THE FARMER OF TO-MORROW 



more than fifty years turning over his 

 prophecies. He said that, while population 

 increases in a geometrical progression, the food 

 supply increases in arithmetical progression. 

 Vice, crime and disease slow up the unequal 

 race; nevertheless population must inevitably 

 overtake the food supply at definite periods, 

 and the only means of evening matters again 

 is starvation. It was a mere matter of mathe- 

 matics. Regardless of how many million 

 acres of unproductive land there existed at 

 that time in the new countries, the day must 

 inevitably arrive when the world would be face 

 to face with the limits of production of its 

 granaries. 



Some fifty years after this doctrine went 

 abroad, Baron Justin von Liebig came for- 

 ward with a theory which seemed to postpone 

 for a time at least the impending catastrophe. 

 He said that crops remove certain ingredients 

 from the soil, but the soil may be made to 

 produce indefinitely, even at a greatly acceler- 

 ated rate, simply by adding these ingredients 

 in chemical form. 



He named these nutrients of which the soil 

 would be despoiled by constant cropping 

 nitrogen, potash and phosphorus, and showed 



