Inertia

(in-ür's hah, or in-ür's he-a,) or VIS INERTIE. [L., inactivity; the effect of inactivity.) (Mech.) The pa ivene or inactivity of matter. This inertia, or perfect indifference to rest or motion, is a purely negative property of matter. A body when unsupported in mid-air does not fall to the earth in virtue of any inherent property, but because it is acted upon by the force of gravity. A billiard-ball gently pushed does not move more and more slowly, and finally stop, because it has any preference for a state of rest, but because its motion is impeded by the friction on the cloth on which it rolls, and by the resistance of the air. If all impeding causes were withdrawn, a body once in motion would continue to move for ever. Inez de Cas'tro. See CASTRO. [s. 483]