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SCIENCE 



[Vol. IV., No. 92. 



SIR WILLIAM THOMSON. 



Sir William Thomson's presence in this 

 country, the prominent part he has taken in the 

 two great scientific meetings held in America 

 this year, and his course of lectures at the Johns 

 Hopkins university, which has been attended 

 by professors and students of physics from all 

 parts of the country, will make a brief sketch 

 of the man and of his work especially welcome 

 at this time. 



Born at Belfast in 1824, he showed at a 

 very early age that the remarkable mathemati- 

 cal talent possessed by his father was to re- 

 appear in him with at least equal intensity. 

 At the University of Glasgow, where his father 

 held the chair of mathematics, he was, at the 

 age of eleven or twelve, already noted among 

 his much older classmates for his ability and 

 originality. At the age of seventeen he began 

 the splendid series of contributions to mathe- 

 matical physics which have formed so great 

 a factor in the progress of physical science. 

 These first papers, written at so early an age, 

 were of a nature to require a profound knowl- 

 edge of both mathematics and physics ; the 

 first being a defence of Fourier's mathematical 

 methods against some objections which had 

 been made to them, and the second relating to 

 the mathematical theory of heat and of elec- 

 tricity. 



A mere glance at the list of Sir William 

 Thomson's papers, as given in the Royal soci- 

 ety's catalogue, serves to convey some idea 

 of the diversity of mathematical and physical 

 subjects upon which he has written. Running 

 down the list in chronological order, and noting 

 only here and there a title, we find him dis- 

 cussing the equations of motion of heat, the 

 lines of curvature of surfaces of the second 

 order, electric images, terrestrial magnetism, 

 the theory of partial differential equations, the 

 economy of heating or cooling buildings by 

 currents of air, the dynamical theory of heat, 

 the dissipation of energy, the density of the 

 luminiferous ether, the theory of elasticit} T , the 

 calculation of a certain class of definite inte- 

 grals, the interior melting of ice, Leverrier's 



investigations on the motion of Mercury, the 

 protection of vegetation from destructive cold 

 at night, vortex atoms, — but we must make 

 an end somewhere. 



It is, of course, needless to say to the readers 

 of this journal that it is not upon the number 

 or diversity of his contributions to science that 

 Sir William Thomson's fame and pre-eminence 

 rest, but upon the fundamental importance 

 and epoch-making character of some of those 

 contributions. The article upon Sir William 

 Thomson in the Scientific worthies series (Na- 

 ture, 1876) gives a brief summary of some of 

 his most important researches and inventions. 

 We can here do hardly more than allude to a 

 few of them, referring readers, for a fuller ac- 

 count, to the above article, from which we 

 freely draw. Probably his most important 

 contributions to mathematical physics have 

 been his researches in electrostatics and mag- 

 netism. His first paper in this department of 

 physics, on the elementary laws of statical 

 electricity, written at the age of twenty-one, 

 demonstrated that results which had previously 

 been accepted were erroneous through a failure 

 to adopt necessary precautions in the experi- 

 ments upon which those results were based. 

 In this paper he also began the work of found- 

 ing the mathematical theory of electricity upon 

 Farada} r 's theory of electrical induction, — a 

 work which his later papers completed. In 

 this field, as in many others, his work was not 

 confined to mathematical, nor even to mathe- 

 matical and experimental research : an almost 

 equally notable part of it was the invention of 

 most important and ingenious electrometric 

 instruments, which have constituted the chief 

 means of establishing our present system of 

 practical electrometry. 



His contributions to thermodynamics have 

 also been of the highest and most fundamental 

 importance. He was among the first physicists 

 to thoroughly appreciate the effect, upon the 

 theory of heat, of Joule's determination of 

 the mechanical equivalent of heat ; and, in the 

 series of memoirs which he wrote upon thermo- 

 dynamics, he placed the science thoroughly 

 upon the new scientific basis of the doctrine 



