FORMS OF CANALS. 



243 



the canal. In carrying a canal around the spur of a hill, 

 the earth excavated should be made to increase the width 

 of the bank, as shown in fig. 125, in which the dotted 

 line marks the excavation and the removed earth. The 

 moved earth will adhere more closely to the old surface 



Fig. 124. FORM OF A DEEP CANAL. 



if that is loosened with the pick, so as to secure an inter 

 mixture of the new earth with the old. Where the hill 

 side is of loose earth, it may be necessary to protect it by 

 stonework, laid up as seen in fig. 126. Where a curve is 

 made upon a hillside, it must not be forgotten that the 



Fig. 125. CANAL AROUND A HILL. 



stream impinges upon the bank at every point of the out 

 ward curve. Sometimes, therefore, the stone-work will 

 need to be laid up upon the outer side, as the proper 

 place for it is where the water will wear the most. 

 Protection of some kind will be needed at those points. 

 This may be given by driving stakes and wattling 

 brush among the stakes, with the buts pointing down 

 stream, or by increasing the slope of the banks on 



