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( 39 ) we will say, bores up his 110-ton gun to 16 inches, and fires a corresponding projectile with its appropriate energy. We, for extreme safety, have determined on boring up our 110-ton gun to only 12 inches, and have thus rendered ourselves incapable of firing more than a 12-inch projectile, or one that weighs but some 43 per cent, of that of our opponent, and if moving at equal velocities, carries but 43 per cent, of the energy. The two ships engage in a combat, with the result that our ship falls a prey to the superior power of the enemy, leaving us, as our consolation, the knowledge that in the fight the enemy had blown the muzzle off one of his 16-inch guns, while all our four 12-inch remain intact, for the benefit of the enemy, however, who has taken our ship.

Let us, as a résumé, consider what are the requirements which artillery should meet, and what are the difficulties in the way of satisfactorily meeting those requirements. The first requirement is the power to give high velocity, and accurate direction, to a projectile of such form, that it shall be well adapted to penetrate that which it has to pass through, whether air or armour plate; and that as regards material, it should be competent to deal with thick armour, having a hard face, and a tough body. These are the results that should be obtained on firing the gun.

With respect to the gun itself, its weight must be kept down, and as a result, its material must bear, both circumferentially and longitudinally, a pressure per square inch, instantaneously applied, far exceeding any pressure, to which similar material is ever exposed, for any other purpose.

To afford facility for safe loading, and for the insertion of a cartridge larger in diameter than the bore of the gun, it must be breech-loading. The breech arrangements must be such that they make an absolutely gas-tight joint, and such that the joint can be rapidly made, and that after having been subjected to the enormous pressure brought on it by the explosion, it must be capable of being as readily unmade, so that the breech may be opened.