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.
Quick Answer. Hygrometers measure the amount of moisture or humidity in the air, but there are a number of different types of hygrometers, and they display their results in different ways. Most hygrometers display their readings in the amount of water in a given volume of air, making the units milliliters per cubic centimeter.