96 URANIUM, ANTIMONY, CHROMIUM, &c. 



lour. When heated with nitric acid it became 

 brown, showing the evolution of nitrous gas, and 

 at last, when the gas had escaped, it became yel- 

 low. The peroxide of iron was precipitated with 

 ammonia, ignited, and weighed. Its colour in., 

 dicating the presence of manganese, it was dis- 

 solved in muriatic acid (with the exception of a 

 few flocks of titanic acid), evaporated to dry- 

 ness, and redissolved in water acidulated by mu- 

 riatic acid. The peroxide of iron was precipi- 

 tated by benzoate of soda. The filtered liquid 

 was mixed with carbonate of soda, and boiled for 

 some time: a brownish precipitate fell, which 

 possessed the characters of oxide of manganese. 

 There could be no doubt from the appearances 

 that both the iron and manganese exist in me- 

 naccanite in the state of protoxide. The result 

 of the analysis was as follows : 



Titanic acid . 57-682 or 6-134 



Protoxide of iron 40-108 \ 



Protoxide of manganese 2 -2 1 / 



100-000 



The two protoxides, having the same atomic 

 weight, may be included together. By this ana- 

 lysis, the atomic weight of titanic acid was 6' 134. 

 Now, it was certain that it had not been quite 

 freed from iron ; for its colour was grey, and not 

 snow white. And Rose lias shown that titanic 



