D.—=Some in Reserve under the Brigade Commander.= These should be retained as a real reserve and not pushed too early into the fight. If the attack is to consist of more than one phase, that is to say, of two or more distinct advances, separate plans must be made for each. Arrangements for the supply of ammunition, belt fittings, ammunition depôts, etc., must be made before the action commences. One Officer should be placed in charge of these arrangements. The B.M.G.O. should remain with the Brigadier. He should provide himself with a suitable number of orderlies. CO-OPERATION. The necessity for co-operation between the machine guns taking part in any particular action cannot be overestimated. Not only should the individual guns of a particular unit work upon some definite plan for mutual support, but the sections of all units that are operating together should co-operate with a view to obtaining the best results from their combined actions. This cannot be done in action unless previously practised. Therefore attention should be paid to training numbers of guns to operate together for some specific purpose. RANGES. The ranges fired at have varied from 15 yards (at which, in one instance, a German rush was stopped), to 2,800 yds., at which range a battery of the enemy’s field artillery was silenced. This brings out the importance of:— 1. The allowance for wind at long ranges. 2. The importance of range-taking, range cards, judging distance, visual training, reference points, etc. 3. Practice of the “Swinging Traverse” for stopping rushes and dealing with dense targets at very close range. 4. Practice of traversing by means of the “Automatic Tap” for medium and long ranges. NATURE OF TARGETS FIRED AT. Targets have been of all kinds, such as:— 1. Dense masses at all ranges. 2. Extended lines at all ranges. 3. Artillery on the move and in action. 4. Edges of woods, hedges, ditches, etc., where enemy’s firing-line was known to be, but in many cases could not be seen. 5. Enemy machine guns in all manner of positions, usually invisible to the eye or even with glasses. 6. Hollows, wood, and other cover under which the enemy was known to be concentrating. 7. Searching fire to try and locate and beat down hostile fire that was being delivered from concealed positions. The varied nature of the targets that the machine gunner may have to engage brings out the fact that the machine gunner must be very thoroughly trained, and emphasizes the points brought out under “Ranges, Fire Orders, Indication and Recognition.” FIRE ORDERS. While in a large number of instances it has been possible to give fire orders by word of mouth, this will, as a rule, be only possible under exceptionally favourable circumstances.