42 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[Feb. 



which in ordinary furnaces coal must of necessity produce, and some 

 of these perhaps would have been completely successful, except for the 

 radical defect they had all to contend against, originating in the 

 chemical composition of smoke, which, once formed, can never be 

 completely consumed without the admission of so much air as will by 

 its cooling agency more than compensate for whatever heat the com- 

 bustion of the smoke occasions. Smoke may therefore be regarded 

 as a mixture of combustible and incombustible gases, in such propor- 

 tions as to prevent the combustion of the mixture with practical 

 economy ; the incombustible portion being chiefly composed of nitro- 

 gen and carbonic acid, which prevent the combustion of smoke, on the 

 same principle that water shaken up with it prevents the inflamma- 

 tion of oil. Hence the attempt should be, not to burn that whicli is in 

 its nature incombustible, but to ignite the gases extricated from the 

 coal immediately on their evolution, and without affording tliem the 

 opportunity cf becoming commingled with the uninflammable products 

 of combustion."* In other words, it is gas, not smoke, that should be 

 attempted to be burned ; and this it is that this gentleman professes 

 to do. The distinct enunciation of the smoke-preventive principle, 

 as being susceptible of practical application, and as pregnant with the 

 most important eftects, is one thing; the contrivance of the means 

 proper for the successful application of this principle, is another 

 thing: and we are quite willing to render to this gentleman whatever 

 honour appears to be due to him, for a priority in either of these 

 achievements. 



All smoke-burning projects operate upon tlie principle of admitting an 

 excess of air into the furnace or flue, and this principle is attended 

 with two insuperable and fatal objections. First, the refrigerating 

 effect of the great excess of air it is necessary to admit to a mixture 

 of combustible and incombustible gases, to accomplish the indispen- 

 sable condition of combustion — proximity of the atoms to be combined; 

 and second, the impracticability of apportioning the admission of air 

 to the ever-changing quantity of smoke evolved from an ordinary fur- 

 nace. Smoke-burning furnaces, therefore, although they have in some 

 well-authenticated instances succeeded in accomplishing a saving of 

 from 12 to 14 per cent., with the attention accorded to novel and 

 experimental projects, have in the aggregate of ordinary working 

 invariably been productive of a diminished efficiency, or an increased 

 consumption. Though again and again revived, the project of smoke- 

 buruing lias as often expired of perfect inanition. Yet each successive 

 projector has had some modification to propose, which it was alleged 

 would render success inevitable. Thus, one having admitted the air 

 through a round or square hole, and having failed in realizing a satis- 

 factory result, another has attributed the failure to tlie indiscretion of 

 not having admitted the air through a slit, and has based his proceed- 

 ings upon that discovery. One has worked with the assistance of an 

 air valve, and another without that assistance. One has transmitted 

 the air to the smoke through orifices in the sides of the furnace im- 

 mediately above the bars of the grate; another through a hollow 

 bridge, and a third through pipes which carry the air into the flues ; 

 the efflux of the air being in some cases through one hole, in other 

 cases through many holes. But it is plain, that all such modificatioas 

 as these leave the real difficulties of the case untouched ; inasmuch as 

 there remains the same necessity to admit a great excess of air, to 

 accomplish anything like complete combustion, and the same imprac- 

 ticability of adjusting the quantity of influent air to the variable con- 

 ditions of the fire. These difficulties are not inseparable from the 

 smoke-preventive system ; and we were therefore warranted in 

 expecting from Mr. Williams some contrivance from which they would 

 be altogether excluded, and which might be regarded as an incarnation 

 (so to speak) of the principles of smoke-prevention. But the partu- 

 rient mountain has again brought forth a mouse. This learned 

 pl'.ilosopher, after vapouring about atoms, gases, and prevention, 

 throughout the length and breadtli of an octavo volume, presents us 

 with — what ? a veritable antique smoke-burning furnace. A smoke 

 BUBNISG furnace? Yes, readers, 'tis even so. You may well be 



" Thoughs o.n S'.eam Locomotion. Ldinlon : W"er.^>, 18'IC). 



petrified at tliis most lame and impotent conclusion. Yet so it is. Our 

 philosopher, after raising us to the tip-toe of expectation, by pro- 

 mising to shew us, NOT how amoke vtaij be burned, but how coals may 

 be burned withoul smoke, ruthlessly demolishes the fairy fabric our 

 fancy had created, and congeals us into stone, by holding up a iledusa's 

 head, in the form of a smoke-burning furnace, of which the sole pecu- 

 liarity is, that the air enters by a greater number of holes than usual. 

 Whether of two smoke-burning projects the least exceptionable is 

 that which admits the air at one hole, or that which admits the air at 

 many holes, it would be irrelevant at present to inquire. Our own 

 predilections are in favour of the latter method ; though we are by no 

 means prepared to maintain, that the admission of the air through a 

 few judiciously disposed long and very narrow slits might not be 

 greatly preferable to both. At present, it is sufficient for us to shovT 

 that this gentleman's furnace operates not upon the smoke-preventive, 

 but upon the smoke-consumptive principle; tliat it is a mere smoke- 

 burning furnace, attended with the objections we have already men- 

 tioned as fatal to smoke-burning plans. 



To the proof then. At the back of the fire bridge of this gentle- 

 man's furnace the air is admitted through a number of minute orifices, 

 and mingles with the aeriform matter proceeding from the coal upon 

 the bars of the grate. There are no means provided of regulating the 

 quantity of air admitted through these minute orifices, other than pre- 

 existing smoke furnaces possessed. The only question therefore to 

 be decided is, whether the triform matter proceeding from the coals 

 on the bars of the grate is gas, or smoke. To determine this it is ne- 

 cessary first to ascertain whether combustion does, or does not take 

 place, in the furnace during the evolution or production of the said 

 aeriform matter. Our philosopher says that combustion does not take 

 place, inasmuch as he has doors to his ash-pit which he shuts immedi- 

 ately that the furnace has received a charge of fresh coals, and which 

 he keeps shut until the gas is all expelled. If this be done any aeri- 

 form matter presented for combustion at the anterior air orifices, will 

 certainly be noi smoke but gas. If on the other hand combustion take 

 place within the furnace during the carbonization of the coal, the 

 sriform matter presented for combustion at the air orifices, will be 

 not gas but smoke. The question therefore resolves itself into this 

 Does or does not combustion take place in the furnace during the car- 

 bonization of the coall Now if combustion do not take place in the 

 furnace during the carbonization of the coal, and as the volitilization 

 of the unfixed parts of the coal requires a large amount of heat for its 

 accomplishment, there must be some available source of heat other 

 than combustion from which the requisite quantity is supplied, our 

 philosopher says that the red hot embers of the fire are this source of 

 heat. But it is manifestly impossible for any body to give out half 

 its heat to another body and remain as hot or nearly as hot itself. 

 Besides the great quantity of heat which becomes latent when solids 

 or liquids are transformed into gases, is left without any provision. A 

 very simple computation would show — the weight, temperature and 

 specific heat of the incandescent embers, and the weight, temperature 

 and latent heat of the gases, (or vphat is equivalent — their weight, 

 temperature, volume and specific heat) being given — that no practica- 

 ble method of working this gentleman's furnace, would render the 

 embers on the grate an adequate distributor of the heat requisite to 

 expel the gases resident in the coals which constitute a charge of the 

 furnace. But it would be preposterous to resort to Algebra to esta- 

 blish a self-evident proposition. Every one knows that if green coals 

 be thrown ujwn a fire, and at the same time air be excluded, the coal 

 will not be carbonized, but the fire will go out: and even in a coke, 

 oven carbonization will remain unaccomplished, unless air is admitted. 

 If this effect be consequent upon the exclusion of air even where the 

 process of carbonization is aided by the heat of a mass of incandescent 

 brick work, how preposterous would it be to conclude that carboniza- 

 tion can take place in a hermetically sealed boiler furnace, where the 

 process is impedtd by the refrigeration of the water of the boiler ! If 

 then there is no combustion in this gentleman's furnace, and if at the 

 same time gas is evolved, there reuiains no conceivable source of the 

 heat absorbed during volatilization, except the act of volatilization it- 



