Two drawings of a fountain, designed as an Ionic column on a basin. In the larger, on the capital stands a naked man bent forward under the weight of a huge basket; water is squirted from a pipe in his hands into the basket. The smaller has a decorative bowl on the capital.

This is one of two fragments probably cut from a single sheet (the other is RCIN 912691), with designs for a ‘Heron’s fountain’. In this hydraulic curiosity (named after the Greek mathematician Heron of Alexandria), a reservoir of water emptying by gravity into a lower chamber sends a small fountain of water back into the upper reservoir. The device gives the impression of being a perpetual motion machine, though eventually the reservoir empties and the fountain stops.

The designs offer a rare glimpse of Leonardo thinking as a sculptor in a context other than an equestrian monument. Their scale is hard to determine: they were probably table fountains to be cast in bronze or silver, but the columns seem monumental in conception and they could have been full-scale fountains for a garden.