"The Art of War, in order to arrive at its aim (which is to impose its will upon the enemy), knows but one means, the destruction of the adversary's organised forces. So we arrive at the battle, the only argument of war, the only proper end that may be given to strategical operations, and we begin by establishing the fact that to accomplish the aim of war the battle cannot be purely defensive. The results of a defensive battle are exclusively negative; it may check the enemy in his march; it may prevent him from achieving his immediate aim; but it never leads to his destruction, and so is powerless to achieve the wished-for victory. Therefore, every defensive battle must terminate with an offensive action or there will be no result" (Marshal Foch). CHARACTERISTICS OF THE BATTLE.--No two battles are precisely similar, but there are certain characteristics common to every battle. In the first place, the issue is almost always uncertain, for events which no human sagacity could provide against may occur to defeat the wisest plans. The best chances, therefore, are on the side of the commander who is provided with sufficient means to achieve his object, who forms his plans with the greatest sagacity, and executes them with the greatest ability. Decisive success has followed the combinations of great commanders, and in the long run victory pays homage to knowledge of the principles which underlie the art of war. {25} In the second place, the human factor always plays its part in battle. Troops lacking in discipline are liable to panic in face of a sudden disaster, and even the best troops are liable to become unsteady if their flank is gained. In the third place, a comparatively small body of fresh troops thrown into action at the right moment against greater numbers, if the latter are exhausted by fighting, may achieve a success out of all proportion to their numbers. For this reason a prudent commander will endeavour to retain under his control some portion of his reserves, to be thrown in after his adversary has exhausted his own reserve power. To be superior at the point of attack is the Art of Warfare in a nutshell, and for this reason attacks on separate points of a position must be properly synchronised to be effective. The unbeaten enemy will otherwise possess a mobile reserve with which to reinforce threatened points. The attacks must be so timed that he throws them in piecemeal or fails to reach the point mainly threatened.