EXPERIMENT STATION BULLETINS. 503 



If when a section of tile is laid into place, it does not fit tightly 

 against that already laid, it is usually found that by rolling it to the 

 right or left, it can be made to fit so tightly as to practically prevent 

 the passage of soil particles except quick-sand or fine silt. Sometimes 

 this cannot be done and a new piece of tile must be substituted. A piece 

 that cannot be made to fit in one place will frequently readily fit in 

 another place in the same line of tile. 



As the work of laying the tile progresses the workman should shovel 

 in upon the tile a sufficient amount of loose soil to settle down about 

 the sides and partly or wholly cover the tile. This holds the tile in 

 place until the filling can begin. Sometimes, instead of shoveling in 

 soil from the surface some soil is loosened from the walls of the ditch 

 to fall upon the tile and accomplish the same results. This covering of 

 the tile is called blinding. 



When the last tile of any drain is laid, a stone or piece of brick or 

 pieces of broken tile should be laid against the upper end and soil 

 shoveled against it to hold it in place. This keeps the soil from working 

 into the end of the tile. 



FILLING THE DITCH. 



The filling may proceed as rapidly as the tile are laid and anchored. 

 Sometimes it is done by hand. Sometimes it is hastened by the use of 

 a plow or a scraper. When a plow is used an evener must be provided 

 that is sufficiently long to allow the horses to walk on opposite sides 

 of the ditch. When the plow is used, the bars and stakes must first 

 be removed. The team is driven the length of the ditch or for a con- 

 siderable part of it at a time and the soil is plowed back into the ditch. 

 The plow is run back empty. 



Only the board scraper is convenient for filling. The team works on 

 one side of the ditch and the man and scraper on the other. A chain 

 or rope must be used between the team and scraper and it must be suffi- 

 ciently long so that tlie team will not be backed sufficiently near the 

 ditch to result in accident. 



When plow or scraper is used it is usually necessary for a workman 

 with a s-hovel to finish the work. 



FINISHING THE OUTLET. 



The outlet of the main drain, should be completed with two things in 

 view: 



1. To provide against its destruction by frost, flood, tramping of 

 live stock, etc. 



Usually it is best to replace the lower six or eight feet of tile with 

 glazed sewer pipe or sometimes with a piece of iron pipe of proper size. 

 This should be done of course when the work of laying tile begins. 



To prevent the washing or tramping away of the earth about the out- 

 let and to give strength, a wall of masonry or cement should be built 

 something as shown in Fig. 24. 



2. Means should be provided to prevent vermin, such as rats, etc., 

 from entering the mouth of the drain. To accomplish this a screen 

 of woven wire or a grate of iron bars mounted on or in a strong wooden 

 frame should be firmly set against the outlet. See Fig. 25. 



