psychrometric hygrometer

https://doi.org/10.1351/goldbook.P04939
Instrument by which the @R05267@ of the atmosphere may be determined. It is generally composed of two temperature sensors, one of which measures the temperature of the air; the other sensor is moistened with water and senses the cooling due to @E02227@ of water. The temperature difference between the two sensors is a function of @R05267@; sometimes referred to as a 'wet-and-dry bulb' thermometer.
Source:
PAC, 1990, 62, 2167. (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2196 [Terms] [Paper]