Ki '-arches refpe&big 



appearance of nitrate : the reudue, treated as in the preceding 

 experiment, gave analogous refults. 



L. A mixture of equal parts of muriate of potafh and ni- 

 trate of lime, afforded, i. Nitrate of potafh, mixed with a 

 little muriate of potafh; 2. Muriate of potafh, which was 

 mixekl with a fmall quantity of nitrate of potafh. The un- 

 ".allizable refiduum was diffolved in alcohol; there was 

 a Reparation of nitrate of potafh, which was fufed upon ig- 

 nited charcoal, but contained a little muriate of potafh, as 

 was U'^n by the left of the folution of nlver. The fulphuric 

 acid fhoweu that the part diffolved by the alcohol contained 

 muriatic acid, nitric acid, and lime. 



In the above experiments, in which fubftances were em- 

 ployed whole combinations could not have a confulerable 

 force of cryftalUzation, and differed but little among each 

 other in this refpecl, it is evident that the formation of the 

 falts obtained by cryftallization depended on the proportions 

 of the fubftances which mutually acted among each other. 

 In experiment I, which might afford nitrate and muriate of 

 potafh, as thefe two falts differed little in their folubility, 

 which, however, is rather the leaft in the latter, the nitrate 

 of potafh was obtained by the firft cryftallization; but as in 

 experiment K the muriatic acid exifted in a greater propor- 

 tion, muriate of potafh only was then obtained; one part of 

 potafh with muriatic acid, nitric acid and lime formed the 

 refiduum. The proportions employed in experiment L dif- 

 fered little from thofe of I, and the refults were nearly the 

 fame. Oppofite combinations, therefore, are obtained ac- 

 cording to the proportions employed, or according to the 

 period of cryftallization ; that is to fay, according to the pro- 

 portions of the fubftances which remain in acTion when a 

 fufficient force of cohefion does not exifl in the combinations 

 that might be formed. But according to the opinion adopted 

 bv chemifts, the entire change of bafe, which it is affirmed 

 muff, take place, may be judged of even by a firft crvftailiza- 

 tion. If, for example, nitrate of potafh be firft obtained from 

 the proportions which have been employed of muriate of 

 potafh and nitrate of lime, a conelufion is made, that an 

 exchanoe of bafe has been effected between the muriatic and 

 nitric acids. If other proportions had been employed which 

 would have afforded muriate of potafii, as in experiment fv, 

 an oppofite confequence would have been drawn. Chemifts 

 have even gone further: from the conclufion refpefting the 

 change of bafe, for example, between the muriatic and nitric 

 acids^ a further inference has- been made, that the combina- 

 tions 



