Mechanical studies and a stage set for Pluto's realm
Cranes, screws and wheels; a wear-and-friction problem; and a theatrical scene of the underworld
The sheet is crowded with mechanical drawings — lattice trusses, a tall rigged mast or crane, a threaded screw-shaft, wheels on axles and pulley assemblies — sketched in rapid pen. Two text passages accompany them: a physics question about which part wears away faster, a wheel turning on a fixed axle or the support that carries the moving axle and its wheel, and a set of stage directions for a theatrical spectacle in which a mountain opens to reveal Pluto's residence, with devils, Death, the Furies, Cerberus, weeping children and coloured fires. A short marginal label marks where a performer dresses. Further untranscribed lines of writing also appear on the sheet beyond the three passages given.
On this page
Which wears more: the wheel or the support that carries it
The question is posed whether more wear falls on the wheel turning with its hub on a fixed axle, or on the support that holds the moving axle together with its wheel. Leonardo answers that the support wears more, since it bears both the wheel and the axle, whereas the axle bears only the wheel.
Trusses, hoisting mast, screw and wheels
The upper and left portions of the sheet are filled with rapid mechanical sketches: openwork lattice trusses or beams, a tall mast with diagonal stay and rigging, a threaded screw-shaft set in brackets, and several wheels mounted on axles with pulleys. They are study fragments rather than a single finished device.
A mountain that opens to reveal Pluto's realm
Stage directions describe a mountain lettered a b c d that opens in stages: a b moves into c d, c d into e f, and Pluto is revealed at g, his residence. When this 'paradise of Pluto' opens, devils are to sound twelve pots like infernal voices, and there are to be Death, the Furies, Cerberus, many weeping naked children, and fires of various colours.
'Here one dresses': a note on the stage set
A short label in the left margin, at the centre of the sheet, marks the place of the theatrical set where a performer robes or changes costume. It belongs to the same spectacle as the opening mountain, indicating how the scenery and its service areas were laid out.