MALLET, John William, chemist, born in Dublin, Ireland, 10 October, 1832. He was graduated at Trinity college, and studied chemistry at the University of Gottingen, Germany, where he received the degree of Ph.D. for his researches on the tellurimn ethers in 1852. Soon afterward he came to the United States, and was called to Amherst, where, during 1854-'6, he was assistant professor of analytical and applied chemistry. He was then given the chair of chemistry in the University of Alabama, where he remained until the beginning of the civil war, and was also associated in the chemical work of the geological survey of Alabama. Professor Mullet took an active part in the war and attained the rank of colonel in the Confederate army. He became professor of chemistry in the medical department, of the University of Louisiana in 1865, and later engaged in the iron business near Vicksburg, Mississippi He accepted in 1867 the professorship of analytical, industrial, and agricultural chemistry in the University of Virginia, which chair in 1872 became that of general and industrial chemistry and pharmacy. Professor Mallet continued this relation until 1883, when he became professor of chemistry and physics in the recently organized University of Texas, and the equipment of these departments was selected by him, but he resigned a year later to accept a similar chair in Jefferson medical college, Philadelphia. In 1885 he returned to the University of Virginia as professor of genera[ and industrial chemistry and pharmacy, which post he still (1888) holds. Professor Mallet's researches in pure chemistry include valuable investigations on the atomic weights of aluminium and lithium, and improved methods of analysis. In the direction of mineral chemistry he has accomplished much, not only by making analyses of new minerals, but also in the " Laboratory Communications" from his students that have been published by him, separations of rare earths have been indicated. His specialty is industrial chemistry or chemistry applied to the arts and manufactures, and in this branch he has probably no superior in the United States. His extended knowledge of this subject led to his being called to lecture on the " Utilization of Waste Products" in 1879-'80 at Johns Hopkins university, and at that time he published fit the "American Chemical Journal" a review of the " Progress of Industrial Chemistry" for the decade of 1870-'80. At the request of the National board of health he undertook an elaborate investigation as to the chemical methods in use for the determination of organic matter in potable water, with a comparative study of the water-supply of different localities in the United States. This work has taken high rank in the literature of water analysis, and was published by the board in its annual report for 1882. In 1880 he was elected a fellow of the Royal society of London, and in 1882 he was president of the American chemical society. The honorary degrees of M.D. and LL. D. have been conferred on him. His publications have been entirely in the line of his profession, and have been confined to scientific journals.