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MOLYBDENUM 



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MOMP02 



.|rn-.-l\ rlustri, ,| iii many \sli"i I 

 ii..iin.l i In- erect stem, and are ttin- 

 ..iil.ir in (Init the white tnl.nl. u 

 i-fi-nll:i (of the type common in 

 l.il.iutrs liko the dead-nettles) is 

 mil smaller than the calyx. 

 which nil-loses it like a hood. 



Molybdenum (Gr. molybdoa, 

 lead). One of the metallic elements, 

 hniiical symbol, Mo ; atomic 

 wright, 96 ; specific gravity, 8'6 ; 

 in. It ing-point about 1,900 C. 

 F.). Silver white in 

 colour, with a strong metallic 

 lustn-. it is prepared by heating the 

 chloride or the trioxide to redness 

 in a current of hydrogen. The prin- 

 cipal ores of the metal are molyb- 

 i I'n it r, a sulphide containing 59 

 ji.r. .Mo and 41 p.c. sulphur, found 

 in granite, gneiss, mica slate, and 

 allied rocks, and in granular lime- 

 .-ti'iir; and lead molybdate, in 

 svliii h it is present in the form of 

 molybdic acid, combined with lead 

 oxide. It appears also in one or two 

 other rare minerals. 



While a rare metal, it is widely 

 distributed, occurring in Canada, 

 the U.S.A., Bolivia, Peru, Chile, 

 Queensland, New South Wales, 

 Tasmania, New Zealand, Japan, 

 Rhodesia, East Africa, Sweden, 

 Germany, and Norway.and in Corn- 

 wall and Cumberland. Molyb- 

 denum sulphide appears to have 

 been first recognized in 1778 by C. 

 Scheele ; and was first isolated by 

 the Danish chemist P. J. Hjelm in 

 1782. It is in considerable demand 

 for use in the preparation of alloy 

 tool steel, either in the form of 

 nearly pure metal or as ferro- 

 molybdenum, this latter prepara- 

 tion containing from 50 p.c. to 85 

 p.c. of Mo and from 50 p.c. to 10 

 p.c. of iron, with traces of silicon, 

 phosphorus, and sulphur. The 

 alloy is mode in the electric fur- 

 nace. See Metallurgy ; Steel. 



Mombasa. Chief port of Kenya 

 Colony, E. Africa. Situated on a 

 coral island connected with the 

 mainland by rly., it has two har- 

 bours, that on the N.E. being 

 mainly used by small steamers and 

 native craft. The Kilindini har- 

 bour, used by large vessels, is one of 

 the finest natural harbours on the 

 E. coast of Africa. Here is the 

 coastal terminus of the Uganda 

 Rly. Mombasa was at one time the 

 capital of the Portuguese empire in 

 E. Africa. The massive fortress 

 erected 1593-95 sustained a pro- 

 longed siege in 1696-97 and is the 

 most prominent building in the 

 city. Mombasa was held by the 

 sultan of Zanzibar from 1834-88. 

 There are an Anglican cathedral 

 and a R.C. church. Pop. 30,000. 



Moment. Term used in mathe- 

 matics in various ways. The mo- 

 ment of a force about a point is the 



product of that force by the per- 

 p. mlii-uliir distance of the point 

 1 1 "u i tin- line of action of tin 

 The sum of the moments of two 

 forces about a point is the same a* 

 the moment of their resultant 

 about the point. The moment of 

 inertia of a rigid body about any 

 axis is the summation of the pro- 

 ducts of the masses of the particles 

 of the body and the squares of their 

 distances from that axis. The 

 bending moment at any section of a 

 beam is the algebraic sum of the 

 moments of all applied forces, in- - 

 eluding the reactions, on either side 

 of the section, and is usually writ- 

 ten B.M. or M. The word is also 

 used in phrases denoting a short 

 period of time. 



Momentum. In dynamics, the 

 product of the mass of a moving 

 body and its linear velocity. The 

 term was used by Galileo and New- 

 ton, and by the latter's third law of 

 motion the momentum of a body or 

 a system of bodies cannot be 

 changed by the actions of forces 

 between their various parts. This 

 is the principle of the conservation 

 of momentum. The angular mo- 

 mentum of a body is a term used in 

 connexion with rotating bodies, 

 and is the product of the moment 

 of inertia of the body about the 

 axis of rotation and its angular 

 velocity. See Dynamics ; Force. 



Mommsen, THEODOR (1817- 

 1903). German historian and 

 scholar. He was born at Garding 

 in Slesvig, Nov. 30, 1817, the son 

 of a pastor, and educated at Kiel 

 University. Specialising in the 

 study of antiquities, he spent three 

 years in Italy studying inscriptions. 

 The results of his work brought 

 him wide recognition, and in 1848 

 he was appointed professor of 



Theodor Mom mien, 

 German historian 



Mombasa, Kenya Colony. Landing place 

 lor small steamers and native craft 



civil law at 

 Leipzig. Thin 

 poet be lost in 

 1850 in con- 

 sequence of 

 expressions of 

 sympath y 

 with the re- 

 volutionary 

 party. 



Taking refuge 

 in S w i t z e r- 

 1and, Mommsen was appointed pro- 

 fessor of Roman law at Zurich. On 

 his return to Germany in 1854, 

 after a period at Breslau he became 

 professor of ancient history at Ber- 

 lin in 1858. In the meantime he 

 had been at work on his Roman 

 History, which appeared between 

 1854-56. With his professorship 

 was bound up the task of editing 

 the Corpus Inscriptionum, which he 

 had been asked to undertake by 

 the Berlin Academy. He also en- 

 gaged in an immense amount of 

 other labours, notably a work on 

 Roman coinage, and two others 

 dealing with Roman law. In 1884 

 appeared his Roman Provinces, the 

 most valuable of all his contribu- 

 tions towards the elucidation of 

 ancient history. From 1873-82 he 

 was a member of the Prussian Par- 

 liament ; in the latter year he was 

 charged with slander of Bismarck, 

 but was acquitted. He died at 

 Charlottenburg, Nov. 1, 1903. 



As an historian Mommsen takes 

 high rank. One of the most pro- 

 found scholars that ever lived, he 

 was indefatigable in the collection 

 and coordination of his material, 

 while he had in an eminent degree 

 the faculty, often denied to the 

 mere scholar, of taking a broad 

 view of the result of his labours. In 

 his judgements, however, he has 

 the characteristic defect of identi- 

 fying might with right, and his His- 

 tory of Rome is in effect a glorifica- 

 tion of Caesarism and a virtual vin- 

 dication of the notion that power 

 belongs to him who has the ability 

 to take and keep it. The literary 

 chapters of the history and his 

 character drawing, although some- 

 times unfair, e.g. Cicero, are excel- 

 lent. There is a very good English 

 translation by W. P. Dickson of the 

 Roman History and the Homan 

 Provinces. See History. 



Momostenango. Town of Gua- 

 temala, in the dept. of Totonicapan. 

 It stands on the N. slopes of the W. 

 section of the Sierra de las Minas, 

 66 m. N.W. of Guatemala. The 

 district to the N. is very fertile, 

 the chief crops being rice, cereals, 

 and beans. Woollen cloth is 

 manufactured. Pop. 18,000. 



Mompoz OR MOMFOX. Town of 

 Colombia, S. America, in the dept. 

 of Bolivar. It stands on the river 



