544 PHILOSOPHICAL TKANSACTIONS. ■ [aNN0 1774. 



the organs of taste, with its peculiar brisk and acidulous savour, may justly be 

 stiled a mineral elastic spirit of a saline nature, and is sufficiently distinguished 

 from all other saline spirits, by its great rarity, and by its aerial nature. How 

 far, and under what laws, this relation between mephitic air and various saline 

 earths, and other bodies, may be extended, has not yet been fully discovered: 

 suffice it in this place to remark, that a class of saline bodies of a neutral nature 

 are here detected, composed of various earthy bases, united to a volatile aerial 

 spirit, all of which agree in one common solvent, the mephitic air, but differ 

 from each other, according to the nature of the base to which this air is 

 united. 



The agreement of these saline concretes with neutral salts in these essential 

 properties, by which these last are distinguished from other more simple saline 

 bodies, will further appear from their decomposition; which is effected by 

 those various ways, and under the same laws, by which all other neutral salts are 

 decompounded ; namely, by all those different ways, by which the acid spirits, 

 and the terrene or alkaline bases of neutral salts, can be separated from each 

 other. 



For, first, the aerial spirit of these saline concretes, is forced, by fire, from its 

 union with the earthy base, which it holds dissolved in water, in like manner as 

 the acid spirit of other neutral salts are expelled by fire from the more fixed 

 principles, which enter the composition of those salts. The degree of heat 

 required to separate the acid spirit of neutral salts, from their more fixed alkaline 

 or earthy base, varies in the decomposition of almost every different kind of 

 salts; and the extreme volatility and expansive force of this aereo-salLiie prin- 

 ciple renders it more easily separable, by heat, from the fixed principles to which 

 it unites, than any other kind of saline spirit. 



Secondly. The saline concretes, formed with this aerial solvent (in like manner 

 as other neutral salts), are decompounded by the addition of stronger acids, 

 which more powerfully attract the terrene or metallic base of these concretes, 

 than it is attracted by their light and subtle aerial spirit, and detaches from them 

 the aerial solvent to which those earths were before united. All acids, found in 

 a liquid form, have this effect from the light vinous acids to the most ponderous 

 acid of vitriol; so that the affinity between these metalline and absorbent earths, 

 and this their aerial solvent, is less than that which exists between the same 

 earths and all the known acid spirits. In all additions of these acids to the spiri- 

 tuous or acidulous waters, an efitrvescence has been observed, not readily 

 accounted for, by those who suppose an acid to predominate in those waters. 

 The conflict and discharge of air here arises from the expulsion of the aerial 

 principle from its terrene base; in like manner as the acids of sea salt and nitre 

 are expelled, with effervescence, from their alkaline bases, by the more powerful 



