798 
MANGANESE DEPOSITS OF INDIA : DESCRIPTIVE. [PaRT IV ; 
Free silica 
Phosphoric oxide 
Arsenic oxide 
Combined water 
Moisture at 100°C. 
Carbon dioxide 
Thib is equivalent to :- 
0-48 
0-07 
0-002 
0-39 
0-07 
0-04 
99-552 
Manganese" . . . . . . . . . . .55-94 
Iron 3-44 
Silica (total) I-7I 
Phosphorus ........... 0-031 
In calculating this ore into terms of its mineral composition T found 
that the best interpretation is to assume that the braunite has the cus- 
tomary formula 3Mn203.MnSi03, and that the crystalline prismatic 
mineral is a manganate allied to hollandite, which it resembles in appear- 
ance, the high percentage of baryta being an especially good indicator 
of the presence of a manganate. The mineralogical composition can be 
stated as follows : — 
Apatite 
Calcite .... 
Braunite (3Mn203. MnSiOs) 
Hollandite : — 
re4(Mn05)3 
Al4(Mn05)3 
Ba2Mn05 
Ca2Mn05 
Mg2Mn05 
H4Mn05 
Mn2Mn05 
0-16 
0-09 
12-32 
9 
65 
0 
91 
8 
25 
0 
63 
0 
68 
1 
60 
63 
96 
85 
58 
Free Silica 
Moisture 
AS2O5 . 
Surplus oxygen 
85-58 
0-48 
0-07 
0-002 
0-85 
99-552 
The surplus of 0'85 % of oxygen, may be due to experimental 
errors in its determination, or perhaps more probably it can be taken 
as indicating that a portion of the manganese manganate is in the 
manganic form Mn4fMn05)3 and not all in the manganous form as 
represented. 
I took a sample of the ore from the two outcrops and all the pits and 
trenches along the main band of ore. From pit No. 1 and the two out- 
