338 CURTIS'S CHIMNEY-HOOD AND ASH-PAN FOR LOCOMOTIVE-ENGINES. CURTIS'S CHIMNEY-HOOD AND ASH-PAN FOR LOCOMOTIVE-ENGINES. Sir, I send you a drawing and description of my chimney-hood and ashpan for locomotive-engines, as used on the London and Greenwich Railway, and shall feel obliged by your insertion of the same in your valuable pages. The Hood.-The chimney of the engine is covered with a dome, which projects the steam and heated air escaping into the atmosphere upon a surface of water contained in the receiver or outer vessel, so that any sparks or other matter ejected from the chimney must necessarily be received in the water, and consequently extinguished. The condensation of the steam, together with the priming of the boiler, supply sufficient water to keep the bottom of the receiver always covered; and for the purpose of carrying off any excess of water, a small tube is fixed to the bottom of the receiver, and this pipe stands up about 1 of an inch, so that a plate of water of 14 inch deep is always ensured. The pipe enters the chimney and forms an elbow, which elbow also is always full of water, so that no fire can possibly pass through it. It is my intention eventually to form the dome double, and to pump up the cold water, which will be thus heated by the waste steam, and then to pump this heated water into the boiler, thus converting the apparatus into a feed head. I find a space all round of about four inches sufficient for the passage of the steam, &c. I have put this invention to the most severe tests I could devise, but could never force a spark from the chimney. The engine runs freer and faster than with the gauge, the draught is unimpaired, the apparatus is cheap and simple, and absolutely safe. Description of Engravings. Fig. 1 is a section, and fig. 2 an elevation of the hood: a, chimney; b, receiver, containing water; c, dome or hood; d, bent tube; the curved arrows show the path of the steam, air, &c. The ash-pan is a box of sheet-iron suspended under the fire, and water-tight, so that the water] filtering through the fire-box a is received into it. The pan is about eight inches deep, and the sides rise above the fire-box about three inches all round, so that the dust in the act of falling is not blown away during the progress of the engine, or by the wind, and being received into water is, of course, immediately extinguished, while the water is evaporised; and the vapour not only prevents the coke from clinkering on the bars, but materially assists the combustion. The box is open all round and behind about eight inches, thus providing abundant area for the passage of the air to the fire. It is suspended behind by a joint to the framing, and before by a chain which coils round the axle of the hand-wheel f, so that when the engineer wishes to discharge the ashes, or rake the fire-bars, he merely lets go the wheel, when the pan falls down, describing the curve shown by the dotted line. Description of Engravings. Fig. 3 is a section, and fig. 4 an elevation of ash-pan and part of the boiler: a, fire-box; b, boiler; c, fire-bars; d, ash-pan, containing water; e, hinge of ditto; f, hand-wheel; g, chain by which the pan is suspended. The curved arrows indicate the path of the air. Your most obedient servant, Deptford, August 6, 1836. MR. SYMINGTON'S REPLY TO MR. HOWARD. Sir, Mr. Howard's communication contained in your last Number betrays such evident marks of being got up in haste, that I am certain by this time even Mr. Howard himself will scarcely deem it worthy of serious refutation. I shall, therefore, content myself with referring such parties as may take an interest in the question to the drawings accompanying Mr. Howard's specification and to those in my circulars, where it will be found the difference between the two inventions is any thing but "immaterial." In one part of his letter Mr. Howard says, "I may add, that the process (his, I suppose) answers completely;" in reference to which I have merely to observe, that not being aware how far Mr. Howard's notions of completeness extend, I will not, for a moment, think of contradicting him, but briefly remind him, that the more simple any useful invention is, so much the nearer is it to perfection. Bearing this fact in mind, I fearlessly leave it to Mr. Howard's own judgment, whether he will venture to say that his invention is possessed of the greater simplicity. THE ELECTRICAL THEORY OF THE UNIVERSE. One thing more, and I leave Mr. Howard calmly to reflect, whether it was fair to deal in assertions which he can neither substantiate, nor has taken due pains to ascertain to be wellfounded: although such assertions might produce an unfavourable impression regarding the conduct of an individual to whom he was a stranger. He has ventured to assert, that I saw his process in operation at the King and Queen Iron-Works, Rotherhithe, upwards of two years ago; but this assertion is as erroneous as that he has anticipated me in my plan of condensation, for I can and do most positively affirm, that during the whole course of my life I never saw his principle, or method, or process, either at work or at rest; neither did I ever set foot within the walls of the King and Queen Tron-Works, Rotherhithe. much for hasty conjecture! Unless Mr. Howard can disprove my positive affirmation, surely he cannot but regret having so phrased his assertion, as that it might tend to create suspicions of my being unprincipled enough to visit him for the purpose of surreptitiously depriving him of his plan of condensation. So Trusting you will oblige me by giving this insertion, I have the honour to remain, Sir, 1, King William-street, Lon ion Bridge, THE ELECTRICAL THEORY OF THE UNIVERSE. Sir, I am somewhat inclined to think that your correspondent, Ursa Major, and your humbler servant, Kinclaven, are old acquaintances; however, be that as it may. It appeared from his first article on the Electrical Theory of the Universe, that he was a waverer between the Newtonian and Mackintoshian theory; but, from his last, he appears to be about three-fourths charged with electrical fluid, and no doubt one lecture more will make him brim-full. He informs me that he is no stranger to the demonstrations that have been given on the general law of the tides by all the great mathematicians (La Place included) who have lived since the days of Newton; and he very modestly requires me translate their demonstrations into the language of common sense." That is, to 339 in plain English, he (Ursa Major) having Mr. Mackintosh informs us (No. 645) that his theory is in accordance with Kepler's laws. And again, in No. 655, he states that our earth must at one time have been attended by at least five moons. We shall see how this agrees with one of Kepler's laws, namely, that the squares of the periodic times are as the cubes of the mean distances from the sun. hence = Let t and T be the periodic times of two planets, d and D their mean distances, v and V their angular velocities. Then, by Kepler's law, t2: T2: d3: D3 ; also, from the laws of central forces, t2= d2 D2 d2 D2 and T2 :: d3:D3, v2 V2, v2 V2 from which it follows, that do DV2. Again, Mr. Mackintosh informs us, that the paths of all the planets are becoming nearer and nearer into circular orbits, and -ultimately they will all be whirled into the body of the sun. Supposing this to be the case with the planet whose present mean distance from the sun we have designated by the symbol d; then when that event takes place, do.'. dv2 = o, but when d ceases to exist so must v2 .*. v2o; also since dv DV2, therefore DV2 o, hence one of the factors D or V2, or both, must be o; if D= o, then the angular velocity V ceases .', V2 = 0. Again, when Vo, it follows, either from the laws of gravitation or the electrical theory, that if D is noto, it will quickly be so, for the planet then would be only acted upon by a centripetal force; and it would be contrary to either theory to suppose that the second planet (when Vo), like Mahomet's coffin, could be suspended in mid-heaven. It therefore follows, that if Mr. Mackintosh's new theory is in accordance with the law of Kepler-when one planet is destroyed, all the rest will almost immediately share the same fate-the same reasoning may be applied to the case of the five supposed moons, but as we are Ursa Major, I presume, has not read Professor Airy's little work entitled "Gravitation," which was noticed in the Mechanics' Magazine more than a year ago. I would recommend him to read it, as it is well adapted for those who are not deeply read in mathematical science. MR. DICKSON'S REPLY TO THE CORNISH ENGINEERS. Sir,-In the observations (No. 675) on my letter to you (in No. 669), the writer begins with the verb to be, or the difference between the word was and is. So little is this difference, that this was and is is not the word that I alluded to, for it was and is the application of the definite article the to the noun nursery (in place of the indefinite a), which intimated that Cornwall was and is the only nursery for steam-engines. I assure you, sir, I had and have no wish to offend any one, either in word or deed; besides, I am not the only person who have taken notice of the glaring improbabilities set forth with respect to Cornish steam-engine work. The writer complains of my not addressing myself to him as taking upon himself to be the champion of the Cornish engineers; but this I must decline, because my remarks appertain generally to so many persons whose names have been attached to the accounts of different performances for several years past. Mr. Enys has not given any other reason for the increase of duty, but repeated that it was and is from the improved pit-work and their complete system of clothing, together with the use of high steam used expansively, that they have been enabled to do so much with a bushel of coal. Now all these they have had, now have, and shall have in future; nevertheless, I repeat my protest with all that accompanies it in my letter, dated May 25, 1836. THE CORNISH ENGINEERS. 66 they only are in difficulties, and although they regard with the utmost apathy the opinions or assertions of engineers of other parts of the kingdom," perhaps the public will not do so, because controversy has often been the means of arriving nearer to the truth, and this was and is the reason why I wish them to begin their calculations again, taking truth or facts as the foundation, to depart from the unit, and in place of a hundred millions raised one foot high, let us have a million of pounds weight raised a hundred feet high, &c. The writer also states, that at certain mines from a comparison of two different years there was a great difference in the quantity of coal paid for, and that "the water delivered was assumed to be the same in both years.' Now this is rather too bad-even to dis-: card calculation, as well as their admitted "well-known errors," which have as sisted them in showing their hundred and odd millions. Whatever erroneous calculations cannot do, assumptions of course will easily accomplish. Every enginee worker knows that his engine (if in good order) will only consume coal in proportion to the work done; and I presume it will not be denied that most of the water raised from mines first descends from the surface of the earth in spite of the precautions used to prevent it; consequently a rainy season often makes a great difference. In some districts there are mines to be found where the water is drawn from about three-fourths of the depth, while in the lower quarter scarcely any water is found. Suppose, for instance, any of the clever men, since Mr. Watt, had been able to enforce the payment of a portion of the savings that has been effected, would the proprietors have quietly submitted all this time to the accounts being all on one side ? Some that I have spoken to, say no; and farther, that we should never have heard of their ten-times-ten millions, and so forth, if there had been any opposite interest to contend with. The writer speaks of the difficulty of measuring water from dif ferent levels; but from the average surface of the water in the sump, or place from which the pump draws it to the point of delivery, I believe is what ought to be taken, and they cannot all be such cramped holes in Cornwall, that a couple of cisterns cannot be put or formed in the strata, each to hold a few minutes or hours' delivery of the water from the FALLACY OF JONES'S MERCURIAL STEAM-WHEEL, pumps. This once done and attended to, no algebra, and very little arithmetic, would be wanted to set all contentions at rest. I am glad, however, that I have not interfered with the mode of showing the great increase of duty; they are at liberty to generate their steam as cheap as they can, to raise it as high as they choose, and afterwards to allow it to expand to the uttermost point, and at last condense it in any way, being always clothed in their own garments, with all these appliances, if they can prove what they have asserted, it would be a great national benefit, an honour to Cornwall, and I should be satisfied with being the means of causing others to perform a meritorious task. With these sentiments I leave this subject in the hands of those to whom it belongs; and when these proofs are forthcoming, they will of course be published in the Mechanics' Magazine. Your obedient servant, 9, Charlotte-street, Blackfriars-road, FALLACY OF JONES'S MERCURIAL STEAM WHEEL. "Oh wonders, sure, will never cease, Sir, I have lately commenced taking in your periodical, and from the excellent articles I have observed in it, I have regretted that I did not begin at an earlier period. I have particularly noticed the readiness you manifest to give publicity to any remarks on any inventions at all calculated to forward the interests of mechanical science in the world; and as I apprehend your columns are equally open for strictures upon such inventions when they are not valuable, I have troubled you with a remark or two upon one, I perceive, in your last Number, viz. "Jones's rotary mercurial steam-wheel," which is stated there to possess some marvellous advantages over the common steam-engine; indeed, I was induced to look at it more closely than I otherwise should have done, by observing towards the end of the article the startling assertion (startling, at least, as I think it must be to all who have been accustomed to take the acknowledged rules of mechanics as their guide), that this wonderful discovery completely overturns the old and absurd notion, that to produce a 341 certain effect an equal power must be applied in some shape or other; or, as Mr. Jones expresses it, "if we wish to raise five tons at one end of the beam, a corresponding pressure must be made on the other end or piston ;" and this notion, I say, has been completely exploded; for now we have only to raise 112lbs. to increase the mechanical effect nearly sixteen times. Surely, Mr. Editor, this invention must put to the blush all the paltry little improvements which have been made in steam-engines heretofore; and Messrs. Watt, Trevithick, Murray, Maudslay"cum multis aliis"-with their contemptible 25, 50, or 75 per cent. saving, may now hide their diminished heads, and own themselves out-shone by the resplendent lustre of this new light in mechanical science. Why, even the perpetual motion, that great ignis fatuus of mechanists, has at last been overtaken and fairly run down by "Mr. Jones's rotary steam-wheel;" for it is evident, that if we apply two or three of the "sixteen times power gained" to "raise the 112lbs.," we shall have the remainder at our own disposal "to have and to hold for ever," or at least "so long as the " machine" endureth.' And, sir, can sufficient be said in praise of the philanthropic discoverer of this great "wheel of fortune," who, instead of aggrandising himself by patenting his invention, generously throws it open 'pro bono publico?"-ought he not to be classed with Howard and other individuals who have disinterestedly devoted their time and talents to the public weal, and to have his memory immortalised by a monument (surmounted, I would say, with a figure of Mercury,) in Westminster Abbey ? But, Mr. Editor, lest these honours should be surreptitiously obtained, it may be worth while to inquire whether "Jones's rotary mercurial steam-wheel " do in reality possess such surprising properties as those attributed to it;-I think upon investigation we shall find that it does not-and that in point of fact, it falls woefully behind even the common engine of the old construction. We will pass over the merits or demerits of the steam-wheel as a machine, and suppose it in action, in order that we may examine the calculation of its effect. And here I would observe, that Mr. Jones has committed two great errors; first. in sup |