Electrical instruments and telephones of the U.S. Signal corps
A U.S. Army Signal Corps technical manual issued by the Government Printing Office in Washington in 1911, describing field telegraph and telephone apparatus for military signal operators. The single plate is a line-drawn circuit diagram labeled East and West, with coils, relays, keys, and crossing wire runs rendered in thin uniform strokes on white ground, useful as engineering schematic texture or diagrammatic line art.
