BURSTING OF HEAVY GUNS. 
187 
for if it is shown that the ultimate strength of a coiled inner barrel is 
greater than that of a steel tube, and that such a barrel yields 
gradually, it gives support to Sir W. PallisePs steady advocacy of 
coiled iron. Its bearing upon the cause of the bursting of the 
“ Thunderer 33 gun is less apparent, but we believe that Sir W. Palliser 
would trace the connection in the following way :—He holds that the 
mischievous strain falls on the gun exactly at the seat of the front 
charge of a double-loaded gun, and that a gun burst simply by double 
loading would yield at this place. He admits, of course, that the gun 
recently burst at Woolwich was burst by double loading, but he 
considers that its turret companion gave way at a point further 
forward; consequently I believe that he is not yet satisfied that 
double loading was the real cause of its destruction. The Erith 
experiments, so far as they may be found to localise the exact position 
of the strain, would so, he would consider, bear out his opinion. 
Shortly, then, it would be Sir W. PallisePs wish that the gun to be 
tried should bear a great strain; should ultimately yield gradually, 
giving notice of its yielding; and lastly, should furnish evidence that 
the strain falls chiefly on the precise spot where the front charge is 
situated. 
The gun tried was a 7-in. rifled gun of 95 cwt., converted from a 
10-in. shell-gun of 84 cwt. by means of a coiled wrought-iron barrel. 
The piece was a veteran, the shell or outer casing of it being a 10-in. 
gun which had been fired in the trenches at Sebastopol in 1855. 
I suppose it must have been one of two 10-in. guns mounted rather 
late in the siege, which did good work against the left face of the 
f<r Great Redan.” This gun had been struck and cut by shell in the 
muzzle. Prom a sentimental point of view, it was melancholy to witness 
its vivisection in its old age. 
The strength of the piece, of course, depended on its inner tubes, 
which also had a history. There were three of them, as shown in 
Fig. 1. The outer of the three had been placed originally in a 68-pr. 
gun of 95 cwt., with a steel tube inside it. The steel tube had split in 
firing, and had been bored out, and the second coil had been inserted, 
giving a calibre of 7 ins. The 68-pr. gun thus lined had been severely 
tested in various ways—I might almost say tested to destruction, the 
breech blowing out at the 136th round. The double coil had then 
been removed and entered as a lining to the 10-in. gun employed in 
this trial, the chase being at first bored out to a diameter of 8 ins. and 
rifled. In this condition, weighing in all 4^ tons, it was tested very 
severely at Shoeburyness, in consequence of a gun with a steel lining 
having given way; being not only subjected to the proof-firing of a 
9-ton gun, but shells fired with air-spaces and made to burst in the 
bore. The coils bulged, but did not burst. The gun then went to 
Newcastle, and a new vent was drilled, and it was fired at Ridsdale— 
ten rounds with 30 lbs. of R.L.G. powder and 180-lb. projectiles. 
Next it was bored up to 8Jins., and lined with a third tube 0*75 in. 
thick, bringing the calibre to 7 ins. In this state it was rifled, and 
fired two rounds with 27J lbs. of powder and with a 115-lb. shot. 
This gun, then, has performed very hard service indeed, with the 
