332
being the first iron bar bridge constructed for carriages,and all the ordinary purposes of the country. Dimen-sions, 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 marineslip and cradle-carriage, similar to the “ Queen CharlotteSlip,” at the Royal Dockyard, Deptford (which may beconstructed on the shore of any other river or harbour),on which Her Majesty's frigate “ Solebay” was drawn bya single capstan in three-quarters of an hour, and whichwould, have been accomplished witli a 20-horse powersteam-engine in ten minutes. The cradle-carriage ismounted on the periphery of iron rollers, which circulateover the carriage by an endless chain under the ship’sbottom when in motion; and in some situations thecradle-carriage is moved on a continuous line of rollerslaid down on the ways. In either case, there is a totalabsence of friction; and, as a mechanical power, thesuperiority of the rollers over the multiplicity of smallwheels employed for the same purpose exceeds, in somecases, SO to 1 ; that is to say, it requires 50 times lessforce to move a line-of-battle ship laterally on the waysin the Arsenal on a line of connected rollers, than upontruck wheels of the same diameter, and a proportionatediminution of force 'would take place in drawing shipsin the inclined planes. An important feature in the pro-posed system is, that whatever may be the extent orsituation of the Arsenal, that only one slip or one cradlecarriage and one sliding-off carriage are required for thewhole establishment; that ships intended to be laid upin ordinary, may be disposed of at the more remote partof the yard; that ships could be more expeditiously andeconomically repaired; that any ships may be selectedfrom the line, and transported fully rigged and equipped,without disturbing any other ship, and launched to becompleted afloat for sea.
Fig. 2 is a line-of-battle ship, supposed to be laid upin ordinary, shored up, and the keel resting on the samerollers 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 inthe course of fitting for sea.
Fig. 4. Masting shears, to which any ship may be moved,masted, unmasted, and returned to her position. Theacquisition of this new motive power, which reduces thepropulsive force or traction, by 50 to 1 over fixed axles,renders it perfectly practicable to construct railways(except where tunnels are unavoidable) for the conveyanceof ships, adapted for all the ordinary purposes of tradeand manufacture traffic, with a velocity of 10 to 15 milesan hour, as shown in fig. 5.
Fig. 6. Model of a basin or floating dock, containingan invariable depth of water for the largest ships of war,which may be constructed either by excavation or im-permeable embankments.
Fig. 7. Shows the inclined plane laid down at low water,extending to and carried over the boundary wall, andascending with the same gradient into the basin to floatthe ship off, and no locks or dock gates are required; theevaporation or leakage may be supplied by a sluice athigh water, or from any other source inland. The samesystem, as shown in fig. 8, of raising ships, barges, orother vessels from one level to another, so as to renderlocks altogether unnecessary, may be applied to all the
canals and inland navigation in the country, and ourcolonies abroad.
Fig. 8. Model of the royal chain pier, Brighton, con-structed on a scale of lj inch to a foot, a perfect repre-sentation in detail of the whole structure. The innerchains supporting the platforms are secured to iron re-taining plates in the cliff; the outer chains are supportedby diagonal shores in the centre of the outer pier-liead;the lower extremities are backed on each side by two74-gun ship anchors, driven to a considerable depth intothe chalk rock. It was begun in November, 1822, andfinished in November, 1823.
[The Brighton chain-pier, opened in November, 1823,was designed by Capt. Sir Samuel Brown , R.N., who firstsuggested that the chains should be made of long fl atbars with holes drilled in their ends, by which the}'might be connected together by short links and pins. H epatented this invention in 1817.—S. C ]
Fig. 9. Model of the mariners’ compass, exhibiting thepoints on a vertical belt or zone, where they may be seenin all directions, at any desired altitude above the deck.
Fig. 10 . Model of a brass columnal bearing and distancerevolving lighthouse, designed for the great Haiioisrock, 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 clearweather, at the distance of 12 miles; the second altitudewould be seen at the distance of 10 miles; and the thirdaltitude 8 miles. The metal dome, 10 feet in diameter,would be tempered into a bell the largest and niorisonorous in the world, aud would be struck at intervals,during fogs or thick weather, to warn against danger.
There would be ample accommodation for the light-keeper ; and also provisions and stores for four months,or longer, if necessary. The total expense of erectingand completing the brass column ready for the receptionof the light of the first order would be 10,0007.; time ofexecution not exceeding six months; and its stabilitywould be guaranteed for seven years.
[Sea water lias an injurious action upon cast-iron ; brass,however, effectually resists its effects, hence its value forthe tower of a lighthouse erected in the sea. Doublelights are used as distinguishing them from neighbouringlights. Lights are obscured by fog, and therefore a con-trivance, such as a fog-bell, by which the seamen can bewarned of danger is desirable.—S. C.]
Fig. 11. Model of part of a railway, with a centre guhlj.rail to prevent the engine or carriages from runningthe rails. Model of a set of railway carriages; the ax*®pass between the bodies of two, which places the weigh*below instead of above the centre of motion and traction,and admits of an increase of the diameter of the wheelin the ratio of five to three, diminishing resistance to t®motive power in the same ratio. They may also ®adjusted to suit both gauges.
Fig. 12. Model of the main and after body of a slopfitted with submarine steam propellers; applicable a * sto a life-boat.
Fig. 13; Model of two pair of midship timbers, or n®®jof a line-of-battle ship; the butt end secured ^wrought-iron or gun-metal plates, let in flush, wh> crender the joints nearly as strong as the solid timber.
Fig. 14. Model of an equipoised bed, or sofa, ull inturbed by the ship’s motion at sea.