The rain gauge (National Treasure No. 329), which used to be kept at the Chungcheong Provincial Office in Gongju, was made in 1837 (the 3rd year of King Heonjong’s reign). It was taken out of the country by a Japanese meteorologist named Yuji WADA in 1915 during the Japanese occupation of Korea, and was not returned to Korea until 1971, since when it has been kept by the Korea Meteorological Administration (KMA). It is the only extant example of the rain gauges produced and distributed by the central government them to provincial offices across the country during the Joseon period.

The country’s first rain gauge was invented in 1442 (the 24th year of the reign of King Sejong). It is said to be the first device of its kind in the world, invented about 200 years ahead of its Western counterparts. It was an epoch-making device that made it possible to measure rainfall scientifically, replacing previously used instruments designed to measure the amount of water that permeated into the ground.