Chapter III: Artillery (3)

Though the improvements in rifled cannon are at present only in their infancy, they have nevertheless attained to an extraordinary degree of perfection, verifying all our predictions to the letter.

A writer in the _Times_ makes the following statements in favour of Mr. Whitworth’s improvements:--

“While some men of really inventive talent, and a great many charlatans, have been permitted to waste the public money in trying vainly to improve our artillery, it seems passing strange that it should not long ago have been discovered how impossible it was to hope for successful results in the direction in which they were working. It was clear that while increased range and precision of firing were wanted, it was nearly as important to bring the charges of ammunition and the weight of metal in guns into more manageable proportions to each other, and to the facilities for transit on active service. No sensible man can have witnessed the frightful damage done to the efficiency of our army in the Crimea by the exigencies of the siege-train during the winter of 1854-5 without being impressed with this conviction. The principle of the rifle offered an obvious suggestion for the proper means of working out the foregoing problem; but then for artillery, rifling by grooves would not do without the use of a pliant metal in the projectile, and the cost of lead rendered its application to that purpose impracticable. It was necessary, therefore, to alter the existing mode of rifling, and to modify the bore of the cannon, so that an iron projectile could be discharged from it, rotating on its own axis in the line of flight. This result once secured, it is obvious that a field-piece or gun of position would become a rifle on a large scale, and that the same immense increase of range and of penetration which had been realised by the smaller weapon as compared with Brown Bess, would be placed at the command of the artillery service. It is consolatory, after a series of failures worthy even of Brunel in launching the _Leviathan_, that the country has at last the well-grounded hope of an improvement by which our ordnance may be placed on a proper footing. In pursuing those careful experiments which he undertook for the Government, principally to improve the rifle, Mr. Whitworth, the eminent machinist, adopted a polygonal spiral bore of a uniform pitch, but more rapid than could be attained by grooves. This bore has enabled him to surpass immensely the range and penetration of the Enfield rifle; but even these advantages, important as they are, scarcely surpass those which it places within the reach of our artillery service. The strain of the projectile being distributed evenly over every side of the polygon, iron can be substituted for lead in the projectile, and this simple but beautiful mechanical appliance at once becomes available for cannon.”

The powerful aid of the _Times_ is “almost success;” though in this instance it has signally failed, the boasted accuracy there spoken of not having been yet obtained. This has no doubt arisen in part from the fact that Mr. Whitworth’s great mechanical knowledge would not suffice to make him _au fait_ at the compound science of gunnery. His “polygonal spiral bore of uniform pitch, more rapid than could be obtained by grooves,” is after all only an experimental gun, not sufficiently developed as yet for practical utility. Still, the writer already alluded to has favoured us with the following remarks in the _Times_:

“Moreover, Mr. Whitworth has discovered in the course of his experiments, that according to the quickness of the turn in the polygon is the length of the projectile that may be fired; so that 24 lb. and 48 lb. shot have been sent to extraordinary ranges with half the usual charge of powder, from an ordinary 12-pounder howitzer. Here, then, is at once the solution of the whole question which has troubled the brains of so many inventors, real or pretended, for years. The artilleryman at one stride resumes the relative position to the soldier of the line which the Enfield rifle had so perilously deprived him of, and this mechanical country, after finding herself on the level of France, Russia, and other European States, is once more, as during the Peninsular campaigns, enabled to assert her natural superiority in the manufacture of cannon. We trust that no petty jealousies on the part of narrow-minded officials will be allowed to interfere with the course of Mr. Whitworth’s experiments, and that the encouragement which he is now receiving from the Minister at War and the Commander-in-Chief will enable him, at no remote date, to realise for the benefit of the army and the nation that revolution in gunnery which the results already obtained by him promise.”

Report says that 25,000_l._ is the amount of encouragement Mr. Whitworth has received from the Minister of War and the Commander-in-Chief; an adequate sum with which to conduct such an experiment, but not sufficient to insure success.

Of the success of Mr. Whitworth’s polygonal projectile, on a large scale, none need speculate, for the principle is self-destructive.

Lancaster’s oval shell, oscillated in its flight, took a flight so extraordinary, on account of the resistance of the atmosphere on the protuberances of the oval, that the principle may be regarded as fully established that enlarged projectiles must be smooth and free from projections that “saw the air,” otherwise range and accuracy of fire will be sacrificed. The principle of Mr. Whitworth’s polygonal bore is fully discussed in its proper place, and will here receive only a passing notice.

To Mr. W. G. Armstrong, of Newcastle-upon-Tyne, much more credit is due than can be claimed for Mr. Whitworth. Long before the paid efforts of Mr. Whitworth, Mr. Armstrong had made the subject of rifled cannon a special study, and the success of his investigations has been such as to couple his name with those of the earliest inventors of effectual rifled cannon. Mr. Armstrong may also lay claim to being an originator of wrought steel cannon; though here his name stands second as an inventor, for to Mr. Krupp is due the honour of first introducing cast steel cannon to the notice of our Government.

Mr. Armstrong tells his own tale so well in the columns of the _Times_ that we cannot do better than quote it:--

“In the latter part of 1854, I submitted to the Duke of Newcastle, then Minister at War, a proposal for a gun which I anticipated would possess great superiority over the common forms of light artillery, and I undertook, with his Grace’s authority, to construct a field-piece in conformity with the plan I had suggested. The gun was accordingly soon afterwards made, and has since, during a period of nearly two years, been the subject of numerous experiments, partly upon the ordnance firing-ground at Shoeburyness; but principally under my own direction in this neighbourhood.

“I have hitherto avoided publicity in reference to these experiments, but, as matured results of much interest and importance have now been arrived at, and as other names are already before the public in connection with gun experiments made during the same period, I feel that I may now, without impropriety, give some information on the subject.

“With a view to strength and durability, the gun is composed internally of steel and externally of wrought iron, applied in a twisted or spiral form, as in a musket or fowling-piece. The bore is nearly two inches in diameter, and is rifled. The projectile is a pointed cylinder 6-1/2 inches long, and its weight is 5 lb. It is made of cast iron, coated with lead, and is fired from the gun with a charge of 10 ounces of powder; it contains a small cavity in the centre, and may be used either as a shot or a shell. When applied as a shell, the cavity is filled with powder, and a detonating fuse is inserted in front, so as to fire the powder in the centre on striking an object. When used as a shot, the powder is omitted, and an iron point, which favours penetration, is substituted for the fuse. The gun is constructed to load at the breech, the object being not only to obviate the disadvantages of sponging and loading from the front, but also to allow the projectile to be larger in diameter than would enter at the muzzle, and thus to insure its taking the impress of the grooves and completely filling the bore. The piece weighs 5 cwt., and is mounted upon a carriage which bears a general resemblance to that of an ordinary 6-pounder field gun, but which embraces a pivot frame and recoil slide. A screw is also applied, not only for elevating and depressing the gun, but also for moving it horizontally, by which means great delicacy of aim is effected. The recoil slide has an upward inclination, which enables the gun, after running back, to recover its position by gravity; and its use is to relieve the pivot-frame and adjusting screws from injurious concussion.

“I shall now give some particulars of the experiments recently made with this gun on the coast of Northumberland, near the village of Whitley, under the official inspection of Colonel Wilmot.

“Fourteen shots were in the first instance fired from a distance of 1,500 yards at a timber butt, 5 ft. wide 7-1/2 ft. high. Six of these were expended in finding the elevation proper for the distance, but after that was determined every succeeding shot hit the object without previous graze. The final elevation of the gun was 4 deg. 26 min., and the mean lateral distance of the shot-marks from a vertical line through the centre of the butt was only 11-1/2 in.

“Persons who are conversant with artillery practice will be able to appreciate the accuracy of this firing; but, for the information of those who are unacquainted with the subject, I may state that the ordinary 6-pounder field-piece, which in point of weight forms the nearest approach to the present gun, is perfectly useless at a distance of 1,500 yards, and is very uncertain even at 1,000 yards. It is only, therefore, with heavy artillery that a comparison can be drawn; and it will be sufficient to state that in tabulating the practice made with such ordnance the deflections are invariably recorded in yards, whereas with this rifled gun they can only be properly given in inches.

“With respect to penetration, the following particulars will be regarded as equally remarkable, considering the small weight of the shot and the length of the range. The butt was 3 ft. thick, and was composed of six layers of rock elm bolted together, so as to form a solid block. One shot passed entirely through; another struck near the edge and glanced; and the remaining six penetrated within a few inches of the opposite side.

“Shell firing was next tried at a distance of 1,500 yards; the gun being fired at the same elevation and with the same charge as in the previous practice at the butt.

“In this case two targets were erected, one behind the other, so as to appear as one object when viewed from the gun, and a space of 30 feet was left between them. The front target was intended to exhibit the perforations of the shell before bursting, and the back one to show the effect of the fragments resulting from explosion.

“After some preliminary experiments twenty-two shells were fired at the front target, and of these only one missed the object of aim. The following are the particulars:--Seventeen hit the first target direct, and burst behind it, the fragments penetrating the second one; three grazed and burst immediately in front of the first target, and perforated both with the pieces; one hit the bottom of the first target and exploded in the ground, and the remaining one missed entirely and burst on some rocks nearly on line beyond. A strong side wind was blowing at the time, and accounted for the deviation of this single shell.

“Four shells and three shots were then fired at an elevation of 6 degrees, from a distance of 2,000, or, more accurately, 1,964 yards. All these struck within the breadth of the target; but the elevation being scarcely sufficient, they all fell a little short, except one shell, which, ranging somewhat further than the others, hit the target and burst as usual.

“The results of this shell-firing were as follows:--The front target contained 51 holes, and the back one 164, while the ground between and adjacent to the targets exhibited about 70 perforations by fragments of shells, the greater portion of which were afterwards recovered by digging.

“With respect to ranges exceeding 2,000 yards, I may state that on previous occasions the gun had been tried up to 3,000 yards--a distance which was reached with an elevation of 11 deg., and the usual charge of 10 ounces of powder, or 1-8th the weight of the projectile. By augmenting the charge the range is increased, but the accuracy is impaired; and I therefore adhere to the 10-ounce charge, which gives ample penetration, as the experiments at the butt will testify. I may also observe that the ranges obtained with this charge bear a favourable comparison with those of the heaviest round-shot guns fired with a much larger proportion of powder.

“It is a curious fact, and one which greatly increases the efficiency of the shells, that owing to the bursting charge requiring a minute space of time to mature its ignition after the firing of the fuse by impact, the shell is enabled to travel four or five feet after striking an object before disruption takes place. Hence, therefore, it acts as a shot before it bursts as a shell. When it perforates a target the explosion may be seen to take place at a few feet beyond, and when it grazes it has time to rise, and may be observed to burst after clearing the ground. If, therefore, it were fired against a ship, it would first penetrate the side in its entirety, and then, bursting, traverse the deck in fragments; or if directed against troops, it would pierce the front line as a bullet, and operate like grape-shot beyond. The shells explode with equal certainty whether the first substance struck be hard or soft; and, in fact, they even burst on the surface of water, provided the elevation of the gun be not too great. The bursting charge is very small, but it suffices to break the shell into about 30 pieces, which pursue their forward course without too much dispersion.

“It is impossible to contemplate the results obtained with this gun without being impressed with the important part it is calculated to perform in warfare. Opposed to any ordinary field-piece, it would be like the Greener rifle against the old musket; and no gun could be worked at an embrasure if a fire of shells were directed against it by one of these rifled pieces placed within the distance of a mile. In naval operations, also, guns of this description, but of larger size, might apparently be applied with great effect--more especially as a system of breech loading, combined with a self-recovering recoil action, would be peculiarly advantageous in firing from portholes. Even light 5-pounders, sending their shells from great distances through the sides of a ship and sweeping the decks with fragments of lead and iron, would produce very destructive effects; and a small swift steamer carrying a few such guns might prove a very troublesome opponent to a large ship of war. But if the dimensions of the gun were increased so as to adapt it for shells of 20 lb. or 30 lb., still more terrible injury could be inflicted at greater distances; and the ponderous artillery now used at sea would be of little service when opposed to the accurate and long-range firing of such rifled shell-guns.”

Since the publication of these remarks, rifled artillery of Mr. Armstrong’s production has, we believe, been extensively tried. The results of these trials have been most extraordinary; and the principle is, we believe, identical with the expansive principle bearing my cognomen: an extension of the principle of the Greener and Enfield rifle, hereafter to be described. I have had the honour of being consulted both by English and foreign authorities, and I have assisted in constructing rifled artillery for several years; and the experience thus obtained justifies me in making known to the world some of my observations on this subject.

Rifled cannon with elongated projectiles, similar in shape and principle to the Greenerian bullet, give, with charges inferior to those of the old régime and calibre, more than double the range, with ten times greater accuracy.

Now, either of these points, if gained, would be most important improvements, and when combined would produce the most extraordinary results. But this is not all: a great diminution in the weight of the gun might also be effected; and these advantages may be still further extended when we have had time to increase our knowledge of the valuable materials with which we are only just now becoming acquainted.

The following table will show the advantages to be gained both in length and accuracy of range.

Before reverting to the table, it may be necessary to remind the reader that the great reduction in the weight of guns arises from the adoption of the elongated projectile. For example: the diameter of the _elongated_ projectile for an “18-pounder” is much less than the diameter of the gun for the _spherical_ 18-pounder; thus allowing the thickness of metal to be equal in both guns. The gun for the elongated projectile may be greatly reduced in weight without at all diminishing its strength, simply on account of the great diminution in the diameter of the arc.

There is another important fact, which Mr. Whitworth, with all his boasting, has carefully concealed: viz., that a much greater pressure is exerted upon the square inch in the lesser than in the larger diameter of bore; and to conceal this fact, whilst claiming merit for a bullet of 50-gauge exceeding in range one of 25-gauge, the charge of gunpowder being alike in both cases, appears very like deception. Any engineer will tell us that the pressure in the lesser is twice as great as in the larger bore; and this explains why greater velocity is given to the projectile.

With these explanations the reader will be better prepared to weigh carefully my observations. My task would, doubtless, have been rendered more easy, if a clear elucidation of the principles of the expansive bullet could have been given thus early in the work; but it is thought better to do this in its proper place. I will only add here, that although two bullets, one elongated, the other spherical, and of equal diameter, meet with the same amount of atmospheric resistance, yet the one containing twice as much matter as the other retains its medium velocity nearly double the distance. With these explanatory remarks I give the following table:--

------------------+-------------+-------+--------------+----------
|Present Range|Present|Reduced Weight|Range when
|of Guns. |Weight.|when Rifled. |Rifled.
------------------+-------------+-------+--------------+----------
6-pndr. | 1,500 yds. | 17 | 12 cwts. |3,000 yds.
9-pndr. | 1,600 „ | 26 | 18 „ |4,000 „
12-pndr. | 1,700 „ | 34 | 22 „ |4,500 „
18-pndr. | 1,780 „ | 42 | 29 „ |5,000 „
24-pndr. | 1,850 „ | 50 | 34 „ |5,500 „
32-pndr. | 2,000 „ | 63 | 42 „ |6,000 „
48-pndr. | 2,500 „ | 70 | 45 „ |6,500 „
56-pndr. | 5,000 „ | 85 | 60 „ |8,000 „
68-pndr. or 8-in. | 4,500 „ | 85 | 60 „ |8,000 „
86-pndr. or 10-in.| 4,700 „ | 95 | 65 „ |9,000 „
------------------+-------------+-------+--------------+----------

The reader must understand that all the guns given in this table were not rifled, and that they have not all been subjected to trial. The 6, 12, 18, 24, and 48-pounders have been tried, with the results given above; but the heavier guns have not as yet been tested: the ranges and weights given in the table have, however, been derived from the results yielded in the trial of the lesser guns, and may be safely relied on as scientific data; being, in truth, rather under than over the mark.

All experiments clearly establish one very important principle, long known to those acquainted with the science of projectiles, viz., “That the heavier the projectile, the less the deflection.” Thus it is quite possible that the longest ranges may ultimately be obtained without any perceptible deflection. And when we observe that the deflection of an ordinary 32-shot in a range of 2,000 yards, is 50 feet, and in 2,500 yards, 80 feet, whilst the elongated shot, at a much greater distance, is not deflected half as many inches, I think we may fairly say that our knowledge of gunnery is yet in its infancy. Fulminating powder may be used as an auxiliary in shells for various important purposes; such, for instance, as destroying an entire fleet; and it is clearly within the range of possibility that by its agency the largest ship may be destroyed by a single shot. The accuracy of rifled cannon renders it an easy task to strike a plank only one inch above the water line, and the penetration of an elongated gun-metal or lead-alloyed shell would enable us to reach the innermost parts of the magazine: for it is scarcely possible to produce even an iron casing which shall resist the power of such projectiles. It is possible, therefore, that we may see the noblest fleet destroyed in a few minutes by the agency of such projectiles.

I will endeavour to give an outline of the method by which this may be effected. A long rifled cannon, constructed for an elongated gun-metal shell; of from fifty-six to eighty-six pounds, and with an extreme range of from 6,000 to 7,000 yards, may be considered to be a suitable instrument. This shell should be charged in the head with a given quantity of the fulminate, such as would be most calculated to prevent the tendency to explode from the concussion produced by the discharge of the gun. It will be necessary to place the fulminate in thin layers between sheets of prepared caoutchouc, or some other preparation of India-rubber; having thus arranged the fulminate in the head of the shell and secured it there, the usual method of filling the remainder is resorted to, and the aperture is securely screwed up: fuses not being necessary in this arrangement.

The difficulty in using this shell is to prevent its explosion when the gun is discharged; and to obviate this all our engineering skill is required. Time and experience will show that, by a modification of the propelling agent, the shell may be started from a rifled cannon at a very low velocity; the velocity being increased like that of the rocket. This is to be done by modifying the arrangement of the gunpowder so as to ensure the shell acquiring its greatest velocity as it leaves the muzzle of the cannon. The result of this has been already shown. On the shell striking any object, such as the ship’s side, the metal of the shell is driven in upon itself, and an explosion of the fulminate follows as a natural consequence. Experiment has proved that shells exploding as they strike the ship’s sides, produce very little damage beyond making a hole in the ship the size of the shell. This, no doubt, arises from the short space of time occupied by the shell in passing through the side of the ship; all its force being exerted in the interior instead of on the sides of the vessel. All shells of the nature alluded to would, at certain distances, take such a line of flight as to ensure them dipping towards the centre of gravity, and thus exploding the magazines, however deep below the water-line; and when we consider the destructive effects of fulminates, we think it quite within the range of probability that they might produce all the effects we have spoken of.

There are many agents equally powerful to be introduced into destructive warfare; and with the advantages to be derived from improvements in rifled shells, which the ingenuity of the present race will certainly effect, he would be a rash man who would set any limits to the advancement of projectile science. The great difficulty in the use of fulminates will be surmounted if these suggestions can be carried out; and experiment is all that will then be necessary to establish the line of proceeding. To effect this is the province of the Government of the country; to wait for it to be perfected by individual skill and enterprise would be unjust to science, and injurious to the best interests of the nation. The needful expenditure can only be borne by the nation, and should be entered upon, in order to effect improvement in projectiles, with the view of maintaining our land and marine artillery at the highest point of efficiency.

There is one question of great importance to inventors, and to which I have paid much attention, namely, the obtaining a spiral motion in a projectile which has been fired from a smooth bored gun. All we have witnessed goes far to prove that the attainment of this is impossible, in consequence of a principle not hitherto investigated by inventors. If the course of a projectile is changed from the straight to the spiral, it can only be done at the expense of range; and that for the following reasons: first, the force which is necessary to induce this spiral movement must be exerted at the expense of the force which propels it forward; secondly, when this spiral movement is acquired, it is so much in excess of the direct movement, that after advancing a certain distance it falls to the ground. A very simple experiment will prove this. Take an ordinary tin tube, cut a bullet of an elongated form--cylindro-conical if wished--having grooves from the point backwards, with the degree of spiral necessary to effect the object in view. Let the bullet be made of cork or light wood, such as can be projected by a blast from the mouth, and the result will be that the projectile will go one-half the distance before the friction of the atmosphere produces a motion on its axis parallel to its line of flight; from this point it gradually loses its velocity in a forward direction, it spins until its force is expended, and then falls vertically to the ground. To find the sequel, try the same experiment without grooving, and the range, with the same force, will be found to be double. Some years ago I witnessed such a trial with a 32-pounder; and, to the astonishment of all present, the bullet rose above the horizontal line, and then fell to the ground, like the cork bullet of which we have already spoken.

The endeavour to produce breech-loading cannon is an effort to obtain uncalled-for and superfluous facility in gunnery; and if a perfect breech-loading cannon could possibly be produced, what would it avail? What superior property could it possess over the solid gun? It could not be safety; for when we consider the very limited number of explosions by which the very best guns are destroyed, it can scarcely be possible for a gun composed of many parts to endure the intense vibrations to which large cannon are subjected. The regular distribution of vibrations in the metal of the gun is the great point to be attended to in the construction of artillery; so that vibrations may not be incorrectly induced by malformation, or by an excess or deficiency of metal at any particular point; for where the waves of vibration are checked by an unequal distribution of metal, or other causes, there the weak point in a gun is always found, as all fractured guns clearly demonstrate. An intimate acquaintance with the metallurgy of cannon, enables me to give an almost unerring opinion as to the causes leading to the fracture. Most undoubtedly, vibration, if judiciously distributed, is the soul of endurance; but if injudiciously distributed is certain to result in the destruction of the cannon. In structures composed necessarily of many joints, obstruction to the waves of vibration must occur; the different parts do not expand and vibrate equally; a kind of revulsion is induced; part repels part, and destruction ensues as a natural consequence. Under no circumstances, therefore, can a breech-loader be as safe as a solid gun.

The facility with which breech-loaders can be charged is generally trumpeted forth to the world as an advantage of vital importance; but let us carefully examine this point and see if it has not been exaggerated--whether, in fact, a solid gun cannot be charged and discharged as rapidly as a breech-loader.

In the first place, all guns recoil; this necessitates the relaying of the gun after every discharge, in order to obtain accuracy of aim; and if facility of loading is to be obtained at the expense of aim, it can scarcely be called an advantage. Aim consumes more time than loading. A six-pounder may be loaded and fired six times in the first minute; but it would be impossible to do this and re-lay the gun after each shot. Where then is the advantage of firing six shots per minute if you cannot hit six objects? And if breech-loaders could be fired _sixty_ times per minute, what would they avail if aim was wanting? The raising or depressing of the breech of a gun by means of the elevating screw; slewing to the right or left, spunging the gun, and ramming home the powder and shot, all consume time; hence we think that quickness of loading is worthless.

Breech-loading cannon cannot be constructed for bullets of larger diameter than that of the rifle bore, without a ductile bullet be used; for, as is usual in breech-loading small-arms, the bullet rifles itself as it is forced up the grooves. The projectiles for rifled cannon have hitherto been cast with corresponding grooves and lands to fit the internal form of the cannon. A compound shot, composed of iron, and covered externally with ductile metal, has been tried in a few instances; but, unfortunately, the difficulty of combining two metals so dissimilar as iron and lead has been found so great as invariably to end in a failure; therefore no prospect exists of bringing into play this, the best point existing in breech-loading arms.

Lastly, the tendency of all guns to absorb the heat, developed during explosion, puts a limit to all extreme rapidity of fire; even if this was not already limited by the more essential point of taking aim. At Sweaborg it was found necessary to allow an interval of five minutes between each discharge of a mortar, and yet the whole of them burst after an average of 120 shots. Time and ingenuity spent in planning and constructing breech-loading cannon will always end in disappointment and failure. Many are the plans extant, evincing great skill, perseverance, and everything needful in point of mechanical experience, but betraying a total ignorance of the metallurgic science and of practical results from the use of the engine. The study of these points will save money, time, and what is of more value, brain-work, which might be better employed. Striving to produce perfect breech-loading cannon is like striving to square the circle.