The respected Comrade
"A valuable legacy created by our ancestors through their struggle and creative activities, historical sites and relics are an asset of the nation that should be handed down from one generation to the next."
In the 15th century, the field of meteorology made a big step forward in Korea.
It turned into a more modern phase with scientific systems and contents from the one which had been mainly based on intuition and experience.
That was the time when Korean Udometer, a world-first rainfall measuring instrument, was invented.
Before it was invented, the rainfall had been measured only by gauging the depth of rainwater penetrated into the ground.
The Chronicle of Sejong, a written record of series of events happened during the period when the King Sejong of Korean Feudal Dynasty ruled the country, says like this:
"It is a set law that the governors of each province should report the amount of rainfall to the King through relevant offices, but every single piece of lands differs their nature and measuring the depth of rainfall penetrated into the ground is very difficult. So, they come up with an idea that they install an iron cylinder of 2 feet high and 8 inches in diameter on a flat board in Soun Observatory which is then in charge of reporting the depth of rainwater using this instrument. (the Chronicle of Sejong, Volume 93, August, Imo 23(1441))
As it says, the rainfall varied according to the quality of the soil and, even in the same soil, it was not possible to measure the amount of rain accurately.
From the requirement of providing more accuracy in measuring the amount of rainfall, a scientific rainfall-measuring-instrument – a udometer was invented in the 15th century in Korea.
According to the record, this udometer which was invented and used in August, 1441 seemed like a cylinder-shaped iron box of two feet (40cm) high and eight inches (16cm) in diameter and unlike the conventional method of measuring the rainfall, it was installed on a flat board and measured the amount of rainfall from the depth of the rainwater in it.
The udometer was made of iron or copper for the state-level use, and ceramic or earthenware for the local-level use.
Providing the accuracy of measuring the rainfall with a udometer contributed to the comfort of people´s life and developing the agriculture.
This was the first scientific method of measuring the rainfall in the whole world.
In Europe, it was 1639 when Benedetto Castelli in Italy made a udometer and measured the rainfall.
And it was much later that the establishing a udometer system on a nationwide scale to measure the rainfall and using the information for various fields of life was carried out in other countries.
Compared to this, the invention of the udometer in Korea was about 200 years ahead of the others.
The fact that Koreans invented the world´s first rainfall-measuring-instrument, a udometer, vividly shows the outstanding wisdom and talents of Koreans as well as the development level of meteorology in the middle ages of Korea.
