But though the continuous “Bahr bela ma” channel of the old cartographers has been shown to be purely imaginary, and has in consequence disappeared from our modern maps, the belief that an old dry river-bed _may_ exist _somewhere_ in the Libyan Desert has apparently persisted in many minds even to our own day. Only a few years ago I was called upon by the Government to discuss a suggestion, made in all seriousness by a person of considerable eminence, that the Nile, or a branch of it, must at one time have followed a course from somewhere near Dongola through some of the Egyptian oases to the Mediterranean; and that by tracing out the old channel, and deepening it artificially where necessary, a part of the river might be taken off along this path and its water utilized to irrigate the desert country on either side of it. To the few scientific travellers who have journeyed extensively in the Libyan Desert, it will doubtless appear incredible that such a suggestion as this could be seriously made. But old traditions concerning the geography of little-known regions die hard, and this particular one has probably been fostered by the circumstance that on most small-scale maps the oasis-depressions have been shown without any precise indication of the altitude of the intervening ground, as well as by the speculations of geologists as to the existence of a river in the region in past geological ages. Blanckenhorn, for instance, published in 1902 a series of small-scale maps depicting the course of a hypothetical river, the “Libyan Ur-Nile,” running northwards through the desert in the Eocene and Oligocene periods, and ceasing to exist in the Pliocene.[9]