Digging Ditches. 



321 



a rise of but G inches. It is clear that to hold a single grade, 

 making the upper cud of the ditch 2.92 feet deep, would 

 require a greater depth in other portions than necessary. 

 But if the grade is changed at the 600 foot station so as 

 to give a fall of 



' 5 _ f fc = .1 ft. per 100 ft. 

 o 



a sufficient depth will be secured and labor in digging 

 saved. 



FIG. fS'J. Showing the ditching line and the commencement of digging. 



393. Ditching Tools. In digging a ditch it is a matter of 

 first importance to have suitable tools; and whatever else is 



