LAWN BEAUTIFICATION 277 



The general impression is that cracks should 

 be left, and sand put in the cracks. The real way 

 is to surround the joints with clay; then they are 

 permanent. The worst thing to do is to put sand 

 or gravel or straw about the cracks. A tile four 

 feet deep will drain twice as wide an area as 

 a tile two feet deep. About four feet is the 

 best general depth where a lower outlet is at 

 hand. 



The strength of the entire system depends 

 upon the weakest section. Therefore it is neces- 

 sary in laying the tile to examine carefully each 

 piece, and to see that they are well burned, but 

 not sufficiently to make them impervious. The 

 system must be laid upon the proper grade, for 

 if the line sags, sediment will collect and retard 

 the flow of water. 



It is best to make a silt basin at the point 

 where the branching tiles unite. This is formed 

 by digging down a foot or two, and bricking or 

 cementing up a barrellike receptacle, the en- 

 trance pipe from the main system being a little 

 lower than the exit pipe, so that the silt may 

 settle. 



In the twenty-five years since the tile system 

 was laid at Santa Rosa, the tile itself has never 

 been exposed or in any way touched or examined. 

 It continues to perform its function perfectly. 



