150 



LAND DRAINAGE 



necting lateral will be governed, as above, by the sizes of 

 tiles used. 



200. Making openings through tile. An opening 

 through the wall of a section of tile is easiest made with 



FIG. 62. A top connection in cross-section. A stone closes the lower 

 end of the lateral. 



what is called a tile pick. With care the opening can be 

 made with a small-headed hammer, such as is shown in 

 Fig. 59, by first knocking a small opening in the wall 

 about where the center of the finished opening should be, 

 and then carefully chipping away the edges of the opening 

 by light blows with the hammer until it is made suffi- 



FIG. 63. A, a vitrified 6-inch tile with angle for connection for 4-inch 

 lateral. T, section of 6-inch vitrified tile with T for 4-inch connec- 

 tion. The other sections are of common tile. 



ciently large. A small hammer is much to be preferred 

 to a larger one in this work. The larger the hammer, the 

 greater the danger of cracking the tile from the jarring. 

 With the smaller sizes of tile, the section should be held 

 in one hand while the opening is being made with the 

 hammer. (See Figs. 59, 60, and 61.) 

 201. Designating the sub-mains and laterals in the 



