NIEBUHR, BARTHOLD GEORG, distinguished historian, born at Copenhagen, son of the succeeding; studied at Kiel, and for a time at London and Edinburgh; after various civil appointments in Denmark, entered the civil service of Prussia in 1806; on the establishment of the university of Berlin in 1810 gave in connection with it a course of lectures on Roman history, by which he established his reputation as a historian, several of the conclusions of which he afterwards confirmed during his residence as ambassador at the Papal Court at Rome from 1816 to 1823; the revolution of the three days of July 1830 in Paris threatening, as he thought, a recurrence of the horrors of the first, gave him such a shock that he sickened of it and died; by his treatment of the history of Rome he introduced a new era in the treatment of history generally, which consisted in expiscating all the fabulous from the story and working on the residuum of authenticated fact, without, however, as would appear, taking due account of the influence of the faith of the people on the fable, and the effect of the latter on the life and destiny of the nation whose history it was his purpose to relate (1776-1830).

NIEBUHR, KARSTEN, a celebrated traveller, born in Hanover; joined a Danish expedition in exploration of Arabia, and alone of the members of it returned home, which he did by way of Persia, Palestine, and Cyprus, and wrote an account of the results of his researches (1733-1815).

NIEL, ADOLPHE, French marshal, born at Muret; entered the Engineers 1825, served in the Algerine War in 1835, before Rome in 1849, at Bomarsund in 1854, at Sebastopol in 1856, as well as at Magenta and Solferino, and finally became Minister of War (1802-1869).

NIEPEE, JOSEPH NICEPHORE, French chemist, born at Chalons-sur-Saone; inventor of photography, the method of effecting which he achieved after long brooding in 1824, and afterwards communicated to Daguerre, with whom he entered into partnership, and who made it known after his death (1765-1833).

NIFLHEIM or MISTHOME, in the Norse mythology the primeval northern region of cold and darkness, in contrast with Muspelheim, or Brighthome, the primeval southern region of warmth and light, the two poles, as it were, of the Norse world.

NIGER, a great river of Western Africa, whose head-waters rise amid the Kong Mountains behind Sierra Leone; flowing NE. as far as Timbuctoo (2 m. from the river), it there bends gradually southward, receives from the E. its great affluent the Benue, and about 100 m. from the coast begins to form a wide forest and jungle-covered delta (larger than that of the Nile), and finally flows into the Gulf of Guinea by 22 mouths after a course of some 2600 m.  Forms, with the Benue, an invaluable highway into the heart of the country; its upper and middle parts, under the names Joliba, &c., are within the French sphere, and the lower portion below Say is under English authority.