Rain Gauge
an instrument or contrivance for measuring the amount of rain which falls on a given surface.
They are made of various forms. One simple form consists of a copper funnel five to seven inches in diameter, inserted in the neck of a bottle placed on a stand and protected from the sun's rays, to prevent evaporation. The rain collected in the bottle is measured in a glass jar having one-tenth the area of the funnel, and graduated so that a rainfall of onetenth of an inch collected by the funnel is measured by one inch on the side of the vessel. The stand should be placed at a sufficient distance from any buildings, etc., to prevent their affecting the amount falling into the funnel.