(Eve's Rotary Engines. 1825.)

passing, thus allowing no steam to escape between. The said wing c then passes again by the steam pipe f, and is acted upon as before described, and so on in rotation. The cylinder a, which is firmly fixed to its axis b, rests on one side on the outer case e, through which the axis projects; but as there is some friction produced by the revolution of the said cylinder at its two ends touching the outer case, I have placed a false end h h, under the opposite end of the cylinder, which false end slides on the axis b freely, and has a thread cut at the end, by means of which, and the adjusting nut i, the cylinder, if worn at the two

ends, can be easily tightened and adjusted. The adjusting nut is confined by the collar k, which collar is screwed to the outer case. The conical shape of the small runner, which can likewise be moved upwards or downwards in the outer case, serves to keep the two convex surfaces of the cylinder and cone in contact.

"The groove d, in the conical runner, is cut into a separate piece of metal, which slides by an adjusting screw • up and down; so that when the engine is adjusted, the groove d, on the piece of metal, into which the said groove is cut, can be moved up and down, so as to fit the wings of the cylinder.

"Letters n n, in fig. 2, represent two cog-wheels running into each other, attached on the outside of the engine to the axis of the cylinder and cone, placed there for the purpose of producing a corresponding revolution of the said cylinder and cone, thus causing the groove of the cone to present itself regularly to the wings of the cylinder; o is a pinion fixed to the other end of the axis, by means of which any machinery can be put into motion.

"Another variety of constituting a steam engine on this principle is shown by an end section view in fig. 5, and an external view in fig. 6. This engine has a cylinder with two small conical runners on each side, the said conical runners being of the same construction as before described, with one groove cut into each, and being one third of the diameter of the cylinder. There are two induction and two eduction steam pipes, and, although the engine may be, with the exception of the addition of one of the conical runners, exactly of the same size as the one first described, a double quantity of steam is requisite, and twice the power of the former engine is gained: the steam enters through the pipe ƒ a, and acts on the wing c, which after having passed pipe g o, where the steam escapes, falls into the groove d of the lower cone, and appearing at the induction steam pipe fb, is loaded again with steam pressure, which it discharges at the second eduction pipe go, and then enters the groove of the upper cone, which having passed, it is loaded again at the first-mentioned induction pipe.

"Letters m m are bridges, by which the spindles on axis bbb are supported. This engine has three cog-wheels nnn attached to the three spindles, so as to cause the cylinder and cones to revolve in unison, and, like the first described engine, a pinion o on the opposite end of the axis of the cylinder. Fig. 7, shows an end section; fig. 8, a longitudinal section; and fig. 9, the exterior.

"The two conical runners in this engine are of an equal length and diameter, each has two wings or pistons attached, and two grooves cut into it, and in revolving in opposite directions, the wing of one runner falls alternately into the groove of the other. The steam enters by pipe ƒ, and as the cylinders are running in contact, it cannot escape between them, but acts upon the two wings in opposite directions, and escapes at the eduction pipe g, after the said wings have passed the same. By reference to fig. 8, which represents a longitudinal section, it will be seen that the two cones have each two false ends pp, sliding freely on their spindles; the two outer cases e e fit over the runners and their wings exactly, each of the four false ends has an adjusting nut, by which the engine is tightened, if steam should escape, or slackened, if it should run too tight. Each pair of the false ends, where they join, have a plate that connects them and breaks their joints, so as to prevent an escape of steam; this plate p slides into the groove r, cut out of the false ends, as exhibited by fig. 3, and fig. 4, the former shewing an end view of the false ends with the connecting plate in the middle. On these false ends packing rings, g 9 g, which are confined to the sliding plate as exhibited in the latter figure, are placed. These rings press against the hollow outer cases, and prevent any steam escaping by them. These packing rings are shown in section, in fig 8. It will be evident that the false ends need not be made true, if the connecting plates and packing rings, as above described, be adopted, and that the engine, if provided with moveable false ends, conical runners, and the afore-described connecting plates, and packing rings attached, as shown in fig 8, can always be kept steamtight, and by use the various parts, on which there is any friction, will fit better.

'This engine approaches nearest to Mr. Flint's, described at page 183, and is of course liable to the same objections. A patent was obtained in 1826, by Louis Joseph Marie, Marquis de Combis, for an improved Rotary Engine, the principle of which is as follows:

"A piston is made to circulate within a vertical hollow ring, by steam admitted alternately at two opposite points of the diameter of the latter, and discharged through perforations in the central boss of the piston, and in its tubular axis; which hollow ring is separated into two equal portions, by sliding valves, that pass across its cavity on to the axle, at its different sides, and which are withdrawn successively as the piston approaches to them, and are instantly replaced as soon as it has passed.

"The form of the case that contains the hollow ring may be conceived by supposing a flat cylinder with its angles rounded off, from which, rectangular pieces project at opposite sides of its diameter, to contain the sliding valves. This case is divided into two equal portions, by a section through the middle of the axis of its cylinder, and at right angles to it, each of which portions is again divided into two equal parts by another section, that passes in the plane of the axis, and through the midst of the valve receptacles; the four pieces, thus formed by the two sections, are united by screw bolts and nuts, passed through flanches cast on them for their reception. A perforation is made through the middle of the cylinder, in the line of its axis, whose diameter is between three and four times greater than that of the revolving axle of the engine that passes through its centre; and at equal distances from it, all round close to the sides of the cylinder, is formed the annular cavity, or hollow ring, in which the piston moves.

"The axle of the engine projects a considerable distance beyond the cylinder at each side, to allow space on it sufficient for the reception of the main wheel (by which it gives motion to the machines with which it is connected,) for the fly-wheel, and for the parts that impel the apparatus, which works the sliding valves of the hollow ring, and