after which, the pump is set in motion to exhaust the remainder of the air, and the brine is forced into the receiver, by the force-pump, until it raises a safety-valve, loaded to form one hundred to one hundred and fifty pounds per inch. After the meat has remained under this pressure for a period, varying from fifteen minutes to an hour, the lid of the receiver is removed, and it is taken out. If preferred, the process may be carried on without creating a vacuum in the receiver.

The patentee claims the mode of salting animal matters, (which are preserved or cured by salt,) by causing the brine to penetrate into such animal matters, by means of pressure, or pressure and a vacuum, when such matters are contained in a suitably-closed vessel.-[Inrolled in the Inrolment Office, April, 1841.]

TO EDWARD BROWN, of Whiterock, near Swansea, in the county of Glamorgan, copper smelter, for a new principle, applied to the roasting and refining of copper.— [Sealed 22nd June, 1839.]

THE patentee commences his specification by observing, that the usual process which the ore is required to undergo, in order that the copper may be separated from the impurities with which it is combined in the mineral state, are six in number, viz.,-first, calcining the ore; secondly, smelting the calcined ore; thirdly, calcining the coarse metal; fourthly, smelting the calcined metal; fifthly, roasting the metal; and sixthly, refining and toughening it.

The invention relates to the last two processes, and comes into operation when the coarse or blistered copper is in a state of fusion in the reverberatory furnace, covered by the slag or scoria, made in the process of roasting the metal.

Upon the fused metal, a flux is thrown, composed of equal parts of quick-lime and anthracite or other coal; or of equal parts of lime and wood charcoal, finely powdered. This is stirred in, by means of an iron rable, until the

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scoria, which was previously of a red color, is changed into a black frothy mass; it is then skimmed off the surface of the metal, which is afterwards tapped into the sand-bed. The quantity of flux required, is from half a bushel to a bushel for each charge of metal.

The blistered copper is now put into the refining furnace, and further roasted and melted, until it becomes pure, and ready to undergo the improved toughening process, which consists in covering the surface of the metal with a mixture of equal parts of finely-sifted lime and pulverized wood charcoal, or of lime and saw-dust, or lime and anthracite coal, coarsely powdered, (polling the metal as usual,) the quantity required, at the commencement of the polling, being about three Winchester bushels; an addition is afterwards made, if necessary, in order to preserve the surface of the metal from exposure to the air that passes through the furnace. By this process, the remaining portion of sulphur and other impurities, which are inseparable from the copper by the ordinary method, are effectually removed, and the metal becomes highly ductile and malleable.

The patentee claims the application or use of any portion of lime, in combination with any other matters or substances whatsoever, in roasting or in refining copper ores. -[Inrolled in the Inrolment Office, December, 1839.]

TO THOMAS CLARK, Professor of Chemistry in Mareschal College, University of Aberdeen, for a new mode of rendering certain waters (the water of the Thames being amongst the number) less impure and less hard, for the supply and use of manufactories, villages, towns, and cities.-[Sealed 8th March, 1841.]

THIS invention consists in purifying and softening water, by mixing lime-water therewith, in suitable proportions, and then, by subsidence alone, or by subsidence and filtration, separating the precipitate consequent on the mixture. The waters which this invention can be used for purify

ing and softening, are those that, in the first place, will indicate an alkaline action, on being tested by reddened litmus paper; secondly, being boiled, for two hours, in a glass vessel, and the greater part of the steam allowed to condense, will deposit a powder, soluble with effervescence in muriatic acid; and thirdly, will be softened, by such boiling, to an extent that is material for practical purposes.

The degree of softening may be ascertained by weighing the water, and the vessel containing it, previous to boiling, and weighing them again after the boiling and subsequent cooling, replacing, with distilled water, any loss that may have occurred in the form of steam; then, if the hardness of the water that has been boiled, and of the water in its original state, is measured, the difference between them will shew the amount of softening the water has undergone.

The patentee measures the hardness and alkaline property of the water, and ascertains if any caustic alkaline or earthy matter is dissolved in it, by means of a number of chemical agents, tests, and standard solutions, which do not, of themselves, constitute a part of this invention.

The general rule of ascertaining the proportion of limewater requisite to be used with the water to be purified, is to measure the alkalinity of both waters, and use them in the inverse proportion of their respective degrees of alkalinity; thus, if the alkalinity of the lime-water is sixteen times greater than that of the unpurified water, one measure of the former is used to every sixteen measures of the latter. —[Inrolled in the Inrolment Office, September, 1841.]

TO THOMAS WILLIAM BOOKER, of Melin Griffith's Works, near Cardiff, iron-master, for improvements in the manufacture of iron.-[Sealed 22nd February, 1841.] THESE improvements consist in accelerating the operation of converting cast-iron into malleable iron. It consists in running off the metal, in a fluid state, after the refining process is complete, from the refinery into the puddling furnace, through a passage that connects the two furnaces. The metal is then puddled, and divided into lumps or

balls, as usual, in readiness for passing between the rolling cylinders, or other apparatus used for compressing or forging the iron. [Inrolled in the Inrolment Office, August, 1841.]

1

TO WILLIAM HUTCHINSON, of Sutton-on-Trent, Nottinghamshire, seed-crusher and oil-cake manufacturer, for certain improvements in the manufacture of oil-cake or seed-cake. [Sealed 5th April, 1841.]

THESE improvements consist in making oil-cake of linseed, mixed with barley, wheat, peas, beans, or other grain or pulse.

The barley, &c. is first riddled, to free it from any rubbish that may be mixed with it, and is then ground into meal. Twelve quarters of this meal are mixed with nine quarters of crushed linseed, and ground under vertical stones into a fine flour, which is then put into a kettle, and heated by steam to 2120 Fahr. It is removed from the kettle, while in this hot state, into an ordinary stamper press, in which all the superfluous oil from the linseed, that is not taken up by the barley or other grain, is expressed, and the making of the oil-cake finished.

The patentee claims the manufacture of oil-cakes, by the admixture, with linseed, of barley, wheat, oats, peas, beans, tares, or other grain or pulse, in or about the proportions, and in the manner above described.―[Inrolled in the Inrolment Office, August, 1841.]

Original Paper.

ON DREDGE'S SUSPENSION BRIDGE.
BY MR. W. TURNBULL.

Amongst the numerous improvements that have been made in the different branches of mechanical science within the last few years, that which has reference to the construction of suspension bridges is one of the most important. It had long been observed,

that when a bridge is erected on the principles of the common Catenary, there is a much greater quantity of material employed than is absolutely required for strength, and that the surplus materials, instead of being advantageous to the stability of the structure, is conducive to a positive injury. In consequence of this, a great many attempts have been made by different skilful and experienced individuals, to introduce some variation, either in the form of the chains themselves, or in the mode of connecting them; but not one of the numerous schemes that had been suggested, was found of sufficient consequence to supersede the original plan, until Mr. Dredge of Bath was led to the discovery of the tapering chain and the obliquesu spending-rods,—a discovery which he first promulgated in the year 1836,* and shortly afterwards he had the opportunity of testing its utility, by the erection of the Victoria Bridge a oss the river Avon, in Somersetshire. Since that period, the subject has been discussed by almost every learned society in Europe and America, and is, even now engaging the attention of philosophers beyond the GANGES.

Mr. Dredge's invention, like every other bold and original scheme, has experienced much opposition; and what is not a little singular, those very individuals who ought to have rallied in support of it, have been its most inveterate and strenuous opponents; and they still continue to manifest their opposition to its adoption, by pertinaciously adhering to the absurd and selfdestroying form of the Catenarian curve.

This curve, as is well known, is formed by a perfectly flexible chain or rope, of uniform figure and density, which hangs freely suspended between two fixed points, in a vertical plane. It is therefore manifest, from the very nature of the description, that the material of which the curve is composed, is self-destructive in a state of suspension, although in a reverse position, the weight would be conducive to stability. It matters not of what material the chain is constituted, provided it be uniform and perfectly flexible; for a chain, of the same length, whether it be made of

* For Specification of this Patent, see Vol. XI. p. 1, of our present Series.