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ON THE COMBUSTION OF COAL AND COKE, BY C. W. WILLIAMS, ESQ. 23

mean while? Why, a vitiation of the vacuum, in consequence of the evolution of air from the injection water, and other causes. This evolution cannot be rectified by the air-pump during the stroke, and it is of no use for the next; so that, after all, this much-talked of pause may be an evil rather than a benefit, and may arise from a due calculation by the engine-maker, &c., as to the balance of forces.

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ON THE COMBUSTION OF COAL AND COKE -CARBONIC OXIDE, OR COKE GAS. BY C. W. WILLIAMS, ESQ.

[In continuation from page 5.] Sir,-In my last week's contribution to your Magazine I referred to the existence of a combustible gas in furnaces, which had hitherto escaped the attention of practical men- -was denied by manyand doubted by most-outside the laboratory. I allude to carbonic oxide. I transmitted you a letter of a most important character on this subject, setting the whole question at rest, not only as regards the existence of this gas in a useful or available quantity, but of its direct application in the generation of even an intense heat.

Now, the most important considerations, as regards the conversion of this gas to available purposes, relate to the quantity of air to be admitted in effecting its combustion, with the time when and place where such admission is rendered necessary. I will therefore briefly examine these points, as they arise out of the consideration of the constituents of this gas, and the circumstances attending its generation and combustion.

In my treatise On the Combustion of Coal, I considered it of the last importance to dwell on the nature and properties of this "carbonic oxide," and the importance of providing for its combustion. On these points I will, if possible, refer in my next. I will now, for perspicuity sake, and for the better consideration of our subject in a practical point of view, distinguish this gas from the other combustible gases produced in a furnace, by a term which, though chemically it may be objectionable, yet practically will be found to have its value.

I will, then, divide the combustible gases, which are to be converted to the purposes of heat in the furnace, into three classes-First, Bi-carburetted Hydrogen; secondly, Carburetted Hydrogen; and, thirdly, Carbonic Oxide. The first two I will call the coal gases, and the third a coke gas; meaning by the latter term to convey the idea, that the two former are generated in the practical combustion of coal; and that in the process of combustion of the coke, or solid carbonaceous residue of coal, the latter is produced.

Now, with respect to the quantity of air required for the combustion of this carbonic oxide, or coke gas, the weight of carbon which it contains being the same as that which went to the formation of carbonic acid, the quantity of air must necessarily be the same, to provide an equal weight of oxygen. But since the carbonic acid, in its conversion into carbonic oxide in the furnace, has doubled its volume, it follows, that the volume of air required must be in accordance with this chemical transformation of the acid into the oxide. In other words, that each cubic foot of carbonic oxide, taking the carbon thereof at 6, by weight, will require a volume of air, the oxygen of which will be 8, being one-half that required in the generation of carbonic acid; so that, if the solid carbon of a ton of coals requires 240,000 cubic feet to convert it into carbonic acid, the carbonic oxide generated from such, (supposing it all to be so converted, and which is probably the case in large and deep furnaces,) would be 120,000 cubic feet.

With respect to the time when and place where such air should be admitted-it is clear that this should be regulated by the place where the gas is to be encountered-namely, beyond the bridge; inasmuch, as it is only in the passage from the incandescent fuel in the furnace, and after it has escaped from such fuel, that it can be met. This at once neutralizes the erroneous inference arising out of the supposed absence of a combustible gas, when the "coal" gas has all been evolved; and the supposed injurious effect of air, if admitted at such time. Practically, the existence of this gas is unnoticed by engineers, and consequently, the necessary demand for air denied. When, however, we consider that this "coke gas" is generated when

the "coal gas" has ceased to exist; and that its quantity is in proportion to the quantity and incandescence of the ignited fuel on the bars, we shall see that the demand for air for the former will arise in the same rate and degree as that for the latter shall have ceased. Thus this demand is in admirable harmony with nature's uniformity in the supply of air, and relieves us much from the supposed inequality in the demand in furnaces, arising out of an unequal generation of combustible gases. In searching for the reason why the existence of the "coke gas" has been overlooked in practice, and the demand for air denied-this can easily be accounted for as regards close furnaces, from these circumstances: 1. That until it has been converted into flame, it is necessarily invisible; and, 2. That the place where it is so converted, is beyond the reach of observation-being beyond the bridge, to which part there is no usual access or means of seeing what is going on. In smelting furnaces, or in all operations where this gas arises in large quantities and meets the air at its exit from the top, it is strange that it should have been so long neglected, and that coke, which it is asserted burns without flame, should yet be attended with so large a body of it, without exciting attention to its heating powers, and the causes and circumstances under which the body of unquestionable flame is generated from a fuel which is said to burn without it. I propose continuing this subject in my next communication. I am, yours, &c.

C. W. WILLIAMS. Liverpool, January 4, 1842.

PATENT SOLAR LAMP.

Sir,-Our attention having been drawn to a letter in your publication of the 18th instant, headed "The Cap or Deflector Lamp, commonly called the Solar Lamp," and signed "A Constant Reader," in which letter our names are made use of, we shall be obliged by your inserting this communication in your next number.

It is generally known, that we are the proprietors of the patent right of the Solar Lamp, and "A Constant Reader" is evidently aware of this fact; the manifest object of his letter being to lead the public to suppose that the solar lamp

is one of Upton and Robert's contri

vances.

All that we think it necessary to state is, that we have some time since commenced an action, which is now pending against the same Mr. Upton, whose name is here mentioned in connection with Roberts (who is since dead,) for infringing our patent rights in the solar lamp, by selling a contrivance called "Young's Patent Oxydator;" and on the trial of that action, he will have a much better opportunity of showing whether the solar lamp is one of Upton and Roberts's contrivances, than can be afforded in any other way.

It is not our intention to be drawn by Mr. Upton, or his friend, "A Constant Reader" into a correspondence on the merits of the question between him and us, but we think it desirable, that the public, to whom "A Constant Reader" has addressed his observations, should be aware of the real state of the matter, and that we are at this moment taking against Mr. Upton the same course which we have already pursued against other parties who have infringed our rights, by seeking damages against him by legal proceedings.

Trusting to your sense of justice for the insertion of this letter, we are, Sir, Your obedient servants,

TIMOTHY SMITH AND SONS. Birmingham, December 29, 1841.

PLOWMAN AND QUARTERMAN'S MANUAL POWER FOR THRESHING MACHINES. (Registered Pursuant to Act of Parliament.) In our last volume (page 504) we published a description of a new Horse power" for threshing machines, designed by Messrs. Plenty, of Newbury. The accompanying engraving represents a new "manual power" adapted to similar machines recently introduced by Messrs. Plowman and Quarterman of Oxford. It consists of two horizontal bearers mounted upon suitable supports aa; upon these bearers a sliding frame is placed, which carries the bearings of the several axles. The centre of the frame is occupied by a large fly-wheel b, which carries a drum c; upon the prolonged axis of the fly-wheel a small spur wheel, or pinion e, is placed upon each end, which pinions revolve in the outer compartments

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Our party consisted of Mr. Smith, the inventor of the screw, in propria persona, a gentleman friend of his (who was disposed to go 66 a pleasuring," like myself, to enjoy the inviting breezes and invigorating fogs of an honest old-fashioned November, on broad, the open sea"), the Captain, the managing engineer, Mr. Ray the pilot, and your humble servant, all, with perhaps one exception, practical fellows, able to look a nor'-wester in the face without winking; and when the hauser was let go off Rownham, at exactly half-past ten A.M.,-for my own part, I felt ready for anything, from "pitch and toss to manslaughter."

You will remember that the morning of the 20th November came in fine and soft, and as I was going down to the Archimedes from the city, I was apprehensive that the run round to London would be a very dull and common-place affair, affording but small opportunity of testing the properties of the screw, more than could be done in a river. By the time, however, that we reached Kingroad it was piping up pretty fresh from the south-west, and when we rounded Posset Point, exactly one hour from the Basin, it was blowing hard right a-head, and as it looked black and murky to windward, I began to entertain hopes that I should have something to say to you ere we reached London.

The wind continued to increase as the day advanced, and when we feached the Holmes, at two o'clock, it was blowing a whole gale, and Mr. Ray, calling a council of war, re

presented, that as we should soon have the whole flood tide to contend with, during which it was not to be supposed that any vessel, against such a wind, could make much progress, and as it was necessary to husband the coal, of which we had only a limited quantity, he would advise our running into Pennarth, and seeing how it would be on the next ebb, as he was sure it would be "nothing but a real dirty night." This advice was adopted, and we let go our anchor in Pennarth Roads at half-past two o'clock, four hours from the time of leaving Bristol Basin, the last three of which it had been blowing very hard against us.

The justice of Mr. Ray's observations was soon established; for shortly afterwards the Victory and the Bristol bore up and came into the roads also, both vessels anxious to make good their time, and the latter with only a short distance (to Swansea) to run. The next morning (Sunday) it was blowing still very hard, with very unsteady wind, veering about from south-west to north-west, and the pilot still discountenanced our getting under weigh. The Victory, however, made another attempt, and succeeded, as I have since learned, in getting so far as Milford in the next twenty-four hours; but the Bristol remained, as well as ourselves, until the Monday morning, when, the wind having abated, though still westerly and fresh, we weighed anchor, resolved to take a final leave for that voyage of Pennarth, which we did exactly at twenty-five minutes past seven, in company with the Bristol.

At eight o'clock, hove the log, and found her going seven knots, wind west south-west, very fresh, engine making twenty-four revolutions per minute. At noon, strong winds and rainy weather. Half-past twelve, abreast of the Foreland, strong gale and heavy sea, and the Bristol we observed bearing up again for Cardiff (where, I have since understood, she landed her passengers); as, however, we were doing well, we kept on without the slightest deviation from our course till we reached Lundy Island, under which we anchored, at a quarter after seven the same evening, the wind continuing to blow a strong gale from west north-west to west. We accomplished the whole distance from Cardiff to Lundy at the average rate of five miles an hour, against such weather and a whole flood tide; Mr. Ray, the pilot, and several of the hands being perfectly astonished at the ease with which a true course was steered in weather in which, he asserted, many large and powerful steamers could not have been kept head to wind at all.

We lay at anchor, under Lundy, all that night and part of the next day, during which I got on shore to visit the natives. There

A TRIP IN THE

are, it seems, only thirty inhabitants on the island, apparently a healthy and a happy little colony; they told me, such a thing as a doctor on the island had never been heard of. Two, at least, of the lot are both pretty and agreeable, I can say that from my own observation, (this, of course, is not a part of "the log;") but as I suppose you want an account of the Archimedes, and not of Lundy Island, I proceed to inform you that, at about noon, on Tuesday, the 23rd of November, the wind hauled so far to the northward, as to admit of our setting the canvass, and we got under weigh at one o'clock P. M., a tremendous sea still tumbling into the chops of the Channel, from the westward, on account of the previous heavy gales from that point, notwithstanding which we found her going eight and a half knots by the patent log. At six the wind had become so strong, that we took in the main spencer. At eight, a heavy squall struck us, and blew away the jib; at half-past eight, a heavy gale and head sea, speed by log six and a quarter knots.

I was never more pleased,

myself, than when I came on deck in the midst of this hubbub, to see how beautifully this little vessel was performing her part; at this time she was making good six knots, with a terrible head sea on, and blowing too hard to carry any canvass. She was making excellent weather, and a boy might steer her; and, from first to last, the engine never varied above three or four strokes per minute, at no time exceeding twenty-five, nor being down so low as twenty, the whole voyage. This, to me, appeared the more singular, as I had observed such a striking difference in the action of the paddle-wheel engines, at different times, which labour dreadfully in a heavy head sea, and are liable to run away when scudding in similar weather, requiring to have the steam shut off, on account of the paddles being sometimes wholly out of the water. I have known the mighty Western reduced down to five strokes per minute, and even less, by the strength of the opposing wind and sea, though, when doing her best, she makes sixteen and seventeen strokes per minute. Talking of the Great Western, by the by, puts me in mind of the first gale of wind I experienced on board of her. At the time I speak of, the people were getting the yards down, and I was on the spar-deck, forward, lending a hand, when two or three seas, successively, slapped in over us, almost taking my breath away, and scarcely giving me time to recover it again; one of the hands, an old whaler, who stood near me, however, said to me, quite coolly, "Hold on, and never mind her, sir-she'll come up to blow presently;" thus identifying her, as a sailor delights to do, with a thing of life and habits.

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At half-past eleven at night we made the Longships; at midnight, very heavy squalls, with rain and hail. Rounded the Longships at about half-past three in the morning, and ran up the Channel all that day, at the rate of about nine knots. At half-past two in the morning of Thursday, we met a strong breeze from the eastward, notwithstanding which we were off Beachey Head by eight, when we sent down the gaffs and fore-yard, the wind continuing against us till two P. M., when it abated, and shortly afterwards fell calm. At half-past two, we hove-to off Sandgate for a couple of hours; and at seven, anchored in the Downs, after a run of thirty-seven hours' steaming from the Longships. Here the weather was quite calm, but very thick, and we remained at anchor until the following morning. Friday morning, at six, got under weigh, and, though constantly delayed by a dense fog, we were at Gravesend by four in the afternoon, and safely moored at Blackwall by half-past six on the same evening, (Friday, Nov. 26,) in six and a quarter days from Bristol, only three days nine hours of which we had been absolutely under weigh, accomplishing a distance of over six hundred miles, about half of which was against strong head winds and a heavy sea.

On

I don't imagine that the above needs any commentary, Mr. Editor. All I know is, that we passed every sailing vessel and steamer we fell in with between Bristol and London, and accomplished the voyage without unpleasantness of any sort, saving the weather alone. The vessel performed her work with uniform regularity, and every one on board was delighted with her; and if you have a doubt on any point, I refer you to Mr. Ray, the pilot, from whom Mr. Smith took a certificate of her behaviour during the severe gales in the Bristol Channel.

At

It should be borne in mind that the Archimedes is a vessel drawing eleven feet of water, and that she has little more than onehorse power to every four tons register; and I do not believe there is in the kingdom a paddle-wheel steamer, of the same proportion of power to tonnage, and the same draft of water, that would have a chance with her against a strong wind and heavy sea. any rate, I am sure there is not one that I would be so well pleased to be on board of in such weather; nor need you fear saying too much in favour of an invention, which is only kept from general adoption, either because it is unknown, or because people do not desire to know it. It is to me a complete puzzle; nor can I account for the in. difference with which the steam-navigation world appears hitherto to have regarded it, --so superior as it is, in every respect, as

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