THE MONCRIEFF BATTERY. T HOSE who had never heard anything of
the Moncrieff Battery until within the last few months, and who have only half considered the broad questions which this solution of one side of the fortification problem opens out, are probably wondering why so much fuss is being made about a gun-carriage.
Those who have been interested in the invention during the ten years of its incubation, have for their parts been inclined rather to wonder why a fuss has not been made about it before.
Perhaps the British public will come to wonder as these last before the invention is done with ;—and then not to wonder, when they remember the difficulties which beset the introduc- tion of a new invention and the obstructions which oppose it. Without pausing now to examine, on the one hand, the causes which interfere with the ready and immediate acceptance of every new invention which comes forward, and which would naturally operate with greater force in proportion as the invention is original ; and without, on the other hand, reck- lessly assigning the delay to official obtuseness, we may observe that Captain Moncrieff's invention is sufficiently im- portant to have merited recognition some time ago, and fully to warrant all that is being said about it now. For it is to be noticed at the outset that the invention is not by any means comprised in the expression "a mere gun-carriage." That is exactly what the Moncrieff battery is not. It is a battery—a system—a fortification in itself. The carriage is but the material application of the system. To make this clear, we will endeavour in as few words as possible to explain what the invention is designed to effect. The simplest and most primitive form of defence is, we need hardly say, a parapet of earth, or sand, or natural materials. Given such a parapet, the question straightway arises, how shall it be applied to the protection of men and guns ? In the case of riflemen there is no difficulty. The soldier remains behind the parapet until he has loaded his rifle and is ready to fire, when he rises up, discharges his piece, exposing him- self for a moment, and at once retreating behind the parapet again. This is simple enough, and this is the natural order of defence. The parapet is a fixed shield, from behind which the defender appears only momentarily to strike his blow, exposing himself as little as possible. In the case of a gun, however, the problem is less easy of solution. It has not hitherto been found practicable to raise and lower guns weighing many hundredweights or tons as handily and readily as rifles. So the guns have been fixed in position to fire either through the parapet or over it. The first of these systems gives us the Embrasure ; the second gives us the Barbette battery,—each with its objections and its advantages. The embrasure obviously constitutes in itself an unprotected point. It is a breach in the continuity of defence, affording a good mark for the enemy's fire, and furnishing a ready means of entrance for shot and shell. But this is not all. The embrasure necessarily restricts greatly the lateral range of the guns, which can only deliver their fire within the angle defined by the splay of its sides. Again, an embrasure is easily destroyed. The breach already commenced is greatly widened by a few well-directed hostile projectiles ; even the concussive effects of its own gun, and the gradual deterioration due to rain and weather, in time accomplish what the enemy may fail to achieve. To meet this last class of objections, and in view of the increasing range, accuracy, and power of rifled ordnance, it has become necessary of late years to supplement the weakness of the primitive earth opening, or the modified weakness of the revetted embrasure, with a shield of some sort.
And in an iron age, iron shields naturally presented themselves as a most efficient means of defence. Thus the Gibraltar and Millwall Shields, for example, were designed to close the embrasure, leaving only an opening for the gun to fire through. This, the latest and best form of embrasure, remains, however, an embrasure still—an iron instead of an earthern one. But until the introduction of Captain Mon- crieff's system this iron embrasure promised to present the most familiar type of defence. The Barbette system consists in raising the gun permanently above the parapet over which it is to fire. By this arrange- ment the characteristic disadvantages of the embrasure ara got rid of. The guns have free lateral play, the parapet is- unbroken, and the infantry men behind it are securely protected. But these advantages are obtained at the ex- pense of the gun and the men who have to serve it, for the guns and gunners are scarcely protected at all. Raised above the parapet, they furnish fair marks for the enemy. And so accurate is the fire of modern ordnance and small arms, that practical men have long since deemed that the days of barbette batteries are past. If any one desires the enlighten- ment of actual experience on this point, he has but to read Colonel Von Scheliha's Treatise on Coast Defence, where he will find among the deductions from the experience acquired in the American war, one to the effect that barbette batteries. are nowadays not tenable. And this deduction he will find expressed over and over again. Thus, we were left with a choice between two evils : on the one hand, the fettered fire of the embrasure, with its imper- fect protection ; on the other, the almost total absence of pro- tection afforded by the barbette system. A third plan, it is true, has found some favour, a plan which combines many of the advantages of both the barbette and embrasure,—the plan, that is, of revolving cupolas or turrets. By this system free lateral range is obtained and excellent protection. But the cupola has its disadvantages too, the chief one being its enormous cost. Added to this, it is not absolutely invulnerable; the porthole, however small, is an embrasure, after all, and thus presents a point, however limited, of attack ; and, finally, it is not a pleasant thing to have to fight your gun in a close box, the mechanism of which may get out of order, and either cripple or helplessly expose you.
At this point Captain Moncrieff steps in and strikes through the mass of difficulties by treating his gun exactly as if it were a rifle. He goes back to the primitive system of defence, and asks for a simple earth parapet only, by means of which he promises to afford us an almost perfect protection. And this is how he accomplishes his object. He mounts his gun on a small carriage, which rests upon a pair of curved iron elevators or rockers. Under the fore part of these rockers he places a counterweight, slightly in excess of the weight of the gun. We will for the moment suppose the gun to be loaded and ready to fire. It is now en barbette, the counterweight being at the bottom of the system, the gun at the top and looking over the parapet. The weight being heavier than the gun, the system remains in this position until the gun is fired, when the force of recoil disturbs the equilibrium, recoils the gun backwards upon its elevators, and raises the counterweight. By this act of recoil the gun becomes lowered behind the parapet, and being here held by a simple mechanical contrivance, it is ready for loading, gun, carriage, counterweight, and elevators being completely hidden from the enemy. It is the rifle over again. Up to fire ; down to load. When the loading is accomplished the catch is released, the superior weight of the counterweight brings it down and raises the gun into the firing position, whence, after delivering its fire, it again retreats. It will perhaps be possible for our readers to gather from this rough general description a fair notion of the main features of the invention. For fuller details they must turn to other sources.
Next to the bold but simple conception of treating a huge gun as though it were a rifle, what is most to be admired is the ingenious way in which this conception has been carried out. The end is accomplished without having resort to any new force or elaborate mechanical contrivance. All that is done is to utilize a force which had hitherto been not only useless, but absolutely hurtful. The force of recoil has always been a great bugbear with artillerists. It has been a destruc- tive, troublesome force, to be got rid of somehow,—to be checked by breaks, and buffers, and friction surfaces, to be absorbed by great weight in the gun, by great strength in the carriage, and by stout pivots, and racers, and platforms. But always it has been an agent potent for evil, not for good,—one of which artillerymen would gladly be quit. This force Captain Moncrieff has converted into a useful ally, and coaxed into doing invaluable service. He makes it the muscle of his system. It carries down the gun after firing ; and, stored up in the counterweight, it raises the gun after loading. No expression better describes what Captain Moncrieff has done than one which he himself used in a lecture some years ago at the Royal United Service Institution. He said that he " set one elephant to tame another." There is something exceedingly beautiful and philosophical in this contrivance ; and none the less credit is due to Captain Moncrieff, because it seems, now that it has been accomplished, almost self- evident. Inventors out of work must, one would think, be tearing their hair at the thought of how great and obvious an opportunity they have let slip. But it has been done at last, and that with so perfect and careful an adjustment of constructive detail, that the most complete and remarkable success has attended the first trials. Speaking broadly, we may say, that in the course of the trials which have this summer and autumn been made with a 61-ton gun, mounted in this way, and giving, with elevators, counterweight, and carriage, a total moving mass of 22 tons, no hitch worth mentioning has occurred. The working of the system has proved in all respects admirably satisfactory, far more so than its most sanguine supporters could have expected. The gun has shot accurately ; the carriage has worked smoothly ; it has proved rapid in operation and sur- prisingly easy to work, so easy, indeed, that on one occasion a detachment of three men worked the gun and fired five rounds at a moving object with fair rapidity. With larger detachments (ten men and a non-commissioned officer) and a little more experience, a rate of fire of one shot in a minute and three seconds has been attained. The carriage has been covered with sand and dirt, and has still worked satisfactorily. The reflecting sight, by means of which the gun can be laid without exposing a single man, has answered well. And although the trials are not yet completed, but little remains to be done, if anything, to establish the invention as an accomplished success.
Even to glance at the many applications of the system and its remarkable advantages would furnish matter for a separate article. But we must notice as briefly as possible the main advantages which will accrue from its adoption. In the first place, the protection which it affords seems all that is to be desired, and very much more than until lately appeared to be attainable. Not a man need be ex- posed, and the gun itself only appears above the parapet for the few moments necessary to enable it to be laid and deliver its fire. The parapet may be as thick as is thought necessary, and that most efficient of all materials, earth, can be employed. A thick earth parapet may, indeed, be made practically indestructible. We had tolerable evidence of this in the case of the parapets which formed the landward defences of Sebastopol. The gun derives also incidental protection, from the fact that as it only appears for a moment and leaves no trace of its whereabouts, nothing remains for an enemy to fire at. But Captain Moncrieff proposes to use, on occasion, no parapet at all. He proposes to place his guns in " gun pits," thus making the natural surface of the ground his parapet. In these cases there is absolutely nothing for an enemy to destroy. When a parapet is used it becomes possi- ble to mount the guns on a travelling carriage on rails, and so to run it along from one part of the work to another. And the uncertain, momentary appearance of a gun over a parapet would be scarcely less embarrassing to an enemy than its sudden and unexpected appearance out of the ground where no defences are known to exist. The absence of any hori- zontal strain due to recoil removes the necessity for expensive solid foundations for the platform, in addition to rendering practicable that application of a carriage on rails of which we have spoken. In point of economy the system presents im- mense advantages ; costly iron shields or still costlier cupolas will in certain positions be no longer needed. And, owing to the command and free lateral range of guns mounted in this way, one "Moncrieff " gun would be equal to at least three firing through embrasures. When gun pits are used it would be unnecessary to make them before the actual occasion arose, and thus the plan of a great part of our fortifications would be kept secret, and all the expenses of repair avoided. All that would be necessary would be to decide where guns should be placed in case of need, and to keep a supply of these car- riages ready against an emergency.
The invention promises to effect a considerable and econo- mical revolution in the science of defence—economical, whether we consider it in regard to the nature of the parapet, the number of guns required, the cost of the defensive and mechanical appliances, and the saving of life ; while it must add greatly to the efficiency of the defence, and give it an advantage over the attack -which to a defensive power like England can hardly be exaggerated.
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