A long Autograph Letter, signed with his full name and address, to a London correspondent, Tuffen West, the engraver, referring to Smith’s studies of fresh water Diatomaceae and his drawings to be published by the Smithsonian, and suggesting exchanges of microscopic slides, hoping his correspondent can provide information on authentic specimens. 4 pp. (with one small illustration), 8 x 5 inches, in good condition, some paper adhering to fourth page. Gambier, Ohio [between 1853 and 1868]. Hamilton Lanphere Smith (1819 – 1903), American scientist, photographer, and astronomer. In 1848 Smith wrote “The World”, one of the first science textbooks written in America. Smith is best known for patenting the tintype photographic process, which popularized photography in America. He patented the great American tintype on February 19, 1856. Between 1853 and 1868 he was Professor of Natural Philosophy and Astronomy at Kenyon College, Gambier, Ohio. His correspondent is Tuffen West FLS, FRMS (1823-1891): artist of the microscopic, naturalist, and populariser of microscopy.