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to an 8-in. howitzer. In guns designed since the war the increase of range is very marked; thus the United States require 15,000 yd. of range for their new field gun; the latest pattern of British i8-pounder issued during the war ranged 10,800 yd., and the forthcoming pattern will probably range as far as the U.S. gun.

Hundred-Mile Guns. This general increase of range cul- minated in the German gun or rather guns (colloquially called " Big Berthas ") which shelled Paris from a distance of 76 miles. 1 As early as 1915 the Germans shelled Dunkirk from a point 25 m. distant with a i4-in. naval gun, and they proposed, if they succeeded in driving the Allies back from Calais, to use 110- mile guns which should command the whole of the British coast from Yarmouth to Southampton, and the whole of the London district. Such guns are not specially difficult to make, and both the British and the French artillery authorities had worked out the design of loo-mile guns some years before the war. In principle they depend on firing a shell upwards so as to cl|;ar the dense layer of air lying next to the earth, and to attain a height of some 25 m. where the air is so rarefied as to oppose practically no resistance to the flight of the shell. Seven of these guns were used against Paris in 1918, and at the end of the war the Germans had six more building; the British, French, and Italian Governments had each at least one of these guns building, but it is understood that none of these were com- pleted. Owing to the high powder-pressure employed, and con- sequent high temperature in the bore, the life of the German guns was only about 50 rounds, after which they had to be rebored. For this reason the too-mile gun marks about the limit of practical possibility with propellants now in use. But, if it were considered advisable, it would be possible to make a special powder giving lower temperatures than the gun-cotton and nitro-glycerine powders now in use, and so increase the life of these guns.

Flashless Powder. During " sedentary " warfare, any gun which fired at night within direct view of the enemy was liable to be marked down by the " flash-spotting " section opposite to it, who got cross bearings to it, after which it was soon shelled out. It was therefore necessary to introduce flashless powder, or else to add a portion of special chemical composition to the ordinary charge for all guns which could not be hidden behind woods or hills. The United States have specified that it is to be used in their new field gun.

Ranging by Aeroplane. Apart from the work done by air- craft in locating targets by direct observation or by photography, they were used during trench warfare for ranging on targets which could not be observed from the ground. The aeroplane was from the first fitted with a wireless sending set; but it was only towards the end of the war that practical forms of receiving apparatus were evolved, and, generally speaking, messages to the aeroplane had to be sent by code signals, which were strips of white cloth laid out on the ground near the battery. Only simple signals such as " Ready to Fire " could be used; it was therefore necessary to arrange the details as to the target to be observed beforehand. Ranging was carried out deliberately, the aeroplane sending down the result of each shot. Only one such series could be fired at a time on an army corps front, as, with the instruments then in use, if two aeroplanes had been sending wireless at the same moment they would have inter- fered with each other. Until the means of wireless communica- tion are improved, aeroplane ranging will remain too slow and elaborate a method for field artillery in mobile warfare, though it may be applied to heavy artillery.

Sound- Ranging. This is described under RANGEFINDERS AND POSITION FINDERS. It consists in measuring the intervals of time at which the sound of an enemy gun successively reaches three or more stations, and, from the differences, calculating the position of the gun. It also enables the point at which one's own shell bursts to be located. The installation of these stations

1 The bombardment of Paris was spread over 140 days; firing took place on 44 days only. 183 8-in. shell fell in Paris, and 120 in the suburbs. The material effect was slight (256 people killed in 45 months) and the moral effect, after the first day, inconsiderable.

takes about a day, and in certain conditions the method cannot be depended on or indeed used at all. In mobile warfare, sound- ranging may possibly be used to locate the enemy's heavy guns.

Warfare between Front Trenches. Simultaneously with the long-distance shooting at targets behind the fronts, constant fighting took place between the front trenches, which, early in the war, were in some places only 50 yd. apart. Even when the front trenches were shifted back behind screens of defensive points, constant guerrilla warfare continued to be waged between the detachments opposite" each other. The need for trench artillery was soon felt, and was supplied by a new class of weapon. The original trench mortars had only a very short range, and, as they had therefore to be kept close up to the front trench, the loss of life among the detachments was heavy. Later, longer- ranging trench mortars were introduced, which could be posted relatively far back, and were available for firing on our own front trench if the enemy broke into it.

Trench ordnance on wheeled mounts was used to some extent as accompanying artillery, especially the later pattern of the German light trench mortar, which was fitted for direct as well as for high-angle fire. But the excessive weight of the ammuni- tion renders trench mortars unsuitable as substitutes for guns of accompaniment.

Wire-Cutting. Very early in the war it became necessary to find a means of destroying, or at least cutting lanes in the strong barbed wire entanglements which covered the whole front. At the period of the autumn battles of 1915, this was done on the British front by the shrapnel fire of field guns. This was effective for wire-cutting only up to about 1,800 yd.; within that range it was found that lanes could be cut through a belt of wire 8 yd. deep with an expenditure not exceeding 10 rounds per yd. of front. Later on, thick steel barbed wire came into use, which could not be cut by shrapnel bullets; moreover, the process of wire-cutting with shrapnel required precise and deliberate shooting, and had usually to be carried out on the day before the attack, thus forfeiting the advantage of surprise. Howitzer H.E. shell with ordinary fuzes proved useless, as. they made craters into which the network of wire fell back, making a worse obstacle than before. In 1916 medium trench- mortar shell with instantaneous fuze came- into use; these shell made a crater not more than 6 in. deep, and blew away the wire from a circle about 5 yd. in diameter. But trench mortar ranges are very limited and it was not till the instantaneous fuze was adapted to H.E. shell for field guns and field howitzers that the range at which wire could be cut was increased to 4,000 yards. The French used the 75-mm. field gun, while the British mostly used the 4'5-in. field howitzer. As an alternative to the instantaneous fuze, a percussion fuze giving a slight delay action was used with H.E. shell for wire-cutting, the object being to burst the shell on the upward branch of its trajectory after impact, withirt a yard or so of the ground. Some success was attained with this method when the ground was hard and the angle of impact small, so that the shell did not tend to bury itself. Wire-cutting with H.E. shell is a much quicker method than with carefully adjusted shrapnel bursts, provided that a sufficient volume of fire is obtainable (see section EFFECT supra).

Counter-Battery work is the attack of artillery by artillery with the object of destroying the material and inflicting disabling casualties, or at least of neutralizing enemy fire for a certain time. In spite of the results achieved in locating enemy guns by aircraft, flash-spotting, and sound-ranging, counter-battery work throughout the war generally failed to destroy them and their detachments, or even to silence them permanently. How- ever, when a battery was located it was usually possible to neutralize it, that is, to stop or much reduce its fire, so long as fire upon it could be kept up.

If a battery exposed itself in the open within range of artillery in position it was destroyed in a few minutes. Therefore bat- teries used concealed and camouflaged positions with overhead cover proof against field artillery. If such a position was located the battery was soon shelled out by the 6-in. and heavier howit- zers, but it was rarely possible to destroy the guns without an