Abstract
LONDON. Royal Society, May 10.—A. Fowler: The series spectrum of trebly-ionised silicon (Si IV). Numerous new lines of silicon have been observed and have been classified in four groups representing successive stages of ionisation. They have been designated Si I, Si II, Si III, and Si IV. The spectra consist alternately of triplets and doublets, and the series constant has successive values N, 4N, gN, and 16N. For the series of Si IV the series constant is 16N. The spectrum is similar to that of neutral sodium, Na I. Including Paschen's recent work on Al III, and the author's previous work on Mg II, which also have spectra similar to that of Na I, data are thus available for the comparison of the spectra given by four similarly constituted atoms, which differ mainly in the charge of the nucleus. The highest limit of the Si IV system is 364,117, corresponding to an ionisation potential of 40.6 volts.— Sir R. Robertson and W. K. Garner: Calorimetry of high explosives. A calorimetric bomb was devised in which high explosives could be brought to true detonation under comparable conditions as regards density of loading and confinement, without using a large quantity of explosive. In an explosive balanced in respect to total combustion, where it is possible to calculate values for heat of detonation and volume of gases, the results agree with theoretical calculations. The influence of the higher heat of formation of phenol with respect to toluene is reflected in the similar values for heat of detonation of trinitro-phenol and of trinitrotoluene, although the latter has much less oxygen for its combustion. The nature of the products, and the effect of conditions under which detonation is carried out on heat generated, and gaseous reactions involved, chiefly with regard to liberated carbon, are discussed.— H. S. Hele-Shaw: Stream-line filter. Very thin films of coloured liquid, or liquid containing matter in very fine suspension, either lose their colour in one case, or become deprived of their suspended matter in the other, on entering such thin films. In the new form of filter, sheets of paper made impervious to the fluid containing the suspended matter are arranged in a pack. By perforating the pack with a large number of holes it is possible to get the equivalent of a number of sources and sinks. This was obtained by using high pressures, so as to force the matter from one row of holes, acting as sources between the interstices of the paper, to another row of holes, each hole in the latter acting as a sink. Filtration can be made sufficiently rapid for actual use. The colouring matter of various dyes, from what were apparently complete solutions, can be removed, and substances like peat-water rendered clear and colourless.—F. W. Aston: A critical search for a heavier constituent of the atmosphere by means of the mass-spectrograph. The residues absorbed in charcoal from more than 400 tons of air were dealt with. Analysis with the mass-spectrograph gives a negative result and indicates that such an element certainly does not exist to the extent of 1 part in 1015 of air, and probably not to the extent of 1 part in 2 × 1016 parts of air by volume. Faint bands observed in the region corresponding to masses 150 and 260 were found. The first is due to a complex molecule of mercury with a multiple charge, but no conclusion is reached in the case of the other. The results of the experiments are not in accordance with the presence of molecular krypton and xenon in the air, recently suggested.—H. E. Armstrong: The origin of osmotic effects. IV.—Hydronodynamic change in aqueous solutions. “Water” is a complex saturated with the gas Hydrone, OH2. Primarily, hydrone is the sole potentially “active” constituent, but it becomes actually active only under conditions which suffice to determine electrolytic change. The vapour pressure either of water or of a solution is the measure of the proportion of free hydrone molecules present in the liquid. Although the vapour pressure is lowered in the presence of any solute, the solution acquires attractive properties. The internal activity is increased while external activity is diminished. The effect produced may be ascribed to an interaction of molecules of the solute and those of hydrone. From non-electrolytes (under the influence of conducting impurity) a simple hydrol
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Societies and Academies. Nature 111, 689–692 (1923). https://doi.org/10.1038/111689a0
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DOI: https://doi.org/10.1038/111689a0