MANETHO MANGANESE. 



liberty of Zurich. After the death of Bruns, he was 

 chosen burgomaster. He was a lover of poetry, and 

 formed a collection of 140 love-soups, called after 

 him the Manesse collection. It remained until the 

 beginning of the seventeenth century in Switzerland, 

 but was carried off, and, during the thirty years' war, 

 found its way to Paris, where it was discovered, in 

 1726, by Ch. von Bartenstein. Part of the manu- 

 script was published in 1748 (2 vols., Zurich) ; in 

 1758, and 1759, complete, by Bodmer and Brei linger. 

 It is important in the history of German literature. 



MANETHO ; an ancient Egyptian historian, who 

 was high priest of Heliopolis, in the reign of Ptolemy 

 Philadelphia, about 304 B. C. He wrote in Greek 

 a history of Egypt, from the earliest times to the last 

 years of Nectanebis, and pretended that he had taken 

 it from the sacred pillars of the first Hermes Trisme- 

 gistus ; the inscriptions on which, after the flood, were 

 translated into Greek, but written in the sacred cha- 

 racters, and deposited in the sacred recesses of Egypt. 

 The manifest absurdity of this pretension induces 

 several writers to think, that some mistake or cor- 

 ruption has taken place in the passage of Eusebius 

 which relates it. The work of Manetho, which is 

 lost, consisted of three parts, the first of which con- 

 tained the history of the gods or heroes, and the 

 second and third that of twenty dynasties of kings, 

 which, having been epitomized by Julius Africanus, 

 are recorded by Eusebius. Several fragments of 

 Manetho are preserved by Josephus, in his work 

 against Apion. See Seyffarth and Hieroglyphics. 



MANFREDI, EUSTACHIO ; an eminent mathema- 

 tician and astronomer, born in 1674, at Bologna, in 

 Italy. He applied himself to the cultivation of ma- 

 thematical science, and, in 1698, was appointed pro- 

 fessor of mathematics in the university of Bologna. 

 In conjunction with Victor Stancari, he commenced a 

 series of astronomical observations, of which he 

 afterwards published an account in his Schedce Mathe- 

 matics. In 1703 appeared his treatise on the Solar 

 Macula?; and the following year he was chosen regent 

 of the college of Montalto, and also surveyor-general 

 of the rivers and waters of the Bolognese territories. 

 In 1705, he published a work on the Reformation of 

 the Calendar; and he afterwards began the composi- 

 tion of his Ephemerides Motuum ccelestium, which 

 he carried on from 1715 to 1725. On the foundation 

 of the institute of Bologna, in 1712, Manfredi was 

 appointed astronomer to that establishment. He was 

 admitted an associate of the royal academy of sciences 

 at Paris, and, in 1729, a foreign member of the royal 

 society of London. He died in 1739. Besides the 

 works already noticed, he was the author of other 

 mathematical and astronomical productions ; and 

 after his death, appeared a volume of his poems. 



MANGANESE, in the condition of an ore, had 

 been used in certain arts, before its nature, as a dis- 

 tinct metal, was known. Scheele and Bergman, from 

 an examination of this ore, inferred that it chiefly con- 

 sisted of the oxide of a metal. To obtain the metal, 

 the mineral is dissolved in muriatic acid, the oxide of 

 iron in the solution precipitated by ammonia, and the 

 solution itself evaporated to dryness; the residuum, 

 after heating to expel the muriate of ammonia, is pure 

 oxide of manganese, which is made into a paste, with 

 a small quantity of oil and charcoal, and exposed, in 

 a crucible, to the most intense luiit of a powerful 

 wind-furnace ; the result of the process is the man- 

 ganese in the metallic form. Hydrogen gas, passed 

 over the heated oxide, will also reduce it. The metal 

 is of a white colour, with a shade of gray, having a 

 moderate lustre, which tarnishes, however, on expo- 

 sure to the air. Its texture is granular ; it is brittle 

 and hard ; specific gravity, 8. ; heated in oxygen or 

 chlorine, it takes tire, and forms an oxide or chloride. 



The oxides of manganese have exercised the skill of 

 many chemists, and are hardly yet determined beyond 

 controversy. Three, most probably four, well defined 

 oxides may be obtained ; and some intermediate 

 oxides, compounded of these, exist in nature. The 

 protoxide is best obtained by transmitting hydrogen 

 gas over the deutoxide, peroxide, or carbonate of 

 manganese, ignited by a spirit-lamp, in a glass tube. 

 It is permanent in the air, but, when heated to 600 

 Fahr., it absorbs oxygen very rapidly, and, at a low 

 red heat, it passes from its green colour, almost 

 instantaneously, into black. It consists of manga- 

 nese 76.82, and oxygen 23.18. It is the basis of all 

 the proper salts of manganese, which, when pure, 

 are colourless. The deutoxide is prepared by expos- 

 ing the nitrate or peroxide of manganese, for a con- 

 siderable time, to dull ignition. It is found native in 

 the prismatoidal manganese ore (gray oxide of man- 

 ganese), and consists of 70 metal and 30 oxygen. 

 When heated with sulphuric acid, oxygen gas is 

 extricated with effervescence, and a protosulphate 

 results. The peroxide exists native and crystalliml 

 in perfect purity. It may be artificially prepared, by 

 heating the dry proto-nitrate till a uniform black 

 mass be formed, which must be pulverized, washed 

 while hot with strong nitric acid, and again gently 

 calcined with constant stirring. It contains twice as 

 much oxygen as the protoxide. The red oxide is 

 formed by exposing the nitrate, or peroxide of man- 

 ganese, to a white heat, out of the influence of smoky 

 vapours. It has a brownish-red colour when cold, 

 and is nearly black while warm. It consists of two 

 proportionals of the protoxide, and OIK; of the per- 

 oxide. It dissolves, in small quantity, in dilute sul- 

 phuric acid, without disengagement of oxygen gas, 

 forming an amethyst-red liquid. On heating this 

 solution, or dilute sulphuric acid, or the red oxide, 

 oxygen is evolved, the colour disappears, and a proto- 

 sulphate remains. Strong muriatic acid dissolves 

 the red oxide into a coloured solution, which exhales 

 chlorine, and gradually passes into a colourless proto- 

 muriate. A compound, possessing very singular 

 properties, as respects the colours to which it gives 

 rise when in solution, and which, from this circum- 

 stance, has received the fanciful name of the mineral 

 chameleon, is formed by fusing together the native 

 black oxide of manganese and potash, or its carbon- 

 ate, which, on being dissolved in water, communi- 

 cates to it a greenish-blue colour. The solution, on 

 standing a little time exposed to the air, lets fall the 

 oxide of iron which it contains, and the colour 

 becomes blue ; and, on the addition of warm water, 

 or an acid, the solution assumes a violet colour, from 

 which it soon passes to red, brown, black, and lastly 

 becomes colourless. When the colour of the solution 

 is bluish- green, the manganese is believed to be 

 united with the alkali, in the condition of manganes- 

 eous acid ; and when it is red, the manganese is 

 supposed to be in the state of manganesic acid. The 

 manganeseous acid is, according to this view, very 

 easy of decomposition. When combined with potash, 

 it forms a submanganesite ; and whenever the potash 

 is saturated, or its action weakened, the manganese- 

 ous acid is decomposed into deutoxide of manganese 

 and manganesic acid ; hence the changes of the solu- 

 tion. According to the experiments of Frommherz. 

 the manganesic acid has a dark carmine-red colour, 

 tastes sweetish at first, but afterwards bitter and 

 astringent, and is destitute of smell. When heated 

 with care, it volatilizes. It is decomposed by a current 

 of hydrogen gas, the hydrogen acids, carburet of sul- 

 phur, the metals, and all organic substances. The salts 

 of manganese are usually prepared from the black per- 

 oxide. The acids, which have a strong affinity to 

 the protoxide, expel the excess of oxygen, especially 



