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LIFE OF JAMES CLERK MAXWELL

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THE LIFE

OF

JAMES CLERK MAXWELL

WITH A SELECTION FROM HIS CORRESPONDENCE AND OCCASIONAL WRITINGS

AND

A SKETCH OF HIS CONTRIBUTIONS TO SCIENCE

BY

LEWIS CAMPBELL, M.A., LL.D.

PROFESSOR OF GREEK IN THE UNIVERSITY OF ST. ANDREWS

WILLIAM GARNETT, M.A.

LATE FELLOW OF ST. JOHN'S COLLEGE, CAMBRIDGE PROFESSOR OF NATURAL PHILOSOPHY IN UNIVERSITY COLLEGE, NOTTINGHAM

WITH THREE STEEL PORTRAITS, COLOURED PLATES, ETC

iLontion K^

MACMILLAN AND CO.

1882

QC

And SO thou vjast made perfect ! Not a friend Might step between thee and the sore distress Which thoic with strong and j^atient godliness

Enduredst uncomi^laining to the end.

Heroic saint ! Bright sufferer ! Thou dost lend To science a new glory. Midst the press Of boasters, all thy meek -eyed fame confess,

And ivorldlings thine unworldliness commend..

Shine on, pure spirit ! Though we see thee not, Even in, thy passage thou hast purged away

The fogs of earth-born doubt and sense-bound, tJwught From hearts that followed thine all-piercing ray.

And while thou soarest far from humoM view,

Even thy faint image shall our strength renew.

PREFACE.

In a work which has more than one author, it is right to distinguish as far as possible what has been con- tributed by each.

The first part of this book, then, has been mainly composed by the present writer (who has acted as editor), and the second by Mr. Garnett ; but it is due to Mr. Grarnett to add that, while he had the chief share of the labour of collecting materials for the whole biography, and the entire burden of the account here given of Maxwell's contributions to science, the substance of Chapters XI. XII. XIII. is also largely drawn from information obtained through him. The matter of whole pages remains almost in his very words, although for the sake of uniformity and simplicity the first person has still been used in speaking of my own reminiscences.

The narrative of Maxwell's early life has been facilitated (1) by a diary kept by Maxwell's father from 1841 to 1847, and often referred to in these pages as " the Diary ;" (2) by two albums containing a series of water-colour drawings by Maxwell's first cousin, Mrs. Hugh Blackburn {nee Isabella Wedder- burn), the value of which may be inferred from the

Vlll PREFACE.

outlined reproductions of a few of them prepared by Mrs. Blackburn herself as illustrations for this book. They are literally hits out of the past, each contain- ing an exact representation, by a most accurate observer and clever draughtswoman, of some incident which had just happened when the sketch was made. The figures, even as outlined, bring back the persons with singular vividness to the memory of those who knew them.

For these and many other advantages the thanks of the authors are due to Maxwell's relatives, but above all to his widow, not only for the free access she has given them to various documents, such as those mentioned above, but for the generous confid- ence she has reposed in them throughout, and for many important suggestions made by her during the j)rogress of the w^ork.

Their thanks are also due in an especial manner to Professor G. G. Stokes of Cambridge for his kind- ness in reading most of Part II. in MS., and for many valuable suggestions both with regard to the subject matter and the mode of treating it, which were re- ceived from him ; and to Professor P. Gr. Tait of the University of Edinburgh for his zealous and able assistance in many ways.

The book owes much, of course, to those w^ho entrusted the letters here published to the authors' care. Their names are duly mentioned in the course of the work. Our task has also been lightened by the help of those friends whose contributions are inserted with their names. In describine: the life of

PREFACE. IX

one who was so many-sided, it is no small advantage to be thus enabled to register the impression which he made on different men. Even should this occasion slight repetitions and discrepancies, the reader may thus form a fuller and, on the whole, a truer image than could be conveyed by a single narrator. Atten- tion is here particularly directed to the statements in Chapter XIII. by Dr. Paget, the Kev. Dr. Guillemard (of Little St. Mary's, Cambridge), and Professor Hort. As a general rule, no attempt has been made to weave the correspondence into the narrative. The facts relating to each period have been grouped to- gether, and the letters have been appended to these in chronological order.

^ A word should be said respecting Part III. What- ever may be the judgment of critics as to the literary merits of Maxwell's occasional writings in verse, there can be no doubt of their value for the purpose of the present work. Like everything which he did, they are characteristic of him, and some of them have a curious biographical interest. Maxwell was singu- larly reserved in common life, but would sometimes in solitude express his deepest feelings in a copy of verses which he would afterwards silently communi- cate to a friend. Again, he shrank from controversy. But his active mind was constantly playing on con- temporary fallacies, or what appeared so to him, and his turn for parody and burlesque enabled him to give humorous expression to his criticism of mistaken methods. Of the later pieces here reproduced, several appeared in Nature with the signature -^ (which

X PKEFACE.

happens to be the analytical equivalent of the therm o- dynamical formula JCM) ; and one (the " Notes on the President's Address ") was published in Black- looocVs Magazine for December 1874. The greater number are now printed for the first time.

The juvenile verses and translations have been included for the same reason which has led to the prominence given to the early life in Part I. If we are right in our estimate of Maxwell, it must be inter- esting to watch the unfolding of such a mind and character from the first, and this not only for the psychological student, but for all those who share Wordsworth's fondness for "days" that are "linked each to each with natural piety."

While the last sheets were being revised for the press the sad news arrived that Maxwell's first cousin, Mr. Colin Mackenzie, had died on board the Bosnia, on his way home from America. There was no one whose kind encouragement had more stimulated the preparation of this volume, or whose pleasure in it would have been a more welcome reward. But he, too, is gone before his time, and this book will be sent into the world with fewer good wishes. He deserves to be remembered with afiection wherever the name of James Clerk Maxwell is honoured or beloved.

LEWIS CAMPBELL.

August 1882.

CONTENTS.

PAET I.— BIOGEAPHICAL OUTLINE. CHAPTEK I.

PAGE

Birth and Parentage ..... 1

Note. Tlie Clerks of Penicuik and Maxwells of Middlebie 1 6

CHAPTEK 11.

Glenlair— Childhood 1831-1841 .• . .24

CHAPTEE III.

Boyhood 1841-1844 . . . . .45

CHAPTEE lY.

Adolescence 1844-1847 . . . . .66

Note. Oval and Meloid . . . .91

CHAPTEE V.

Opening Manhood 1847-1850 . . .105

CHAPTEE VI.

Undergraduate Life at Cambridge 1850-1854 . 146

XU CONTENTS.

CHAPTEE VII.

PAGE

Bachelor-Scholar and Fellow of Trinity 1854-1856 . 197

CHAPTEE VIII.

Essays at Cambridge 1853-1856 .... 223

CHAPTEE IX.

Death of his Father Professorship at Aberdeen

1856-1857 ...... 247

CHAPTEE X.

Aberdeen Marriage 1857-1860 . . . 274

CHAPTEE XL

King's College, London Glenlair 1860-1870 . . 314

CHAPTEE XIL

Cambridge 1871-1879 ..... 348

. CHAPTEE XIIL

Illness and Death 1879 . . . . . 406

CHAPTEE XIV.

Last Essays at Cambridge . . . . .434

CONTENTS. Xlll

PART IL— CONTRIBUTIONS TO SCIENCE.

PAGE

1. Experiments on Colour Vision, and other Contribu-

tions TO Optics . . . . .465

2. Investigations respecting Elastic Solids . . 491

3. Pure Geometry . . . . .496

4. Mechanics . . . . . .498

5. Saturn's Rings ..... . 501

6. Faraday's Lines op Force, and Maxwell's Theory of

THE Electromagnetic Field, including the Electromagnetic Theory of Light, and other Investigations in Electricity . . .513

7. Molecular Physics . . •. ' . . 559

PART III.— POEMS.

1. Juvenile Verses and Translations . . .577

2. Occasional Pieces . . . . .593

3. Serio-Comic Verse .... 609

INDEX . . . . . . .653

LIST OF ILLUSTEATIONS.

STEEL PLATES.

JAMES CLERK MAXWELL. Engraved by Stodart, after a

Photograph by Fergus of Greenock . . Frontispiece.

John Clerk Maxwell, ^t. 66. Engraved by Stodart,

after Sir John Watson Gordon, R. A. . To face page 1 1

Mrs. Clerk Maxwell and "Boy." Engraved by Stodart,

after William Dyce, R.A. . . To face page 29

LITHOGRAPHS. Facsimile Letter . . . . To face page 58

The Vampyre, Compylt into Meeter, by Jas. Clerk

Maxwell .... To face page 70

COLOURED PLATES. Diagram showing the Relations of Light To face page 473

Diagram illustrating the Chromatic Relations of

Coloured Papers . . . To face page 4:1 4:

XVI LIST OF ILLUSTRATIONS.

Chromatic Effects op a Pentagon of Unannealed Glass

IN Polarised Light . . . To face page AS)!

ISOCHROMATIC LiNES IN A TRIANGLE OF UnANNEALED

Glass ..... To face page 4S7

Diagram showing the Colours exhibited by a Plate of

Gelatine when exposed to a Torsional Shear To face page 491

PART L

CHAPTEE I.

INTKODUCTORY BIRTH AND PARENTAGE.

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.

But there was more in James Clerk Maxwell than is implied in any praise that can be awarded to the discoverer, or in the honour justly due to the educa- tional reformer, much, indeed, which his friends feel they can but partly estimate, and still less adequately describe.

We have, notwithstanding, undertaken this im- perfect Memoir of him, in which the purpose of this First Part will be to trace the growth from childhood to maturity, and to record the untimely death, of a man of profound original genius, who was also one of the best men who have lived, and, to those who knew him, one of the most delightful and interesting of human beings.

If I can bring before the reader s mind, even in shadowy outline, the wise and gentle but curiously

2 JAMES CLERK MAXWELL. [CHAP. I.

blended influences which, formed the cradle of his young imagination, the channels through which ideas reached him from the past, the objects which most challenged his observation and provoked his inven- tion, his first acquaintance with what permanently- interested him in contemporary speculation and discovery, and the chief moments of his own in- tellectual progress in earlier years, such record should have a right to live. And it may be that a congenial spirit here and there may look with me into the depths of this unique personality, and feel the value of the impulses, often seem- ingly wayward, and strange even to himself, with which the young eagle " imped his wings " for flight, or taught his eyes to bear the unclouded light. And many to whom modern Science is a sealed book may find an interest in observing the combination of extraordinary gifts with a no less remarkable simpli- city and strength of character.

James Clerk Maxwell was born at No. 14 India Street, Edinburgh, on the 13th of June 1831. His parents were John Clerk Maxwell, one of the Clerks of Penicuik, in Midlothian, and Frances, daughter of K. H. Cay, Esq. of N. Charlton, Northumberland. Excepting a daughter, Elizabeth, who had died in infancy, James was their only child.

Edinburgh was at this time the natural meeting- place for the best spirits of the North. How much of intellect and individuality, of genuine though often eccentric worth, of high thinking and plain living, then forgathered in Auld Keekie, and found ample

CHAP. I.] BIRTH AND PARENTAGE. 3

scope and leisure there, is known to the lovers of Sir W. Scott and to the readers of Lord Cockburn both prominent figures in the Edinburgh of 1824-1831.

And the agora of " Modern Athens " was the Parliament House. There the heir-presumptive could while away his time of waiting for " dead men's shoon"; there the laird's brother might qualify for some berth hereafter to be provided for him ; and the son of those whose ancestral estates had been impaired by rashness or misfortune, and who had perchance sought the asylum of the Abbey, might hope through honourable industry to restore the fallen house, or even to win new lustre for an ancient name.

When John Clerk Maxwell, after leaving the University, first sought those purlieus of the law, he was already a laird, although a younger brother. For he had inherited the estate of Middlebie, which, by the conditions of the entail under which it had descended from the Maxwells,^ could not be held to- gether with Penicuik, and was therefore necessarily relinquished by Sir George Clerk in favour of his brother John. This arrangement had been completed when the two brothers were boys together at the High School, and were living in George Square with their mother and their sister Isabella. Their father, James Clerk,^ who died before his elder brother. Sir John, was a naval captain in the H.E.I.C.S., but retired

1 See below, pp. 16-23. 2 He is said to have played well on the bagpipes, and a set of pipes was until recently preserved at Glenlair, of which the following siDgular

4 JAMES CLERK MAXWELL. [CHAP. I.

early, and married Miss Janet Irving, who thus be- came the mother of Sir George Clerk and of John Clerk Maxwell. When Sir George had come of age, and taken up his abode at Penicuik, John Clerk Max- well continued living with his mother, Mrs. Clerk, in Edinburgh. About 1820, in order to be near Isabella, Mrs. Wedderburn, they ''flitted" to a house in the New Town, No. 14 India Street, which was built by special contract for them. Mrs. Clerk died there in the spring of 1824.

The old estate of Middlebie had been considerably reduced, and there was nothing in what remained of it to tempt its possessor, while a single man, to leave Edinburgh, or to break off from his profession at the Bar. There was not even a dwelling-house for the laird. Mr. Clerk Maxwell therefore lived in Edin- burgh until the age of thirty- six, pacing the floor of the Parliament House, doing such moderate business as fell in his way, and dabbling between -whiles in scientific experiment. In vacation time he made various excursions in the Highlands of Scotland and in the north of England, and kept a minute record of his observations.

But when, after his mother's death, he had married a lady of tastes congenial to his own and of a sanguine active temperament, his strong natural bent towards a country life became irresistible. The pair soon con- story was told : Captain James Clerk was wrecked in the Hooghly and swam ashore, using the bag of his pipes for a float ; and when he gained the shore he " played an unco' fit," whereby he not only cheered the survivors, but frightened the tigers away.

CHAP. I.]

BIRTH AND PARENTAGE.

ceived a wish to reside upon their estate, and began to form plans for doing so ; and they may be said to have lived thenceforth as if it and they were made for one another. They set themselves resolutely to the work of making that inheritance of stony and mossy ground to become one of the habitable places of the earth. John Clerk Maxwell had hitherto

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appeared somewhat indolent ; and there was a good deal of inertia in his composition. But the latent forces of his character were now to be developed.

He was one of a race ^ in whom strong individuality had occasionally verged on eccentricity. For two centuries the Clerks had been associated with all that was most distinguished in the Northern kingdom, from Drummond of Hawthornden to Sir Walter Scott. Each generation had been remarkable for the talents and accomplishments of some of its members ; and it was natural that a family with such ante-

* The note appended to this chapter contains a sketch of the family history of the Clerks and Maxwells, which those who believe in heredity, as Maxwell did, will do well to read.

6 JAMES CLERK MAXWELL. [CHAP. I.

cedents should have acquired something of clannish - ness. But any narrowing effect of such a tendency was counteracted by a strong intellectual curiosity, which kept them en rapport with the world, w^hile they remained independent of the world. And as each scion of the stock entered into new relations, the keen mutual interest, instead of merely narrow- ing, became an element of width. I speak now of the generation preceding our own. No house was ever more affluent in that Coterie-Sprache, for which the Scottish dialect of that day afforded such full materials. It would be pleasant, if possible, to recall that humorous gentle speech, as it rolled the cherished vocables like a sweet morsel on the tongue, or minced them with a lip from which nothing could seem coarse or broad, caressing them as some Lady Bountiful may caress a peasant's child, or as it coined sesquipedalia verba, which passed current through the stamp of kindred fancy. This quaint freemasonry was un- consciously a token not only of family community, but also of that feudal fellowship with dependents which was still possible, and which made the language and the manners of the most refined to be often racy of the soil. But Time will not stand still, and neither the delicate "couthy" tones, nor that which they signified, can be fully realised to-day. But we can still in part appreciate the playful irony which prompted these humorous vagaries of old leisure, wherein true feeling found a modest veil, and a naive philosophy lightened many troubles of life by making light of them.

CHAP. I.] BIRTH AND PARENTAGE. 7

Mr. John Clerk Maxwell's own idiosyncrasy, as has been said, was well suited for a country life. But to give a true idea of him it is necessary to be more precise. His main characteristic, beyond a warm, affectionate heart, the soundest of sound sense, and absolute sincerity, was a persistent practical interest in all useful processes} When spending his holidays at Penicuik as a boy from the Edinburgh High School (as well as long afterwards), he took delight in watching the machinery of Mr. Cowan's paper-mill, then recently established in that neighbourhood. And Mr. K. D. Cay remembers him, when still a young man living in India Street with his mother (about 1821-24), to have been engaged, together with John Cay, who was after-

^ He never lost an opportunity of inspecting manufactures, or of visiting great buildings, ecclesiastical or otherwise, and he impressed the same habit upon his son. The " works " they " viewed " together were simply innumerable, but it will be sufficient to cite one crowning instance. When James Clerk Maxwell was in the midst of his last year's preparation for the Cambridge Tripos, he proposed to spend the few days of Easter vacation which the pressure of his work allowed to him, in a visit to a friend at Birmingham. His father had seen Bir- mingham in his youth, and gave him the following instructions, which were mostly carried out : " View, if you can, armourers, gunmaking and gunproving swordmaking and proving Papier-mdcMe and japanning silver-plating by cementation and rolling ditto, electro- type— Elkington's works Brazier's works, by founding and by strik- ing out in dies turning spinning teapot bodies in white metal, etc. making buttons of sorts, steel pens, needles, pins, and any sorts of small articles which are curiously done by subdivision of labour and by ingenious tools glass of sorts is among the works of the place, and all kinds of foundry works engine-making tools and instruments optical and [philosophical], both coarse and fine. If you have had enough of the town lots of Birmingham, you could vary the recreation by viewing Kenilworth, Warwick, Leamington, Stratford-on- Avon, or such like." James began with the glassworks.

8 JAMES CLERK MAXWELL. [CHAP. I.

wards his brother-in-law, in a series^of attempts to make a bellows that should have a continuous even blast. We can readily imagine, therefore, how closely he must have followed every step in the gradual application of steam to industry, and the various mechanical improvements which took place in his youth and early manhood.^

His practical thoroughness was combined with a striking absence of conventionality and contempt for ornament. In matters however seemingly trivial nothing that had to be done was trivial to him he considered not what was usual, but what was best for his purpose. In the humorous language which he loved to use, he declared in favour of doing things with judiciosity. One who knew him well describes him as always balancing one thing with another exercis- ing his reason about every matter, great or small. He was fond of remarking, for example, on the folly of coachmen in urging a horse to speed as soon as they saw the top of a hill, when, by waiting half a minute until the summit was really attained, they might save the animal. " A sad waste of work," he would say. Long before the days of " anatomical " bootmaking, he insisted on having ample room for his feet. His square-toed shoes were made by a country shoemaker under his direction on a last of his own and out of a piece of leather chosen by himself. This

1 In 1831 he contributed to the Edinburgh Medical and Philo- sophical Journal (vol. x.) a paper entitled, " Outlines of a Plan for comhinjLiig Machinery with the Manual Printing Press." His acme of festivity was to go with his friend John Cay (the " partner in his revels "), to a meeting of the Edinburgh Royal Society.

CHAP. I.] BIRTH AND PARENTAGE. 9

is only one example of the manner in which he did everything. It was thought out from the beginning to the end, and so contrived as to be most economical and serviceable in the long run. In his Diary (1841) we find him cutting out his own and his son's shirts, while planning the outbuildings which still exist at Glenlair. And he not only planned these, but made the working plans for the masons (1842) with his own hand.^ This habitual careful adaptation of means to ends was the characteristic which (together with profound simplicity) he most obviously trans- mitted to his son. Its effect, heightened by perfect science, is still apparent in the construction and arrangement of the Cavendish Laboratory at Cam- bridge.

While thus unostentatious and plain in all his ways, he was essentially liberal and generous. No one could look in his broad face beaming with kindli- ness and believe otherwise. But his benevolence was best known nearest home. And in caring for others, as in providing for his own house, his actions were ruled, not by impulse, but persistent thoughtfulness. By his ever-wakeful consideration, he breathed an atmosphere of warm comfort and quiet contentment on all (including the dumb animals) within his sphere. Whoever had any claim upon his afiectionate heart, whether as an old dependant, or as a relation or

^ The following entry from the Diary (1842) will be appreciated by those who are interested in the country life of a past generation : " Wrote to Nanny about check of the yarn of the dead Hogs, to make trowser stuff or a plaid."

10 JAMES CLERK MAXWELL. [CHAP. L

friend, miglit command from him any amount of patient thought, and of pains given without stint and without complaint. His ''judiciosity'' was used as freely for them as for himself.^ And where need was he could be an efifectual peacemaker.

He was assiduous also in county business (road meetings, prison boards, and the like), and in his own quiet way took his share in political movements, on the Conservative side.

There was a deep unobtrusive tenderness in him, which in later years gave a touching, almost femi- nine, grace to his ample countenance, and his portly, even somewhat unwieldy, frame. ^ He was a keen sportsman (unlike his son in this), and an excellent shot; but it was observed that he was above all careful never to run the risk of wounding without killing his game.

His temper was all but perfect ; yet, as " the best laid schemes o' mice and men gang aft agley," the minute care with which he formed his plans some- times exposed him to occasions which showed that his usual calm self-possession was not invulnerable. At such times he would appear not angry, only some- what discomposed or " vexed," and, after donning his considering-cap for a little while, would soon resume his benign equanimity.

^ Mr. Colin Mackenzie says : " He was the confidential friend of his widowed sister Mrs. Wedderburn's children, who were in the habit of referring to him in all their difficulties in perfect confidence that he would help them, and regarded him more as an elder brother than anything else." This is abundantly confirmed by various entries in the Diary.

2 Entry in Diary, Nov. 9, 1844. Weighed 15 st. 7 lbs.

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CHAP. I.] BIRTH AND PARENTAGE. 11

An interesting trait is revealed to us by the Diary. Minute as the entries are for day after day, things which, if mentioned, might reflect unfavourably upon others, are invariably omitted. They have come down through other channels, but in this scrupulous record they have left no trace.

His otherwise happy life was crossed with one deep, silent sorrow, but was crowned with one long comfort in the life of his son. They were bound to- gether by no ordinary ties, and were extremely like in disposition, in simplicity, unworldliness, benevo- lence, and kindness to every living thing. Those who knew Maxwell best will be least apt to think irrelevant this somewhat lengthy description of his father.

The portrait of Mr. John Clerk Maxwell by Watson Gordon is a faithful representation of a face which returns more vividly than most others to the eye of memory, but no portrait can restore " the busy wrinkles round his eyes," or give back to them their mild radiance

" Gray eyes lit up With summer Hghtnings of a soul

So full of summer warmth, so glad, So healthy, sound and clear and whole,

His memory scarce can make me sad."

He lived amidst solid realities, but his vision was neither shallow nor contracted. And his sense of things beyond, if inarticulate, was, in later life at least, not the less serious and profound. Yet those who shall compare this likeness with the study of James Clerk Maxwell's head by Mrs. Blackburn, may at

12 JAMES CLERK MAXWELL. [CHAP. I.

once detect something of the difference between the father and the son. In the one there is a grave and placid acquiescence in the nearer environment, the very opposite of enthusiasm or mysticism; in the other, the artist has succeeded in catching the un- earthly look which often returned to the deep -set eyes under the vaulted brow, when they had just before been sparkling with fun, the look as of one who has heard the concert of the morning stars and the shouting of the Sons of God.

James himself has said to me that to have had a wise and good parent is a great stay in life, and that no man knows how much in him is due to his pro- genitors. And yet the speculative ideal element which was so strong in him the struggle towards the infinite through the finite was not prominent in either of his parents. Mrs. Clerk Maxwell was, no doubt, a good and pious (not bigoted) Episcopalian ; but, from all that appears, her chief bent, like that of her husband, must have been practical and matter-of- fact. Her practicality, however, was different from his. She was of a strong and resolute nature, as prompt as he was cautious and considerate, more peremptory, but less easily perturbed. Of gentle birth and breed- ing, she had no fine-ladyisms, but with blunt deter- mination entered heart and soul into that rustic life. It is told of her that when some men had been badly hurt in blasting at a quarry on the estate, she person- ally attended to their wounds before a surgeon could be brought, and generally that wherever help was needed she was full of courage and resource. She

CHAP. I.] BIRTH AND PARENTAGE. 13

was very intelligent and ingenious, played well on the organ, and composed some music, but in other respects was less "accomplished" than most of her family, except in domestic works, and above all in knitting, which in those days was an elegant and most elabo- rate pursuit.

Her father, E. Hodshon Cay, Esq., of N. Charlton, is thus spoken of in Lockhart's Life of Scott (p. 86 of the abridged edition, 1871) :—" I find him " (Scott) " further nominated in March 1796, together with Mr. Robert Cay, an accomplished gentleman, afterwards Judge of the Admiralty Court in Scotland, to put the Faculty's cabinet of medals in proper arrangement." Mr. Cay at one time held the post of Judge-Admiral and Commissary-General, and while thus dignified in his profession used to reside for part of the year on his hereditary estate of Charlton, which had been freed from certain burdens ^ upon his coming of age.

He married Elizabeth Liddell, daughter of John Liddell, Esq., of Tynemouth, about the year 1789. The eldest son, John, has been already mentioned as an early companion of John Clerk Maxwell's, and both his name and those of Jane and E. D. Cay will reappear in the sequel. Between Frances (Mrs. Clerk Maxwell) and her sister Jane, who was never married, there existed a very close afiection. There is a picture of them both as young girls (a three-quarter length in water-colours) done by their mother, who was an accomplished artist. Her gift in

^ Incurred by his father in successfully resisting some manorial claims. These debts had brought the family to Edinburgh.

14 JAMES CLERK MAXWELL. [CHAP. I.

this way, which was very remarkable, and highly cultivated for an amateur, was continued in Jane and Eobert, and has been transmitted to the succeeding generation. Miss Jane Cay was one of the warmest hearted creatures in the world ; somewhat wayward in her likes and dislikes, perhaps somewhat warm- tempered also, but boundless in affectionate kindness to those whom she loved. Mr. K. D. Cay, W.8., married a sister of Dyce the artist, and, after acting for some time as one of the Judges' clerks, proceeded in 1844 to Hong-Kong, where he had an appointment. His wife joined him there in 1845, and died in 1852. In two of their sons, besides the artistic tastes which they inherited through both parents, there was de- veloped remarkable mathematical ability. It should be also noticed that Mr. John Cay, the Sheriff of Linlithgow, though not specially educated in mathe- matics, was extremely skilful in arithmetic and fond of calculation as a voluntary pursuit. He was a great favourite in society, and full of general information. We have already seen him assisting at experiments which might have led to the invention of " blowing fans," but seem to have produced no such profitable result. And we shall find that his interest in practical Science was continued late in after life.^

In speaking of the Cay family it has been necessary to anticipate a little, in order to advert to some par- ticulars which, although later in time, seemed proper

^ It should be remembered that in tbe early years of tbe century considerable interest in experimental science bad been awakened in Edinburgh through the teaching of Professors Playfair and Hope.

CHAP, l] ' BIRTH AND PARENTAGE. 15

to an introduction. Having departed so far from the order of events, I may before concluding this chapter make explicit mention of the loss which coloured the greater part of James Clerk Maxwell's existence, by leaving him motherless in his ninth year. Mrs. Clerk Maxwell died on the 6th of December 1839. There was extant until after Professor Maxwell's death a memorandum or diary kept at the time by her husband, describing the heroic fortitude which she had shown under the pain of her disease, and of the operation by which they had attempted to save her. Anaesthetics were then unknown. She had nearly completed her forty-eighth year, having been born on the 25th of March 1792, and married at the age of 34 (October 4, 1826). Mr. Maxwell was aged fifty-two at the time of his wife's death. He did not marry again.

We now return from this sad record to the birth of the son and heir, which was the more welcome to the parents after the loss of their first-born child. At this joyful epoch Mr. and Mrs. Clerk Maxwell, though retaining the house in India Street, had been already settled for some years in their new home at Glenlair.

16 JAMES CLERK MAXWELL. [CHAP. I.

NOTE.

THE CLERKS OF PENICUIK AND MAXWELLS OF MIDDLEBIE.

Miss Isabella Cleek, of 3 Hobart Place, London, lias kindly furnished me with the following statement, to which I have added some annotations. These are chiefly derived from a book of autograph letters, which was long kept at Glenlair, and is now in the possession of Mrs. Maxwell.

" The Clerks of Penicuik are descended from John Clerk, of Kilhuntly, in Badenoch, Aberdeenshire, who attached himself to the party of Queen Mary, and had to leave that part of the country in 1568 during the troubles. His son, William Clerk, was a merchant in Montrose ; he lived in the reigns of Mary and James the Sixth, and died in 1620.

" John Clerk, his son, was a man of great ability. He went to Paris in 1634, and having acquired a large fortune there in commerce, returned to Scotland in 1646, and bought the barony of Penicuik, and also the lands of Wright's Houses. He married Mary, daughter of Sir William Gray, of Pittendrum. This lady brought the necklace of Mary Queen of Scots into the family, through her mother, Mary Gillies, to whom it was given by Queen Mary before her execution. He died in 1674. His eldest son John was created a Baronet of Nova Scotia in 1679."

This Sir John Clerk (the first baronet) records a singular affray with sixteen robbers who attacked the house of Penicuik in 1692. He kept them at bay until the neighbouring tenants came to his relief. His pluck, sagacity, presence of mind, good feeling, and piety, are conspicuous in the narrative.

CHAP. I.] CLERKS OF PENICUIK. l7

"He served in the Parliament of Scotland, and ac- quired the lands and barony of Lasswade. He married Elizabeth, daughter of Henry Henderson, Esq., of Elvington, and grand-daughter of Sir William Drummond, of Haw- thornden, the poet. Sir William Drummond had only two daughters, the younger of whom married W. Henderson. Their daughter Elizabeth was wonderfully talented and accomplished, and had a special gift for music. Sir John died in 1722. He was succeeded by his eldest son, Sir John Clerk, a man of great learning, who was appointed in 170 7 one of the Barons of the Exchequer in Scotland, which judicial employment he retained during the remainder of his life. He was also one of the Commissioners of the Union."

The Baron's precepts to his son George when at school in Cumberland are worthy of Polonius. He advises him to be kind to his companions, as he could not tell what they might be able to do for him thereafter, and to be sure to take the opportunity of " learning the English language," in which the Baron himself regrets his own deficiency. " You have nothing else to depend on but your being a scholar and behaving well." He is described in the autumn of his days as " humming along and stuffing his pipe in order to whiff it away for half an hour," while *' my lady is engaged reading over some newspaper. Miss Clerk is labour- ing with great industry at a very pretty open muffler. Mrs. Dean is winding three fine white clews upon a fourth one," etc. " My lady's " letters to her son George dwell much on family matters, and are full of old-fashioned piety.

" He was highly accomplished in music, painting, and languages. At the age of nineteen he went abroad for three years to finish his education. He studied one year under the celebrated Dr. Boerhaave at Leyden, where he was a pupil of William Mieris in drawing. He afterwards went to Florence and Eome, where he had lessons in music from Antonio Corelli, and in painting from Imperiale. He wrote an opera which was performed in Eome. His brother, William Clerk, married Agnes Maxwell, heiress of Middlebie, in Dumfriesshire."

18 JAMES CLERK MAXWELL. [CHAP. L

William also was at Leyden before going into business as a lawyer, and kept a journal of his tour in Holland, which, like other writings of the Clerk family, is furnished with pen and ink sketches of what he saw. His letters are interesting from the combination of earnest, Covenanting piety, with a gay and chivalrous bearing in what was evidently the one serious love- passage of his life. His letters to his wife in the years after their marriage are as full of tenderness as that in which he makes his first proposal is instinct with old-world gallantry.

" They left an only daughter, Dorothea, who married her first cousin, afterwards Sir George Clerk Maxwell."

This George Clerk Maxwell probably sufi'ered a little from the world being made too easy for him in early life. Such a mis- fortune was all but inevitable, and the Baron seems to have done his best to obviate it by good counsel ; but the current of circum- stances was too strong. George was in the habit of preserving letters, and from those received by him before succeeding to Penicuik it is possible to form a tolerably full impression of the man. In some respects he resembled John Clerk Maxwell, but certainly not in the quality of phlegmatic caution. His imagi- nation seems to have been dangerously fired by the " little knowledge " of contemporary science which he may have picked up when at Leyden with his elder brother James (see p. 1 9, 11. 1 8, 25). We find him, while laird of Dumcrieff, near Mofi'at, practically interested in the discovery of a new " Spaw," and humoured in this by his friend Allan Eamsay, the poet : by and by he is deeply engaged in prospecting about the Lead Hills, and receiving humorous letters on the subject from his friend Dr. James Hutton, one of the founders of geological science, and author of the Theory of the Earth} After a while he has commenced active operations, and is found making fresh proposals to the Duke of Queensberry. Then to the mines there is added some talk of

^ See " Biographical Account of the late Dr. James Hutton, F.E.S., Edinburgh," read by Mr. Playfair, in Transactions of the Royal Society of Edinburgh^ vol. v. He made a tour in the north of Scotland in 1764, "in company with Commissioner, afterwards Sir George, Clerk, in which Dr. Hutton's chief object was mineralogy, or rather geology, which he was now studying with close attention."

CHAP. I.] CLERKS OF PENICUIK. 19

a paper manufactory, and the Duchess playfully " congratulates "" his " good self on every new sprouting up manufacture by means of so good a planter and planner." But by this time it has been found advisable to add to his studies some more certain source of income, and he applies for the Postmastership, and (through the Duke of Q.) obtains an office in the Customs. In this, as in all relations of life, he seems to have won golden opinions. And ere he succeeded to Penicuik, the loss of Middlebie proper and Dumcrieff had doubtless taught the lesson of prudence which hi& father the Baron had vainly tried to impress upon his youth. The friendship of Allan Ramsay and the affectionate confidence of the " good Duke and Duchess of Queensberry," sufficiently indicate the charm which there must have been about this man.

" Sir John Clerk (the Baron of Exchequer) married Janet Inglis of Cramond, and was succeeded by his eldest son, Sir James Clerk, in 1755. Sir James died without children in 1782, and was succeeded