1842.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



19S 



made in a coffee-pot distinguished by smsU boles of the patent diffu- 

 sion description. 



We are perfectly aware, in common with every one who has not 

 been educated inCaffraria or Timbuctoo, that gas may be burned with 

 smoke or without smoke; and we are willing to admit — if the ad- 

 mission will gratify this gentleman — that the Argand burners of 

 Regent-street are much better calculated to promote perfect com- 

 bustion than the barbarous expedients of the butchers' stalls. But 

 the question is not which of these appliances is calculated to accom- 

 plish combustion most completely, but whether the aeriform matter 

 proceeding from the orifices of the Argand burner and from the pipe 

 of the butcher's stall is the same or different : whether if the gas, as 

 it emerges from the orifices of the respective tubes, were to be 

 separately collected and analysed, it would be in the one case found 

 to be genuine and veritable gas, and in the other smoke merely. That 

 such would be found to be the case we do not believe. We do not 

 believe Ibat the circumstance of aeriform matter, or any other matter, 

 being made to flow through a large hole, or tlirough a small hole, can 

 change its specific and proper character — that the size of the orifice 

 through which it escapes determines whether a substance is smoke or 

 gas, or whether a furnace is a smoke-burning or a smoke-preventing 

 one. To talk about Argand burners, as if any species of burner could 

 convert a gasometer of smoke into a gasometer .of gas, is idle and 

 ridiculous; and to compare a furnace with an Argand burner because 

 it is furnished with small holes, is just about as rational as to compare 

 it with a patent coffee-pot, or a kitchen strainer — inventions which 

 participate in the same distinctions. 



But an excess of air, it is said, is unfavourable to combustion. We 

 know it well. Too much air, if admitted into the flue or furnace of a 

 boiler, will augment the generation of smoke as effectually as too 

 little ; but this is caused not by an excess of oxygen, but by a defect of 

 temperature, and has no more relation to the question before us than the 

 allegation that though a candle to burn properly must be surrounded by 

 air,yet ablast of air will extinguish it. In practice so much cold air may 

 be admitted into a furnace that its temperature will fall beneath the 

 point necessary for the inflammation of the combustible gases evolved, 

 and their combustion may thus be prevented, not by an excess of 

 oxygen, but by a destitution of heat. But the quantity of cold air to 

 which this effect is due is m\ich greater in amount than the excess 

 requisite for the combustion of the smoke; and the inflammation of 

 the gases may be maintained either by diminishing the quantity of air 

 admitted, or by elevating its temperature. The antiphlogistic pro- 

 perty of the influent air, then, is not one of its specific and necessary 

 characteristics, but one accidental to its temperature merely, and does 

 not in the least invalidate the necessity of admitting air to smoke in 

 excess, to achieve the combustion of its inflammable portion. 



To correct the impracticability of apportioning the admission of 

 air in an ordinary smoke-burning furnace to the perpetual fluctuations 

 in the quantity of smoke evolved, Mr. Williams says "I separate the 

 air into two supplies, thus rendering them more manageable, and what 

 is more important, less liable to interfere with and mar each other's 

 obiects ; a system,too, which has also this practical value — the causing 

 them to be to a great extent mutual correctors of each other's defects." 

 This intimation has certainly the merit of being hieroglyphical and 

 cabalistic enough to defy criticism, and precludes any very specific 

 rejoinder. We must, therefore, be content to' remark, that as it is an 

 intimate admixture between the atmospheric air and the gaseous 

 matter, whatever be its nature, which proceeds from the fire, that this 

 gentleman professes to accomplish, his arrangements, supposing them 

 to perfectly attain that object, and that smoke-burning is assumed to 

 be desirable, will be valuable or not, just in proportion as the same 

 end is attainable or unattainable, by other or simpler means. Now, 

 the admission of a snfliciont quantity of air to the smoke, or the 

 thorough diffusion of that air, has never been fovmd to be a point of 

 difficulty. Indeed there is no furnace whatever, in which, by a proper 

 regulation of the draught and of the depth of coal upon the grate, any 

 quantity of oxygen may not be enabled to ascend to the smoke through 

 the fire; In scarcely any furnace does all the oxygen which enters the 

 ash pit enter into combination with the fuel ; a part almost always 

 escapes in its uncombined state through the burning embers, and by 

 the mere regulation of the draught and of the thickness of the incan- 

 descent stratum, this quantity of oxygen may be made as great or as 

 small as may be desired. As this oxygen ascends not in one part of 

 the grate, but through every part of it, it must be necessarily equably 

 diffused among the incombustible gases and inflammable substances 

 present, and must, moreover, be of as high a temperature as the fire 

 in its passage is able to impart. If this adequate supply of oxygen 

 equably diftused among the smoke be attainable in any ordinary fur- 

 nace — and that it is must be perfectly self-evident — wherein lies the 

 necessity or benefit of this gentleman's difl'usion apparatus? Not only 



can the requisite quantity of oxygen be let in to the smoke througb 

 the fire, and be equally well diffused without any apparatus at all, but 

 the oxygen so let in will, moreover, be of a high temperature — a 

 condition highly favonrable to combustion. As to the air being 

 admitted in two supplies or in a hundred supplies, that point is one of 

 perfect unimportance. The only point of moment is whether the 

 requisite supply of oxygen is present, and that oxygen is equably 

 ditt'used ; and if this condition be fulfilled, it matters liot one iota how 

 the oxygen got there, or by what means its diffusion has been accom- 

 plished — whether by the instrumentality of diffusion orifices, or whether 

 it has made its way through the interstices of incandescent fuel upon 

 the bars of the grate. 



We spoke so fully in our former remarks of the inherent and 

 necessary defects of smoke-burning arrangements generallv, that it 

 would be superfluous now to say anything more upon the subject. 

 This gentleman's invitation to investigate the merits of different 

 smoke-burning schemes, if accepted, would lead us into an invidious 

 and unprofitable discussion. Of two plans positively injurious, there 

 is little advantage to be conferred by showing that one is rather worse 

 than the other. It is sufficient to show that both are worse than the 

 methods most known and practised, and are, therefore, nndeservmg of 

 further attention. Furnaces of the ordinaiy description will produce 

 very little smoke, if the coals be spread thinly upon the bars, and the 

 draught be pretty good ; for in that case a sufficiency of oxygen will 

 find its way through the fire to accomplish the combustion of the in- 

 flammable parts of the smoke. It is usual and beneficial to have a. 

 dead plate at the mouth of the furnace, and a few holes in the furnace 

 doors, the purposes of which are obvious. 



But it is time that we should turn to A. S., to ascertain what he is 

 able to advance in favour of Mr. Williams' smoke-preventing preten- 

 sions. His whole argument rests upon the imputed fallacy of the 

 definition of smoke given in oun former article, and it is, therefore, 

 sufficient for us to show, in reply, that the definition we there gave is 

 the natural, universal, and correct one. We defined smoke to be "the 

 product of imperfect combustion" — a definition A. S. altogether 

 repudiates. "Smoke," says our correspondent, "is here defined to 

 be the product of imperfect combustion ; but what are we to under- 

 stand by the term imperfect combustion ? there is no such thing ia 

 nature. Who ever heard of imperfectly-formed carbonic acid or 

 of steam without a saturating equivalent of oxygen ?" 



In saying that combustion, which is an act of chemical conibinatioD^ 

 is imperfect, we can only be supposed to mean that the process of 

 combination, owing to the co-existence of some such agency, has not 

 been perfected : — in other words, that although some of the atoms of 

 the one body have entered into combination with some of the atoms 

 of the other, yet that the remaining atoms have not entered into com- 

 binations, owing to their subjection to some such influences as those 

 we have indicated. The use of the term imperfect combustion, then, 

 does not involve the supposition that carbonic acid is imperfectly 

 formed — although it is not certain that.there may not be a species of 

 combustion which generates carbonic oxide — but that the act of form- 

 ing carbonic acid in quantity proper to ingredients present, has not 

 been completed or perfected. Any other supposition would not only 

 be gratuitous, but opposed to the whole tenor of chemical science, 

 and it is difficult to suppose our correspondent to have believed that 

 an opposite tenet was held by us. 



But again, the term "imperfect combustion" is that employed by 

 all chemical authorities, and what perhaps is more to the present pur- 

 pose, it is that employed by Mr. Williams. We feel that it would 

 weigh but little with our correspondent to adduce the authority of 

 Sir H. Davy, Dr. Dalton, Berzelius, and Dr. Thomson, showing that 

 smoke is the product of imperfect combustion caused either by the 

 want of oxygen or the want of heat. But our correspondent 

 cannot surely refuse to bow to the authority of Mr. Williams. 

 Let him turn, then, to the 24th page of the appendix to Mr. Williams* 

 treatise, and he will find an extract from the specification of his patent 

 which runs thus : — " Smoke is the result of the impekkect coMBUSTioit 

 of the volatile products." After this we feel it would be superfluous 

 to say another word on the subject. 



Our correspondent says that Mr. Williams' furnace has been very 

 successful in practice, which is probably true enough, if we look upon 

 success as the capability of being endured, or as a measure of bene- 

 ficial effect, such as other smoke-burning schemes have succeeded iu 

 attaining. There is, perhaps, no smoke-lmrning scheme whatever of 

 which the same thing may not be predicated as our correspondent 

 alleges of this ; for as we formerly mentioned, smoke-burning schemes 

 may, with great care, be rendered instrumental in saving fuel, but in 

 the aggregate of continued and ordinary working, there is always 

 either a diminished efficiency or an increased consumption. In the 

 evidence given before the committee of the House of Commons on 



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