136 THEORY OF THE EARTH. 



The memoir by M. Dolomieu respecting 

 Egypt,* tends to prove that the tongue of land 

 on which Alexander caused his famous commer- 

 cial city to be built, did not exist in the days of 

 Homer ; because they were then able to navigate 

 directly from the island of Pharos into the gulf 

 afterwards called Lams Mareotis ; and that this 

 ^gulf, as indicated by Menelaus, was between fif- 

 teen and twenty leagues in length. Supposing 

 this to be accurate, it had only required the lapse 

 of nine hundred years, from the days of Homer to 

 the time of Strabo, to reduce matters to the situa- 

 tion described by this latter author, when that 

 gulf was reduced to the state of a lake only six 

 leagues long. 



It is a more certain fact, that since that time a 

 still greater change has taken place. The sands, 

 which have been thrown up by the sea and the 

 winds, have formed, between the isle of Pharos and 

 the site of ancient Alexandria, an isthmus more 

 than four hundred yards broad, on which the mo- 

 dern city is now built. These collections of sand 

 have also blocked up the nearest mouth of the Nile, 

 and have reduced the lake Mareotis almost to no- 

 thing; while,in the course of the same period,theNile 



in the researches of M. Prony, respecting the alluvial depositions at 

 the mouths of the PoTransl. 

 * In the Journal de Physique, vol. XLIL 



