The advantages of this arrangement are, that the lanterns can be made. much lighter; that the rolling of the vessel, caused by so great a weight at the mast-head, is greatly diminished; and the machinery, being more under control, and better protected, works with greater regularity and precision. In the opinion of experienced persons, these improvements are most important, and the uninitiated may form an idea of their utility by reflecting upon the situations in which the light vessels are placed; and also that these vessels are at all times difficult of access, and in stormy weather, when accidents are most likely to occur, quite unapproachable; so that it will be obvious any alteration which reduces the liability to derangement is greatly to be appreciated.

There is also a vast benefit derived from the novel construction of the lamps and jumble work, which, by a movement exactly coinciding with the motion of the vessel, causes a perfect level to be always maintained, and insures the proper flow of oil to burners, however irregular that motion may be. This improvement is not of so recent introduction as the former; but when it was first invented, it produced a complete revolution in the apparatus used for floating lights, and enabled the beautiful argand lamp, with parabolic reflectors, to be used instead of the old lamps with flat wicks.

There are 108 light-houses on the English coast, 51 of which are for ports or harbors.

There are also 18 floating-lights; including Scotland and Ireland, there are 219 light-houses, most of which are under the control of the Trinity House.

They collect £240,000, and cost £97,000.

Model of Liverpool Docks.

This model is undoubtedly one of the most interesting objects of the kind in the Exhibition. It originated in a desire, on the part of some of the leading inhabitants of Liverpool, that this great port, the outlet of so large a portion of the commerce of Great Britain, should be fairly represented in the display of all nations. The idea has been admirably carried out by Mr. J. Grantham. The model is 40 feet in length, 10 feet wide, and on the scale of eight feet to a mile, and represents a surface of five miles. The docks are represented as being filled with 1,600 small vessels, fully rigged; and, altogether, the model forms a very beautiful object, impressing the inspector with the magnitude of Liverpool as a port.

The model is chiefly cut out of wood, the finer portions being con. structed of paper, and the water represented by glass, stained of a greenish tint, and silvered, in order to reflect the ships which float on its surface. Its cost is stated to be £750. It is supported on an appropriately designed base, formed of elephants, cast in iron, from the back of which the columns which support the roof arise; pediments filled with appropriate decorations, in imitation of bas-relief, being at the end and centre. This model is strikingly calculated to display the advantage of this most important commercial town, of which some idea may be formed from the following statistics: In the year 1650, it is said, there were only three ships belonging to the port. In 1816 there were 6,888 entered the docks, of 774,243 tons burden, and paying, in dock dues, £92,500. In

1850 there were 20,457 vessels entered, of 3,500,000 tons burden, and paying £211.000 dock dues. There are 21 docks, 2 half-tide docks, 8 graving docks, and 4 basins, capable of containing 1,500 sail. The annual income of the docks is about £300,000, and the charge about £280,000. The receipts of custom duties, in 1850, amounted to £3,366,284. Liverpool imports eight-ninths of all cotton shipped to Great Britain. As many as 50,000 hogsheads of sugar, 20,000 barrels and bags of coffee, and 10,000 puncheons of rum, have been brought to Liverpool in one year. As one among numberless illustrations which might be given of the extent of Liverpool commerce, it has been stated that 27,000 cubic feet of logs of cedar, for making lead-pencils, have been in the docks at one time.

Out of the remaining numerous objects well worthy of careful inspection, we can only briefly enumerate a few of the most striking The model of a self-supporting suspension bridge, invented by Captain Kenezynski, presented the means of building a wooden bridge without any support from centring. If it be a bridge of one arch, for example, short iron chains, or bars of iron, are fixed in the mattresses on each side, to be used as supports for the first timbers of the arch. As the work proceeds, other and larger bars are attached, to act as a scaffold for the next timbers; and in this manner the work is advanced from each side until the key block of wood can be inserted, and the arch can support itself. The suspension bars are retained as additional supports, and, by means of screws and nuts, may be lengthened or shortened, to increase or diminish the strain upon them.

The model of a bridge of a very new kind is exhibited by Mr. Bain, of Greenwich. It is intended to cross a river, without offering hindrance to ships of any size. The road-way is enclosed in a large tube, to be let down under the bed of the river, like an inserted arch. This tubular bridge under water is to be lighted by apertures in the upper por. tion until the water-mark is reached, and if the curve be not very great, the light admitted on both sides might penetrate sufficiently to the bottom.

Another curiosity in the plans proposed for crossing rivers was exhibited in a rough model of a portable bridge across the river Avon, at Clifton. The suspension bridge from cliff to cliff having been abandoned, for want of funds, it is proposed to have a platform elevated from a truck, moving on rails, in the bed of the river.

A model of the landing machine for the floating railway ferry to the Edinburgh and Dundee railway exhibited the curious contrivance adopted for shipping and unshipping railway carriages. The steam ferry boat has rails fore and aft, on which the van containing the luggage and heavy goods is shipped, to be carried across the Frith of Forth. The landing machine, in appearance, resembles a draw-bridge; one end of it is lowered into the fore-part of the ferry boat, and fixed to it so that the nails on both may coincide. The carriages are then allowed to run down - singly into the boat, their speed being retarded by means of a rope. In unshipping the train, the rope is used to drag the carriage up the incline, which, at low tide, is very steep.

The commissioners of northern light-houses exhibited a model of the Skerryvose light-house, which has been built in recent years, under circumstances of immense difficulty. Mr. Allan Stephenson undertook the

work in 1834, but it was not until ten years afterwards that the lights were exhibited. The rock is twelve miles from a small island called Tinee, and Tinee is two or three days' sail from any part of the coast whence supplies could be obtained; hence the difficulties encountered by the engineers and workmen were most harassing. It was at all times difficult to approach the rock, and when there, the number of working days in a year was very small. The rock itself is excessively hard, and the difficulty great of transporting stones thither. But all difficulties gradually gave way to the skill and perseverance of the engineer, and the structure was at length completed. It is 138 feet high, curving inwards from a basis of 42 feet. It contains nine stories, or apartments, in height. More than 4,000 tons of materials were used in its construction. The lighting apparatus consists of eight annular lenses, revolving round a lamp of four centric wicks, and producing every minute a bright blaze, visible at a distance of 18 miles.

There were some models of gas apparatus and gas metres; but the exhibition of gas apparatus was very limited, on account of all fire and light being prohibited in the building This very necessary regulation had the effect of inducing most of the manufacturers of gas burners, and other gas apparatus, to decline exhibiting.

Near to the gas apparatus was a ventilating pump, worked by a weight, and producing a copious stream of air, at a moderate velocity, suitable for the ventilation of private houses.

One of the most unique models of its kind, and which was an object of deserved admiration, was that of the Under-cliff, Isle of Wight, by Captain Ibbetson. It is the only model of a large extent of country on an equal scale, the vertical height and base being on the same scale; and it is also probably the only model that has been entirely worked out of doors. We understand that it was carried into every corner of a field or court, and modelled on the spot, and that there has been more than 60,000 heights measured trigonometrically, and all correspond with the base. The geological strata on the cliffs have also been measured trigonometrically. The entire labor occupied upwards of five years, and altogether reflects the very highest credit upon the ingenuity and perseverance of Mr. Ibbetson.

Naval Architecture, Military Engineering, Ordnance, Armor, and Accoutrements.

In this class were included models of ship-building, for the purposes of commerce and war, for the application of steam and other powers, and also of vessels used for amusement, and small vessels generally; rigging, anchors, windlasses, and articles connected with practical seamanship, and the saving of life from shipwrecks; infantry and cavalry arms, clothing and accoutrements, camp equipages, naval gunnery, and weapons of attack and defence; artillery equipments both in garrison and in the field; machines for mounting and dismour.ting ordnance carriages, &c.; ordnance and projectiles, small arms-such as rifles, muskets, carbines, pistols, &c.; and, lastly, military engineering, field equipments, methods of passing rivers and other obstacles; the attack and defence of fortresses, and field fortifications.

The models of vessels were exceedingly numerous, and were most of them remarkable for their delicacy and finish. A steamer exhibited by J. Clarke, of Birkenhead, was amongst the most attractive objects in this class. The whole was remarkably well proportioned, and was fitted up in the most complete manner, exhibiting all the latest improvements introduced in steamers of the larger class. This model merited the attention of those acquainted with naval architecture, as it was rigged in the most perfect manner, both as regards the materials and style. The hull, which is also very neatly finished, is also of a good mould, and suitable for speed and stowage. This vessel seems well calculated to possess all the qualities desirable in a good sea-boat, and for carrying weight at an increased speed.

Model of Life-Boat.-By Mr. Dyne, London.

The object of this invention is to render ordinary ships' boats so buoyant that they virtually become life boats, and are capable of saving the crew and passengers under almost any circumstances. The material employed is naturally extremely buoyant, and by the process to which it is subjected is rendered impermeable to moisture. By filling the spaces between the timbers and beneath the thwarts with this material, previously made up into properly proportioned packages, and then covering the whole with a thin lining of board, a boat is rendered so buoyant that, even when overloaded with passengers, should the waves break over it, there would be no risk of its sinking; or should even the bottom be stove in, the frame would float and act as a raft, which the material, from its tenacity and fibrous nature, would hold together. The specific gravity of the material is so very small that the additional weight to the boats is scarcely felt on hoisting them on board, and no injury can be caused by driving nails, or by blows, as is the case with metallic or cloth air-tubes, &c. The process can also be advantageously applied to the bulwarks, and between the timbers and ceilings of ships; and it must be evident that in the event of their going to pieces, each portion would, from its power of flotation, become a life-buoy. It should be remarked that the material can be adapted in any bulk, in any form, and to any part of the ship or boat usually left vacant; and, consequently, that it will not diminish the space for stowing the cargo, and that the mattresses, couches, seats, and all the furniture, could be rendered subservient to saving life. It may likewise be applied to jackets, belts, life-buoys of all kinds, and floats for fishermen. The life belts are unequalled in lightness, can be adjusted in ten seconds, and are incapable of being injured by puncture or climate.

Mr. W. Dyne, of London, exhibited a life boat formed of diagonal battens, laid similar to that of lattice-work-its outer sheathing being formed of gutta percha; its buoyancy is 350 cubic feet of air, capable of sustaining upwards of nine and a half tons. It has in its bottom 3,600 holes, half an inch in diameter, to allow all water supplied to pass off. It has a convexed bottom, thirty feet long, two feet wide, and eighteen inches deep, in which are placed three perforated fins for the purpose of steadying and keeping the boat in an upright position, acting, when the boat lurches from either beam, similar to a paddle wheel, a reaction taking place, through the perforated parts, which will be seen to multi

ply its weight of water to four times its amount. In this convexed part, and between the fins, are contained two tons weight of water which must be displaced therefrom before the boat can turn over; but such will be almost impossible, it being more than half the weight of the boat. As a provision against such a disaster, she turns over on her quarter sixteen hundred weight of water, which rights her again. It may be remarked that the two tons and sixteen hundred weight of water referred to are not one ounce weight to the boat when in her upright position. At the stem and stern, and on each beam and quarter, is run a bow, to which are connected galvanized springs, which will not corrode, and which will be found of the greatest utility in the event of collision-which act similar to railway buffers, and enable a stranded vessel to communicate with the shore. It is intended to be placed at the stern of the ship, so that on any alarm being given of "a man overboard," the person at the helm can dislodge it instantly, and, as it falls into the sea, a fusee becomes ignited, which burns with a brilliant light, guiding the sinking man to it. Should the accident occur at night, four uprights are placed upon it, containing rockets, blue and other lights, to be kept burning and shot off.

The same person also exhibited an emigration life boat, intended for a first-class vessel, of the following dimensions: 20 feet long, by 14 feet wide; it is united by strong bolts, and is very portable from the mode of its construction, which allows it to be folded into the compass of 20 feet long, by two feet six inches wide. On occasion of shipwreck, it is capable of supporting 100 persons, with provisions, for seven days; in addition to which, it may be made available for a portion of the cargo, and can be put in requisition in a few minutes.

The Duke of Northumberland had recently offered a prize of £100 for the invention of the most efficient form of life-boat, and this offer led to the exercise of much ingenuity on the subject. No less than 54 models competing for the prize were exhibited, of which we can only notice two or three.

The first thing to be provided against in a life-boat is its liability to capsize in a heavy sea. One mode of remedying this evil is so to construct the boat that it may right itself immediately after being upset. To effect this, it is necessary that the boat should be of a very peculiar shape, which may probably not adapt it so well for going through the water, and that it should be heavily weighted along the keel, giving it a deep draught of water, which renders it difficult to pull, and to get rid of the water when swamped, as a boat so deep in the water is peculiarly liable to be.

In most of the models exhibited, the total width is eleven feet; and we imagine it will be exceedingly difficult to launch them in a strong breeze, when blowing into the coast from which they are to set out. Moreover, these boats are liable to turn over, though they will right again. Prevention is better than cure; and it is, therefore, manifest that a boat which cannot upset is better than one that will upset and right itself, half-drowning and knocking about the persons on board, and washing away those who are unfortunately not lashed. If, in order to prevent upsetting, the breadth of beam be greatly increased, it offers too much resistance to wind and water, especially on moving against a gale. A double-bodied boat, consisting of two boats held apart by a