« السابقةمتابعة »
ingenuity, depended upon iron alone. The Ordnance Select Committee •were challenged to bring forward the best gun their artillery science, aided by all the resources of the Boyal arsenals and the public purse, was able to provide. The science brought to bear by the Ordnance Select Committee, after exhausting itself in repeated efforts to cover its repeated defeats (efforts that were fruitless for reasons that will be explained), was at length compelled to confess itself vanquished. But Ordnance had other resources which it hoped to have dispensed with, and upon which in its disappointment it was glad to fall back: it said to the Committee of Defence, "If you will obligingly set up your armour-targets within a shortened range (say, for instance, a Bobin Hood bowshot of 200 yards), you shall see what the brute force of the old smoothbore will do. True it is that cast iron will be brought to attack -wrought iron—that a rounded missile will have to punch its way through a flat and possibly at times inclined armour-plate—science, which proved but a broken reed in our hands, must be abandoned; but with a gun big enough, a shot heavy enough, a charge of powder large enough, and a range short enough, the smooth-bore shall smash your target." Of course it would; and so would a battering-ram like those Titus used to break the gates of Jerusalem. If therefore the old smooth-bore had failed the Ordnance Committee, like the service rifled gun, they might have fallen back on the older battering-ram.
Looking at it from a scientific point of view, this retrogression was very humiliating, and it caused the country serious anxiety to hear Her Majesty's Ministers state in Parliament, as they did in the last session, on the authority, of course, of their official scientific advisers, that the Navy of England, after all the vast expenditure that had been lavished upon it, was at last obliged to be armed with the old smooth-bores to meet the iron-clad navies of her possible enemies. This was indeed proclaiming England's weakness to other nations who were more scientifically, informed and better armed than she.
In further explanation of what was the actual condition in which this allimportant question stood no later than May last, I will quote the statement of Sir William Armstrong, who, at a meeting of the United Service Institution, May 20,1862, expressed himself in these words:—" It certainly may be said that shells are of no avail against iron-plated ships; but, on the other hand, I may say that neither 68-pounders nor 110-pounder guns with solid round shot are effective against such iron vessels. The fact is, what we want is a gun, in addition to our 110-pounder rifled gun, especially adapted for breaking through iron plates. That is what we are in want of now." This statement made in 1862 was very startling to all of us, who knew that long ago France armed her 'Gloires' and 'Normandies' with rifled 90-pounders said to be efficient against iron plates. Such being the state of the question a few months back, we may proceed to consider, first, the reason why the artillery hitherto employed in the service, including rifled guns and smooth-bores, has always failed to make any impression on the plated defences at ordinary fighting-range; and secondly, by what means artillery science has lately reconquered its lost ground. Sir William Armstrong put the case very plainly when he said that shells were in fact of no avail against plated ships, and that the solid shot of the 110-pounder rifled gun was not effective against such, iron vessels. But late experiments at Shoeburyness, in which the ' Warrior' target was pierced and shattered at 600 yards, have proved that the case as put by Sir William Armstrong was based on his experience of shells that were not made of the proper form, nor of the proper material, and on his experience of rifled guns that were unable to propel their projectiles with the requisite velocity.
Three conditions may be laid down as necessary to enable artillery to attack successfully armour-plate defences: 1st, the projectile must be of the proper form; 2nd, of the proper material; and 3rd, be propelled from a gun able to give it the necessary velocity. The artillery of the Ordnance Select Committee failed because they utterly neglected the first two conditions, and had recourse to the brute force of the smooth-bore for the third. The expression accepted as representing the penetrating power of shot was "velocity squared, multiplied by weight;" but the form of tho shot and the material were conditions altogether omitted from the expression ; and the importance of the omission will be obvious at once if we take an analogous case, say that of a punching-machine employed to perforate wrought-iron plates. What would be the result if the punch itself, which is made of suitable shape and material, were removed, and a round-headed poker, of brittle cast iron or soft wrought iron, were substituted in its place? The great importance of sufficient velocity is conceded—it is a sint-qud-non condition; but has there not been great misconception in supposing that the old smooth-bore gives a greater initial velocity than the rifled gun? The results obtained will show how this is. The average initial velocity of the 68-pounder is, in round numbers, 1600 feet per second with a charge of powder one-fourth the weight of the shot, the length of the shot being of course one calibre. Sir "William Armstrong stated that with a charge of powder one-fourth the weight of the shot, he obtained with his rifled gun an initial velocity of 1740 feet per second: he did not state the length of his projectile. Mr. Whitworth, with a projectile one and a half calibre long, obtains an initial velocity of 1900 feet per second; and with a projectile one calibro long, like that of the smooth-bore, an initial velocity of 2200 feet per second, being greater than that of the smoothbore in the proportion of 22 to 16. The reason why, under nearly similar conditions as to charge and length of projcctile,the rifled gun had an initial velocity so greatly superior to that of the smooth must be ascribed to the action of tho first condition I ventured to lay down as necessary. The rifled projectile, as compared with the spherical, has a form which is better adapted for flight, and fits more accurately the bore of the gun, so that the gases of explosion exert a greater pressure upon it while propelling it through the barrel. In practice the initial velocity of the rifled projectile is lower than that of the smooth-bore, because with the rifled gun the charge of powder used is much less, while the projectile is much longer and heavier, and has a greater via inertia to be overcome at starting than that of the smooth-bore. If very large charges be used with the rifled guns, and long projectiles, with the view of obtaining increased velocity, the strain becomes too great for the guns to bear; but if rifled guns are fired with charges so low that they are not made to perform half the work they ought to do, then, though the defects of weak construction may not be made patent by the gun being destroyed, they are very plainly manifested by the weak results of their projectiles fired against armour-plates. It is proved by well-known results that the constructors of the 110-ponnder rifled gun, now adopted in the service, do not dare to make the gun perform its full work; but, on the contrary, they find themselves forced gradually to reduce their charges, until they are well beaten by tho old smooth-bore they undertook to supersede. The only conclusion that can be drawn from this fact is, that the gun is weak in construction, and the projectile used with it is defective in principle.
The power of the smooth-bore, with its large windage, to fire large charges, and thereby obtain great velocities, has procured it many advocates; but Mr. Whitworth'8 experiments have shown that if length of projectile be given up, which may be looked upon as the price to be paid for increased Telocity, he can get an initial velocity much greater than that of the smooth-bore. But is the result worth the prioe paid? Not rf a more efficient compromise can be obtained. I use the word " compromise" advisedly, because I think that every one who has had experience in artillery practice will agree with me that the best results are only to be obtained by means of the best compromise. You oannot havo long projectiles and very high velocities without burning too much powder and taking too much out of your gun, or else making it an unwieldy monster.
■ The problem we have placed before us now is, How can artillery be best adapted for attacking armour-defences? The advocates of the smooth-bore are satisfied with one condition—high velocity. Mr. Whitworth objects, and says, f If velocity were all that is needed, I can get more than you do in the proportion of 22 to 16; but to sacrifice all to velocity is a bad compromise to effect a solution of the penetration-problem. You set down velocity as greatest possible, form of projectile of no account, material of no account, and after all can do nothing at an ordinary fighting-range while you wrongly take it as proved that 'shells are of no avail' against iron-plated ships. It would be a far better compromise to bo satisfied with a lower velocity, getting however all you can at a fair price, and combining therewith conditions one and two— proper form and proper material for the projectile." Let us now compare the actual results obtained in the way of penetration by the Armstrong 110pounder (tho proposed naval gun), the old 68-pounder smooth-bore, and the two naval Whitworth guns lately fired at Shoeburyness.
- Tho first two results* will lead every one to the same conclusion that it is to be presumed they led the Ordnance Committeo, viz. that tho Armstrong rifled gun is a worse compromise than the old gun it was intended to supersede. The reason may be inferred from the facts to bo, that besides neglecting conditions one and two, form and material of projectilo, it is very much behind in respect of condition three, velocity; this is to be attributed to the weak construction of the gun, which cannot fire with safety efficient charges of powder, and to the use of tbo lead-coated projectiles. Taking all the results, they show themselves to bo indisputably in favour of tho Whitworth;'—> the old 68-pounder coming second, and the Armstrong last. Let us next examine how they stand in regard to velocity, as shown in the following 'j.able, which, liko the one given above, is compiled from official sources.
* These results were subsequently much surpassed. The Whitworth 70-pounder penetrated 4£-inch plate and backing with shell at 600 yards range, and the Whitworth 120pounder fired its shot and shell through 5-inch plato and 18 inches of teak-backing and i-inoh iron-plate skin at 800 Tarda' range.
With regard to initial velocity, therefore, the order of the guns may he taken to ho, with the charges used—1st, 68-pounder; 2nd, Whitworth; 3rd, Armstrong. It is worthy of notice, however, that the velocity of the Whitworth 120-pounder after traversing 600 yards (a good fighting-range) was found actually to he 1260 feet, whereas the initial velocity of the Armstrong is only 1210 feet.
The total results in respect of penetration proving themselves to he So decidedly in favour of Whitworth, who combines with condition three, viz. sufficient velocity, conditions one and two, proper form and material of projectile, it follows that his must be the best compromise. The slight inferiority in initial velocity of his rifled gun, as compared with the smooth-bore, is more than compensated for by employing a projectile of proper form and material, as is shown by tho penetration being through-and-through both 5-inch plate and backing in the case of the Whitworth, while it is barely half-through the armour-plate in the case of the smooth-bore, and not halfthrough in the case of tho Armstrong gun.
The form of projectile employed by Mr. Whitworth for penetrating armourplates is like the one now beforo the Section. It has a flattened front, the centre being slightly rounded; the middle part of tho projectile is rifled hexagonally, like the bore of the gun; the front and rear of the projectile are made of the requisite taper to allow the air displaced in front to close in readily behind— a form which gives a great increase of velocity as compared with the form parallel throughout, as I endeavoured to explain to this Section in a paper I had the honour of reading at its meeting last year.
The material of which the projectile is composed is what is termed homogeneous metal, combining the toughness of copper with the hardness of steel: it is made hard enough to penetrate the wrought-iron plate, but not so hard as to be brittle and break up when tho projectile strikes against its surface. The advantage of tho fiat front as compared with a pointed front is apparent, when it is considered that when tho flat front strikes a plate, the whole resistance it meets with is that offered by the area of the plate covered by the flat front in a direction in lino with the axis of the impinging projectile: it consequently punches out a clean hole, with a sudden impact. In the case of a pointed shot, as soon as the point begins to penetrate, tho inclined sides begin to push aside the particles of the plate in a lateral direction, and an accumulating lateral resistance is offered by every part of the plate whose particles are disturbed; tho passage of the shot is thereby gradually retarded, if not altogether arrested. It has been thought that the flat-fronted projectile will glance from the surface of an inclined plate like & round projectile: this is not found to be the case, as is proved by the plate now shown to the Section, which was completely penetrated by a flat-fronted' projectile when inclined at an angle of 37° to the perpendicular.
The Whitworth penetration-shell, whose destructive power was shown by its penetrating and shattering the 'Warrior' target at Shoeburyness, has thd same form outwardly, and is made of the same material (homogeneous metal) as the flat-fronted solid projectile which has already been described. A cavity is formed in tho projectile of the size required to contain tho bursting charge of ordinary powder. The rear is closed entirely by a screwed plate or cap. The uncertain complications of percussion-fuses, and also the simpler time-fuses, are wholly dispensed with. No fuse or detonating substance of any kind is used. On firing his shell through iron plates, Mr. Whitworth found that by the force of impact and friction sufficient heat was generated to fire the bursting charge without any fuse at all. In practice tho action upon the powder was found to be even too rapid. To retard its action for the time necessary to enable the shell to effect a complete penetration and then to burst, Mr. Whitworth interposes between the metal of his shell and his bursting powder-charge a substance that is a non-conductor of heat: by preference he encloses the powder in a flannel case, and finds that by simply diminishing or increasing the thickness of his flannel he can burst "his shell in the armour-plate or in the timber-backing, or after it has passed through both. Tho fragments of the shell now before the Section are those of one which was fired through this armour-plate, and which burst and shattered this backing of timber, 9 inches thick, placed behind the plate. There is one point in connexion with the Shoeburyness trials which should be specially noticed, and it is this, that all the previous experiments against the ' Warrior' target had been confined to the 6hort range of 200 yards; at longer distances the smashing, monster smooth-bores cannot be made to hit the mark; whereas Mr. Whitworth has proved that at a good fighting-range of 600 yards he can hit his mark to a few inches, and can at that distance—and there is good reason to believe at twice that distance—send his shells through the 'Warrior's ' sides. That 600 yards may be fairly called a good fighting-range will be admitted when we remember that the 'Agamemnon,' at Sebastopol, fought all the guns of Fort Constantino at a range of 500 yards; and the 'Albion' signalled, "Well done, Agamemnon!—where you lead, we will follow." With respect to the 120-pounder gun itself, it should be explained that it was made at Woolwich, under the able superintendence of Mr. Anderson, at Mr. Whitworth's own request, and according to drawings originally supplied by him. It has the same bore as the Armstrong 110-pounder, stated by Sir William not to be effective against iron-plated ships. It is a built-up gun, and its hoops are made of coiled iron, welded; but that method of manufacture was adopted by Mr. Whitworth in the first built-up gun that he made, and was well known in this country many years before rifled guns were introduced into the service.
Mr. WThitworth has himself employed by preference the homogeneous metal, which he has found to answer perfectly for small arms and field guns, as well as for the penetration-shells which have been described. Practical improvements have been made in the process of forging and annealing the metal, which now enable it to be worked in masses of any required size, whose quality may be henceforth depended upon with certainty.
Whitworth heavy guns are now being made with both interior tubes and outer of homogeneous metal of the improved manufacture, so that the guns will be constructed throughout of one uniform metal without any welding at all. Experience justifies the expectation that they will be free from the objections which it is well known are inherent in all welded guns, and be fully able to resist the severe and searching strain which is sure, sooner or later, to disable a gun built up of forged coiled tubes, if it be called upon to do its full work by discharging heavy rifled projectiles at the most efficient velocities.