FORTIFICATION. 



WWI 



I 



w% 



lov 

 qu 

 wil 



3 



ce 

 !o< 



The bonnet, mentioned in the pre- 

 ceding paragraph, is nothing more than 

 an angle made parallel to a raveline, 

 and not far removed from it, so that 

 the faces of the latter command the 

 faces of the bonnet. This out-work 

 comes down to the lunettes, by which it 

 is flanked. 



We now have to treat of those im- 

 portant parts, the glacis, and the covert- 

 way. The former is a gradual slope, 

 commencing at a distance from the ex- 

 terior of the out-works, seldom less 

 than fifty yards, and when within five 

 toises of the ditch, stops abruptly, oc- 

 casioning a sudden fall, never less than 

 seven, nor should it be more than 

 ne feet. Here it is supported by a 

 vetement, and is partly met by a ban- 

 ette of turfed soil, which is raised 

 gh enough to come within four feet 

 and a half of the crest, or highest 

 part of the glacis. At the foot of the 

 revetement, at such distance as ;may 

 prerent an enemy jumping over, say 

 from two to three feet off, a row of 

 palisades is fixed ; these are strong pales, 

 nine feet in length, of which one-third 

 is buried in the banquette, while the 

 long horizontal rails, to which the pali- 

 sades are firmly nailed, are at every ten 

 feet morticed into square posts. The 

 lower rails are one foot from the ban- 

 uette, and the upper ones are just level 

 ith the crest of the glacis, so that the 

 Idiers may fire through the top inter- 

 's between the pales, resting their pie- 

 ces on the upper rail. 



The primary defences are in the co- 

 vert-way, but they are only for musquet- 

 ~*y ; as this part, owing to its laying very 

 ow, is subject to be enfiladed, and also 

 because the saliant angles of the covert- 

 way are sometimes abandoned from va- 

 rious causes, there are at every forty 

 or fifty yards parapets, whose slopes 

 ~ ^int towards the exterior, or saliant 

 gle of the covert-way, so that cannon 

 ot may be stopped, and the defenders 

 ay make a stand, from time to time, 

 hind these parapets, (which are called 

 iverses,) until at last forced into the 

 t-works for safety from the pursuing 

 emy. Each traverse is made the whole 

 readth of the covert-way, namely, 30 

 ~et; their exterior ends would touch 

 e palisades, were not little inlets made 

 at right angles into the crest of the 

 glacis, broad enough for two or three 

 men to pass abreast. The traverses 

 may be about six feet high within, and 

 about five without ; there is a banquette 



within which raises the defenders about 

 a foot and a half, for them to stand upon, 

 and to fire over the parapet, of which 

 about ten feet is generally the thickness. 

 Another method of passing the ends of 

 the traverses is not uncommon, and is, 

 perhaps, at least equally good as the, 

 foregoing ; this is by making a serrated 

 line of palisades, as seen in the plate, in 

 which the small black projections from 

 the line of the ditch represent the tra- 

 verses, and the line bordering the glacis 

 g,g, g t shews the line of the palisades ; 

 not unlike the teeth of a key-hole saw. 

 The vacant spaces -j~, -f , +, -f , in the 

 re-entering angles, are for the assem- 

 bling of troops for the defence of the 

 covert-way, and are called places of arms. 

 In these, sometimes, small redoubts are 

 thrown up. Places of arms are always 

 near to some sortie from an out-work, 

 so that the parties posted in them may 

 be readily withdrawn, or be reinforced ; 

 in some instances, however, places of 

 arms are made in the saliant angles of 

 the covert-way ; but they should then 

 be in some measure entrenched, or pro- 

 tected, else they would be severely, and 

 perhaps unnecessarily exposed, although 

 the covert. way is so far above their heads, 



The glacis is always made so as to give 

 an inclined plane, corresponding with 

 every change of direction in the line of 

 the crest of the glacis ; not, however, 

 adverting to the small inlets, or serrated 

 appearance, required for passing the 

 ends of the traverses. This will be seen 

 on reference to the plate, where every 

 such inclined plane is particularized. 

 Such a disposition of the glacis is in- 

 dispensable ; it gives the true direction 

 of every part, as it respectively stands 

 fronting to the line of palisades ; so that 

 the soldiers can scarcely fail to aim pro- 

 perly, if they fire straight before them, 

 and rest their muskets on the upper 

 rail. They thus graze ^the surface of 

 the glacis, and consequently do great ex- 

 ecution. 



An extensive defence, called a horn- 

 work, is sometimes substituted for a 

 crown-work. The latter, as may be 

 seen, is composed of a full bastion be- 

 tween two curtains, whose exterior sides 

 are terminated by demi (or half) bas- 

 tions ; whereas the horn-work, in lieu 

 of expanding as it recedes from the prin- 

 cipal, contracts, and its front, (which 

 should be parallel to that of the prin- 

 cipal when it covers a curtain therein,) 

 is formed only of a curtain, terminated 

 by two demi-bastions, The out-works 



