1909] on the Americans and the Panama Canal. 693 



I think that M. Bunau-Yarilla's method of disintegrating rock 

 under water by mechanical concussion, instead of by the old mode of 

 dynamite mines which shattered the rock into small fragments, is 

 most excellent, and should certainly be cheaper than excavating in 

 the dry. Transport of materials by water is undoubtedly less ex- 

 pensive than over land. Everybody will, I think, fully agree with 

 the American engineers and with M. Bunau-Varilla that it would be 

 folly to contemplate excavation in the dry of a sea-level channel 

 across the Isthmus of Panama. It would take from forty to sixty 

 years at least to complete it, and it would be unwise to prophesy its 

 eventual cost. With the powerful dredges which are to-day built, 

 such a thing is rendered more possible. There is no reason why, as 

 M. Bunau-Varilla says, dredges which now float in harbours and 

 rivers should not float and operate in an artificial lake. M. Bunau- 

 Varilla's plan, which is excellent, provides for provisional locks and 

 a steel and concrete dam for the Chagres. Where the river would 

 thus form falls, electricity to be used as a motive power could be 

 generated at little cost. A lake 200 feet above sea-level would be 

 formed, providing in itself a suitable dump for the waste. This 

 would prove economical as well as simple. 



M. Bunau-Varilla is a man whose words cannot be neglected. He 

 has valiantly defended the certainly ideal form of canal, the open, 

 wide, deep passage between the two oceans entirely freed of any 

 artificial structures such as locks and dams — " The Straits of 

 Panama," as he rightly calls them, in contradistinction of a tide- 

 locked " Sea-level Canal." 



Now let us see what the American engineers are doing. 



Mr. C. M. Saville, the well-known xlmerican engineer, made for 

 the Government an interesting investigation of the foundations of 

 the dam and spillway, especially with the object of searching whether 

 a permeable connection existed through the alluvial deposits in the 

 relatively narrow valley across which the dam is now being con- 

 structed. The dam will rise between swamp areas to the north and 

 the broad flats of the (xatuncillo and Chagres River to the south. 



The alluvial deposits in the gorges of the Chagres River, across 

 which the dam will be built, are composed for a depth not surpassing 

 80 feet almost entirely of fine sand. Under this for some 100 feet 

 borings show a thick deposit of blue clay with sand and shells. 

 Below this and directly overlying the rock is a conglomerate deposit 

 of stones, angular gravels and sand, solidified and finely cemented 

 into a solid mass with fiuely divided clays and silts, which are 

 believed to be the product of decomposition of the immediate rock 

 surface. This layer is waterproof and non- water-bearing, having 

 been rendered so by the leaching and filling of the overlying de- 

 posits. According to excavations and borings, no continuous layer 

 of loose sand or gravel has been found, and no deposit has been 

 encountered that appears sufficiently extensive and permeable to 



