On the corundum stone from Asia / [Charles Francis Greville].

  • Charles Francis Greville
Date:
[1798]
Catalogue details

Licence: Public Domain Mark

Credit: On the corundum stone from Asia / [Charles Francis Greville]. Source: Wellcome Collection.

    18/50 page 18
    The Corundum of China. Argillaceous earth 84 0 Siliceous earth 6 50 Oxide of iron 7 50 Loss 2 0 100 That the analysis of sapphire by Mr. Klaproth may be com¬ pared, it is here added. Argillaceous earth - 98 50 Calx of iron - 1 o Calcareous earth - o 50 100 Iron ore crystallized is often mixed with the Chinese Co¬ rundum, as I have before stated, and may be considered as accidentally interposed, not combined. In the Corundum of the Coast, the greenish colour may indicate the combination of iron, as the blue colour does in the sapphire; and the propor¬ tion of iron in both is nearly alike. There then is the 7^ and of silex in Corundum, evi¬ dently an integral part of the coarse Corundum crystal, and not of the sapphire; but it will require an analysis of the vitreous or pellucid Corundum, to decide that silex is a constituent part of Corundum : there will then remain to account for the calca¬ reous earth; and, having established its being a constituent part of the sapphire, the small proportion of cannot be expected to produce a very notable difference. It is not necessary to do more than thus to hint at what further analysis and examination of former experiments are
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