638 MANGANESE DErOSITS OF INDIA : DESCRIPTIVE. [PaRT IV : 
These 12 analyses give the following range and mean values for the 
several constituents : — 
Limits. 
Mean. 
Mc;ui ex- 
cluding 
Nos. 3 
and 5. 
Manganese ..... 
28 to (iO 
85 
39-07 
44-77 
Iron ...... 
51 
88 to 0 
10 
16-87 
10-33 
Silica ...... 
0 
65 to 2 
70 
1-55 
1 -40 
Phosphorus ..... 
0 
Oil to 0 
119 
0 0-12 
0-045 
It will be seen from these analyses that the manganese and iron 
contents of the ores are very variable, the percentage of iron increasing 
as that of manganese decreases, so that the total of the two constituents 
lies between 48 and 61%, averaging 56. In the fourth column above 
are given the mean values of the various constituents, excluding the 
analyses of Nos. 3 and 5, which, being evidently nearer iron-ores than 
manganese-ores, would not be despatched with the latter. This column 
may therefore be taken as giving roughly the composition of the ores 
that would be mined at Talevadi ; and considering the unusually small 
amounts of silica and phosphorus and the proximity of the locality to 
the port of Mormugiio, it is probable that ore of such quality would find 
a ready market. It is evident, however, from the descriptions of the 
specimens given above that the appearance of the ore may be very 
deceptive and that two equally rich-looking pieces of psilomelane may 
differ widely in their manganese contents. Thus, Nos. 9 and 12 do not 
differ much in their physical appearance, both being dull varieties of 
psilomelane ; and yet No. 9 showed on analysis 39 per cent Mn and 
18 per cent Fe, while No. 12 showed 51 per cent Mn and 5 per cent Fe. 
Hence, to ensure the despatch of a fairly uniform product, it is evident 
that careful analytical work would be necessary. 
Although the ore is probably of sufficiently good quality to be mar- 
ketable and the total quantity available is not inconsiderable, yet the 
manganiferous nodules are so irregularly distributed in the laterite — as 
shown by the large number of sections exposed in the various pits — that 
this occurrence can be only doubtfully regarded as a paying proposition. 
Probably in times when the price per unit of manganese rules high 
(one shilling and over) these nodules could be worked at a profit ; while 
