Jgg EXPERIMENTS ON MOLYBDENA. 



the metallic state, before other experiments had given me far- 

 ther light respecting its nature, I resolved to employ the dis- 

 oxigenizing action of ammonia, to obtain metallic molyb- 

 Ammonia ex- dena. 1 took six ounces of liquid molybdate of ammonia, 

 pelledby heat: j^j^j evaporated to dryness. During the evaporation it 

 residuum co- diffused a smell much resembling that of vanilla. The saline 

 chrcoal'^ residuum was pressed tight into a small glass of a convenient 

 form, and covered with a layer of charcoal dust ; the glass was 

 and exposed to bedded in sand in a crucible; and this was set on the fire. After 

 a strong heat, ^j^^ ammonia was volatilized, the glasa was closed with a chalk 

 stopple, the fire urged briskly, and the crucible kept for half 

 Product. an hour in a strong red heat, which melted the glass. After the 



whole had grown cold, a tolerably compact mass was found, 

 easily reducible to powder, of a copper colour inclining in 

 some places to blue, with a metallic lustre, and exhibiting 

 crystalline lamince. It weighed three drachms. 

 Attempt to To see whether this mass would not fuse into a button in a 



use u mo a stronger heat, I pounded it; rammed the powder, which was 

 of a violet colour inclining to copper red, tight into a cruci- 

 ble lined with charcoal; covered it with a finger's breadth of 

 charcoal powder; closed the crucible well ; and kept it for 



but merely ag- half an hour at a white heat in a forge fire. Ai'ter cooling 

 glutinated. , i ■ , • i i •. 



the mass was agglutinated in places where it was most expo- 

 sed to the action of the fire ; but in the middle it was pul- 

 verulent, and had retained its colour. 

 rxperiment JLxps. p and 10. Desirous of repeating the preceding expe- 



repeated witha j-jments with a greater heat, I put some molybdate of ammo- 

 stronger heat. ° '^ ■' _ 



nia into a Hessian crucible. After the ammonia had been 



expelled by a moderate heat, I covered the mass with a stra- 

 tum of charcoal, closed the crucible, increased the fire to a 

 white heat,and kept the crucible in this state half a hour. After 

 Product. cooling a compact mass was found of a violet brown colour, 



tlie lower part of which, that was in contact with the bottom 

 of the crucible, and had consequently experienced a stronger 

 heat, was toleiably consistent; it could not be reduced to 

 powder without difficulty. This powder was of a violet co- 

 lour, and appeared to consist of a multitude of small crys- 

 talline scales of a metallic brilliancy. The fissures that tra- 

 versed the mass in every direction exhibited on their sides a 



great 



