234 ON A NATURAL SYSTEM 



to determine from other data, to which they 

 ought in preference to be adjudged. In like 

 manner, aerated and fluorated lime, muriated 

 filver, and fome others are to be conlidercd. 



SLVI. Affinity o 



BY the law of continuity, we may obferve a 

 great aftinity among the feveral dalles of fof- 

 fils. 



LVJI. Affinity of Salts *witb Eartbs and Alf- 

 tah. 



WE have already taken notice of the connex- 

 ion of falts with earths, and we may add further 

 to our remarks on this fubjcdt, that burnt lime, 

 by the intermedium of the matter of heat, ac- 

 quires a folubility perfectly faline. The fame 

 thing happens to ponderous earth, but not to 

 magnefia. In all metals there lurks a certain 

 acid peculiar to each, the nature of which we 

 have as yet explored in ai feme only. Thefe 

 metallic acids diiTer from all others in this re- 

 fpect, that, when taken with proper proportions 

 of phlogifton, they become metallic calces; but 

 iffaturated with that principle they are reduced 

 to a perfect metallic Hate *, generating at the 



fame 



* Effays, vol. 3. p. 124. * 



