It was on the fifth day of our journey, when we had travelled, so far as we could reckon, about one hundred and thirty-five to a hundred and forty miles westwards from the coast, that the first event of any real importance occurred.  On that morning the usual wind failed us about eleven o’clock, and after pulling a little way we were forced to halt, more or less exhausted, at what appeared to be the junction of our stream with another of a uniform width of about fifty feet.  Some trees grew near at hand—­the only trees in all this country were along the banks of the river, and under these we rested, and then, the land being fairly dry just here, walked a little way along the edge of the river to prospect, and shoot a few waterfowl for food.  Before we had gone fifty yards we perceived that all hopes of getting further up the stream in the whale-boat were at an end, for not two hundred yards above where we had stopped were a succession of shallows and mudbanks, with not six inches of water over them.  It was a watery cul de sac.

Turning back, we walked some way along the banks of the other river, and soon came to the conclusion, from various indications, that it was not a river at all, but an ancient canal, like the one which is to be seen above Mombasa, on the Zanzibar coast, connecting the Tana River with the Ozy, in such a way as to enable the shipping coming down the Tana to cross to the Ozy, and reach the sea by it, and thus avoid the very dangerous bar that blocks the mouth of the Tana.  The canal before us had evidently been dug out by man at some remote period of the world’s history, and the results of his digging still remained in the shape of the raised banks that had no doubt once formed towing-paths.  Except here and there, where they had been hollowed out by the water or fallen in, these banks of stiff binding clay were at a uniform distance from each other, and the depth of the stream also appeared to be uniform.  Current there was little or none, and, as a consequence, the surface of the canal was choked with vegetable growth, intersected by little paths of clear water, made, I suppose, by the constant passage of waterfowl, iguanas, and other vermin.  Now, as it was evident that we could not proceed up the river, it became equally evident that we must either try the canal or else return to the sea.  We could not stop where we were, to be baked by the sun and eaten up by the mosquitoes, till we died of fever in that dreary marsh.

“Well, I suppose that we must try it,” I said; and the others assented in their various ways—­Leo, as though it were the best joke in the world; Job, in respectful disgust; and Mahomed, with an invocation to the Prophet, and a comprehensive curse upon all unbelievers and their ways of thought and travel.