200 MANGANESE, ORES OF 



48 hours, to a dull red heat. The proportions employed by Mr. Condy are 1J 

 ton of soda-ash, caustified in the usual way, to 7 cwts. of peroxide of manga- 

 nese. The product of the reaction is treated with a sufficient quantity of -water to 

 convert (partly, at all events) the manganate into permanganate ; and the solution is 

 evaporated to an appropriate state of concentration or to dryness. In some cases 

 Mr. Condy transforms the manganate into the permanganate by the addition of 

 sulphuric acid. On evaporating the solution thus formed, crystals of sulphate of 

 sodium separate ; these are fished out, and the liquid is ultimately boiled down to 

 dryness. See DISINFECTANTS. 



MANGANESE (Eng. and Fr. ; Mangan, Braunsteinmetall, Ger.) is a greyish- 

 white metal, of a fine-grained fracture, very hard, very brittle, -with considerable 

 lustre, of specific gravity 8 - 013, and requiring for fusion an extreme heat. It 

 should be kept in closely-stoppered bottles, under naphtha, like potassium, because 

 with contact of air it speedily gets oxidised, and falls into powder. It decomposes 

 water slowly at common temperatures, and rapidly at a red heat. Pure oxide of 

 manganese can be reduced to the metallic state only in small quantities, by mixing 

 it with lamp-black and oil into a dough, and exposing the mixture to the intense heat 

 of a smith's forge, in a luted crucible ; which must be shaken occasionally to favour 

 the agglomeration of the particles into a button. Thus procured, it contains, however, 

 a little carbon. Some improvements in the reduction of manganese have recently 

 been effected by Mr. Hugo Tamm. 



Manganese is supposed to perform an important part in the compound of iron, 

 known as Spiegeleisen, which is now so largely employed in the manufacture of the 

 Bessemer Steel. See SPIEGELEISEN and STEEL. 



MANGANESE. ORES OP. There are two principal ores of this metal, which 

 occur in great masses ; the peroxide, and the hydrated oxide ; but all the ores of 

 manganese are described in the following paragraphs : 



Pt/rolusite, or grey manganese ore, has a metallic lustre, a steel-grey colour, and 

 affords a black powder. Specific gravity 4'85. Scratches calc-spar. It effervesces 

 briskly with borax at the blowpipe, in consequence of the disengagement of oxygen 

 gas. This is the most common ore of manganese, and a very valuable one, being the 

 substance mostly employed in the manufacture of chloride of lime and of flint glass. 

 It is the peroxide. It contains manganese. 63'3 ; oxygen, 36*7. Great quantities 

 are found near Tavistock in Devonshire and Launceston in Cornwall. 



Braunite is a dark brown substance of glassy metallic lustre, affording a brown 

 powder. Specific gravity 4 - 8. It scratches felspar, but is scratched by quartz. In- 

 fusible 'at the blowpipe, and effervesces but slightly when fused with glass of borax. 

 It is the sesquioxide, containing manganese,69'68 ; oxygen, 30*32. It gives out at a red 

 heat only 3 per cent, of oxygen. Hausmannite is a rarer ore, consisting of the protoxide 

 and sesquioxide of manganese. % 



Manganite is brownish-black or iron-black, powder brown, with somewhat of a 

 metallic lustre. Specific gravity 4-3. Scratches fluor-spar. Affords water by cal- 

 cination in a glass tube ; infusible at the blowpipe ; and effervesces slightly when 

 fused with glass of borax. It consists of manganese, 62'68 ; oxygen, 27'22 ; water, 

 lO'lO ; and is therefore a hydrated sesquioxide. 



Manganese-blende, or sulphide of manganese, has a metallic aspect ; is black or 

 dark steel-grey. Specific gravity 3 - 95. Has no cleavage ; cannot be cut. Infusible, 

 but affords, after being roasted, distinct evidence of manganese by giving a violet 

 tinge to soda at the blowpipe. Soluble in nitric acid ; solution yields a white pre- 4 

 cipitate, with the ferrocyanide of potassium. It consists of sulphur, 37'90 ; manga- 

 nese, 62-10. 



Diallogite ; Carbonate of Manganese. Specific gravity 3'4. Affords a green frit by 

 fusion with carbonate of soda ; is soluble, with some effervescence, in nitric acid ; 

 solution, when freed from iron by succinate of ammonia, gives a white precipitate, 

 with ferrocyanide of potassium. Carbonic acid, 38'20 ; protoxide of manganese, 6T80. 



Rhodonite, or Hydrosilicate of Manganese, is a brownish-red-looking substance, 

 which yields a yellowish-brown powder, and water by calcination ; is acted on by 

 muriatic acid, but affords no chlorine. It consists of silica, 45 ; protoxide of manga- 

 nese, 64'1. 



Wad, or Bog Manganese, is the old English name of the hydrated peroxide of 

 manganese. It occurs in various imitative shapes, in froth-like coatings upon other 

 minerals, as also massive. Some varieties possess imperfect metallic lustre. The 

 external colour is a dark brown of various shades, and similar in the streak, only 

 shining. It is opaque, very sectile, soils and writes. Its specific gravity is about 3'7. 

 Mixed with linseed-oil into a dough, black wad forms a mass that spontaneously in- 

 flames. The localities of wad are particularly Cornwall and Devonshire, the Hartz, 

 and Piedmotot. Wad from Devonshire gave oxide of manganese, 79'12 ; oxygen, 8'82 ; 

 water. 10-06. 



