CHAPTER VIII. 



THE " CONSUMPTION OF SMOKE.*' 



A GREAT deal has been spoken and written of this subject, but 

 practically nothing has been done. At one time I shared the 

 general belief in its possibility, and accordingly examined a 

 multitude of devices for smoke-consuming, and tried several of 

 the most promising, chiefly in furnaces for metallurgical work, 

 for steam boilers and stills. None of them proved satisfactory, 

 and I was driven to the conclusion that smoke-consumption is a 

 delusion, and further, that economical consumption of smoke is 

 practically impossible. When smoke is once formed, the cost 

 of burning it far exceeds the value of the heat that is produced 

 by the combustion of its very flimsy flocculi of carbon. It is 

 a fiend that once raised cannot be exorcised, a Frankenstein 

 that haunts its maker, and will not be appeased. 



To describe in detail the many ingenious devices that have 

 been proposed and expensively patented and advertised for this 

 object would carry me far beyond the intended limits of this pa- 

 per. I must not even attempt this for a selected few, as even 

 among them th?re is none that can be pronounced satisfactory. 



The common idea is that if the smoke be carried back to the 

 fire that produced it, and made to pass through it again, a 

 recombustion or consumption of the smoke will take place. 

 This is a mistake, as a little reflection will show. First, let us 

 ask why did this particular fire produce such smoke ? Every- 

 body nowadays can answer this question, as we all know that 

 smoke is a result of imperfect combustion, and, knowing this, 

 it can easily be understood that to return the carbonic acid and 

 excess of carbon to the already suffocated fire can only add 

 smother to smotheration, and make the smoky fire more smoky 

 still. 



There is, however, one case in which a fire appears to thus 

 consume its own smoke, but the appearance is delusive. I 

 refer to fires lighted from above. These, if properly managed, 

 are practically smokeless, and it is commonly supposed that 

 smoke passes from the raw coal below through the. burning 

 coal above, and is thereby consumed. The fact is, however, 

 that no such smoke is formed. That which under these condi- 

 tions comes from the coal beneath, when gradually heated by 



