February i8, 1909] 



NATURE 



46: 



Mood water being greater than is required at high 

 Hoods and deficient in low floods and in summer, 

 a system of dams at different parts of the river has 

 been carried out for storing and regulating the supply. 



The princfpal crops grown along the Nile are 

 wheat, sugar, cotton, rice, maize, and other smaller 

 vegetation. Where the supply of water is sufifi- 

 cient, two crops can be obtained in one year. The 

 cuitivafion of cotton is rapidly extending, the value 

 of this crop alone now being nearly as great as the 

 whole revenue of the country. 



The first great work for improving the irrigation 

 undertaken by the Works Department after the 

 British obtained control in i8Sj was the completion 

 of the great barrage, or dam, at the head of the 

 Delta. This had been constructed by the French 

 engineers for the purpose of holding up the Nile water 

 to a height of 15 feet, sufficient to provide the neces- 

 sary head for feeding the irrigation canals. Owing, 

 however, to defects in the construction, it had never 

 been possible to raise the level more than 5 feet. 

 I'nder the direction of Colonel .Scott-Moncrieff, the 

 foundations were strengthened, and other necessary 

 repairs carried out, with the result that the full 

 head of water can now be maintained, and 

 the land can be efficiently irrigated. Also, bv 

 the construction of another barrage, at a cost of 

 2jo,ooo(., half-way between Cairo and the sea, the 

 irrigation is rendered still more effective. Owing 

 to these works the value of the cotton crop has 

 been increased from 75 to 15 millions of pounds, and 

 the cultivated area increased by a million acres. 



For regulating the supply of water in Upper 

 Egyptj about seven years ago the great barrages, or 

 dams, at Assouan and .\ssiout were built across the 

 river at the head of the cultivated system of Upper 

 Egypt. These works were carried out by the firm 

 of .\ird and Co. for the English Irrigation Depart- 

 ment, the contract price being 2,000,000/. These 

 dams act as regulators of the water supply in 

 summer, and have practically doubled the supplv 

 available. It was stated by Lord Cromer, in one of 

 his reports soon after they were completed, that the 

 effect of these works was to increase the rental of 

 the land to 3L an acre, in addition to a tax of los. 

 that is levied to pay the cost. A practical demon- 

 stration of their value was afforded in 1902, when 

 ihe Nile flood was a very poor one, and the agri- 

 cultural outlook was very critical, for a large area 

 of cropping was in danger of being entirely lost 

 through want of irrigation. This, however, was 

 prevented, owing to tlie water stored bv the dam at 

 Assiout, and cropping estimated of the value of 

 500,000?. was saved. Thus the whole cost of this 

 dam was paid for in this one season. 



The dam recently opened by the Khedive is near 

 Esneh, a town of 25,000 inhabitants, situated on the 

 Nile 643 miles from the Mediterranean and 110 miles 

 below the dam at .\ssouan. It has been constructed 

 for the purpose of storing the flood water and 

 providing perennial irrigation to a tract of land con- 

 ^ taining 250,000 acres, on which at present onlv one 

 crop of cereals can be grown. When irrigated this 

 land will be capable also of growing a second, 

 or summer, and more profitable crop of sugar or 

 cotton. 



The dam is somewhat similar in construction to 

 those above described. It consists of a masonry struc- 

 ture containing 119 piers, spaced 16J feet apart, and 

 connected by arches, on which is carried a roadway 

 across the Nile about half a mile long and 19^ feet 

 wide. The openings between the piers are fitted with 

 upper and lower doors, or gates, resting in grooves, 

 which can be raised or lowered bv machinery so as to 

 regulate the discharge of the water through" the dam. 

 NO. 2051, VOL. 79] 



For the use of the navigation a lock has been provided 

 which is 262J feet long and 52^ feet wide. 



The dam at Assouan rested on the granite bed of 

 the river, but at Esneh the substratum was sand, which 

 extended to a considerable depth below the bed of the 

 river. To carry the structure, therefore, a continuous 

 floor had to be made 2950 feet long and 98J feet 

 wide. This floor consists of cement concrete 35 feet 

 thick, on which is bh feet of rubble masonry laid 

 in cement and paved with granite setts. To prevent the 

 water finding its way under this floor, when it is 

 held up, two rows of iron sheet piles were driven 

 fo a depth of 13 feet below it, 6ii feet apart, across 

 the bed of the river, the space between being filled 

 with clay puddle pitched with limestone. On the 

 down-stream side, to prevent erosion of the river 

 bed by the water pouring through the arches when 

 the doors are open, a floor was laid with a pitching 

 of limestone 131 feet wide. 



The superstructure was built of sandstone, granite 

 being used for the lock. This sandstone was obtained 

 from a quarry fifty-seven miles distant, the quantitv 

 used amounting to 166,000 cubic yards. The granite, 

 of which So, 000 cubic yards was used, was brought 

 down the Nile in barges from .Assouan, a distance of 

 no miles. The cement, the iron piles, and the 

 machinery all came from England. 



From Sooo to 10,000 natives were employed, 

 Italians being engaged in preparing the stone. 

 The work was supervised by English foremen and 

 overseers. 



The preliminary works, including the opening out 

 of the quarries, temporary railways, of which twenty- 

 four miles were used, workshop's for the men, arid 

 oftices, were commenced in the spring- of 1906, the 

 permanent work being begun in the following- 

 November. Three years were allowed by the 

 contract, and as the work w-as completed in 

 half the specified time, the district is thus 

 given the benefit of an extra season's irriga- 

 tion. 



The works were designed bv Mr. Webb, the 

 engineer of the Egyptian "Works 'Department, under 

 the direction of Mr. .Macdonald, the director of reser- 

 voirs, and carried out by Messrs. .Aird and Co., the 

 same contractors who constructed the Assouan and 

 .Assiout dams. The cost was more than i,ooo,oooL 



T 



ELECTROCHEMICAL INDUSTRY. 

 HE report referred to below' is based in the 

 main on information obtained during visits to 

 certain countries in Europe and to the United States 

 and Canada, including British Columbia. The Gart- 

 side scholarships were established in 1902 by Mr. J. H. 

 Gartside, and are administered by the University of 

 Manchester. The scholar who ' obtains the grant 

 must first study in the university, and the remainder 

 of his time i-nust be devoted to an examination of 

 subjects bearing upon commerce or industry in 

 Germany, Switzerland, or the United States of 

 .America. It is intended that each scholar shall select 

 some industry or business for examination, and in- 

 vestigate this comparatively in the United Kingdom 

 and abroad. 



The report is of particular interest because it deals 

 with a subject which is of comparatively recent 

 growth, and which has remarkable potentialities. In 

 fact, as the author says, few chemical processes have 

 escaped being affected in a greater or less degree by 

 the application of electrical methods. 



1 " Some Electrochemical Centres." By J. N. Pring. Being No. 7 of 

 the Gartside Reports on Industry and Commerce. Pp. xiii-Fi^y. (Man- 

 chester : University Press, 1908.) Price is. 6d. net. 



