108 AZOTIC GAS. 



posed of 5 oxygen and 1-75 azote ; consequent- 

 ly, 29^ cubic inches, weighing 10 grains, is the 

 fifth part of the whole oxygen in 127J grains of 

 nitre. This makes the whole oxygen in 127J 

 grains of nitre to amount to 147*5 cubic inches, 

 or 50 grains. 



But though I have made many attempts to 

 obtain the whole oxygen and azote in a given 

 weight of nitre, in the gaseous state, I have only 

 met with partial success. 



I never succeeded in decomposing nitre in a 

 porcelain retort, without destroying the vessel 

 before the decomposition was completed. The 

 potash, as it is evolved, acts so powerfully upon 

 the vessel, at the high temperature which must 

 be kept up, that it soon makes its way through 

 it, and enables the gaseous products to escape. 



When the nitre was mixed with twice its 

 weight of siliceous sand, I decomposed it with 

 facility in a common stone-ware retort ; but the 

 retort, in the high temperature to which it was 

 necessary to raise it, was pervious to the air. 

 This prevented me from determining with preci- 

 sion the proportion between the volumes of the 

 two gases evolved and Wedgewood retorts, 

 though air tight, always cracked before the pro- 

 cess was completed. In general, the gaseous 

 products consisted of 



1 volume azotic gas 

 2-3 volumes oxygen gas 



