Chapter III

Mahan’s Outpost


157. Among the most important modern additions to the military art, is that of topography, or the study of the natural features of positions, with a view to turn them to account in the first dispositions for battle, and its various succeeding phases.

158. It is only by this study that the coup d’oeul militaire, or the art of disposing troops in harmony with the ground on which they are to act, can be brought to any high degree of perfection; whatever may be the natural gifts of the individual.

159. This study is not altogether of modern origin. Among the ancients, some of the Greek generals have given evidence of a feeling of its importance; as in the examples of Epaminondas, Xenophon, Alexander, and particularly of Philopoemen. The Romans, although having adopted an order of battle which lent itself better to varied features of ground than that of the Greeks, still showed but little knowledge of this branch, until after the wars with Pyrrhus, when the art of Castrametation underwent some change with them.

160. The tactics which grew out of the French Revolution gave to topography great prominence; and no general perhaps has ever displayed more consummate attainments in this respect than Napoleon; whose descriptive memoirs, particularly of the Alps, are considered as models for all graphic writings; presenting with clearness and comprehensiveness, a picture that the mind’s eye cannot fail to seize.

161. The term Position is applied to any ground taken up by a body of troops either to make, or to receive an attack.

162. To select a position understandingly, an officer must possess a thorough practical knowledge of the tactical combinations of the different arms; their respective qualifications for the offensive and defensive; and of the adaptation of ground to their particular maneuvers.

163. In choosing a position, the ground must be examined not only with respect to its peculiar suitableness to the object in view, but also with reference to the influence of that in its vicinity upon this object.

164. The first point to be looked to is the extent of the position. This should be such that, deduction made of the advanced-posts, and of the reserve, its front and flanks shall present an unbroken line of troops, from which a close and well-sustained fire can be brought upon all points by which these can be approached. In estimating the front of a position, an allowance of about 180 yards may be made for each battalion, from 600 to 700 strong; about 60 yards for each squadron of horse of 48 files, the necessary intervals between these units being included in this estimate; and from 12 to 20 yards for the interval between the pieces of a battery.

In estimating the depth, an allowance of 600 to 800, yards at feast, should be made from the front to the rear; in order that the two lines and the reserve may be posted in suitable relative positions

165. The position should offer no features by which the prompt movement of troops from one point to another, for mutual support, might be obstructed. Its debouches to the front for offensive movements, as well as those to its rear in case of retreat, should be ample. It should be beyond the effective cannon range of commanding heights both on its front and flanks.

166. The flanks, being the weakest points of body of troops, must be secured from being turned, or attacked; by resting them upon some strong natural feature of the position, as a river, precipice, &c., which the enemy can neither turn, nor seize upon; or else on some point that will afford sufficient means of prolonging the resistance to enable reinforcements to reach it in time, as an entrenched village, a field work, &c. When the flanks cannot be secured in either of these ways, they must be strengthened by an accumulation of troops upon them; to offer a vigorous resistance to the enemy should he attempt an attack.

167. Positions for the Defensive. When a position is taken up to maintain a strictly defensive attitude, the natural features of its front should be of a character to prevent an enemy from approaching in good order; and to enable the assailed to dispute, with advantage, every foot of ground. The enemy, moreover, should not be able to turn the position, when it is unavoidably exposed to this maneuver, without great risk to his own safety, by an offensive movement of the assailed on his flanks, or rear.

168. The manner of disposing and handling troops in a defensive position will mainly depend upon its natural features. The only rule that can be laid down is, to post the different arms upon ground best adapted to their respective tactics; and in such relative positions as to afford mutual support, and not impede each others movements.

* See Chapters VII, IX, X, and XI, Mahan’s Field Fortification, on Intrenchments, &c., of Positions, &c.

169. The obstructions on the front and flanks of the position will be occupied by the advanced-guard, formed of light troops of each arm, if the ground is favorable to their combined action; for the purpose of observing the enemy, and holding him in check if he makes an onward movement.

170. The main-body of the infantry will occupy every point, between the obstacles on which the flanks rest, in such a manner that no intervals shall be presented through which the enemy can penetrate without being exposed to a close and powerful line of fire.

171. The artillery will be placed on those points where it can have a commanding view of the ground in advance of the position, and sweep by its fire the approaches of the enemy, both in front and flank.

172. The cavalry, posted in rear of the infantry, should occupy ground upon which it can make effective charges, to support the infantry when pressed by the enemy.

173. In posting troops on obstructed ground, care should be taken not to place them on points where they can only be idle spectators of the combat; either from the impossibility of their being approached by the enemy, or from their not being able to join the enemy at the proper moment. In like manner, those points should be avoided where, from obstacles in their rear, the safety of the troops might be compromised in case of retreat. Whenever it becomes necessary to dispute the possession of the latter class of points with the enemy, the avenues to the rear must be occupied by detachments of suitable strength, to secure the retreat of the troops in advance.

174. In order that the necessary maneuvers may be promptly executed, without confusion; and to avoid offering a mark that might attract the enemy’s fire, and occasion useless exposure; no more troops should be placed on any point than its defense may indispensably require; and whenever it becomes requisite to strengthen a weak point, by an accumulation of troops upon it, every advantage should be taken of the undulations, or other accidents of the ground, to mask them from the enemy’s fire until the moment arrives for bringing them into action.

175. The value of obstacles, as supports for the flanks, or as obstructions in the front, or rear of a position, is altogether relative; and depends on the number of troops. A very slight obstacle on a flank, which will serve to hold the enemy in check but a few minutes, may answer all the purposes of a small body of troops; by enabling them to make such changes in their dispositions as the nature of the case may call for; whereas a larger body, under like circumstances, might be overwhelmed on their flank before they could make suitable maneuvers to prevent it. A broken, obstructed country to the rear, presenting few and narrow avenues of retreat, might be fatal to a large body of troops forced to retire in the face of an enemy; whereas, to a small body, the same features of ground might present many points where strong positions could be momentarily taken up to hold the enemy in check, and force him to pursue slowly and circumspectly.

176. When it is found that the enemy is moving upon the position, the advanced-guard makes suitable dispositions to hold him in check; by occupying with its skirmishers all the obstacles in its front and flanks; when forced to retire upon the main position, these troops concentrate more and. more is they approach it, taking care not to mask the fire, or impede the action of the main-body.

177. The artillery will only open its fire when the enemy is within a destructive range; it will then concentrate its efforts against the columns of attack; not replying to the fire of the enemy’s batteries, unless it becomes urgent to do so, from their effects upon the other troops. The artillery will maintain its positions with pertinacity, as long as possible – watching its opportunities, during the different phases of the action, to support and succor the other arms; as, for example, when it becomes necessary to replace the front line of infantry by the reserve; to advance the cavalry; when the other arms are obstinately disputing a decisive point; or when the enemy abandons the attack. The great mobility of field-artillery, owing to the more recent improvements, places it in the power of this arm to act with great boldness in support of the others. The ground over which the gains may be required to move, for this purpose, should be well examined, before the attack commences, by the officer commanding the artillery; that no delays may occur in bringing them into action upon the proper point at the proper moment.

178. The main-body of the infantry should not open its fire until it can be thrown in with deadly effect. If the enemy, unchecked by the fire, still pushes forward, he must be met by a charge, either in line, or column, from the point menaced; a portion of the reserve immediately closing the interval left by the troops making the charge.

179. The reserve should not be brought into action unless its co-operation is indispensable for obtaining some decisive result; as forcing the enemy back from some important point from which the main-body has been compelled to retire; or covering the retreat of the main-body, until it can rally and form again in the rear.

180. The cavalry must be in readiness, from its position, to act promptly, either against an attempt upon the flanks of the infantry; or to profit by any faults, or disorder of the enemy. If the enemy throws forward small detachments without supporting them properly, or advances his main-line without securing his flanks, or shows symptoms of confusion in his infantry, the opportunity should not be lost by the cavalry. In all movements of the infantry, either in advancing or retiring, the cavalry should be at hand to cover it from a sudden attack.

181. If the enemy is beaten off, pursuit is made, either by the cavalry or by detachments of infantry, according to the features of the ground; whilst the main-body is promptly rallied, and placed in position, to receive the enemy should the attack be renewed.

182. The dispositions for a retreat will depend upon the circumstances under which it may be made. When the troops retire by successive lines, the greater portion of the artillery should always be in the line nearest the enemy, and between the battalions; the remainder being in the second line, ready to repulse any flank attack. The cavalry is posted in rear of the second line, either upon one, or both wings, to be in readiness for a charge at any moment.

183. When the entire force moves off together, the rear is secured by a rear-guard of the best troops, composed of one, or several arms, as the circumstances of the ground may require. The rear-guard will profit by the features of the ground to check the enemy; but will be careful not to lose time, by prolonging unnecessarily the resistance on any point; as this might bring down the main force of the enemy upon it.

184. Great circumspection should be shown in retreating through obstructed ground;in watching the enemy’s movements on the flanks; and in timely securing defiles leading to the rear; to prevent the enemy from cutting off the retreat.

185. Attack. An enemy may be made to abandon a defensive position, either by driving him from it; or by maneuvering to turn it and so force him to fall back, to secure his line of communications. In attempting the latter plan, it should not be forgotten that the assailant is, to a greater or less degree, exposed to the same danger as his adversary, who, if active and enterprising, may turn the tables on him. The celebrated battle of Rivoli, in which a portion of the Austrian force turned the flank of the French position, and was there obliged to lay down their arms,—Napoleon, using on that occasion, when these troops were discovered in his rear, one of those magical expressions, “Those are ours,” by which he so well understood how to electrify the soldier—is a remarkable example on this head. The battle of Buena-Vista, where the Mexicans, after turning the flank and gaining the rear of our troops, barely escaped a similar fate, is another; whilst that of Cerro-Gordo is as remarkable for the masterly and admirable manner in which the enemy’s position was turned and carried, although resting upon ground which was fairly deemed impracticable by him.

186. In, planning the attack of a position, attention must, in the first place, be directed to those points in which its main-strength resides, and for this reason termed the key points, the loss of which will force the assailed to retire. As the assailed will probably put forth all his efforts to maintain these points, their attack will demand corresponding exertions on the part of the assailant; and should be made only with troops of the best character.

187. In the second place, those points must be carefully examined, which, by their fire, flank the position; as an advance upon its front cannot be made without great loss and hazard of success until the assailed is dislodged from them.

188. Finally, points which are weak, either from the features of the ground, or from a faulty disposition of the troops; as approaches which are badly swept by the fire of the assailed; an exposed flank with too few troops; or a point where they are not properly placed for mutual support.

189. The main effort of the assailant is seldom directed against more than one point of the position; that one being usually selected which, if carried, will lead to the most decisive results; as for example, one of the flanks, when not resting upon any strong obstacles. But the main attack is always combined with demonstrations upon some other point; both with a view of deceiving the assailed as to the real point of attack, and to prevent him from withdrawing troops from other points to strengthen the one menaced.

190. These demonstrations, or false attacks are, in some cases, made by the advanced-guard of the assailant, after driving in that of the assailed; in others, by a special detachment. In the latter case, the detachment should seldom exceed a fourth of the entire force; and should be composed of troops of each arm; both for its own safety against any offensive movement, and to present to the assailed a likelihood of danger.

191. The advanced-guard, composed of light troops of each arm, commences the attack, by driving in the advanced posts of the assailed; keeping within supporting distance of the main-body, and occupying such points as may be necessary to cover its maneuvers, or to secure its retreat in case of failure. If a reconnaissance of the position has not been previously made, it will be effected under cover of the movements of the advanced-guard.

192. The artillery takes position where it can silence the batteries of the assailed, and prepare the way for the advance of the other troops. The infantry is usually formed in two columns for the real attack; the leading column being sometimes preceded by an advance. A part of the artillery advances either in one body, or in echelon, on the flank of the column of attack; the leading section preceding, by about a hundred paces, the -head of the column of attack. If the column of attack deploys to open its fire, the artillery moves to one of its flanks and seconds it by a fire of case shot. If the column charges with the bayonet, the advanced portion of artillery retires to the position of that in the rear; to be ready to cover the infantry by its fire, if the attack fails. The cavalry follows in the rear of the infantry; to secure its flanks from any offensive movement, and to hold the assailed in check, should he attempt a pursuit after beating off the infantry.

193. If the attack is successful, the artillery and the greater portion of the infantry are immediately formed in good order, to be in readiness for any emergency; the pursuit being left to the cavalry and some detachments of infantry. In case of failure the troops engaged fall back under cover of those in their rear; the artillery, by a well-directed fire, and the cavalry by opportune charges, holding the enemy in check, until order is re-established in the retiring troops, as a preliminary to a retreat, or to a renewal of the attack.

194. Positions in obstructed Ground. This term may be applied to localities where the ground, although level, is cut up by ditches, hedges, broken roads &c, which obstruct the free movement of troops.

195. Positions of this character are more favorable to the defensive than the offensive. As, from the nature of the case, connected movements are, for the most part, impracticable, the commander will find it difficult to direct the engagement, and must rely upon the judgment and skill of his subordinates for its successful issue.

196. The general disposition of the troops will be in dispersed order. There will be but few opportunities for the action of cavalry; and the artillery can seldom find positions to act in mass. The light cavalry and light pieces may be placed in front, wherever they can act with advantage, and support the infantry. The supports and reserves should be kept well to the rear of the troops engaged; to be ready to meet the enemy should he attempt to turn the flanks, a maneuver to which obstructed ground is frequently favorable. The heavy cavalry and heavy artillery take post to the rear, at any point which may offer a good position to cover the retreat.

197. The attack, like the defense, will be mainly conducted by the infantry, and some light pieces; the infantry, acting as skirmishers, and the artillery being employed to force any opening, that may offer, for the advance of the infantry.- Whenever the artillery gets a good position it should endeavor to keep it as long as practicable. The cavalry can effect but little; as the enemy’s, even if inferior in strength, may watch its opportunities, from behind obstacles, to make short and successful charges. The artillery not in action will occupy the roads, at points to the rear most suitable fir covering the retreat, if the attack fails.

198. In positions of a mixed character, presenting alternations of open and obstructed ground, the troops on the defensive must guard, with great care, every accessible point at which the assailant can debouche from the obstructed upon the open portions. A strong fire of heavy artillery should be brought to bear upon these points; and cavalry should be posted in places where they can be masked from the enemy’s fire, and be at hand to charge the assailant, as he attempts to debouche. These efforts should be seconded by the bayonets of the infantry, if a favorable opportunity occurs.

199. The obstructed ground to the rear must be strongly occupied, to secure the retreat; by posting light troops under the cover afforded by the skirts of woods, by ditches bordered with trees and hedges, &c.; and advantage must be taken of every small defile, to dispute the ground inch by inch.

200. In the phases of engagements in positions of this character, the defense must frequently be accommodated to the troops at hand; as in the confusion of the most orderly retreat, in such cases, it is impracticable to preserve that connection between the movements of the different arms which would be best for mutual support. If the assailant, by disconnected movements, or a disorderly pursuit, lays himself open to an attack, it should be made and pressed with vigor, or not at all.

201. In the attack of mixed positions, the supports and reserves should be kept well to the rear, whilst the troops are engaged in the obstructed portions; to guard against offensive movements on the flanks by the assailed. Those engaged should close in as the ground opens to prepare to debouche upon it in force; in which operation the infantry must covered by the cavalry and artillery. In advancing upon the obstructed ground, the way must be prepared for an attack with the bayonet, by a heavy fire of the artillery, directed particularly upon the most accessible points. Operations of this character demand extreme prudence and forethought. Every forward movement must be made with great caution; every point gained must be well secured; and its possession disputed with tenacity if the assailed attempts to repossess himself of ii. In no other way can the troops engaged be kept well in hand, and be prevented from the confusion and dangers of a hasty pursuit.

202. Positions in Forests. In occupying a forest defensively, the skirts and the openings to it, as roads, &c., must be strongly guarded by a line of skirmishers with its supports and reserves, and by artillery so placed as to sweep in flank those points which are most accessible-, as the salient portions, and the roads. The line of skirmishers, besides availing themselves of the natural covers of tile position, as trees, ravines, &c., will form abatis in front of the more accessible points; and the cannon, in like manner, should be covered by epaulments, when suitable means are at hand.

203. The main-body will take up a central position, on ground favorable to the defense; covering its flanks by marshes, or other like obstacles, strengthening, if requisite, its front by abatis; and guarding all the approaches by a suitable disposition of its heavy artillery. The points of junction of roads leading to the front should be strongly occupied, and strengthened, when practicable, by field-works.

204. The space between the skirts of the wood and the central position should be obstinately disputed; advantage being taken of any clearings that may occur, to post light pieces and cavalry in ambush near them, to drive back the assailant, as he debouches on the open ground.

205. As cavalry can only act, under such circumstances, in small detachments, the main body of it will take position to the rear, to cover the retreat of the other troops from the forest, and check the assailant in debouching from it.

206. The attack will be directed on the salient portions, and upon the entrances of the forest; first by a, heavy fire of artillery, to drive back the infantry, and force the guns of the assailed to retire. This will be followed up by a rapid attack in line, with the bayonet, on those points, whilst demonstrations are made against the others occupied by the assailed. If the attack with the bayonet succeeds, the troops must secure the points seized before pushing forward in pursuit; placing some cannon and troops at the most suitable points, to cover the retreat, should the assailed make a strong offensive movement.

207. The pursuit should be made firmly but cautiously; the skirmishers leading and rooting out the assailed from every strong cover; some field-pieces, and a column of infantry, each secured by skirmishers on their flanks, following upon the main road, with a detachment of cavalry well to the rear, but within supporting distance, to act according to the emergency.

208. If the assailed makes a firm stand at his central position, an attack upon his front will not only be bloody but of doubtful success; an attempt should therefore be made to turn his flanks, he is occupied in front by demonstrations and false attacks. If the assailed retires, the pursuit will be made by some light pieces followed by the infantry and cavalry; the different arms being employed according to the varying circumstances of the ground.

209. Positions in Mountains. The best and only safe system of defense in mountainous positions is to occupy, with the main-body, a central point, at which the principal passes meet and be always in a state of readiness to act offensively against the enemy, on whatever point he may advance; throwing forward strong detachments in the principal passes to observe the enemy, and offer a vigorous resistance, in order to force him to develop his plan of attack. So soon as it is ascertained on what point the principal force of the enemy is concentrated, the main-body will advance, from the central position, to a point where it will be secure from a flank attack, to act offensively. The detachments on the other passes will act on the flanks of the enemy, by crossroads, if they can do so, or will try to fall on his rear.

210. When circumstances constrain to a passive defense, a position must be taken up either across, or along the valley, which will best secure the flanks, and cover the line of communication.

211. The attack in mountainous positions is conducted on the same principles as the defense. The assailed must be threatened on every point; by throwing columns into the several passes;, whilst the main-body advances along one of the principal lines. If the assailed maintains a strict defensive, the several columns unite and make the attack; if he assumes the offensive, the principal columns must be reinforced, and an attempt be made to throw detachments on his flanks and rear, to force him to fall back. The flanks of the troops in column, advancing in the valleys, must be covered by detachments of skirmishers on the heights.

212. The attack will be made mainly by the infantry, as skirmishers. A strong line of fire must be maintained with great pertinacity; the supports must be kept well to the rear; the. reserve and main-body holding the points of junction of the roads leading to the front, and not advancing until the engagement is well under way.

Great prudence must be shown in advancing; as the troops engaged are liable at any moment to an attack on their flank. If the assailed attempts this maneuver, the line of skirmishers must hold on pertinaciously to the ground gained, whilst the supports display and keep the enemy in check, until the reserves can be brought up to -repel the attack with the bayonet. As the line of skirmishers force back the assailed, the main-body follows in column along the valley; its flanks being secured by skirmishers on the heights. If opposed by the as-sailed, the main-body must attack with vigor, to carry its point promptly; as those engaged in- front have no chance of being relieved.

213. There is here seldom any field of action for cavalry; the main portion of this force will therefore be kept to the rear; occupying the points of junction of the passes. Small detachments of dragoons may occasionally do good service in front; making charges, or fighting on foot, as the opportunity offers.

214. The artillery can seldom find positions on the roads. A few light pieces, which can be placed in position on the heights and be well served, may frequently produce very decisive results. When it is necessary to open a way, for the main-body to advance, at points of peculiar strength, it should be done by the heaviest pieces. The horse-artillery will usually be attached to the troops charged with making a demonstration on the flanks of the enemy’s position, through the secondary passes.

215. As the assailed will probably obstruct the passes by abatis, or other obstacles, a detachment of engineer troops should accompany each column, being kept always at hand to clear away the obstructions.

216. Positions near Rivers. Positions may be selected near rivers either for the defensive, to prevent an enemy from passing; or for the offensive, to force a passage.

217. A position for guarding a river should be selected at some central point, from which the troops can be rapidly marched to oppose the enemy wherever he may attempt to cross. Small posts are established along the course of the river, at the most suitable points for observing the enemy; and communicating to the rear intelligence of his movements. So soon as it is known that a decided attempt is to be made at any point, the cavalry, with some batteries of horse-artillery, will move to oppose it. If, on reaching the point, it is found that the enemy has succeeded in throwing over a portion of its forces, they must be vigorously attacked, by successive charges of cavalry, and by a persevering fire of the artillery. If the ground is obstructed, so that the cavalry cannot charge, the dragoons should dismount and act as skirmishers. Positions should be selected by the artillery, where it can take that of the enemy, on the opposite bank, in flank; the object being to silence it, or to draw off its fire, to enable the cavalry to act. Everything here depends on lengthening the affair; and preventing the enemy from reinforcing the troops that have passed, until the main-body can arrive from the central position, to support the cavalry and artillery engaged.

218. The passage of a river in the face of an enemy is an operation of extreme difficulty; and every means should therefore be employed to deceive the enemy, and draw off Ms attention from the point selected for the passage. The bridge-train and other requisites being in a state of readiness, the night-time is selected as most favorable to a successful issue. The point, selected to pass a river in the face of an enemy, should combine several properties, as a position; to give the assailant a decided advantage over the assailed. The river at this point should be narrow, so that the bridge may be rapidly constructed; the banks should form a bend towards the assailant, to enable him to plant his batteries in a position to concentrate their fire on that part of the ground, on the opposite bank, where the troops must form; care being taken that these batteries are not exposed to an enfilading fire from those of the assailed, within the proper range for this fire; the ground near the landing place, on in order that the troops, passed over in boats before the bridge is ready, may not be exposed to the artillery and cavalry of the assailed, and may be enabled to maintain their position until reinforced by the main-body. If there are islands, near the point of landing, from which a fire of artillery and infantry can be brought to bear on the assailed, they should be occupied by infantry, and some filed-pieces; particularly if they are wooded, or offer other covers.

219. in moving upon the point, silence and perfect order should be preserved throughout. Batteries of the heaviest guns are placed at the most suitable points, to bring a converging fire to bear upon the approaches to the landing on the opposite shore. Light troops are thrown over in boats, to occupy the ground in advance of the landing which troops, if discovered by the advanced posts of the enemy, should be rapidly reinforced. So soon as the bridge is ready; all advanced-guard, composed of troops of all arms, will pass and take position to cover the formation of the main-body. The advanced-guard will mainly keep on the defensive, acting with great prudence, not to offer any advantage to the enemy; its task being to gain time for the rest of the forces to pass.

220. The order in which the main-body should pass must be regulated by the character of the ground, and the resistance offered by the enemy. Usually a portion of the heavy guns follow the advanced-guard, and take position to check the enemy; the main-body of the cavalry with its batteries of horse-artillery passing last. In other cases, it may be best to throw over the cavalry and horse-artillery before the other troops.

221. The task, imposed upon the batteries, of covering the passage, is of the greatest moment. Careful attention should be given to the management of their fire; directing it, in all cases, upon that portion of the enemy’s force whose presence is most threatening.

222. A retreat across a river, when pressed by the enemy, is of all operations the most difficult; and requires every auxiliary means to save the retreating force from destruction. The point selected for the passage should have the same requisites as one for the offensive; and its natural strength should be increased by field works; in order that the enemy may be kept from pressing too hotly upon the rear of the troops that pass the last. In a retreat of this character, all the usual stratagems for deceiving an enemy must be resorted to before commencing the movement;- so that time sufficient may be gained for making the necessary dispositions to secure the point of passage, as well as to gain a march, or two, in advance. The heavy artillery should be dispatched at an early moment to the rear, to take a position on the opposite shore, for covering the passage. The rest of the force, covered by a strong rear-guard, formed of the best troops, will effect their passage gone rally in an inverse order to that followed in one for the offensive. One of the worst dangers to be guarded against is the confusion caused by hurry. To avoid this, the arrangements for the march of the different bodies should be made with the greatest care; so that each may reach, at the proper moment, the point of passage.

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