C 8 9 ] 



comes nitrous gas; it extinguifhes light and de« 

 ftroys animals, being totally unfit for animal re- 

 fpiration and combuftion. It is not "diffolved 

 in water, nor does it indicate the lead property 

 of an acid : by combination with vital air it af- 

 fords nitric acid, being, itfelf nothing but nitric 

 acid deprived of a part of its oxygen, and confe- 

 quently a compound of azote, or nitrogen and 

 oxygen, containing, however, more azote and lefs 

 oxygen than the nitric acid ; hence are produced 

 the varieties of this gas, according to the different 

 proportions of azote and vital air. In nitrous 

 gas the azote and oxygen are deprived of all that 

 quantity of caloric and light which they poffeiTed 

 in the atmofphere : the oxygen, however, ft ill re- 

 tains enough of both thefe principles to occafion 

 a combuftion, with flame, of feveral combuftible 

 bodies when immerfed in it, as a pyrophorus, or 

 a fmall portion of fulphuret of alkali > the nitrous 

 gas is then gradually diminifhed, and at length pure 

 nitrogen gas remains. In this cafe, the oxygen 

 of the nitrous gas combines with the inflammable 

 body, and thus the nitrogen gas is left in a free 

 ftate ; hence, as has been intimated, it is evident 

 that azote, or nitrogen, conftitutes the bafis of ni- 

 tric acid, which obtains its acid property from its 

 combination with oxygen. The mixture of one 

 part of nitrous gas, and four parts of oxygen gas, 

 produces red vapours ; becaufe the bafes of each 

 gas mutually combine, and form nitrous acid gas; 

 and the fuperabundant caloric efcapes in the 

 ftate of fenfible heat. If this operation be in- 

 ftituted over mercury, the nitric acid recently 

 formed will remain upon its furface, in the form 



N g{ 



