R. A. Millikanの電気素量の実在の検証 -cloud法から水の balanced drop 法, さらにoil-drop法（相対値e）への発展過程-

抄録

In this paper, clarified are the motivation leading the development and the contrivance featuring the processes of Millikan's verification of the elementary electrical charge, with the expectation as a case study for the new implication of the experimental researches in early 20th century physics. The controversy on the atomic theory, occurred in St.Louis Congress (1904), and Millikan's own photo-electric effect research drove him to the momentous question as to the reality of "the electron as the natural unit of electricity". Throughout his observational process ―"seeing the electron―, the confidence in and the limiting factors of his experimental apparatus are particularly noteworthy, as well as the active figures in his experimental methods in this period (1906-1911), especially in the process of converting the capture of ions by water droplets, found in the balanced method, into the core of his next oil-drop method. As to the process under consideration, his essential result was the direct verification of the atomic interpretation of both electricity and matter, confirmed independently of the uncertain theory of Stokes' law of fall of a small spherical body through a gas.