1. The grenade thrower puts grenades: (1) into bay 1, at _A_; (2) into bay 2, at _D_; (3) into bay 1, at _B_; (4) into the traverse leg at _C_. 2. When the four grenades have exploded the bayonet men rush into bay 1, the leader advancing into the first leg of the traverse trench below _B_, while his mate remains in the bay for a moment. [Illustration: _PLATE 40._] 3. The squad leader rushes around the traverse to _A_, followed by the grenade thrower. 4. When the bay and the next traverse passages are all cleared of the enemy the word “O. K.” is passed back to the squad leader by the bayonet men. The bayonet men get into their proper positions and the remainder of the squad rush into the cleared bay 1 and prepare for the further clearing of succeeding bays in the same manner as described above. Take the diagram on Plate 40. Study it out in connection with the text and you will see how this system works out. The men work in pairs, the two bayonet men together; the two carriers behind the thrower; the two barricaders sufficiently far to the rear to be protected by a corner of solid earth. The squad leader must of necessity go where his presence is necessary. Usually he stays as near the grenade thrower as possible. When the enemy’s grenadier parties are also very active in the sector, the distances between pairs are extended so that no more than two men are exposed in any one bay or traverse leg. The formation of the squad must be preserved as long as possible. You will appreciate that when losses occur the squad leader will have to replace men and the formation will have to be modified to meet the changed conditions. This makes it absolutely necessary that every member of the squad be competent to take over the duties of any other member. When the squad has reached the limit of its advance the barricaders will come forward and construct a barricade in such position that it is well in view from a corner some distance behind. 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. [Illustration: PLATE 41 _Combat in a Communicating Trench_] 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