Field Drainage. 3 7 



the summer suns. During the severe drought of 1887, 

 Mr. T. R Hunt, Assistant Professor of Agriculture at the 

 University of Illinois, made some experiments in order to 

 ascertain the comparative quantities of moisture in drained 

 and undrained soils. The average of forty samples of earth, 

 2 feet in depth, taken from undrained fields was 13*2 per 

 cent, while in those taken from drained land it was 14' i per 

 cent. Probably the draining had been done at a small depth, 

 or the difiference would have been greater. The small differ- 

 ence in favour of the drained land, however, may serve to 

 dispose of the objection to draining, that it renders land less 

 able to bear drought 



Thus it will be seen that, other considerations apart, pipe- 

 drains should be laid sufficiently deep to remove the surplus 

 water from the roots of the plants, yet not so deep as to retard 

 the moisture from rising, when wanted, from the supply stored 

 up in the stratum below the drains. 



Drainage also acts mechanically on a tenacious soil, and 

 assists in the discharge of the rainfall and the improvement of 

 the texture of the ground by contracting it, and thus increas- 

 ing the number and size of the larger pores, making more 

 numerous crevices. That this is the case may easily be 

 proved by taking a roll of wet clay, i foot in length, and dry- 

 ing it, when it will be found to shrink in length about half an 

 inch, which, in a drain 100 feet long, would be equal to 

 increased spaces which, if added together, would measure 

 4 feet 2 inches. The value of these crevices and contractions 

 may be more fully realised by examining the appearance of 

 two seeds of corn, the one of which has been sown in well^ 

 drained land and the other in a hard, cold soil. In the former 

 case, the rootlets are able to travel in all directions in search 

 of food, and the plant is strong and healthy ; in the latter the 

 delicate fibres of the roots are unable to force their way 

 through the hard ground, and the plant, lacking nourishment, 

 is stunted and unhealthy. 



