N.B.—Revolving Arms of the Fifth Class shall be proved once only, and such Proof shall be by the Scale laid down for definitive Proof of the Fourth Class.

As soon as a number of gun barrels are loaded according to the foregoing scale, they are taken to a house or detached building, standing apart from other offices. (The woodcut represents the interior accurately.) The house is lined throughout with thick sheet iron, and the windows, which resemble Venetian blinds, are constructed of the same metal. Iron frames are laid the whole length of the room; on these the barrels of various qualities, when about to be fired, are placed. In the front of these frames lies a large mass of sand, to receive the balls. Behind the frame, on which the twist barrels are fixed, lies another bed of sand; in which, on the recoil, the barrels are buried. Behind the frame, on which the common barrels or muskets are tried, a strong iron bar is placed, having a number of holes large enough to receive the tang of the breech, but not the barrel. The barrels being thus fixed, it is impossible for them to fly back. A groove runs along the whole length of each frame, in which the train of powder is strewed to ignite the charges, upon which the barrels are laid, with the touch-holes downwards.

When everything is ready for the proof, the windows are let close down, the door is shut and secured, and an iron rod heated red hot is introduced through a hole in the wall. On igniting the train, a tremendous explosion takes place. The windows are then drawn up, the door opened, and the smoke dissipated. The twist barrels are found buried in the sand, the common ones are thrown forwards; some are found perfect, others burst to pieces. It is rarely that best barrels are found burst; more frequently they are bulged, or swelled out, in places which are faulty, or of a softer temper. Those that are found perfect, are then marked with the provisional punch of different sizes (but having the same impression), according to the quality of the barrel. In London and Birmingham they have now an additional punch, containing the number of the bore by which the barrel has been tried. This mark easily enables the observer to discover whether the barrel has had any considerable quantity bored out after proving. Those that are bulged are sent to the maker, who beats down the swellings, and sends back the barrels to be proved again. They generally stand the second proof, though we have known a barrel undergo four proofs before it was marked. The common barrels are required to stand twenty-four hours before they are examined; when, if not burst, any holes or other material imperfections are made quite apparent by the action of the saltpetre. Such barrels are, of course, sent back unmarked. Those that are found satisfactory are duly stamped and taken home.

The importance of the gun trade to England may be estimated from the number of barrels proved during the last year, 1857, of which the following is a correct statement:—

Provisional Proof.

This is in Birmingham alone; no doubt the London Company prove to the extent of 200,000 yearly, which may also be debited to Birmingham, as the barrels are all welded, bored, and ground before being sent to London. In addition to these may be counted the Government contracts of some hundred thousands yearly.

The passing of this Act of Parliament levelled all distinctions between London and Birmingham proved barrels; they are now treated precisely alike, and one is equally good with the other.

CHAPTER VII.
THE SCIENCE OF GUNNERY.

A new era in the science of gunnery may be dated from the commencement of the latter half of the nineteenth century; and long before its close other improvements may be effected which shall eclipse even those of our day. A new elementary principle has been infused into the science. Rifles are now really weapons of the highest order; in truth we may be said to have only recently become acquainted with the principles on which they should be constructed. Little of science had hitherto been applied to them; as military arms they were neglected for centuries, to be ushered into notice at last by the unassisted efforts of private individuals; Government, to whom arms were of the greatest importance, having systematically neglected all improvement, by invariably refusing pecuniary aid, the only grease at all calculated to overcome the friction retarding the wheels of progress. It is an old proverb, that “one extreme begets another,” and when changes are once started, the difficulty is to stop them; the tendency is to rush on from one alteration to another, before we are really well acquainted with what we have so hastily thrown aside. Improvement does not always follow a change; the human race, and the English more especially, have an inordinate desire for “the marvellous;” and multitudes of “wonderful discoveries” and inventions of the utmost value are heralded daily by the ever eager press, often to be as hastily forgotten, or discovered, even by their promulgators, to be myths.

Improvement, to be at all beneficial, must bring with it all the elements of improvement; and to render it easy of attainment, none of its essential points should be costly. In gunnery more especially, it is essential to avoid all unnecessary friction, excess of recoil, and waste of gunpowder; whilst, at the same time, transport of the gun must not be cumbersome, and durability in all its points is essential.

How few study the subject in all its bearings! How rapidly conclusions are jumped at! Even in getting range, if it is to be purchased at the cost of other essential principles, it is not economy to sacrifice several even moderately valuable principles for the sake of range alone. The experience of the present age has shown that all our important discoveries have their limits: the locomotive cannot be used with advantage beyond a certain limited speed; steam vessels attempted to be propelled at an unusual velocity have but a very brief endurance, and rapidly decay. All matter has power only to effect a certain amount of work, and this is endured best at a medium application; showing most clearly that “the race is not always to the swift or the battle to the strong.”

Experience is required in the greatest of modern inventions. Electricity, at a moderate immersion, subjected to a moderate superincumbent weight, is an effectual messenger, swift as thought; but when overweighted by immersion to depths where the superincumbent pressure amounts to thousands of pounds upon the square inch, then the messenger becomes paralysed, and refuses to obey man’s will; showing very clearly that until that pressure be artificially removed by insulating the conducting wire in tubes equal to restrain or keep from it that enormous load, the lasting success of an Atlantic telegraph is very doubtful. Many similar instances might be cited to show the necessity of considering well the established laws of nature, and their bearing on the object pursued. In no science is this of more importance than in gunnery; and the hundreds of useless inventions in gunnery are to be ascribed to the non-observance of these rules. The two-grooved rifle, the “steam gun,” “the sciva,” “Warner’s long-range myth,” and many other inventions equally absurd, engage the attention for a time, but soon vanish: in fact, all experience shows that improvement can only be effected in accordance with certain established principles of nature and practical science.

Iron, in quantities sufficient for all reasonable requirements, is a dutiful servant; but, when required of colossal proportions, it refuses to obey: giving us a hint from nature, that we should be content with moderation.

All the principles appertaining to science are based on certain established laws; the unsoundness of one renders the superstructure unsound also; and any deductions drawn from unsound principles are comparatively worthless. Gunnery, as a science, must be in uniformity with truth in all its parts, or no science exists in its arrangements. This will be best illustrated by dividing the subject into several heads: 1st, the explosive power and its velocity; 2nd, the retarding agents, air and friction; 3rd, the construction of the projectile tubes; and 4th, the form of projectile best calculated to attain a perfect result.

1st. The explosive power. Gunpowder has been stated by different authorities to liberate its gases with very different degrees of rapidity. Hutton has given to it a much greater rapidity than Robins has evidently even surmised; though, no doubt, as we have already shown, high velocity in gunpowder depends on several circumstances—the degree of purification of its ingredients, their intimate mechanical mixture (that the elements may exert their affinities with the utmost facility), and, lastly, the degree of granulation observed: and in addition, the suitability of the tubes or vessels for carrying on correctly such important experiments. Robins and Hutton unquestionably may be regarded as the English, if not the European, authorities, and any work on the science of gunnery would be very incomplete without their valuable elucidations.

Previously to the researches of Robins, the theory of atmospheric resistance was but imperfectly surmised, and when he made his statements of the immense resistance which the fluidity of the air offered to projectiles in a high state of velocity, they were treated as the idle chimeras of a speculative brain; and yet he only was enabled to estimate the real effect of the explosive nature and force of gunpowder to a very limited extent: indeed, so limited, that Hutton, only twenty years subsequently, speaking of Robins’ theory, says, “Mr. Robins and other authors, it may be said, have only guessed at, rather than determined. That ingenious philosopher, in a simple experiment, truly showed that, by the firing of a parcel of gunpowder, a quantity of elastic air was disengaged; which, when confined in the space only occupied by the powder before it was fired, was found to be nearly 250 times stronger than the weight or elasticity of the common air. He then heated the same parcel of air to the degree of red hot iron, and found it in that temperature to be about four times as strong as before; whence he inferred, that the first strength of the inflamed fluid must be nearly 1,000 times the pressure of the atmosphere. But this was merely guessing at the degree of heat in the inflamed fluid, and, consequently, of its first strength; both which in fact are found to be much greater. It is true that this assumed degree of strength accorded pretty well with that author’s experiments; but this seeming agreement, it might easily be shown, could only be owing to the inaccuracy of his own further experiments; and, in fact, with far better opportunities than fell to the lot of Mr. Robins, we have shown that inflamed gunpowder is about double the strength that he has assigned to it, and that it expands itself with the velocity of about 5,000 feet per second.” On the same subject he further says:—“On this principle it was that Mr. Robins made all his experiments and performed all his calculations in gunnery. But it is manifest that this method of guessing at the degree of heat of the flame must be very uncertain and unsatisfactory, being much below the truth; since all our notions and experience of the heat of inflamed powder convince us that it is higher than that of red hot iron, and, indeed, it has clearly appeared from our experiments, that its heat is at least double that of red hot iron, and that it increases the elasticity of the elastic fluid more than eight times.”

Here is evidence, though not conclusive, of the immense force of gunpowder, and also of the progress of knowledge on the subject; yet it clearly shows the evil of coming to hasty conclusions, however well supported by apparent facts, as it has had in this case a tendency to check inquiry and retard the advancement of knowledge. For the extensive experiments of Hutton were but limited in discovery, because they were not carried to a sufficient extent, and thus, they are quite unsuited to the present day. He was satisfied because he had gone further than any of his predecessors; and though he established and clearly proved the soundness of his own theory, yet he could not either view the subject to its utmost bounds, nor yet go sufficiently far, but that others, taking up the question where he left it, may pursue the subject to a much more remote limit. The subject, indeed, was limited to him. He far excelled Robins, no doubt, as he has shown; but that involves no detraction from the merit due to Robins for his experiments and discoveries, no more than any individual proving the subject to be a more extensive one than Hutton did, would excel Hutton; for the value of improvement is more to be attributed to him who lays the foundation, than to him who raises the building. So is it in this case; Robins laid the foundation for an extensive knowledge of the nature and power of the explosive fluids, and Hutton built upon that foundation a certain extent of superstructure, and there he left it, without roofing the building: he considered the question as settled. Common consent has, as yet, received his conclusion as unshaken and uncontroverted; and it is not my intention to make the attempt to controvert it, but merely to show that his deductions fall short of what the principles of gunpowder-making admit—carried out in the more extensive way it has been within the last few years—owing to the limited nature of his experiments. This is rather an extensive position for me to occupy, or endeavour to hold: but I do not mean the size of the tools of experiment so much as the diversity of them; for exploding ten thousand tons of powder in the same machine and in the same way, would but give the same or similar results; it is the variety and the singularity of experiments that expand and increase the fund of knowledge, and enable the mind to conceive and comprehend the immensity of the power and velocity of this wonderful combination. We have been principally indebted to the exertions of the chemist for means of purifying and extracting from the ingredients which form this astonishing compound force, the impurities and foreign substances which exist, to a certain extent, in all the three, and thus tending to form a more perfect combustion by increasing the affinities.

Hutton shows that gunpowder is but so much condensed air; for he says “We may hence, also, deduce the amazing degree of condensation of the elastic air in the nitre and gunpowder, and the astonishing force experienced by its explosion. It has been found by Mr. Robins, and other philosophers, that 3-10ths of the mass of the powder consists of the pure condensed air, or that the weight of the condensed air is equal to 3-10ths of the whole composition. But the whole composition of the powder consists of eight parts by weight, of which six parts are nitre, one part sulphur, one charcoal; of which the nitre or 3-4ths of the composition furnishes the whole of the condensed air, while the sulphur and charcoal only give the fire that produces the explosion. But 3-10ths of the whole mass of eight parts is equal to 4-10ths of the six parts of nitre, that is 4-10ths or 2-5ths of the nitre consists of condensed air, or the weight of the gross matter in the nitre as four to six, or as two to three; and these two parts, it is probable, are of equal density or specific gravity. Yet the specific gravity of nitre is 1,900, that of water being 1,000, and of air 1·2, which is contained in 1,900, as much as 1,583 times; that is, the air in the nitre must be condensed the amazing quantity of 1,583 times, if its specific gravity be equal to the compound nitre itself.” Also, “The air is condensed in the nitre about 1,600 times, nearly double the density of water, which may well be considered as probably the greatest degree of compression that air is capable of. Hence it may be perceived that a prodigious force must be exerted by nature in generating nitre; and as this great force actually exists in nature, it is very probable that the air in the nitre is thus compressed into the most dense state possible, and in this consists the similitude among the different particles of nitre.”

This extract from Hutton enables us to divest the question of any technicalities, and puts it in so plain a garb that the simplest mind may comprehend it. Now, the great improvement of chemistry has been to extract from the nitre the gross material which is contained in the proportions—2-5ths impurities, and 2-5ths condensed air; thus, half the quantity being useless, the extraction of these alloys gives a greater quantity of condensed gases in the same quantity of matter; for if we take away 2-5ths of the proportions of useless matter, and supply its place with 2-5ths more condensed air, we thus get 4-5th explosive matter in the same bulk of material, and thus simply obtain an immense increase of power without an increase in bulk. We have here evidence of the progress that has been made in the science of explosive force.

Considering the difference between gunpowder in 1783 and gunpowder in 1858, I cannot say, with Hutton, that the force is doubled now to what it was when he wrote; but I believe that this would not be far from the truth; for it must be quite clear—if he is correct (which I believe he is) in saying the force of gunpowder consists in the quantity of explosive matter let loose and expanded by heat—that the greater the quantity of condensed matter we may have in any given weight, the greater the force, and the more rapid the explosion: purified saltpetre thus forming nearly pure gaseous matter; as the diamond is pure carbon. It seems singular, and is rather presumptuous to say, that Hutton was not much of a chemist; but had he been more so, he must have perceived that in the extraction of the foreign matter from the nitre, existed the means of obtaining an increased quantity of explosive power, and a proportionate increase of speed or velocity in that explosive material.

To ascertain the velocity best suited to all projectiles, constitutes the germ of the science; and that we are approaching a new era in even that more intimate portion of the science, is daily apparent. Science shows clearly that if a given force, a quantity to be correctly ascertained, can produce a certain result, the use of more is waste, and unworthy of the seeker after perfection; and thus we have to determine upon, or define, what is the degree or size of gun for certain effects: a mere calculation nearly allied to that portion of engineering which would define what power of engine would work a thousand cotton spindles, or raise a million gallons of water; and all this will eventually be done. Science requires that there should be no excess, no waste, no unnecessary recoil, and all that combined with the utmost range of projectile; this will have to be defined accurately before we can clearly or truly say we are masters of the science of gunpowder. True it is that the granulation of gunpowder gives a clear road to its attainment; but it will be a wearisome journey to reach the summit: yet it must and will be effected, and the nation that first attempts and carries out the attainment, will evince a real love for and mastery of science.

The following practical experiments illustrate the degree of velocity and the effects of projectiles so clearly, that they alone will convey some idea of the high velocity of the evolutions of the gases in gunpowder.

My experiments are, like Robins’, on a small scale; nor would I, like Hutton, try a brass gun of sixty calibres in length, carrying a one-pound ball; for one is strictly more limited than the other, and thus rendered the results laid down by him imperfect: for, as he says, “If you fill the tube with powder you get no greater velocity, as there is not a duration in the confinement to enable the powder to explode.” If he had assimilated the grain of his powder to the gun, he would have obtained a different result; and a knowledge of this fact, I apprehend, makes all the difference. The greatest velocity he obtained was with powder 1¹⁄₂ times the weight of the ball in a gun of sixty calibres in length, and the velocity he then obtained was only 3,181 feet per second. The inferences that probably induced him to recommend others not to endeavour to obtain a greater velocity than 2,000 feet per second, were, like these experiments, drawn from imperfect data. With a ball of an ounce weight in a barrel of sixty calibres, and with 3-4ths the weight of ball in powder, or 12 drachms, a velocity can be given to the ball to equal it in force to 46,875 pounds. The velocity of this ball I leave to the calculations of the mathematical world. But, however, I will give the results of a round of experiments tried to ascertain this; and if the data laid down be correct, that the velocity of a ball must be multiplied by its weight to find the force, the result will be the establishment of a system of velocity never yet dreamt of. I cannot but imagine that there exists some error; though where it is I know not: every deduction I have drawn is consequent upon the results hereafter described.

“The power required to force a punch 0·50 inch diameter through an iron plate 0·08 inch thick is 6,025 pounds, through copper 3,938 pounds. A simple rule for determining the force required for punching may thus be deduced:—

“Taking one inch diameter and one inch in thickness as the units of calculation it is shown that 150,000 is the constant number for wrought-iron plates, and 96,000 for copper plates.

“Multiply the constant number by the given diameter in inches, the product is the pressure in pounds which will be required to punch a hole of a given diameter through a plate of a given thickness.”

Now an idea struck me, that this would form a very good test of the comparative force of gunpowder, and I consequently commenced an extensive round of experiments.

In the first attempt I found the results to vary with the weight of the pendulum of iron plate, and that it was necessary to obtain uniformity of size and surface; as it must be comprehended that the only resisting medium to the pendulous plate was atmospheric resistance, and a dissimilarity of size of surface would invariably give different results. Having a number of plates of the different thicknesses hereafter described, I continued increasing the charge from a definite quantity, until the projectile was driven with sufficient velocity to perforate the plate suspended. The gun selected for this purpose was of heavy material, weighing nearly seventeen pounds, it was three feet long, the metal of the barrel as thick at the muzzle as at the breech, and carried a spherical ball of sixteen to the pound, or one ounce, and which fitted tight with the thinnest patch procurable. The bore was perfectly cylindrical, and plain inside, being polished longitudinally to a high state of fineness. With a charge of twelve drachms of Curtis and Harvey’s diamond grain powder, the ball went through the half-inch plate, but went only a few yards further; denoting that the effort necessary had nearly exhausted its velocity and momentum.

The recoil of the gun was of the most severe description, and the shoulder had to be protected for many explosions previous to this high charge. The larger sized grain was insufficient, ten drachms effecting the greatest extent of power it seemed capable of, and it became quite apparent that the tube would not explode more powder, as indications convinced me: when any more was added, a portion came out unburnt.

The force necessary to effect this, by the above calculation, is 46,795 pounds.

The next plate was 7-16ths thick, and a charge of ten drachms punched the piece out clean; nine and a half drachms were equal to it, when the centre of the pendulum could be hit fairly, because there was then an equal resistance from the atmosphere, which cannot exist in cases where the edge of the disc receives the blow.

I got with ease a perforation in a 6-16ths plate, with a charge of either fine or coarse powder, not exceeding eight drachms; a charge of seven drachms of fine grain was unequal to the task; but seven drachms of the coarse showed evidently greater effects produced, though the perforation was not perfect. Six and a half drachms of No. 2 grain penetrated a plate of 5-16ths thick easily, while it took full six and three-quarters drachms of fine grain; five drachms of the larger perforated a quarter-inch plate, but it took full five and a half drachms of fine grain to effect the same; while a 3-16ths plate took three and three-quarters drachms of fine, or three and a quarter of No. 2 grain; and 1-8th plate was easily punched by a charge of two and a half drachms coarse or three drachms fine. I will place the relative results in a table, with the force effected by each:—

Were I to adopt the established method of calculation, multiplying the weight of ball by the velocity, I should get an answer that would point to the utter impossibility of any such velocity being possible. And yet the result is, according to the rule of figures, correct; but in truth there are exceptions to many rules, for they are only correct when applied to known products.

That the velocity of these balls was much, very much, greater than 7,000 feet per second of time, there cannot be any doubt; it was nearly three times that. Yet I must not conceal the fact, that this punching is the more perfect, the higher the velocity; and it shows how the fibres of iron are separated from a want of vibration to equilibrise the cohesion. Mr. Colthurst found that duration of pressure lessened the ultimate force necessary to punch through metal, and thus it may be that extremely quick pressure may produce the same. Therefore I suspect it is not the most correct theory that calculates force to be accomplished at all times by extreme velocity; there will be found discrepancies in the rule, and one of them arises from no calculation ever having been made with extreme velocities: medium velocities may generally give such conclusions, but the very extreme in this case can never have been taken into consideration at all; as I have very little doubt—in fact, I am certain—that no person ever obtained such high velocity before. It must, and is a vast deal greater, incomprehensibly greater, than any velocity obtained by Hutton; and much more extensive than ever could be obtained, or, in fact, ever will, by any ordnance whatever. I wish much I could have experimented with a gun of greater length and bore, for with one in every way fitted for the purpose, I have no doubt of being able to perforate an inch thickness of plate.

Should any person possessing the opportunity and means, wish to try the experiment, I would advise them to get a barrel of 4¹⁄₂ feet long, 8 bore, to carry a 2 oz. ball, and of a weight to allow of extending the explosion up to 30 drs. of powder; they would then obtain the extent of force I have suggested. There is a certain point to be strictly observed: see that the plate you use is perfectly sound; for if laminated, or composed of various plates not firmly welded and attached, the experiment would be imperfect, as there would be an uneven vibration created, and acting as the hammer does when held against the point of the nail while driving it in, clinches the point, so does the substance in the portions of plate prevent a perforation. An ounce ball, suspended against the back of the pendulum, by the jar or blow it receives and communicates, completely prevents the effect, and the ball is flattened, instead of perforating the object struck: so is it if you place a ¹⁄₄-inch plate against any support; it thus has the power of perfectly resisting the force of the ball, though fired with considerably more power than is requisite under other circumstances. The effect appears to be chiefly mechanical; the outer fibres are driven in upon those behind them with such quickness that they lose cohesion, or are condensed quicker than the waves of vibration travel, thus giving them no means of communicating the vibration. But when punched, the rapidity of their motion produces in the metal a sound of the most intense vivacity, which plays upon the ear for a considerable period, with rather a pleasant effect. Lead alone is capable of being used in this experiment; except, of course, the precious metals, which it would not be convenient to use. Even an adulteration of the slightest quantity of solder is sufficient to prevent the result which lead, pure, will invariably give. Lead projected against lead, if sufficiently thick, cannot perforate, but the lesser portion becomes flattened; a cast-iron ball fired against lead, with a certain velocity, is broken into pieces, affecting the lead comparatively little: showing beautifully the peculiarity of dense incompressible bodies to resist most effectually the greater the velocity with which they are struck. Water will, if struck very sharply with the flat of a sword, act against the blow in a way to splinter the blade into pieces. The greater the velocity with which a ball is fired into water, the less the depth of penetration; thus showing clearly the many excellent properties of dense incompressible bodies as projectiles, and proving the objection that lead is too soft for artillery to be without a foundation, and only entertained from a want of knowledge of its nature.

A point of great importance was exemplified during these experiments; and as the question has lately given rise to considerable discussion, it will be well that the facts should be stated.

At very short distances from the muzzle of the gun the penetration was found to be less than at distances more extended. At five yards the iron plate could not be perforated; at ten yards the effect was much greater, but fifteen yards was the least distance at which it could be said to be effectually perforated; at twenty yards the result was still more satisfactory, clearly demonstrating that bullets gain both in velocity and penetration for a considerable distance after leaving the muzzle of the gun. The following experiments verify this remark:—

In the report of the experiments which were carried on at Cork in 1852, it is stated that the power of penetration of an elongated rifle bullet gradually increases as the range is increased, up to 190 yards.

In order to prove this, experiments were carried on at Enfield for three days with a variety of fire-arms, and different sorts of projectiles. On the fourth day the experiments were repeated with the common musket and Wilkinson’s rifle. The former, at forty yards, gave a penetration of 2·25 inches; and the latter averaged 2·75, in a target of green elm. Again: at ninety yards, the musket penetrated 2·25 inches, and the rifle 3·5 inches. At 120 yards, the musket gave 2·5 inches, and the rifle 3·25. Both being subsequently fired at every successive ten yards up to 220, the result was that the penetration of the musket ball gradually decreased in power as the distance increased, while the elongated bullet gained power of penetration up to 190 yards; after which it slightly decreased.

2nd. Consequent on the velocity of the explosive fluids is the resistance of that aëriform fluid filling all space. It has been calculated that in a vacuum, matter in motion would be a long time in coming to rest; and very providentially it is that nature in her grand arrangements has made one element to control another. In no other portion of nature’s work has anything more wonderful than atmospheric air been produced; its action on the velocity of projectiles is of so extensive a nature, that without clearly understanding that action, the science of gunnery never can be thoroughly acquired. The resistance of the atmosphere is in proportion to the velocity of the attempt to displace it; the higher that velocity becomes, the greater is the resistance. This is shown by the actions of all the fulminates. A quantity of the fulminate of silver exploded on a copper plate will perforate that plate, or, if fired upon a piece of wood, will bury itself in that substance, splintering it in proportion to the quantity. Now, ordinary gunpowder has no such effect as this, because, though it may produce the same amount of expansive gas, it produces it at one-fourth the velocity of the fulminates: the air is driven back upon itself so gradually as to offer no very important resistance; but the action of the fulminates is so rapid and so violent that the high elasticity of the air has not time to yield, and the force is driven into the apparently more solid material, the copper or the wood.

The mode in which atmospheric resistance mostly interferes with projectile force is owing to the columnar form it assumes in the tubes of all descriptions of gunnery. If the velocity of gunpowder be as great as we suppose it to be, the displacement of a column of air must be effected by driving the whole column in a gun-barrel of many inches, into a column probably less than half an inch in height; or, if the length of the tube from the starting of the charge to the muzzle be 38 inches, then will the displacement require a force capable of condensing thirty-eight atmospheres into one, or something like 570 lbs.; without estimating the lateral pressure of that column on the sides of the gun-barrel, which may be safely estimated at one-half more. It may be supposed that the column would be partially in motion for a greater distance than half an inch in front of the projectile; but this is disproved by the fact that time is essential to put aëriform matter in motion, and naturally it never does so at a greater velocity than it is familiarly known to do in the shape of winds: but the fact is better illustrated by the frequent bursting of barrels near the muzzle, caused by a piece of snow or clay, a piece of paper or wadding. Were a current established around this projection it would pass on, but the air strikes these light obstructions when in a high state of condensation, amounting to many atmospheres in one: so many as to be nearly equal to a solid which is more powerful than the barrel; the latter therefore succumbs to it.

The resistance of the air is so highly philosophical a question, that I merely touch on its actual bearings on the passage of projectiles to show how the quantity of force is absorbed or expended in relation to the quantity of the gunpowder employed; which, it may be assumed, is a proportion of nearly one-third of the whole, or a quantity independent of that necessary to give velocity to the leaden projectile, to enable it to overcome the still and uniform impeding agent up to the end of its flight. The rapid exit of the bullet from the barrel, with a resisting influence of this weight into the comparatively insignificant one of 15 lbs. to the square inch, will fully explain how it is that a bullet increases in velocity even up to a considerable distance after leaving the muzzle of the gun; and further showing that in all arrangements of truly scientific gunnery, the increasing resistance must be met by a fresh production of explosive fluid over every atom of space in that tube, where it is demonstrable that the resistance is increasing in a geometrical progression as the point of exit is becoming nearer; so that gunnery, unless all the contingencies are provided for, must necessarily remain an imperfect science.

Intimately allied to the displacement of the atmosphere is the amount of friction. Gunnery is now rid of the anomaly of being assisted by friction: the detention of the projectile in the tube by artificial friction, to enable more force to be generated, is one of those absurdities pardonable only in bygone days. Science is best consulted by lessening friction; guns of steel, with interiors as fine as the polish in a mirror, are found to shoot best: a rough road is but so much force uselessly absorbed; the experience of the last few years having proved that a range of 1,800 yards cannot be accomplished except with barrels having surfaces as smooth as possible.

Rifles, no doubt, are now in use in which, by increasing the degree of spiral, friction is more than doubled, perhaps trebled; but such unscientific constructions are but as one error to counteract another. Unscientifically formed projectiles not having in themselves the principles necessary for true flight, have to receive a counteracting agency in the shape of additional spinning, on an axis coincident to the line of flight, to enable them to range a given distance, with, as it will be perceived, an additional amount of expellant agency; but these cannot be included in the category of scientific gunnery.

3rd. Next to absence of friction is the construction of the gun barrel. Already have we shown that the inner surface of a gun barrel requires to be like glass; next to this it is necessary that the metal should be composed of the most unyielding structure. Metals absorb force in proportion to their softness: a barrel constructed of lead gives the worst result of any metal; in truth, as is the increase of tenacity and density in the tube, so is the increase of range in projectiles. The wonderful results displayed by the use of steel guns of all descriptions bear out this assertion to the fullest extent. A yielding gun barrel may be compared to the dragging of a heavily loaded waggon over boggy ground, which rises in a wave before the wheels during its progress.

4th. Next in importance to the inflexibility of the gun barrel is the form of projectile best calculated to displace the atmosphere during its extended flight. Under the head of Rifles this subject will be more fully discussed; but, as thousands of years have stamped the arrow as being in accordance with nature’s laws, it should no doubt be the object of science to approximate the leaden projectile to that form as much as possible, and hence the cylindro-conoidal may be assumed to be the best form of projectile.

That both Jacob’s and Whitworth’s bullets partake of a certain amount of “wabbling” motion after leading the muzzle of the gun is certain, from their length, as well as from the fact that in both the centre of gravity is in the hinder part of the bullet; thus they are both in reality bad in a scientific point of view.

If any merit can be claimed for either, it is on account of the mechanical ingenuity displayed in neutralizing the effects of want of scientific principle. The want of principle, however, is not the only evil, were such guns to come into general use; their manufacture, in the hands of that portion of the gun trade which never estimates consequences, and never studies the theory of the science at all, but manufactures all fire-arms by “rule of thumb,” would prove dangerous in the extreme.

The bursting of barrels in any attempt to project lengthened projectiles is of a very different description to that which ordinarily occurs, on account of the different direction in which the force is applied. In consequence of their greater length, and their increased friction against the sides of the barrel, they are more reluctantly set in motion—i. e., their inertia is with greater difficulty overcome. The result of this is, that in overcoming their inertia the greatest strain is exerted backward, on the breech of the gun; which, if not more firm than usual, is blown out, entering the forehead of the shooter: an accident which would prove fatal not only to the gun, but to the person who used it.

This accident may no doubt be effectually guarded against by strengthening the breech end of the gun as well as the breech itself; but without that precaution it is to be feared that such accidents would be of frequent occurrence.

A considerable error may easily be promulgated, as to the heat necessary to be applied ere gunpowder will explode. A late writer says, it is necessary to raise it to 600 degrees before it is explosive. This is a splitting of hairs, and such a palpable mystification, that it is scarcely worth noticing. But I will explain: if you place upon a plate a few grains of powder, by heating the plate underneath (for instance, on a smith’s fire,) you will see the sulphur giving out a blue flame, it being easily fused. As the plate becomes heated to nearly a red heat, the whole explodes, in consequence of the charcoal and nitre not being hot enough to allow the gases generating the heat to be liberated; but as soon as this does take place the explosion ensues. Now, it is a well known fact, that the smallest particle of matter possessing above 600° of heat, will ignite any quantity of powder it comes in immediate contact with; we will suppose with one portion of charcoal, one of sulphur, and one of nitre (it matters not how small they are: a ten hundredth part of the substance of one of the smallest grains of powder would suffice), and if it has the means of communicating to these small portions 600°, this is sufficient, as their explosion induces also that of the very largest quantity: for it ought to be perfectly understood, that a great explosion is but so many millions of small ones combined, and by their united force effecting the great results we see. The ingredients of powder are ground and intimately mixed together on the bed of the mill to the great extent they are, to the end that, if possible, there shall not be in the composition two grains or portions of one ingredient in immediate contact with each other; but that, when the ignition does take place, each may be present to add its peculiar gas, in order that each affinity may be supplied. Thus becomes evident the necessity of a most extensive incorporation, a blending and equal division of mixture throughout the whole material.

The advantage of unglazed gunpowder is here fully shown; for it presents an inequality, a roughness of surface, over which the flame from the percussion mixture cannot travel without igniting some of the prominent parts, and thus the whole. You may glaze powder and make it so smooth that it would be very difficult indeed to ignite; but except that it enables the powder to resist moisture better, it is otherwise very detrimental, as tending both to prevent ignition and lengthening the period of effecting it.

The flame from the percussion powder is of that intense and vivid description, that if a charge of powder in the breech of a gun is loose, the flame will form a mass of condensed air round itself, and driving the grains of powder before it, prevent the immediate contact of the heat and the particles of powder, until the heat is expended; and thus arises a “miss fire.” If the powder is up only to the nipple, there being a quantity of air in the tube of that nipple, the explosion of the fluid will drive down this air, and condense it between the powder and top of the nipple to such an extent as to cause a certain “miss fire.” It becomes requisite to find a remedy for this, and it can only be done by bringing the powder into the very vicinity of the explosion on the nipple. This can be effected in several ways, but the most perfect is to obtain as direct a communication as possible; a widening of the perforations of the breech, and space to allow the powder free access up the nipple. For this purpose we propose an improved form of nipple. The centre one of the three (here shown in section) is considerably broader and shorter than the others. A cap made broader and not so deep would be an improvement, as bringing the point of ignition nearer the charge, and thus effecting a saving of time; for great and wonderfully quick as is the explosion, it is clear to the senses that it may be quickened. We are not finding fault with the “lightning being too slow,” as Colonel Hawker says; but science means perfection, and the nearer we can come to it the better.

The nipples now in general use have the smaller orifice at the bottom, and, being lined with platina, never foul. Experience has shown that admitting the gunpowder into the nipple “is not advantageous,” especially with large grained powder; by constructing the nipple with the small orifice at the bottom, the largest grain can be used beneficially. As the velocity of the fulminating gas is much greater than “a train” of gunpowder ever can be, quickness is also gained by their adoption. I have used them for many years with great success; nothing but cost deters their general adoption. The passing of the flame through the very small opening in the platina, by this very high impingement, increases its heat to a great extent, ensuring explosion.

The true science of gunnery consists in knowing that a certain force is requisite to effect a certain purpose, or, in other words, to kill at a certain distance; and also how to arrange that force so as to effect the purpose without having any extra force, or any waste of powder, nor yet too little, but with a corresponding result: a sufficiency; neither more nor less. This we have shown is attainable by the mechanical arrangement of granulation; for it is useless to use less, or to use an iota more of fine grain powder, if the size larger will effect the purpose without that iota. Propellant velocity is the grand desideratum in all gunnery; the obtainment of this, to the greatest extent, is the power of killing at the greatest distance: all ranges are dependent on velocity; no extreme range can be obtained without a corresponding speed.

The very finest powder, it will be perceived, is fitted—perfectly fitted, preferable, indeed—to coarser grain for guns of a short length of tube, where a perfect combustion of the whole charge can be obtained without any waste or want; but as such is quite unsuited for longer barrels: I cannot too often repeat it. The column of air is the ruling power. Look what its effects are by Hutton’s calculations, with the very low velocities he obtained! So great as to bring all projectiles he used to a medium velocity, before they were projected beyond a certain distance. Then what must its resistance be where the velocities are trebled? I say trebled, for my powder and the percussion combined have more than trebled the velocities. You must then clearly have a powder of such grain as suits the capacity of your gun. All barrels have a size of grain that will suit them best, and manufacturers of gunpowder will consult their own profit and the convenience of sportsmen, if they assimilate the grain of powder to various sizes; as in shot, to No. 1, No. 2, 3, 4, 5, and so on: eventually this system must be adopted.

This will explain quite clearly how the fact (singular to many) occurs, of short guns excelling their longer competitors, and how frequently a particular maker obtains an immensity of credit for an excellent gun only twenty-two inches: “Beat my Lord So-and-so’s of thirty inches!” and how, “When I cut four inches off my double, she shot better than ever she did.” All these occurrences are perfectly dependent on a knowledge of the generating of the explosive force, and may be reversed at any time by a person possessed of sufficient knowledge of these facts: put in coarse grain into the short gun, and fine into the long, and the facts will be changed considerably, as will be easily seen. A degree of mystery has hitherto existed as to the cause of this discrepancy; but I trust this explanation will clear it up.

Experiment has shown the error of stating that only a certain quantity of powder could be consumed: the proportion stated was considerably below the actual quantity, as the experiments of punching the plates show; for since twelve drachms can be burnt in a three-feet barrel, therefore ten drachms may be consumed in one two feet eight inches, with a given weight to lift. In addition to this, must be placed the fact of improvement, both in the composition and granulation of the powder; which we have no hesitation in stating has been considerable, within only a very few years, all tending to the quickness of generating force. The granulatory system, if acted upon, will give the sportsman or soldier a completely new power in gunnery; for it must be evident, if we have the means of projecting certain bodies with an extreme velocity, say 5,000 feet per second, it becomes a simple calculation to ascertain the quantity of force and length of tube to give to a certain weight. Take, for instance, an ounce ball in a barrel two feet six inches long. Extremely fine grain powder, from its rapidity of expansion, gives to the ball this velocity at fifteen inches from the breech; the remaining fifteen inches contain a column of air highly condensed, which will inevitably reduce this velocity back nearly fifty per cent., or 2,500, and with that velocity the ball leaves the muzzle. Therefore, as we have already said, it must be evident you have here generated a high speed to be as quickly reduced; and it shows clearly that if a different grain of powder would expand from breech to muzzle, increasing the velocity on a granulated scale until it obtained the highest, or 5,000 feet per second, as the ball left the muzzle, you would save here clear 50 per cent. in force, with less recoil, less internal strain on the barrel, and with exactly the same weight of powder; thus showing that you have just a definite quantity of force in a definite quantity of powder.

The true science of gunnery is the knowledge how to best arrange the collateral parts, so that you may obtain the greatest result with the least means. I have also clearly shown that the resistance of the atmosphere is one, and the principal obstruction in the attainment of high velocities; its resistance being regulated entirely by the degree of speed with which it is wanted to be displaced. Thus it is true, as both Robins and Hutton have shown, that only a certain velocity can be obtained beneficially; though the degree is considerably greater then either conceived, as far greater impetus has been obtained, and projected bodies have ranged much beyond their calculations, and that beneficially too. One drawback on the theory of these gentlemen is their calculating the velocities with iron projectiles; for the heavier the material the more powerful the momentum, and consequently the longer retention of their velocity, from not presenting the same space to the resisting medium, the air.

The development of the system of granulation must and does exercise considerable control over the shooting of barrels of every description. I have already explained what has been hitherto considered the curious phenomena of short and long barrels shooting so dissimilarly, and this illustration completely establishes the fact of the expulsive and repulsive forces being controlled by each other: as either preponderates, so is the result. The open-ended barrel projecting balls, and eventually bursting, is a beautiful and interesting elucidation, both of the force of gunpowder and the stubborn nature of the atmospheric fluid. All these facts are valuable, inasmuch as they lay bare circumstances which have never been satisfactorily accounted for, and enable the mind of lowest capacity to understand the cause and effect.

The superiority of one barrel in throwing shot stronger and more evenly distributed, arises, it will be easily seen, from the absence, or existence of, internal friction, when contrasted with the different degrees of expelling force, and the degree of resistance from the atmosphere; it also accounts clearly for the fact of guns shooting stronger on one day than on another, in fine and in rough weather: the weight, the resistance of the air, is the only cause of the variation; for gunpowder cannot drive back a dense atmosphere as quickly as a lighter one. The cause of guns bursting is to be placed to the account of both air and the generation of the explosive fluid so instantaneously; the solid front which air offers to quick compression, throws the force on the barrel, and the sides of the tube give way because they are weaker: this cannot occur so easily with powder of a more gradually expansive force, therefore safety is consulted in its use, in addition to the numerous advantages it otherwise possesses.

Mr. Blaine, in his Encyclopædia of Rural Sports, has the following: “The increase of metal in the detonator, we think, with Colonel Hawker, to be an essential requisite, first, to resist the quicker, and, consequently, more forcible, expansive force applied by the ignition of the powder through the agency of detonation, and tend to lessen the recoil so much more forcibly felt in most detonators. This increased weight of percussion Mr. Greener, however, objects to, and inquires, ‘Whether some of the best flint guns met with, have not been very light?’ To this we answer, that it was the principle on which the explosion of the flint gun was effected that enabled it to be made lighter, and yet to remain equally safe in using; but we also know, that where it was required to add to the rapidity and force of the ignition, it then became necessary to increase the substance of the barrel.”

Experience teaches the writer, and I dare say it would Mr. Blaine, if he were to experiment to the extent I have done, that there is no rapidity in the ignition further than the closing of that point of ignition by the cock, and no “force” beyond what the comparative instantaneous ignition of the gunpowder in the nipple creates. This is quite sufficient to prevent the further penetration of the percussion flame; and the only increase, to quote his own words, “to resist the quicker, and, consequently, more expansive, force applied by the ignition of the powder through the agency of detonation,” arises from an improvement (as it is termed) in the granulation of the powder, which alone creates the increased expansive force. This will be clearly understood by any one reading this work from the beginning; the only difference between the flint and percussion systems is the stopping of the orifice of ignition in one, and allowing it to escape in the other; for the flame has to travel to windward (to use a nautical expression) in the flint; the other has its own accumulating power to force ignition through the body of the powder. This alone constitutes the difference. The necessity for an increase of metal at the breech of a barrel does not arise from any peculiarity in the mode of communicating the fire, but in the increased inflammability of the powder alone. The extreme smallness of grain has effected this more than the use of fulminating flame; and the continuous cry for fine powder, to get better up the nipples, has produced an alteration which is placed wrongfully to the credit of the percussion.

Again, he says, “Mr. Greener, however, would have us acquire this increase of power of resistance, not by quantity of material, but by increased tenacity and elasticity in the metal the gun is formed of, and we agree that it would be a great improvement if it could be brought about. But what is our prospect of it? Is it not the general complaint that gun metal is not by any means what it was? We have shown that it is not; and, therefore, we do not think, as Mr. Greener asserts, that any recommendation of increased weight of metal to the percussion barrel beyond that of the flint gun “is founded on ignorance;” but, on the contrary, that the very reason Mr. Greener gives to prove it, is that which we think affords evidence of its perfect rationality, the explosive force created.” The answer given above applies to this also: save on the score of lessening recoil, superior quality is preferable, to quantity.

The shooting powers of gun barrels are dependent on two circumstances—goodness of metal, and a proper shape of exterior: it cannot be too often repeated, that a gun barrel is a spring, to all intents and purposes; if you add metal, you add stubbornness, and destroy that expansibility, without the existence of which the barrel is, comparatively speaking, useless. Heavy, ponderous barrels do not propel a charge of shot with either that smartness or degree of closeness that a barrel more scientifically constructed does; you have less recoil certainly, but the addition of half an inch of more metal behind the butt of the breech would do this more effectually, and save you carrying an additional weight. The gradual ignition of powder obviates the necessity of a great thickness of metal in the sides of the barrels; but if it is determined to persevere in the use of peculiarly fine grained powder, you would certainly be justified, nay, required, to have more and better metal than at present, for the electrical nature of the explosion will throw upon the tube that force which would be more judiciously employed in giving impetus to the charge of projectiles.

I have found that expansion will increase the shooting powers of a barrel; but then it must not be the expansion of an unelastic piece of metal, but of metal whose elasticity rebounds with a force equal to that with which it expands; for whatever else you may obtain by creating friction, by boring the breech end of the barrel wider you obtain a greater expansion, as it no doubt has that tendency. We find it an invariable fact, that when barrels are very heavy, compared with their size of bore (if a cylinder), they shoot weak. Also, when barrels are made of irons of different temperatures, where one is placed to prevent the expansion or springing nature of the other, they are never found to shoot well. As a proof of this fact, let any one take the best barrel he ever shot with, and encase it with lead very tight; fire it at a dozen sheets of paper, and see if the effect be equal to what it was when the barrel was unencumbered. On the contrary, it will be found to have shot very weak, though close. Let him then examine the lead; and, if any moderate substance, he will find that the explosion has enlarged it considerably. This experiment I have tried repeatedly, and can vouch for its truth.

The proof of barrels is another fact corroborating the truth of our assertion. What else can occasion the bulging, but the expansion? Where the barrels are possessed of soft and hard portions (which is the result of different tempers of different metals), one expands further than the other, and then, of course, the soft part receives no assistance from the hard, and it does not return to its original state.

Put on a barrel, from the breech end to the muzzle, a number of rings of lead; be sure you have them tight, and not further apart than three or four inches; fire that barrel with a usual charge, and if it be a correct taper for shooting, it will have expanded the whole of the rings an equal distance.

From the observations already made, the reader will perceive that the shooting of all barrels depends on a certain degree of friction. The degree of friction necessary, varies according to the nature and substance of the metal. Those metals that require least shoot best. The object of the friction is to create a greater force, by detaining the charge longer in the barrel. If, then, there should not be an extra quantity of powder to consume, the friction would be a decided evil.

This may be understood by rifle practice, in which we find that a short barrel of eighteen inches, with a certain charge, will throw a ball as straight, and quite as strong, or stronger, than a barrel of three feet, loaded with a similar charge. I account for this fact thus: the barrel of eighteen inches will burn all the powder put into it; the long one can do no more. As soon as the ball has left the short barrel, it meets with no impediment but the air. By the time the ball in the longer one has travelled eighteen inches the powder is all consumed; the volume of air in the remaining eighteen inches acts as a destroyer of the force given to it, and it naturally drops its ball short of the other. Increase the charge of powder to as much as the long one can burn, and then it will throw its shot to nearly twice the distance of the other.

An addition of powder beyond the quantity the barrel can consume is disadvantageous; the reverse will be found equally so. Thus it is with fowling-pieces. The quantity of powder that a gun would burn in the shape of a cylinder, would be too little, when, by altering that shape, you increase the friction. The quantity must, therefore, be increased, or this friction will diminish the force of the shot. It is on this that the mistaken supposition is founded, that short barrels will shoot as far as long ones. It is true that with a small charge, or very fine powder, the short barrel will kill at the distance of thirty yards, as well as the long one; but put in the long one as much powder as it can consume, then try the two at twice the distance, and you will find out the mistake under which you have been labouring.

It is on the nature of the metal that the goodness of the shooting principally depends. That barrel which is possessed of the greatest degree of elasticity and tenacity, will throw its shot strongest and closest with the least artificial friction. It is on the knowledge of the qualities and temperatures of the various irons, and on practice in the art of shooting, that a man’s ability in making guns shoot with precision must rest. All plans are merely methods by which an unscientific maker has most frequently succeeded. It would be no difficult task to produce a hundred barrels which will shoot nearly alike; yet every barrel shall be different in its bore.

The length of friction depends entirely on the length of the barrel. Long barrels require more than short, though the latter require it in a greater degree. A mode of creating friction, much practised by those who are ignorant of the true method, is to bore the barrels as rough and as full of rings as possible. These rings are often taken for flaws; though that may be ascertained by noticing whether or not they have the same inclination as the twist, and whether or not they are at the jointing of a spiral. If they be not, the chance is that the barrel is ring-bored, as it is termed. This roughness, however, answers the same as friction by relief; but barrels thus roughened are very liable to lead, and become foul. While the well-bored barrel will fire forty shots as well as twenty, these cannot be fired more than twenty times with safety and effect.

Each of the barrels in the table below, if 3-16ths thick at the breech, is equal to the pressure stated. The resistance of a charge of shot of one ounce we find to be more than before stated; and the additional increase of explosive force obtained at the moment of ignition, requires the amount to be much greater in computation, therefore, we may safely take a pressure of 1,700 pounds to the inch of tube. The reader will perceive, on reference to the following table, that with the tube filled with powder for an inch in length, which is a small charge, the explosive force will be equal to 40,000 pounds, or nearly 1,700 pounds to the inch.

If the charge he increased to one ounce and a half, the length it occupies, and the lateral pressure by the jamming, will create an additional pressure in proportion, or near 2,550 pounds, as under:—

A charge of shot two ounces weight will be greater in pressure than barrels of these dimensions are equal to restrain, and, consequently, no barrels should be charged to this extent at any time; but inferior barrels, as a matter of certainty, are sure to give way if so loaded.