March 7, 1895J 



NA TURE 



445 



bestow it on tracts where il is of priceless value, more thin 

 taking the place of rain in watering the fields. 



The next functi m of a river is to f ■rm a hisjhwiy throue;h the 

 land, and for most of it* course ihc Nile fulfils this duty well 

 too. Gordon considered it possihle for steamers to ascend the 

 Nile during the II loiU from its m mth to the Fola ra lids a dis- 

 tance of ahoiit 3040 miles ; "lut at other seasons, the sixcitaracts 

 cannot be passed. Leaving out the iioo miles which they 

 occupy, there is an unbroken 750 miles In the lower, and nearly 

 1200 miles in the upper river. I cannot look on it as probable 

 that it will ever pay to make navigable canals and locks round 

 these cataracts, as it would entail so much hard rock-cutting. 



Another function of a river is to promote industry by the em- 

 ployment of its water-power. We know how valuable is ihis 

 power eN'en in England, and how much more in countries like 

 .Switzerland, where it abounds, and on the great livers of 

 America. Excf-ptinga fewvery rudewooden " heels in tlieFayi'rn, 

 I do not know, through all the annals of the past, of a single 

 water-wheel ever turned by the power of the Nile. But that 

 power exists to an almost unlimitrd cx'ent. .\nd may we not 

 prophesy that some day in the future, when ihit long stretch of 

 Nubian cataracts has fallen into civilised hands, and when we 

 know how to transmit electric energy with economy, that ilien 

 our descendants will draw wealth to K^ypt from its chain of 

 barren cataracts? 



As a drainage outlet to a continent, as a long highway, as a 

 source of power, the Nile is great ; but not so much so as many 

 other rivers. Its unique pr sition is due to the benefit it confers 

 on Egypt in turning it from being a desert into being the richest 

 of agricul uial lands, suppor'ing wi'h ease a population of about 

 six hundred to the square mile. Herodotus truly said Egypt is 

 the gif of the Nile. It mor^ than supplies the absence of rain, 

 and this it does, first, by the extraordinary regularity with which 

 it rises and falls ; and secondly, by the fertilising matter which 

 the wati-rs carry in suspension, and bestow upnn the land. 

 Imagine what it would be to the English farmer if he knew 

 exactly when it would rain and when it would be sunshine. 

 When the Irigaiion Department of Egypt is properly admin- 

 istered, the Egyptian (armer possesses this certainty, and he has 

 (his further advantage — that it is not merely water that is poured 

 over his lands, hut, during nearly half the year, water charged 

 with the finest m inure. 



According to the early legend, the rise of the Nile is due to 

 the tears shed by Isis over the t'lmb of Osiris, and the texts on 

 the Pyramids allude to the night every year on which these 

 tear-drops fa!). The worship of Isis and Osiris has long passed 

 away, hut to this day every native of Egypt knows the LaiUt 

 en Nttktah^ the night in which a miraculous drop falls into the 

 river, and causes it to rise. It is the night of June 17. 

 Herodoius makes no allusion to this legend of Osiris. In his 

 time, he says, the Greeks gave three reasons for the river's rise. 

 He believed in none of them, but considered, as the most 

 ridiculous of all, that which ascribed the floods to the melting 

 of snows, as if there c )uld possibly be snows in such a hot 

 region. It was many centuries alter Herodotus' time when the 

 snowy mountains of Central .Africa were discovered. 



The heavy rains commence in the basin of the White Nile 

 during .\pril, and first slowly drive down upon Egypt the green 

 stagnant waters of that marshy region. These appear at Cairo 

 about June 15. About a fortnight later the real fl >od begins, 

 for the rains have set in in Abyssinia by May 15, and the 

 Blue Nile brings down from the mountains its supply of the 

 richest muddy water. It is something of the colour and nearly 

 of the consi^tency of chocolate, and the rise is very rapid, a;, 

 much sometimes as 3 feet per diem, for the Alhara torrent 

 having saturated its great sandy bed, is now in full flood also. 

 The maximum flood is reached at Assouan about September i, 

 and it would reach Cairo some four days later, were it not that 

 during August and Sep ember the water is being diverted on to 

 the land, and the whole Nile valley becomes a great lake. For 

 this reason the maximum arrives at Cairo about the beginning 

 of October. The rains cease in Abyssinia about the middle of 

 September, and the floods of the Blue Nile and Athara rapiiUy 

 decrease ; but in the meantime the great lakes and marshes are 

 replenished in the upper regions, and slowly give off their sup- 

 plies, on which the river subsists, until the following June. 

 \ early this phenomenon presents itself in Egypt, and with the 

 most marvellous regularity. A late rise is not mue than about 

 three weeks later than an early rise. In average years the 

 height of the flood at .Assouan is about 25A feet above the 



minimum supply. If it rises 29 feet above this minimum, it 

 means peril to the whole of Egypt, and the irrigation engineer 

 has a hard time of it for two months. If the river only rises 

 20 feet above the minimum, it means that whole tracts of the 

 valley will never be submerged. Such a poor flood has 

 happened only once in modern times, in 1877, and the result 

 was more serious than the devastation caused by the most 

 violent exce^.s. 



The mean flood discharge at Cairo is about 280,000 cubic 

 feet per second, the maximum about 400,000. The mean 

 lowest Nile is about 14,000 cubic feet per second at Cairo, but 

 some years there is not more than 10,000 cubic feet per second 

 pa sing Cairo in June, and within three months after this m.ay 

 have increased forty-fold. 



Until this century, the irrigation of Egypt only employed the 

 flood wati-rs of the river, and it was this that made it the granary 

 of the world. No doubt, rude machines for raising Nile water 

 were used at all seasons and from all times. But by these it 

 was not possible to irrigate on a large scale, and in reality they 

 were only employed for irrigating vegetables or gardens, or 

 other small patches of land. It must not be thought that 

 the water of the flooded river is ever allowed to flow 

 where it lists over the lands. The general slope of the 

 vallev on each side is away from the river, a feature which 

 the Nile shares with all Deltaic streams. .Along each edge 

 of the river, and following its course, is an earthen embank- 

 ment, high enough not to be topped by the highest flood. 

 In Upper Egypt, the valley of which seldom exceeils six miles 

 in width, a series of embankments have been thrown up, 

 abutting on their inner ends against those along the river's 

 edge, and on their outer ends on the ascending sides of the 

 valley. The whole country is thus divided into a series of 

 oblongs, 'urrounded by embankments on three sides, and by the 

 slope of the desert hills on the fourth. In Lower Egypt, where 

 in ancient days there were several branches of the river, this 

 system was somewhat modified, but was in principle the same. 

 These oblong areas vary in extent from 60,000 to 3000 or 4000 

 acres, and the slope being away from the river, it is easy to cut 

 short, deep canals in the banks, which fill as the flood rises, and 

 carry the precious mud-charged water into these great flats, or, 

 as they are termed, basins of irrigation. There the water re- 

 mains for a month or more, some three or four feet deep, de- 

 positing its mud, and then at the end of the flood it may either be 

 run off direct into the receding river, or, more u-ually, passed off 

 through sluices from one basin to another, and ultimately back 

 into the river. In November the waters have passed oft", and 

 wherever a man and a pair of bullocks can walk over the mud, 

 and scratch its surface with a wooden plough, or even the branch 

 of a tree, wheat or barley is sown, and so saturated is the soil 

 that the grain sprouts and ripens in April or May ivithout a drop 

 of rain or any fresh irrigation. .And a fine crop is reaped. One of 

 our great brewers told me the other day, that when barley grown 

 in this country was spread in the mailing-house, about three per 

 cent, of it must be counted on as not sprouting and being dead. 

 If grain two or three years old was used, as much as twenty per 

 cent, would be found dead. With Egyptian barley, he said, 

 even after several years, you could count on every grain ger- 

 minating. The crop once reaped, the fields remain dry, and 

 crack in the fierce summer heat until ne.>:t flood comes on. 



The tourist who only comes to Egypt to shun " winter and foul 

 weather," knows nothing of the majestic glories of the Nile flood. 

 The ancient Nilometer at the south end of the island of Roda, 

 just above Cairo, is one of the most interesting sights of the 

 place. The water enters from the river by a culvert into a well 

 about 18 feet square, with a graduated stone pillar in the centre. 

 On each side of the well is a recess about 5 ftet wide and 3 feet 

 deep, surinnunted by a pointed arch, over which is carved in 

 relief a Kufic inscription, and a similar inscrijtion is carried all 

 round the well, consisting of verses of the Koran. A staircase 

 goes dovin the well, from the slops of which the initiated may 

 read the height of the water on the pillar ; but they aie few in 

 number, and the hereditary Sheikh of the Nilometer, whose 

 duty it is to keep the record, is a person of some importance. 

 The Nilometer dates from A.n. 861, and I beli<ve in the 

 archives of Cairo may be found the daily record for looo years. 



I need ha-dly tell you that uhen our I'.nglish engineers took 

 the river in hand, we established a number of gauges at Wadi 

 Haifa. Assouan, Cairo, and many other jioinis, on more scientific 

 principles than the venerable Nilometer of the Roda Island. 



After the river has begun to rise, its height is daily chanted 



NO. 1323, VOL. 51] 



