Hope . — The ‘ Sadd ’ of the Upper Nile . 503 
£ As we progressed farther the river islands became more 
and more narrowed by the surrounding masses of impenetrable 
grass. The ambatch is here almost excluded by the Vossia 
grass, but only to appear at the mouth of the waters. 
. . . Here we came across numbers of Shillooks fishing 
in their light canoes of ambatch, darting through the water 
almost as quickly as the fish themselves. ... So light are these 
canoes that one man can carry three of them on his shoulders, 
although each canoe is capable of holding three men. From 
a dozen shoots of ambatch of about three years’ growth a canoe 
of this kind can easily be produced ; at about six feet high 
the stem goes off rapidly to a point, so that a bundle of them 
needs only to be tied together at the extremities, and there is 
at once obtained a curve that would grace a gondola.’ 
Here then is a direct conflict of testimony. On the one 
hand Dr. Schweinfurth, a great traveller and explorer as well 
as an eminent botanist, states from personal observation that 
the ‘ Ambatch,’ Herminiera elaphroxylon , is the true origin of 
the ‘grass-barrier’ which blocks up the Upper Nile ; and, on 
the other hand, we have Sir William Garstin, an eminent 
engineer, holding a high post under the Egyptian Govern- 
ment, who spent months on the Upper Nile, and watched the 
operations carried on for the removal of the ‘ grass-barriers ’ 
(the ‘ Sadd ’), stating that the main constituents of the ‘ Sadd ’ 
are the Papyrus and the ‘ um-soof y ( Vossia procerd) reeds, and 
that the ‘ Ambatch ’ has been unjustly accused of assisting in 
forming the barrier. Possibly Dr. Schweinfurth’s observations 
were not made just where Sir William Garstin investigated 
the composition of the barrier. And Dr. Schweinfurth says 
that in places the ‘ Ambatch * was almost excluded by the 
‘ um-soof.’ Also it is quite conceivable that in some places as 
good a block may be made by Papyrus and Vossia alone 
as by all three plants combined in other places. And the 
objection that the stem of the c Ambatch ’ is too light and brittle 
to withstand great pressure does not seem to have been 
verified by experiment and may not be fatal. The lightness 
and brittleness are admitted ; but would it be possible for 
