Page:Travels to Discover the Source of the Nile - In the Years 1768, 1769, 1770, 1771, 1772, and 1773 volume 3.djvu/735

 THE SOURCE OF THE NILE. 709

of water comes in to Egypt, or what quantity of ground it is fumcient 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 fwept Cairo and all the Delta into the Mediterranean, and if it mould not do that, it would retire fo late from the fields as to leave the ground in no condition to be fown that yean

I do 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 higheit part of f'gypt, and even when the Nile has rifen to its greatefl height they ftiLl are obliged to water thofe fpots 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 flream, 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 flagnated at the foot of the hills, till accumulated as the flream 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 contact with the current of the Nile, by known laws it mufl par- take the fame motion with it, and fo all Egypt become one torrent.

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