Wind-driven gimbal to keep a man upright on a hill
A giant silk vane turning with the wind, its rider held level like a compass
Folio 64r designs a giant 'vane' (ventola) of silk (zendado), cords, canes and poles, 20 braccia or more across, with a perforated ball of green elm hoops at its center mounted like a mariner's-compass gimbal so a man inside always stays upright. Set on a mountain in the wind, the instrument turns with the course of the winds. A second, related device below carries the man with his feet at m and bust at a b on a broad wing fixed atop a dome, with control cords: if the wind lifts h too much he pulls the cord S, and pulling S also lets him settle back to the ground. The circular spoked vane and the mast-and-wing device are both drawn.
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Giant gimballed wind-vane carrying a man
A vane of silk, cords, canes and poles, 20 braccia or more across, holds at its center a perforated ball of green elm hoops fitted like a lodestone compass-box, with a man standing inside. Set on a mountain in the wind, it turns with the course of the winds while the man always keeps his feet.
Wind lifting and control cords
In the related device the man keeps his feet at m and his bust at a b; if the wind coming along line h enters underneath and raises h more than it should, he pulls the cord S downward, and pulling S likewise brings him settling back to the ground.