No passing of bombs forward from man to man is permitted. When the first carrier's supply is exhausted he returns to the rear to secure a fresh supply from the reserve grenade carriers who are following the grenade squad, and who have by now advanced to a point where their supply is available. As soon as his supply is replenished he returns to his proper position in the formation. Should the second carrier run out of grenades the squad leader may cause one of the barricaders to take all the grenades in the possession of the two and replace him while he goes to the rear to secure a fresh supply. In the meantime other grenadier squads are clearing out the communication and supervision trenches, blocking up the exits to dugouts and destroying machine-gun detachments that have thus far escaped. The assaulting troops have passed on towards the second line, covered by the curtain of fire of the artillery. CLEARING COMMUNICATION TRENCHES The clearing of communication trenches is effected much in the same manner as explained for the fire trench. The grenadier squad is organized and formed in the same manner. The squad works its way into the communication trench by bombing each leg until they arrive at a point where the formation, as illustrated in Plate 41, can be assumed. The grenade thrower throws grenades into the trench at _B_ and then at _C_. As soon as these have exploded the bayonet men take advantage of the confusion to advance into the leg _A-B_ under cover of the shoulder _b_, the squad leader and thrower advance to _A_, the carriers to the point formerly occupied by the squad leader, and the barricaders to the point formerly occupied by the carriers. The thrower then puts grenades into the trench at C and then at D, after which the whole squad advances another notch as formerly explained. Where island traverses are encountered the thrower puts a grenade on each side of the traverse and one in the rear of it. The bayonet men, one on a side, assault around the traverse and meet on the far side, and the operation proceeds as heretofore explained. NIGHT OPERATIONS The grenadier squads may be called upon at night, to perform any of the services that are theirs by day, and in addition may be called upon to make night reconnaissances. For this work the men must be able to organize and reorganize the squad quickly and noiselessly. The throwers must be particularly efficient. There must be the highest order of team work. GRENADIER PATROLS Grenadier patrols are sent out at night to make reconnaissances of the enemy's lines with a view to getting information which may include: 1. Location and organization of line. 2. The length of line occupied. 3. Numbers and disposition of occupying troops. 4. To get an accurate description of the ground. 5. To locate observation and listening posts or any other advanced positions. 6. To locate machine guns.