206 CALIFORNIA FRUITS: HOW TO GROW THEM 



pegs. Drive a peg at the starting point with its top say six inches 

 from the general surface of the ground. Hold one end of the 

 leveling apparatus above this peg by exactly that amount which 

 the line rises per each instrument-length (B C), and swing the 

 other end around into the direction from which the ditch is to 

 come, until, when level, it is just six inches above the ground. 

 Drive a peg here, which will, like the first, be six inches high, and 

 proceed as before. Care should be taken to give the top of each 

 peg exactly the correct elevation. The level must be horizontal 

 when resting on any peg, and raised exactly that amount which the 

 line rises per level-length, above the preceding peg. It will be 

 found convenient to use a carefully-prepared block to hold on the 

 top of each stake at the rear end of the level instead of trusting 

 to measurement each time. 



Locating Contour Lines for Checks or for Distributing Ditches. 

 This work can be done with the aid of the level above described. 

 For instance, to locate a contour (a line of equal elevation), as 

 required in the construction of a check levee, drive a peg until 

 its top has a convenient elevation from the ground, say one foot. 

 Rest one end of the triangle on this peg and swing the other 

 around until, when B C is horizontal, this other end has exactly the 

 same elevation from the ground as the top of the peg. At this point 

 drive a second peg and proceed as before. If the tops of the pegs 

 be chosen as the height of the levee, they may be retained as grade 

 stakes as well as line stakes for the embankment. 



Storing Water from Small Sources. For individual uses quite 

 a respectable water supply can sometimes be developed from 

 apparently mean sources. This can be done by clearing out and 

 opening up hillside springs, and often by tunneling into the hillside 

 to intercept subterranean water-flows, or by pumping from a well. 

 Even a small spring, yielding but two quarts per second, would be 

 sufficient to irrigate several acres in fruit trees. To derive the 

 greatest benefit from small springs, however, a reservoir is neces- 

 sary, in which the flow of twelve to twenty-four hours, or even a 

 longer period, can be accumulated, and then discharged as required. 

 It is by using water in driblets that many springs are wasted. 

 A spring supplying even one and a half inches of water would be 

 wholly swallowed up by a thirsty soil within two hundred feet of 

 its source, when, by arresting the flow and accumulating it in a 

 reservoir and discharging at intervals in a volume four times as 

 large, it would more than cover eight times the surface. A spring 

 flowing two quarts per second will discharge forty-three thousand 

 two hundred gallons in twenty-four hours. This would require a 

 reservoir forty by twenty feet, and seven feet deep, or double that 

 width if the depth is decreased one-half. The shallower it can be 



