THE ROYAL ARTILLERY INSTITUTION. 121 
the behaviour of the Woolwich gun at Tegel, the steel portions having been 
the parts which have generally and most unexpectedly failed. 1 
Then, again, there is the instructive history of the vent-pieces of the 
Armstrong guns, which were originally made of steel, but which material 
had to be given up for this purpose in the larger guns, in 1862, in conse¬ 
quence of the numerous failures which occurred. Sir William Armstrong 
has said on this subject :■—“ In breech-loading guns, I pertinaciously adhered 
to steel for the screws and for the vent-pieces, until I was completely driven 
away from the material. I could not depend upon it, the material was so 
various in quality; and all subsequent experience has shown that, for those 
purposes, wrought-iron stands incomparably better than steel.” 2 
We have, further, the recent failure of, and absence of uniformity exhibited 
by, the Whitworth steel shell which were fired at Shoeburyness on March 2, 
1870. These shells had all been specially prepared for experiment with great 
care: one was good, one went to pieces on the target, and the third went to 
pieces in the gun. 3 
As an example of the impossibility of inferring from the statical resistance 
of steel, its power to sustain dynamic strains, we have the failures which 
attended the attempt which was made by Sir William Armstrong and others 
to employ steel for armour plates, and which illustrates the unfitness of steel, 
even when of the best and toughest quality, 4 to resist violent shocks or 
concussions. 
The fact is, that between the strains exerted by the ordinary tests and 
those imposed on the material of a gun, there is no analogy. In the former 
case, it is a mere dead quiet pressure put on and relieved; in the gun, it is 
a sudden and violent blow, setting up a violent vibratory action; and 
experience goes to show that steel is much less adapted to resist a strain 
of this kind—however it may behave under a strain of the former kind—- 
than wrought-iron. It is really not so much a question of dead strength or 
ductility, but of fitness for resisting violent concussions. 
It is no answer to these objections to urge that the lack of uniformity in 
steel may be corrected and overcome by careful tempering; for, in fact> 
although the steel may be more or less improved by tempering, its normal 
variableness of nature is not annihilated, or even materially altered, by the 
1 “ All the failures, whatever failures there are, have been, not in the part which has been made 
of coil, but in the part which has been made of steel. All our experience shows that the steel is 
much more liable to fail than the wrought-iron part, and it appears to me that, if yod alter the 
pattern, so as to discard the wrought-iron coil in favour of steel, you are really discarding that part 
which has never failed.As far as my experience goes, I should certainly avoid thes 
use of steel to the very utmost in guns, because I consider it the only part that is not fully to be 
depended upon. I only introduced it originally as material for the bore, on account of its superior 
hardness, but I depend far more upon the strength of the coil than I do upon the strength of the 
steel, as far as the safety of the gun is concerned.”—Sir "William Armstrong’s Evidence before War 
Office Council. 
2 Sir William Armstrong’s Evidence before War Office Council. 
3 It may be well to state that these shells were fired without powder in them, and their failure 
cannot therefore be attributed to the action of the bursting charge. 
4 The steel tried by Sir William Armstrong for this purpose was toughened in oil. It waS 
subjected to the ordinary statical tests, and “ exhibited the most extraordinary strength and ex¬ 
traordinary toughness and ductility, far exceeding that of any specimen of wrought-iron I evei: 
saw.”—Sir William Armstrong’s Evidence. 
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