The Use and Care of Water 87 



It now aids in carrying on trade between different regions. 

 If large and deep enough, it permits boats from all parts of 

 the world to reach the very heart of our country. 



Canals might be called artificial rivers. They serve an 

 important purpose in nearly level countries where Nature 

 has placed no navigable river. Although canal boats 

 usually move slowly, yet they can carry goods cheaper than 

 railroads can. The Erie Canal, in connection with the 

 Great Lakes and the Hudson River, makes it possible for 

 us to go all the way by water from the heart of the continent 

 to New York City. The Erie Canal has helped make New 

 York City the greatest city in our country. The canal 

 across the Isthmus of Panama saves ships a journey of many 

 thousand miles around South America. 



Rivers serve us in yet another way by affording water 

 for irrigation. A great river like the Colorado flows through 

 regions of many different climates. Some rivers become 

 . so small in the summer that it is necessary to build great 

 reservoir's at their headwaters in order to insure a supply 

 when the crops need it. But in the case of the Colorado 

 this is not necessary. The headwaters of this river are 

 among lofty mountains, where the melting snows and 

 summer showers make the waters of the river higher in 

 the early summer than at any other season of the year. 

 Thus its great delta, the Colorado Desert, has become the 

 home of many thousands of people. 



Another use which we make of rivers is by putting the 

 water to turning mill wheels. If you will turn to your 

 geographies, you will find that nearly all the great manu- 

 facturing cities of our country have grown up around rapids 

 or waterfalls, where some river tumbles over a ledge of rocks. 



