CONCRETE LINING FOR IRRIGATION CANALS. 



59 



extra expansion and renders the joint more impervious, it adds noth- 

 ing to the bond between the sections. 



Fig. 4.— A broken joint in concrete lining, New York Canal, Boise, Idaho. 



(3) An interlocking device (fig. 3, c), consisting of a 4-inch strip 

 of corrugated iron, was inserted in each joint of the lining of the 

 North Side Twin Falls Canal, Idaho. If the metal strip is thickly 



