Friedrich Engels

Bastion

Written about 14 September.

From the English.

["The New American Cyclopædia", Vol. II]

Bastion.—  
In ancient fortifications, the walls of cities were flanked by round or square towers, from which the archers and war engines could direct their projectiles upon the storming enemy after he had been brought to a halt before the ditch. With the introduction of artillery in Europe, these towers were considerably enlarged, and early in the 16th century the Italian engineers finally built them polygonal, instead of round or square, and thus developed the bastion. It is an irregular pentagon, one side of which is turned towards the interior of the fortress, so that the opposite salient angle points towards the open field. The two longer sides forming the salient angle are called faces, the two shorter sides connecting the faces with the town wall or the rampart are called flanks. The faces are intended to return the artillery fire from a great distance, while the fire from the flanks is to protect the ditch. The first Italian bastions still showed traces of their origin from the old towers. They were joined closely to the main ramparts; the salient angle was very obtuse, the faces short, and the parapet faced with masonry up to the very top. In such small bastions, the main task of the flanks was the defence of the ditch in front of the curtain which connected two bastions. Hence the flanks were laid out at right angles to the curtain. These bastions were either distributed on the angles of the polygon forming the whole enceinte of the fortification, or, when one side of the polygon was so long that a part did not lie within the effective small-arms fire of the two projecting flanks, an intermediate bastion, called piatta forma, was constructed in its centre. With the improving siege artillery of the 17th century, larger bastions became necessary, and the curtain very soon lost its importance, since the bastions now became the

main objects of attack. The function of the flanks was also changed: they now had chiefly to sweep the ditch in front of the face of the opposing bastion, and instead of being perpendicular to the curtain, they were laid out perpendicular to the prolongation of that face, which was called the line of defence. The height of the masonry facing was so far reduced that the glacis or the parapet of the lower outworks protected it from direct fire. Thus the bastions, in the hands of the representatives of the old French and German school, and later with Vauban and Coehoorn, underwent many changes in form and size, until about 1740 Cormontaigne published a work on the system of fortification with bastions; his system was generally held to be the most perfect in this field. His bastions are as large as possible; his flanks stand almost, but not quite, perpendicular to the lines of defence, and great improvements were made in the outworks.

Bastions are either full or hollow. In the first case, the whole interior area is raised to the level of the rampart; in the latter, the rampart runs around the interior of the bastion, wide enough to allow the working of the guns, and leaves a cavity in the centre of the fortification. In full bastions, cavaliers are sometimes erected: fortifications whose sides are parallel to those of the bastion and raised high enough to enable the cannon to fire over the parapet. In the commanding height of such cavaliers, guns of the greatest range are generally placed, to harass the enemy from a greater distance.

The system of fortification based on bastions was the only one known from the 16th to the end of the 18th century, until Montalembert produced several new systems without bastions, among which the polygonal or caponier system for inland fortresses and the system of casemated forts with several storeyed batteries have found the most approval.