224 INDEX. 



PAGE 



Commissioners, work of 206 



Compass, description of 79 



, how used 80 



notes, how kept S3, 84 



Computing excavations, method of 169 



Construction of drains, difficulties of 109, 110 



Contour lines, description of 65 



map 69 



survey , 66 



Contracts for construction work 120 



Contract, form of ^ 125 



Copies of maps, how made loi, 102 



Cost, estimates of 209 



of digging ditch and laying tile 212 



of hauling and distributing tile 211 



of superintending work 212 



Crops, increase of , ,,.,.,.. 9 



Cross-drains for roads 193 



Cross-sectioning, form of book for 168 



, method of , 168 



Culverts, sewer-pipe for • 193 



Curve, degree of 154. 



, how run 156 



, proper, for open ditches 155 



Curves in tile-drain Imes 72 



Cut for ditches, how found 86 



Datum, common , 77 



plane 50 



Declination of magnetic needle, how corrected. 83 



Depth of drains, discussion of , 89 



Ditch for tile, how to dig 106 



Ditches, bottom width of , . .... 158 



, curvature of 154 



, filling. . . . • 1 14 



, special forms of • 177, 178 



Divide, how to find natural 2cx> 



Drafting instruments 96 



Drainage basin, how designated. , 64 



Drainage district, l^undary of 199 



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