“ The registration is effected by the fall of a heavy pendulum, caused by the percussion of each step. The pendulum is forced back to a horizontal position by a delicate spring, and with each stroke a fine-toothed ratchet-wheel connected with it is moved round a certain length. The ratchet communicates with a train of wheels which work the dial-hands. In using the apparatus a measured mile or other known distance is walked and the indication thereby made on the dial-plate observed. According as it is too great or too small, the stroke of the pendulum is shortened or lengthened by a screw. ”