There being some peculiarities in the construction of the Clock lately set up in this room, which may prove to have considerable influence on the performance of such instruments, and also on their cost and duration, it is presumed that a short notice of them, together with a few preliminary observations, may not be deemed uninteresting to the Society.

An eminent philosopher, in a work recently published, has defined a clock to be “nothing more than a piece of mechanism, for counting the oscillations of a pendulum.” This definition cannot be considered as complete, as besides having to register the oscillations of its pendulum, a clock has to communicate successive impulses to it, to enable it to overcome the friction of its suspension, and the resistance of the air. If a maintaining power were not exerted by the clock, the pendulum would soon be brought to a state of rest.