Chap. XXI Y.] rarer constituents of ores. 
523 
Tekrasai, both localities being in Singhbhum. A specimen of hollancUte 
from Kajlidongri analysed by Mr. Winch .showed 17-59% BaO. The 
barvta seems to be present in all or nearly all of these ores in the 
form of barium manganate, BagMnO-, in the psilomelane or hollandite. 
It may also replace manganese in braunite as the molecule BaMnOg. 
The average amount in the 78 ^samples and specimens noticed above 
is 1-88%. 
Lime is almost invariably present in Indian manganese- 
ores. The 45 complete analvses show a maxi- 
Liine in manganese-mes. . ^ rrvo/ • i x • i -i i 
mum 01 0- dO% m a sample oi mixed psilomelane 
and braunite from Lohdongri, and a minimum of 0-00% in a picked 
specimen of pyrolusite from Pah. The average of the 45 is 107%. In 
many cases the lime is probably present as a manganate, Ca2MnO-, as a 
part of the psilomelane or hollandite ; but in some cases it probably 
replaces a portion of the manganese in braunite. e.g., in the specimen 
of this mineral from Sitapar analysed by Mr. Blyth, and found to 
contain 4-28% CaO. 
Magnesia is another of the almost invariable constituents of Indian 
manganese-ores, only one analysis out of 45 
Magnesia in manganese- growing it absent. This is a Specimen of mixed 
ores. . . - . 
hollandite and braunite from Junawani. The 
maximum amongst these 45 analyses is 3*15% in a specimen from Kachi 
Dhana consisting almost entirely of braunite. The average amount 
in the 45 analyses is 0-53°{) MgO. The magnesia probably plays a 
similar part in manganese-ores to the lime. 
Alkalies sometimes form quite an important part of the Indian man- 
ganese-ores, potash being much more important 
Potash in manganese- t^an soda. In 25 analyses bv J. and H. S. 
ores. 
Pattinson the lowest amount of K2O is 0-05% 
in specimens from Guguldoho and Kajhdongri. In 10 cases the percentage 
of K2O is over 1, the highest amounts being 3-75% in psilomelane con- 
taining braunite from Kodur, 3-31% in hollandite with braunite from 
Balaghat, 3-25% in lead- like psilomelane from Avagudem, 3-10% in 
psilomelane from Guguldoho, and 2 63% in psilomelane from Tekrasai. 
The average amount of K2O in these 25 analyses is 117%. In 21 
analyses by the Imperial Institute the amount of K2O ranges from a 
trace in four cases — namely, braunite ^\^th a little psilomelane from Kachi 
Dhana, pyrolusite from Pali, vredenburgite from Beldongri, and braunite 
containing a little psilomelane from Kacharwahi — to 0-82% in a sample 
III H 2 
