I^Jt Jti.^nky intgjheLaivs of J^iiUjj. 



ftrong A^ip.n. It would tliereforie have precipitated a confiderab'e quantity of nitrat? of 

 pot-afli, if this ciFeft had not been compenfated, or nearly fo by the folubility which it im- 

 parted to that fait ; but if the folution had been evaporated, there would have beet» ex- 

 tra£led by cryftallizati9n much lef? nitrate, pf pot-a,lh than was contained in the liquid, and 

 an uncryftallizable refiduum would have been left Cmilar to that of experiment C. The 

 proof therefore which might be confidered as concluGve for the obje£l propofed, has in- 

 duced an error refpeGln^ the chemical phenomenon. 



Hence it follows, tl^a^ wh.?n the mother waters of the falt'petre works ajre <lecompofed 

 by pot-aili, the nitrate of pot-afli obtained cotififts not only of that which has juft been 

 formedj but alfo that which was rendered uncryftallizable by the falts with an earthy bads. 



5. I made mixtures of cryftallized fulphate of foda and nitrate of lime Here the ful- 

 phate of foda, and the nitrate of foda which might proceed from the operation, differed 

 little in point of folubility, atid had a cryftalUzing power lefs confiderable than the ful- 

 phate and nitrate of pot-afli. 



Experiment E. Equal parts of cryftallized fulphate of foda and nitrate of lime, reduced 

 tp the ftate of drynefs, gave by evaporation only a fmall quantity of nitrate of fipda. Th? 

 -■uncryftallizable reGdue, which was abuiid^nt, did not precipitate with the muriate of barites, 

 but with the oxalic acid. 



jExperiment K Two parts of fulphate of foda, and one part of nitrate of lime, afforded 

 after evaporation, a greater quaotity of nitrate of foda than the preceding experiment; 

 the uncryftallizable refidue did not precipitate with the oxalic acid, but with the muriate of 

 barites. In order to compare the two laft experiments with the experiments A, B and Cj 

 it muft.be obferved, that the cryftallized fulpLitc of foda contains more than half its weight 

 of water of cryftallization. 



Even in experiment F no fulphate of foda is formed, as fulphate of pot-afh was formed 

 in experiments A and B, becaufe the fulphate of pot-afh has a force of cryftallization much 

 greater than the fulphate of foda. 



The re£due of experiment E did not contain fuch a quantity of fulphurlc acid as could 

 be rendered perceptible by the muriate of barites ; but it was formed of nitrate of foda and 

 nitrate of lime, which probably, by their mutual adtion, fo much exhaufted their diffolven^ 

 power, as.nqt to prevent the feparation of the fulphate of lime No. 3. 



In experiment F the refidue was not precipitated by the oxalic acid, but by the mu-, 

 •riate of barites i fo that this refiduum wascompofed of fulphate of foda, and a greater 

 proportion of nitrate of foda, whiph muttjally prevqiited their cryftallization, as in expft- 

 riment D.. 



6. Experiment G. Equal parts of nitrate of pot-afh and fulphate of foda, gave by fuc- 

 «effivc cryftallizations, i. fulphate of potrafh, and fome fmall cryftals of nitrate of pot-afli ; 

 2. a little fulphate of pot-afli, and a greater proportion of nitrate of pot-afh ; 3. fmall crjf», 

 Aalsoi nitrate of ppt-alb, and much nitrate; of fod^f tl)?re was an uncryftallizable refidue, 



notwithftanding 

 3 



