In the case of other defiles, the dispositions are much the same, only that, in general, we have no occasion to be detained in preparing loads. Almost every thing, therefore, must depend upon our having secured the debouche; which must be done by throwing forward a corps to take possession of some tenable place, or good position, at the outlet of the defile. If N is has been effected, we have gained every thing. But the longer the defile, and the more difficult the roads through it, the less easy will it be to effect this ob ject. Hence, the passage of this description of defiles is considered as much more difficult than that of rivers ; especially if the enemy has fortified the passes, be cause these must first be forced, and then the debouche secured.
In opposing the passage of a liver, it is presupposed that the enemy can find no points at which he can effect the passage by force, or, at least, that he has not the superiority necessary to enable him to accomplish that object. The following are the general dispositions for preventing the passage of a river. 1. \Ve must break down all the bridges in the neighbourhood, and destroy all the fords, and secure all the boats and vessels above and below, as far as we can reach. Should any bridge be left standing, it must be sufficiently secured by a strong entrenchment, or tete•de-pont. 2. \Ve must all those posts from whence we can obtain in telligence of the enemy's movements, and at the same time obstruct his passage. 3. If we have sufficient time and means, we should throw up entrenchments at all important points which command the passage, in order to occupy them as soon as we learn that the enemy in tends to pass at that place. These entrenchments must be so situated, that if the enemy had suddenly occupied them, we should still be able to drive him out. After these preparatory dispositions, we may adopt one of, two plans. In the first place, we may take a position on the river, opposite to the enemy, and follow all his motions with the whole or a part of the al my, in order to oppose his passage at every point. Or, secondly, we may take a position with the whole army, not quite close to the river, but at a distance to be determined by its course, which will enable us to arrive at any point where the enemy might attempt to pass, before he can accomplish his object. The country un and about the river must he strongly occupied with posts, in order to obtain early intelligence of every one of the enemy's motions. As
soon as we are assured that the enemy is seriously at tempting the passage at any particular point, we must march thither, and attack all that have already crossed, or destroy the bridges, or at least prevent him from per severing in the enterprise, if we can do nothing more. We must beware, however, of allowing ourselves to be drawn too rapidly to any one point, as the enemy might then really effect the passage at some other place. So long as we are in a state of uncertainty, IN e should merely hold ourselves in readiness to march, or send a corps in advance, for the purpose of obstructing the opera tions of the enemy. The advantage of this method of defending a river consists in this, that the army is not separated in consequence of the passage of the enemy, nor receives any serious blow, nor is forced to expose a great part of its parallel, in order to unite at a great distance behind. There is still a third method of de fending the passage of a river, but which can only be employed by an army which is nearly equal to that of the enemy, when the course of the river does not admit of our adopting the second method, in consequence of the river presenting a convex bend to the defending party. This method is, to pass the river ourselves, to take up a strong position close to the enemy, and then hold ourselves in readiness to beat him while he is en gaged in the passage. Bold as this method may appear, there is no doubt that it may be attended with singular success under proper precautions. In all enterprises of this nature, indeed, especially where troops can only be brought successively into action, much will always de pend upon activity, boldness, and decision ; and the fortunate issue will generally be determined by the first attack. When the leading columns have crossed a bridge, or penetrated through a defile, and have maintained their ground until the army is come up and enabled to support them, the success of the event is determined. Hence, it is always of essential importance to prevent the deployment of the leading columns ; not a moment must be lost in charging them ; the least hesitation may produce irretrievable ruin. The attack being resolved upon, it must be made with impetuosity, because, should it be repulsed, there can be little hope of making a second more successful.