A Float-and-Weight Lifting Device that Works Underwater
A mechanism whose parts b c and n m are fixed to a shaft while d e and o p move, using buoyancy underwater to raise a pole and open a vessel
The lower fragment describes a mechanism built on a shaft, drawn in plan and elevation: the parts b c and n m are fixed to the shaft and move up and down with it, while d e and o p are movable. In the second figure the motion is reversed, exploiting buoyancy: o p descending through the air acts as a heavy body, while n m held underwater acts as a light body, raising a, opening the device above and closing it below, so that n m is able to lift the whole pole and open the vessel. The upper fragment carries further mechanical sketches of a framed device but no accompanying writing.
On this page
Fixed and moving parts of the shaft mechanism (b c, n m, d e, o p)
b c of the first figure is fixed on its shaft, and likewise n m of the second, so that b c and n m move up and down together with their shaft; d e and o p are the movable parts in both figures. The n m is able to raise the whole pole and open the vessel above and lift b c of the second figure back to its first place.
Buoyancy underwater drives the lifting action
The device is worked by water: n m, being underwater, acts as a light thing and lifts a upward, opening the mechanism above and closing it below. In the contrary motion o p descends through the air as a heavy thing, so the alternation of a weight in air and a float underwater raises the pole.
Heavy in air, light in water: the see-saw of grave and lieve
Descending o p through the air 'acts as a heavy thing,' whereas n m submerged 'acts as a light thing.' Leonardo balances these opposed offices about the shaft so that the buoyant member rises and the heavy member falls, the same principle applied in the contrary motion of the two figures.
Undescribed mechanical sketches on the upper fragment
The upper fragment, catalogued as without writing, shows further mechanical studies: a rectangular frame carrying an upright with a screw or pin, small profile details of the fitting, and a diagonal member. No text accompanies these drawings on the sheet.