But trade routes to the West African coast became increasingly easy, particularly after the French invasion of the Sahel in the 1890s and subsequent construction of railways to the interior.
可是通往西非海岸的貿易路線變得越來越簡易,特別是經過法國 在1890年向西非荒漠草原的侵略及後來非洲內陸鐵路的建築。