DRAINIXG. 48 



creeping things will soon take possession of them and render 

 them worse than useless ; but carefully protect the upper ends 

 J of the drain with bricks or flat stones, cover the joints with 

 turf, or, in stone drains, with flat stones, and put an iron grating 

 over the outlet, and you may feel pretty secure against obstruc- 

 tions. But the further precaution (as we have before stated) 

 should be taken of accurately marking the entrance of each 

 : minor to the main, so chat if there are obstructions their posi- 

 ■ tion may be ascertained. The outlet should be of stone so as 

 not to be easily destroyed. 



If it is nearly on a level with the bed of the stream into 

 which it enters, a basin should be dug, in order that all sedi- 

 ment from the drain may be deposited in it and not set back 

 into the drain. Care should be taken to have hard-burneJ 

 tiles, as the crumbling of one tile will obstruct a whole drain, 

 as will also a carelessly laid tile. Roots obstruct cobble stone 

 and brush drains, but can hardly penetrate hard-burnt tiles or 

 Hat stones. 



The Drainage of Swamps sometimes requires very dif- 

 lerent treatment from that previously described. If the wettest 

 I >art of the swamp is about the edges, a deep trench should be 

 cut, not through the center, but around the outside, with an 

 outlet at the lowest practicable point ; after this drain has done 

 its work of removing the surface water, shallower drains may 

 be laid sixty to one hundred feet apart, and if the soil is clayey- 

 auger holes should be bored down to the gravel beds. These 

 auger holes should be a little to one side of the current of the 

 drain. Thus far, we have been instructing the farmer to con- 

 .-truct drains, with the means always at his command; we 

 now come to the description of the various Draining Ma- 

 chines in use in different parts of < ur country. 



The Mole Plow works well in stiff clay soils free from 



