SYSTEMATIC FORTIFICATION FOR PERMANENT WORKS.—Adverting to the most ancient fortifications mentioned in history, we find Greek cities surrounded with walls of brick and rubble, and occasionally of stone in huge blocks. Babylon had a wall of prodigious circuit-100 ft. high, 32 ft. thick, and surmounted by towers. Jeru salem, at the time of Vespasian's siege, had similar walls with masonry of enormous solidity. These seem to represent F. as it stood from the time of that emperor to the introduction of cannon for breaching purposes. Then the square and round towers, which had formed sufficient flanking defense against arrows, proved useless when can non-balls, fired from a distance, were the instruments of assault. At the same time, the walls, which had resisted battering-rams, crumbled to atoms under the strokes of artillery.
Fortunately, however, the art of defense has always made equal progress with that of attack; and, early in the 15th, if not late in the 14th c., the Italians had commenced to flank their walls with small bastions. The bastions at Verona, built by in 1523, are usually looked upon as the oldest extant specimen of modern fortification. Tartaglia and Albert Diirer, painter and engineer, were early in the field. In most of the early systems the face of the bastion was perpendicular to its flank. The first principles were successively improved by Marchi, an Italian, who died 1599, by Errard Bois-le-Due, and De Ville, under Henry IV. and Louis XIII. of France. The count de Pagan, whose treatise appeared in 1645, did much towards demolishing previous errors, and laid the basement of that science which Vauban subsequently wrought almost to perfection. Born in 1643, Vauban had a genius which penetrated in every direction, equally in the ways of war and in those of peace. He might possibly have taught how fortresses could be rendered impregnable, had not the restless ambition of his master, Louis XIV., led him to demonstrate, first, that the reduction of any work was a mere question of time and powder. His talent so improved the system of attack, that even he himself could not construct a rampart that should withstand the fire conjured up against it by his discoveries. He constructed 33 new fortresses, improved above 100,
and conducted personally more than 50 sieges. To him are soldiers indebted for the sweeping fire of ricochet, and to him in a degree for the traverses which endeavor to render it harmless. Coehoorn, director-general of the fortresses of the United Provinces, was the contemporary, rival, and opponent of Vauban; his masterpiece is Bergen-op Zoom. Cormontaigne, Belidor, Montalembert, Bousmard, and Carnot may also be men tioned as conspicuous masters in the science.
Irrespective of irregularities in the form of the place to be defended, a particular polygon is selected as that on which the lines of defense are to be drawn. Each side of this is a face of defense, and the length of a side is rarely made greater than 360 yards.
Vauban's second and third systems were those in which he adapted old walls to his modern improvements. Availing himself of the works already formed, he added counterguards in front of the corner-towers, thereby making hollow bastions, and avoid ing the necessity of entirely rebuilding.
Coehoorn's system had counterguards in front of the bastions and parallel to them. The flanked angle of his ravelin had a fixed value—viz., 70°.
Cormontaign widened the gorge of his ravelin, thereby reducing the length of the bastion face available for breaching from without. He also revived the step-like for mation of the covered way, originally seen in Speckle in the 16th c., and which gives defenders a continued line of fire from each traverse along the covered way.
the modern system differs but little from that of Cormontaigne. The re-entering places of arms have circular fronts instead of angular; the angle of the ravelin is fixed at 60°. and all the best points of older styles are associated.
The elements of fortifying against shipping will he found under MARINE FORTIFI CATION; the principles of attacking fortresses generally, under SIEGE, and MnEs MILI TARY.