Infantry is the decisive arm. Other arms are exclusively there to smooth their road to victory, and support their action directly or indirectly. This relation must not be merely theoretical; the needs of the infantry must ultimately determine the importance of all other fighting instruments in the whole army. If we make this idea the basis of our argument, the following is the result. Infantry has gained enormously in defensive power owing to modern weapons. The attack requires, therefore, a far greater superiority than ever before. In addition to this, the breadth of front in action has greatly increased in consequence of the former close tactical formations having been broken up through the increase of fire. This refers only to the separate detachment, and does not justify the conclusion that in the future fewer troops will cover the same spaces as before. This assumption applies at the most to defence, and then only in a limited sense. In attack the opposite will probably be the case. The troops must therefore be placed more deeply _en échelon _than in the last wars. Now, the average breadth of the front in attack must regulate the allotment of artillery to infantry. No definite proportion can be settled; but if the theoretical calculation be compared with the experiences of the last wars, conclusions may be obtained which will most probably prove appropriate. No more than this can be expected in the domain of military science. If we agree to the above-mentioned proportion of breadth and depth in an infantry attack, we shall be driven to insist on a reduction of artillery as compared with the past; but should we think that modern artillery helps the attack, especially by indirect fire, we must advocate, from the standpoint of offensive warfare, an increase of the artillery. Actual war experiences alone can find the true middle path between these two extremes. If the frontal development of the artillery of a modern army corps, or, better still, two divisions, be regarded from the point of view that the guns cannot advance in connected line, but that only the specially adapted parts of the field can be used for artillery development, the conclusion is certain that by such frontal extension the infantry is reduced to a covering line for the artillery. In forming this opinion we must not assume the normal strength of the infantry, but take into account that the strength of the infantry in war rapidly melts away. If we estimate the companies on the average at two-thirds of their proper strength, we shall be above rather than below the real figures. Such infantry strength will, of course, be sufficient to defend the position taken up by the artillery, but it is hardly enough to carry out, in that section of the field, a decisive attack, which, under present conditions, requires greater numbers and depth than before.