placed upon the rotating mould, at which time it would (if the work could be perfected) produce a box of a larger or smaller size than is required. This recess d, need not, however, be of the precise form of the section of the article to be made; but it may, with advantage, be of larger proportions than the recess c, provided that some portion of its edge shall touch the periphery of the box or other article, and thereby ensure an unvarying diameter.

In using the gauge, the lower part of the edge b, at b*, is to be brought flush against a raised part of the rotating mould A; and, being steadily held there by the workman, the gauge will remove all the superfluous clay, and perfect the form of the box or other article, which must necessarily be of the exact form and proportions indicated by the recess c, of the gauge ;—the diameter being determined, as above stated, by the combined action of the two recesses c, and d. The gauge is now drawn off the clay, and the box or other article is removed from the throw-wheel or jigger to be dried. The above described operation is then repeated on another bat and ball of clay. When sufficiently hard to handle (which they will be in about two hours), the boxes or other articles are severally placed on a rotating-wheel, where their edges are trimmed, and their surfaces are also smoothed by suitable tools;-the bottom edge of the box, if required to have a rim, as shewn in the drawing, being trimmed with a tool shewn at fig. 4: they are then ready to undergo the firing operation.

From the foregoing it will be understood that the doublegauge is applicable to the formation of circular articles, the sectional figure of which is formed by vertical lines (the gauge being capable of removal therefrom, without disturbing the clay or other plastic material which it has brought into the required form); but it will be obvious that the gauge is also applicable to the formation of articles, the sides of which, in their sectional figure, incline upwards, to opposite sides of a common vertical line, as shewn in the diagram, fig. 5; and therefore such forms of articles may, in like manner to those with vertical sides, be completed (with the exception of the finishing) on the throw-wheel or jigger, and made ready for

the firing process; thus dispensing with the use of the lathe, and effecting a great economy in the manufacture as well as an improvement in the article produced.

When articles of a greater or less exterior or interior diameter are required to be made, it will, in most cases, be only necessary to change the size of the gauge; but when a considerable increase or diminution in size is wanted, the mould A, should also be changed.

The patentee, in conclusion, states that he does not mean or intend to claim the application generally of gauges, ribs, or profiles, for forming upon the throw-wheel or jigger the exterior and interior (either singly or simultaneously) of jars, boxes, pots, or other similar articles; but he claims the exclusive use of a double-gauge, whereby he is enabled expeditiously to determine and ensure the exact and uniform capacity and dimensions of any number of jars, or boxes, or pots, or other similar articles, manufactured upon the throwwheel or jigger; and at the same time can sufficiently perfect. such articles, while in a plastic state, as to render the operation of turning at the lathe unnecessary.—[Inrolled in the Petty Bag Office, June, 1848.]

TO WILLIAM LONGMAID, of London, Gent., for improvements in the manufacture of alkali and chlorine.—[Sealed 2nd November, 1847.]

THIS invention consists, firstly, in heating sulphate of iron or other metallic sulphate (deprived of moisture) with chloride of sodium in a close furnace, into which dry atmospheric air is admitted; whereby a product is obtained, containing sulphate of soda and oxide of iron, and chlorine is evolved. Dry sulphate of iron is obtained by evaporating the mother liquor of the copperas manufacture or the crystals of green copperas in a reverberatory furnace, at a low temperature (taking care not to expel the sulphuric acid); the resulting product is sulphate of iron, nearly free from moisture. 78 parts, by weight, of the dry sulphate of iron are mixed with about 60 parts of chloride of sodium, in a pulverized state; and then the patentec proceeds in the manner described for producing

chlorine in the specification of his patent of August 4, 1845* : by this means, sulphate ash, containing sulphate of soda and oxide of iron, is obtained, and chlorine is evolved, which may be used in the manufacture of chloride of lime and other compounds of chlorine. Or the patentee adds to a hot saturated solution of chloride of sodium, an equivalent of sulphate of iron or other metallic sulphate, and evaporates the mixture to dryness in a reverberatory furnace; then he removes the partially calcined mass to a close furnace, and proceeds as before.

The second part of the invention consists in treating sulphate of iron or other metallic sulphates, or iron pyrites or other sulphurous ores, with chloride of potassium, in a reverberatory furnace, in the manner described in the specification of a patent obtained by the present patentee, Oct. 20, 1842,† when treating iron pyrites or other sulphurous ores with chloride of sodium. The product, which contains sulphate of potash and oxide of iron, or other metallic oxide, is lixiviated, and the liquor so obtained is evaporated to dryness, or otherwise used.

The third part of the invention consists in treating sulphate ash (being the product of the first process, above described, or being the product of the decomposition of iron. pyrites or other sulphurous ores and chloride of sodium, as described in the specifications of the two patents before mentioned), by mixing it with small coal or other carbonaceous matter, and heating the mixture in a suitable furnace. 200 parts, by weight, of the sulphate ash, containing about 130 parts of sulphate of soda, are mixed with about 70 parts of small coal, and the mass is placed on the back bed of an ordinary black ash furnace; when sufficiently heated, it is moved on to the bed nearest the fire; and then another charge is placed on the back bed. After the charge is well fluxed, which usually happens in from fifty to sixty minutes, it is drawn; and when the ball or ash, so produced, has become cool, it is removed to the vats, and the alkaline matter dissolved out. The liquor, thus obtained, is brought into

* Sec Vol. XXVIII. of our present Series, p. 172. † See Vol. XXIV. of our present Series, p. 274.

contact with carbonic acid by any of the ordinary means in use for carbonating alkaline liquors; it is then evaporated to dryness, and crude carbonate of soda is produced.

The patentee remarks that, in preparing the sulphate ash for the manufacture of alkali without the use of lime and with one lixiviation, he selects pyrites as free from silica as possible, or he employs the sulphate ash produced in the first process.

The patentee claims, Firstly,—decomposing common salt with sulphate of iron, to obtain sulphate of soda, oxide of iron, and chlorine. Secondly,-decomposing chloride of potassium with metallic sulphates, or iron pyrites, or other sulphurous ores. Thirdly,-working the sulphate ash into alkali at one operation, without first lixiviating it to separate the sulphate of soda from oxide of iron and other matters.[Inrolled in the Inrolment Office, May, 1848.]

TO CHARLES MURLAND, of Castlewellan, Ireland, flax-spinner, and EDWARD LAWSON, of Leeds, in the county of York, machine-maker, for certain improvements in machinery for preparing and spinning flax and other fibrous substances.[Sealed 18th September, 1845.]

THESE improvements in machinery for preparing and spinning flax and other fibrous substances apply, in the first place, particularly to machines employed in the preparation and spinning of flax, and consist in a novel and peculiar combination and arrangement of two ordinary and well known machines, by which they are so worked, in immediate connection with each other, as to perform the operations of drawing" or "slivering" and spinning in one machine. The machinery thus employed is the well known "screwgill," as worked in connection with the preparation machinery and the common spinning-frame. The "gill" is of that class of preparing machines employed for opening, straightening, and separating the fibres of flax, hemp, long wool, and other materials of a similar description, in the operation called slivering. The several parts and operations of this

machine, and also of the common spinning-frame, are so well known, both to the practical operative and the mechanic connected with the business of preparing and dressing flax, &c., as to require no detailed explanation thereof: in the following description they will, therefore, be merely generally alluded to.

In Plate II., fig. 1, is a front elevation of the mechanism; and fig. 2, is a vertical section, taken at the dotted line a, b, in fig. 1. This improved combination of machinery is designed to dispense with the operation of roving and twisting, in the preparation process, and thus to improve the uniformity and strength of the yarn; and also to supersede the use of bobbins, and their transmission from one frame to another in such operations; and, consequently, to prevent any injury to the slivers, between the preparation and spinning processes. A, A, A, represents the carriage or stand of the screwgill, and B, B, B, the framework of the spinning-machine. The mode of operation of this combined machinery is as follows:-The slivers of flax are brought from the drawing-frame in the cans a, a, and placed one above the other upon the creel or stand b, (which will economize space, instead of all being placed upon the floor as usual,) they are then passed over the conductor rod c, c, onwards to the back rollers d, d, and from thence through the gills e, é, over the front drawing-roller f, f, through the water-trough g, g. The sliver then enters the ordinary spinning-frame, through the front and back rollers h, h, (which are mounted, as usual, in their stands or carriage i, i,) and proceeds through the thread-plate j, to the spindle k, k, k,-the whole being driven from the cylinder shaft 7, 1, and the train of gearing m, m, m.

The second part of the invention applies to the operation of spinning only,-the improvements being, in this instance (and by way of illustration), shewn as applied to spinning, twisting, or doubling flax; but it is equally applicable, in principle, to spinning cotton and other fibrous substances, the only difference being in the size and weight of the flyer. It is an improvement in the flyer of the spindle, or that part which conducts and winds on the thread to the bobbin, and is shewn, in three different (front, side, and top)