6 MODERN HIGH FARMING. 



those comprised in its very hottest parts the tract which stretches 

 from the Isthmus of Panama to Mexico in the northern, and to Peru 

 in the southern tropic. 



If we momentarily set aside to be dealt with later on the 

 questions of geological and chemical varieties of soil, we may at 

 once assume that the two regulating causes of fertility are combined 

 heat and moisture the f ruitf ulness or sterility of the land being 

 dependent upon their abundance or deficiency. Now as regards 

 moisture, neither in North nor in South America does one great 

 river empty itself into the Pacific the whole of them being upon 

 the eastern coast ; and as regards heat, nature has been equally 

 partial in its endowment of the west. Whether the natural differ- 

 ence of temperature resulting from this curious phenomenon forms 

 part of some universal scheme, or whether we are dealing with a pe- 

 culiar instance, we will not stay to discuss ; the fact and its influence 

 upon the early history of this country are indisputable the two 

 great conditions of fertility not having been naturally united in any 

 part of the entire continent north of Mexico. The primitive inhab- 

 itants were, therefore, in this difficulty: on one side they wanted 

 heat, while on the other they had no irrigation ; and the result was 

 that until the sixteenth century, when the acquired knowledge of 

 Europeans was brought to bear upon the difficulty, there existed no 

 agriculture, no accumulation of wealth, and no progress north of the 

 twentieth parallel, even toward that rough civilization so easily 

 attained by the nations of India and Egypt. For a direct contrast 

 to what went on in the north, we have now only to turn to the 

 narrow tract of land lying south of the twentieth parallel, of which 

 the peculiar configuration caused by the contraction of the continent 

 until it reaches the Isthmus of Panama secures to it a large extent 

 of coast. 



This southern part of North America thus assumes the character 

 of an island with that feature of an insular climate, the increase 

 of moisture consequent upon the watery vapor arising from the sea, 

 and the augmentation of rainfall natural to its vicinity. It was 

 therefore the only portion possessing a natural combination of the 



