generated and produced by the fluction* of its point, as in the instance of the convex sphere. Tenthly, I convert solid wood, or other materials, into a thin concave shell, similar to a dish. I cut them alternately out of each other, beginning at the smallest, by means of another tool or cutter, likewise moving on a stationed centre, as before, exactly on a level with, and perpendicularly true with the centre of the mandrel or shaft of the machine on which the work is fixed. This tool, or cutter, is made at its exterior point, or cutting end, of such a shape as best suits the nature of the work; and its shank, or stem is bent to the exact circle the concave is meant to be: it is then fixed on an arm or frame calculated to receive others of different circles, according to the work; in fact the same frame may be used which is above described to hold the tool for cutting spheres, either of the concave or convex kind. The tool must be fixed on this frame or arm, as above mentioned, at such a radial distance from the centre on which the frame or arm turns, so as to form a quadrant with one leg, turning on its centre, and the tool forming the periphery with its cutting point projecting to the line of the deficient leg. Before this tool begins its action, a common rest must be applied close to the face of the work, in order to support the tool when it begins its cut; and on which rest the tool will slide till its point proceeds under the controul of the centre on which its frame is fixed until it reaches the horizontal line of the lathe's centre, when the part cut off, or the inner dish, will fall from the stock, and leave the rest for the operation of another tool, of a larger circle. Thus the operation may be repeated till the whole lump is converted according to the intentions of the owner. Thus have I given the clearest description of my invention I am able. In witness whereof, &c. * Compared with the record. Specification Specification of the Patent granted to MATTHEW MURRAY, of Leeds, in the County of York, Engineer; for new combined Steam-Engines for producing a circular Power, and for certain Machinery thereunto belonging, applicable to the drawing of Coals, Ores, and all other Minerals, from Mines; and for spinning Cotton, Flax, Tow, and Wool, or for any Purpose requiring circular Power. my Dated June 28, 1802. With a Plate. To all to whom these presents shall come, &c. Now KNOW YE, that in compliance with the said proviso, I the said Matthew Murray' do hereby declare that said invention is described in manner following; that is to say: My new combined steam-engines, and parts thereunto belonging of my invention, are described in the figures and drawings hereunto annexed and explained. The letters refer to the same figures in all the drawings hereunto annexed and explained. Figs. 1, 2, 3, and 4 (Plate VIII.) represent front and side views, or sections, of the combination of parts constituting my new engine. A, the steam-cylinder. B, the piston - rod. C, C, connecting-rods, for connecting the piston-rod to pin in the wheel D. E, a wheel, fixed to the side of the cistern IIII, with the teeth inwards, to admit the teeth. of the wheel D, for the purpose of giving a parallel, direction to the rods C, C. F, a plain wheel upon the fly-wheel-shaft G: the wheel F is furnished with a double conical centre for the wheel D to run upon, the principle and form of which is fully described in Fig. 10. H, is a fly-wheel, with a circular section of the rim, which I consider as a part of the invention. IIII, is a cistern, cistern, or frame of plates, on and in which the whole combination of materials constituting my engine is fixed, and part thereof inclosed by a door aa. K, K, two wheels, one upon the fly-wheel-shaft G, the other upon the crank-shaft L: these wheels and crank are for the purpose of working the lever R in Fig. 4, which lever gives immediate motion to the air-pump P, the cold water pump Q, and the hot water pump S. T, is an iron bar for supporting the crank-shaft L. M, is a slide-valve for opening and shutting the communication of the steam - pipes marked N, N, N, and is described in Figs. 5, 6, 7, 8, and 9: a motion for the slide-valve is taken from the crank-shaft L by levers, or otherwise, as the nature of the valve may require. O, O, in Fig. 4, are pump-pipes to the well, for drawing the water into cistern IIII, in which the cold water pump is immersed. V, a pipe, for running off the spare water; the parts so combined form a perfect engine, without requiring any fixture of wood, or any other kind of framing than the ground it stands upon, and is transferable without being taken in pieces, (the motion of the fly-wheel shaft giving circular power to any process or manufactory requiring circular motion,) or for irrigating land, or for the various purposes of agriculture. Figs. 5, 6, 7, 8, and 9, represent various forms of my new slide-valve in its application to the steam-engine; the principle of which consists in moving in a circle part of a circle or straight line, by means of flat surfaces or faces (or nearly so), sliding or moving upon each other, for the purpose of uniting the necessary apertures in the steam-pipes or cylinders. Fig. 5, is a view of a circular flat sliding-valve; the dotted lines shew the avenues to the steam-pipes. a 1, is a figure representing the upper or moveable part of the slide-valve, Fig. 5, where the conducting or uniting cells are |