here we have the containing or secondary attack, and the main or reserve force which decides the battle of to-day — a most striking instance of the continuity of military principles.
Considerable space is devoted to the influence of ground on war. The passage of defiles and rivers is still conducted in the same way. The many large rivers of China naturally affected military operations; and, among other axioms, it is laid down that the passage of a river should not be disputed, as the enemy will probably give up the attempt, and make the passage untouched at some other point, but that he should be attacked when half his force is across the stream. Again, an army should not encamp on a river below the enemy, as it is thereby liable to be inundated, or to have its water poisoned; or the enemy may come down stream and make a sudden attack.
While both writers were professional soldiers, they show a fine disinterestedness by repeatedly pointing out that even
