CHARACTERISTICS OF THE VARIOUS ARMS

"The full power of an army can be exerted only when all its parts act in close combination, and this is not possible unless the members of each arm understand the characteristics of the other arms. Each has its special characteristics and functions, and is dependent on the co-operation of the others" ("Field Service Regulations," vol. ii.

(1921)).

"An intelligent understanding of 'the other man's job' is the first essential of successful co-operation."--MARSHAL HAIG.

INFANTRY

"Infantry is the arm which in the end wins battles" ("Field Service Regulations," vol. ii. (1921)). The speed with which infantry can advance, and the distance which can be covered in one day, are the only limits to the striking power of well-trained infantry. In the Great War these limits were largely removed by the use of Mechanical Transport, and this means of transportation will be used increasingly in Modern Warfare, in order to bring fresh troops into or near the scene of action, or to expedite the removal of exhausted troops from the battlefield. Against these natural limits to mobility are the compensating advantages of the power of infantry to move into and over almost any ground by day or by night, and the rapidity with which trained infantrymen can find or improvise cover.

The main object of battle is to close with the enemy and to destroy him by killing or capture, and it is this power to close with the enemy which makes infantry the decisive arm in battle.

THE RIFLE AND BAYONET.--The rifle is the princ.i.p.al infantry weapon, and the British "Short-magazine {165} Lee-Enfield" rifle is the best rifle in action. A trained rifleman can fire 15 aimed shots in a minute, reloading with the b.u.t.t in the shoulder and eyes on the mark. With the bayonet affixed the rifle is the princ.i.p.al weapon of close combat for delivering or repelling an a.s.sault, and in Night a.s.saults infantry depend entirely upon the bayonet.

THE ENTRENCHING TOOL, carried by all other ranks, is an invaluable adjunct to the rifle bullet and to the bayonet. In a War of Manoeuvre, when infantry are frequently compelled to improvise defences on the field of battle, by night as well as by day, the value of the Entrenching Tool can scarcely be exaggerated. In Position Warfare, and in the organisation of an area for prolonged defence in a War of Manoeuvre, heavier tools and materials of all kinds are available for the consolidation of the defences, but for the rapid construction of temporary defences by day or by night the Entrenching Tool alone has been proved to be highly effective. When troops are "digging themselves in" at night with this weapon care must be taken that some system is adopted to obtain a more or less regular line facing in the right direction. By the extension of the men of an infantry section at arm's length facing the enemy, and by moving the two men on each flank two paces outwards, and the two centre men two paces backwards, and then causing the section to dig "on the line of their toes," there will result (even on the darkest night) a short fire trench with a central traverse. This sectional trench can be connected at the first opportunity with trenches dug by other sections similarly extended.

During the _Retreat from Mons_ (August-September, 1914) the "Contemptible Little Army," under Marshal French, frequently obtained, by means of the Entrenching Tool alone, shelter from bullets, and a system of fire trenches which cost the pursuing Germans hundreds of lives and materially delayed their movements.

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THE LEWIS GUN.--The Lewis gun is an automatic rifle, firing the same ammunition as the S.-M.-L.-E. rifle, and two Lewis-gun sections are included in each infantry platoon. The rate of fire is increased by the automatic action of the gun, the maximum rate permitting a drum of 47 rounds to be fired in less than ten seconds, while one or two rounds only may be fired if so required. The mobility of the Lewis-gun sections is the same as that of other sections of the infantry platoon.

RANGES OF RIFLES AND MACHINE GUNS

_Close_ range. Up to 800 yards.

_Effective_ range. Over 800 yards up to 2,000 yards.

_Long_ range. Over 2,000 yards up to 2,900 yards.

GRENADES.--Hand grenades and rifle grenades are adjuncts to the rifle and bayonet and the Lewis gun. Their princ.i.p.al use is in clearing fortified posts, especially in Position Warfare. The _hand grenade_, or bomb thrown by hand, is limited in range by the skill and strength of the thrower, and 30 to 40 yards may be regarded as the maximum distance. The _rifle grenade_ is effective up to about 400 yards, and is generally employed to provide a local barrage or to search cover.

In the latter case, a high angle of descent is used as with mortars or howitzers.

LIGHT MORTARS.--The _Light Mortar Section_ is an integral part of every infantry battalion, and although sometimes brigaded for special purposes the sections normally work with their own battalions. A section of 2 light mortars, firing 11-lb. bombs, consists of 1 officer and 20 other ranks, and requires 2 horses and 1 G.S. limbered wagon.

Owing to the high angle of descent the bombs can be fired behind, and can search, high cover, while the mortars themselves are not very conspicuous objects and can be {167} readily moved for short distances, while they "come into action" in 30 seconds. The comparatively slow flight of the bombs, however, enables the enemy to discover the location of the mortars, and necessitates the use of expedients to avoid counter-artillery fire. A maximum rate of 30 to 40 rounds a minute can be maintained for two or three minutes, if ammunition is available, and at an angle of 45 degrees a range of 700 yards can be obtained.

MACHINE GUNS.--"The princ.i.p.al characteristic of the machine gun is its power of delivering a concentrated volume of fire which can be sustained almost indefinitely, subject to limitations of ammunition supply. The ease with which the gun can be concealed in action and its fire controlled enable advantage to be taken of surprise effect"

("Field Service Regulations," vol. ii. (1921)). The _Machine-gun Platoon_ is an integral part of every infantry battalion, but in Attack machine guns are frequently grouped for the purpose of providing overhead or other covering fire, while in Defence they form, with the artillery, the framework into which the defensive dispositions are fitted, and by reason of their fire-power machine guns enable a commander to economise in the number of infantry allotted to a purely defensive _role_. The ranges are those given above for rifles and Lewis guns, and the rate of fire is about 20 times that of a rifle, while 1,500 to 2,000 rounds may be fired continuously at a moment of need.

MOUNTED TROOPS

CAVALRY.--The princ.i.p.al characteristic of cavalry is its mobility.

This enables it to attack unexpectedly; to defend with determination while retaining the power to break off an action more easily than infantry; to gain information and to afford protection at a considerable distance from the force protected; and to confirm {168} and exploit the success obtained in battle. "Cavalry is capable, if required, of undertaking most operations for which infantry would usually be employed, but the demands made by the care of horses reduce the number of rifles which can actually be placed in action; and it therefore lacks depth in comparison with similar infantry formations"

("Field Service Regulations," vol. ii. (1921)). The cavalry arms are the lance and sword for mounted action; horse artillery usually work with cavalry, and the arms employed by cavalry for dismounted action are the rifle, the machine gun, and the Hotchkiss rifle. Examples of the employment of cavalry in modern warfare are given throughout the "Lectures."

MOUNTED RIFLES.--The characteristics and methods of employment of mounted rifles are similar to those of cavalry, with the exception that they are not equipped for mounted action. Mounted rifles, like cavalry, enable a commander to extend his attack or defence in a manner that is most bewildering to infantry, and attempts by infantry to outflank a defending force of mounted rifles are generally frustrated by the mobility of the defending force, as was exemplified in the South African War of 1899-1902.

CYCLISTS.--Under favourable conditions cyclists possess greater mobility than cavalry, and they can develop greater fire-power, as no horse-holders are required. They are, however, dependent upon roads, they are vulnerable on the move, they cannot fight without dismounting, and they must return to their bicycles after action; whereas cavalry horse-holders can meet dismounted troopers at a prearranged spot.

ARTILLERY

"The _role_ of artillery is to a.s.sist the other arms in breaking down opposition, and to afford all possible {169} support to the infantry, with whom the eventual decision rests" ("Field Service Regulations,"

vol. ii. (1921)).

All cla.s.ses of artillery are included in modern military operations.

Motor traction enables the heaviest guns to be brought to the battlefield and to be removed when a commander decides to withdraw from battle, while the increase in the defensive power of obstacles and small arms fire, combined with the increase in mobility afforded by motor traction, enables all but super-heavy artillery (which require a railway mounting) to be placed close behind the infantry in Attack and Defence. It is, however, obvious that the closest support can be given by the guns that are weakest in sh.e.l.l-power, on account of the superiority in mobility possessed by the lighter guns.

In Modern Warfare a great proportion of the work of artillery is carried out, of necessity, in the hours of darkness, owing to the frequency of movement by night to avoid aerial observation, and to the consequent use of indirect artillery fire to inflict losses during such movements. The artillery personnel therefore requires to be relieved with greater frequency than in the days before the use of aircraft.

The growth of artillery during the war was symbolical of the continual changes in the methods of warfare, its numbers and power increasing out of all proportion to the experience of previous wars. "The 486 pieces of light and medium artillery with which we took the field in August, 1914, were represented at the date of the Armistice by 6,437 guns and howitzers of all natures, including pieces of the heaviest calibre"

(Sir D. Haig's Dispatches). "From the commencement of our offensive in August, 1918, to the conclusion of the Armistice some 700,000 tons of artillery ammunition were expended by the British Armies on the Western Front. For the fortnight from August 21 to September 3, our daily average expenditure exceeded {170} 11,000 tons, while for the three days of the crucial battle on September 27, 28, and 29 (_Second Battle of Cambrai_) nearly 65,000 tons of ammunition were fired by our artillery" (Sir D. Haig's Dispatches).

In the Table of Artillery Ranges on p. 173, the effective ranges of light artillery firing H.E. sh.e.l.l are based on the use of No. 106 fuse.

"The invention of a new fuse known as '106,' which was first used at the _Battle of Arras_ (April 9-June 7, 1917), enabled wire entanglements to be easily and quickly destroyed, and so modified our methods of attacking organised positions. By bursting the sh.e.l.l the instant it touched the ground, and before it had become buried, the destructive effect of the explosion was greatly increased. It became possible to cut wire with a far less expenditure of time and ammunition, and the factor of surprise was given a larger part in operations" (Sir D. Haig's Dispatches).

Artillery is cla.s.sed under the designations Light, Medium, Heavy, and Super-Heavy.

LIGHT GUNS.--_Pack Guns_, with a calibre of 2.75 inches, are weakest in sh.e.l.l-power, but they possess a mobility greater than any other artillery and can be moved in country which would present insuperable obstacles to wheeled traffic. _Pack Howitzers_, with a calibre of 3.7 inches, are particularly valuable in close country, the high angle of descent enabling the attack or defence to search the steepest cover.

_Horse Artillery Guns_, firing a 13-pound sh.e.l.l, are the most mobile of all wheeled artillery and are normally employed with mounted troops.

All ranks of the Royal Horse Artillery are mounted, and its mobility is scarcely less than that of cavalry. _Field Guns_, with a calibre of 3 inches, firing an 18-pound sh.e.l.l, are the princ.i.p.al artillery weapon of a field army. Although inferior in mobility to Pack or Horse Artillery, they have greater sh.e.l.l-power and afford the princ.i.p.al support to infantry in closing with or repelling the enemy. Their power to inflict casualties {171} by enfilade fire with shrapnel makes them specially suitable in the defence, and the accuracy of modern weapons enables them to co-operate in the Attack with covering fire, under the protection of which infantry may advance unimpeded to the a.s.sault. In addition to their normal functions, and to their employment in counter-battery work, they can be employed in the reduction of defences by bombardment with High Explosive sh.e.l.ls, in neutralising an area by the use of gas sh.e.l.ls, or in providing artificial cover by the production of _Smoke_. _Field Howitzers_, with a calibre of 4.5 inches, have increased offensive power and practically the same mobility as field guns.

Light guns are the princ.i.p.al weapons for protection against _Aircraft_ and for defence against _Tanks_. The Tank is powerless against artillery, and its most effective enemy is light artillery. During the _First Battle of the Somme_ a new terror was added to the British attack by the introduction of the Tank, which surmounted inequalities in the ground, crushed the wire defences, and crossed the trenches.

Although accompanied by infantry, it was regarded as an all-conquering and decisive factor. At one period of the battle, however, a number of Tanks were placed out of action by a single field gun, manned and fired with the greatest gallantry by a single German artillery officer, who fired point-blank at each Tank as it surmounted the crest of a rise.

Infantry were in close support, and a single Lewis-gun section could have prevented the use of the field gun.

MEDIUM GUNS.--Medium guns, firing a 60-pound sh.e.l.l, are princ.i.p.ally employed in counter-battery work and in fulfilling the functions of 18-pound field guns at a greater range and with greater force. _Medium Howitzers_ occupy the same relative position, their offensive power being greater than that of the Field Howitzer.

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HEAVY GUNS.--Heavy guns of 6-inch calibre, firing a sh.e.l.l of 100 pounds, are used against targets beyond the range of light and medium guns, and with greater effect. _Heavy Howitzers_, of 8-inch or 9.2-inch calibre, are princ.i.p.ally employed against covered batteries and strong defences, or for destroying wire entanglements with instantaneous fuses.

SUPER-HEAVY GUNS.--Super-heavy guns of a calibre of 9.2 inches and upwards are usually carried on railway mountings, and while they possess a high muzzle velocity, considerable sh.e.l.l-power, and a high degree of mobility (which enables them to come into action in any part of the battlefield where suitable rails have been laid), their arc of fire is very restricted and their "life" is short. _Super-Heavy Howitzers_, of 12-inch or 18-inch calibre, possess similar advantages and disadvantages to super-heavy guns. Their normal use is the destruction of permanent defences, the breaking down of bridges, etc.

The 12-inch weapon is also used on tractor-drawn mountings and is highly effective in counter-battery work.

The table on p. 173 is based upon particulars given on p. 26 of "Field Service Regulations," vol. ii. (1921).

ROYAL ENGINEERS

"All arms are responsible for the construction of their own works of defence. It is the duty of the Royal Engineers to a.s.sist them by engineer reconnaissances, plans, advice, technical supervision, provision of materials and the construction of works requiring special technical skill. . . . Although trained as fighting troops, engineers should be regarded as reserves to be used only as a last resource; casualties in their ranks are not easy to replace, and they may become needlessly involved in the fighting and lost for work which may have an important bearing on the operations" ("Field Service Regulations," vol.

ii. (1921)).

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TABLE OF ARTILLERY RANGES

Weapon Effective Range (Yds.)