In modern warfare large guns are used either to rain a storm of death upon infantry or to destroy their defensive works. In earlier days the effectiveness of gunfire against a charging enemy was increased by the use of grapeshot. A cannon was thus converted into a gigantic shotgun. But although a wide dispersion of projectiles was obtained the range was very limited. This handicap was then overcome by having the gun fire another gun which would discharge when it had reached the enemy’s lines. In other words, the grapeshot or leaden balls were packed into a shell which was fired like a solid projectile, and this exploded when it struck the target, scattering death broadcast. An improvement on this was the timed shell, which would explode while still in the air and scatter its rain of lead over a wide area. The time fuse of a shrapnel shell must be very delicately adjusted to explode at the desired instant. A train of powder is used which may be short-circuited to give the exact length required for any given distance. The powder is ignited by a cap which is exploded by concussion when the gun is fired. The fuse then burns until it reaches the main charge of the shell. This explodes, bursting the shell open and scattering shell fragments as well as the scores of lead balls with which the shell is packed. Should the fuse fail, a detonating pin is provided which will explode the shell when it reaches the ground. Where the object is to destroy defensive works the shell is charged with a high explosive which is detonated not by a time fuse, but by concussion when the shell strikes its target. The war brought forth many new types of projectiles: shells loaded with lethal gases; shells which left a trail of smoke whereby their course could be followed when fired at aircraft; shells that illuminated the battlefield at night, etc. The searchlight shells carried a number of “candles,” each furnished with a little parachute so that when the shell exploded the burning candles would settle slowly to the ground, all the while casting a brilliant light on operations below. AERIAL BOMBS Obviously, hurling projectiles from the air is a much simpler matter than projecting them from the ground. No propellant is required to carry them to the target and no rifling is necessary to keep them head-on in the direction of flight. They are pulled instead of being pushed and can easily be kept in their course by means of rudder planes. But hitting a target from an aeroplane is like hitting a swiftly moving object from the ground. The target is seemingly flying past the aeroplane and in calculating where the aerial bomb will strike the speed of the plane through the air and its height above the ground must all be taken into consideration.