SYLVESTER, James Joseph, English author, born in London, England, 3 September, 1814. He was graduated at Cambridge, became a professor of natural philosophy at University college, London, and was made a member of the Royal society in 1839. He came to this country and held the chair of mathematics in the University of Virginia in 1841-'2, and was appointed to a similar professorship at the Royal military academy, Woolwich, in 1855. He was professor of mathematics at Johns Hopkins university, Baltimore, in 1876-'83, and in December, 1883, was elected Savilian professor of geometry at Oxford. He is a member of many learned societies both in Europe and this country, received the medal of the Royal society in 1860, and the Copley medal in 1880, and has been the recipient of honorary degrees from various colleges. He was the founder and the first editor of the "American Journal of Mathematics," is the author of a large number of important scientific memoirs, 112 of which, published previous to 1863, are in the Royal society's index of scientific papers. He has given a theory of versification in a volume entitled "Laws of Verse" (London, 1870); has invented the plagrograph, an instrument which, in addition to altering the magnitude of an object, possesses the property of rotating its image through any desired angle; the geometrical fan, which has been applied to the construction of a cheap astronomical spectroscope; and other geometrico-mechanical instruments. He has developed a method of transferring circular into rectilinear or parallel motion, based upon the discovery of a French engineer, thereby adding immensely to the resources of the mechanician. In December, 1885, Professor Sylvester made known his theory of reciprocants, which, it is claimed, more than doubles the resources of algebra.