Jean-André Deluc
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Jean-André Deluc or de Luc was a geologist, natural philosopher and meteorologist from the Republic of Geneva. He also devised measuring instruments.
Jean André Deluc
Deluc's whalebone hygrometer, on display at the Musée d'histoire des sciences de la ville de Genève.
Introduction page of a 1772 copy of volumes 1 of "Recherches sur les modifications de l'atmosphère"
1772 copy of volumes 1 and 2 of "Recherches sur les modifications de l'atmosphère"
Hygrometer
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A hygrometer is an instrument that measures humidity, that is, how much water vapor is present in the air. Humidity measurement instruments usually rely on measurements of some other quantities, such
Jean-André Deluc
…modifications de l'atmosphère (2 vols. 4to, Geneva, 1772; 2nd ed., 4 vols. Paris, 1784) contain experiments on moisture, evaporation and the indications of hygrometers and thermometers. He applied the barometer to the determination of heights. The Philosophical Transactions published his account of a new hygrometer…
A hair tension dial hygrometer with a nonlinear scale.
The interior of a Stevenson screen showing a motorized psychrometer
Psychrometer probably made in Switzerland circa 1850 by Kappeller (MHS Geneva)