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MAKGANESE DEPOSITS OF INDIA: ECONOMICS. [pART III: 
larger proportion of combined water than psilomelane. In the psilomelane 
the water is probably present as H4Mn05. 
Manganese-ores, if free from rhodochrosite, should not contain any 
d' • I carbon dioxide. In 28 analyses by the Imperial 
manganese-ores. Institute, however, CO2 is returned as present in 
every case but one. The highest amounts are 
3*49% in a sample from Ghogara in the Pench River; 1"14% in a 
sample of nodule ore from Pali ; and 0*41% in a sample of ore, largely 
braunite, from Gaimukh. In the first two cases the presence of the 
carbon dioxide is to be ascribed to calcite ; for the ores were obtained 
from crystalline limestones ; and in the third case rhodochrosite was 
seen to be present in the ore. In all the other examples the highest 
amount of CO2 is 0*35%; and the average of these 25, excluding the 
foregoing 3, is 0"106%; and as there seems to be no way of 
accounting for the presence of this CO2 by means of visible calcite or 
rhodochrosite, it seems necessary to suppose that there may be 
microscopic amounts of one or other of these minerals disseminated 
through the ores, the calcite having perhaps been introduced by 
percolating waters. Another hypothesis is that these small amounts 
are the result of experimental errors connected with the determination 
of such small amounts of a gas. In 25 analyses by Messrs. J. and H. S. 
Pattinson this constituent is returned as absent in everv case. 
