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.
psychrometer - a hygrometer consisting of a dry-bulb thermometer and a wet-bulb thermometer; their difference indicates the dryness of the surrounding air. dry-bulb thermometer - an ordinary thermometer with a dry bulb; used to measure the air temperature. hygrometer - measuring instrument for measuring the relative humidity of the atmosphere. wet-bulb thermometer - a thermometer with a bulb that is covered with moist muslin; used in a psychrometer to measure humidity.