دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a hygrometer, or psychrometer, attached to a handle and chain cord, which is whirled rapidly through the air. It also has two thermometers. The bulb of one is kept wet so that the cooling that results from evaporation as the thermometers are whirled makes it register a lower temperature than the dry one. The difference between the dry and wet readings is a measure of the relative humidity of the atmosphere. See psychrometer.