1851 Great Exhibition: Official Catalogue: Class VIII.: Samuel Brown
334 BROWN, Sir SAMUEL, R.N., Vanbrugh Lodge, Blackheath — Inventor.
Iron cables invented and introduced into the Royal Navy by Captain Sir Samuel Brown, R.N. K.H., in 1810.
Nos. 1 and 2. Patterns of the twisted and plain parallel-sided chains, the iron 11 inch diameter without stay-pins, which was proposed by the exhibitor to the Admiralty as a substitute for hempen cables in 1810. The twisted chain was preferred by the Board for this purpose, by reason of its resemblance to the strands of a rope, and on that account supposed to be more easily managed as a working cable.
No. 3 is a single link of the same dimensions, with a short scarf ready for welding in the end: this, which was practised in all the Royal Dockyards, and by all the chain-makers in the country, was radically bad, because the weld is inevitably the weakest part; was subjected to a transverse strain at the point of resistance, where a small defect was more detrimental than any other part; the inventor therefore adopted the plan of forming the weld in the direction of its length in the side, where the strain is equally divided.
No. 4 is a single link showing the long scarf in the side ready for welding, as above mentioned.
Origin of the Stay-pins.— When the chain-cables were first brought into use (which was in the Navy) there was no means of testing their strength, and two ships, the "Pique," 38-gun frigate, and the "Pylades," sloop-of-war, having both parted their cables in a heavy gale and sea, it was found that the links, in the technical phrase, had drawn in the strain. The inventor of the iron cables thereupon devised a powerful compound lever-machine for testing all cables to a given strain. The first cable to be tested was a twisted cable, welded in the side with long double scarp, but without stay-pins, inches diameter, against a piece of new 24-inch cable, which was the largest size made; the cable and the chain were shackled together, so that the strain was reciprocal. The trial took place at the manufactory in Shadwell, in July, 1810, in the presence of Lord Melville, First Lord of the Admiralty; Sir J. B. Thompson, Comptroller of the Navy Board; the Chancellor of the Exchequer, Mr. Vansittart; the Surveyor and Commissioners of the Navy, and several Naval Captains. In the course of the trial, as the hempen cable continued to stretch, and the chain to collapse, the machine was at that time stopped; and then three wrought-iron pins similar to those shown in No. 5 were inserted in the middle of the links: the process recommenced, and the pins were in a short time set fast. Four hours had been occupied in this interesting experiment, when the hempen cable began to give way, and was ultimately broken in the direction of its length with a force of 84 tons; no fracture had taken place in the iron cable, and the links which had been distended with the pins preserved their shape; but all the others had collapsed and become perfectly rigid, and, of course, totally, useless. The improvements thus introduced in the construction of the iron cables, and the system of testing, were of infinitely more importance than the original invention, and which were all carried into effect in 1810, two years before any other chain-cable manufactory was in existence.
No. 5. Pattern of the parallel-sided chain, proposed by the inventor to supersede the twisted cables in 1812. The first cable was supplied to His Majesty's frigate "Crescent" in that year, which, being favourably reported on, he received directions from the Admiralty to prepare a schedule, in conjunction with Mr. Goodrich, mechanical engineer at the Royal Dockyard, Portsmouth, of the form and dimensions of chain-cables, which, with very little modification, is at present the standard for all classes. The chain cables, which are of oval shape, are susceptible of still further improvements, for it has been observed, in the course of an extensive practice, that, in testing chains to prove the quality of the iron, links gradually collapse, and that the rupture does not take place till the sides are drawn nearly into contact; it, therefore, occurred to the inventor that the inverted oval link, No. 7, as approximating in some degree to this ultimate form of resistance, was stronger, inasmuch as the present distended oval link is a departure from it; and there can be no doubt that, as the convex links fit more uniformly to the cylindrical bells or windlass, they would work smooth, and with less jolting in veering.
[It was this invention of Capt. Brown which first rendered the knowledge of the strength of malleable iron indispensable. Chain cables with the simple oval link resist a strain of 21.5 tons per square inch, the mean strength of wrought-iron being 25 tons per square inch. When stays between the sides of the links are introduced, the strength is very nearly equal to that of the iron in the simple bar form, so that a stay may be said to increase the strength by about 1-6th part. The links of Mr. Price's chains are made with parallel sides, so that the fibres of the iron are kept in the direction of the strain; their strength is therefore greater than that of the simple oval links, which have a tendency to alter in form, or elongate.— S. C.]
Picture in oil of the Union Suspension Bridge, erected over the Tweed in 1820, connecting England and Scotland, being the first iron bar bridge constructed for carriages, and all the ordinary purposes of the country. Dimensions, 420 feet span between the points of suspension, supported by 12 lines of cylindrical wrought iron bars, containing 24 square inches.
Models.
Fig. 1. Model of an inclined plane, or patent marine slip and cradle-carriage, similar to the "Queen Charlotte Slip," at the Royal Dockyard, Deptford (which may be constructed on the shore of any other river or harbour), on which Her Majesty's frigate "Solebay" was drawn by a single capstan in three quarters of an hour, and which would have been accomplished with a 20-horse power steam-engine in ten minutes. The cradle-carriage is mounted on the periphery of iron rollers, which circulate over the carriage by an endless chain under the ship's bottom when in motion; and in some situations the cradle-carriage is moved on a continuous line of rollers laid down on the ways. In either case, there is a total absence of friction; and, as a mechanical power, the superiority of the rollers over the multiplicity of small wheels employed for the same purpose exceeds, in some cases, 50 to 1; that is to say, it requires 50 times less force to move a line-of-battle ship laterally on the ways in the Arsenal on a line of connected rollers, than upon truck wheels of the same diameter, and a proportionate diminution of force would take place in drawing ships in the inclined planes. An important feature in the proposed system is, that whatever may be the extent or situation of the arsenal, that only one slip or one cradle carriage, and one sliding-off carriage are required for the whole establishment; that ships intended to be laid up in ordinary, may be disposed of at the more remote part of the yard; that ships could be more expeditiously and economically repaired; that any ships may be selected from the line, and transported fully rigged and equipped, without disturbing any other ship, and launched to be completed afloat for sea.
Fig. 2 is a line-of-battle ship, supposed to be laid up in ordinary, shored up, and the keel resting on the same rollers on which she was drawn up.
Fig. 3 is another line-of-battle ship similarly supported, with her lower mast in, supposed to be under repair, or in the course of fitting for sea.
Fig. 4. Masting shears, to which any ship may be moved, masted, unmasted, and returned to her position. The acquisition of this new motive power, which reduces the propulsive force or traction, by 50 to 1 over fixed axles, renders it perfectly practicable to construct railways (except where tunnels are unavoidable) for the conveyance of ships, adapted for all the ordinary purposes of trade and manufacture traffic, with a velocity of 10 to 15 miles an hour, as shown in fig. 5.
Fig 6. Model of a basin or floating dock, containing an invariable depth of water for the largest ships of war, which may be constructed either by excavation or impermeable embankments.
Fig. 7. Shows the inclined plane lain down at low water, extending to and carried over the boundary wall, and ascending with the same gradient into the basin to float the ship off, and no locks or dock gates are required; the evaporation or leakage may be supplied by a sluice at high water, or from any other source inland. The same system, as shown in fig. 8, of raising ships, barges, or other vessels from one level to another, so as to render locks altogether unnecessary, may be applied to all the canals and inland navigation in the country, and our colonies abroad.
Fig. 8. Model of the royal chain pier, Brighton, constructed on a scale of 1.25inch to a foot, a perfect representation in detail of the whole structure. The inner chains supporting the platforms are secured to iron retaining plates in the cliff; the outer chains are supported by diagonal shores in the centre of the outer pier-head; the lower extremities are backed on each side by two 74-gun ship anchors, driven to a considerable depth into the chalk rock. It was begun in November, 1822, and finished in November, 1823.
[The Brighton chain-pier, opened in November 1823, was designed by Capt. Sir Samuel Brown, RN., who first suggested that the chains should be made of long flat bars with holes drilled in their ends, by which they might be connected together by short links and pins. He patented this invention in 1817.— S. C.]
Fig. 9. Model of the mariners' compass, exhibiting the points on a vertical belt or zone, where they may be seen in all directions, at any desired altitude above the deck.
Fig. 10. Model of a brass columnal bearing and distance revolving light-house, designed for the great Hanois rock, on the south-west coast of the Island of Guernsey. The centre of the light would be 130 feet above high-water mark, spring-tides, and distinctly visible in clear weather, at the distance of 12 miles; the second altitude would be seen at the distance of 10 miles; and the third altitude 8 miles. The metal dome, 10 feet in diameter, would be tempered into a bell the largest and most sonorous in the world, and would be struck at intervals, during fogs or thick weather, to warn against danger.
There would be ample accommodation for the light-keeper; therefore, provisions and stores for four months, or longer, if necessary. The total expense of erecting and completing the brass column ready for the reception of the light of the first order would be £10,000; time of execution not exceeding six months; and its stability would be guaranteed for seven years.
[Sea water has an injurious action upon cast-iron; brass, however, effectually resists its effects, hence its value for the tower of a lighthouse erected in the sea. Double lights are used as distinguishing them from neighbouring lights. Lights are obscured by fog, and therefore a contrivance, such as a fog-bell, by which the seamen can be warned of danger is desirable.— S. C.]
Fig. 11. Model of part of a railway, with a centre guide rail to prevent the engine or carriages from running off the rails. Model of a set of railway carriages; the axles pass between the bodies of two, which places the weight below instead of above the centre of motion and traction, and admits of an increase of the diameter of the wheels in the ratio of five to three, diminishing resistance to the motive power in the same ratio. They may also be adjusted to suit both guages.
Fig. 12. Model of the main and after body of a ship fitted with submarine steam propellers; applicable also to a life-boat.
Fig. 13. Model of two pair of midship timbers, or ribs, of a line-of-battle ship; the butt end secured with wrought-iron or gun-metal plates, let in flush, which renders the joints nearly as strong as the solid timber.
Fig. 14. Model of an equipoised bed, or sofa, undisturbed by the ship's motion at sea.