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Completion of Conservation Treatment for Jagyeongnu (Clepsydra) of Changgyeonggung Palace, National Treasure No.229 by Cultural Heritage Conservation Science Center
Writer
International Cooperation Division
Date
2020-04-22
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1622

Manufacturing techniques of ‘Susuho’ and real names of four persons out of twelve related to manufacturing were additionally identified.

 

Cultural Heritage Conservation Science Center (CHCSC, Acting Director, Park Jongseo) in National Research Institute of Cultural Heritage under Cultural Heritage Administration, Korea has completed conservation treatment in a year and seven months for Jagyeongnu of Changgyeonggung Palace (National Treasure No.229) which has important significance for research on history of science and technology.

 

Jagyeongnu is the cutting-edge clepsydra which was devised to strike the hour automatically by increasing and decreasing water level as a standard clock in Joseon Dynasty. In 1434 during the reign of King Sejong, the Jagyeongnu has been devised by Jang Yeongsil obeying King Sejong’s order. However, it has not been handed down and in 1536 during the reign of King Jungjong, it has been remade, of which some parts consisting of Pasuho (3 items) and Susuho (2 items) remain until the present at Borugak in Changgyeonggung Palace.

* Pasuho: Three bronze jars in a large, middle and small size to release water

* Susuho: Two long circular bronze containers, equal in size to receive water

 

Since then, when Jagyeongnu was moved and exhibited inside the Gwangmyeongmun in Deoksugung Palace which had been relocated during the period of Japanese colonial rule, conservation treatment such as cleaning soil dust and applying oil has been slightly done for it. However, the conservation condition by adopting those methodologies has not lasted with time to prevent further corrosion and damage to Jagyeongnu made of bronze, and consequently it was transferred to the CHCSC for conservation treatment in June, 2018.

 

CHCSC made a thorough examination of the conservation condition about Jagyeongnu to identify the degree and type of corrosion and came up with proper methodologies of conservation treatment through various experiments. By utilizing the 3D-measurement technique, precise documentation of shapes was done, and it was identified through the non-destructive analysis on conservation condition that corrosion products of bronze had been formed on the surface and oil stain and soil dust stayed on it. Pollutants were removed with the surfactant and ultrasonic scaler and the quality of material was consolidated as well.

* Ultrasonic scaler: Removing pollutants on the surface with an optimum frequency by ultrasonic vibrations

 

With the completion of conservation treatment, the inscription on the upper of Susuho (left) which had not been exactly observed till then was clearly exposed. On the inscription carved (in relief), vertically there were positions and names of twelve persons who had been involved in manufacturing Jagyeongnu at that time. Several letters have been worn away and the identities of four persons out of twelve were not verified in the past but this time there was the achievement that they were newly identified through the conservation treatment by CHCSC.

 

Newly identified names of four figures are Yi Gongjang (李公檣, ?~?), An Hyun (安玹, 1501~1560), Kim Suseong (金遂性, ?~1546), Chae Mujeok (蔡無敵, 1500~1554), and there are old records such as Joseonwangjosillok (Annals of the Joseon Dynasty), Kukjoinmulgo (Biographical dictionary),Mungwabangmok (List of successful applicants who passed the government official examination) showing that they held same positions carved in that inscription at that time of manufacturing Jagyeongnu. Besides, on those historical records the fact that An Hyun, Kim Suseong and Chae Mujeok took considerably important roles in manufacturing Jagyeongnu as professional astronomers has been written.

 

On the surface of Susuho, the dragon patterns flying up into the sky are engraved. To look into the dragon pattern in detail, CHCSC unfolded the surface of Susuho flatways through the 3D scanning and replica.

 

As a result, it is identified that the shape of dragons on the left and right of Susuho are almost identical with a slight difference on their faces and whiskers. In addition, the cloud pattern overlapped on the dragon pattern was observed and it was turned out that the cloud pattern had been placed after the dragon pattern was put first on the surface of Susuho. Based on those facts, it is presumed that Susuho was made by placing sophisticatedly carved patterns in order and there is the high possibility of being cast through wax casting.

 

On the surface of the large-size Pasuho, letters of the date (嘉靖丙申六月 日造) indicating when the Jagyeongnu had been manufactured were carved vertically and the high percentage of silver was detected from the black inscription through the non-destructive component analysis. The inlaid inscription in silver looked black in the past but its original silver-white color was restored through conservation treatment. It seems that the inscription was inlaid with silver on the surface of the large-size Pasuho according to the timing of the completion of Jagyeongnu.

 

The Jagyeongnu of Changgyeonggung Palace for which CHCSC has completed conservation treatment is estimated as a significant scientific cultural heritage demonstrating the pinnacle of technology in Joseon Dynasty. This conservation treatment represents great significance for the success in conserving the original form and restoring missing information of persons in charge and manufacturing techniques. National Research Institute of Cultural Heritage under Cultural Heritage Administration, Korea will make utmost efforts to carry out conservation treatment continuously in the future for various cultural heritages which acquire conservation and restoration.  

 

Senior Researcher Jang, Sungyoon (042-860-9372)

Researcher Lee, Jaesung (042-860-9376)

Cultural Heritage Conservation Science Center

 

 

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