174 Analysis of several Varieties of 



ceased to have any action. The weight of the insoluble 

 portion was then ascertained* 



(C. a.) By this operation were, dissolved, not only the 

 muriate of soda, but all the other salts, insoluble in alco- 

 hol, which might he mingled with it. To the solution, 

 carbonate of soda was added; and the liquid, which in 

 most cases gave, on this addition, an abundant precipitate, 

 was boiled briskly for several minutes, in order that none 

 of the earthy carbonates, which were separated, might re- 

 main dissolved by an excess of carbonic acid. 



(C. b.) The precipitated earths were allowed to subside, 

 and were well edulcorated with boiling water, the washing 

 being added to the liquor first decanted from the precipitate. 

 To these united liquids (after the addition of more mu- 

 riatic acid than was required for saturation) muriate of 

 barytes was added, till it ceased to occasion any further 

 precipitate. The sulphate of barytes was then washed suf- 

 ficiently; dried; ignited; and its amount ascertained. 



To the earthy carbonates, an excess of sulphuric acid was 

 added in a platina dish, and the mixture was triturated, till 

 all effervescence ceased. It was then evaporated to dryness, 

 calcined in a low red heat, and the weight of the earthy 

 sulphates was ascertained. 



(D.a.) The dry sulphates were washed with a small 

 quantity of lukewarm water. In several instances, the loss 

 of weight, thus sustained, was extremely trifling, nothing 

 being dissolved but a very minute portion of sulphate of 

 lime, of which earthy salt, solely, the residue was presumed 

 to be composed. 



(D. b.) But in other cases, a considerable loss of weight 

 ensued ; and in these, to the watery solution was added a 

 mixture of equal parts of saturated solutions of carbonate 

 of ammonia, and phosphate of soda. A precipitate more 

 or less copious was produced, which was collected, dried at 

 90° Fahrenheit, and weighed. 



(D. c.) By direct experiments I had determined, that 90 

 grains of this precipitate result from the decomposition of 

 100 grains of sulphate of magnesia, of such a degree of 

 dryness, as to lose 44 grains out of 100, by exposure to a 

 low red heat. Hence 100 grains of ammoniaco-magnesian 

 phosphate indicate 111 grains of crystallized, on 62*2 of 

 desiccated, sulphate of magnesia*. From the weight of 



the 



* The assumption that crystallized sulphate of magnesia contains only 44 



Fer cent, of water, though it was correctly true with the specimen on which 

 operated, is below the average, which, I find from several experiments, is 



about 



