106 ELEMENTABY AGBlCtJLTtJBE 



the year round, while others must be filled in the 

 rainy season. The United States Government is 



Fig. 56. A private irrigation plant. 



spending millions of dollars in the dry sections to 

 save for crops some of the water that is going to 

 waste. 



Making Machinery Better. A slight improvement 

 on the crooked stick was a rude plow made from 

 several sticks bound with thongs of skin. This was 

 used after the ox had been taught to bear the yoke. 

 Farming with such tools was hard and toilsome 

 labor with little reward. A brush dragged over the 

 plowed ground was probably the first harrow. 



Copper Tools. It was a great step forward when 

 some one learned to smelt copper. Though copper 



