Smithsonian Report, 1947. Ho 



1. Test drilling and blasting at unprecedented depths of 135 feet below water 

 surface are being carried out from a barge plant in the approach to the Third 

 Locks Cut on the Atlantic side. 



2. Tide-control structures simulated in the half-mile-long hydraulic model of a 

 sea-level canal built to the alignment of the existing canal. To the left is the 

 tide lock. The man is standing over the navigable pass gate, and to his left is 

 the water-control structure. During tests the model is covered with canvas, 

 as at the right, to shield it fi-om ihe wind. 



