144 PRACTICAL TREE REPAIR 



the opening by the canvas strips. Inspect the in- 

 side of the eighteen-inch wall or dam thus pro- 

 duced, making sure that It is firm and tight to the 

 edges of the opening. If it appears possible that 

 the mortar will escape along those edges, a rag or 



Two stages in the process of filling a basal cavity with concrete 

 by the wet method 



some waste or a bit of clay can be used to plug 

 up the loose places. Now shovel in the concrete, 

 spreading and tamping it at the same time. See 

 that it flows into every corner and that no part of 

 it escapes the tamp. When the concrete has 

 reached the top of the dam, give it a final tamp- 

 ing, level it off, and spread a sheet of newspaper 



