The tremour of the earth consequent upon portions of its surface being detached, was only felt upon the situation on which it occurred; and were it not for the heavy fall of rocks from the overhanging table-land, no evidences of a violent convulsion could be ever observed; so that I am justified, in attributing to external influences, rather than to internal operations, the occasional agitations of the earth which are experienced in Abyssinia during the wet season. The combined effects, however, of all these disintegrating agents of the table land of Abyssinia, is to increase farther westward the course of the Hawash, and we find that in the situation most favourable for the operation of denudation there is contained, its most distant sources. Already, by the testimony of M. Rochet d’Hericourt and Dr. Krapf, the head of the Hawash reaches within thirty miles of the Abi, the Nile of Bruce, and that in that direction it will still progress, may be safely assumed, whilst the present order of things established by nature is continued; and in the course of time a communication will most certainly be opened between this river and that of Northern Abyssinia, when probably, by this addition to its volume of water, and a continual denudation going on also towards the east, diminishing daily the barrier between it and the sea; the Hawash will then enter the sea, and open a fresh highway into the interior of Africa. Geologists may observe in this mighty operation, something analogous to that to which they attribute other natural phenomena with which they may be familiar, and the facts that I have stated, singular as they may appear, are as easily demonstrated to be true as is the westward progress of the falls of Niagara towards the lakes of Northern America.