The gyro is set up to measure the rate at which its base is being turned about the Z axis.Ifthe base is mot turning,since the springs attached to the X axis are adjusted so that under these condition they are in balance.Turning the gyro assembly to the left, as shown by the arrow on the base, a force will be applied to the left at A and to the right at C.Recalling the rule for precession,the point B on gyro will move to the left and the point D will move to the right ,thus precessing the gyro about the Y axis and causing the indicated will depend upon how rapidly the base of the unit is turned.