Although it is not essential to adopt, exclusively, one system of apparatus, as the operation is more chemical than mechanical; yet an apparatus, for carrying the invention into effect, is shewn, in order that the modus operandi may be better understood.

In Plate IV., fig. 1, A, B, C, D, is a horizontal section of a furnace, constructed to receive four elliptical pipes. The furnace is arched, in the part A, C, B, in order to reverberate the heat, and drive it back on the pipes w, w1. wll, will. These pipes are placed on the focal plane E, F, of the elipsoid. a, a, represents the grating or bars of the furnace, to be heated with coal or coke; 1, 1, is the pot or retort, shewn in figs. 2, 3, and 4. This pot or retort is placed in a separate compartment, as seen in fig. 2, which is a vertical section, taken through fig. 4, at the line G, H.— K, is a connecting tube, from the retort and the elliptical pipes w.

In the section, fig. 2, the shape of the tube K, will be better seen; also its cocks u, and likewise its connection with the pipes w. l, is a safety valve; s, the cover of the pot or retort; L, is the ash-pit; and b, the door of the furnace; x, is an open space, roofed over, or a kind of shed, close to the furnace, and under it the pipes are emptied.

The arrows indicate the direction of the current of heat. This current traverses the intervals left between the pipes, and ascends behind them, passing through the aperture j, in the brick-work, which is provided with a valve or damper for closing it, as required. The heat passes through this aperture, and strikes against the sides of the pot when the valve is open. Another valve f, g, must also be open to expose the pot or retort to the direct action of the fire. The smoke escapes by a lateral passage into a chimney N.

It must be remarked, that there is a direct communication between the chimney and that compartment of the furnace which contains the pipes, so that the heat, reflected from the part v, strikes on the pot or retort only when the pipes w, w1, w11, wlll, are sufficiently heated.

In fig. 3, is shewn an inclined plane м, (also represented in fig. 2,) and the junction-tubes which connect the four

pipes with their gas-burners z, z, and the cocks m, m1.r, r, are covers, closing the pipes, and having holes formed in them; these holes are shut by the stoppers e.

Whether the pipes are placed in the vertical or horizontal position, it is always proper to be able to change the direction of the current of gas; this is easily done by closing, during one hour, (if the operation is to last two hours,) the cocks u, m1, and opening those u1, m; then the gas passes through u1, into the branch K, and entering w111, passes through q, into wl, through p, into w1, and through o, and w, and finally escapes by the burner z. During the following or other hour, the cocks u', m, must be closed; the cocks u, m1, being opened, the current then goes from u, into к, w, w1, wll, wlll, and escapes by the burner z', where it may be ignited.

The changing of the direction of the current dispenses, to a certain degree, with the labour required for stirring, with a spatula, the matters contained in the pipes; nevertheless, it is necessary, from time to time, to pass an iron rod or poker amongst the substances contained in the pipes. It is for this purpose that apertures are formed, so as to be easily opened and closed.

The patentee remarks, that although this operation is only described with reference to potash, for obtaining prussiate of potash, it is evident, that the same process is applicable to soda; and when the above-mentioned ingredients are employed, soda being substituted for potash, the result will be prussiate of soda.-[Inrolled in the Rolls Chapel Office, July, 1840.]

Specification drawn by Messrs. Newton and Son.

TO FREDERICK HARLOW, of Rotherhithe, in the county of Surrey, carpenter, for improvements in paving or covering roads and other surfaces, and in machinery for cutting the materials to be used for those purposes.— [Sealed 9th February, 1842.]

THIS invention consists, firstly, in a mode of combining and sustaining the blocks of wood, used for paving roads and

ways, in order to prevent any individual block from sinking below the others; and secondly, in a machine for forming grooves in those blocks.

In Plate V., fig. 1, is a transverse section, and fig. 2, a longitudinal section of a pavement, having the first improvement applied thereto. In the sides of the blocks a, q," composing the pavement, grooves b, b, are made, to receive the tongues or rods c, c, which extend from one side of the road to the other, their ends entering grooves in the sides of the gutter-blocks. The two rows of gutter-blocks d, d, are combined, and caused to support each other, by a tongue e, proceeding in a longitudinal direction, or parallel to the line of road. The blocks f,f, that compose the foot-way, are combined, in like manner, by tongues or

rods g.

If, at any time, a block is required to be removed, in consequence of a water-pipe bursting, or any similar occurrence, the block, represented in fig. 3, is substituted for it. This block is secured, in its place, by means of the tongues h, h, which are caused to enter the grooves b, b, in the sides of the two adjacent blocks, to the extent shewn by the dotted lines in fig. 3, by driving down the wedge i, until its upper end is level with the top of the block.

The machine, for forming the grooves b, b, in the sides of the blocks, and those that are required on the upper surface, to ensure a firm foot-hold for horses and other animals, is shewn, partly in section, in fig. 4,-figs. 5 and 6, being separate views of the rotary cutters, by which the grooves are made.

The grooving is effected by two circular metal plates or discs j, k, provided with suitable cutters, and mounted on the shaft, to which motion is communicated by a band, from a steam-engine, or other prime mover, passing round the drum m. The disc j, by which the grooves b, b, are made, has two kinds of cutters; those marked n, n, forming the sides, and those marked o, completing the groove. The disc k, has only one kind of cutter p, which produces the angular grooves q, q, fig. 2.

The blocks are grooved, by placing them on the tables

or platforms r, s, in contact with the gauge surfaces t, u, and then moving them forward to meet the rotary cutters. The positions of the grooves are regulated by the gauge surfaces t, u, which are retained in any required situation by the screws and nuts v, v.

The patentee claims, Firstly.-The mode of applying tongues and grooves to combine and sustain the blocks of wood, used in paving roads and such like ways.

Secondly. The mode of combining rotatory cutters j, k, with surfaces r, s, and gauge surfaces t, u, suitably for forming grooves, to receive tongues, in blocks used for wood pavements, and for forming grooves on the upper surfaces of the wood blocks, used for paving roads, as described.[Inrolled in the Inrolment Office, August, 1842.]

To EDWARD FRANÇOIS JOSEPH DUCLOS, of Clyne Wood Works, Swansea, Gent., for improvements in the manufacture of sulphur, sulphuric acid, and sulphate of soda.-[Sealed 11th July, 1839.]

THE first part of this invention relates to the manufacture of sulphur, and consists, firstly, in producing it by mixing two parts of sulphuretted hydrogen gas, with one part of sulphurous acid gas, in a receiver, and then, by the injection of steam, condensing those gases, and causing them to combine and form sulphur; secondly, in making sulphur from pyrites, by roasting it in a retort, and conducting the vapour, arising from such roasting, into a reservoir of water, where it is condensed, and forms sulphur.

The second improvement consists in manufacturing sulphuric acid, by subjecting the pyrites, (after being operated on in the manner above mentioned,) in the retort, to calcination, until it is converted into persulphate of iron, completely deprived of its water of crystallization; then by a further process of distillation, highly concentrated sulphuric acid is obtained.

The third improvement consists in making sulphate of

soda, by mixing common salt and copperas together, in a pulverized state, and subjecting them, for three or four days, to a temperature of about from 80° to 100° Fahr.At the end of this time, they are exposed to a red heat; by which means, hydrochloric acid is evolved, and peroxide of iron, and sulphate of soda, are obtained by solution.

The patentee claims, Firstly.-The mode of manufacturing sulphur from pyrites, as described.

Secondly. The mode of manufacturing sulphur, by bringing sulphurous acid gas and sulphuretted hydrogen gas together, and, by their mutual decomposition, producing sulphur.

Thirdly. The mode of manufacturing sulphuric acid, as herein described.

Fourthly. The mode of manufacturing sulphate of soda, as herein described.—[Inrolled in the Inrolment Office, January, 1840.]

TO CHARLES PAYNE, of South Lambeth, in the county of Surrey, Gent., for improvements in salting animal matters.[Sealed 13th October, 1840.]

THIS improved mode of salting animal matters, consists in exhausting the air contained in meat, and then, by pressure, causing the brine to fill the cavities, previously occupied by the air.

The apparatus employed, for this purpose, consists of a strong air-tight vessel or receiver for containing the animal matters, connected with an air-pump, for exhausting the air, and a force-pump, for supplying brine. The receiver has a perforated false bottom, upon which the animal matters are laid, and above them a perforated false cover is placed, to prevent them from floating, when the vessel is filled with brine.

The mode of operation is as follows:-The receiver, by means of the air-pump, is first exhausted, and half filled with brine; the air-pump is then worked for a short period, and the brine admitted, until the animal matters are covered;