sufficient accuracy to ensure bringing the "effective zone" on the target.
For ranges over 500 yards it is absolutely necessary to know the range accurately or to find some other method of bringing the "effective zone" on to the target.
The machine gunner may be likened to the fireman with his hose-pipe, whose object is to bring the base of his jet of water to play on a certain spot some distance away from the nozzle of his pipe. He does not trouble about the distance, he does not require to know the range; but pointing the nozzle in the direction of the spot he desires to strike, he elevates or depresses it until he observes the base of the cone of water falling on the right spot, and then he holds his pipe so that it continues to fall where he desires; he does not trouble about the smaller streams and drops of water that fall short or go beyond, but devotes his whole attention to keeping the nucleus of the stream—the 75 per cent. or 50 per cent. zone—falling on his "target." In precisely the same way the machine gunner must look upon his stream of bullets as a stream of water from a hose-pipe, and his object must be to cause the centre of that stream to play on the target, or, in other words, to bring the effective cone of fire on the target so that it is the centre of the beaten zone. This can be done by "observing" the strike of the nucleus of the shots and altering the elevation accordingly. On favourable ground fire can be observed by
