THE ROYAL ARTILLERY INSTITUTION. 
139 
account of tlie products of decomposition of gun-cotton, that no nitric 
oxide or higher oxide of nitrogen is eliminated upon the explosion of gun¬ 
cotton under considerable pressure, as in shells. Coupling this fact with the 
invariable production of nitric oxide when gun-cotton is exploded in open air 
or partially confined spaces, there appears to be very strong reason for the belief 
that, just as the reduction of pressure determines a proportionately imperfect 
and complicated transformation of the gun-cotton upon its exposure to heat, 
the results of which are more or less essentially of an intermediate character, 
so, conversely, the greater the pressure, beyond the normal limits, under 
which gun-cotton is exploded—that is to say, the greater the pressure exerted 
by it, or the resistance presented at the first instant of its ignition, the more 
simple are the products of decomposition, and the greater are the physical 
effects attending its explosion, because of the greater energy with which the 
chemical change is effected. 
