THE ROYAL ARTILLERY INSTITUTION. 
437 
pressures was, as far as he was able to go, because it takes account only of 
absolute pressure, and not of sudden pressure or wave motion. 
There is a difficulty in applying Bumford's method to an ordinary gun, 
because the recoil of the gun would prevent the arrangement of the heavy 
weight on the top of the stopper; but in a gun with a movable breech this 
difficulty would not occur, because the barrel does not recoil. 
If these two methods of measuring the pressure coincide, as I am con¬ 
fident they must, not only on my own mature consideration, but also because 
they meet the approval of so able and successful an experimenter as 
Mr. Bashforth, the results might be safely relied on, and laws would be 
established which would allow of extension, so as to tell with certainty what 
would be the probable fate of any proposed new gun; and in future we 
should be able to justify our preference for big or small bores, not by the 
opinion of any individual, however eminent, but by the invariable laws of 
science, deduced from experiment. No doubt such experiments would 
require a considerable expenditure of public money, but if we go on with 
big guns, as go on with big guns we must, they will result in a gigantic 
economy; and, if these investigations were combined with what we already 
know, and what yet remains to be determined in the other branches of 
gunnery, our English artillery would, as heretofore, maintain its position as 
the first in the world. 
At the close of the lecture— 
Colonel W. J. Smythe invited gentlemen present to make any remarks they 
thought fit on the subject, or to ask Captain Morgan any questions. 
Captain C. Orde Browne, E.A., Captain Instructor Boyal Laboratory, asked 
for an explanation of the mode in which Captain Morgan proposed to register what 
he understood as local pressure by a movement of the breech. He thought the 
breech would fail to indicate any sudden local pressure, or slight variations in 
pressure, from the momentum it must necessarily possess; and hence in registering 
such pressure he thought there was a great advantage in having something 
stationary, although he admitted the advantage of obtaining a continuous trace of 
a curve over registered points ; but perhaps he had not understood the lecturer. 
Captain Morgan said the local pressure was due to the wave-like motion of the 
gases, and by his plan he thought these waves could be detected, if the breech was 
light enough, as clearly as if they were successive blows. 
Captain Browne expressed a doubt whether any decrease in the pressure could 
be truly ascertained by that means. 
Captain Morgan said a decrease of pressure would give a less increment of 
velocity. The variation in velocity of the recoil of the breech would be more or 
less according as the pressure was greater or smaller. 
Captain W. H. Noble, B.A., asked what Captain Morgan meant by the indica¬ 
tions of the crusher gauge being affected by the vibration of the gun. 
Captain Morgan stated that the explanation was not his, but was Bodman’s. 
Captain Noble did not consider the explanation satisfactory. He could under¬ 
stand the effect of a vibration in the gas, but he could not see how the vibration of 
the metal of the gun could sensibly affect the dimensions of the copper cylinder 
upon which the amount of pressure depended. 
Captain Morgan said the effect upon the crusher did not depend entirely upon 
