GENERAL METHODS 145 



over it, in order to make a division, as described 

 earlier in the chapter. You are now ready to 

 start a new section. Raise the end of the oil-cloth, 

 tacking it up as before. Carry the strips of can- 

 vas back and forth across the opening until a 

 height of a foot or so is reached. Then drop 

 the oil-cloth, put in the concrete, and proceed as 

 before. 



When the filling is completed it must be allowed 

 to stand for several hours, the exact time depend- 

 ing upon the weather, the richness and wetness of 

 the mixture, and the size of the filling. If possi- 

 ble, put in the filling in the morning and inspect it 

 occasionally during the afternoon. As soon as 

 it becomes resistant to the fingers and a little force 

 is required to cut into it with a trowel, take off 

 the canvas strips and the oil-cloth. Then chip 

 or scrape the filling off down to the proper level 

 and contour, starting with the spots which require 

 the most cutting away. If a pebble here and 

 there runs farther back into the concrete than it 

 is desired to cut, simply pull it out and leave a 

 hole there. If the surface resulting from this 

 process is not sufficiently smooth, dampen the sur- 

 face thoroughly and cover it with a thin stucco of 

 wet mortar made of one part cement and two 

 parts sand. The stucco should be as shallow as 

 possible; indeed, it is best simply to fill up the 

 deeper holes made by knocking out stones from 



