£00 Method of extracting Molyldk Acid 



acid. The alkaline earths, and earths which with the ino- 

 lybdic acid form salts ditficult of solution, could not answer 

 my purpose to separate the acid from the insoluble sub- 

 stances with which they are mixed. It remained to try- 

 soda and ammonia, which I found to be both equally pro- 

 per under circumstances peculiar to each of them, ior ac- 

 complishing the proposed end. 



Expcrinwnt X. 

 I boiled two gros of calcined molybdena with eight ounces 

 of water^ and instilled into the solution a ley of carbonate of 

 soda until no more effervescence took place. An excess or 

 alkali was added, and the matter was left to boil for half an 

 hour: it was then filtered, and the concrete matter which 

 remained on the filter was edulcorated. The different li- 

 quors were evaporated to two ounces, and nitric acid to 

 excess was instilled into the warm liquid. During the in- 

 stillation of the nitric acid a crystalline white powder was 

 deposited, and alter cooling there were formed in the liquor 

 crystals of a certain size. A new quantity was obtained by 

 evaporation. The difierent salts were washed and dried. 

 The residuum on the filter, after being washed and dried, 

 weighed thu'ty grains, and had the reddish colour of oxide 

 of iron. 



Experiment XI. 



The preceding experiment was repeated, with this differ- 

 ence : the liquor, after the effervescence had ceased, was 

 boiled for half an hour longer. The matter, after being re- 

 duced to two ounces, and filtered, was suffered to cool be- 

 fore the nitric acid was added. The addition of this acid 

 caused to be precipitated a larger quantity of the white pow- 

 der, which had a more crystalline aspect, and which after 

 edulcoration and desiccation had the splendour of mother- 

 of-pearl. As I did not add so much acid in this experi- 

 ment as in the former, the liquor was less charged with 

 niolybdic acid. The residuum, when washed and dried, 

 weighed also thirty grains. 



As I suspected that this residuum might contain a por- 

 ^tion of moiybdx acid less soluble than the preceding, I tried 

 to extract this acid by boiling the residuum with nllnc acid. 

 With this view I made the follouuig experiment. 



Experiment XII. 



The thirty grains of the residuum of the two last experi- 

 ments were boiled with an ounce of nitric acid of the spe- 

 cific gravity l"25Q and half an ounce of water, until the 



whole 



