NA TURE 



385 



THURSDAY, SEPTEMBER 7, 1876 



SCIENTIFIC WORTHIES 

 IX. — Sir William Thomson. 



SIR WILLIAM THOMSON was born in Belfast in 

 June 1824. Hisfather, Dr. James Thomson, was a very 

 remarkable man. The family of Thomsons had for several 

 generations occupied a farm near Ballynahinch, in County 

 Down, Ireland ; but James Thomson, when quite a boy, 

 endeavouring all alone to understand the principles of 

 dialling, was led into the study of mathematics, for which 

 it soon appeared that he possessed an extraordinary 

 capacity. His father then permitted him to go to a small 

 classical and mathematical school at his native place, and 

 there he was soon promoted to be an assistant teacher. 

 Without ceasing to labour as a teacher for his own 

 support, he became a student in the University of Glas- 

 gow, attending there during the winter months, and 

 teaching at Ballynahinch during the summer. 



When he had nearly completed his fifth year at Glas- 

 gcv/, he was appointed Headmaster of the School of 

 Arithmetic and Geography at the Royal Belfast Academical 

 Institution, and subsequently Professor of Mathematics 

 in that Institution. In 1832 he was appointed Professor 

 of Mathematics in the University of Glasgow, and re- 

 moved thither with his family. He was the discoverer of 

 many improvements in algebra and in the calculus, and 

 in particular, he was the first to apply systematically 

 Horner's method of solving algebraic equations to the 

 arithmetical extraction of cube roots and higher roots of 

 numbers. He was also the author of several important 

 educational works which have come extensively into use ; 

 and besides excelling in science, he was highly accom- 

 plished in classical and in general literature. But he 

 is perhaps better remembered in Scotland for his suc- 

 cess as a teacher ; and those who were his pupils speak 

 with delight of his voluntary catechetical hours, in which 

 viva voce questions were proposed and rapidly passed 

 from bench to bench in a class of ready and enthusiastic 

 pupils. 



There are many who remember among the readiest 

 and the most enthusiastic, a little lad of eleven or twelve 

 years of age who could scarcely make himself seen 

 among his older class fellows. This was William 

 Thomson, who at that early age had entered the 

 University ; and who even then distinguished himself 

 greatiy for originality and high mathematical ability. 

 Having passed through Glasgow University he entered 

 St. Peter's College, Cambridge. In 1845 he graduated 

 as second wrangler and first Smith's Prizeman, and was 

 immediately elected a Fellow of his college. While he 

 was at Cambridge he was remarkable for his scholarly 

 attainments in science and in literature. He won the 

 Colquhoun, and was for some time president of the Cam- 

 bridge University Musical Society. 



After completing his undergraduate course at Cam- 

 bridge he went to Paris, and spent some time working in 

 the laboratory of Regnault, who was then engaged in 

 some of his most important researches. After the death 

 of Dr. Meikleham he became a candidate for the Chair 

 of Natural Philosophy in the University of Glasgow, ar^d 

 Vot. XIV.— No. 358 



was elected. Thus in 1846, at the early age of twenty- 

 two, he was appointed to the Chair which he has filled 

 with such distinction, and still holds. 



Sir W, Thomson's earliest contributions to physical 

 science were a defence of Fourier in answer to a charge 

 of erroneousness which had been brought against some 

 of the fundamental formulas of his harmonic analysis, and 

 a paper on " The Uniform Motion of Heat in Homo- 

 geneous Solid Bodies, and its Connection with the Mathe- 

 matical Theory of Electricity." These were written at 

 the age of seventeen. They were published in 1841 and 

 1 842 in the Caiiibridge and Dublin Mathematical yotirnal. 

 The latter paper is a very remarkable one : its spirit 

 runs through much of Sir William Thomson's subsequent 

 work. He points out in it the analogy between the 

 theory of the conduction of heat in solid bodies and the 

 theory of electric and magnetic attraction ; and, aiding 

 himself with this analogy, he makes use of known 

 theorems as to the conduction of heat in order to esta- 

 blish some of the most important theorems in the 

 mathematical theory of electricity. The method was 

 thoroughly original ; and later, taken in conjunction with 

 Faraday's admirable researches on electrostatic induction, 

 which led to the discovery of differences in the specific 

 inductive capacity of various substances, and to the 

 notion of conduction of lines 0/ force, it proved of the 

 highest value in the discussion of questions in electro- 

 statics and also in magnetism. As to the results obtained, 

 Thomson found, a few months after, that in some of 

 the most important he had been anticipated by M. 

 Chasles. Later he found that Gauss had given the same 

 general theorems shortly before Chasles independently 

 rediscovered them ; and, three years after, having heard 

 of a paper by Green, but long inquired for it in vain, he 

 found, on obtaining a copy of that paper, that all these 

 theorems had been discovered and published in the most 

 complete and general manner, with rich applications to 

 the theory of electricity and magnetism, as early as 1828. 

 This memoir of George Green, of Nottingham, was 

 printed privately, dedicated to his patron the Duke of 

 Newcastle, and it lay unread and unknown till 1845, 

 when Thomson obtained a copy, made known what 

 a mine of wealth it contained, and had it republished in 

 Crelle's Mathematical jfournal. 



Another very important paper written about the same 

 time, and published in the Cambrids;e and Dubli?i Mathe- 

 matical Journal iox 1842, was on the " Linear Motion of 

 Heat." It contained the foundation of the method of 

 evaluating absolute geological dates from underground 

 temperature, which he made the subject of his inaugural 

 address on his institution to his professorship in the Uni- 

 versity, and which we believe, foims a large part of the 

 subject of his opening address to the Mathematical Sec- 

 tion of the British Association. 



The papers referred to were followed by a paper 

 on the " Elementary Laws of Statical Electricity," 

 which first appeared in Liouville's Journal de Mathe- 

 matiques, in 1845, ^"d ^^^ translated and published 

 the same year in the Cambridge and Dublin Mathe- 

 matical Journal. Sir W. Snow Harris had under- 

 taken an experimental examination of the fundamental 

 i9,ws of electric attraction and repulsion ; and his 

 results, which received the Copley Medal of the Royal 



