AUGUST: FOURTH WEEK 



213 



in your locality. Once done, however, concrete will last 

 practically forever. If concrete is used the wall should be 

 put down at least to the frost-line, and be four inches 

 or more thick above ground. Use more cement in propor- 

 tion to the sand and gravel than for ordinary walls. A 



Cross-section of 10 x 20 lean-to house. 



mixture of i to ij^ parts cement, 2 of sand, and 4 of gravel 

 or broken stone will be right. For the post-and-board con- 

 struction posts are put into the ground every four or five 

 feet apart, and the wall built on the outside. Cedar is the 

 best wood to use for the posts, but chestnut or some other 

 local sort which does not rot quickly will answer the pur- 



