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MISCELLANEOUS.

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Improvement of Light-houses.-It has been suggested that light-houses might be improved," by adding one or more lights below the large light; for example, one at fifty feet below it, and another at one hundred feet below it. The object of this addition would be to enable an observer at sea to determine the distance of his vessel from the light-house. So long as the first of the lights below-the great light is below the horizon, the distance may be concluded to be considerable; and when it can be seen, there being a known distance between the two lights, the distance of the vessel may be easily computed, if the angle subtended by the two lights be measured. Every proposal for the improveinent of light-houses ought to be examined, in consequence of the importance of these buildings. to a commercial country such as our's. The present suggestion, though good, is perhaps not of a nature to be adopted in practice without involving some difficulty, for the lower light ought to be seen in every direction, and in the same vertical line as the upper oue. These conditions are not easily obtained. Perhaps the best mode would be to make the lower light. revolve round the light-house. And it is essential that the lower light should be as distinct as the upper one, otherwise it might occasion serious errors in hazy weather.

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Double Steam-boat of Iron.-A steam-boat has just been built at Liverpool, for the canal be.. tween Limerick and Dublin, which is made entirely of iron, and is of a very peculiar construction. When seen out of the water it has exactly the appearance of two vessels joined together by the deck, but separated in every other respect. The paddles, instead of being at the sides, are placed in the middle between the vessels, so that in working they will not injure the banks of the canal, which has hitherto been the principal obstacle to steam-boats being em ployed in canal navigation.

Method of Separating the Fibre from the Seeds of Cotton Windmills are erected in Barbadoes to clear cotton from its seeds. The cotton, when pulled from the pod, envelopes the seeds, and forms a covering for them. To separate it, they cause it to pass between two small metallic rollers placed horizontally one over the other, and turned by the windmill. These lie so close" on each other, that they will only permit the wool to pass, which falls into a box on the opposite side, while the seeds fall in front of the collers.

To correct Damaged Grain-Musty grain, totally unfit for use, and which can scarcely be ground, may, it is said, be rendered perfectly sweet and sound by simply immersing it in boiling water and letting it remain till the water becomes cold. The quantity of water must be double that of the corn to be purified. The musty quality rarely penetrates through the husk of the wheat, and in the very worst cases it does not extend through the amy-laceous matter which lies immediately under the skin. In the hot water all the decayed or rotten grain swims on the surface, so that the remaining wheat is. effectually cleansed from all impurities, without any material loss. It is afterwards to be dried, stirring occasionally, on the kiln.

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Migration of Eels. Upon the head of Benmore, one of the promontories near the Giant's Causeway, in Ulster, are two small pools or lochs, from which a small stream trickles over the rocks into the sea. Up this steep channel young eels, not thicker than small pack-thread, ascend to the lochs, where they thrive exceedinly. This migration is so regular all along be coast, that the peasantry at the proper season

lay hay-bands down the rocks to assist the progress of the young brood, from which a rich supply of food is anticipated when the eels are full grown, eels being a great favourite in the north of Ireland.

The Manita Tree, so named from the resemblance of its flower to a little hand, (manita) is: a species of plant almost unknown in the catalogues of botanists. It is sometimes supposed that only three specimens are in existence; two' in the small botanical garden at the palace of the city of Mexico, and one at the town of Toluca, It is certain nobody in Mexico can tell whence they originally came, or where they may be found growing in a wild state; but as they were preserved with many other foreign productions by the emperor Montezuma, it is imagined either himself or ancestors must have obtained them, from the interior of South America. The tree is about forty feet high, with a smooth trunk, without branches almost to the top; but the Loughs then stretch over a considerable distance, with large leaves and numerous flowers hanging downwards from amongst the foliage. It bears a stronger resemblance to the plane or the tuliptree, than any others we are acquainted with in Britain. Two of this species were found by the Spaniards at the time of their conquest, and form a solitary exception to the devastations of those adventurers; most probably because Cortez occupied the site of the palace for his owu residence, and therefore coveted the shade of its garden; the smaller plant now growing at Mexico is considered to have been a sucker from the other. Tradition states, that though they Indians did not actually worship the manita tree, yet they regarded the flower with a sort of religious veneration.→→Merican Illustrations.

INTERIM, NOTICES.

We regret that the engraving of Mr. Saddington's new sliding Rule has not been finished by the promised time to ebable us this week to present to our readers his valuable communication; it will positively appear in the next number.

Communications received from N. V. S. T.-G. P. W.-A Constant Reader.-S. `R.P. M.-J. D. R.-An original Supporter.-. W. BT. K.-X.-G. A. E.-Omicron.

ERRATA.

have exchanged places with that near The wood-cut, bottom of p. 53, should the top of p. 54.

P. 55, col. 2, 1. 1, for "AB 4 D," read, "ABCD."

Ibid. col. 2, 1. 2, for "D4," read "D C."

- Ibid. 5th line from the end of the article by G. S. for 104-7197126+12,' read" 104.7197126 × 12."

P. 96, col. 2, 1. 20, for 64 read compression.'

"

absorption,"

LONDON: Published for the Proprietor, by -M. SALMON, at the Mechanics Magazine Office, No. 115, Fleet Street; where Communications for the Editor (post paid) ace requested to be addressed.

M. SALMÓN, Printer, Fleet Street.

Sir,-After showing the following plan to some learned gentlemen, and mechanics, they generally allowed, that there was no doubt of a machine of this kind answering effectually. I take the liberty, therefore, of transmitting it to you, in the hope that you will give it a place in the Mechanics' Magazine.

Description.

A (see prefixed engraving) is a working beam the same as in the steam-engine, B the frame that supports it, C a pump, D a cylinder, E the piston, bb two pairs of bellows, cc valves by which the air is sucked into the bellows, dd valves that discharge it. Now, the bellows being made to contain a little more air than the one half of the cylinder, when the crank G lifts the bellows, the bellows suck the air out of the bottom of the cylinder, and the piston comes down, by the air acting upon it through a valve m at the top of the cylinder. Likewise when the upper crank G lifts the upper bellows, it sucks the air out of the upper part of the cylinder, and the piston ascends upwards by the air acting upon it through the valve at the bottom of the cylinder at n; the valves upon the bellows at c and d, are placed so, that when the one opens the other closes, which the action of the air in the bellows does itself. Likewise the valves upon the cylinder m and n must be made to open and close from the action of lifting the upper parts of the bellows, to give the air free access to act upon the piston; NNO are the horse gears, which put the whole machine in motion. Some of the individuals to whom I have shown this plan have thought that one-horse power could not work the bellows. My opinion 7 however is, that as the air comes free Ento the bellows, and goes as freely out, that it may be done with a horse or two, because it is well known, that it is not the air coming into the belLows that would cause the great draught upon a horse, but the forcing the air out through a small tube for blowing a fire. Could any ingenious

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mechanic bring a machine of this kind to perfection, it would be a general service to all parts where coal or water is not easily got

I am, &c.

H. OGLE, Schoolmaster, Rennington by Alnwick, Northumberland.

May 20, 1829.

GRAND MECHANICAL COMPETITIONRAIL-ROAD RACE FOR £500. 3 The great rail-road between Li verpool and Manchester being now nearly completed, the directors of the undertaking sometime ago announced that they would give a premium of £500. for the locomotive engine, which should, at a public trial to be made on the 1st of the present month of October, (afterwards postponed to the 6th) draw on the railway a given weight with the greatest speed at the least expence. The offer of so handsome a premium, and the brilliant professional prospects which the winning of it presented to mechanical men, naturally exerted a very lively spirit of competition among them. In almost every quarter of the country, engine makers and engine inventors set themselves to work to secure the prize, and the result, we are happy to say, has been such as to furnish a lasting example of the wisdom of calling into action, and giving fair play to the general talent of a country, when any great public object has, as in the present instance, to be accomplished.

At all hands, the directors of the Liverpool and Manchester railway, deserve thanks for their conduct on this occasion, from their constituents, for the good sense and liberality which dictated a competition by which the capability of the railway, to do all that was promised, and much more, has been at once placed beyond all doubt, and the chances of a profitable return for the money invested in it increased at least tenfold; from the owners of the competing engines, for the liberal encouragement by which they were induced to start for the plate, and the impartial spirit, (divested of all local and personal in

fluences) in which the competition has been conducted, and from the nation at large, for the powerful im pulse which this demonstration of the extraordinary celerity with which carriages may be propelled on railways, must give to the more extensive adoption of this mode of conveyance throughout the kingdom.

The principal conditions on which the prize was offered were these:1st. That each engine entered for the competition should weigh not more than six tons, and be capable of drawing after it, day by day, on a level plain, a train of carriages of a gross weight, equal to three times the weight of the engine itself, at a rate of not less than ten miles per hour, with a pressure of steam in the boiler not exceding 50lb. on the square inch. 2. That the engine and boiler should be supported on springs, and rest on six wheels, and the height from the ground to the top of the chimney should not exceed 15 feet. 3. That the engine should "effectually consume its own smoke;" and 4. That there should be two safety-valves, one of which should be completely out of the reach of the engine-man's interference.

The gentlemen appointed by the directors to act as judges on the occasion, were J. U. Rastrick, Esq., of Stourbridge, civil engineer, Nicholas Wood, Esq., of Killingworth, civil engineer, (author of the excellent work on railways) and John Kennedy, Esq., of Manchester.

The portion of the railway chosen for the running ground" was on the Manchester side of Rainhill Bridge, (about nine miles from Liverpool) where the railway runs for two or three miles on a dead level.

Early on Tuesday, the day of competition, great crowds of people were assembled from all parts, to witness the sight. There were many individuals who had come hundreds of miles for no other purpose; and, as may readily be supposed, these were not idle spectacle hunters, but chiefly engineers and men of science capable of appreciating, in its full extent, the great importance of the exhibition.

The number of competitors was at first reported to be ten, and we have

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reason to know there was at least as many engines as this in preparation. In this new sort of race, however, as in others, there were some withdrawn, and some prevented by accidents from making their appearance; and the number was reduced on the morning of trial, to five, who were thus described in the official list of the running coaches:

No. 1. Messrs. Braithwaite and Erickson, of London; "The Novelty;" copper and blue; weight, 2 tons 15 cwt.

2. Mr. Ackworth, of Darlington; "The Sans Pareil;" green, yellow, and black; weight, 4 tons, 8 cwt. 2 qrs.

3. Mr. Robert Stephenson, Newcastle-upon-Tyne; "The Rocket;" yellow and black; white chimney; weight, 4 tons, 3 cwt.

4. Mr. Brandreth, of Liverpool; "The Cycloped;" weight, 3 tons; worked by a horse.

5. Mr. Burstall, Edinburgh; "The Perseverance;" red wheels; weight, 2 tons, 17 cwt.

The engine which made the first trial, was the "Rocket" of Mr. Robert Stephenson (the son, we believe, of Mr. George Stephenson, the engineer of the railway.) It is a large and strongly-built engine, and went with a velocity, which, as long as the spectators had nothing to contrast it with, they thought surprising enough. It drew a weight of twelve tons, nine cwt. at the rate of ten miles four chains in an hour, (just exceeding the stipulated maximum,) and, when the weight was detached from it, went at a speed of about eighteen miles an hour. The faults most perceptible in this engine, were a great inequality in its velocity, and a very partial fulfilment of the condition that it should "effectually consume its own smoke."

The next engine that exhibited its powers was "The Novelty" of Messrs. Braithwaite and Erickson. The great lightness of this engine, (it is about one half lighter than Mr. Stephenson's) its compactness, and its heautiful workmanship, excited universal admiration; a sentiment speedily changed int perfect wonder, by its truly marvelous performances.

It