American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 581
s thermostats.In some systems also,two thermostats are used, conjointly, in a circuit, or in twocircuits; one being arranged to originate an alarm slightly in adv;»nee of the other;this to prevent false alarms that may be due to accidental contacts between the ter-minals of a thermostat. Other… … Bl-METALLIC THERMOSTAT. CHAPTER XXIX. POLICE SIGNAL TELEGRAPPI SYSTEMS. It lias been said,perhaps truthfully, that iu no other department of municipal gov-ernment, has there been so little progress as in the police department; for the old sys-tem, coming down from the time when watchmen patrolled…
Telegraph
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