Chap. 4,] Cboak Damp. ^89 



and its properties may be enumerated in few words, 

 ift. It extinguifhes flame, id. It is fatal to animal 

 life. jd. It is heavier than common air. 4th. From 

 its acid character it refifts putrefaclion. ^th! It ren- 

 ders alkalies, &c. mild. 6th. Water, under the com- 

 mon prefiure of the atmofphere, and at a low tempe- 

 rature, abforbs fomewhat more than its bulk of this 

 gas, and in that ftate conftitutes a weak acid rather 

 agreeable to the tafte, whence fixed air is a conftituent 

 principle in moft mineral waters ; indeed the water of 

 Iprings and rivers is feldom free from it. yth. It is 

 alfo a conftituent principle of all fermented liquors, 



If a lighted wax taper is let down into a bottle filled 

 with fixed air, the flame will be inftantly extinguimed, 

 and an animal inclofed in a veflel which contains it will 

 immediately expire. 



This fixed air will be found to be much heavier than 

 common air ; its fpecific gravity being to that of com- 

 mon air as 151 is to 100. 



From the greater .weight of this gas it always falls 

 to the bottom of the veflel in which it is contained. 

 An animal (as was before obferved) introduced into a 

 ftratum of this air immediately expires; and it is ow- 

 ing to the prefence of this fluid that the Grotto del 

 Cani in Italy is fatal to animals whole organs of refpi- 

 ration are placed below the level of the mouth of that 

 cavern. This gas may be poured out of one veflel 

 into another like water, or may be poured on a can- 

 dle, which it will extinguifh as effectually as that fluid. 

 Among the moft ufeful properties of fixed air, it 

 has been remarked, that water 'impregnated with it 

 becomes a powerful antifeptic. Moft of the famous 

 mineral waters may be imitated by impregnating wa- 

 ter with fixed air, and then adding that quantity of fait 

 or metal, chiefly iron, which thofe mineral waters, by 

 C c 3 analyfis, 



