Mr. Horneman, in his way westward from Cairo, passed the Natron Valley, at the distance of about 40 G. miles from Cairo; and, by circumstances, not more than 9 or 10 from the extreme southern part seen by General Andreossy. At the distance of about 8 miles from the Natron Valley he _descended_, and came to what he calls the foot of a _sand hill_; but it being _dark_, he could not form any idea of the place itself, or of the adjacent country: he however observes, that it will be proper for future travellers to look in this place, for the _course_ of the _Bahr-bela-ma_: doubtless, because he found a deep and capacious hollow; but concerning which, he gives no farther intimation. Adverting, therefore, to the description of General Andreossy, I regard the _sand hill_ rather as the _ridge_ that separates the two valleys or hollows, than as the thing Mr. Horneman took it for. He says, that they _descended_ the sand hill, in _indescribable_ disorder;[28] which seems to imply a _long_, as well as a _steep_ descent: and, leaving the place, before it was light enough to form a judgment of the nature of it, he only directs the attention of others to it: surely, because it was a hollow tract. It may be allowed, therefore, that the Bahr-bela-ma and Natron Valleys extend 40 or more G. miles, pointing northward to the Lake Mareotis, or to the Gulf of the Arabs; and on the other hand, towards the quarter of the lake of Kairun; from whence they seem to be less than 30 miles distant. The four hours of travelling, between the station at the Natron Valley, and the foot of the sand hill, does not ill agree with the ground. The breadth of the Natron Valley, 6½ G. miles, is, reckoning the ascent on the west, equal to 3¼ hours travelling; and General Andreossy says, that he was 40 minutes in descending the slope, to the bottom of the Bahr-bela-ma. (Mem. p. 240.) Here then we have made out nearly the four hours: besides, it is not certain that the hollows may not have been crossed obliquely, by Mr. Horneman. It appears that M. D’Anville believed the existence of, and has expressed on his map of Egypt, a hollow or valley, extending the whole way from the lake Kairun, to the neighbourhood of the Gulf of the Arabs. The French, it seems, have never had an opportunity of determining the questions; which appears extraordinary. I shall now proceed to the description of another valley, which may possibly be a branch of the Bahr-bela-ma. _Valley of Mogara._