196 FRAGMENTS OF SCIENCE. 
ally upon the best possible shape, arrangements were made 
with the War Office for the construction of a gun specially 
calculated to produce the loudest sound attainable from 
the combustion of 3 Ibs. of powder. To prevent the 
unnecessary landward waste of the sound, the gun was 
furnished with a parabolic muzzle, intended to project 
the sound over the sea, where it was most needed. The 
construction of this gun was based on a searching series 
of experiments executed at Woolwich with small models, 
provided with muzzles of various kinds. A drawing 
of the gun is annexed (p. 197). It was constructed 
on the principle of the revolver, its various chambers 
being loaded and brought in rapid succession into the 
firing position. The performance of the gun proved the 
correctness of the principles on which its construction was 
based. 
An incidental point of some interest was decided by the 
earliest Woolwich experiments. It had been a widely 
spread opinion among artillerists, that a bronze gun pro- 
duces a specially loud report. I doubted from the outset 
whether this would help us; and in a letter dated April 
22d, 1874, I ventured to express myself thus: " The 
report of a gun, as affecting an observer close at hand, is 
made up of two factors the sound due to the shock of the 
air by the violently expanding gas, and the sound derived 
from the vibrations of the gun, which, to some extent, 
rings like a bell. This latter, I apprehend, will disappear 
at considerable distances/' The result of subsequent trial, 
as reported by General Campbell, is, " that the sonorous 
qualities of bronze are greatly superior to those of cast iron 
at short distances, but that the advantage lies with the 
baser metal at long ranges/'* 
Coincident with these trials of guns at Woolwich, gun- 
cotton was thought of as a probably effective sound-produ- 
cer. From the first, indeed, theoretic considerations caused 
me to fix my attention persistently on this substance; for 
the remarkable experiments of Mr. Abel, where by its ra- 
pidity of combustion and violently explosive energy are 
* General Campbell assigns a true cause for this difference. The 
ring of the bronze gun represents so mucb energy withdrawn from 
the explosive force of the gunpowder. Further experiments would, 
however, be needed to place the superiority of the cast-iron gun at a 
distance beyond question. 
