rior tube, termed the "water line" in ali the vessels The steam generated in this first vessel, and the wate that remains, is next forced through the connecting pipe into the second vessel a 2; from thence successively through a 3, a 4, and a 5, then into the "steamometer" b, by the end always open; and from thence by the eduction pipe g into the engine. The water injected into the pump at c, has thus, in its passage from the pump to the engine, passed in a thin sheet over a heated surface of many thousand inches, and, consequently, the steam may be generated of a very high pressure with extraordinary rapidity, -The foregoing arrangement, from disposing of the water in "thin sheets," may seem at first to promise great advantages, but an inspection of fig. 2, will, we think, convince the reader, that the greater portion of the heat passes up the chimney, instead of into the water. The complexity of the construction, the liability of deposits, incrustations in the narrow spaces between the cylinders, and the difficulty of cleaning them out, are likewise objections which, we think, will prevent this apparatus from being successfully used in the generation of steam.

Patent Steam-generating Apparatus, by Joseph Eve, of London. 1825.

The intention of the inventor of this apparatus, and the advantages claimed by him as resulting from its arrangements, are the preserving of a constant circulation or current of water throughout the tubes, preventing thereby, in a great measure, their oxidation or burning out; by the great strength of small tubes to resist lateral pressure, affording security against bursting; and by the uniform éirculation of the water, rendering but a comparatively small furnace necessary, and the whole apparatus extremely compact. The reader will perceive a great analogy between this invention and that subsequently patented by Mr. Gurney, a description of which is hereafter given. (See Index.)

Figures 1, 2, 3, and 4, exhibit so many different views of the apparatus, including an application of two revol

ving cocks, to supply the waste of water, in lieu of a forcing pump. Fig. 1, is a side elevation; fig. 2, a vertical section; fig. 3, a front end view; fig. 4, a back end view; the same letters of reference apply to all the figures. a represents the lower conduit pipe; b the steam receiver; c c are two pipes, in which the water descends from the steam receiver to the lower or conduit pipe; dis the dome connected with the steam receiver, from which dome the steam enters into the steam pipe ƒ, and into the pipe e, which latter leads to the safety apparatus. ggg, are ten pipes, which communicate with the lower conduit pipe and the upper pipe, or steam receiver. Fig. 2 represents one of these ten sections in front, the manner in which they are formed, and connected with the two horizontal pipes, which latter are shown in section in this figure; h and i are two valves, the former kept open by its own weight, and the latter floating. With these two valves every section of pipes is provided at its two orifices, where they communicate with the lower conduit and steam-receiving pipe; p p is the fire-grate, over the middle of which the smaller combination of pipes is placed; o o is an ash-pit q is an end piece, which, being screwed into the lower conduit pipe, admits of the latter being cleaned out whenever required. The number of sections and pipes composing each section, and the manner in which the pipes are bent, are arbitrary.

The apparatus is filled with water through the orifice o, shown in fig. 1. The heat of the furnace causes the water to circulate through the tubes, thereby preventing the steam from driving the water out of them, and the rapid oxidation of the metal. The tubes are from one to two inches in diameter, and from an eighth to a quarter of an inch thick; tubes of these dimensions are sufficiently strong to bear the force of steam of the highest pressure. The horizontal pipes are 14 inch thick, and 94 inches diameter; the vertical pipes, three quarters of an inch thick, and 4 inches diameter.

The valves h and i, attached to the orifices of each of the section pipes, where they enter into the horizontal

tubes, are placed there in case of a rupture in one of the sections to which they belong; in which case, the unbalanced pressure of steam would force the water so rapidly into the particular section that was ruptured, as to cause the valves to close, thereby preventing any waste of steam, and detaching the ruptured section from the rest of the generator. By this arrangement, the engine need not be stopped, but would only lose so much of its power as the proportion of one section to the remaining sound ones would be. The two large vertical, as well as the two large horizontal tubes, are imbedded in brick-work, and the sections only are exposed to the heat of the fire; therefore no steam will be formed or generated in the former, while the action of the fire will cause the steam and water to ascend rapidly through the small pipes into the steam receiver, while the water therein, being heavier than the water combined with steam in the smaller pipes, will descend through the vertical tubes into the lower conduit tube, thereby causing a continual circulation through all the tubes; the steam will of course accumulate at the top, and through the dome find its way to the steam pipe and safety apparatus. In case the circulation should be too rapid, and to prevent the water being forced into the steam pipe before it descends again through the vertical pipes, a piece of sheet-iron is placed, perforated with small holes similar to a strainer, in the middle of the steam receiver, from end to end. The small pipes in the sections have the peculiar serpentine form given to them, in order to enable the steam to rise to the top more rapidly than the water.

These boilers are supplied with water by means of revolving cocks, as before mentioned, in lieu of the forcing pump, as shewn in fig. 4, where two cocks are represented; n is a vessel filled with water, of any convenient shape; one side of which vessel is near the furnace, so as to keep the water warm; this vessel is connected with the generator through a tube entering at o, which is shown in section in the drawing; this tube has two revolving cocks, k and i, with a chamber between them. The cocks are

made to revolve equally by cog-wheels gearing into each other; so that if cock k be open towards the water reservoir, cock i will be closed towards the tube leading to the generator.

The chamber between the cocks will therefore be filled with water through cock k, by that time cock k closes and i opens towards the generator; the water in the chamber will then descend through o into the generator, by its own gravity, and its place be occupied in the chamber by steam from the generator; cock k opens again towards the chamber, and i is closed towards the generator. The steam in the chamber will be condensed by the water now entering, or escape into the water reservoir n; this revclution goes on continually. If water be presented by cock i to the generator, and the said generator should be sufficiently full, in such a case the water will not be received, but remains in the chamber until part or the whole is wanted, the cocks constantly revolving. By this arrangement, the water can be kept constantly at the desired height.

In this apparatus, Mr. Eve has introduced some very novel and interesting combinations, among which, the following seem to be deserving of notice. First, his me thod of keeping the water circulating throughout the pipes, requiring, in consequence, but a comparatively small furnace, and, by the compactness of the whole apparatus, rendering it suitable to locomotive purposes; secondly, in the invention of the revolving cocks, by which the boiler is fed without loss of steam or power; for it will be observed, that the heat of the steam in the chamber between the cocks is not lost, which, although condensed, enters into the water chambern; thirdly, the method of cutting off the damaged portion of the tubes, in case of rupture in any of the sections. The mode of communicating the heat laterally is not good, but, under some modifications, it might be made a very efficient apparatus.