238 



FORTRESS. 



nrit, ought to be filled with water. Outside of the 

 ditch, a low breastwork (the space within which is 

 called the. covered way) surrounds the fortress, and 

 sinks to the level of the field, with a gentle declivity 

 (the glacis), so constructed that every shot from the 

 rampart can graze its surface. The outworks and 

 the particular defences, such as mines, towers, block- 

 houses, abbatis, palisades. &c., lie partly in the ditch, 

 partly in the covered way, and partly yet more in 

 advance and separate from the fortress. The Italian, 

 Spanish, French, Dutch, &c. systems of fortification 

 are all different. They differ in respect to the ar- 

 rangement of the parts, the contrivance of the lines 

 of defence, and the more or less artificial combination 

 of the same works. The annexed illustration of one 

 of Marshal de Vauban's systems of fortification, who 

 was engaged in the service of Louis XIV., will 

 give the reader an idea of the signification of the 

 names of the principal parts of a fortress. 



The part C A B D is called the bastion. C A 

 and A B are walls called the faces of the bastion, and 

 C G, B D are the flanks ; D H is the curtain the 

 distance G D the gorge of the bastion. A is called 

 the flanked angle, and a line drawn from this angle 

 to the farther end of either of its corresponding cur- 

 tains, as H, i.e., the line A H, is called the line of 

 defence. The angles C and B are called the angles 

 of the shoulder, and the angles G D H are angles of 

 the flank. Within the fortification two lines are 

 drawn, running parallel to the outline of the works, 

 G C A B D H E, one at the distance of three toises 

 (French), and the other at eight ; the space between 

 them is called the rampart, and the space between 

 the wall and the nearest line is called the parapet. 

 Within the rampart, and at a distance of four feet 

 from the parapet, there is a small step raised called 

 the banquet. The rampart is elevated above the 

 ground ten or twelve feet, as circumstances may 

 require, the banquet being raised two or three feet 

 higher, and the parapet four feet higher tlian this, in 

 order to defend the men standing upon the banquet 

 from the fire of the besiegers. 



Castriotto invented a method of fortification by 

 bastions as early as 1584 ; and, ten years afterwards, 

 another was given by Errard de Bar le Due. The 

 method proposed by Narchi, in 1599, is shewn below. 



The method of count de Pagan, invented in 1645, 

 is shewn below. It consisted of one or other of two 

 forms, one with an envelope, shewn in the portion of 

 the figure to the left of the line A, and the other with 

 counter guards, as seen on the right side of the line A. 



Vauban, mentioned above, followed Pagan, and 

 besides improving on the system of that scientific 

 military engineer, prepared three different methods 

 that still go by his name, and which are described in 

 his treatise " De I' Attaque et de la Defence," Paris, 

 1737. The first of these methods is shewn in the first 

 engraving in this article, and bears the date of 1680. 

 The second method was suggested on his being sent 

 to repair the fortifications of Landau, in 1684, which 

 was surrounded by a wall having high towers at the 

 angles. He constructed large bastions round these 

 towers, and thus effected a double defence. The 

 third method, represented below, does not differ mate- 

 rially from the second. It was executed at New 

 Brisac in 1698. 



Baron Coehorn invented three different forms of a 

 fortification, chiefly adapted for low and swampy situa- 

 tions ; the second of these, described in lus work, is 

 shewn below. 



The last of the systems of fortification which we 

 shall illustrate, is that of M. Montalembert, eminent 

 as a man of science and a military oflicer, in the latter 

 part of the eighteenth century. Montalembert's sys- 

 tem was so much approved of by Napoleon, that he 

 adopted it in the fortification ot Alessandria. 



A fortress is valuable as a breakwater against the 

 stream of a hostile invasion ; as a bar before passes 

 which do not admit of being turned ; as a fulcrum or 



