_Light Artillery_ H.E. Sh.e.l.l Shrapnel Pack Guns (2.75 in.) 5,800 4,000 Pack Howitzers (3.7 in.) 5,900 Horse Artillery Guns (13 pr.) 8,500 5,000 Field Guns (18 pr.) 9,500 5,500 Field Howitzers (4.5 in.) 7,000

_Medium Artillery_ Medium Guns (60 pr.) 15,500 -- Medium Howitzers (6 in.) 10,000

_Heavy Artillery_ Heavy Guns (6 in.) 19/20,000 Heavy Howitzers (8 in.) 12,300 -- " " (9.2 in) 13,000

_Super-Heavy Artillery_ Super-Heavy Guns (9.2 in.) 24,500 -- " " (12 in.) 28,200 -- " " (14 in.) 35,600 -- Super-Heavy Howitzers (12 in.) 14,300 " " (18 in) 23,000

Weapon Maximum Range (Yds.)

_Light Artillery_ H.E. Sh.e.l.l Shrapnel Pack Guns (2.75 in.) 5,800 5,500 Pack Howitzers (3.7 in.) 5,900 Horse Artillery Guns (13 pr.) 8,500 6,400 Field Guns (18 pr.) 9,500 6,500 Field Howitzers (4.5 in.) 7,000

_Medium Artillery_ Medium Guns (60 pr.) 15,500 15,300 Medium Howitzers (6 in.) 10,000

_Heavy Artillery_ Heavy Guns (6 in.) 19/20,000 19/20,000 Heavy Howitzers (8 in.) 12,300 " " (9.2 in) 13,000

_Super-Heavy Artillery_ Super-Heavy Guns (9.2 in.) 24,500 24,500 " " (12 in.) 28,200 26,100 " " (14 in.) 35,600 -- Super-Heavy Howitzers (12 in.) 14,300 " " (18 in) 23,000

The maximum range of _Medium Mortars_ is 1,500 yards; of _Light Mortars_ 700 yards.

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CAREY'S FORCE.--During the _Second Battle of the Somme_ "a mixed force, including details, stragglers, schools personnel, tunnelling companies, army troops companies, field survey companies, and Canadian and American Engineers, had been got together and organised by Major-Gen.

P. G. Grant, the Chief Engineer to the V. Army. On March 26 these were posted by General Grant, in accordance with orders given by the V. Army commander, on the line of the old Amiens defences between Mezieres, Marcelcave, and Hamel. Subsequently, as General Grant could ill be spared from his proper duties, he was directed to hand over command of his force to Major-Gen. G. G. S. Carey. Except for General Carey's force there were no reinforcements of any kind behind the divisions, which had been fighting for the most part since the opening of the battle. . . . On March 28 our line from Marcelcave to the Somme was manned by Carey's Force, with the 1st Cavalry Division in close support. . . . On March 29 the greater part of the British front south of the Somme was held by Carey's Force, a.s.sisted by the 1st Cavalry Division and such troops of the divisions originally engaged as it had not yet been found possible to withdraw. In rear of these troops, a few of the divisions of the V. Army were given a brief opportunity to rea.s.semble" (Sir D. Haig's Dispatches).

TANKS

Tanks are moving fortresses containing light artillery, machine guns, and rifles, and while capable of inflicting heavy losses by fire they can also destroy obstacles, weapons, and personnel. Their garrisons are protected against the fire of small arms and from shrapnel bullets, but they are very vulnerable to other forms of artillery fire. Their mobility and radius of action are governed by the amount of petrol carried and by the physical endurance of the crew, but except over deep cuttings, {175} broad streams, swamps, very heavily sh.e.l.led ground, rocky and mountainous country, or in thick woods they can move without difficulty. "The power of delivering successful surprise attacks against almost any type of defences is one of the most important advantages of the use of Tanks in large numbers" ("Field Service Regulations," vol. ii. (1921)).

During the _First Battle of the Somme_ (September 1-November 18, 1916) "Our new heavily armoured cars, known as 'Tanks,' now brought into action for the first time, successfully co-operated with the infantry, and coming as a surprise to the enemy rank and file, gave valuable help in breaking down their resistance. . . . These cars proved of great value on various occasions, and the personnel in charge of them performed many deeds of remarkable valour" (Sir D. Haig's Dispatches).

AIRCRAFT

Two cla.s.ses of Aircraft are used in the field. Aeroplanes, which are self-propelled and have an almost unlimited radius of action; and Kite Balloons, which, in favourable weather, can be towed by a lorry and can be moved frequently without loss of efficiency.

AEROPLANES are of the greatest value for reconnaissance and inter-communication, and not only obtain, and return to their base with, information of the highest value, but facilitate personal reconnaissance of the battlefield by commanders and staff officers.

Their offensive and defensive action is also very great and the moral effect of their offensive action is of the highest value. Although aeroplane squadrons are mobile units they lose efficiency if the units are moved too frequently. The action of aircraft in various phases of fighting is dealt with throughout the Lectures.

KITE BALLOONS carry two observers, who can remain in telephonic communication with the ground up to a {176} height of 5,000 feet.

Inflated balloons can be moved in favourable weather at a maximum speed of 8 miles an hour while at a height of about 500 feet. Their extreme vulnerability to artillery fire prevents their use close to the battle front.

GAS

"The advisability of employing gas as a military weapon is a matter for consideration by the authorities concerned before a campaign begins.

Once authorised, however, and a.s.suming that weather conditions are favourable, gas may be expected to play a part in every action. . . .

The different methods in which gas can be employed make it a weapon which can be used by all arms, thus _Artillery_ deal with gas sh.e.l.ls, _Infantry_ with light mortar gas bombs, _Aircraft_ with aerial gas bombs, and _Engineers_ with all methods of use that call for special manipulation" ("Field Service Regulations," vol. ii. (1921)).

Gas was introduced by the Germans during the _Second Battle of Ypres_ (April 22-May 18, 1915), and the numerous experiments and trials necessary before gas can be used, and the great preparations which have to be made for its manufacture, show that its employment was not the result of a desperate decision, but had been prepared for deliberately.

During the _First Battle of the Somme_ (September 1-November 18, 1916) "the employment by the enemy of gas and liquid flame as weapons of offence compelled us not only to discover ways to protect our troops from their effects, but also to devise means to make use of the same instruments of destruction. . . . Since we have been compelled, in self-defence, to use similar methods, it is satisfactory to be able to record, on the evidence of prisoners, of doc.u.ments captured, and of our own observation, that the enemy has suffered heavy casualties from our gas attacks, while the means of protection adopted by us {177} have proved thoroughly effective" (Sir D. Haig's Dispatches).

SMOKE

Smoke can be discharged from _Artillery_ sh.e.l.ls, Artillery or _infantry_ mortar bombs, Infantry rifle grenades, smoke candles, _Aircraft_ bombs, _Engineers'_ stationary generators, or the exhaust pipe of _Tanks_. It is used to conceal movement for the purposes of surprise or for reducing casualties, and can be so employed as to impose night conditions on the enemy while one's own troops retain the natural visibility; but while the weight and direction of an intended blow may thus be hidden from the enemy a warning is given of the time of its delivery. It is possible, however, to mystify, as well as to surprise, the enemy by the use of smoke, and its strategical and tactical value will ensure its adoption in Modern Warfare. In the closing battles of the Great War "the use of smoke sh.e.l.ls for covering the advance of our infantry and masking the enemy's positions was introduced and employed with increasing frequency and effect" (Sir D.

Haig's Dispatches).

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OPERATION ORDERS

Combatant officers of every rank are required to issue orders of some kind or other, and orders for operations should always be committed to paper when circ.u.mstances permit. The object of an operation order is to bring about a course of action in accordance with the intentions of the commander, and with full co-operation between all units.

Operation orders of a complicated nature are unlikely to be required from the pen of infantry officers in the junior ranks, and the rules for drafting orders are stated in detail in the official text-books, for the use of officers of the ranks that will be required to issue them.

The general principles underlying orders of all kinds are that they should be "fool proof," and it has been remarked that the writer of orders should always remember that at least one silly a.s.s will try to misunderstand them. They must, therefore, be void of all ambiguity, and while containing every essential piece of information, and omitting everything that is clearly known already to the recipients, they should be confined to facts, and conjecture should be avoided.

"An operation order must contain just what the recipient requires to know and nothing more. It should tell him nothing which he can and should arrange for himself, and, especially in the case of large forces, will only enter into details when details are absolutely necessary. Any attempt to prescribe to a subordinate at a distance anything which he, with a fuller knowledge of local conditions, should be better able to decide on the spot, is likely to cramp his initiative in dealing with unforeseen developments, and will be avoided. In {179} particular, such expressions as 'Will await further orders' should be avoided" ("Field Service Regulations," vol. ii. (1921)).

Apart from the standing rules as to the printing of names of places in block type, including a reference to the map used, dating and signing the orders, numbering the copies, and stating the time and method of issue, etc., the general tenour of all operation orders will always be: _The enemy are. . . . My intention is. . . . You will. . . ._ In other words, all that is known about the enemy, and of our own troops, that is essential for the purposes of the order, should be revealed; then the general intention of the commander who issues the orders; then the part in the operations that is to be played by the recipient. But the method of attaining the object will be left to the utmost extent possible to the recipient, with due regard to his personal characteristics. "It is essential that subordinates should not only be able to work intelligently and resolutely in accordance with brief orders or instructions, but should also be able to take upon themselves, whenever necessary, the responsibility of departing from, or of varying, the orders they may have received" ("Field Service Regulations," vol. ii. (1921)).