They feel certain there is no outlet, because at one time or another they virtually completed the survey of the coast line and listened to native testimony besides.

How the phenomenon of sweet water is to be accounted for we do not pretend to say.

The reader will see further on that Livingstone grapples with the difficulty which this Lake affords, and propounds an exceedingly clever theory.] Tanganyika has encroached on the Ujiji side upwards of a mile, and the bank, which was in the memory of men now living, garden ground, is covered with about two fathoms of water: in this Tanganyika resembles most other rivers in this country, as the Upper Zambesi for instance, which in the Barotse country has been wearing eastwards for the last thirty years: this Lake, or river, has worn eastwards too.
_1st June, 1869._--I am thankful to feel getting strong again, and wish to go down Tanganyika, but cannot get men: two months must elapse ere we can face the long grass and superabundant water in the way to Manyuema.
[Illustration: Lines of Green Scum] The green scum which forms on still water in this country is of vegetable origin--confervae.

When the rains fall they swell the lagoons, and the scum is swept into the Lake; here it is borne along by the current from south to north, and arranged in long lines, which bend from side to side as the water flows, but always N.N.W.or N.N.E., and not driven, as here, by the winds, as plants floating above the level of the water would be.
_7th June, 1869._--It is remarkable that all the Ujiji Arabs who have any opinion on the subject, believe that all the water in the north, and all the water in the south, too, flows into Tanganyika, but where it then goes they have no conjecture.

They assert, as a matter of fact, that Tanganyika, Usige water, and Loanda, are one and the same piece of river.
Thani, on being applied to for men and a canoe to take me down this line of drainage, consented, but let me know that his people would go no further than Uvira, and then return.