THE

YEAR-BOOK OF FACTS.

Mechanical and Useful Arts.

HENSON'S AERIAL TRANSIT MACHINE.

THIS apparatus, which has been patented, has excited considerable attention, from its great apparent simplicity. It consists of a car, in which not only are the passengers to be placed, but likewise a steam engine, and the quantity of fuel necessary for such voyage; to this is attached a rectangular frame, formed either of wood or bamboo cane, covered over with oiled silk or with canvas; this frame is to supply the place of the balloon, and is, according to Mr. Henson's view, to be buoyed up by the action of the air; it will stretch out on either side of the car beneath, somewhat like the wings of the bird when sailing through the air. Two vertical fan-wheels, furnished with oblique vanes, which are to receive their propelling power from the steamengine in the car beneath, are to urge forward the whole apparatus ; at the stern of the car is the portion of the machinery destined to make the apparatus ascend or descend: it consists of a triangular frame, resembling the tail of a bird, covered over as the other frame: underneath this is placed a rudder, by whose action a course either to the right or to the left may be taken, besides which a sail is stretched between two masts, which are situated in the car itself. The buoyancy of all this machinery, under the circumstances proposed by Mr. Henson, is, we believe, impossible; the knowledge which has been gained of mechanics impresses us with a conviction that his views are fallacious. He thinks that an engine of from 25 to 30-horse power would be sufficient to propel his apparatus; but the amount of canvas or oiled silk required for its buoyancy, he states to be equal to one square foot for each half pound weight-the whole machine being about 3,000 lbs., and the area, or surface spread out to support it, 4,500 square feet in the two wings, and 1500 feet in the tail; making, altogether, 6,000 square feet. But he has taken no account of the fuel and water which are absolutely necessary for the action of his steam-engine. Now, the weight to be buoyed up, taking the apparatus at 3,000, would be 53,400 lbs. Instead of an engine of 30-horse power, one of 13,550 would be required. The machine is to be launched from a height, and allowed to run down some distance on an inclined plane, by means of vertical wheels attached to the bottom of the car; the momentum being acquired, the fan-wheels raise it into the air, and drive it forward; but if the weight be such as we have stated, a descending velocity would be acquired of 60 miles per hour, or 5,808 feet per minute-so that, for safety, it would at least be necessary to start from Mont Blanc, to give time for the rotatory fan-wheels to be set in motion.

目

Description.-A, A, the main frame, or wings, composed of longitudinal pieces, and bow-like frames across them.

B, B, B, B, &c., upright posts, or standards, to the upper and lower ends of which metallic braces, shown by the single lines, are attached, supporting various points in the frame.

C, C, a longitudinal piece, which forms the outer boundary of the space required for the vanes, or propellers.

D,D,D,&c., the vanes, or propellers, mounted on shafts, as shown in the figure, and drawn by steam-engines by means of bands.

E, E, &c., the tail, turning on a point at F. G, the car, containing the steam-engine, cargo, conductors, and passengers, in suitable compartments.

H, the rudder.

The covering of the wings and tail is of silk, or linen; that of the wings is divided into three lengths for each end, joining each other at the double frames shown. This division facilitates the rapid reefing and spreading of the covering, which is effected by the cords running parallel with the longitudinal pieces, of the wings. The tail and rudder are in like manner governed by cords proceeding from the car.

The novelty of the steam-engine lies chiefly in its boiler and condenser. The former consists of nearly fifty hollow truncated cones, averaging about three feet in length, and of four inches and a half in their greatest width: their blunted points, of about one inch in diameter, are downwards, and the whole are arranged above and about the fire; they present about fifty square feet to the action of radiating, and about as much more to that of communicative heat. The steam is worked in two cylinders, in which it is cut off at aquarter of the stroke. It is concluded the engine will be of nearly 20-horse power.

We need scarcely add, that Mr. Henson's contrivance is altogether out of the pale of the probability of success.

OPENING OF THE THAMES TUNNEL.

THIS stupendous work, as regards the passage beneath the Thames, was thrown open to the public as a thoroughfare for foot passengers, at a toll of one penny, on the 25th of March. The two roadways for carriages are also completed; but the Middlesex shaft and the approaches on each side remain to be perfected.

The Tunnel is now entirely completed, measuring 1200 feet. The entire work has been executed in about nine years of actual operation, at a cost of about £446,000; but it is estimated that when the Wapping shaft, approaches, &c., are perfected, the expense will be about £614,000. Seven lives have been lost in executing the Tunnel, whereas nearly forty men were killed in building the new London Bridge. As an exhibition, the Tunnel has been very attractive; the sum of £1,705 having been received from visitors, at 1s. each, in one year. Within five days from the opening, upwards of 60,000 persons passed through the Tunnel, at the toll of one penny each.

STEAM-ENGINE INDICATOR.

A SIMPLE Steam-engine Indicator has been invented by Mr. A. Rous, who was formerly a working engineer in Cornwall. It consists of a half-second pendulum, to which a pencil is fixed and pointed against a card. The card is attached to the beam of the engine, and as it moves perpendicularly the pencil on the pendulum marks on it waving lines, which are wide apart when the piston moves quickly, and closer together as the velocity of the piston decreases. The distances between the lines indicate the spaces moved through by the piston in half a second in different parts of the stroke.

MAMMOTH STEAM ENGINE.

An enormous cylinder of 144 inches diameter, for the great engine designed to drain the Haarlem Lake, has been cast at the foundry of Messrs. Harvey and Co. of Hayle; it is the largest cylinder ever cast entire for any purpose. A blast cylinder of 144 inches has, indeed, been constructed at the same works, but this was cast in parts. The largest cylinder ever made for mining purposes was of the diameter of ninety inches and a fraction. It was boasted, a few days since, that the cylinders for her Majesty's steam frigate, Penelope, were the largest ever made, being ninety-two inches in diameter. The cylinders of the Penelope, however, are only two-fifths the size of that cast at Hayle, the piston of one containing 6647 square inches, that of the other 16,286; the operation was completely successful. More than twenty-five tons of iron were melted for the occasion, and the whole of that mass of liquid fire ran out into the mould in less than six minutes: not a single casualty occurred. The ironfounders of Hayle may now justly boast that they have executed by far the greatest work in their line which has ever been attempted.-Mining Journal.

VELOCITY OF STEAM-ENGINES.

PROF. MOSELEY'S Report of Experiments on Steam-engines, with Morin's instrument for measuring Velocities, has been read to the British Association.* The experiments have not been completed, and the present communication was rather to report progress than to state results. The object had been to ascertain, by actual experiment, the velocity of the piston of a single-acting Cornish pumping-engine at all points of its stroke. Morin's velocity-measuring machine was received from Paris, and by it spaces described in the 20,000th part of a second may be easily discerned. It describes a curve somewhat resembling the epicycloid, and from this curve the velocities are ascertained. The principle of the indicator, by which the experiments were made, is this: a circular disc of cardboard is made to revolve on a fixed axis, and a revolving pencil connected with the piston, describes the indicating curves. The disc which was sent as a specimen indicated the result of experiments made at the Cornish engine at Old Ford. The results were, that the piston of the engine of Old Ford, on the day of experiment, acquired its maximum velocity of ten feet a second, at four feet of stroke, and from that point the velocity gradually diminished, until the piston was brought to rest.

NEW PLAN OF STEAM-BOAT BOILER.

A NEW variety of Steam-boat Boiler has, during the last year or two, been gradually coming into use in the steamers on the Thames. It is now being extended to sea-going vessels, and it is not too much to expect from its introduction a complete revolution in the art of navigation by steam.

The variety of boiler to which we allude is of the locomotive kind, that is, the flues consist of locomotive tubes, the furnaces being arranged much in the way usual for marine boilers. The boilers, however, are much stronger than usual, the shell and furnaces being of extra thick plate, and the sides and ends are very firmly stayed.

The purpose of this plan of boiler is to enable marine engines to be wrought with a higher pressure of steam than at present, without additional danger; and thereby render practicable the full development of the expansive system. A great saving in fuel will thus be accomplished, as well as a large amount of boiler room. Indeed, boilers of the same power, on this new construction, will not take up more than half the room occupied on the former plan.

It is to Messrs. Miller and Ravenhill, we believe, the introduction of this new variety of boiler is due. The boilers of the Blackwall, Prince of Wales, and other vessels, constructed by Messrs. Miller and Ravenhill, are of this description; and the same makers are now constructing a set of these boilers for the Infernal, a new Government steamer, now being fitted with engines.-The Artizan, No. 8.

*The Association met at Cork, August 16, 23; the Earl of Rosse, President.

NEW STEAM-VESSELS.

ANNEXED are the most important novelties of the year, of this class:

Her Majesty's Royal Steam Yacht Victoria and Albert.-The launch of this singularly beautiful and magnificent steam vessel took place at Pembroke, on the 26th April. The following are the principal dimensions:-Extreme length, 225 feet; length on the deck, 205 feet; length between perpendiculars, 200 feet; length of keel for tonnage, 181 feet 2 inches; breadth outside paddle boxes, 59 feet; breadth for tonnage, 33 feet; breadth moulded, 31 feet 11 inches; depth in hold, 22 feet; burthen in tons, 1,049. She is divided into five water-tight compartments, and her engines, by Maudslays and Field, are of 450-horse power. Her construction is entirely novel, and according to designs prepared by the Surveyor of the Navy. She is considered by competent judges to be superior in point of beauty, buoyancy, and strength, to any other description of steam vessel ever produced in this country. She is built only with plank; the first two layers being of oak 13 inches thick, placed across each other diagonally at an angle of 45 degrees; the outside plank being of larch 3 inches thick, lying longitudinally or with the sheer of the ship; and the whole being bound up with vertical and diagonal iron bands. Between each layer of plank, the surface is covered with thick tarred felt; the vessel therefore cannot leak, nor be in the least degree damp inside; and being divided into five compartments by four water-tight bulkheads extending as high as the state deck, it is impossible for the body ever to sink, although it might be bilged in any part from accident. Her engines are collectively of 400-horse power; they are upon the direct action-principle, with double cylinders, as patented by Joseph Maudslay and Joshua Field. They have brine or change pumps, to prevent the deposit of salt when using sea water, refrigerators to cool the water by extracting the heat from it before it goes overboard, expansion gear by which the steam can be used more economically; but the boilers produce an ample quantity for full speed without this resource. The engines are compact, and occupy but a very small space in the vessel, compared with their great power to move paddlewheels 10 feet 6 inches broad, and 31 feet diameter, including the feathering boards. The engine-room is surrounded by water-tight bulkheads, not the least heat is communicated from the furnaces to any other part of the vessel, and their presence is not perceptible in the rooms adjoining them.

The Steam Frigate Rattler.-This is a vessel to which Mr. Smith's screw is adapted, and was built in Sheerness dock-yard. The following are some of the principal dimensions:-Extreme length, 195 feet; length on the deck, 176 feet 6 inches; length of the keel for tonnage, 157 feet 9 inches; extreme breadth, 32 feet 8 inches; breadth moulded, 31 feet 10 inches; depth in hold, 18 feet 7 inches; burden in tons 888 and 34-94ths. The engines are by Messrs. Maudslay. The gearing by which the screw is driven nas been made with great care and nicety. The teeth of the main wheels are divided into three steps; that is, they are cut in the direction of their length into three portions, each of which is placed a little before the other; the pitch being thus virtually divided into three parts. By this expedient, a great equability will be given to the action of the gearing, and we anticipate that it will work with very little noise.

The Great Britain, of which the leading details were given in the Year Book of Facts, 1843, was launched at Bristol, on the 19th of July, in the presence of H. R. H. Prince Albert. This stupendous vessel has not, however, been yet completed.

The Novelty, built by Wimshurst, is an iron vessel, to test the applicability of steam in combination with a screw, as an auxiliary power to merchantships. She is three-masted, with a capacious hold; and, as her funnel forms the mizen-mast, and as she is, of course, without paddle-boxes, she differs in no respect, in external appearance, from an ordinary sailing vessel. She is fitted with a pair of non-condensing engines; the cylinders are 13 inches diameter, and the length of the stroke 2 feet 4 inches; the effective force of the steam on the piston is stated at 20 lb. mean pressure. The engines make