qThe easiest way to measure humidity is through use of a sling psychrometer - A pair of thermometers one of which has a wetted cotton wick attached to the bulb.
qThe two thermometers measure the wet and dry bulb temperature.
qSwinging the psychrometer causes air to circulate about
the bulbs.
qWhen air is unsaturated, evaporation occurs from the wet
bulb which cools the
bulb.
qOnce evaporation occurs, the wet bulb temperature
stabilizes allowing for comparison
with the dry bulb temperature.
qThe wet bulb depression is found with a greater
depression indicative of a dry
atmosphere.
qCharts gauge the amount of atmospheric humidity.
qAspirated and hair hygrometers are alternatives.