532 MANGANESE. 



tity of carbonate of manganese will be obtained, sufficient to 

 precipitate the iron from the other three fourths of the liquid, 

 and which may be used for that purpose after it has been 

 washed. The chloride of manganese, is precipitated white, 

 when free from iron, without any shade of blue, by the 

 ferrocyanide of potassium. The crystals retain one, from 

 their four equivalents of water, at 212 (Brandes), but may be 

 made anhydrous at a higher temperature. Brandes finds 100 

 parts of water to dissolve at 50, 38.3 ; at 88, 46.2; at 144.5, 

 55 parts of the anhydrous salt. A higher temperature instead 

 of increasing the solubility of this salt diminishes it. Absolute 

 alcohol dissolves half its weight of the anhydrous chloride of 

 manganese, and affords by evaporation in vacuo, a crystalline 

 alcoate, containing two equivalents of alcohol. 



The corresponding fluoride of manganese forms a double salt 

 with fluoride of silicon, which is very soluble in water and crys- 

 tallizes in long regular prisms of six sides. The formula of 

 this double salt is, after Berzelius, 2Si F 3 + 3Mn F + 21HO. 



Carbonate of manganese is a white insoluble powder, 

 which acquires a brown tint when exposed in the dry state at 

 140. It is decomposed by a red heat. Carbonate of manga- 

 nese occurs in the mineral kingdom, but never in a state of 

 purity, being mixed with the carbonates of lime and iron, which 

 have the same crystalline form. Its presence in spathic carbo- 

 nate of iron is said to be the cause, why the latter yields an 

 iron peculiarly adapted for the manufacture of steel. 



Protosulphate of manganese ; Mn O, SO 3 -f 7 HO. A solution 

 of this salt used in dyeing and entirely free from iron, is pre- 

 pared by igniting the peroxide of manganese mixed with about 

 one-tenth of its weight of pounded coal, in a gas retort. r lhe 

 protoxide thus formed is dissolved in sulphuric acid, with the 

 addition at the end of a little hydrochloric acid ; the sulphate is 

 evaporated to dryness and heated again to redness in the gas 

 retort. The iron is found after ignition in the state of peroxide 

 and insoluble, the persulphate of iron being decomposed, while 

 the sulphate of manganese is not injured by the temperature of 

 ignition and remains soluble. The solution is of an amethystine 

 colour, and does not crystallize readily. When cloth is passed 

 through sulphate of manganese and afterwards through a 

 caustic alkali, protoxide of manganese is precipitated upon it, 

 and rapidly becomes brown in the air, or it is peroxidised at 



