Abstract
ON Tuesday, Nov. 15, M. Paul Panllevé, professor of celestial mechanics at the one, and French Minister for War gave evening discourse at the Royal Institution a large audience. M. Pain-levé's lecture took the of a general review of the evolution of scieitific conceptions on the structure of matter from the early speculations of Greek philosophers down to the most recent and advanced the . He pointed out that this problem resides essentially in a change of scale, and put the question as to whether matter would appear continuous or discontinuous if our senses were refined far beyond the range of our most powerful instrument—the famous controversy of plenum versus vacuum. In turn, continuity and discontinuity have seemed to prevail as an explanation of matter and of light. The atomic theory, and the corpuscular emission of light on one hand, and on the other hand thermodynamics and the theory of luminous waves, are characteristic of these two tendencies. Turning to the question of the reality of molecules, M. Painlev referred to the great number of very diverse methods agreeing to a remarkable degree of accuracy in their result as to the number of molecules in a unit weight, and mentioned in this connexion the researches of Prof. Perrin on tim Brownian movement. He then dealt with the atomic microcosm, showing that the study of corpuscular radiations forces us to introduce the idea of discontinuity inside the atom and to regard all matter as made up of two final elements only—the electron and the proton. Towards the end of the lecture, M. Painlevé mentioned the difficulties which lie in the way of explaining the luminous spectra emitted by atoms, and expressed the hope that the new mechanics, by associating material corpuscles with these mysterious waves, would ultimately overcome those difficulties. He showed a series of interesting slides illustrating points which he had discussed in his lecture, such as atomic impacts and coloured regions with well-marked outlines indicating differences of molecular thickness in soap films. The audience frequently expressed appreciation of the lecturer's eloquent exposition of his subject.
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[News and Views]. Nature 120, 777–781 (1927). https://doi.org/10.1038/120777b0
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DOI: https://doi.org/10.1038/120777b0