The paper describes a history of metal spraying in Japan before the Second World War.
In 1916, M.U.Schoop was granted a basic patent for the metal spraying in Japan.
In 1921, K.Ezawa had begun the commercialising of the metal spraying in Japan. In 1923, T.Ezawa had been granted a patent for the metal spraying used electric arc gun. In Japan, this process was used since.
In spite of these successes, in 1921-1935, the metal spraying was not used extensively and a remarkable technical progress did not take place in Japan. Little attention was directed to improving the quality of the spray coated film at this stage.
In the latter half of the period 1921-1945, the use of the metal spraying extended in Japan. This process made a progress with regards to both the applications in practice and the researches in laboratory. Nevertheless, the metal spraying was looked upon with some scepticism in those early days because the adhesive strength of the spray coated film to a substrate was quite small.
In Japan, a real advance in the use of the metal spraying take place after the Second World War.
Recently some considerations on batteries of Shozan Sakuma (1811-1864) have been given by several scholors, but there is still posibility of further study on this subject. The aim of this paper is to investigate the following matters :
Firstly, we clarify what kind of battery was one described in Sakuma's letter, and secondly we investigate what Dutch literature Sakuma made his existing battery based on.
Finally, we survey Japanese books published before 1858 in which batteries were described and make a comparative study of Sakuma's battery, in order to know how batteries had been spread in Japan at that time
Einstein introduced the spontaneous process of "outgoing" radiation in 1916, corresponding to the radiation emitted from an oscillating Planck resonator. In 191& Bohr suggested that the probability coefficient of spontaneous emission could be determined by the amplitude of the multiply periodic system. The correspondence principle, however, enabled one to indicate only an asymptotic relation(13)(in the text) in the limit of high quantum numbers, and was powerless to fix the unique form of the amplitude valid for all quantum numbers. Kramers gave up determining the amplitude in terms of the multiply periodic system, and regarded Eq.(26)as quantum-theoretically valid relation. Then he reversed Eq.(26)and took the relation(27)as the definition of the characteristic amplitudes of the virtual oscillators. Eventually, Kramers' dispersion formula was the first fruitful attempt to embody Einstein's probability coefficient of the spontaneous emission in the form of the "strength"（f=A･γ) of the virtual oscillator.
In the 1920's, R. Robinson and C.K. Ingold controverted on principles of an electronic theory of organic reactions. They had been investigated how to theorize reactivity of many complicated organic reactions from different points of view―polar (Robinson, alternative polarity) and non polar (Ingold,free affinity).
Gradually they were conscious of necessity of new concepts (electron valence) for showing quantitative reactivity in this controversy on nitration reactions of nitrosobenzene and benzilamine etc. from 1924 to 1926.
The year,1926, was the turningpoint that they indicated new concepts of reactivity of organic reactions―the density of electron around atoms (Robinson) and the electronic strain around atoms(Ingold). So, they could publish the electronic theory of organic reactions in 1930's.
Consequently not only Robinson but also Ingold in this controversy played an important part for forming basic concepts and methods to quantiy their reactivities in the electronic theory of organic reactions.