MR. MURRAY'S INVENTION FOR SAVING FROM SHIPWRECK.

Several ingenious methods have been proposed for effecting a safe communication between stranded ships and the shore. Mr. Trenghouse suggested a rocket, Captain Dansey a kite, and Captain Manby a shell, for the purpose of carrying out a line to the ship in distress. The plan of Captain Manby was thought so well of at first, that it was honoured with a Parliamentary reward, and very great exertions have been made to introduce it into general use. But it has been found attended with so much difficulty, even under the most favourable circumstances, and has in not a few instances failed so decidedly, that it has been only very partially adopted, and has not effected any material diminution in the general loss of life by shipwreck. From the weight of Captain Manby's apparatus, it is not quickly transportable from the few stations which are provided with it, to the immediate scene of danand when the rope is projected it ger; too frequently snaps in two. A transport was wrecked only three miles from Mundesley, where there was one of Captain Manby's safety-mortars, but before it could be conveyed to the spot the ship had gone to pieces, and all on board perished. In another case, of a ship wrecked off Whitby in 1820, within 60 yards of the shore, the shot, in the first attempt, fell short; the rope, in the second, broke; and the ship and crew were buried in the breakers. On many parts of the coast there is not even this imperfect apparatus of Captain Manby. So late as December, 1830, one of the most frequented, and, at the same time, most dangerous parts of the British coastthat between Plymouth and the Land's End-was so entirely destitute of every sort of means for saving shipwrecked mariners, that of the passengers and crews of 28 vessels which went on shore in the dreadful storm of that month, only two men and a boy were saved!

Frequent reflection on these distressing facts has led Mr. John Murray (the popu lar lecturer on chemistry, and the author of many excellent scientific works) to the invention of the apparatus represented in the prefixed engravings, and described in a pamphlet which we have now be

fore us.* Mr. Murray first tried to project from a common musket an arrow with a line attached to the feather end, but the arrow became reversed in its transit through the air, and the following improved and very ingenious arrangement was therefore adopted :

"The highest figure represents the form of the arrow, as best constructed for the common blunderbuss, and may be propelled immediately from the shore, or carried with the life boat. The butt-end carries a thin metallic shield, or plate, which may be made of copper. The point is sharp and barbed, to fasten where it may strike, or act as a holdfast on the tackling or rigging of the wreck. It is shod with iron, as well to subserve this purpose as to secure its direction, and compete with the resistance it must encounter in a storm. The wood used is hiccory, or ash, or, still better, lancewood, the more cohesive the fibre the better; this is withed in its extreme length with whip thread or line; bands or ribbons of thin metal strengthen the arrow, where the bent extremities of the parallel iron rod pass through, and which last are further secured by a shoulder on one side and a nut on the other. Along this parallel rod glances the iron ring to which the line is attached, the instant it leaves the gun, and a bit of cork, or caoutchouc, toward the end of the arrow, interposed between the rod and the body of the arrow, acting as a recoil spring, will so far subdue the effect of friction.

"The entire weight of the arrow, thus plumed and shod, is from two to three ounces, eighteen inches long, and three quarters of an inch in diameter. These dimensions and weight have been found most efficient and successful when applied to a blunderbuss sixteen inches long in the barrel, and 1 inch diameter ia the calibre. The entire weight of the arrow and its appendages, together with the strong whip-cord attached to it, was two pounds and one ounce, and were carried to an extent of nearly one hun dred yards by two drachms of gunpow der. The cord was of sufficient strength to pull a rope from the shore large enough to form a communicating medium of escape from the wreck.

"The lowest figure exhibits the ar row applied to a three-pounder swivel, the calibre of which, however, though

* Invention of an Effective and Unfailing Method for forming an Instantaneous Communication with the Shore in Shipwreck; and Illuminating the Scene in the Dark and Tempestuous Night. By John Murray, F. S. A. &c. 30 pp. 8vo. Whittaker and Co.

not represented in the plate, it ought nearly to fill. In this case, the arrow and its various adjustments weigh to. gether nearly two pounds; and with three ounces of gunpowder a line of considerable strength and power will be propelled upwards of a hundred and fifty yards. In this instance a macharel, or deep sea-line, may be used. The cord is represented as coiled in the form of what is called French faking, and was the plan adopted in all our experiments, while it seems best adapted to preserve the coils from being entangled-a circumstance of the highest importance in experiments of this description. The barb is removed here to render the appearance less complicated.

"The arrangement is supplied with an appendage for illuminating the flight of the arrow and scene of shipwreck. It consists simply of a cylindrical sheath, or socket, containing the materials of illumination, consisting of a mixture of finely-powdered chlorate of potassa and sugar-candy intimately blended together. A spindle supplied externally, with a flat head, enters by its extreme end into a miniature phial supplied with sulphuric acid, sealed with a drop of bees' wax. As soon as the arrow leaves the gun, the reaction of the air on the head of the spindle drives inward the plug of wax and liberates the acid, which instantly kindles the mixture, the brilliant flame immediately fills the globular cage of wire gauze which surmounts it, and the intensity of the light is rendered still more dazzling and splendid by adding a bit of phosphorus to the inflammable powder. This part of the apparatus is made altogether independent of the arrow, and may be easily attached when circumstances require it, as when the darkness of the night renders it imperative. The combustion which forms the source of the illumination, cannot be quenched either by the sea spray or a deluge of rain, the medium of support being supplied from itself, altogether independent of the external atmosphere, however charged with watery vapour or rain, and the combustion is too fierce to be at al affected by the wind, even at its maximum degree of strength.'

The "experiments" alluded to in the preceding extract are detailed more at length in a subsequent part of the pamphlet, and leave no doubt on our minds, that Mr. Murray's apparatus is by far the most efficient that has yet been devised; while, at the same time, it is so cheap and portable, that inclination alone is all

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that can be wanting to bring it into universal use.

DRURY'S CLOCK HAMMER.

"The great expense attending the manufacture of turret clocks is occasioned by the magnitude of the machinery, which is necessarily employed in raising a ponderous hammer, which shall strike with sufficient force on a large bell, to produce a sound capable of being heard at a distance from the clock, so as to be useful to the surrounding neighbourhood. cannot fail to be evident to everyone acquainted with the subject, or to any mechanical gentleman who would take the trouble to examine the hammer-work of turret clocks, that a great portion of the force of the percussion of the hammer, is lost before it comes in contact with the bell, and, consequently, a great deal of power is exerted in vain, in listing them. The counter-spring of the hammer (a spring which supports the hammer from resting on the bell) opposes considerably greater resistance to the blow than the actual weight of the hammer, because it has the power of supporting it much above that part of the bell on which it strikes. The friction that takes place between the counter-spring and the ham-. mer is very great, in consequence of the rust which it unavoidably contracts by its necessary exposure to the open air; and I think I should not over-rate both. these resistances, if I estimated them at equal to twice the weight of the hammer."*

Sir, Although it is true that much of the evil, described by Mr. Wynn in the preceding paragraph, arises from the unskilful and injudicious manner in which the mechanism is arranged, especially in the connection of the hammer with the clock; yet, it is pretty evident that the principle hitherto employed, is, in itself defective. Various attempts have, from time to time been made, to construct a clock hammer without a counter-spring, among which that of Mr. Wynn is the most conspicuous; who, although he certainly dispensed with the counter-spring, yet the machinery which he substituted for it was so complex and expensive in its construction—and so uncertain in its action-that the remedy became very much worse than the disease.

The subject of clock-hammers happening to engage the attention of Mr. Drury, a few years since, he invented a new form of hammer, in which all the evils of the old one are completely obviated, and possessing in an eminent degree all the necessary advantages of simplicity, efficiency, and cheapness.

Drury's clock-hammer applied to one of his improved bells, is represented in the accompanying sketch ;* where, upon a strong frame or platform A A, is fixed the bell B, as also a strong axis or pivot e; upon this axis the lever dd vibrates freely; upon the same axis also works the hammer E. f is a powerful coiled spring secured by one end to the platform at g, the other end being fastened to the central part of the lever d d, and exerting a constant tendency to turn it in the direction of the arrow; motion in this direction is however prevented by the head of the lever resting upon the stop H.

Above, and a little to the right of the centre c, the lever rises and abuts forward-forming a shoulder, upon which the hammer-arm rests by the influence of gravity; the hammer, when in this position, being within a few inches of the bell. I, is the clock wire, attached to the tail of the lever, by a hook placed in a hole made for that purpose; several of these holes occur at different distances from the centre of motion, any of which may be used to suit the power of the clock, length of pull, &c. &c.

In striking, the clock pulls down the tail of the lever dd (to which it is attached by the wine I) a few inches; the hammer still rests upon, and follows the motion of the lever, falling through the space assigned to it; the spring is at the same time coiled up tighter than before. The clock suddenly releasing its hold of the lever, the elastic property of the spring immediately brings, it back into its former position, carrying with it the lever, which flies up and is caught by the stop H; but the hammer, which has partaken of the motion of the lever, being free to continue its course, is carried forward by the great momentum that has been communicated to it, and strikes a forcible blow upon the belldue to the weight of the hammer and the velocity with which it was moving. The blow having been struck, the ham

See front page.

mer-partly by the re-action, and partly by the influence of gravitation-falls back upon the shoulder of the lever, and there remains until another blow is to be struck, when the process is repeated.

Although the above is a pretty correct sketch of a hammer, fitted up by Mr. Drury some time since, yet, the object of this communication is to explain the principle of the invention, rather than the mechanical arrangement. For the principle may be applied with almost equal effect, in fifty or a hundred different ways; it may be applied to bells of any form or size, and they may be struck either within or without; the lever may be straight, circular, or angular; and the spring may be either coiled, straight, or curved. Under any of these, or any other modification of mechanical arrangement, the principle is so simple, so perfect, and the facility of adjustment so great, that a successful action may always be depended upon.

All the numerous and highly important advantages, that have been expected to accrue from an improvement and simplification of the clock-hammer will most assuredly be obtained by adopting Drury's hammer.

With this hammer, a very considerable reduction will be made both in the weight, and also in the machinery, hitherto necessary to strike upon a given bell.

In new turret-clocks, however, by the introduction of Drury's bells, as well as his hammer, the reduction in size, and, consequently, in expense, will be very great indeed.

An application of this hammer, deprived of its spring, &c., to the purpose of a tolling-hammer I have already described at page 282 of your 12th volume. Yours, &c., W. BADDELEY. Dec. 22, 1831.

REGULATION OF STEAM-VESSELS-SIR ROBERT SEPPINGS' DIAGONAL SYSTEM. Sir, I thank you for the able manner in which you have exposed the absurdities of the Report on Steam Navigation, drawn up by the Committee of the House of Commons. Were it not for the tragical effects so frequently produced by such specimens of legislation, they would really form an admirable subject for mirth; but the people, who are losers by such matters, cannot afford, to laugh.

The prescription for placing a light at the stern under the gunwale," in order to be seen in front, is unique in all ways. Lighting a candle, and putting it under a bushel, will after this cease to be an absurdity. But, surely, there must have been some new discovery in the art of shipbuilding, which is hitherto only known amongst legislators. I have often heard of the taff-rail of a ship, but a stern-gunwale is something novel. These gentry appear to possess the same crude notions of vessels as the good old lady in Cooper's romance of the Red Rover, who, in the height of her enthusiasm, talked quite poetically of a ship cutting the waves with her taff-rail," i. e. literally going stern foremost, a quality which few skippers would covet as an attribute of their vessels, unless perchance they belonged to the Ladrone Islands, and were constructed to sail either way.

The "head and front of the offending," on the part of the steam-boats, seems to be, that they occasionally swamp wherries and barges loaded to the water's edge, by the swell and undulation they occasion in the river. A simple observer would have supposed, that the short way to remedy the evil would be to make wherries illegal, as a conveyance for passengers; and to oblige the barge-owners to build their barges with another streak. It is agreed on all hands, that steamboats are very useful vessels; and if the Legislature has a right to dictate to them, it has a right also to interfere with the barges and wherries. But the wisest way is to interfere as little as possible, and leave the matter to be settled by those interested in it, unless in cases which may involve the loss of life, to such persons as may not be aware of the danger they are risking. Therefore, all passage-vessels are fairly objects of legislation, so far as sea or river-worthiness goes.

The regulation of the speed of steamvessels is exceedingly absurd, and still more so is the means of regulation by the prescription of the number of revolutions the paddle wheels are to perform in a minute. This is something like the device of the tread-mill, whereby the giant and the dwarf are reduced to take the same strides. The fact, that the slow motion of the paddle-wheel will produce a greater undulation of the water than the rapid motion, seems so self-evident, that it is wonderful how the drawers-up

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of the Report could avoid stumbling on it. Up to a certain point, pressure ap plied to a surface of water, will affect a mass to a great distance. Increase the pressure, and the mass will be broken. Thus, the slow motion of paddle-wheels undulates the water, and the rapid motion churns it; just as a small pressure or weight applied to a flexible rod will merely bend it, and a greater weight will break it.

Captain Hall seems to be keeping up the charter of his politics, in making ab solute command the rule of all legis lation. These are quarter-deck maxims, which he has been accustomed to all his life. Having served his time to unresisting and irresponsible obedience, in the expectation of afterwards changing from slave to master, like the Egyptian Mamelukes, he thinks it rather hard he should now be deprived of the recompense which he has worked up hill to obtain. This is a very common case; but he must submit to it, for people are more enlightened than of yore; and, like other persons who have made bad calculations, he must put up with his loss of time without grumbling. has experienced some slight gratification in the possession of arbitrary power during his voyages in the Indian Seas and the Pacific, and though he met with a sturdy resister of his dictation in money transactions, in the person of the Chilian Vice-Admiral Cochrane, still he has been a dictator to some extent, and if he wishes to continue the practice, he had better, like Dionysius, of Corinth, set up the trade of a schoolmaster, as at present practised, for, alas! even that bids fair to assume another form, in which arbitrary power will be at an end.

He

The plan of Sir Robert Seppings for building vessels solid, and planking their exterior diagonally, is subject to many objections. It consumes a double portion of precisely that kind of timber which is the most difficult to procure, viz., curved scantling; and it adds an enormous extra weight of unbuoyant matter. Solid sides might be of advantage in a ship of war, for the purpose of resisting cannon balls; but the single convenience of inspection, could not by any means compensate for the numerous disadvantages such a mode of construction would offer in a steam-boat; the object of which is, swiftness, combined with all