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guifhed by the names of oxygen gas, or the pure 

 part of the atmofphere, firft difcovered by Dr. 

 Priettley in the year 1774, and by him called de- 

 phlogiflicated air; by others vital air, becaufe it 

 is the only air that is capable of fuftaining the 

 vital principle, or of fupporting the combuftion 

 of inflammable matter: it is not only the.fole vi- 

 vifying power, but the parent of acidity, and 

 hence named oxygen ff), from the molt general 

 property which its bale poffelTes of forming acids, 

 by combining with different fubftances. 



The other, or noxious portion of the atmo- 

 fphere, is termed azote fg) } from its known quality 

 of killing animals; hence the noxious part of the 

 atmofpheric air, which is totally unfit for refpira- 

 tion, is called azotic gas, or phlagifticated air. 



The atmofphere contains other elaftic fluids 

 analogous to common air, with refpeft to elafticity 

 and invifibility ; but otherwife effentially diffe- 

 rent from each other; fuch as fixed air, or car- 

 bonic acid gas ; inflammable air, or hydrogen 

 gas ; nitrous gas : befides a variety of other fub- 

 ftances, refulting from various exhalations con- 

 ftantly emitted from vegetable, animal, and foM 

 bodies fh); but it is to the gafes above enumerated 

 that the following obfervations will be confined. 



Atmospherical 



(f) Oxygen, oijvr, acidum, or acid, and y^xt, gignor, ta 

 produce, or generate acids, 



(g) Azotum, ct^wrov, from a privation of, and ^m, life. 



(h) Fluoric acid gas t which is difengaged from native fluate of 

 lime, or vitreous fpar, by fulphuric, acid. Muriatic acid gas, or 

 muriatic acid purified from water, and melted by caloric into an 



elaftic 



