Culebra Cut, from West Bank, showing Shovels at Work.
The pessimists have of course been busy with these landslides in the "Cut." They predicted that the canal along this section would always be exposed to danger from that source. But here, too, every precaution has been taken. The engineers have given a much lower slope to the sides of the canal, which is therefore wider at the top than had been originally planned. The slopes will also be sown with creeping grasses and other plants, which will bind down the surface soil. When the forty-five feet of water are in the canal, the bottom will be held down by the weight, and the bulgings no longer take place. Moreover, any earth that, in spite of all precautions, still manages to slide into the canal should be easily dealt with by the big 20-inch suction dredges, which can be brought up through the locks and set to work. So we need not trouble much about the stability of things along this nine-mile section through the Culebra Mountains.
Here as elsewhere it is possible to give only a very general idea of the difficulties which were encountered and overcome in the course of construction. The drainage of the "Cut" during the work was in itself a heavy and important task. It was necessary to keep out the water of the surrounding country and to rid the excavated area of water collecting in it. A system of diversion channels, carrying off the Obispo River and its tributaries, effected the first object, and the second problem was solved by gravity drains and pumps. On the whole, this mighty trench through the isthmian hills is not only the biggest thing to the credit of a nation which delights in bigness, but the greatest achievement of its kind the world has ever seen.
FOOTNOTE:
[16] "South America," p. 26.
CHAPTER XIII.
THE LOCKS.
The Panama Canal belongs to the "age of concrete." All other vast works of construction, such as the Pyramids of antiquity and the Assouan Dam of to-day, have been built of live natural rock. At Panama everything—locks, wharves, piers, breakwaters—has been constructed of concrete. The Americans have not only built these incomparable piles of masonry; they have manufactured the material out of which they are built. This circumstance makes the rapid completion of the canal all the more wonderful. Not less than four and a half million cubic yards of artificial stone have been produced for the built portions of the canal and its accessories. This amount of concrete, we are informed, would make an ordinary sidewalk nine feet wide by six inches thick reaching more than twice round the earth.