[Footnote 58: The Thames, between Maidenhead Bridge and Mortlake, (about 41 B. miles in a straight line,) has a fall of rather more than one foot eight inches in each mile. But this is a _smooth_ part of its course: for although the Thames does not, by any means, spring from very elevated lands, it cannot be supposed to fall less than four feet in each mile, taken on its whole course. On this idea, the Niger should have a fall of more than 8000 feet, in its supposed course to the White River. But even if two feet and a half (which appears very moderate indeed) be allowed, the fall would be no less than 5625 feet, or 115 yards more than an English mile. Is it to be credited, that the bed of the White River, on the south of Darfoor, and at a point not very remote from its source, is a mile lower than the springs of the Joliba, or Niger?] [Footnote 59: Browne’s Travels, page 473.] [Footnote 60: Edrisi says, “Ab urbe Ghana ad primos limites terræ Vancáræ est iter octo dierum (orientem versus)—Atque hæc eadem est insula longitudinis trecentorum milliarium, centum et quinquaginta latitudinis, quam Nilus undequaque circundat toto anni tempore. Adveniente verò mense Augusto, et æstu gravescente, Niloque inundante, insula ista vel certè major pars illius aquis obruitur, manetque sepulta aquis quamdiu Nilus terram inundare consuevit.” (Sionita, p. 11 and 12. See also Hartmann’s Edrisi, article Vankara, p. 47 _et seq._] [Footnote 61: Ebn Haukal, an Arabian geographer, of the tenth century, (lately translated by Sir William Ouseley,) gives the following account of the river _Heermend_, p. 205. “The most considerable river of _Sejestan_ is the _Heermend_, which comes from Ghaur to the city of _Bost_, and from that runs to _Sejestan_, to the lake _Zareh_. This lake is very small when the waters of the river are not copious; when the river is full, the lake increases accordingly. The length of this lake is about 30 farsangs, (about 110 B. miles,) and in breadth about one _merhilch_. (Day’s journey, or 24 B. miles.) Its waters are sweet, wholesome, &c.” It is well known, that there is no _outlet_ from the lake Zareh.] [Footnote 62: Begama of Edrisi.] [Footnote 63: Mr. Browne, (page 473,) states the distance between _Donga_, and the (_southern_) limit of Bornu, to be 20 journies.] [Footnote 64: Mr. Horneman’s informant called it _Ungara_; and it appears that the Arabs name it _Belad-el-Tebr_, or the country of gold. (Herbelot and Bakui.) Mr. Browne was told, in Darfoor, that gold was not found in any quantity, to the west. But Wangara, a country of gold, at least in former times, lies to the west of Darfoor!]