upon this tube the entrail to be stuffed is gathered in the usual way.

To allow the escape of air, this latter tube has a small tube, or opening, soldered on its outside, from end to end. This opening may be semicircular, so as to make but a slight projection on the stuffing-tube. The effect of this will be obvious.

We have not thought it requisite to give the dimensions of the respective parts, as they will vary according to convenience, and will depend upon the power to be applied, and the quantity to be cut. One thing, however, is essential, namely, that the length and size of the cylinders, and the number of knives, be proportioned to the quantity to be cut; but this can be regulated also by the pressure made upon the piston.

APPARATUS FOR HOISTING AND DELIVERING BURTHENS FROM SHIPS, Barnabus Pike, New York.-A frame is to be made by connecting two stout pieces of timber, sixteen or twenty feet long, by cross timber mortised into their ends. The long timbers for a railway upon which to support a carriage, which runs upon friction-rollers on their upper edges. Stout legs are framed into the lower sides of the rail timbers, the carriage has a block and tackle attached to it, by the aid of which, and a windlass, the goods are to be raised from the hold of a ves. sel. The carriage is then moved along the rails, which extend on to a wharf, and the packages landed. The claim is to the carriage as above described and applied, and the principle and mode of carrying and delivering the burthens.

The whole is clearly described and represented, and at certain periods we have no doubt that such an apparatus will be very useful; but the rise and fall of the tide must, in most places, very much interfere with the employment of it.

XYLOGRAPHIC CHECK PLATES, Charles C. Wright, New York. The plate from which notes, or checks, are to be printed is to be covered, by means of an engraving-lathe, by transferring, or otherwise, with a very light pattern, consisting of close, but fine, lines. From this the paper is to be printed, say of a light blue, pink, &c. The standing words may then be printed of another colour by any of the known methods. Should chemical means be resorted to for the removal of the fine ground, no human ingenuity, it is said, will suffice to restore and re-unite the lines; and to transfer the two kinds of printing lithographically will be equally impracticable. When used without the printing of standing words, any erasure on the fine ground will be perfectly apparent.

The invention consists in the prepared ground covering of paper to be used for secu

rities written in whole or in part, with or without standing words in the same, of different colour from such ground, substantially as above described."

EVER-POINTED PENCIL CASES, Ellwood Mears, Philadelphia.-The improvement consists in the manner of forcing the lead out of the metal point, and is as follows:The slide or band, which moves up and down the stick, is also capable of a circular motion around it. This slide, or band, has on its inner surface a screw thread, into which the nut of the pin, or wire, used in propelling the lead from the point, works. The band or slide is kept in its place, and pushes out. this metallic point by means of two small screws fastened to the lead groove within the case, and rising on each end of the band. Thus by holding the case in one hand and turning the slide or band to the left, or, if preferred, by retaining the slide so as to be immovable, and turning the case to the right, the lead can easily and quickly be propelled from the metallic point.

"What I claim as my own invention, is the method of using the band, or slide, in forcing the lead out of the metal point, instead of the complicated works heretofore in use."

MACHINE FOR FELLING TREES, James Hamilton, New York.-The patentee, after, describing the construction of his machine, says, "this applicant in the next place.describes the principle of his invention, as follows:-It consists of the combination of a horizontal saw with a crank movement, the saw being of any convenient length, but in the shape of a small segment of a circle, and the length of the crank with which it is directly connected being sufficient for the length of the intended stroke of the saw, the saw being fixed in a frame, and this moving in a centre fixed in another moveable frame which is connected with and moveable upon the same centre as that of the crank; this frame having a horizontal circular movement upon a roller, by force of a weight acting over a pulley, so as to bear the saw forcibly against the material to be sawed, the crank being made to act by any convenient mechanical motion, the whole operating so as to saw horizontally, it being designed for felling trees by sawing through the trunk of a tree horizontally, and near the ground.”

Mechanical saws of this description have their uses, as for cutting off piles under water, &c., but they will never enter into competition with the axe of the American woodman; and we are well convinced that in an attempt to use them in this way, his aid would not unfrequently be required to extricate the saw from the kerf in which it would become pinched.

NOTES AND NOTICES. House-Fly Guard.-At the Entomological Society, on Monday, a paper was read by the secretary on excluding the house-fly. The mode adopted was a net made of different coloured meshes of about three-quarters of an inch square, and which, when placed against a window, was found quite effectual in excluding the visits of these troublesome insects from the outside of the room. The same experiment was tried with meshes made of the finest black thread, one inch and a quarter square, which proved to be equally effectual. The approach of wasps was also prevented by the above mode, very few finding their way within the boundary. This was accounted for by an optical illusion in the eyes of the insect, of the highly magnifying power of vision, and the small focal length.

Expensive Tables.-Tables of tiger and pantherwood (different varieties of the citrus) appear to have been first brought into fashion by Cicero, who is said to have given for a single one a million sesterces, i.e. 80721. One belonged to Gallus Asinius, which was valued at 88791. Two, which had formerly belonged to King Juba, were actually sold, one for 97007., and the other for somewhat less. Another, which had been for some generations in the family of the Cethegi, was sold for 11,3007., and in the time of Pliny was accidentally destroyed by fire. The largest ever known belonged to Ptolemy, king of Mauritania: it was four feet and a half in diameter, and four inches thick, being formed of two semicircular planks, so skilfully joined that the place of juncture was not discernible. These tables were generally set in a broad border of ivory.-Mr. Aitken- Trans. Soc. of Arts.

Heat.-At a meeting of the Philosophical Society, Mr. Whewell gave an account of the recent discoveries made by Professor Forbes, and other philosophers, with respect to the polarisation of heat. He sated, that Professor Forbes had recently obtained an additional confirmation of this discovery, by finding that heat, by two internal reflections in a rhomb of rock-salt, resembling Fresnel's rhomb, becomes circularly polarised under the same circumstances as light. It was also mentioned that Biot and Melloni have very recently ascertained that heat acquires circular polarisation by transmission along the axis of a crystal of quartz.-Cambridge Chronicle.

The Danube.-Austria, reflecting that the Da nube, the largest river of Western Europe, flows for the greater part of its course through her dominions, and is also her own way to Byzantium, has determined to encourage upon it a line of steamboats. This, in the form of a measure of industry, amounts to a protest against the invasion of the mouths of the river by Russia. There is to be one grand line from Vienna to Smyrna, by Constantinople; and another from Vienna to Trebizonde. The service from Presburg to Smyrna commenced on February 18th, and will employ seven namely, three on the Upper Danube, between Presburg and Drcichora; two on the Lower Danube, between Slela-Cladova, Galatz. and Hirsova; one from Hirsova to Constantinople; and one from Con stantinople to Symina.

boats,'

M. Brunel's Mode of Constructing Arches without Centring:-Institute of British Architects, 14th March. The secretary read a paper explanatory of M. Brunel's mode of constructing brick arches without centring; and a'so explained various experiments of that gentleman, with regard to the insertion of iron hoops in constructions of brick-, work in cement. The principle, which was originally adopted, and its efficiency ascer tained, in the formation of the shaft of the Thames Tunnel, is founded upon the cohesive power of Roman cement, coupled with a system of ties, the most eligible substance for which, from a series of

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experiments performed by M. Brunel, appeared to be hoop iron. The piers having been constructed in the usual manner, it is proposed to pin or secure to them a mould for the purpose of determining the contour of the arch. A narrow rib may now be carried over, and keyed, using cement (with the occasional insertion of ties), which, by its adhesion to the brick being greater than the cohesion, enables the arch to be carried to any extent within the limits of the strength of the material. The several arches being in succession, once keyed, they will be in a state to receive the whole of the materials necessary to the completion of the bridge.. The bridge of the Santissima Trinità at Florence was particularly adverted to, affording a magnificent example of rubble construction, and the durability, of the material. The arches are composed of a mass of irregular stones embedded in mortar, having the consistence of a single stone, or of two stones abutting against each other at the crown.Ed. Arch. Mag.

The Mode of Heating the Elephant's House in the Zoological Gardens in the Regent's Park.-A mode of heating has been lately adopted with great success, in a new house prepared for the reception of the elephant in the Zoological Gardens, which appears well adapted for warming churches, chapels, and all other buildings having incombustible floors. It is thus described in the Times:- It consists in a common brick drain, which is conducted under the floor around the interior of the building. At the commencement of it there is a hole in the floor to the depth of about two feet, such as would be provided for the sink to any common drain; and the other end of the drain, instead of terminating in a sewer, or cesspool, finishes in an upright chimney shaft. A small quantity of fuel is then thrown in what may be called the cesspool at the opening, and lit: the effect is surprising. The downward pressure of the air to the vacuum caused by the fire produces a draught which is equal to' that of a furnace. All the smoke being driven. down through the tire, is there consumed, and, with the body of heat, rushing through the horizontal drain for the length of 110 feet before it reaches the upright or chimney shaft, all, or nearly all, the heat transudes through the floor, from which it ascends with as pure a warmth as that from the sun. We understand there is a floor of concrete nearly a foot in thickness over this drain, which, with the large quantity of humidity contained in it, must materially lessen the transmission of the heat: still the warmth is considerable."-Arch. Mag. for April.

Sir, I shall be greatly obliged to any of your correspondents who will, through the medium of your pages, inform me how the blowing-fan is applied for the ventilation of buildings, and if one is sufficient for two or three floors, what would be considered the most efficient situation, and the method of communication. Your early insertion will confer a favour on, Sir, yours respectfully, T. V.

Patents taken out with economy and despatch; Specifications, Disclaimers, and Amendments, prepared or revised; Caveats entered; and generally every Branch of Patent Business promptly transacted. Drawings of Machinery also executed by skilful assistants, on the shortest notice.

LONDON: Published by J. CUNNINGHAM, at the Mechanics' Magazine Office, No. 6, Peterborough-court, between 135 and 136, Fleet-street. Agent for the American Edition, Mr. O. RICH, 12, Red Lion-square. Sold by G. W. M. REYNOLDS, Proprie or of the French, English, and American Library, 55, Rue Neave, Saint Augustin, Paris.

CUNNINGHAM and SALMON, Printers,
Fleet-street.

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DESCRIPTION OF AN IRON SUSPENSIONBRIDGE CONSTRUCTED OVER THE BEOSE RIVER, NEAR SAGAR, CENTRAL INDIA, BY MAJOR PRESGRAVE.

(From the Journal of the Asiatic Society.)

We take particular pleasure in bringing to the notice of our readers the completion of this work of art, because it has been constructed entirely out of the resources of the country, being the first attempt at such an adaptation of native material and native workmanship. More than ordinary credit is due to the skilful engineer who planned and executed it, and who, moreover, from his long residence in India, could have acquired only a theoretical acquaintance with the system of suspension-bridges introduced within these few years, and now so rapidly spreading, in Europe.

The bridge was erected at the suggestion of T. H. Maddock, Esq., Agent to the Governor General in the Sagar and Nerbada territories, upon the plans, and under the sole superintendence, of Major Duncan Presgrave, Mint and Assay Master at Sagar.

Engineers in Europe, accustomed to find every thing provided for their wants, can have little idea of the personal labour which devolves upon their brethren of the craft in this country, where to the duties of architect and draftsman are not only added those of builder and overseer, but the whole of the subordinate trades of the brick-maker, carpenter, mason, and iron-manufacturer; in a climate, too, where little exertion produces exhaustion, and incautious exposure fever or death, and where the tools must be made, and the hands that employ them instructed ab initio. We will not say that the native mistrees and labourers are not capable of learning or of working well, especially in Upper Hindustan; the bridge before us is a sufficient refutation of that common and indolent remark: but all will agree that a peculiar talent is necessary to manage, instruct, and drill them; and this faculty is possessed by Major Presgrave in an extraordinary degree. The secret of his influence may be easily traced-he is a workman himself; he wields the hammer; makes and works the lathe; surveys the ground; searches the mines; smelts the ore; and has all the skill of contriving with the simplest means, for which the people of

this country are themselves so conspicuous.

The Sagar Bridge may indeed be called an experiment to try the resources of the country; to see whether the iron could be manufactured into bars of a quality fit for bridges; and whether these bridges could be made by native workmen who had never wrought or even seen iron of the dimensions required. The question has been satisfactorily answered; and even in point of economy, notwithstanding the numberless extra expenses incident to a first undertaking, and the distance, eleven miles, of the work from the yard at Sagar; the bridge has been pronounced cheaper than those on Calcutta, made with English materials: while of its design and execution no higher encomium can be given than the assurance of the visiting engineer, Major Irving, that he had seen nothing superior to it in Europe. The Governor-General is stated to have expressed equal satisfaction after inspection, and only to have regretted that so noble a bridge should be wasted upon so remote a locality! We have with permission taken a reduced copy of the elevation and plan, lithographed by M. Tassin, to accompany a private memoir of the Beose Bridge, the latter authentic source supplies us with the following particulars of the work.

The foundation was laid in April, 1828, and the roadway opened to the public in June, 1830. The iron of which it is composed is entirely the produce of the Sagar district. When the bridge was projected, it was still in the state of ore in the mines, whence it was extracted, smelted, and made into irregular small lumps, in the common native fashion. The working of the crude impure masses into good bars of the requisite dimensions, was a matter of very great labour and difficulty. The bridge is 200 feet in span between the points of suspension.

The piers, resting on the solid rock, 6 feet under the land level of the river, are 42 feet high to the roadway; being elevated 2 feet above the ordinary surface of the country. They have a base of 32 feet by 221, decreasing upwards in front 1 in 5, for the sides one in 8 feet; which gives on the road a superficies of 21 by 14 feet for each pier. On the sides are wing walls or abutments running back into the bank 26 feet.

The pillars, or rather arches, of suspen

sion, have a base of 21 by 12 feet, admitting a roadway of 9 feet broad. The arches are 15 feet high, and are faced with accurately wrought stone. The points of suspension are elevated 22 feet 4 inches from the road. The pillars have a total height of 33 feet, and the whole masonry from the rock 68 feet. The piers and abutments contain 82,488 cubic feet of masonry; the arched standards and bridge parapets 8,900; in all 91,388.

The platform measures 200 feet in length by 12 feet broad, and is calculated to weigh, with the chains, 52 tons. Supposing the bridge crowded with men, at 69lbs. per superficial foot all over the platform, the whole weight would be 120 tons: whence it is calculated that the tension to be sustained at each point of suspension would be 85,632 tons.

The suspending chains are twelve in number, arranged in pairs, three pair on either side, two feet above one another. They pass over rollers one foot in diameter, and are securely moored in masonry 16 feet below the surface of the road. The back chains are 101 fee long, rising at an angle of 27 degrees. The angle of the catenarian is 16 degrees with the horizon; the versed sine at the centre of the curve is 14 feet 3 inches.

The twelve main chains are of round bar-iron, one and a half inch diameter, bolted together in pairs; they are from

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15 to 15.5 feet long, and so arranged, that the vertical rods may fall from the joints of each chain alternately in parallel lines 5 feet apart. The descending chains are square, measuring 1 inch on the side; their lower ends pass through 24 conically-wrought stones, below which they are capped and keyed (figs. 1 and 2).

The connecting links of the chains, and indeed all the bolt-holes in the bars and the drops, are bored out of the solid iron, and broached to fit the bolts accurately (figs. 5 and 6). None were punched at the forge. The bolts are 1 inch in diameter, and are secured by rings, or washers and keys. Two adjusting links, with iron wedges, are fitted to each chain, close to the masonry, to regulate its curve and dip (figs. 7 and 9).

The method of constructing the rollers is thus described in the memoir :

"The iron rollers, twelve in number, weigh about I cwt. each. They are not solid, but are composed each of about 28 separate pieces of wrought-iron, viz. a centre tube or box for the axle, over which thick rings are driven; and an exterior drum, between which and the inner-ringed tube, flattened bars as spokes are driven. The centres are broached out clean and true; and cylindrical axles, 3.1 inch in diameter, were turned to fit: the ends of these axles rest on broad, thick iron bearings, mounted in very strong, solid frames of timber, well bolted, clamped, and blocked together; covered with pitch cement, and

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