its entire passage in the tube, and is thus fed into the engine or engines in the shape of steam.

Fig. 7, represents a longitudinal section of the coiled tube and its casing; and fig. 8, a front view of the same, with the casing removed to render the arrangement evident. a, is the casing; b, the tube; the lateral parts or members of the coil at the bottom form a number of fire-bars, which are kept apart; as also those at the top, by pins æ, bolted into the sides of the casing. c, is the ash-pit; d, represents the part of the coil for feeding the boiler with water, which is, in the first instance, supplied by a hand-pump; as soon, however, as the engine gets started, the feed-pump, attached to the engine, comes into action, and supplies water. There is a branch at e, fitted with a cock at f, for the purpose of regulating the supply of water to the engine.

In order to bring this part of the arrangement under the eye of the attendant, the branch (which is represented as supplying the excess water into a funnel g,) is fixed in any convenient way into the side of the boiler casing; and connected with it is a pipe, for returning the surplus water into the reservoir; or this regulation of the supply might be made self-acting.

m,

is the blowing apparatus, consisting of a set of fans, revolving upon a shaft, fixed in a case; n, is a throttlevalve, having a lever connected with it at the command of the attendant, to enable him to regulate the draft of the fire. The throttle-valve, and ash-pit doors, are so fitted, that the draft can be almost entirely shut off, when required, so as to damp the fire in a very short time; thus giving the attendant sufficient command over it.

Another part of this invention consists in using, in this and other boilers, water, rendered slightly alkaline, by the addition of lime; for this reason, that by precipitating the free carbonic acid, and the earthy salt (carbonate of lime)

contained in ordinary water, incrustation and "priming" are prevented in a great degree, which in locomotive engine boilers is a very serious detriment, as they are more than others exposed to priming; that is, having much of the water blown out of the boiler with the steam: in such cases, the earthy salts, which are deposited from the water, are of a gritty nature, some of which are blown through the interior of the engines.

When using a boiler made entirely of pipes, a dilute acid, as hydrochloric, or dectic, is occasionally passed through it, to dissolve any deposited lime.

The patentee claims, firstly, the general combination and arrangement of the several parts represented in the drawings, and described in the specification.

Secondly. The use of a bar, such as that shewn at fig. 3, besides which no framing is required, nor any other support but that derived from the shaft.

Thirdly. The application of the boiler, where great lightness and economy are desirable, such as in carriages, or for locomotion on common roads, and for which purpose the patentee only claims it.

Fourthly. The use of lime, as set forth in the specification.-[Inrolled in the Rolls Chapel Office, January, 1841.]

TO BENJAMIN BEALE, of East Greenwich, Kent, engineer, for his invention of certain improvements in engines to be worked by steam, water, gas, or vapours.-[Sealed 13th July 1841.]

THIS invention relates, firstly, to those peculiar constructions of steam-engines, commonly called or known by the name of rotary engines, in which the power, exerted by:

VOL. XX.

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the elastic force of steam or other fluid, is communicated from a central rotary axle; secondly, in an improved mode of applying the power produced by the improved engine or any other engines, to the paddle shaft of steam-boats; and thirdly, to the construction of the boilers by which such or other steam-engines or steam apparatus may be worked.

In Plate XVII., fig. 9, represents an end elevation of one of the improved engines; fig. 10, is a side view of the same; and fig. 11, a transverse section, taken through the middle of the engine. A, A, A, is a hollow cylinder, within which a drum wheel revolves excentrically, carrying several cylin drical pistons, which are to be actuated by the power of steam or any other fluid. The steam from the boiler, hereafter described, or from any other suitable boiler, is conducted by a pipe a, into the valve box b, and thence proceeds by the induction passage c, to the interior of the cylinder. The drum-wheel d, is fixed upon an axle e, e, which passes through two circular apertures in the ends of the cylinder A, and is properly supported on stationary bearings f, f, and packed in sockets g, g, contiguous to the ends of the cylinder, so as to render both ends of it steamtight. The apertures in the ends of the cylinder, through which the axle e, passes, are excentric to the interior of the cylinder, so much so, as to cause one part of the periphery of the drum-wheel d, to work against a curved part prepared for it in the interior of the cylinder, and thereby to produce a steam stop; consequently, the steam way within the cylinder is of a crescent form. Longitudinal recesses i, i, i, are made in the drum-wheel d, for the reception of the loose rollers or cylindrical pistons h, h, h. These cylindrical pistons have no axles, but are made perfectly flat at their ends, and of such lengths as will enable them to fit accurately against the internal ends of the cylinder, steamtight, but yet capable of revolving. The cylindrical pistons

h, are of such diameters as will allow them respectively to pass freely into recesses i, and the depths of the recesses are such as to permit the cylindrical pistons to recede within the curve of the periphery of the drum-wheel. There are small grooves in the inner part of the chamber ▲, shewn by dots at s, s, int he section fig. 11, leading to the induction and eduction passages, which are designed to prevent the compression and rarification of the steam.

The internal construction of the engine having now been described, its mode of operating will be readily understood, principally by reference to the section, fig. 11.

Steam, of any required pressure, admitted into the engine by the induction passage c, will first occupy the small part of the steam-way marked j, and insinuate itself into the recess i, behind the piston, and it will also force the piston h1, tightly against the opposite side of the recess i, and against the internal periphery of the cylinder, forming at those parts steam-tight junctions. The force of the steam thus acting, will cause the drum-wheel d, to perform part of a revolution until the piston h1, arrives at the situation of 12. By this time, a second piston, as h3, will have been brought into the situation of the piston h1, and will there be acted upon in like manner, and consequently continue the rotation of the drum wheel. When the piston h2, passes the opening of the eduction passage k, the volume of steam which had been acting upon it immediately escapes up the passage k, through the slide valve l, into the eduction pipe m, and thence into the atmosphere or to a condenser.

It may be here remarked, as a consequence of this construction of engine, that the drum wheel, in revolving, causes the cylindrical pistons not only to fall by their gravity against the internal periphery of the cylinder, but to be thrown outward by the centrifugal force, and thereby

be kept at all times in contact with the surface of the cylinder, which is further aided by the pressure of the steam acting against the pistons, which are thereby kept steamtight.

The valve 1, 1, and eduction steam-pipe k, are covered, as seen in fig. 11, with some material, which is a bad conductor of heat, such as air, saw-dust, felt, wood, asbestos, or other suitable substance. The object of thus clothing this part of the engine, is for the purpose of preventing the eduction steam from carrying off the heat, or reducing the temperature of the induction steam passing from the boiler through the valve-box into the cylinder. For, unless some such precaution is taken, it will be found, that the temperature of the induction steam will become reduced.

In reciprocating engines, both sides of the piston and the internal ends of the cylinder may be similarly clothed for a like purpose.

To reverse the action of the engine, which is often required when employed for locomotive purposes, the screwshaft n, must be turned by means of the handle, and thus the valve will be brought into the position shewn by dots, when the steam will be supplied to the cylinder on the opposite side through the pipe k, and make its exit through the pipe c, in the contrary direction of the arrows, thus reversing the motion of the engine.

The bosses g, g, and the bearings f, f, are constructed in the manner shewn in fig. 1. e, represents the main shaft of the engine, surrounded by a sufficient number of small loose rollers without axles, all accurately turned to one size. These rollers are placed nearly in contact completely round the main shaft, and prevented from escaping by end plates, which are properly secured, as seen in fig. 10, and the joint is made perfectly steam-tight, by means of hempen or metallic packing.