This study aims to develop a restoration model of an armillary sphere of Tongcheon-ui (Pan-celestial Armillary Sphere) by referring to the records of Damheonseo (Hong Dae-Yong Anthology) and the artifact of an armillary sphere in the Korean Christian Museum of Soongsil University. Between 1760 and 1762, Hong, Dae-Yong (1731-1783) built Tongcheon-ui, with Na, Kyung-Jeok (1690-1762) designing the basic structure and Ann, Cheo-In (1710-1787) completing the assembly. The model in this study is a spherical body with a diameter of 510 mm. Tongcheon-ui operates the armillary sphere by transmitting the rotational power from the lantern clock. The armillary sphere is constructed in the fashion of a two-layer sphere: the outer one is Yukhab-ui that is fixed; and the inner one, Samsin-ui, is rotated around the polar axis. In the equatorial ring possessed by Samsin-ui, an ecliptic ring and a lunar-path ring are successively fixed and are tilted by 23.5° and 28.5° over the equatorial ring, respectively. A solar miniature attached to a 365-toothed inner gear on the ecliptic ring reproduces the annual motion of the Sun. A lunar miniature installed on a 114-toothed inner gear of the lunar-path ring can also replay the moon's orbital motion and phase change. By the set of ‘a ratchet gear, a shaft and a spur gear’ installed in the solstice-colure double- ring, the inner gears in the ecliptic ring and lunar-path ring can be rotated in the opposite direction to the rotation of Samsin-ui and then the solar and lunar miniatures can simulate their revolution over the period of a year and a month, respectively. In order to indicate the change of the moon phases, 27 pins were arranged in a uniform circle around the lunar-path ring, and the 29-toothed wheel is fixed under the solar miniature. At the center of the armillary sphere, an earth plate representing a world map is fixed horizontally. Tongcheon-ui is the armillary sphere clock developed by Confucian scholars in the late Joseon Dynasty, and the technical level at which astronomical clocks could be produced at the time is of a high standard.

Hong, Dae-Yong manufactured the Tongcheon-ui (Pan-celestial Armillary Sphere) with cooperating clock researcher Na, Kyeong-Jeok, and its craftsman An, Cheo-In, in Naju of Jeolla Province in 1760 ~ 1762. Tongcheon-ui is a kind of astronomical clock with an armillary sphere which is rotated by the force generated by a lantern clock’s weight. In our study, we examine the lantern clock model of Tongcheon-ui through its description of the articles written by Hong himself. As his description, however, did not explain the detail of the mechanical process of the lantern clock, we investigate the remains of lantern clocks in the possession of Korea University Museum and Seoul National University Museum. Comparing with the clocks of these museums, we designed the lantern clock model of Tongcheon-ui which measures 115 mm (L) × 115 mm (W) × 307 mm (H). This model has used the structure of the striking train imitated from the Korea University Museum artifact and is also regulated by a foliot escapement which is connected to a going train for timekeeping. The orientation of the rotation of the going train and the striking train of our model makes a difference with the remains of both university museums. That is, on the rotation axis of the first gear set of Tongcheon-ui’s lantern clock, the going and the striking trains take on a counterclockwise and clockwise direction, respectively. The weight of 6.4 kg makes a force driving these two trains to stick to the pulley on the twine pulling across two spike gears corresponding to the going train and the striking train. This weight below the pulley may travel down about 560 mm per day. We conclude that the mechanical system of Tongcheon-ui’s lantern clock is slightly different from the Japanese style.

The famous Neo-Confucianist Zhu Xi considered that “Heart” was the cognitive subject and the practice subject, it was the cognitive object that every knowledge including human and all things on earth relations, but the most of all was the principle of morals such as filial piety, righteousness, loyalty and credit. Their relationship was that the cognitive object(every knowledge) was discovered and isolated by the cognitive subject(the wise heart). It can make “heart” and “all things on earth” concordant by exploring rule from thing(即物穷理), and can realize the subject's cognition to object. Hong Dae-Yong, as one of the representative abandoning Neo-Confucianism scholar, considered that “the practical heart” was the most important cognitive subject, it meant to take the practical matter and article as the object of cognition. Their relationship was that “the practical heart” as the object of cognition reached factual matters and factual articles and realized the subject's cognition to object. That is to say: we should put “the practical heart” into practice and reach cognition about factual matters and factual articles, so that we can innovative applications on reality(经世致用) and use everything to secure a better livelihood for people(利用厚生). As we can see the differences between Neo-Confucianism and Abandoning Neo-Confucianism from above three aspects content.

Zhuxi, who epitomized the thought of neo-Confucianism, not only has an effect on Chin ese idealist philosophy during the Song, Yuan, Ming and Qing dynasties,but has a direct i nfluence on Korean social philosophy during the Korean Age. Hong Tae-Yong is a well- k nown scholar in the later stage of the Korean Age, his theory with Zhuxi‘s became the tw o main schools on the Korean’s thinking. Zhuxi explored some problems in the field of epistemology with the theory of Ge Wu Z hi Zhi. Beyond that, he made a few opinions about verification theory and the opinions g et the clearer in his old age. He was becoming more interested in natural science, and th e thought about verification theory was frequently found in his later writings. In the resear ch about natural scientific problems, he had adopted observation, experimentation and pra ctice method. Zhuxi has opened up a new area and bends and laid the theoretical founda tions for verification theory. Hong Tae-Yong carried on some theoretical results of the Zhu xi on the one hand, and made his own pragmatical learning, on the other hand. In his th eory, the methodology occupied a central place. This thesis has taken the postivist theory as research objects, discusses about Hong Tae-Yong's pragmatical learning by comparing with Zhuxi's Verification Theory. He proved some opinions by the recognizing method of practice, observing methods and the recognizing method of practice. Hong Tae-Yong be d ivorced from Zhuxi's theory and have created a new pragmatical learning by these objecti ve methods. As has been described above, the main differences between the two is understanding th e “Shi(实)”. Hong Tae-Yong attaches great importance to truthful information, truthful circu mstances, truthful experiment and actual practice, He has made great efforts in recognizin g the real things, and has verified them one by one through practice. His objective metho d have helped take his thought off the ZhuZi's Philosophy and have created pragmatical l earning.

Honsangui (celestial globe) which is a water-hammering method astronomical clock is recorded in 「Juhaesuyong」 which is Volume VI of supplement from 『Damheonseo』, written by Hong Dae-Yong (1731~1783). We made out the conceptual design of Hong Dae-Yong’s Honsangui through the study on its structure and working mechanism. Honsangui consist of three rings and two layers, the structure of rings which correspond to outer layer is similar to his own Tongcheonui (armillary sphere) which is a kind of armillary sphere. Honsang sphere which correspond to inner layer depicts constellations and milky way and two beads hang on it as Sun and Moon respectively for realize the celestial motion. Tongcheonui is operated by the pendulum power but Honsangui is operated by water-hammering method mechanism. This Honsangui’s working mechanism is the traditional way of Joseon and it was simplified the working mechanism of Shui yün i hsiang t'ai which is a representative astronomical clock of China. This record of Honsangui is the only historical record about the water-hammering method working mechanism of Joseon Era and it provide the study of water-hammering method mechanism with a vital clue.