EXERCISE 10 



Problem. Does fire use up some part of the air or does it produce new 

 gases ? 



What to use. A tall cylinder to inclose air ; a basin of water to a'ct as 

 a seal for the air ; cork float holding candle on water. 



What to do. Light candle, float on water, invert jar and carefully place 

 over candle and float. 



Record. Note all the changes that take place. 



Questions. 1. Is the same proportion of the air used up in every fire? 



2. Is the remaining air different from fresh air ? 



3. From what happened, can you tell just what part the air took in the burning? 



