Inquiry into the Laws of AffinUjl 153 



hotwithftanding the care which had been taken to obtain the utmoft cryftalllzation ; this 

 refidue was formed of nitrates and fulphates ; for it precipitated abundantly with the 

 nitrate of barltes, and after drying it flowed on ignited charcoal. This experiment ought 

 to be compared with experiment F. 



Experiment H. One part of nitrate of pot-afh, and two of fulphate of foda, gave, i. 

 fulphate of pot-a(h ; 2. fulphate of pot-a(h, and fome needles of nitrate of pot-afh ; 3, ful- 

 phate of pot-afli in fmall prlfms, fufpended from a pellicle formed by nitrate of foda, fine 

 cryftals of nitrate of pot-afh and nitrate of foda ; the refidue contained nitrates and fulphates. 



In thefe two experiments, the leaft foluble fait of thofe which were formed, viz. the 

 fulphate of pot-afh, was the firft which cryftallized. When the proportions had been thus 

 changed, the atlion of the nitric acid on the pot-afli refumed its fuperiority, and nitrate 

 of pot-afh was formed, though the liquid flill contained fulphuric acid. 



In the fecond, the more abundant fulphuric acid gave rife to a greater quantity of ful- 

 phate of pot-afh; but after the firfl cryftalllzation, more nitrate of pot-afh was formed, 

 though there would have been a fufficient quantity of fulphuric acid to caufe a complete 

 change of bafe, if this exchange could have been made as has been imagined. The refidue 

 was formed even in experiment G, of fulphate of foda and nitrate of foda ; and probably of 

 a fmall quantity of fait with bafe of pot-afh. 



7. Experiment I. Equal weights of nitrate of pot-afh and muriate of lime were mixed 

 together: by evaporation there were obtained, 1. nitrate of pot-afh ; 2. muriate of pot-afh, 

 in which was found a little nitrate of pot-afh : the refidue gave with the fulphuric acid an 

 abundant precipitate of fulphate of lime, and vapours of muriatic and nitric, acid were 

 difengaged. 



Experiment K. The experiment having been made with two parts of muriate of lime, 

 and one of nitrate of pot-afh, an abundant cryflallization was effefted of muriate of pot- 

 afh with no appearance of nitrate ; the refidue treated as in the preceding experiment, gave 

 analogous refults. 



Experiment L. A mixture was made the reverfe of thofe of the preceding experiments ; 

 it was formed of equal parts of muriate of pot-afh and nitrate of Hme. It afForded, i. 

 nitrate of pot-afh, mixed with a little muriate of pot-afh ; 2. muriate of pot-afli, which 

 was mixed with a fmall quantity of nitrate of pot-afh. The uncryftallizable refiduum was 

 difTolved in alcohol ; there was a feparation of nitrate of pot-afli, which was fufed upon 

 ignited charcoal, but contained a little muriate of pot-afh, as was feen by the teft of the 

 folution of filver. The fulphuric acid fhewed, that the part difTolved by the alcohol con- 

 tained muriatic acid, nitric acid, and lime. 



In the experiments above defcribed, and in which fubflanccs were employed whofe com- 

 binations could not have aconfiderable force of cryflallization, and differed but little among 

 each other in this refpe£l, it is evident, that the formation of the falts which were after- 

 wards obtained by cryftalllzation, depended on the proportions of the fubftances which 

 mutually a£ted among each other. In experiment I, which might afford nitrate and mu- 

 riate of pot-afh ; as thefe two falts differed little in their fohibility, which however is rather 



Vol. v.— July 1801. X the 



