B. remark.
We had been for some time inclined to believe, that the above ore was ferruginous tungsten, but although fortified by the opinion of Col. Gibbs, we were withheld from announcing it, because the form of the crystals, the specific gravity, the colour, and perhaps some other characters, were not perfectly accordant with European descriptions, and with the specimens in our possession, which are from Saxony and Cornwall.
During the necessary chemical trials (which have, we trust, established the correctness of the above opinion,) we very unexpectedly discovered in some of the ores of tungsten, proofs of the existence of tellurium. The conclusion was induced by the phenomena, for nothing was farther from our expectations.
Two fragments were pulverized by an assistant, and we therefore cannot say whether they had any external characters different from those of the other pieces; they came, however, from the same part of the vein, and their powder resembled that of the other pieces.
1. Digested in nitro-muriatic acid, a straw-yellow solution, slightly inclining to green, was obtained, and a black powder was left behind.
2. More acid digested on this powder, gave a deep red solution of iron, and left the yellow oxyd of tungsten, which being dissolved in ammonia, the black powder again appeared, and so on, as under 3. Part III.
3. The solution 1, diluted largely with water, deposited an abundant white precipitate, which was very heavy and rapidly subsided.
4. Alcohol and ammonia, respectively produced the same effect, only more decidedly.
5. This precipitate, evidently an oxyd of a metal, being collected on a filter and dried, exhibited the following properties.
6. Heated by the blow-pipe on charcoal, it was instantly volatilized in part, and in part decomposed, with an almost explosive effervescence; numerous ignited globules of metal appeared on the charcoal, and burned with an abundant flame of a delicate blue colour, edged occasionally with green.