Leonardo da Vinci designed a hydraulic saw that used water-powered motion to cut wood.
His drawings show a sawmill mechanism in which a waterwheel supplied rotary power. Gears and connecting parts transformed that rotation into the back-and-forth movement required by a saw blade. The arrangement could also coordinate the movement of timber, making the cutting process more continuous than hand sawing.
Water-powered sawmills existed before Leonardo, so he should not be credited with inventing the general concept of a hydraulic sawmill. His importance lies in the detailed study and refinement of mechanical systems. His notebooks frequently show how rotary movement could be converted into linear or reciprocating motion.
The device is sometimes confused with a chain pump, another water-related machine studied by Leonardo. A hydraulic saw uses water power to perform cutting, whereas a chain pump lifts water from one level to another.