Chap. 6.] of Nitrous Air. 



marine acid or fpirit of fait, and cauftic alkali, both ex- 

 tremely corrofive, is formed that innocent and whole- 

 fome fubftance, common fait; and from two fubftances 

 innoxious to the human frame, fulphur and oxygen, 

 vitriolic acid, or fpirit of vitriol, is formed. In com- 

 mon air, azote and oxygen are indeed in a ftate of mix- 

 ture, but they are not combined; for to make them 

 enter into a ftate of combination, the operation of a 

 flrong agent, fuch as fire from the electric fpark, is 

 neceffcry, and without this, azote appears to have little 

 or no attraction for oxygen. In the ordinary procefs 

 of refpiration the mixed fubftances are inhaled; and 

 it is probable that they are foon again feparated in this 

 procefs, and each differently difpofed of. In nitrous 

 gas, the azote and oxygen are in a ftate of chemical 

 combination, and it is a third fubftance different in 

 qualities from both ; it is, indeed, an imperfect nitrous 

 acid in an aerial form ; though azote, therefore, in its 

 fimple uncombined ftate, has no attraction for oxygen, 

 it is different when by combination it becomes an acid ; 

 it has then a ftrong attraction for that fubftance which 

 is ncceflary to give it the true acid character, and it will 

 abforb it till it arrives at what the chemifts call the 

 point of faturation, that is, till it is made a perfect acid - 9 

 and this is the reafon that it fo rapidly attracts and con- 

 denfes the pure air of the atmofphere. 



4th. Nitrous air pofTcjfTes the property of preferving 

 animal fubftances from putrefaction, and of reftoring 

 thofe already .putrid, in a ftill greater degree than 

 fixed air, and on this the antifeptic power of nitre, may, 

 perhaps, chiefly depend. On putting two mice, the 

 one juft killed, the other putrid and foft, into a jar of 

 nitrous air, and letting them continue in it twenty-five 

 days, in the months of July and Auguft, there was little 

 or no change in the quantity of. air; both mice were 



perfectly 



