Abstract
American Journal of Science, June.—On the colour relations of atoms, ions, and molecules, by M. Carey Lea. Part II. If a coloured substance be formed by the union of a colourless kation with a colourless anion, the colour belongs to the molecule only. Consequently, if we find a solvent which, like water, is capable of separating the ions, the resultant solution when dilute must be colourless, no matter how intense the colour of the compound. Experiments confirm this law without exception. Antimony pentasulphide, a strongly coloured compound, is a case in point. When dissolved in an alkaline sulphide, the ions of antimony and sulphur, themselves colourless, separate sufficiently to no longer change each other's vibration periods. They still, however, remain within the sphere of mutual influence. The union of coloured and colourless ions gives rise to the most surprising changes of colour. Two similar coloured ions may unite to form a colourless element. Two similar colourless ions may unite to form a strongly-coloured element. No black ion is known. There is absolutely no relation traceable between the colour of an ion and that of the element which it aids to form.—The gravimetric determination of selenium, by A. W. Peirce. The usual method used in the gravimetric determination of selenious acid, that of precipitating the selenium with sulphurous acid in presence of hydrochloric acid, is slow and incomplete. The author substitutes potassium iodide for the sulphurous acid. To avoid obtaining the selenium in the pasty condition when large quantities are present, the potassium iodide should be considerably in excess of the amount necessary for precipitation.—The extinct Felidit of North America, by G. I. Adams. This is an attempt to give a general account of this family, to summarise the literature on the subject, and to work out a comprehensive classification. The paper is accompanied by three admirable plates.—The age of the igneous rocks of the Yellowstone National Park, by Arnold Hague. The pouring out of igneous rocks began with the post-Laramie uplift, or closely followed it, and from the time of the first appearance of these rocks, volcanic eruptions continued throughout Tertiary time.-Researches on the RSntgen rays, by Alfred M. Mayer. Herapathite, an iodosulphate of quinine, the most powerfully polarising substance known, is incapable of polarising X-rays. The actinic effect of X-rays varies inversely as the square of the distance of the sensitive plate from the radiant source.—On the Pithecanthropus ereclus, from the Tertiary of Java, by O. C. Marsh. It may be taken as established that the remains of this “missing link”at present known are of Pliocene age. The tooth, skull, and femur found belonged to the same individual. This individual was not human, but represented a form intermediate between man and the higher apes.
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Scientific Serials. Nature 54, 189–190 (1896). https://doi.org/10.1038/054189a0
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DOI: https://doi.org/10.1038/054189a0