CiiAP. XXXVI.] 
NAGPUR : GUGULDOHO. 
951 
mineral, and the composition of which is not known, it will not be 
possible to rearrange this analysis in terms of the mineral composition 
of the ore. The striking points about this sort of ore, from the commer- 
cial point of view, are its freedom from silica and its low percentage of 
phosphorus. In spite of this, however, the manganese amounts to only 
42 per cent., being to a considerable extent replaced by iron. If such 
ore could be stacked separately in considerable quantity it would form 
a valuable ferruginous manganese-ore, although under present circum- 
stances it could not be exported at a profit. It is very exceptional 
for the sum of the percentages of manganese and iron in a manganese- 
ore to be as high as 64 per cent. 
A specimen was also selected for analysis of a piece of very homogen- 
eous psilomelane, forming a large hepatiform mass of concentric structure. 
The analysis of this is given on pages 100 to 106, where the composition 
of the mineral is also discussed. It is found to be a potash-psilomelane. 
I will reproduce here only the constituents of commercial importance : — 
Manganese 57-78 
Iron 1-05 
Silica (total) 0-2.5 
Phosphorus ......... 0'3G6 
It will be seen that except for the high phosphorus this is an ore of 
exceedingly good quality. 
About 900 tons of ore had been stacked and from this I took sample 
No. 36, which was composed of about equal parts of concretionary 
psilomelane and the sooty psilomelane-braunite ore. The analysis, by the 
Imperial Institute, shows : — 
Sumpk No. 36. 
Manganese peroxide . . . . . . . . 62 ■ 03 
Manganese protoxide . . . . . . . .8-75 
Ferric oxide 23-34 
Silica (combined) . . . . . . . .1-58 
Silica (free) 1-32 
Phosphoric oxide ........ 0-42 
Moisture at 100°C 0-54 
This is equivalent to :— 
Manganese . . . . . . . . .46-24 
Iron . . . . . . . . . .16-34 
Silica 2-90 
Phosphorus 0-183 
Moisture .......... 0*54 
and indicates that the ore contains only about 16 per cent, braunite on the 
average. It is evident from this analysis that the ores being high in 
both iron and phosphorus, with a corresponding reduction in the 
percentage of manganese, are akin in chemical composition, as in physical 
aspect, to those of the Vizagapatam district, rather than to those of this 
area. 
