If the French army had been able to move within a perimeter of 60 miles, with a good supply of provisions, it would have reduced three hundred thousand men to inaction; since the Germans, who leave nothing to chance, reckon--and not unreasonably--that on the field it is desirable to be at least two to one. It would seem then that the art of war now-a-days--as far as resistance to an invader is concerned--consists not in endeavouring to defend any extensive lines which may be taken or outflanked, but in establishing a small number of centres of defence, sufficiently remote from each other and connected by a system of railways in the rear; which are capable of holding out long, and which compel the enemy either to divide in order to watch them or to take them, or to expose his flanks to an attack if he leaves them alone, or to see himself cut off from his base of operations if he advances _en masse_ against one of them without covering himself against the others.... But we must confess to a limited confidence in fortifications on this immense scale. It is certain that they are ruinous: it is not certain that they are effective in proportion to the enormous expense they occasion. The men-at-arms of the fifteenth century cased themselves and their horses in iron to resist crossbow bolts, lance-thrusts, and strokes of axe or sword. Fire artillery, which at first aimed at nothing more than substituting powder for the mechanism of engines worked by counterpoise or ropes, and like these discharged only stone balls, becomes improved and uses iron balls and leaden bullets; and instead of being ponderous and fixed as formerly, moves on wheels and is rendered easily manageable, and at the beginning of the sixteenth century places pistols and arquebusses in the hands of foot-soldiers and horsemen. What plan do the men-at-arms adopt? They thicken the plates of their armour and line them so thoroughly that they are no longer fit for a charge. This method lasts about fifty years, until it is perceived that the best way to enable cavalry to face artillery, so as not to be crushed by it, is to allow it to move rapidly. Cannon are made whose balls pierce through and through the wooden planks of a vessel. Immediately these planks are cased with iron. To-day's balls are resisted by the vessel's sides. The plates of iron are doubled ... and forthwith the penetrating force of the projectiles is increased; but those of the next day pierce them. Steel is made to take the place of iron: but after thousands upon thousands have been spent the projectile has always the best of it. But it happens in a naval engagement that an Admiral steams at full speed right athwart an enemy's ship and sinks it! In fact it is by rapidity of movement and facility in manoeuvring that victories at sea are ensured much more than by increased protective plating.