American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 225
ar to those of the Wheatstone relay shown and described, pages 303, 315, 317 ; themain difference being that in this form the electro-magnets lie horizontally, length-wise, with pole-pieces facing, and the armatures are vertical, lengthwise, the lowerends of the armatures being loosely inserted in… … THE POLAR DUPLEX. <S7 FIG. I54rt. FIG. 1543.
Telegraph
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