154 Additional Notice of Tungsten and Tellurium. 



slightly inclining to green, was obtained, and a black powder was 

 left behind. 



2. More acid digested on this powder, gave a deep red solu- 

 tion of iron, and left the yellow oxide of tungsten, which being 

 dissolved in ammonia, the black powder again appeared, and so 

 on, as under 3. Part III, 



3. Tne 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 

 eflfect, only more decidedly. 



5 . This precipitate, evidently an oxide of a metal, being col- 

 lected on a filter and dried, exhibited the following properties. 



6. Heated by the blow-pipe on charcoal, it was instantly vo- 

 latilized in part, and in part decomposed, with an almost explo- 

 sive effervescence; numerous ignited globules of metal appeared 

 on the charcoal, and burned with an abundant flame of a deli- 

 cate blue colour, edged occasionally with green. 



7. In many trials, these results always occurred, and sometimes 

 a peculiar odour was perceived, at first thought to be owing to 

 arsenic, but it was incomparably feebler, and somewhat resem- 

 bled that of radishes*. 



S. Zinc, iron, and tin, plunged into separate portions of the 

 nitro-muriatic solution, precipitated abundantly a black floccu- 

 lent substance. 



9. On charcoal before the blow-pipe this substance was very 

 combustible, with a blue flame, and was completelv dissipated in 

 the form of white oxide, with the above smell. 



10. Some of it was obtained on the charcoal in metallic glo- 

 bules ; it was a brittle metal, white, with a tinge of red, and 

 foliated, but not so distinctly as bismuth and antimony. 



11. The filters on which the white oxide had been deposited, 

 burned almost with explosion, nearly as rapidly as if they had 

 been soaked with nitrate of potash or of ammonia, and the cha- 

 racteristic blue flame appeared while the burning lasted. 



12. Other experiments were made upon the metal (not the 

 oxide). It gave to strong sulphuric acid (simply by standing in 

 it in the cold) an pmethystine colour, which disappeared as the 

 acid grew weaker, by attracting water from the air. 



* This was most remarkably perceived on one occasion, where, under the 

 idea that possibly chrome might exist in the ores, they had been intensely 

 heated in a forge along with pearl-ashes. The mass, when lixiviated, gave 

 only a greenish solution, becoming colourless by nitric acid, and again 

 greenish by an alkali ; this was supposed to be owing to iron and manga- 

 nese. No metal wss obtained, except a few minute globules of attractable 

 iron ; but the laboratory was filled with white fumes, having the peculiar 

 odour alluded to. 



13. With 



1 



