death.”
“Indeed!” said the major; “but unfortunately for your story, the
ancients were not acquainted with the game of chess.”
“What absurd proposition am I next to expect?” cried Mr. Twaddleton.
“You surely cannot have read the poem to Piso, which some will have to
be Ovid’s, others Lucian’s: but no matter; it is an ancient poem, and
accurately describes the game of ‘_latrunculi_.’ I myself believe, from
a particular line in Sophocles, that chess was invented by Palamedes,
at the siege of Troy; although Seneca attributes it to Chilon, one of
the seven Grecian sages. My friend Mr. Seymour, who is, upon all
occasions, desirous of imparting wisdom through the medium of games,
and of ‘turning sport into science,’ will no doubt agree with those who
fancy that it was contrived by Pyrrhus, King of Epirus, as a method of
instructing his soldiers in the military art; and I must admit that the
game expresses the chance and order of war so very happily, that no
place can lay so just a claim to its invention as the camp: ‘_ludimus
effigiem belli_,’[71] as Vida says.”
“Check to your king!” cried the major; “while you are considering of
the best way to get his majesty out of the scrape, I will endeavour to
extricate the vicar out of the quagmire in which he is floundering. My
dear Mr. Twaddleton,” continued the major, “you speak as if it were an
admitted fact that the ‘_ludus latrunculorum_’ was synonymous with our
chess. I admit that it was a game played with _Tesseræ_ or squares, and
_Calculi_ or pieces; but it does not follow that it must have been
chess; indeed, the learned Dr. Hyde, whose researches into Oriental
games are as much distinguished for accurate discrimination as for
profound scholarship, considers it to have resembled our
_draughts_.”[72]
“You are to move, major,” said Mr. Seymour.
“Then I shall take your castle, and open a fresh battery upon the
vicar,” replied Major Snapwell.
“So you may,” cried Mr. Twaddleton, “but you will not easily drive me
from my position; supported as I am by Vossius and Salmasius, and an
army of valiant combatants.”
“The learned Hyde has endeavoured to prove that chess was first
invented in India, and passed from thence to Persia and Arabia.(54)
Fabricius considered it a Persian game, and I must say that I am
inclined to coincide with him. The terms in present use may evidently
be traced to an Oriental source. _Schach_, in the Persian language,
signifies king, and _schachmat_, whence our _check-mate_, the king is
dead, the original words having been transformed by progressive
changes; thus we have _schach_, _echecs_, _chess_; and by a whimsical
concurrence of circumstances, have arisen the English words _check_,
and _exchequer_.”
“I take your _queen_,” cried Mr. Seymour.
“Ay; and I take a _bishop_ in return,” said the major.
“Well,” observed the vicar, “if an Oriental nation really gave origin
to the game, it could not, at all events, have been China; since the
policy of that people is to exclude females from every kind and degree
of influence and power, whereas the _queen_ at chess is a powerful and
important piece.”
“You must not lay too much stress upon the names of the several
pieces,” observed the major, “since they have varied in different ages
and countries. The castle is sometimes called the _rook_, from the
Italian word _rocca_, which signifies a fortress placed on a rock: the
piece which we call the _Bishop_ has been termed by English writers
_alphan_, _aufin_, &c. from an Arabic word, signifying an elephant;
sometimes it was named an _archer_; by the Germans, the _hound_ or
_runner_; by Russians and Swedes, the _elephant_; by Poles, the
_priest_; and by the French, at a very early period, the _fou_ or
_fool_; the reason of this last appellation seems to be, that as this
piece stands on the sides of the king and queen, some wag of the times
styled it the _fool_, because anciently royal personages were commonly
thus attended, from want of other means of amusing themselves.”
“You cannot thus account for our term _bishop_,” observed Mr. Seymour,
“as our kings and queens have never had such attendants.”
“Nor is it very easy to ascertain the period at which it was
introduced,” replied the major; “in Caxton’s time it was styled the
_elphyn_. I should think it probable that the change of name took place
after the Reformation.”
“It is probable that the pieces not only underwent changes in name, but
changes in value or power,” observed Mr. Seymour, “as the game
descended through different ages and countries.”
Mrs. Beacham, who had been for some time listening with much interest
to the curious discourse we have just related, here ventured to ask a
question.
“As you appear to have taken some trouble to ascertain the origin of
this game, you can perhaps inform me at what period it was introduced
into England.”
The major replied, that the learned Hyde supposed it to have been first
known in our country about the time of the Conquest; but that Mr.
Barrington believed it to have been introduced during the thirteenth
century, upon the return of Edward I. from the Holy Land, where he
continued so long, and was attended by so many English.
“It is certain that our ancestors played much at chess before the
general introduction of cards,” observed the vicar, “as no fewer than
twenty-six English families have emblazoned chess-boards and
chess-rooks in their arms, and it must therefore have been considered a
valuable accomplishment.”
“Cards,” observed the major, “must have been known in England previous
to the time of Edward IV.; since a statute was passed in that reign
against their importation; but they did not become general for many
years, and the progress of the custom appears to have been extremely
slow.”
“Check,--and mate!” exclaimed Mr. Seymour.
“Upon my word, I have lost the game. Mr. Twaddleton, I lay this to your
account,” said the major; “you ought not, sir, to have intruded your
antiquarian discussions at such a time.”
“You have lost the game, major, because, like Charles XII. of
Sweden,[73] you are too fond of advancing your king; but it is quite
natural that you should feel mortified by your defeat: a person never
likes to be beat at chess, because it is a trial of skill and address;
chance has no place, and no one, therefore, loses except in consequence
of the superiority of adversary. You may remember that William the
Conqueror, upon being _check-mated_ by the Prince of France, knocked
the chess-board about his pate, an event which became the source of
much future enmity. I must say,” continued the vicar, “that this, in my
view of the matter, is an imperfection in the game; for, if it be the
type or representative of a military campaign, fortune should have some
share in deciding the fate of the day; and, if I remember correctly,
Sir William Jones has stated that the use of dice, to regulate the
moves, was formerly introduced in the East.”
“I will give the major his revenge whenever he pleases,” said Mr.
Seymour; “but as I well know how dearly the vicar loves an antiquarian
anecdote, if he will listen I will furnish him with one that will be
probably new to him. Do you observe the form of the chess-board,
resembling, as you perceive, two folio volumes?” said Mr. Seymour. “The
origin of it was this: Endes, bishop of Sully, forbade his clergy to
play at chess. As they were resolved, however, not to obey the command,
and yet did not dare to have a chess-board seen in their houses or
cloisters, they had them bound and lettered as books, and called them
their wooden gospels. These same monks had also drinking vessels bound
to resemble the breviary, and were found drinking when it was supposed
they were at prayers.”
-----
Footnote 70:
Many reasons have been assigned for this custom; the more commonly
received opinion is, that it was intended as a token of the
bridegroom having left off childish diversions, and entered on a more
serious state of life; whence _nucibus relictis_, has passed into a
proverb. This conjecture is favoured by Catullus:--
“Satis diu
Lusisti nucibus. Lubet
Jam servire Thalassio.”
We have already stated, that _nuces_ were played with like our
marbles; the custom, therefore, might be intended to express that the
bridegroom had deserted his playthings.
Footnote 71:
“War’s harmless shape we sing, and boxen trains
Of youth, encount’ring on the _cedar_ plains.
How two tall kings, by different armour known,
Traverse the field, and combat for renown.”
Footnote 72:
‘Ludus Latrunculorum;’ ludus, anglice dicitur _Draughts_, à trahendo
calculos.--HYDE _de Ludis Orientalium._ Oxon, 1694.
Footnote 73:
Voltaire tells us that Charles XII. always lost the game at chess,
from his eagerness to move his king, and to make greater use of him
than of any of the other pieces.
------------------------------------------------------------------------
CHAPTER XX.
_The arrival of the populace at Osterley Park.--The commencement
of the festivities.--Dancing on the Tight and Slack
Rope.--Balancing.--Conjuring.--Optical illusions.--Various
games.--The Penthalum.--The Banquet.--Grand display of
Fire-works.--Conclusion._
Never had the rosy fingers of Aurora shown so much reluctance in
unbarring the gates of the East, as on the morning of the Osterley
Jubilee; at least, so thought about half a score peasants, who, fevered
by anxiety and expectation, had arisen from their beds long before the
break of day.
At length, however, the sun arose; but indignant no doubt at the
accusations he had so unjustly suffered, he immediately veiled his
fiery countenance in dark and lowering clouds: here, then, was a fresh
source of doubt and anxiety; would the day be rainy? The gardener at
Overton Lodge was immediately sought and consulted; and cheering as
were his predictions, they scarcely succeeded in dispelling the gloom
which shaded many a fair countenance. The apprehension of
disappointment was, however, suddenly relieved; for between nine and
ten o’clock the sun re-appeared, beaming in all his glory, and shedding
the brightest refulgence on the scene of the approaching festivities.
At this period hundreds of villagers, dressed in their holiday attire,
were seen pouring along the high road, or winding their way through the
verdant valleys. So admirable had been the arrangements for the
admission of the populace into the park, that great as was the
concourse of spectators, not the slightest impediment occurred during
their entrance.
At half-past ten o’clock the whole population of the country had
assembled; the various performers were on their respective stages; and
the arrival of Major Snapwell and his guests was eagerly expected, as a
signal for the commencement of the festivities of the day.
At length a distant murmur was heard in the direction of the house,
which gradually increased as it approached the meadow, until it swelled
into one grand and universal chorus. The vicar appeared with his wand
of office, which he no sooner waved in the air than the murmur
gradually subsided. Major Snapwell and his friends, Harry Beacham and
his bride, and the Seymours with their children, and numerous visitors,
followed. The several bands, stationed on the platforms erected before
the show-booths, simultaneously struck up the national anthem, in which
the whole multitude joined, and produced one of the most surprising and
thrilling effects ever witnessed.
There were eight booths appropriated to the exhibitions; and it had
been arranged that each should commence at the same time, and repeat
its performances eight times during the day; so that by dividing the
spectators into eight groups, and delivering to each person a ticket
distinguished by a particular number, every spectator at once knew the
booth into which he was to enter; and having witnessed the exhibition,
he was directed to exchange his ticket; by which means every chance of
confusion was avoided, and each person was enabled to witness,
successively, every performance.
The vicar and the party entered the first booth, and were followed by
all those whose ticket was distinguished by No. 1.; those of No. 2. at
the same time entered the second booth, and so on.
The first show was appropriated to the various exhibitions of vaulting,
tumbling, balancing, and rope-dancing. The vicar expressed high delight
on observing that the stage was decorated with branches. “In the
ancient theatre,” said he, “the stage was originally planted with trees
to _shade_ the actors; hence scene, so called from the Greek word
signifying a shade.”[74]
During the performances of the balancer, Tom Seymour’s attention was
riveted on the artist; he watched every movement, and examined its
effect in preserving the centre of gravity within the base. “Papa,”
cried the delighted boy, “I never experienced so much interest in a
performance of this kind, until I was capable of explaining the
principles upon which it was conducted. I have attentively followed
every change of position, and discovered the effect of such changes
upon the line of direction.”[75] As to the _wire-dancing_, Tom
observed, that he saw very plainly the swinging of the wire backwards
and forwards diminished the difficulty, and assisted the actor in
keeping his equipoise.
Mr. Seymour was highly delighted with these remarks; and, casting an
intelligible look at Mr. Twaddleton, who was seated near him, he
exclaimed, “Well, vicar, you will surely now admit that the pleasures
which arise from sport are heightened by the admixture of science.”
“My dear Mr. Seymour,” replied the vicar, “you well know that I have
long since become a convert to your principles; I confess, however, had
that not been the case, the expression of satisfaction and delight
which have just fallen from my little playmate, Tom, would have removed
all my prejudices.”
“See, see!” exclaimed Louisa, “how very extraordinary! I declare that
the plate, sword, key, and tobacco-pipe, are all balanced as they
revolve on the chin of the performer.”
“And do you not know, Louisa,” replied Tom, “that the revolution of the
plate and sword, which appears to render the execution so much more
astonishing, actually diminishes the difficulty of the performance?”[76]
Thus did Tom Seymour continue to point out successively the
philosophical principles upon which each of the tricks might be
supposed to depend.
The next booth into which our party entered was that of Crank Smirky,
the celebrated conjuror, who invited the company to witness his
wonderful display of the art of legerdemain: he was dressed as an
astrologer, with a loose gown of green velvet, and a red cap; he had a
long grey beard, and his nose was bestraddled by a pair of green
spectacles.
“Ladies and gentlemen,” said the mystic professor, “I shall have the
honour of convincing you this day, that my single hand is more than a
match for all the sharp eyes of Overton. You will admit that a
beautiful eye makes silence eloquent,--a kind eye, contradiction an
assent,--and an enraged eye, beauty deformed; but my hand shall, by its
magic influence, make eloquence dumb, assent a contradiction, and
deformity beautiful.”
So saying, the professor beckoned a villager, who sat near the stage,
to approach and assist him in the performance of his first grand trick.
“Dobby,” exclaimed his terrified wife, “sit thee still; that man has
dealings with the old one; I would not that he should touch your
garment for all the gingerbread in the fair.”
This exclamation of the terrified wife set the whole audience in a
roar, and produced a confusion which the skilful conjuror is always
anxious to create, when any sly work is to be performed. In truth, this
scene had been previously concerted by the renowned Crank Smirky, who
had engaged this said Dobby as his confederate. A series of very
amusing tricks were then performed with cards and counters; such, for
instance, as desiring some person to draw a card from the pack, and
having observed what it was, to return it; which card, to the wonder of
the company, was immediately found in Dobby’s pocket. Mr. Seymour
informed his children that the explanation of this trick would serve to
show the manner in which most of the deceptions on cards were
performed. He said, that the conjuror’s pack of cards always contained
a card, technically termed a ‘_brief_ card,’ or ‘the _old gentleman_,’
which is one made on purpose by the card-maker, and is a little larger
than any of the rest; the performer always knows it by feeling it, and
can easily force it upon the unsuspecting drawer; should he, however,
attempt to take any other, the conjuror, under some pretence, shuffles
again, till at length he induces him to take the one intended for him.
After the card has been introduced again into the pack, the performer,
without any difficulty, withdraws it, and the confederate is called
upon to produce the duplicate which had been previously placed in his
pocket.
The children were told that the several deceptions with coin, or
counters, which they had witnessed, were accomplished by a species of
dexterity acquired only by practice, and termed ‘_palming_;’ it
consisted in being able to retain a shilling, halfpenny, or counter, in
the palm of the hand, while it remained extended; thus the performer
desires any one to reckon five pieces, which are accordingly placed on
the table before him, the conjuror then takes them up, and having
dexterously palmed one, he adds it to the number as he places it in the
hand of the unsuspecting person.
Tom and his sisters expressed themselves much pleased and surprised
with the dexterity of the performer; “But,” added the intelligent boy,
“I should be much more gratified by tricks that were indebted for their
mystery to some philosophical principle.”
Mr. Seymour and the vicar again interchanged looks that strongly marked
the feelings which had been excited by this observation. The former
turning to his son, said, that if he waited patiently, he would shortly
be gratified in that wish, for he knew Crank Smirky was prepared to
exhibit some recreations in divination, that were founded on the
science of numbers.
Nor was Mr. Seymour mistaken; for after a few more specimens of his
dexterity, the conjuror requested Mr. Twaddleton, who was sitting
directly in his front, to take an _even_ number of counters in one
hand, and an _odd_ number in the other; and he would tell him, he said,
in which hand he held the even number. Mr. Twaddleton having complied
with the request, he was farther desired to multiply the number in the
right hand by any _even_ number he pleased, as, for instance, 2; and
that in the left hand by an odd number, as 3.
“I have done so,” said the vicar.
“Then be pleased to add together the two products, and tell me whether
the sum be odd or even.”
“It is odd,” replied Mr. Twaddleton.
“If so,” said the conjuror, “the even number of counters will be in
your right hand.”
The vicar exposed the counters, and admitted the correctness of the
conjuror’s decision.(55)
“Ladies and gentlemen,” exclaimed the man of mystery, “I now humbly
crave your silent attention, while I exhibit one of the most wonderful
examples of my art. Here is a ring,--there a shilling,--and there a
glove. I shall presently request each of the three gentlemen before me,
to take one of those articles, so secretly as to prevent the
possibility of my discovering the choice he may have made. I have here,
you perceive, twenty-four counters; _one_ of which I shall give to you,
Mr. Seymour; _two_ to you, reverend sir; and _three_ to you, my young
philosopher; the remaining eighteen shall remain on the table. Now,
gentlemen, I shall retire, and during my absence, you will be so good
as to distribute the three articles in any way you may think proper.”
The professor, accordingly, walked off the stage; when Mr. Seymour took
the ring; the vicar the shilling; and Tom Seymour the glove. The
conjuror, on his return, said that he had one more favour to request,
that the person who had the ring should take from the eighteen counters
on the table as many as he already possessed; the one with the shilling
twice as many; and the person with the glove, four times as many as he
before possessed. The conjuror again retired, in order that the
distribution might be made without his observing it. On returning, the
conjuror, having first cast his eye upon the counters that remained on
the table, informed the company that Mr. Seymour had taken the ring,
Mr. Twaddleton the shilling, and the young gentleman the glove. The
moment the parties assented to this decision, the whole company
expressed their satisfaction and astonishment by thunders of applause.
“That is really very ingenious,” observed the vicar.
“How could he perform it?” said Tom: “it is evident that his only guide
was the number of counters left on the board.”
“I understand the process by which it was accomplished, and will
endeavour, at some future time, to explain it,” replied Mr. Seymour.(56)
A number of similar tricks followed, all of which depended upon some
algebraical calculation; and the performance was concluded to the
entire satisfaction of all present.
The next exhibition was of a very different character: it consisted in
a variety of optical representations and illusions. The camera obscura
presented a moving picture of the surrounding scene. The phantasmagoria
exhibited a variety of ghastly objects, which alternately receding
from, and approaching the audience, called forth shrieks of terror and
amazement. Amongst the most appalling of these figures, was the
headless horseman of Sleepy Hollow, so inimitably described in the
Sketch Book: it will be remembered that the body of this trooper having
been buried in the church-yard, its ghost was believed to ride forth
every night in quest of its head, and that the rushing speed with which
he passed along the hollow, like a midnight blast, was owing to his
being in a hurry to get back to the church-yard before day-break. This
rapid movement was admirably represented in the phantasmagoria: at
first the figure appeared extremely diminutive, and at a great
distance; but almost immediately its size became gigantic, and it
seemed as if within a few feet of the audience, and then suddenly
vanished. After an instant of utter darkness, the figure was again
visible at a great distance: the schoolmaster, Crane, was also seen
belabouring the starveling ribs of his steed, old Gunpowder, and
quickening his pace towards the very spot where the spectre was
stationed. The whole audience were breathless with horror. Crane
arrived at the bridge, over which the headless figure opposed his
passage. “Mercy upon us!” cried a faint voice from one of the back
seats, “the ghost has found his head, and is carrying it before him on
the pommel of his saddle.”--“Hush, hush!” cried another voice; Crane’s
horse had taken fright; away he dashed through thick and thin; stones
flying and sparks flashing at every bound. Crane’s flimsy garments
fluttered in the air, as he stretched his long lank body away over his
horse’s head, in the eagerness of his flight. The goblin pressed hard
upon him; he was not more than a yard behind him, when he was seen to
take up his head, and with gigantic force to hurl it at the pedagogue;
it encountered his cranium with a tremendous crash; he was tumbled
headlong in the dust; the goblin whisked past like a whirlwind, and the
company were once again in total darkness.
“Upon my word,” exclaimed Mr. Seymour, “this is one of the most
complete illusions I ever witnessed.”
“It is most ingeniously managed,” said the vicar.
“Papa,” cried Tom, “I am quite impatient to learn how so extraordinary
an effect can have been produced. You told me this morning that a
phantasmagoria was nothing more than an improved magic lantern; but how
is it possible for the slides to be so managed as to make the figures
approach and retire from you, and above all, to make them move their
bodies, and throw their arms into different attitudes?”
“In the first place, the figures only _appear_ to approach you, for
they are thrown upon a surface which never changes its place; the whole
is therefore an optical illusion, arising from the fact that we
estimate the distance of an object by its apparent magnitude; when,
therefore, the figure began to diminish in size, the mind instantly
assumed that it was receding from the eye; and the illusion was still
farther heightened by the absence of all other objects[77] by which it
might be compared.”
At this moment Mr. Seymour was interrupted by the appearance of the
performer who announced his intention of submitting another optical
illusion, which, he trusted, would afford equal satisfaction.
“Papa,” cried Tom, “how much do I regret my ignorance of optics. It is
a great disappointment to me that I should witness so many curious
exhibitions, without being able to understand the principles upon which
they depend.”
“I promise you, my dear boy,” replied Mr. Seymour, “that you shall be
instructed in this branch of science during the Christmas vacation.
Enjoy, therefore, the present amusements, and instead of repining at
your ignorance, anticipate the pleasure which you will receive, when
you shall be able to explain them.”
A series of extraordinary effects were now exhibited by means of
concave mirrors.[78] Aërial images were produced, so illusive in their
appearance, that the spectators could not believe in their
immateriality, until they attempted to grasp them. In this manner were
presented flowers, fruit, a human skull, and a dagger; the latter of
which terrified the spectator by the sudden and violent manner in which
its point approached him. With this illusion the amusements concluded;
the light of day was admitted; and the performer stepping forward,
announced the termination of his exhibition in the words of
Shakspeare:--
“Our revels now are ended: these our actors,
As I foretold you, were all spirits, and
Are melted into air, into thin air.”
The villagers, as they poured out of the booth, and mingled with their
companions in the fair, with their wonted propensity for the
marvellous, related, in most exaggerated terms, the wonders they had
encountered in the region of shadows. Nothing is swallowed with more
avidity than tales of mystery, especially if spiced with a few grains
of horror; we cannot, therefore, be surprised at the anxiety so
generally by those who had not yet witnessed the optical performances
to exchange their tickets for such as would secure their admission into
the popular booth.
The next entertainment was a display of ventriloquism, by a pupil of
the celebrated Baron de Mengen.
“Now,” said the vicar, “we are to witness a deception upon the ear,
such as we have just seen practised on the eye.”
Mr. Twaddleton was quite correct in this observation; for,
notwithstanding all the mystery with which the subject has been
invested by credulity, ventriloquism is nothing more than a skilful
modulation of the voice, so as to imitate the gradations of sound, as
they effect the ear in nature under all the circumstances of distance
and obstruction; in short, imposing upon the ear as a perspective
painting does upon the eye.
The crowd which had assembled round the spot was now dispersed by the
appearance of a placard, announcing the suspension of all the
performances for two hours; and informing the populace that the
interval would be devoted to various sports and pastimes in the
adjoining field.
The revellers accordingly hastened to the spot where the several sports
were to take place, and to which they were directed by the sound of a
bugle.
We have stated that a small enclosure had been prepared for the youths
of the village, who were to perform the “_ludus Trojæ_,” or Troy game.
The major and his party had taken possession of the seat, placed for
their accommodation under an awning; and the boys, classically dressed,
and furnished with little arms and weapons, were mustered in _circo_.
Each youth was mounted on a pony; and the troop having rode round the
ring, and surveyed the spectators, the vicar arose from his seat, and,
like the sage Epytides, gave the signal of attack by a crack of the
whip. They now arranged themselves in two battalions, and hurling their
javelins with an air of proud defiance, wheeled and charged, and urged
the sportive war; at the conclusion of the game, the vicar called the
principal youth, or “_princeps juventutis_,” and presented him with a
basket of fruit, which he desired him to divide amongst his companions.
The populace now separated into different groups; one party proceeded
to witness a wrestling-match; another to see the foot-race; a third to
be present at a match of quoits; for the vicar had provided all these
games, in imitation of the ancient _Penthalum_ or _Quinquertium_. While
observing the game of quoits, the vicar displayed much classical
erudition; he said that Homer had represented Ajax and Ulysses as
greatly skilled in the sport; and that Ovid, when he brings in Apollo
and Hyacinth playing at it, had given a very elegant description of the
exercise.[79] Scaliger, he continued, is of opinion, that the throwing
the _discus_, or quoit, is but an improvement of the old sport of
casting the sheep-hook; a conjecture which, the vicar thought, received
some support from a passage in the fourth Iliad.
“Mr. Twaddleton,” cried Mr. Seymour, “you look at every sport with the
eye of a classic or antiquary; I, on the other hand, as you well know,
cautiously examine every action, to discover whether some scientific
principle may not find an illustration. On the present occasion, I am
desirous of directing the attention of the children to the manner in
which yonder skilful player hurls his quoit.”
“I do not exactly comprehend the object they have in view in throwing
the quoits,” said Louisa.
“Do you not perceive that two iron pins, or _hobs_, are driven into the
ground, at the distance of eighteen or twenty yards asunder?” asked her
father.
“To be sure, and I suppose that each player attempts to hit one of
those pins.”
“The players stand at one of the _hobs_, and throw an equal number of
quoits at the other; the nearest of them to the hob are reckoned
towards the game. When they have cast all their quoits, the candidates
go over to the point at which they have been throwing, and when they
have determined the state of the game, they throw their quoits back
again at the hob where they had before stood; and thus continue to act,
on alternate sides, till the game is ended.”
“I now understand it,” cried Louisa.
“You doubtless know, Mr. Twaddleton,” said Mr. Seymour, “that the
casting of stones, darts, and other missiles, was among the amusements
practised in the twelfth century by the young Londoners.”
“_Casting of the bar_,” replied the vicar, “was formerly a part of a
hero’s education; and kings and princes were admired for their agility
and grace in throwing ‘the stone, the bar, and the plummet.’ Henry the
Eighth, even after his accession to the throne, retained the casting of
the bar among his favourite amusements. The sledge-hammer, and, among
rustics, an axle-tree, were also used for the same purpose as the bar
and the stone.”
“The game of quoits is certainly far superior to such pastimes,” said
Mr. Seymour, “on account of its depending less on mere strength, and
more upon superior skill.”
“Did not you say, papa, that its action would illustrate some principle
of science? I have been looking at the quoit, which I perceive is a
circular piece of iron with a hole in the middle, but I cannot discover
in what manner any scientific principle can be connected with its
motion.”
“If you will attentively observe a skilful player, you will perceive
that he steadies the flight of the quoit, by imparting to it a spinning
motion; were he not thus to _rifle_ it, you would find that it would
fly very far from the mark.”
“Upon the same principle, I suppose, that we impart to the ball a
spinning motion at the game of _bilboquet_?”
“Precisely so,” replied her father, who also stated that the body was
made to rotate on its shortest axis, for the reasons before
explained.[80]
The “_penthalum_” having been concluded, the populace retired into
several booths which were appropriated to refreshments. The shows then
re-commenced; those not already described were principally devoted to
the exhibition of wild animals, an entertainment which the vicar
considered as sanctioned by the highest classical authority; although
he, at once, rejected a proposition made by the major, to render the
amusement still more in accordance with ancient custom, by encouraging
a fight between a lion and a tiger.
The hour had now arrived for the grand banquet; and, by the command of
the major, the band paraded the fair, playing the inviting tune of “Oh,
the roast beef of Old England.” The populace hastened to the tent, and
each took his place according to the number upon his ticket.
We shall not detain our readers by an account of the dinner; it will be
sufficient to state, in the language generally used upon such
occasions, that the whole went off with great eclat, and gave universal
satisfaction to the delighted guests.
For the amusement of his military friends, the major had made
arrangements for reviving the ancient game of quintain. It may be
necessary to state that the quintain is a pastime of high antiquity. It
was originally nothing more than the trunk of a tree, or a post set up
for the practice of young beginners in chivalry. Afterwards a staff, or
spear, was fixed in the earth, and a shield, hung upon it, was the mark
to strike at. The dexterity of the performer consisted in smiting the
shield in such a manner as to break the fastening and to bring it to
the ground. In process of time, this diversion was much improved;
instead of the staff and shield, a grotesque wooden figure was
introduced, and it was so contrived to move upon a pivot, that if it
were struck unskilfully, it would turn out and give the performer a
severe blow. The quintain which the major had prepared for the present
occasion consisted of a wooden figure, fixed upon a pivot, and holding
in its outstretched arm a bag of flower. Those who ran at it, and
missed it, were of course laughed at; while those who struck the figure
full with his lance gave the beam a sudden whirl; and unless he was
very nimble, was covered with flower from the bag which was thus
brought into contact with him.
The reader must now be contented to retire from the scene of frolic,
and leave the villagers to the undisturbed enjoyment of their jollity.
The major and his party returned to the house, where they remained
until the hour approached at which the fire-works were to be
discharged, and the festivities of the day concluded. Mr. Seymour
accompanied his children to the stage, erected for the pyrotechnic
exhibition, in order that he might explain the construction of the
fire-works before they witnessed them in action.
“Upon my word, the major has provided most liberally for our
entertainment!” exclaimed Mr. Seymour, as he ascended the steps which
led to the platform. “I declare there is a forest of _rockets_! and
what magnificent _Pin-wheels, Tourbillions, Marroons, Pots des
Aigrettes, Gerbes, Courantins, and Roman Candles_.”
“Are those paper cylinders, with long sticks, rockets?” enquired Tom.
“They are; and if you will attend to me, I will explain the principle
of their construction. They have ever been considered as holding the
first place amongst single fire-works, and deservedly so; not only on
account of the splendid appearance they present when fired by
themselves, but from their extensive application in increasing the
beauty of other exhibitions. The rocket, you perceive, consists of a
strong paper cylinder, which is filled with a suitable composition; it
is crowned with a head, or ‘_pot_,’ as it is technically termed,
charged with various materials, which throws out sparks, stars, and
other decorations, as soon as it takes fire in the air, after the body
of the rocket has been consumed. You may observe that the head is made
to terminate in a point, which greatly facilitates its passage through
the air. The whole is affixed to a straight stick, which, like the
rudder of a ship, makes it turn to that side towards which it is
inclined, and consequently causes the rocket to ascend in a straight
line.”
“But, papa,” observed Louisa, “all the rockets have not straight rods;
see, there is one, with a crooked stick.”
“That is for the purpose of causing the rocket to ascend in the form of
a screw: the first effect of the bent rod will be to make the rocket
incline towards that side to which it is bent; but its centre of
gravity bringing it afterwards into a vertical situation, the result of
these two opposite efforts will be, that the rocket will ascend in a
zig-zag or spiral form. In this case, however, since it displaces a
greater volume of air, and describes a longer line, it will not ascend
so high as if it had been impelled in a straight direction; but I think
you will admit that, on account of the singularity of this motion, it
produces a very agreeable effect.”
“And what causes the rocket to ascend into the air?” asked Tom.
“It is a subject which has engaged the attention of several most
distinguished philosophers; the explanation, however, offered by Dr.
Hutton appears to me to be the most satisfactory. He says, ‘that at the
moment when the powder begins to inflame, its expansion produces a
torrent of elastic fluid, which acts in every direction; that is,
against the air which opposes its escape from the cartridge, and
against the upper part of the rocket; but the resistance of the air is
more considerable than the weight of the rocket, on account of the
extreme rapidity with which the elastic fluid issues through the neck
of the rocket to throw itself downwards, and therefore the rocket
ascends by the excess of the one of these forces over the other.’”
Tom observed, that he thought Dr. Hutton’s explanation very simple and
plausible.
“Dr. Hutton adds,” continued Mr. Seymour, “that the rocket could not
rise unless a sufficient quantity of elastic fluid were produced, and
hence arose the expedient of piercing the rocket with a conical hole,
so as to make the composition burn in conical strata, which, having
much greater surface, produce a much greater quantity of inflamed
matter and elastic fluid. Without such a contrivance, the composition
would inflame only in circular coats of a diameter equal to that of the
rocket; and experience has shown that this is not sufficient for the
purpose. Some years ago a plan was suggested for producing the
propulsion of a vessel in this way; by the force of a steam-engine, a
stream of water was to be shot out of the stern, the impulse of which,
upon the water in the river, was to push forward the boat. It is a
curious fact, that Nature has employed the same expedient for the
motion of some aquatic insects. The larva of the dragon-fly, according
to Adams, swims forward by ejecting water from its tail.”
“What are those fire-works, attached to the lines?” asked Tom.
“Those, my dear, are line-rockets, or _courantines_,[81] and which,
instead of rising into the air, run along the line, to which they are
attached by means of a hollow cylinder. Their motion is to be explained
upon the same principle as that of the sky-rocket; a force is generated
by the escape of elastic matter, and as the rocket is confined to the
rope, it is made to run along the line, instead of ascending into the
air.”
“That is clear enough,” said Louisa; “but see, papa, there is the
figure of a dragon on yonder rope!”
“That is merely a runner for the courantine, which is constructed in
that form, for the purpose of rendering the exhibition more surprising.
I dare say it is filled with various compositions, such as golden rain,
and fires of different colours, which will greatly heighten the effect:
indeed this pyrotechnic amusement may be infinitely varied.”
“Are not those _pin-wheels_, which are elevated above the railing?”
said Tom.
“Yes; they are pin or Catharine wheels, and if you will look at them,
you will perceive that they are of very simple construction; consisting
merely of a long paper tube, filled with inflammable matter, and rolled
round a small circle of wood, so as to form a helix or spiral line.”
“The circle of wood, I suppose, is pierced in the middle for the
purpose of receiving a pin, by which the wheel is attached to the
post,” said Tom.
“Exactly so; and the cause of their revolution is the same as that
which produces the flight of the rocket; the impulse of the air forces
back the ignited part of the wheel, which generates, as it were, a
centrifugal force, while the attachment of the pipe, by preventing its
obeying such a force, may be said to represent the centripetal force,
and thus is the revolution of the wheel continued, until the whole of
the composition is consumed.”
“I think you told us, when speaking of the thaumatrope,[82] it was the
rapidity with which the flame revolved, that occasioned the star-like
appearance which is exhibited by this fire-work,” observed Louisa.
“Undoubtedly, my dear; it cannot be otherwise.”
The party now examined the remaining specimens of the pyrotechnic art.
Mr. Seymour informed them that _marroons_ were nothing more than small
cubical boxes, filled with a composition proper for making them burst,
and thence producing a loud report. He said that they were principally
used in combination with other pieces, or to form a battery, in which,
by different lengths of quick match, they were made to explode at
distinct intervals. Mr. Seymour added, that when the cases were made
cylindrical, instead of being cubical, they exchanged the name of
marroon for that of _saucisson_. Louisa enquired the nature of certain
cylindrical cases she observed on the stage, and was informed that they
were _gerbes_, a species of fire-work, which throws up a luminous and
sparkling jet of fire, and from a supposed resemblance to a
water-spout, has derived the appellation of _gerbe_. Mr. Seymour next
pointed out to Tom a row of _Roman candles_, some of which were fixed
quite perpendicular, others inclining at different angles, so that the
balls might be projected to various distances, and thus produce a more
varied effect. He observed, that, to his taste, it was by far the most
beautiful fire-work ever exhibited.
“I am quite impatient for the exhibition,” cried Tom; “pray, papa, what
is the hour? I think it was determined to let them off at ten o’clock.”
“It is now about eight o’clock; we will, therefore, return to the
house: we shall, however, I suspect, have a curious sight to witness in
our way through the fair; for by this time every booth is illuminated.”
The scene was indescribably beautiful, and might be said to resemble an
enchanted island. The trees were lighted up with an endless profusion
of Chinese lanterns, of various colours, and decorated with fantastic
transparencies, which produced an effect highly graceful and pleasing.
The booths were richly studded with lights; and, near the platform, on
which the villagers were enjoying the country dance, was erected a
pyramid, which blazed with several hundred variegated lamps.
At ten o’clock the commencement of the fire-works was announced by a
shower of rockets. The music ceased; and the dancers, together with the
spectators who had gathered around the platform, hastened to the spot,
whither they were summoned by the sound of trumpets, to witness the
pyrotechnic entertainment which was to crown the festivities of the day.
The little Seymours had been stationed by their father in the most
favourable spot for seeing the exhibition; and highly were the major
and his party delighted with the observations which fell from the
intelligent children on the occasion.
“Observe, Louisa, the rocket as it ascends describes a parabola,”[83]
cried Tom.
“Oh, how extremely beautiful! see, the head has burst, and is
discharging a number of brilliant stars! What is that red spark which
is now falling to the ground, papa?”
“That is the ignited stick of the rocket,” replied his father.
“Take care, Louisa, do not hold your face up,” exclaimed Tom; “for as
the rocket bursts over our heads, the stick may fall upon us.”
“I scarcely expected such an observation from you, Tom,” said his
father, “after the sensible remark you just made respecting the
parabolic path of the rocket; do not you remember, that when a
projectile has reached its greatest altitude, it will descend in a
curve similar to that in which it ascended?”
“True, true,” answered Tom; “I see my error; the stick must, of course,
fall at a considerable distance from us.”
“Look! look!! There goes a _courantine_: how it ran along the rope!”
exclaimed Louisa.
“There goes another!” cried Tom; “and see, it is the dragon; and I
declare there is another running in an opposite direction;--they meet.
Look at the serpents which they discharge from their mouths! Now they
return to the extremity of the line with great violence. What an
explosion!!!”
In like manner were next exhibited two ships, which, being filled with
serpents, were made to pour their broadsides at each other.
“I never saw better courantines in my life,” said Mr. Seymour; “the
major really conducts the exhibition with great skill; it does him
infinite credit as an engineer.”
“See--see, papa! what a large wheel of fire!” exclaimed Tom, “and the
figure of a man in the centre.”
“A classical device of the vicar beyond all doubt. It is Ixion on a
wheel encompassed by hissing serpents,” observed his father.
This conjecture was soon verified, for the vicar with his usual
animation was heard to exclaim--
________“tortosque Ixionis angues,
Immanemque rotam,”
as Virgil has it.
Another shower of rockets succeeded, and the air resounded with the
applause of the populace.
(Bang)--(bang)--(bang)--
“There go the marroons,” said Mr. Seymour.
The band now struck up a march, and the major completely succeeded, by
having arranged different lengths of quick match, in making them
explode at appropriate intervals, so as to mark correctly the
commencement of each bar of the music which was performing.
“Bravo! bravo!” exclaimed Mr. Seymour; “had Handel witnessed such an
effect, he would have engaged the major as a performer in his grand
choruses.”
“See! what a beautiful fountain of fire--there! now a most brilliant
star is ejected!”--
“It is a Roman candle,” said Mr. Seymour.
A variety of different rockets were next exploded; such as “_Towering_
rockets,” so called from their ascending to a greater height than any
others; an effect which is produced by fixing a smaller rocket on the
top of another of superior dimensions; “_Honorary_ rockets,” which,
when they attain their greatest height, communicate fire to other
rockets affixed to them in a transverse direction, and thus produce a
rapid revolution, and represent, on their return to the ground, a
spiral of descending fire; “_Caduceus_ rockets,” so called from their
resemblance, when in action, to the rod borne by Mercury: the effect is
produced by firing two rockets obliquely on the opposite sides of a
rod, so that they shall form in their flight two spiral lines.
It is not necessary to enumerate the series of beautiful exhibitions
which succeeded; we shall only add, that the concluding fire-work was a
Catharine-wheel of imposing splendour. After having repeatedly changed
its device and colours during its revolution, it at length exploded and
threw out a group of serpents; the dense volume of smoke which followed
this explosion, gradually cleared off, and the appropriate motto of
“FAREWELL,” appeared in brilliant letters of red fire.
In a few minutes, the populace began to separate; they had, however,
scarcely arrived at the gate of the park, when a large rocket ascended,
and bursting over their heads, discharged a parachute, to which was
attached a brilliant light; eight similar rockets were successively
fired, and with the same effect. The major had ingeniously contrived,
by varying the angle, to disengage the floating luminaries in the form
of a crown or circle, which threw a blazing light over the whole
country; nor did it fade until sufficient time had been allowed for the
return of the villagers to their respective homes.
Should our readers have fortunately been infected with a portion of
that good humour and hilarity which elated the hearts of the spectators
upon this memorable occasion, we may conclude our labours with the
cheering hope that they will receive a favourable reception at the
tribunal of public opinion.
[Illustration: Floating luminary.]
-----
Footnote 74:
Σκηνὴ
Footnote 75:
See p. 69.
Footnote 76:
See p. 84.
Footnote 77:
It is to this latter circumstance that the Panorama is principally
indebted for its magical effects.
Footnote 78:
Sir David Brewster has enumerated various extraordinary illusions,
which may be thus produced, in his Work on Natural Magic.
Footnote 79:
Ovid’s Metamorphoses, 10.
Footnote 80:
Page 138.
Footnote 81:
From the French term _courant_, signifying running.
Footnote 82:
See page 344.
Footnote 83:
A scientific critic has offered the following just remark upon this
passage. “The rocket ascends by a constantly acting force, not by a
momentary impulse, as though it were shot from a gun. Supposing the
force arising from combustion to be proportionate to the weight of
the rocket, as long as the force continues to be generated, the
rocket must move in a straight line; after which, having only its own
momentum to oppose its gravitation, it will proceed in a parabolic
curve.”
------------------------------------------------------------------------
ADDITIONAL NOTES;
ADDRESSED MORE ESPECIALLY TO
PARENTS AND PRECEPTORS,
OR TO
THOSE ADVANCED IN SCIENCE.
------------------------------------------------------------------------
CONTENTS OF THE NOTES.
_Note_ _Page_
1. 409. Horologe of Flora.
2. 410. Gravity and centrifugal force.
3. 411. Velocity of light.
4. 412. Velocity of falling bodies.
5. 412. Hydromancy.
6. 414. Coins and medals.
7. 421. Why bodies revolve on the shorter axis.
-- 421. Vis inertiæ.
8. 422. Mechanical powers.
9. 423. Centre of gravity.
10. 423. The Indian blow-pipe.
11. 425. Springs.
12. 427. Elastic chairs and beds.
13. 428. Duck and drake.
14. 428. Vegetable elasticity.
15. 428. A simple orrery.
16. 429. Conic sections.
17. 429. Earthquake of Lisbon.
18. 429. Geology applied to agriculture.
19. 430. Buckland’s researches.
20. 436. The rifle.
21. 438. Centre of percussion.
22. 438. Spinning of the top.
23. 439. The mechanical powers.
24. 446. The cycloid.
25. 447. Billiards.
26. 448. Collision of bodies.
27. 450. Druidical remains.
28. 456. Animal suction.
29. 459. Accidental discoveries.
30. 461. Weight of the superincumbent ocean.
31. 462. _Pecunia_; its derivation.
32. 462. Cause of iridescence.
33. 463. Vegetable barometers.
34. 463. St. Swithin.
35. 464. The whale.
36. 465. Progressive motion in fishes.
37. 466. Flight of birds.
38. 466. Flight of insects.
39. 466. Obliquity of the wings of birds.
40. 467. A mechanical proposition.
41. 467. Kite messengers.
42. 467. Wind.
43. 470. Ancient archery.
44. 472. Sound conveyed by solids.
45. 473. Expressive music.
46. 473. Imaginary forms.
47. 474. Fairy rings.
48. 475. Resonance.
49. 477. Jew’s harp.
50. 478. Verbal telegraph.
51. 479. Electrical telegraph.
52. 479. Carrier pigeons.
53. 481. Origin of popular ceremonies.
54. 482. Chess.
55. 483. Arithmetical trick.
56. 484. A problem in algebra.
------------------------------------------------------------------------
ADDITIONAL NOTES
REFERRED TO BY FIGURES IN THE TEXT.
---------------------
Note 1, p. 4.--THE HOROLOGE OF FLORA.
THE HOROLOGE OF FLORA is alluded to by Pliny with his usual felicity of
thought and expression. “Dedi tibi herbas horarum indices; et ut ne
sole quidem oculos tuos a terra avoces, heliotropium ac lupinum
circumaguntur cum illo. Cur etiam altius spectas, ipsumque cœlum
scrutatis? Habes ante pedes tuos ecce Vergilias.”--_Hist. Nat._ lib.
xviii. c. 27.
Linnæus enumerates forty-six flowers which possess this kind of
sensibility. The following are a few of them, with their respective
hours of rising and setting, as the Swedish naturalist terms them. He
divides them into _meteoric_ flowers, which less accurately observe the
hour of unfolding, but are expanded sooner or later, according to the
cloudiness, moisture, or pressure of the atmosphere.
2nd. _Tropical_ flowers, which open in the morning, and close before
evening every day; but the hour of the expanding becomes earlier or
later, as the length of the day increases or decreases.
3rd. _Equinoctial flowers_, which serve for the construction of Flora’s
dial, since they open at a certain and exact hour of the day, and for
the most part close at another determinate hour: for instance, the
_Leontodon Taraxacum_, dandelion, opens at 5-6, closes at 8-9;
_Hieracium Pilosella_, mouse-ear hawkweed, opens at 8, closes at 2;
_Tragopogon pratensis_, yellow goat’s-beard, opens at sunrise, and
shuts at noon with such regularity, that the husbandman who adopts it
as the signal of dinner-time need not fear to have his pudding too much
or too little boiled; _Sonchus lævis_, smooth sow-thistle, opens at 5,
closes at 11-12; _Lactuca sativa_, cultivated lettuce, opens at 7,
closes at 10; _Tragopogon luteus_, yellow goat’s-beard, opens at 3-5,
closes at 9-10; _Lapsana_, nipplewort, opens at 5-6, closes at 10-11;
_Nymphæaalba_, white water-lily, opens at 7, closes at 5; _Papaver
nudicaule_, naked poppy, opens at 5, closes at 7; _Hemerocallis fulva_,
tawny day-lily, opens at 5, closes at 7-8; _Convolvulus_, opens at 5-6;
_Malva_, mallow, opens at 9-10, closes at l; _Arenaria purpurea_,
purple sandwort, opens at 9-10, closes at 2-3; _Anagallis_, pimpernel,
opens at 7-8; _Portulaca hortensis_, garden purslain, opens at 9-10,
closes at 11-12; _Dianthus prolifer_, proliferous pink, opens at 8,
closes at 1; _Cichoreum_, succory, opens at 4-5; _Hypocharis_, opens at
6-7, closes at 4-5; _Crepis_, opens at 4-5, closes at 10-11; _Picris_,
opens at 4-5, closes at 12; _Calendula Africana_, opens at 7, closes at
3-4, &c.
“Thus in each flower and simple bell,
That in our path betrodden lie,
Are sweet remembrancers who tell
How fast the winged moments fly.”
In like manner may be formed a _calendar_ of Flora: thus, if we
consider the time of putting forth leaves, the _honeysuckle_ protrudes
them in the month of January; the _gooseberry_, _currant_ and _elder_,
in the end of February, or beginning of April; the _oak_ and _ash_ in
the beginning, or towards the middle of May, &c.
Note 2, p. 32.--GRAVITY AND CENTRIFUGAL FORCE.
It may, perhaps, be asked how this decrease of weight could have been
ascertained; since, if the body under examination decreased in weight,
the weight which was opposed to it in the opposite scale must also have
diminished in the same proportion; for instance, that if the lump of
lead lost two pounds, the body which served to balance it must also
have lost the same weight, and therefore that the different force of
gravity could not be detected by such means. It is undoubtedly true
that the experiment in question could not have been performed with an
ordinary pair of scales, but by using a spiral spring it was easy to
compare the force of the lead’s gravity at the surface of the earth,
and at four miles high, by the relative degree of compression which it
sustained in those different situations. We may take this opportunity
of observing, that as the force of gravity varies directly as the mass,
or quantity of matter, a body weighing a pound on our earth would, if
transferred to the sun, weigh 27-3/4 pounds; if to Jupiter, 3-1/10
pounds; if to Saturn, 1-1/9; but, if to the moon, more than three
ounces.
With respect to the effect of the centrifugal force as alluded to in
the text, it may be here observed, that it has been found by
calculation that, at the equator, the diminution of gravity occasioned
by the centrifugal force arising from the rotation of the earth,
amounts to about the 289th part. But since this number is the square of
17, it follows, that, if our globe turned more than 17 times faster
about her axis, or performed the diurnal revolution within the space of
84 minutes, the centrifugal force would predominate over the powers of
gravitation, and all the fluid and loose matters would, near the
equinoctial boundary, have been projected from the surface. On such a
supposition the waters of the ocean must have been drained off, and an
impassable zone of sterility interposed between the opposite
hemispheres. By a similar calculation, combined with that decreasing
force of gravity at great distances from the centre, it may be
inferred, that the altitude of our atmosphere could never exceed 26,000
miles. Beyond this limit, the equatorial portion of air would have been
shot into indefinite space. If it were possible to fire off a cannon
ball with a velocity of five miles in a second, and the resistance of
the air could be taken away, it would for ever wheel round the earth,
instead of falling upon it; and supposing the velocity to reach the
rate of seven miles in a second, the ball would fly off from the earth,
and be never heard of more.
Note 3, p. 35.--VELOCITY OF LIGHT.
It is scarcely possible so to strain the imagination as to conceive the
velocity with which light travels. “What mere assertion will make any
man believe,” asks Sir W. Herschel, “that in one second of time, in one
beat of the pendulum of a clock, a ray of light travels over 192,000
miles, and would therefore perform the tour of the world in about the
same time that it requires to wink with our eyelids, and in much less
than a swift runner occupies in taking a single stride?” Were a cannon
ball shot directly towards the sun, and it were to maintain its full
speed, it would be twenty years in reaching it, and yet light travels
through this space in seven or eight minutes.
Note 4, p. 36.--VELOCITY OF FALLING BODIES.
In order to perform this experiment with the highest degree of
accuracy, a body of considerable specific gravity should be selected,
such as lead or iron; for a common stone experiences a considerable
retardation in falling, from the action of the air. Where the arrival
of the body at the bottom of the cavern to be measured cannot be seen,
we must make allowance in our calculation for the known velocity of
sound; thus, suppose a body were ascertained to fall in five seconds.
As a heavy body near the earth’s surface falls about 16-1/12 feet in
one second of time, or for this purpose 16 feet will be sufficiently
exact; and as sound travels at the rate of 1142 feet per second,
multiply together 1142, 16, and 5, which will give 91360, and to four
times this product, or 365440, add the square of 1142, which is
1304164, and the sum will be 1669604; then if from the square root of
the last number = 1292 the number 1142 be subtracted, the remainder 150
divided by 32 will give 4.69 for the number of seconds which elapsed
during the fall of the body; if this remainder be subtracted from 5,
the number of seconds during which the body was falling and the sound
returning, we shall have 0.31 for the time which the sound alone
employed before it reached the ear; and this number multiplied by 1142,
will give for product 354 feet equal the depth of the well. This rule,
which, it must be allowed, is rather complex, is founded on the
property of falling bodies, which are accelerated in the ratio of the
times, so that the spaces passed over increase in the square of the
times.
The following is a more simple but less accurate rule. Multiply 1142 by
5, which gives 5710; then multiply also 16 by 5, which gives 80, to
which add 1142, this gives 1222, by which sum divide the first product
5710, and the quotient 4.68 will be the time of descent, nearly the
same as before. This taken from 5, leaves 0.32 for the time of the
ascent; which, multiplied by 1142, gives 365 for the depth, differing
but little from the former more exact number.
Note 5, p. 38.--HYDROMANCY.
This superstition still prevails in many parts of England, especially
in Cornwall, where the peasants on certain days of the year assemble at
the springs, or holy wells, and, in the manner stated in the text,
proceed to settle such doubts and enquiries as will not let the idle
and anxious rest. Here, therefore, they come, and, instead of allaying,
deservedly feed their uneasiness; the supposed responses serving
equally to increase the gloom of the low-spirited, the suspicions of
the jealous, and the passion of the enamoured. The superstition,
however, is sanctioned by the highest antiquity. The Castalian
fountain, and many others among the Grecians, were supposed to be of a
prophetic nature. By dipping a fair mirror into a well, the Patræans of
Greece received, as they supposed, some notice of ensuing sickness or
health from the various figures portrayed upon the surface. In Laconia
they cast into a pool, sacred to Juno, cakes of bread-corn; if they
sank, good was portended; if they swam, something dreadful was to
ensue. Sometimes they threw three stones into the water, and formed
their conclusions from the several turns they made in sinking. “From
the several waves and eddies which the sea, river, or other water
exhibited,” says Dr. Borlase, “when put into agitation after a ritual
manner, the ancients pretended to foretell with great certainty the
event of battles; a way of divining recorded by Plutarch in his life of
Cæsar, and still usual among the vulgar in Cornwall; who go to some
noted well, at particular times of the year, and there observe the
bubbles that rise, and the aptness of the water to be troubled, or to
remain pure, on their throwing in pins or pebbles, and thence
conjecture what shall or shall not befall them. The Druids also, as we
have great reason to think, pretended to predict future events, not
only from holy wells and running streams, but from the rain and snow
water, which, when settled, and afterwards stirred, either by oak-leaf
or branch, or magic wand, might exhibit appearances of great
information to the quick-sighted Druid, or seem so to do to the
credulous enquirer, when the priest was at full liberty to represent
the appearances as he thought most for his purpose.”--BORLASE’S
_Antiquities of Cornwall_, p. 140.
In the islands of Scilly there is, or was some years since, a custom of
propitiating fortune by certain ceremonies of this kind. An old
islander regretted to a friend of the author the want of care with
which such ceremonies had of late been conducted, and observed, as the
consequence, that “_they had no luck at all in the islands; not a wreck
had taken place for many months_.”
Note 6, p. 42.--COINS AND MEDALS.
The Latin word _moneta_, for money, is probably more modern than
_pecunia_, and is said to be derived from _moneo_, to advise or mark,
that is, to show by some mark the weight and fineness of the metal of
which coins were composed. Thus, according to Isidorus, “Moneta ita
appellatur, quia monet nè qua fraus in pondere vel metallo fiat.” The
origin of money seems to have been coeval with the first regulations of
civil society, or, at least, it is too remote to be traced by any
authentic history. Barter, that is the exchange of one commodity for
another, was the ordinary mode of traffic in the earlier periods of the
world; a practice which must soon have been discovered extremely
inconvenient, and inadequate to the purposes of commerce; and hence the
invention of a common measure, or standard, according to which all
other things should be estimated. Writers very generally agree in
believing that the metals were first used for such a purpose, as being
almost the only substances whose goodness, and as it were integrity,
were not injured by partition; and which admitted of being melted, and
returned again into a mass of any size or weight. At first, it is
probable that each person cut his metal into pieces of different sizes
and forms, according to the quantity to be given for any merchandize,
or according to the demand of the seller, or the quantity stipulated
between them; to this end they went to market, laden with metal, in
proportion to the purchase to be made, and furnished with instruments
for apportioning it, and with scales for dealing it out, according as
occasion required. By degrees it must have been found commodious to
have pieces ready weighed; and Mr. Pinkerton observes, that such were
prepared without any stated form or impression, but merely regulated to
a certain weight; for _weight_ was the grand standard of ancient
coinage, so that all large sums were paid in weight, even down to the
Saxon period of England. As in Greece the first estimation of money was
merely by weight, so was it in Rome. Silver was the metal first used in
Grecian coinage, but copper in the Roman; the former metal having been
long known to the Romans. The first valuation of Roman money was by the
_libra gravis æris_, or pound of heavy brass: and when by the progress
of their conquests they obtained silver and gold, these were regulated
in the same manner. Let us proceed one step farther in the history of
coins; it is easy to imagine that the growing commerce of money being
disturbed with frauds, both in the weight and the material, the
interposition of public authority became necessary, and that hence
arose the first stamps or impressions of money; to which succeeded the
names of the moneyers, and at length the effigy of the prince, the
date, legend, and other precautions to prevent the alteration of the
species; and thus were coins completed. Gold and silver, in their pure
or unmixed state, are too flexible to make coins sufficiently firm for
general use; and hence the necessity of mixing with them a certain
proportion of some harder metal, and this mixture is called the
_alloy_. The quality of this alloy has been always considered of great
importance with respect to the durability of coins. The most common
metal used for this purpose is copper; and sometimes, for gold, a
mixture of silver and copper. In all well-regulated governments, there
has been a standard fixed by law; that is, a certain proportion between
the quantity of pure metal and its alloy. In England the standard for
gold is 11/12, that is eleven parts of pure metal, and one part of
alloy. The standard for silver is 37/40, a proportion which is said to
have been fixed in the reign of Richard I. by certain persons from the
eastern parts of Germany, called _Easterlings_; and hence the word
_Sterling_, which was afterwards the name given to the silver penny,
and which is now applied to all lawful money of Great Britain.
_Penny_ is derived by Camden from _pecunia_, but others suppose that
the word is formed from _pendo_ to weigh, and the word has been
sometimes written, according to this origin, _pending_. The ancient
English penny, or penig, or pening, was the first silver coin struck in
England, and the only one current amongst our Saxon ancestors. Until
the time of Edward I. the penny was struck with a cross so deeply
indented in it that it might be easily broken, and parted into two
pieces, thence called _half-pennies_, or into four, called
_four-things_, or _farthings_; but that prince coined it without
indenture; in lieu of which he first struck round half-pence and
farthings.
By the term MEDAL, we understand a piece of metal, in the form of a
coin, destined to preserve to posterity the portrait of some great man,
or the memory of some illustrious action. They are distinguished by
their different sizes; those of the larger size, or volume, are called
_medallions_. _Medallets_ is a name given by Pinkerton to those small
pieces, or _missilia_, scattered among the people on solemn occasions;
those struck for the slaves in the Saturnalia, private counters for
gaming, tickets for baths and feasts, tokens in copper and lead, and
the like. Medallions were certainly never intended to become current
coin, as some medals probably were; they were struck purely to serve as
public monuments, or to be presented by the emperor to his friends, and
by the mint-makers to the emperor, as specimens of fine workmanship.
They were struck upon the commencement of the reign of a new emperor,
and other solemn occasions; and frequently, especially the Greek
medallions, as monuments of gratitude, or of flattery. Sometimes they
were trial or pattern pieces, _testimonia probatæ monetæ_; and such
abound after the reign of Maximilian, with the “Tres monetæ” on the
reverse. It is observed, that all the Roman pieces in gold, exceeding
the _denarius aureus_; all in silver, superior to the _denarius_; and
all in brass, superior to the _sestertius_, or what the medallist terms
large brass, are comprehended under the description of medallions. Mr.
Pinkerton, however, thinks that the gold medallions, weighing two,
three, or four aurei only, passed in currency according to their size.
Medallions from the time of Julius to that of Adrian, are very
uncommon, and of very high price; from Adrian to the close of the
western empire they are, generally speaking, less rare. The types of
the Roman medallions are often repeated upon common coin; hence they
appear of less importance than the Greek; impressions of which are
frequently most uncommon, and nowhere else to be found. Many Roman
medallions have S.C., as being struck by order of the senate; those
without these initials, were struck by order of the emperor. Of
Augustus, a noble medallion was found in Herculaneum. There are
medallions of Augustus and Tiberius, struck in Spain; and one of Livia,
at Patræ in Achaia. One in brass, of Antony and Cleopatra; reverse, two
figures in a car, drawn by sea-horses. Of Tiberius there are many; and
also of Claudius, Agrippina, Nero, Galba, Vespasian, and Domitian, &c.
The Greek medallions of Roman emperors are far more numerous than the
Roman; with a few exceptions, however, all medallions are rare and of
princely purchase. Even in the richest cabinet, twenty or thirty
specimens are esteemed a respectable proportion.
The parts of a medal are the two sides, one whereof is called the
_face_, _head_, or obverse; the other the _reverse_. On each side is
the _area_, or _field_; the _rim_, or _border_; and the _exergum_,
which is beneath the ground, whereon the figures represented are
placed. On the two sides are distinguished the _type_, and the
_inscription_, or _legend_. The type, or device, is the figure
represented; the legend is the writing, especially that around the
medal; though in the Greek medals the inscription is frequently on the
area. What we find in the exergum is, generally, no more than some
initial letters, whose meaning we are usually unacquainted with;
though, sometimes, they contain words that may be accounted an
inscription.
The exergum sometimes contains the date of the coin, expressing in what
consulship of the emperor it was struck, as Cos. III. upon the reverse
of an Antoninus. Sometimes it signifies the place where it was struck,
and to which the coin properly belonged, as S. M. AL. for _Signata
Moneta Alexandriœ_, upon the reverse of a Licinius. Sometimes the name
of a province, the reduction of which the medal is designed to
celebrate; as Judæa on the reverse of a Vespasian. Medals usually have
their figures in higher relief than coins.
We have stated that medals are of great importance to the study of
history. They, indeed, furnish the principal proof of historic truth,
as their evidence reaches to the most remote ages, as well as to the
most remote countries. Vaillant, in his learned history of the Syrian
kings, printed at Paris, 1681, first fixed the dates, and arranged the
order of events in ancient historians, by means of these infallible
vouchers. Thus he was enabled to ascertain the chronology and progress
of events of three of the most important kingdoms of the ancient world;
viz. those of Egypt, of Syria, and of Parthia. The study of the Roman
medals has, in this respect, an advantage over that of Greek coins,
since they serve not only to illustrate the chronology of reigns, but
to aid us in the interpretation of particular events. To this purpose,
besides the portrait of the prince, and date of his consulship, or of
his tribunitian power, we have a representation, or poetical symbol, of
some grand event on the reverse. In a word, the series of Roman coins
presents the very best suite of documents relating to the Roman
History. In addition to its historical importance, the medal is
frequently a useful guide to geography, natural history, architecture,
ancient monuments, busts, statues, ceremonies, and the like. See
Addison’s _Dialogues on the Usefulness of Ancient Medals_. On this
subject, also, Pinkerton, in his valuable work on medals, has some
interesting remarks; he says that, to a man of poetical imagination,
the Roman coins must prove an ample source of intellectual delight, by
means of the fine personifications and symbols which are to be found on
their reverse. _Happiness_ has sometimes the caduceus, or wand of
Mercury, which Cicero tells us was thought to procure the gratification
of every wish. In a gold coin of Severus, she has heads of poppy to
express that our prime bliss lies in oblivion of misfortune. _Hope_ is
represented as a sprightly damsel, walking quickly and looking
straightforward. With her left hand she holds up her garments, that
they may not hinder the rapidity of her pace; while, in her right hand,
she holds forth the bud of a flower, an emblem infinitely more
beautiful than the trite one of an anchor, which is the symbol of
Patience, not of Hope. _Abundance_ is imaged as a sedate matron, with a
cornucopiæ in her hands, of which she scatters the fruits over the
ground: but does not hold it up, and keep its contents to herself, as
many poets and painters have represented her. _Security_ stands leaning
on a pillar, indicative of her being free from all designs and
pursuits; and the posture itself corresponds to her name.
Coins also present us with countries and rivers admirably personified.
On the reverse of a colonial coin, rude in execution, of Augustus and
Agrippa, inscribed IMP. and DIVI. F., the conquest of Egypt is
represented by the apposite metaphor of the crocodile, an animal almost
peculiar to that country, and at that period esteemed altogether so,
which is chained to a palm tree, at once a native of the country, and
symbolic of victory. Moreover, a cabinet of medals, of which Rubens is
said to have possessed a very magnificent one, may be considered as
forming the classic erudition of a painter. We may add, that almost all
the uses which connect the science of medals with painting, render it
also subservient to the art of the sculptor, who cannot less than
profit by the study of the Greek coins in particular. The connexion of
the study of ancient coins with architecture, consists in the views of
many of the ancient edifices, which are found in perfect preservation
on medals. Froelich observes, that the coins of Tarsus are very
remarkable for a kind of perspective in the figures. On others are
found triumphal arches, temples, fountains, aqueducts, amphitheatres,
circuses, palaces, columns, obelisks, baths, sea-ports, pharoses, and
the like.
The study of medals affords such a variety of amusement and of
instruction, that we may naturally suppose it to be nearly as ancient
as medals themselves; and yet ancient writers do not furnish us with a
single hint of collections of this kind. In the days of Greece, a
collection of such coins as then existed would not be regarded as an
acquisition of any great value, because it must have consisted only of
those that were struck by the innumerable little states which then used
the Greek characters and language, and of course it would be considered
as a kind of domestic coinage, precluded from extension by the narrow
limits of the intercourse that subsisted between different provinces
and countries. As soon as any communication was opened between the
Romans and the Greeks, the Grecian coins were imitated by the Roman
workmen, and preserved in the cabinets of their senators among the
choicest treasures. In a more advanced period of the Roman empire,
individuals must have formed collections of Roman coins; for we find
that a complete series of silver was lately found in our island,
containing inclusively all the emperors down to Carausius. From the
decline of the Roman empire, most branches of science were enveloped in
darkness, till the revival of letters towards the end of the fifteenth
century. When literature began to be cultivated in Italy, the study of
medals, connected with that of ancient erudition, began to engage
attention. Accordingly Petrarch, who in modern times was amongst the
first persons in Europe that aspired to the celebrity of learning and
genius, was likewise the first to revive the study of medals. This
eminent man, having been desired by the Emperor Charles V. to compose a
book that should contain a history of the coins of illustrious men, and
to place him in the list, is said to have returned for answer, that he
would comply with his desire, whenever the Emperor’s future life and
actions deserved it. Availing himself of this circumstance, he sent
that monarch a collection of gold and silver coins of celebrated men.
“Behold!” said he, “to what men you have succeeded! Behold whom you
should imitate and admire! to whose very form and image you should
compose your talents! The invaluable present I should have given to no
one but yourself; it was due to you alone. I can only know or describe
the deeds of these great men: your supreme office enables you to
imitate them.” In the next age, Alphonso, king of Arragon, caused all
the ancient coins that could be discovered throughout the provinces of
Italy to be collected, which he placed in an ivory cabinet, and always
carried about with him, that he might be excited to great actions by
the presence, as it were, of so many illustrious men in their images.
To those who are desirous of gaining information upon this interesting
branch of antiquarian research, we strongly recommend Mr. Pinkerton’s
_Essay on Medals_.
Having been led to offer these observations on ancient medals, we may,
perhaps, be allowed to make one other digression on a subject naturally
suggested by a visit to the vicarage of our reverend antiquary. The
reader has been told, that “around his house he had arranged several
precious relics, amongst which was an ancient cross, raised upon a
platform on three steps.”
There is much obscurity with regard to the origin and uses of these
stone crosses. We are, however, not disposed to enter into a discussion
of such difficulty; but the reader may be gratified in having presented
to him, in one view, a collection of such crosses as still exist in
various parts of Cornwall.
[Illustration: Two types of stone crosses.]
[Illustration: Four more types of stone crosses.]
Note 7, p. 49.--BODIES REVOLVE ON THE SHORTER AXIS.
Upon this subject, the reader is requested to turn to page 138, where
it is stated that a body will permanently rotate only on its shortest
axis. The philosophy of the fact is simply this--while a body revolves
on its axis, the component particles of its mass move in circles, the
centres of which are placed in the axis; a centrifugal force therefore
is generated, which is resisted by the cohesion of the parts of the
mass, and this tendency of each particle to fly off is expended in
exciting a pressure upon the axis; and it is this strain which produces
the effect in question, the axis of no pressure being alone the
permanent axis.
VIS INERTIÆ, p. 59.--The criticism of the vicar upon this subject is
scientifically judicious; but the literary reader who has justly
appreciated his character, may be inclined to ask how it could have
happened that he should have overlooked the classical authority by
which the expression is countenanced; we cannot answer the question,
but we will supply the deficiency. The connecting two ideas, which at
first sight appear opposed to each other, constituted a figure of
speech much used both by the Greeks and Romans. Euripides delighted in
it, which was a sufficient reason for Aristophanes to satirise it.
Horace has given us several examples of it, as “_Insaniens
sapientia_”--“_Strenua inertia_.”
Note 8, p. 62.--THE MECHANICAL POWERS.
Mechanical powers are simple arrangements by which we gain power at the
expense of time; thus, if a certain weight can be raised to a certain
height by unassisted strength, and the same thing is afterwards done
with one tenth part of the exertion, through the use of a mechanic
power, it will be found to occupy ten times as much time. In many
cases, however, loss of time is not to be put in competition with the
ability to do a thing; and since the advantages which the mechanical
powers afford to man, by enabling him to perform feats which, without
their assistance, would have been for ever beyond his reach, are
incalculably great, the waste of time is overlooked, and is much more
than balanced in the general result. It is true, that if there are
several small weights, manageable by human strength, to be raised to a
certain height, it may be full as convenient to elevate them one by
one, as to take the advantage of the mechanical powers in raising them
all at once; because the same time will be necessary in both cases: but
suppose we should have an enormous block of stone, or a great tree, to
raise; bodies of this description cannot be separated into parts
proportionable to the human strength without immense labour, nor,
perhaps, without rendering them unfit for those purposes to which they
are to be applied; hence then the great importance of the mechanical
powers, by the use of which a man is able to manage with ease a weight
many times greater than himself.
To understand the principle of a mechanical power, we must revert to
the doctrine of momentum. It will be remembered, that a small ball,
weighing only two pounds, and moving at the rate of 500 feet in a
second, will produce as much effect as a cannon ball of ten pounds in
weight, provided it only moved at the rate of 100 feet in the same
time; in like manner a ball weighing one pound may be made to balance
another of five pounds, by placing it five times farther from the
centre of motion; for in such a case, for every inch of space through
which the large ball passes, the small one will traverse five inches,
and will thus generate five times the momentum. This may be rendered
still more evident by turning to page 161, and note thereon, where the
_see-saw_ is described, which, in fact, is a true mechanical power. It
will be at once evident, from an inspection of the figure, that the
lesser boy will pass over a much greater space, in equal time, than the
greater boy, and thus generate more momentum, which compensates for his
defect in weight, and renders him a balance for his heavier
companion.--_See note 23._
Note 9, p. 76.--CENTRE OF GRAVITY.
Those who have been in the habit of inspecting the works of the
statuary, must frequently have detected the art which he has displayed
in imparting stability to his figures, by lowering their centre of
gravity. The bronze figure of Achilles, in Hyde Park, affords a very
striking illustration of such ingenuity; it is evident, from the
position and height of the figure, that, had not a mass of matter been
added to its base, its stability would have been extremely precarious,
since the slightest movement might have thrown its line of direction
beyond the base; but the addition at the base renders such an accident
impossible, by lowering its centre of gravity. Other examples of
similar contrivance are presented in several celebrated statues,
wherein stability is ensured by the judicious distribution of the
draperies. In the celebrated statue of Peter at St. Petersburgh, the
equilibrium of the mass is thus sustained by the introduction of a
serpent twining upwards to his horse’s tail. The effect, however, is so
unfortunate as to have given occasion for a wit to remark, “It is a
very fine horse, but what a pity that he should have worms!” Nor have
our celebrated painters overlooked a principle, the neglect of which
would have withheld from the most symmetrical figures the charms of
beautiful proportion.
Note 10, p. 93.--THE INDIAN BLOW-PIPE.
“When a native of Macoushi goes in quest of feathered game, or other
birds, he seldom carries his bow and arrows. It is the _blow-pipe_ he
then uses. This extraordinary tube of death is, perhaps, one of the
greatest natural curiosities in Guiana. It is not found in the country
of Macoushi. Those Indians tell you that it grows to the south-west of
them, in the wilds which extend betwixt them and the Rio Negro. The
reed must grow to an amazing length, as the part the Indians use is
from ten to eleven feet long, and no tapering can be perceived in it,
one end being as thick as the other. It is of a bright yellow colour,
perfectly smooth both inside and out. It grows hollow; nor is there the
least appearance of a knot or joint throughout the whole extent. The
natives call it _ourah_. This, of itself, is too slender to answer the
end of a blow-pipe; but there is a species of palma, larger and
stronger, and common in Guiana, and this the Indians make use of as a
case, in which they put the _ourah_. It is brown, susceptible of a fine
polish, and appears as if it had joints five or six inches from each
other. It is called _samourah_, and the pulp inside is easily
extracted, by steeping it for a few days in water. Thus the ourah and
samourah, one within the other, form the blow-pipe of Guiana. The end
which is applied to the mouth is tied round with a small silk-grass
cord, to prevent its splitting; and the other end, which is apt to
strike against the ground, is secured by the seed of the acuero fruit,
cut horizontally through the middle, with a hole made in the end,
through which is put the extremity of the blow-pipe. It is fastened on
with string on the outside, and the inside is filled up with wild
bees-wax. The arrow is from nine to ten inches long. It is made out of
the leaf of a species of palm-tree, called _coucourite_, hard and
brittle, and pointed as sharp as a needle. About an inch of the pointed
end is poisoned with the _wourali_. The other end is burnt, to make it
still harder, and wild cotton is put round it for about an inch and a
half. It requires considerable practice to put on this cotton well. It
must just be large enough to fit the hollow of the tube, and taper off
to nothing downwards. They tie it on with a thread of the silk-grass to
prevent its slipping off the arrow.”
“The Indians have shown ingenuity in making a quiver to hold the
arrows. It will contain from five to six hundred...
“...With a quiver of poisoned arrows slung over his shoulder, and with
his blow-pipe in his hand, in the same position as a soldier carries
his musket, see the Macoushi Indian advancing towards the forest in
quest of powises, maroudis, waracabas, and other feathered game.
“These generally sit high up in the tall and tufted trees, but still
are not out of the Indian’s reach; for this blow-pipe, at its greatest
elevation, will send an arrow 300 feet. Silent as midnight he steals
under them, and so cautiously does he tread the ground, that the fallen
leaves rustle not beneath his feet. His ears are open to the least
sound, while his eye, keen as that of the lynx, is employed in finding
out the game in the thickest shade. Often he imitates their cry, and
decoys them from tree to tree, till they are within range of his tube.
Then, taking a poisoned arrow from his quiver, he puts it in the
blow-pipe, and collects his breath for the fatal puff. About two feet
from the end through which he blows, there are fastened two teeth of
the acouri, and these serve him for a sight. Silent and swift the arrow
flies, and seldom fails to pierce the object at which it is sent.
Sometimes the wounded bird remains in the same tree where it was shot,
and in three minutes falls down at the Indian’s feet. Should he take
wing, his flight is of short duration; and the Indian, following the
direction he has gone, is sure to find him dead. It is natural to
imagine that, when a slight wound only is inflicted, the game will make
its escape. Far otherwise; the wourali poison almost instantaneously
mixes with blood or water, so that if you wet your finger, and dash it
along the poisoned arrow in the quickest manner possible, you are sure
to carry off some of the poison. Though three minutes generally elapse
before the convulsions come on in the wounded bird, still a stupor
evidently takes place sooner, and this stupor manifests itself by an
apparent unwillingness in the bird to move.” ...
“The Indian, on his return home, carefully suspends his blow-pipe from
the top of his spiral roof; seldom placing it in an oblique position,
lest it should receive a cast.”--WATERTON’S _Wanderings in South
America_, p. 58.
Note 11, p. 96.--PENDULUM AND SPRING.
A clock is nothing more than a piece of machinery to maintain the
action of the pendulum, and at the same time to count and register the
number of its oscillations; and by that peculiar property, that one
vibration commences exactly where the last terminates, no part of time
is lost or gained in the juxtaposition of the units so counted.
If some extraneous force were not applied, in a clock or watch, to
maintain or perpetuate the natural vibrations of a pendulum, or
oscillations of a balance, they would soon come to rest, by reason of
friction in the mechanism, and the resistance opposed by the air to the
parts in motion. This force, in the larger clocks, is usually a
suspended weight; but, in the portable clock and watch, it is a spring
coiled in a metallic box, that actuates the wheel-work by gradually
unbending itself.
In the former of these cases, the weight is suspended by a cord or
chain that is coiled round a cylinder when wound up, which cylinder
being of uniform diameter throughout its length, is acted on by the
cord, when fast at the interior end, by a similar force in every
situation; and, therefore, imparts through the train, connected with
its great wheel, invariable impulses to the escapement-wheel, at every
vibration of the pendulum; which pendulum receives therefrom such a
slight push, as is just sufficient to restore the momentum which it
loses from friction and the air’s resistance, and thus the uniform
motion of the pendulum is perpetuated. But when a spring is substituted
for a weight, it is clear that its agency cannot be uniform, since, as
the reader will learn by turning to page 101, it is a general law that
elastic bodies, in the recovery of their form, after the removal of the
compressing force, exert a greater power at first than at last, so that
the whole progress of restoration is a _retarded_ motion. It,
therefore, became necessary to introduce some mechanical contrivance
which might equalize such motion. This correction is effected by an
apparatus termed a FUSEE, and is nothing more than the application of
the wheel and axle; it is that conical barrel seen in most watches
round which the chain coils in the act of winding up. When the fusee is
full of chain, or the watch is wound up, the spring, through the medium
of the chain, will act upon its upper part, which being very near the
centre will give the spring but little power; but, as the spring
uncoils and diminishes in strength, it will act upon a larger part of
the fusee, until at last it gets to the bottom of it, and consequently,
if the several increasing grooves upon it are made to increase in the
same proportion as the power of the spring decreases, an equable force
must be obtained.
Springs may be thus said to afford the means of _packing up_ force, to
be used whenever it is required. Mr. Babbage observes that the half
minute which we daily devote to the winding up our watches is an
exertion by which we _pack_ a quantity of force, which is gradually
expended during the ensuing twenty-four hours. Springs then will enable
us to avail ourselves of inconstant and variable forces which must
otherwise remain incapable of useful application, and the period may
arrive when force will thus become an article of traffic, and machines
be sent to the windmill to be wound up. The manner in which force is
constantly allowed to run to waste is quite extraordinary in the
present advanced state of science. We need only look at the working of
the treadmill. The public are little aware of the enormous sums
annually expended in towing vessels by steam from the Nore to the port
of London; were floating treadmills established, the labour of those,
upon whom punishment has been awarded, might be rendered available to
the most important interests; whereas, with the present system, not
only is this labour entirely lost, but is actually a source of expense,
for machines, with all the accompaniments of engineers, are provided to
counterbalance the force so uselessly generated.
Note 12, p. 97.--ELASTIC CHAIRS AND BEDS.
The elastic property of iron springs has been lately exemplified in a
very striking manner, by the invention of Pratt’s elastic chairs and
beds; which, instead of the usual stuffing of feathers, are filled with
iron wire!!! which is twisted into spiral form. Down itself cannot be
more gentle or springy; it yields to pressure, and yet never becomes
lumpy: beds thus constructed have the advantage of not heating the
body; and, above all, they never require to be shaken or “made.” Had
Vulcan fortunately made such a discovery before his ejectment from
Olympus, his wife, Venus, would surely never have treated him with that
contempt which mythologists have recorded of her; while her
priestesses, the housemaids, must, in gratitude, have been bound to
extend their protection to a benefactor, who could save them so much
daily labour. For particulars of this curious invention, the reader may
consult the _Literary Gazette_ for March 17, 1827.
Note 13, p. 98.--DUCK AND DRAKE.
The phenomenon has been explained as depending upon the inertia of the
parts of matter, which renders a certain time necessary in order to
communicate to any body a sensible motion; so that when a body, moving
with considerable velocity, meets with another of much greater size, it
experiences almost as much resistance as if the latter were fixed.
Nothing is easier to be divided than water; yet, if the palm of the
hand be struck with some velocity against its surface, a considerable
degree of resistance, and even of pain, is experienced from it, as if a
solid body had been struck; nay, a musket ball, when fired against
water, is repelled and even flattened by it. In like manner, if we load
a musket with powder, and, instead of a ball, introduce a candle, and
fire it against a board, the latter will be pierced by the candle end,
as if by a ball. The cause of this phenomenon, no doubt, is, that the
rapid motion with which the candle end is impelled, does not allow it
time to be flattened, and therefore it acts as a hard body.
Note 14, p. 99.--VEGETABLE ELASTICITY.
_Impatiens_, or _Touch me not_, affords a good example. The seed-vessel
consists of one cell with five divisions; each of these, when the seed
is ripe, on being touched, suddenly folds itself into a spiral form,
leaps from the stalk, and disperses the seeds to a great distance by
its elasticity. The capsule of the geranium and the beard of wild oats
are twisted for a similar purpose. (DARWIN’S _Botanic Garden_.) The
seed-vessel of Euphorbia is extremely elastic, projecting the seeds
with great force. An elastic pouch also serves to scatter the seeds of
the Oxalis.
Note 15, p. 125.--A SIMPLE ORRERY.
A very instructive toy might be constructed by placing a taper in the
centre of a japanned waiter, to represent the sun, and fixing in a
watch glass an indian rubber ball, with the parallels of latitude and
meridians painted thereon, with the other characters of the globe.
During its revolution around the candle, in consequence of the tendency
of its centre of gravity to its lowest position, the diurnal and annual
motions, and also the parallelism of its axis, will be represented,
together with the concomitant phenomena.
Note 16, p. 130.--CONIC SECTIONS.
If a cone, or sugar-loaf, be cut through in certain directions, we
shall obtain figures which are termed _conic sections_; thus, if we cut
through the sugar-loaf in a direction parallel to its base, or bottom,
the outline or edge of the loaf where it is cut will be a _circle_. If
the cut is made so as to slant, and not be parallel to the base of the
loaf, the outline is an _ellipse_, provided the cut goes quite through
the sides of the loaf all round; but if it goes slanting, and parallel
to the line of the loaf’s side, the outline is a _parabola_, a conic
section, or curve, to which this note more immediately relates. This
curve is distinguished by characteristic properties, every point of it
bearing a certain fixed relation to a certain point within it, as the
circle does to its centre.
Note 17, p. 134.--EARTHQUAKE OF LISBON.
During the dreadful earthquake of Lisbon, bands of wretches took
advantage of the general consternation to commit the most atrocious
acts of robbery and murder. In fact, a considerable part of the city
was destroyed by incendiaries, who, during the disaster, set fire to
the houses, that they might pillage them with greater impunity.
Note 18, p. 134.--GEOLOGY APPLIED TO AGRICULTURE.
Soils consist of a mixture of different finely divided earthy matter,
with animal or vegetable substances in a state of decomposition. In
order, therefore, to form a just idea of their nature, it is necessary
to conceive different rocks decomposed, or ground into parts and powder
of different degrees of fineness; some of their soluble parts dissolved
by water, and that water adhering to the mass, and the whole mixed with
larger or smaller quantities of the remains of vegetables and animals,
in different stages of decay. Hence it will follow, that certain rocks
will give origin to particular soils; thus poor and hungry soils, such
as are produced from the decomposition of granite and sandstone, remain
very often for ages with only a thin covering of vegetation; while
soils from the decomposition of limestone, chalk, and basalt, are often
clothed by nature with the perennial grasses; and afford, when ploughed
up, a rich bed of vegetation for every species of cultivated plant. In
adverting to this subject, Dr. Buckland, in his inaugural lecture, very
justly observes, that it furnishes an instance of relation between the
vegetable and mineral kingdoms, and of the adaptation of one to the
other, which always implies design in the surest manner; for had not
the surface of the earth been thus prepared for their reception, where
would have been the use of all that admirable system of organization
bestowed upon vegetables? And it is no small proof of design in the
arrangement of the materials that compose the surface of our earth,
that whereas the primitive and granitic rocks are least calculated to
afford a fertile soil, they are for the most part made to constitute
the mountain districts of the world, which, from their elevation and
irregularities, would otherwise be but ill adapted for human
habitation; whilst the lower and more temperate regions are usually
composed of derivative or secondary strata, in which the compound
nature of their ingredients qualifies them to be of the greatest
utility to mankind by their subserviency to the purposes of luxuriant
vegetation.
No doubt, then, can exist as to the important connexion between the
geological structure of a country, and its degree of fertility; but the
subject has not received the attention which it merits. And in the hope
that this note may meet the eye of some zealous geologist, the author
suggests the importance of commencing the enquiry in a primitive
district; for, as we advance from a primitive to an alluvial district,
the relations to which we have alluded become gradually less distinct
and apparent, and are ultimately lost in the confused complication of
the soil itself, and in that general obscurity which necessarily
envelopes every object in a state of decomposition: we can, therefore,
only hope to succeed in such an investigation, by a patient and
laborious examination of a primitive country, after which we may be
enabled to extend our enquiries with advantage through those districts
which are more completely covered with soil, and obscured by luxuriant
vegetation; as the eye, gazing upon a beautiful statue, traces the
outline of the limbs, and the swelling contour of its form, through the
flowing draperies which invest it.
Note 19, p. 135.--BUCKLAND’S RESEARCHES.
The geological researches of Dr. Buckland have been long directed by a
desire to accumulate facts to prove that there must have been an
universal inundation of the earth; and, in his inaugural lecture, he
has presented us with a summary of such facts, which, to use his own
expression, whether considered collectively or separately, present such
a conformity of proofs, tending to establish the universality of a
recent inundation of the earth, as no difficulties or objections that
have hitherto arisen are in any way sufficient to overrule.
In the year 1822, Dr. Buckland read a memoir before the Royal Society,
announcing the discovery of a singular cave at Kirkdale in Yorkshire,
containing an assemblage of fossil teeth and bones of the elephant,
rhinoceros, hippopotamus, bear, tiger, and hyæna, and sixteen other
animals; with a comparative view of five similar caverns in various
parts of England, and others on the continent. For this important paper
the society awarded to its author their Copley medal; and it
constitutes the basis of a later and much more extended work, entitled
“RELIQUIÆ DILUVIANÆ; or Observations on the Organic Remains contained
in Caves, Fissures, and Diluvial Gravel; and on other Geological
Phenomena, attesting the Action of an Universal Deluge. By the Rev. W.
BUCKLAND, B.D. F.R.S. &c.”
Let us explore the interior of this cavern. It was not till the summer
of 1821, that the existence of any animal remains, or of the cavern
containing them, was suspected. At this time, in continuing the
operations of a large quarry, the workmen accidentally intersected the
mouth of a long hole, closed externally with rubbish, and overgrown
with grass and bushes. As this rubbish was removed before any competent
person had examined it, it is not certain whether it was composed of
diluvial gravel and rolled pebbles, or was simply the debris that had
fallen from the softer portions of the strata that lay above it: the
workman, however, who removed it, and some gentlemen who saw it,
assured Dr. Buckland that it was composed of gravel and sand. In the
interior of the cavern, our indefatigable geologist could not find a
single rolled pebble, nor has he ever seen one bone, or fragment of
bone, that bore the slightest mark of having been rolled by the action
of water.
The original entrance is said to have been very small, and, having been
filled up as above described, there could not have been any admission
of external air through it to the interior of the cavern. Nearly 30
feet of its outer extremity have now been removed, and the present
entrance is a hole in the perpendicular face of the quarry, about three
feet high and five feet broad, which it is only possible for a man to
enter on his hands and knees, and which expands and contracts itself
irregularly from two to seven feet in breadth, and two to fourteen feet
in height. It is unnecessary to enter into farther details; the reader,
if he wishes more minute information, may consult Dr. Buckland’s work.
On entering the cave, the first thing observed was a sediment of soft
mud or loam, covering entirely its whole bottom to the average depth of
about a foot, and concealing the subjacent rock, or actual floor of the
cavern. Not a particle of mud was found attached either to the sides or
roof; nor was there a trace of it adhering to the sides or upper
portions of the transverse fissures, or any thing to suggest the idea
that it had entered through them. The mud was covered by a
_stalagmitic_ crust, which had been formed by the dripping of water
impregnated with calcareous matter, as is common in all the cavities of
limestone; but it is important to remark, that there was not any
alternation of mud with any repeated beds of _stalagmite_, but simply a
partial deposit of the latter on the floor beneath; so that the mud was
encased, like meat in a pie, with an upper and under crust. It was
chiefly in the lower part of the earthy sediment, and in the calcareous
matter beneath it, that the animal remains were found.
In the whole extent of the cave, only a very few large bones have been
discovered that are tolerably perfect; most of them are broken into
small angular fragments and chips, the greater part of which lay
separately in the mud, whilst others were wholly or partially invested
with stalagmite, and others again mixed with masses of still smaller
fragments. In some few places, where the mud was shallow, and the heaps
of teeth and bones considerable, parts of the latter were elevated some
inches above the surface of the mud and its calcareous crust; and the
upper ends of the bones thus projecting, like the legs of pigeons
through a pie crust, into the void space above, have become thinly
covered with calcareous drippings, whilst their lower extremities have
no such incrustation, and have simply adhering to them the mud in which
they have been imbedded.
The effect of the loam and stalagmite in preserving the bones from
decomposition, by protecting them from all access of atmospheric air,
has been very remarkable.
The workmen, in first discovering the bones at Kirkdale, supposed them
to have belonged to cattle that died by a murrain in this district a
few years ago, and they were for some time neglected, and thrown on the
roads with the common limestone; they were, at length, noticed by Mr.
Harrison, a medical gentleman in the neighbourhood, and have since been
collected and deposited in various private and public museums. The
teeth and bones which have been discovered in this cave appear to have
belonged to the _hyæna, tiger, bear, wolf, fox, weasel, elephant,
rhinoceros, hippopotamus, horse, ox, deer, hare, rabbit, water-rat,
mouse, raven, pigeon, lark, snipe_, and a small species of _duck_.
The bottom of the cave, on first removing the mud, was found to be
strewed all over like a dog-kennel, from one end to the other, with
hundreds of teeth and bones, or rather broken and splintered fragments
of bones, of all the animals above enumerated; scarcely a single bone
has escaped fracture, with the exception of some of the more solid and
hard bones of the foot; on some of these bones marks may be traced,
which, on applying one to the other, appear exactly to fit the form of
the canine teeth of the hyæna that occur in the cave. The hyæna’s bones
have been broken, and apparently gnawed equally with those of the other
animals. Heaps of small splinters, and highly comminuted, yet angular
fragments of bone, mixed with teeth of all the varieties of animals
above enumerated, lay in the bottom of the den, occasionally adhering
together by calcareous cement. Not one skull is to be found entire; and
it is so rare to find a large bone of any kind that has not been more
or less broken, that there is no hope of obtaining materials for the
construction of a single limb, and still less of an entire skeleton.
The jaw-bones, also, even of the hyænas, are broken to pieces like the
rest.
It must already appear probable, from the facts above described,
particularly from the comminuted and gnawed condition of the bones,
that the cave at Kirkdale was, during a long succession of years,
inhabited as a den by hyænas, and that they dragged into its recesses
the other animals, whose remains are found indiscriminately mixed with
their own: an hypothesis which is certainly strengthened by Dr.
Buckland having found the excrement of the animal in the same cave.
Should it be asked why we do not find, at least, the entire skeleton of
the one or more hyænas that died last, and left no survivors to devour
them; we find a sufficient reply to this question, in the circumstance
of the probable destruction of the last individuals by the waters of
the deluge. On the rise of these, had there been any hyænas in the den,
they would have rushed out, and fled for safety to the hills; and if
absent, they could not by any possibility have returned to it from the
higher levels; that they were extirpated by the catastrophe is obvious,
from the discovery of their bones in the diluvial gravel both of
England and Germany.
The accumulation of these bones, then, appears to have been a process
of years, whilst all the animals in question were natives of this
country. The general dispersion of bones of the same animals through
the diluvial gravel of high latitudes, over a great part of the
northern hemisphere, shows that the period in which they inhabited
these regions was that immediately preceding the formation of this
gravel, and that they perished by the same waters which produced it. M.
Cuvier has, moreover, ascertained that the fossil elephant, rhinoceros,
hippopotamus, and hyæna, belong to species now unknown; and as there is
no evidence that they have at any time, subsequent to the formation of
the diluvium, existed in these regions, we may conclude that the period
at which the bones of these extinct species were introduced into the
cave at Kirkdale was before the deluge.
Thus the phenomena of this cave seem referable to a period immediately
antecedent to the general deluge, and in which the world was inhabited
by land animals, almost all bearing a generic, and many a specific
resemblance to those which now exist; but so completely has the
violence of that tremendous convulsion destroyed and remodelled the
form of the antediluvian surface, that it is only in caverns that have
been protected from its ravages, that we may hope to find undisturbed
evidence of events in the period immediately preceding it. The bones
already described, and the calcareous matter formed before the
introduction of the diluvial mud, are what Dr. Buckland considers to be
the products of the period in question. It was indeed probable, before
the discovery of this cave, from the abundance in which the remains of
similar species occur in superficial gravel beds, which cannot be
referred to any other than a diluvial origin, that such animals were
the antediluvian inhabitants not only of this country, but generally of
all those northern latitudes in which their remains are found, (but the
proof was imperfect, as it was possible they might have been drifted or
floated hither by the waters from the warmer regions of the earth,) but
the facts developed in this charnel-house of the antediluvian forests
of Yorkshire demonstrate that there was a long succession of years, in
which the elephant, rhinoceros, and hippopotamus had been the prey of
the hyænas, which, like themselves, inhabited England in the period
immediately preceding the formation of the diluvial gravel. Having thus
far described the principal facts to be observed in the interior of
this cave, Dr. Buckland proceeds to point out the chronological
inferences that may be derived from the state of the bones, and of the
mud and stalagmite that accompany them, and to extract the following
detail of events that have been going on successively within this
curious cave:--
First, There appears to have been a period (and, if we may form an
estimate from the small quantity of stalagmite now found on the actual
floor of the cave, a very short one,) during which this aperture in the
rock existed in its present state, but was not tenanted by the hyænas.
The second period was that during which the cave was inhabited by the
hyænas, and the stalactite and stalagmite were still forming.
The third period is that at which the mud was introduced and the
animals extirpated, viz. the period of the deluge. It has been already
stated, that there is not any alternation of this mud with beds of bone
or of stalagmite, such as would have occurred had it been produced by
land floods often repeated; _once_, _and once only_, it appears to have
been introduced; and we may consider its vehicle to have been the
turbid waters of the same inundation that produced universally the
diluvial gravel.
The fourth period is that during which the stalagmite was deposited
which invests the upper surface of the mud.
In concluding this note, we take the opportunity of recommending all
those who feel interested in the researches of geology, to read a work
lately published, entitled “THE WONDERS OF GEOLOGY, by Gideon Mantell,
LL.D. F.R.S. &c.”
Note 20, p. 137.--THE RIFLE.
Rifle guns are those whose barrels, instead of being smooth on the
inside, like our common pieces, are formed with a number of spiral
channels, resembling screws; except only that the threads, or rifles,
are less deflected, making only one turn, or a little more, in the
whole length of the piece. This construction is employed for correcting
the irregularity in the flight of balls from smooth barrels, by
imparting to the balls a rotatory motion perpendicular to the line of
direction. The same effect has lately been accomplished by an extremely
simple and obvious contrivance, and which will, probably, altogether
supersede the necessity of rifling the barrel. It consists in cutting a
spiral groove in the bullet itself, which, when discharged, is thus
acted upon by the air, and the same rotatory motion imparted to it as
that produced by the furrows in the barrel. But it is the rotatory
motion which steadies the flight of the ball; and by whichever method
this is produced, the theory of its action will be the same. It has
been long and generally known, that when the common bullet is
discharged from a plane barrel, its flight is extremely irregular and
uncertain; it has, for instance, been found, from the experiments of
Mr. Robins, that, notwithstanding the piece was firmly fixed, and fired
with the same weight of powder, the ball was sometimes deflected to the
right, sometimes to the left, sometimes above, and at others below the
true line of direction. It has also been observed, that the degree of
deflection increases in a much greater proportion than the distance of
the object fired at. It is not difficult to account for these
irregularities; they, doubtless, proceed from the impossibility of
fitting a ball so accurately to any plane piece, but that it will rub
more against one side of the barrel than another in its passage through
it. Whatever side, therefore, of the muzzle, the ball is last in
contact with, on quitting the piece, it will acquire a whirling motion
towards that side, and will be found to bend the line of its flight in
the same direction, whether it be upwards or downwards, to the right or
left; or obliquely, partaking in some degree of both; and, after
quitting the barrel, this deflection, though in the first instance but
trifling and inconsiderable, is still farther increased by the
resistance of the air; this being greatest on that side where the
whirling motion conspires with the progressive one, and least on that
side where it is opposed to it. Thus, if the ball, in its passage out,
rubs against the left side of the barrel, it will whirl towards that
side; and as the right side of the ball will, therefore, turn up
against the air during its flight, the resistance of the air will
become greatest on the right side, and the ball be forced away to the
left, which was the direction it whirled in. It happens, moreover, from
various accidental circumstances, that the axis of the ball’s rotation
frequently changes its position several times during the flight; so
that the ball, instead of bending its course uniformly in the same
direction, often describes a track variously contorted. From this view
of the causes of aberration in the flight of balls, it will be evident
that the only means of correcting it is by preventing the ball from
rubbing more against one side of the barrel than another in passing
through it; and by giving to the bullet a motion which will counteract
every accidental one, and preserve its direction, by making the
resistance of the air upon the forepart continue the same during its
whole flight; that is, by giving it a rotatory motion perpendicular to
the line of direction. The contrivance for this purpose is called
_rifling_, and consists, as we have before stated, in forming upon the
inside of the barrel a number of threads and furrows, either in a
straight or spiral direction, into which the ball is moulded; and
hence, when the gun is fired, the indented zone of the bullet follows
the sweep of the rifle, and thereby, besides its progressive motion,
acquires a considerable one round the axis of the barrel, which motion
will be continued to the bullet after its separation from the piece, so
that it is constantly made to whirl round an axis coincident with the
line of its flight. Many familiar examples of the utility and effect of
_rifling_ might be here adduced. If the bricklayer, while unroofing a
house, be observed, he will be seen to give to the slates which he
throws down a whirling motion, at a certain angle, which ensures their
falling edgeways on the ground, and thus preserves them from fracture.
In relation to the subject in the text, to which this note refers, may
be introduced a notice of the “BOMMERENG,” a missile used by the
natives of Australia, and thus described by Major Mitchell in his
“_Journal of an expedition to the Rivers Darling and Murray._” “The
bommereng, a thin, curved missile, about two feet four inches long, can
be thrown by a skilful hand so as to rise upon the wind with a rotatory
motion, and in a crooked direction towards any given point with great
precision, and to return, after a considerable flight, to within a yard
or two of the thrower; or, by striking the ground near him, to bound so
as to hit at a great, distance, “_en ricochet_” any object behind a
tree. This singular weapon probably originated in the utility of such a
missile for the purpose of killing ducks, where they are very numerous,
as on the interior rivers and lagoons, and where we accordingly find it
much more in use than on the sea coast, and better made, being often
covered with good carving.” This instrument may now be purchased in
most of the London toy-shops.
Note 21, p. 144.--CENTRE OF PERCUSSION.
If a stick be held at one of its extremities, and allowed to fall on
the edge of a table, the farther end will rebound, or the hand will
sustain a shock, unless it be struck exactly on the centre of
percussion, in which case the stick will fall as a dead weight. The
repetition of this simple experiment will readily convey to the young
philosopher an idea of the nature of what is termed the _centre of
percussion_.
Note 22, p. 150.--SPINNING OF THE TOP.
It has been stated in the text, that the gyrations of the top depend
exactly upon the same principle as that which produces the _precession
of the equinoxes_; viz. an unequal attractive force exerted upon the
revolving mass. In the one case, this is known to arise from the action
of the sun and moon on the excess of matter about the equatorial
regions of the earth; in the other, from the parts of the top being
unequally affected by gravity, while it is spinning in an inclined or
oblique position. To those philosophers who have condescended to read
the present work, if there be any such, and are thereby induced to
pursue the investigation of a subject which has hitherto excited far
too little attention, we beg to submit the following remarks:--
If a top could be made to revolve on a point without friction, and in a
vacuum, in the case of its velocity being _infinite_, it would continue
to revolve for ever, in the same position, without gyration. If the
velocity were _finite_, it would for ever remain unchanged in position,
in the event of the centre of gravity being directly over the point of
rotation. In any other position (supposing its velocity very great,
although not infinite) there would arise a continued uniform gyration;
the line which passes through the point of rotation, and the centre of
gravity, always making the same angle with the horizon, or describing
the same circle round the zenith. But in all artificial experiments the
circumstances are very remarkably changed; if, indeed, the centre of
gravity happens to be situated perpendicularly over the point of
rotation, the top will continue quite steady, or _sleeping_, as it is
termed, till nearly the whole of its velocity of rotation is expended.
In any other position the top begins to gyrate, but reclining at all
times on the outside of its physical point of gyration, the top is
uniformly impelled inwards; and this (when the velocity is
considerable, and the point broad) acts with a force sufficient for
carrying the top towards its quiescent or _sleeping_ point; but when
the velocity is much diminished, this power becomes feeble, the
gyrations increase in diameter, and the top ultimately falls.
Note 23, p. 161.--THE MECHANICAL POWERS.
The mechanical powers are all founded upon the principle that _the
lengths of circles are in proportion to their diameters_; for it is an
immediate consequence of this property of the circle, that if a rod of
iron, or beam of wood, be placed on a point or pivot, so that it may
move round its prop, the two ends will go through parts of circles,
each proportioned to that arm of the beam to which it belongs; the two
circles will be equal if the pivot is in the centre or middle point of
the beam; but if it is nearer one end than the other, say five times,
that end will pass through a circular space, or _arc_, five times
shorter than the circular space the other end goes through in the same
time. If, then, the end of the long beam goes through five times the
space, it must move with five times the swiftness of the short end,
since both move in the same time; and, therefore, any force applied to
the long end must overcome the resistance of five times that force
applied at the opposite end, since the two ends move in contrary
directions; hence one pound placed at the long end would balance five
placed at the short end.
The beam we have been describing constitutes the first of the
mechanical powers, and is termed the LEVER. There are, besides, five
others, viz. the _wheel and axle_; the _inclined plane_; the _screw_;
the _pulley_; and the _wedge_; out of the whole, or a part of which, it
will be found that every mechanical engine or piece of machinery is
constructed.
THE LEVER being the simplest of all the mechanic powers, is in general
considered the first. It is an inflexible rod or bar of any kind, so
disposed as to turn on a pivot or prop, which is always called its
_fulcrum_. It has the weight or resistance to be overcome attached to
some one part of its length, and the power which is to overcome that
resistance applied to another; and, since the _power_, _resistance_,
and _fulcrum_ admit of various positions with regard to each other, so
is the lever divided into three kinds or modifications, distinguished
as the first, second, and third kinds of lever. That portion of it
which is contained between the fulcrum and the power, is called the
acting part or arm of the lever; and that part which is between the
fulcrum and resistance, its resisting part or arm.
In the lever of the first kind, the fulcrum is placed between the power
and the resistance. A poker, in the act of stirring the fire, well
illustrates this subject; the bar is the _fulcrum_, the hand the power,
and the coals the resistance to be overcome. Another common application
of this kind of lever is the crow-bar, or hand-spike, used for raising
a large stone or weight. In all these cases power is gained in
proportion as the distance from the fulcrum to the power, or part where
the men apply their strength, is greater than the distance from the
fulcrum to that end under the stone or weight. A moment’s reflection
will show the rationale of this fact; for it is evident that if both
the arms of the lever be equal, that is to say, if the fulcrum be
midway between the power and weight, no advantage can be gained by it,
because they pass over equal spaces in the same time; and, according to
the fundamental principle already laid down, _as advantage or power is
gained, time must be lost_; but, since no time is lost under such
circumstances, there cannot be any power gained. If, now, we suppose
the fulcrum to be so removed towards the weight, as to make the acting
arm of the lever three times the length of the resisting arm, we shall
obtain a lever which gains power in the proportion of three to one,
that is, a single pound weight applied at the upper end will balance
three pounds suspended at the other. A pair of scissors consists of two
levers of this kind, united in one common fulcrum; thus the point at
which the two levers are screwed together is the fulcrum; the handles
to which the power of the fingers is applied, are the extremities of
the acting part of the levers, and the cutting part of the scissors are
the resisting parts of the levers; the longer, therefore, the handles,
and the shorter the points of the scissors, the more easily you cut
with them. A person who has any hard substance to cut, without any
knowledge of the theory, diminishes as much as possible the length of
the resisting arms, or cutting part of the scissors, by making use of
that part of the instrument nearest the screw or rivet. Snuffers are
levers of a similar description; so are most kind of pincers, the power
of which consists in the resisting arm being very short in comparison
with the acting one.
In the lever of the second kind, the resistance or weight is between
the fulcrum and the power. Numberless instances of its application
daily present themselves to our notice; amongst which may be enumerated
the common cutting knife, used by last and patten makers, one end of
which is fixed to the work-bench by a swivel-hook. Two men carrying a
load between them, by one or more poles, as a sedan chair, or as
brewers carrying a cask of beer, in which case either the back or front
man may be considered as the fulcrum, and the other as the power. Every
door which turns upon its hinges is a lever of this kind; the hinges
may be considered as the fulcrum, or centre of motion; the whole door
is the weight to be moved, and the power is applied to that side on
which the handle is usually fixed. Nut-crackers, oars, rudders of
ships, likewise fall under the same division. The boat is the weight to
be moved, the water is the fulcrum, and the waterman at the oar is the
power. The masts of ships are also levers of the second kind, for the
bottom of the vessel is the fulcrum, the ship the weight, and the wind
acting against the sail is the moving power. In this kind of lever the
power or advantage is gained in proportion as the distance of the power
is greater than the distance of the weight from the fulcrum; if, for
instance, the weight hang at one inch from the fulcrum, and the power
acts at five inches from it, the power gained is five to one; because,
in such a case, the power passes over five times as great a space as
the weight. It is thus evident why there is considerable difficulty in
pushing open a heavy door, if the hand is applied to the part next the
hinges, although it may be opened with the greatest ease in the usual
method. In the third kind of lever, the fulcrum is again at one of the
extremities, the weight or resistance at the other; and it is now the
power which is applied between the fulcrum and resistance. As in this
case the weight is farther from the centre of motion than the power,
such a lever is never used, except in cases of absolute necessity, as
in the case of lifting up a ladder perpendicularly, in order to place
it against a wall. The man who raises it cannot place his hands on the
upper part of the ladder; the power, therefore, is necessarily placed
much nearer the fulcrum than the weight; for the hands are the power,
the ground the fulcrum, and the upper part of the ladder the weight.
The use of the common fire-tongs is another example, but the
circumstance that principally gives this lever importance is, that the
limbs of men and animals are actuated by it; for the bones are the
levers, while the joints are the fulcra, and the muscles which give
motion to the limbs, or produce the power, are inserted and act close
to the joints, while the action is produced at the extremities; the
consequence of such an arrangement is, that although the muscles must
necessarily exert an enormous contractile force to produce great action
at the extremities, yet a celerity of motion ensues which could not be
equally well provided for in any other manner. We may adduce one
example in illustration of this fact. In lifting a weight with the
hand, the lower part of the arm becomes a lever of the third kind; the
elbow is the fulcrum; the muscles of the fleshy part of the arm the
power; and as these are nearer to the elbow than the hand, it is
necessary that their power should exceed the weight to be raised. The
disadvantage, however, with respect to power, is more than compensated
by the convenience resulting from this structure of the arm; and it is
no doubt that which is best adapted to enable it to perform its various
functions. From these observations it must appear, that although this
arrangement must be mentioned as a modification of the lever, it
cannot, in strictness, be called a mechanical power; since its
resisting arm is in all cases, except one, longer than the acting arm,
and in that one case is equal to it, on which account it never can gain
power, but in most instances must lose it.
THE WHEEL AND AXLE is the next mechanical power to be considered; it
must be well known to every reader who has seen a village well; for it
is by this power that the bucket is drawn up, although in such cases,
instead of a wheel attached to the axle, there is generally only a
crooked handle, which answers the purpose of winding the rope round the
axle, and thus raising the bucket, as may be seen in the engraving at
the head of our third chapter. It is evident, however, that this
crooked handle is equivalent to a wheel; for the handle describes a
circle as it revolves, while the straight piece which is united to the
axle corresponds with the spoke of a wheel. This power may be resolved
into a lever; in fact, what is it but a lever moving round an axle? and
always retaining the effect gained during every part of the motion, by
means of a rope wound round the butt end of the axle; the spoke of the
wheel being the long arm of the lever, and the half diameter of the
axle its short arm. The axle is not in itself a mechanical power, for
it is as impotent as a lever whose fulcrum is in the centre; but add to
it the wheel, and we have a power which will increase in proportion as
the circumference of the wheel exceeds that of the axle. This arises
from the velocity of the circumference being so much greater than that
of the axle, as it is farther from the centre of motion; for the wheel
describes a great circle in the same space of time that the axle
describes a small one; therefore the power is increased in the same
proportion as the circumference of the wheel is greater than that of
the axle. Those who have ever drawn a bucket from a well by this
machine, must have observed, that as the bucket ascended nearer the top
the difficulty increased: such an effect must necessarily follow from
the views we have just offered; for whenever the rope coils more than
once the length of the axle, the difference between its circumference
and that of the wheel is necessarily diminished. To the principle of
the wheel and axle may be referred the capstan, windlass, and all those
numerous kinds of cranes which are to be seen at the different wharfs
on the banks of the river Thames. It is scarcely necessary to add that
the force of the windmill depends upon a similar power. The _treadmill_
furnishes another striking example. The wheel and axle is sometimes
used to multiply motion, instead of to gain power, as in the
multiplying wheel of the common jack, to which it is applied when the
weight cannot conveniently have a long line of descent; a heavy weight
is in this case made to act upon the axle, while the wheel, by its
greatest circumference, winds up a much longer quantity of line than
the simple descent of the weight could require, and thus the machine is
made to go much longer without winding than it otherwise would do.
THE PULLEY is a power of very extensive application. Every one must
have seen a pulley; it is a circular and flat piece of wood or metal,
with a string which runs in a groove round it. Where, however, this is
fixed, it cannot afford any power to raise a weight; for it is evident
that, in order to raise it, the power must be greater than the weight,
and that if the rope be pulled down one inch, the weight will only
ascend the same space; consequently, there cannot be any mechanical
advantage from the arrangement. This, however, is not the case where
the pulley is not fixed. Suppose one end of the rope be fastened to a
hook in the ceiling, and that to the moveable pulley on the rope a cask
be attached, is it not evident that the hand applied to the other
extremity of the rope will sustain it more easily than if it held the
cask suspended to a cord without a pulley? Experience shows that this
is the fact, and theory explains it by suggesting that the fixed hook
sustains half the weight, and that the hand, therefore, has only the
other half to sustain. The hook will also afford the same assistance in
raising the weight as in sustaining it; if the hand has but one half
the weight to sustain, it will also have only one half the weight to
raise; but observe, says Mrs. Marcet, that in raising the weight, the
velocity of the hand must be double that of the cask; for, in order to
raise the weight one inch, the hand must draw each of the strings one
inch; the whole string is therefore shortened two inches, while the
weight is raised only one. Pulleys then act on the same principle as
the lever, the deficiency of strength of the power being compensated by
its superior velocity. It will follow, from these premises, that the
greater the number of pulleys connected by a string, the more easily
the weight is raised, as the difficulty is divided amongst the number
of strings, or rather of parts into which the string is divided by the
pulleys. Several pulleys, thus connected, form what is called a system,
or tackle of pulleys. They may have been seen suspended from cranes, to
raise goods into warehouses, and in ships to draw up the sails.
THE INCLINED PLANE is a mechanic power which is seldom used in the
construction of machinery, but applies more particularly to the moving
or raising of loads upon slopes or hills, as in rolling a cask up or
down a sloping plank into or out of a cart or cellar, or drawing a
carriage up a sloping road or hill, all which operations are performed
with less exertion than would be required if the same load were lifted
perpendicularly. It is a power which cannot be resolved into that of
the lever: it is a distinct principle, and those writers who have
attempted to simplify the mechanical powers, have been obliged to
acknowledge the inclined plane is elementary. The method of estimating
the advantage gained by this mechanical power is very easy; for just as
much as the length of the plane exceeds its perpendicular height, so
much is the advantage gained; if, for instance, its length be three
times greater than its height, a weight could be drawn to its summit
with a third part of the strength required for lifting it up at the
end; but, in accordance with the principle so frequently alluded to,
such a power will be at the expense of time, for there will be three
times more space to pass over. The reason why horses are eased by
taking a zig-zag direction, in ascending or descending a steep hill,
will appear from the preceding account of the action of the inclined
plane, because in this way the effective length of the inclining
surface is increased while its height remains the same.
THE WEDGE is rather a compound, than a distinct mechanical power; since
it is composed of two inclined planes, and in action frequently
performs the functions of a lever. It is sometimes employed in raising
bodies; thus the largest ship may be raised to a small height by
driving a wedge below it; but its more common application is that of
dividing and cleaving bodies. As an elevator, it resembles exactly the
inclined plane; for the action is obviously the very same, whether the
wedge be pushed under the load, or the load be drawn under [sic] the
wedge. But when the wedge is drawn forward, the percussive tremor
excited destroys, for an instant, the adhesion or friction at its
sides, and augments prodigiously the effect. From this principle
chiefly is derived the power of the wedge in rending wood and other
substances. It then acts besides as a lever, insinuating itself into
the cleft as fast as the parts are opened by the vibrating concussion.
To bring the action of the wedge, therefore, under a strict
calculation, would be extremely difficult, if not impossible. Its
effects are chiefly discovered by experience. All the various kinds of
cutting tools, such as axes, knives, chisels, saws, planes, and files,
are only different modifications of the wedge.
THE SCREW is a most efficient mechanic power, and is of great force and
general application. It is in reality nothing more than an inclined
plane formed round a cylinder, instead of being a continued straight
line. Its power is, therefore, estimated by taking its circumference,
and dividing this by the distance between any two of its threads; for
what is taking the circumference of a screw, but another mode of
measuring the length of the inclined plane which wraps round it? and
taking the distance between one thread and the next to it, is but
measuring the rise of that inclined plane in such length; and from the
properties of the inclined plane, it follows, that the closer the
threads of a screw are together in proportion to its diameter, the
greater will be the power gained by it.
Note 24, p. 165.--THE CYCLOID.
A _cycloid_ is a peculiar curve line; and is described by any one point
of a circle as it rolls along a plane, and turns round its centre;
thus, for instance, the nail on the felly of a cart-wheel traces a
cycloid in the air as the wheel proceeds. This curve is distinguished
by some remarkable properties, the most important of which is that
mentioned in the text, viz. that any body moving in such a curve, by
its own weight, or swing, will pass through all distances of it in
exactly the same time; and it is for such a reason that pendulums are
made to swing in cycloids, in order that they may move in equal times,
whether they go through a long or a short part of the same curve. Where
the arc described is small, a portion of the circle will be
sufficiently accurate, because it will be seen that such an arc will
not deviate much from an equal portion of a cycloidal curve.
The cycloid is remarkable as being that path, with the exception of the
perpendicular, through which a body will move with the greatest
velocity; suppose, for example, a body is to descend from any one point
to any other, by means of some force acting on it, together with its
weight: a person unacquainted with mechanics would say at once, that a
straight line is the path it must take to effect this in the shortest
possible time, since that is the shortest of all lines that can be
drawn between two points. Undoubtedly it is the shortest;
notwithstanding which, however, the body would be longer in traversing
it, than in moving through a cycloid. If a body were to move through a
space of fifty or a hundred yards, by its weight and some other force
acting together, the way it must take to do this in the shortest
possible time is by moving in a cycloid. It is supposed that birds
which build in the rocks possess an instinctive knowledge of this fact,
and drop or fly down from height to height in this course. There is
certainly a general resemblance between the curved path they describe
on such occasions, and the cycloid, but it would be difficult to
establish the fact by experiment. Man, however, has founded upon this
principle some applications of great value in practical mechanics. In
Switzerland, and in several parts of Germany, for example, slides have
been constructed along the sides of mountains, by which the timber
felled near their summits is conducted with extreme rapidity to the
distant valleys.
Note 25, p. 171.--BILLIARDS.
This interesting game is of French origin (_billiard_, of _bile_, and
from the Latin, _pila_, a ball). It was hailed as a favourite diversion
at the court of Henry III. of France; and was thence communicated to
all the courts of modern Europe. To the novice it may appear as a game
of accidents and chances, but experience has enabled us to determine
the effects of the stroke given to a ball with wonderful precision; and
it is quite extraordinary to observe the accuracy with which an
accomplished player can effect his object, by measuring with his eye
the angle at which he should make the stroke, the position of the ball
with respect to the cushion, and the distance of the point of the ball
from its centre, at which it should be struck. By such skilful
management the ball may be made to take directions which would, at
first view, be regarded as contrary to all the known laws of motion,
such, for instance, as passing round an object, such as a hat placed on
the table, and to strike a ball behind it into a pocket.
Upon this subject the reader should consult a work by M. Mingaud, which
has been translated and published by John Thurston, the celebrated
billiard-table maker of Catherine Street, Strand. We understand that a
still more complete work may be expected from the same source.
Note 26, p. 172.--COLLISION OF BODIES.
In investigating the effects produced upon bodies by collision, it is
necessary to distinguish between elastic and non-elastic substances,
since their motions after impact are governed by very different laws.
If two bodies, _void of elasticity_, move in one right line, either the
same or contrary ways, so that one body may strike directly against
another, let the _sum_ of their motions before the stroke, if they move
the same way, and the _difference_ of their motions, if contrary ways,
be divided into two such parts as are proportional to the quantities of
matter in the bodies, and each of those parts will respectively exhibit
the motion of each body after the stroke: for example, if the
quantities of matter in the bodies be as _two_ to _one_, and their
motions before the stroke as _five_ and _four_, then the sum of their
motions is _nine_, and the difference is _one_; and therefore, when
they move the same way, the motion of that body, which is as _two_,
will, after the stroke, be _six_, and the motion of the other, _three_;
but, if they move in contrary directions, the motion of the greater
body after the stroke will be _two-thirds of one_, and of the lesser
body _one-third of one_; for, since the bodies are void of elasticity,
they will not separate after the stroke, but move together with one and
the same velocity; and, consequently, their motions will be
proportional to their quantities of matter; and it follows from the
fact of action and reaction being equal, that no motion is either lost
or gained by the stroke when the bodies move the same way; because,
whatever motion one body imparts to the other, so much must it lose of
its own; and, consequently, the _sum_ of their motions before the
stroke is neither increased nor diminished by the stroke, but is so
divided between the bodies, as that they may move together with one
common velocity; that is, it is divided between the bodies in
proportion to their quantities of matter: but it is otherwise, where
the bodies move in opposite directions, or contrary ways, for then the
smaller motion will be destroyed by the stroke, as also an equal
quantity of the greater motion, because action and reaction are equal;
and the bodies, after the stroke, will move together equally swift,
with the _difference_ only of their motions before the stroke;
consequently, that difference is, by means of the stroke, divided
between them in proportion to their quantities of matter.
The several particular cases, concerning the collision of bodies, may
be reduced to four general ones; viz.
1st. It may be, that one body only is in motion at the time of the
stroke.
2nd. They may both move one and the same way.
3rd. They may move in direct opposition to each other, and that with
equal quantities of motion.
4th. They may be carried with unequal motions in directions contrary to
each other.
As the bodies may be either equal or unequal, each of these four
general cases may be considered as consisting of two branches.
As to the first, if a body in motion strikes another equal body at
rest, they will, according to the proposition, move together each of
them with one half of the motion that the body had which was in motion
before the stroke; and since the quantity of motion in any body is as
the product arising from the multiplication of its quantity of matter
into its velocity, the common velocity of the two bodies will be but
one half of the velocity of the moving body before the stroke.
As to the second general case, where both the bodies are in motion
before the stroke, and move one and the same way. In order to find
their common velocity after impact, let the sum of their motions before
the stroke be divided by the sum of the bodies, and the quotient will
express the common velocity.
As to the third general case, where the bodies move in direct
opposition to each other, if they have equal quantities of motion, they
will upon the stroke lose all their motion, and continue at rest; for,
by the proposition, the bodies after impact will be carried with the
difference of their motions before the stroke; which difference, in
such a case, is nothing.
When two bodies meet with unequal quantities of motion, if the
difference of their motions be divided by the sum of the bodies, the
quotient will express their common velocity after the stroke; for, by
the proposition, the difference of their motions before the stroke is
equal to the sum of their motions after the stroke; consequently, that
difference divided by the sum of the bodies must give the velocity.
Such are the principal laws which govern the collision of bodies devoid
of elasticity. The motions of elastic bodies are determined by
different rules: for when they are perfectly elastic, the velocity
gained by the body struck, and the velocity lost by the striking body,
will be twice as great as if the bodies were perfectly inelastic. In
estimating, therefore, the motions of such bodies, we may first
consider what they would have been after impact, had they been
inelastic, and thence deduce the desired conclusion. See Helsham’s
Lectures, a work in which the subject appears to be very clearly
treated.
Note 27, p. 181.--DRUIDICAL REMAINS.
Karn-brêh hill rises a little to the south-west of Redruth in Cornwall,
to an elevation of 697 feet. Its principal interest is derived from the
speculations of the antiquary, Doctor Borlase, who regarded it as
having been once the grand centre of druidical worship; and he asserts,
in his Antiquities of Cornwall, that, at this very time, the remains of
those monuments which were peculiar to that priesthood may be
discovered, such as _rock-basins_, _circles_, _rock-idols_,
_cromlechs_, _karns_, _caves_, _religious enclosures_, _logan stones_,
_a gorseddau_, or place of elevation, whence the druids pronounced
their decrees, and the traces of a _grove of oaks_. This is all very
ingenious and imposing, and may be easily believed by those who have
either not visited the spot, or, having visited it, not viewed the
objects with geological eyes. There is no ground whatever for
considering the druidical monuments of Dr. Borlase as the works of man:
on the contrary, they are evidently the results of the operation of
time and the elements, the usual agents employed by Nature in the
decomposition of mountain masses: but the age of antiquarian illusion
is past; the light of geological science has dispelled the phantoms
created by the wizard Fancy, just as the rising sun dissolves the
mystic forms which the most common object assumes in twilight, when
viewed through the medium of credulity and superstition. The
“rock-basins” of antiquaries are rounded cavities on the surface of
rocks, and are occasionally as spheroidal internally as if they had
been actually formed by a turning-lathe. It was this artificial
appearance which first suggested the hypothesis concerning their
origin, and induced the antiquary to regard them as pools of
lustration. It may, however, be remarked, in the first place, that,
supposing them to have been the works of the druids, these priests must
have been indefatigable artists, for there is scarcely a block of
granite on which one or more of such pools are not visible, although
some are, undoubtedly, much more complete and imposing than others. We
shall introduce to the reader an account of these rock-basins in the
words of their great defender, and we think that he will be amused with
the ingenuity and confidence with which the antiquary dwells upon every
appearance, and bends the facts to suit his favourite theory. “Since no
author has mentioned, and attempted to explain these monuments, let us
see what light and assistance their shape and structure, exposition,
number, and place, considered together with the customs and known rites
of antiquity, may afford us in this untrodden path. Of these basins
there are two sorts; some have lips or channels to them, others have
none; and therefore, as those lips are manifestly the works of design,
not of accident, those that have so material a difference must needs
have been intended for a different use, and yet both these sorts seem
to be the works of the same people, for there is a multitude of these
basins which have no lips or outlets, as well as those which have, to
be seen on Karn-brêh hill, and elsewhere, on contiguous rocks. Their
shape is not uniform; some are quite irregular, some oval, and some are
exactly circular. Their openings do not converge in the top as a jar or
hogshead, but rather spread and widen, as if to expose the hollow as
much as possible to the skies. Some have little falls into a larger
basin, which receives their tribute, and detains it, having no outlet.
Other large ones intermixed with little ones have passages from one to
another, and, by successive falls uniting, transmit what they receive
into one common basin, which has a drain to it, that serves itself and
all the basins above it.”
“The lips do not all point in the same direction, some tending to the
south, some to the west, others to the north, and others again to the
intermediate points of the compass; _by which it seems as if the makers
had been determined in this particular, not by any mystical veneration
for one region of the heavens more than another, but by the shape and
inclination of the rock, and for the most easy and convenient outlet_.”
We must here beg the reader to pause. The above remark is really too
valuable to be suffered to pass without some notice. And so the absence
of all design and arrangement is adduced as a proof of their artificial
origin! What would Dr. Borlase have said, had all these lips been found
to point in the same direction? But to proceed:
“The size of rock-basins is as different as their shape; they are
formed from six feet to a few inches in diameter. Many uses may suggest
themselves to the imaginations of the curious from the description of
these new, and hitherto scarce-mentioned monuments; in order,
therefore, to obviate some prepossessions, and prevent the mind from
resting so far on groundless suppositions as may make it more difficult
to embrace the truth, I shall first consider what, in all probability,
_cannot_ have been the design of them.”
The doctor then proceeds to show that they could never have been
intended for evaporating salt; nor for pounding tin ore, nor for
receiving obelisks, or stone deities, nor for altars; and then suggests
that they could be no other than vessels most ingeniously contrived for
holding holy-water for the rites of washing and purification. “If,”
adds the learned antiquary, “fitness can decide the use--and where
history is deficient, it is all reason that it should--we shall not
long be at a loss. They are mostly placed above the reach of cattle,
frequently above the inspection of man; nay, the stones which have
these basins on them, do not touch the common ground, but stand on
other stones.--Wherefore? but that the water might neither be really
defiled by the former, nor incur the imaginary impurity, which touching
the ground, according to the druid opinion, gave to every thing that
was holy.” We do not know what ideas the druids entertained with
respect to the purity of water, but we have seen water in some of these
pools so impregnated with the excrement of sea-birds, that we must have
been as thirsty as Tantalus, before we could have been induced to cool
our tongues with it.
“But,” adds Dr. Borlase, “there are some basins which have no lip or
channel; and, therefore, as they could not contribute any of their
water to the common store, they _must_ have been appropriated to
another use; and since these are found in the same places with the
others above-mentioned which have outlets or mouths to them, they must
have been subservient to the same system of superstition, though in a
different method.”
“These basins are sometimes found near twenty feet high from the common
surface; and, therefore, being so withdrawn from vulgar eyes, so
elevated from the ground, which was supposed, as I said before, to
defile all, they had likely a proportionably greater degree of
reverence, and their waters accounted more holy, and more efficacious.”
We shall not trouble the reader with any further quotations from this
learned antiquary, except in concluding the history, after the fashion
of melo-dramatists, with a splendid scene, in which, with the author’s
assistance, we shall bring all the performers on the stage, dressed in
appropriate costume, and surrounded by all the pomp of druidical
worship.
“From these basins,” says Dr. Borlase, “on solemn occasions the
officiating druid, standing on an eminence, sanctified the congregation
with a more than ordinarily precious lustration before he expounded to
them, or prayed for them, or gave forth his decisions. This water he
drank, or purified his hands in, before it touched any other vessel,
and was consequently accounted more sacred than the other holy-water.
To these more private basins, during the time of libation, the priest
might have recourse, and be at liberty to judge by the quantity,
colour, motion, and other appearances in the water, of future events,
of dubious cases, without danger of contradiction from the people
below. This water might serve to mix their mistletoe withal, as a
general antidote: for, doubtless, those who would not let it touch the
ground, would not mix this their divinity (the mistletoe) with common
water. Oak leaves, without which the druid rites did scarce ever
proceed, ritually gathered and infused, might make some very medicinal
or incantorial potion. Lastly, libations of water were never to be made
to their gods, but when they consisted of this purest of all water, as
what was immediately come from the heavens, and partly therefore
thither to be returned, before it touched any other water or any other
vessel whatsoever, placed on the ground.”
“As _logan_, or rocking-stones, were some of the _piæ fraudes_ of the
druids, the basins found on them might be used to promote the juggle;
by the motion of the stone the water might be so agitated, as to delude
the enquirer by a pretended miracle; might make the criminal confess;
satisfy the credulous; bring forth the gold of the rich; and make the
injured, rich as well as poor, acquiesce in what the druid thought
proper.”
Sorry are we to destroy a web which has been so ingeniously woven by
its author; but the interests of truth admit not of compromise. Dr.
Macculloch, in an interesting paper, published in the Transactions of
the Geological Society, on the decomposition of the granite tors of
Cornwall, has justly observed, that the true nature of these
rock-basins may be easily traced by inspecting the rocks themselves. On
examination, they will always be found to contain distinct grains of
_quartz_, and fragments of the other constituent parts of the granite.
A small force is sufficient to detach from the sides of these cavities
additional fragments, showing that a process of decomposition is still
going on under favourable circumstances. The principal of these
circumstances is the presence of water, or rather the alternate action
of air and water. If a drop of water can only make an effectual
lodgement on a surface of this granite, a small cavity is sure to be
sooner or later produced; this will insensibly enlarge as it becomes
capable of holding more water; and the sides, as they continue to
waste, will necessarily retain an even and rounded cavity, on account
of the uniform texture of the rock. This explanation is sufficiently
satisfactory: in addition to which, it may be stated, that these very
basins not unfrequently occur on the perpendicular sides of rocks, as
may be distinctly seen in the granite of Scilly, and in the gritstone
rocks in the park of the late Sir Joseph Banks, in the parish of
Ashover, in Derbyshire; a fact which at once excludes the idea of their
artificial origin.
The other grotesque and whimsical appearances of rocky masses, such as
_rock idols_, _logan stones_, _&c._ are to be explained by the tendency
which granite possesses of wearing more rapidly on the angles and edges
than on the sides; thus, then, upon simple and philosophical
principles, are such appearances to be satisfactorily accounted for,
and the _phantasmagoria_ of Borlase vanishes as the light penetrates
the theatre so long dedicated to its exhibition.
We shall conclude this note with a few observations upon the celebrated
logan, or logging, stone, near the Land’s End, Cornwall, of which we
present our readers with a faithful sketch.
[Illustration: Mound of stone with a boulder balanced atop a point in
the middle.]
The foundation of this part of the coast is a stupendous group of
granite rocks, which rise in pyramidal clusters to a great altitude,
and overhang the sea. The celebrated _logan stone_ here represented is
an immense block weighing above sixty tons. The surface in contact with
the under rock is of very small extent, and the whole mass is so nicely
balanced, that, notwithstanding its magnitude, the strength of a single
man applied to its under edge is sufficient to make it oscillate. It is
the nature of granite to disintegrate into rhomboidal and tabular
masses, which, by the further operation of air and moisture, gradually
lose their solid angles, and approach the spheroidal form. The fact of
the upper part of the cliff being more exposed to atmospheric agency
than the parts beneath, will sufficiently explain why these rounded
masses so frequently rest on blocks which still preserve the tabular
form; and since such spheroidal blocks must obviously rest in that
position in which their lesser axes are perpendicular to the horizon,
it is equally evident that, whenever an adequate force is applied, they
must vibrate on their point of support.
Although we are thus led to deny the druidical origin of this stone,
for which so many zealous antiquaries have contended, still we by no
means intend to deny that the druids employed it as an engine of
superstition; it is possible that, having observed so curious a
property, they dexterously contrived to make it answer the purposes of
an ordeal, and, by regarding it as the _touch-stone_ of truth,
acquitted or condemned the accused by its motions. Mason poetically
alludes to this supposed property in the following lines:--
“Behold yon huge
And unknown sphere of living adamant,
Which, poised by magic, rests its central weight
On yonder pointed rock; firm as it seems,
Such is its strange and virtuous property,
It moves obsequious to the gentlest touch
Of him whose heart is pure, but to a traitor,
Tho’ e’en a giant’s prowess nerved his arm,
It stands as fixed as Snowdon.”
Note 28, p. 186.--ANIMAL SUCTION.
We are indebted to Sir Everard Home for a description of that peculiar
structure by which several species of animals are enabled to sustain
their bodies in opposition to the force of gravity. His first paper
upon this subject is published in the 106th volume of the Philosophical
Transactions, in which he says, he was not aware that any animal,
larger than the house-fly, was endowed by nature with such a power, so
as to admit of examination, until Sir Joseph Banks mentioned that the
_lacerta gecko_, a species of lizard, which is a native of the island
of Java, comes out of an evening from the roofs of the houses, and
walks down the smooth, hard, and polished chinam walls, in search of
the flies which settle upon them, and which are its natural food, and
then runs up again to the roof of the house. Sir Joseph, while at
Batavia, amused himself with catching this animal, by standing close to
the wall, at some distance from the lizard, with a long flattened pole,
which being made suddenly to scrape the surface of the wall, knocked
the animal down. He presented Sir Everard with a specimen weighing five
ounces and three quarters, avoirdupois, which enabled him to ascertain
the peculiar mechanism by which the feet of this animal can keep their
hold of a smooth, hard, perpendicular wall, and carry up so large a
weight as that of its body.
The foot has five toes, at the end of each of which, except that of the
thumb, is a very sharp and much curved claw; on the under surface of
each toe are sixteen transverse slits, leading to so many cavities or
pockets, the depth of which is nearly equal to the length of the slit
that forms the orifice; they all open forward, and the external edge of
each opening is serrated, like the teeth of a small-toothed comb. The
cavities, or pockets, are lined with a cuticle, and the serrated edges
are also covered with it. The structure just described is supplied with
various muscles, whose action is to draw down the claw, open the
orifices of the pockets, and turn down the serrated edges upon the
surface on which the animal stands. Upon examining attentively the
under surface of the toes, when the pockets are closed, Sir Everard
Home was struck with their resemblance to the surfaces of that portion
of the _Echineis remora_, or sucking fish, by which it attaches itself
to the shark, or to the bottom of ships; and it consequently suggested
the probability of obtaining, from an examination of this latter
apparatus, much useful information which might be applicable to the
subject of the lizard, more especially as the parts of which it is
composed are so much larger, and therefore more within the reach of
anatomical examination.
The surface on the top of the head of this fish, fitted for adhesion,
is of an oval form, and bears a considerable proportion to the size of
the whole animal; it is surrounded by a broad, loose, movable edge,
capable of applying itself closely to the surface on which it is
placed; and it is evident that when the external edge is so applied,
and the cartilaginous plates are raised up, the interstices must become
so many vacua, and the serrated edge of each plate will keep a
sufficient hold of the substance on which it rests to retain it in that
position, assisted by the pressure of the surrounding water, without a
continuance of muscular exertion. It thus appears that the adhesion of
the _sucking fish_ is produced by so many vacua being formed through an
apparatus worked by the voluntary muscles of the animal, and the
pressure of the surrounding water.
From the similarity of the mechanism of the under surface of the toes
of the _lacerta gecko_, there can be no doubt that the purpose to which
it is applied is the same: but as in the one case the adhesion is to
take place under water, and is to continue for longer periods, the
means are more simple; in the other, where the mechanism is to be
employed in air, under greater disadvantages with respect to gravity,
and is to last for very short periods, and then immediately afterwards
to be renewed, a more delicate structure of parts, a greater
proportional depth of cavities, and more complex muscular structure,
become necessary.
Having ascertained the principle on which an animal of so large a size
as the _lacerta gecko_ is enabled to support itself in its progressive
motion against gravity, Sir E. Home felt himself more competent to
inquire into the mechanism by which the common fly is enabled, with so
much facility, to support itself in still more disadvantageous
situations. In the natural size the feet of the fly are so small, that
nothing can be determined respecting them; Keller was the first person
who made a drawing of the fly’s foot in a highly magnified state, in
which the concave surfaces are visible, and which, no doubt, like those
of the lizard above described, are employed to form vacua, which enable
the fly to move under such disadvantageous circumstances. Mr. Bauer,
who has so greatly distinguished himself in microscopic researches, was
judiciously enlisted into the service of Sir E. Home upon this
occasion; and he has shown that this principle, on which progressive
motion against gravity depends, is very extensively employed by nature
in the structure of the feet of insects; and Sir Everard observes,
that, now this structure is known, it can be readily demonstrated by
looking at the movement of the feet of any insect upon the inside of a
glass tumbler, through a common magnifying glass; the different suckers
are readily seen separately to be pulled off from the surface of the
glass, and reapplied to another part.
In consequence of the expedition to the polar regions, Sir E. Home was
enabled to obtain and examine the foot of the walrus, in which he
detected a resemblance in structure to that of the fly; and it is not a
little curious that two animals so different in size should have feet
so similar in their use. In the fly the parts require to be magnified
one hundred times to render the structure distinctly visible; and in
the walrus the parts are so large, as to require being reduced four
diameters, to bring them within the size of a quarto page.
Nor is progressive motion, the only function in which Nature avails
herself of the pressure of the atmosphere for the accomplishment of her
purposes. The act of feeding is continually effected in this manner.
The operation of sucking is too familiar to require comment. It may
not, perhaps, be so generally known, that it is by the very same
process that bees reach the fine dust and juices of hollow flowers,
like the honeysuckle, and some species of foxglove, which are too
narrow to admit them. They fill up the mouth of the flower with their
bodies, and suck out the air, or at least a large portion of it, by
which the soft sides of the flower are made to collapse, and the juice
and dust are squeezed towards the insect, as completely as if the hand
had pressed it externally. It is by a similar process that the oyster
is enabled to close its shell so firmly; for, if a hole be bored in it,
it may be opened without the least difficulty.
Note 29, p. 191.--ACCIDENTAL DISCOVERIES.
Those who are not acquainted with the operations by which the mind is
enabled to arrive at truth, are too apt to attribute to accident that
which is the result of great intellectual labour and acuteness.
Observation, analogy, and experiment are the three great
stepping-stones by which the philosopher is enabled to ascend from
darkness to light: it is true that his foot may accidentally be
placed upon the first, but his own efforts are required to complete
the ascent. To the mass of mankind the preliminary step is obvious,
and they at once conclude that the succeeding ones are equally easy
and simple. In this view of the subject, it was by accident that Sir
Isaac Newton discovered the laws of gravitation, for his mind was
directed to the investigation by the accidental fall of an apple from
its tree; it was by accident that Galileo discovered the isochronous
movement of the pendulum, for it was suggested by the vibration of a
chandelier: but how many persons might have witnessed the fall of an
apple, or the vibration of a chandelier, without arriving at similar
truths? It has been said that we are indebted for the important
invention in the steam-engine, termed _hand gear_, by which its
valves or cocks are worked by the machine itself, to an idle boy of
the name of Humphrey Potter, who, being employed to stop and open a
valve, saw that he could save himself the trouble of attending and
watching it, by fixing a plug upon a part of the machine which came
to the place at the proper times, in consequence of the general
movement. If this anecdote be true, what does it prove? That Humphrey
Potter might be very idle, but that he was, at the same time, very
ingenious. It was a contrivance, not the result of accident, but of
acute observation and successful experiment. Glass is said to have
been discovered by persons having accidentally kindled a fire on the
sandy shore with sea-weed, when the alkali from the ashes united with
the silex of the sand; and Pliny tells us that _minium_, or red lead,
was first recognised, in consequence of a fire that took place at the
Piræus at Athens, where some _ceruse_, which had been exposed to the
fire, had been found converted into a red substance. A thousand such
accidents might be related, were we not affording a sample rather
than a catalogue. We are endeavouring to combat a popular but
mischievous error; and we are happy at finding the same feeling
expressed in a work which, from its extensive circulation, must prove
highly useful in correcting it. “Very few discoveries,” says the
author, “have been made by chance and by ignorant persons; much fewer
than is generally supposed. They are generally made by persons of
competent knowledge, and who are in search of them. The improvement
of the steam-engine by Watt resulted from the most learned
investigation of mathematical, mechanical, and chemical truths.
Arkwright devoted many years, five at least, to his invention of
spinning-jennies. The new process of refining sugar, by which more
money has been made in a shorter time, and with less risk and
trouble, than was perhaps ever gained by an invention, was discovered
by Mr. Howard, a most accomplished chemist, and it was the fruit of a
long course of experiments, in the progress of which, known
philosophical principles were constantly applied, and one or two new
principles ascertained.”--_Library of Useful Knowledge._
Note 30, p. 193.--WEIGHT OF THE SUPERINCUMBENT OCEAN.
If we include the pressure of the atmosphere, a body at the depth of
100 feet would sustain that of 60 pounds on the square inch; while one
at 4,000 feet, a depth by no means considerable, it would be exposed to
a pressure of about 1,830 pounds. We need not, therefore, feel
surprised, that on the foundering of a ship at sea, though its timbers
part, not a spar floats to the surface; for if the hull has sunk to a
great depth, all that is porous is penetrated with water or greatly
compressed. Captain Scoresby states that when, by the entangling of the
line of the harpoon, a boat was carried down with the whale, it
required after it was recovered two boats to keep it at the surface.
Sir J. Herschel has recorded a melancholy anecdote, which may well be
adduced in farther illustration of our subject:--“After the invention
of the diving-bell, and its success in sub-aqueous processes, it was
considered highly desirable to devise some means of remaining for any
length of time under water, and rising at pleasure without any
assistance. Some years ago an ingenious individual proposed a project
by which this end was to be accomplished. It consisted in sinking the
hull of a ship made quite water-tight, with the decks and sides
strongly supported by shores, and the only entry secured by a stout
trap-door, in such a manner, that by disengaging from within the
weights employed to sink it, it might rise of itself to the surface. To
render the trial more satisfactory, the projector himself made the
first essay. It was agreed that he should sink in twenty fathoms water,
and rise again without assistance at the expiration of twenty-four
hours. Accordingly, making all secure, and provided with the means of
making signals to indicate his situation, this unhappy victim of his
own ingenuity entered and was sunk. No signal was made, and the time
appointed elapsed. The pressure of the water at so great a depth had,
no doubt, been completely under-estimated, and the sides of the vessel
being at once crushed in, the unfortunate projector perished, before he
could even make the signal concerted to indicate his distress.”
Note 31, p. 199.
Hence _pecunia_ from pecus. _Opes_ quasi Oves. See Note 6.
Note 32, p. 207.--THE CAUSE OF IRIDESCENCE.
If a soap-bubble be blown up, and set under a glass, so that the motion
of the air may not affect it, as the water glides down the sides and
the top grows thinner, several colours will successively appear at the
top, and spread themselves from thence in rings down the sides of the
bubble, till they vanish in the same order in which they appeared; at
last a black spot appears at the top, and spreads till the bubble
bursts. Hence it follows that the colours of a body depend in some
degree upon the thickness and density of the particles that compose it;
and that, if the density be changed, the colour will likewise be
changed. That the production of colours depends upon the nature of the
surfaces upon which light falls, is beautifully exemplified by the
iridescence of mother of pearl; and which has been satisfactorily shown
to depend upon a singular peculiarity in the structure of that
substance. On its surface, which to the unassisted eye, and even to the
touch, appears to be finely polished, there are innumerable little
lines, or _grooves_, in some places as many as two or three thousand in
the space of an inch, which, lying parallel, regularly follow each
other in all their windings; by the edges of which the rays of light
are reflected, and the continual change of colour arises from their
continual bendings. Whatever doubts might have existed upon the
subject, some late experiments of Dr. Brewster have dissipated them, by
showing that the colours which play so beautifully on the surface of
mother of pearl, may be communicated by pressure to sealing-wax and
several other substances. The discovery of this fact was in some
measure accidental; he had stuck a piece of mother of pearl on a cement
made of rosin and bees-wax, and on separating this cement he found that
it had acquired the property of exhibiting colours. Several persons who
witnessed the effect, concluded that it arose from the presence of a
thin film of the mother of pearl, which might have scaled off and
adhered to the wax: but such an explanation was at once refuted, by
plunging the wax in acid, which must have dissolved the mother of
pearl, had any been present; but the acid had no effect, and the
colours of the impression remained unimpaired. It is clear, then, that
it is the grooves, as Dr. Brewster conjectured, which occasion the
iridescence in the mother of pearl, as well as in the waxen impression.
In consequence of this curious discovery, Mr. Barton succeeded in
producing the same appearance on glass, and on different metals, by
simply cutting grooved lines on their surface. These lines are so fine
that, without a microscope, they are scarcely visible, and the glass
and the metal appear to retain their polish: yet they and the colours
also may be communicated by an impression, like those from the mother
of pearl, to the wax. In like manner the varying and delicate hues
exhibited by the wings of certain butterflies, arise from the action of
light upon the parallel and equidistant striæ upon their surfaces.
Note 33, p. 224.--VEGETABLE BAROMETERS.
The following are a few of those plants which indicate changes in the
weather:--
_Chickweed_ is an excellent barometer. When the flower expands fully,
we are not to expect rain for several hours; should it continue in that
state, no rain will disturb the summer’s day. When it half conceals its
miniature flower, the day is generally showery; but, if it entirely
shuts up, or veils the white flower with its green mantle, let the
traveller take the hint and put on his great-coat. The different
species of _trefoil_ always contract their leaves at the approach of a
storm; so certainly does this take place, that these plants have
acquired the name of the _husbandman’s barometer_.
The tulip and several of the compound yellow flowers also close before
rain. There is, besides, a species of wood-sorrel, which doubles its
leaves before storms and tempests. The _bauhinia_, or mountain ebony,
_cassia_, and sensitive plants, observe the same habit.
Note 34, p. 225.--SAINT SWITHIN.
The popular adage of _Forty days’ rain after St. Swithin_, is a
tradition which seems to have derived its origin from the following
circumstance. Swithin, or _Swithum_, bishop of Winchester, who died in
868, desired that he might be buried in the open church-yard, and not
in the chancel of the minster, as was usual with other bishops; and his
request was complied with; but the monks, on his being canonized,
considering it disgraceful for the saint to lie in a public cemetery,
resolved to remove the body into the choir, which was to have been done
with solemn procession on the 15th of July. It rained, however, so
violently for forty days together at this season, that the design was
abandoned. “Now, without entering into the case of the bishop,” says
Mr. Howard, in his work on the Climate of London, “who was probably a
man of sense, and wished to set the example of a more wholesome, as
well as a more humble, mode of resigning the perishable clay to the
destructive elements, I may observe, that the fact of the hindrance of
the ceremony by the cause related is sufficiently authenticated by
tradition; and the tradition is so far valuable, as it proves that the
summers in this southern part of our island, were subject, a thousand
years ago, to occasional heavy rains, in the same way as at present.”
Mr. Howard has shown, by a table, that the notion commonly entertained
on this subject, if put strictly to the test of experience, at any one
station, in this part of the island, will be found fallacious; he,
however, very justly observes, that “the opinion of the people on
subjects connected with Natural History is commonly founded, in some
degree, on fact or experience;” and to do justice to the popular
observation in question, he states that, “in a majority of our summers,
a showery period, which, with some latitude as to time and local
circumstances, may be admitted to constitute daily rain for forty days,
does come on about the time indicated by this tradition; not that any
long space before is often so dry as to mark distinctly its
commencement.”
Note 35, p. 230.--THE WHALE.
Did the whale know his own power, he would easily destroy all the
machinery which the art of man could devise for catching him; it would
be only necessary for him to swim on the surface in a straight line in
order to break the thickest rope; but the fish, on being struck by the
harpoon, obeys a natural instinct, which, in this instance, betrays him
to his death. Sir H. Davy, in his Salmonia, observes, that the whale,
not having an air-bladder, can sink to the lowest depths of the ocean,
and mistaking the harpoon for the teeth of a sword-fish, or a shark, he
instantly descends, this being his manner of freeing himself from these
enemies, who cannot bear the pressure of a deep ocean; and from
ascending and descending in small space, he thus puts himself in the
power of the whaler.--_See Note 30._
Note 36, p. 235.--PROGRESSIVE MOTION IN FISHES:
BOATS IMPELLED BY PADDLING, ROWING, &C.
To render the subject to which this note refers farther intelligible,
we may show the means by which a fish moves forward in the water. The
accompanying diagram and demonstration are from Dr. Roget’s Bridgewater
Treatise.
[Illustration: Diagram of fish’s motion.]
The tail is the principal instrument by which the progressive motion is
effected. Thus--suppose that the tail is inclined to the right; if, in
this situation, the muscles of the left side, tending to bring the tail
in a right line with the body, are suddenly thrown into action, the
resistance of the water, by reacting against the broad surface of the
tail in the direction P R, perpendicularly to that surface, will cause
the muscular action to give the whole body an impulse in that
direction; and the centre of gravity, C, will move onwards in the
direction C B, parallel to P R. This impulse is not destroyed by the
farther flexion of the tail towards the left side, because the
principal force exerted by the muscles has already been expended in the
motion from R to M, in bringing it to a straight line with the body;
and the force which carries it on to L is much weaker, and therefore
occasions a more feeble reaction. When the tail has arrived at the
position L, indicated by the dotted outline, a similar action of the
muscles on the right side will create a resistance and an impulse in
the direction of K L, and a motion of the whole body in the same
direction, C A. These impulses being repeated in quick succession, the
fish moves forward in the diagonal C D, intermediate between the
direction of the two forces.
Upon the same principle a boat is impelled by paddling; and the action
of the rudder of a ship in turning the vessel will be readily
understood. In this latter case, however, there is an additional
mechanical advantage; since the point round which the vessel turns, is
beyond the middle and towards the prow, and hence the force applied at
the extremity of the keel acts as by an arm of a lever.
Note 37, p. 236.--FLIGHT OF BIRDS.
In appreciating the mechanical means by which a bird is enabled to
direct its course, we must not omit to take into account the power it
possesses of changing the position of the centre of gravity of its
body, so that the reaction of the air may be modified with regard to
each wing.
Note 38, p. 236.--FLIGHT OF INSECTS.
The command possessed by insects in directing and changing their
course, seems more perfect even than that of birds. Many of them travel
on their wings to immense distances, and, considering their comparative
size, they generally move through the air with greater velocity than
that of birds. Bees have been known to fly great distances from their
hive, in search of food; and the silk-worm moth has travelled more than
a hundred miles in a very short space of time. Many of our readers
have, no doubt, noticed with surprise the apparent facility with which
gnats have accompanied them, although they may have been advancing on
horseback at a full gallop; and the author during the last summer has
been forcibly struck with the manner in which flies and other insects
have kept up with a railway carriage, alternately flying in and out of
the vehicles, as though they had been at perfect rest. Some species
possess a remarkable power of poising themselves in the air, and
hovering for a length of time over the same spot, without falling or
rising, advancing or retreating; the _Dragon-fly_ affords a striking
example of this fact.
Note 39, p. 237.--OBLIQUITY OF THE WINGS OF BIRDS.
In consequence of the manner in which the wings are affixed to the
scapula, they give a stroke to the air in a direction both downwards
and backwards; so that while the former supports the bird, the latter
impels it forward. It is curious to notice that the degree of this
obliquity varies in different birds, and is evidently adapted to their
habits: thus, for instance, birds of prey have a great obliquity of
wing, which better enables them to pursue their victims in a horizontal
course; while those birds which soar to a considerable elevation, in a
nearly vertical direction, as the _Lark_, have scarcely any obliquity
of wing, but strike directly downwards.
Note 40, p. 238.--A MECHANICAL PROPOSITION.
This fact may be demonstrated by converting the triangle into a
parallelogram, of which one of the sides of the triangle will become
its diagonal: the other two sides will, of course, represent two forces
equivalent to such diagonal, which, acting in opposition to it, must
produce a balance.
Note 41, p. 241.--KITE MESSENGERS.
The curious experiments of Mr. Faraday upon the optical effects
produced by the revolutions of different wheels, might be exhibited by
arrangements adjusted as messengers.
Note 42, p. 246.--WINDS AND STORMS.
The sea and land breezes which occur in the islands of the torrid zone,
very strikingly illustrate the position laid down in the text, and
afford a good explanation of the manner in which winds may be
occasioned by a change of temperature in the air. In these, during the
hottest part of the day, the wind sets in from all quarters, and
appears to be blowing towards the centre of the island, while in the
night it changes its direction, and blows from the centre of the land
towards the sea; for since the sun’s rays produce much more heat by
their reflection from land than they do from water, that portion of air
which is over the land will soon become heated, and will ascend; a
rarefaction and diminution of the quantity of air over the central part
of the land will be thus occasioned, which must be supplied from the
sides; but, as the land cools again during the night, that portion of
air which had been previously heaped up will begin to descend, and by
spreading and equalizing itself will produce a breeze blowing from the
centre.
The _trade-winds_, so called from the advantage which their certainty
affords to trading vessels, are another example of the same kind; they
are generally stated to blow from east to west over the equator, and
are occasioned by the rarefaction of the air by the sun’s heat, and the
motion of the earth from west to east. While writing the present note,
we have seen an essay upon the subject by Captain Basil Hall, published
in an appendix to Mr. Daniel’s admirable work on Meteorology: the
perusal of this paper has induced us to cancel what we had written, and
to refer the reader to the essay itself; for it is quite impossible to
do justice to the views it entertains, in the limited space necessarily
prescribed to us in this note.
On the coast of Guinea, the wind always sets in upon the land, blowing
westerly instead of easterly; this exception arises from the deserts of
Africa, which lie near the equator, and being a very sandy soil,
reflect a great degree of heat into the air above them, which being
thus rendered lighter than that which is over the sea, the wind
continually rushes in upon the land to restore the equilibrium.
Among the irregular winds, or those which are not constant, but
accidental, may be noticed the _whirlwind_, the _harmattan_, and the
_sirocco_. The first of these is occasioned by the meeting of two or
more currents of wind from opposite directions, and which can only be
occasioned by some temporary but violent disturbance of equilibrium.
The _harmattan_ is met with on the western coast of Africa, and is
generally attended by great heat and fog; it appears to be occasioned
by a conflict between the heated sands of Africa, and the regular
direction of the trade-winds over that continent, and, by disturbing
their progress, it is frequently the forerunner of a hurricane in the
West Indies. The _sirocco_ occurs in Egypt, the Mediterranean, and in
Greece, and is chiefly characterised by its unhealthy qualities. The
air, by passing over the heated sands of Egypt, becomes so dried and
rarefied as to be scarcely fit for respiration, and, being thus
prepared, it absorbs so much humidity on passing the Mediterranean as
to form a suffocating and oppressive kind of fog.
Mr. Daniel observes, that the currents of a heated room, in some
measure, exemplify the great currents of the atmosphere. If the door be
opened, the flame of a candle held to the upper part will show, by its
inclination, a current flowing outwards; but, if held near the floor,
it will be directed inwards. If the door be closed suddenly from
without, it moves with the in-coming current, and against the
out-going, and a condensation of air takes place in the room; which is
proved by the rattling of the windows, and the bursting open of any
door in the room, if slightly closed. If the door close from within, it
moves against the in-coming current, and with the out-going, and a
rarefaction of the air in the room takes place; which is evidenced by
the rattling of the windows, and the bursting open of another door in
the contrary direction.
Meteorology has been long considered the least perfect branch of
natural knowledge; so apparently capricious and irregular are its
phenomena, that philosophers had almost abandoned the idea of bringing
them under the operation of any general laws. Brighter lights are,
however, now dawning upon us. Mr. Whewell, in his Bridgewater Treatise,
has explained the manner in which the various currents of the
atmosphere maintain a necessary balance in the distribution of heat and
moisture around the globe, and has thus reduced to order and design
phenomena which have hitherto been regarded as unconnected and
fortuitous. Lieut.-Col. Reid, by his late happy investigation of the
law of storms, will, no doubt, lead us into a novel path of the most
important discoveries. He has satisfactorily proved, by a mass of
evidence derived from numerous logbooks, that storms obey fixed laws.
His attention was ardently directed to the subject by having been at
Barbadoes immediately after the great hurricane of 1831, which in the
short space of seven hours killed upwards of 1400 persons on that
island alone. The discoveries of Col. Reid may be thus briefly
stated.--That hurricanes are whirlwinds of great diameter, always
revolving according to an invariable law, viz. from right to left
(supposing yourself standing in the centre), or in the opposite way to
the hands of a watch, in the northern hemisphere, and in a contrary
direction in southern latitudes; at the same time they have a
progressive motion in a curved line, and as they advance their
diameters appear to enlarge and their violence to diminish; it has been
also found that in the centre of the vortex there is a lull, or calm.
Col. Reid observes that the simplest mode of illustrating the subject
is to cut out concentric circles, so as to represent progressive
whirlwinds, by moving which over any tract, the veering of the wind
will be easily understood. The reader may form a more familiar idea by
causing the water to circulate in a basin, which will represent the
violent circular motion of the storm-wind, with a calm in the centre of
the vortex. Suppose this to be also moving onward at a rate of about
seven miles an hour, and he will have a correct notion of the subject.
Since the storms expand in size and diminish in force as they proceed
towards the poles, and the meridians at the same time approach each
other, gales become huddled together; and hence, apparently, the true
cause of the very complicated nature of the winds in our latitude.
Observations would also appear to render it probable that there exists
an accordance of the force of storms with the law of magnetic
intensity; for example, it is at its minimum at St. Helena, where
storms never occur; on the contrary, the lines of greatest intensity
seem to correspond with the latitudes of typhoons and hurricanes. To
what important discoveries may not the pursuit of this enquiry lead us?
The practical importance of the foregoing facts must be obvious: to use
the expression of Sir John Herschel, “they will teach seamen how to
steer their ships, and save thousands of lives.” They will thus learn
on which side to lay-to a ship in a storm, for, by watching the veering
of the wind, they will ascertain the direction in which it is falling;
if violent, and the changes sudden, the ship will probably be near the
centre of the vortex; whereas, if the wind blows a great length of time
from the same point, and the changes are gradual, it may reasonably be
supposed the ship is near the extremity of it. The barometer also
becomes a very important instrument upon these occasions; the rapid
rotatory motion of a column of the atmosphere necessarily occasions its
fall, and this fall is always greatest at the centre of the storm. When
it begins to rise, the centre has passed, and when the wind has
sufficiently abated to enable a ship to make sail, she may then bear
away with safety; but near the middle of the hurricane, before the
barometer begins to rise, all square-sails must be dangerous.
Note 43, p. 250.--ANCIENT ARCHERY.
We are reminded, upon this occasion, of part of a stanza in the
well-known ballad of Chevy Chace, where an English archer aimed his
arrow at Sir Hugh Montgomery:--
“The _grey goose wing_ that was thereon,
In his hearte’s blood was wett.”
The more ancient ballad, however, reads _swane-feathers_. In the “Geste
of Robyn Hode,” among Mr. Garrick’s old plays, in the Museum, the
arrows of the outlaw and his companions are particularly described:--
“With them they had an hundred bowes,
The strings were well ydight;
An hundred shefe of arrows good,
With hedes burnish’d full bryght;
And every arrowe an ell longe,
With _peacocke_ well ydight,
And rocked they were with white silk,
It was a semely sight.”
And Chaucer, in the description of the squyer’s yeoman, says:--
“And he was clad in cote and hode of greene;
A sheafe of _peacocke_ arrows bryght and shene,
Under his belt he bare full thriftely,
Well coude he dresse his tackle yemanly:
His arrowes drouped not with fethers lowe,
And in his hand he bare a mighty bowe.”
_Prol. to Cant. Tales._
In order to show the dandyism displayed by the archers of former times,
it may be stated, that, in the wardrobe accounts of the 28 Edw. I. p.
359, is a charge for verdigrise to stain the feathers of the arrows
green. A wardrobe account of the 4 Edw. II. furnishes an entry for
peacock arrows, “Pro duodecim flecchiis cum pennis de _pavone_, emptis
pro rege de 12 den.”
As this note has some connexion with the shuttlecock,[84] as well as
the arrow, we may take this opportunity of introducing a passage, which
was accidentally omitted in the text; it refers to the method of
playing this game at Turon, in Cochin China; and which is described by
a traveller as follows:--“Instead of using a battledoor,[85] as is the
custom in England, the players stood seven or eight in a circle; and
after running a short race, and springing from the floor, they met the
descending shuttlecock with the sole of the foot, and drove it up again
with force high in the air. The game was kept up with much animation,
and seldom did the players miss their stroke, or give it a wrong
direction. The shuttlecock was made of a piece of dried skin rolled
round, and bound with strings. Into this skin were inserted three
feathers, spreading out at top, but so near to each other, where they
were stuck into the skin, as to pass through the holes, little more
than a quarter of an inch square, which were always made in the centre
of Cochin copper coins. We made one or two awkward attempts at the
game, not only to our own confusion, but much to the amusement of the
natives. It must, however, be remembered, that, amongst these ingenious
people, the feet assist, as auxiliaries to the hands, in the exercise
of many trades, particularly that of boat-building.”
-----
Footnote 84:
Shuttlecock, more correctly, perhaps, shuttle-_cork_, although
Skinner thinks it is called a _cock_ from its feathers.
Footnote 85:
So called from door, taken for a flat board; and battle, for
striking, _i. e._ a striking-board.
-----
Note 44, p. 270.--SOUND CONVEYED BY SOLID BODIES.
A beautiful experiment was lately instituted at Paris, to illustrate
this fact, by Biot. At the extremity of a cylindrical tube, upwards of
3000 feet in length, a ring of metal was placed, of the same diameter
as the aperture of the tube; and in the centre of this ring, in the
mouth of the tube, was suspended a clock-bell and hammer. The hammer
was made to strike the ring and the bell at the same instant, so that
the sound of the ring would be transmitted to the remote end of the
tube through the conducting power of the matter of the tube itself;
while the sound of the bell would be transmitted through the medium of
the air included within the tube. The ear being then placed at the
remote end of the tube, the sound of the ring, transmitted by the metal
of the tube, was first distinctly heard; and, after a short interval
had elapsed, the sound of the bell, transmitted by the air in the tube,
was heard. The result of several experiments was, that the metal of the
tube conducted the sound with about ten and a half times the velocity
with which it was conducted by the air; that is, at the rate of about
11,865 feet per second.
Note 45, p. 288.--EXPRESSIVE MUSIC.
The biographer of Josquin des Prez, the celebrated musician, and
_maestro di capella_ to Louis XII. King of France, relates an anecdote
which may be here told in connexion with the present subject. When
Josquin was first admitted into the service of the French monarch, he
had been promised a benefice by his Majesty; but this Prince, contrary
to his usual habits, for he was in general both just and liberal,
forgot the promise he had made; when Josquin, after suffering great
inconvenience from the shortness of his Majesty’s memory, ventured by
the following expedient to remind him publicly of his promise without
giving offence. He had been commanded to compose a motet for the Chapel
Royal, on which occasion he selected part of the 119th Psalm, “_Memor
esto verbi tui servo tuo_”--“_Oh think of thy servant, as concerning
thy word_,” which he set in so supplicating and exquisite a manner,
that it was universally admired, particularly by the King, who was not
only touched by the music, but felt the words so effectually, that he
soon afterwards granted his petition, by conferring on him the promised
preferment. For which act of justice and munificence, Josquin, with
equal felicity, composed as a hymn of gratitude another part of the
same Psalm,--“_Bonitatem fecisti cum servo tuo, Domine_”--“_Oh Lord,
thou has dealt graciously with thy servant._”
Josquin, among musicians, was the giant of his time, and seems to have
arrived at universal monarchy and dominion over the affections and
passions of the musical part of mankind; indeed, his compositions were
as well known and as much practised throughout Europe at the beginning
of the sixteenth century, as those of Handel were in Europe sixty years
ago.
Note 46, p. 294.--IMAGINARY FORMS.
The following case, quoted by Sir David Brewster, in his work on
“Natural Magic,” from the life of Peter Heaman, a Swede, who was
executed for piracy and murder at Leith in 1822, will afford a very
curious example of the influence of the imagination in creating
distinct forms out of an irregularly shaded surface. “One remarkable
thing was, one day as we mended a sail, it being a very thin one, after
laying it upon deck in folds, I took the tar-brush and tarred it over
in the places which I thought needed to be strengthened. But when we
hoisted it up, I was astonished to see that the tar I had put upon it
represented a gallows and a man under it without a head. The head was
lying beside him. He was complete, body, thighs, legs, arms, and in
every shape like a man. Now, I oftentimes made remarks upon it, and
repeated them to the others. I always said to them all, ‘You may depend
upon it that something will happen.’ I afterwards took down the sail on
a calm day, and sewed a piece of canvass over the figure to cover it,
for I could not bear to have it always before my eyes.”
The curious effect of chance resemblance was particularly remarked by
Leonardo da Vinci in the moss and stains on old stones. And, in our own
times, this faculty of the imagination has not unfrequently been
enlisted into the service of the fortune-teller for purposes of fraud
and imposition. The following story is related on credible testimony.
“A British officer, in expectation of promotion, and of being united to
a lady in marriage, sought a gipsy fortune-teller. The sorceress, no
doubt, had made herself well acquainted with these circumstances. On
entering the room, she ordered a large glass of spring-water, into
which she poured the white of a newly-laid egg. After shaking the
mixture for some time, she so far succeeded as to induce the credulous
observer to declare that he saw most distinctly the image of the ship
in which he was to hoist his flag, the church in which he was to be
married, and his bride going with him into the church.”--_The Gipsies’
Advocate_, by J. Crabb.
Note 47, p. 295.--FAIRY RINGS.
Dr. Wollaston, in a paper published in the Philosophical Transactions,
(1807, p. 133,) relates some interesting observations he made on the
progressive changes of these rings, and which satisfactorily explain
their origin. He observed, that some species of fungi were always to be
found at the exterior margin of the dark ring of grass if examined at
the proper season. The position of the fungi led him to believe, that
progressive increase from a central point was the probable mode of
formation of the ring; and he thought it likely that the soil which had
once contributed to the support of fungi, might be so exhausted as to
be rendered incapable of producing a second crop. The defect of
nutriment on one side would occasion the new roots to extend themselves
solely in the opposite direction, and would cause the circle of fungi
continually to proceed, by annual enlargement, from the centre
outwards. The luxuriance of the grass follows as a natural consequence,
as the soil of an interior circle is enriched by the decayed roots of
fungi of the succeeding year’s growth. During the growth of fungi, they
so entirely absorb all nutriment from the soil beneath, that the
herbage is often for a while destroyed, and a ring appears bare of
grass, surrounding the dark ring; but, after the fungi have ceased to
appear, the soil where they had grown becomes darker, and the grass
soon vegetates again with peculiar vigour. Dr. Wollaston had many
opportunities of remarking, that, when two circles interfere with each
other’s progress, they do not cross each other, but are invariably
obliterated between the points of contact. The exhaustion occasioned by
each obstructs the progress of the other, and both are _starved_; a
circumstance which affords a strong confirmation of the above theory.
Note 48, p. 300.--RESONANCE.
In order to comprehend the nature of _reciprocated vibration_, or
_resonance_, let the reader keep in his remembrance the analogy between
musical vibration, and the oscillation of the pendulum, as explained at
page 275. If he well understands the phenomena of the latter, he will
readily comprehend those of the former. Galileo observed that a heavy
pendulum might be put in motion by the least breath of the mouth,
_provided the blasts were often repeated, and made to keep time exactly
with the vibrations of the pendulum_: from the same sympathetic
communication of vibrations will two pendulum clocks fixed to the same
wall, or two watches lying upon the same table, take the same rate of
going, though they would not agree with one another if placed in
separate apartments. Mr. Ellicot indeed observed that the pendulum of
one clock was even able to stop that of the other; and that the stopped
pendulum, after a certain time, would resume its vibrations, and in its
turn stop the vibrations of the other. We have here a correct
explanation of the phenomena of _Resonance_; for the undulations
excited by a vibratory body are themselves capable of putting in motion
all bodies whose pulses are coincident with their own, and consequently
with those of the primitive sounding body; hence the vibrations of a
string, when another, tuned in unison with it, is made to vibrate.
Upon the same principle does the resonance, or reciprocated vibrations
of columns of air, depend. We are much indebted to Mr. Wheatstone for
our knowledge of this branch of acoustics; he has shown that, if a
tuning-fork or a bell be sounded before a tube inclosing a column of
air of the necessary length, the original sound will be augmented by
the rich resonance of that air; and that the sounds of tuning-forks, if
held before the cavity of the mouth, may be reciprocated most intensely
by adjusting the alterable volume of air contained within it to the
pitch of the instrument; by placing, for instance, the tongue, &c. in
the position for the nasal continuous sound of _ng_ (in song), and then
altering the aperture of the lips, until the loudest sound was
obtained, he readily accomplished his object.
If two vibrating tuning-forks, differing in pitch, be held over a
closed tube, furnished with a moveable piston, either sound may be made
to predominate, by so altering the piston as to obtain the exact column
of air which will reciprocate the required sound. The same result may
be obtained by selecting two bottles (which may be tuned with water)
each corresponding to the sound of a different tuning fork; on bringing
both tuning-forks to the mouth of each bottle alternately, that sound
only will be heard, in each case, which is reciprocated by the
unisonant bottle; or, in other words, by that bottle which contains a
column of air susceptible of vibrating in unison with the fork.
Among the Javanese instruments brought to England by the late Sir
Stamford Raffles, there is one called the _gender_, in which the
resonances of columns of air are employed to augment, we might almost
say to render audible, the sounds of vibrating metallic plates. Under
each of these plates is placed an upright bamboo, containing a column
of air of the proper length to reciprocate the lowest sound of such
plate. If the aperture of the bamboo be covered with pasteboard, and
its corresponding plate be struck, a number of acute sounds only
(depending on the more numerous subdivisions of the plate) will be
heard; but, on removing the pasteboard, an additional deep rich tone is
produced by the resonance of the column of air within the tube.
It is only by a knowledge of this principle that the theory of the
Guimbarde, or Jew’s harp, can be well understood.
Note 49, p. 300.--THE JEW’S HARP.
The Memoires of Madame de Genlis first made known the astonishing
powers of a poor German soldier on the Jew’s harp. This musician was in
the service of Frederick the Great, and finding himself one night on
duty under the windows of the king, played the Jew’s harp with so much
skill, that Frederick, who was a great amateur of music, thought he
heard a distinct orchestra. Surprised on learning that such an effect
could be produced by a single man with two Jew’s harps, he ordered him
into his presence; the soldier refused, alleging that he could only be
relieved by his colonel; and that, if he obeyed, the king would punish
him the next day for having failed to do his duty. Being presented the
following morning to Frederick, he was heard with admiration, and
received his discharge and fifty dollars. This artist, whose name
Madame de Genlis does not mention, is called Koch; he has not any
knowledge of music, but owes his success entirely to a natural taste.
He has made his fortune by travelling about, and performing in public
and private; and is now living retired at Vienna, at the advanced age
of more than eighty years. He used two Jew’s harps at once, in the same
manner as the peasants of the Tyrol; and produced, without doubt, the
harmony of two notes struck at the same moment, which was considered by
the musically-curious as somewhat extraordinary, when the limited
powers of the instrument were remembered. It was Koch’s custom to
require that all the lights should be extinguished, in order that the
illusion produced by his playing might be increased.
It was reserved, however, for Mr. Eulenstein to acquire a musical
reputation from the Jew’s harp. After ten years of close application
and study, this young artist has attained a perfect mastery over this
untractable instrument. In giving some account of the Jew’s harp,
considered as a medium for musical sounds, we shall only present the
result of his discoveries. This little instrument, taken singly, gives
whatever grave sound you may wish to produce, as a _third_, a _fifth_,
or an _octave_. If the grave tonic is not heard in the bass Jew’s harp,
it must be attributed not to the defectiveness of the instrument, but
to the player. In examining this result, you cannot help remarking the
order and unity established by nature in harmonical bodies, which
places music in the rank of exact sciences. The Jew’s harp has three
different tones; the bass tones of the first octave bear some
resemblance to those of the flute and clarionet; those of the middle
and high to the _vox humana_ of some organs; lastly, the harmonical
sounds are exactly like those of the _harmonica_. It is conceived that
this diversity of tones affords already a great variety in the
execution, which is always looked upon as being feeble and trifling, on
account of the smallness of the instrument. It was not thought possible
to derive much pleasure from any attempt which could be made to conquer
the difficulties of so limited an instrument; because, in the extent of
these octaves, there were a number of spaces which could not be filled
up by the talent of the player; besides, the most simple modulation
became impossible. Mr. Eulenstein has remedied that inconvenience, by
joining sixteen Jew’s harps, which he tunes by placing smaller or
greater quantities of sealing-wax at the extremity of the tongue. Each
harp then sounds one of the notes of the gamut, diatonic or chromatic;
and the performer can fill all the intervals, and pass all the tones,
by changing the harp. That these mutations may not interrupt the
measure, one harp must always be kept in advance, in the same manner as
a good reader advances the eye, not upon the word which he pronounces,
but upon that which follows.
Note 50, p. 316.--VERBAL TELEGRAPH.
This project has lately been revived; in a late number of the _Revue
Encyclopédique_ there is a proposal to communicate verbal intelligence,
in a few moments, to vast distances; and this not by symbols, as in the
Telegraph, but in distinct articulate sounds uttered by the human
voice. The plan is said to have originated with an Englishman, Mr.
Dick, according to whose experiments the human voice may be made
intelligible at the distance of twenty-five or thirty miles. It has
been stated, in Note 44, that the celebrated Biot had ascertained that
sound travels more than ten times quicker when transmitted by solid
bodies, or through tubes, than when it passes through the open air; at
the distance of more than half a mile the low voice of a man was
distinctly heard. Father Kircher relates in some of his works, that the
labourers employed in the subterranean aqueducts of Rome heard each
other at the distance of several miles. The note which follows was
published in the early edition of this work, before the subject
attracted any notice, or any railroad had been completed. It is
therefore reprinted without alteration.
Note 51, p. 316.--ELECTRICAL TELEGRAPH.
It has often occurred to the author of these pages, during his
reveries, that the means of conveying intelligence with immense
rapidity may be hereafter invented by the Electrician.--Should a system
of railways be established throughout the country, it might lead to
some expedient by which such a desideratum could be accomplished
through the medium of electrical discharges. Upon this subject we have
accidentally fallen upon a curious notice in Arthur Young’s Travels in
France (vol. i. p. 65). “M. Lomond has made a very curious discovery in
electricity; you write two or three words on a paper, he takes it with
him into his room, and there turns a machine inclosed in a cylindrical
case, at the top of which is an electrometer of pith balls; by means of
a wire, a connexion is made with a similar cylinder and electrometer in
a distant apartment, and his wife, by remarking the corresponding
motions of the balls, writes down the words they indicate; from which
it appears that he has formed an _Alphabet of Motion_. As the length of
the conducting wire makes no difference in the effect, a correspondence
might be carried on at any distance, as, for example, within or without
a besieged town; or for purposes much more interesting and useful.
Whatever the uses may be, the invention is beautiful.”
Note 52, p. 368.--CARRIER PIGEONS.
The _carrier_ is a variety of the common domestic pigeon, and which,
from the superior attachment that it shows to its native place, is
employed in many countries as the most expeditious courier. The letters
are tied under its wing, it is let loose, and in a very short space
returns to the home it was brought from, with its advices. This
practice was much in vogue in the East; and at Scanderoon, till of late
years, it was used on the arrival of a ship, to give the merchants at
Aleppo a more expeditious notice than could be done by any other means.
In our own country, these aerial messengers have been employed for a
very singular purpose, having been let loose at Tyburn at the moment
the fatal cart was drawn away, to notify to distant friends the
departure of the unhappy criminal.
In the East, the use of these birds seems to have been greatly
improved, by having, if we may use the expression, relays of them ready
to spread intelligence to all parts of the country; thus it is stated
by Ariosto (canto 15), that the governor of Damiata circulated the news
of the death of Orrilo. “As soon as the commandant of Damiata heard
that Orrilo was dead, he let loose a pigeon, under whose wing he had
tied a letter. This fled to Cairo, from whence a second was despatched
to another place, as is usual; so that, in a very few hours, all Egypt
was acquainted with the death of Orrilo.”
But the simple use of them was known in very early times. Anacreon
tells us (ode ix.) that he conveyed his billet-doux to Bathyllus by a
dove.
Taurosthenes also, by means of a pigeon he had decked with purple, sent
advice to his father, who lived in the isle of Ægina, of his victory in
the olympic games, on the very day he had obtained it.[86] And, at the
siege of Modena, Hirtius without, and Brutus within the walls, kept, by
the help of pigeons, a constant correspondence; baffling every
stratagem of the besieger, Antony, to intercept their couriers. In the
times of the crusades, there are many more instances of these birds of
peace being employed in the service of war: Joinville relates one
during the crusade of _Saint Louis_, and Tasso another, during the
siege of Jerusalem.--_Pennant’s British Zoology._
The Dutch variety is the most valuable; a pair of the best kind being
worth from five to eight pounds. It is lighter than the English pigeon,
and flies nearly as fast again. It proceeds at the rate of 60 miles an
hour, and has been known to complete a journey of 800 miles, but this;
it is presumed, is not continuous, but assisted by occasional rest. The
bird learns but one lesson; it may carry from Antwerp to London, or to
any other place, but it will only pass between two such places. It
evidently travels by sight; when tossed, it circles, then rises in a
spiral, observes its route and darts off. It will not fly at night;
and, should the day be foggy, it is delayed, and sometimes lost.
Footnote 86:
_Ælian. Var. Hist._ lib. ix. c. 2. Pliny, lib. x. c. 24, says that
swallows have been made use of for the same purpose. Their rate of
flight has been estimated at a mile in a minute, for ten hours, or
600 miles per day.
Note 53, p. 371.--ORIGIN OF POPULAR CEREMONIES.
The soothsayers attributed many mystic properties to the coral; and it
was believed to be capable of giving protection against the influence
of _Evil Eyes_: it was even supposed that coral would drive away devils
and evil spirits; hence arose the custom of wearing amulets composed of
it around the neck, and of making crowns of it. Pliny and Dioscorides
are very loud in the praises of the medicinal properties of this
substance; and Paracelsus says that it should be worn round the necks
of infants, as an admirable preservative against fits, sorcery, charms,
and even against poison. It is a curious circumstance that the same
superstitious belief should exist among the negroes of the West Indies,
who affirm that the colour of coral is always affected by the state of
health of the wearer, it becoming paler in disease. In Sicily it is
also commonly worn as an amulet by persons of all ranks; as a security
against an _evil eye_, a small twisted piece, somewhat resembling a
horn, is worn at the watch-chain, under the name of _Buon Fortuna_, and
is occasionally pointed at those who are supposed to entertain evil
intention. His late Sicilian Majesty was celebrated for his faith in,
and frequent use of, the _buon fortuna_.--But to return to the coral
usually suspended around the necks of children in our own country. In
addition to the supposed virtues of the coral, it may be remarked that
silver bells are usually attached to it, which are generally regarded
as mere accompaniments to amuse the child by their jingle; but the fact
is, that they have a different origin, having been designed to frighten
away evil spirits. For the same superstitious objects were bells
introduced into our churches as a species of charm against storms and
thunder, and the assaults of Satan.
In farther illustration of the truth, that a custom has frequently
survived the tradition of its origin, it may be here observed, that the
common practice of persons who are unable to write, making their mark
or _cross_, is derived from our Saxon ancestors, who affixed the sign
of the cross, as a signature to a deed, whether they could write or
not. Several charters still remain, to which kings and persons of great
eminence affix “_Signum Crucis manu propriá pro ignorantiá literarum_.”
Hence is derived the expression of _signing_ instead of _subscribing_ a
paper. In like manner, the physician of the present day continues to
prefix to his prescriptions the letter R, which is generally supposed
to mean _Recipe_, but which, in truth, is a relict of the astrological
symbol of Jupiter, formerly used as a species of superstitious
invocation.
Note 54, p. 379.--INVENTION OF THE GAME OF CHESS.
Alphesadi, an Arabian writer, quoted by Montucla in his _Histoire des
Mathematiques_, expressly mentions the invention of chess as of
Indian origin, and relates the following very curious Indian
tradition:--Ardschir, King of the Persians, having invented the game
of _Tric-Trac_, and being exceedingly vain of it, a certain Indian,
named Sessa, the son of Daher, invented the game of chess, and
presented his chess-board and chess-men to the king of the Indies.
The sovereign was so much pleased, that he desired Sessa to name his
reward, when this man made the apparently modest request, that he
should receive as a gift so much corn as could be estimated by
beginning with one grain, and doubling as many times as there were
squares upon the chess-board, viz. 64. The king felt displeased at
having his munificence thus slighted by a request so limited and so
unworthy to be a gift from royalty; but, as Sessa remained firm,
orders were given to the chief minister that he should be satisfied:
when, however, the visir had by calculation ascertained the enormous
quantity of corn which would be required, he waited upon the king,
and with some difficulty convinced him of the fact; upon which the
king sent for Sessa,--and said to him, that he admired his powers of
calculation even more than the ingenuity of the game which he had
presented to him, and, in respect to his promise as to the corn, he
was compelled to acknowledge himself to be insolvent.
Dr. Wallis, the friend of Sir Isaac Newton, and Savilian Professor of
Oxford, found that the quantity of corn would be such as to be capable
of forming a pyramid, the measurement of which would be nine English
miles in height, and nine similar miles for each of the four sides of
the base. After this, Montucla also states some elaborate calculations
made by himself, and proves, amongst other remarkable facts, that the
quantity of corn in question would cover 162,000 square leagues to the
depth of one foot, French measure, which would be at least three times
the extent of the surface of France as it was about the year 1796, and
which he estimates at 50,000 square leagues.
Note 55, p. 388.--AN ARITHMETICAL TRICK.
This problem is to be found in Hutton’s Recreations, and is stated as
follows:--
“A person having in one hand an _even_ number of shillings, and in the
other an _odd_, to tell in which hand he has the even number.”
“Desire the person to multiply the number in the right hand by any even
number whatever, and that in the left by any odd number; then bid him
to add together the two products, and if the whole sum be odd, the even
number of shillings will be in the right hand, and the odd number in
the left; if the sum be even, the contrary will be the case. By a
similar process, a person having in one hand a piece of gold, and in
the other a piece of silver, we can tell in which hand he holds the
gold, and in which the silver. For this purpose, some value represented
by an even number, such as 8, must be assigned to the gold, and a value
represented by an odd number, such as 3, must be assigned to the
silver; after which the operation is exactly the same as in the
preceding example.
“To conceal the artifice better, it will be sufficient to ask whether
the sum of the two products can be halved without a remainder; for, in
that case, the total will be even, and in the contrary case odd.
“It will be readily seen that the pieces, instead of being in the two
hands of the same person, may be supposed to be in the hands of two
persons, one of whom has the even number, or piece of gold, and the
other the odd number, or piece of silver. The same operations may then
be performed in regard to these two persons, as are performed in regard
to the two hands of the same person, calling the one, privately, the
right, and the other the left.”
Note 56, p. 389.--AN ALGEBRAIC PROBLEM.
It is by discovering the number of counters left on the board that this
trick is performed. By means of a table the problem may be immediately
solved; but as such a reference would be inconvenient, and, indeed,
destructive to the magic of the trick, a Latin verse is substituted,
which may be easily carried in the memory, and will be found to answer
all the purposes of a table. In order, however, that the reader may
become thoroughly acquainted with the machinery of the trick, we shall
explain it in the words of its author. The problem is stated as
follows: “_Three things being privately distributed to three persons,
to guess that which each has got._”
Let the three things be a ring, a shilling, and a glove. Call the ring
A, the shilling E, and the glove I; and in your own mind distinguish
the persons by calling them first, second, and third. Then take
twenty-four counters, and give one of them to the first person, two to
the second, and three to the third. Place the remaining eighteen on the
table, and then retire, that the three persons may distribute among
themselves the three things proposed without your observing them. When
the distribution has been made, desire the person who has the ring to
take from the remaining eighteen counters as many as he has already;
the one who has the shilling to take twice as many as he has already,
and the person who has the glove to take four times as many; according
to the above supposition then, the first person has taken one, the
second four, and the third twelve; consequently, one counter only
remains on the table. When this is done, you may return, and, by the
number left, can discover what thing each person has taken, by
employing the following words:----
1 2 3 5 6 7
_Salve_ _certa_ _animæ_ _semita_ _vita_ _quies._
To make use of these words, you must recollect, that in all cases there
can remain only 1, 2, 3, 5, 6, or 7 counters, and never 4. It must
likewise be observed, that each syllable contains one of the vowels,
which we have made to represent the things proposed, and that the first
syllable of each word must be considered as representing the first
person, and the second syllable the second. This being comprehended, if
there remains only one counter, you must employ the first word, or
rather the two first syllables, _sal-ve_, the first of which, that
containing A, shows that the first person has the ring represented by
A; and the second syllable, that containing E, shows that the second
person has the shilling represented by E; from which you may easily
conclude that the third person has the glove. If two counters should
remain, you must take the second word _cer-ta_, the first syllable of
which, containing E, will show that the first person has the shilling
represented by E; and the second syllable, containing A, will indicate
that the second person has the ring represented by A. In general,
whatever number of counters remain, that word of the verse which is
pointed out by the same number must be employed.
Instead of the above Latin verse, the following French one might be
used:--
1 2 3 5 6 7
_Par fer_ _César_ _jadis_ _devint_ _si grand_ _prince._
In using the above line, it must be considered as consisting only of
six words.
This problem might be proposed in a manner somewhat different, and
might be applied to more than three persons. Those of our readers who
may be desirous of further information on the subject, must consult
Bachet in the 25th of his _Problèmes plaisantes et délectables_.
THE END.
Transcriber’s Notes
In order to get illustrations close to long descriptions and
discussions of them, a few long paragraphs have been divided in two at
logical places.
One obvious typographical error in punctuation was corrected.
All footnotes have been relocated at the ends of chapters.
Descriptive captions have been added to the text version for many
illustrations by the Transcribers and are deemed by them to be in the
public domain.
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