EXPERIMETJT3 ON WOLYaOEKA. JgT 



luted, explosions took place, by which some of the molyb* 



die acid was thrown about. 



To prevent these accidents, I made the trial again in wide- ^ third 

 mouthed capsules. ! took a hundred grains of powdered 

 metal, and poured on it an ounce of nitric acid diluted with 

 half an ounce of water. In a few minutes a very powerful 

 action took place, and the liquor became of a yellowish red. 

 inclining to brown. The whole of the metal not being dis- 

 jjolved, when no more gas was evolved i ^dded half an ounce 

 of acid, and placed the solution on a sand bath. The whole 

 vvas now dissolved, bnt the liquor remained of a yellowisii 

 red inclining to brown as before, only a reddish white pow- 

 der ai)peared swimming in it. I evaporated the mixture to 

 dryness, stirring it constantly. The residuum had a red 

 copper colour, mixed with a great deal of white; on continu- 

 ing the heat the surface acquired a grayish blue, the edges 

 a brown red, and in some parts an orange yellow. 



Thus it was evident, that the difference of colour exhi- showed that 



bited bv the oxigenized molvbdena was not occasioned bv ^^^'^^^^'^''^ 

 , i • 1 • 1 • 1 * 1 ~ 1 -T , -..^ not concerned 



charcoal mixed witli it, but might be ascribed to different in it. 



degrees of oxidariou of the metal. It is surprising, that the Thesulphuret 

 molybdena should become oxigenized so imperfectly in this more easily 

 manner; while its oxigenation is accomplished much more ^^^ ^^^^j^ *° 

 speedily and completely, when sulphuret of molybdena is 

 employed. To produce a perfect oxigenization, I poured 

 half an ounce of nitric acid on the dry mass, and heated it. 

 Finding no perceptible change take place, I added two 

 drachms of pure muriatic acid, which expedited the effect, 

 the mass became more and more compact and lighter co- 

 loured, and at length was white. Being dried and carefully 

 collected, it was kept at a red heat in a glairs capsule for a 

 quarter of an hour, left to cool, and weighed. Its weight 

 was now 145 grains, to which must be added three for what 

 adhered to the sides of the capsule, so that in this experi- 

 ment a hundred grains of molybdena bad absorbed 48 grains 

 of oxigen. In 100 parts of acid therefore there are 32*43 

 of oxigen. 



This experiment then gives a result differing little from Exp. 14 re- 

 those obtained in the I4th and 18th, I repeated the first P^''^'^'^' 

 once more. Taking a piece of fuaed moiybdic acid, that 



■weighed 



