UNDER the above designation, a " life-boat," or what would be more correctly termed a life-raft, has been constructed by two public- spirited gentlemen, the Messrs. RICHARDSON, of Aber Hirnant, Bala, North Wales, and navigated from Liverpool, round the Land's End, to Ramsgate and London, having, in the course of the voyage, encountered some severe weather, and sufficient, in their opinion, as also in that of the coxswain of the Magazines Life-boat at Liverpool, THOMAS EVANS (a high authority on such a subject), to establish the fact that a raft of that construction may be made to answer all the purposes of a life-boat, except, perhaps, beating to windward, for which obviously such a form is not adapted, although by means of lee-boards, and the use of the lee- oars, she goes to windward fairly.

The life-raft in question consists of two iron tubes, cylinders or pontoons, 40 ft. long, by 2£ ft. diameter, placed side by side, at a distance of 3 ft. apart; the ends tapered, curved, and turned inwards, so as to meet in a point at head and stern. The cylinders are divided into water-tight compartments, are well stayed and braced together, so as to form a rigid fabric. On the top of this, which forms a frame, narrow beams are laid athwartships, and at about an inch apart battens are laid lengthways (so that water may pass between), and thus form a plat- form, 30 ft. long. The head and stern sheets have a rope net-work instead.

Above the platform, sides about 8 in. high, extend fore and aft, on which the thwarts are fixed; and again above these a gun- wale, 12 in. high, in which the rowlocks are placed. The thwarts are 8 in number, 36 in. apart from centre to centre, but they are only 4 in. above the platform amidships.

The width of the platform is 6 ft. 8 in., the whole width of the raft is 8 ft. It is pulled with 14 or 16 oars, like an ordinary boat, steered by a rudder, and rigged with 2 lug- sails, with a jib and top-sails for fine weather.

It will carry 80 men, and such is its stability that, if they all stood on one side, it would make no great difference. The weight of the whole is 53 cwt., and its draft of water said to be only 11 in. It was built by Mr. William Lees, of Manchester, and appears well and strongly put together; the thickness of the cylinder iron is IVth of an inch, and openings are provided in the top of each compartment for pumping out any water that may get into them. The four end compartments are filled with air-tight bladders, and the two middle with cork shavings. The cost of the whole, it is understood, was 130?.

This raft is said to have behaved very well on its passage round from Liverpool to London ; it encountered some rough weather in passing through Jack Sound, oft' St.

David's Head, and in the Bristol Channel, off Padstow. The coxswain declares that no sea ever broke over them, but that the raft rose buoyantly to the waves. On a trial in smooth water, off Woolwich, it held way fairly with a life-boat. No opportunity has yet been afforded for trying its powers in pulling off shore against a gale of wind to a wreck, but she has frequently beached and rowed off again in a strong breeze.

The spirited owners have left their craft at Messrs. Searle's, the well-known boat- builders at Lambeth, who will gladly show her to any one desirous of seeing her, and have declared their intention of sending her to Ramsgate for trial early in November, as soon as stormy weather sets in.

The use of pontoons, or water-tight cylinders, for floating, is no novelty ; but this is the first time, as far as we are aware, that they have been combined and fitted, with sufficient skill and strength, as to form a life-raft. In January, 1813, Mr. THOMAS BOYCE, of Fetter-lane, was awarded a Silver Medal and 10 guineas by the Society of Arts, for a model of a safety-buoy, or small life-boat, consisting of two wooden cylinders, or pontoons, covered with water-proof cloth, connected together at 1 ft. apart, and bearing a grating between them; the cylinders were 1 ft. diameter, tapered and joined together at the end, and the whole only 3 ft. in width: it had a mast and sail secured above and below the grating, so that, which ever side fell uppermost, it was ready for use.

Pontoons for forming rafts and bridges for military purposes have been used since the time of Marlborough, and probably be- fore; but these were flat-bottomed boats.

The first use of the cylindric pontoon was proposed by Sir JAMES R. COLLETON, Major in the Royal Staff Corps, in a pamphlet published at Cambray in October, 1816 ; these were of wood, 22 ft. long, by 2 - ft. diameter, and the cylinders alone weighed 8 cwt. Colonel, now General, Sir CHARLES PASLEY also proposed a pontoon, shaped like a canoe, of a light timber frame, covered with sheet copper, and di- vided transversely into two equal parts for the facility of carriage; these were 2 ft. 8 in.

in diameter, and weighed 12 cwt. About the year 1820, Major, now Colonel, BLAN- SHARD, R.E., C.B., recommended cylindric pontoons of tin, of 2 ft. 6 in. diameter, but weighing only 7 cwt.; after a severe trial of the comparative merit of these pontoons in the Medway, in 1836, Colonel BLANSHARD'S were finally adopted, for military service.

A raft, 22 ft. long by 12 ft. wide, can be formed in a few minutes with these pontoons, and they can be rowed fast, and with great ease, in smooth water.

Among the numerous models sent to the Committee, in answer to the Duke of NORTHUMBERLAND'S offer of a premium for the best model of a life-boat, were 21 life- rafts; some supported by one cylinder, many more by two; some by closed canoes; some by a boat divided lengthways, and connected by a grating; some of wood; some of iron; some of gutta-percha: but none of them, apparently, combined and fitted with sufficient skill and strength to stand'the rough work to which a life-boat is liable.

The life-raft of RUSSELL and OSWALD, of Douglas, Isle of Man, which had been in actual use since the year 1850, and reported favourably on by pilots and others, appeared to the Committee one of the best, and it is described in p. 41 of the Appendix to their Report; others were by DOCKAR, of Banff, and SEVERN, of Buckingham Gate; but they gave no indication of any prospect of obtaining speed. A raft on cylinders, that was built of the full size, and tried before the Committee, could hardly stem the tide in the river.

The Messrs. RICHARDSON, however, have greatly improved on their model, and by the aid of a skilful mechanical engineer, have produced a life-raft which bids fair to com- pete, on advantageous terms, with any life- boat, and on a flat beach might prove very useful. . It may be feared that the iron of which the cylinders are formed will be liable to rapid decay, unless they can be well coated, inside as well as out, to preserve them from rust; but as the inventors have overcome greater difficulties, no doubt, this minor objection will be vanquished too; and we heartily wish them the success that their public spirit and perseverance have so fairly entitled them to.