In order that “fire” may be “effective,” it is necessary to bring the enemy within the zone beaten by 75 per cent. of shots, and it has been found by experiment that 25 per cent. of shots fall immediately in front and behind the target, then 12½ per cent., 7½ per cent., and, finally, 5 per cent. scattered far in front and behind. [Illustration: DIAGRAM II TO SHOW THE DISPERSION OF BULLETS] Infantry usually fire at the rate of three rounds a minute “slow,” and fifteen rounds a minute “rapid”; “slow” fire is the ordinary rate, and “rapid” fire can only be effectually maintained for about four minutes; but this is when the firer is fresh, and has not been subjected to several hours’ marching and fighting as would be the case in battle, and it is doubtful if “rapid” fire can be kept up on service for more than one-and-a-half to two minutes without becoming wild and consequently ineffective. On the other hand, “rapid” fire is less tiring to the machine gunner than “deliberate” fire; the gun is held for him by the mounting, it loads and fires itself, while elevation and direction are maintained without the least exertion on his part by the elevating and traversing gears. In comparing the volume of fire of the machine gun with that of a body of infantry, it is obvious that “rapid” cannot be taken as the normal rate of infantry fire, as it can only be used for the shortest periods, and even then it reduces the users to a state of inefficiency as regards accuracy in two or three minutes. On the other hand, “rapid” fire can only be used by the machine gunner on special occasions, for tactical reasons which will be explained later, so that it will be necessary to compare “slow” infantry fire with “deliberate” fire from the machine gun, in order to arrive at the mean fire volume of each. Seventy shots a minute can easily be fired “deliberately” from a machine gun, and this could be increased to 120 by highly trained gunners, but, taking the lower figure, deliberate fire equals in volume the fire of twenty-four men using rifles. But it must be always remembered that the object of the fire fight is to bring a concentrated and overwhelming fire to bear _at the right moment_ on certain positions of the enemy, and when the moment arrives machine guns can and will use the most rapid rate of fire possible, which will be from 250 to 300 rounds a minute or equal to that of 50 or 100 riflemen. Mere volume of fire, however, is useless without control, accuracy, and concentration, and it is here that the machine gun is so vastly superior to the rifle; for amongst 50 men using their rifles there can only be a small percentage of good shots, while even among the good shots unforeseen factors, such as fatigue, bad fire positions, excitement, wrong sighting, failure to see the target, etc., cause a large percentage of the shots to go astray, and make it very difficult to concentrate the fire on any particular position of the enemy.