Dr Fyfe on the Prevention of Smoker 4*<?. 57 



appearance ; the smoke disappears, the flame becomes more 

 brilliant, and the heat seems to be more intense ; at the same 

 time, if smoke was escaping at the top of the chimney it very 

 soon disappears ; the time depending on the height of the 

 stalk and on the draft ; and as long as the steam continues to 

 be projected from the distributor, little or no smoke is visible. 

 I conceive it is unnecessary to say more on this valuable part 

 of the process ; it has been witnessed by many, who can bear 

 testimony to the efficacy of steam when used in this way as a 

 complete preventive of smoke fi'om furnaces however large. 



I now proceed to the more important part of the process, 

 I mean the effect on the evaporative power of the coal con- 

 sumed. The prevention of smoke, and the consequent absence 

 of soot on the sides of the boiler, would naturally lead to the 

 supposition that a gi-eater amount of evaporation would be 

 produced, not only because that part of the fuel which other- 

 wise escapes as smoke is consumed, but also owing to the ab- 

 sence of soot on the boiler, the transmission of heat would be 

 more rapid, and consequently being more quickly taken up, 

 less of it would be lost by passing up the chimney. These 

 causes must operate to a certain extent, in every instance 

 where smoke is prevented ; but we shall tind that the increase 

 in evaporation is far beyond what could be accomplished by 

 these alone, as the result of the trials which I am now to state 

 will shew. I consider it unnecessary to state minutely the 

 details of the numerous trials I have conducted with this pro- 

 cess. I will first give the details of one which I select, because 

 during its performance the most rigorous attention was paid 

 to every thing that could affect the working, and it will there- 

 fore shew how the trials were in general conducted. 



