Page:Lectures on Ten British Physicists of the Nineteenth Century.djvu/63

 day were in Paris—Fourier, Fresnel, Ampére, Biot, Regnault. So William Thomson went to Paris, and worked for a year in Regnault's laboratory, where classical determinations of physical constants were being made. Partly as a consequence of this step, Thomson has always been very popular with the scientists of France. When resident in Paris he published in Lionville's Journal a paper on the "Elementary Laws of Statical Electricity," in which he examined the experiments and deductions of Sir. W. Snow-Harris. This investigator had made an experimental examination of the fundamental laws of electric attraction and repulsion, and his results were supposed to disprove the well-known simple laws of Coulomb. Thomson showed by pointing out the defects of Harris' electrometers that the results, instead of disproving these laws, actually confirmed them, so far as they went. From this examination dates Thomson's interest in electrometers, which led to the invention of the quadrant electrometer, the portable electrometer, and the absolute electrometer.

In 1846 the chair of Natural Philosophy in the University of Glasgow became vacant, and William Thomson was appointed at the early age of 22. I have heard it said that in the matter of appointments at Glasgow the principle of nepotism was powerful; in this case it was fortunate. Thomson's father was still the professor of mathematics, and remained so for three years longer; his brother, James Thomson, a few years later, became professor of engineering. At the same time Thomson was made editor of the Cambridge and Dublin Mathematical Journal (hitherto the Cambridge Journal). Among the contributors who supported him in this enterprise were Stokes, Cayley, Sylvester, De Morgan, Boole, Salmon, Hamilton, of whom only two now survive—Sir George Stokes, and Rev. George Salmon, Provost of Trinity College, Dublin.

While Thomson was a student at Cambridge, Joule made his investigations which determined the dynamical equivalent of heat. Thomson had made a special study of Fourier's Treatise on Heat, and had begun to apply his methods; consequently, on his return to Glasgow it was not long before he took up the