Indeed this region south of the Tripolitaine, from Fezzan across the Tibesti mountains and the eastern Sahara to Lake Chad, had become the domain of another remarkable negroid race which has had much to do with the opening up and the closing of negro Africa, the Tibu or Teda. Physically they are an exact hybrid between Hamite and negro, and resemble very much the more negro-like types of Somali; but their language, which is cognate with the Kanuri of Bornu, a kingdom first semi-civilized by the Tibu, offers no indications of affinity with other African forms of speech; like Songhai it is (so far as our existing knowledge goes) quite isolated. The Tibu had much to do with the introduction of iron weapons and implements and iron-working into negro Africa. They seem to have reproduced the boomerang or throwing-stick in iron, and thus to have originated those wonderful throwing-knives which attained their highest development in the north-central basin of the Congo. A notable stream of Tibu culture (no doubt largely derived from ancient Egypt) entered Congoland about 1500 to 2000 years ago, finding its way up the Shari from Lake Chad, across the Mubangi and main Congo, and so down into the Bushongo country of central Congoland. The old Bushongo language (now extinct) was not a Bantu speech, but an unclassified tongue with relationships to the forms of speech still current on the Upper Shari. Other civilizing negroid immigrants, Tibu or Hamite in origin, appear to have drifted from the north-east into the Bahr-al-Ghazal region and thence into N.E. Congoland, where by mixture with the negroes they formed the remarkable Nyamnyam and Mañbettu peoples, or at any rate the aristocracies of those tribes. Farther east still we have the remarkable Hima aristocracies of cattle-keeping semi-nomads, very like the Fula in appearance and customs, but always speaking pure Bantu languages. They would seem to have been derived from an ancient Egyptian or Gala origin.