But all the roads which lead from the point occupied by an army to its sources of existence and power, are not on that account necessarily lines of communication for that army. They may no doubt be used for that purpose, and may be considered as supplementary of the system of communication, but that system is confined to the lines regularly prepared for the purpose. Only those roads on which magazines, hospitals, stations, posts for despatches and letters are organised under commandants with police and garrisons, can be looked upon as real lines of communication. But here a very important difference between our own and the enemy’s army makes its appearance, one which is often overlooked. An army, even in its own country, has its prepared lines of communication, but it is not completely limited to them, and can in case of need change its line, taking some other which presents itself, for it is every where at home, has officials in authority, and the friendly feeling of the people. Therefore, although other roads may not be as good as those at first selected there is nothing to prevent their being used, and the use of them is not to be regarded as _impossible_ in case the army is turned and obliged to change its front. An army in an enemy’s country on the contrary can as a rule only look upon those roads as lines of communication upon which it has advanced; and hence arises through small and almost invisible causes a great difference in operating. The army in the enemy’s country takes under its protection the organisation which, as it advances, it necessarily introduces to form its lines of communication; and in general, inasmuch as terror, and the presence of an enemy’s army in the country invests these measures in the eyes of the inhabitants with all the weight of unalterable necessity, the inhabitants may even be brought to regard them as an alleviation of the evils inseparable from war. Small garrisons left behind in different places support and maintain this system. But if these commissaries, commandants of stations, police, fieldposts, and the rest of the apparatus of administration, were sent to some distant road upon which the army had not been seen, the inhabitants then would look upon such measures as a burden which they would gladly get rid of, and if the most complete defeats and catastrophes had not previously spread terror throughout the land, the probability is that these functionaries would be treated as enemies, and driven away with very rough usage. Therefore in the first place it would be necessary to establish garrisons to subjugate the new line, and these garrisons would require to be of more than ordinary strength, and still there would always be a danger of the inhabitants rising and attempting to overpower them. In short, an army marching into an enemy’s country is destitute of the mechanism through which obedience is rendered; it has to institute its officials into their places, which