Abstract
LONDON. Mineralogical Society, Mar. 20.—A. F. Hallimond: On the atomic volume relations in certain isomorphous series (2). The volume relations of compounds of calcium, strontium, barium, with oxygen, sulphur, selenium, and tellurium correspond in every way with those previously indicated for potassium, rubidium, caesium, sodium, lithium, and the halogens. The difference in the volume produced by the interchange of eutropic elements exhibits a constant ratio in each series. The partial volumes calculated for the radicles from the volumes of the free metals agree with those already obtained for the alkali compounds, and the values for oxygen and fluorine agree with those calculated by Wasastjerna from the refractive indices. The volume effect of substitution in the sodium chloride lattice varies somewhat with the size of the cell, but the variation never attains the extent required for a law of constant radii. Other isomorphous series agree with the Law of Retgers, and the present results are therefore expressed in terms of a law of additive volumes rather than additive radii.—A. Holmes and H. F. Harwood: On the age and composition of the Whin Sill and the related dikes of the north of England. The rocks of the Whin Sill and its associated dikes are quartz-dolerites of substantially identical composition. Dikes of this series run north of east. They are quite distinct from the system of tholeiite dikes to which the Bingfield dike, the ‘Brunton type’ of Teall, belongs. A pebble of quartz-dolerite in the Upper Brockram of George Gill, Brackenber Moor, near Appleby, has been proved by chemical analysis to be definitely of the Whin Sill type. This, with other evidence, indicates that the age of Whin Sill and its associated dikes is post-Westphalian and pre-Upper Brockram.—A. W. Groves: The identification of dumortierite in grains: dumortierite in Cornish granite. Dumortierite may be confused with a number of more common minerals. It is recorded in several sediments in southern England and in the Land's End granite.—T. V. M. Rao: On ‘bauxite’ from Kashmir, India. The so-called bauxite of Kashmir consists mainly of diaspore and an opaque mineral corresponding in composition to a monohydrate of alumina. The deposit was derived from beds of clay, having been first altered into the dihydrate (bauxite) and afterwards to its present condition through dehydration and thermodynamic metamorphism.
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Societies and Academies. Nature 121, 656–659 (1928). https://doi.org/10.1038/121656a0
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DOI: https://doi.org/10.1038/121656a0