Page:Encyclopædia Britannica, Ninth Edition, v. 9.djvu/457

 FORTIFICATION 443 able suggestion from unmerited neglect, and rendered an important service to science by directing the attention of military men to means likely to create a barrier against the growing powers of the attack. The Traite de Fortification tiouterraine, suivi de quatre Jfemoires sur les Mines, by M. Mouze, lieutenant-colonel of engineers in the French service, published at Paris in 1804, is the most complete work on the subject of which it treats which has yet been given to the public. Subter ranean Fortification is a branch of the art which, until recently, was wholly neglected in England, and in which British engineers were far behind their brethren of the Continent. We learn from Colonel Jones s work on the Peninsular sieges that the duke of Wellington s army in Spain was without a trained sapper or miner until late in the year 1813. In this respect things are now changed, and in the Engineers the army has the assistance of a body of men well instructed in the duties of the trench, the sap, and the mine, though it cannot be said even now that the corps of Engineers is of sufficient strength. Nor can this corps, as some contend, be supplemented by civil labour in time of war. Discipline is the foundation upon which the whole military system rests, and the highest skill, unless strictly subordinated to it, will avail little in war. The undisciplined labourer, who, under ordinary circum stances would have worked with the greatest effort, would be found worse than useless if forced to work on his knees in a sap, exposed to an enemy s fire, or upon his back in a countermine, with the knowledge that the enemy s miner, though he cannot fix his precise position, is probably within striking distance. Before going further it is desirable to reciir to the earlier methods, and to investigate the manner in which the ancient arrangement of a wall, with round or square towers, passed into the present systems of defence. Fig. 62 will explain the natural and probable manner in which FIG. 62. Illustrating the Growth of the Bastion. the old tower or rather tower-fort (baluardo] grew into the pentagonal bastion. If, for example, lines of defence be drawn from the extremes of two adjacent curtains to the angles a and c of the square tower-fort A, a space would be left, cla, unseen from the adjacent forts B and C, and therefore undefended, except by downward or vertical fire from machicoulis, or projections from the walls supported by corbels made for the purpose. Such a space would be turned to account by the besiegers in fixing their scaling ladders ; and the change of the straight line ac into the two faces cb, ab seems but the result of a self-evident necessity. As the work became enlarged, the portions of the fort within the connecting walls m, m were omitted, and the flanks dc, fa alone remained of the old wall, form ing with the faces the bastion fabcd, which only required to be improved in proportions to become the bastion of modern times. It is, however, said that the towers were sometimes placed with an angle salient as in B, and if so, omitting the portions mi, the resulting bastion has a strong analogy to those of Errard before mentioned. By using the old wall merely as a retaining wall, and as an obstacle against escalade, and adding to it a rampart and a parapet of earth, the Italians completed the system of bastioned defence, which, notwithstanding all the modifications of the French, ought to be called the Italian system. In this system, whilst imitating the construction of the old towers by using casemated or masonry-vaulted chambers for artillery, in addition to the guns mounted on the ram part, the Italians placed the musketeers on the banquette of the parapet, and made them fire over it. Now this ar rangement of the musketry fire is an essential characteristic of the Italian system, and the reliefs of the several works are by it restricted within certain limits, as it is necessary so to determine the levels of the opposite Hanks that the fire along their superior slopes shall defend the whole of the intervening curtain: but there are other modes of using musketry as well as artillery fire in the defence of the ditches, and on these were founded other systems of Forti fication. The first Italian writer on Fortification was Turtaglia, whose work was published in 1546 ; but the really first writer on the science was Albrecht Diirer, a great painter, sculptor, and engraver, and a civil and military architect, whose work is dated 1527, being published one year before his death. This remarkable man founded his system on the old circular tower-forts C, fig. 62, with which the dead space is much less than with square tower forts, and, enlarg ing the towers to an enormous extent, he adopted the name &quot; Bastei,&quot; or in the plural &quot; Basteien,&quot; for his new work. As attention was at this early period more directed to cannon than to the rude musket as an instrument of de fence, it was natural that the latter should be less con sidered in these arrangements than the former. Diirer based his systems on the principle that the defences of basteien or other works which depend only on the cannon placed on their terrepleines may be effective whilst the enemy is at a distance, but cannot be so when, under cover of his epaulements, he has reached the ditch; and leaving therefore to the cannon on the terrepleine the task of firing upon the enemy s troops and batteries at a dis tance, he placed cannon and musketry either in vaulted galleries running along the base of the escarp, or in caponnieres, also vaulted or casemated works, built across or trans verscly to the ditch. The great circular baste i of his third and most improved system was no less than 130 yards in diameter, with an escarp 120 feet high, a ditch in front 100 feet wide, and a massive envelope, about 80 feet thick and 100 feet high, formed of earth with thick masonry revetements both in front and in rear, as a mask between the main work and the counterscarp. Such gigantic proportions as these have led many to con sider Diirer as little more than a speculative writer, but this would be an unjust estimate of his real merits. Ileducing his works to more reasonable dimensions, they would, with proper modifications, have become practicable, and they Lave afforded many useful hints to the scientific engineer. The defects of the circular form were compensated by the grazing fire of the caponnieres in his system, and the main work was retained in an effective state by the cover afforded to it by the envelope. We shall have occasion to refer again to Diirer, but in the meantime it may be said that whilst the Italians are properly considered the originators of bastioned systems with an earthen parapet over which the musketry fire is directed, Diirer has an undoubted claim to be considered the author of the sj^stems of Fortification in which casemated defence in the main works and in the caponnieres becomes the essential characteristic a system which has proved more fertile in results in modern times than the bastioued system.