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TAYLOR AND DAVIS'S ROTARY STEAM

ENGINE.

Sir,-Contemporary journals have of late been rife with an account of a new mechanical wonder that has made its appearance in the shape of a steamengine, possessing (so say the accounts) unrivalled power, portability, and cheap

ness.

The accounts of this new wonder have hitherto been without the aid of diagram or illustration. At all times it is a matter of considerable difficulty to represent by words alone, the mechanical construction and action of any apparatus however simple its arrangement may be. In this particular instance, however, the description alone would appear to draw largely upon the credulity of the public, and its obscurity of meaning has reminded some of the less credulous, of the story of the old lady who shewed so much anxiety to furnish her dwelling with curious and complicated articles of furniture-giving as general directions to her mechanist that all was to be accomplished" somehow by means of a screw." The inventor of the present notable contrivance appears to have been fully impressed with the wonder-working operations of the "screw," and has accordingly produced an apparatus which probably has not its equal for eccentricity of motion or screw-like evolutions. The following is the non-illustrated description, assisted in the present instance by the diagram accompanying this communication, which it is hoped will help to throw a little more light upon this new-born of science :

"At the British Alkali works, Stoke Prior, near Bromsgrove, a steam-engine has been invented by a labouring mechanic, and is daily in full operation, which will certainly supersede every other now in use, and that, too, in a very short period of time; as the simplicity of its construction, the smallness of its size, and the almost nothingness of its cost, will necessarily bring it speedily into notice among all persons whose business may require the aid of so useful an auxillary. Its size is not more than twice that of a man's hat, and the expense of a five horse power will not exceed in cost half a score pounds. Its form is cylindrical being about eighteen inches diameter and twenty-two deep. The steam is admitted through a hole in a hollow circular belt (attached to a wall) upon which it revolves, and works it by a diagonal action, against an upright piston, being forced out by pressure of a diagonal plate, which divides the inte

rior into two portions. The rotary action is beautifully managed by means of a perfectly spherical steam-tight joint, at the end of a fixed inclined arm, towards which joint the upper and lower surfaces of the interior part of the cylinder are made to slope, after the form of the exterior of an hour glass. Upon these the diagonal plate performs its revolutions, such movement being permitted through an opening (from the circumference to the centre), equal in width to the thickness of the before named upright piston, up and down the sides of which it continually works. In the centre of the bottom of the cylinder is fixed a shaft, having attached to it a wheel which communicates the motion that may be required; and this is all the machinery of which it consists."

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One would imagine that the editor of the journal was making merry at the expense of the "labouring mechanic," or at any rate gving a satirical fillip to the inventor, when he says. that" our scientific friends will not consider us too bold in asserting that this invention will speedily revolutionize the whole system in this department of mechanics." When and how this will be effected I leave to the readers of the Mechanics' Magazine to determine. For one, I must confess a little scepticism on the subject. In the absence of all practical data connected with the operation of this engine, we may at least suggest that friction is not altogether dispensed with, and that the rotary action so beautifully managed" with the spherical" steam-tight joint" is a very clumsy way of accomplishing what has hitherto been effected without that tendency to torsion which would ultimately result from its present mode of application. Appearances indicate this engine to be of the kind usually denominated " high pressure." The

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quantity of steam used, its pressure, work employed in, form of boiler, quantity of fuel used, quality of ditto, form and packing of piston, number of revolutions per minute, &c. &c., are so many important points of information that require to be ascertained, to do full justice to the ingenuity of the inventor. As matters stand at present, Messrs. Boulton and Watts, Mandslay's, Seaward's, Hall's, &c. &c., respective steam engine arrangements, are not likely to be affected by the revolutionary assertions of the Engineer's Journal.

*Civil Engineer and Architect's Journal for March 1838.

References to the Diagram.—A, outer case of cylinder; B, steam chamber (or cylinder); C, flanges to connect outer case; D, ball and socket joint; E, stuffing box &c.; F, connecting rod to crank; G, the crank; H, crank shaft; I, plummer blocks, &c.; K, standard for ditto; L, M, steam passages. Na disc fitting into the cylinder A; O, a quadrantshaped piston, attached to the inner surface of the cylinder, the disc N having a slit therein from the rim to the centre, to allow it to reciprocate upon this quadrant. The steam is alternately brought

to the upper and under surfaces of the disc N, thereby producing a circular conical motion of the disc, and turning the crank G.

Your, &c.

CHRIS. DAVY.

Note. The diagram is intended merely to show the form and operation of the engine-possibly there may be some slight inaccuracies, but they cannot be of sufficient importance to effect the merits of the invention. The drawing has been made from recollection.-C. D.

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Sir, This invention, I believe has been patented some time; it is very simple, and likely to be effective, and the only thing that can in any shape militate against it (in my humble opinion), is the possibility of the combined friction of the two cocks, and the rod working in the stuffing-box, rendering so sluggish the action of the float, as to defeat the object of the invention. In the above drawing, P shows a portion of the boiler; c, a water reservoir, made steam tight; a, a pipe, through which c is supplied

with water, having a valve opening inwards, at L; g is a steam pipe, extending from the boiler, to nearly the top of the close vessel c, and s is a water-pipe extending from the bottom of the close vessel to the interior of the boiler. In both these pipes, are stop cocks R and T, with levers extending to Y, by which they are opened and closed. In these levers are two longitudinal slits, for the reception of a pin, fixed in a rod, extending from the float H, through a stuffingbox, in the top of the boiler. Now,

when the water in the boiler has evaporated, and its surface descended, the weight of the float brings down the levers to the position represented; the cocks will then be opened, and the steam will rise through the pipe g, by which the pressure will be equalized in the boiler P, and the supply vessel c, and and water will descend through s, till its surface in the boiler, rises sufficiently high to raise the float, and shut the two cocks, and then the condensation of steam in c, will cause a partial vacuum, permitting a fresh dose of water to pass through T into the feed vessel.

I remain, your obedient servant,
RICHARD EVANS.

Swansea, Dec. 18, 1837.

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Mr. Seaward fairly met my claim after having condescended to notice it, by proving his priority of invention, it would have been unnecessary to have occupied your valuable pages with another word on the subject; but instead of doing so, Mr. Seaward commences his observations by endeavouring to implicate me in falsehood by most positively deny" ing that he had ever any conversation with me on the subject of the valves. Now, although it is a matter of no moment to the point in dispute, whether I had ever any conversation with him or not, yet, I again declare most distinctly, that the conversation alluded to in my letter with Mr. Samuel Seaward, occurred in Messrs. Seaward's office; and if it were at all necessary I can perhaps refresh Mr. Seaward's memory with his reply to me, nearly word for word. With regard to of Messrs. Seaward's foremen❞ not having asked or accompanied me on board the "Emerald" at the time alluded to in my letter, I can only say, that it is untrue. Messrs. Seaward had more than one foreman in 1834, I certainly cannot name the man who accompanied me on board, but I feel pretty confident that

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should this meet his eye he will not hesitate to avow it.

If Mr. S. had read my letter with a little more attention than he appears to have done, he would have seen that what I therein stated about the Lords of the Admiralty and Mr. Brunton, was given as I received it from the person who accompanied me on board; I did not represent as a fact that those gentlemen were on board the "Emerald" at any particular time, and I have reason to believe myself in error in stating that Mr. Ewart name was mentioned. Indeed, I find upon inquiry in the proper quarter, that Mr. Ewart was not connected with the government service at the period alluded to, and I am sorry this gentleman's name should have been thus inadvertently introduced. It was Mr. Kingston the engineer of Woolwich, and Mr. Brunton who were on board together; and it was owing to the favourable report of Mr. Kingston that the double nosles were introduced into the service of the admiralty.

My communication contains no allusion to the period at which Mr. Seaward applied for his patent; indeed it is perfectly immaterial to the question; but the first publication of Mr. Seaward's invention, or at least so far as my knowledge of it extends, is to be traced to its use on board the "Emerald" which vessel commenced plying on the river in June 1834, four months previous, I think, to the date of Mr. Seaward's patent.

Mr. Seaward expresses astonishment that I should have "waited till the present day to put forth my claim." I can assure Mr. Seaward, I should not even now have done so, had not several of my friends plainly hinted that any further silence might be construed to my disadvantage, in reference to the part I took in introducing the plan. Nearly three years ago, I received a letter from a gentleman well-known in the scientific world directing my attention to Mr. Seaward's circulars respecting these nosles, and advising me to publish my claim to the invention.

In no part of my letter have I stated that Mr. Seaward was not the inventor of the nosles of which he is patentee, I left it for Mr. Seaward to shew his claim to priority in the invention if he thought proper; and perhaps he may now consider he has done so by having informed

your readers that he thought of it in Cornwall twelve years ago, and that a full description of the plan is contained in his journal dated May 1830; all this I cannot dispute; the object of my letter was simply to prove, that I had anticipated Messrs. Seaward in pointing out the use and advantages of double slide valves, not to "one or two individuals only" as Mr. Seaward represents it, but to the directors of two public companies, and that I had devoted a good deal of time in endeavouring to introduce their use in marine engines, two years before the date of Mr. Seaward's patent, facts which Mr. S. has not attempted to disprove. It was by mere accident only that these valves were not in operation in a pair of engines of 220 horse power between five and six years ago. What in that case may I ask, would have become of Mr. Seaward's claim? Why, I should have been told perhaps that I had peeped into his journal of 1830!

Hoping that the introduction of double slide valves into Cornwall may fully realize Mr. Seaward's expectations, and remove all the imperfections and difficulties he complains of as arising from the use of double beat valves, I remain, Sir,

Yours respectfully,
FRANCIS HUMPHREYS.

Dartford, April 18, 1838.

ANALYSIS OF HARPER AND JOYCE'S PATENT FUEL.

Sir,-The increasing estimation in which the Mechanics' Magazine is held, and the great benefit it has conferred, and is conferring on the scientific world in the improvement of the arts and sciences, induces me to trouble you with a few lines on Messrs. Harper and Joyce's stove. A few evenings ago I experienced the gratification of witnessing a series of experiments on the material used in this stove as fuel, and which has been kept so profound a secret. The chemical operations were conducted by the hand of a master, and according both to the analytic and synthetic methods. Before proceeding farther, however, it may be as well for the information of the general reader to explain what these methods are. The first is analysis or decomposition; the second synthesis or composition. In analysis the parts of which

bodies are composed are separated from each other thus, if we reduce cinnabar which is composed of sulphur and mercury, and exhibit these two bodies in a separate state, we say we have decomposed or analyzed cinnabar. But if on the contrary, several bodies be mixed together and a new substance be produced, the process is then termed chemical composition or synthesis; thus if by fusion or sublimation we combine mercury with sulphur and produce cinnabar, the operation is termed chemical composition by synthesis. This explanation will clear the way for the following outline: -On the evening in question the experimenter or manipulator before commencing his operations began by enumerating the gases which experience has proved to be destructive to animal life; he extracted these gases from solid matter by chemical affinities; alighted wax taper when plunged into these gases was instantly extinguished and animal life expired in a few seconds when immersed in them. After these various phenomena had been exhibited, the experimenter showed how by certain tests the presence of these various deleterious gases might be detected, and also how the quantity of these gases contained in any given quantity of a solid material, might be ascertained. The gas I believe (with the exception of oxygen) which is most abundant in nature, is the carbonic acid gas, which when inhaled by animals almost immediately destroys life, and to this gas the experimenter particularly directed his attention. The material used as fuel in Joyce's stove was examined with great care and judgment, with the view of ascertaining its composition; it having been currently reported that this fuel was gifted with its extraordinary virtues by means of two, if not three new ingredients, or new combinations of old ingredients, that in fact it was charcoal combined with some substances which caused an immense volume of caloric to be thrown out when in a state of combustion. Now the carbonic acid with which charcoal is known to abound, and which is so destructive to animal life when extricated by combustion, was said to be neutralised by these hitherto unknown or newly combined ingredients. The experimenter having subjected the fuel used in Joyce's stove to analysis, proved it to be incontestibly nothing more nor

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