The idea was that in Palaeolithic days, contemporary with the Glacial Age of Northern Europe and America, the climate of Egypt was entirely different from that of later times and of to-day. Instead of dry desert, the mountain plateaus bordering the Nile valley were supposed to have been then covered with forest, through which flowed countless streams to feed the river below. It was suggested that remains of these streams were to be seen in the side ravines, or wadis, of the Nile valley, which run up from the low desert on the river level into the hills on either hand. These wadis undoubtedly show extensive traces of strong water action; they curve and twist as the streams found their easiest way to the level through the softer strata, they are heaped up with great water-worn boulders, they are hollowed out where waterfalls once fell. They have the appearance of dry watercourses, exactly what any mountain burns would be were the water-supply suddenly cut off for ever, the climate altered from rainy to eternal sun-glare, and every plant and tree blasted, never to grow again. Acting on the supposition that this idea was a correct one, most observers have concluded that the climate of Egypt in remote periods was very different from the dry, rainless one now obtaining. To provide the water for the wadi streams, heavy rainfall and forests are desiderated. They were easily supplied, on the hypothesis. Forests clothed the mountain plateaus, heavy rains fell, and the water rushed down to the Nile, carving out the great watercourses which remain to this day, bearing testimony to the truth. And the flints, which the Palaeolithic inhabitants of the plateau-forests made and used, still lie on the now treeless and sun-baked desert surface. [Illustration: 007.jpg THE BED OF AN ANCIENT WATERCOURSE IN THE WADIYÊN, THEBES.] This is certainly a very weak conclusion. In fact, it seriously damages the whole argument, the water-courses to the contrary notwithstanding. The palæoliths are there. They can be picked up by any visitor. There they lie, great flints of the Drift types, just like those found in the gravel-beds of England and Belgium, on the desert surface where they were made. Undoubtedly where they were made, for the places where they lie are the actual ancient flint workshops, where the flints were chipped. Everywhere around are innumerable flint chips and perfect weapons, burnt black and patinated by ages of sunlight. We are taking one particular spot in the hills of Western Thebes as an example, but there are plenty of others, such as the Wadi esh-Shêkh on the right bank of the Nile opposite Maghagha, whence Mr. H. Seton-Karr has brought back specimens of flint tools of all ages from the Palaeolithic to the Neolithic periods.