422 



PHYSICAL GEOORAl'IIY. 



splendour, not solely to her revolutions and changes of sovereigns, but also to her having 

 been invaded by the desert, deprived by it of a tract of land by which her wants have 

 been abundantly supplied. The preceding paragraphs require some modification, 

 for, though the sand has spread over the irrigated land on the west of the Nile, where 

 valleys open, running out towards the Lybian desert, yet this effect is by no means 

 general throughout the valley of the river, while in other places the alluvial deposit from 

 it has been extended over a wider surface, compensating for the loss from the sand-flood. 

 The plain of Thebes, in the time of Amunof III., about 1430 u. c., was not more than 

 two-thirds of its present breadth. The alluvial mud around the statues of that monarch, 



I'lains of Tliebes. 



which has been collected to the height of nearly seven feet, rests on sand, which shows 

 that if the desert has invaded the cultivable soil yielded by the Nile, the river has returned 

 the visit. While great and disastrous changes have undoubtedly taken place at many 

 points in the physical condition of the country, since the time when the gigantic statue 

 of Memnon was erect, and the temples were frequented, the social and political causes 

 have been far more influential in reducing Egypt from a state of advanced civilization to 

 a level with the " basest of kingdoms." 



The aspect of the whole region of deserts, extending with few interruptions laterally 

 through the heart of the old world, where the sand lies loose, fluctuates under the 

 influence of the wind. The finer particles, caught up by it, are drifted to some arresting 

 object, the carcase of a camel, a block of stone, or a shrub, around which they collect, and 

 form those mounds which relieve the level surface, and are variously modified under the 

 action of the cause that produces them. In several localities upon the great plain of 

 ancient Babylon, these sandhills appear, styled by the Arabs El Aiyat, a miracle, or lyad, 

 a large heap of sand, or Wilayat Beni Ismael, the dominions of the sons of Ismael. They 

 occur on the level plain, and exhibit the curious phenomenon of constantly shifting their 

 place and varying in amount, and yet always remaining in the same general locality. 

 They are thought to owe their existence to the presence of springs, which moisten tliu 

 sand and cause its accumulation, while the prevailing winds alter their form without 

 varying their position, owing to their bases having a fixed point of attraction. To the 

 Arabs they are objects of superstition, who look upon them as the sepulchres of brethren 

 fallen in battle, and hence recognise them as the dominions of the sons of Ismael. The 

 lamented Sir A. Burnes mentions vast fields of soft sand formed into ridges lying between 



