LABORATORY PRACTICE 



239 



That tile 5 be a 6-inch clay tile of a texture similar to 

 that of 4. 



That the nature of tile 6 be determined by the require- 

 ments of the laboratory. 



FIG. 93. Apparatus for studying movement of water through tiles and 

 influence of tile upon ground water. 1, 2, 3, 4, 5, and 6, tile of differ- 

 ent sizes and nature, and explained in detail in Fig. 94 ; W . . . W, 

 water gauge tubes connected with 2-inch tile as explained and 

 shown in Fig. 95. See description, pages 238-239. 



These tile should rest, as is shown in the figure, in a fine 

 sand which fills the tank to the height of 3 feet above the 

 center of the tile. 



Figure 94 shows a tile in cross section and so arranged 

 that water can enter it only through its walls. The legend 

 follows : 



A, Section of tile. 



B, Steel or cast iron plates. 



C, Gaskets. 



