07.01.2019 Nikola Tesla U.S. Patent 512,340 U NITED S TATES P ATENT O FFICE. NIKOLA TESLA, OF NEW YORK, N. Y. COIL FOR ELECTRO-MAGNETS. SPECIFICATION forming part of Letters Patent No. 512,340, dated January 9, 1894. Application filed July 7, 1893. Serial No. 479,804. (No model.)