MAXWELL, James Clerk (1831-1879), was the last representative of a younger branch of the well-known Scottish family of Clerk of Penicuik. He was educated at the Edinburgh Academy (1840-47) and the university of Edinburgh (1847-50). Entering at Cambridge in 1850, he spent a term or two in Peterhouse, but afterwards migrated to Trinity. He took his degree in 1854 as second wrangler, and was declared equal with the senior wrangler of his year in the higher ordeal of the Smith’s prize examination. He held the chair of natural philosophy in Marischal College, Aberdeen, from 1856 till the fusion of the two colleges there in 1860. For eight years subsequently he held the chair of physics and astronomy in King’s College, London, but resigned in 1868 and retired to his estate of Glenlair in Kirkcudbrightshire. He was summoned from his seclusion in 1871 to become the first holder of the newly-founded professorship of experimental physics in Cambridge; and it was under his direction that the plans of the Cavendish laboratory were prepared. He superintended every step of the progress of the building and of the purchase of the very valuable collection of apparatus with which it was equipped at the expense of its munificent founder the duke of Devonshire (chancellor of the university, and one of its most distinguished alumni). So far for the outline of Maxwell’s career, as regards dates, official work, &c. The rest belongs almost exclusively to mathematical and physical science. For more than half of his brief life he held a prominent position in the very foremost rank of natural philosophers. His contributions.to scientific societies began in his fifteenth year, when Professor J. D. Forbes communicated to the Royal Society of Edinburgh a short paper of his on a mechanical ...method of tracing Cartesian ovals. In his eighteenth year, while still a student in Edinburgh, he contributed two valuable papers to the Transactions of the same society—one of which, “On the Equilibrium of Elastic Solids,” is remarkable, not only on account of its intrinsic power and the youth of its author, but also because in it he laid the foundation of one of the most singular discoveries of his later life, the temporary double refraction produced in viscous liquids by shearing stress. Immediately after taking his degree, he read to the Cambridge Philosophical Society a very novel memoir On the Transformation of Surfaces by Bending. This is one of the few purely mathematical papers he published, and it exhibited at once to experts the full genius of its author. About the same time appeared his elaborate memoir On Faraday’s Lines of Force, in which he gave the first indication of some of those extraordinary electrical investigations which culminated in the greatest work of his life. He obtained in 1859 the Adams prize in Cambridge for a very original and powerful essay On the Stability of Saturn’s Bings. From 1855 to 1872 he published at intervals a series of valuable investigations connected with the Perception of Colour and Colour-Blindness. For the earlier of these he received the Rumford medal in 1860. The instruments which he devised for these investigations were simple and convenient, but could not have been thought of for the purpose except by a man whose knowledge was co-extensive with his ingenuity. One of his greatest investigations bore on the Kinetic Theory of Gases. Originating with D. Bernoulli, this theory’ was advanced by the successive labours of Herapath, Joule, and particularly of Clausius, to such an extent as to put its general accuracy beyond a doubt. But by far the greatest developments it has received are due to Maxwell, part of whose mathematical work has recently been still further extended in some directions by Bolzmann. In this field Maxwell appears as an experimenter (on the laws of gaseous friction) as well as a mathematician. His two latest papers deal with this branch of physics; one is an extension and simplification of some of Bolzmann’s chief results, the other treats of the kinetic theory as applied to the motion of the radiometer. He has written an admirable text-book of the Theory of Heat, which has already (1882) gone through several editions, and a very excellent elementary treatise on Matter and Motion. Even this, like his other and larger works, is full of valuable matter, worthy of the most attentive perusal not of students alone but of the very foremost scientific men.
But the great work of his life was devoted to electricity. He began by reading with the most profound admiration and attention the whole of Faraday’s extraordinary selfrevelations, and proceeded to translate the ideas of that master into the succinct and expressive notation of the mathematicians. A considerable part of this translation was accomplished during his career as an undergraduate in Cambridge. The writer had the opportunity of perusing the MS. on Faraday's Lines of Force, in a form little different from the final one, a year before Maxwell took his degree. His great object, as it was also the great object of Faraday, was to overturn the idea of action at a distance. The splendid researches of Poisson and Gauss had shown how to reduce all the phenomena of statical electricity to mere attractions and repulsions exerted at a distance by particles of an imponderable on one another. Sir W. Thomson had, in 1846, shown that a totally different assumption, based upon other analogies, led (by its own special mathematical methods) to precisely the same results. He treated the resultant electric force at any point as analogous to the flux of heat from sources distributed in the same manner as the supposed electric particles. This paper of Thomson’s, whose ideas Maxwell afterwards developed in an extraordinary manner, seems to have given the first hint that there are at least two perfectly distinct methods of arriving at the known formulae of statical electricity. The step to magnetic phenomena was comparatively simple; but it was otherwise as regards electromagnetic phenomena, where current electricity is essentially involved. An exceedingly ingenious, but highly artificial, theory had been devised by Weber, which was found capable of explaining all the phenomena investigated by Ampère, as well as the induction currents of Faraday. But this was based upon the assumption of a distance-action between electric particles, whose intensity depended on their relative motion as well as on their position. This was, of course, even more repugnant to Maxwell’s mind than the statical distance-action developed by Poisson. The first paper of Maxwell’s in which an attempt at an admissible physical theory of electromagnetism was made was communicated to the Royal Society in 1867. But the theory, in a fully developed form, first appeared in his great treatise on Electricity and Magnetism (1873). This work, already in a second edition, is one of the most splendid monuments ever raised by the genius of a single individual. Availing himself of the admirable generalized coordinate system of Lagrange, Maxwell has shown how to reduce all electric and magnetic phenomena to stresses and motions of a material medium, and, as one preliminary, but excessively severe, test of the truth of his theory, has shown that (if the electromagnetic medium be that which is required for the explanation of the phenomena of light) the velocity of light in vacuo should be numerically the same as the ratio of the electromagnetic and electrostatic units. We do not as yet certainly know either of these quantities very exactly, but the means of the best determinations of each separately agree with one another more closely than do the various values of either. There seems to be no longer any possibility of doubt that Maxwell has taken the first grand step towards the discovery of the true nature of electrical phenomena. Had he done nothing but this, his fame would have been secured for all time. But, striking as it is, this forms only one small part of the contents of his truly marvellous work.
One of his last great contributions to science was his editing (with copious original notes) the Electrical liesearches of the Hon. Henry Cavendish, which had been altogether unappreciated by the witlings to whom they had previously been confided. It now appears that Cavendish, already famous by many other researches (such as the mean density of the earth, the composition of water, <fcc,), must be looked on as, in his day, a man of Maxwell’s own stamp as a theorist, and an experimenter of the very first rank.
This encyclopaedia has been, in its scientific aspects, greatly indebted to Clerk Maxwell. The articles Atom, Attraction, Capillarity, Diffusion, Ether, &c., were intended as parts merely of one comprehensive system, in which a general résumé of all that is known of the properties of matter should be given in simple yet profound completeness. The reader of these articles cannot but feel how much has been lost when this splendid series cannot be completed by its initiator.
In private life Clerk Maxwell was one of the most lovable of men, a sincere and unostentatious Christian. Though perfectly free from any trace of envy or ill-will, he yet showed on fit occasion his contempt for that pseudo-science which seeks for the applause of the ignorant by professing to reduce the whole system of the universe to a fortuitous sequence of uncaused events.
His collected works will shortly be issued from the Pitt press; and an extended biography, by his former schoolfellow and lifelong friend Professor Campbell, has just been published (1882). (p. g. t.)
MAXWELL, Sir William Stirling-, Bart. (1818— 1878), man of letters, the only son of Mr Archibald Stirling of Keir, Perthshire, and of Elizabeth, second daughter of Sir John Maxwell, seventh baronet of Pollok, Renfrewshire, was born at Kenmure, near Glasgow, in 1818. William Stirling was educated at Trinity College, Cambridge, where he graduated in 1839, and afterwards he spent some years on the Continent chiefly in France and Spain. Having succeeded his father as proprietor of Keir in 1846 (when he was made vice-lieutenant of Perthshire), he in 1852 entered parliament as member for that county; and he was several times re-elected. On the death of his uncle in 1865 he succeeded to the baronetcy and estates of Pollok, in respect of which he assumed the additional name of Maxwell. In the same year he became deputylieutenant of Lanarkshire, and a like office was conferred on him in Renfrewshire in 1870. The services which his talent, energy, and wealth enabled him to render to literature were recognized in a great variety of ways by numerous universities; in 1863 he was chosen lord rector of St Andrews, in 1871 the same honour was conferred by Edinburgh, and in 1875 he became chancellor of Glasgow. In the following year he was created a Knight of the Thistle, being the only commoner of the order. He died at Venice on January 15, 1878.
Sir W. Stirling-Maxwell’s works, which are invariably characterized by thoroughness of workmanship and refinement of literary taste, were in some cases issued for private circulation only, and almost all of them are now exceedingly rare. They include an early volume of verse (Songs of the Holy Land, 1847), and several volumes containing costly reproductions of old engravings, along with valuable explanatory matter. His best-known publications are Annals of the Artists of Spain (1848; 2d cd., 1853), The Cloister Life of Charles V. (1852; 3d ed., 1853), and Velazquez and his Works (1855). A life of Don John of Austria, from his posthumous papers, is now (1882) in the press.
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