Contents xxi 



PAGES 



The Use of the Windmill in Drainage. Arrangement for 



winter pumping Subirrigation as an adjunct 463, 464 



Lands which must be Surface Drained. Ancient lake bot- 

 toms underlaid with clay Sections where there are no 

 natural surface outlets 464-466 



CHAPTER XIII 



PRACTICAL DETAILS OF UNDERDRAINING (pages 467-492) 



Methods of Determining Levels. Kinds of levels 469-471 



Leveling a Field. Making contour map Using the level. . 471-473 



Location of Mains and Laterals. Securing the greatest 



fall 474-476 



Staking Out Drains. Grade pegs 476, 477 



Determining the Grade and Depth of Ditches. Method of 



marking stakes for use of ditchers . 477-481 



More than One Grade on the Same Drain 481 



Digging the Ditch. Tools used Method of procedure 



Methods of filling 481-488 



Cost of Under dr ainin g . For mains For laterals 489-491 



Peat Marshes 491, 492 



