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. 1810 edition. Excerpt: ...salt are more effectual. The yellowish brown, though it retains its colour in a strong heat, yet melts at 150 or 160. Hence these two appear to differ. Mr. Bergman attributes to the yellower sort, 0,40 of argill, 0,25 of silex, 0,20aerated calx, and 0,13 of iron; and Mr. Achard, 0,4133 argill, 0,2166 silex, 0 ...
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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. 1810 edition. Excerpt: ...salt are more effectual. The yellowish brown, though it retains its colour in a strong heat, yet melts at 150 or 160. Hence these two appear to differ. Mr. Bergman attributes to the yellower sort, 0,40 of argill, 0,25 of silex, 0,20aerated calx, and 0,13 of iron; and Mr. Achard, 0,4133 argill, 0,2166 silex, 0,20 calx, and 0,1333 of iron. I found a compound, formed as Mr. Bergman-s result, to form a grey mass not well melted at 144, yet glazed at the surface; which shews that a few degrees more would effect its fusion, or, perhaps, the same degree, if longer continued. 10th Species.--Garnet.--Of this we have three varieties. 1st Variety.--Oriental Garnet. Carbuncle.--This is so called, not from its being found only in the eastern countries, but from its greater perfection; viz. hardness, lustre, and transparency. Its colour, deep or blood red, yet inclining to violet. Its internal lustre, 3 or 4. Transparency, 4, Double refraction. Crystallized, and presenting either 12 rhom-Mem. Stock. 1768. Q 2. boidal boidal planes, or 24 trapezoidal, or 36 planes, of which 12 are rhombs, and the 24 others elongated hexagons, interposed between these rhombs, and some other variations. Fracture, conchoidal. Hardness, 14 or 13. Specific gravity, from 4,000 to 4,188. 2nd Variety.--Common Garnet.--Deep red, inclining to violet, or verging to black, or olive, or leek green, or brown, seldom yellow. Its external lustre casual, internal 2.3. Transparency, 2.3.1. Of the brownish and blackish, most frequently, 0. Of the green at most, 2. Crystallized as the former variety, the surface of the crystals often diagonally seamed, frequently found also in rough rounded grains, or fragments. Fracture uneven, inclining to the conchoidal, flat or imperfect, often to the...
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