526 CEMENTS, LIMES, AND PLASTERS. 



"As compared with coal-gas, the proportions of CO and H in wood- 

 gas are reversed, and the percentage of CC>2 is doubled. With the 

 typical compositions (see page 525) the wood-gas shows less tendency 

 than the coal-gas to pre-ignition in the engines. This effect appears to 

 be due to the large proportion of CC>2, but the reason why this is so 

 is not apparent." 



Charcoal. 



The use of charcoal as a rotary kiln fuel has been seriously sug- 

 gested recently by at least one engineer for a plant located where no 

 other type of fuel was obtainable at reasonable rates. It is, however, 

 a matter of serious doubt whether this material could be brought to 

 ignite properly before it reached the stack. 



