IRE IRRIGATION AGE. 181 



the reader is again referred to that publication. The principles and 

 practices there presented are also of wide applicability to the use of 

 water for field and garden crops, and should be considered therewith. 

 Distribution by a system of underground pipes with standpipes, 

 hose, and sprinkling devices js not widely practicable, because of the 

 cost of the outfit. It is true that in intensive horticulture the return 

 may be so great from a small area that the investment may be found 

 profitable, but such investment is out of the question for common 

 crops, and the cheaper way secures a welcome saving in the cost of 

 production of even the highest- priced commodities. One must be 

 quite sure of his market when he makes large investment in facilities 

 for production, and the fact that market gardeners and small fruit 

 growers in irrigated regions never resort to the showering method is 

 a demonstration that the risk involved in such large investment is 

 unnecessary. For the growing of home supplies or commodities for 

 sale in low markets the investment required for showering would 

 practically prohibit resort to irrigation. 



LOCATING THE FARM DITCH. 



Contour lines are prime factors in all systems of distribution of 

 water by natural flow, or, as they are commonly called, gravity sys- 

 tems. For this reason pains should be taken even in small undertak- 

 ings to mark out these lines with approximate accuracy. The use of 

 the triangle for work of this kind has already been suggested, From 

 the highest point on the land to which the water can be brought the 

 main supply ditch should be laid out as nearly along a contour line as 

 will give sufficient fall for the water to flow. If this main ditch be 

 carefully laid out and well made the water can be taken out and car- 

 ried -by lateral ditches or flumes along lines of nearly equal elevation 

 in any direction in which there is a slope away from the main ditch, 

 or it may be dropped from the main ditch through pipes or wooden 

 flumes to lower lines or ridges from which distribution can be made. 



By studying the relations of the different surfaces, or irrigation 

 faces, to each other and correcting visual impressions with the use of 

 the triangle, the farmer can carry the water to every point of a very 

 uneven piece of land and successfully avoid both cutting and overflow 

 throughout his whole system of ditches and flumes, This is done by 

 getting even grades and the least fall that will move the water. The 

 general tendency is to give ditches too great a fall. 



DEVICES FOR TURNING WATER FROM DITCHES. 



The crudest way to turn water from a ditch is to make a cut in the 

 side with a spade and throw the dirt into the ditch to make a dam. 

 Some simple home-made devices will obviate the manifest disadvan- 

 tages of this method. Three will be described, and others will sug- 

 gest themselves to the ingenious irrigator. 



