De Saussure Hair Hygrometer, 1815-1841

Made:
1815-1841
designer:
Horace Bénédict de Saussure
maker:
William Harris
and
Richard Joshua Harris
Horace B?n?dict de Saussure type hair hygrometer by Richard Joshua Harris, 50 Holborn, London, England, in leather

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Horace B?n?dict de Saussure type hair hygrometer by Richard Joshua Harris, 50 Holborn, London, England, in leather
Science Museum Group
© The Board of Trustees of the Science Museum

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
Materials:
brass (copper, zinc alloy), cord, sharkskin, steel (metal), textile, velvet and wood (unidentified)
Measurements:
overall (in case): 30 mm x 100 mm x 245 mm, .16kg
Identifier:
1983-1300
type:
hygrometer
taxonomy:
  • furnishing and equipment
  • container - receptacle
  • furnishing and equipment
  • measuring device - instrument
credit:
Wellcome Trust