128 Capt. Noble. Preliminary Note on the [June 16, 



Comparison of Pressures in Closed Vessel with those in 47-inch 



Q.F. Gun. 



It must be understood that the differences existing between the 

 close-vessel pressures and the pressures observed in the bore at the 

 higher gravimetric densities are, in great measure, due to the explo- 

 sive at these densities not being fully consumed. An examination of 

 the results obtained would lead to the conclusion that with the 

 particular size of cordite employed tolerably complete combustion 

 cannot be assumed to have taken place until the projectile has 

 travelled some 6 or 7 feet through the bore. Indeed, if the size of 

 cordite fired in this gun be even slightly increased, a portion of the 

 cordite is blown from the muzzle unburned, and it is one of the most 



* ' Phil. Trans.,' Part I, 1875, p. 129. 



