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thickness; the upper part of the latter is conspicuous throughout the oasis, under- 
lying the alluvium and forming the base of the surrounding escarpments in 
many localities. Below the water-hearing sandstone lies a black clay, never 
yet penetrated by the boring rods ; it is probable that other water-tables exist 
below and such would be invaluable for the irrigation of those parts of the oasis 
where the present supply is unsatisfactory. There seem to be no natural springs 
extant at the present day, the whole of the water-supply being through boreholes, 
both ancient and modern. The old wells, known as ain , aiyun , appear to be mostly 
of early Egyptian and Roman construction, and number over 400; exactly similar 
wells have been sunk by boring plant during the last few decades and are called 
Ur, biydr; there are over 160 of these; all are true artesian wells. At the present 
day the method in vogue is as follows : — a two metre square timbered shaft is 
sunk by hand to the base of the red clay and within this is built up a watertight 
wooden pipe, 35 cm. in diameter, made of ‘sunt’ (a species of thorny acacia), the 
surrounding space being packed with clay. Sinking is continued in the sandstone 
with the boring machine until a satisfactory flow of water is obtained. Many 
of the older wells in the oasis have become choked up, and although some have 
been successfully cleaned out by the inhabitants, but the process is costly and 
laborious and frequently fails. The work is done by divers, a small but hardy 
class only found in Dakhla and Farafra. 
The output of wells is determined in a somewhat rough and ready manner by 
measuring the depth of water passing over a weir fixed in the stream. It is 
reckoned in qirats, one qirat being a water-section of 64 square centimetres; from 
some test observations in Kharga Dr. Ball deduced the average value of a qirat, 
as measured in that oasis, as 230 litres a minute. The total water-output in 
Dakhla (1096 qirats) may thus be taken as approximately representing a dis- 
charge of 132 million cubic metres per annum, and taking the cultivated lands 
as 25,500 acres the duty is 6,130 acres per cubic metre per second. That the 
water-supply could be largely increased, and the limits of cultivation greatly 
extended, admit of no doubt, but with the free hand accorded the natives during 
the last few decades a considerable amount of damage has been done throughout 
the oasis by the injudicious sinking of wells. Promiscuous boring is fatal, and 
strict and efficient control of all boring operations imperative. Considering the 
number of wells abandoned owing to a slight fall in the water-level having caused 
them to cease running at the surface, the importance of lifting appliances, in the 
shape of shadufs, saqias, or windmills, is evident, but until a few years ago the 
oasis was destitute of such appliances; a number of saqias have recently been fixed 
in the village of Mushia and have met with success, but it is not an easy matter to 
persuade the inhabitants to have recourse to lifting appliances of any description. 
Some of the Dakhla wells are of considerable depth ; Bir-el-Dinaria, the most 
northerly in the oasis, is 144 metres deep and its water emerges with a temper- 
ature of 39*5° C. The best wells yield 9 or 10 qirats, though before the modern 
boring operations the output of some was as much as 16. The terms ‘artesian’ 
and ‘ thermal ’ may fairly be applied to the Dakhla wells, and it is noteworthy 
that the temperatures as a whole increase from south to north. The thermal 
character of the springs may be considered to be due to the great depths from 
