Geared Winches and a Wax-and-Cotton Hygrometer

Hygrometer of wax and cotton to foretell bad weather

A small balance carries wax on one pan and cotton wool on the other. Because the cotton absorbs moisture from damp air and grows heavier, the beam tips, giving, in Leonardo's words, a way to see when the weather is about to turn bad.

Wheel and pinion tooth count

A note specifies the gearing: 36 teeth and 36 notches to the wheel, engaging a pinion of 6 spindles. The ratio would step the motion of the large geared drums down through the small lantern pinion.

Geared winch and exploded gear train

At the left a large drum bound with a toothed ring is mounted between posts and turned by a crank, with a weight hanging to load it. At the right the same mechanism is drawn taken apart into a row of concentric toothed wheels (several marked A) with a vertical screw-jack, showing how the gears nest together.

A sinistra sopra l'igrometro:

Sotto l'igrometro:

A destra:

A sinistra nel congegno montato, le lettere:

A destra nel congegno scomposto, le lettere:

On the left, above the hygrometer:

Beneath the hygrometer:

On the right:

On the left, on the assembled mechanism, the letters:

On the right, on the dismantled mechanism, the letters:

Geared Winches and a Wax-and-Cotton Hygrometer

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Hygrometer of wax and cotton to foretell bad weather

Wheel and pinion tooth count

Geared winch and exploded gear train