FORTIFICATION. 



m some instances expedient, as above de- 

 scribed, to direct all the force exteriorly, 

 especially where the outwork lays upon 

 a navigable river, and that ships can be 

 brought to bear upon the works,) the re- 

 doubt must be lowered to the same level 

 of terre-pleine as the raveline : and, in- 

 deed, it may even, in some few instances, 

 where A must be completely screened 

 from the exterior, be proper to sink the 

 terre-pleine of B so very low, that its can- 

 non may just graze the terre-pleine of 

 the raveline C ; making the parapet of a 

 due height, and forming a substantial 

 shed of three inch boards, &c. nearly flat, 

 over the banquette, at a foot above the 

 crest of the parapet. This prevents the 

 enemy from commanding the terre-pleine 

 of the redoubt, while, at the same time, 

 those defending it would do ample exe- 

 cution through the narrow slit, or open- 

 ing, between the crest and the shed. 

 The latter would effectually keep off 

 grenades, &c. and give the defenders 

 great confidence. The dotted lines above 

 the rampart A, shew the height to which 

 its parapet would necessarily be raised, 

 if B were elevated even a foot and a half 

 only above C. The dotted line from C 

 towards B shews the level to which the 

 genouliere, or crest of the lower slope of 

 the embrazure. may be brought, so as to 

 allow the fire from B to graze the terre- 

 pleine of C, and to drive the enemy from 

 the raveline. 



Relinquishing the explanation of what 

 relates to the more scientific parts of the 

 topic, we must now enter upon the de- 

 scription of many other matters, indis- 

 pensably necessary on this occasion. We 

 have already spoken of bomb-proofs. 

 These are vaulted chambers, either run- 

 ning under long arches, or groined, and 

 standing on substantial walls and pillars. 

 The term very properly implies, that the 

 arches should be sufficiently strong to 

 resist the fall of shells, or, at least, to 

 prevent their penetrating into the cham- 

 bers. It generally demands, at least, a 

 yard in thickness to produce such a firm 

 resistance ; the masonry should be of the 

 very best materials, and put together in 

 a workmanlike manner. The casemates, 

 thus arched over, should be further cover- 

 ed with three or four feet of soil, where 

 such an addition would not raise the terre- 

 pleine too high : for, by allowing a shell 

 to bury itself completely, its splinters do 

 not occasion half so much mischief, as 

 when the explosion is more superficial; 

 although a quantity of soil may be thrown 

 out. Perhaps the best contrivance for 



small casemates, defended by breast- 

 works, is the giving them such a slope as 

 may cause shells to fall into pits, &c. so 

 as to do no damage. Such pits answer 

 well in the centres of round or polygon 

 redoubts, where only a parapet is left 

 around the top, and might, perhaps, be 

 advantageously made in the centre of 

 block-houses, &c. 



In the formation of magazines, for 

 ammunition, the arches are usually made 

 double, that is, one greater arch covers 

 two smaller ones; the latter resting on 

 a central pier, as seen in fig. 5. In this 

 case every arch should be bomb proof, 

 and the roof should be pitched; the end 

 falling off by a gradual rounding, and 

 the whole well supported by buttresses. 

 The walls of magazines are generally 

 double; the buttresses are sometimes 

 pierced at their sides with small loop- 

 holes, for the admission of air and of light 

 to the surrounding passage. All the fast- 

 enings should be of brass or of copper, 

 and no wood or iron allowed in any part 

 whatever. 



The ramparts are ascended by means 

 of long slopes, called ramps, laying in 

 general parallel with and leaning against 

 them : these ought always to be broad 

 enough to admit a gun passing up and 

 down, mounted on its carriage. The 

 ramps into solid bastions sometimes di- 

 verge into three branches, of which two 

 lay along the insides of the adjoining 

 curtains, while the third runs straight up 

 in a line with the capital, i. e. with the 

 centre of the gorge, pointing towards 

 the saliant angle. Thus H C is the capi- 

 tal of the bastion 4. fig. 1. Horseshoe ca- 

 valiers have usually but owe ramp, placed 

 in the centre of the rear, as shewn by 

 the two parallel lines proceeding from 

 that in the bastion C, of the crown work 

 M. fig. 1. 



The proper arrangement of streets 

 within fortined towns is of the utmost 

 importance, by contributing essentially t* 

 the ready resort of troops to their posts, 

 and facilitating the supply of stores. 

 Every avenue ought to have a barrier, 

 both to keep the inhabitants under pro- 

 per controul, and to prevent the effects 

 of various stratagems in behalf of a sur- 

 prise. Those houses which command 

 the interior of the works should be al- 

 ways reserved for the habitations of the 

 garrison, and should likewise be supplied 

 with small quantities of . m -.in -lion. 

 The arsenals should be con. ' ' ver- 

 ed from the fire of '.(?' - - vries; 



and, together \vith every building ap- 



