13.Artillery, 1815-1865.—Henceforward, therefore, the history of artillery becomes the history of its technical effectiveness, particularly in relation to infantry fire, and of improvements or modifications in the method of putting well-recognized principles into action. Infantry fire, however, being more variable in its effectiveness than that of artillery, the period 1815-1870 saw many changes in the relations of the two arms. In the time of Napoleon, infantry fire never equalled that of the Seven Years’ War, and after the period of the great wars the musket was less and less effectively used. Economy was, however, practised to excess in every army of Europe during the period 1815-1850, and even if there had been great battles at this time, the artillery, which was maintained on a minimum strength of guns, men and horses, would not have repeated the exploits of Sénarmont and Drouot in the Napoleonic wars. The principle was well understood, but under such conditions the practice was impossible. It was at this stage that the generalintroduction of the rifled musket put an end, once for all, to the artillery tactics of the smooth-bore days. Infantry, armed with a far-ranging rifle, as in the American Civil War, kept the guns beyond case-shot range, compelling them to use only round shot or common shell. In that war, therefore, attacking infantry met, on reaching close quarters, not regiments already broken by afeu d’enfer, but the full force of the defenders’ artillery and infantry, both arms fresh and unshaken, and the full volume of their case shot and musketry. At Fredericksburg the Federal infantry attacked, unsupported by a single field piece; at Gettysburg the Federal artillery general Hunt was able to reserve his ammunition to meet Lee’s assault, although the infantry of his own side was meanwhile subjected to the fire of 137 Confederate guns. Thus, in both these cases the assault became one of infantry against unshaken infantry and artillery. On many occasions, indeed, the batteries on either side went into close ranges, as the traditions of the old United States army dictated, but their losses were then totally out of proportion to their effectiveness. Indeed, the increased range at which battles were now fought, and the ineffectiveness of the projectiles necessarily used by the artillery at these ranges, so far neutralized even rifled guns that artillery generals could speak of “idle cannonades” as the “besetting sin” of some commanders.
14.The Franco-German War, 1870-71.—In the next great war, that of 1866 (Bohemia), guns were present on both sides in great numbers, the average for both sides being three guns per 1000 men. Artillery, however, played but a small part in the Prussian attacks, this being due to the inadequate training then afforded, and also to the mixture of rifled guns and smooth-bores in their armament. In Prussia, however, the exertions of General v. Hindersin, the improvement of thematériel, and above all the better tactical training of the batteries, were rewarded four years later by success on the battlefield almost as decisive as Napoleon’s. In 1870 the French artillery was invariably defeated by that of the Germans, who were then free to turn their attention to the hostile infantry. At first, indeed, the German infantry was too impatient to wait until the victorious artillery had prepared the way for them by disintegrating the opposing line of riflemen. Thus the attack of the Prussian Guards at St Privat (August 18, 1870) melted away before the unbroken fire-power of the French, as had that of the Federals at Fredericksburg and that of the Confederates at Gettysburg. But such experiences taught the German infantry commanders the necessity of patience, and at Sedan the French army was enveloped by the fire of nearly 600 guns, which did their work so thoroughly that the Germans annihilated the Imperial army at the cost of only 5% of casualties.
15.Results of the War.—The tactical lessons of the war, so far as field artillery is concerned, may be briefly summarized as (a) employment of great masses of guns; (b) forward position of guns in the order of march, in order to bring them into action as quickly as possible; (c) the so-called “artillery duel,” in which the assailant subdues the enemy’s artillery fire; and (d) when this is achieved, and not before, the thorough preparation of all infantry attacks by artillery bombardment. This theory of field artillery action has not, even with the almost revolutionary improvements of the present period, entirely lost its value, and it may be studied in detail in the well-known work of von Schell,Taktik der Feldartillerie(1877), later translated into English by Major-General Sir A.E. Turner (Tactics of Field Artillery, 1900). In one important matter, however, the precepts of Schell and his contemporaries no longer hold good. “It is absolutely necessary that the object of the infantry’s attack should be cannonaded before it advances. To accomplish this, sufficient time should be given to the artillery, and on no account should the infantry be ordered to advance until the fire of the guns has produced the desired effect.” This, the direct outcome of the slaughter at St Privat, represents the best possibilities of breech-loading guns with common shell—no more than a slow disintegration of the enemy’s power of resistance by a thorough and lengthy “artillery preparation.” Against troops sheltered behind works (as in the Russo-Turkish War of 1877-78) the common shell usually failed to give satisfactory results, if for no other reason, because the “preparation” consumed an inordinate time, and in any case the hostile artillery had first of all to be subdued in the artillery duel.
16.Quick-firing Field Guns.—In 1891, a work by General Wille of the German army (The Field Gun of the Future) and in 1892 another by Colonel Langlois of the French service (Field Artillery with the other Arms) foreshadowed many revolutionary changes inmatérieland tactics which have now taken place. The new ideas spread rapidly, and the quick-firing gun came by degrees to be used in every army. The original designs have been greatly improved upon (seeOrdnance:Field artillery equipments), but the principles of these designs have not undergone serious modification. These are, briefly, the mechanical absorption of the recoil, by means of brakes or buffers, and the development of “time shrapnel” as the projectile of field artillery. The absorption of recoil of itself permits of a higher rate of fire, since the gun does not require to be run up and relaid after every shot. Formerly such an advantage was illusory (since aim could not be taken through the thick bank of smoke produced by rapid fire), but the introduction of smokeless powder removed this objection. Artillerists, no longer handicapped, at once turned their attention to the increase of the rate of fire. At the same time a shield was applied to the gun, for the protection of the detachment. This advantage is solely the result of the non-recoiling carriage. The gunners had formerly to stand clear of the recoiling gun, and a shield was therefore of but slight value.
17.Time Shrapnel.—The power of modern artillery owes even more to the improvement of the projectile than to that of the gun (seeAmmunition). The French, always in the forefront of artillery progress, were the first nation to realize the new significance of the time-fuze and the shrapnel shell. These had been in existence for many years; to the British army are due both the invention and the development of the shrapnel, which made its first appearance in European warfare at Vimeira in 1808. But, up to the introduction of rifled pieces, the Napoleonic case-shot attack was universally and justly considered the best method of fighting, and in the transition stage of thematérielmany soldiers continued to put faith in the old method,—hence the Prussian artillery in 1866 had many smooth-bore batteries in the field,—and between 1860 and 1870 gunners, now convinced of the superiority of the new equipments, undoubtedly sought to turn to account the minute accuracy of the rifled weapons in unnecessarily fine shooting. Thus, in 1870 the French time-fuze was only graduated for two ranges, and the Germans used percussion fuzes only. But this phase has passed, and General Langlois has summarized the tactics of the newest field artillery in one phrase: “It results in transferring to 3000 yds. the point-blank and case-shot fire of the smooth-bore.” The meaning of this will be discussed later; here it will be sufficient to say that it is claimed for the modern gun and the modern shell that the Napoleonic method1of annihilating by a rain of bullets has been revived, with the distinction that the shell, and not the gun, fires the bullets close up to the enemy. In the Boer War, Pieter’s Hill furnished a notable example of this “covering,” as distinct from “preparation,” of an assault by artillery fire.
18.Heavy Field, Siege and Garrison Artillery.—Amongst other results of this war was a recrudescence of the idea of “dispersion.” This will be noticed later; the more material result of the Boer War, and of the generally increasing specialization in the various functions of the artillery arm, has been the reintroduction of heavy ordnance into field armies. The field howitzer reappeared some time before the outbreak of that war, and the British howitzers had illustrated their shell-power in the Sudan campaign of 1898. During the latter part of the 19th century, siege and fortress artillery underwent a development hardly less remarkable than that of field artillery in the same time. Rifled guns, “long” and “short” for direct and curved fire, formed the siege artillery of the Germans in 1870-71, andwith the reduction of the old-fashioned fortresses of France began a new era in siegecraft (seeFortification and Siegecraft). At the present time howitzers2(B.L. rifled) are the principal siege weapons, while heavy direct-fire guns (seeOrdnancepassim) still retain a part of the work formerly assigned to the artillery of the attack. For an account of a siege with modern artillery see Macalik and Länger,Kampf um eine Festung, which describes an imaginary siege of Königgrätz. On the whole, it may be said that modern artillery has caused a revolution in methods of fortification and siegecraft, which is little less far-reaching than the original change from the trébuchet to the bombard.
Organization
19.Field Artillery Organization.—Abatteryof field artillery comprises three elements, viz.matériel,—guns, carriages, ammunition and stores;personnel,—officers, non-commissioned officers, gunners, drivers and artificers; andtransport,—almost invariably horses, though other animals, and also motor and mechanical transport, are used under special circumstances. As for thematériel, the guns used by field artillery in almost all countries are quick-firers, throwing shells of 13 to 18 pounds; details of these will be found in the articleOrdnance. The number of guns in a battery varies in different countries between four and eight; by far the most usual number is six. With the introduction of the quick-firing gun, the tendency towards small batteries (of four guns) has become very pronounced, the ruling motives being (a) better control of fire in action, and (b) more horses available to draw the increased number of ammunition wagons required. “Mixed” batteries of guns and howitzers were formerly employed on occasion, and were supposed to be adapted to every kind of work. However, the difference between the gun and the howitzer was so great that at all times one part of the armament was idle, while the general increase in the artillery arm has permitted batteries and brigades of howitzers to be formed, separately, as required. Machine guns (q.v.) are not treated in Great Britain as being artillery weapons, though abroad they are often organized in batteries. During, and subsequent to the Boer War, heavier machine guns, called pompoms, came into use. The rocket (q.v.), formerly a common weapon of the artillery, is now used, if at all, only for mountain and forest warfare against savages.
20.Ammunition.—The vehicles of a battery include (besides guns and limbers) ammunition wagons, store and provision carts or wagons and forage wagons. On the amount of ammunition that should be carried with a field battery there was formerly a considerable diversity of opinion. The greater the amount a battery carries with it, the more independent it is; on the other hand, every additional wagon makes the battery more cumbrous and, by lengthening out the column, keeps back the combatant troops marching in rear. But since the introduction of the Q.F. gun it has been universally recognized that the gun must have a very liberal supply of ammunition present with it in action, and the old standard allowance of one wagon per gun has been increased to that of two and even three. Formerly batteries were further hampered by having to carry the reserve of small-arm ammunition for infantry and cavalry. But the greater distances of modern warfare accentuate the difficulties of such a system, and the reserve ammunition for all arms is now carried in special “ammunition columns” (seeAmmunition), thepersonneland transport of which is furnished by the artillery.
21.Interior Economy.—The organization and interior economy of a battery is much the same in all field artillery. In England the command is held by a major, the second in command is a captain. The battery is divided into three “sections” of two guns each, each under a subaltern officer, who is responsible for everything connected with his section—men, horses, guns, carriages, ammunition and stores. Each section again consists of two sub-sections, each comprising one gun and its wagons, men and horses, and at the head of each is the “No. 1” of the gun detachment—usually a sergeant—who is immediately responsible to the section commander for his sub-section.
The No. 1 rides with the gun, there is also another mounted non-commissioned officer who rides with the first wagon, and the gunners are seated on the gun-carriage, wagon and limbers. The increased number of wagons now accompanying the gun has, however, given more seating accommodation to the detachment, and this distribution has in some cases been altered. The three drivers ride the near horses of their respective pairs, each gun and each wagon being drawn by six horses. On the march, the gun is attached to the limber, a two-wheeled carriage drawn by the gun team; the wagon consists likewise of a “body” and a limber. A battery has also a number of non-combatant carriages, such as forge and baggage wagons. In addition to the gunners and drivers, there are men specially trained in range-taking, signalling, &c., in all batteries.
22.Special Natures of Field Artillery.—Horse Artillerydiffers from field in that the whole gun detachment is mounted, and the gun and wagon therefore are freed from the load of men and their equipment. The organization of a battery of horse artillery differs but slightly from that of a field battery; it is somewhat stronger in rank and file, as horse-holders have to be provided for the gunners in action. Horse artillery is often lightened, moreover, by sacrificing power (seeOrdnance). The essential feature ofMountain Artilleryin general is the carrying of the whole equipment on the backs of mules or other animals. The total weight is usually distributed in four or five mule-loads. For action the loads are lifted off the saddles and “assembled,” and the time required to do this is, in well-trained batteries, only one minute. For the technical questions connected with the gun and its carriage, seeOrdnance. The weight of a shell in a mountain gun rarely exceeds 12 ℔, and is usually less. In most armies thefield howitzerhas, after an eclipse of many years, reasserted its place. The weapons used are B.L. or Q.F. howitzers on field carriages; the calibre varies from about 4 to 5 in. In Great Britain the field howitzer batteries are organized as, and form part of, the Royal Field Artillery, two batteries of six howitzers each forming a brigade.
23.Heavy Ordnance.—Heavy Field Artillery, officially defined as “all artillery equipped with mobile guns of 4-in. calibre and upwards,” is usually composed, in Great Britain, of 5-in. or 4.7-in. Q.F. guns on field carriages. 6-in. Q.F. guns have also been used. A battery (4 guns) is attached to the divisional artillery of each division, a company of the Royal Garrison Artillery furnishing thepersonnel. The four guns are divided into two sections, each section under an officer and each subsection under a non-commissioned officer, as in the horse and field batteries.Siegeandgarrison artilleryhave not usually the complete and permanent organization that distinguishes field artillery. For siege trains thematérielis usually kept in store, and thepersonneland transport are supplied from other sources according to requirement. In garrison artillery, the guns mounted in fortresses and batteries, or stored in arsenals for the purpose, furnish thematériel, and the companies of garrison artillery thepersonnel. In Great Britain, the Royal Garrison Artillery finds the mountain batteries and the heavy field artillery in addition to its own units. The siege trains are, as has been said, organizedad hocon each particular occasion (seeFortification and Siegecraft). In Great Britain, the guns and howitzers manned by the R.G.A. would be 6-in. and 8-in. howitzers, 4.7-in. and 6-in. guns, and still heavier howitzers, as well as the field and heavy batteries belonging to the divisions making the siege.
24.Higher Organization of Artillery.—The higher units, in almost every country except Great Britain, are the regiment, and, sometimes, the brigade of two or more regiments. These units are distributed to army corps, divisions and districts, in the same way as units of other arms (seeArmy). In Great Britain the Royal Regiment of Artillery still comprises the wholepersonnelof the arm, being divided into the Royal Horse, Royal Field and Royal Garrison Artillery; to each branch SpecialReserve and Territorial artillery are affiliated. Over and above the military command of these higher units, provision is usually made for technical control of thematériel, and a variety of training and experimental establishments, such as schools of gunnery, are maintained in all countries. The more special unit of organization in mobile artillery is thebrigade, formerly called brigade-division (German,Abteilung; Frenchgroupe). The brigade is in Great Britain the administrative and tactical unit. Mountain artillery is not organized in brigades in the British empire. The unit consists, in the case of guns, of three batteries (18 guns, heavy artillery 12), in the case of field howitzers of two batteries (12 howitzers), and in the horse artillery of two batteries (12 guns), and is commanded by a lieutenant-colonel. To each brigade is allotted an ammunition column. The necessity for such a grouping of batteries will be apparent if the reader notes that 54 field guns, 12 howitzers and 4 heavy field guns form the artillery of a single British division of about 15,000 combatants.
25.Grouping of the Artillery.—The “corps artillery” (formerly the “reserve artillery”) now consists only of the howitzer and heavy brigades, with a brigade of horse artillery. The latter is held at the disposal of the corps commander for the swift reinforcement of a threatened point; the howitzers and the heavy guns have, of course, functions widely different from those of the mass of guns. As the field artillery is required to come into action at the earliest possible moment, it has now been distributed amongst the infantry divisions, and marches almost at the head of the various combatant columns, instead of being relegated perhaps to the tail of the centre column. The redistribution of the British army (1907) on a divisional basis is a remarkable example of this; even the special natures of artillery (except horse artillery) are distributed amongst the divisions. In Germany two “regiments” (each of 2Abteilungen= 6 batteries) form a brigade, under an artillery general in each division who thus disposes of 72 field guns, and the howitzers, with such horse artillery batteries as remain over after the cavalry has been supplied, still form a corps or reserve artillery. In 1903 the French, after long hesitation, assigned the whole of the field artillery to the various divisions, but later (for reasons stated in the articleTactics) arranged to reconstitute the old-fashioned corps artillery in war. (See alsoArmy, § 49).
Tactical Work
26.General Characteristics of Field Artillery Action.—The duty of field artillery in action is to fire with the greatest effect on the target which is for the moment of the greatest tactical importance. This definition of field artillery tactics brings the student at once to questions of combined tactics, for which consult the articleTactics. The purpose of the present article is to indicate the methods employed by the gunners to give effect to their fire at the targets mentioned. For this purpose the artillery has at its disposal two types of projectile, common (or rather, high explosive) shell and shrapnel, and two fuzes, “time” and “percussion” (seeAmmunition). The actual process of coming into action may be described in a few words. The gun is, at or near its position in action, “unlimbered” and the gun limber and team sent back under cover. Ammunition for the gun is first taken from the wagon that accompanies it, as it is very desirable to keep the limbers full as long as possible, in case of emergencies such as that of a temporary separation from the wagon. Limber supply is, however, allowed in certain circumstances. The wagon is now placed as a rule by the side of the gun, an arrangement which immensely simplifies the supply of ammunition, this being done under cover of the armour on the wagon and of the gun-shield and also without fatigue to the men. The older method of placing the wagon at some distance behind the gun is still occasionally used, especially in the case of unshielded equipments. No horses are allowed, in any case, to be actually with the line of guns. According to the BritishField Artillery Trainingof 1906, a battery in action would be thus distributed: first, the “fighting battery” consisting of the six guns, each with its wagon alongside, and the limbers of the two flank guns; then, under cover in rear, the “first line of wagons” comprising the teams of the fighting battery, the four remaining gun limbers, and six more wagons. The non-combatant vehicles form the “second line of wagons.”
27.Occupation of a Position.—This depends primarily upon considerations of tactics, for the accurate co-operation of the guns is the first essential to success in the general task. In details, however, the choice of position varies to some extent with the nature of the equipment: for instance, an elevated position is better adapted than a low one for high velocity guns firing over the heads of their own infantry, and again, the “spade” with which nearly all equipments are furnished (seeOrdnance) should have soil in which it can find a hold. Cover for the gun and its detachment cannot well be obtained from the configuration of the ground, because, if the gun can shoot over the covering mass of earth, the hostile shells can of course do likewise. Sufficient protection is given by the shield, and thus “cover” for field-guns simply means concealment. Cover for the “first line of wagons” is, however, a very serious consideration. As to concealment, it is stated that “the broad white flash from a gun firing smokeless powder is visible” to an enemy “unless the muzzle is at least 10 ft. below the covering crest” (Bethell,Modern Guns and Gunnery, 1907, p. 147). Concealment therefore, means only the skilful use of ground in such a way as to make the enemy’s ranging difficult. This frequently involves the use of retired positions, on reverse slopes, in low ground, &c., and in all modern artillery the greatest stress is laid on practice in firing by indirect means. Controversy has, however, arisen as to whether inability to see the foreground is not a drawback so serious that direct fire from a crest position, in spite of its exposure, must be taken as the normal method. The latter is of course immensely facilitated by the introduction of the shield. A great advantage of retired positions is that, provided unity of direction is kept, an overwhelming artillery surprise (seeF. A. Training, 1906, p. 225) is carried out more easily than from a visible position. The extent offrontof a battery in action is governed by the rule that no two gun detachments should be exposed to being hit by the bullets of one shell, and also by the necessity of having as many guns as possible at work. These two conditions are met by the adoption of a 20-yards interval between the muzzles of the guns. At the present time the gun and its wagon are placed as close together as possible, to obtain the full advantage of the armoured equipment. Theshield, behind which the detachments remain at all times covered from rifle (except at very short range) and shrapnel bullets,3enables the artillery commander to handle his batteries far more boldly than formerly was the case. General Langlois says “the shield-protected carriage is the corollary to the quick-firing gun.” Armour on the wagon, enabling ammunition supply as well as the service of the gun, to be carried on under cover, soon followed the introduction of the shield. The disadvantage of extra weight and consequently increased difficulty of “man-handling” the equipment is held to be of far less importance than the advantages obtained by the use of armour.
28.Laying.—“Elevation” may be defined as the vertical inclination of the gun, “direction” as the horizontal inclination to the right or left, necessary to direct the path of the projectile to the object aimed at. “Laying” the gun, in the case of most modern equipments, is divided, by means of the device called the independent line of sight (seeOrdnance), into two processes, performed simultaneously by different men, the adjustment of the sights and that of the gun. The first is the act of finding the “line of sight,” or line joining the sights and the point aimed at; for this the equipment has to be “traversed” right or left so as to point in the proper direction, and also adjusted in the vertical plane. The simplest form of laying for direction, or “line,” is called the “direct” method. If the point aimed at is the target, and it can be seen by the layer, he has merely to look over the “open” sights. But the point aimed at is rarely the target itself. In war, the target, even if visible, is often indistinct,and in this case, as also when the guns are under cover or engaging a target under cover, an “aiming point” or “auxiliary mark,” a conspicuous point quite apart and distinct from the target, has to be employed (“indirect” method). In the Russo-Japanese War the sun was sometimes used as an aiming point. When the guns are behind cover and the foreground cannot be seen, an artificial aiming point is often made by placing a line of “aiming posts” in the ground. If an aiming point can be found which is in line with the target, as would be the case when aiming posts are laid out, the laying is simple, but it is as often as not out of the line. Finding the “line” in this case involves the calculation, from a distant observing point, of the angle at which the guns must be laid in order that, when the sights are directed upon the aiming point, the shell will strike the target. It is further necessary to find the “angle of sight” or inclination of the line of sight to the horizontal plane. If aim be taken over the open sights at the target, the line of sight naturally passes through the target, but in any other case it may be above or below it. Then the point where the projectile will meet the line of sight, which should coincide with the target, is beyond it if the line of sight is below or angle of sight is too small, and short of it if the line of sight is too high—that is, range and fuze will be wrong. The process of indirect laying for elevation therefore is, first, the measurement of the angle of sight, and secondly, the setting of the sights to that angle by means of a clinometer; this is called clinometer laying. In all cases the actual elevation of the gun to enable the shell to strike the target is a purely mechanical adjustment, performed independently; the gun is moved relatively to the sights, which have been previously set as described. Frequently the battery commander directs the guns from a point at some distance, communication being maintained by signallers or by field telephone. This is the normal procedure when the guns are firing from cover. Instruments of precision and careful calculations are, of course, required to fight a battery in this manner, many allowances having to be made for the differences in height, distance and angle between the position of the battery commander and that of the guns.
29.Ranging4(except on the French system alluded to below) is, first, finding the range (i.e.elevation required), and secondly, correcting the standard length of fuze for that range in accordance with the circumstances of each case. To find the elevation required, it is necessary to observe the bursts of shells “on graze” with reference to the target. The battery commander orders two elevations differing by 300 yds.,e.g.“2500, 2800,” and tells off a “ranging section” of two guns. These proceed to fire percussion shrapnel at the two different elevations, in order to obtain bursts “over” (+) and “short” (−). When it is certain that this “long bracket” is obtained, the “100 yds. bracket” is found, the elevations in the given case being, perhaps, 2600 and 2700 yds. “Verifying” rounds are then fired, to make certain of the 100 yds. bracket. The old “short bracket” (50 yds.) is not now required except at standing targets. Circumstances may, of course, shorten the process; for instance, a hit upon the target itself could be “verified” at once. The determination of the fuze (by time shrapnel) follows. The fuze has a standard length for the ascertained range, but the proper correction of this standard length to suit the atmospheric conditions has to be made. The commander has therefore already given out a series of corrector5lengths, his object being to secure bursts both in air and on graze. When he is finally satisfied he opens fire “for effect.”
30. An example of the ordinary method of ranging, adapted fromField Artillery Training, 1906, is given below.
Battery commander gives target, &c., and orders: “Right section ranging section; remainder corrector 150 increase 10, 4400-4700,” for the long bracket.No. 1 gun fires, elevation 4400 yds., P.S., round observed −No. 2 gun fires, elevation 4700 yds., P.S., round observed +B.C.orders “4500-4600.”No. 1 gun fires, elevation 4500 yds., P.S., round observed −No. 2 gun fires, elevation 4600 yds., P.S., round observed +The 100 yds. bracket appears to be 4500-4600.B.C.orders: “Remainder 4500 time shrapnel,” and gives the ranging section 4500-4600 to “verify.” Guns 3, 4, 5, 6 set fuzes for 4500 with correctors 150, 160, 170, 180.No. 1 gun fires, elevation 4500 yds., P.S., round observed −No. 2 gun fires, elevation 4600 yds., P.S., round observed +B.C.orders: “Remainder 4500, one round gun fire, 3 seconds.”No. 3 elevation 4500 yds. T.S. corrector 150 airNo. 4 elevation 4500 yds. T.S. corrector 160 airNo. 5 elevation 4500 yds. T.S. corrector 160 grazeNo. 6 elevation 4500 yds. T.S. corrector 180 grazeB.C.selects corrector 160 and goes to “section fire.”The battery now begins to fire “for effect.”No. 1 elevation 4500 yds. T.S. corrector 160 airNo. 3 elevation 4500 yds. T.S. corrector 160 airfollowed by Nos. 5, 2, 4 and 6.
Battery commander gives target, &c., and orders: “Right section ranging section; remainder corrector 150 increase 10, 4400-4700,” for the long bracket.
No. 1 gun fires, elevation 4400 yds., P.S., round observed −No. 2 gun fires, elevation 4700 yds., P.S., round observed +
B.C.orders “4500-4600.”
No. 1 gun fires, elevation 4500 yds., P.S., round observed −No. 2 gun fires, elevation 4600 yds., P.S., round observed +
The 100 yds. bracket appears to be 4500-4600.B.C.orders: “Remainder 4500 time shrapnel,” and gives the ranging section 4500-4600 to “verify.” Guns 3, 4, 5, 6 set fuzes for 4500 with correctors 150, 160, 170, 180.
No. 1 gun fires, elevation 4500 yds., P.S., round observed −No. 2 gun fires, elevation 4600 yds., P.S., round observed +
B.C.orders: “Remainder 4500, one round gun fire, 3 seconds.”
No. 3 elevation 4500 yds. T.S. corrector 150 airNo. 4 elevation 4500 yds. T.S. corrector 160 airNo. 5 elevation 4500 yds. T.S. corrector 160 grazeNo. 6 elevation 4500 yds. T.S. corrector 180 graze
No. 3 elevation 4500 yds. T.S. corrector 150 air
No. 4 elevation 4500 yds. T.S. corrector 160 air
No. 5 elevation 4500 yds. T.S. corrector 160 graze
No. 6 elevation 4500 yds. T.S. corrector 180 graze
B.C.selects corrector 160 and goes to “section fire.”
The battery now begins to fire “for effect.”
No. 1 elevation 4500 yds. T.S. corrector 160 airNo. 3 elevation 4500 yds. T.S. corrector 160 air
followed by Nos. 5, 2, 4 and 6.
There is another method of ranging, viz. with time shrapnel only. In this the principle is that several shells, fired with the same corrector setting, but at different elevations, will burst in air at different points along one line. Bursts high in the air cannot be judged, and it is therefore necessary to bring down the line of bursts to the target, so that the bursts in air appear directly in front or directly in rear of it. Rounds are therefore fired (in pairs owing to possible imperfections in the fuzes) to ascertain the corrector which gives the best line of observation. This found, the target is bracketed by bursts low in the air observed + and −, as in the ordinary method with percussion shrapnel.
The operations of finding the “line of fire” and the proper elevation may be combined, as the shells in ranging can be made to “bracket” for direction as well as for elevation. The line can be changed towards a new target in any kind of direct and indirect laying, in the latter case by observing the angle made with it by the original line of fire and giving deflection to the guns accordingly. Further, the fire of several dispersed batteries may be concentrated, distributed, or “switched” from one target to another on a wide front, at the will of the commander.
31.Observation of Fire, on the accuracy of which depends the success of ranging, may be done either by the battery commander himself or by a special “observing” party. In either case the shooting is carefully observed throughout, and corrections ordered at any time, whether during the process of ranging or during fire for effect. The difficulties of observation vary considerably with the ground, &c., for instance, the light may be so bad that the target can hardly be seen, or again, if there be a hollow in front of the target, a shell may burst in it so far below that the smoke appears thin, the round being then judged “over” instead of “short.” On the other hand, a hollow behind the target may cause a round to be lost altogether. Ranging with time shrapnel has the merit of avoiding most of these “traps.” The “French system of fire discipline,” referred to below, has this method as the usual procedure.
32.Fire.—Field Artillery ranges are classed in the British service as: “distant,” 6000 to 4500 yds.; “long,” 4500 to 3500; “effective,” 3500 to 2000: and “decisive,” 2000 andunder. The actual methods of fire employed are matters of detail; it will be sufficient to say that “section fire,” in which the two guns of a section are fired alternately at a named interval, usually 30 seconds, and “rapid fire,” in which two, three or more rounds as ordered are fired by each gun as quickly as possible, are the normal methods. Each battery usually engages a portion of the objective equal in length to its own front, owing to the spread of the cone of shrapnel bullets (see below). The fire is, of course, almost always frontal, though enfilade and oblique fire, when opportunities occur for their employment, are more deadly than ever, because of the depth of the cone. As for the general conduct of an artillery action, accurate fire for effect, at a medium rate, is used in most armies, but in the French and, since 1906, in the British services a new method has arisen, in consequence of the introduction of the modern quick-firer and the perfection of the time shrapnel. The French battery (1900 Q.F. equipment) consists of four guns and twelve wagons. The gun is shielded, as also are the wagons; the high velocity and flat trajectory give a maximum depth to the cone of shrapnel bullets. In the hope of obtaining a rapid and overwhelming fire, the French artillery ranges only for a long bracket, and once this bracket is found, the ground within its limits is swept from end to end in a burst of rapid fire. This is termed arafale(squall or gust), and technically signifies “a series of eight rounds per gun, each two rounds being laid with 100 metres more elevation than the last pair, the whole fired off as rapidly as possible.” The cone of time shrapnel being assumed as 300 yds. (or metres), it is clear that four pairs of rounds, bursting, say, at 1000, 1100, 1200 and 1300 yds. (adding, for the last, 300 yds. for its forward effect), sweep the whole ground between 1000 and 1600 yds. from the guns. The maximum depth would, of course, be obtained with four elevations differing by the depth of the cone; in such a case the space from 1000 to 2200 yds. would be covered, though much less effectively, since the same number of bullets are distributed over a larger area. On the other hand, therafale, at a minimum, covers 300 yds., all the guns in this case being laid at the same elevation throughout. Here the maximum number of bullets is obtained for every square yard attacked. Between these extremes, a skilful artillery officer can vary therafaleto the needs of each several case almost indefinitely. “Sweeping” fire is a series of three rounds per gun, one in the original line, one to the right and one to the left of it; this is significantly called “mowing” (tir fauchant). A further refinement in both services is the combined “search and sweep.” Forty-eight rounds, constituting in the French army a series of this last kind, can, it is said, be fired in 1 minute and 15 seconds, without setting fuzes beforehand, to cover an area of 600 × 200 metres. The result of such a series, worked out mathematically, is that 19% of all men and 75% of all horses, in the area and not under cover, should be hit by separate bullets (Bethell,Modern Guns and Gunnery, 1907). Even allowing a liberal deduction for imperfect distribution of bullets, we may feel certain that nothing but shielded guns could live long in the fire-swept zone. This is, of course, a rate of fire which could not be kept up for any length of time by the same battery. A French battery, firing at the maximum rate, would expend every available round in 13 minutes.
33.Projectiles Employed.—“Time shrapnel,” say the German Field Artillery regulations, “is the projectilepar excellence... against all animate targets which are not under cover.” It achieves its purpose, as has been said, by sending a shower of bullets over an area of ground in such quantity that this is swept from end to end. These bullets are propelled, in a cone, forward from the point of burst of the shell, and the effective depth of this cone at medium ranges with a fairly high velocity gun may be taken at 300 yds. Further, the corrector enables the artillery commander to burst his shells at any desired point; for example, a long fuze may be given, to burst them close up when firing upon a deep target (such as troops in several lines, one behind the other), and thereby to obtain the maximum searching effect, or to obtain direct hits on shielded guns, while a short corrector, bursting the shell well in front of the enemy, allows the maximum lateral spread of the bullets, and therefore sweeps the greatest front. The number of bullets in the shell is such that troops in the open under effective shrapnel fire must suffer very heavily, and may be almost annihilated. If the enemy is close behind good cover, the bullets, indeed, pass harmlessly overhead. This, however, leads to a very important fact, viz. that artillery can keep down the fire of hostile infantry, “blind” the enemy, in Langlois’ phrase, bypinning it downto cover. Under cover the men are safe, but if they raise their heads to take careful aim, they will almost certainly be hit. Their fire under such conditions is therefore unaimed and wild at the best, and may be wholly ineffective.Commonshell andhigh-explosiveshell (seeAmmunition) belong to another class of projectile. The former is now not often used, but a certain proportion of H.E. shell is carried by the field artillery in many armies (see table inOrdnance:Field Equipments). This has a very violent local effect within a radius of 20 to 25 yds. of the point of burst (seeAmmunition, fig. 10). It therefore covers far less ground than shrapnel, and is naturally used either (a) against troops under substantial cover or (b) to wreck cover and buildings. In the former case the shell is supposed to send a rain of splinters vertically downwards. This it will do, provided the fuze is minutely accurate, and a burst is thus obtained exactly over the heads of the enemy, but this is now generally held to be unlikely, and in so far as effect againstpersonnelis concerned the H.E. shell is not thought to be of much value. Indeed, in the British and several other services, no H.E. shells at all are carried by field batteries, reliance being placed upon percussion shrapnel in attacking localities, buildings, &c., and for ranging. Experiments have been made towards producing a “H.E. shrapnel,” which combines the characteristics of both types (see, for a description,Ammunition). For the projectiles used in attacking shielded guns, see section on “field howitzers” below.Case shotis now rarely employed. In the war of 1870-71 Prince Kraft von Hohenlohe-Ingelfingen, who commanded the Prussian Guard artillery, reported the expenditure of only one round of case, and even that was merely “broken in transport.” The close-quarters projectile of to-day is more usually shrapnel with the fuze set at zero. Langlois, however, calls case shot “the true projectile for critical moments, which nothing can replace.”
34.Tactics of Field Artillery.—On the march, the position and movement of the guns are regulated by the necessity of coming quickly into action; the usual place for the arm is at or near the heads of the combatant columns,i.e.as far forward as is consistent with safety. Safety is further provided for by an “escort,” or, if such be not detailed, by the nearest infantry or cavalry. In attack, the role of the field artillery is usually (1) to assist if necessary the advanced guard in the preliminary fighting—for this purpose a battery is usually assigned to that corps of troops, other batteries also being sent up to the front as required, (2) to prepare, and (3) to support or cover the infantry attack. “Preparation” consists chiefly in engaging and subduing the hostile artillery. This is often spoken of as the “artillery duel,” and is not a meaningless bombardment, but an essential preliminary to the advance. Massed guns with modern shrapnel would, if allowed to play freely upon the attack, infallibly stop, and probably annihilate, the troops making it. The task of the guns, then, is to destroy the opposing guns and artillerymen, a task which will engage almost all the resources of the assailant’s artillery in the struggle for artillery superiority. Shielded guns, enhanced rate of fire, perfection in indirect laying apparatus, and many other factors, have modified the lessons of 1870, and complicated the work of achieving victory in the artillery duel so far that the simple “hard pounding” of former days has given way to a variety of expedients for inflicting the desired loss and damage, as to which opinions differ in and within every army. One point is, however, clear and meets with universal acceptance. “The whole object of the duel is to enable the artillery subsequently to devote all available resources to its principal task, which is the material and moral support of the infantry during each succeeding stage of the fight” (French regulations). One side must be victorious in the end, and when, and not until, the hostile artillery is beaten out of action, thevictor has acquired the power of pressing home the attack. The British regulations (1906), indeed, deal with the steps to be taken when, though the artillery of the attack is beaten, the infantry advance is continued, but only so as to order the guns to “reopen at all costs,” in other words, as a forlorn hope. The second part of the preparation, the gradual disintegration of the opposing line of infantry, has practically disappeared from the drill books. The next task of the guns, and that in which modern artillery asserts its power to the utmost, is thesupportof the infantry attack. The artillery and infantry co-operate, “the former by firing rapidly when they see their own infantry ... press forward, and the latter by making full use of the periods of intense artillery fire to gain ground” (BritishF.A. Training, 1906). Thus aided, the infantry closes in to decisive ranges, and as it gains ground to the front, every gun “must be at once turned upon the points selected ... the most effective support afforded to the attacking infantry by the concentrated fire of guns and field howitzers. The former tie the defenders to their entrenchments (for retreat is practically impossible over ground swept by shrapnel bullets), distract their attention and tend to make them keep their heads down, while the shell from the field howitzers searches out the interior of the trenches, the reverse slopes of the position, and checks the movement of reinforcements towards the threatened point.” In these words the British Field Artillery drill-book of 1902 summarizes the act of “covering” the infantry advance. Unofficial publications are still more emphatic. The advance of the infantry to decisive range would often be covered by a mass of one hundred or more field guns, firing shrapnel at the rate of ten rounds per gun per minute at the critical moment. Against such a storm of fire the defending infantry, even supposing that its own guns had refitted and were again in action, would be powerless. It is in recognition of the appalling power of field artillery (which has increased in a ratio out of all proportion to the improvements of modern rifles) that the French system has been elaborated to the perfection which it has now attained.
With modern guns and modern tactics artillery almost invariably fires over the heads of its own infantry. The German regulations indeed say that it should be avoided as far as possible, but, as a matter of fact, if the numerous guns of a modern army (at Königgrätz there were 1550 guns on the field, at Gravelotte 1252, at Mukden 3000) were to be given a clear front, there would be no room for deploying the infantry. Consequently the French regulations, in which the power of the artillery is given the greatest possible scope, say that “it almost always fires over the heads of its own infantry.” With field guns and on level ground it is considered dangerous that infantry in front of the guns should be less than 600 yds. distant—not for fear of the shells striking the infantry, but because the fragments resulting from a “premature” burst are dangerous up to that distance. The question of distance is more important in connexion with the “covering” of the assault. Up to a point, the artillery enables the attacking infantry to advance with a minimum of loss and exhaustion, and thus to close with the enemy at least on equal terms, if not with a serious advantage, for the fire of the guns may shake, perhaps almost destroy the enemy’s power of resistance. But when the infantry approaches the enemy the guns can no longer fire upon the latter’s front line without risk of injuring their friends. All that they can do, when the opposing infantries can see the whites of each other’s eyes, is to lengthen the fuze, raise the trajectory and sweep the ground where the enemy’s supports are posted. Under these circumstances it is practically agreed that the risk should be taken without hesitation at so critical a moment as that of a decisive infantry assault which must be pushed home at whatever cost. “It will be better for the infantry to chance a few friendly shells than to be received at short range with a fresh outburst of hostile rifle fire” (Rouquerol,Tactical Employment of Quick-firing Field Artillery). Thus, the distance at which direct support ceases, formerly 600 yds., has been diminished to 100, and even to 50 yds. Howitzers can, of course, maintain their fire almost up to the very last stage, and, in general, high-explosive shell, owing to its purely local effect, may be employed for some time after it has become unsafe to use shrapnel.
35. Field artillery indefence, which would presumably be inferior to that of the attack, must, of course, act according to circumstances. We are here concerned not with the absolute strength or weakness of the passive defensive, which is a matter of tactics (q.v.), but with the tactical procedure of artillery, which, relatively to other methods, is held to offer the best chance of success, so far as success is attainable. On the defensive in a prepared position, which in European warfare at any rate will be an unusually favourable case for the defender—the guns have two functions, that of engaging and holding the hostile artillery, and that of meeting the infantry assault. The dilemma is this, that on the one hand a position in rear of the line of battle, with modern improvements in communicating and indirect laying apparatus, is well suited for engaging the hostile guns, but not for meeting the assault; and on the other, guns on the forward slope of the defender’s ridge or hill can fire direct, but are quickly located and overwhelmed, for they can hardly remain silent while their own infantry bears the fire of the assailant’s shrapnel. Thus the defender’s guns would, as a rule, have to be divided. One portion would seek to fight from rearward concealed positions, and use every device to delay the victory of the enemy’s guns and the development of the battle until it is too late in the day for a serious infantry attack. Further, the enemy’s mistakes and the “fortune of war” may give opportunities of inflicting severe losses; such opportunities have always occurred and will do so again. In the possible (though very far from probable) case of the defender not merely baffling, but crushing his opponent in the artillery duel, he may, if he so desires, himself assume the role of assailant, and at any rate he places a veto on the enemy’s attack.
The portion told off to meet the infantry assault would be entrenched on the forward slope and would take no part in the artillery duel. Very exceptionally, this advanced artillery might fire upon favourable targets, but its paramount duty is to remain intact for the decisive moment. Here again the defender is confronted with grave difficulties. It is true that his advanced batteries may be of the greatest possible assistance at the crisis of the infantry assault, yet even so the covering fire of the hostile guns, as soon as the hostile infantry had found them their target, may be absolutely overwhelming; moreover, once the fight has begun, the guns cannot be withdrawn, nor can their positions easily be modified to meet unexpected developments. The proportion of the whole artillery force which should be committed to the forward position is disputed. Colonel Bethell (Journal Royal Artillery, vol. xxxiii. p. 67) holds that all the mountain guns, and two-thirds of the field guns, should be in the forward, all the howitzers and heavy guns and one-third of the field guns in the retired position. But in view of the facts that if once the advanced guns are submerged in the tide of the enemy’s assault, they will be irrecoverable, and that a modern Q.F. gun, with plenty of ammunition at hand, may use “rapid fire” freely, artillery opinion, as a whole, is in favour of having fewer guns and an abnormal ammunition supply in the forward entrenchments, and the bulk of the artillery (with the ammunition columns at hand) in rear. But the purely passive defensive is usually but a preliminary to an active counter-stroke. This counter-attack would naturally be supported to the utmost by the offensive tactics of the artillery, which might thus at the end of a battle achieve far greater results than it could have done at the beginning of the day. Inpursuit, it is universally agreed that the action of the artillery may be bold to the verge of rashness. The employment of field artillery inadvancedandrear guard actionsvaries almost indefinitely according to circumstances; withoutposts, guns would only be employed exceptionally.
36.Marches.—The importance of having the artillery well up at the front of a marching column is perhaps best expressed in the phrase of Prince Kraft von Hohenlohe-Ingelfingen, “save hours and not minutes.” The Germans in 1870 so far acted up to the principle that Prince Hohenlohe, when asked, at the beginningof the battle of Sedan, for a couple of guns, was able to reply, “You shall have ninety” (see, for details of the march of the Guard artillery, hisLetters on Artillery, 6th letter). The German regulations for field service say, very plainly, “the horses have not done their work until they have got the guns into action, even at the cost of utter exhaustion.” A notable march was made by the 62nd battery, R.F.A., in the South African War. On the day of the battle of Modder River, the battery marched 32 m. (mostly through deep sand) arriving in time to take part in the action. Such forced marches, if rare, are nowadays expected to be within the power of field artillery to accomplish. Horse artillery is capable of more than this, and as to pace, manoeuvring at the cavalry rate. Heavy guns are the least mobile, and would rarely be able to keep pace with infantry in a forced march. Field artillery walks 4, trots 9, and gallops at the rate of 15 m. an hour. A fair marching pace (trot and walk) is 4 m. an hour for field, 5 for horse batteries. A march of 14 m. would, according to the German regulations, be performed by
a field battery in 5 hours,a horse battery in 4 hours,
a field battery in 5 hours,
a horse battery in 4 hours,
under favourable circumstances (Bronsart von Schellendorf).
37.Power and Mobility.—It will have been made clear that every gun represents a compromise between these two requirements, and that each type of artillery has been evolved in accordance with the relative requirements of these conditions in respect of the work to be performed. The classification which has been followed in this article represents the practically unanimous decision of every important military state. Still, there has always been controversy between the individual adherents of each side, and the Boer War experiences raised the question as to whether field artillery, as the term is usually understood, should not be abolished, with a view to having only heavy guns and horse artillery with a field army.
38.Concentration and Dispersion.—The use of their artillery made by the Boers in the South African War led to the revival of the idea of “dispersing” guns instead of “concentrating” them. It would be more accurate to say that military thinkers had, after the introduction of the quick-firing gun, challenged every received principle, and amongst others the employment of artillery in masses, which, as a result of the war of 1870, “had become almost an article of faith.” The idea was to make use of the increased power of the guns to gain equally great results with the employment of less material than formerly. Thus the dispersion of guns is bound up with the passive defensive. The first editions of the BritishField Artillery TrainingandCombined Training, strongly influenced as they were by South African experience, did not legislate, even in dealing with defence, for “dispersion” in the Boer manner, but only for adaptability (seeField Artillery Training, 1902, p. 15). In the Boer War, whilst the Boers nearly always scattered their guns, almost the only occasion upon which their artillery played a decisive part was at Spion Kop, where its fire was concentrated upon the point of assault. At Pieter’s Hill, the fire of seventy guns covered the British infantry assault in the Napoleonic manner. On the whole it may be accepted as a general truth that guns are safe, and may be locally effective, when dispersed, but that they cannot produce decisive effect except when used in masses. It must, however, be clearly understood that a “mass” in this sense means a large number of guns, under one command, and susceptible of being handled as a unit, so far as the direction and effectiveness of their fire is concerned.This being secured, and on that condition only, it does not matter whether the actual gun positions are scattered over a few square miles, or are closed in one long line and using direct fire—they are still a mass, and capable of acting effectively as such. While there are undoubtedly grave dangers in using the indirect method too freely, technical improvements in laying, telephones, &c., have had much to do with the possibility, at any rate under favourable circumstances, of a concentration which may be described as one of shells rather than of guns, and the reader is reminded in this connexion that the work formerly done by the gun is now performed by the shell.
39.Horse Artilleryis to be regarded as field artillery of great mobility and manoeuvring power. Its value may be said, in general terms, to lie in augmenting the weak fire-power of the mounted troops, and in facilitating their work as much as possible. Thus, when cavalry meets serious opposition in reconnoitring, the guns may be able to break down the enemy’s resistance without calling for assistance from the main body of the cavalry, and, in the action of cavalryversuscavalry, the “paramount duty of the horse artillery is to shatter the enemy’s cavalry” (Field Artillery Training, 1906),i.e.to “prepare” the success of the cavalry charge by breaking up as far as possible the enemy’s power of meeting it. In the cavalry battle, covering fire is practically impossible, owing both to the short distances separating the combatants and to the rapidity of their movements, but steps are taken “to enable all the guns to bear on the enemy’s cavalry at the points of collision.” The ideal position for the horse artillery is out to a flank, the cavalry manoeuvring so as to draw the enemy’s cavalry under enfilade fire, and at the same time to force them to mask the fire of their own horse artillery. Another and a most important function of the horse batteries is to reinforce, with the greatest possible speed, any point in the general line of battle which is in need of artillery support. For this reason the corps artillery generally includes horse batteries.
40.Field Howitzersare somewhat less mobile than field guns; they have, however, far greater shell power. The special features of the weapon are, of course, the product of the special requirements which have called it into existence. These are, briefly (a) the necessity of being able to “search” the interior of earthworks, a task which, as has been said, is beyond the power of high-velocity field guns, and (b) demolition work, which is equally beyond the power of even a H.E. shell of field-gun calibre. The first of these conditions implies a steep “angle of descent,” which again implies a high angle of elevation. The second requires great shell power but does not call for high velocity. The howitzer, therefore, is a short gun, firing a heavy shell at high angles of elevation. Howitzers almost always are laid by the indirect method of fire from under cover, since it is clear that, with high angles of elevation, the gun may be brought close up to the covering mass, and still fire over it. Ranging must be done very accurately and yet economically, as but few of their heavy shells can be carried in the wagons and limbers, and the shells descending upon an enemy almost vertically lose the long sweeping effect of the field shrapnel which neutralizes minor errors of ranging. The projectiles employed are high explosive and shrapnel, the latter for use againstpersonnelunder cover, the former for demolition of field works, casemates or buildings. It is very generally held that howitzer time shrapnel is the best form of projectile for the attack of shielded guns. Here it may be said that no completely satisfactory method of dealing with these has yet been discovered. The best procedure with field guns is said to be lengthening the fuze to obtain a high percentage of bursts on graze. A shell striking the face of the shield will penetrate it, and should kill some at least of the gun detachment behind. The high-explosive shrapnel alluded to above is designed primarily for the attack of shielded guns.
41.Heavy Field Artillery, alternatively calledArtillery of Position, as has been said, includes all guns of 4-in. calibre and upwards, mounted on travelling carriages. In South Africa, where firm soil was usually to be found, 6-in. guns were employed as heavy field guns, but in Europe even the 5-in. (British Service) is liable to sink into the ground. In Great Britain, guns only are used by this branch; abroad, the “heavy artillery of the field army,” the “light siege train,” &c., as it is variously called, is as a rule composed of howitzers of a heavier calibre than the field howitzer, the 15-cm. (6-in.) howitzer being most commonly met with. This artillery has, however, a different tactical rôle from the heavy field artillery of the British service; and it is always with a view to the attack of permanent or semi-permanent fortifications that thematérielis organized. In Great Britain, heavy batteries armed with the 5-in. gun are considered as “an auxiliary to the horse and field artillery” (Heavy Artillery Training). Ranging is conducted with greaterdeliberation than ranging with the lighter guns, though upon the same general lines. Parts of the process may, however, be omitted in certain circumstances. Heavy guns use high-explosive (lyddite) shells and time shrapnel, the former for ranging and for demolishing cover, the latter againstpersonnel. Laying is usually indirect. The tactical principles upon which heavy artillery does its work are based, in the main, on the long range (up to 10,000 yds.) and great shell-power of the guns. This power enables the artillery to reach with effect targets which are beyond the range of lighter ordnance, and it is, therefore, considered possible to disperse the guns in batteries, and even in sections of two guns, along the front of the army, without forfeiting the power of concentrating their fire on any point—a power which otherwise they would not possess owing to their want of mobility. At the same time it is not forbidden to bring them into line with the rest of the artillery, in order to achieve a decisive result. In theattack, beside the general task of supplementing the effect of other natures of ordnance, heavy artillery may demolish cover, buildings, &c., held by the enemy, and during the infantry assault they may do excellent service in sweeping a great depth of ground, their smaller angle of descent, and the greater remaining velocity and heavier driving charge of their shrapnel, as compared with field guns, enabling them to do this effectively. In thedefence, long-range fire has great value, especially in sweeping approaches which the enemy must use. Inpursuit, the heavy artillery may be able to shell the main body of the enemy during its retreat, even if it has left a rearguard. Inretreat, the want of mobility of these guns militates against their employment in exposed positions, such as rearguards usually have to take up.