William Chauvenet, an American mathematician and astronomer, born in Milford, Penn., May 24, 1819, died at St. Paul, Minn., Dec. 13, 1870. He graduated with high honors in 1840 at Yale college, where his mathematical talents had already found an early recognition. He immediately became associated with Alexander Dallas Bache, his life-long friend and master in science, in delicate and important meteorological and magnetic observations at Girard college, Philadelphia. This connection continued till his appointment in 1841 to a professorship of mathematics in the navy. He promoted the establishment of the naval academy at Annapolis, the change in the system of educating naval officers, and the institution of the naval academy observatory, of which last he was at once appointed director. In 1859 he was called to the chair of mathematics and astronomy at Yale college and at the Washington university of St. Louis, Mo. Choosing the latter, he continued there till 18G8, when ill health obliged him to resign his chair, to the duties of which hud been added the chancellorship of the university. Many of his contributions to scientific knowledge were of great practical value, such as his methods of determining the longitude at sea, of rating chronometers, of great circle sailing charts, etc.

His "Treatise on Practical and Spherical Trigonometry" (2 vols. 8vo, Philadelphia, 1863) was declared by Prof. Bond of Harvard college to be "the most thorough and complete which had appeared in any country or language." His other works include "The Binomial Theorem Theory of Exponents and of Logarithms" (1843); "Plane and Spherical Trigonometry" (1850), a work following the methods of Gauss and Bessel; and "On Elementary Geometry" (1870).