WHAT IS IT THAT BURNS IN FUELS? 



179 



QUANTITIES OF HEAT OBTAINED FROM VARIOUS FUELS FOR 

 ONE CENT 



give one hundred per cent 

 so in practice, you could 

 boiling point as is indi- 

 cated by the table above. 



If you wish to heat 

 only a kettle full of water 

 the coal range gives 

 much less efficient serv- 

 ice than the gas range, 

 even though gas may 

 cost more for a given 

 number of heat units. 

 Do you see why this is? 



What is it that burns 

 in fuels ? If you hold 

 a clean glass plate in the 

 flame of a candle, you 

 will notice a thick, black 

 -deposit gather on that 

 part of the plate exposed 

 to the flame. This ma- 



efficiency in the burning of fuel, 

 not heat as much water to the 



Carbon from a candle. 



