Leonardo's design for measuring the air's humidity resembles a scale. A chunk of was is placed in one tran and an equal weight of cotton in teh other. Because cotton absorbs water but was does not, increased humidity makes the cotton heavier, unbalancing the scale. Changes in the amount of humidity can be read along the calibrated horizontal bar. Leonardo designe the machine to help predict the best flying weather.
Leonardo designed a combination of ropes and pulleys called a block and tackle. The mechanism can be used to lift heavy weights or exert large forces in any direction. Leonardo used ropes and pulleys in a number of his designs, including his clider and theater bird.