carried in two smaller frames ff and f'f' which are free to turn about the precession axles P and P'. The axles of spin of the gyrostat wheels are ss and s's', and these axles project as shown at A and A'. The two gyrostat wheels spin in the direction of motion of the hands of a clock as seen from the outer ends of the axles of spin A and A', respectively. The precession axles P and P' are geared together by sectors of gear wheels G and G'. The frame FFFF is hindered from turning about the rocker-axis by the tables H, L, H' and L'; the tables H and L' extend backwards from the plane of the paper, and the tables L and H' extend forwards from the plane of the paper.
The action of this mechanism is as follows: Suppose side B' of the car body to be the heavier. The pull of gravity on this heavier side produces spin-momentum about the rail W as an axis, and this spin momentum is absorbed by the precessional motion of the gyrostat wheels, causing both ends of the axles of spin A and A' to move away from the reader in the figure. The unbalanced car, however, in tending to tip over (side B' overloaded), brings the projecting axle A into contact with the table H, the rolling action of the axle A upon the table H hastens the precessional motion, and this hastened precession raises the side B' and lowers the side B of the car-frame, as explained
