Lastly, it is elsewhere expressly said, that Sego is five days west of Jenné; the new map gives W. ¼ S. W. All these data, it is plain, perfectly coincide; and although they are not authenticated by a single good celestial observation, yet they agree too well together to allow one to venture upon deranging the whole itinerary of our traveller, and carrying the city of Sego and with it the whole course of the river, two or three degrees farther east, when besides there exists no observation whatever, either geographical or astronomical, for carrying the river and its towns farther into the interior of the continent.
The position of Djenné, the arms of the river by which it is surrounded, its situation in a large island apart from the Dhioliba, the stream which branches off in the neighbourhood of Sego, and rejoins the river at Isaca, four days further on, are so many circumstances all equally new, and which tend greatly to modify our previous notions. Looking at this complication of details, the obscurity and contradictions contained in all the accounts of the negroes on the subject of Djenné may be easily conceived; but, upon an attentive study and careful comparison of the different data, we arrive at a tolerably just idea of these localities: the reader will judge whether I have attained this object in the course of these observations and in the drawing here submitted to him. Unquestionably, there yet remain many circumstances to be learnt relating to this double branch of the Dhioliba, the true form and actual extent of the island of Djenné, and its double or perhaps triple communication with the branches of the river; for every step yet gained in our acquaintance with this mysterious river seems to throw us to a greater distance from the ultimate object: it is, therefore, to confess the truth, nothing more than a slight sketch that I have presumed to delineate; time will rectify our yet imperfect notions, and complete the observations of our indefatigable traveller, when the use that I have made of them may be judged of. M. Caillié presumes the island of Djenné to be eighteen miles in circumference; but the construction of the route and the general appearance of the map induce me to believe that it is of greater extent: I also suspect, that the junction of the island with the western branch of the river cannot be seen from Djenné, but only its junction with the eastern branch; this would be a natural consequence of the westerly situation of Sego, with regard to Djenné. For the rest, I refer to the observations in the following article, that this discussion may not be prolonged here.
I shall not stay to inquire how it happened that Mungo Park knew nothing of a second branch of the river, when he proceeded from Sego to Silla. I shall likewise abstain from entering into further developments respecting the course of the Dhioliba beyond Djenné. The narrative furnishes ample details, not less instructive than new, respecting the course of the river, its depth, its immense width in some parts, to the extent of half or even a whole mile. One of the most interesting points of this route by water is the great lake Debo, or Dhiebou, which M. Caillié met with half-way between Djenné and Timbuctoo. I cannot help thinking that this lake is the same which figures on the maps under the name of Dibbie, but with a widely different position, form, and extent.
The enthusiasm of our traveller at the sight of this sea of fresh water must appear excusable to every one, and his eagerness to take possession, in a manner, of the spot, on behalf of his country, by giving names to three islets situated in it, cannot but be generally approved. Twenty three years earlier, Mungo Park had accomplished this same navigation, perhaps, had also given names to these little mediterranean isles. Who, either in France or in England would have blamed him for this national feeling, had the account of his discovery reached Europe?.
The lake has two divisions, one eastern, the limits of which may be seen, the other western, extending beyond the reach of sight. M. Caillié is ignorant whence this mass of water proceeds; is it from a tributary, or is it, on the contrary an efflux from the inundations of the Dhioliba? This geographical question, on many accounts an important problem, remains then in obscurity; further on I shall offer a rather probable opinion[63].
To the east of this lake are sands and sterile hills; to the west, it is lost in vast marshes; the navigation of the latter division must be extremely difficult. Passing from Djenné to Timbuctoo, the traveller navigates the eastern division of the lake, keeping close to the right bank.
Below the lake (on the map) a winding of the river will be observed, which perhaps appears forced and unnatural; it results from the lines of route as noted down and the difficulty of substituting any thing else has alone determined me to retain it, although doubtful of its accuracy: an error, however, in this tracing will have little influence on the general result.
In approaching Cabra, the port of Timbuctoo, M. Caillié perceived to the right a large arm of the river, running E. N. E. and he continued to navigate the other, holding a north-west course. He was informed that the latter rejoined the first at some distance; but this important fact has not been verified by any European eye; the traveller could not have ascertained it, without repairing himself, at considerable risk, to the point of junction. As for the inhabitants, perfectly indifferent as to obtaining or transmitting intelligence of this sort, they spoke very vaguely to him on the subject. The problem, therefore, of the ulterior direction, and of the final termination of these branches of the river, is yet to be resolved; I defer this discussion to a subsequent article[64], as well as the particular question of the situation of Timbuctoo[65]; and shall conclude this with repeating, that the itinerary from Timé to Galia, and from Galia to Timbuctoo, has been framed on the calculation of two miles an hour.
THIRD PART OF THE TRAVELS.
The progress of M. Caillié through the desert has also been estimated at two miles an hour, at least as far as Tafilet, and that for reasons explained at the beginning. The principal interest presented by this part of the route consists in the exact information it contains of the wells and stations to be met with amidst this ocean of sand. Science is indebted to M. Caillié for numerous and correct notions of these vast solitudes, which travellers cannot confront without consternation. Thus, we knew the spot called el-Araouan only by the wells found there, as a place at which the caravans usually fill their water-skins; but our traveller informs us that it is an important town: seeing it thus surrounded on all sides by the deserts, we are the less surprized at the situation of Timbuctoo in the midst of the sands.