Abstract
LONDON. Mineralogical Society, January 14.—Mr. W. Barlow, past-president, in the chair.—A. Hntchinson: Stereoscopic lantern-slides of crystal pictures. The twin pictures are projected by means of a double lantern through screens of complementary tints-red and green-and are, viewed through similarly tinted screens, one for each eye. If the adjustment is correct, a black-and-white picture stands out in relief. This method admits of the properties of crystals and of crystal-structure being demonstrated simultaneously to a Targe number of students.—L. J. Spencer: Mineralogical characters of turite (= turgite) and some other iron-ores from Nova Scotia. The mineral collection of the late Dr. H. S. Poole, which was presented to the British Museum in 1917, contains, amongst the iron-ores, specimens of magnetite, hcematite, turite, goethite, limonite, chalybite, mesitite, and ankerite from many well-defined localities in Nova Scotia. The dehydration curves and optical characters of turite (2Fe2O3, H2O), goethite (Fe.Oa.H.O), and limonite (2Fe3Os, 3H2O) grove that these, at least—strongst the large group of ferric hydroxide minerals, are distinct species with crystalline structure; some others are colloidal. Turite (= turgite, an incorrect German transliteration from the Russian) is a hard, lustrous, black mineral, with a radially fibrous and concentric, shelly structure, and gives a dark cherry-red streak; the fibres are optically birefringent and strongly pleochroic. Sharp, brilliant crystals with the forms of goethite, but consisting of anhydrous ferric oxide, i.e. pseudomorphs of hasmatite after goethite, were described.
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Societies and Academies . Nature 102, 418–420 (1919). https://doi.org/10.1038/102418a0
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DOI: https://doi.org/10.1038/102418a0