4.7 o The National Geographic Magazine 



white man can work without expense 

 of physical energy, where he can work 

 seated, so to speak, protected from the 

 sun, protected from the rain ; second, 

 because it is the only instrument where 

 the colored man remains under imme- 

 diate supervision, where he is attached 

 to tasks always the same and under the 

 eye of the overseer ; third, because it is 

 the instrument least liable to suffer from 

 an error or an accident. If a little slide 

 comes it withdraws and is not buried, 

 as an excavator or a steam shovel. If 

 the attack of the ground is too hard, it 

 simply stops instead of risking to lose 

 its equilibrium ; it does not derail, ' ' &c. 



DREDGING WAS PREFERRED TO OPEN 

 AIR ROCK EXCAVATION DURING THE 

 OLD PANAMA COMPANY WORK, WITH 

 MUCH LESS POWERFUL DREDGES 

 THAN ARE NOW USED 



"Anybody who has worked on the 

 Isthmus with the two systems cannot 

 but be struck with the enormous supe- 

 riority of the dredge. It is so apparent, 

 so obvious, that I did not hesitate at 

 Culebra, as soon as the conditions be- 

 came compatible with a dredging plant, 

 to endeavor to substitute the work of 

 the dredge to that of dry digging, and 

 this in a hard clay that necessitated the 

 employment of explosives for the work 

 of excavating machines. 



"Unfortunately, the plant was just 

 in action when the collapse of the old 

 company came ; but however small has 

 been its period of activity, perhaps a 

 couple of months, the result completely 

 confirmed my expectations and filled my 

 hopes. Unfortunately for the canal, 

 the inevitable and blind reaction which 

 followed such a disaster as that of the 

 Panama enterprise put into suspicion 

 the clearest results obtained. I con- 

 sider that it has been, among others, one 

 of the most fatal mistakes of the New 

 Panama Canal Company not to continue 

 in the same line of effort. 



" What they have done in the Culebra 

 Cut would have been infinitely cheaper 



and quicker done if they had followed 

 my last plans and not simply continued 

 dry excavations, which I had put in 

 action for a much longer period than 

 the wet process. 



"Since that time no more dredging^ 

 has been done on the Isthmus, and there- 

 fore the truth has not been able to be- 

 again found and recognized. 



' ' It can be stated with certainty from 

 practical experience, such as the records 

 of the Suez Canal may show, that under 

 the very propitious conditions in which 

 the excavation will be made on the 

 Isthmus, without currents or without 

 variation of water level, it can be made 

 at a cost less than $i per cubic yard, 

 including repairs and depreciation of 

 machinery. It can be equally stated 

 from the same Suez Canal records that 

 m their rock may be extracted and dumped, 

 including repairs and amortization of 

 machinery, at a cost not reaching 75,. 

 cents a cubic yard. As for the hard 

 clay, even with the light blasting it re- 

 quires, the price ought to be kept be- 

 low 30 cents a cubic yard with ordi- 

 nary dredging and much reduced with 

 electrical appliances, even including 12 

 cents for the amortization of the locks- 

 ascending to Lake Gamboa. The ex- 

 cavation of hard clay may be brought 

 still lower with the new dredging ap- 

 paratus resulting from the combination, 

 of cutters and suction pumps, but this- 

 is an eventuality of the future, and,, 

 though already resting on large experi- 

 ments in Canada, it is not sufficiently 

 proved adaptable to the isthmian ground 

 to base reasonable and conservative esti- 

 mates on, such as I give today. 



' ' I have prepared the way for the em- 

 ployment of electricity in the working; 

 of the dredges, and I had built in Hol- 

 land by Smulders an electric- driven, 

 dredge in 1895, according to special 

 plans which I drew, and which was, so 

 far as I know, the first electric dredge 

 ever employed in public works. The- 

 results I obtained on the River Elsa, in, 



