134 Dr. Forrhhammer on the [Aug. 



iiesia from each other. I added to the sulphuric or nitric 

 sokition of these two bodies hydrated peroxide of lead and 

 sulphuric acid, and digested it for some hours. The red solution 

 thus formed contains sulphate of magnesia, manganesic acid, and 

 sulp/iuric acid. — The magnesia is precipitated by carbonate of 

 potash, and the manganesic acid by alcohol, which converts it 

 into brown oxide. As it is impossible that any salt of the prot- 

 oxide of manganese can exist in the same solution which 

 contains the manganesic acid, the magnesia must be free from 

 manganese, unless during the precipitation of the first body the 

 manganesic acid be destroyed, and deutoxide precipitated, which 

 may easily be avoided. To be sure that in the brown powder 

 which remains, and consists of peroxide of lead and sulphate of 

 lead, there is no peroxide of manganese, I boil it with sulphu- 

 ric acid, and heat it gently; water then will dissolve all the 

 sulphate of manganese which would be formed, and carbonate of 

 potash will precipitate the carbonate of manganese, which, toge- 

 ther with the deutoxide before obtained, will, when ignited to a 

 cherry-red heat in an open crucible, give the whole quantity of 

 deutoxide of manganese. Another way in which manganesic 

 acid is formed is when chlorine gas, prepared by means 

 of peroxide of manganese, is absorbed by a solution of potash. 

 The chlorine acid, volatilizing a small quantity of peroxide of 

 manganese, converts it, when acted upon by the potash, into 

 manganesic acid, which is combined with the potash. This has 

 been" long ago remarked by the chemists; and Dr. John, of 

 Berlin, beheved that he had found out a new acid, which was 

 the oxide of an unknown metal ; but a consideration of the 

 effects produced by the different tests will show that this new 

 acid is identical with the manganesic acid. 



The Soliitio}i of the new Metal, 

 according to Dr. John.* 



1. The tincture of gall-nuts 

 gives a precipitate of brown 

 colour like chesnuts. 



2. Ferrochyazate of potash 

 changes the colour directly into 

 lemon-yellow. 



3. Carbonate of potash does 

 not change it. 



4. Alcohol immediately alters 

 its colour into green. 



The Solution of Manganesiate 

 of Potash. 



1. The same effect. 



2. The same effect when the 

 solution of the manganesiate is 

 very weak, but when it is con- 

 centrated, it makes a brown 

 precipitate. 



3. The same. 



4. The same effect is pro- 

 duced. 



I obtained the same body when I passed chlorine through 



• John, Laboratorium. Berlin, 1811. 



