100 HANDY -BOOK OF HUSBANDRY. 



should be permanently built up with brick or stone, (as repre- 

 sented in Fig. 29,) the work being done solidly, but as rudely as 

 may be thought proper. The ditch below this outlet must be 

 of sufficient depth and capacity to keep it always free from ob- 

 structions. 



Mains and Sub-Mains. — Having procured substantial stakes 

 about eighteen inches long, stake out the main drain from the 

 outlet through the principal depression of the land, and if the 

 ground slope in other directions than toward this depression, or if 

 there be a broad valley with sloping land at each side, stake 

 other lines, connecting with the first, and running at the bottom 

 of the various slopes, or in the middle of the secondary depres- 

 sion, so arranged that they shall have a uniform descent for their 

 whole distance. The proper arrangement of these collecting 

 drains requires more skill and experience than any other branch of 

 the work, as on their disposition depends, in a great measure, the 

 economy and success of the undertaking. 



Lateral Drains. — Having so arranged the mains and sub- 

 mains that water flowing down the various slopes, in the line of 

 steepest descent, would reach them without materially changing 

 its course, stake out parallel lines, forty feet apart (the first line 

 being twenty feet from the boundary of the land to be drained) 

 running directly down the slopes in the lines of their steepest 

 descent, or as nearly so as is consistent with tolerable simplicity 

 of arrangement, and connecting with the main lines at their feet. 

 The stakes which indicate the points at which the laterals strike 

 the main lines, may be marked so as to be easily recognized as 

 Indicating these points, and the original stakes of the main lines 

 may be taken up and reset at points mid-way between the laterals, 

 or at shorter distances, if necessary. On the lateral lines, they 

 should be at uniform distances; on the main lines, they should be 

 as nearly so as possible. 



Mapping. — Commence at the lower end of the main line and 

 mark the stakes consecutively y/, Aa^ Ab^ Ac^ etc. Then, sup- 

 posing sub-mains to unite with the main line at stakes h and r, 

 mark the stakes of these Ab \^ Ah 2, Ah 3, etc ; Ac \^ Ac 2^^ 



