Page:Popular Science Monthly Volume 16.djvu/407

 the highest overflow of the water; but this line will, doubtless, be too tortuous to enable one to follow it correctly, or to be always above it; one should, in order to obtain reasonably straight lines, or curves not too sharp, bring the canal partially to the Thalweg of the valley; it will therefore be necessary at several places to change the bed of the Chagres, the bends of which multiplied would encroach upon the route of the canal. But the land, coming from this partial changing of the line, as well as that which would come from digging out the canal itself, turned up to a moderate height, quite equal to the corresponding height of the embankment of the railroad, would make a dike which the water of the Chagres could not pass over. At the place where the line of the canal will necessarily cross the bed of the Chagres to fall into the Bay of Limon, the Chagres will be turned from its course to allow the canal to pass at its left.

On the other bank the river Trinidad, a left tributary of the Chagres, would be, on the contrary, kept on the right side of the canal, and, by means of an easy change of its course, would flow in the actual bed of the Chagres to that very river to the north of Limon Bay, taking therefore, to become itself a river, the river of which it was only a tributary. What, then, would be the expense of this radical change? We have not at hand all the details necessary to calculate it; but, allowing an expense of fifty million francs for this work, we think it would amply be provided for.

But, should this plan not prove successful, there is another suggested by Messrs. Wyse and Reclus, which is also perfectly feasible, and the expense of which can be more closely calculated. This is, to build over Cruces an immense reservoir, capable of holding more than six hundred cubic metres of water—that is to say, more than the volume of water which could possibly be formed during several days of the greatest overflows of the Chagres, which, we are told, amount to occasionally, but for a very short time, twelve hundred cubic metres a second. This work would cost twenty-five million francs, but it would free us from all apprehension of the devastation occasioned by this river, which at times becomes a torrent, for the letting it off under the reservoir would be done gradually and without danger into a bed arranged beforehand, leaving the canal always on the left. For opening this bed, which would not at all be the same one as that of the Chagres, for straightening it at different places, and for doing the same for the river Trinidad, seventeen million francs should amply suffice.

Freed, therefore, from all fear, nothing more remains but to regulate, I can say even to a few centimetres, the height of the water in the ship-canal; and then comes in the second change that we suggest to the plan of Messrs. Wyse and Reclus, which is, merely to provide against the occasionally very rapid currents which would come from the great rise and fall of the tide on the Pacific, which sometimes amount to six metres. This can easily be managed by a tide-barrier