yd Refearches rcfpeBing 



will both act upon the two hafts equally in the ratio of their 

 maftes : if each of the acids were lirtl combined with a bafe, 

 after the mixture of the iolution of the two falts, the fum of 4 

 the reciprocal forces of the acids and the alkalies would be 

 the fame as before; no muriate of potafh or fulphate of lime 

 will be formed, but there will be a combination of potafh, 

 lime, fulphuric acid, and muriatic acid, which will give the 

 fame degree of faturation as before the mixture. Hence it 

 happens, that when two falts, which, by an exchange, ought 

 to produce combinations which would have very different 

 proportion-, are mixed, neither acidity nor alkalinity, which 

 would necefiarilv mow themfelves if an exchange took place, 

 are obferved, as has been very well remarked by Guyton. 



3d, It has been concluded, merely from the reiult of the 

 precipitation and the cryftallifation that has been obferved, 

 that an exchange of bales has taken place ; but this effect has 

 not been afcribed to its real caufe. 



We have fee 11 (Art. V.) that the force, of cohefion deter- 

 mines the feparation which in elective affinities takes place 

 bv precipitation or cryftallifation : it is the fame force alfo 

 which produces the fame effect in complex affinities. When 

 I mix a folution of the fulphate of potafli with that of the 

 muriate of lime, and when the quantity of water is not great, 

 the lime, in the contact in which it finds itfelf with the ful- 

 phuric acid (No. 1.) experiences the efiecl of the force of 

 cohefion in a higher degree than the potafli. It is therefore 

 a new force which is added to thofe which before exifted ; it 

 muft decide the combination of the fulphuric acid with the 

 lime at the time of its precipitation. 



4th, If we take a view of all the known decompofitions 

 which arife from complex affinities, we mall find that the 

 excels of affinity in oppoiing affinities is always afcribed to 

 thofe fubttanccs which have the property of forming a preci- 

 pitate or a fait that may be feparated by cryfiallization ; fo 

 that, from the degree of the fallibility of the falts which can 

 be formed in a liquid, may be predicted the order of the affi- 

 nities of the • ubitances by which Bergman and other emi- 

 nent chemifts would reprefent the forces in the fymbolicai 

 tables: for they always afcribe a fuperiority o£ affinities to 

 the two fubftances which ought to form a combination in- 

 foluble in regard to the quantity of the folvent. 



Lime, ma^nefia, barvtes, and itrontian, form with car- 

 bonic acid an inioluble fait; all the foluble combinations of 

 thefe earths, mixed with alkaline carbonates, produce an ex- 

 change, the reiult of which is the formation and precipitation 

 of carbonates with an earthy bafe. 



Barvtes 



