MAM 



[277] 



MAN 



abundant. There are two large 

 islands near the mouth of the river 

 Indigerska, which are said to be 

 entirely composed of bones of the 

 mammoth, intermixed with ice and 

 sand. Remains of the mammoth 

 have been found from Spain to the 

 coasts of Siberia, and throughout 

 all North America. 



The grinders of the mammoth 

 are formed of two substances only ; 

 an internal bony substance, and a 

 thick covering of enamel. The 

 form of their crown is generally 

 rectangular, the crown being divided 

 by spreading grooves into a certain 

 number of transverse risings, each 

 of which is divided, in the contrary 

 direction, into two large obtuse, 

 and somewhat quadrangular and 

 pyramidical points ; the whole 

 crown, when not worn, being beset 

 with large points, arranged in pairs. 

 In consequence of several of these 

 teeth being much worn down, not 

 only to the base of the pyramids, 

 but even so low as only to leave one 

 square surface edged with enamel, 

 it has been concluded that they were 

 used in the trituration of vegetable 

 food. M. Cuvier particularizes 

 three sorts of these grinders; nearly 

 square, with three pairs of points, 

 generally much worn ; rectangular, 

 with eight points, less worn ; and 

 others with five pairs of points, and 

 a single smaller one, scarcely the 

 least worn. Cuvier considered 

 he had distinguished five different 

 species. 



MANA'TTJS. A genus of herbivorous 

 cetacea, placed by Cuvier in the 

 family Cetacea herbivora. The 

 manatus appears to have inhabited 

 the seas of our latitude during the 

 Miocene and Pliocene periods. The 

 recent species are now found near 

 the coasts and mouths of rivers, in 

 the torrid zone. They have an 

 oblong body, terminated by an 

 elongated oval fin : the grinders 

 have a square crown, marked with 



two transverse elevations; they 

 are eight in number throughout. 

 Lamantin, a name often given to 

 manatus, is said to be merely a 

 corruption of Manatus. 



MA'NDIBLE. (mandibulum, Lat. ajaw.) 

 In insects, the upper jaws are called 

 mandibles; the under jaws, maxillae. 

 The mandibles of insects are two 

 strong, corneous, somewhat bent 

 hooks, the inner margin being more 

 or less dentate ; they articulate with 

 the cheeks at their broad basis, move 

 by ginglymus, and are opposed to 

 each other like the blades of scissors. 



MAKDI'BULAB. Pertaining to the 

 jaw. 



MANQANE'SE. (manganese, Fr. manga- 

 nese, It.) A metal but little known 

 in its pure or metallic state, to 

 which it is reduced with much 

 difficulty, in consequence of its 

 great affinity for oxygen. It was 

 first obtained in a metallic form by 

 Gahn, from the black oxide of 

 manganese, a substance first in- 

 vestigated by Scheele. When pure, 

 it has a grayish- white colour, with 

 some lustre. Its texture is granu- 

 lar; hardness, nearly that of iron. 

 Specific gravity from 7'0 to 8'0. 

 It has little or no malleability, and 

 is difficult of fusion. It absorbs 

 oxygen by exposure to the atmos- 

 phere, and its melting point is 

 about 160 "W. 



In its metallic state, manganese 

 is not applied to any use. It is 

 obtainable in small quantities from 

 the black oxide by heating it in an 

 intense furnace, with charcoal and 

 a little oil. 



The common ore of manganese 

 is the black, or peroxide, a valuable 

 substance to chemists, as that from 

 which oxygen is most easily ob- 

 tained ; it consists of 27'7 manga- 

 nese, and 16 oxygen. When added 

 in small quantities to glass, it 

 removes the greenish or yellowish 

 tinge which arises from iron or 

 other impurities ; but if added in 



