A point in any body about which all the parts are in equilibrio; so that if the body be suspended or supported by this point, it will remain in any position in which it may be placed. The centre of gravity of any plane may be found mechanically as follows: suspend the plane by a point in or near its perimeter, and when it is at rest, draw across it a vertical line, passing through the point; suspend it in like manner by another point, and draw a vertical line as before; the intersection of these lines is the centre of gravity.