MANGANITE

manganite, a mineral consisting of hydrated manganese sesquioxide, mn2o3·h2o, crystallizing in the orthorhombic system and isomorphous with diaspore and gothite. crystals are prismatic and deeply striated parallel to their length; they are often grouped together in bundles. the colour is dark steel-grey to iron-black, and the lustre brilliant and submetallic: the streak is dark reddish-brown. the hardness is 4, and the specific gravity 4.3. there is a perfect cleavage parallel to the brachypinacoid, and less perfect cleavage parallel to the prism faces _m_. twinned crystals are not infrequent. the mineral contains 89.7% of manganese sesquioxide; it dissolves in hydrochloric acid with evolution of chlorine. the best crystallized specimens are those from ilfeld in the harz, where the mineral occurs with calcite and barytes in veins traversing porphyry. crystals have also been found at ilmenau in thuringia, neukirch near schlettstadt in alsace ("newkirkite"), granam near towie in aberdeenshire, upton pyne near exeter and negaunee in michigan. as an ore of manganese it is much less abundant than pyrolusite or psilomelane. the name manganite was given by w. haidinger in 1827: french authors adopt f. s. beudant's name "acerdese," (gr. [greek: akerdes], unprofitable) because the mineral is of little value for bleaching purposes as compared with pyrolusite. (l. j. s.) [illustration] mangbettu (_monbuttu_), a negroid people of central africa living to the south of the niam-niam in the welle district of belgian congo. they number about a million. their country is a table-land at an altitude of 2500 to 2800 ft. despite its abundant animal life, luxuriant vegetation and rich crops of plantain and oil-palm, the mangbettu have been some of the most inveterate cannibals in africa; but since the congo state established posts in the country (c. 1895) considerable efforts have been made to stamp out cannibalism. physically the mangbettu differ greatly from their negro neighbours. they are not so black and their faces are less negroid, many having quite aquiline noses. the beard, too, is fuller than in most negroes. they appear to have imposed their language and customs on the surrounding tribes, the mundu, abisanga, &c. once a considerable power, they have practically disappeared as far as the original stock is concerned; their language and culture, however, remain, maintained by their subjects, with whom they have to a large extent intermixed. the men wear bark cloth, the art of weaving being unknown, the women a simple loin cloth, often not that. both sexes paint the body in elaborate designs. as potters, sculptors, boatbuilders and masons the mangbettu have had few rivals in africa. their huts, with pointed roofs, were not only larger and better built, but were cleaner than those of their neighbours, and some of their more important buildings were of great size and exhibited some skill in architecture. see g. a. schweinfurth, _heart of africa_ (1874); w. junker, _travels in africa_ (1890); g. casati, _ten years in equatoria_ (1891).