but did not take a regular course leading to a degree. He had the genius of a mathematician, and his father was not slow to discover it. Accordingly he was sent when seventeen years of age to the University of Cambridge, where he became a student of St. Peter's College, the oldest foundation of that University (600 years). His undergraduate career at Cambridge extended over four years. In his first year he contributed a paper signed P. Q. R., to the Cambridge Mathematical Journal, in which he defended Fourier's Treatise on Heat from some criticisms made by Prof. Kelland of Edinburgh University. This paper was followed in the same journal by two others of still greater importance: "The uniform motion of heat in homogeneous solid bodies and its connection with the mathematical theory of Electricity" and "The linear motion of heat." In the former paper he points out the analogy between the theory of the conduction of heat in solid bodies and the theory of electric and magnetic attraction; and pursuing this analogy he makes use of known theorems about the conduction of heat to establish some of the most important theorems in the mathematical theory of electricity. The latter paper contains the foundations of the method which he afterwards applied to find limits to the age of the Earth. In his undergraduate career Thomson was well-known for his skill in boating; he was also president of the musical society. Probably he did not, as much as his rivals, concentrate his attention on the subjects which would pay in the final examinations; anyhow, he came out second wrangler. Although he was unsuccessful in the struggle for supremacy as determined by the blind adding of marks, one of the examiners declared that the senior wrangler was not fit to cut pencils for Thomson. In the subsequent more scientific test—the competition for the Smith prizes—he obtained the first place. He was immediately elected a Fellow of his college.
At this time (1845) the Analytical Society founded by Peacock, Herschel, and Babbage had accomplished its reform. But in Newton's University experimental investigation in physics had died out, the greatest mathematical physicists of the
