4. This lack of co-operation is seen both in the open and in trench work. All this points to the fact that co-operation between the whole of the machine guns taking part in any action is not sufficiently studied. GUNS BRIGADED IN ACTION. On many of the occasions brought to notice in which machine guns have been brigaded they have achieved marked success, but on the whole not sufficient use has been made of this method of obtaining the combined action of a number of guns. “Brigading” guns does not mean “massing” them. It means the “brigaded” guns are employed with some definite plan under the direction of one Officer. In all cases where the action of brigade guns has been successful there has been:— 1. A thorough understanding of the plans of the Brigadier by the B.M.G.O. 2. Conference between the B.M.G.O. and the Section Officers at which the arrangements for the employment of the machine guns were fully discussed. 3. Definite orders to the Section Officers. 4. A proportion of the guns held in reserve under the B.M.G.O. But when the sections have been hastily collected together and placed under the B.M.G.O., without time for making the above arrangements, the result has usually been that sections have been dispersed without definite orders or a complete understanding of the situation, and effect has been lost. In trench warfare the successful co-operation of the machine guns assisting in the defence of any particular section of the entrenched line has been obtained by:— 1. A previous reconnaissance of the whole line by the B.M.G.O. 2. Diagrams made of own and enemy’s trenches. 3. The number of emplacements. This has enabled rapid concentration of the requisite number of guns only on any one portion of the enemy’s line, and has prevented unnecessary opening of fire and the consequent waste of ammunition. In many cases, however, Officers in command of troops in sections of trench line have considered they are also in command of the machine guns placed in that portion of the trench occupied by their troops. This has led to:— 1. The disadvantage of dual control. 2. The guns being placed in the same emplacement day after day. 3. The arrangements of Machine Gun Officer being interfered with. 4. The guns being located by the enemy through an unnecessary opening of fire ordered by an Officer who is not an expert in machine gun tactics. FIRE ORDERS. The system of fire orders as taught at Hythe previous to the war has been most successful. Machine Gun Officers are also of opinion that, though it has often been impossible to give orders by word of mouth, the systematic training of all ranks in this system tends to ease of control under difficult circumstances, and when a number of guns are being employed for combined action.