American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 155
jeweled bearings is placed in a strong magnetic field, also like the siphon recorder,which coil tends to turn when a current passes through it. The coil carries a lightmetal pointer, the outer end of which, when the coil turns, moves over the scale;the scale being calibrated to indicate, in the…
Telegraph
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