— 38 
of Oufile. While the sudd floats it is not so bad as when it sinks, as it 
has done at block No. 15 north of Gaba Shambe, where the Nile has 
left its course for 37 kilometres owing to sunken sudd. When the sudd 
sinks, its becomes putrid and especially loathsome. 
The Sudd region is unmistakably, as Lombardini pointed out years 
ago, an old lake which has silted up and become full of peat and sand 
deposits. At one time the lake must have had an extreme length of 400 
kilometres and width of 400 kilometres and been a larger sheet of water 
than lake Victoria. The So bat river flowed into it, and the Blue 
Nile may have flowed backwards up the bed of the present White Nile 
for tens of thousands of years. The north-east corner has been better 
filled with deposit than any other part. 
The dense masses of papyrus and water-grasses which shut out the 
horizon in every direction intimidated the expedition sent up the Nile 
by Nero, and it returned northwards without having accomplished 
anything. From Nero’s time to that of Mehemet Ali little was known of 
these regions. Mehemet Ali made a determined effort to discover 
what lay beyond these inhospitable regions, and sent up a well-equipped 
expedition under D’Arnaud. 
One of the earliest descriptions of the Nile between the fifth and 
tenth parallels of latitude is by Werne, who accompanied D’Arnaud’s 
expedition sent by Mehemet Ali in 1840-1841. The expedition found 
the channel of the White Nile and Albert Nile easily navigable between 
December and March. The Albert Nile between 7° and 9° N. lat. had 
apparently a mean width of 120 metres, depth of 5 metres, and velocity of 
about 60 centimetres per second, giving a discharge of some 400 cubic 
metres per second. In this first description of the river the fact that 
strikes one most forcibly is the omission of the Bahr Zeraf. Neither 
the inlet nor the outlet are mentioned, though the Sobat, the Gazelle, 
and numerous insignificant streams are minutely recorded. Practically 
the whole of the water was confined to one stream, and that a good 
one. The water level in winter was found to be some 50 centimetres 
below the general level of the berm, and about 60 centimetres above 
this level in flood. The swamps contained offensive and fetid water, 
which mixed with the waters of the rising flood and helped to pollute 
the stream on the first rise of the river. Between the river and the 
swamps in its southern reaches were numerous cuts and openings, some 
natural and some artificial, made by the aborigines for fishing purposes. 
While traversing the swamps, the waters of the river in flood lost 
