GRADING THE DITCHES FOR TILE. II9 



and the subsoil is clay, there is no occasion for the use 

 of the silt-basin in land drainage systems. Its use for 

 a catch-basin for conveying surface water into tile 

 drains under certain conditions will be described here- 

 after. 



Diggmg Tile Ditches with Machines, 



Many machines of different patterns have been pat- 

 ented, tried, and have failed to displace hand labor in 

 digging tile ditches. The difficulties to overcome do 

 not seem insurmountable, nevertheless the history of 

 such machines discloses partial successes which for a 

 time promised well, but in the end did not meet the re- 

 quirements of the work in all kinds and conditions of 

 soils. Ploughs of different patterns have been used to 

 aid the spade by loosening the earth in the bottom of 

 the ditch, thereby diminishing the labor of excavating 

 somewhat. The machines which have dug the ditch 

 to its full depth at one passage have given the most 

 satisfactory results. The ditch is left completed to 

 grade and ready for the laying of the tile, the exca- 

 vated earth is left loose and ready to be easily back- 

 filled and the grade is more easily and accurately made 

 than by a machine which excavates by many passages 

 over the ground. 



One of these machines which gives excellent results 

 at the present writing and has been more successfully 

 introduced than its predecessors is distinctively a 

 traction ditcher. It is propelled by steam power 

 which operates a cutting wheel and at the same time 

 moves the machine forw ard by traction, excavating a 



