"The rôle of artillery is to assist 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 classes 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 shell-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 aërial 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. shell 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 shell 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 classed under the designations Light, Medium, Heavy, and
Super-Heavy.
LIGHT GUNS.—Pack Guns, with a calibre of 2.75 inches, are weakest in shell-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 shell, 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 shell, are the principal artillery weapon of a field army. Although inferior in mobility to Pack or Horse Artillery, they have greater shell-power and afford the principal 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 assault. 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 shells, in neutralising an area by the use of gas shells, 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 principal 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 shell, are principally 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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