The types of hand grenades (b), (c) and (d) differ fundamentally in the means by which ignition is effected; (b) explodes instantaneously on impact (by percussion), while (c) and (d) are fired by time fuse, which is lit in (c) by spring action releasing a trigger at the moment the grenade leaves the thrower’s hand, and in (d) by an independent action on the part of the thrower before throwing the grenade. In the case of (b) it is necessary that the grenade fall head first. This is done by the backward pull in the air of the streamers attached to the handle. In using this grenade it is, therefore, necessary to see that the streamers are opened out and free--before throwing, and to throw the grenade well upwards. In the case of (d) the total time of delay is slightly over 5 seconds, so that from 1-1/2 to 2 seconds should be used in throwing. If thrown hastily it may arrive at the mark 3 seconds before exploding and allow it to be returned by the enemy. When handling detonators for grenades, it should be remembered that the detonator by itself is capable of blowing the hand off, so it must be carefully handled, and if an igniter is accidentally fired it should be thrown a few yards clear of any one in the neighborhood. When the igniters and detonators are in the grenades reasonable care should be taken to avoid rough usage as violent treatment might fire the grenades, even in the safe position. =Grenade .303-inch, Short Rifle, No. 3, Mark 1 (J. pattern). Description=: The grenade consists of a steel body filled with explosive. Down the centre of the explosive is a brass tube into the forward end of which the detonator is inserted. The rearward end of the body is closed by the base piece which carries the needle pellet, two retaining bolts, wind vane and releasing socket with safety pin. To the base piece is fixed a base plug carrying the spring clip and a 10-inch steel rod. The action of the grenade is that, the safety pin having been removed, on firing the releasing socket sets back from under the wind vane, which is then revolved by the wind pressure as the grenade travels through the air. After a few turns of the vane the retaining bolts are no longer held in position by its inner surface. On impact the needle pellet sets forward against the creep spring, on the detonator cap, firing the grenade. The steel body is serrated so as to furnish numerous missiles. =Package of Grenades=: The wooden box provided carries 20 grenades in protecting tins with screw-off lids, 20 detonators, rifle grenades in four tin boxes with lever lids, and 22 special blank cartridges in a tin box. =Preparation for Firing=: The grenade is removed from its tin and the ebonite plug in its head is unscrewed by hand. The grenade is held nose down to make sure that the needle pellet is held by the retaining bolts. If correct, the detonator is inserted and screwed home.