the chief function of land artillery in its earlier days was the destruction of material. the huge engines of the ancients were of value in effecting from a safe distance what the tortoise and the battering-ram could only do at close quarters: the breaching of walls and the battering-in of gates, doors and bulwarks. after the invention of gunpowder the use of artillery remained, we have seen, substantially the same. apart from the moral effect on horse and man of the “monstrous roare of noise” when in defence, the offensive object of ordnance was almost entirely the breaching of the enemy’s works. the guns were literally “pieces of battery,” doing their slow work by the momentum of their large projectiles.
thus considered, artillery was not a very effective instrument. and, just as in earlier times it had been sought to supplement mere impact by other effects—by the throwing into besieged fortresses of quicklime, for instance, “dead horses and other carrion,”—so, after the arrival of gunpowder, endeavour was made to substitute incendiarism or explosion for the relatively ineffective method of impact. the use of grenades, hand-thrown, was discovered. and then followed, as a matter of course, their adaptation to the mortars already in use for the projection of stones and other solid material. these mortars, as in the case of the early cannon, were at first made of an inconveniently large size; and, also as in the case of cannon, they came later to be cast of more moderate proportions to facilitate their transport and thus render them more serviceable for operations in the field. artillery was now devoting its attention to the personnel. the result of this evolution was the howitzer, a weapon whose value to land armies was greatly enhanced by the discovery, by marshal vauban at the end of the seventeenth century, of the efficacy of the ricochet. under this system the fuzed bomb or grenade,161 instead of being projected from a mortar set at a high elevation, to describe a lofty and almost parabolic trajectory, was discharged from a howitzer at a sufficiently low elevation to cause it to strike the ground some distance short of its objective, whence it proceeded, leaping and finally rolling along the ground till it came to its target, where it exploded.
so far shell fire had developed on land. in sea warfare the solid cannon ball remained the orthodox missile; the use of explosive or incendiary shells was deemed so dangerous a practice as to forbid its acceptance by the great maritime powers, save in exceptional cases, until the nineteenth century. toward the end of the eighteenth century serious consideration was given, by france especially, to the possibilities of shell fire. frenchmen felt restless and dissatisfied with the conditions in which they were waging war with england. sea ordnance, which in the past had wrought so much by the destruction of personnel, was becoming increasingly impotent, not only against personnel but against ships themselves. trafalgar came as a proof of this, when not a single ship was sunk by gunfire. sea fighting was again resolving itself into a straightforward physical struggle between the guns’ crews of the opposing fleets, in which struggle the victory went by attrition to the side which plied its guns with the greatest rapidity and perseverance. élan, enthusiasm, science, the mental alertness of the individual, were bound to be overborne in such a case by superior endurance, physique, coolness, and sound workmanship. both sides had a profound belief in the162 superiority of their personnel in hand-to-hand conflict. where fighting was, as in the earliest days of the rival navies, “man to man, lance to lance, arrow to arrow, stone to stone,” success depended entirely upon courage and physical strength; and in such cases, says nicolas, the english were almost always victorious. if, stated a french writer, sea actions could be decided by hand-to-hand combat the arms of france would triumph. but sea fights were in fact almost solely a matter of artillery. if only the conditions of battle could be altered; if only the forces of incendiarism or explosion could be summoned to put the enemy ships-of-the-line in jeopardy, a short cut to victory might be found or, at any rate, the superiority of england in material might be seriously depreciated.
some time was to elapse, however, before france was to see even the partial consummation of this fervent desire.
while the use of grenades, bombs, carcasses and other explosive and incendiary missiles had been recognized on land for centuries, an event occurred in the year 1788 which, coming to the ears of europe, should have had considerable effect in turning the thoughts of artillerists to the possibilities of their use at sea. in that year, some sixty-five years before the action off sinope, a deptford shipwright who had risen to high service under the russian government fitted out for his employers a flotilla of long-boats for an attack upon a turkish squadron. these long-boats sir samuel bentham—he was the ex-shipwright—armed with brass ordnance mounted on his163 favourite non-recoil system, and for them he requisitioned a large supply of shells, carcasses and solid shot. at the mouth of the liman river in the sea of azov the russians, with these insignificant war vessels, attacked a very superior force of turkish ships, and gained a complete victory. the effect of the shells, fired at close range into the turkish ships, was startling and impressive. great holes were torn in the sides of the vessels, and fires were started which, in a favouring medium of dry timber and paint and pitch, rapidly spread and caused the squadron’s destruction.
no evidence can be quoted, it must be admitted, to show that contemporary opinion realized how portentous was this sea action; no stress is laid on the event in histories relating to that time. nor does another event which occurred at this period appear to have caused the notice it deserved: the firing, at the suggestion of a captain mercier, 35th regiment, of mortar shells from the british long 24-pounders, from gibraltar into the spanish lines.100 nor was lieutenant shrapnel’s contemporaneous invention,101 of a shell containing case shot explodable by a small bursting charge, developed or the possible adaptation of its use for sea warfare fully appreciated. or, if authority did discern the eventual effect of these innovations, a wholesome dread of their extension and development in naval warfare appears to have dictated a policy of calculated conservatism in respect of them, a suppression of all ideas and experiments which had in view any intensifying or improvement of our artillery methods. “so long as foreign powers did not innovate by improving their guns, by extending the use of carronades and, above all, by projecting shells horizontally from shipping; so long it was our interest not to set the example of any improvement in naval ordnance—the value of our immense material might otherwise be depreciated. many of the defects which were known to exist, so long as164 they were common to all navies, operated to the advantage of great britain.”102
apart from this consideration, however, it is remarkable how small a value was set by english opinion, even at a late date, upon explosive as compared with solid projectiles. the obvious disadvantages of hollow spherical shell—their smaller range, more devious flight and less penetrative power—were emphasized; their admittedly greater destructive effect (even taking into account the small bursting charges deemed suitable for use with them) was rated at a surprisingly low figure.
the french, on the other hand, showed great eagerness to explore the possibilities of shell fire in fighting ships. addicted to science, they searched unceasingly throughout the revolutionary wars for some development of naval material which would neutralize the obvious and ever-increasing superiority of the british navy under existing conditions, even if it might not actually incline the balance of power in their favour. to this end they courted the use of incendiary projectiles. our own authorities, partly from a lively apprehension of the danger believed to be inherent in their carriage and use in wooden ships and partly from a feeling of moral revulsion against the employment of what they genuinely believed to be an unfair and unchivalrous agency, limited the use of fuzed shells, carcasses and other fireworks as much as possible to small bomb vessels of special construction—and inferior morals. but in ships-of-the-line the use of such missiles was strongly deprecated by naval opinion, and even the use of hand-grenades in the tops was forbidden by some captains. time justified this cautious attitude. the french suffered for the precipitancy with which they adopted inflammatory agents; fires and explosions were frequent in their fleets; the history of their navy in these wars—“la longue et funeste guerre de la révolution”—is lit up from time to time with the conflagrations of their finest ships, prey to the improperly controlled chemical forces of their own adoption. one example alone need be cited: the orient at the battle of the nile. even if the french flagship was not set on fire by their direct agency, small doubt exists that the spread of the fire which broke out in her was accelerated by the presence of the combustibles which, in common with most of the french ships, she carried. throughout the wars fuzed shells, carcasses, stinkpots, port-fires,165 proved far more terrible to friend than foe. and the foe doubtless felt confirmed and fortified in his opinions that such substances were quite unsuitable for carriage in warships. as to the ethics of explosives even the french themselves seem to have been doubtful. for, shortly after the battle in aboukir bay, some of their officers accused an english captain of having been so “unfair” as to use shells: an audacious man?uvre on their part, for, on some of the shells in question being produced and the gunner questioned as to whence they came, “to the confusion of the accusers, he related that they were found on board the spartiate, one of the ships captured on the first of august!”103
continuous trials were carried out in france with shells fired from guns. in 1798, following a series of successful experiments, trials were prosecuted at meudon by a special commission, who caused 24-and 36-pound shells to be fired at a target representing a ship-of-the-line, at ranges of 400 and 600 yards. the results were impressive, and the report rendered to bonaparte such as to confirm his personal conviction in the value of shell fire. less than a year later, we may note in passing, the consul was himself the target of shell fire: being subjected, at the siege of acre, to the unpleasant attentions of a 68-pounder carronade from the english fleet. in 1804, with the avowed object of keeping our cruisers at a distance, he had long howitzers cast and placed for the defence of toulon and other ports. and hardly a year passed but some trial was made of horizontal fire of shells from guns and mortars.
of the two great maritime powers, britain had contributed more, perhaps, towards the building up by actual practice of the system of artillery which was shortly to come into vogue. shell fire from mortars had been used with far more effect by her forces than by those of her great enemy. the invention of the carronade was in itself almost a solution; and, though it did not lead directly to the shell gun, yet it undoubtedly induced the weapon which most strongly resembled it: the medium ship-gun, as designed by congreve and blomefield, which was something between the carronade and the long gun, and which for a time was mounted in our two-decked ships for the purpose of preserving unity of calibre.
but the french, free from the bias against change of method166 and material which operated in this country, seized on the possibilities of existing elements, and combined them in such a way as to form a complete solution of the shell-fire problem. to general paixhans, the eminent officer of artillery, the credit for this solution is undoubtedly due.
§
the experiments of m. paixhans, carried out in order to confirm the theories on which his new system was founded, extended over several years and resulted in the publication of two books—the nouvelle force maritime et artillerie, 1822, and expériences faites sur une arme nouvelle, 1825.
in these works104 the author developed in detail the scheme of ship armament which was to win adoption, in the course of time, in the french navy; whereby our own authorities were also gradually forced to abandon methods and standards of force by which the british navy had grown great. two principles formed the basis of this scheme:—(1) unity of calibre, embodying the maximum simplification of means; (2) shell fire, embodying the maximum augmentation of effect.
on these two principles m. paixhans reared and elaborated in minutest detail the revolutionary system with which his name is associated. no new element or discovery was necessary for giving effect to his designs. indeed he expressly disclaimed having introduced any novelty: “nous n’avons donc rien inventé, rien innové, et presque rien changé; nous avons seulement réuni des élémens épars, auxquels il suffisait de donner, avec un peu d’attention, la grandeur et les proportions convenables, pour atteindre le but important que nous étions proposé.” it may be said, in fact, that unity of calibre had been an ideal sought for years before m. paixhans’ time; while shell fire, the new arm of 1822, was almost the logical consequence of robins’ discoveries in the principles of gunnery, extended as they were by the researches of doctors hutton and gregory. in particular, mention is made by m. paixhans himself of two of the results brought out by dr. hutton’s experiments: one, that the length of the bore of a gun has but a small effect upon the range of its projectile, the range varying167 as the fifth root of the length; two, that the muzzle velocity may be considered to be independent of the weight of the gun.
as to the lack of novelty of shell fire on ship-board, m. paixhans gives a significant extract from french naval annals. in 1690, it appears, a m. deschiens had invented a means of firing bombs from long guns horizontally, instead of parabolically as from mortars. this secret was of great use to him; for, falling in with four english ships at sea, he so surprised them by this new invention that, fearful of being set on fire, they drew off and did not attempt to renew battle. this same french captain at a later date attacked two dutch ships more than a match for him, and, by means of these horizontally fired bombs, sank one and disabled the other. but m. deschiens died and his secret with him; though, as m. paixhans remarks, this “secret” would have been easy to find if anyone had looked for it.
a whole chapter of the genuine use and effects of the gunne, written by robert anderson and published at london in 1674, concerns “the shooting of granados out of long gunnes.”
briefly, the grand idea of m. paixhans consisted in the establishment of a fleet of steam vessels armed with guns designed to project charged shells horizontally at considerable velocities. but as this consummation could only be attained by degrees, he proposed that in the meantime the existing french fleet should be re-armed in such a way as to give to each ship a maximum of force combined with unity of calibre. this part of his scheme was applicable to solid shot (boulets massifs) as well as to shell (boulets creux). but the former he considered too ineffectual for use in future sea engagements. although they might be the most suitable projectiles for the destruction of land works, the breaching of ramparts and the battering of stone walls, yet hollow shot, filled with powder and other combustible material, were far better adapted to rend and set fire to defences of wood, impregnated with tar, and, in time of action, replete with every species of inflammable substance, and crowded with combatants. no, m. paixhans hoped to make solid shots entirely obsolete, by adopting, in combination with small steam vessels, or, for the present, in combination with the existing fleets of sailing ships, an ordnance specially dedicated to shell fire, and to shell fire alone. by its means the enormous superiority of great britain would be effectually eliminated, or transferred into the168 hands of france; her material would be rendered suddenly obsolete, her maritime power would shrivel; and the power of france would be augmented to such a degree that the defeat of these islands might at last be encompassed.
such was the amiable intention of m. paixhans.
the arguments which he employed in favour of his revolutionary proposals are of sufficient interest and importance, perhaps, to merit consideration. the past histories of the two navies showed, he argued, that the introduction of improvement or of innovation into either navy was shortly afterwards followed by its introduction into the other; so that there was never any important change in the relative naval strength of the two nations. it followed, therefore, that the only means by which power could be wrested from the possessor of it, must be such a change of system as would render useless the existing means by which that power was sustained. how could this be accomplished? foreign nations had always felt the innate strength of england, residing in the race of splendid seamen (a highly specialized profession) who formed so great a part of her population. france especially had felt her own weakness in not possessing a reserve, a nursery of seamen, such as england had. if only seamanship could be discounted——! m. paixhans proceeded to show that the coming of the steamer was itself an event which would go a long way to discount a superiority in seamanship. the accursed english “devil boat,”105 which had begun to spread its pall of smoke over all the northern waters, might be, in truth, a potent friend to france. steam vessels required only a small and unskilled personnel to man them, instead of prime seamen. steam vessels could always outstrip sailing ships, and thus could choose their own range and accept or decline battle as occasion required. moreover, the effect of shell fire would be to upset completely the balance of power existing between big ships and little ships, as such. instead of size being a measure of power, it would be a measure of vulnerability. the larger the ship the more she would be endangered. costly three-deckers would cease to exist, and in their place small steam vessels, fast and heavily armed, easily man?uvred and perhaps encased in armour, would hold power. thus the great obstacle to the acquirement by france of a large naval force—the necessity for a numerous and experienced personnel—would be easily169 removed. in short, the adoption of his scheme would in any case be most favourable to france. even if it were simultaneously adopted by great britain its adoption would at least ensure that in future the naval power of the two states would be in proportion to the strength of their whole population, instead of only that part of it familiarized with maritime affairs.
considering first the conversion of the existing french navy, he examined and enlarged upon the various inefficiencies inherent in the usual disposition of ship armaments; in the manner in which the unit and the number of units of artillery force were selected for any individual design of ship; in the variety of the units, and in the lack of system observed in the various proportions between the gun, the charge and the projectile. he observed that the constant tendency of development, both in the french and in the english navy, was in the replacing of smaller by greater calibres, by which process the diversity of calibres was diminished and the effective force of the armament increased. continuing this process, it appeared that the ideal armament would be reached, the maximum degree of force would be attained, when unity of calibre was achieved. when the calibre of the largest-sized cannon carried on the principal gun deck of ships-of-the-line was adopted as the sole calibre used, the maximum of force would be attained: the greatest possible destructive effect combined with the greatest possible simplification of means. these remarks applied equally to a solid shot and to a shell gun armament. if for some reason it were decided not to adopt shell fire, nevertheless it would be of advantage to re-arm the french sailing fleets on this principle, with guns of one calibre.
m. paixhans proposed as the unit the french 36-pounder. he explained the advantages to be derived from arming existing ships-of-the-line with 36-pounders all of the same calibre but of different weights on the respective decks. the guns on different decks would take different charges and would therefore project the shot with different muzzle velocities. they would be disposed, the heaviest on the lower deck; a lighter type (reamed out from 24-pounders) on the main deck; still lighter guns on the upper deck, and 36-pounder carronades on the quarter-deck and forecastle would complete the armament.
the employment of solid shot was not favoured by him, however, and he claimed the results of various trials as showing the170 superior offensive value of shells, when compared with solid shot. comparing a solid shot and a shell of the same external dimensions discharged with the same muzzle velocity, the former, he said, had only the advantage in superior range and penetrative power. the latter, while having a range greater than those at which sea actions were invariably fought and sufficient penetrative power to effect a lodgment in a ship’s timbers, required less powder to propel it, a lighter and therefore more rapidly worked gun from which to discharge it, and it had a destructive effect enormously greater than that of the solid ball.
the complete proposal therefore involved the adoption of shell guns exclusively, new guns being made and old guns being reamed out as necessary to enable each ship to carry pieces of one calibre alone. the calibre proposed as unit was the long french 48-pounder. and, as an example of the way in which m. paixhans would convert armaments, the case of the french 74-gun ship is here taken. this, with an existing armament of:—
28 36-pounders,
30 18-pounders,
14 6-pounders,
14 6-pounder carronades,
a total of 86 pieces throwing 2250 pounds of solid shot, he would convert into a ship armed with:—
28 48-pounders (reamed from 36-pounders),
30 48-pounders (of same weight as 18-pounders),
28 48-pounder carronades;
eighty-six pieces throwing 3010 pounds of charged shell weighing 35 pounds each.
for the new shell gun he proposed a design of iron howitzer in which the distribution of metal was so adjusted as to give a sufficient factor of safety at every section, while at the same time allowing the total weight of the piece to be reduced to a minimum. this canon-à-bombe was to be mounted on a stable form of carriage, made without trucks but fitted with running-out rollers and directing bars to control the line of fire and the direction of recoil.
to those who were inclined to regard with feelings of horror this new use of explosive missiles, this progress in the art of171 destruction, the inventor put the question, whether experience had not proved that the perfection of arms had not had the effect of making warfare actually less bloody; whether it was not a fact worth consideration, that, while in days of old the destruction and loss of life in battles was enormous, the loss of english seamen by gunfire in the numerous combats of three long and bitter wars of recent times amounted to less than five thousand killed. and would not, therefore, further development of arms be a positive benefit to humanity?106
one other feature was put forward to complete this scheme of re-armament, the importance of which it is unnecessary to emphasize. m. paixhans explored the possibility, by the sacrifice of a tier or more of guns, of rendering all classes of ships invulnerable by casing their sides with iron plates. although rejected at the time, and as the result of trials which he himself carried out, this suggestion was destined to be carried into effect in startling fashion some thirty years later: with what consequences to naval architecture we shall presently see. in connection with the scheme of re-armament outlined by m. paixhans in 1822 the suggestion was important in that there was implied in it an admission of one of the two weak features of the inventor’s system. the shell gun would lose its superiority over the shot gun, and might indeed be reduced to absolute impotence if, in imitation of france, the enemy also cased his ships of war with iron. the solid shot gun would once again have the advantage; in fact, that very equilibrium of relative values which m. paixhans was endeavouring to destroy would once more obtain between the navies of the two rival powers.
for this reason, presumably, and because the shell gun system contained, though in a less degree, the disability inherent in the carronade system—inferior ranging power, enabling a clever opponent armed with long solid shot guns to fight at a range which was too great for shell—the paixhans scheme was not adopted in its entirety by the french government of the time. but the principle of unity of calibre was172 acclaimed and approved almost immediately, applied to solid shot guns. the french 30-pounder was chosen as the unit. in 1829 guns of this calibre, made on several different models to suit the various decks and classes of ship, were mounted in their fleets.107
in the meantime m. paixhans had made further progress toward perfecting the details of his shell gun system. a canon-obusier of 80 pounds was made to his design, a chambered howitzer of the same weight (about 72 hundredweight) as the french 36-pounder truck gun and of 22 centimetres calibre. this was designed to project a hollow shell of the same size as the french 80-pound solid shot, but weighing, when its cavity was filled with a charge of 4 pounds of powder, 56 pounds french (62? pounds english). the shell gun itself was of a distinctive shape. the characteristics of short chase, large bore, a chamber, a small propelling charge, and a scientific elimination of all useless metal, resulted in a form of ordnance quite different from that of the long-accepted smooth-bore cannon. it was easily recognizable by its straight muzzle, smooth lines and the absence of the usual ornaments and reinforcing rings. when, eventually, the new arm was adopted by other powers, their shell guns too, though independently evolved, were found to exhibit the same external features: the features of what came to be known universally as a “paixhans gun.”
the terrific effect of charged shell, fired from this form of gun with sufficient velocity to find a lodgment in a ship’s timbers, was demonstrated at brest in 1821 and 1824; in the latter trials the target being a frigate, the pacificateur, moored in the roadstead. high range and accurate shooting were obtained. the incendiary effect of the shell was prodigious: so impressive, indeed, that in spite of a strong opinion in the french navy against further carriage of bombs in ships-of-the-line, the commission recommended “that canons-à-bombe be adopted, even in ships-of-the-line, but in small numbers.”
but though the principle of the shell gun was accepted by experts, public opinion was not yet ready for the change. the commission had shown a sage circumspection in regard to the173 extent of the change proposed; but public opinion was not yet satisfied that the new arm was sufficiently safe. the scheme suffered a long postponement. in the meantime several further trials were held. the design of the piece was again modified; a larger chamber was arranged and a support was cast, at the commencement of the chase, for carrying a sight. tests à outrance were made to find what maximum charge such a shell gun would safely stand; and at last, in 1837, the principle of shell fire was accepted by the government, the paixhans gun being assigned a place in the prescribed armament of the fleets of france. to the impairment of the unity-of-calibre principle, lately achieved, shell guns of 22 centimetres were admitted as part-armament of ships the greater number of whose pieces were 30-pounders firing solid shot.
a paixhans gun
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in england the arguments in favour of a new and more scientific adjustment of ship armament had not until this date been clearly formulated. of the tendency to a single calibre there certainly had been many demonstrations in the last decades of the eighteenth century: a tendency favoured by the replacement of the smaller long guns of the fleet by carronades. sir howard douglas, in his naval gunnery, the first edition of which was published in 1820, had demonstrated the advantages of large calibre, the inefficiency of random broadsides, and the high importance of the deliberate aim of single guns. and in 1825, before the french began to remodel their ordnance, colonel munro, of the royal artillery, submitted his project to the naval authorities of arming our ships solely with 32-pounders, of different classes and weights to suit the various circumstances. but no radical revision of armament was made in the british navy until some years after174 the french had made the great stride of 1829, already described.
unity of calibre, then, was no novel idea on the part of m. paixhans. “no project,” says dahlgren—“no project has proved more attractive to naval men than that of having a uniform calibre throughout the entire fleet. it has been proposed from time to time without success, until adopted for the french navy in 1829.
“in the promptness with which the example was followed by england and the united states, may be recognized the general convictions of the profession in regard to the serious mischief inseparable from the chaos of calibres that prevailed, and the urgent necessity for some measure that would simplify the complex economy of naval ordnance.
“in a three-decker might be witnessed the extreme phase of the evil: long 32-pounders, 18-pounders, and carronades, requiring three sizes of shot and four classes of full charge, with as many reduces as caprice might suggest. all this variety of supply was to be distinguished and selected in the magazines and shot-lockers—circulated with perfect exactness in the confusion and obscurity of the lower passages, to a particular hatchway, then up to the deck where was placed the gun for which each charge or shot was designed: and this was to be accomplished, not with the composure, deliberation, and attention that the nature of the operation itself demanded, but amid all the excitement and hot haste of battle.”108
the plans of m. paixhans, in particular those for the adoption of shell fire on a large scale, were viewed with much misgiving in this country. but, as already noted, great britain moved very cautiously in the counter-measures which she took in view of the policy then under review in france. it is probable that the publication, in 1828, of a memoir by captain f. a. hastings, r.n., commanding the greek steam vessel of war karteria, had great effect in encouraging the authorities to countenance shell fire. from this memoir it appears that captain hastings was led, by arguments similar to those which influenced m. paixhans, to consider the possibilities of discharging at an enemy something more devastating in effect than the solid sphere of iron in general use. his navy was inferior in numbers to possible rivals; he expressed the opinion that this inferiority might be nullified by the use of175 shell, but he “got well laughed at for his pains.” soon afterwards, however, he came across paixhans’ work. acting on his ideas, he applied shell fire with great success in action, and at once became an enthusiastic advocate of the new arm. one great objection to its adoption he almost laid to rest: the increased danger due to the carriage of shells. he denied that there was any increased danger. on the contrary, he considered charged shells less dangerous than powder in cartridges, if properly packed. they were less dangerous, he argued, because their use involved bigger and therefore fewer guns than an ordinary ship would carry. therefore there was less confusion in action, less jostling, more working spaces, and fewer cartridges and projectiles to be handled. in support of his opinion he could point to an entire absence of accidents during his commission in the karteria.
in 1829 a general increase of calibre was obtained by the inexpensive expedient of boring out guns to their next larger calibre; in which operation the opportunity was taken to arrange for a reduced allowance of windage for the guns thus altered, and thus to secure a double gain, of increased calibre and improved discharge. experiments were made with shell fire à la paixhans. tentative designs of shell gun were produced by the ordnance department, and guns of 8-inch, 10-inch and 12-inch calibre were made; one of which, an 8-inch, mounted in h.m.s. ph?nix, made very effective shooting at san sebastian in the year ’36 and gave thereby an advertisement to shell fire.
and then, in 1837, came the french decision to adopt a shell gun armament generally.
the result was a complete and corresponding reorganization of british ship armament.109 by 1839, the authorities being at last convinced of the necessity of meeting the french innovations with similar innovations on our part, colonel munro’s proposal of 1825 had been adopted, and various classes of ship were equipped with six different patterns of 32-pounder long gun. with these were associated, in small numbers, 8-inch shell guns of fifty-three and sixty-five hundredweight. thus this country by a single move countered the two moves made176 by france in ’29 and ’37 respectively, and denied to m. paixhans, for a while at any rate, any considerable change in the relative strength of the two navies. as in the french navy, shell fire was only introduced as an auxiliary to the solid shot. thus the great ideal of unity-of-calibre, so long sought and at last almost attained, was found incompatible with the other ideal, shell fire; and was therefore sacrificed. no doubt was felt, at this time, as to the necessity for two types of gun. the superior power of shells was dreaded, suspected, half-acknowledged; but the superior range and penetration of solid shot fired from long guns made the latter indispensable to ships’ equipment. so shell and large-bore shot guns were mounted in ships side by side. old guns and carronades were “scrapped” in large numbers to give place to the new ordnance; and an official announcement was made, in justification of the admiralty policy, that “the changes were not made until they had been adopted by foreign powers.”
§
shell fire was at last accepted. the perils associated with the carriage of shells in wooden ships were found to have been exaggerated; experience soon confirmed that, if special precautions were taken, no danger was inherent in their use.
even after its introduction into our fleets the shell gun was regarded by many as of doubtful value. for some years previously the opponents of shells had agitated the question of a compromise: viz. the use of hollow shot uncharged, instead of solid balls. and when m. paixhans had published his great scheme they had held that more advantages would have been offered by it if he had stopped short at charging the shot with powder, and had advocated merely hollow shot, which by their larger size would give the advantages of heavier calibre. but the argument for hollow shot was finally demolished in 1837 by a writer whose views carried great influence. incorrectly attributing to m. paixhans himself the proposal to use them, captain simmons, r.a. proved clearly and conclusively their comparative uselessness. the adoption of hollow shot, he showed,110 would be tantamount to a reversion to the use of stone or granite projectiles; it mattered little, for practical purposes, what the projectile be formed of, so that177 its density be what was desired: whether hollow iron or solid granite. except the turks, who still guarded the dardanelles with granite-firing cannon, all nations had abandoned granite in favour of the heaviest metals, and no one questioned the vast improvement thereby obtained, “except the inventors of the carronade and the promoters of this same system, improved by m. paixhans.” as a matter of fact the carronade was designed for the special circumstances in which hollow shot were not without value. and m. paixhans, as we know, never intended to forego the use of a charge of powder in the cavity of his boulet creux. but the arguments of simmons sufficed to kill the advocacy of hollow, uncharged shot.
doubt was cast, too, on the capacity of the shell gun to project its shells to a sufficient range and with sufficient striking velocity in action. in the case of the first shell guns cast, a strict limitation had to be placed on the powder-charges which could safely be used; and this involved a limitation of range, apart from the reduction due to the lower specific gravity of the projectile. both french and english shell guns suffered in this respect. for this reason they had been deemed by the french specially suited for use in steam vessels, which could by their locomotive power attain the desired range. but, it was said, steam gives the power of avoiding, as well as of closing to action; and steam, it was foreseen, was a giant which would one day haul even ships-of-the-line into position for battle. might not future actions be fought at considerable ranges? and for close-quarter work, could not our powerful long guns, double-shotted, be used with greater effect than shell guns?
then, again, the flight of shells was not nearly so certain as that of solid shot. the effects of eccentricity, which in the case of solid shot had always militated against accurate shooting, were in the case of shells considerably enhanced. the varying thickness of the shell, the lack of homogeneity of the metal, the presence of the protruding fuze, all tended to produce eccentricity and give a bias. the centre of gravity of a shell was seldom at its centre of figure; and this eccentricity was the cause of deviations in flight, in range and direction, which made the trajectory of a shell not easily predictable. savants and artillerists, both here and in other countries, discussed for years these deviations, and on the relationship between range and eccentricity numbers of trials178 were made and theories were propounded. which is the more strange, seeing that robins had placed on record an almost complete solution. briefly, the effect of eccentricity may be explained as follows. just as a stick held vertically by a thread receives, when struck at a point in it other than the centre of percussion, a tendency to motion not only of translation but also of rotation round that centre of percussion; so a spherical shell whose centre of gravity lies away from its centre of figure receives, from the pressure of the powder gases acting at its centre of figure, a rotary motion about its centre of gravity in addition to a motion along the bore. if the centre of gravity lies below the centre of figure this rotary motion is in such a direction that, as the shell approaches the muzzle, points on its upper surface are moving towards the muzzle, points on the lower part are moving inwards. and this rotation, maintained during flight, has the effect—as was demonstrated by robins with the musket ball—of giving the sphere a vertical deviation in a downward direction; i.e. of reducing its range.
it follows, then, that an artificial increase of range could be obtained by placing the sphere with its centre of gravity above the centre of figure? this is precisely what was done; and by many a measured eccentricity was considered a desideratum, as giving a higher range than could be obtained without it. with such a system, however, the deviations still remained large and flights still more irregular. and the best opinion held that the most satisfactory solution lay in reducing the errors of flight as far as possible by the use of perfectly concentric shells. this ideal was difficult of attainment. sir howard douglas has described at length experiments with shells the axis of whose eccentricity was found by floating them in mercury: experiments which revealed that not one shell in a hundred of those supplied was perfectly balanced. for this reason misgiving was felt as to the effectiveness of shell fire when carried out at considerable ranges against solid shot, and efforts were continuously made to correct all shell before issue.
nor were the americans inclined to view the shell gun with much favour; remembering, doubtless, what they owed to their long and powerful guns when they were opposed to our light guns and carronades in the war of ’12 and ’13. america was more cautious even than this country. but in ’41 the 8-inch shell gun appeared in american ships as an auxiliary to the long guns: four or so on each gun deck. and four years179 later the types of guns in their ships were limited to 8-inch shell guns, in combination with 32-pounder long guns of various patterns; in fact, their system of armament was assimilated to that of the french and british.
whatever the relative value of shell and solid shot might be, experience showed that increase in size favoured the former. though medium-sized solid shot might be more efficient than medium-sized shells, yet it was widely accepted that large solid shot would probably be of less value than large shell. strong tendencies were at work, making for such increase in the size of artillery. it was in 1837 that a writer already quoted showed the direction in which the arguments of m. paixhans were leading. citing sir howard douglas on the advantages of large calibre and the inefficiency of random broadsides, captain simmons put forward the argument that, if these statements were accepted, it followed that all ships of war should be armed with a few long guns of the maximum calibre and giving the maximum muzzle energy which the ship could safely carry, with other guns on other decks of the same calibre but of varying weight and range. “instead of determining the armament of a ship from the length of her decks and crowding as many guns together as possible; determining the number by the extent of the battery, and subjecting their nature to their number—making, in fact, the weight and type of gun depend, not on the service demanded, but on the quotient arising from dividing the total deck-weight by the number, previously fixed on; it might be safer to place on board a few of the most powerful guns which her construction would admit, and then regulate the total number carried by their aggregate weight—making the number and not the nature of the guns depend on what is inevitably fixed: the capacity of the vessel?”
the english writer went farther than m. paixhans had gone. his argument foreshadowed the evolution which was so largely influenced by the coming of the steam vessel, with its large paddle-wheels and small crew, and with its deck space necessitating the concentration of its armament into a few guns of the largest calibre; it foreshadowed the supersession of the broadside by the pivot gun, and the enormous expansion in the size of ordnance which took place after the crimean war.
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the evolution of the shell gun was at this partial stage when the crimean war broke out. in 1854 both types of projectiles were still struggling for ascendancy, though large shell guns were by this time acknowledged as the superior armament for steam vessels. both friend and foe were now literally “stormed at by shot and shell”—of which the shell proved on the whole the more effective missile. no decisive superiority could be claimed, however, by one type over the other; and, as we shall see later in surveying the evolution of the ironclad, it was only gradually that the inherent superiority of the shell gun came to be recognized.
soon after the close of the war a new step in the evolution of armament made its supremacy decisive. the rifled cannon at last materialized. the cylinder superseded the sphere. the increase in volume gained by the adoption of this form of projectile, and the enhanced range and striking velocity which it was possible to impart to it, set all doubts at rest as to the military value of the arme nouvelle.
