If the enemy artillery is left free, it will shell our trenches and approaches, causing casualties and confusion and thus interfering with the formation for the attack. The location of hostile batteries is effected by aerial reconnaissance. Another task of the artillery is to prevent the hostile reserves from coming up to reinforce their firing lines. These reserves will be located back in the second line until their presence is required at the front. As long as the artillery preparation continues they remain in the shelters, but as soon as it ceases they man the trenches. The artillery must therefore extend its fire to the second line and continue it while the first line is being rushed. Back of the second position the enemy holds strong reserves. The entrance of these into action must be prevented. This is accomplished by extending the curtain of fire still further to the rear. The supporting points must receive a lion’s share of attention for, bristling with machine guns and trench mortars, they are the really dangerous elements to the infantry attack after it passes the first line trenches. The weapon which inflicts the greatest losses on the assaulting infantry is the machine gun, which appears suddenly out of the ground and lays low whole units. By a careful reconnaissance these machine-gun positions are ferreted out and every possible means are taken to effect their destruction. The effectiveness of the artillery preparation depends simply upon superiority of guns and munitions. In this respect we now possess a great advantage, for the state of our munition supply is such that our artillery may fire several shells to one of the enemy. This is what established the superiority. [Sidenote: Organization of Infantry Attack] The organization of the attacking infantry corresponds in a general way to the organization of the position being attacked. A first line of assault is organized. Its mission is the capture of the enemy’s first line trenches. A second line follows, having for its mission the assault and capture of the second line trenches. A separate organization of these two lines is necessary for the reason that the first attacking line is generally so disorganized in the fighting that it no longer possesses the cohesion necessary to carry it through to the second line. It has been found necessary to launch a comparatively fresh and intact force against it. As the first position is organized into several separate lines of defense, so also is the first attacking line organized and launched in two or more waves, those in rear being in the nature of reinforcements to those in front. [Sidenote: Objectives] Each unit of the attacking line is assigned a distinct objective. Certain units are given the mission of attacking the supporting points to prevent their enfilading the units advancing through the intervals between them.