British Mineralogy; Or, Coloured Figures Intended to Elucidate the Mineralogy of Great Britain Volume 2

British Mineralogy; Or, Coloured Figures Intended to Elucidate the Mineralogy of Great Britain Volume 2

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1806 edition. Excerpt: ...having been deprived of their oxygen. These crystals are very extraordinary, as they comprehend the Octae'dron with truncated edges: they have also truncated and bevelled solid angles, making a very compound crystal: see the left hand figure. The intermediate varieties are the dodecacdron and octaedron, truncated at the solid angles. The VOL. II. I particles show some signs of being thread-like confused octaedrons, somewhat resembling those on the following plate, tab. 147-They are externally between a copper colour and red, scarcely metallic in the lustre, until cut, and then perfectly so. It is, as the Count de Bournon observes, useful in many instances to use a magnifier to examine crystals; and we should lose some very interesting beauties without it. These indeed may be pretty well seen by the eye alone, but it is admirable to observe how neatly these are formed by such help as the magnifying glass. We do not know of any other specimen of this kind. TAB. CXLVII. CUPRUM oxygenizatum. Filamentose Oxide of Copper, Div. 2. Imitative. Nature, ever various and instructive, often represents one thing with the appearance of another. Thus, a casual observer would expect that this Copper Ore merely consisted of filaments of scarlet silk: however, on examination with the help of a lens, we with certainty distinguish the contrary, and see how beautifully Nature varies her operations, and under certain circumstances accomplishes the same end with different appearances: thus, the moleculae are forming threads more or less discoverable in the shape of elongated octaedrons or cubes. Tlie upper figure is decomposing Feltspar and Quartz with these filaments of Ruby Copper Ore, some of which are in bent 4-sided threads crossing each other. Others are irregular...
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Product details

  • Paperback | 38 pages
  • 189 x 246 x 2mm | 86g
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236521021
  • 9781236521026