THE SOURCE OF THE NILE. 709 
of water comes in to Egypt, or what quantity of ground it is ° 
fufficient to overflow, unlefs the dykes were to be kept clofe 
till the Nile attained its extreme height, which would be about 
the 25th of September, long before which it would be over 
the banks and mounds, if they held in till then, or have 
{wept Cairo and all the Delta into the Mediterranean, and if 
it fhould not do that, it would retire fo late from the fields 
as to leave the ground in no.condition.to be fown that year.. 
Lpo not comprehend: what idea other travellers have 
formed of the beginning of the inundation of the Nile, as 
they feem to admit that the banks are not overflowed; and 
this is certainly the cafe ; becaufe the cities and villages are 
built there as fecurely as on the highett part of Egypt, and 
even when the Nile has rifen to its greateft height they ftill 
are obliged to water thofe {pots with machines. In another 
part of the work it is explained how the califhes carry the 
water upon the lands, approaching always to the banks as 
the river rifes in. proportion, and thefe califhes being deri- 
ved from the Nile at right angles with the ftream, and carry- 
ing the water by the inclination of the ground, in a di- 
rection different from the courfe of the river, the water is 
perfectly ftagnated at the foot of the hills, till accumulated 
as the ftream: rifes, it moves in a contrary direction back- 
wards again,.and approaches its banks. But when the in- 
undation:is fo great that the back-water comes in conta& 
with the current of the Nile, by known laws it muft par- 
take the fame motion with it, and fo all Egypt become one- 
torrent.. 7 | Va 
, DR 
