.1 Botanical and Economic Study. 189 



CHAPTER VII. 

 Economic Considerations. 



THE importance of agriculture in laying the groundwork 

 of a true national prosperity is recognized by all. A 

 historical retrospect proves that with the decay of 

 agriculture in the States of Greece and Rome and the growth 

 of cities, the political habits of the people underwent a 

 decided change for the worse. Many writers have pointed, 

 therefore, with justifiable alarm to the last decennial census, 

 which shows that one fourth of the entire population of the 

 United States dwells in large towns and cities, and in many 

 places the most progressive part of the rural classes have 

 moved to the large industrial centres. Many forces conspire 

 to produce this change. A few of them are the diminishing 

 returns of agriculture, exorbitant transportation rates, natural 

 monopolies, unsatisfactory financial conditions and state 

 interference by partisan legislation. 



The law of diminishing returns is that the product propor- 

 tionally decreases with increased application of labor ; that a 

 time will be reached when, with intensive cultivation, the 

 land will be finally and irremediably impoverished. Some 

 decades ago very bad agricultural practice prevailed in the 

 United States ; one crop was grown exclusively on the same 

 piece of land. The cereals, wheat, rye and barley, which were 

 largely raised, sown successively for years in the same field, 

 rapidly exhausted the soil of the most valuable ingredients. 

 It is characteristic of starch and sugar-forming plants to take 

 large quantities of nitrogen from the soil. The plants are so 

 constituted physiologically as to need large supplies of nitro- 

 gen, potash and phosphorus for the proper storage of the 

 carbo-hydrates. These three essential elements are the most 

 difficult to restore to the land in sufficient quantities when 



