Abstract
LONDON. Chemical Society, March 2.—Dr. J. H. Gladstone, vicepresident, in the chair. The following papers were read:—The magnetic rotation and refractive power of ethylene oxLde, by W. H. Perkin. The magnetic rotation of ethylene oxide is remarkably low, and the refractive power is also below the calculated value.—The origin of colour (including fluorescence), vii. The phthaleins and fluoresceins, by H. E. Armstrong The author has previously taken exception to the formulæ usually assigned to phenolphthalein and its congeners; the exhibition of colour by these substances could not be accounted for by the formulæ generally ascribed to them. The correctness of the author's views has now been demonstrated by Bernthsen and Friedlädnder independently. The former chemist has shown that the rhodamines afford true ethereal salts, proving that they form carboxy-compounds and not lactone derivatives. Bernthsen also points out that the characteristic development of colour observed on adding alkali to phenolphthalein is probably due to the hydrolysis and subsequent conversion of the colourless lactone derivative into a quinolic compound; the latter then suffers dehydration, affording a coloured quinonoid derivative:—
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Societies and Academies. Nature 47, 551–552 (1893). https://doi.org/10.1038/047551a0
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DOI: https://doi.org/10.1038/047551a0