著者

山崎 正勝

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.40, no.218, pp.87-96, 2001 (Released:2021-08-17)

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Soon after the dropping of the Hiroshima bomb, Yoshio Nishina, an experimental physicist who was in charge of the Army's development of nuclear weapons at Riken, the Institute of Physical and Chemical Research, could understand that it was an atomic bomb because its energy release given in Truman's statement coincided with the one that his colleague Hidehiko Tamaki estimated a few years ago. This suggests that they knew of the magnitude of nuclear explosions. Uraniumu bakudan (uranium bomb), Japanese physicists' bomb at the time, is, however, known to be a kind of nuclear reactor out of control. The "bomb" of this kind is not very powerful because it is based on a slow-neutron reaction. This paper challenges to reproduce Japanese physicists' calculations at the time, and shows that they thought that they could explode their uraniumu bakudan, a slow- reactor bomb, with a quite high efficiency. This led them to expect that the energy release from their bomb would be of 20 K ton TNT equivalence that accidentally coincided with the energy release of the Hiroshima bomb.

著者

株本 訓久

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.40, no.218, pp.97-103, 2001 (Released:2021-08-17)

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In this paper, the author investigated how S.Shinjyo established his conception of the nature of our Galaxy and of spiral nebulae. S.Shinjyo founded the Institute of Cosmical Physics at Kyoto Imperial University, the second laboratory of astronomy in Japan. From 1915 to 1927, he studied the theoretical stellar evolution and established the eccentric nucleus theory that explained how the Cepheid Variables changed their brightness. In his papers, he mentioned not only stellar evolution but also the nature of our Galaxy and of spiral nebulae. Many astronomers were doing similar work at this time. The author focuses our attention to 18 papers by S.Shinjyo. It is important not only to investigate his papers so as to track the establishment of his conception but also to look at other contemporary Japanese papers on conception of the nature of our Galaxy and spiral nebulae. In his 1915 paper, he wrote that our Galaxy has a diameter of 6,600 light years and a spiral structure, and that spiral nebulae is anoter Galaxy. The 1916 paper proposed that our Galaxy didn't have a spiral structure but an ellipse structure. In the 1922 paper, he extended our Galaxy's diameter to 30,000 light years and introduced Shapley's conception of the nature of our Galaxy. In 1925, S.Shinjyo applied Shapley's conception and showed that the spiral nebula is not another Galaxy but rather a large meteoric group. In 1927, S.Shinjyo introduced Hubble's study of M31 explaining that it is 1,000,000 light years away and 45,000 light years in diameter. This means that he agreed the spiral nebula was indeed another Galaxy. Shapley's and Hubble's works influenced S.Shinjyo's work on spiral nebulae. This didn't mean that S.Shinjyo only followed the tendency of international astronomy. He integrated these conceptions, because they were not incompatible with his stellar evolution. But, this literature review generally shows that observational astronomy in Japan depended on the research tendencies of large telescope observational astronomy in America.

著者

株本 訓久

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.40, no.218, pp.104-106, 2001 (Released:2021-08-17)

著者

矢島 道子

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.40, no.218, pp.107-110, 2001 (Released:2021-08-17)

著者

小柳 公代

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.40, no.218, pp.111-115, 2001 (Released:2021-08-17)

著者

後藤 邦夫

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.40, no.218, pp.116-117, 2001 (Released:2021-08-17)

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.40, no.218, pp.118-126, 2001 (Released:2021-08-17)

著者

吉田 省子

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.40, no.219, pp.129-136, 2001 (Released:2021-08-16)

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Astronomer Kiyotsugu HIRAYAMA (1874-1943), known for his discovery of the families of asteroids in 1918, advocated the explosion theory that any families of asteroids were formed out of the breakup of a single large asteroid. Since, however, he had no decisive astronomical evidence for the theory, he asked experimental physicist Seitaro SUZUKI (1887-1977) to carry out experiments in SUZUKI's laboratory to obtain the data which support the theory. In response, SUZUKI conducted from 1931 1938 a series of experiments to destroy balls (made of sealing wax, clay and chalk) and investigated the relation between the sizes of fragments and their numbers by varying the impulse given to the balls. The destruction of balls was meant to be an analogue of the destruction he assumed of asteroids. Comparing experimental results obtained in the laboratory and the observed SIZE distribution of asteroids, he could only show that the explosion theory for the origin of the asteroids was a little more preferable to the alternative, collision theory. Both HIRAYAMA and SUZUKI had shared common interest in explaining astronomical facts by employing experimental results obtained in laboratories. However on the other hand, there was a small but significant difference in their focal points. Astronomer HIRAYAMA wanted to know specifically the origin of the families of asteroids, while physicist SUZUKI was interested in the origin of asteroids themselves in a broader perspective. In fact, SUZUKI had carried out in 1921, without any astronomical interest, some experiments he conducted in 1930s were motivated by his astronomical interest, they were an exteded version of those earlier experiments.

著者

株本 訓久

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.40, no.217, pp.12-23, 2001 (Released:2021-08-17)

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The purpose of this paper is the assessment of K. HIRAYAMA's study of Cepheid variable stars in Japanese and in the international trend of studying the variable stars. K. HIRAYAMA published four papers about variable stars in 1931 and in 1932, and he formed the contact theory which was one of the non-pulsation theories of Cepheid variable stars. S. SHINJYO, who was the Japanese researcher of Cepheid variable stars before K. HIRAYAMA, published five papers about variable stars from 1922 to 1926, and he formed the eccentric nucleus theory which was one of the non-pulsation theories of Cepheid variable stars. It was interesting to note that those researchers formed the non-pulsation theory after H. Shapley's study of the pulsation theory of Cepheid variable stars in 1914 and A.S. Eddington's study of the pulsation theory of Cepheid variable stars in 1919. S.SHINJYO and K.HIRAYAMA formed these non-pulsation theories in order to explain not only mechanism of the variable stars but also the energy source of stars and the stellar evolution. We concluded that their study of these non-pulsation theories was one of the evidence that the pulsation theory was established during 1930's at which the energy source of stars and the stellar evolution were established.

著者

玉川 達夫

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.40, no.217, pp.35-38, 2001 (Released:2021-08-17)

著者

小林 龍彦

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.40, no.217, pp.39-40, 2001 (Released:2021-08-17)

著者

後藤 邦夫

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.40, no.217, pp.41-48, 2001 (Released:2021-08-17)

著者

鈴木 善次

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.40, no.217, pp.49, 2001 (Released:2021-08-17)

著者

梶 雅範

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.40, no.217, pp.50-52, 2001 (Released:2021-08-17)

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.40, no.217, pp.53-63, 2001 (Released:2021-08-17)

著者

平井 浩

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.40, no.218, pp.65-74, 2001 (Released:2021-08-17)

著者

本間 栄男

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.39, no.216, pp.202-210, 2000 (Released:2021-08-23)

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During the collaboration of Beeckman and Descartes at Breda (1618-1619), they studied problems of mixed mathematics by so-called "physico-mathematica". In this paper I clarify the meaning of "physico-mathematica" for Beeckman especially in his musical theory. Beeckman considered the "physico-mathematica" as a way of giving the corpuscular interpretations both to the examples Descartes submitted to him (such as consonance and resonance) and to the problems of the musical theory (division of octave) which have been already demonstrated in the mathematical form by Descartes. This way of philosophizing depended on Beeckman's corpuscular theory of sound which he thought was a sequence of beats (ictus) of corpuscles of air. In those musical problems Beeckman acted as the "physico-mathematician" and Descartes as a traditional mixed mathematician.

著者

安孫子 誠也

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.39, no.216, pp.211-216, 2000 (Released:2021-08-23)

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There are two versions of the Japanese text of Einstein's "Kyoto Address." One is the original text by Jun Ishiwara, the physicist-colleague and translator of Einstein's, and the other is its revised version by one of Ishiwara's sons. It is pointed out that the existing English versions of the "Kyoto Address" are made by the translation from the revised version, which is somewhat different from the original. The other point made is related with the argument by Ryoichi Itagaki that the description in Kyoto Address on Einstein's knowledge of Michelson's experiment should be regarded as written in the subjunctive mood and does not correspond to the reality. But, this interpretation is against Ishiwara's own text and also to Einstein's own love letter to Maric in 1899.

著者

任 正爀

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.39, no.216, pp.217-222, 2000 (Released:2021-08-23)

著者

小川 束 小林 龍彦 佐藤 賢一 藤井 康生 佐藤 健一

出版者

日本科学史学会

雑誌

科学史研究 (ISSN:21887535)

巻号頁・発行日

vol.39, no.216, pp.223-229, 2000 (Released:2021-08-23)