Abstract

After alluding to certain observations of Cameron, Livingstone, and Stanley on the changes of level of Lake Tanganyika, the writer states that the most interesting point in connexion with the rise and fall of the lake is the question:—How is it possible for a great lake to rise 30 feet above its normal level by the blocking up of its outlet?

This is to a large extent accounted for by Cameron. He says: “On going down the river [Lukuga] we found that it was blocked by vegetation similar to that on which we had crossed the Sindi, and also to that over which we had had to pass to reach the shore from our boats at the southern end of Lake Tanganyika, and which I afterwards found existed on Lakes Kassali and Mohrya. The presence of this mass of vegetation is easily accounted for. Every day that there is a gale of wind, and the consequent sea on the lake, blocks of this peculiar growth are detached, and such as survive the passage to the outlet getting jammed together commence to grow, and form a sort of porous stopper in the neck of the outlet.” He then quotes Sir Samuel Baker's experience on the Nile when the whole channel “was blocked up and the expedition to Gondokoro impeded for a year, the country above the stoppage having been converted into a series of swamps and shallow lakes, while Egypt was suffering from all the evils of a low Nile.”

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