There is absolutely no doubt that wherever the Germans retreat, they will endeavour to accumulate obstacles behind them as they did on the Somme and the Aisne. The question of the advance of the different artilleries must therefore be very carefully considered. Means must be found to ensure it, while keeping within the immediate reach of each battery the requisite munition supply. America, however great her participation in the war, will never be able to mobilize more than a small part of her immense population. Unlike France, she will not be forced to suspend the activities of ordinary industrial and commercial life. Assisted by technicians, she will succeed in training all the special troops required and in supplying them fully with material. She will even be able to lend some of them to France, who, having mobilized all her fencible men for service at the front or rear, experiences great difficulty in recruiting the technical troops she needs. The problem of the rapid advance of the artillery is to be solved by increasing the road-making facilities. Whatever the difficulties encountered and the obstacles created by the enemy, we must be able to make, with the least possible loss of time, large and solid roads in sufficient number, and to repair or build entirely new lines of railroads of all gauges. WITHDRAWAL. We must always foresee the possibility of a defeat, prepare everything to lessen it, and leave as few guns as possible in the hands of the enemy. This problem is easier to solve than that of an advance towards the enemy, and in order to be able to withdraw the various artilleries rapidly, it will be sufficient, when preparing the attack, to have foreseen the number of roads and tracks necessary to remove the batteries from the front. These roads and railway lines have to be constantly kept in order by special gangs, and the holes made by shells must be immediately filled up. In fact we shall see that the perfect repair of all these ways of communication is intimately connected with the supply of munitions. =6. Conclusion.= From the mere general outlines we have just given concerning the use and mission of the artillery, we may draw the following conclusion: Till the end of the war it will be necessary to constantly increase the manufacture of guns of all sizes, especially those of the largest calibres, and to accumulate a reserve of ammunition far beyond the actual needs. The adversary that will have succeeded in silencing the opposing artillery will be sure of victory, and will obtain it without the enormous losses in human life that all combatants have sustained since the beginning of the war. These losses, it may be remarked in passing, have been considerably reduced of late by the employment of more scientific methods of fighting.