IS Prof. H. Rose on the Inorganic Constituents 



of baryta is then left undissolved, and its weight must be de- 

 termined after it has been washed. We thus estimate the 

 amount of sulphuric acid. The muriatic solution of the 

 barytic salt is treated with sulphuric acid, and the precipitated 

 sulphate of baryta separated by filtration. It is then super- 

 saturated with ammonia and muriate of ammonia, and sul- 

 phate of magnesia added to precipitate the phosphoric acid. 

 Its weight is calculated from the phosphate of magnesia, after 

 having been heated to redness. 



The liquid from which the insoluble barytic salts have been 

 separated by chloride of barium, still remains to be examined. 

 The excess of chloride of barium is decomposed by carbonate 

 of ammonia. If the liquid is very dilute, it must be previously 

 concentrated by evaporation. The carbonate of baryta is 

 separated by filtration, the filtered liquid evaporated to dry- 

 ness, and the dry residue carefully heated to redness to expel 

 the ammoniacal salts. The remaining mass consists entirely of 

 alkaline chlorides. These are separated in the ordinary way 

 by chloride of platinum. The amount of potash is determined 

 from the weight of the ammonio-chloride of platinum. The 

 amount of chloride of sodium may be calculated from the loss; 

 but it is better to determine it directly as sulphate of soda. 



Part II. — This part of the investigation is commenced by 

 boiling the carbonized mass, which has been exhausted by 

 water, with muriatic acid for a long time ; it is then filtered and 

 washed with hot water, to which a little muriatic acid has been 

 added, until a few drops of the water used in washing leave no 

 residue when evaporated upon platinum foil. Thefiltered liquid 

 is evaporated nearly to dryness in a platinum capsule. The 

 weight of the dry residue cannot be determined, on account 

 of the readiness with which the chlorides of iron and magne- 

 sium are decomposed by heat. The alkalies usually existed 

 in the dry residue as chlorides, whilst they were contained in 

 the exhausted carbonized mass in the form of phosphates; for 

 when the carbonized mass has been washed with water, and a 

 portion of the latter is treated with nitric acid, no precipitate 

 is produced in this solution by solution of nitrate of silver. In 

 arranging the constituents of the muriatic solution, their sum 

 must be taken, and the alkalies represented in the state of 

 oxides. 



I was at first much astonished at finding alkalies present in 

 the muriatic solution, as I had no reason to believe they existed 

 in it. Subsecjuent investigations, however, which I shall de- 

 scribe in a future paper, have shown that when pyrophosphate 

 of lime and pyrophosphate of magnesia are heatetl with not too 

 large a proportion of alkaline carbonates, remarkable double 



