320 



Common Science 



is too large, the flame 

 " blows " ; there is too 

 much cold air coming in 

 with the gas, and your 

 flame is not as hot as it 

 would be if it did not 

 " blow." Also, the stove 

 is liable to "back-fire" 

 (catch fire at the air open- 

 ing) when the air opening 

 is too wide. 



Application 69. An oil 

 lamp tipped over and the 

 burning oil spread over the 

 floor. Near by were a pail 



FIG. 168. The Bunsen burner smokes when r watpr nqn n r a cV, P c 

 the air holes are closed. ot Water > a P an ot ashes > 



a rug, and a seltzer siphon. 



Which of these might have been used to advantage in 

 putting out the fire? 



Application 70. My finger was burned. I wanted the 

 flesh around it to heal and new skin cells to live and grow 

 rapidly around the burn. 



" Put a rubber finger cot on the finger and keep all air 

 out," one friend advised me. " Air causes decay and will 

 therefore be bad for the burn." 



" He's wrong ; you should bandage it with clean cloth ; 

 you want air to reach the finger, I've heard," said another 

 friend. 



" Oh, no, you don't ; air makes things burn, and the burn 

 will therefore get worse," still another one said. 



What should I have done ? 



Application 71. Two students were discussing how coal 

 was formed. 



" The trees must have fallen into water and been com- 

 pletely covered by it, or they would have decayed," said 

 one. 



