the development of machine-gun tactics was made, for which the Canadian Corps must be given full credit. The Canadians had devoted much thought and care to their machine-gun organiza- tion and. had determined to organize and employ their machine- guns on a divisional basis. They also determined to make full use of the offensive power available in machine-gun fire, for which purpose their machine-gunners had perfected them- selves in the use of overhead and indirect fire, and had ob- tained the equipment necessary for carrying out the latter. The highly successful machine-gun barrage arranged by the Canadian Corps for the support of their infantry in the attack on Vimy Ridge was the first example of the coordinate action of a large number of machine-guns in the British attack. The machine-gun arrangements made by the Canadian Corps were enlarged on in the battle of Messines in June 1917, with highly successful results. Subsequently machine-gun barrage fire, coordinated with the artillery barrage, became a regular feature in all the operations of the British army, whether offensive or defensive, as long as the period of trench warfare continued.
The use of barrage fire led to considerable strides in the development of machine-gun tactics. It proved beyond doubt that the Vickers gun was fully capable of accurate long-range fire and of carrying out overhead and indirect fire with safety, with the result that most of the British infantry units would by this time advance under the fire of their machine-guns with complete confidence. The use of barrage fire also necessitated coordinated action between machine-gun companies, and thus pointed the way to the higher organization of the Machine-Gun Corps. By this time it was realized that the value of the disposition of machine-guns in depth, not only in defence but also in attack, was enhanced by a combination of direct and indirect fire. Consequently machine-guns were now divided into two main categories forward guns and rear guns. In the attack the forward guns were allotted the role of affording immediate support to the leading troops and of assisting in the consolidation of the final objective.
The rear guns supplied long-range covering fire, generally organized in the form of barrage fire, from positions in rear. It must be remembered that at this time the operations still consisted entirely of trench-to-trench attacks with limited objectives, and it was generally possible to site the rear guns so that they could cover the advance of the infantry up to the final objective without moving from their original gun positions.
In any case it was unusual for the rear guns to be obliged to make more than one forward move during the operation.
In the defence the forward guns were allotted for the defence of the outpost line of resistance, whilst the rear guns were disposed in depth for the defence of the battle position. The primary task of the rear guns was the defence of specific areas by means of direct fire; but as a secondary task, subject to limitations as to expenditure of available ammunition, as many of these guns as possible were utilized to afford long-range fire (either direct or indirect) for the assistance of the troops in the more forward areas. No hard-and-fast rules were laid down as to the proportion of forward guns to rear guns, but it was realized that the number of the former must be kept to the lowest possible minimum in ordar that there might be sufficient depth in the machine-gun dispositions.
By the end of 1917 the following conclusions were also drawn by those who had made a continuous study of machine- gun tactics, (i.) That machine-guns are as valuable in offensive as in defensive operations, (ii.) That, except at close ranges, the fire of one machine-gun is of little tactical value. That the section of four guns is the tactical unit for all purposes of fire direction and control, (iii.) That the machine-gun is a dis- tinctive weapon with tactics of its own, which are neither those of the infantry nor of the artillery, but intermediate between the two. (iv.) That adequate depth in machine-gun dispositions can only be attained and maintained by means of a suitable organization, enabling machine-gun resources to be disposed according to tactical necessity.
Before the end of 1917 it had become apparent that the
British machine-gun organization was not suitable for puttirj into practice the tactical principles enunciated above. Th system of having a machine-gun company definitely and per- manently attached to each infantry brigade had proved to very wasteful. Eventually approval was given in Jan. 1918 to the formation of divisional machine-gun battalions. From ; tactical point of view the following important results followed :- (a) The principle that machine-guns should be allotted and fought on a divisional basis was conceded, and (6) the divisional machine-gun officer, who was merely an adviser, was replaced by a commander who was also an adviser. At the same time it was agreed that the Machine-Gun Corps should be granted higher representation to the extent of the appointment of inspector of machine-gun units (brigadier-general) at G.H.Q. and of a deputy inspector (colonel) at each army headquarters.
The following brief statement of tactical principles, which were put into practice during the closing stages of the 1918 campaign, indicates the final stage in the evolution of machine- gun tactics during the World War. The section of four guns is the tactical unit of machine-guns and should be kept intact The maximum fire effect is obtained by the employment collective fire from a number of guns operating under one control. The use of individual machine-guns, operating alone, results in loss of control, difficulty of supply and dissipation of fire-power. Unity of control is essential if full use is to be made of available resources; within reasonable limits, the larger the number of machine-guns which can be placed under one directing authority the less will be the overlapping of functions and consequent waste of fire-power. Disposition in depth is essential and must be a guiding principle in machine-gun tactics. It enables flexibility of control to be maintained and automatically affords protection to flanks. Unless there is a general pre- arranged and comprehensive plan for the action of machine-guns, machine-gun units will not be able to render that continuous support during the attack which is necessary if fire superiority is to be gained and if the demoralization of the enemy is to be effected at each successive stage of the advance.
Cooperation is the foundation upon which successful machine- gun tactics rest. To ensure it, the closest possible liaison must be maintained between machine-gun units themselves, and between machine-gun units and other arms. Sustained fire and surprise effect are both dependent upon the skilful use of ground and cover while the gun is being brought up to its position and when it is in action. At close and medium ranges, enfilade fire gives the best results with the minimum expenditure of ammuni- tion. Normally, frontal fire at these ranges should not be used unless an exceptional target presents itself, such as troops in mass. In an offensive operation the fullest advantage must be taken of the mobility conferred on machine-gun units by the use of limbered wagons and pack transport. Resort must only be made to man-handling when all other means of transport have been found impossible. In the attack the first duty of machine-gun units is to assist the advance of the infantry. They must carry out this task by providing covering fire, both direct and indirect; by dealing rapidly with serious hostile opposition, and by producing the greatest fire effect at points where the progress of the infantry is checked. Their other duties are to protect the flanks of the infantry against counter-attacks during the advance; to form pivots upon which the infantry can rally if driven back; and to act as a reserve of fire-power in the hands of commanders for offensive or defensive purposes as the situa- tion may demand. It follows from the above that the disposition of guns in depth must be maintained throughout. In the defence the r61e of machine-guns is to assist the infantry in maintaining their positions. For this purpose machine-guns must be. em- ployed (i.) To assist the infantry in the outpost zone to check and disorganize a hostile attack, (ii.) To assist in the defence of the battle position, should the enemy succeed in crossing the outpost zone, (iii.) To support the infantry and tanks in the execution of counter-attacks.
The bulk of the machine-guns available with divisions in front line must be disposed for the defence of the battle position,
