Hygrometer
Higrómetro
- Date
- c. 1480 (Leonardo) / 1664 (Hooke) / 1783 (Saussure) · confidence low
- Place
- Milan, Italy / London
- Credited to
- Nicholas of Cusa (concept, 1450), Leonardo da Vinci (wool balance), Robert Hooke (oat beard), Saussure (hair, 1783)
- People
- 👤 Leonardo da Vinci1452–1519👤 Nicolás de Cusa1401–1464
- Field
- Knowledge & symbols
⚠️ Disputed: the sources disagree.
What it is
An instrument that measures air humidity by the change in weight or length of hygroscopic materials (wool, cord, oat beard, hair). It completed instrumental meteorology alongside the thermometer and barometer.
Nicholas of Cusa described the principle (wool on a balance) in 1450; Leonardo drew it; Santorio and Hooke built versions of their own; there is no single inventor.
What it led to
- Instrumental meteorology and observation networks (the Accademia del Cimento, the Royal Society)
- Humidity control in warehouses, print shops and weaving mills
- The study of the water cycle and evaporation
Built on
- Mercury barometer1643
- Precision balance
Made possible
- Saussure's hair hygrometer
- Psychrometer
- Weather stations