142 IRRIGATION FARMING. 



watching being necessary, and no constant labor with the 

 shovel, as when water is applied from open ditcho. 

 Sometimes a substantial flume of brick is laid in place of 

 one of wood, and a square vitrified pipe with openings 

 in the side is also highly thought of. A section of this 

 terra cotta head ditch is presented in Figure 51. 



Into this flume is turned from the ditch an irrigat- 

 ing head of 20, 25 or 30 inches of water, generally about 

 20 inches. This is divided by the holes into streams of 

 from one-sixth to one-tenth of an inch, making from 120 

 to 200 streams. These are run across the tract in small 

 furrows leading from each hole. From five to seven fur- 

 rows are made between two rows of trees, two between 

 rows of grapes, one furrow between rows of corn, pota- 

 toes, etc. It may take from fifteen to twenty hours for 

 one stream to get across the tract. They are allowed to 

 run from eighteen to "seventy-two hours. The ground is 

 thoroughly wet in all directions and oftentimes three or 

 four feet deep. As soon as the ground is dry enough, 

 cultivation is begun and kept up from six to eight wei-ks 

 before water is used again. For trees a year old one fur- 

 row on each side of the row will do, for two years old 

 two furrows, and so on. 



In many places the outlet from the underground 

 head flume is through a series of stand pipes. An im- 

 proved measuring penstock consists of a four-inch iron 

 .st and pipe resting on a six-inch vitrified service pipe. 

 At the summit of this measuring standpipe is a sliding 

 gate on which is a scale so arranged that the amount of 

 water flowing through it can be measured by simply read- 

 ing the scale. A valve inside the standpipe is operated 

 by a screw attachment and admits the proper amount of 

 water, while it can be locked by a simple device. Out- 

 side the standpipe is a pressure gauge which shows the 

 head of water on a measuring slot with a glass face. 

 This contrivance is used in measuring the patron's appor- 



