PIPES AND TILES. 51 



which might otherwise split the covering. These pipes 

 are placed in the channels beneath the roads or paths, and 

 the earth is heaped over them gradually, sloping in each 

 direction. These pipes should be used wherever there is 

 danger that earth may fall into the channels, or that they 

 may be injured by rough usage. If made of seasoned 

 oak plank two inches thick and bedded in waste lime or 

 mortar, they will last many years without deterioration. 



CHAPTER VI. 



IRRIGATION BY PIPES AND TILES. 



Many elaborate improvements have been made within 

 the past few years in the practice of irrigation. The 

 costly character of these improvements renders them in 

 applicable to any lands except those devoted to crops of 

 great value. The minimum value of the crops that may 

 be profitably raised by the methods of irrigation here re 

 ferred to may be placed at $400 per acre. In some cases 

 where the profitable use of land depends entirely upon 

 these costly plans, this minimum may be reduced con 

 siderably. Thus, rather than have land idle it may pay 

 to expend a permanent capital of $250 per acre, the year 

 ly interest of which, with the annual cost of water, and 

 labor, may on the whole result in a yearly outlay of $100 

 per acre, to produce crops which may realize $250 to $300 

 per acre. Eor a market garden these amounts are much 

 less than the average value of the crops produced, and 

 many seasons occur in which the losses by reason of dry 

 weather at critical periods will amount to more than or 

 many times the total value of the improvements here to 

 be described. It is therefore a question of serious import 

 to market gardeners, small fruit raisers, and the proprie- 



