Spon, Ernest, Haldane, Robert, Lock, Charles G. Warnford (Charles George Warnford), 1853-1909 · London ; New York : E. & F.N. Spon · leaf 213
mployed at the central ofiice or other receiving station, to transmit a signal without employing a battery, as in the case of the ordinary Gower telephone. The employment of bifurcated or double acoustic tubes obviates the necessity for having a separate instrument as receiver, and thus enables the… … (c) Fig. 118, making the bell-case act as bells, yet sufficient for the purpose as switch-board, a b are the line ter- II, tube; hj brass screw, Fisf. 116: 0 'J
Workshop recipes · Technology · Industrial arts
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
