All the suggested methods have been used, and in some cases compasses and maps as well. Effect has been obtained in the open and on enemy’s concentrations at long ranges, and in trench warfare on working parties, ration parties, communications, etc., behind the enemy’s lines. A great deal more could be done in this way if all guns were not almost invariably placed in trenches, instead of a proportion being placed in suitable positions in rear, and long-range fire employed. All this points to the fact that a Machine Gun Officer should be acquainted with all methods of employing indirect fire, in order that he may be in a position to make the best of any opportunities that may occur. CLOSE CO-OPERATION BY MACHINE GUNS WITH THE FRONT LINES OF ATTACKING INFANTRY. Very little information has been given on this subject, but co-operation seems to have been very poor; but this co-operation is made very difficult in many cases by:— 1. Inability of the M.G. sections to keep pace with the attacking infantry. 2. The visibility of the methods employed of carrying the gun. This leads to many casualties. 3. Lack of tactical knowledge on the part of many of the more junior M.G.Os. 4. Lack of definite plans as to the role of the M.Gs. before the action commences. The two following examples serve to illustrate some of the above:— 1. In a recent attack, owing to lack of any previous understanding between M.G.Os., eight M.Gs. converged into one small section of a captured trench. Owing to lack of space only two of these guns were able to come into action. 2. In another instance during an attack, six guns converged into one small house. Owing to lack of space, etc., only two of these guns were able to come into action. Before an attack a certain M.G. Officer was told to await orders from his Commanding Officer. He was forgotten and left behind. In this case, as soon as the Officer realized that he had been forgotten, he should have used his own initiative. All these point to the fact that some arrangements for concerted action should be made. N. B.—See “Guns Brigaded in Action.” OBTAINING AMMUNITION FROM LIMBER FOR GUNS WHEN ATTACKING. 1. The usual system of using Nos. 3 and 4 as carriers is generally adopted. Often these numbers are not sufficient for the work. It is then necessary to borrow men from neighbouring squadrons or companies. 2. The bringing up of ammunition is dangerous work; therefore it is obviously best to avoid employing trained gunners if unskilled men are available. 3. In this manner you conserve your trained gunners for replacing casualties. 4. Pack animals can sometimes be brought close to the firing-line when the ground is favourable, thus saving manual labour. 5. Several instances are given of confusion occurring during an attack, owing to the limber moving without orders. This should be guarded against. CHIEF MECHANICAL TROUBLES.