158 THE POPULAR SCIENCE MONTHLY. 



The connection is so close between the consistency of the strata 

 and the slope of the cutting, that the following as to this point will be 

 of interest. The director-general continued : 



Well, these borings, made in large numbers at Culebra, showed us that we 

 had to excavate a rock, semi-hard, schistous in quality, having nearly horizontal 

 strata, and that the earth was dry. The result is, that one could not desire better 

 earth for a -work of such an exceptional character. We shall be obliged, mani- 

 festly, to be very prudent. Accordingly, at the top we have opened the cutting, 

 as if the slope was to be a gentle one. We remove the clayey part which, under 

 the action of water, can be brought to the consistency of paste or mud. Here 

 we have made a very ample opening. But in proportion as we reach clear rock, 

 we make the prism narrower, so as to comprise the cubic contents strictly neces- 

 sary, with the purpose to make the slope more gradual should experience 

 require it. 



The bringing together by an undertaking such as Panama of con- 

 tractors of divers nationalities, naturally leads to the use of various 

 machines, and it remains to be seen what advantage is to be derived 

 from the sort of rivalry thus established. Here the Panama work may 

 be said to possess an advantage over Suez. The latter was almost ex- 

 clusively in the hands of French engineers, and was carried through 

 by French contractors and inventors. A single Englishman, Ayton, 

 contracted for a considerable part of the work, but he became bank- 

 rupt owing to the withdrawal of forced labor, and the French w-ere 

 obliged to assume his portion.* In the case of Panama, contractors 

 of several nationalties have been employed — French, English, Dutch, 

 Swedes, Swiss, Italians, Americans, and Colombians. The "Canal Bul- 

 letin " for February 15, 1885, contains a table of contracts, arranged 

 according to nationality, entered into at the time. 



After treating of the American use of the diamond-drill, the di- 

 rector-general proceeded to sjieak of some of the other machines 

 employed. f He said : 



The excavation is effected in different ways. We are very eclectic at Pana- 

 ma. We reject no system, no method, and as the earth varies at every step, as 

 the works at one point do not resemble those at another, we can try different 

 ways. At certain places we have mellow earth, which is generally composed, in 

 the valleys, of clay mixed with a feldspathic sand. In such places we can make 

 the attack by mechanical processes. We employ excavators. 



There are two sorts of excavators, the French and American. The Ameri- 

 can excavators are very ingenious, and in mellow soil they give satisfactory re- 

 sults. The French excavators are of a type already tested iu many places. In 

 clayey and rather adhesive earth they seem preferable. Accordingly, the 

 American papers, knowing, not that we had declared as much, but that facts had 



* Fitzgerald's "Suez Canal," vol. 1, p. 200. 



f The diamond-drill has recently been put at Panama to a use other than prospecting. 

 The apparatus of the American Diamond-Drill C'ompany is cniiiloycd to blast rocks 

 under water. Dynamite is the explosive used, and the rock is so thoroughly shattered 

 that a dredge readily removes it. (See "Canal Bulletin," January 15, 1887.) 



