THE TYPE OF TEE PANAMA CANAL 435 



then at his command, the president reached the conclusion that a canal 

 with locks would best fulfil all requirements, and says in transmitting 

 the board report to the Congress : 



In my judgment a lock canal as herein recommended is advisable. If the 

 Congress directs that a sea-level canal be constructed, its direction will of 

 course be carried out. Otherwise the canal will be built on substantially the 

 plan outlined in the accompanying papers, such changes being made, of course, 

 as may be found necessary, including possibly the change recommended by the 

 Secretary of War as to the site of the dam on the Pacific side. 



When the matter was before the senate committee on inter-oceanic 

 canals, another opportunity was provided for the expression of views 

 by experts. At these hearings. Professor Burr said that he was as 

 strongly in favor of the sea-level canal as he ever had been. 



The more I reflect upon it, the more it seems to me that that plan is the 

 one which the United States Government should adopt. 



In discussing the Gatun dam, which is a feature of the lock-canal 

 project as adopted, he says: 



It is proposed to build this dam by simply clearing off the surface material 

 and then spreading the earth, suitably selected from the canal excavation, in 

 layers, and so building it up to a height of 135 feet, making its base something 

 like half a mile wide.^ In my judgment, that is a dangerous experiment on a 

 colossal scale, which this government is not justified in undertaking. 



Continuing, Professor Burr states that he has no objection to earth 

 dams under suitable conditions if properly designed and founded. 

 Anything like a flow of water through the permeable material under the 

 dam should be prevented. No suitable means for accomplishing this 

 are provided in this design. He indicates measures that are ordinarily 

 taken to check the flow of water under a dam, and instances several 

 failures of earth dams. In speaking of the dams near LaBoca resting 

 against Sosa Hill, the construction of which was subsequently under- 

 taken, but owing to the yielding, unstable character of the marsh lands 

 on which they were to rest, have been abandoned. Professor Burr says : 



The dams on the Pacific side are smaller, and the risks, perhaps, may be 

 of less magnitude; but they are of the same character, and there is the same 

 objection to them, in my opinion. This dam between LaBoca and the high 

 ground opposite would be founded largely upon the most slippery kind of mud. 

 Any one who has been there and has seen the bottom of the Rio Grande estuary 

 exposed at low tide, I think will agree with me that it is a very lubricating 

 material; and if you were to put a bank of earth on it, even if it were half a 

 mile thick, I think it would be in great danger of being pushed out bodily. 



In speaking of the operation of locks, he calls attention to the fact 

 that the experience at the lock at St. Mary's Falls is not a safe guide 

 for reaching conclusions regarding the safety of six such locks as will 

 be required for the Panama Canal. Their lift is 50 per cent, greater, 



'As now contemplated, the dam is to be constructed by the hydraulic fill 

 method. 



