At Thebes, the Nile rises about thirty-six feet; at the cataracts about forty; at Rosetta, owing to the proximity of the mouth, it only rises to the height of about three feet and a half. The Nile begins to rise in the end of June, or the beginning of July; that is to say, about, or soon after, the summer solstice, and attains its greatest height in the end of September, or sometimes (but rarely) in the beginning of October; that is, in other words, about or soon after the autumnal equinox. During the first three months of its decrease, it loses about half the height it had attained; and during the remaining six months, it falls more and more slowly. It generally remains not longer than three or four days at its maximum, and the same length of time at its minimum: it may therefore be said to be three months on the increase, and nine months gradually falling. It often remains without any apparent increase or diminution, at other times than those of its greatest or least elevation, and is subject to other slight irregularities. The Nile becomes turbid a little before its rise is apparent, and soon after it assumes a green hue, which it retains more than a fortnight. Its water is extremely delicious even when it is most impregnated with earth; but then the Egyptians (excepting the lower orders) usually leave it to settle before they drink it, and put it in porous earthen bottles, which cool it by evaporation. While the Nile is green, the people generally abstain from drinking the water fresh from the river, having recourse to a supply previously drawn, and kept in cisterns.
The width of the Nile where there are no islands is in few parts more than half a mile. The branches which enclose the Delta are not so wide, generally speaking, as the undivided stream above; and the river is as wide in most parts of Upper Egypt as in the lower extremity of the valley.
The rapidity of the current when the waters are low is not greater than the rate of a mile and a quarter in an hour; but during the higher state of the river, the current is very rapid, and while vessels with furled sails are carried down by the stream with great speed, others ascend the river at an almost equal rate, favoured by the strong northerly winds, which prevail most when the current is most rapid. When the river is low, the wind from the north is often more powerful than the current, and vessels cannot then descend the stream even with the help of oars.
I believe that I shall have occasion to add a few more words on the Nile some days hence, when I hope to send you the remainder of the general sketch.
Meanwhile, believe me to remain, &c.
LETTER VI.
October 13th, 1842.
My dear Friend,
Since I last wrote to you, the weather has continued intensely hot; but during the last three days almost constant lightning throughout the evening, though succeeded by excessive heat during the nights, has given us hope of speedy relief. This heat is attributed to the present state of the Nile, which has continued most unusually increasing up to this time (the 13th of October), and given rise to serious apprehensions; for unless the water drain quickly off the land when the river begins to fall, it is feared that a severe plague may ensue. In such a case, we propose going up to Thebes for four months, but we earnestly hope it may please Almighty God to avert so dreadful a calamity as a pestilence must inevitably prove. I now resume the sketch I left unfinished in my last letter.