The form of hygrometer most commonly met with at meteorological stations is called a psychrometer.
The humidity of the air was observed both by August's psychrometer and Saussure's hygrometer.
The psychrometer is seen inside the shelter on the right in Fig. 2.
Twelve ordinary standard (psychrometer-) thermometers, divided to fifths of a degree (Centigrade).
To overcome this difficulty another form of psychrometer has been devised.
psychrometer psy·chrom·e·ter (sī-krŏm'ĭ-tər)
An instrument that uses the difference in readings between thermometers specialized to measure the moisture content or relative humidity of air.
See under hygrometer.