Chap. IV. ] 
PSILOMELANE. 
lol 
It is noticeable what a large percentage of P2O5 is present in all these 
specimens of psilomelane. The quantity is in fact so large that the 
amount of CaO present is not nearly sufficient for the phosphoric oxide 
to be present as apatite. It is not known therefore in what form the 
P2O5 is present is the mineral. I can only suggest that it forms a 
phosphate with some other base than the lime, possibly a manganese 
phosphate. In the absence of any knowledge on this point I have been 
compelled to disregard this constituent in considering these analyses. 
In the same way the small amounts of sulphur, possibly present as 
barytes, and the minute quantities of Ti02, and of AS2O5, have been 
neglected ; whilst, in view of the small amount returned (0'05 to O'-io 
per cent.), I have not made any allowance for the combined silica ; 
that is, I have not used it to form a corresponding amount of 
braunite, especially as no such second mineral is evident in the speci- 
mens. Leaving these constituents out of consideration, therefore, the 
foregoing analyses can be arranged in terms of manganates as 
follows : — 
Table 13. 
Amlyses of Indian psilomelanes in terms of manganates. 
Guguldoho 
jAvagudem 
Tekrasai. 
Tekrasai. 
Tekrasai 
1157 
1 
1 A. 372 
1 
A. 380 
A. .381 
J. 917 
1 
Fe4(Jrn05)3 . 
2-95 
1122 
0-41 
014 
1 
0-98 
Al4fMn05)3 . 
0-38 
8-02 
0-75 
1-88 
113 
Ba2Mn05 
0 04 
3t5 
20-14 
6-89 
2-7fi 
Ca2MnOi 
0-40 
104 
0-15 
0-50 
0 90 
MgjMnOs 
0-41 
0-57 
0-57 
050 
0 36 
KiMnOs 
4-79 
502 
0-31 
3-60 
4-07 
N»4Mti05 
0-82 
004 
0-27 
0-33 
0-33 
CcwMnOs 
017 
0-25 
0-42 
0-34 
0-59 
Xi2Mn05 
0-34 1 
0-25 1 
0-08 
Cu2Mn05 
007 
013 I 
007 
002 
Zn2irn O5 
0-24 
0-49 
0-65 
0-90 
H4Mn05 
1312 
14-66 
12-73 
10-03 
10-22 
MntMnOi 
74-74 
1 
52 90 
62-28 
72-39 
75-12 
1 
87-82 1 
98-18 
98-99 [ 
97-6S i 
97-46 
