CHAPTER XV 

 FUELS AND CARBON COMPOUNDS 



Fuels. Fuels are materials used for producing heat. 

 They must be capable of uniting with oxygen under 

 easily pbtainable conditions, with sufficient rapidity to 

 insure the evolution of considerable heat energy. These 

 conditions are largely filled by carbon and its compounds, 

 occurring as gases, liquids, and solids. 



f wood 

 Impure fuels solids '' . .. > . . .1 p ea t 



[ soft coal 

 (" hydrogen 



gases . ; . ...:; -hydrocarbons 

 carbon 



Nearly pure fuels 



liquids 



alcohols 

 hydrocarbons 



I* anthracite (hard coal) 

 solids . . . . . . . i C oke 



[ charcoal 



Wood was probably the first fuel used by man. 

 Peat came into quite general use in Europe during the 

 middle ages and is still used to some extent (Figure 225). 

 Soft coal was first used during the fifteenth century, 

 while gas and hard coal were not used until the first part 

 of the nineteenth century. Hydrocarbons in the form of 

 gasoline and kerosene and certain artificial gases were not 

 used for fuel until the middle of the nineteenth century, 



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