Kinoshita included in his objectives “to see whether a single 𝛂-particle produced a detectable photographic event”. His method was to expose the emulsion to radiation from a well measured radioactive source, for which the emission rate of 𝛂-particles was known. He used that knowledge and the relative proximity of the plate to the source, to compute the number of 𝛂-particles expected to traverse the plate. He compared that number with the number of developed halide grains he counted in the emulsion, taking careful account of ' background radiation ' that produced additional 'non-alpha' grains in the exposure. He completed this research project in 1909, showing that it was possible “by preparing an emulsion film of very fine silver halide grains, and by using a microscope of high magnification, that the photographic method can be applied for counting 𝛂-particles with considerable accuracy”. This was the first time that the observation of individual charged particles by means of a photographic emulsion had been achieved. However, that was the detection of individual particle impacts, not the observation of a particle's extended trajectory. Soon after that, in 1911, Max Reinganum showed that the passage of an 𝛂-particle at glancing incidence through a photographic emulsion produced, when the emulsion was developed, a row of silver halide grains outlining the trajectory of the 𝛂-particle; the first recorded observation of an extended particle track in an emulsion.