Simon Newcomb. 291 



He returned to the United States in 1852 and was followed in 

 the succeeding year by Simon Newcomb, who, like his father, 

 had been a teacher in Canada. For the next two years the 

 young Newcomb taught school in Maryland and, while thus 

 engaged, awakened the interest of Joseph Henry, the Secretary 

 of the Smithsonian Institution, by means of a mathematical 

 paper which was submitted to him. Henry secured for the 

 young teacher an appointment as a computer in the IT. S. 

 Nautical Almanac, which was then published at Cambridge. 

 While here he became a student in the Lawrence Scientific 

 School, which completed his academic life until he returned to 

 it as a Professor of Mathematics and Astronomy at Johns 

 Hopkins University. This chair he held from 1884 until 1894. 



While occupying the position of a computer in the Nautical 

 Almanac Office, Newcomb published a paper on the orbits of 

 a number of the asteroids which at once secured for him a 

 world-wide reputation as a master in this difficult field of 

 research and in which he was destined to lead his contem- 

 poraries. His exceptional merits were quickly recognized and 

 lie was given, in 1861, an appointment as a professor of 

 mathematics in the U. S. Naval Academy with an assignment 

 to duty in the Naval Observatory. This title he held until 

 1877, when he became Senior Professor of Mathematics. He 

 retired in accordance with the law at the age of sixty-tw T o, in 

 1897. During this period of twenty years Professor Newcomb 

 was Director of the American Ephemeris and Nautical 

 Almanac. 



While connected with the Naval Observatory, Newcomb, in 

 pursuit of his favorite study, advanced observational science in 

 a remarkable degree. In order to secure better values of the 

 masses of Uranus and Neptune, essential to his great project 

 of perfecting the tables of the Solar System, it was necessary 

 to have more perfect observations of the satellites of these two 

 planets, and there were no telescopes in existence adequate to 

 this end. This prompted him to a careful study of the best 

 type of instrument for such observations, together with the 

 probable limitations of the contemporary optical art, finally 

 fixing upon a refractor of twenty-six inches aperture, for the 

 construction of which he obtained a grant from Congress. 

 This, the first of the great modern telescopes, was completed 

 in 1876 and was made famous in August of the following year 

 by the discovery of the two satellites of Mars by Professor 

 Asaph Hall. Meanwhile, Newcomb had observed the satellites 

 of the two most remote planets of our System and employed 

 his results in perfecting the tables for Uranus and Neptune, 

 which have been used by all astronomers from the moment of 

 their first appearance. The knowledge and experience acquired 



