CHAPTER IV 
VOYAGE UP WHITE NILE —Continued 
(n) The Forest-Region 
[Kor do fan) 
Roughly speaking, it is at a point about 150 miles south 
of Khartoum that the last vestiges of the Eastern Sahara 
gradually peter out; we enter a new geological region and 
the Nile assumes a totally fresh character. Instead of 
a broad shallow stream as hitherto, flowing through 
desert and low islands, devoid of distinctive bounds, the 
river is now restricted to a fixed and narrower channel 
with solid banks fringed and beautified by abounding 
tropical vegetation. The scene has changed. 
At once the traveller is confronted with many new 
things. I will specify four :—the papyrus, with its million 
mosquitoes; the seroot-fly, and the sacred ibis in its true 
home. By these indices the traveller may know that 
here he is entering upon a new “zoological zone.” The 
Palaearctic region he is leaving behind : in front lies that 
of Ethiopia. 
A fifth object can never be passed unnamed by any 
who feels the pride of British race—that wondrous railway 
bridge, a tracery of latticed girders, that here spans White 
Nile, no whit less a world’s wonder than the Barrage of 
Assouan, and surrounded by nothing but Afric’s starkest 
wilderness. The bridge itself is all the passing voyager 
sees; yet it is a symbol, a single link in the chain of 
tremendous works that British enterprise in its silent, 
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