The pendulum swings for many cycles
when the gyroscope is not spinning. The spinning gyroscope will
damp out the motion of the pendulum in a quarter of a cycle.
The gyroscope's spin axis is vertical, and its precession axis is
horizontal and in the plane of oscillation of the pendulum. The
precession of the gyro is opposed by a torque applied to the inner
gimbal by the hinged arm visible in the photo at the right.
Friction in the hinge is adjustable by a thumbscrew.
