Page:Popular Science Monthly Volume 10.djvu/371

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THIS distinguished physicist and mathematician was born in Belfast, in June, 1824. His father, Dr. James Thomson, was a man of large capacity and culture, who studied in the Glasgow University, became head-master of the Belfast Academical Institution, and in 1832 was appointed Professor of Mathematics in the University of Glasgow. He made various improvements in mathematics, and wrote books upon education. William passed through the Glasgow University early, and then entered St. Peter's College, Cambridge, from which he graduated as second wrangler in 1845, and he was immediately elected Fellow of his college. He afterward went to Paris, and worked in the laboratory of Regnault. In 1846, at the early age of twenty-two, he was appointed Professor of Natural Philosophy in the University of Glasgow, a position which he has filled with distinction, and still occupies.

Sir William Thomson's earliest contributions to physical science were on the subject of heat, the laws of its motions being treated mathematically. A remarkable paper on "The Uniform Motion of Heat in Homogeneous Solid Bodies," written at the age of seventeen, was full of original conceptions, but it was afterward found that Thomson had been anticipated in his ideas by Gauss, Chasles, and George Green, of Nottingham. In 1842 he published an important paper on "The Linear Motion of Heat," which contained a method of deriving % geological dates from underground temperatures, a subject which he treated in his inaugural address, in entering upon his professorship at the university.

It will be impossible here to give any account of the numerous contributions to science made, by Sir William Thomson, as they were generally of so mathematical a cast as to be unintelligible to ordinary readers. His papers on "Electro-Statics" and on "Magnetism" were collected and published in 1872, in a valuable volume of six hundred pages. The more interesting aspects of his work have been well described by a writer in Nature, and we cannot do better than to quote some passages from his notice:

"His electrostatic researches led Thomson to the invention of very beautiful instruments for electrostatic measurement. The subject of electrostatic measurement occupied much of his attention from the very earliest, when he was obliged to call attention to the defects of the electrometers of Snow Harris. His labors in this direction have produced the quadrant electrometer, which is employed for all kinds of electric testing in telegraph construction, and for the registration of atmospheric electricity at Kew Observatory; the portable electrometer, for atmospheric electricity and for other purposes, in which the extreme sensitiveness of the quadrant-electrometer is not required; and the abso-