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 manœuvring that victories at sea are ensured much more than by increased protective plating.
And in the art of fortification we are exactly at the same point as were the men-at-arms of the end of the fifteenth century, who heaped plates on plates to protect themselves from artillery. It is time the art of fortification should be modified.
It will be objected that a vessel or a horseman can move about, but that a fortress is immovable, and that consequently passive force cannot here be replaced by active force or agility. This is a mistake. Though a fortress cannot be moved, the defensive system of a district can and ought to be studied, in view of various contingencies. In future warfare the plan of temporary fortification ought to play a principal part and may be made to do so. In other terms, an army ought to be able to fortify itself everywhere, and take advantage of every position. It is temporary fortification therefore which it is desirable to render easy, prompt, and efficacious, in order to defeat the combinations studied beforehand by the enemy, to reduce him in certain cases to the defensive, when he was hoping to attack, and to embarrass his movements on the great scale by unforeseen resistance at a point which he expected to pass with ease, and oblige him incessantly to modify his plans by rapidly executed arrangements for defence.
Vauban's fortresses have had their day; who can conjecture what may be accomplished in a future war by the system of defence of which an example has just been presented?
Still the most reliable fortress for a country is a good and well-commanded army, and a well-educated, brave, and intelligent population, resolved to make every sacrifice rather than undergo the humiliation of a foreign occupation.
Captain Jean's papers contained many other critical remarks which cannot be recorded here. These documents sufficiently indicate that, whatever may have been said about the matter, there were among our officers some who worked, and many who had anticipated the dangers to which we were exposed by a blind confidence in our valour and an utter ignorance of the progress made by our enemies. Indeed among these papers of Captain Jean's, numerous notes, dated 1866, 1867, 1868, show the inefficiency of the defensive system then recognised in France, and the necessity of providing our strong places with works adapted to the recent progress in artillery.
Will the town of La Roche-Pont witness the realisation of Captain Jean's projects, or is its military history closed for ever? The future will show.
In the meantime it is engaged in cultivating its vineyards, and its suburbs are invading once more the slopes of the plateau on the south and the west. The lower part of its donjon of the 12th century is still visible above the escarpment of the little citadel, and antiquaries can discover Roman basements at some points in its wall. When cellars are excavated, Gallo-Roman coins are sometimes found with broken pieces of red and black pottery, charred wood, and even flint hatchets.