54 ELEMENTARY SCIENCE 



This chapter began to tell of man's supply of water, and 

 then, to explain about wells and springs, it went clear back 

 to the start of things. It told a little of the history of the 

 earth. This may seem like getting away from the story. 

 But you will find it is always so in studying the story of 

 nature. In order really to understand the little things, 

 you have to go back to the big and ancient things. It is 

 a continuous story, but it continues out and back in every 

 direction rather than in a straight line. To understand 

 what we see to-day, we must understand these great forces 

 which have shaped the earth since it began, and which still 

 govern it and its tiny creatures. 



QUESTIONS 



1. Why does a well have water in it? 



2. How was coal made? 



3. What is meant by "sedimentary" rock? 



4. Describe an ordinary well, a spring, an artesian well, and a 



gushing oil-well. 



