THE SOUDANESE STATES 79 kingdoms from the seventh to the seventeenth century, at which latter period the whole underwent a chaotic change, it is to be observed that the tide of progress spreads steadily from the West eastward, not from the East westward. In saying this I allude especially to those countries to the west of Lake Chad, which, taken collectively, may be said to form the Western Soudan. There is one other general observation which it is, I think, interesting to make with regard to the civilising influence exercised by the Empire of the Two Shores upon Negroland. It is that between the seventh and the seventeenth centuries, though there were many local wars and conquests of black kingdoms by Berbers and Berber kingdoms by blacks, there was never any military conquest made or attempted by Spanish Arabs of the black countries with which they traded. At the beginning of the seventeenth century, when the Spanish Arabs had themselves been expelled from Europe, this policy was reversed with disastrous results, and the conquest of the country by the decadent Moors put an end to the prosperity of Negroland.

In order to follow with any interest the historic development of this little known portion of the world, it is well to glance at a map of Africa and note the more salient physical features which have to some extent determined here, as they determine elsewhere, the political distribution of the country. It has already been mentioned that the latitude of 17° N. may be taken as the edge of the summer rains, and that between 10° and 17° all the finest races of this part of Africa are to be found.

This is M. de Lauture's limit of distribution. Later experience would lead us perhaps to draw the southern line a little lower. Probably the parallel of 9° would be found more accurate. If two blue pencil lines be drawn upon these parallels on a map of north-west Africa, it will be seen that they include within their limits the whole course of the Senegal from its rise in the mountains north of Sierra Leone to its mouth in the Atlantic Ocean,