We had heard at Gondokoro of a remarkable obstruction in the White Nile
a short distance below the junction of the Bahr el Gazal. We found this
to be a dam formed by floating masses of vegetation that effectually
blocked the passage.
The river had suddenly disappeared; there was apparently an end to the
White Nile. The dam was about three-quarters of a mile wide, was
perfectly firm, and was already overgrown with high reeds and grass,
thus forming a continuation of the surrounding country. Many of the
traders' people had died of the plague at this spot during the delay of
some weeks in cutting the canal; the graves of these dead were upon the
dam. The bottom of the canal that had been cut through the dam was
perfectly firm, composed of sand, mud, and interwoven decaying
vegetation. The river arrived with great force at the abrupt edge of the
obstruction, bringing with it all kinds of trash and large floating
islands. None of these objects hitched against the edge, but the instant
they struck they dived under and disappeared. It was in this manner that
a vessel had recently been lost. Having missed the narrow entrance to
the canal, she had struck the dam stem on; the force of the current
immediately turned her broadside against the obstruction, the floating
islands and masses of vegetation brought down by the river were heaped
against her and, heeling over on her side, she was sucked bodily under
and carried beneath the dam. Her crew had time to save themselves by
leaping upon the firm barrier that had wrecked their ship. The boatmen
told me that dead hippopotami had been found on the other side, that had
been carried under the dam and drowned.
Two days' hard work from morning till night brought us through the
canal, and we once more found ourselves on the open Nile on the other
side of the dam. The river was in that spot perfectly clean; not a
vestige of floating vegetation could be seen upon its waters. In its
subterranean passage it had passed through a natural sieve, leaving all
foreign matter behind to add to the bulk of the already stupendous work.
All before us was clear and plain sailing. For some days two or three of
our men had been complaining of severe headache, giddiness, and violent
pains in the spine and between the shoulders. I had been anxious when at
Gondokoro concerning the vessel, as many persons while on board had died
of the plague, during the voyage from Khartoum. The men assured me that
the most fatal symptom was violent bleeding from the nose; in such cases
no one had been known to recover.
