Contents xxi 



PAGES 



TJie 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 UNDERDEAINING (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 draining . For mains For laterals 489-491 



Peat Marshes 491, 492 



