Cll.vr. XXIV.] RARER CONSTITUENTS OF ORES. 
527 
In the 25 analyses of specimens and samples by J. and H. S. Pattin- 
son zinc oxide is returned as absent in 9 cases, 
Zinc ill niiinoranese-ores. . i • i , • i • ,i 
as a trace m one, and is determined m the 
remaining cases. The maximum amount of ZnO is 0'55%, found in a 
specimen of psilomelane from Tekiasai. Amounts of 0*40% and 0'30% 
ZnO were found in two other specimens of the same mineral from the 
same locality. The average amount in the whole 25 analyses is 0 " 102% 
ZnO. The analysis of the Junawani sample taken by Mr. Goodchild, 
noticed in the preceding paragraph, shows 0'070% ZnO. An analysis by 
Messrs. Pattrnson and Stead of a 300-ton cargo of Kodegaon ore shows 
a trace of this constituent. 
It is noticeable that all the rare metallic constituents, cobalt, nickel, 
copper, lead, and zinc, found in the Indian manganese-ores, tend to occur 
in greatest amount in specimens of wad and psilomelane. The most 
noticeable examples are the wad-like psilomelanes of Sontulai and 
Tekrasai. It is probable that these constituents tend to take the form 
of manganates of the general formula RoMnOs in the ores in which 
they are found, though they might also occur in braunite in molecules 
of the general formula RMn03. 
In the 25 analyses by J. and H. S. Pattinson titanic oxide is returned 
as absent in four cases, as a trace in one, 
Titanium in manganese- - . • i • ,i - • i 
ores. and is determined in the remaimng analyses. 
The maximum amounts are 0' 14% in a specimen 
of vxedenburgite from Garividi. 0-14% and 0'12% in two samples of 
mixed psilomelane-braunite ores from Kajlidongri, and 0*13% in a 
specimen of speckled ore (psilomelane, braunite, and soft oxides) from 
Guguldoho. The average in the whole 25 analyses is 0'058% Ti02. 
The amount of combined water in Indian manganese-ores varies 
greatly with the nature of the ore. It is never 
Combined water in man- ., t < - i ii i • i j 
ganese-ores. in 4d analyses the highest amounts are 
7 -30% in wad from Garbham ; 6 '16^ in 
beldongrite, a variety of psilomelane from Beldongri ; 5 • 50% in wad 
from Kodur ; and 4 • 40% in material intermediate in physical appearance 
between wad and psilomelane, from Garbham. The average amount in 
the 45 analyses is 2 '01%. It may be stated as a rough rule that the 
larger the amount of psilomelane in an ore the larger is likely to be the 
amount of combined water ; and the larger the amount of braimite the 
smaller the amount of combined water : whilst wad contains an even 
