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[Illustration: (cover)]
_The Century Science Series_
Edited by Sir Henry E. Roscoe, D.C.L., LL.D., F.R.S.
JAMES CLERK MAXWELL AND MODERN PHYSICS
* * * * * *
The Century Science Series.
EDITED BY
SIR HENRY E. ROSCOE, D.C.L., F.R.S., M.P.
John Dalton and the Rise of Modern Chemistry.
By Sir HENRY E. ROSCOE, F.R.S.
Major Rennell, F.R.S., and the Rise of English Geography.
By CLEMENTS R. MARKHAM, C.B., F.R.S., President of the Royal
Geographical Society.
Justus von Liebig: his Life and Work (1803–1873).
By W. A. SHENSTONE, F.I.C., Lecturer on Chemistry in Clifton
College.
The Herschels and Modern Astronomy.
By AGNES M. CLERKE, Author of “A Popular History of Astronomy
during the 19th Century,” &c.
Charles Lyell and Modern Geology.
By Rev. Professor T. G. BONNEY, F.R.S.
James Clerk Maxwell and Modern Physics.
By R. T. GLAZEBROOK, F.R.S., Fellow of Trinity College,
Cambridge.
_In Preparation._
Michael Faraday: his Life and Work.
By Professor SILVANUS P. THOMPSON, F.R.S.
Humphry Davy.
By T. E. THORPE, F.R.S., Principal Chemist of the Government
Laboratories.
Pasteur: his Life and Work.
By M. ARMAND RUFFER, M.D., Director of the British Institute of
Preventive Medicine.
Charles Darwin and the Origin of Species.
By EDWARD B. POULTON, M.A., F.R.S., Hope Professor of Zoology
in the University of Oxford.
Hermann von Helmholtz.
By A. W. RÜCKER, F.R.S., Professor of Physics in the Royal
College of Science, London.
CASSELL & COMPANY, LIMITED, _London_; _Paris_ & _Melbourne_.
* * * * * *
[Illustration: J. Clerk Maxwell
(_From a Photograph of the Picture by G. Lowes Dickinson, Esq., in the
Hall of Trinity College, Cambridge._)]
The Century Science Series
JAMES CLERK MAXWELL AND MODERN PHYSICS
by
R. T. GLAZEBROOK, F.R.S.
Fellow of Trinity College, Cambridge
University Lecturer in Mathematics, and Assistant Director of the
Cavendish Laboratory
Cassell and Company, Limited
London, Paris & Melbourne
1896
All Rights Reserved
[Illustration]
PREFACE.
The task of giving some account of Maxwell’s work--of describing the
share that he has taken in the advance of Physical Science during the
latter half of this nineteenth century--has proved no light labour.
The problems which he attacked are of such magnitude and complexity,
that the attempt to explain them and their importance, satisfactorily,
without the aid of symbols, is almost foredoomed to failure. However,
the attempt has been made, in the belief that there are many who,
though they cannot follow the mathematical analysis of Maxwell’s work,
have sufficient general knowledge of physical ideas and principles to
make an account of Maxwell and of the development of the truths that he
discovered, subjects of intelligent interest.
Maxwell’s life was written in 1882 by two of those who were most
intimately connected with him, Professor Lewis Campbell and Dr.
Garnett. Many of the biographical details of the earlier part of this
book are taken from their work. My thanks are due to them and to their
publishers, Messrs. Macmillan, for permission to use any of the letters
which appear in their biography. I trust that my brief account may
be sufficient to induce many to read Professor Campbell’s “Life and
Letters,” with a view of learning more of the inner thoughts of one who
has left so strong an imprint on all he undertook, and was so deeply
loved by all who knew him.
R. T. G.
_Cambridge,
December, 1895._
CONTENTS.
CHAPTER PAGE
I. EARLY LIFE 9
II. UNDERGRADUATE LIFE AT CAMBRIDGE 28
III. EARLY RESEARCHES--PROFESSOR AT ABERDEEN 38
IV. PROFESSOR AT KING’S COLLEGE, LONDON--LIFE AT GLENLAIR 54
V. CAMBRIDGE--PROFESSOR OR PHYSICS 60
VI. CAMBRIDGE--THE CAVENDISH LABORATORY 73
VII. SCIENTIFIC WORK--COLOUR VISION 93
VIII. SCIENTIFIC WORK--MOLECULAR THEORY 108
IX. SCIENTIFIC WORK--ELECTRICAL THEORIES 148
X. DEVELOPMENT OF MAXWELL’S THEORY 202
JAMES CLERK MAXWELL
AND MODERN PHYSICS.
CHAPTER I.
EARLY LIFE.
“One who has enriched the inheritance left by Newton and has
consolidated the work of Faraday--one who impelled the mind of
Cambridge to a fresh course of real investigation--has clearly earned
his place in human memory.” It was thus that Professor Lewis Campbell
and Mr. Garnett began in 1882 their life of James Clerk Maxwell. The
years which have passed, since that date, have all tended to strengthen
the belief in the greatness of Maxwell’s work and in the fertility
of his genius, which has inspired the labours of those who, not in
Cambridge only, but throughout the world, have aided in developing the
seeds sown by him. My object in the following pages will be to give
some very brief account of his life and writings, in a form which may,
I hope, enable many to realise what Physical Science owes to one who
was to me a most kind friend as well as a revered master.
The Clerks of Penicuik, from whom Clerk Maxwell was descended, were
a distinguished family. Sir John Clerk, the great-great-grandfather
of Clerk Maxwell, was a Baron of the Exchequer in Scotland from
1707 to 1755; he was also one of the Commissioners of the Union,
and was in many ways an accomplished scholar. His second son George
married a first cousin, Dorothea Maxwell, the heiress of Middlebie in
Dumfriesshire, and took the name of Maxwell. By the death of his elder
brother James in 1782 George Clerk Maxwell succeeded to the baronetcy
and the property of Penicuik. Before this time he had become involved
in mining and manufacturing speculations, and most of the Middlebie
property had been sold to pay his debts.
The property of Sir George Clerk Maxwell descended in 1798 to his two
grandsons, Sir George Clerk and Mr. John Clerk Maxwell. It had been
arranged that the younger of the two was to take the remains of the
Middlebie property and to assume with it the name of Maxwell. Sir
George Clerk was member for Midlothian, and held office under Sir
Robert Peel. John Clerk Maxwell was the father of James Clerk Maxwell,
the subject of this sketch.[1]
John Clerk Maxwell lived with his widowed mother in Edinburgh until her
death in 1824. He was a lawyer, and from time to time did some little
business in the courts. At the same time he maintained an interest in
scientific pursuits, especially those of a practical nature. Professor
Campbell tells us of an endeavour to devise a bellows which would give
a continuous draught of air. In 1831 he contributed to the _Edinburgh
Medical and Philosophical Journal_ a paper entitled “Outlines of a Plan
for combining Machinery with the Manual Printing Press.”
In 1826 John Clerk Maxwell married Miss Frances Cay, of North Charlton,
Northumberland. For the first few years of their married life their
home was in Edinburgh. The old estate of Middlebie had been greatly
reduced in extent, and there was not a house on it in which the laird
could live. However, soon after his marriage, John Clerk Maxwell
purchased the adjoining property of Glenlair and built a mansion-house
for himself and his wife. Mr. Maxwell superintended the building work.
The actual working plans for some further additions made in 1843
were his handiwork. A garden was laid out and planted, and a dreary
stony waste was converted into a pleasant home. For some years after
he settled at Glenlair the house in Edinburgh was retained by Mr.
Maxwell, and here, on June 13, 1831, was born his only son, James Clerk
Maxwell. A daughter, born earlier, died in infancy. Glenlair, however,
was his parents’ home, and nearly all the reminiscences we have of
his childhood are connected with it. The laird devoted himself to his
estates and to the education of his son, taking, however, from time to
time his full share in such county business as fell to him. Glenlair in
1830 was very much in the wilds; the journey from Edinburgh occupied
two days. “Carriages in the modern sense were hardly known to the Vale
of Urr. A sort of double gig with a hood was the best apology for a
travelling coach, and the most active mode of locomotion was in a kind
of rough dog-cart known in the family speech as a hurly.”[2]
Mrs. Maxwell writes thus[3], when the boy was nearly three years old,
to her sister, Miss Jane Cay:--
“He is a very happy man, and has improved much since the
weather got moderate. He has great work with doors, locks,
keys, etc., and ‘Show me how it doos’ is never out of his
mouth. He also investigates the hidden course of streams and
bell-wires--the way the water gets from the pond through the
wall and a pend or small bridge and down a drain into Water
Orr, then past the smiddy and down to the sea, where Maggy’s
ships sail. As to the bells, they will not rust; he stands
sentry in the kitchen and Mag runs through the house ringing
them all by turns, or he rings and sends Bessy to see and shout
to let him know; and he drags papa all over to show him the
holes where the wires go through.”
To discover “how it doos” was thus early his aim. His cousin, Mrs.
Blackburn, tells us that throughout his childhood his constant question
was, “What’s the go of that? What does it do?” And if the answer were
too vague or inconclusive, he would add, “But what’s the _particular_
go of that?”
Professor Campbell’s most interesting account of these early years is
illustrated by a number of sketches of episodes in his life. In one
Maxwell is absorbed in watching the fiddler at a country dance; in
another he is teaching his dog some tricks; in a third he is helping a
smaller boy in his efforts to build a castle. Together with his cousin,
Miss Wedderburn, he devised a number of figures for a toy known as a
magic disc, which afterwards developed into the zoetrope or wheel of
life, and in which, by means of an ingenious contrivance of mirrors,
the impression of a continuous movement was produced.
This happy life went on until his mother’s death in December, 1839; she
died, at the age of forty-eight, of the painful disease to which her
son afterwards succumbed. When James, being then eight years old, was
told that she was now in heaven, he said: “Oh, I’m so glad! Now she’ll
have no more pain.”
After this his aunt, Miss Jane Cay, took a mother’s place. The problem
of his education had to be faced, and the first attempts were not
successful. A tutor had been engaged during Mrs. Maxwell’s last
illness, and he, it seems, tried to coerce Clerk Maxwell into learning;
but such treatment failed, and in 1841, when ten years old, he began
his school-life at the Edinburgh Academy.
School-life at first had its hardships. Maxwell’s appearance, his
first day at school, in Galloway home-spun and square-toed shoes with
buckles, was more than his fellows could stand. “Who made those shoes?”
they asked[4]; and the reply they received was--
“Div ye ken ’twas a man,
And he lived in a house,
In whilk was a mouse.”
He returned to Heriot Row that afternoon, says Professor Campbell,
“with his tunic in rags and wanting the skirt, his neat frill rumpled
and torn--himself excessively amused by his experiences and showing not
the slightest sign of irritation.”
No. 31, Heriot Row, was the house of his widowed aunt, Mrs. Wedderburn,
Mr. Maxwell’s sister; and this, with occasional intervals when he
was with Miss Cay, was his home for the next eight or nine years.
Mr. Maxwell himself, during this period, spent much of his time in
Edinburgh, living with his sister during most of the winter and
returning to Glenlair for the spring and summer.
Much of what we know of Clerk Maxwell’s life during this period comes
from the letters which passed between him and his father. They tell
us of the close intimacy and affection which existed between the two,
of the boy’s eager desire to please and amuse his father in the dull
solitude of Glenlair, and his father’s anxiety for his welfare and
progress.
Professor Campbell was his schoolfellow, and records events of those
years in which he shared, which bring clearly before us what Clerk
Maxwell was like. Thus he writes[5]:--
“He came to know Swift and Dryden, and after a while Hobbes,
and Butler’s ‘Hudibras.’ Then, if his father was in Edinburgh,
they walked together, especially on the Saturday half-holiday,
and ‘viewed’ Leith Fort, or the preparations for the Granton
railway, or the stratification of Salisbury Crags--always
learning something new, and winning ideas for imagination to
feed upon. One Saturday, February 12, 1842, he had a special
treat, being taken ‘to see electro-magnetic machines.’”
And again, speaking of his school-life:--
“But at school also he gradually made his way. He soon
discovered that Latin was worth learning, and the Greek
Delectus interested him when we got so far. And there were two
subjects in which he at once took the foremost place, when he
had a fair chance of doing so; these were Scripture Biography
and English. In arithmetic as well as in Latin his comparative
want of readiness kept him down.
“On the whole he attained a measure of success which helped
to secure for him a certain respect; and, however strange he
sometimes seemed to his companions, he had three qualities
which they could not fail to understand--agile strength
of limb, imperturbable courage, and profound good-nature.
Professor James Muirhead remembers him as ‘a friendly boy,
though never quite amalgamating with the rest.’ And another old
class-fellow, the Rev. W. Macfarlane of Lenzie, records the
following as his impression:--‘Clerk Maxwell, when he entered
the Academy, was somewhat rustic and somewhat eccentric. Boys
called him “Dafty,” and used to try to make fun of him. On one
occasion I remember he turned with tremendous vigour, with a
kind of demonic force, on his tormentors. I think he was let
alone after that, and gradually won the respect even of the
most thoughtless of his schoolfellows.’”
The first reference to mathematical studies occurs, says Professor
Campbell, in a letter to his father written soon after his thirteenth
birthday.[6]
“After describing the Virginian Minstrels, and betwixt
inquiries after various pets at Glenlair, he remarks, as if it
were an ordinary piece of news, ‘I have made a tetrahedron, a
dodecahedron, and two other hedrons, whose names I don’t know.’
We had not yet begun geometry, and he had certainly not at this
time learnt the definitions in Euclid; yet he had not merely
realised the nature of the five regular solids sufficiently to
construct them out of pasteboard with approximate accuracy, but
had further contrived other symmetrical polyhedra derived from
them, specimens of which (as improved in 1848) may be still
seen at the Cavendish Laboratory.
“Who first called his attention to the pyramid, cube, etc., I
do not know. He may have seen an account of them by chance in a
book. But the fact remains that at this early time his fancy,
like that of the old Greek geometers, was arrested by these
types of complete symmetry; and his imagination so thoroughly
mastered them that he proceeded to make them with his own
hand. That he himself attached more importance to this moment
than the letter indicates is proved by the care with which he
has preserved these perishable things, so that they (or those
which replaced them in 1848) are still in existence after
thirty-seven years.”
The summer holidays were spent at Glenlair. His cousin, Miss Jemima
Wedderburn, was with him, and shared his play. Her skilled pencil
has left us many amusing pictures of the time, some of which are
reproduced by Professor Campbell. There were expeditions and picnics of
all sorts, and a new toy known as “the devil on two sticks” afforded
infinite amusement. The winter holidays usually found him at Penicuik,
or occasionally at Glasgow, with Professor Blackburne or Professor
W. Thomson (now Lord Kelvin). In October, 1844, Maxwell was promoted
to the rector’s class-room. John Williams, afterwards Archdeacon of
Cardigan, a distinguished Baliol man, was rector, and the change was
in many ways an important one for Maxwell. He writes to his father: “I
like P---- better than B----. We have lots of jokes, and he speaks a
great deal, and we have not so much monotonous parsing. In the English
Milton is better than the History of Greece....”
P---- was the boys’ nickname for the rector; B---- for Mr. Carmichael,
the second master. This[7] is the account of Maxwell’s first interview
with the rector:--
_Rector_: “What part of Galloway do you come from?”
_J. C. M._: “From the Vale of Urr. Ye spell it o, err, err, or oo, err,
err.”
The study of geometry was begun, and in the mathematical master, Mr.
Gloag, Maxwell found a teacher with a real gift for his task. It was
here that Maxwell’s vast superiority to many who were his companions
at once showed itself. “He seemed,” says Professor Campbell, “to be in
the heart of the subject when they were only at the boundary; but the
boyish game of contesting point by point with such a mind was a most
wholesome stimulus, so that the mere exercise of faculty was a pure
joy. With Maxwell the first lessons of geometry branched out at once
into inquiries which became fruitful.”
In July, 1845, he writes:--
“I have got the 11th prize for Scholarship, the 1st for
English, the prize for English verses, and the Mathematical
Medal. I tried for Scripture knowledge, and Hamilton in the 7th
has got it. We tried for the Medal on Thursday. I had done them
all, and got home at half-past two; but Campbell stayed till
four. I was rather tired with writing exercises from nine till
half-past two.
“Campbell and I went ‘once more unto the b(r)each’ to-day at
Portobello. I can swim a little now. Campbell has got 6 prizes.
He got a letter written too soon, congratulating him upon _my_
medal; but there is no rivalry betwixt us, as B---- Carmichael
says.”
After a summer spent chiefly at Glenlair, he returned with his father
to Edinburgh for the winter, and began, at the age of fourteen, to go
to the meetings of the Royal Society of Edinburgh. At the Society of
Arts he met Mr. R. D. Hay, the decorative painter, who had interested
himself in the attempt to reduce beauty in form and colour to
mathematical principles. Clerk Maxwell was interested in the question
how to draw a perfect oval, and devised a method of drawing oval curves
which was referred by his father to Professor Forbes for his criticism
and suggestions. After discussing the matter with Professor Kelland,
Professor Forbes wrote as follows[8]:--
“MY DEAR SIR,--I am glad to find to-day, from Professor
Kelland, that his opinion of your son’s paper agrees with
mine, namely, that it is most ingenious, most creditable to
him, and, we believe, a new way of considering higher curves
with reference to foci. Unfortunately, these ovals appear
to be curves of a very high and intractable order, so that
possibly the elegant method of description may not lead to a
corresponding simplicity in investigating their properties. But
that is not the present point. If you wish it, I think that
the simplicity and elegance of the method would entitle it to
be brought before the Royal Society.--Believe me, my dear sir,
yours truly,
“JAMES D. FORBES.”
In consequence of this, Clerk Maxwell’s first published paper was
communicated to the Royal Society of Edinburgh on April 6th, 1846,
when its author was barely fifteen. Its title is as follows: “On the
Description of Oval Curves and those having a Plurality of Foci. By Mr.
Clerk Maxwell, Junior. With Remarks by Professor Forbes. Communicated
by Professor Forbes.”
The notice in his father’s diary runs: “M. 6 [Ap., 1846.] Royal Society
with Jas. Professor Forbes gave acct. of James’s Ovals. Met with very
great attention and approbation generally.”
This was the beginning of the lifelong friendship between Maxwell and
Forbes.
The curves investigated by Maxwell have the property that the sum found
by adding to the distance of any point on the curve from one focus a
constant multiple of the distance of the same point from a second focus
is always constant.
The curves are of great importance in the theory of light, for if this
constant factor expresses the refractive index of any medium, then
light diverging from one focus without the medium and refracted at a
surface bounding the medium, and having the form of one of Maxwell’s
ovals, will be refracted so as to converge to the second focus.
About the same time he was busy with some investigations on the
properties of jelly and gutta-percha, which seem to have been suggested
by Forbes’ “Theory of Glaciers.”
He failed to obtain the Mathematical Medal in 1846--possibly on account
of these researches--but he continued at school till 1847, when he
left, being then first in mathematics and in English, and nearly first
in Latin.
In 1847 he was working at magnetism and the polarisation of light.
Some time in that year he was taken by his uncle, Mr. John Cay, to see
William Nicol, the inventor of the polarising prism, who showed him the
colours exhibited by polarised light after passing through unannealed
glass. On his return, he made a polariscope with a glass reflector.
The framework of the first instrument was of cardboard, but a superior
article was afterwards constructed of wood. Small lenses mounted on
cardboard were employed when a conical pencil was needed. By means
of this instrument he examined the figures exhibited by pieces of
unannealed glass, which he prepared himself; and, with a camera lucida
and box of colours, he reproduced these figures on paper, taking care
to sketch no outlines, but to shade each coloured band imperceptibly
into the next. Some of these coloured drawings he forwarded to Nicol,
and was more than repaid by the receipt shortly afterwards of a pair of
prisms prepared by Nicol himself. These prisms were always very highly
prized by Maxwell. Once, when at Trinity, the little box containing
them was carried off by his bed-maker during a vacation, and destined
for destruction. The bed-maker died before term commenced, and it
was only by diligent search among her effects that the prisms were
recovered.[9] After this they were more carefully guarded, and they
are now, together with the wooden polariscope, the bits of unannealed
glass, and the water-colour drawings, in one of the showcases at the
Cavendish Laboratory.
About this time, Professor P. G. Tait and he were schoolfellows at the
Academy, acknowledged as the two best mathematicians in the school. It
was thought desirable, says Professor Campbell, that “we should have
lessons in physical science, so one of the classical masters gave them
out of a text-book.... The only thing I distinctly remember about these
hours is that Maxwell and P. G. Tait seemed to know much more about the
subject than our teacher did.”
An interesting account of these days is given by Professor Tait in an
obituary notice on Maxwell printed in the “Proceedings of the Royal
Society of Edinburgh, 1879–80,” from which the following is taken:--
“When I first made Clerk Maxwell’s acquaintance, about
thirty-five years ago, at the Edinburgh Academy, he was a year
before me, being in the fifth class, while I was in the fourth.
“At school he was at first regarded as shy and rather dull.
He made no friendships, and he spent his occasional holidays
in reading old ballads, drawing curious diagrams, and making
rude mechanical models. This absorption in such pursuits,
totally unintelligible to his schoolfellows (who were then
quite innocent of mathematics), of course procured him a not
very complimentary nickname, which I know is still remembered
by many Fellows of this Society. About the middle of his school
career, however, he surprised his companions by suddenly
becoming one of the most brilliant among them, gaining
high, and sometimes the highest, prizes for scholarships,
mathematics, and English verse composition. From this time
forward I became very intimate with him, and we discussed
together, with schoolboy enthusiasm, numerous curious
problems, among which I remember particularly the various plane
sections of a ring or tore, and the form of a cylindrical
mirror which should show one his own image unperverted. I
still possess some of the MSS. we exchanged in 1846 and early
in 1847. Those by Maxwell are on ‘The Conical Pendulum,’
‘Descartes’ Ovals,’ ‘Meloid and Apioid,’ and ‘Trifocal Curves.’
All are drawn up in strict geometrical form and divided into
consecutive propositions. The three latter are connected with
his first published paper, communicated by Forbes to this
society and printed in our ‘Proceedings,’ vol. ii., under the
title, ‘On the Description of Oval Curves and those having a
Plurality of Foci’ (1846). At the time when these papers were
written he had received no instruction in mathematics beyond a
few books of Euclid and the merest elements of algebra.”
In November, 1847, Clerk Maxwell entered the University of Edinburgh,
learning mathematics from Kelland, natural philosophy from J. D.
Forbes, and logic from Sir W. R. Hamilton. At this time, according to
Professor Campbell[10]--
“he still occasioned some concern to the more conventional
amongst his friends by the originality and simplicity of his
ways. His replies in ordinary conversation were indirect and
enigmatical, often uttered with hesitation and in a monotonous
key. While extremely neat in his person, he had a rooted
objection to the vanities of starch and gloves. He had a pious
horror of destroying anything, even a scrap of writing-paper.
He preferred travelling by the third class in railway journeys,
saying he liked a hard seat. When at table he often seemed
abstracted from what was going on, being absorbed in observing
the effects of refracted light in the finger-glasses, or in
trying some experiment with his eyes--seeing round a corner,
making invisible stereoscopes, and the like. Miss Cay used
to call his attention by crying, ‘Jamsie, you’re in a prop.’
He never tasted wine; and he spoke to gentle and simple in
exactly the same tone. On the other hand, his teachers--Forbes
above all--had formed the highest opinion of his intellectual
originality and force; and a few experienced observers, in
watching his devotion to his father, began to have some inkling
of his heroic singleness of heart. To his college companions,
whom he could now select at will, his quaint humour was an
endless delight. His chief associates, after I went to the
University of Glasgow, were my brother, Robert Campbell (still
at the Academy), P. G. Tait, and Allan Stewart. Tait went
to Peterhouse, Cambridge, in 1848, after one session of the
University of Edinburgh; Stewart to the same college in 1849;
Maxwell did not go up until 1850.”
During this period he wrote two important papers. The one, on “Rolling
Curves,” was read to the Royal Society of Edinburgh by Professor
Kelland--(“it was not thought proper for a boy in a round jacket to
mount the rostrum”)--in February, 1849; the other, on “The Equilibrium
of Elastic Solids,” appeared in the spring of 1850.
The vacations were spent at Glenlair, and we learn from letters to
Professor Campbell and others how the time was passed.
“On Saturday,” he writes[11]--April 26th, 1848, just after his
arrival home--“the natural philosophers ran up Arthur’s Seat with the
barometer. The Professor set it down at the top.... He did not set it
straight, and made the hill grow fifty feet; but we got it down again.”
In a letter of July in the same year he describes his laboratory:--
“I have regularly set up shop now above the wash-house at the
gate, in a garret. I have an old door set on two barrels, and
two chairs, of which one is safe, and a skylight above which
will slide up and down.
“On the door (or table) there is a lot of bowls, jugs, plates,
jam pigs, etc., containing water, salt, soda, sulphuric acid,
blue vitriol, plumbago ore; also broken glass, iron, and copper
wire, copper and zinc plate, bees’ wax, sealing wax, clay,
rosin, charcoal, a lens, a Smee’s galvanic apparatus, and a
countless variety of little beetles, spiders, and wood lice,
which fall into the different liquids and poison themselves. I
intend to get up some more galvanism in jam pigs; but I must
first copper the interiors of the pigs, so I am experimenting
on the best methods of electrotyping. So I am making copper
seals with the device of a beetle. First, I thought a beetle
was a good conductor, so I embedded one in wax (not at all
cruel, because I slew him in boiling water, in which he never
kicked), leaving his back out; but he would not do. Then I took
a cast of him in sealing wax, and pressed wax into the hollow,
and blackleaded it with a brush; but neither would that do. So
at last I took my fingers and rubbed it, which I find the best
way to use the blacklead. Then it coppered famously. I melt out
the wax with the lens, that being the cleanest way of getting a
strong heat, so I do most things with it that need heat. To-day
I astonished the natives as follows. I took a crystal of blue
vitriol and put the lens to it, and so drove off the water,
leaving a white powder. Then I did the same to some washing
soda, and mixed the two white powders together, and made a
small native spit on them, which turned them green by a mutual
exchange, thus:--1. Sulphate of copper and carbonate of soda.
2. Sulphate of soda and carbonate of copper (blue or green).”
Of his reading he says:--“I am reading Herodotus’ ‘Euterpe,’ having
taken the turn--that is to say that sometimes I can do props., read
Diff. and Int. Calc., Poisson, Hamilton’s dissertation, etc.”
In September he was busy with polarised light. “We were at Castle
Douglas yesterday, and got crystals of saltpetre, which I have been
cutting up into plates to-day in hopes to see rings.”
In July, 1849, he writes[12]:--
“I have set up the machine for showing the rings in crystals,
which I planned during your visit last year. It answers very
well. I also made some experiments on compressed jellies in
illustration of my props. on that subject. The principal one
was this:--The jelly is poured while hot into the annular space
contained between a paper cylinder and a cork; then, when cold,
the cork is twisted round and the jelly exposed to polarised
light, when a transverse cross, X, not +, appears, with rings
as the inverse square of the radius, all which is fully
verified. Hip! etc. _Q.E.D._”
And again on March 22nd, 1850:--
“At Practical Mechanics I have been turning Devils of sorts.
For private studies I have been reading Young’s ‘Lectures,’
Willis’s ‘Principles of Mechanism,’ Moseley’s ‘Engineering
and Mechanics,’ Dixon on ‘Heat,’ and Moigno’s ‘Répertoire
d’Optique.’ This last is a very complete analysis of all that
has been done in the optical way from Fresnel to the end of
1849, and there is another volume a-coming which will complete
the work. There is in it, besides common optics, all about the
other things which accompany light, as heat, chemical action,
photographic rays, action on vegetables, etc.
“My notions are rather few, as I do not _entertain_ them just
now. I have a notion for the torsion of wires and rods, not
to be made till the vacation; of experiments on the action of
compression on glass, jelly, etc., numerically done up; of
papers for the Physico-Mathematical Society (which is to revive
in earnest next session!); on the relations of optical and
mechanical constants, their desirableness, etc.; and suspension
bridges, and catenaries, and elastic curves. Alex. Campbell,
Agnew, and I are appointed to read up the subject of periodical
shooting stars, and to prepare a list of the phenomena to be
observed on the 9th August and 13th November. The society’s
barometer is to be taken up Arthur’s Seat at the end of the
session, when Forbes goes up, and All students are invited to
attend, so that the existence of the society may be recognised.”
It was at last settled that he was to go up to Cambridge. Tait had been
at Peterhouse for two years, while Allan Stewart had joined him there
in 1849, and after much discussion it was arranged that Maxwell should
enter at the same college.
Of this period of his life Tait writes as follows:--
“The winter of 1847 found us together in the classes of Forbes
and Kelland, where he highly distinguished himself. With the
former he was a particular favourite, being admitted to the
free use of the class apparatus for original experiments. He
lingered here behind most of his former associates, having
spent three years at the University of Edinburgh, working
(without any assistance or supervision) with physical and
chemical apparatus, and devouring all sorts of scientific
works in the library. During this period he wrote two valuable
papers, which are published in our ‘Transactions,’ on ‘The
Theory of Rolling Curves’ and on ‘The Equilibrium of Elastic
Solids.’ Thus he brought to Cambridge, in the autumn of 1850, a
mass of knowledge which was really immense for so young a man,
but in a state of disorder appalling to his methodical private
tutor. Though that tutor was William Hopkins, the pupil to a
great extent took his own way, and it may safely be said that
no high wrangler of recent years ever entered the Senate House
more imperfectly trained to produce ‘paying’ work than did
Clerk Maxwell. But by sheer strength of intellect, though with
the very minimum of knowledge how to use it to advantage under
the conditions of the examination, he obtained the position
of Second Wrangler, and was bracketed equal with the Senior
Wrangler in the higher ordeal of the Smith’s Prizes. His name
appears in the Cambridge ‘Calendar’ as Maxwell of Trinity,
but he was originally entered at Peterhouse, and kept his
first term there, in that small but most ancient foundation
which has of late furnished Scotland with the majority of the
professors of mathematics and natural philosophy in her four
universities.”
While W. D. Niven, in his preface to Maxwell’s collected works (p.
xii.), says:--
“It may readily be supposed that his preparatory training for
the Cambridge course was far removed from the ordinary type.
There had indeed for some time been practically no restraint
upon his plan of study, and his mind had been allowed to follow
its natural bent towards science, though not to an extent
so absorbing as to withdraw him from other pursuits. Though
he was not a sportsman--indeed, sport so-called was always
repugnant to him--he was yet exceedingly fond of a country
life. He was a good horseman and a good swimmer. Whence,
however, he derived his chief enjoyment may be gathered from
the account which Mr. Campbell gives of the zest with which he
quoted on one occasion the lines of Burns which describe the
poet finding inspiration while wandering along the banks of a
stream in the free indulgence of his fancies. Maxwell was not
only a lover of poetry, but himself a poet, as the fine pieces
gathered together by Mr. Campbell abundantly testify. He saw,
however, that his true calling was science, and never regarded
these poetical efforts as other than mere pastime. Devotion
to science, already stimulated by successful endeavour;
a tendency to ponder over philosophical problems; and an
attachment to English literature, particularly to English
poetry--these tastes, implanted in a mind of singular strength
and purity, may be said to have been the endowments with which
young Maxwell began his Cambridge career. Besides this, his
scientific reading, as we may gather from his papers to the
Royal Society of Edinburgh referred to above, was already
extensive and varied. He brought with him, says Professor Tait,
a mass of knowledge which was really immense for so young a
man, but in a state of disorder appalling to his methodical
private tutor.”