The surprise of the enemy, by placing superior forces in position at certain points, has again a great resemblance to the analogous case in tactics. Were the defensive compelled to distribute his forces upon several points of approach to his theatre of war, then the offensive would have plainly the advantage of being able to fall upon one point with all his weight. But here also, the new art of acting on the defensive by a different mode of proceeding has imperceptibly brought about new principles. If the defensive side does not apprehend that the enemy, by making use of an undefended road, will throw himself upon some important magazine or depôt, or on some unprepared fortification, or on the capital itself.—and if he is not reduced to the alternative of opposing the enemy on the road he has chosen, or of having his retreat cut off, then there are no peremptory grounds for dividing his forces; for if the offensive chooses a different road from that on which the defensive is to be found, then some days later the latter can march against his opponent with his whole force upon the road he has chosen; besides, he may at the same time, in most cases, rest satisfied that the offensive will do him the honour to seek him out.—If the offensive is obliged to advance with his forces divided, which is often unavoidable on account of subsistence, then plainly the defensive has the advantage on his side of being able to fall in force upon a fraction of the enemy. Attacks in flank and rear, which in strategy mean on the sides and reverse of the theatre of war, are of a very different nature to attacks so called in tactics. 1st. There is no bringing the enemy under two fires, because we cannot fire from one end of a theatre of war to the other. 2nd. The apprehension of losing the line of retreat is very much less, for the spaces in strategy are so great that they cannot be barred as in tactics. 3rd. In strategy, on account of the extent of space embraced, the efficacy of interior, that is of shorter lines, is much greater, and this forms a great safeguard against attacks from several directions. 4th. A new principle makes its appearance in the sensibility, which is felt as to lines of communication, that is in the effect which is produced by merely interrupting them.