1. A large river which crosses the direction of the attack is always very inconvenient for the assailant: for when he has crossed it he is generally limited to one point of passage, and, therefore, unless he remains close to the river he becomes very much hampered in his movements. Whether he meditates bringing on a decisive battle after crossing, or may expect the enemy to attack him, he exposes himself to great danger; therefore, without a decided superiority, both in moral and physical force, a general will not place himself in such a position.