=Method of Advance.= It is usually the endeavor to bomb and clear three bays at a time in advance of the bayonet men. The N.C.O. reports the throwing by the word “Mark,” to indicate a burst in the required bay. On the third mark having been registered, the N.C.O. gives the order, “Bayonet men report.” They immediately advance up the trench to the last bay cleared and report back after examination either “All clear” or “Enemy holding,” whereupon the N.C.O. gives the order “Advance,” or directs the thrower to bomb the last bay again. This means of advance is continued until the objective is gained. =Island Traverse.= The two methods of attack are employed as shown on the chart. It is imperative that the attack must not be allowed to be held up, and should it be found impossible to advance down the trench itself, owing to enfilade fire, the attack must be immediately launched outside the trench, so as to attack the traverse from the rear, in the case of a daylight attack. =Precautions.= Care must be taken, especially by the bayonet men in their advance through the trench, that enemy concealed trenches, dug-outs, etc., are not left undiscovered. The sides of trenches and the walls and floors of dug-outs should be carefully examined for concealed entrances or exits. FRONTAL ATTACK IN CONJUNCTION WITH INFANTRY =The Preparation Before an Attack.= The following details must be carefully considered: (_a_) The study of operation orders. (_b_) The linking up of observations gained from the 1. Study of existing trenches and aeroplane maps of enemy positions. 2. The personal reconnaissance of the topographical features of the ground to be covered in the advance. (_c_) The detailing of squads to their special objectives and the arranging for work, carrying wire and demolishing parties for permanent blocks at the final objectives. [Illustration: FRONTAL ATTACK.] (_d_) The kind of grenades to be used with a view to facilitating the carrying of same. (_e_) Carrying parties must be told off to insure supplies of grenades reaching the throwers. (_f_) Grenade depots must be built, sign boards arranged for, and clearly marked “Grenade Depot” not only in our own system of trenches, but also the positions told off beforehand where they are to be established in the enemy trenches, or in =No Man’s Land= immediately previous to the attack. (_g_) Responsible officers and N.C.O.’s should be told off to look after the grenade depots and supply of grenades. (_h_) The position for infantry grenade dumps must be selected and clearly explained to all units taking part in the attack, and special parties told off to collect at these points and carry grenades to nearest depots. (_i_) A traffic system should be arranged and all men must be acquainted with it, and the trenches or lines of travel clearly marked “up traffic,” etc. =The Advance.= =1. In line with infantry.= =2. In advance of infantry.=