ERASMUS, an eminent German mathematician, was born in 1511 at Saalfeld, and was determined towards mathematics at the university of Wittenberg. Appointed to the mathematical chair in his alma mater, and favoured by the patronage of Albert, Duke of Prussia, he devoted himself to the prosecution of his favourite science. With patient and careful labour he began to produce a series of works of great practical utility. The first book of the Almagest, in Greek, with a Latin version and scholia, was issued in 8vo, 1549. A set of astronomical tables, formed from a comparison of the observations of Copernicus with those of Ptolemaeus and Hipparchus, and called, in honour of his patron Prutenicae Tabulae Celestium Motuum, was published in 1551. In 1554, the year after his death, there appeared a work entitled Primus Liber Tabularum Directionum, in which he extended Regionantius's Table of Tangents to each minute of the quadrant. There were also other calculations of his which were printed a considerable time after his decease.