122 EFFECTS OF HEAT. 



CHAPTER X. 



EXPANSION FROM HEAT. 



(Continued.) 



Q. Does heat expand every thing ELSE BESIDES 

 air and water ? 



A. Yes - 9 every thing (that man is 

 acquainted with) is expanded by heat. 



Q, Why does a COOPER make his HOOPS RED- 

 HOT, when he puts them on a tub ? 



A. 1st As iron expands by heat, 

 the hoops will be larger when they are 

 red-hot; and will, therefore, fit more 

 easily on the tub : and 



2ndly As iron contracts by cold, the 

 hoops will shrink as they cool down, and 

 girt the tub with a tighter grasp. 



Q. Why does a WHEELWRIGHT make his 

 hoops RED HOT, which he fixes on the NAVE of a 



WHEEL ? 



A. 1st That they may fit on more 

 easily: and 



2ndly That they may girt the nave 

 more tightly. 



