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closely followed up by considerable forces, or whether they can retire quietly, and without being exposed to any attack which may endanger them: 6, and lastly, you ought to examine what is the strength of the army, or detachment, its number of cannon, the quantity of stores, and equipage, &c., and regulate accordingly the size of the tête de pont, as well as the passages through it, in order that the whole may file off without stoppage and confusion; all these various circumstances oblige us to make a difference in the size, form, and strength of a tête de pont. If an army or considerable detachment, for instance, is closely pursued by a great force, and can retreat but slowly, either on account of its composition, or because it is compelled to take particular precautions, which require tine, the tête de pont, which is intended to favor its passage across the river, ought to be of a certain extent, and capable of making a good defence; for then, not only the troops, artillery, &c., must file off through it without any obstruction or confusion, but it ought to check the enemy, should he attempt to approach it: on the contrary, if a tête de pont has to cover a communication of no great importance, or the passage across a river, of an army or detachment which is not closely pursued, and can retreat quietly and speedily, it will not require as much extent and strength as the former.

The bridge or bridges, which a tête de pont covers, should be concealed as much as possible from the enemy's sight, as he would batter and ruin them with his cannon; and that, in general, the most advantageous points for constructing those works are where the river bends inwards.

When a tête de pont is to cover only a communication of no great importance, and across a small river, a simple redan will suffice: provided, however, that the river is so shaped as to prevent the enemy perceiving the bridge from some point; but, if he can perceive it, a piece should be constructed, whose flank defends the ground from which the bridge can be seen. These small têtes de pont will acquire a greater strength, if the ground on the opposite bank ailows us to construct small redans where fusileers are placed; these redans ought to be disposed in such manner, that their fire, after grazing the faces of the tête de pont, may cross in front of the saliant, and as near to it as possible; the redan is intended to graze the flank of the piece.

When the river is so broad as to prevent the musketry fire of the redans doing any execution for the defence of the tête de pont, batteries may be constructed and disposed in the same manner as the redans.

A tête de pont which is intended to cover a communication of importance, and necessary for the movements of large bodies of troops, requires a greater extent and strength than the preceding. That represented by fig. 6, plate VI. is capable of making a good defence, particularly when it can be supported by batteries a, placed on the opposite bank; its outline does not differ widely from that of a redan, except that the faces are broken, in order to procure the two flanks be

and de, the direction of which ought, in general to be as perpendicular as possible, to ef and df, which they defend. Care must be taken, however, that they are not exposed to be enfiladed, which depends, of course, on the configuration of the river, and the disposition of the surrounding ground.

Sometines, also, a tête de pont may be composed of a horn work, the inside and branches of which are defended by batteries a, erected on the opposite bank. When the ground does not allow you to construct these batteries, the branches of the horn work may be broken.

Half a square fort, with bastions, makes a strong tête de pont, particularly when you can construct on the opposite bank batteries and intrenchments. Half a star-fort, or redoubts so disposed as to flank each other, may also be used for a tête de pont.

Of intrenchments of armies.-The whole of the works and obstacles by which an army or a considerable body of troops cover themselves, for their own defence, may be called intrenchments of armies. In general the object is, to interpose between themselves and the enemy a defensive line, whose protection may compensate for their inferiority in number; this line may be composed of parts so connected together, that no uncovered space is left between them, in which case it is called a continued line; or those parts may be isolated from each other, and uncovered intervals left between them; and then it is named a line with intervals.

Intrenchments of armies can seldom be composed of regular and similar works, nor even of works different in their nature, but symmetrically disposed, and so constructed, that all those of the same kind may have the same dimensions; for, on account of the ground, or because of a necessity to direct more fire to certain points than to others, some irregularities will be requisite; thus it is impossible to foresee all the variations that may occur in the tracing of intrenchments of armies; wherefore no particular rules can be given for every case; there are, however, general principles which ought to guide an engineer.

The works most commonly used for intrenchments of armies, in a continued line, are redans, tenailles, or queues d'hironde, cremaillères and bastions; hence intrenchments take the name of intrenchments with redans, intrenchments with tenailles, or queues d'hironde, intrenchments with cremaillères, and intrenchments with bastions; sometimes also lunettes are placed in front and to a certain distance from a main intrenchment, which is then called intrenchment with lunettes.

For the detailed construction of these works, we must refer the reader to the professional publications on the subject.

The following general principles should be observed, as much as possible, in the formation of intrenchments of armies.

1. Their flanks must be supported, and not exposed to be turned; for, of what avail would be the defence in front which intrenchments afford, could they be attacked in the rear?

2. Their extent should be proportionate to the

strength of the army which they cover, since they are to be defended by it.

3. In tracing those intrenchments, you ought to avail yourself of every natural accident of the ground which they traverse; a low and marshy spot, a stream whose banks may be overflowed, a ravine, a wood where an abatis may be formed, and other natural obstacles, frequently afford great advantages, when properly connected with the other defences; either by increasing the strength of some parts of the line, or, when they suffice to stop the assailants, by saving you the time and labor, which, without them, the construction of works would require.

4. The line formed by intrenchments of armies should occupy, as much as possible, the elevated parts of the ground which it crosses, and border the summits of the heights or hills in its direction; by which means the intrenchments will have a superiority over the assailants, who cannot approach them without passing through uneven and difficult ground.

5. Every point of the ground, in front of an intrenchment, must be seen and defended by some of its parts.

6. The habitations in front of the line should be occupied and fortified, when they are sufficiently near to be supported by it; but should they be too distant, and so situated as to conceal the movements of the enemy, they must be destroyed.

7. For the same reason, a wood, which the line can support, must be occupied; but should its distance prevent it, and its situation be such as to conceal the movements of the assailants, it requires to be cut down.

8. The line ought to cover all the habitations in its direction, so as to make them serve as points of support, and to reap advantage from their reverse fire.

9. The number and strength of the respective works, depend on the greater or less danger to which the part of the line where they stand may be exposed; if, for instance, the enemy could scarcely approach it, and should he not be able to bring his cannon against it, the works thrown up for its defence, would undoubtedly not require the same extent and strength as they would, in case the assailants could easily approach and batter it.

10. All obstacles which may obstruct the communications of the line, with such parts in its front as must be protected by it, or which may impede the retreat of the army, should the intrenchinents be carried, must be removed.

Intrenchments with intervals are now preferred to those which form a continued line. The following are the reasons which are assigned for it; 1st, the former require less troops for their defence than the latter; so that, with an equal number of men, a greater force can be placed at the most exposed points, or stronger reserves kept; 2dly, the intrenched army can form in such order as will not impede its movements; wherefore it will be able to pass successively from the defensive to the offensive, and vice versa, according as circumstances may require whereas, on the contrary, an army placed behind continued intrenchments must be de

ployed; and, as it can scarcely execute any movements outside of them, it is reduced to defend passively, if I may use that expression, the works which cover it, and are sometimes very imperfect: 3dly, a line with intervals requires less labor than a continued line; therefore, the works which compose it can be constructed with greater care in the same time, and with the same number of workmen. Lastly, the former line is more easily adapted to the ground than the latter; as the engineer, who is not confined to a fixed tracing whose parts must all be connected, can place the works at the most essential parts of defence.

In the late continental wars frontiers of countries have been the frequent objects of attack and defence. They constitute important objects of field fortification. M. Malorti furnishes some excellent directions for forming the principal works of this kind.

i. Of lines of frontiers.-The works and obstacles disposed along some open parts of a frontier, to shut up the country from one place, or post, to another, are called lines of frontiers.

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These lines may answer very useful purposes; first, they protect the army which defends the country behind them, and also to secure its movements; secondly, they prevent the incursions of the enemy's parties, and the devastation which they would occasion; thirdly, they remove the fears of the inhabitants, who then attend to agriculture. Lastly, they connect the defences of the frontier, and therefore increase the resistance which can be made. Indeed, a line of frontiers will not afford those advantages, unless it be considered in its proper light and used accordingly; for should the army consider it, as forming its own intrenchments, and actually defend it, as lines of frontiers have in general a greater extent than is proportionate to the strength of the army, it follows that the troops would be weak every where; and that they would undoubtedly be crushed by the columns which the enemy would march to several points at once; thus the line would be disadvantageous rather than useful; but on the contrary should the army support it only with a limited number of troops, and occupy a position behind, from which it could repair rapidly to all points, and take in flank the enemy's columns when they begin to advance, no doubt can be entertained, in this case, of the utility of the line, and particularly when its extent is not so great as to preclude the army from the possibility of supporting all its parts; for the enemy will be compelled to form partial attacks, and therefore to weaken himself by dividing his forces. The following are the general rules to be attended to, in the construction of lines of frontiers.

1. They require, like intrenchments of armies, that the extremities should be supported, and not exposed to be turned. Should a line of frontiers be very extensive, it must be directed from one fortress to another, when there are any on the frontier.

2. Their front ought not to present any unprotected openings, by means of which the enemy may penetrate into the country which they are intended to cover. The reason is evident,

since a line of frontiers is chiefly intended to shut
up the country which it covers.

3. When you are to construct a line of fron-
tiers, you should avail yourself of all the obsta-
cles which the ground that it traverses may offer.
4. That the line may have points of support,
the open towns and villages enclosed by it should
be fortified; this is particularly requisite when they
Occupy important points, and when, by their situ-
ation, they can see in reverse some other parts of
the line.

5. As all the points of a line of frontiers are not equally accessible to the enemy, the obstacles which form it do not all require the same degree of resistance; for instance, should some parts of the line traverse an open country, through which the enemy might easily penetrate, whilst others pass over a marshy or woody ground, &c., which scarcely allows him to approach, the former would undoubtedly require stronger defences than the

latter.

6. Since a line of frontiers is chiefly intended to secure the country behind it from the enemy's parties, the works which it contains do not require a greater relief than that which field-works commonly have; not even in its most accessible points; and, according to circumstances, from three to eight feet at most will suffice for the thickness of their parapets. It is scarcely necessary to observe, that the former dimension is applicable to such works as are only to be secured from the fire of musketry; and the latter to those which may be attacked with cannon.

7. Great advantages may be derived from streams, and particularly when they are broad and deep and have steep banks, or when the ground on their banks is marshy; should they contain islands, those on the side of the army must be occupied, in order to prevent the enemy from throwing up defences within them, under the protection of which he could more easily pass the stream; with regard to those on the the other side, they ought to be observed by posts which are ordered to retreat when the enemy appears with a superior force; all thickets, brushwood, &c., which might favor and conceal his movements, should be cut down. It is less important to occupy those islands than the others; besides, should they be attacked, you could not keep them on account of the impossibility of conveying a sufficient force to defend them.

8. All fords must be guarded by strong posts, and no bridges suffered to remain, except those which are indispensably necessary to penetrate into the enemy's country, should circumstances require it; when they are not situated within a fortress, or protected by it, the place where they stand should be more or less strongly fortified, according to the importance of the passage, and to the greater or less facility which the enemy may have of approaching them.

9. A small stream may also be rendered serviceable, by means of dams thrown across its bed; so as to form small inundations which render the access to the low parts of the ground more difficult to the enemy. The sluices of the water mills, manufactories, &c., which are commonly found on the banks of such streams, may be used likewise to that purpose, and those

buildings should be fortified. Morasses too, the enemy cannot attempt to pass them without and even marshes, are a very good barrier, as danger, and particularly with his cannon; therefore, when the disposition and direction of the line allow some parts of it to be protected by such obstacles, you ought to avail yourself of them.

cessible points of a ravine, and on those whence 10. A few redoubts placed near the most aca reverse fire can be most easily obtained, will suffice to defend such passages.

the line, may also procure advantages by means 11. The woods which are in the direction of of abatis made within them, and supported by a few detached works. The ground in front of the abatis should be cleared to a certain distance, in order that the enemy may not conceal his movements and approach unperceived.

12. Should a mountain be in the direction of sufficiently strong to secure them. the line, its passages must be guarded by posts

protected by natural obstacles, works ought to be 13. Wherever the country is open, and unthrown up, whose requisite strength depends on the importance of the points which they cover, the facility which the enemy may have of approaching them, and on the advantages which the ground affords for his manœuvres.

Posts of frontiers are intended to secure, with a ii. Of Posts of Frontiers and other Posts.limited number of troops, the principal points of by fortresses, the number, situation, and extent a frontier which is not defended by an army, nor of which, are properly adapted to localities: for, should it be protected by such fortresses, their garrisons would suffice to guard it. frequently that a frontier is actually defended by fortresses, but that they are not properly adapted It happens to localities: in which case, intermediate points must be occupied by posts, so as to rectify the defects in the defence.

chiefly inhabited, as they are more fertile and In a mountainous country, the valleys are better supplied with water, communications and accommodations of all sorts, than the elevated parts; wherefore the towns, or villages situated within them, or near their openings, and in the plains contiguous to them, are particularly suitable to the establishment of posts: those which of rendezvous and depôts, should be strongly defend the principal gorges, and serve as places fortified, and preceded by smaller posts, in order to watch the enemy's movements; with regard to the other gorges, they should be guarded by posts whose requisite strength depends on the facility which they may give to the enemy to penetrate into the country.

guard than the preceding; in such countries, the Flat and open countries are more difficult to placed on the communications be more or less chief towns should be occupied, and those strongly fortified, according to the importance of the points where they are situated; intrenched camps, of which we shall speak hereafter, may also be formed, where their position enables them tier. It is particularly requisite that those towns to be of service for the general defence of the fronshould be capable of a strong resistance, which

are situated in fertile plains, as armies attempt generally to advance through the most fruitful parts of a country.

No particular rule can be given, with regard to the method of fortifying posts of frontiers, since it depends on the configuration of the ground, the time which you can command, &c. But, as those posts are intended to serve instead of fortresses, particular attention must be paid to the dispositions for their defence; and that you should avail yourself of every advantage which localities may offer; a stream which allows an inundation to be formed, or whose passage may be rendered difficult to the enemy by other convenient means, an impassible morass which secures part of the post, or a marshy ground which obstructs the approach to it; a wood where an abatis, properly supported, can be made; or which must be entirely cut down, as it would conceal the enemy's movements, and expose the post to be surprised; buildings, which, being placed between two works, form a sort of curtain connecting their defences, and whose walls may be pierced with loop-holes; or which project in front of the post, and will flank part of it, after being secured by works, or by other practicable dispositions: some other buildings which must be pulled down, either because they would mask the fire of the post and render it less effective, or because they would favor the enemy's approach, and enable him to see into the post; a street, which should be barricaded, or cut across by trenches: some particular points, where works must be thrown up, as, on account of their situations, their fire will flank other works, or defend them in reverse: a ravine, a ditch, a steep ground, &c., which may strengthen the defence, or which would weaken it, should not proper precautions be taken: these, and other considerations, which circumstances may require, should fix the attention of an engineer, in forming his plan for the defence of a post, and, if he cannot depend upon sufficient time to complete all the dispositions which are requisite, he must attend, first, to the most essential; next, to those which are less important; and ultimately to the formation of such works and obstacles as will improve the defence of the post, although it may not indispensably require them. The first step to be taken, in such a case, is to secure the post from a coup de main. It is scarcely necessary to observe, that the defences thrown up for that purpose must be so disposed as not to prevent the addition of others, should circumstances permit it.

Let us suppose that an army intends to invade the territory of the enemy, and to remain therein; in this case, the march of the army requires particular precautions suitable to the nature of the frontier through which it proposes to penetrate: for instance, should the frontier be protected by fortresses well calculated in all respects for its defence, they must be taken as the army advances, and then be repaired, garrisoned, and supplied with stores and provisions, in order to keep in awe the invaded country, and afford points of support which may secure the army's retreat, should it be compelled to fall back, and supply all its wants; but if the country is open,

and destitute of fortresses, posts strongly fortified must be established near the principal communications, and in the points most advantageously situated to defend it, and secure the army's retreat, if necessary; indeed, less precautions are requisite, when the army which invades such a country intends only to make a temporary stand, either to levy contributions, or to draw in the enemy and make a diversion; however, it should occupy, as it advances, the principal communica tions, and the positions which will secure its flanks and rear; as, otherwise, its subsistencies would be continually exposed to be burnt or taken away by the parties of the enemy; besides the rear of the army would be annoyed, and the army, perhaps, be cut off.

The winter quarters of an army, and particularly in a hostile country, should also be covered by posts so placed as to defend the principal communications; for without it the quarters will not be secure, nor will the troops enjoy any repose, as they may be attacked at every moment: nay, should the enemy take the field early, and attack the quarters before they have time to assemble, he might crush them, and thus destroy part of the army in the beginning of the campaign.

As all posts should be fortified according to the same general principles, we refer the reader to the hints which we have given, when speaking of posts of frontiers.

iii. Of intrenched Camps of Frontiers.-Some of the positions to be occupied along a frontier, for its defence, may not be inhabited, or the number of habitations which they contain may be too small for the troops, which in those two cases must be encamped; and then the positions take the name of intrenched camps of frontiers.

There are two sorts of intrenched camps of frontiers; namely, those which have a small extent, and are only intended to guard the points where they are placed; they differ from posts of frontiers, of which we have been speaking in the preceding section, merely because they are situated in an uninhabited place; and what we have explained, with regard to the former, is also applicable to the latter, with some modifications which the difference in their situation may require. The other intrenched camps of frontiers contain a considerable body of troops, and are intended not only to guard the points where they are established, but to cover the country; these camps, which are formed for the same purpose as flying camps, and only differ from them as they are fortified, afford great advantages, when properly disposed; they keep the enemy in check, and prevent him from penetrating through some weak points of the frontier, in order to advance in the country; for then his flanks and rear would be exposed to be attacked by the en camped troops, as they can march in all direc tions; his lines of communication would not be safe, and his retreat might be cut off. It is evident that camps of this sort require to be so for tified as to afford a resistance proportionate to their object, and to the importance of the points which they occupy; and that their situations must be such as not to expose them to be rapidly and unexpectedly surrounded; for the troops

could not march to the tnreatened points, nor make good their retreat when their safety required it; and therefore they would be exposed to no purpose.

The proper situation for an intrenched camp of frontiers requires, likewise, that it cannot be taken in reverse, nor the troops prevented from retreating or communicating with other parts of the frontier, according to circumstances; and that the enemy may not, by crushing some posts, oblige the encamped troops to withdraw from their intrenched position, for fear of their retreat being cut off. Lastly, it should be examined, whether the situation of the camp affords easy means to penetrate into the enemy's country, should such offensive movement be requisite, and whether it can be placed in a spot protected by some natural obstacles, as then it will require less time and labor in fortifying.

iv. Of grand têtes de pont.-When part of a frontier is covered by a river, it is necessary to secure the principal communications across it, so that an army may march to the enemy's country, or retreat from it, according to circumstances: grand têtes de pont are constructed for that purpose.

It is evident that grand têtes de pont ought to be capable of a great resistance; for, as their object is very important, the enemy has a material interest in destroying them; they require also a rather considerable extent, in order to contain a sufficient number of troops to check him, when the army is advancing or retreating through them. Lastly, they must be so disposed as to prevent him from perceiving the bridges which they encompass; otherwise he would attempt to destroy them from a distance, with his

cannon.

When the communication to be secured is situated in a town, and not seen from without, the part of the town beyond the river must be fortified, and then it serves as a tête de pont.

But should the opening of the communication be outside of the town, and seen from the country, not only the town must be fortified, but the opening requires to be covered by works sufficiently extensive to hide the bridges; or the points from which the enemy can see and batter them must be fortified.

Lastly, if the communication is at a certain distance from the town, its opening towards the enemy should be fortified, and the requisite precautions taken to secure the bridges from being battered.

It happens frequently that these grand communications across rivers are only established in time of war; wherefore, the bridges which form them have no great solidity: in this case, stoccados should be constructed in the upper part of the river, so as to stop every thing which the enemy may let go with the current, to break open or destroy the bridges. When there are islands near a tête de pont, those whence the enemy could take it in reverse or batter the bridges should be fortified.

A single house, when it has no stone walls, may be fortified in the following manner: the walls may be strengthened by boards in the inside, or by rafters applied as in blockhouses, or,

if these are wanting, by making a ditch round it, and using the earth to strengthen the wall. The doors and windows are fortified with boards, and barricadoed. Loop-holes are every where made, but in such a direction that the enemy cannot reach them with his firelocks, so as to fire into the inside of the house. If there is no ditch round it, other impediments are to be made use of, to hinder the enemy from approaching close to the wall. The roof is broken down, and all combustible matter covered with earth and rubbish, to defend the house from an attack from above, which might otherwise be executed by ladders. In a stone house, the walls will generally be strong enough, or, if not, they are to be prepared as above. The same is also to be observed respecting the windows and the roof; and, if possible, it is to be made shell proof from above. The doors are either barricadoed, or defended by a tambour constructed before them, to have a flanking fire.

A church-yard, a farm, or an estate, is fortified in a similar manner; but, if surrounded by a wall, either loop-holes are made through it, or, if too high, a kind of scaffolds, called echafaudages, are to be erected, serving for the soldiers to stand upon while firing. The church, or the building on an estate, are then generally used as a corps de garde, and made shell proof, by breaking down the roof and the uppermost story, and using it to cover the building. The doors, and particularly the corners of the walls round such a place, are generally covered by tambours ; but, if time permits, caponniers, and other impediments to the advancing of the enemy, are made use of. The street and roads, leading towards them, are generally made impracticable by old or broken carts, harrows, boards with nails, wheels, &c. All the houses in the neighbourhood, which may be advantageous for the enemy, or which may favor or cover his approach, are levelled, and the rubbish of them used to strengthen the walls. The trees near such a place, if large, are hewed down or sawed off, that even not a single rifleman may approach covered by any of these parts.

A small, or country town, if surrounded by a wall, is fortified in a similar manner; but echafaudages are generally used behind its walls, and, if possible, two rows of soldiers are employed, one firing through loop-holes, and the other over the walls. Guns are placed wherever their fire is of the best effect. The gates are barricadoed, and covered by impediments which hinder the enemy from advancing; besides this, they are covered by traverses, and a flanking fire is established before them, if possible. Only such parts of the gates as are essentially necessary to be open for the communication are not barricadoed, but strongly defended, while every thing is to be done that may render the interior communication better and more easy, by means of sufficien passages.

PART III.

ON THE ATTACK OF FORTIFIED PLACES. It has been suggested that our treatise on the above art requires some detailed mode of attack, as one of the best exemplifications of the doc

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