MANGANESE. 373 



mass is immediately resolved into two substances, 

 tritoxide of manganese, and manganesic acid. 

 The former remains mixed with the sulphate of 

 barytes ; but the latter dissolves in water, and 

 gives that liquid a beautiful red colour. 



7 When tritoxide of manganese and nitre are 

 heated, the solution is at first green, and it gra- 

 dually passes into red, while, at the same time, 

 a quantity of deutoxide of manganese precipi- 

 tates. When an acid is poured into the green 

 coloured solution, it becomes red ; an alkali, on 

 the other hand, renders the red coloured solution 

 green. When alcohol, or any animal or vege- 

 table substance, is added to the red solution, 

 deutoxide of manganese precipitates ; while, at 

 the same time, the red colour is destroyed. 



Dr. Forchhammer is of opinion, from these 

 and similar phenomena, that there are two acids 

 of manganese, which he calls manganous and 

 manganesic acids the former containing the 

 least, and the latter the most oxygen. The 

 manganous acid exists in the green coloured 

 liquid, which is a compound of that acid arid 

 potash ; while the red salt is a compound of 

 manganesic acid and potash. 



8. To determine the composition of manga- His method 



i TX -n i i i .of analyz- 



nous acid, Dr. Jborchhammer prepared a quantity ing ma n- 

 of the manganite of potash, and decomposed it 

 by the addition of a solution of nitrate of lead. 

 A dark coloured precipitate fell, consisting of a 



A a 3 



