11/02/1885 Edison, Thomas Alva to Preece, William Henry
(Moore, Michael Miller) International business operations; Research and development; Multiple telegraphy (duplex, quadruplex)
[LB021]  Letterbook Series -- General Letterbooks: LB-021 (1885-1886)
[LB021117A; TAEM 83:340]
Courtesy of Thomas Edison National Historical Park.