330 



THE IRKIGATION AGE. 



THE PRIMER OF IRRIGATION. 



BV D. H. ANDERSON. 



DR. A. C. TRUE. 



DIRECTOR OFFICE EXPERIMENT STATIONS, 

 U. S. DEFT. OF AGRICULTURE. 



Congress? Let the others cease their machinations, 

 stand aside until they have amply demonstrated the 

 purity of the faith they profess with their lips: 

 "Why are you halting in the path of man? 



Is it your shoulder bears the human load? 



Do you draw down the rains of the sweet heaven, 



And keep the green things growing?" 



WHERE WE STAND. 



The follow ina letter from William K. Smythe, author 

 of -'The Conquest of Arid America," and founder of the 

 "Irrigation Age," tells some borne truths about us, which 

 we purpose using to good advantage: 



'D. H. Anderson, KII.. Chicago. 111. Sty Dear Sir I beg 

 to acknowledge receipt of your favors of July 14th and 

 27th, the latter including pamphlet (Influences in the 

 National Irrigation Program). 



"In your account of the beginnings of national irriga- 

 tion yon deprive your own magazine or ihe credit to 

 which It is entitled. 'The Irrigation Age' was Ihe instru- 

 ment of those who founded the organized Irrigation 

 movement, stood by its cradle, fought its battles, estab- 

 lished It as a force In the life of our times, and all with- 

 out money and without price. We had an idea. We be- 

 lieved it was big and righteous. We fought for it for all 

 we were worth. 



"WM. E. SM*THE." 



(Father of the National Irrigation 

 of Its flr*t presidents.) 



Congress, and one 



One dollar and fifty cents will secure for you one year's subscrip- 

 tion to THE IRRIGATION AGE and a finely bound volume of the 

 Primer of Irrigation which will be sent postpaid In a few months, 

 when volume Is completed. The Primer of Irrigation will be finely 

 Illustrated and will contain about 300 pages. Send post office or 

 express money order for $1.50 and secure copy of first edition. 



We have received a long article on the subject of 

 "Irrigation on the Planet Mars," which we are averse 

 to publish lest some one start an organization and col- 

 lect subscriptions for the benefit of the Martian suf- 

 ferers from land grabbing and water barons. 



COPYRIGHTKD, 1908, BY D. H. ANUEKSON. 



PLANT FOOIIS- 



CHAPTER VI. 



-THEIR NATURE UISTHI lU'TIOX AXD 

 EFFECTS IN GENERAL. 



There are four substances which are essential to 

 all plant food; without them few plants could live, 

 and what is surprising, they form a very large portion 

 of every plant in one form or another. These 

 substances are: Carbon, Oxygen, Hydrogen and Nitro- 

 gen. We shall take them up in rotation and briefly ex- 

 plain their origin, nature and action. 



CARBON. 



Carbon is generally known under the form of 

 coal, any kind of coal, but for experimental pur- 

 poses it is xisually wood charcoal that is consid- 

 ered the nearest approach to pure carbon, there 

 being none except the diamond which can be. called 

 actually pure or crystallized carbon. As, wood 

 charcoal, it is derived from willow, pine, box, and sevr 

 eral other woods, burned under cover so as to prevent 

 free access of air, and its manufacture is of great com- 

 mercial importance, kilns for its creation existing in 

 thousands of places throughout the United States, 

 where forests abound and wood is in plenty. It should 

 be borne in mind that this carbon, or wood charcoal, 

 is an essential element of the jplant, inasmuch as it 

 comes out of it by burning. Moreover it is all manu- 

 factured in the plant, extracted as part of its food 

 from the soil, or the air. 



Heated in air, charcoal, or carbon, as we shall 

 call it hereafter, burns with little flame, and is slowly 



ELMWOOD MEAD, 



CHIEF OF IRRIGATION INVESTIGATIONS U. S. DEPT. 

 OF AGRICULTURE. 



