Telegraphy and how to learn it; with brief chapters on elementary science, embracing various kinds of electricity, electrical measurements, thermo-frictional electricty, batteries, magnets and magnetism (1901)
Frederic, Wilson. [from old catalog] · Chicago, The Henneberry co · leaf 89
y, can then with advantagebegin, each student having an instrumentconnected at his own end of the wire, andall communications between them necessa- 86 TELEGRAPHY. rily being made by telegraph. According tothe length of the line between the two in-struments, two or more cells of battery, ar-ranged… … necting with the earth at each end, G. G.For wires of but a short distance in lengththe return wire is the best; for out-doorlines of more than a few hundred feet inlength, use ground wires, as earth connec-tions are called. To make a ground wire, connect a wireto a plate or sheet of metal, copper,…
Telegraph
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