THE " GREAT EASTERN."

Otago Witness, Issue 317, 26 December 1857, Page 3

THE " GREAT EASTERN."

(From the Spectator, September 12.) -V The journals are full of details respecting the Great Eastern steam-ship, whose launch we are promised early in October. From them we cull some statements which may interest the reader. ■ - * " Two walls of iron, about sixty feet high, divide the vessel longitudinally into three parts; the inner the boilers, .the engine-rooms, and the saloons, rising one above the other; and the lateral divisions the coalbunkers, and above them the side-cabins and berths. The saloons are sixty feet in length, the principal one nearly half the width of the vessel, and lighted by skylights from the upper deck. On either hand are the cabins and berths; those of first-class passengers being commodious rooms, large enough to contain every requirement of the most fastidious of landsmen. The thickness of the lower deck will prevent any sound from the engine-rooms reaching the passengers, and the vibration from being at all felt by them. On each, side of the engine-rooms is a tunnel, through which the steam and water-pipes will be carried, and also rails for economizing labour in the conveyance of coal. The berths of the crew are forward, below, the forecastle, which it is intended to appropriate to the officers, whose apartments are at present only marked by a few uprights, rising ten or twelve feet above the main deck. Below the berths of the seamen are two enormous cavities for cargo, of which 5000 tons can be carried, besides coals enough for the voyage to Australia, making abput as many tons more. The weight of this huge ship being 12,000 tons, and her coal and cargo about 18,000 tons more, the motive power required to propel her twenty miles per hour must be proportionate. If the visitor walks aft and looks clown a ..deep chasm near the stern, he will perceive an enormous metal shaft 160 feet in length, and weighing 60 tons; this extends from the engine-room nearest the i stern to the extremity of the ship, and is destined to move the screw, the four fans of which are of proportionate weight and dimensions. If he walk forward, and look over the side, he will see a paddle-wheel considerably larger than the circle at Astley's; and when he learns that this wheel and its fellow will be driven by four engines having a nominal power of 1000 [-horses, and the screw by a nominal power of 1600 horses, he will have no difficulty in conceiting a voyage to America being performed in seven day?, and to Australia in thirty-five days.. The screw engines, designed .and manufactured by Messrs. James Watt and Co., are by far the largest ever constructed ; and, when making fifty revolutions per minute, will exert an effective force of not less than 8000 horses. It is difficult to realize the work which this gigantic force would perform if applied to the ordinary operations of commerce. It would raise 132,000 gallons of water to the top of the Monument in one minute, or drive the machinery of forty of the largest cotton-mills in Manchester, giving employment to from 30,000 to 40,000 operatives. The consumption of coal to produce this amount of locomotive force is estimated at about 250 tons per day. The four cylinders weigh about 25 tons each, and are 84 inches in diameter. The crank shaft, to which the connecting-rods are applied, weighs about 30 tons. The boilers are six in number, having 72 furnaces, and an absorbent heating-surface nearly equal in extent to an acre of ground. The total weight exceeds 1200 tons; and yet they are so admirably contrived that they can be set in motion or stopped by a single hand. Sails will not be much needed j for in careering over the Atlantic twenty miles per hour, with a moderate wind, they would impede rather than aid progression ; but in the event of a strong wind arising, going twenty-five miles per hour in the course of the vessel, sails may be used with advantage ; and the Great Eastern is provided, accordingly, with seven masts, two square-rigged, the others carrying fore and aft sails only. The larger masts will be iron tubes, the smaller of wood. The funnels, of which there will be five, are constructed with double casings ; and the space between the outer and inner casings will be filled with water, which will answer the double purpose of preventing the radiation of heat to the decks, and economizing coal by causing the water to enter the boilers in a warm state. Her rigging will probably cause more disturbance of ideas to nautical observers; for, besides the unusual number of masts, she will want two of the most striking features of . all .'other vessels, namely, bowsprit and figure-head. Another peculiarity ; is the absence of a poop." The captain's apartment is placed .amidships, immediately below the bridge ; whence the 'electric telegraph- will flash the com manner's, orders to the engineer below',' helmsman- at the' wheel, and look-out man at the bows// Tn' iron' Vessels great /precaulions are necessary to prevent the compass

from being* influenced by the mass of metal in such attractive proximity, and various exfteri-. ments have^been made with the view of disco- £< vering the best mode of overcoming this drrßfe^ culty., It was originally intended to locate the compass upon a stage forty feet high ; but this plan has been abandoned, and a standard compass will be affixed to the mizenmast, at an elevation beyond the magnetic influence of the shipj She will have four of Trotman's anchors, each weighing 7 tons, and two small anchors of 5| tons, at the forward part of the ship. At the stern 'th^re will be two anchors of 6 tons each. The chain cables are likewise en suite. There will be two forward of 2|-inch diameter (about 601b. the link), and two of 2|-inch diameter. In. the after part there will be two of 2|-inch, and each cable will be 140 fathoms long. The total number of crew will be 400, of which one-third will belong to the engineering department, one-third for victualling and servants, and one-third the sailing department. The officers will be Captain W. Harrison (late of the Cunard's line), a chief officer and chief engineer, twelve other sailing officers, sixteea subordinate engineers, a sailing master, a purser, and two or three surgeons. In addition to the two screw-steamers which will hang astern abaft the paddle-boxes, and each of which will be 100 feet long, 16 feet beam, 120 tons burden, and 40 horse power, there will be 21 other boats, which are now being made at Deal. Some of these will be large decked boats, like little yachts, and all will be fitted with masts and sails complete.

" Whatever misgivings may be felt as to the length of the vessel, and the great weight she will carry amidships, will be set at rest before she even touches the water by the mode of launching — an operation which will be as great a novelty as the ship heiself. The plan hitherto has been to build the vessel on an inclined plane, and at right angles with the water ; but in the case of the Great Eastern this was impossible, on account of her great length, to say nothing of the expense of building a vessel of her enormous dimensions in a position which would elevate her forecastle nearly 100 feet above the ground. These considerations led Mr. Brunei to determine upon launching her sideways ; with which view she has been built parallel to the river. In constructing the foundation of the floor on which she stands, provision has been made at two points to insure sufficient strength to bear the whole weight when completed. On these two points she will rest when ready, and thus her strength will be tested in the severest "and therefore most satisfactory manner. Two cradles will be introduced at these points, and she will then be moved by two powerful hydraulic engines. Timber ways are laid down to lowwater mark, with an incline of one foot in twelve, and iron rails of peculiar construction are to be laid upon these transversely. A telltale will indicate the rate at which the two ends are descending, and any difference that may occur will be immediately rectified by strong check- tackle. It is calculated that she will advance twelve feet per minute ; at which speed her submersion will be effected in twenty minutes. The cradles will then be drawn from, under her; and she will then be towed over to the opposite side of the river, where she will lie until -ready for sea."

A New Application of Machinery. — Mr. John Whines, foreman of joiners at the wellknown firm of G. Smith and Co., Pimlico, has patented a machine for dovetailing, grooving, slotting, and rabbilting, by the aid of which an ordinary workman can produce in a superior manner as much as six skilled workmen by the ordinary method. It is perfect in its operations, for boxes, drawers, carcases of bookcases, ■wardrobes,- &c, upon any description of mate-: rial from \ inch to 1^ inches in thickness and ' from 1 inch to 22 inches in width, its range being quite capable of meeting the ordinary requirements of a joiner's or cabinet maker's shop. For any special purpose, a larger machine could be constructed upon the same principle. The article to be dovetailed requires neither marking nor setting out, nor any fitting or hand labour after leaving the machine, but simply glueing and putting together. We have seen specimens of dovetailed work executed by. the machine, and are certain that' it could not be equalled by hand labour, without the utmost care. The machine is also exceeding useful for bead and flush framing; for cutting or rabbitting the ends of panels, mitreing the beads thereon, and also the beads to be inserted, which operations it also performs expprlkiousl y, and in a perfect manner; in short, it is capable of mitreing any 'kind of mouldings, whether stuck on the solid or planted in. It is also fitted with a suitable block ttnd cutterfor forming saw teeth, racks for moveable bookcase shelves, and for he veiling the ends of cross bearers to support the same. The .whole of its operations are performed with accuracy and dispatch, without any of the tedious work of setting out, the machine itself performing all that is necessary. — Mechanics 1 Magcczine,- August. v A Large Farm. — The farm now cultivated by Alan Pollock, Esq., in the' west of Ireland,,, , consists of 20,000 acres. There &r& at present ■ .under turnips 2000. acres ; oats,' 3Qoo;,Vheat,-; 1200.; potatoes, 400. : He.'has "10()p.;head- of,- ; cattle for stall feeding, 400 workfa^h'oir-ses&an^r;? 'pays £4000.-aioTithly^m ; Vag:esi>:T^h'er.e|hia;ve|£* been erected onV,it 'fifty -miles pf.l&tone|^all|^ fences. — Sounders' -News-latteni-ikU^ >|'^ :^'^