653 



SIEGE. 



SIEGE. 



554 



musketry, which, being nearer, is more effectual than that of the 

 second parallel. Howitzer batteries, //, &c., are formed at the extre- 

 mities of these parallels for the purpose of enfilading the covered- way 

 with shells, and thus destroying the palisades and traverses. As soon 

 as the fires from the howitzers have produced some effect, the oblique 

 trenches may be continued till they arrive at the foot of the glacis, on 

 the capital of each of the works attacked, the branches being directed, 

 as before, towards the exterior of any part of the covered- way from 

 whence the enemy might enfilade them ; and each being prolonged 

 towards the rear about 10 or 12 yards, in order to form places where 

 tools and materials may be deposited out of the line of passage along 

 the trenches. If the defenders should have established redans or 

 redouts at the foot of the glacis, or should have carried out counter- 

 approaches from any of the collateral works, in order to enfilade the 

 trenches of attack, they must be assaulted and destroyed as soon as it 

 is found that the fire from thence impedes the operations of the 

 besiegers. 



A third parallel trench, c c, may now be executed to connect the 

 points of attack at the foot of the glacis ; for this purpose the squads 

 of sappers turn to the right and left from the head of each line of 

 ;ipf i oach, and meet each other, forming as they proceed a trench which 

 is either rectilinear or curved towards the re-entering parts of the 

 fortress, in order to enable the troops in it to fire less obliquely on the 

 branches of the covered-way. This parallel should be made broader 

 than the others, because considerable bodies of troops are occasionally 

 collected in it, and at intervals steps should be made in it long enough 

 to allow a company of men to mount in line over the parapet. For 

 the protection of the troops, the crest of its parapet should be 

 furnished with sand-bags disposed so as to leave between them small 

 intervals (loop-holes) to fire through ; and in this parallel, batteries, 

 A A, &c., for small mortars may be formed, in order that shells may be 

 tin '.\vn from thence into the principal works. It is estimated that the 

 third parallel may be finished by about the tenth night from the time 

 of opening the trenches. 



At this period, should any great necessity exist for hastening the 

 surrender of the place, should also the garrison be weak, and should 

 there be no retrenchments in the covered-way, it may be thought 

 proper by main force to assault the latter, and immediately crown the 

 glacis with batteries for breaching the works. In this case, the 

 defenders should be driven as much as possible from the covered-way 

 by a heavy fire from the mortar and howitzer batteries ; then the 

 troops who are to make the assault, having been assembled in the 

 third parallel, mount, at a signal a little before sun-set, over its parapet, 

 aud proceed rapidly up the glacis. A party of men then extend them- 

 selves along its crest, and by their fire keep down that of the defenders 

 on the parapets ; in the meantime the sappers commence forming with 

 gabions a lodgment on the crest, and the rest of the storming party 

 endeavour to force an entrance through breaches made by artillery in 

 the palisades. When the defenders have thus been compelled to retire 

 behind the traverses in the covered-way, the assailants, who then 

 become exposed to the fire from the parapets of the bastions or ravelins, 

 retire into the lodgment which by this time may be finished on the 

 crest of the glacis ; and during the night there may be executed 

 trenches of communication from the lodgments to the third parallel. 

 The lodgments thus formed may be afterwards connected together, 

 and extended to the right and left if necessary; and in these the 

 ng batteries may be formed. 



Should the fortress have small ravelins, like those of Vauban, the 

 assault may take place at once on the salients of a ravelin and of the 

 two collateral bastions ; but if the ravelins advance far towards the 

 country, as in Cormontaingne's system, it can take place only at 

 I lents of the ravelin on each side of one bastion ; since if it were 

 attempted to carry on the approaches between the two ravelins, the 

 troops and sappers would become exposed to fires on their flanks and 

 in rear as well as in front. 



An assault [ATTACK] by main force is always attended wiih con- 

 siderable lorn, and therefore, if time permits, it is preferred to continue 

 carrying on the approaches by sap. For this purpose, supposing the 

 place to be fortified with largo ravelins (as in the cut), a trench is 

 begun at about 30 yards on each side of the ridge between the two 

 faces of the glacis before the ravelins only, and carried in a curvilinear 

 direction till the two squads of sappers meet on the ridge about eight 

 or nine yards in advance of the third parallel. From hence the trench 

 is continued by double and direct sap along the ridge till it arrives at 

 between 30 and 40 yards from the crest at the angle of the glacis ; and 

 at this spot, formerly, high breastworks, called trench cavaliers, Ic k, 

 Ac., about the thirteenth night from the time of opening the trenches, 

 Were raised on the prolongations of the branches of the covered-way, 

 in order to allow a plunging fire of musketry to be directed into those 

 branches. But as the fire of the defenders' artillery may prevent the 

 construction of such works, instead of them there are now formed 

 batteries armed with small mortars from which balls or stones may be 

 projected into the covt-red-v.-ay in order to compel the defenders to 

 retire from thence. (Mortara for throwing stones are called by the 

 French jiicrrien.) 



After the fire from tho cavaliers or mortar-batteries has obliged the 

 enemy to abandon the advanced parts of the covered-way, double saps 

 are carried on towards the salient angle of the glacis, and when they 



have arrived "at about 24 feet from that angle, the crowning of the 

 glacis commences. This is performed by extending the sap along the 

 crest on each side of the angle, and throwing up the earth towards the 

 place in order to form epaulements for batteries. That the crowning 

 trenches may be secured against the enfilading fires from the collateral 

 works of the besieged, traverses are formed across them at intervals in 

 situations where they may not interfere with the guns to be placed in 

 the batteries ; and, on account of the fire which the enemy may still 

 keep up from the branches of the covered-way and the retrenchments hi 

 the re-entering places of arms (see the figure in art. FORTIFICATION), a 

 portion of a fourth parallel, m m, should now be carried out in order 

 that troops placed there may protect the sappers during the formation 

 of the batteries, and the artillerymen during the operation of breaching 

 the ravelins. The crowning of the glacis is sometimes extended along 

 the faces of the re-entering places of arms ; and in this case trenches 

 on those faces are connected with the fourth parallel by lines of com- 

 munication formed in serpentine directions. 



The epaulements raised by the besiegers between the salient angle of 

 the glacis and the first traverses on each side are to serve as counter- 

 batteries, whose use is to ruin the parapet and dismount the guns in 

 the faces or flanks of the collateral works, in order as much as possible 

 to prevent the enemy from opposing by musketry or artillery the 

 passage which is to be effected across the ditch ; and the epaulements 

 between the first traverses and the re-entering places of arms serve for 

 the breaching batteries. [BREACH.] The crowning batteries on the 

 glacis of two ravelins, r r, are supposed to be finished about the six- 

 teenth night from the time of opening the trenches. 



AYhile the breaches are being formed, the passages by which the 

 descents into the ditches of the ravelins are to take place are com- 

 menced. These are either open trenches or subterranean galleries cut 

 in inclined planes through or under the covered-way opposite the 

 breaches ; each passage thus terminates at a perforation in the counter- 

 scarp about 3 feet above the bottom of the ditch if dry, or at the level 

 of the water if it contain any. The sappers throw fascines into the 

 ditch if dry, till the heap is sufficiently high and thick to secure them 

 from the fire of the defenders, and then getting in, they form by sap a 

 trench and parapet extending some way up the breach itself. Prepara- 

 tions are afterwards made for the assault. 



For this purpose the interior of the batteries and the passages lead- 

 ing to the ditches are during the night filled with troops, in whose 

 rear are bodies of sappers with their materials ; and early in the morn- 

 ing, after a heavy fire has been for some time kept up from the 

 batteries in order to drive off the defenders, the troops charge up, and 

 endeavour to keep the enemy engaged while the sappers execute 

 lodgments on the breaches by filling their gabions with the loose 

 earth ; as soon as these are finished, the storming parties retire behind 

 them, and from thence keep up a fire upon the enemy. These lodg- 

 ments should if possible be on the tops of the breaches, but if the 

 interior of the ravelin is retrenched by a redout, as s a, whose fire com- 

 mands those spots, the lodgments must be formed on the ascent, that 

 they may not be immediately destroyed. It is estimated that the two 

 ravelins may be taken about the eighteenth night. 



If the ditches contain water which cannot be made to flow off, there 

 may be formed across them solid causeways consisting of fascines 

 laden with stones to make them sink, or of casks or gabions having 

 their axes in horizontal positions ; or floating-bridges of timber-logs, 

 casks or pontoons may be constructed ; and by any of these means the 

 troops may pass over to the assault. From the lodgments just men- 

 tioned trenches are carried on by sap directly to the top of the breach, 

 and from thence turning to the right and left they are continued about 

 half-way down the faces of the ravelins : their extremities being made 

 to join the parapets of these works. 



The redouts in the two ravelins are next to be taken ; and to effect 

 this object, it being supposed that the faces of the ravelins are too 

 narrow to allow room for forming batteries on them, either a portion 

 of the ravelin must be blown up in order to allow the fire of the 

 brcaching-batteries on the glacis to act against the redouts through 

 the apertures, or else the redouts must be breached by undermining 

 them. Should the latter method be preferred, a trench or gallery is 

 cut through the mass of each ravelin, and a sap is carried across the 

 ditch of the redout ; the miner then, being secured against the effect 

 of the enemy's grenades by timbers placed in inclined positions leaning 

 against the scarp of the redout, cuts through that scarp and forms 

 chambers for the reception of gunpowder. This being fired, a part of 

 the rampart will be destroyed and a breach formed. An assault is 

 then made by troops, and the defenders being supposed to be driven 

 out of the works, a battery may be raised along the gorge of each 

 redout in order to compel them to quit the tenailles, t t, in the main 

 ditch. The redouts of the ravelins being taken (probably about the 

 twenty-first night), the defenders will also be obliged to retire from 

 the rear extremities of the latter works ; and the besiegers occupying 

 those extremities, then- fire from thence commanding the interiors of 

 the redouts in the re-entering places of arms, these last must also be 

 abandoned. 



The approaches towards the bastions may now be recommenced, as 

 the fires from tho ravelins are no longer to be apprehended ; therefore 

 a double sap is carried on from the curved trench in the third parallel 

 directly along the ridge of the glacis, till it begins to be plunged into 



