July 20, 1906.] 



SCIENCE. 



77 



tend that the only suitable canal across the 

 Isthmus of Panama, commensurate with 

 the great interests involved, especially those 

 of the United States, is one which will per- 

 mit the safest and freest passage of traffic. 

 It is contended that there should be prac- 

 tically no obstruction to a free transit 

 across the isthmus ; that any canal now con- 

 structed should accommodate conveniently 

 and freely the greatest ships afloat, and be 

 of such a character as to admit of the 

 easiest and most economical enlargement in 

 the future if it should ever be required, and 

 that the sea-level plan only fulfills all these 

 fundamental requisites. Although there 

 would be a tidal lock at the Panama end of 

 the canal, inasmuch as the range of neap 

 tides may not esceed seven or eight feet, 

 the gates of that lock would be wide open 

 at least one half of the time. There are 

 hydraulic engineers of repute, who even 

 believe that this lock would not be neces- 

 sary. The majority of the board further 

 contends that the operation of three locks in 

 series would be a source of grave danger, 

 indeed, a continual menace to the safety of 

 the large ships passing them. Serious acci- 

 dents caused by ships ramming the gates 

 of both the Manchester Canal in England 

 and at Sault Ste. Marie, Mich., show that it 

 would be possible, and even probable, that 

 some ship approaching the upper of these 

 gates might ram them out of position and 

 plunge down through the entire series. 



Although the minority claim an annual 

 capacity of sixty to seventy million tons 

 of traffic for its lock plan, this claim has 

 been strongly contested, and evidence 

 brought out before the senate committee 

 indicated that it would be more reasonable 

 to place the maximum annual capacity at 

 one half that amount or less. 



Again the safety or stability of the earth 

 dams, on which the very existence of the 

 minority plan is based, has been most seri- 



ously questioned. A considerable number 

 of borings made into the material on which 

 it is proposed to place the Gatun dam show 

 that the maximum depth of that material 

 is not less than 258 feet ; that it is largely 

 sandy, and in some places gravelly and 

 freely water bearing, i. e., permeable at 

 various depths from thirty-two feet below 

 the surface down to nearly two hundred 

 and fifty. These conditions, it is alleged, 

 might lead to dangerous percolation un- 

 der the dam, and so bring its stability into 

 grave question. Somewhat similar criti- 

 cisms have been made regarding the earth 

 dam across the tidal estuary of the Rio 

 Grande. 



Although the capacity of the sea-level 

 canal has been also criticized or questioned, 

 that capacity was shown to be practically 

 unlimited. Although most serious conges- 

 tions of ships arriving in groups or fieets 

 at either end of the lock canal might lead 

 to long delays in some cases with a lock 

 canal, it was shown that no such congestion 

 could occur with the sea-level canal, even 

 at the Panama end, for the half of any 

 tidal period would permit any group of 

 ships to pass into the canal while the gates 

 were open. 



The one hundred and fifty feet bottom 

 width of the sea-level plan exceeds the 

 width of even the turning out or passing 

 places in the Suez Canal. In other words, 

 the Panama sea-level canal would be a con- 

 tinuous passing place throughout its entire 

 line. The total curvature of the sea-level 

 plan was also shown to be less than that of 

 the lock plan, and but little different from 

 the total curvature of the Suez Canal. 

 The lock plan with the large terminal lakes 

 has the further serious disadvantage of 

 possessing a minimum adaptability to 

 transformation to a sea-level canal in the 

 future. While this transformation is a 

 possibility, the great difficulties attending 

 it, and the excessive cost of that trans- 



