THE BLESSING OF ARIDITY 



arts. Among the silent witnesses which have survived 

 the centuries to testify to the engineering skill and 

 the perfection of social organization of those who were 

 swept into oblivion by nameless calamities, are great 

 irrigation canals, portions of which are even yet so true 

 and substantial as to serve the uses of to-day in con- 

 junction with modern works. There are such instances 

 in Arizona. 



The accepted explanation of the choice of the arid 

 land by the ancient races is that they sought security 

 against savage enemies, both animal and human, which 

 infested the forest. The theory is purely sentimental 

 and quite inconsistent with the slight but conclusive 

 evidences of their superior intelligence and courage 

 which yet survive. The reasonable explanation of the 

 mystery of ancient civilization is that the arid lands 

 were chosen because they were infinitely better than the 

 humid lands, and because they presented conditions 

 much better suited to the industrial polity of the people 

 and the age. 



In searching for the clue of this mystery Professor 

 Hilgard has developed facts which tend to upset other 

 accepted theories. It has long been conceded that cer- 

 tain arid districts are the richest spots on the surface of 

 the globe. ' ' The valley of the Nile/' for instance, is a 

 phrase which is everywhere taken as a synonym of ex- 

 traordinary fertility. The richness and durability of 

 the Nile lands, which have supported for centuries an 

 average population of little more than one and one-half 

 persons to each acre of cultivated soil (a density of set- 

 tlement which would give Texas a population of over 

 one hundred and sixty millions), has been ascribed to 



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