PEIRCE, Benjamin (1809-1880), mathematician and astronomer, was born at Salem, Massachusetts, 4th April 1809. Graduating at Harvard College in 1829, he became mathematical tutor there in 1831 and professor in 1833. He had already assisted Bowditch in his translation of the Mécanique Céleste, and now produced a series of mathematical text-books characterized by the brevity and terseness which marks all his work and made his teaching unattractive to inapt pupils. To young men of real talent, on the contrary, his teaching and warm personal interest in their work were of the greatest advantage, and he holds a most honourable place in the development of American mathematics. After Bowditch’s death in 1838 Peirce stood at the head of American mathematicians; but the first work that gave him a wider fame was his computation of the general perturbations of Uranus and Neptune (Proc. Amer. Acad, 1848). In 1849 he became consulting astronomer to the American Nautical Almanac, and for this work he prepared new tables of the moon (1852). Another piece of important astronomical work was his discussion of the equilibrium of Saturn’s ring, in which he showed that a fluid ring was necessarily unstable as well as a solid one. From 1867 to 1874 he was superintendent of the coast survey; in 1857 he published his largest and most characteristic work, the System of Analytical Mechanics. He himself, however, seems to have thought most of his Linear Associative Algebra (lithographed privately in a few copies, 1870; reprinted in the American Journ. of Math., 1882). His death took place at Cambridge, United States, on 6th October 1880.