Udometer is a precipitation measuring instrument invented in 1441 and used in the Korean feudal dynasty (1392-1910).
Before its invention Korea measured the amount of rainfall by measuring the depth of rain soaked into the ground after raining. But the depth was different according to earthiness. So it was impossible to know the absolute quantity of rain. As a result of various studies on it, a udometer with 2 ja (about 40cm) in height, and 8 chi (about 16cm) in diameter made of iron was invented in August, 1441. It was able to measure the exact precipitation.
A udometer was to measure the quantity of rainfall by putting a round-shaped vessel on a board and getting rainwater in it. Such udometers were installed in the yards of central and local governments; the one of the central government was made of iron and copper and those of local ones were made of porcelain or mud.
Each county observed the time of raining and fine weather and measured the precipitation to report it to their province and each province informed it to the Sounkwan of the central government so that it could control and record it correctly. As a result, udometers were extensively used since 1441 by the central governments and local ones of Korea to observe precipitation. Korea invented the scientific measuring method and introduced the system of synthesizing the results of precipitation for the first time in the world.
In Italy, Benedeto Casteli measured the depth of rainwater with an instrument in 1639 and it was a long time later that udometers were installed on a national scale and the system that the central government controls synthetically the amount of rainfall was established. In this respect, udometer which was invented and used in Korea is 200 years older that in Italy.
Udometer is a world-wide invention to prove the creative talent of the Korean people in the field of meteorology.
