tfie present and former Leveh of Egypt. 221 



is not worthy of notice, nor can it be attributed in any way 

 to tlie advance of the desert upon the land of Egypt. In 

 many countries, as in France, about Dunkii'k, the Landes, and 

 other places, as in Scotland, near Nairn, and in several parts 

 of Europe, sand-drifts occur of great size and extent ; but the 

 same theories are not formed upon their aggressions ; and we 

 have in this a proof how far opinions are influenced by the 

 name and by the idea of a desert. I am far from aifirming 

 that no encroachment of the sand takes place ; my argiunents 

 are only intended to shew that, taking into consideration the 

 relative advance of the sand, and of the alluvial deposit, the 

 balance is greatly in favom- of the latter, and the result is, 

 that, whatever partial injiu-y the sand may have in its power 

 to inflict upon certain spots, the extent of the land is con- 

 stantly increasing, and the number of square miles of arable 

 soil is much greater now than at any previous period. 



1 must also make some remarks regarding the nature of the 

 desert, which will be found to difi"er much from received 

 opinion, as the simple mention of ranges of primitive moun- 

 tains, reaching an elevation of several thousand feet, would 

 suffice to .show. I allude now to the desert lying between the 

 Nile and Red Sea; but in order to give a just notion of 

 the' tract, and the nature of the mountains in several parts, I 

 must refer to my map, and to the accompanying sections in 

 different latitudes. 



The leading characteristic of this desert, particularly in the 

 northern part, is its gradual ascent from the north of the Nile 

 to a certain distance eastward, where you arrive at a plain, 

 nearly level and of some extent, from which all the valleys or 

 torrents running in a westerly direction, empty themselves in- 

 to the Nile, and those to the eastward into the Red Sea, fol- 

 lowing a descent in the opposite direction to the coast. This 

 section, taken east and west, about Lat. 29° (see plate No. 7), 

 will explain the appearance of the desert in that part. 



The moimtains there are all limestone : the ascent from the 

 Nile to A is about 30 miles ; the high plain A B is about 16 

 miles broad, and the descent then commences towards the Red 

 Sea, which is about 50 miles distant. 



In that part where the primitive range commences and join» 



VOL. XXVIII. NO. LVI, MARCH 1840. Q 



