272 FRAGMENTS OF SCIENCE 



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 22d 

 April, 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, 



FIG. 6. Breech-loading Fog-signal Gun, with Bell Mouth, 1 proposed by 

 Major Maitland, R. A., Assistant Superintendent. 



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." * 



1 The carriage of this gun has been modified in construction since this 

 drawing was made. 



8 General Campbell assigns a true cause for this difference. The ring of the 



