ELECTRIC CLOCKS

There are three distinct types of electric clocks, as follows: (1) Clocks in which the minute hand is advanced one minute, every minute, by a train of gears connected to a ratchet and pawl actuated by an electro-magnet. A high grade master clock of the pendulum type, conveniently located, has a contact-making attachment which it operates once a minute, sending out an electrical impulse through the wires to the secondary clocks. This impulse, by means of the mechanism described above advances the hand of the secondary clock. (2) Clocks run by the usual train of gears, escapement wheel or pendulum, and spring; but which are synchronized with the master clock once every hour, by means of an electro-magnetic device in the clock, actuated by impulses sent out over wires by the master clock. The springs of these clocks are periodically wound by a small electric motor. (3) Clocks operated by a small synchronous motor, geared to the hands. This motor is connected to the Alternating Current lighting system, the frequency of which is kept absolutely uniform by delicate governors on the generator prime movers at the power house. These governors are continually supervised by a master clock. The secondary clock therefore is always in synchronism with the master clock.