American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 368
differ-ential galvanometers, wx and exare resistance boxes containingseparate coils for the artificial lineand condenser resistances. Theserheostats are cf the ^/a/ patternand are shown separately in Fig.237, WK and EK are smallbase boards on which are the keysused for conversation, and a 3-point… … WHEATSTONE REPEATER RELAV. 3i6 AMERICAN TELEGRAPHY. shown inserted in the center, the sets may be speedily disconnected from theground. WR and EE, Fig. 234, are the Wheatstone repeater relays. FIG. 237.
Telegraph
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