If we cannot attack the enemy otherwise than in a state of preparation, we must endeavour to penetrate into the country in spite of his army. For this purpose, it will be necessary for us to force his army at that point, which will lead us most safely and immediately towards the object we have in view. This may he ef fected, I. By a diversion, that is, by causing an attack to be made in some other quarter, so as to make him draw off his troops, or weaken his army at that point where we w.sh to penetrate. This method is generally adopt ed, when the enemy has taken up a strong position which covers the whole country ; or when we wish to undertake a seige, but are prevented by the strength and advantageous position of the army opposed to us. In order to render this method effectual, however, it is necessary that we should have a sufficient superiority of force, and that our diversion should threaten great dan ger to the enemy. 2. By intercepting and cutting off his supplies. This may be done, by establishing posts on the rivers or passes, by which he receives his provi sions ; or by constant attacks on his convoys and forag incr parties, which requires a great superiority in light troops, especially cavalry. 3. By means of detachments, which is a species of diversion. 4. By manoeuvring, that is, by marching and countermarching in such a manner as to threaten the enemy in some other quar ter, and, while he makes corresponding movements in order to oppose us, to seize the occasion of his weaken ing the point at which we wish to force him. 5. By bringing the enemy' to a battle, which is the most sim ple of all methods, But as a battle is, in many respects, more liable to chance than any other military enter prise, and the enemy will naturally always endeavour to take up a strong position, a prudent general will rather try every other means, if possible, unless he per ceives the probability of obtaining extraordinary advan tages from fighting.
To lay down a plan of operations for a defensive war, and to carry it into execution, are matters of much more difficulty. A skilful general, therefore, will al ways endeavour to seize some opportunity of converting a defensive into an offensive war, by striking such a blow as will give him the superiority over the enemy. As in a defensive war the difficulty consists in our be ing generally obliged to regulate our movements ac cording to those of the enemy, of which we cannot al ways obtain sufficiently early intelligence, it is necessary, in laying down a plan of operations for a defensive war, to anticipate the probable undertakings of the enemy, according to the nature of the country, and to take pro per measures for opposing them. If, for example, the defence of a country depends upon fortresses, these must be previously supplied with all necessaries, and the positions must be determined from which they are to receive succour, when threatened. If it depends up on the defence of a river, or other defile, the positions necessary for its defence, as well as the means of de fending it, must be previously taken. When the de fence rests upon the army itself, posts and tenable places must be prepared for it ; and much prudence will be required in selecting such as are most advanta geous ; otherwise the covering army must be made sufficiently strong as to enable it, under a skilful com mander, to assume an offensive attitude. In a defensive war, the following general rules are also to be observ ed: 1. We must be in a situation to take the field in such good time as to oppose any enterprise on the part of the enemy. 2. Every precaution must be taken, in
order that the army may find supplies at every point to which they may be called by the enemy's move ments, which is often a matter of great difficulty. Last ly, We have already observed, that a prudent comman der must avail himself of every good opportunity to convert a defensive into an offensive war ; the various possibilities of such an event, therefore, must be antici pated, and all measures taken to make the most of such an opportunity when it occurs.
An army is drawn together, either for the first time, at the commencement of a war, or during a war, at the opening of a campaign, with the view of acting either offensively or defensively.
If it be intended to surprise the enemy, at the com mencement of an offensive war, the troops are marched rapidly out of their quarters towards the appointed place of rendezvous. This place may be either on our own frontier, in order to penetrate, with our combine° force, into the enemy's country ; or in the enemy's ter ritory itself, in which case the troops march into it at once in columns, or in divisions following each other. The first plan is generally adopted, when the enemy is not strong enough to oppose our combined force, but might annoy particular portions of the army. In other cases, the latter plan is generally preferred.
If, at the commencement of an offensive war, a sur prise is impossible, the troops are drawn together gra dually, for their convenience, to accustom them by de grees to the hardships of war, and to enable us to com plete our measures for the campaign. It is often ne cessary, too, to conceal the real point of attack ; and for this purpose the army is drawn together in several separate corps, which can be united at any time ; or a considerable extent is given them in their quarters, in order to unite them on any part of the line at pleasure. In these measures, we must be guided very much by a skilful calculation of the distance of places, the nature of the roads between them, and the capability of the troops in performing marches.
In drawing an army together for a defensive war, we must be guided by the means we possess for con ducting it, and by other peculiar circumstances. 1. If the post to be defended has been determined upon, we may then advance towards it, strengthen it, if necessa ry, by the labour of the troops, or of peasants, and cause it to be occupied by a detached corps ; or it may be occupied by the whole army, whether the enemy's army be united or not. 2. The choice of the post de pends upon the measures of the enemy. In that case we must follow his movements, and keep our quarters as much extended as is consistent with the possibility of concentrating. whenever the enemy's motions render it necessary, and with the safety of the army. if the defence of the country depends upon fortresses, the ar my may be drawn together in the following manner : I. A post is chosen, from which the investment of each fortress may be prevented, or from whence, at least, it may be succoured. In this case, however, it is necessary that the army be in a condition to cope with that of the enemy. 2. The army may be divided into several corps, occupying strong camps under the can non of the fortresses, in order to prevent the enemy from besieging them. In such a case, the cavalry is fre quently formed into a separate corps, and endeavour, by constant enterprises, to put every kind of obstacle in the way of the enemy.