[173]A ridge stretches to the south, through the middle of South Africa, and forms an impenetrable barrier between the two coasts. M. Correa de Serra informs me, that the Portugueze in Congo and Angola, have never been able to penetrate to the coast of the Indian ocean.
Mr. Bruce learnt (Vol. iii. p. 668.) that a high chain of mountains from 6° runs southward through the middle of Africa. He supposes the gold of Sofala to be drawn from these mountains. (p. 669.)
[174]Circumstances have shewn, that it declines to the eastward also.
[175]“A wild expanse of lifeless sand and sky!” Thomson.
[176]Page 130.
[177]Water is found at the depth of a few feet, in Fezzan (Afr. Assoc. Q. p. 96: O. p. 146). The same is said by Pliny, concerning this quarter of Africa; lib. v. c. 5. But farther to the NW, on the edge of the Desert, and in the country of Wadreag in particular (Shaw, p. 135.), wells are dug to an amazing depth, and water mixed with fine sand, springs up suddenly, and sometimes fatally to the workmen. The Doctor tells us, that the people call this abyss of sand and water, “the sea below ground.” Exactly the same state of things exists in the country round London, where the sand has in several cases nearly filled up the wells. (See Phil. Trans. for 1797.) The famous well lately dug by Earl Spencer (at Wimbledon), of more than 560 feet in depth, has several hundred feet of sand in it.
[178]Ships that have sailed at a great distance from the African coast, opposite to C. Blanco and C. Bojador, have had their rigging filled with fine sand, when the wind blew strong off shore. The accumulation of the Bissago shoals may have been partly owing to this cause also. They occupy the position where a great eddy of the general southerly current takes place, between C. Verd and Sherbro’.
[179]This quality of the African Desert was familiarly known to Herodotus (Melpom. c. 181, et seq.) He knew also that there was salt in abundance in the northern parts. But as it would appear that the inhabitants in that quarter can furnish themselves with salt of a better quality from the sea, the mines are not wrought.
[180]Some writers have said, that there are gold mines in the neighbourhood of Mina, on the Gold Coast; others, that the gold is rolled down by the rivers to that neighbourhood. Both may be true.
It is difficult to conceive any other adequate cause, than the exchange of the gold of the inland countries, for the introduction of so vast a quantity of kowry shells, which are carried from Europe to the Coast of Guinea, and pass for small money in the countries along the Niger, from Bambara to Kassina, both inclusive.