1909] on the Americans and the Panama Canal. 697 



canal, is really immaterial. Both ways are good. One is much more 

 extravagant in time than the other, that is all. Taking all things 

 into consideration, I think the Americans are right in selecting the 

 cheaper and quicker way of opening a waterway between the two 

 oceans, the lock canal. The Americans need a canal from the Atlantic 

 to the Pacific now, and they cannot wait. There is no reason at all 

 why a lock canal, however good and expensive, should not gradually 

 be transformed, by dredging in the wet, into a sea-level canal. It 

 would not interfere much with navigation, and it would certainly 

 simplify matters in the end. 



I am not at all anxious about the dam giving way in the imme- 

 diate future, but I am curious to see whether the calculations regarding 

 the filling of the lake come true, and whether the porosity and per- 

 meability of the lake-sides will not perhaps present unexpected 

 surprises. 



As will be seen by the diagram illustrating this paper, showing 

 the proposed Gatun Dam in its maximum section, the central portion 

 of the dam will consist of hydraulic fill, with a padding of cheap filling 

 between the slope of the central hydraulic filling and the surface rock- 

 fill. Rock-fill of a cheap description, but quite good enough for its 

 purpose, will be used on the outer face of the dam, but not so on the 

 water side of the dam, which will be protected by a 10-foot thickness, 

 all along the face and summit, of selected rock from Bas Obispo. 

 The rock piles forming each toe of the dam will l)e constructed of 

 selected rock-fill. 



In the company of Major Gaillard, the engineer in charge of the 

 central division, and also alone, I visited several times the Culebra Cut. 



The cut is 9 miles long across the highest par': of the Continental 

 Divide. Its width at the bottom is 800 feet. The lowest depth above 

 mean sea-level is 40 feet. It is here that the French began their work 

 in 1881, and continued it under the new French company until 1904, 

 when the Americans took over and continued the work with the 

 French equipment. The French had done a great deal of work there. 

 They had excavated some 50,361,000 cubic yards of material. 



Witli the arrival of powerful steam shovels and improved equip- 

 ment, the progress made in that portion of the canal by the Americans 

 has been amazing. In 1908, 13,917,433 cubic yards were excavated, 

 and in the first four months of 1909, 5,147,944 cubic yards were 

 removed. 



This extraordinary progress is not altogether due to the improved 

 and more plentiful machinery, but also to the nature of the rock, 

 which is more readily extracted than the slippery clay which formed 

 the upper strata of the Culebra Mount when the excavation first 

 began. M. Bunau-Yarilla was telling me most graphically of the 

 a,nxious efforts which had been made by the French under him in 

 endeavouring to pierce the mass of soft slippery soil until the solid 

 core could be reached where railway tracks could be established on 



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