Notes. 
449 
line of the dam and carry the supply of the Nile during summer and 
winter. . . . The method adopted for dealing with these deep channels 
was to construct “sadds” across them upstream and downstream 
of the site of the dam ; these sadds were then made sufficiently 
watertight to allow of the area between them being laid dry by 
pumping. It was necessary to make the sadds on one side of the 
dam of stones so as to stand the great rush of water: these sadds 
were made before the great rush of water, to a level of 5 metres below 
high Nile, and on the north side of the dam. Thus, when the flood 
was subsiding, still water was easily obtained upstream of the sadd, 
and a sandbag sadd was commenced on the other side, so that the 
three channels were cleared by the end of the year/ And the word 
‘ sadd/ as meaning a temporary or subsidiary dam, of earth or stone 
work, is found in other parts of the article now being quoted from. 
It seems probable the use of the word ‘ sadd/ as the name for the 
vegetable obstructions in the Upper Nile, was taken from the ordinary 
use of the word on lower parts of the river where irrigation has long 
been in vogue. The smallest kind of sadd is the two or three 
spadesful of earth with which the cultivator (in India at least) turns 
canal or rain water from one compartment of a field into another. 
The Clearing of the ‘ Sadd l 
A recent number of the Geographical Journal contains a paper 
on the ‘ Sadd’ of the White Nile, by Dr. Edward S. Crispin, explaining 
the method of opening up the true river bed employed by Major 
Matthews, who commanded the Sadd Expedition of 1 901-2. The 
first difficulty is to find the position of the river bed; this is done 
by probing, the depth suddenly increasing to 15 to 20 feet. Next, 
the top growth, consisting mostly of Papyrus, is cut down or burnt. 
Men are then landed on the cleared surface, and the sadd cut 
along the river banks with saws ; next transverse cuts are made, 
dividing the sadd into blocks convenient for the steamer to tear out. 
The bows of the steamer are run into the block, and the loop of 
a steel hawser, both ends of which are made fast to the steamer, 
is passed over the bows and trodden into a trench cut on the surface 
of the block. The steamer then goes full speed astern, men standing 
on the hawser to keep it in position, and after a number of trials the 
block is torn away and cast adrift to float downstream, where it is 
gradually disintegrated. 
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