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was the passion to be gratified. We go to hear the human voice do what it never did before, for the same reason that we go to see human legs and arms do what they never did before. We admire him who runs highest upon the musical scale, upon precisely the same principle that we applaud the Indian jugglers twirling their balls, or Mr. Ireland leaping over a pole thirty feet high.
FROM THE EDINBURGH PHILOSOPHICAL JOURNAL.
Observations on Sir Robert Sepping's Plan for the Circular Sterns of
Ships of War. By GEORGE HARVEY, Esq. Member of the London Astronomical Society.
Few naval architects, of any age or country, have been more singularly fortunate in the original conception of important and useful designs, than Sir Robert SEPPINGS; and the great success which has attended the practical application of his plans, has commanded a respect for his name, which, there can be but little doubt, will increase in proportion as their excellence and utility shall be better comprehended and known.
But there is one of the designs lately brought forward by this distinguished individual, which has been questioned with a keenness and severity of a very uncommon kind; and, it may not be unfairly added, has been opposed by prejudices of no ordinary stamp. From the infancy of naval architecture, up to the present moment, no branch of it has undergone such varied discussion-been canvassed and examined with so much interest and zeal,--and produced so many singular, and, in many instances, unmeaning comments, and contrary opinions, as the change which this eminent surveyor is desirous of introducing into our ships of war, by converting the square into a circular stern.
It is one of the rare merits of Sir Robert Seppings, that all his plans are of a useful and practical kind; that being founded originally on the best experience, and undergoing, in every instance of their application, a strict and rigorous inquiry, they have in most cases been productive of great immediate benefit to the public, and consequently entitle their author to the highest honours which a great and powerful nation can bestow.
It is, however, sometimes the fate of the most important and beneficial improvements, on their first introduction, to be questioned with unusual harshness and severity; and the spirit of this opposition is, in general, in proportion to the degree in which the proposed innovation happens to depart from long established usage. The whole history of science is filled with lamentable proofs of this frailty of our nature; and we need not even go beyond the borders of the present century, to meet with many, very many, proofs of the baneful influence of those active and unfortunate prejudices. The Safety-Lamp, the most inestimable of the discoveries of the illustrious Davy, was destined, on its first introduction, to meet with an opposition of this kind; but time, which always renders more conspicuous the triumphs of genius, has placed it on the firmest and best foundation, and shown that it is a rich in blessings to mankind." That consequences
equally satisfactory must ultimately result from the plan of the Circular Sterns, there can be but little doubt. The opposition which it has met with, has only served to quicken inquiry; and now that its ingenious inventor has brought the subject before the public, * in a shape which will enable every one interested in the inquiry to examine it for himself, the merits of the question must be fairly and impartially considered ; and those objections which imperfect practical information may have urged, or that opposition which seems to have owed its origin to certain preconceived notions of beauty of external form, will unquestionably vanish before the conclusions drawn from a sound and enlarged experience.
Circular sterns, when contrasted with those of a square form, may be contemplated under two points of view. In the first place, We may inquire into the strength peculiar to each form, considered as a system of mechanical forces; and, secondly, The means which each affords for carrying into effect those objects for which a ship of war was primarily constructed, namely, attack and defence.
In the mechanical construction of a ship, every part of its structure ought to possess a proper degree of strength, no one part possessing, if such an expression may be made use of, more strength than is absolutely necessary, nor any part less strength than the nature and office of that particular part is destined to maintain. And it is in the due adjustment of the several parts which constitute the frame of a ship, considered as a system of mechanical forces, that the science and judgment of the naval architect find so wide a field for the exercise of his powers:
Where a general similarity of construction prevails, it is impossible to derive any information from comparison. No advantage, for exam. ple, could be derived from comparing the square stern of one vessel with the square stern of another, supposing equal skill to have been employed in their construction. But we may arrive at some satisfactory information, by contrasting the strength and firmness of structures of different forms,—the strength of the stern of a ship, for example, with that of the stem. It may indeed be urged, in opposition to such a comparison, that, independent of the dissimilarity of form which at present actually exists between the stem and the stern, the duties which they are destined respectively to perform are so very opposite to each other, that nothing satisfactory could be hoped for from the comparison. The dissimilarity of form, and the difference in the respective offices of the parts just alluded to, will be immediately admitted. But if it should appear on examination, and by an appeal to authentic documents, that a weakness in the stern is much more common than in the bow, then will both these objections be fairly disposed of, and a superiority in the formation of the bow over that of the stern will be the necessary consequence.
To enable us to institute this comparison in the most satisfactory and perfect manner, Sir Robert Seppings, in the first Appendix to his able Letter, has furnished above 120 examples of ships of different classes, the sterns of which have been made the subject of frequent and strong complaint by their respective commanders. To increase the
Sir Robert Seppings has lately published a Letter on the subject of Circular Sterns, addressed to Lord Melville.
value and importance of these documents, it is worthy of observation, that they have not been collected from any very limited portion of time, or when any particular feeling in favour of a change of form might have existed in the navy, but during a period of nearly a quarter of a century, and through the trying services of a long and active war, and when the attention of every naval officer was necessarily directed to the actual state of the ship he commanded. These evidences, also, it may be farther observed, in favour of the weakness of the square stern, have been selected from a multitude of other official reports of the same kind, drawn up by able and experienced officers, placed in circumstances of a very varied and difficult nature, and with no other object in view than the good of that service to which they have so honourably devoted their lives.
To group together facts, it has been observed, which have some important qualities common to them all, is the main scope and business of philosophy. Now, the examples contained in the Appendix alluded to (of which those in the preceding Note may be regarded as a specimen), affords a most striking instance of the value and importance of this remark. Every document in the table bears a decided testimony to the uniform weakness of the stern. This is the common point or focus to which all the remarks tend; and therefore, it may be added, without fear of contradiction, that the formation of the stem has decided advantages over the present formation of the stern.
But the change which Sir Robert Seppings contemplates, and which he has actually applied to several ships, is to communicate to the stern the strength and firmness of the bow, and to continue the diagonal system of building which he has lately introduced round the stern, in order to make the strength of the fabric uniform and complete. It is now universally admitted, that the diagonal system has communicated great strength to every part to which it has been hitherto applied; and there seems no good reason why the same increase of strength should not be communicated to a part so notoriously weak as the present square stern, particularly, when, by doing so, not only the mechanical frame of the ship is materially strengthened, but its means of defence also very much increased. Sir Robert, at p. 6. of his Letter, very properly remarks, “ that circular sterns are formed, and in all respects timbered and secured in the same manner as the bow," and that “the strength of the circular stern is equal to that of the bow," and consequently equally well adapted to withstand the shock of the sea. No authority can be more convincing and satisfactory than this, reposing, as it unquestionably does, on the soundest experience, and supported collaterally by so many strong and undeniable truths.
The next point of view in which this important subject may be contemplated, is the consideration of the means which each form of the stern affords for attack and defence.
In the first place, the same objections may be urged against the defence of a square stern, as is known to attach to a redoubt of a square form. “Redoubts,” says Malorti de Martemont, in his Theory of Field Fortification," when they are not flanked by some other fire, have two essential defects; the first is, that their saliants are unprotected, which cannot be remedied, but by adapting to those saliants a few teeth of cremaillère, or when the ground and every other circumstance will allow it, by directing the saliants towards some inaccessible points, or by Vol. I, No. 2.-Museum.
placing in front of them, when possible, some artificial obstacles." * But, continues Malorti, “ Circular redoubts have not that defect, as their fire which has no fixed direction, may incessantly vary, and spread itself on every point of the ground that surrounds them;" and « the defence which they present is uniform on every part of the circumference.” Now, the defects which this able writer attributes to square redoubts, hold in all their force against the defence of the square stern ; while the reasons he gives in favour of redoubts of a circular form, apply most favourably to ships with round sterns. If we may be allowed, by way of illustration, to borrow a few terms from the practice of field fortification, to apply to the mode of defending a ship of war, we may without impropriety say, the “saliants” of the square stern are unprotected; that we cannot apply to those " saliants": a few teeth of cremaillère;' much less direct the " saliants” towards "inaccessible points,” or erect in front of them “ artificial obstacles.” But that the fire of the circular stern is without a “ fixed direction," because it will "spread" itself over every point of the ocean that surrounds it, and moreover, that its defence will be found “uniform” in every part of the circumference. It is true, that the defence of the steru only includes the form of a semicircle, while the defence of the redoubt here alluded to embraces the whole range of its circumference; still the reasoning holds good for the latter figure, as well as for the perfect circle, because the cord of the semicircle, in the case of the circular stern, requires no defence.
And how necessary such a mode of defence may be at times, has been most clearly and forcibly shown by Sir Robert Seppings in several instances. Among those mentioned in his Letter, we may allude to the attack made on the Gibraltar, Northumberland, Terrible, and Powerful, by gun-boats in the Bay of Gibraltar; and also when the Minotaur and Dictator passed the Belt, by gun-boats raking them in a calm. In the retreat also of the squadron of Admiral Cornwallis before the French fleet, they had no means of firing but right aft; and in order to accomplish this, Sir Robert observes “ they were mutilated to such a degree, to enable them to apply their guns, that a refit of no small extent was necessary, before they could be considered again fit for service.”
.“ In the event of future wars,” observes Sir Robert, “ an alteration in the form of the stern of our ships of war would in all probability be absolutely necessary, by which the guns may be worked with greater effect and facility, in consequence of the introduction of steam-vessels: and that America is firmly convinced that a system of attack, by this description of vessels, is not only practicable, but that it will also be destructive in its operations, is not to be doubted. Indeed,” continues Sir R. “I have been told, from good authority, that they have lately well manned one of their frigates, given the command of her to a good officer, and directed an experiment to be tried, if a vessel propelled by steam could not, under any circumstances, lay on the quarter of the ship she attacked, and the result was completely in favour of the steam-vessel.” If we inquire into the cause of this failure, we shall undoubtedly find, that the frigate was incapable of defending her quarter, owing to the square form of her stern,-a circumstance which would not have taken place, if she had possessed one of a cir,cular form.
In case of an attack of the kind just alluded to, Sir Robert Seppings' plan gives a superiority, not only on account of the additional number of guns which the ship is enabled to bring into action, and the sweep of the ocean which those guns are able to command, but also in advantage of another kind, arising from the diminution of the distance of that point from the ship where the shot from the two after guns cross each other, when the guns are trained to their greatest angle,a point, it is presumed, of no small importance in case of an attack from a steam-vessel. In an 84 gun ship with a square stern, this point is distant from the stern, on the level of the gun-deck, about 184 feet, and from the upper deck about 16 feet; whereas in the circular stern, the same point on the gun-deck is distant only 12 feet, and from the
upper deck but 13. In the case of a 60 gun frigate, the distance of a similar point from the square stern is nearly 16 feet, while in the circular stern it is only 9. These united considerations tend unquestionably to prove, that the circular stern is the form best capable of defence.
The sentiments of so distinguished a man as Dupin, on a question of this nature, are entitled to the highest consideration ; and it is most pleasing and satisfactory to peruse the candid and sensible remarks he has made on the subject of round sterns, in his different valuable works. “It is in the sterns of their ships," says he," that the English at this time carry into effect a great improvement. For the future (it is to be wished that the liberal views of Dupin were completely realized in this point) the sterns of their ships are to be circular, composed of timbers, and planked up in the same manner as the sides of the ships. They are to be pierced with ports, shut in with solid port-lids (below). The ships of three decks, for example, present four vertical ranges of four ports each, to fight when in retreat, which, in proportion to the breadth of the ship, present a force equal to that of ships the best armed in their sides. In the (square) stern, the many glazed windows, and the munnions of fir are the only defence; notwithstanding a shot which comes into a ship from aft forward, or from forward aft, causes ten times the destruction which a shot does which comes in at one side and passes out at the other. Act contrary, then,” continues this enlightened author, “ to what has hitherto been the practice, and, if possible, make the means of defence of the part most exposed ten times as great as it now is. Reason, at least, demands that this should be done.
“I ardently wish to see these improvements introduced into our ships. I have constantly repeated, since my first journey into England until this day, every argument, every observation, every experiment, which have appeared to me to carry conviction to the mind. Prejudices and objections, which it is impossible to overcome except by the aid of time, have presented themselves; but over these time will necessarily triumph."
Dupin has alluded to prejudices; and unfortunately objections, having no better foundation, have existed, and do still exist in this country, against this most important plan. Among these prejudices, one may be mentioned, which has given rise to objections respecting the want of beauty in the external form of the circular stern. 'It will not be contended, but that, according to the mode in which the eye has been hitherto educated, the appearance of the square stern is rather