140 PREPARATION OF LANDS. 



trench and filling up to a certain depth with small brush. 

 When this is attempted, the sticks should all be laid with 



the larger ends down, as 

 shown in figure 12. The 

 Fig. 12. brush is then thoroughly 



pressed down and covered over with sods 

 with the turf or grass side down. This 

 is better than none ; but it is never to 

 be recommended where good tiles can 

 be got. The same may be said of log- 

 drains which are made by laying down 

 two logs in the trench with a third upon 

 them, as in figure 13. The earth must 

 be pressed down solid over a stone, brush 

 or log drain. 



436. The distance apart at which the 

 drains should be laid will depend on the character of the 

 soil. In a soil which is stiif and holds water long, it might 

 not be well to have them more than twenty-five feet apart, 

 while a more porous soil might be sufficiently drained 

 if they were thirty or forty feet apart, or even more. 



437. The depth of the trench must depend somewhat 

 on the distance between the drains. Trenches three feet 

 deep and twenty feet apart, have been found to do as well 

 as those &quot;five feet deep and eighty feet apart. In general 

 the depth should be from three to four feet. 



438. Thorough draining makes the soil more open and 

 causes ii more free circulation of air through it, thus 

 prevent in&quot;- it from drying up so soon. The air is at all 

 tim^S clmi-M-ed with moisture 1 , and as it comes in contact 

 with the particles of soil, this moisture is condensed and 

 i!ep.sifiMl there, just as we sot; it deposited on the cold 

 sides of a pitcher of ice water in a hot day. Drainage 



