What kind of clock mechanism did Leonardo da Vinci design with separate displays for hours and minutes?

Leonardo da Vinci designed a water-powered clock with separate displays for hours and minutes.

In his notebooks, Leonardo developed a water clock in which controlled water flow operated a mechanism that measured time. One notable design separated the indication of hours from the indication of minutes, reflecting his interest in making timekeeping more precise and visually legible. The system used tanks, floats, and mechanical transmission rather than a modern spring or pendulum.

Water clocks were ancient devices, but Leonardo examined them with Renaissance engineering methods. He studied how water could move steadily, how floats could translate level changes into motion, and how gears could display the result. These investigations connected hydraulics with clockwork.

Leonardo’s clock designs were proposals and studies, not mass-produced timepieces. They also predate the pendulum clock by more than a century: Christiaan Huygens introduced the first successful pendulum clock in 1656. Thus Leonardo’s design belongs to the history of hydraulic timekeeping, not modern mechanical horology.