What the sailors mean by the Bahr-el-Ghazal is really only the channel as far as they navigate it; to them it is not a stream, in a hydrographical sense, such as either the Bahr-el-Arab or the Bahr-el-Dyoor. It is only at the mouth of the Bahr-el-Arab that there first appears a measurable current, and the fairway, which up to that point is not above 15 feet deep, is subsequently never less than twice that depth. After getting every information I could in the remotest west, I come to the conclusion that the Bahr-el-Arab is the main stream. Even at a distance of 300 miles above its mouth it is found throughout the year as a stream which cannot be forded, but must be crossed in boats, whilst the Bahr-el-Dyoor cannot be traced at all at so great a distance from its union with the Nile. The plains through which the Gazelle flows are too level to allow of any recognition at first sight of the true limits of the territory subject to its inundations. Any one, however, who is familiar with the character of the vegetation of the country, will easily detect symptoms from which he could form a tolerably correct opinion. Accordingly, on my return journey in 1871, I gathered ample evidence to satisfy myself that the Gazelle, associated as it is with the Bahr-el-Arab and the Bahr-el-Dyoor, is a river just as truly as either of the others. The fall of the water in the Gazelle is only produced by the torrent driven from the south and west, and may hardly admit of being estimated, since the entire difference measured between Khartoom and the Meshera (the termination of the navigable course) does not altogether amount to 100 feet. [Sidenote: STREAM OF THE GAZELLE.] An important change in the scenery of the shores supervenes upon a further progress. The lake-like surface of the water gives to the Bahr-el-Ghazal the semblance at first sight of being merely an extensive backwater. That just above the mouth of a stream so considerable as the Bahr-el-Arab there should be this abundance of water at the very time of the year when it is at its lowest ebb, is a circumstance which cannot fail to confirm the supposition which I entertained when I entered the Gazelle: I was certain that the narrow channel through which we travelled in the district of the Nueir could not possibly be the entire river; and there surely must exist to the north of the river other not inconsiderable arms, which are inaccessible on account of the denseness of the river grass.