Societies and Academies


    LONDON. Royal Society, Feb. 19.—A. J. Allmand and L. J. Burrage: The discontinuous nature of the process of sorption of gases and vapours by porous solids. A summary is given of results obtained either at low pressures or by a new ‘retentivity’ technique, indicating the presence of discontinuities in the adsorption isothermals and isosteres of vapours on charcoal. The technique is described of a simple static method for the determination of adsorption isothermals, which permits of the detailed examination of a limited pressure range being rapidly carried out. Breaks in the isothermals were found in all cases. Measurements with silica gol and with benzene, carbon tetrachloride, and water also showed discontinuities, rudimentary or slight in the first two cases, but very pronounced with water. A viow of the mechanism of the adsorption process is outlined which has features in common with Polanyi's modified theory and with recent suggestions of Semenoff. Distinctions are made between tho behaviour (a) of activated charcoal and of silica gel and (b) of water (molocules natural dipoles) and of carbon tetrachlorido (molecules without dipole moment).—L. N. G. Filon and F. C. Harris: The photo-elastic dispersion of vitreous silica. Double refraction was measured for a series of well determined wave-longths, the load on the specimon remaining unaltered throughout each sot of observations. The results show: (1) that the law of photo-elastic dispersion in silica varies slightly with the load applied, so that tho usual assumption that the double refraction is proportional to the stress cannot in this case be exactly true; (2) that the curve of photo-elastic dispersion shows marked and highly localisod oscillations; (3) that these oscillations are very probably due to some natural periods of the molecules.—C. G. Darwin: Examples of the uncertainty principle. Observations with electrometers and magneto-meters conform to the uncertainty principle of Heisonberg.—G. B. Deodhar: Some investigations in Rontgen spectra. (1) The Ka. and Kp groups of the elements silicon, phosphorus, sulphur and chlorine have been studied.—(2) A large number of sulphur compounds havo been examined, and it is found that considerable changes in the relative intensities of tho fll and 0, lines take place from substance to substance.—(3) Tho fine structure of the K-edge of silica is recorded and measured by using quartz as the analysing and absorbing substance. The observed fine structure may result from the ejected K-clectron stopping in one of the possible virtual electron orbits in the SiO2 molecule, as has been suggested in the investigation of the spectra of sulphur compounds.

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    Societies and Academies. Nature 127, 329–331 (1931).

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