364 ROCK CARVINGS BY SAND-DRIFT. 



and the eddying clouds of sand and dust; there is 

 therefore great difficulty in the matter, and so caravans 

 generally halt during severe storms, unless questions 

 as to water supply are very pressing. 



The force with which the sand, and even small 

 pebbles, are driven by the violence of the wind, on 

 these occasions, is at times quite phenomenal. To 

 face it at all, a man requires to have his eyes protected 

 with closely fitting sand goggles, and the rest of the 

 face, below the eyes, had better be protected by a 

 handkerchief, used as a veil a plan which we have 

 successfully adopted in a very bad storm. In torrents, 

 it is well known, the force of the current will in course 

 of time wear away the hardest rocks, and mould them 

 into all kinds of curious shapes. The sand drift has 

 very much the same effect as swiftly running water, 

 in this respect, and where it impinges against a mass 

 of rock, by its constant attrition, will carve it into 

 fantastic shapes, very much resembling the action of 

 water, cutting its surfaces into cup-like cavities, of 

 considerable size and depth, like the "pot-holes" in 

 the beds of mountain torrents. In a recently published 

 work, describing a journey in the desert between the 

 Nile and the Red Sea, a photogravure is given of 

 rocks sand -worn in this manner. 



"Another moulding agent," (says the writer of this book) 

 "of little power in northern climates, is here (in the Egyp- 

 tian desert) a potent instrument in producing unfamiliar effects 

 in rock carving. I refer to the sand, driven before the wind, 

 which honeycombs and undermines the hardest rocks. " * 



Many of the curiously eaten away, abraded surfaces 



* On Either Side of the Red Sea, by E. N. Buxton, 1895, p. 5 of 

 introduction part I, "The Nile and the Eastern Desert." 



