=Gebel Abu Hamamid= is a great ridge of hard greenish schists towering above the surrounding mountains to a height of 1,747 metres above sea. Its crest is broken into a number of separate summits, which appear from most aspects of almost a sugar loaf form; the beacon is on the most northerly and highest of these, its position being latitude 24° 14′ 41″, longitude 34° 47′ 38″. The mountain is best ascended from the Wadi Um Semiuki, a tributary of Huluz, which drains its north-east face. By ascending this wadi till camels could go no higher owing to its increasingly rough and stony floor, I was able to pitch a camp at 865 metres above sea-level and two and a quarter kilometres north-east of the summit, leaving an ascent of 882 metres to be made on foot. The ascent, which occupied four hours, was free from difficulty till within about one hundred metres of the top, but the last portion was extremely steep and was only negotiated with considerable trouble; it represents pretty nearly the limit of possibility in getting instruments up difficult places. Once the top was reached, however, the magnificence of the view obtainable, and the excellence of the point as a station for triangulating the principal peaks among the thousands visible, seemed an ample recompense for the trouble of reaching it. The top of the ridge (_see_ Plate VII, p. 166) is very rough and narrow, only a little over a metre wide, and it is difficult to find a spot near the summit where one can spread one’s blankets for the night with even a slight approach to comfort. The eight nights of enforced bivouacking which I was obliged to spend on the top of Abu Hamamid in February 1906, before I could complete my observations, belong to the least pleasant of my experiences in the desert. A little work only was possible the first day, owing to haze obscuring the more distant peaks. On the second day clouds enveloped us in a wet drizzle, and a bitterly cold north wind blew with great violence; a rude rubble shelter which my men built on the summit, covered with a blanket, was a very poor protection, and I found it better to throw a rubble embankment across a steep gully on the lee side, forming a small level platform where we were sheltered from the biting wind. For the next five days, we were alternately wrapped in clouds or left free under a brilliant blue sky with clouds covering all the surrounding country. It was curious on these days to look over the surface of the clouds, as over a boundless level sea, with only the highest peaks projecting sharp and black above the white surface, and to see the sun rise and set exactly as though one were on the ocean. Then at last the clouds began to disappear, and on the first clear day a very large amount of triangulation was accomplished, all the more prominent peaks within a radius of about sixty kilometres being observed. Gebel Abu Hamamid forms a culminating point on the Nile — Red Sea watershed, its eastern parts draining to Wadi Huluz