260 



FARM DEVELOPMENT 



Figure 156. Supply ditch as made with reversible 

 road machine or with plow and scraper, as in 

 Figures 117 and 155. 



The biped level shown in Figure 158 is used in map- 

 ping out field laterals around slight elevations. Laterals 

 nearly level make it possible to take water out through 

 small openings in their banks into the furrows between 



rows of cultivated 

 plants or trees or upon 

 grain or meadow fields. 

 In constructing this 

 homemade level it may 

 be adjusted to read 

 level by means of a 

 screw arrangement, or 

 even a wedge, to raise or lower one end of the spirit level 

 on the rail, and two stakes 16^2 feet apart, driven at first 

 as nearly level as the eye can judge. By repeated trial, 

 by reversing ends and driving down the higher stake, 

 the tops of the stakes 

 can be made the same 

 height and the instru- 

 ment adjusted to read 

 level. The extension 



162" at One end Can then Figure ISZ. Ditch for farm laterals as plowed 

 S <* w*w* QUt by meang of ordinary stubble plow or double 



be lowered according moldb ard or finished by means of a V-shaped 



to the grade to be given 



the ditch, as follows : One-eighth inch per rod giving a 

 grade of 40 inches per mile; %, 80 inches; %, 120 

 inches, or 10 feet, etc., as regulated by the figures on the 

 adjustable leg, shown in Figure 160. 



To mark out a grade for a ditch leading from the sup- 

 ply ditch, place the shorter, stationary, leg at the point of 

 taking in the water; dig a place for the longer, adjustable, 

 leg to a depth at which the bulb will read level. Moving 

 the leveling device forward place the short leg in the last 

 hole and dig another hole sufficiently deep so that when 

 the long leg is placed in it the bulb again reads level. By 

 following a slope requiring holes of nearly equal depth 



