912 LIFE OF DA VID LIVINGSTONE, LL.D 



" This Mitwansi is a tract of alluvial deposit, and is the result of the united 

 action of the lake winds (which from the end of April to the middle of Novem- 

 ber prevail from the south-east) and the feeble current of the former affluent 

 Lukuga. The current, as may be expected from the very limited area it 

 drained, was met daily during nearly seven months of the year by the waves 

 of the lake, which encroached yearly nearer and nearer to its source, and the 

 detrital matter which would have been borne into the lake by a stream of 

 greater force was deposited amid the papyrus. This plant flourishes in still 

 and sweet-water lagoons or in quiet bends of rivers, and once it has thoroughly 

 obtained root it becomes almost as immovable as a forest. As the waters of 

 the lake advanced with its annual rise they destroyed with each year some 

 small portion of the force of the Lukuga current ; and the water plants and 

 other organic debris floating down the stream no sooner felt the influence of 

 the lake wind than they were heaped up amid these papyri ; other matter 

 borne direct from the lake, such as floating canewood, and earthy washings 

 from the banks and the bar, were pressed against them, sometimes thrown 

 amongst them. Soil, sand, decomposing vegetation, sunk on the surface, bore 

 it down with their weight, and thus the process of entombing the earlier 

 debris created finally a tract of clayey mud and ooze, out of which a luxuriant 

 growth of papyrus shot its brush-like heads as dense as a field of corn. 



" While the Lukuga was a river it will be seen that there was a constant 

 precipitation of detrital matter, and as steady an accumulation of it in one 

 locality, until the river became annihilated, and only its bed, now filled by 

 the creek, and the small tributary streams, mark its former course. 



" Since the Tanganyika has risen to the level of the Mitwansi — whether 

 this year, last year, or two years ago, matters not much which — a change 

 must be looked for, and with the advance of time it will become more decided 

 and remarkable. The mud and ooze, with all the papyrus of the Mitwansi, 

 furnishes too feeble an obstacle to resist the increasing volume received each 

 year by the Tanganyika, while there is a steep slope at the western side of 

 it r^ady to pour away the surplus water. The consequence will be that five 

 years hence, perhaps a little later, an effluent willbe formed ofgreat magnitude 

 and real force, for the fiat of Nature has gone forth to the Tanganyika, ' Thus 

 high shalt thou rise, and no higher.' 



" In these results, patiently and impartially attained, I see no opposition 

 to Lieutenant Cameron's claiming the full honour of the discovery, but rather 

 a simple reconciliation of apparently opposing statements. The whole was a 

 perplexing riddle to me, which the more I thought of the more complicated 

 it grew, and only a personal examination of the scene would ever have enabled 

 me to understand the matter. 



" In the absence of a scientific geologist I must take upon myself to sug- 

 gest a few thoughts to those of your readers who may become interested in this 



