70 



COXSTRUCTION OF DRAINS. 



Second, as to the way in which they should be 

 made, and the materials to be used. 



a. The ditch should of course be wedge-shaped for 

 convenience of digging, and should be smooth on the 



bottom. 



6. Where stones are used, the proper width is about 

 six inches at the bottom. Small stones should be 

 selected, or large ones broken to about the size of a 

 hen's egg, and the ditch filled in with these to a depth 

 of nine or ten inches. The earth is apt to fall into 

 the cavities among larger stones, and mice or rats 

 make their burrows there : in either case, water finds 

 its way from above, and washes in dirt and mud, soon 

 causing the drain to choke. With small stones, 

 choking from either of these causes can not take place 

 if a good turf be laid grass side down above the stones, 

 and the earth then trampled in hard. Cypress or cedar 

 shavings are sometimes used, but are not quite so safe 

 as a good sound turf The water should find its way 

 into the drain from the sides, and not from the top. 

 The accompanying figure represents the 

 arrangement of the stones : a is the turf 

 on top; if the water enters at the sides 

 h, b, it comes in clear, having filtered 

 through the soil, and depositedevery thing 

 in the way of mud which might tend to 

 choke the drain. Some farmers prefer to 

 make stone drains like fig. 4, having two 

 flat stones laid against each other at the 

 bottom so as to form a sort of pipe, and 

 filling above them with small stones as 

 before. In very swampy soft ground, it 

 is sometimes necessary to lay a plank or 

 slab in the bottom of the drain, before 

 putting in the stones. This is to prevent 

 them from sinking, and making an un- 

 even bottom, before the soil becomes dry 

 enough to be firm. 



Fig. 3. 



