OF FOSSILS. 241 



5 LXVI. A i 'kalis. 



ALKALIS arc diftinguifhed by a burning tafte, 

 by their convcrfion of blue vegetable colours to a 

 green, and by their powerful attraction for acids. 



$ L x v 1 1 . Salts not faturated. 



UNSATU RATED combinations of acids and al- 

 kalis, enter the genus of the prevailing fub- 

 flancc, unlefs any one ihould cluife to refer 

 them rather to the i in period neutral falts ; 

 which might be done not altogether without 

 rcafon, as the moil of them betray an excels of 

 either the one or the other ingredient. 



LXVI u. Whether neutral Salts arc to be refer" 

 red to a dijlincl Genus. 



IT may be qucflioncd whether an acid cxacr- 

 iy faturuted with an alkali iliould conftitutc a dt- 

 ilincl and fcparatc genus? Or ought rather fuch 

 a combination to be ranked under the acid, or 

 the alkaline falls? If there is evidently an ex- 

 cefsof cither of thcfc principles, as in * 75, then, 

 without doubt t it may be properly ailigned to 

 the genus of the exceeding principle ; but, in 

 all perfect neutral falts, the properties of acid 

 and alkali arc blended lo intimately by fa tu ra- 

 tion, that all diiliaclion between them fcems en- 



Q^ tircly 



