1878.] 
Notices of Books. 
279 
The analyses of Raniganj coal, by Mr. A, Tween, show that 
the Indian samples are less contaminated with sulphur than the 
average of English specimens, but contain more ash and more 
oxygen. The Dumakunda and Benodakotta coals, however, 
have a good heating power, since, if the combustion of pure 
carbon yield 8080° C., they afford respectively 7040° and 7023°. 
The best gas-coal is that of Sanktoria, which furnishes about 
9000 cubic feet per ton. 
Memoirs of the Geological Survey of India. Vol. xii., Part 2. 
Mallet : Coal-fields of the Naga Hills bordering the 
Lakhimpur. Calcutta : Geological Survey Office. 
The deposits of coal on the Brahmaputra and its affluents in 
Upper Assam are exceedingly valuable. The coal is of good 
quality, and nothing seems requisite save the improvement of 
the navigation of the river to bring it into use in Bengal, and 
supersede the necessity of importation from England. Petroleum 
is also found in quantity, but until the means of communication 
are improved it cannot compete in the market with that brought 
from Rangoon and from America. Some of the coal-beds are of 
very considerable thickness. Thus in a total seCtion of 47 feet 
10 inches the coal-beds alone amount to 37 feet, the thickest bed 
being 25 feet. It is an unfortunate circumstance, however, that 
the measures have a high general dip towards the hills, and the 
seams must rapidly sink to a depth below which the coal could 
not be profitably worked. Still the author estimates that as a 
minimum 9,000,000 tons of marketable coal would be easily 
procurable from the seams already known to exist. Between 
Tipam and Bornarchali there is a further minimum of say 
10 millions of tons in a marketable state, whilst the Nazira field 
will add a further supply of 7 millions. In the unsettled state 
of the political horizon the existence of a supply of coal for 
naval purposes independent of importations from Britain is of 
the highest importance. Pyritous shales seem abundant, and 
the manufacture of copperas and alum could probably be con- 
ducted with success. The iron ore in the sub-Himalayan beds 
is inexhaustible, but the quality is very poor, and the rarity of 
limestone in the Naga hills must always be a difficulty in the 
way of smelting operations on a large scale. 
