64 TILE DRAINAGE. 



carefully noticing the natural courses, for one or two sea- 

 sons, in high water after heavy rains or thaws. 



THE DIRECTION OF THE LATERALS. 



The same rule holds in regard to laterals. They should in 

 general follow, but straighten and improve, the courses taken 

 by surface-water in time of freshet or flood. If, however, 

 the slope is not very rapid, convenience may lead us to vary 

 the laterals slightly from the direct line down the slope. In 

 my own first thorough drainage, convenience amounting 

 almost to necessity seemed to demand this. The lield shown 

 in Fig. 8 was set out with rows of young apple-trees as an 

 orchard. These rows, of course, for convenience, were set 

 parallel to each other and to the sides of the field. But the 

 exact slope was slightly angling with the sides, as shown by 

 the darts in Fig. 8. Now, if the laterals had followed this 

 exact course they would have run into or under apple-trees 

 at many points, and so they were laid parallel to the side of 

 the field to which the slope of the field was most nearly 

 parallel, and were laid just half way between the apple-tree 

 rows. This is almost a necessity in an orchard, and is a 

 great convenience, often, in other fields. As I shall show in 

 the chapter." How to Drain, "one can economize very greatly 

 in the expensive hand labor of digging, by plowing the field 

 so as to leave a dead-furrow T where each drain is to be, or by 

 running two deep furrows, one in the bottom of the other, 

 with a strong team four horses if necessary before digging 

 at all by hand. I have often saved much in this way as well 

 as by filling in with the plow, both of which can best be done 

 if the drains are parallel with some side of the field, as the 

 land can be " plowed out " before digging, and " plowed in " 

 after laying the tiles ; and so in my own practice I have tried 

 to follow two general rules in thorough drainage or, rather, 

 one rule, except as modified by a second ; to wit : 



First, run the laterals as nearly straight down the slope as 

 may be done consistently with the second rule ; to wit : 



