The upward movement of the piston having been effected by a rush of steam from the boiler upon its head, the steam was cut off and cold water run in upon it from a cistern. The steam was thus condensed by the water and a vacuum caused, and the piston was pressed down by the weight of the atmosphere—of course dragging down its end of the beam, and raising the pump-rod. The steam was then turned on again and pushed up the piston, and consequently the end of the beam also. Thus the engine continued to work, the turning of the cocks to admit steam and water being performed by an attendant.