St. John, Thomas M. (Thomas Matthew), b. 1865 · New York, T. M. St. John · leaf 93
he machine, a mark being madeupon it every time the armature of an inclosed eledlro-magnet is attracted. When the circuit is simplj closedfor an instant, a short line, representing a dot, is made. Registers are built both .single pen and double pen.In the latter case, as the record of one wire is… … Fig. 114. dots and dashes, it can be read at a glance, and as it isindelible, it may be read years afterward. Registers aremade for local circuits, for use in connedlion with relays,or for direcft use on main lines, as is usually desirable infire-alarm circuits. CHAPTER XV. THE ELECTRIC BELL AND…
Electricity
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