Rain Gauge

an instrument used to measure the amount of rainfall at any given place. The Smithsonian rain gauge consists of a tube of brass, ten inches deep and three-fourths of an inch in inside diameter, fitted with a wide funnel-shaped mouth two inches in diameter. The depth of water collected is measured by a scale divided into tenths and hundredths of an inch. The moisture falling within a two-inch circle is collected in a small tube to secure greater accuracy of measurement in case of slight rainfall. A much coarser gauge is serviceable in case of a heavy rain.