In order thoroughly to understand the methods that should govern the tactical employment of machine guns, and their place in the battlefield, it is first necessary clearly to realise their nature and potentialities, and for this purpose we will examine their principal characteristics. Guns of this class are capable of firing service small-arm ammunition at the rate of 800 shots in one minute, but this very high rate of fire is obviously undesirable for several reasons--the principal, from a military point of view, being that, however skilfully the gun is handled, a great waste of ammunition must ensue, and hundreds of shots be wasted in space, however accurate the fire. These guns are, therefore, regulated to fire at a maximum rate of from 400 to 500 rounds a minute, or seven to eight shots a second, but even this is greater than is necessary to obtain the maximum fire effect; at ordinary targets 100 to 250 rounds a minute, according to the nature of the target, has been found to give the best results in practice. The “rate of fire” of a gun must not be confused with the number of rounds that can be fired from it effectively in one minute; the necessity for frequent pauses to observe the effect, to correct the elevation and direction of the fire, prevent a greater number than from 150 to 250 shots being fired effectively in one minute from a gun whose rate of fire is 450 shots a minute. Colonel Mayne, in his book _The Infantry Weapon and its Use in War_, says: “The machine gun now in use can fire about 600 rounds a minute, or ten a second. This is a far greater rapidity of fire than is really necessary, for it means that a man or horse is struck several times before falling. It is a good thing to be able to fire 600 rounds a minute on occasions (such as for range finding), but a far slower rate of fire (say 100 rounds or even less a minute) is ample for all ordinary tactical purposes against living beings and animals, whilst causing an enormous saving of ammunition.” The extreme range of this type of gun is for all practical purposes the same as the infantry rifle--about 3,500 yards--though it is more effective at the longer ranges than an equal volume of rifle fire, owing to the ease with which the firer can elevate and aim the gun on its mountings and the stability of this mounting, which causes it to have a beaten zone of only half the depth and nearly half the width of that of infantry firing the same number of rounds. This has been proved again by actual experiment at the schools of musketry in England, India, and South Africa, while very elaborate experiments and trials carried out in Germany with the Maxim gun on the carriage adopted for that service proved that the beaten zone was only one-sixth of that obtained by infantry, probably because of the greater stability of their mounting. [Illustration: DIAGRAM I TO SHOW THE ZONE BEATEN BY 50 PER CENT. OF BULLETS]