[Illustration: DAVEY'S PENDULUM FOR SYNCHRONIZING CLOCKS.
W, friction wheel attached to pendulum. L gives no impulse except
when the electro-magnet is excited. K, lever and weight lifted by
electro-magnet, E. A, open contact completed by pendulum each
swing. B, battery. R, ratchet wheel and pawl. M, lever fixed at
top. L, weight at end of bell crank lever, which drives pendulum
once each minute, being raised by the electro-magnets.]
At the recent meeting of the Institution of Mechanical Engineers,
Dublin, Mr. Davey, of Leeds, spoke of synchronizing mechanisms. He had
occupied some of his spare time in attempting to synchronize clocks
from a standard clock. The problem is similar to the present one,
except that it is rough-and-ready, compared to the present one. He had
a novel electrical pendulum, to drive a seconds pendulum by
electricity. Electrical clocks are notoriously bad timekeepers; on
account of variation in the strength of the electrical current, the
battery falls off. He had constructed an electric clock having a
seconds pendulum, and recording an impulse once a minute. On the
pendulum he had a little ratchet wheel, R, having thirty teeth. The
pawl was connected with a lever, M, fixed at the top. On the face of
the wheel a little pin rotates with the wheel. On the side of the
clock case was a contact maker, which closed the circuit by the pin on
the ratchet wheel, R, once every minute. The weight was lifted by the
electric current, and by its fall gave an impulse to the pendulum. The
pendulum was a free swinging pendulum for 59 sec., and the increase of
the arc could scarcely be detected.
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