The body of the pump consists of a glass cylinder (outside diameter 7.3 cm, height 26 cm) with brass bases, fixed to the supporting shelf by means of the suction pipe that is immersed in the basin and is closed at the base of the pump body by a valve that opens only upwards.
The piston is composed of about ten cloth disks held closely together by two brass disks; a brass pipe with a valve, which like the others opens only upwards, brings into communication the two parts into which the piston divides the pump body on passing through its centre.
At the top of the pump body there is a glass, held by the same brass pipe that puts it in communication with the pump body; the rod connecting the piston to the lever that moves it also passes through this pipe.
By slightly rotating the lower part of that rod, the valve of the piston is closed.
The water sucked from the basin can return to it through two different paths by which it reaches different heights, in one being raised to the glass above the pump body and in the other to the one placed on top of the exhaust pipe.