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HANDY-BOOK OF HUSBANDRY. 



is then slipped along until only one-half of its length is under the 

 tile. The next tile has its nose inserted in the unoccupied half 

 of the collar, and one-half of its other collar is drawn forward 

 to receive the next tile — and thus to the lower end of the drain. 

 The trimming of the ends of the tile, and the perforations in the 

 tiles of main drains to admit the laterals, are made with a pick 

 (Fig. 40). To make a hole in the tile, use the pointed end of 

 the pick, chipping around the circumference of the hole until the 

 center-place falls in. Collecting drains should be laid a little 

 deeper than the mouths of the laterals which discharge into them, 



(allowance for this having 



been made in the original 



grading,) that these may be 



admitted at the top of the 



main. When the lateral 



Fig. 41.— Lateral Drain entering at Top. and the main are of equal 



size, the best way to make the connection is to substitute a long 



pipe in place of the collar, making a hole at the top of this, to 



admit the lateral, as shown in Figs. 41 and 42. 



Silt Basins. — In new drains there is always some earthy 

 matter (silt) in the water which flows through the pipe, — the 

 looser earth about the joints is carried in, in small quantities, dur- 

 ing the early action of the drain. If the fall of the drain is 

 irregular this silt may be carried in suspension in the water, where 

 the current is rapid, and deposited 

 in the depressions, or more level 

 parts, where the flow is sluggish, 

 and cause the obstruction of the 

 drain, which is thereby rendered 

 worthless. In ordinary soils, the 

 amount of silt entering at the 

 joints of the drain, will, if the fall 

 be regular, cause no inconvenience, being either all carried 

 out at the mouth of the drain, or deposited throughout its whole 

 length to a depth so slight as to be of little or no consequence. 

 If, on the other hand, it becomes necessary to diminish the fall 



Fig. 4Z. — Sectional View of Joint. 



