Page:Popular Science Monthly Volume 32.djvu/163

Rh establish its impracticability. The advocates of San Blas counted upon further advances in the tunneling art, just as De Lesseps has counted upon and witnessed like advances in the art of constructing and operating the excavator and the dredge.

We have considered the way in which inventions expedited the cutting of the two greatest engineering works, probably, ever built to promote communication by land; the two greatest to promote communication by water remain to be considered. The Alpine invention, the air-pressure engine, was not used upon the Suez Canal, nor has it been at Panama. The special kinds of work to which it is adapted are tunneling and mining. There could be no question of a tunnel at Suez. On the other hand, in the plan for a sea-level canal at Panama submitted to the Paris Congress, two solutions were presented. The Cordilleras were to be pierced either by a tunnel or open cut. Tunnels of four or five different lengths were proposed, and calculations submitted; but the congress came to no decision on this point. Had the tunnel plan been adopted, the tunnel would have been excavated by the Alpine method, but subsequently the open-cut plan was adopted, and hand or steam drills instead of air-pressure drills have been employed. Nitro-glycerine, however, which had been substituted for powder during. the work at St. Gothard, is largely used.

In considering the two canal enterprises of De Lesseps, we begin with the one completed. As has been said, when, through the intervention of the British and Turkish Governments, the Suez Company had to abandon forced labor, not a little injury was inflicted upon the work. The damage was obviated in part by the indemnity paid by the Egyptian Government, thirty-eight million francs, and in part by the inventions of French engineers. In fact, the company proved to be the vainer. The immense dredges which took such an active part in the rest of the work were contrivances of this period. As to the power and capacity of these machines, we can hardly do better than quote the British historian of the canal, Percy Fitzgerald. After observing, vol. i, page 202, that the chief contractors, Borel and Lavalley ("men of extraordinary energy and fertility of resource"), came to the task under every disadvantage, and had to establish their workshops and machinery in the desert, he continues:

"They saw at once that the new difficulties as to procuring labor and the limited time allowed by the contract could only be overcome by the aid of machinery of the most daring and novel kind. They accordingly devised those extraordinary dredges which have been the admiration of engineers. . . . No one," he adds, "who has seen an ordinary dredge at its slow work in an English river could have an idea of the bold fashion in which the principle was now applied."

And he thus refers to the general capacity of foreign engineers: