Perpetual motion pump

In a sheet entirely dedicated to water lifting systems there is this unique study of a perpetual motion pump. An interesting feature is the feeding device that uses a hydraulic wheel equipped with three boxes, which are filled through a pair of pumping pistons driven by cams mounted on the axis of the wheel itself. Leonardo pays a great deal of attention to the design of this machine, looking at some elements in great detail, such as the two pumps and the system for emptying the boxes. He annotates a 100-pound weight on each of the two lead pistons, 200-pound weight on the compression chamber, while in the margin of the sheet he records that the water contained in the tube weighs 20 pounds. Remarkable is also the detail of the solution adopted for emptying the boxes, a door whose shutting mechanism is operated by a spring and a weight. When, during rotation, the weight rests on a plane, the door opens, letting the water out; as the rotation continues, the weight is dropped from the plane, closing the door.