MR. HORNER ON THE ALLUVIAL LAND OF EGYPT. 
descendu de 1^ a 2 pieds, et partout il degrade les bords a tel point, qu’on voit a 
chaque moment une serie d’avalanches du plus beau terroir noir imaginable:” and 
on the following day he says, “Nous sommes arrives a Girgeh, une des villes de la 
haute Egypte, qui etait trois fois plus grande il y a quelques annees qu’aiijourdhui, 
mais un courant du Nil qui s’est determine centre la colline friable sur laquelle elle 
est batie, en enleve des quartiers entiers de terns a autre. Une portion des maisons 
et une mosquee, dont la moiti^ est deja tombees dans le Nil, ressemblent aux 
gravures du Diable Boiteux, seulement que ces debris ne sont pas habites.” The 
sediment of one year is also carried back into the river the following year from 
another cause: — “ Pendant trois ou quatre mois de Fannie, la surface de FEgypte, 
d^nu^e de vegetation, s^che et pondreuse, est balayee par des vents violents, qui 
soul^vent dans les airs la poussi^re du sol, en laissant precipiter une partie dans le 
fleuve, qui Fentraine a la mer, et en dispersent une autre partie dans les deserts, ou 
Faccumulent sur d’autres portions de FEgypte*.” At a distance from the river, 
especially in those parts which are in the vicinity of valleys or gorges, in the lateral 
ranges of hills, blown sand from the desert is often mixed with the mud of the river 
that is spread upon the land. 
In all calculations, therefore, as to the secular increase of the deposit, by measure- 
ments of its depth, we must take into our consideration whether the pits or the 
borings have been made in places least liable to these irregularities ; whether the 
solid matter held in suspension may not have been augmented by portions of former 
deposits washed or falling into the stream ; and whether the mud deposited by the 
river has had no intermixture of blown sand. 
Tlie following observation of the traveller Ruppell is a remarkable indication of 
an accumulation of the Nile sediment in the Faium, at a distance of about twenty- 
five miles from the left bank of the river : — “ I had a desire to visit Lake Moeris and 
its islands, and quitted Medina in a north-east direction, travelling over very fertile 
plains. In the neighbourhood of a large village called Fedimin, we passed the dried- 
up bed of a very deep canal, in the side of which I saw, to my great surprise, hori- 
zontal beds of the mud of the Nile, having a depth of sixty feet'f-.” 
THE RECENT RESEARCHES. 
The first step which I had to take in this inquiry was to decide upon the situation 
in which the proposed vertical shafts should be sunk. As the neighbourhood of 
Cairo might afford great facilities for prosecuting the work, as the standing obelisk 
of Heliopolis is one of the most ancient of the existing monuments, and as the time 
of its erection has been made out on very reliable grounds, I chose that spot. 
Having obtained an introduction to A. C. Harris, Esq,, of Alexandria, well known 
by his active and long-continued researches in Egyptian antiquities, 1 requested him 
* De la Constitution physique de TEgypte, Hist. Nat. ii. 493. 
t Letter in Baron de Zach’s Correspondance Astronomique, vol. vii. p. 245. 
