Examination qfthe.DiopsideofFassa in the Tyrol. 355 



cipitate. This when made red-hot amounted to 0*0024 gramme, 

 and consisted of deutoxide of manganese, which reduced to 

 oxide, according to the proportion of these two oxides as- 

 sumed above, is equal to 0*0022 gramme of oxide of man- 

 ganese. 



The reason of this small quantity of manganese yet being 

 found, is the facility with which, on its being separated from so- 

 lutions by means of chlorine, a small portion of it is redissolved, 

 when the precipitate is left in contact with the fluid beyond 

 the time necessary for its formation, during which a little mu- 

 riatic acid may be produced. 



k. The nitric solution of Jime was now, while boiling, mixed 

 with caustic ammonia and carbonate of ammonia. The pre- 

 cipitated carbonate of lime gave, after heating, 0*6064 gramme 

 of pure caustic lime, which was completely soluble in greatly 

 diluted nitric acid, and with little effervescence. 



As in precipitating the lime with carbonate of ammonia, 

 especially without a sufficient addition of caustic ammo- 

 nia, small quantities may easily be left suspended, and the 

 carbonate of lime not being quite insoluble in the water used 

 for washing it ; — the solution having been much boiled down, 

 was again tested with oxalate of potash, and by means of it a 

 little more oxalate of lime was precipitated, but which, when 

 made red-hot, yielded only 0*0150 gramme of caustic lime. 

 Consequently the entire quantity of pure lime separated amounts 

 to 06064. + 0*01 50 = 0*6214 gramme. 



i. In order to separate the magnesia from the solution 

 (g),the former was acidulated with muriatic acid, concentrated 

 by boiling, and mixed with phosphate of soda and caustic 

 ammonia. At the expiration of about twenty-four hours the 

 crystalline deposit was collected and heated : it weighed 1*1790 

 gramme. 



After a second similar treatment, rendered necessary by the 

 easy solubility of the substance in a large quantity of water, 

 even if the latter should be mixed with some caustic ammonia, 

 which may perhaps itself promote the solubility by the access 

 of carbonic acid from the atmosphere, — another precipitate was 

 obtained weighing, after being heated, 0*0582 gramme. Con- 

 sequently the whole of the phosphate of magnesia obtained 

 amounts to 1*2372 gramme ; in which, if 100 parts of this salt, 

 heated, indicate 37 parts of magnesia*, 0*4577 gramme of 

 the earth are contained. 



* See the above-mentioned Essay of M. Stromeyer. 



2 Z 2 Conse- 



