When it is remembered that this mitrailleuse was not automatic, but had to be operated by hand, that it had 25 barrels and a maximum effective range of only 500 yards, and that it cheerfully engaged in the artillery duel at ranges between 2,000 and 4,000 yards, the only wonder is that, having accomplished so much, the reasons for its failure were not immediately apparent, and that it has taken nearly forty years to convince the world that tactics are as necessary for the effective employment of machine guns as for infantry. The general principles for their tactical employment have already been dealt with in Chapter II., but they are so excellently condensed in Sect. 187 of the German Regulations, that at the risk of repetition they may be quoted here. “Machine guns enable commanders to develop at fixed points the maximum volume of infantry fire on the smallest possible front. Machine guns can be employed over any country that is practical for infantry, and when they are unlimbered they must be able to surmount considerable obstacles. In action they offer no greater target than riflemen fighting under like conditions, and they can, in proportion to their fire value, support far greater losses than infantry. They can utilise all cover that infantry are able to use. Cover which is barely sufficient for a section of infantry (60 men) can protect an entire machine-gun detachment (six guns).” In order to see in more detail how machine guns should be employed with infantry and the limitations of their tactics, it will be necessary to follow the sequence of the infantry combat in attack and defence, and to assume such situations as seem likely to arise. ADVANCED GUARDS The action of the infantry of an advanced guard will follow the same lines whatever the dimensions of the force, and the battalion is a convenient unit with which to deal. There are four battalions in a brigade, and three brigades in a Division; consequently the Divisional General will have six batteries of four guns each, or 24 machine guns, under his command. We will assume that the battalion we are dealing with forms the advanced guard of its brigade, and that the Brigadier has given it a battery of four machine guns, two of which will probably belong to the battalion. _Field Service Regulations_, 1909, page 79, says: “An advanced guard is divided into a vanguard and a main guard.... The special duty of the vanguard is reconnaissance. It will therefore generally be composed of the advanced guard mounted troops, with or without a body of infantry as a support. By day, when the country is open and the advanced guard is strong in mounted troops, infantry will not as a rule form part of the vanguard.... The main guard comprises the troops of the advanced guard not allotted to the vanguard.”