168 GEOLOGICAL RECONNOISSANCE 



For No. 21. 



Peroxide of manganese 57.92 contains O 21.27 



Protoxide of manganese 39.88 " 8.97"^ 



Baryta 0.29 « 0.03 t OQ 



Lime 1.27 " 0.36 [ 



Water 0.64 " 0.57 J 



Rammelsberg does not include water under the bases of the constitution 

 RO; but seeing no objection to its being considered isomorphous with CaO 

 and BaO, and gaining the advantage of a simple formula, I have classed 

 it with these bases. From the above oxygen-ratio, we obtain for the two 

 minerals the general expression: 



RO. Mn0 2 -|-x MnO 2 



in which x MnO 2 stands for the amount of peroxide of manganese which 

 must be considered as mechanically intermixed with the compound 

 RO.MnO 2 . For the potassa-psilomalane from Ilmenau, Rammelsberg 

 deduced the formula 2 RO. Mn0 2 -|-x MnO 2 . 



For No. 20 we finally obtain the expression: 



(MnO. BaO. HO). Mn0 2 -|-6.37 per cent, of MnO 2 

 mechanically intermixed. 



For No. 21 



(MnO. BaO. CaO. IIO).Mn0 2 --3.84 per cent, of MnO 2 

 mechanically intermixed. 



# 



Uniting in analysis of No. 22, the free oxygen with a portion of the pro- 

 toxide of manganese to the formation of peroxide, we have: 



Peroxide of manganese 62.41 contains O 22.92 



Protoxide of mangauese 19.08 " " 4.29) 



Baryta 2.75 « " 0.52V 4.84 



Oxide of cobalt 0.15 " " 0.03) 



Water 15.61 « 13 97 



100.00 

 The formula 



(MnO. CoO. BaO). 2 Mn0 2 -!-3 HO-l-x MnO 2 

 requires 



Peroxide of manganese (mixed) 9.61 Oxygen-ratio. 



Peroxide of manganese (combined) 52.80 contains O 19.36 4 



