60 



HEAT 



Is the flame as hot as the flame of the alcohol? Why? 

 Which combustion is best? 



c. Hold a piece of chinaware 

 in the flame of the turpentine 

 lamp. What collects upon it? 

 What is its color? 



d. Hold the piece of china- 

 ware, with its coating, in the 

 flame of the alcohol lamp for sev- 

 eral minutes. What does this 

 prove about the wastefulness of 

 smoky combustion? 



e. Light the Bunsen burner 

 and note the difference in the 

 flame when the air vents are 

 closed and when they are open. 

 When is combustion more nearly 

 perfect? 



Ai? 



23. Combustibles and Fuels. 



Anything which burns is a combustible. Fuels arc 

 only those combustibles which we ordinarily burn to 

 produce heat. You are familiar with the common fuels 

 which are coal, coke, wood, charcoal, oil and gas. What 

 do you notice when you burn them? Do they all burn 

 with a flame? 



In any combustion it is necessary to have air. In 

 our stoves the amount of air is regulated by dampers. Do 

 you open or close the dampers when you want a hot fire? 

 If there is not enough air the fire will smoke, and finally 

 go out. What causes incomplete combustion? 



