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.
Best Answer: Hygrometer Any instrument for measuring the humidity, or water vapour content, of a gas (usually air). A wet and dry bulb hygrometer consists of two vertical thermometers, with one of the bulbs covered in absorbent cloth dipped into water. As the water evaporates, the bulb cools, producing a temperature difference between the two thermometers.