203 Refe arches ref peeling 



Chimie, torn. xi. xiii. xv. xxiii.) It was becaufe, in the ex- 

 periments that were made, a folution of nitrate of potafh was 

 put to digeft upon dried nitrate of lime. The latter neceffa- 

 rily caufed a di vifionof the water, upon which it has a ftrong 

 action . It would therefore have precipitated a confiderable 

 quantity of nitrate of potafh, if this effect had not been com- 

 penfated, or nearly fo, by the folubility which it imparted to 

 that fait ; but if the folution had been evaporated, there would 

 have been icparated by cryftallization much lefs nitrate of 

 potafh than was contained in the liquid, and an uncryftal- 

 lizable reuduum would have been left, : fimilar to that of ex- 

 periment C The proof, therefore, which was confidered as 

 conclufive, induced an error refpecting the chemical phae- 

 nomenon. Hence it follows, that when the mother waters 

 of the faltpetre works are decompofed by potafh, the nitrate 

 of potafh obtained confifts not only of that which has juft 

 been fo med, but alfo of that which was rendered uncryftal- 

 lizable by the falts with an earthy bafis. 



5. I made mixtures of cryftallized fulphate of foda and 

 nitrnte of lime. Here the fulphate of foda, and the nitrate 

 of foda which mig* t proceed from the operation, differed 

 little in point of folubility, and had a cryftallizing power lefs 

 confiderable than the fulphate and nitrate of potafh. 



E. Equal parts of cryftallized fulphate of foda and of dry 

 nitrate of lime gave by evaporation only a fmall quantity 

 of nitrate of foda. The uncryftallizable refidue, which was 

 abundant, did not precipjtate with muriate of barytes, but 

 did with oxalic acid. 



F. Two parts of fulphate of foda, and one part of nitrate 

 of lime, afforded, after evaporation, a greater quantity of ni- 

 trate of foda than the preceding experiment : the uncryftal- 

 lizable refidue did not precipitate with oxalic acid, but did 

 with muriate of barytes. To compare the two laft with the 

 experiments A, B, and C, it muft be obferved that the cry- 

 ftallized fulphate of foda contains more than half its weight 

 of water of cryftallization. Even fulphate of foda was not 

 formed in experiment F, as fulphate of potafh was in expe- 

 riments A and B, becaufe fulphate of potafli has a force of 

 cryftalliztion much greater than fulphate of foda. 



The refidue of experiment E did not contain a quantity of 

 fulphuric acid perceptible by the muriate of barytes; but 

 was formed of nitrate of foda and nitrate of lime, which pro- 

 bably, by their mutual aclion, l'p much exhaufted their dif- 

 folvent power as not to prevent the feparation of the ful- 

 phate of lime No. 3. 



In experiment F the refidue was not precipitated by oxalic 



acid, 



