Atmospheric Condensation Nuclei P. J. Coulier 1875 and J. Aitken 1880 (Historical Review)

P. J. Coulier in France and J. Aitken in England performed the first basic experiments and made the observations dealing with the role of fine airborne particles in vapor condensation processes. Coulier published his results in 1875 and Aitken published in 1880. They did almost the same experiments, obtained very similar results and provided similar explanations. Vapors condense on solid airborne nuclei. Nevertheless, Coulier had difficulty explaining some of his later results by the ''condensation nuclei hypothesis.'' He thought that this hypothesis was not generally valid. Aitken only saw Coulier's paper in 1881. He repeated some of Coulier's experiments and was then able to explain all of his and Coulier's results by means of the ''condensation nuclei hypothesis,'' which he considered as generally valid. This work has led to the continuing study of heterogeneous nucleation and the development of condensation nuclei counters.