492 



Popular Science Monthly 



rin Press Association 



The "Cascadas" is the largest all-steel dredge in the world. It scoops up fifteen wagon-loads 

 of material at a time, and has disposed of as many as seventeen thousand wagon-loads of 



earth and rocks in a single day 



Digging Away the Slides at Panama 



THE whole Panama Canal zone may 

 be imagined as an aggregation of 

 slopes of hard material upon which 

 softer materials rest. In cutting the 

 canal the equilibrium maintained be- 

 tween the upper and the lower strata 

 was disturbed. As a result the overlying 

 material tobogganed down into the cut 

 which constitutes the canal, upon the 

 inclined under material. Nothing can 

 stop the movement now in progress until 

 the angle of repose is attained, and this 



can be reached only by removing the 

 excess amount of material. Col. Goeth- 

 als states that seven million cubic yards 

 must be remo\ed before the slides are 

 entirely stopped, and that this is at best 

 only a guess. "It must not be inferred," 

 says Col. Goethals, "that the canal will 

 be closed until this amount is dredged ; 

 on the contrary, it is the intention to 

 pass ships as soon as a channel is secured 

 through the remaining six hundred feet, 

 and there are reasonable grounds for as- 



