Ubangi

UBANGI, a river of equatorial Africa (extreme length 1,400 m.), the chief northern affluent of the Congo (q.v.). The Ubangi (otherwise Mubangi or Mobangi) enters the Congo by various mouths between o° 2 2' and o° 3 7' S. and 17° 4o' and 17° 5o' E. The Ubangi is formed by the junction of the Bomu and the Uele (Welle), the latter rising a few miles from the western edge of the western rift-valley, north of Lake Albert and after a course of 700 m. it joins the Bomu at Yakoma. Both streams, which have hitherto received numerous affluents, flow westward as a wide river. A short distance below the junction of the Bomu and Uele, the Kota coming from the borders of Darfur, and forming the most northerly extension of the Congo basin enters the united stream (right). The remaining tributaries, mostly on the right bank are smaller. Below the confluence with the Kouma, which river offers water communication to within easy reach of the Shari basin, the Ubangi makes a great bend south and immedi ately it flows between hills and passes the Zongo or Grenfell rapids, which are a barrier to navigation save for small boats in flood season. Above Zongo rapids the river is navigable up to the confluence of the Uele and Bomu, and the former is navigable at high flood up to the Bomokandi confluence in 26° 8'.

The Uele was discovered from the north by G. A. Schweinfurth in 187o, who believed it to belong to the Chad system, but W.

Junker, who (1882-1883) followed the river to near its con fluence with the Bomu, showed that it belonged to the Congo system. In 1885 George Grenfell, ascended the Ubangi as far as the Zongo rapids. He was followed in 1886-1889 by the Bel gian, A. van Gele, who established the identity of the Ubangi with Schweinfurth's Uele. The Bomu was discovered from the

north in 1877 by a Greek, P. Potagos, and its upper course was followed for some distance by Junker. The Ubangi and the Bomu form the frontier between Belgian Congo and French Congo, the northern banks of both streams belonging to France.

f.TBERWEG, FRIEDRICH

German historian of philosophy, was born on Jan. 22, 1826 at Leichlingen, in Rhenish Prussia, where his father was Lutheran pastor. Educated at Gottingen and Berlin, he qualified himself at Bonn as Privat dozent in philosophy (1852). In 1862 he was called to Konigs berg as extraordinary professor, and in 1868 was advanced to the ordinary grade. He died on June 9, 1871. His compendious, ac curate and impartial History of Philosophy has been repeatedly re-edited. At first he followed Beneke's empiricism, and opposed the subjectivistic tendency of the Kantian system, maintaining in particular the objectivity of space and time, which involved him in a somewhat violent controversy. His own system he preferred later to describe as an ideal realism, which refused to reduce reality to thought, but asserted a parallelism between the forms of existence and the forms of knowledge.

tYberweg's works include System der Logik ; 5th ed., 1882; Eng. trans. of 3rd ed. by T. M. Lindsay, 1871) ; Grundriss der Gesch. der Phil. (1863-66, 12th ed. 5923-28) ; an essay (1861) on the authen ticity and order of Plato's writings; Schiller als. Hist. and Phil. (pub lished by Brasch from his papers, Leipzig, 1884). See F. A. Lange, F. Ueberweg (1871) ; M. Brasch, Die Welt- and Lebensanschauung F. Ueberwegs (Leipzig, 1889).