Second

Second is one-sixtieth part of a minute, and is the unit of time universally adopted. It is fundamentally derived from the time which elapses between two suecessive transits of a star, this being the time taken by the earth to exactly complete one revolution on its axis, and being known as one sidereal day. The length of a pendulum which beats seconds varies in different places, owing to the variations of gravity. Hence, if the standard or length were lost, it could always be reconstructed. [PENDULUM.] A second is also used as a measure of angles, it being one-sixtieth part of one angular minute, which is, again, one-sixtieth of a degree.