I. James Biythe

James Biythe, an American chemist, born in Philadelphia, Feb. 22, 1803, died there, June 15, 1852. He received the degree of M. D. at the university of Maryland, and was successively professor of chemistry in Washington medical college, Baltimore, the medical college at Cincinnati, the Franklin medical school of Philadelphia, and the university of Pennsylvania. For several years he was chemical and geological assistant in the surveys of Virginia and Pennsylvania. He published papers in the scientific journals, and was one of the editors of the last American reprint of Turner's "Chemistry."

II. William Barton

William Barton, an American physicist, brother of the preceding, born in Philadelphia in 1805. He first lectured on science in the Maryland institute in 1827, and in 1829 succeeded his father, Dr. P. K. Rogers, in the chair of natural philosophy and chemistry in William and Mary college. From 1835 to 1853 he was professor of natural philosophy and geology in the university of Virginia. In 1853 he removed to Boston, where he has since resided. He examined the region of the mineral springs of Virginia, and analyzed their waters; and in 1835 he organized the state geological survey, at the head of which he remained till it was discontinued in 1842. In 1862 he delivered a course of lectures before the Lowell institute on the application of science to the arts; and from 1862 to 1868 he was president of the Boston institute of technology. He is the author of a treatise on the "Strength of Materials" (1838), "Elements of Mechanical Philosophy" (1852), and numerous scientific papers. In 1875 he was elected president of the "American Association for the Advancement of Science" for the ensuing year.

III. Henry Darwin

Henry Darwin, an American geologist, brother of the preceding, born in Philadelphia in 1809, died in Glasgow, Scotland, May 28, 1866. He became professor of physical sciences in Dickinson college, Carlisle, in 1831, and afterward professor of geology in the university of Pennsylvania, which office he held for many years. He made a geological survey of the state of New Jersey, of which he published a report and map in 1835, and a final report in 1840. From 1836 to 1855 he was engaged in the survey of Pennsylvania, publishing during the first years annual reports of progress. His final report, in two large vols. 4to, with numerous drawings and illustrations, and an atlas (Edinburgh, 1858), is especially valuable in the departments of structural and dynamic geology. In 1857 he was appointed regius professor of geology and natural history in the university of Glasgow, Scotland. He contributed many important papers to the transactions of philosophical societies, and was one of the editors of the Edinburgh "New Philosophical Journal." He published a geological map of the United States and a chart of the arctic regions in the "Physical Atlas," and in conjunction with W. and A. K. Johnston of Edinburgh a geographical atlas of the United States.

IV. Robert Empie

Robert Empie, an American chemist, brother of the preceding, born in Baltimore in 1814. He took the degree of M. D. at the university of Pennsylvania, and in 1844 was appointed to the chair of chemistry in the university of Virginia, which he held till 1852, when he succeeded his brother Prof. J. B. Rogers as professor of chemistry in the university of Pennsylvania. He was associated with the latter in preparing the amended edition of Turner's "Chemistry," and has since edited the American reprint of Lehmann's "Physiological Chemistry." He has been for many years dean of the medical faculty of the university of Pennsylvania.