Bohnenberger's machine illustrating the same tendency of rotating bodies. This consists of three rings, A, A', AJ, placed one within the other and connected by pivots at right angles to each other. The smallest ring, A2, contains the bearings for the axis of a heavy ball, B. The ball being set in rapid rotation, its axis will continue in the same direction, no matter how the position of the rings may be altered ; and the ring, AJ, which supports it will resist a considerable pressure tending to displace it.