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MINUTES OF PROCEEDINGS OF 
gun, on account of the greater weight of shot in proportion to the area 
acted on, and also the reduced windage. In fact the rush of gas over 
the shot may be said to approximate somewhat to the conditions of a 
blow-pipe flame, a large quantity of heat being concentrated on a small 
surface. 
It can therefore be readily imagined that spots of such a fusible 
metal as tin will be at once eaten away when separated from the 
copper; this occurs even at proof, and holes are developed which 
rapidly increase with repeated firing and render the gun unserviceable. 
Out of the three guns used in the late trial at Aldershot two have been 
condemned from this cause, having only fired 242 rounds each, while 
another bronze gun has become unserviceable at Shoeburyness from a 
like reason, having fired about 700 rounds. I have g’utta-percha im¬ 
pressions of these guns on the table and also those of iron and steel 
guns which have fired various numbers of rounds with which to com¬ 
pare them. 
There can be no doubt then that steel is superior to bronze in 
hardness and soundness, and the advantages of these qualities for 
the inner barrel of a gun are obvious. We are not driven to 
resort to “an artifice” so as to “isolate” the cast-iron of the 
projectile from the bore, and we are not limited as regards the hard¬ 
ness of the studs ; in fact ribbed shells can be fired without material 
injury, such shells being stronger, less liable to injury, and, I believe, 
more economical and simpler to manufacture than those having soft 
studs. Moreover double shell can be fired without any danger of 
injuring the gun, and the case shot is not so liable to damage the bore 
and grooves. 
Again the soundness of the material, offering as it does no cavity or 
defect upon which the powder gas can lay hold, causes the erosion to 
be more uniform and gradual, while the higher melting point of the 
material has probably a tendency in the same direction. 
But there is a third point in which steel is superior to bronze for the 
barrel of a gun, viz., in its greater power to resist expansion. In our 
service iron guns the weight of shot and charge of powder are only limited 
by their capability of consuming the powder effectively. But in guns 
made of a soft metal, like bronze, the expansion of the bore at the seat 
of the shot is so considerable that, however secure from bursting the 
gun may be, the charge (including shot) must be restricted within com¬ 
paratively narrow limits, otherwise the efficiency of the gun becomes 
rapidly reduced by loss of velocity, and there is a tendency for the studs 
to override the grooves. The bronze gun referred to before which 
became unserviceable after about 700 rounds, had actually lost 100 ft. 
velocity in that number of rounds, fired with 91b. projectiles only, 
while the iron gun of the same weight was designed for, and is capable 
of, firing a 121b. projectile with a sufficient charge to give it an 
efficient velocity, and such a gun has actually fired nearly 3000 rounds, 
with a comparatively small loss of velocity, in the Armstrong and 
Whitworth experiments. 
There are several other instances of the failure of bronze guns on 
account of the softness and expansibility of that material. In 1867 a 
