BENJAMIN SILLIMAN (1816-1885), American chemist and physicist, son of the preceding, was born in 1816 at New Haven, Connecticut, and educated at Yale College, where he graduated in 1837. He then became assistant to his father in chemistry, mineralogy, and geology, work-ing in his laboratory at the college, and pursuing original investigations. He began teaching in the laboratory soon afterwards. The school thus informally established was shortly afterwards recognized by a formal act of the cor-poration of the college, and ultimately developed into the Sheffield Scientific School of Yale College. In 1838 he became associate editor with his father of the American Journal of Science and Arts, and he continued in the editorship of the journal until the close of his life, Prof. J. D. Dana (his brother-in-law) having joined him in 1846. In the winter of 1845-46 he gave a course of lectures on agricultural chemistry in New Orleans, which is believed to have been the first course of lectures upon that subject ever given in the United States. In 1849 he was appointed professor of medical chemistry and toxicology in the medical department of Louisville university, Louisville, Kentucky, which position he held for five years. In 1854 he succeeded his father as professor of chemistry, and continued to give instruction in this science, first in the academical and afterwards in the medical department of Yale College, until his death in 1885. In 1853 he was connected with the exhibition at the Crystal Palace in New York, having charge of the departments of chemistry, geology, and mineralogy. As a result of this work he edited a large quarto volume, The World of Science, Art, and Industry (1853), followed in 1854 by The Progress of Science and Mechanism. He also published in 1846 First Principles of Chemistry, a text-book which had a wide sale and passed through three editions. In 1858 he published a manual of physics entitled First Principles of Physics or Natural Philosophy (2d ed. 1861). In 1864 and again in 1867 and 1872 Silliman visited California, being engaged in professional work connected with various mines and in mineralogical and geological ex-plorations. Still later he made several visits to the mining regions of the western States and Territories, and the results of his observations formed the subjects of numerous scientific papers. In 1874, the centennial anni-versary of Priestley's discovery of oxygen, he delivered at Northumberland, Pa., where Priestley had resided during the later years of his life, an historical address on " American Contributions to Chemistry," which he afterwards expanded into a considerable volume.