PHYSICAL PEATUEES. xxix 
the Arabian desert Jet their female donkeys loose to be served by wild males. Gazelles 
wander over the mountains as well as over the plains, and on the latter and in the 
wadis hares and other rodents are not uncommon. Ovis tragelaphus is associated with 
the foregoing animals, as Professor Schweinfurth in 1878 : pointed out that it was 
found in the neighbouring Wadi Shietun, which opens on the Nile, below Akhmin. 
Dr. Sclater 2 has quite recently recorded its presence in the Wadi Medisa, on the 
authority of Mr. E. N. Buxton 3 , lhjrax syriacus occurs in one of the upper reaches 
of the Wadi Shietun in such great numbers that Professor Schweinfurth has named it 
the " Valle di Hyrax." Natural reservoirs of water are also present in the upper part 
of this valley. 
Wilkinson 4 , who long ago described the general characters of the mountain masses 
of Jebel Kittar and Jebel Dukhan, ascended Jebel Gharib, a very bold and striking 
mountain to the north, overlooking the Gulf of Suez. It attains to an altitude of 
1646 metres above the level of the sea, and near its summit he stalked gazelles that 
had doubtless wandered up the mountain in search of the stray plants M'hich he 
observed growing every here and there under the shade of projecting stones in the 
ravines. The following reptiles have been obtained from the plain below Jebel 
Gharib, viz. : — Stenodactylus elegans, Hemidactylus turcicus, Eremias rulropunctata, 
Psammophis schokari, Cerastes vipera, and C. cornutus. 
The rarity of rain over the great mass of the Arabian desert, more especially to the 
west of the crystalline range of mountains, may be held as entitling that portion of it 
to be designated a desert, but at the same time it should be borne in mind that it is 
a region devoid of rain-gauges. When rain does visit it, it generally falls as a steady 
downpour, particularly severe in the mountainous portion ; but in the wadis to the west 
the floods of water from off the plateaus and terraces rush into them from every side, 
leaping in waterfalls over their steep banks, scouring out their beds, rushing as cataracts 
along the rocky channels with irresistible force, carrying before them the uprooted shrubs 
or burying those that withstand them under heaps of rubble and sand, a mighty 
disintegrating power with a capacity for work that can only be justly estimated when 
it is witnessed in action, or by its effects when viewed immediately after action has 
ceased. As the wadis are , the lines along which animal life is distributed, these 
floods prove destructive more especially to rodent and to reptilian life. 
These storms sometimes assume the character of violent hail-storms : one such was 
experienced by Professor Schweinfurth 5 on the 12th April, 1864, just outside the 
tropics, at Wadi Lekhuma, on the coast of the Red Sea, to the north of Berenice, the 
hail- stones being as large as cherries or pigeons' eggs; and Professor Schweinfurth 
states that Dr. Diimichen, who was staying that day at Thebes, experienced there 
1 Terra Incog. &c. - Proc. Zool. Soc. 1895, p. 84. 
3 See also Buxton, ' Short Stalks,' 1898, p. 106. * Journ. Eoy. Geogr. Soc. ii. 1832, pp. 28-60. 
3 Zeitsch. Gres. Erdk., Berlin, 1865. 
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