[ 86 j 



eareous earth or lime, to which it has a greater 

 affinity than to any other; it conftitutes nearly 

 half the weight of chalk, limeftone, or carbonate of 

 lime, &c. converting them into faline fubftances, 

 or carbonates; it is produced by burning lime- 

 ftone, in which the carbonic acid combines with 

 caloric, and flies off in the form of gas, leaving 

 the calcareous earth pure, or in a Hate of quick- 

 lime; it is produced plentifully by fermenting 

 liquors, and is often found in coal mines, called 

 the chalk, or chalk damp : it is formed in ca- 

 verns, as in the Grotto del Cano, which extin- 

 guifhes flame and deftroys life. Charcoal, on 

 burning, unites with the oxygen of the atmo- 

 fphere, and forms carbonic acid, which is alfo 

 deftruelive to life, and extinguifhes the light of a 

 candle. 



Water abforbs more than its bulk of this gas, 

 and acquires an acid tafte and .fparkling appear- 

 ance, and mod mineral waters owe their fparkling 

 fpirituous tafte to this gas; and cyder, beer, and 

 other fermented liquors owe their brightnefs to 

 the carbonic acid which they contain. Water 

 4hus impregnated is capable of diffolving a fmall 

 quantity of iron, forming a chalybeate water 

 like Spa, or Pyrmont. When fixed alkali is pre- 

 vioufly diffolved in water, it will then abforb a 

 greater quantity of carbonic acid than common 

 water, and forms the aqua mephitica alcalina. 

 Limeftone, or carbonat of lime, cannot be dif- 

 folved but in a very fmall quantity in water; but 

 pure, or quicklime, can be diffolved in a eonfi- 

 derably greater proportion, forming lime-water, 

 which is a teft of carbonic acid; for it is certainly 



precipitated 



