HOSHINO Kasui (1885-1939), who graduated in mathematics from Tokyo Higher Normal School, wrote and published The Study of Geometry by the CHART System, a math study book for entrance exams, in 1929. Since then, the study books, which are named CHART System, have been published for over 75 years. Therefore, it can be said that the CHART System is an established method of study used in study books. However, there exists no previous research on the CHART System or its founder, HOSHINO Kasui. This paper clarifies the following two points: 1) Origin of the CHART System: The CHART System was developed by Hoshino Kasui in cooperation with his business involving the publication of a monthly magazine and several study books for entrance exams as well as through his managing and teaching experiences in a cramming school. 2) Features of the CHART System: The features of the CHART System become evident upon comparing the solution provided by Hoshino and that provided by a previous study book with regard to the same question. Hoshino led students to the solution by providing CHARTs, which were precepts based on solution scenarios that did not require dependence on rare inspiration. Hoshino's CHART System, which he extracted from numerous solution scenarios, was the first step in the compilation of solutions to questions in study books into a manual.
Although newtonian mechanics is the most familiar formulation of classical mechanics, we have an another one called variational mechanics. Leonhard Euler attempted to solve some mechanical problems using the latter idea and gave two variational-mechanical laws : "law of rest " in statics, and "law of motion " in dynamics. He maintained that these two laws were "in harmony ", namely that the one could be derived from the other. Moreover, they are both based on "principle of least action, " according to which some quantities are minimum in physical phenomena. In effect, "law of rest " asserts that the sum of "efforts " for bodies is minimum in equilibrium, which Euler interprets as the evidence of the intention of nature to "save efforts. " "Law of motion " determines the trajectory of a mass point, in which "action " is minimum; according to Euler, this could be explained by the inertia of bodies. These laws show Euler's faith in his principle, even though he doesn't use the condition of "minimum " in solving concrete problems; therefore, his "principle of least action " is not a mathmatical requirement. His demonstration of the "harmony " is also based on the belief that nature "saves efforts. " This attempt is, however, a failure in a double meaning; we can't prove the "harmony " from the point of modern view, and Euler's proof is inconsistent with his own "principle of least action. " "Euler's variational mechanics " has failed to realize a unified treatment of statics and dynamics, because it was built up on the "principle of least action. "
This paper examines the process and development of revolutionary data of thermal radiation in the late 19th century, focusing on Friedrich Paschen's experimental research in the early to mid-1890s. The well-known experiments of O. Lummer and E. Pringsheim, H. Rubens and F. Kurlbaum had brought about the suggestive results concerning Planck's radiation law. Paschen's research played an important role in pioneering experimentalists who were active in the early 1890s. Before Lummer, Pringsheim, Rubens, and Kurlbaum made a series of experiments on the radiation law, Paschen had begun to research on the "Normal Spectrum " representing the spectral distribution of radiation energy. He had made it to examine the spectrum of diffraction grating with the directions of H. Kayser in 1891-1892. In the meantime, other experimentalists such as Lummer and Rubens conducted research on the measurements of luminous intensity and electricity at the request of refining the standards. In 1893 Paschen improved the foundation for experiments on thermal radiation by utilizing those different kinds of measurements and made a step forward in the precision measurements of radiation distribution function.