1813.] a Chemical Knoivledge of Manganese. 271 



grey ore of manganese. The experiments must be made upon 

 pounds of the ore at once. 



Remarks on the preceding Paper. By the Editor. 



I considered the preceding paper as highly worthy of publica- 

 tion, because it contains many circumstances respecting manga- 

 nese with which chemists ought to be acquainted, but which do 

 not seem to be generally known in this country. At the same 

 time the paper exhibits some striking imperfections, which it 

 may be proper to notice for the sake of our chemical readers, 

 who may not have an opportunity of knowing exactly the present 

 state of this part of chemical science. 



1. Dr. John's method of procuring pure oxide of manganese 

 is exceptionable. How he was able to succeed by means of it we 

 cannot say ; but certainly no other person has been able to verify 

 his results. We shall insert a paper on the subject by Bucholz, 

 which will convince our readers of the truth of our remarks. 

 With respect to the separation of iron and manganese there are 

 four methods of proceeding, all of which succeed tolerably well. 

 i. Gehlen's method is the best. It consists in dropping succinate 

 of potash or succinate of ammonia into the impure manganese 

 solution, previously brought as near as possible to a state of 

 neutralization. The whole iron falls in the state of succinate, 

 while the manganese remains in solution. The objection to this 

 method is the high price of succinic acid, which Gehlen endea- 

 vours to obviate by saying that the succinic acid may be reco- 

 vered by boiling the precipitated succinate of iron in an alkaline 

 ley; but every practical chemist must be aware that such a pro- 

 posal is quite absurd. The time lost, and the great trouble, 

 would be more than equivalent to the price of the succinic acid. 

 2. Berzelius, in order to obviate this objection, substituted 

 benzoic acid for succinic. It appeal's from the experiments of 

 Hisinger (Aj'handlingar i Fysik, Kemi och Miner alogi, t. 3, p. 

 152,) that this method answers pretty well. 3. The impure 

 oxide of manganese may be dissolved in sulphuric acid, the solu- 

 tion evaporated to dryness, and exposed to a red heat. The 

 sulphate of iron is decomposed by this process; but the sulphate 

 of manganese remains unaltered. Hence the latter continues 

 soluble in water; but not the former. This process was pro- 

 posed by Dr. John in the preceding paper. 4. The impure 

 manganese may be dissolved in muriatic acid, the solution eva- 

 porated to dryness, and exposed to a red heat in close vessels. 

 The ferrane sublimes, while the manganesane remains unaltered. 

 This process may be repeated two or three times, and then the 

 oxide of manganese will be freed from iron. This process was 



