Page:Popular Science Monthly Volume 8.djvu/687

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the desert. If there ever was a great river flowing into it, its bed has been obliterated by the shifting sands.

At a later date Tritonis appears as three connected lakes, called, respectively, Libyca, Pallas, and Tritonis, which some recognize in the Shotts Melrir, El-Rharsa, and El-Jerid, It is probable that the mouth became gradually blocked up with sand, and the lake, no longer receiving sufficient water from the Mediterranean to supply the waste from evaporation, separated into several smaller seas, which, by continued desiccation, became transformed at last into their present condition. When this took place can only be conjectured, but it was probably in the early centuries of the Christian era. The Arabs preserve the tradition that Shott Es-Selam was a lake at the time of the Mussulman conquest. They also aver that the lake bed has not been covered with water during the past hundred years.

Although it has long been known that this desert basin was lower than the Mediterranean, nothing was positively settled in regard to it until 1873, when Captain Roudaire, a staff officer of the French army in Algeria, ascertained the altitude of Biskra, and by a series of levelings from that point proved that the western extremity of Shott Melrir was twenty-seven metres, or nearly eighty-nine feet, below the level of the sea. The publication of his investigations and an exhaustive discussion of the probabilities of success in reopening the ancient lake, in the Revue des Deux Mondes (May, 1874), aroused interest in the project in hope not only of reclaiming the country, but also of opening a commercial avenue to Southern Algeria. The French have long sought to deflect the caravan trade of Middle Africa, which is now mostly monopolized by Morocco and Tripoli, to Algiers, but in vain, the increase in prices to be obtained in Algiers not being sufficient to compensate for the increase in distance. But with an inland sea the circumstances would be changed. The country around it would resume its ancient character of a littoral province, and the caravan routes of the Sahara would converge toward a port established on its southern border, whence the gold dust, ivory, gums, and ostrich feathers of Soodan would be shipped directly to Europe to the detriment of the Mohammedan markets. Tougourt, too, the French military post in southern Algeria, now distant nearly two hundred and fifty miles from the port where its provisions are landed, would then be only about forty miles from the sea.

Captain Roudaire discusses also the probable climatic changes which would ensue from reopening the Bay of Triton. He argues that the northwest winds, which prevail in summer, would be less violent than now, and the southwest winds, which blow during the remainder of the season, would be charged with vapor and cause a greater fall of rain in Algeria, Sicily, and South Italy, without materially modifying the climate. This increased rainfall would restore the land to its ancient fertility, and the region of the shotts would