2. =Fire on Communication Routes, Depots, etc.= This fire, besides its destructive effect upon the enemy’s position, hinders the arrival of reinforcing troops, material, ammunition, and food. The shelling of distant roads, depots, and bivouacs is carried out by batteries of long-range guns. The fire on the nearest communications, such as interior supply routes, entrances of boyaux, kitchen emplacements, etc., is executed by light batteries of the divisional artillery. 3. =Destructive Fire.= Before the attack, the whole of the enemy’s position is submitted to methodical and violent artillery fire for the purpose of destroying: Obstacles which may hinder the advance of the assaulting column: accessory defenses, such as barbed wire entanglements. Elements of the defense, such as strong points, machine gun emplacements, observatories, depots, shelters, and dugouts. Each different kind of target calls for a certain number of rounds of a particular caliber. These calculations of the different numbers of rounds are the results of experience and are set down in tables for the information of the sector commander. The time, therefore, necessary for a proper preparation for the attack is a function of the number and strength of targets. The artillery preparation may last from one to twenty days, but it must continue until the elements of the hostile position are sufficiently destroyed to assure a successful attack. Before an offensive, there is placed at the disposal of the attacking divisions, besides their regular divisional artillery, a special allotment of batteries. The different calibers of guns are used according to the nature of the target. The largest calibers are employed against the strongest elements of the organization: nests of resistance, strong points, and deep dugouts. Light artillery is used to obliterate trenches and boyaux and interior barbed wire entanglements. Trench mortars serve to destroy the elements of the first line and its accessory defenses. =Plan of Artillery Action.= The details for the execution of these different artillery fires are laid down in the plan of action of the artillery of the army corps or of the division. This plan is a part of the plan of battle of the division. These details must be carried out punctually and with precision. The sector commanders are not interested directly in the execution of these fires, but they are in their results. =Duties of the Infantry during the Artillery Preparation.= In connection with the artillery fire, the infantry in the position must observe the results of the bombardment and the leaders report their opinion upon its control.