Advanced
A Study on the Operation Mechanism of Ongnu, the Astronomical Clock in <italic>Sejong</italic> Era
A Study on the Operation Mechanism of Ongnu, the Astronomical Clock in Sejong Era
Journal of Astronomy and Space Sciences. 2011. Mar, 28(1): 79-91
Copyright ©2011, The Korean Space Science Society
This is an Open Access article distributed under the terms of theCreative Commons Attribution Non-Commercial License(http://creativecommons.org/licenses/by-nc/3.0/)which permits unrestrictednon-commercial use, distribution, and reproduction in any medium,provided the original work is properly cited.
  • Received : July 07, 2010
  • Accepted : November 11, 2010
  • Published : March 15, 2011
Download
PDF
e-PUB
PubReader
PPT
Export by style
Share
Article
Author
Metrics
Cited by
TagCloud
About the Authors
Sang Hyuk Kim
Korea Astronomy and Space Science Institute, Daejeon 305-348, Korea
astro91@kasi.re.kr
Yong Sam Lee
Chungbuk National University Observatory, Cheongju 361-763, Korea
Min Soo Lee
Chungbuk National University Observatory, Cheongju 361-763, Korea
Abstract
Ongnu (Jade Clepsydra; also called Heumgyeonggaknu) is a water clock was made by Jang Yeong-sil in 1438. It is not only an automatic water clock that makes the sound at every hour on the hour by striking bell, drum and gong, but also an astronomical clock that shows the sun's movement over time. Ongnu‘s power mechanism used is a water-hammering method applied to automatic time-signal device. The appearance of Ongnu is modeled by Gasan (pasted-paper imitation mountain) and Binpungdo (landscape of farming work scene) is drawn at the foot of the mountain. The structure of Ongnu is divided into the top of the mountain, the foot of the mountain and the flatland. There located are sunmovement device, Ongnyeo (jade female immortal; I) and Four gods (shaped of animal-like immortals) at the top of the mountain, Sasin (jack hour) and Musa (warrior) at the foot of the mountain, and Twelve gods, Ongnyeo (II) and Gwanin on the flatland. In this study, we clearly and systematically understood the time-announcing mechanism of each puppet.Also, we showed the working mechanism of the sun-movement device. Finally, we completely established the 3D model of Ongnu based on this study.
Keywords
1. INTRODUCTION
For the kings of Joseon dynasty, astronomical observation was very important in politics. Understanding of the precise movement of celestial bodies was enabled by using various astronomical instruments including large and small size Ganui (simplified armillary sphere), Honui (armillary sphere), Honsang (celestial globe), Angbuilgu (hemispherical sundial), Ilseongjeongsiui (sun-and-star time determining instrument), Gyupyo (gnomon), Jagyeongnu (striking clepsydra) and so on. However, most of the astronomical instruments were installed in the back garden of the palace and thus it was inconvenient for the king to check the time instantly. 1 Thus, Heumgyeonggak was built at the west side of Cheonchujeon (the office of the king) and Ongnu (jade clepsydra; also called Heumgyeonggaknu )after the name of the building in which it was installed) was installed in it so that the king could check the time immediately. 2
Ongnu was made by Jang Yeong-sil who was also made various kinds of astronomical instruments such as Ganui in 1438 following the order of King Sejong (1418~1450). Kim Don (1385~1440) wrote the record about the completion of Heumgyeonggak. According to Sejong sillok (history book during Sejong era) Heumgyeonggak was built by the strange scale and design which were prepared by King Sejong . 3 This indicates that King Sejong himself might have been deeply involved in the fabrication of Ongnu from the beginning.
Previous studies about Ongnu including Jeon (1963, 1994, 1998), Needham et al. (1986), Hahn & Nam (1997) and Nam (2002) were interpreted the relevant literature and introduced the applied technology. Recently, Kim (2007) and Lee et al. (2009) worked on the design of the floor arrangement. In addition, Kim (2009) and Kim et al. (2010) analyzed the mechanical puppet instrument in Ongnu and stated that it might have affected the puppet instrument of Yesandae (moving Sandae. comprehensive moving stage for puppet play direction) used in 18th century. According to Hong (1998), Sandae may be the stage setting reflecting Korean culture and history of the long period from the Three Kingdom Period to Goryeo and Joseon Eras. Hence, understanding the moving puppet of Ongnu as one of the development procedure of the puppet that used to be installed on Sandae means that the tradition of Gasan and the puppet instrument might have affected the time-signaling puppet of Ongnu.
On the other hand, the operation mechanism of Ongnu was independently introduced in ‘ History of Technology Development in Joseon ’ in North Korea (History of Technology Development in Joseon Compilation Committee 1997). The studies conducted in North Korea mainly reflect the analysis of the power transmission mechanism by Needham et al. (1986). However, the design and the conceptual illustration of the inner operation instrument were firstly introduced, which helped overall understanding of Ongnu. In this study, we analyzed the outward structure and detailed operation structure of Ongnu based on the records in Sejong sillok which introduces the operation structure in details. Additionally, we completed the schematic diagrams of each part and the overall 3-dimensional reconstruction image and thus understood the operation mechanism organically.
1Sejong sillok, 80:5a:line 11.
2Sejong sillok, 80:5a:line 11~12.3Sejong sillok, 80:5a:line 6.
3Sejong sillok, 80:5a:line 6.
2. OUTWARD STRUCTURE AND OPREATION CONTENTS OF ONGNU
The outward structure and operation structure of Ongnu were described in Sejong sillok . 4 The records shows the specifications and detailed operation mechanisms including the operating principle of Ongnu, the operation of the sun movement device, the Ongnyeos (I) (jade female immortals) and Four gods (Shaped of animal-like immortals) at the top of the mountain, the operation of Sibodae (time signal platform) and the time-signaling puppet, the operation of Ongnyeos (II) and Twelve gods (shaped of animal-like immortals) on the flatland and the operation of Nusudae (supply of water platform) ( Table 1 ). This chapter introduce the records from the literature about Ongnu and the translation by Jeon (1998) as well as the related technological aspects (2.1~2.7). 5
- 2.1 Dimension and Operating Principle of Ongnu
The original record about the dimension and operating principle of Ongnu is as follows:
  • A paseted-paper “mountain” about 7Cheokhigh is set up within theHumgyeonggakwith the timekeeping wheel of theOngnu,which is set to rotate by means of falling water.
Ongnu was installed at the center inside Heumgyeonggak. The outward appearance of Ongnu can be distinguished into Gasan (M), the horizontal plane (H) and the base (B) ( Fig. 1 ). Mechanism wheels were installed inside Gasan and these wheels was by water-hammering method. The water-hammering method used for this might have affected the operating method of the
Records in Sejong sillok (80:5a~6a).
Lager Image
Records in Sejong sillok (80:5a~6a).
Lager Image
Keys map Ongnu. M: Gasan (imitation mountain) H: horizontal B: base.
water-operation method armillary clocks fabricated in 1657 and 1669 (Kim 2007). Hahn & Nam (1997) assumed that a sino-arabic inkling vessel was used for the water-hammering instrument applied to Ongnu and thus the water-hammering instruments in the later times might have adopted a similar method.
The record analysis implies that Ongnu (water clock) and the mechanism wheels were inside the mountain, but what was referred to as Ongnu included the water clock, the mechanism wheel device and the base in the mountain and the description reflected that concept.
Gasan was composed of pasted (starched) paper and the height was 7 cheok. Generally, Chucheok scale is used for the fabrication dimensions of the astronomical instruments and measurement equipments. However, the height of Gasan presented here was not related to measurement equipments, the scale, cheok, was considered as the Yeongjocheok which was used for the construction of buildings. Hence, applying the Yeongjocheok value of 1 cheok which was 30.7 cm, the calculation results in 214.9 cm of the height. Assuming the height of the base and the horizontal plane to be 3 cheok (92.1 cm), the overall height becomes 317 cm. Various gear instruments composed of the water clock, mechanism wheels and the water wheel with the overflow function were to be operated inside Ongnu.
- 2.2 Sun Movement Device
The original record about the sun movement device in Sejong sillok is as follows:
  • A golden image of the sun, made out of a cannonball, is provided to move across the middle of the mountain surrounded by multicolored cloud. The sun makes its daily revolution, appearing at the rim of the mountain at dawn and hiding behind it at dusk. The inclination of the sun varies depending upon the polar distance while its rise and set follow that of the true sun for each of the fortnightly periods concerned.
The record stated that there was a golden image of the sun which was the size of a cannonball. 6 The sun device represented the time in a day. In Honsang which was produced in a similar era, an ecliptic ring was installed and the sun device was hung on the ecliptic ring. The movement of the sun in a year was represented by pulling the thread and the sun device was designed to be moved backward about 1 degree per day on the ecliptic. Considering such as situation at that time, it can be assumed that an ecliptic ring was installed in Gasan of Ongnu and the movement of the sun in a day was represented along the ecliptic ring. 7
The record, “The inclination of the sun varies depending upon the polar distance while its rise and set follow that of the true sun for each of the fortnightly periods concerned,” allows to assume the existence of an ecliptic ring in Ongnu. The movement of the ecliptic ring and the sun device indicated the variation of the sunrise and sunset directions and the meridian altitude depending on the seasons. Hence, although Ongnu was a water clock, it played the role of an astronomical clock representing the actual movement of the sun.
- 2.3 Operation of Ongnyeo (I) and Four Gods at the Top of the Mountain
The original record about the Ongnyeos (I) and Four gods at the top of the mountain in Sejong sillok is as follows:
  • Below the imitation sun stand, four female immortals placed at the four cardinal points, each with a golden bell in hand. At the beginning of each of the three morning double hours ranging fromIntoJin,the immortal in the east jingles the bell, followed by the next immortal to the west for the next three double hours, and similarly by those to the north and the south by turns. At the four cardinal points on the ground stand the Four gods, each facing the central mountain. The first of the Four gods, the Blue Dragon, faces north at the double four ofIn,south atMyo,and again west atSa.Next, the Red Bird faces east, and so on.
There were Four Ongnyeos (I) and Four gods at the top of the mountain. The four Ongnyeos (I) were located above the Four gods and they signaled the time by shaking the golden bell. Fig. 2 shows the working mechanism of Ongnyeo (I) and Cheongryong. Cheongryong (Blue Dragon or Blue-Green Dragon)8 and Ongnyeo (I) faced each other. Cheongryong made a right turn by 90 degrees at every 1 Sijin (double hours in modern time) and it turned back to the original position to face Ongnyeo (I) after passing the angles corresponding to the times, In (tiger, 03~05), Myo (hare, 05~07) and Jin (dragon, 07~09). 9 In other words, the Ongnyeo (I) located at the east side was to take charge of the time corresponding to 3 Sijin out of the whole 12 Sijin (twelve double hours).
At the moment when the time is changed, Ongnyeo (I) signaled the time by shaking the golden bell at her hand. The signals were given at every Cho (beginnings double hours) and Jeong (mid-points double hours), which
Lager Image
Working mechanism of Ongnyeo (I) and Cheongryong.
Working mechanism of Ongnyeo (I) and Four gods.* (hour). Ja-Cho (23), Ja-Jeong (24), Chuk-Cho (1), Chuk-Jeong (2), In-Cho (3), In-Jeong (4), Myo-Cho (5), Myo-Jeong (6), Jin-Cho (7), Jin-Jeong (8), Sa-Cho (9), Sa-Jeong (10), O-Cho (11), O-Jeong (12), Mi-Cho (13), Mi-Jeong (14), Sin-Cho (15), Sin-Jeong (16), You-Cho (17), You-Jeong (18), Sul-Cho (19), Sul-Jeong (20), Hae-Cho (21), Hae-Jeong (22).
Lager Image
Working mechanism of Ongnyeo (I) and Four gods. * (hour). Ja-Cho (23), Ja-Jeong (24), Chuk-Cho (1), Chuk-Jeong (2), In-Cho (3), In-Jeong (4), Myo-Cho (5), Myo-Jeong (6), Jin-Cho (7), Jin-Jeong (8), Sa-Cho (9), Sa-Jeong (10), O-Cho (11), O-Jeong (12), Mi-Cho (13), Mi-Jeong (14), Sin-Cho (15), Sin-Jeong (16), You-Cho (17), You-Jeong (18), Sul-Cho (19), Sul-Jeong (20), Hae-Cho (21), Hae-Jeong (22).
means that the hammering signals were generated in the interval of one modern hour. The operation of the Ongnyeo (I) at the south, west and north as well as Jujak (Red Bird or Vermillion Bird) 10 , Baekho (White Tiger) 11 and Hyeonmu (Black Tortoise or Dark Warrior)12 was the same with the operation of Cheongryong ( Table 2 ).
- 2.4 Time Signal Platform and Operation of Time Signal Puppets: Sasin and Musas
The original record about the time signal platform and the operation of the time signal puppets in Sejong sillok is as follows:
  • At the southern foot of this mountain stands a high platform where an “hour jack”(Sasin)stands turning his back to the mountain, while three warriors, all in armor, are arranged in such a way that the first one, carrying an iron hammer, stands in the east facing west; the second one, carrying a drumstick, stands near the west facing east; and the third one, carry a gong stick, also stands in the west facing east. At each double hour, the hour jack turns to face the bell man and they strike their respective instruments at each night watch.
The Sibodae (time signal platform) was located at the south part of the foot of the mountain. Sasin (hour jack) and three Musas (warriors) were on Sibodae. Jongin (striking bell puppet, Ⓑ) at the right side of Sasin, Goin (striking drum puppet, Ⓓ) and Jeongin (striking gong puppet, Ⓖ) at the left. They rang the bell at every hour and stroke the drum and gong at every Gyeong-Jeom Time. Sasin was directed to look at Jongin when the bell rang and Goin and Jeongin when the drum and gong rang ( Fig.3 ). In other words, the setting included the theatrical element that the Musa notified the time responding to the signal received from Sasin.
Such a theatrical context can be also found in the actions of the Gangtaegon (angler), the Seonnye (Taoist fairy) and the young body that appear in Yesandae (Kim 2009). The stage of Gasan in Yesandae also appears in Ongnu in the same manner. Gangtaegon played the role of controlling the motion of the Seonnye and the young body, which is also found in the relationship between Sasinand Musa in Ongnu. Hence, the common characters such as Gangtaegon and Sasin, and the Seonnye and Ongnyeo as well as the common space settings can be considered as the theatrical direction based on the common motif of Ongnu and Yesandae .
Sejong sillok indicates that the time signal system of Ongnu was basically similar to that of Jagyeongnu (striking clepsydra). The signal at every double-hour was made by striking the bell in Jagyeongnu. For Gyeong-Jeom Time, the drum and gong were stricken at every Gyeong (divied night into five equal parts) and Jeom (divied Gyeong into five equal parts) (Table 3). Different from the striking of Jagyeongnu system, the drum and gong were stricken for 5 times repeatedly from 1- Gyeong and 3- Jeom to 5- Gyeong and 3-Jeom in Dangjongbeop (rule of striking bell) that was established in the first year of King
Lager Image
Working mechanism of Sasin Jongin Goin and Jeongin.
Lager Image
Working mechanism of Ongnyeo (II) and Twelve gods.
Yejong (1468~1469) (1469) (Nam 1995). It is assumed that the time-signaling method of Ongnu in the time of King Sejong might have followed the striking method of Jagyeongnu.
- 2.5 Operation of Ongnyeo (II) and Twelve Gods on the Flatland
The original record about Ongnyeo (II) and Twelve gods in Sejong sillok is as follows:
  • On the level ground are Twelve gods occupying their respective positions and behind them are holes. At the hour ofJa,the hole behind the Rat open while an immortal with a time tablet(Sipae)comes out and the Rat stands still. The work is done by the Ox at the double hour ofChukwith a similar performance, and so on down the successive double hours.
The visualization of the time in Ongnu was demonstrated by the operation mechanism of Ongnyeos (II) and Twelve gods ( Fig.4 ). Having Gasan at the center, Twelve gods were prostrating at the twelve directions of the flatland. Ongnyeo (II) came up with the Sipae (time dial) for the time, and then one animal god corresponding to the time among the Twelve gods stood up. Ongnyeo (II) was to come out, opening the hole at the rear side of the Twelve gods. One Sijin later, the next Ongnyeo (II) hid herself beneath the hole, and the corresponding one among the
Time signal of Gyeong-Jeom.
Lager Image
Time signal of Gyeong-Jeom.
Twelve gods prostrated once again. Later at the next hour, Ongnyeo (II) corresponding to the time came up with the Sipae for the time and the corresponding animal god performed the action repeatedly.
Considering that Ongnyeo (II) came up with the individual Sipae on which the letter corresponding to the Twelve gods was written, 12 Ongnyeo (II) were waiting inside and came out through the hole. It is also assumed from the actions of the Twelve gods such as prostrating and standing that the structure was designed so that the animal gods could be directed to wear cloth. In addition, the structure in which Ongnyeo (II) came out through a hole may indicate the interlocked structure between the appearance of Ongnyeo (II) and the opening-closing of the hole. The Twelve gods were arranged clockwise when viewed from the top of Gasan.
- 2.6 Water Supply Platform: Nusudae and Escapement
The original record about Nusudae and escapement in Sejong sillok is as follows:
  • At the south point is located another platform carrying an “advisory vessel”, which lies on its side when empty, stands upright if half-full with water, and falls over again if filled to the brim. All these are performed completely automatically without any help from anyone.
Nusudae (water supply platform) was located at the right south and controlled by Gwanin. Nusudae was the core device that made the time accurate in Ongnu.
Lager Image
Working mechanism of Gwanin and Nusudae. A: Uigi B: Nusuho C: tube D: Soho E: string (Cheonhyeong device connection line).
Gwanin supplied a certain amount of water through a golden bottle in Nusudae, which follows the water-hammering method in which the water wheel was to be moved by a certain amount of water ( Fig. 5 ). 13 As already shown in the Chinese Shui yün i hsiang t'ai system structure, the rotation of the water wheel could be controlled by supplying a certain amount of water hanging a weight. Such an escapement technology by which the wheel movement speed was precisely controlled was the key technology of water-hammering method water clock.
- 2.7 Landscape of Four Seasons: Binpungdo
The original record about Binpungdo in Sejong sillok is as follows:
  • Around the mountain is an enclosure with painting of rural scenery in the four seasons, and wood carvings of men, birds, and plants displaying the labors undertaken by the people in the different seasons.
The decorations of Ongnu, Gasan were the figuration of the drawings of Sigyeong Binpungdo (landscape of hard farming work scene). Binpungdo illustrated the life of common people based on Sigyeong which is a Confucianism scripture. Binpungchilwoldo were the drawings that expressed the contents of Sigyeong Binpungchilwolpyeon that were the poems in the form of Wolryeong (monthly table of the regular annual events of farm family or the country, separately recorded for each month) where the life of agriculture and sericulture, the lifeworks of the people in Chou era of Chinese history, and the relevant customs were recited. In 1424, King Sejong ordered to draw the pictures expressing the hard and difficult life of the people of the country in the form of Wolryeong, imitating Binpungchilwoldo and Muildo (the pictures based on the contents of Seogyeong Muilpyeon) of China (Jeong 2000).
Hence, the picture that was drawn on Gasan was Binpungchilwoldo that was newly produced in Joseon ( Fig. 6 ). 14 Binpungchilwolpyeon on Gasan expressed the landscape of spring at the east, summer at the south, autumn at the west, and winter at the north. Wood carvings of man, bird, animal, grass and tree were additionally installed on it. The theatrical direction was added to make harmony among Four gods, Twelve gods, Gwanin,
Lager Image
Binpungchilwoldo in Joseon.
Sasin, Musas, and Ongnyeos (I, II) so that they could be expressed as a three-dimensional shape in Ongnu Gasan.
4Sejong sillok, 80:5a:line 5~6a:line 8.
5In the Jeon (1998)’s translation, proper noun is changed Romanization, and white Italic.
6Joseon 17~18 centuries, Lead or Inon Ball, size: 9~60 mm (Pictorial Sketches of Collections ROK ARMY MUSEUM, 1990. 12., Korea Military Academy, p. 33)
7Needham et al. (1986)’s presume: “The motion of the sun could have been taken directly from an axle driven by the clepsydrally released balls” 8Lexical meaning is a blue dragon but it explaining, in accordance with Oriental civilization, a imaginary apotheosized animal which is combined with several animal's specific parts such as hands of tiger, neck of snake and so on. It occasionally called as "Blue Dragon" or "Blue-Green Dragon."
8Lexical meaning is a blue dragon but it explaining, in accordance with Oriental civilization, a imaginary apotheosized animal which is combined with several animal's specific parts such as hands of tiger, neck of snake and so on. It occasionally called as "Blue Dragon" or "Blue-Green Dragon."
9Ja (rat, 23~01), Chuk (ox, 01~03), In (tiger, 03~05), Myo (hare 05~07), Jin (dragon, 07~9), Sa (snake, 09~11), O (horse, 11~13), Mi (sheep, 13~15), Sin (monkey, 15~17), You (cock, 17~19) Sul (dog, 19~21), Hae (boar, 21~23).
10Lexical meaning is identified as oriental phoenix but it imaged as a imaginary apotheosize red cock in the cultural history of Korea. It occasionally called as "Red Bird" or "Vermillion Bird." 11Lexical meaning is a white tiger but it explaining, in accordance with Oriental civilization, a imaginary apotheosized animal which is combined with tiger and dragon. It occasionally called as just "White Tiger." 12 Lexical meaning is a black tortoise but it explaining, in accordance with Oriental civilization, a imaginary apotheosized animal which is imaged that heads of tortoise and snake hung on both sides of tortoise shaped body each. It occasionally called as "Black Tortoise" or "Dark Warrior."
11Lexical meaning is a white tiger but it explaining, in accordance with Oriental civilization, a imaginary apotheosized animal which is combined with tiger and dragon. It occasionally called as just "White Tiger."
12 Lexical meaning is a black tortoise but it explaining, in accordance with Oriental civilization, a imaginary apotheosized animal which is imaged that heads of tortoise and snake hung on both sides of tortoise shaped body each. It occasionally called as "Black Tortoise" or "Dark Warrior."
13The figure of Nusudae is the schematic diagram to express the operation. Through the follow-up study, Nusudae and the specific mechanism of the inner device will be investigated. 14Lee, Bang Un (1761~?)’s Binpungchilwoldo (Rice in Korean History, New Millennium Special Exhibition, 2000. 7., The National Museum of Korea, pp. 128-129).
14Lee, Bang Un (1761~?)’s Binpungchilwoldo (Rice in Korean History, New Millennium Special Exhibition, 2000. 7., The National Museum of Korea, pp. 128-129).
3. THREE-DIMENSIONAL MODELING
The key characteristics of the time signal puppets of Ongnu are shown in Table 4 . Ongnu was divided into the top of the mountain, the foot of the mountain and the flatland and the puppet name, puppet number, main characteristics and the position were marked. Among the time signal puppets, Four gods and Twelve gods have the shapes of animals, and other puppets are in the form of persons wearing the corresponding official clothes or costumes. The 3D modeling of the time signal puppets was carried out based on these constitutional contents. 15
Among the time signal puppets, Four gods and Twelve gods are shown as gods in the form of typical animals. Such forms are also found in the stone objects located around the stone steps in the Geunjeongjeon Hall of Gyeongbok Palace (Cultural Heritage Administration 2000). The costumes of Sasin, Musas ( Jongin, Goin, Jeongin ), and Gwanin followed the fashion style of the early Joseon Dynasty. The figures of Ongnyeo (I, II) were designed based on the Seonnye found in traditional drawings. Fig. 7 shows the main time signal puppets.
The main structure of Ongnu is shown in Table 5 . Gasan was divided into detailed instruments including the imitation mountain (Gasan), the sun movement device, and the base. The contents of the theatrical direction and motion of each structure were expressed to help the 3D modeling of the entire Gasan.
Sibodae and Nusudae of Ongnu had the functions of overseeing and notifying the time and maintaining the time to be accurate. Thus, the overall constitution of Sibodae was designed to be in the form of Eojwa (king´s chair) of Gyeongbok Palace upon the embankment. Since Eojwa was the core space for a king to care for the state affairs or to carry out the national policy, the design can be well corresponding to the observation of the time from the sky and the notification performed on Sibodae and Nusudae.
The sun movement device consisted of the ecliptic ring and the sun device. The ecliptic ring was established as a traditional armillary sphere part and as a movement device to which the armillary sphere mechanism was added to the top. The overall mapping of the flatland was carried out referring to the pictures such as Binpungchilwoldo. The round shape of the ecliptic ring on Gasan was extended to the round shape of the mountain and the base supporting the flatland was designed in a square shape considering the view to the universe at that time which was ‘the sky is a circle and the earth is a square.’ The overall outer appearance of Ongnu is shown in Figs. 8 and 9 .
153D Design by Park, Jae-Hyeon.
4. OPERATION MECHANISM ANALYSIS
The water wheel of Ongnu was operated by the water-hammering method. The motion of the time signal puppets and the operation of the sun device were empowered by the dynamic power of the water wheel. Needham et al. (1986) assumed that the power technology applied
Characteristics of time signal puppets.
Lager Image
Characteristics of time signal puppets.
Characteristics of device.
Lager Image
Characteristics of device.
to Ongnu was by the buoyancy of the supplied water. In other words, they assumed that the force generated when the buoy floated served as the rotational force. Such a method was the characteristic constitution of the water clock designed by Al-Jajari of the Islamic world in 13th century (Hill 1989). However, careful analysis of the records found in Sejong Sillok makes it probable that the dynamic power is by the water wheel rotating at a constant speed like in Chinese Shui yün i hsiang t’ai that was developed earlier. Hence, the power transmission system inside Ongnu was constituted as shown in Fig. 10 .
Producing a constant dynamic power based on the water-hammering method was realized by the working mechanism of Nusudae that had the escapement system.
Lager Image
Time signal puppets.
Water was supplied from the water clock in Nusudae. A weight was hung at the handle of the bowl so that a constant amount of water could be contained in the bowl in Nusudae. Thus, the mass of the water contained in the bowl was the same with the weight hung at the handle and the dynamic power generated here was transmitted to the water wheel.
Lager Image
Sibodae (left) and Nusudae (right).
Lager Image
Three-dimensional modeling cut of Ongnu.
Lager Image
Keys map of Ongnu’s inside and power supply mechanism of Ongnu. WC: water clock WW: water wheel E: escapement W1: wheel 1 (base) W2: wheel 2 (time signal platform) W3: wheel 3 (top of a mountain).
Lager Image
Working mechanism flow chart of Ongnu.
The power transmitted to the water wheel operated the mechanism wheel of Ongnu. There were rotational disks from the first level to the third level in the mechanism wheel. The rotation wheel at the first level (W1) transmitted the power to the Twelve Ongnyeos (II) and Twelve gods on the flatland. The rotation wheel at the second level (W2) transmitted the power to the time signal puppets device. The rotation wheel at the third level (W3) transmitted the power to Four Ongnyeos (I) and Four gods. The top level transmitted the power to the sun movement device. In the follow-up studies, the specific operation mechanisms of the inner structures of Ongnu will be analyzed in details through the analysis of the mechanisms of Shui yün i hsiang t’ai.
Fig. 11 is the flow chart that describes the overall operation and working information of Ongnu in a manner that is easy to understand. The specific operations are introduced for each floor of Gasan. At the first floor, the visual information was provided to notify the time with Twelve gods. At the second floor, the motion of the time signal puppets device and the visual information and the auditory information by hammering of the bell, drum, and gong were simultaneously realized. At the third floor, the visual and auditory time information was provided by the bell sound of Ongnyeos (I) and the motion of Four gods. At the top floor, the theatrical direction was realized to visualize the daily movement of the sun and the annual movement of the sun on the ecliptic plane.
5. CONCLUSIONS
Ongnu was an automatic water clock installed in Heumgyeonggak. The name “Heumgyeong” which means ‘respect’ was from the sentence in Yojeon Section of Seogyeong, ‘Respect as to heaven and let the people know the time and seasons.’ 16 Binpungdo for the four seasons were drawn at the four directions of the Gasan of Ongnu. King Sejong watched the difficult situations of the farmers through the pictures of Binpungdo and practiced the meaning of Heumgyeong by means of Ongnu.
We understood the overall outer structure and the principle of the inner power structure of Ongnu based on the literature record found in Sejong sillok . Ongnu was a novel type automatic water clock completed by Jang Yeong-sil 4 years after he fabricated and operated Jagyeongnu. There was a basic water clock using a constant flow of water in Heumgyeonggak and the visual and auditory time information was notified through the time signal puppets. In addition, the astronomical clock was operated to express the time in a day and the annual motion of the sun through the operation of the sun move-
ment device. The escapement system that generated power by operating the water wheel through the constant water flow indicated that the water supply and the water hammering method of Chinese Shui yün i hsiang t’ai was similarly applied.
Jagyeongnu, operated in 1434, consisted of three puppets hammering the bell, drum, and gong. On the contrary, in Ongnu, a total of 37 puppets (including the animal-like gods) were demonstrated in a large scale including Ongnyeos (I) and Four gods at the top of the mountain, Sasin and Musas (Jongin, Goin, Jeongin) at the foot of the mountain, and Ongnyeos (II), Twelve gods and Gwanin on the flatland. The motion of these puppets was similar to the puppet play in Yesandae in Joseon Era. This indicates that the theatrical element of Sandae developed since the Three Kingdom Period was applied to Ongnu Gasan.
Three-dimensional modeling was performed with respect to the structure of Ongnu and the outer appearance recovery model was completed. The detailed appearance of the individual time signal puppets, Sibodae, Japsangs and Binpungdo of Gasan was expressed. The costumes and the design of the puppets were realized in the fashion of Joseon Era. These modeling works were reflected to the basic design Ongnu. In addition, through the analysis and realization of the structure, and the optimized 3D model was completed. As regards the inner structure of Ongnu, the role and structure of the water clock, Nusudae, water wheel and the gear constitution for each floor were presented. This work allowed the provision of the fundamental data for the detailed design of the inner structure of Ongnu. Further study on the operation mechanism of the inner instruments is required for the restoration of the Ongnu prototype.
- INDEX
Angbuilgu 仰釜日晷, hemispherical sundial
Baekho 白虎, White Tiger
Binpungchilwoldo ?風七月圖
Binpungchilwolpyeon ?風七月篇
Binpungdo ?風圖, landscape of hard farming work scene
Cheok 尺, scale unit
Cheonchujeon 千秋殿, the office of the king
Cheongryong 靑龍, Blue Dragon or Blue-Green Dragon
Cheonhyeong 天衡, oriental escapement device
Cho 初, beginnings double hours
Chou
Chucheok 周尺; 1尺 = 20.7 cm
Daehogun 大護軍, the name of a high public office
Dangjongbeop 撞鐘法, rule of striking bell
Eojwa 御座, king´s chair
Ganui 簡儀, simplified armillary sphere
Gasan 假山, pasted-paper imitation mountain
Goin 鼓人, striking drum puppet
Gwanin 官人
Gyeong-Jeom Time 更點時間; Gyeong 更, divied night into five equal parts; Jeom 點, divied Gyeong into five equal parts
Gyupyo 圭表, gnomon
Heumgyeong 欽敬
Heumgyeonggak 欽敬閣
Honsang 渾象, celestial globe
Honui 渾儀, armillary sphere; also called Honcheonui渾天儀
Hyeonmu 玄武, Black Tortoise or Dark Warrior
Ilseongjeongsiui 日星定時儀, sun-and-star time determining instrument
Jagyeongnu 自擊漏, striking clepsydra
Jang Yeong-sil 蔣英實
Jeong 正, mid-points double hours
Jeongin 鉦人, striking gong puppet
Jongin 鐘人, striking bell puppet
Jujak 朱雀, Red Bird or Vermillion Bird
Kim Don 金墩(1385~1440)
Muildo 無逸圖, the pictures based on the contents of Seogyeong 書經 Muilpyeon 無逸篇
Musas 武士, warriors
Nusudae 漏水臺, supply of water platform
Nusudae 漏水臺, water supply platform
Ongng 玉漏, Jade Clepsydra; also called Heumgyeonggaknu 欽敬閣漏
Ongnyeos 玉女, jade female immortals
Sandae 山臺
Sasin 司辰, jack hour
Sejong 世宗, King SeJong (1418~1450) of Joseon
Seogyeong 書經
Shui yün i hsiang t’ai 水運儀象臺
Sibodae 時報臺, time signal platform
Sigyeong 詩經
Sijin 時辰, 1 Sijin = double hours in modern time; Ja (子, rat, 23~01), Chuk (丑, ox, 01~03), In (寅, tiger, 03~05), Myo (卯, hare 05~07), Jin (辰, dragon, 07~9), Sa (巳, snake, 09~11), O (午, horse, 11~13), Mi (未, sheep, 13~15), Sin (申, monkey, 15~17), You (酉, cock, 17~19) Sul (戌, dog, 19~21), Hae (亥, boar, 21~23)
Sipae 時牌, time dial
Soho 小壺, small water bottle
Uigi 倚器, slanted bowl
Wolryeong 月令, monthly table of the regular annual events of farm family or the country, separately recorded for each month
Yejong 睿宗, King Yejong (1468~1469) of Joseon
Yeongjocheok 營造尺; 1尺= 30.7 cm
Yesandae 曳山臺, moving Sandae. comprehensive moving stage for puppet play direction
Yojeon 堯典
16Sejong sillok, 80:5b:line 13~14.
Acknowledgements
This work was supported by the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2009-351-2-C00120).
References
Cultural Heritage Administration 2000 Geunjeongjeon survey investigation report vol. 1 (Singihoek Press Seoul 332 - 361
Hahn YH , Nam MH 1997 Reconstruction of the armillary sphere of mid-Chos?n: the armillary clocks of Yi Minch’ ?l J Korean Hist Sci Soc 19 3 - 19
Hill DR 1989 The book of knowledge of ingenious mechanical devices Hijra Council Pakistan (ed. &amp;amp;amp;amp;amp; transl.) Original author: Al-Jazari
1997 History of Technology Development inJoseonCompilation Committee History of technology development inJoseon:4 Science Encyclopedia Synthesize Publishing Company Pyeongyang 292 - 293
Hong MR 1998 A study of the meaning of San Dae and its construction Dongguk University
Jeon SW 1963 Study on the clock manufacture during the Yi Dynasty Hyangto Seoul 17 49 - 114
Jeon SW 1994 Time clock and history Wolgansigyesa Seoul 77 - 82
Jeon SW 1998 A history of science in Korea Jimoondang Publishing Company Seoul 88 - 89
Jeong BM 2000 A study of Korean genre paintings Hangil Art Publishing Co Seoul 125 - 126
Kim SH 2007 A study on the operation mechanism of Song I-Yong’s armillary clock Chung-Ang University
Kim SH 2009 The scientific and technological study on the operation mechanism of Yesandae The Chungbuk Sahak 22 25 - 67
Kim SH , Jung MH , Lee KW 2010 A study on reconstruction and design of Yesandae’s power supply mechanism The Chungbuk Sahak 24 115 - 138
Lee YS , Kim SH , Jeong JH 2009 Study on the clock manufacture during the Yi Dynasty JASS Cited by Jeon SW A new comprehend on the Korean history of science (Yonsei University Press Seoul 1998) 499-552. 26 355 - 374
Nam MH 1995 Korea Water-Clocks Konkuk University Press Seoul 75 -
Nam MH 2002 Jang Yeong-Shil and striking Clepsydra Jagyeongnoo: revival on the time measuring history ofJoseonperiod Seoul National University Press Seoul 52 - 58
Needham J , Lu GD , Combridge JH , Major JS 1986 The Hall of Heavenly records: Korean astronomical instruments and clocks 1380-1780 Cambridge University Press London 6 - 80