336 Introduction to the Study of Science 



power? 6. Compare advantages of steam and electricity as motive 

 power of transportation. 



7. Describe a simple electric generator and name the parts. 

 8. What is the difference in construction between the D. C. and A. C. 

 generator? What parts are alike? 9. What is the purpose of the 

 commutator? Of the brushes? 10. Mention an important differ- 

 ence between gasoline engines and steam engines. A fundamental 

 likeness. 11. Upon what has the development of the automobile 

 depended ? 12. What use is made of the electric current by the gaso- 

 line engine? 



13. Describe how a four-cycle gas engine works ; a two-cycle. 

 14. Describe the dry cell. Which is the positive binding post ? What 

 is a battery? 15. Describe a lead storage cell. Does it store, chemical 

 energy or electricity? 



