C 45 ] 



CLASS I. 

 ACID AND NEUTRAL SALTS. 



i. FIXED AIR. ] 



Synonymous Names. 

 Carbonic acid. 

 Carbonaceous acid. 

 Cretaceous acid. 

 Mephitic acid. 

 Aerial acid. 

 Atmofpheric acid. 

 Spiritus fylveftris. 

 Gas fylveftre, &c. &x. 

 Gas. 



This fubftance is found in every part of na- 

 ture that we are acquainted with, in its different 

 ftates ; fixed as it has been called, and aeriform. 

 In our atmofphere it is found in the proportion 

 of aboutonein 100. Pits and cavities are frequent- 

 ly filled with it. It exifts in immenfe quantities 

 combinedwithcalcareousearth,formingchalk and 

 marble ; and with many other fubftances. It is 

 conftantly thrown out from animals and vegeta- 

 bles ; it is the great product of combuftion, and 

 formed in fhort by every procefs, in which pure 

 air is combined with carbonaceous matter; hence 

 it is no wonder that it is fo general and fo fre- 

 quently found the uniting medium to fubftances 

 contained in mineral waters. Mineral waters, 

 which contain this alone, or confiderably prevail- 

 ingjiave been called Acidulae; and perhaps hence 

 all mineral waters were formerly termed Aci- 

 dulae. 



a. Fixed 



