=Casualties.= Every man must be trained to take up the duties of any other man in his squad. They do not necessarily keep to their own squads; the squads in rear of the attacking squad may be looked on as a reserve squad for the one in front. Thus, Casualty first squad. The thrower No. 3 is reinforced by the first thrower of the second squad, and so on. =Side Trenches.= When a side trench is met with, the leading squad will go up and clear it. The second half will remain at the junction until first returns, then the second squad will continue advance in original direction of the attack. =Blocking and Barricades.= For blocking captured trenches, etc., see Manual of Field Engineering, Wire Entanglements, Hurdles, etc. FOREIGN GRENADES. FRENCH The description of British and German grenades apply also to those grenades used by the French army. They are: 1. Three kinds of petards. 2. Pear-shaped percussion grenade hand. 3. The “Besozzi” grenade. [Illustration: BALL GRENADE.] =1. BALL GRENADE OR FORTRESS GRENADE= =Description= =Igniter.= Friction tube with wire pull let into wooden fuse. =Safety Devices:= 1. The fuse is carried separate. 2. The plug is covered with paper. 3. The wire pull is bent to prevent a direct pull of the fuse. =To Use.= See German spherical Grenade, p. 43. =2. PEAR-SHAPED GRENADE—Percussion= =Description= =Igniter.= A copper tube containing striker, creep spring and detonator. [Illustration: PEAR-SHAPED GRENADE.] =Safety Devices:= 1. The cams lever secures striker while the lever is held in place against body of grenade. 2. The strong loop which holds lever against body of grenade and is fastened by a metal seal. =How to Use;= 1. This grenade is always =“alive.”= 2. Holding grenade in right hand, neck towards the wrist, the lever against the palm of the hand. 3. Pull off the metal seal with left hand. 4. Throw the grenade. NOTE. This grenade must be carefully handled; it is carried and packed “alive.” [Illustration: BESOZZI GRENADE.] 3. BESOZZI GRENADE Description =Igniter=: 1. Time fuse which projects from the grenade. 2. Red phosphorus tipping to fuse. 3. Detonator. =Safety Devices=: 1. The grenades are packed in waterproof paper. =To Use:= 1. Holding grenade in the right hand, fuse upwards. 2. Strike the phosphorus tip with a downwards motion of the left hand, with the striking box. 3. Throw the grenade at once. NOTES. 1. Fuse burns 5 seconds. 2. These grenades are always carried alive. 3. A special ring or striking box is provided to light the fuse. =Foreign Hair Brush Grenades.= They are similar to the British No. 12 Hand Grenades. GERMAN GRENADES There are two types: No. 1. Service grenades. No. 2. Improvised or home-made grenades. These are again divided into two classes: