De Saussure Hair Hygrometer, 1815-1841
- designer:
- Horace Bénédict de Saussure
- maker:
- William Harris and Richard Joshua Harris
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Horace Bénédict de Saussure type hair hygrometer by Richard Joshua Harris, 50 Holborn, London, England, in leather case, 1815-1841
In 1783, Horace Benedict de Saussure, a Swiss physicist and geologist, made the first hair hygrometer, using a human hair to measure humidity. This type of mechanical hygrometer makes use of the principle that organic substances expand and contract according to changes in relative humidity. The device was calibrated by exposing it to extremes of total saturation and dehydration, thereby establishing the hair's length at 0 and 100 % humidity respectively. Made by Harris.
Details
- Category:
- Meteorology
- Collection:
- Sir Henry Wellcome's Museum Collection
- Object Number:
- 1983-1300
- Materials:
- brass (copper, zinc alloy), steel (metal), cord, wood (unidentified), textile, velvet and sharkskin
- Measurements:
-
overall (in case): 30 mm x 100 mm x 245 mm, .16kg
- type:
- hygrometer and case - container
- credit:
- Wellcome Trust
