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.

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The problem of the units of X-ray exposure originated from the fact that therapists wished to grasp the relationship between the quantity of irradiated X-ray and its effect on medical treatment, and to make a comparative study of each therapeutic result by the same measure. This problem was an interdisciplinary one between physics and radiotherapeutics. In 1925, the Radiological Society of North America settled the Committee on Standardization of X-ray Measurements to study the problem of measuring X-rays, and to guide the members of the Society. The committee was composed of physicists and radiologists in equal number. They developed a large-sized standard chamber and a portable one. L. S. Tayler transported the portable chamber to Europe and by using it he compared and exmined British, German and French standard chambers, confirming that each of them could be used as a common standard chamber. Based on these facts the ICRU presented the Annex to the recommendations of 1934 on the standard measuring apparatus. It was shown by physicists that the effect on the human body was not represented only by the quantity of irradiated X-rays and that a description of the quality of X-rays was indispensable. As radiologists' understanding deepend, they came to actively submit proposals to radiological societies in the 1930's. Taking their opinions into consideration, the ICRU recommendations which were practicable for medical purposes were issued in 1937. The effort of American and British radiological societies for a better solution beyond disciplines is suggestive in dealing with interdisciplinary issues.

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TAKANO Choei, one of the progressive scientists in Tokugawa Japan, wrote in around 1830 an essay entitled by Taisei-Jishin-Setsu (Remarks on Earthquakes in Europe). We find that the essay is Japanese translation of the article "AARDBEEVING " (EARTHQUAKE) of the academic dictionary in the Netherland, Nieuw en Volkomen Woordenboek van Konsten en Weetenschappen (New Popular Dictionary on Science) edited by Egbert Buys in 1769-1778. The article is as lengthy as 202 lines. A serious misunderstanding is found in TAKANO's translation, which would be overlooked but for the Dutch original. We point out also that the TAKANO's essay was copied, though slightly modified, in Rigaku-Teiyo the famous scientific book written by HIROSE Genkyo in 1856.

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