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.
Liquid-in-glass thermometers-used to measure the high and low temperature for the day. The design has been in use since the late 1800s. Now replaced by the electronic MMTS system. Hygrothermograph-another way to measure temperature, this instrument provides a continuous trace of temperature on paper.