BURSTING OE HEAVY GUNS. 
193 
fore part of the gun, remained on the carriage; the breech portion 
going back against the interior of the turret with sufficient violence to 
indent the inner steel skin and force the backing against the outside 
armour-plates—which are 22 ins. thick—so as to open two of them, to 
a certain extent, “ like a pair of folding doors.” The wrought-iron coils 
built on round the inner tube are said not to be injured themselves, 
but drawn asunder, causing a sufficient escape of gas to burn, knock 
down, and hurt nine men who, were inside the turret. Two only are 
reported seriously injured, being severely -burnedthese two having 
stood close beside the gun, opposite the place where it opened. We 
are informed that the breech of the gun rebounded from the turret 
and came back in contact with the muzzle portion still remaining on 
the carriage. The gun had been loaded by hand with the following 
ammunition:—A battering charge of 551 lbs., of Fossiano progressive 
powder, and a 2000-lb. projectile. The steel tube is said to have 
yielded just at or near the base of the truncated cone leading from the 
enlarged chamber into the bore. 
This, I think, sums up substantially what we are told of the facts of 
the case. Supposing these to be correct, what is to be gathered from 
them ? The following characteristic features should be noticed :— 
(1) The gun yielded in the longitudinal direction; (2) the steel tube 
only is broken; (3) the amount of injury done by the gas is very small 
indeed in proportion to the magnitude of the charge. 
I need scarcely remind you that on firing, the work done on the gun 
in the backward direction is equal to that effected on the projectile 
moving forward, and that the recoil of the gun is checked through the 
medium of the carriage, which is held to the gun by the trunnions. 
Consequently when the gas, acting against the bottom of the bore, is 
driving back the breech, while the trunnions are being held by the 
carriage, a longitudinal strain is brought on to the gun between the 
breech and trunnions, in proportion, on the one hand, to the force of 
the charge, and on the other to the inertia of the front portion, and 
the carriage, and the quantity of friction or hydraulic pressure that is 
brought to bear upon them, in this instance, I believe, through the 
trunnions, in order to check recoil. This strain must always exist. 
What is there to resist it ? In Fig. 1 is shown a section of the gun in 
question/which is, I believe, correct. In looking at this section, it will 
be seen that the longitudinal strength of the gun against extension 
depends almost entirely on the inner steel tube. The outer coils are 
short, and are not hooked on to one another so as to assist in holding 
the gun together longitudinally. Consequently, if the inner tube 
yielded, it is easy to understand how the gun might be pulled asunder. 
We are told that the steel tube parted at the base of the conical portion 
connecting the powder-chamber and bore. If this occurred, the gun 
might come asunder at the line marked at without experiencing much 
resistance beyond “ the friction due to the biting of the front portion 
of the 3 B coil” on the hinder part of “ 2 C coil.” The process of 
yielding would be gradual, depending on the excess of velocity of the 
breech portion over the more slowly recoiling front portion and carriage. 
Ho considerable escape of gas would take place until the front edge of 
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