72 Irrigation and Drainage 



by means of latent ducts or sluices, to moisten the 

 lands in the lower levels through which they passed. 

 Some of these aqueducts were of great length. One, 

 that traversed the district of Condesuyos, measured 

 between 400 and 500 miles. Thej r were brought from 

 some lake or natural reservoir in the heart of the 

 mountains, and were fed at intervals by other basins 

 which lay in their route along the slopes of the Sierra. 

 In their descent a passage was sometimes opened 

 through rocks, and this without the aid of iron tools ; 

 impracticable mountains were to be turned, rivers and 

 marshes to be crossed in short, the same obstacles 

 were to be encountered as in the construction of their 

 mighty roads." 



THE EXTENT OF IRRIGATION 



From what has been said regarding the antiquity of irriga- 

 tion, we shall not be surprised to find that its practice has found 

 a geographic range which is commensurate with its distribution 

 in time. We look first to European countries, and begin with 

 Italy, where irrigation certainly had a very early development, 

 and has ever since been yearly practiced in rural life. 



In the valley of the Po, naturally very fertile, but made more 

 so by thorough and systematic irrigation, water is extensively 

 applied to almost all crops. To convey some idea of the general 

 practice of irrigation in the Po valley, it may be stated that on 

 August 7, 1895, while riding by rail from Turin to Milan, between 

 Chivasso and Santhia, a distance of 18.5 miles, the writer saw 

 water being applied to 100 different fields of maize by as many 

 different parties, and the fields ranged in size all the way from 4 

 to 20 acres. Wheat, barley, hemp, rye-grass, clover, rice, and 

 maize are among the field crops generally and extensively irri- 

 gated in this part of Italy. So, too, very extensive mulberry 



