08/05/1875 Batchelor, Charles and Edison, Thomas Alva -- Lists and Inventories
(Exhibition. Philadelphia Centennial (1876)) Expositions, demonstrations, lectures; Multiple telegraphy (duplex, quadruplex); Automatic telegraphy [Marginalia by Batchelor, Charles]
[LB001]  Letterbook Series -- General Letterbooks: LB-001 (1875, 1877-1878)
[LB001003; TAEM 28:5]
Courtesy of Thomas Edison National Historical Park.