Mill Wheel and Double Timber Trestle for a Watercourse
Red-chalk mill wheel with front view, plan and profile of a double beam-frame carrying water
The sheet groups a red-chalk mill wheel at the upper right with several views of a timber trestle: a front view marked 8 braccia, a plan of the same marked with its foundation, and a labelled profile. The profile note explains that the double trestle a–b is meant for waters of the fourth motion, running below and above, 8 braccia wide and one braccio deep. Together the drawings work out how a framed timber channel carries and drives water at a mill.
On this page
Mill wheel
At the upper right a mill wheel is sketched in red chalk, its hub and spokes bound into a supporting timber frame. It is the driven element served by the timber water channel drawn below.
Trestle: front view, plan and foundation
The right-hand study gives a front view of the timber trestle marked 8 braccia, and the left-hand study its plan, marked with the foundation. The pair sets out the built structure that carries the water channel.
Double trestle a–b for waters of the fourth motion
The profile is labelled a and b. Leonardo notes that this double trestle a b is to be for waters of the fourth motion, both below and above, 8 braccia wide and one braccio deep.