Fire and Heat 127 



merely into carbon monoxid. This represents a loss of about 

 10,000 B.T.U. per pound of carbon or a waste of nearly two 

 thirds of the fuel. If the soot together with carbon monoxid 

 escapes, the combustion is much less perfect, and the loss of 

 fuel and therefore of money is correspondingly greater. 



Smoke and soot are of practical interest to every one. In com- 

 plete combustion smoke is not driven out and lost, and soot is 

 not accumulated in the range and chimney or distributed 

 broadcast. In incomplete combustion, fuel is wasted. Stoves 

 and heating appliances in general do not secure complete com- 

 bustion. With proper control, however, fuel may be burned 

 more completely and the heat more fully utilized. This is 

 why men in charge of industries where great quantities of fuel 

 are consumed, employ every possible means to secure complete 

 combustion, or allow no smoke to escape. They are con- 

 cerned in stopping waste and saving money. The smoke nui- 

 sance, as this is experienced in many places, is thus an economic 

 problem as well as one of health and beauty. 



Conditions of incomplete and complete combustion. We may 

 summarize briefly the important conditions favoring incomplete 

 combustion and the consequent loss of fuel. These are : 



1. An insufficient supply of air or oxygen. 



2. Combustion somehow checked and the temperature re- 

 duced below the point at which carbon particles are completely 

 oxidized or burned to carbon dioxid. 



3. An accumulation of ashes in the grate or bed of coals, 

 which prevents air from coming into contact with the heated 

 carbon and liberated gases. 



4. Fuel supplied in such a way as to prevent the burning 

 of the gases liberated by the heat. 



The conditions of complete combustion are these : 



1. Proper regulation of the drafts. 



2. Keeping coal nearly free from ashes and the grate clean to 

 insure entrance of abundant air. 



3. Proper distribution of fresh fuel over the hot coals. 



