1950’s Whirling spychrometer Casella London
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A 1950’s Caella London Whirling psychrometer, also known as a sling psychrometer, for measuring humidity, designed by J. J. Griffin & Son Ltd. and made to B.S.2842 by Casella, London, UK, 1950-1953. Contains wet and dry bulb thermometers.
Whirling or sling psychrometers are types of hygrometers for measuring air humidity. They contain two thermometers, one of which has a bulb kept wet with a cloth soaked in distilled water. The device is whirled rapidly in the air, and the difference in the readings between the two thermometers gives a measure of humidity.
Measurements: 22,5 x 17 cm.