388 Introduction to the Study of Science 



covery of the cause and means of prevention of yellow fever and 

 malaria. 



Other notable canals are (1) the Suez Canal, (2) the Marseilles- 

 Rhone Canal, (3) the Manchester Ship Canal, (4) the Erie Canal, 

 and (5) the Soo Canal. 



Locks use the energy of falling water to lift the ships. 



Our Great Lakes are a highway for a vast tonnage of ore, coal, and 

 grain. 



REVIEW QUESTIONS 



I. Why is the improvement of harbors important? 2. What 

 has been done to improve the harbor of New York? Of San Pedro? 

 3. What facilities for loading and unloading are found in the harbors 

 of the Great Lakes? 4. Give an account of the amount of material 

 carried by the Mississippi River per year. 5. (a) What has been 

 done to prevent floods? (6) What to prevent the building up of the 

 river bed ? 6. What has caused a reduction of traffic on inland water- 

 ways and hindered their development? 



7. Give a brief account of the construction of the Panama Canal. 

 8. (a) What are the chief advantages of the canal to the United States ? 

 (6) What are its advantages to the world? 9. What European in- 

 land cities are made seaports by ship canals? 10. (a) Explain how 

 the locks are operated to pass a vessel from higher to lower level. 

 (6) From lower to higher level. 



II. Give an account of the importance of the Great Lakes as a 

 waterway. 12. What materials make up the bulk of the freight on 

 the lakes? Why? 



SUGGESTIVE QUESTIONS 



1. What was the effect of the construction of the Erie Canal upon 

 the settlement of the Middle West? 2. How has inland transporta- 

 tion by water determined the development and location of cities? 

 3. What canal competes with the Panama Canal in European and 

 Asiatic commerce ? 4. Which is the shortest route between Liverpool 

 and Yokohama? Liverpool and Valparaiso? 5. In what direction 

 does a vessel pass from the Gulf of Mexico to the Pacific Ocean through 

 the Panama Canal? 6. The water of Gatun Lake has become salty 

 since the canal has been in use. As it is 85 feet above sea level, how 

 do you account for it? 7. If the rainfall of the Isthmus should cease, 

 could the canal be operated? 8. Will the canal be useful to sailing 

 vessels going East ? 9. How is coal transported to (a) Cincinnati ; 

 (6) St. Louis ; (c) New Orleans ? 10. Why did the United States Steel 

 Company locate its plant at Gary, Indiana ? 



