retain the pinion in its position. Fig. 19, is a plan or top view of the press shewn in fig. 17; and fig. 20, is another plan of the press exhibited in fig. 18.

In fig. 17, the top of the mould c, is closed by means of a metal plate dovetailed on its edges, and which slides in dovetailed grooves made in the sides b, b, of the mould to receive it. Fig. 19, shews the same in plan; in figs. 18, 20, 21, and 23, the top of the mould is shewn as closed, by means of a metal lid c, mounted either upon a rule joint hinge, or upon hinges on one side of it, and the other kept closed when in use, by means of a catch, either with or without a spring. Fig. 22, exhibits the top of the mould as opened.

For compressing curved tiles in the mould, the under side of the top of the mould must either be hollowed, or hollow blocks be introduced, as shewn in figs. 22, and 23; the top of the piston being also rounded to correspond therewith; or another rounded block be also introduced into the mould, as shewn in figs. 22 and 23.

Fig. 24, is a top view of a spring catch brick mould, intended to mould bricks by hand; and fig. 25, represents the same as opened; a, a, are the sides of the mould; a joint b, is made at one of its angles, extending the whole depth of the mould. Two angular ears, one of which is shewn at d, in both figures, are formed one upon the upper, and the other upon the lower edges of the end of the moveable part of the mould; and are passed through corresponding slits or holes, formed to receive them in the counter part of the mould, and thus to keep the sides steady. The end c, being also received into another gap made inside of the mould, a spring catch is affixed by screws upon the outside of the end of the mould (between the ears) which passes through a square hole made to receive it, in the corresponding side of the

VOL. VIII. SECOND SERIES.

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mould, and hooks itself fast. when the mould is shut, but can be readily released, by pulling the spring catch back.

Having thus shewn and described various modes of carrying these inventions into effect, the Patentee lastly declares that he does not mean or intend hereby to claim as his improvement, any of the various parts which may have been already known or in use, but only in combination; nor does he mean to claim the mode of grinding clay or other materials, or mixing, or tempering them in mills, by means of large stones employed as wheels, where they always run in the same circle or track; but he does hereby claim the power of causing them either to run in spiral paths, or in circular ones, continually varying in their diameter, until the materials spread over the whole bottom of the pit shall have been repeatedly operated upon. The Patentee says he has seen in Lancashire, in several of the potteries, stones of four or five feet in diameter, used in grinding or tempering clay, and and revolving spirally, by the action of screwed shafts; but one end of which shafts rested on a wheel, and the other end supported upon a post in the centre of the floor, so that the stones were suspended upon the shaft at the height of two or three inches from the floor; and which said floor was merely a flat surface, without borders or forming a pit; whereas his wheels came into contact with the floor of the pit, excepting when the clay or other substances intervene, and raise them therefrom. The borders of the pit also confine the clay or other materials, and prevent them from spreading sideways, as in the ordinary methods. To the clay mills, or stones revolving on a screwed shaft, as above described, he has therefore no claim whatever. It may be well to observe that the bricks or balls of clay, previously to being

placed in the press must be in a half dried state, or in the same state as common bricks are taken, to be "smoothed or polished," and their external surface, or sides, ends and faces be rubbed with fine sand or dust (the latter of which is generally found in abundance in or near brick kilns), in order to prevent them from adhering to the moulds. It is also observed that this Patent is not for pressing bricks, tiles, cornices, &c. generally, but only for the particular description of presses that have been herein shewn and described.[Inrolled in the Rolls, Chapel Office, February, 1831.] Specification drawn by Mr. Gill.

To SAMUEL HALL, of Basford, in the county of Nottingham, cotton manufacturer, for his having invented or found out a new method of, and apparatus for generating steam and various gasses to produce motive power.[Sealed 31st May, 1828.]

THE intention of the Patentee is, to combine highly elastic airs with steam, for the purpose of working the piston of an engine constructed upon the principle of the single stroke atmospheric steam engine.

The very great advantage expected to result from this union of elastic air with steam as a motive power, induced us to withhold our report of this invention, until sufficient time had been afforded to the Patentee to bring his plans into effective operation; it does not however appear, that the anticipated advantages have yet been realized, whether from defects in the construction of the apparatus, or in the principles upon which it is founded, we are not informed; but, that a something is still wanting, appears evident, and that something we understand, the inventor is about to supply, under the protection of a new patent.

The invention specified under the above title, is divided into four heads; first, the construction and adaptation of an air cylinder, which is to be employed as a pump, to inject and condense a quantity of atmospheric air intended to be heated by passing through the furnace; second, the peculiar construction of generator from which the steam is to be evolved; third, the receiver, into which the steam and heated air is passed, previous to its admission into the working cylinder; and fourthly, the working cylinder itself, furnished with peculiar entrance, and exit valves for the admission, and discharge of the heated air and steam.

One of the objects proposed, is the superior combustion of the fuel in the furnace, promoted by the artificial atmosphere of condensed air, which causes it to give out a much greater degree of heat, than the same quantity of fuel would do under any other circumstances, and consequently effects an economy in its consumption.

The furnace is made within a cylindrical iron vessel of very considerable substance, in the solid parts of which, various tubes or channels are formed for the reception of the water intended to be evaporated into steam. These tubes or channels are all connected together by contorted passages at the top and bottom of the generator; and an aperture at bottom allows part of the steam to discharge itself into the furnace.

The piston of the pump by which the atmospheric air is forced into the furnace, is intended to be of about ten times the area of the piston in the working cylinder, in order that as the two pistons work together simultaneously, the former may throw in very large volumes and condense the atmospheric furnace within the generator, to a pressure of about a hundred and fifty pounds upon the square inch.

The steam and the heated air both pass into a vessel called a receiver, which is furnished with an inlet and outlet valve, and from them they proceed through the induction aperture, to the under side of the piston in the working cylinder, in the usual way.

The elastic force of the steam and vapours raise the piston until it has nearly reached the top, and then an eduction valve opening, allows the steam and vapour to escape, when the piston descends again in its cylinder, by the superincumbent pressure of the atmosphere, and thus the mechanical or motive power is obtained, as in other single stroke engines.

The upward stroke of the piston in the working steam cylinder, produces a downward stroke of the piston of the air cylinder, owing to their mutual connection to a vibrating beam, and the act of injecting a volume of air, into the furnace as above described, causes a similar volume to be forced therefrom into the receiver.

In the event of the air cylinder being no larger than the working steam cylinder, it is proposed to work the piston in the steam cylinder, by expansive steam and vapour, that is to shut the induction valve, and thereby cut off the supply of steam and vapour, when the piston has made about one tenth part of its upstroke, the remainder of the stroke being effected by the expansion.

These are the leading features proposed, in which it would appear that the effect of the increased elasticity of the condensed air, caused by heating it in the furnace, is the only additional power anticipated.

The Patentee has descanted upon the minor parts of the machinery at great length, in a most elaborate specification, and with numerous figures of the detached parts, and their susceptible variations in detail, but for the reasons before given, we do not think it necessary at