Used with the rifle, this grenade has a maximum range of 400 meters. At the extremity opposite the grenade, the copper rod ends in a copper stem about 3 centimeters in length, movable about the axis of the rod. This stem is covered with a copper sleeve of slight thickness, which is attached to it only at the extremity fastened to the rod. The diameter of the exterior of the sleeve must be such that it can be pushed into the gun barrel without pressure. To fire the grenade, a blank cartridge is placed in the chamber of the rifle; the quantity of powder left in the cartridge is regulated according to the distance at which the missile is to be thrown. At the moment of firing, the explosive gases penetrate between the sleeve and the stem and jam the sleeve against the grooves of the barrel. The sleeve and the stem, which is attached to it, take a movement of rotation in the grooves of the barrel, which insures the direction of the missile and the maximum efficiency of the explosive gases of the cartridge. [Illustration: Plate 41c.--The latest type British hand grenade.] The bracelet grenade and the German grenade just described have to be made in a factory. Attempts have been made to construct similar missiles with the explosives which are at hand at the front, cheddite and melinite. Several kinds have been made: a primed cartridge and a primed hand petard, fitted on a wooden paddle, a preserved meat tin can filled with explosive, etc. The Germans have hand petards similar to those of the Allies but with different explosives. These missiles are primed by a detonator and a slow match and can be thrown about 30 meters. The discharge takes place either automatically or by tinder. They are made on the spot and very rapidly. The assaulting troops carry them in baskets or strung on a circle of wire carried on the shoulder. [Illustration: Plate 41d.--Throwing hand grenades.] Grenades and petards constitute a terrible weapon. The projectiles exert considerable moral effect owing to the violence of their explosion and the awful wounds they occasion, and they make it possible to reach the enemy at points where it is impossible to use the rifle and bayonet. CHAPTER IX GAS WARFARE Germany first made use of poisonous and asphyxiating gases on the field of battle. It has become an accepted element in the present war. Every soldier should, therefore, have a knowledge of the various ways in which gas is employed in the attack, as well as the measures to be taken to counteract its effect in the defense. The two methods of disseminating the gas over the battlefield are by emanation and grenades charged with it. EMANATION