Instructions for testing telegraph lines and the technical arrangements of offices (1878)
Schwendler, Louis, 1838-1882 · London : Trèubner · leaf 182
un out. With each instrument a spare spring is generallyissued, tightly wound up, and tied together by a strongpiece of wire. It may happen that the spring in usebreaks, when it will be necessary to replace it by thespare spring, and as this is an operation by no meanseasy to perform, the following… … I70 OFFICE TESTING. Fig. 13 represents a perspective view of the spring drum. YVi. 13.
Telegraph · Telegraph lines
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