The Construction of the Geography continued.
At Silla, Mr. Park was informed that Tombuctoo was yet fourteen journies of the caravan distant from him; and these he has calculated at 200 G. miles only, in a direct line from Silla; as it appears that a bend in the course of the river, prevents a direct line of route towards it. As to the bearing, he unfortunately could not, as at Jarra, obtain a consistent account of it. The natives always pointed along the general course of the river; although, as it may be supposed, it occasionally deviated to the right and left. It has been seen, in the bearing of Sego, how nearly it was given by judgment; but then the two cases differ very widely. The route is entirely by land, from Jarra to Sego, by which the idea of the general line of direction is better preserved, than when broken into so many small parts, by a river navigation, the more ordinary mode of communication (as it appears) between Silla and Tombuctoo. There were, no doubt, people, could Mr. Park have been able to meet with them, who having made the journey by land, could have furnished him with better information: but the reader, who already knows under what suspicious circumstances Mr. Park travelled in this quarter, will easily conceive that he was precluded from any communication with those, who alone could have given the information: that is, the Moorish merchants, and their dependants.
The bearing of Tombuctoo from Benowm, was pointed out to Mr. Park, by a merchant of some consideration, who had resided at Walet, and had visited both Tombuctoo and Houssa. But the exceeding great distance of Tombuctoo and Benowm, (it being nearly twice the distance of Sego from Jarra), will not admit such a degree of confidence in the report, as to allow it to supersede all other authorities, however it may aid the task of approximating the position. But, notwithstanding, it will appear, that on the whole, it coincides most wonderfully with the other data.
The bearing in question, pointed out at different times, was commonly E by S, by compass: and Mr. Park never found his informant vary more than half a point, which was to the southward; or E by S ½ S. But the idea left on his mind, was E by S; which, allowing 17 degrees variation, is about east half north; or more correctly, E 5¾ N. And hence, admitting the distance of 200 G. miles between Silla and Tombuctoo, which supposes a space of about 500 such miles between Benowm and Tombuctoo, this latter would fall at about 50 minutes of latitude northward from Benowm (whose parallel is the same with that of Jarra, 15° 5′), and consequently in 15° 55′. The obliquity of the intermediate meridians, might increase the parallel some minutes, and we may call it roundly 16°.
Such then was the received opinion at Benowm, concerning the parallel of Tombuctoo: for, it will appear, that the distance on the Rhumb, which determines the difference of latitude, cannot be taken lower, than has been stated.
If the general course of the Joliba, after its escape from the mountains, may be admitted to have any weight in the determination of the question (since Mr. Park says, that they always pointed along it, to express the line of direction, in which Tombuctoo lay), this will point to a higher parallel, by about half a degree, than the bearing from Benowm; that is to 16½ degrees. And, it may be remarked, that the difference between these results falls yet short of what would have arisen on an error of 5 degrees in the bearing; such as was experienced in that of Sego from Jarra.
Mr. Park was informed whilst at Benowm, that Walet, the capital of Beeroo, was ten journies distant, and this latter eleven journies short of Tombuctoo. According to Mr. Park’s information, Walet stands at about 240 G. miles, to the eastward of Benowm; (which would require no less than 24 such miles per day, and appears out of rule, unless meant for journies of couriers, which is possible enough.) But what is most to our point, is, that by the information he received, concerning the position of Walet, it appears to lie from Benowm, in the same line of direction which points to Tombuctoo, when placed in 16½. Now, as Walet lies in the shortest route from Benowm to Tombuctoo, one might infer, of course, that it lies also the nearest to the line of direction towards Tombuctoo, of any of the places pointed out: and, I confess, I am strongly inclined to adopt the highest parallel, on this very account.
These alone, are the authorities for the position of Tombuctoo, derived from Mr. Park’s observations and inquiries; and which differ, as we have seen, no more than half a degree in the parallel: that is, from 16°, to 16°½. The reader may recollect, that these are very far indeed to the southward of those assigned to it, by M. D’Anville and myself, in former publications; as we mistook its position so far, as to place it between 19°, and 20°.
Before I proceed to state the authorities for its position, derived from the northern stations, it will be proper to compare the calculation of distance made by Mr. Park, with the reports of merchants and travellers; in order finally to deduce the longitude of Tombuctoo from the west; and afford a fair ground of comparison, between the authorities from the opposite quarters.
It has appeared that Sego, according to Mr. Park’s calculation, falls in latitude 14° 10′, longitude 2° 1′ west of Greenwich: and accordingly, the direct distance between it and Medina, the capital of Woolli, will be by this account 618 G. miles. Now, the merchants reckon 36 journies between them. The daily rate between Fezzan and Egypt having come out by construction 16,3[78] per day, on 53 days, and about 16¼ between Morocco and Jarra, on 50 days, I may venture to assume the highest of the two rates on 36 days; and this gives about 587, or only 31 short of Mr. Park’s result.