Hong Tae-Yong was both a philosopher and scientist in 18th century Korea. The fact that he proposed the roating earth theory is well known, but the appreciate for it has not been established. In this paper, firstly the previous investigations are surveyed and indicated a problem in there. In the many cases the originality is discussed in the connection with Copernican theory without the examination of Hon's own writing "Uisan mundap" mentioned the roating earth theory. Thus, secondly examinating "Uisan mundap" the characteristics of his roating earth theory and why Hong could propose his theory are considered. Hong's roating earth theory is a moment of the development into the infinite universe theory and a part of his cosmology. There his relativism and the mechanical viewpoint to nature played the important roles
The purpose of this study is to show why E. Huckel alone thought in the early 1930s that molecular orbital(M.O.) theory was better than valence bond (V.B.) theory. In order to elucidate it, the author has investigated the development of the electronic formula of benzene and has made clear the meaning of Huckel's quantum theoretical coutribution to the benzene problem.
In the early 20th century, chemists proposed several types of the electronic formula of benzene : the ionic bond type, the tetrahedral carbon model type, the three electron bond type, the aromatic sextet type,and others. They compared these electronic formulas one another, together with the considerations of the
experimental evidence. It was E.C. Crocker who first proposed the aromatic sextet type of electronic fonnula of benzene in 1922, although it is usually thought that R. Robinson first proposed that formula in 1925. Aromatic sextet had been recognized as one of the most reasonable structural hypothesis up to about 1930, and it was in a sense the revival of the old benzene problem, i. e., the difficulty of representation of the bonding state of benzene ring.
At that time, Huckel treated the benzene problem based on wave mechamics and recognized aromatic sextet as a closed shell which was the result derived from M.O. theory but not from V.B. theory. According to Huckel, the stability of aromatic sextet should be understood as resulting from the nature of the closed shell like such of noble gas. Since Huckel could solve the benzene problem which had been unsolved for about 75 years, he thought that M.O. theory was better than V.B. theory.
The author attributes rapid loss of the significance of aromatic sextet to the conflict between Robinson's and Huckel's view on, for example, induced polarities of substituted benzenes, to the critical opinion expressed by W.G. Penney, and to the imperfection of HuckeFs interpretation mentioned above.
Three water clocks of Han dynasty production are still in existece. All of them are made of bronze. In this treatise, I study them in detail and speculate on the circumstances of their actual use in the time of their production.
Then, on the basis of these existing water clocks and related documentary records, I examine the origin and the course of development of water clock.
Though, I don't specialize in the study of Japanese history, I additionally presents in this treatise a secondary review of Asuka water clock. For Asuka water clock, which was excavated recently from the ruins of Mizooch (水落)in Nara prefecture, a national institution has prepared a replica. I, however, believe that this peplica is not accurate. I therefore suggest an alternative water clock model which I think fits to the characteristics of the ruins.