For this reason machine guns should open fire on any body of the enemy presenting a good target, even at long range, if they are moving to attack the convoy. The presence of machine guns with a convoy will free the infantry to move out wide on the flanks in open country, and to push ahead to piquet hills, clear bush, and occupy heights on the line of march, without exposing the convoy to danger during their absence. BLOCKHOUSES Blockhouses have been much used in warfare in uncivilised countries ever since the introduction of firearms, to enable small detachments on a frontier or on the lines of communication to maintain themselves in the midst of the enemy when unsupported by other troops, and also to form a chain of posts across an enemy’s country for the capture or suppression of guerilla bands. Looking back to the South African War, it appears inexplicable that little or no use was made of machine guns to hold the long blockhouse lines which stretched for so many hundreds of miles in every direction during the latter stages of the war. Time after time the Boers succeeded in breaking through this line, even in places where the blockhouses were within effective range of each other and the intervening space guarded by elaborate barbed-wire entanglements. The reason for this is not difficult to discover. Screened by the darkness, the fire of the small garrisons of these blockhouses was neither sufficiently powerful nor accurate to stop the majority of the enemy from breaking through, even though stopped by the entanglements and compelled to use a single gap. The annihilating and concentrated fire of machine guns which had been laid by day to sweep the entanglements should render the forcing of a similar blockhouse line impossible in the future. Machine guns in detached blockhouses should be sited as low as is compatible with a good field of fire, and should have long narrow loopholes prepared for them for at least two positions on every face. Constant change of position within the blockhouse after firing will prevent the enemy from being able to “snipe” the gunners through the loopholes. The great variety of conditions and circumstances under which minor operations take place renders it impossible to do more than show how they may be used in certain selected instances. The machine gunner must be prepared to modify and adapt his tactics to suit the special circumstances of the expedition with which he is employed, and he cannot do better than study Callwell’s _Small Wars, their Principles and Practice_, which has been so freely quoted in this chapter. ENCLOSED COUNTRY