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 the gyro will move to the left and the point D will move to the right. thus precessing the gyro about the Y axis and the causing the indicating needle to show a left turn. the rate of turn indicated will depend upon how rapidly the base of the unit is turned.