Artillery and machine-guns must come into action in such a way that they will be able to combine with the firing-line in concentrating an overwhelming fire against the decisive points of attack. The guns will generally be able to come into action under cover, and to fire indirect against the enemy in position. They will only engage the enemy's artillery if the latter shows itself in open or half-covered positions with the object of turning its fire on the advancing attack. Otherwise the fire of the artillery will be directed against the enemy's firing-line or any mounted detachments that are visible. It is of importance that a sufficient quantity of ammunition should be brought up, and that it should not be wasted by random fire against invisible targets. The orders for the fight must be issued with great care and clearness, for, once the battle is begun, it will not generally be possible to make changes of disposition. The difficulty, also, of changing the front of the fighting-line increases in proportion to the size of the units employed. It is therefore of the highest importance not only to determine the front of attack before the commencement of a fight, but also to give a clear order allotting a definite task to each unit, which should, when possible, be made known to all the troops. Only if this is achieved will they be able to act independently according to the spirit of the orders. When all preparatory dispositions have been made, the attack should, if possible, be commenced simultaneously, unless circumstances demand that some detachments take up the fire fight before the others are ready to co-operate. From the moment that the attack is commenced, but one thought should inspire the troops: "_Forward against the enemy, cost what it may_." Pressing continually to the front, each must endeavour to surpass his neighbour. Should further advance be impossible without reinforcements, the ground won must be maintained at all costs, even against hostile counter-attack. The strength of the first deployment of the firing-line must depend on circumstances. In any case the whole breadth of that part of the enemy's front must be simultaneously engaged which is able to direct its fire against the attack, as otherwise the latter will be exposed to flanking or cross-fire. If the ground allows of a covered approach to within effective range, a sufficiently thick firing-line should be established at once. On the other hand, where cover is scarce, it will sometimes be advisable, when sufficient time can be spared, to deploy at first only a loose, irregular firing-line, which will offer a difficult target to the enemy, or to remain at first under cover and gradually to strengthen the firing-line in the same way until it attains the strength necessary to commence the attack. In the further advance, supports must follow all the firing-lines, to make good losses, keep up the ammunition supply, and to put new moral strength into the fighting-line.