THE ROYAL ARTILLERY INSTITUTION. 
21.1 
Whether the exact proportionate strength mentioned by the critic 
be correct or not, it is evident that he is right in saying that the 
strength of the inner layers of the bronze steel, taken a per se.,” is 
much less than that of the inner layers of a Krupp gun; a part of the 
work towards the limit of fracture having already been performed 
upon them. Still, if they be much better supported by all the layers 
outside them, they may be quite strong enough for the purpose 
required, as compared with a Krupp gun, the stronger inner tube of 
which may not be so well supported.* 
As to the toughness of the outer strata, not compensating, for the 
small expansion of the inner layers before fracture, and so not ensuring 
safety against explosive rupture under an excessive strain; this seems 
a doubtful point, which can only well be determined by experiment. 
3 .—■“ The elastic tension exerted primarily from without inwards 
against the bursting effect of the powder, is continuous through all 
the strata of the metal. The neutral stratum, where the inward and 
outward pressures are balanced, is situated quite close to the bore. 
“ The elasticity of the whole thickness of the wall must be overcome 
simultaneously as well as lastly, the enormous toughness of the outer 
strata, which may be subjected to an extension of 40°/^ without tearing 
before the gun will burst. 
“ In the ringed steel gun the neutral stratum is situated at the 
contact of the barrel and the rings, and the force of the explosion falls 
almost entirely on the rings. The gun will hold out, provided the 
limit of elasticity of the rings is not exceeded ; but should an excessive 
strain cause one ring to fly, the other parts of the gun will, in all 
probability, follow. - ” 
RemcCrh. —“ The expansion of the individual strata of the barrel, 
arising from the driving through of the cones, seems to correspond to 
the laws of elasticity laid down by Lowe. The ringed steel gun is so 
constructed that the barrel previous to firing is compressed to a certain 
fixed degree, while the rings are in a state of expansion ; thus on firing 
the limits of elasticity in the strata of both barrel and rings are reached 
simultane ously. 
“ Again, since the tenacity of the barrel at the limit of elasticity is 
greater than the force of the powder gas, the rings are virtually less 
affected than the barrel, and not viee versa, as the General would lead 
one to believe.” 
Here the General and his critic seem to agree, save on the question 
as to when and to what extent the strength of the rings of a Krupp 
gun is called upon when the powder-charge is exploded. 
This is a matter of adjustment depending on the limit of elasticity of 
the barrel, that of the successive coils or rings when shrunk on, and on 
the amount of compression given to the inner barrel. No doubt if this 
adjustment is perfect the limits of elasticity of all might be reached 
simultaneously, but then comes the dangerous point in steel. What 
amount of expansion have the outer rings beyond the limit of elasticity? 
for upon this depends greatly the safety against explosive bursting, a 
* Vide Note on previous page* 
28 
