Orbital-trestle crane and the yearly water cycle
A red-chalk crane on wheels with a backup rope, and a note balancing rising and falling water
A red-chalk drawing at the centre of the sheet shows a crane mounted on a wheeled trestle, described in the note as a crane on an orbital trestle. The accompanying text advises fitting the hoist with a strong rope and a second, slacker one alongside, so that if the strained rope breaks the other keeps working. A separate line above reflects on the water cycle, equating over a year the water that rises with that which descends in rivers and air.
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A crane on an orbital trestle with a backup rope
The hoisting arm is to carry a rope built to endure the strain, with a second, slacker rope in a similar place, so that if the strained one breaks the other remains at the same task. The drawing shows the trestle structure resting on small wheels.
The yearly balance of rising and falling water
The note reasons that, once a year, the quantity of water that rises equals the quantity that descends through the rivers and the air, an early statement of the water cycle.