Modern practice of the electric telegraph : a handbook for electricians and operators (1874)
Pope, Frank L., 1840-1895 · New York : D. Van Nostrand · leaf 176
MANUFACTURER OF TELEGRAPH INSTRUMENTS, SOLE MANUFACTURER OF THE ORIGINAL CELEBRATED cc BOSTON HE3LA jy All Instruments and Materials used in furnishing and working TELEGRAPH LINES, including Registers, Relays, Main Sounders, Local Sounders,Keys, Switches, Cut-outs, Galvanometers, Repeaters,…
Telegraph
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