POSITION WARFARE Military opinion is divided as to the likelihood of a recurrence in the future of periods of position warfare such as were experienced in the World War. Modern armies are being trained for mobile operations, but in most countries the lessons of siege warfare which were learnt between 1914 and 1918 are recorded in military text-books. A modern entrenched position consists of an elabo rate system of trenches, strong field works and barbed wire en tanglements and it is arranged in successive zones in great depth so that it cannot be penetrated by a single attack. The work of the artillery in routine trench warfare is to exhaust the enemy's strength by harassing and counter-battery fire. The tactics of the attack on a fortified position are much the same as those of the attack on a position in mobile warfare. The main points of differ ence are : (a) the details of the defences are definitely known from aerial photographs : (b) the obstacles, such as barbed wire, are more formidable; (c) the defenders will have better cover from fire in their trenches and in deep dug-outs so that the barrage and bombardment will be less effective. The first point implies that the bombardment can be concentrated on definite points, instead of being more or less spread over the country; the second requires that field guns and, if possible, tanks, must be pushed forward to cut the wire; the third entails the employment of a strong force of field and heavy artillery.
Generally speaking, the result of an attack on the grand scale depends largely on the relative strength of the forces (especially in artillery and tanks) which the combatants are able to assemble on the front attacked. If the defending commander is able to reply to the bombardment with an equally effective bombardment, and to the barrage with a counter-barrage, the enemy can gain no decisive result—by his infantry at least. Failing these assets, the defender must give ground without allowing his line to be broken, remembering that every mile of advance increases the difficulties of the attacker, till the impetus of the attack is exhausted.
French and German Tactical Doctrines.—The French doc trine is based to a great extent upon practical experience gained in the Western theatre during the World War. Special stress is laid in French military publications upon the great fire power of modern armament. Two statements in the "Instruction sur l'emploi tactique des grandes unites" will illustrate this important point. "La puissance du feu s'est affirmee ecrasante. . . L'at taque est le feu qui avance, la defense est le feu qui arrete." In practice this teaching results in a belief that attacks will generally be very costly, if not abortive, unless they are assisted by very heavy artillery support. It is considered that infantry assaults on defensive positions which are at all strong should be made only under barrages on a scale approximating to that adopted in the World War.
The German doctrine is based on the dominance of mobility, manoeuvre and surprise, and does not attach such importance to the power of fire as does the French. It is to be borne in mind, however, that the tactics of the German army must of necessity be influenced in this direction by the poverty in artillery and other mechanical arms which is at present imposed upon it by the Treaty of Versailles.
Savage Warfare.—While the general principles outlined in the foregoing sections also govern operations in undeveloped and un civilized countries, considerable modifications have to be made in the methods of their application. The difficult nature of the country and the absence of roads often make it impossible to use wheeled transport. In mountainous or bush country it is therefore usual for the bulk of the artillery to consist of light guns and howitzers which can be carried in pack. When field and medium guns can be employed, however, they are often of special value for the distant bombardment of villages and towers. The difficulties of ammunition supply are generally great and the artillery has therefore to be used economically. In savage warfare accurate large scale maps are seldom available and reliance has to be placed chiefly upon fire observed either from the ground or the air. In bush country it is usually necessary to provide escorts for all artillery both on the line of march and in action.
Gas Warfare.—Though all civilized nations have condemned the employment of poison gas in warfare it is considered necessary to take measures for defence against it and to reserve the right to freedom of action in case an enemy refuses to give an undertaking not to use it. The chemical composition and effect of such gases is described under CHEMICAL WARFARE; we are here concerned with their tactical employment by artillery.
Gas shell bombardment has, up to the present, been the most usual of the many forms of gas attack. Bombardments in the World War were of various natures according to the object in view. Short concentrated bombardments with non-persistent gas were employed with the object of inflicting casualties by surprise. In such bombardments it was necessary to fire at a rapid rate from a number of batteries simultaneously, in order to produce a strong concentration of gas so quickly that casualties would be caused before respirators could be put on. Bombardments with persistent gas, such as mustard gas, were generally used if it was desired to render certain areas of ground dangerous to occupy for considerable periods of time. A third type of bombardment took the form of harassing fire in short bursts at irregular intervals. This type of fire was employed to interfere with the hostile artil lery or to interrupt traffic and generally to reduce the efficiency of troops by compelling them to wear their masks for long inter vals. In all types of bombardment high explosive shells were fre quently used in combination with gas shells to increase disorgan ization as well as to conceal the presence of the gas as long as possible.
Gas shells require a special range table, as they are lighter than ordinary shell. They may be employed with any calibre of gun or howitzer and usually contain gas in liquid form. They are fired either entirely by map or after preliminary ranging with ordinary shell, as their impact cannot be observed. Hot sunshine causes volatile gas to disperse quickly, and a strong wind blows it away; gas is therefore most effective on a cloudy, still day. The shells are pitched to windward of the target so that the breeze will carry the gas in the required direction. In this respect guns are more effi cient than gas cylinders, as they are not obliged to await the corn ing of a favourable wind. The number of gas shells required for an effective bombardment varies according to the weather, the calibre of the piece, and the nature of the gas used, but it is al ways large, as the gas content of shells is small for their weight. The difficulty of supplying the ammunition in adequate quantities, therefore, considerably restricts the use of gas shells in mobile warfare. (See AMMUNITION ; BALLISTICS; EXPLOSIVES; ORD NANCE; for naval guns see GUNNERY, NAVAL.) (J. N. K.) the general historical works may be men tioned Napoleon III. and J. Faye, Etudes sur le passe et l'avenir de l'Artillerie, 6 vols. (1846-71) ; Die Beziehung Friedrichs des Grossen zu seiner Artillerie (1865) ; F. Duncan, History of the Royal Artillery, 2 vols. (1872, 3rd ed., 1879). A bibliography and criticism of the artillery works of the 14th century will be found in M. Jahns, Geschichte der kriegswissenschaft, in Geschichte der Wissenschaften in Deutschland (Munich, 1889-91). For the early 17th century: Ufano Diego, Tradado de la Artilleria (1613), is a standard treatise. See also Casimir Siemienowicz, Artis Magnae Artilleriae (Amsterdam, 165o, trans. by G. Shelvocke as The Great Art of Artillery, 1729) ; M. Mieth, Artilleriae recentior praxis (Frankfurt and Leipzig, 1684) ; P. Surirey de Saint-Remy, Memoires d'Artillerie, 2 vols. (1697, 3rd ed., La Haye, 1741) . From 174o: For official regulations, etc., see J. J. E. Picard and L. Jonan, L'Artillerie f rancaise au X Vllle siecle, publ. de la section historique de l'etat-ma j or de 1'armee (1906) , and for general works on the handling of the army, J. A. H. de Guibert, Essai general de tactique (1773, trans. by Lieut. Douglas, 1781), and Defense du systeme de guerre moderne ; G. J. D. von Scharnhorst, Handbuch fur Officiere, 3 bde. (Hanover, 1804-14, trans. by M. A. Fourcy as Traite sur l'Artillerie, 184o-43) . For the period 186o-1914 see Prince C. A. Hohenlohe-Ingelfingen, fiber Artillerie, vol. iii. of Militdrische Briefe (1885, trans. by N. L. Walford as Letters on Artillery, Woolwich, 1887, 3rd ed., 1889) ; J. Leurs, L'Artillerie de Campagne Prussienne de z864-'o (Brussels and Leipzig, 1874) ; E. Hennebert, Artillerie moderne (1889, end ed., 189o) . For quick-firing artillery: H. Langlois, L'Artillerie de campagne en liaison avec les autres armes (1891-92, new ed., 2 vols., 1908) ; E. von Hoffbauer, Entwickelung des Massengebrauchs der Feldartillerie (1900) ; H. A. Bethell, Modern Guns and Gunnery (Woolwich, 1905, 3rd ed. with amendments, 1910-14), and Modern Artillery in the Field (1911) ; F. Culmann, Tactique d'Artillerie; Le canon a tir rapide dans la bataille (1906, 2nd ed., 1914) ; P. Azan, Les premieres mitrailleuse, 1342-1725, publ. de la section historique de l'etat-major de l'armee (1907) ; H. Rohne, Taktik der Feldartillerie (1908, trans. by Capt. Marie as La Tactique de l'artillerie de campagne, 1908) ; Field Artillery Training, H. M. Stationery Office (1908-o9, 4th ed., 1918) ; J. Challeat, Artillerie de campagne (1909, 2nd ed., 1915) ; H. W. L. Hime, The Origin of Artillery (1915) ; D. A. Macalister, Field Gunnery (1915, 4th ed., 192o) ; F. E. Gascovin, L'Evolution de l'artillerie pendant la guerre (192o) ; Materiels Allemands et Autri chiens a grands puissance (publ. by Bercher-Lavant, Paris, 1921) ; L. Thouvenin, L'Artillerie nouvelle (1921) ; G. Bruchmuller, Die deutsche Artillerie in den Durchbruchschlachten des Weltkrieges (1921) and Die Artillerie beim Angriff im Stellungskrieg (1926) ; I. R. Campana, Les Progres de l'artillerie 1914-18 (1923) ; L. E. Babcock, Elements of Field Artillery (1925) ; Col. Duchene, Comment naquit l'artillerie de tranchee francaise (1926) .