Operator
An 1874 New York trade catalogue of telegraph instruments, aimed at buyers and students of telegraphy, with its sample instruments drawn in fine engraved detail. The four pictures show a private line sounder set, a student's outfit with a coil battery, a priced first-class outfit, and a line diagram of a telegraph key and electromagnet with batteries. A designer could draw on their dense hatched shading, ornate brass fittings, and the plain schematic linework of the wiring diagram.
