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.
Thermo hygrometers are useful for measurements of humidity. Humidity is a representation of the concentration of water vapour in the air where the value is shown as a percent. Thermo hygrometers have sensors which measure humidity of the air and temperature of the air. Both values will be shown as a digital representation and converted into the desired unit. The result will then be shown via display or on a chart.