No. 4.] HINTS ON LAND DRAINAGE. 377 



a strip of tarred paper, oil cloth or heavy burlap (about an 

 inch and one-half wide for small tile and two inches or more 

 for the larger sizes) over the top and sides of each joint, in 

 close contact with the outer surface of the tiles. Strong, 

 tough turf, with most of the soil shaken out, may be used 

 for the same purpose. 



In quicksand especial care must be observed to lay and 

 keep the tile in their proper grade and line, which may best 

 be done by first placing and securing in the bed of the trench, 

 at the true and established grade of the drain, a strip of 

 board or plank about two inches wider than the outside 

 width of the tile itself. At each joint of the boards a splic- 

 ing piece about twenty inches long should be laid along the 

 under side of the abutting ends of the boards, and both boards 

 nailed thereto. Upon this continuous foundation the tile are 

 to be laid in a true line, and where further security against 

 lateral movement is required ordinary lath may be placed 

 on edge along and against each side of the tile, the joints 

 being first covered with strips of tarred paper or other 

 material, as above described. In back-filling the trench the 

 coarsest material that is available should be first used in con- 

 tact with the tile, the constant purpose to be kept in view 

 being to keep the quicksand out of the joints by placing 

 around the tile such material as will permit the admission 

 of water only. 



Where gravel or coarse sand may be easily and cheaply 

 obtained, one of the best methods of laying tile in quicksand 

 or soft clay is to excavate the trench three or four inches 

 below grade, and fill up to the grade with gravel or coarse 

 sand ; then lay the tile upon the gravel bed in the usual 

 manner, cover them with the same material to a depth of 

 three or four inches, and complete the back-filling of the 

 trench as before, with the coarser material toward the 

 bottom. The result is a tile drain laid in a material not 

 easily displaced by external influences, and surrounded by 

 a continuous filter which will admit water with the utmost 

 freedom and exclude silt. Where the cost of obtaining such 

 coarse material is large, its use may be confined to surround- 

 ing the join ts only, to a distance of two or three inches ; but 



