On the Smelting of Copper-ores. Stockholm, 1766.

On the Uses of the Stones which are furnished by the Quarries of Sweden.

1771.

On the Resources of different Provinces of Sweden. 1773. Tables of the Population and Manufactures of Westro-Bothnia. Stockholm, 1801.

Essay of a Mineralogical Description of Lapland and Westro Bothnia. Stockholm, 1801.

Lastly, Mineralogical Maps of the principal Provinces of the South of Sweden.

ART. XXII.-Account of Mr Perkins' method of applying his New Method of Generating Steam to the Boilers of ordinary Steam-Engines.

HAVING in our last Number given a very full, and we trust

perspicuous, account of Mr Perkins' new Steam-Engine, we shall now proceed to lay before the reader Mr Perkins' own account of his method of applying the new principle to steam-engines of the old construction. This account is taken from the specification of his patent, which is now open to the inspection of the public.

In order, however, that a correct idea may be formed of the original principle itself, we shall prefix Mr Perkins' own account of the generator, although we have already given a general description of it in our last Number.

"Plate IX. Fig. 1. represents the general construction of the apparatus; a, a, a, is the generator shewn in section. It is a strong cylindrical vessel, made of metal, about three inches thick in every part, which may be a guide to the comparative dimensions of the other parts of the apparatus. This vessel is to be filled with water, and heated by a furnace circumscribing it. On the top of the generator there is an escape-valve b, pressed down by the weighted lever c, the pressure being adjustable by the shifting of the weight. The valve opens to to the steam-pipe d, which is to be supposed as proceeding to the working piston of the engine. The lateral pipe e, extending from the generator, is merely for the purpose of safety; and at

the end of it there is an apparatus f, attached, by which the pressure is indicated; g, is the feeding or injecting pipe leading from the forcing pump h, which may be worked by a connection to the moving part of the engine.

"In order to generate steam, the vessel a must be filled with water, or other fluid or fluids, from the pump h, and heated by a furnace, or otherwise; the steam, or escape-valve b, being loaded by means of a weight, with a pressure greater than the expansive force of the steam, to be generated from such water, or other fluid or fluids, at the time of its generation. When the water, or other fluid or fluids, in the generator, has attained the necessary degree of heat, say from 400 to 500 degrees of Fahrenheit, more or less, an additional quantity of water, or other fluid or fluids, is pumped into the generator, sufficient to force out a portion of that already heated in the generator from under the weighted-valve b, into the steam-pipe d, where it instantly becomes steam.

"An enlarged representation of the valve, and its seat, is shewn in the section, Fig. 2. The valve is a spherical bulb, falling into a concave seat, in the lower part of the square chamber; the upper part of the valve is a cylindrical rod, upon the top of which the weight of the pressing-lever is exerted; the lower part of the valve is a triangular stem, sliding up and down in the cylindrical passage. When the additional quantity of water is injected into the generator, by means of the force-pump as described, the bulb of the valve rises from its seat, and a corresponding quantity of heated water passes up between the cylindrical passage and the sides of the triangular stem, into the square chamber, where the pressure, no longer operating upon that portion of the water, it immediately becomes steam, and passes forward through the steam-pipe to the working cylinder.

:

"In order that the operations may be renewed, and continued regularly, I make use of an adjusting weight on the handle of the pump i, which is a small single-stroke forcingpump, with a weight performing the office of an air-vessel. At the end of the pump-handle is a chain m, which I connect with a simple crank movement, and thus, by a corresponding adjustment between the weighted steam, or escape-valve b, the throttle

valve, (which it is not thought necessary to shew in this drawing) and the weight on the handle of the pump i, a certain quantity of water is forced into the generator, at every stroke of the pump, and a corresponding quantity forced from under the weighted valve b, to become steam.

"These principles may be modified and applied to the boilers of ordinary steam-engines, a mode of adopting which is shewn in Fig. 3. The invention is here represented under another form, and differently employed, being a plan for heating the water of an ordinary engine-boiler, with a view, principally, to save fuel: %, is a tube communicating with the ordinary steam-boiler; a, a, is the generator, a cylindrical metallic vessel, of which there may be several connected together; these are filled with water as above described, having the furnaces y, y, under them; b is the escape-valve through which the heated water passes; c, is the weighted lever pressing down the valve with the required force: d, is the chamber and pipe, in which the heated water that escapes through the valve becomes steam, and thence passes through the tube %, into the boiler. This boiler (of a cylindrical form with spherical ends) is proposed to be inclosed within a cask or other vessel, and surrounded with pounded charcoal, which material being a very imperfect conductor of heat, is particularly well calculated to preserve the heat of the water and steam within the boiler ; e, is a pipe leading from the generator, which is also filled with the heated water; and at the lower end of this pipe there is an apparatus f, for ascertaining the pressure of the fluid within the generator. This fluid, by exerting its force at the lower end of the pipe e, against the lever connected to a weighing-machine, causes the index to point out upon the graduated dial-plate the number of atmospheres under which the steam is generated. The pipe e, being in substance considerably thinner than any other part of the apparatus, is intended to give way, in the event of the pressure within the generator being accidentally raised to a dangerous height; the consequence of which would be, that the pipe e would open, and the steam blow out through the fissure, without the possibility of producing any injury; g, is the pipe through which the water is injected by the pump h,

from the reservoir to the generator; i, represents the flue or chimney, from the furnaces below.

"The continued passage of high pressure steam (generated as above) through the tube %, heats the water, which ọccupies about half the interior of the boiler, and by that means a sufficient quantity of steam may be produced in the boiler for working an engine of the ordinary construction, and with a very important saving in the quantity of fuel, compared to what would be consumed, to effect the same purpose, by any other plans heretofore adopted."

"Now, whereas the materials of which my said improvements are constructed, and the exact proportions of the relative parts, are not subjects for which I hereby claim exclusive privilege, though I have described those materials and proportions which I have found most useful; neither do I hereby claim exclusive privilege for the peculiar forms of the various mechanical agents which I employ, but only for a combination of such and the like agents as will produce the said improvements, the nature of which is herein before declared, and for which a claim to exclusive privilege is hereinafter made. And whereas, I have only represented in my said drawings annexed, such parts of a steamengine as comprise my said improvements, the various modes of applying such said improvements, by means of the steampipe being too well known to require particular description here. And whereas, my said generator may be heated by a variety of known furnaces, I have not described any one in particular, but the one I have used and found to be the best is one of the cupola kind, fed by a blast. And whereas, I have described in my said drawing, Fig. 1, a safety-pipe and indicator, and a forcing-pump, neither of which are in themselves new, but which apparatuses, or similar ones, constitute a combination necessary to my said improvements, and are inserted as such; I therefore hereby claim exclusive privilege for the following improvements only: that is to say, first-for heating water or other fluid or fluids, for the purpose of generating steam for steam-engines, in a vessel or vessels, kept (during such process of heating) full of such water or other fluid or fluids, and under a pressure greater than the expansive force of the

steam to be generated from such water or other fluid or fluids, at the time of its generation.

"Secondly,-For causing such water, or other fluid or fluids, so heated as aforesaid, to escape from under the said pressure, and pass at once from the generator into the steam-pipe, where it becomes steam or vapour, and in that form may pass thence to the cylinder, or to any other situation connected with a steamengine, without the necessary intervention of any steam-chamber, or other reservoir of steam.

"Thirdly,-For the manner of causing such water or other fluid or fluids to escape as aforesaid, that is to say, by forcing other water or fluid or other fluids into the generator, until the pressure against the steam-valve shall cause it to rise, the valve being so loaded as not to rise, except by means of such extra pressure as aforesaid.

"Fourthly,-For the general application of such water, or other fluid or fluids, so heated as aforesaid, and of the steam or vapour generated thereby; whether such steam or vapour be employed through a steam-pipe without a steam-chamber or reservoir to act immediately on the piston, or to be collected in a reservoir or steam-chamber, and thence to act on the piston, or only for heating water to generate other steam, or for any other purpose or purposes whatsoever, provided always, that such general application as aforesaid be for the steam-engines."

purposes

of

The Editor of the London Journal of Arts, from which we have taken the preceding specification, informs us, that the mode of applying this principle to a variety of operations in which heating may be requisite, is embraced by a second patent to be specified in November, and that the mechanical construction of the working parts of the engine will be explained in the specification of the third patent, which will be enrolled in December.

The same writer informs us, that several of the new engines which have been ordered, are at present constructing; and, particularly, that an engine of about 80-horse power, for the purposes of steam navigation, is in considerable forwardness, and will probably be in operation between London and Margate before the end of the present summer.