The longitude (abbreviation: Long., Î», or lambda) of a point on the Earth's surface is the angle east or west from a reference meridian to another meridian that passes through that point. All meridians are halves of great ellipses (often improperly called great circles), which converge at the north and south poles.
Use the dual thermometers to calculate relative humidity. Fisher Scientific Mason's Hygrometer has one dry thermometer and one wet thermometer which provide temperature readings for determining the relative humidity.
Part 1. Buying a Humidity Meter (Hygrometer) 1. The easiest way to measure humidity is to buy a Hygrometer. Hygrometers measure humidity from 0% (dry) to 100% (when any more moisture comes out as precipitation or fog.) Relative Humidity (RH) can change throughout the day. Colder air holds less moisture, so the RH level will normally be higher at night.