2O4 



FARM DEVELOPMENT 



decided upon in working out the survey notes. In grad- 

 ing with water, the safest way is to go too shallow rather 

 than too deep, as it is not always practicable to fill in 

 with loose materials under the tiles in running water. 

 This can, of course, be done by using gravel or coarse 

 stones which will not be displaced by running water. 

 Many practical ditchers require no survey whatever if 

 there is water in the ditch, and ample fall, since they 



Figure 94. Ten men performing successive operations in opening the ditch, grading the 

 bottom and filling the ditch. 



can lay out the general plan of a drain with the eye, and 

 by carefully using the water as an indicator can make a 

 thoroughly practical drain. 



The triangular tile drain grader, shown in Figure 95, 

 may be made any suitable length, as 10, 12 or i6 l / 2 

 feet. When the lower board is level, a large nail is driven 

 in its upper edge immediately under the point of the 

 plumb bob. If it is a rod long, it may be adjusted to 

 grading 2, 4, 6, 8, 10, 12, etc., inches per 100 feet by 

 using blocks one-third of an inch thick under one end, 

 driving a nail under the point of the plumb bob each 

 time the upper end is raised by the addition of one of 



