135 
of Edinburgh, Session 1869-70. 
of South Africa, is the difficulty of making use of these rivers as 
highways into the continent. The coast rivers of the Lake Begion, 
or, indeed, of the whole of Eastern Africa, are barred at their 
mouths by the aggregated debris which they carry down, raised in 
banks on the coast between the downward current of the river and 
the opposing monsoon, or trade wind, blowing towards the coast. 
If this bar is passed at the mouth, still the navigation even of the 
largest rivers cannot cross the edge of the plateau where cataracts 
and rapids form a new obstruction. The vast lakes of the interior, 
and their great connecting rivers, however, present great lines of 
navigable water, which in a higher civilisation would be utilised 
for busy traffic, the line of the Nile basin in the Tanganyika and 
Albert lakes alone affording an unbroken voyage of about 900 
English miles. 
Piaggia, the traveller who has been nearest to the great lake 
which lies to the north-west of the Albert Nyanza, reports a great 
river called the Buri, flowing to westward, at some days’ journey 
from Kifa (his furthest point), and which issues out of his great 
lake. The same river has been reached, at some distance from its 
supposed outlet, by the brothers Poncet (French ivory traders), who 
have long trafficked in this region, and they express the opinion 
that this river unites the equatorial lakes with Lake Tchad, by 
means of the Shari river. This they proposed to prove by an ex- 
pedition on it in boats. The question, What becomes of this great 
river? which, at its outlet from the lake, is so large as to be only 
passable in boats, is an interesting one. It is certainly no tribu- 
tary of the Nile, and the two most probable lower courses which 
it may have are those of the Shari to Lake Tchad, or of the Benue 
river to the Niger. If it ultimately proves to flow to Lake Tchad, 
it will give a striking evidence of the vast amount of evaporation 
which must exist in the region of that lake, since it has no outlet ; 
but the Benue river seems to be its most probable course, for at its 
confluence with the Niger, the Chadda, or Benue, is the larger river. 
The Ogowai river is also a possible lower course for the Buri, but 
if the lake reported by Piaggia be, as we suppose, on or beneath the 
northern edge of the plateau of South Africa, it seems only natural 
that the river from it should seek the lower land to northward, 
than turn westward along the northern slope of the plateau. 
