THE BOYAL AETILLEBY INSTITUTION. 
471 
notoriously cheaper than any kind of steel, and it has the fortunate 
property of bulging before it bursts; thus giving warning to the gunners 
when a gun is near the end of its existence, whereas steel will up to 
the last round preserve a delusive appearance of unimpaired strength. 
Steel is advocated by Sir J. Whitworth on account of its greater 
tensile strength; but this, its undeniable property, has not yet been 
proved by the infallible test of experience to afford a safe criterion of 
its superiority for artillery purposes. 
There are, indeed, some kinds of strain that wrought-iron is better 
able to withstand than steel; and although it would be premature to 
state positively that the strain on the body of a gun is of such a nature, 
there are nevertheless some grounds for supposing so. 
It has been proved by trial that steel armour-plates are easier of 
penetration than plates of wrought-iron; and, indeed, various combina¬ 
tions of steel with wrought-iron have also been tried, but have all 
proved a complete failure as compared with the simple wrought-iron 
plate. Here, then, is an example of a strain which steel is less capable 
of supporting than wrought-iron, and it is to be observed that the 
strain on a gun is of a like sudden nature. 
But a direct objection to steel is its uncertainty. It is difficult to 
obtain uniformity, either in its quality or its temper, and when manu¬ 
factured there are no means of deciding upon either of these points 
except by the destruction of the gun. 
An example of the difficulty in judging of metal when in a manu¬ 
factured state, is to be found in the case of one of the Whitworth 12-prs. 
tried by the Armstrong-Whitworth Committee. Sir J. Whitworth, in 
his evidence before that Committee, 7th February, 1865—questions 
3724 and 3862—twice stated that these guns were made of “ homo¬ 
geneous metal,” but in one which had been destroyed it was found, by 
subsequent analysis, that the trunnion ring and trunnions were of 
wrought-iron (see question 3860, p. 145), so that he was in fact 
ignorant of the metal of which an outside portion of one of his own 
competitive guns consisted, although made in his own factory. 
Thus it happened that, in his own estimation and in that of the 
Committee, the performance of a piece of wrought-iron was credited to 
“ homogeneous metalnor would the error have been discovered but 
for the destruction of the gun, when the appearance of the fracture 
revealed the fact. 
Of the danger and uncertainty of steel we have ample evidence, both 
in this and other countries, and it must be borne in mind that the 
failure of steel in small guns is an a fortiori argument against its use 
in large guns, and secondly, that these failures have occurred in a com¬ 
paratively insignificant experience of steel ordnance. 
In June, 1860, a puddled-steel 12-pr., made by the Mersey Steel and 
Iron Works, burst at Shoeburyness at the sixth round. 
In June, 1861, a 7-inch steel gun by the same makers burst at the 
sixteenth round j while in November of the same year a 20-pr. Krupp 
gun burst at the second round. 
In March, 1862, a French 30-pr. steel gun burst at Gavres. 
In August, 1865, a Krupp 9 J-inch steel gun burst with a moderate 
