80 



FIRST YEAR SCIENCE 



face of the hot ball and the ball had then been cooled until its tem- 

 perature approached the temperature of the cold surrounding spherical 

 surface, it would have shrunk away from this spherical surface. This 

 would leave an unfilled space between the two into which the spherical 

 shell must have shrunk if not strong enough to support itself. This 

 shrinking would cause wrinkling in some parts of its surface. 



Experiment 41. When at home measure the greatest and least 

 circumference of a large smooth apple by winding a string around it 

 and then unwinding and measuring the length of the string. Bake the 

 apple. Measure its circumferences again. Are they greater or less 

 than before ? Is the skin of the apple as smooth as it was before ? 



Not only do the land areas differ greatly in the kind of 

 rocks of which they are composed, but also in the way in 

 which these rocks are placed. Some of the rocks lie nearly 



STRATIFIED ROCK. 

 These layers have remained horizontal as originally formed. 



in the condition in which they were originally formed 

 while others have been folded and warped and twisted. 



