THE LIBYAN DESERT. 329 



the wilderness were a special favour of heaven. Nevertheless the sovereigns of 

 Egypt, and after them the Roman and Byzantine emperors, were well aware that 

 these oases were not the happy ahodes sung by the poets, for thither they banished 

 their enemies to perish of weariness and inanition. Thousands of Christians, exiled 

 by their fellow- Christians of different theological opinions, yielded to home- sickness 

 in these dreary " convict stations." Some of the oases, amongst others that of 

 Dakhel, possess the romantic beauty imparted by a superb rampart of cliffs, with 

 their fantastic towers and embattlements rising from 800 to 1,000 feet above the 

 hamlets and palm-groves. But the traveller's admiration is, even here, due mainly 

 to the impression of contrast presented by the patches of verdure to the dismal 

 waste of bare rocks and sand encircling them. He is naturally enraptured when, 

 after traversing the waterless desert, the constant sport of the mirage, he- at last 

 comes upon real streams of water, flowing beneath the shade of leafy groves. But 

 then comes the inevitable feeling of oppression produced by the narrow limits of 

 these garden-plots, everywhere surrounded by boundless wastes, stretching in all 

 directions beyond the horizon. 



The Libyan Desert. 



The sands of the desert form shifting dunes like those on the Mediterranean and 

 Atlantic coasts. Between the Nile Valley and the chain of oases several ranges of 

 these dunes are disposed, nearly all in the direction from the south-east to the north- 

 west, parallel with the course of the river between Assuan and Minieh. The sand- 

 hills do not attain an elevation comparable to those of the French landes ; doubtless 

 the laboratory where rocks are weathered into minute particles are more remote, 

 while the winds are less powerful. A few stunted shrubs, especially the tamarisk 

 plant, are the chief instruments employed by nature in binding the sand in compact 

 masses. Behind these obstacles a little heap is formed, the horns of its crescent 

 curving forward with the wind. Soon the plant is enveloped, and would in a short 

 time be entirely swallowed up, if its growth did not keep pace with the rising 

 sands. 



Thus are formed hillocks, whose mean height scarcely exceed 12 or 14 feet, 

 and on the crest of which is visible the foliage of a tamarisk or some other shrub. 

 A peculiar physiognomy is imparted to the Libyan desert by these low eminences, 

 which in form and colour resemble eroded cliffs, but all of which bear a plant of 

 some kind on their summits or slopes. The sands do not pass beyond any rock}' 

 heights exceeding the mean elevation of the plateau ; they are also arrested before 

 the Pjrramids on the edge of the limestone rocks skirting the valley of the Nile. 

 Hence arose the otherwise groundless and absurd hypothesis that the huge tombs 

 of the Pharaohs were erected to protect Egj'pt from the invading sands of the 

 desert. 



When the west wind prevails, thousands of small streams of red or golden sands 

 overflow from the rocky battlements of the plateau, forming long ridges which 

 here and there encroach on the cultivated lands. In this way the course of the 



