CHAPTER VII.
Advanced Guard and Out-Posts
These two bodies belong to that class of subjects into which both the tactical and strategic threads run simultaneously. On the one hand we must reckon them amongst those provisions which give form to the battle and ensure the execution of tactical plans; on the other hand, they frequently lead to independent combats, and on account of their position, more or less distant from the main body, they are to be regarded as links in the strategic chain, and it is this very feature which obliges us to supplement the preceding chapter by devoting a few moments to their consideration.
Every body of troops, when not completely in readiness for battle, requires an advanced guard to learn the approach of the enemy, and to gain further particulars respecting his force before he comes in sight, for the range of vision, as a rule, does not go much beyond the range of firearms. But what sort of man would he be who could not see farther than his arms can reach! The foreposts are the eyes of the army, as we have already said. The want of them, however, is not always equally great; it has its degrees. The strength of armies and the extent of ground they cover, time, place, contingencies, the method of making war, even chance, are all points which have an influence in the matter; and, therefore, we cannot wonder that military history, instead of furnishing any definite and simple outlines of the method of using advanced guards and outposts, only presents the subject in a kind of chaos of examples of the most diversified nature.
Sometimes we see the security of an army intrusted to a corps regularly appointed to the duty of advanced guard; at another time a long line of separate outposts; sometimes both these arrangements co-exist, sometimes neither one nor the other; at one time there is only one advanced guard in common for the whole of the advancing columns; at another time, each column has its own advanced guard. We shall endeavour to get a clear idea of what the subject really is, and then see whether we can arrive at some principles capable of application.
If the troops are on the march, a detachment of more or less strength forms its van or advanced guard, and in case of the movement of the army being reversed, this same detachment will form the rearguard. If the troops are in cantonments or camp, an extended line of weak posts, forms the vanguard, the outposts. It is essentially in the nature of things, that, when the army is halted, a greater extent of space can and must be watched than when the army is in motion, and therefore in the one case the conception of a chain of posts, in the other that of a concentrated corps arises of itself.
The actual strength of an advanced guard, as well as of outposts, ranges from a considerable corps, composed of an organisation of all three arms, to a regiment of hussars, and from a strongly entrenched defensive line, occupied by portions of troops from each arm of the service, to mere outlying pickets, and their supports detached from the camp. The services assigned to such vanguards range also from those of mere observation to an offer of opposition or resistance to the enemy, and this opposition may not only be to give the main body of the army the time which it requires to prepare for battle, but also to make the enemy develop his plans, and intentions, which consequently makes the observation far more important.
According as more or less time is required to be gained, according as the opposition to be offered is calculated upon and intended to meet the special measures of the enemy, so accordingly must the strength of the advanced guard and outposts be proportioned.
Frederick the Great, a general above all others ever ready for battle, and who almost directed his army in battle by word of command, never required strong outposts. We see him therefore constantly encamping close under the eyes of the enemy, without any great apparatus of outposts, relying for his security, at one place on a hussar regiment, at another on a light battalion, or perhaps on the pickets, and supports furnished from the camp. On the march, a few thousand horse, generally furnished by the cavalry on the flanks of the first line, formed his advanced guard, and at the end of the march rejoined the main body. He very seldom had any corps permanently employed as advanced guard.
When it is the intention of a small army, by using the whole weight of its mass with great vigour and activity, to make the enemy feel the effect of its superior discipline and the greater resolution of its commander, then almost every thing must be done sous la barbe de l’ennemi, in the same way as Frederick the Great did when opposed to Daun. A system of holding back from the enemy, and a very formal, and extensive system of outposts would neutralise all the advantages of the above kind of superiority. The circumstance that an error of another kind, and the carrying out Frederick’s system too far, may lead to a battle of Hochkirch, is no argument against this method of acting; we should rather say, that as there was only one battle of Hochkirch in all the Silesian war, we ought to recognise in this system a proof of the King’s consummate ability.
Napoleon, however, who commanded an army not deficient in discipline and firmness, and who did not want for resolution himself, never moved without a strong advanced guard. There are two reasons for this.