120 
area to be undertaken, known as the Central Gharbia drainage 
area. The land is divided into categories: good, medium, and 
poor land under cultivation, barren land, land under reclama- 
tion, and land on which at the time of survey there was stand- 
ing water. bean 
A check was put on the field surveyors by the determination 
of the salt-content of large numbers of soil samples taken as 
the work proceeded. It is well recognized that the presence 
or absence of salt is the principal determining factor in the 
fertility of the Delta land. The results showed that the fertility 
is a close approximation to a salt survey, the good land con- 
taining on the average 0°3 per cent., the medium 0’5 per cent., 
and the poor land 0°8 per cent. The barren land may contain 
up to as much as 25 per cent. of salt. 
The close dependence of the fertility on the altitude above 
sea-level, or in other words on the amount of natural drain- 
age, is shown by a comparison of the fertility map with a 
contoured map of the same area. 
THE WATER SUPPLY OF EGYPT, 1918—1914. 
By B. F. E. Keetine, M.A., 
Director of Physical Services, Survey Department, Ministry 
of Finance, Egypt. 
[ApsTrRact. | 
The flood of 1913 was the lowest recorded for over one 
hundred years. A general.account is given of the rainfall in 
the areas from which the Nile draws its supply, and of the 
methods by which the water is utilized in Egypt, with the two 
main divisions of basin and perennial irrigation, the limits of 
which are shown on a map. During winter there is always 
sufficient water for the perennially irrigated tracts, and the 
principal factor in irrigation is the height to which the Nile has 
risen, enabling more or less of the basin tracts to receive water. 
In summer there is often difficulty in providing the perennially 
irrigated areas with sufficient water, and it is then the quantity 
of water which is the controlling factor. 
In 1913 the flood-level at Aswan was 2} metres below normal, 
and 14 metre below that of any previous year since the occu- 
pation. The effect of this on the irrigation of Upper Egypt, 
and the function of the Esna Barrage in providing water to 
basins which otherwise would have been left dry, are explained. 
The low flood was naturally followed by a very bad supply 
during the early summer of tg14. The natural supply reaching 
