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.
Pocketsize hygrometer. Waterproof hygrometer. Humidity dew point meter. Are used for accurate relative air humidity and temperature measurements. PWT-101 is a pocketsize hygrometer connected with sensor without cable. PWT-102 is connected with the sensor by cable. PWT-103 additionally enables determining of dew point and is equipped with surface temperature probe.