This model illustrates a mechanical system for operating four hydraulic pumps with the motion of a single shaft. The model is very elegant and rich in architectural detail. It represents a round, inlaid platform on which four wells are fixed. At the center of the platform stands a column supporting a crank, moved by a pair of horses bridled to two poles. The crank's rotary motion is transformed into an alternating motion by a pair of rocker arms or balance beams that activate four pumps to draw water from the wells.

The model represents a later interpretation of the patent for hydraulic apparatus granted to Galileo by the Most Serene Republic of Venice in 1594.