FORTIFICATION, a term derived through the Italian from the Latin fords and facere, menus literally the "making strong" of any place whatever, be it a town, an arsenal,a camp, a mere house, or the extended position of an army occupying a tract of country, a province, or even a kingdom. In effect, the term is limited to strengthening by means of walls, ditches, or other stationary obstructions, aided more or less by artil lery, which may impede hostile advance.
F. cannot pretend to render strongholds impregnable, for no works, however skill fully devised, will withstand the continued fire of well-directed artillery, backed by energy and discretion on the part of assailants: its aim is to enable a beleaguered garri son to hold out, without losing ground, until it can be relieved by the advance of allies operating in the field. In fortifying a place, the engineer usually proceeds upon some defined system of entourage; but if he hope for success, his science must be sufficiently elastic to adapt itself to all the natural features of the locality; and from this it follows that a system perfect in theory, and of universal application, will in practice have to undergo modifications, differing in almost every instance.
The origin of the art is involved in an obscurity which history need not hope to penetrate. The earliest records of all nations speak of walled cities and forts.
The prime element of all F. is the parapet (from Italian para, before; petto, the breast), which may be a wooden stockade, a wall of masonry, or a mound of earth, and is intended to give more or less cover to the defender from the projectiles of his adver sary, while he is still able to use his own weapons against the latter. The simplest form of parapet being the mound of earth, the ground adjoining it would probably be dug up for its formation, and from this would almost unconsciously ensue the ditch, as an additional means of separating the assailant and the assailed. Starting, then, from this parapet and ditch or fosse, as the elementary forms of defense, it will be well, before proceeding to describe the ancient and modern systems, to give concise practical defini tions of the parts, adjuncts, and technical names of a fortification.
The first duty of a defender is to prevent, as far as possible, the enemy's near approach to any of his works. In developed systems, this is sought to be done by bas tions, etc. (of which hereafter), which stand out at angles to the general line, so as to afford a fire commanding all parts. But as cases occasionally happen of troops, defended by a mere straight parapet and ditch, having to withstand the advance of the enemy, it is necessary to adopt every measure which can obstruct his path, harass his advance, and, if possible, aid in cutting off his retreat in the event of failure.
Abattis (q.v.) are among the simplest obstacles to be improvised, consisting of trees cut down, shorn of their leaves and smaller twigs, having their branches pointed, and then laid close together, in one or more lines parallel to the works, branches outward, and trunks imbedded or pinned down in the earth. Accoutred troops must remove these before they can pass, and the operation of removal under fire from the besieged is a very serious one indeed.
Chevaux-defrise (q.v. for derivation) are pointed iron or wooden rods fixed crosswise in a wooden beam, and until removed offering a complete obstacle to progress. They are very useful in a breach or other unclosed portion of a work, and are now made in pieces, so as to be portable, and yet ready for immediate putting together. A cheval de-frise is usually 12 ft. long, with a beam 9 in. square. • Chansse-trapes, or Caltrops (q.v.), give serious annoyance to troops advancing, and are especially dangerous in cases of night-attack. Their use was, however, more general formerly than it is now.
Trous-de-loup (wolf-traps), which are deep holes dug, and armed at the bottom with spikes, young trees cut down and their stumps pointed, inverted harrows, broken sword blades, bayonets, or any similar annoyances, are resorted to as expedients to gain time, and thereby insure a more deadly fire on the assailants. They are frequently constructed in the glacis of a work.