This drifting of the sands had been in operation, 

 probably, from the beginning of time, and bad con- 

 tributed no small portion to the elevation of tbe bed, 

 or bottom of this gulf to the surface of the water, and 

 which was necessarily so, or the plains of Egypt, had 

 they been formed of the alluvion of the river alone, 

 would probably have remained to this day as barren as 

 a slate roof, or the mountains in their vicinity. 



The alluvion brought down by the Nile, and most 

 other rivers, as I have before remarked, is, in general 

 composed of the alluminous, or clayey portion of the 

 soil above, which, being light, is carried to a great 

 distance, and, when deposited in a sufficient quantity, 

 forms a slimy mud, such as that of the Nile is des- 

 cribed to be, and which, most probably, differs but 

 little from the slimy mud which is collected and form- 

 ed by the same process, in all our docks and slips. 



' The mud, or alluvion of the Nile is represented as 

 being " of an exceedingly light nature, and feels to 

 the touch like an impalpable powder."* This is the 

 character of clay when dry ; and such is the mud of 

 the Nile, that when deposited in low places, and in a 

 sufficient quantity ; or when dug out of the canals and left 

 exposed to the intense heat of the sun ; it becomes 

 hard, (unless tempered with sand,) and cracks open, 

 as do almost all lands where clay predominates. 



Hence, the necessity, of its being tempered with 

 sand to render it productive : and hence it is, with- 



* Shaw's Travels, page 432, 



