In effect, then, the general course of the Nile below Sennar lies to the west of north, instead of the contrary, as described in the imperfect materials offered to M. D’Anville. For we cannot doubt the general truth of Mr. Bruce’s geographical positions, although we may not be inclined to allow them every point of accuracy. In the observation of longitude at Kosire, we have seen that he comes very near to Capt. White: and his longitude of Cairo, is more exact, or more in harmony with Capt. White’s observations at Suez, than the longitude recorded in the Con. de Temps. We have moreover another observation of longitude taken by Mr. Bruce at the eastern source of the Nile, 36° 55′ 30″, (lat. 10° 59′), from whence one route leads eastward to the shore of the Red Sea at Masua, another westward to Sennar. Admitting his observations to be ever so coarsely made, these routes must have afforded so considerable a check, to the distance between Masua and Sennar, as to have precluded any very great error, in a difference of longitude of about six degrees only; so that there is little question but that M. D’Anville’s statement is wrong.
From Sennar, Mr. Bruce has a new and interesting route, northward to Syene. Dongola lay wide to the west of this route; and he has not informed us on what authority it is placed in his map. Still, however, the change in the position of the Nile, must carry Dongola to the eastward with it, of course; and in Bruce’s map it is found at 1° 18′ diff. long. to the east of D’Anville’s;[94] equal to 73 G. miles. The latitude of Dongola is also ½ a degree to the south of the parallel assigned by D’Anville, that is, 19½ instead of 20°. With respect to that of Sennar, D’Anville was right.
In describing the western head of the Nile (and which has no existence in Mr. Bruce’s map), it may be thought that I have advanced into the regions of conjecture; but I trust that I have not gone beyond the limits implied by the authorities. To enter into a detail of these, together with the deductions and combinations arising from them, would occupy too much room here; especially as they are designed for another place. It may be sufficient to state, that the branch in question, called the White River, or Abiad,[95] is admitted by Mr. Bruce himself, to be a more bulky stream than the Abyssinian branch. That M. Maillet was told, that it holds a course which is distant from 12 to 20 journies from the eastern branch. That Ledyard was told at Cairo, by certain persons from Darfoor, that the Nile has its fountains in their country situated 55 journies to the westward of Sennar:[96] and whose frontier province, Kordofan, is placed by Bruce, adjoining to the west of the country of Sennar. And finally, that Ptolemy, Edrisi, and Abulfeda, all place the head of the Nile in a quarter far remote from Abyssinia. Ptolemy, in particular, has described the eastern source, in such a way, as that it cannot be taken for any other than the Abyssinian branch (i.e. Bruce’s Nile); and yet he at the same time describes a larger, and more distant, source, to proceed from the SW; answering to the White River. His Coloe lake, is clearly the Tzana of Bruce: and may possibly have been meant to express Galla, the name of the southern division of Abyssinia.[97]
Having completed this part of the subject, I proceed to the inland positions in the western and central parts of the continent.
M. D’Anville has been followed in the geography of Barbary and Morocco, with the exception of an adjustment of the interior of the latter, to the coasts; which are drawn from the charts in the atlas of Don Tofino, in which the capes of Cantin, Geer, &c. are placed more to the east, in respect of the strait, than in D’Anville.
The lower parts of the Senegal, Gambia, and Rio Grande, are from M. D’Anville’s, and Dr. Wadstrom’s maps.
Of Mr. Park’s route and discoveries, it is needless to say more, than that the particular map which contains them, has been copied into this; forming a most important member of it.
The routes and positions formerly introduced from materials collected by the African Association, in the northern part of the continent, are revised and reconstructed; perhaps with more effect, as our knowledge and experience of the subject increases.
Fezzan is placed, as before, due south from Mesurata: its capital Mourzouk, being 17½ journies of the caravan, distant. Edrisi affords a slight check to the bearing, as well as to the distance, by means of Wadan, which lies nearly midway, and is five journies west of Sort, a known position on the coast: and also eight journies of his scale from Zuela, a known position in Fezzan,[98]
A description of the caravan routes from Tripoly, to Mourzouk, Egypt, and the Niger, will be found in the Proceedings of the Association, published in 1790, and 1791 (chapters x. and xii.)