Nicolaus de Cusa,
Leonardo da Vinci
atmospheric sciences
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Hygrometer
- Nicolas de Cusa observed
- If someone should hang a good deal of wool,
- tied together on one end of a large pair of scales,
- and should balance it with stones at the other end
- in a place where the air is temperate,
- it would be found that the weight of the wool
- would increase when the air became more humid,
- and decrease when the air tended to dryness.
- Leonardo da Vinci might have been the first to build one,
- in which the bundle of wool,
- absorbing more water
- when the air was more humid,
- gradually tipped the scale.
Hygrometer designs
- Balancing a clod of dirt with a piece of charcoal.
- Balancing a bundle of wool with a pile of stones.
- Hanging a weight on the string of a lyre.
- Chilling a cone to drip condensed moisture into a beaker.
- Attaching a paper ribbon to a dial on a graduated scale.
- Forcing mercury in an absorbent bag to move a liquid barrier in a tube.
- Calling these “hygrometers” after the Greek word meaning moisture.
- Attaching a hair under tension to a dial.
- Comparing readings from wet-bulb and dry-bulb thermometers.
- Calling these “psychrometer” after the Greek word meaning cold.
- Determining the temperature at which a mirror fogs.
- Drawing air through a silver thimble full of ether until the thimble dulls.
- Ventillating wet-bulb and dry-bulb thermometers with a wind-up fan
- or by swinging them in a circle over your head.
Water witching
- If a teardrop were a potion,
- then consider
- where its magic
- would come from.
- It would come from the stars,
- and from the earth,
- and would be carried
- by every germ of life,
- empowering millions of lives
- swimming in seas,
- raining from clouds,
- and flowing through leaves.
- It shows your pain,
- it shows you care,
- it shows you’re a part
- of life on earth.
Scientists have created many ways to measure humidity. Here is an incomplete chronology assembled from the readings below (not original work):
See also in The book of science:
Readings in wikipedia:
Other readings: