112 AZOTIC GAS. 



atoms of oxygen ; and an atom of azote weighs 

 1-75. 



It appears from an experiment, which I have 

 stated above, that 8-65 grains of saltpetre con- 

 tain 4-004 cubic; inches of azotic gas. Now, as 

 nitre is a compound of 6 potash and 6*75 nitric 

 acid and as nitric acid is a compound of 1*7^ 

 azote and 5 oxygen it is obvious, that 8 '65 

 grains of nitre contain 



Azote 1-187254 gr. or 4*00386 cubic inches, 

 Oxygen 3-392155 - - 10-00960 cubic inches. 



4-579410 



Now, 4-00386 : 10-00960 : : 1 : 2-5. So that the 

 constituents of nitric acid, when converted into 

 gases, consist of 



1 volume azotic gas 

 2^ volumes oxygen gas. 



But we have seen already, that half a volume of 

 oxygen gas is equivalent to an atom. It is ob- 

 vious, that a volume of azotic gas is equivalent 

 to an atom ; in this respect, azotic gas agrees 

 with hydrogen gas, chlorine gas, and the vapour 

 of iodine. 



The specific gravity of azotic gas is obtained 

 by multiplying its atomic weight, 1*75, by 0-5555. 

 The product is 0-9722, which we have found to 

 be the true specific gravity of this gas. 



