I3ACHE, ALEXANDER DALLAS, 1806-67, an American physicist; b. in Philadelphia. He was great-grandson of Benjamin Franklin; graduated at West Point, as lieutenant of engineers, in 1825, remaining some time in the academy as a teacher. He was employed under col. 'rotten on the fortifications at Newport, where he married Nancy Clarke Fowler. B. was professor of natural philosophy and chemistry in the university of Pennsylvania, and an early member of the Franklin institute, the journals of which gave an account of his scientific labors. In company with others he built an observa tory in which, for the first time in the United States, the periods of the daily variations of the magnetic needle were fully determined, and other interesting observations made. In 1836, lie became president of the trustees of Girard college, and visited Europe to examine educational systems for the information of the board, who were about to arrange the plan of the institution. His report in 1838 was of great value in suggesting improve ments in our educational system. Before the college was organized, B. established a system of free education in Philadelphia, serving for a time gratuitously, at the same time assisting the British association hi the examination of meteorological and magnetic phenomena. In 1842, he returned to his professorship in the university, and in 1843 was
appointed successor to Hassler in the U. S. coast survey. This important service he reorganized and brought to its present recognized efficiency. He was also superintendent of weights and measures, regent of the Smithsonian insti tution, vice-prtsident of the U. S. sanitary commission, received the degree of LL.D. from several colleges, medals from foreign governments and learned bodies, -was presi dent of the American philosophical society, president of the association for the advance ment of science, and associate of many important scientific institutions at home and abroad. He gave $42,000 to the national academy of science for the promotion of its object. His important works are: Obsercations at the Magnetic and Meteorological 0.5ser ratory of Girard College, reports on weights and measures, and various essays in the Proceedings of the Association for the Advancement of Science.