Hair hygrometer after Horace Bénédict de Saussure, late 18th c.

Hair hygrometer after Horace Bénédict de Saussure, late 18th c.

Stock Number: FG_21024


Horace Bénédict de Saussure type hair hygrometer with thermometer, probably German, late 18th century.



Countries of manufacture

Germany, Switzerland

Categories: Scientific, Barometers & Meteorology, Natural history, Surveying Instruments & Mining


In 1783, Horace Benedict de Saussure (1740-1799), a Swiss physicist, and geologist made the first hair hygrometer, using 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. It consists of a wooden frame on which a hair is streched, secured by small jaws, and passing over a pulley with a pointer. A counterweight, connected to the pulley, kept the bundle taut. The hair, which functions as a hygroscopic substance, varies in length with air humidity. The changes can be read on a semicircular silvered scale registering the positions of the pointer. .

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IL Gilgamesh

Gilgamesh was the mythological hero of the cultures of ancient West Asia, who set out on a journey in which he sought youth and eternal life.
Fleaglass Gilgamesh is located in Israel. As an archaeologist researching the material culture of the distant past and using the microscope as a major research tool, for more than two decades I have collected microscopes from the first 300 years of existence of this amazing tool and researched the cultural context of their use. Passion has become an obsession and I cultivate the full and almost unique West Asian collection of historical microscopes. Respectively, I put up for sale surplus or interesting items from the collection. I would be happy to advise any interested collector free of charge. Needless to say, I would love to send photos, information and bibliographic references, and discuss the sale details of the items offered here for sale.

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