TABLE OF CONTENTS xix 



CHAPTER XIX 



PAGES 



IRRIGATION IN HUMID CLIMATES 406-418 



Dry seasons, 407 Results of irrigation in humid 

 regions, 409 Methods of applying water, 412 The duty 

 of water, 413 Sources of water, 413 Water-conserva- 

 tion methods, 414 Value of sewage water, 414 The 

 use of sewage, 415 Factory and mill waste, 417. 



CHAPTER XX 



IRRIGATION TOOLS AND DEVICES 419-444 



Clearing and breaking the land, 419 Laying-out the 

 farm, 420 Leveling the land, 423 Making farm 

 ditches, 426 Gates and checks, 434 Ridging and fur- 

 rowing, 439 Mulching the soil, 440 Measuring the flow 

 of water, 441. 



CHAPTER XXI 



THE HISTORY OF IRRIGATION 445-471 



The antiquity of irrigation, 445 The Christian era to 

 1800, 449 Irrigation in recent times, 451 The found- 

 ing of modern irrigation in America, 454 The growth of 

 American irrigation, 457 The Union Colony of Colorado, 

 460 The United States Reclamation Service, 461 

 The United States Department of Agriculture, 464 

 The experiment stations, 466 The Irrigation Con- 

 gress, 470. 



CHAPTER XXII 



PERMANENT AGRICULTURE UNDER IRRIGATION . . . 472-476 

 The big irrigation problem, 472 The spirit of irrigation, 

 473 No essential difference between irrigation- and 

 humid-farming, 473 History assures permanence of 

 irrigation, 474 The question of plant-food, 474 Some 

 advantages of irrigation, 476 Finally, 476. 



