In this important crisis of battles, theory becomes an uncertain guide; for it is then unequal to the emergency, and can never compare in value with a natural talent for war, nor be a sufficient substitute for that intuitive _coup-d'oeil_ imparted by experience in battles to a general of tried bravery and coolness. The simultaneous employment of the largest number of troops of all arms combined, except a small reserve of each which should be always held in hand,[27] will, therefore, at the critical moment of the battle, be the problem which every skillful general will attempt to solve and to which he should give his whole attention. This critical moment is usually when the first line of the parties is broken, and all the efforts of both contestants are put forth,--on the one side to complete the victory, on the other to wrest it from the enemy. It is scarcely necessary to say that, to make this decisive blow more certain and effectual, a simultaneous attack upon the enemy's flank would be very advantageous. 13. In the defensive the fire of musketry can be much more effectively used than in the offensive, since when a position is to be carried it can be accomplished only by moving upon it, and marching and firing at the same time can be done only by troops as skirmishers, being an impossibility for the principal masses. The object of the defense being to break and throw into confusion the troops advancing to the attack, the fire of artillery and musketry will be the natural defensive means of the first line, and when the enemy presses too closely the columns of the second line and part of the cavalry must be launched against him. There will then be a strong probability of his repulse. FOOTNOTES: [Footnote 24: In every battle one party must be the assailant and the other assailed. Every battle is hence offensive for one party and defensive for the other.] [Footnote 25: The letter A in this and other figures of the twelve orders indicates the defensive army, and B the offensive. The armies are represented each in a single line, in order not to complicate the figures too much; but it should be observed that every order of battle ought to be in two lines, whether the troops are deployed in columns of attack, in squares, or checkerwise.] [Footnote 26: An attack upon the two extremities might succeed also in some cases, either when the force was strong enough to try it, or the enemy was unable to weaken his center to support the wings. As a rule, a false attack to engage the center, and a strong attack against one extremity, would be the best method to use against such a line.]