ALEXANDER., John Henry, scientist, born in Annapolis, Maryland, 26 June 1812; died in Baltimore, Maryland, 2 March 1867. He was graduated at St. John's College in 1826, and studied law, but turned his attention to science. His first work was in engineering, and having submitted to the legislature a plan for the survey of Maryland, in connection with the geological survey, he became in 1834 the topographical engineer of his state. As such he was engaged until 1841, and during the intervening years he regularly prepared the annual reports. The opening of various iron and coal deposits was promoted by these reports, and by his efforts capital was enlisted in the working of the mines. As an authority on standards of weight and measure, his opinion was highly regarded, and he was associated in much of the work conducted under the direction of the coast survey during the superintendency of Hassler and Bathe. In 1857 he was sent to England by the national government as delegate to the British commission on decimal coinage. His views on this subject were highly appreciated in this country, and he was about to be appointed director of the mint in Philadelphia when he died. Ha served on various government commissions, and his numerous reports are of great value. At various times he was professor of physics in St. James's College, Maryland, in the University of Pennsylvania, and in the University of Maryland. He was a member of many scientific societies, among them the American philosophical society of Philadelphia and the American association for the advancement of science, and he was one of the incorporators of the national academy of sciences. His published papers appeared principally in the "American Journal of Science and Arts." He edited three editions of Simms's" Treatise on Mathematical Instruments used in Surveying, Levelling, and Astronomy" (Baltimore, 1835, 1839, and 1848), and also Simms's " Treatise on Levelling "(1838). Among his larger works are "History of the Metallurgy of Iron," Parts 1 and 2 (1840-'42), and "Universal Dictionary of Weights and Measures, Ancient and Modern " (1850). He also wrote several collections of religious verse, of which "Introits" (Philadelphia, 1844) and "Catena Dominica" (1854) were published. Several works in manuscript remained unpublished at the time of his death, of which the most important was "A Dictionary of English Surnames" (12 vols., 8vo). See "Biographical Memoir of John H. Alexander," by J. E. Hilgard, in vol. 1 of the "Biographical Memoirs" of the national academy of sciences; also "Life of J. H. Alexander," by William Pinkney (1867).