240 SALTS 



140, by means of which I determined the volume 

 of carbonic acid gas disengaged from a given 

 weight of calcareous spar. A spirit lamp was 

 applied to the bottom of the retort, by which the 

 salt was melted and decomposed into protoxide 

 of azote and water. The volume of deutoxide 

 of azote evolved was measured ; the undecom- 

 posed salt was washed out of the retort, and eva- 

 porated in the very same temperature as the 

 original salt had been till it ceased to lose 

 weight it was then weighed. By this means 



1 ascertained the exact quantity of salt decom- 

 posed. The reader is probably aware, that 

 when nitrate of ammonia is heated it is com- 

 pletely decomposed into protoxide of azote and 

 water, as was shown many years ago by Sir H. 

 Davy. It is easy to see that this must be the 

 case. 



OXYGEN. AZOTE. HYDROGEN. 



Nitric acid composed of 5 atoms + I atom + atom 

 Ammonia . +1 +3 



Total 5 + 2 + 3 



Now, 



3 atoms water consist of 3 +0 +3 



2 atoms protoxide of azote 2 + 2 +0 



Total 5 + 2 + 3 



So that an integrant particle of nitrate of ammo- 

 nia (supposing it anhydrous) is decomposed by 



16 



