THOMSON, Elihu, electrician, born in Manchester, England, 29 March, 1853. He came to this country in 1858, and was graduated at the Central high-school in Philadelphia in 1870. He studied chemistry in an analytical laboratory, but was soon called to assist in the chemical department of the high-school, which place he held until 1876, when he was made full professor of chemistry and physics in that institution. Meanwhile, in 1875, he had been chosen professor of chemistry in the Artisan's night-school in Philadelphia, and during the winter of 1876-'7 he began a series of lectures on electricity at the Franklin institute. For several years he studied very closely the subject of electricity, with its special application to artificial illumination, and in 1880 he was appointed electrician to the American electric company of New Britain, Connecticut He at once devoted himself to inventing, and nearly 200 patents relating to arc lighting, incandescent lighting, motor work, induction systems, and similar applications have resulted. For the development of these inventions the Thom-son-Houston electric company was organized, and located its plant in Lynn, Massachusetts Professor Thomson has also invented the system of electric welding, which he placed in the hands of a corporation, and it has now become an established industry. He is a member of the American philosophical society and the American academy of arts and sciences, and vice-president of the American institute of electrical engineers, and has contributed technical papers to the societies of which he is a member.