SOLVENT POWER OF WATER ON SILICEOUS MINERALS. 227 
The nitric acid sets free the whole of the bromic, and this 
at the moment of liberation is resolved into bromine and 
oxygen. 
In conclusion, the author remarks that the action of nitric 
acid upon these salts, affords a ready method of distinguishing 
them from one another. 
Trans, of British Association, for 1840, 
ART. XLIX. ON THE SOLVENT POWER EXERCISED BY 
WATER, AT HIGH TEMPERATURES, ON SILICEOUS MINE- 
RALS. By Julius Jeffreys. 
" The few remarks I have to offer, have reference to a 
paper read before the Royal Society of London, last spring. 
It briefly related an experiment made to determine the action 
of w T ater, in the form of its vapor, upon siliceous minerals, at 
a very intense heat. The experiment was upon a large scale, 
and consequently very costly, and the results were curious, 
as establishing a very powerful action, by water, on siliceous 
minerals, when the temperature is sufficiently high." 
Mr. Jeffrey's exhibited a large drawing to the British Asso- 
ciation, showing the construction of a large boiler, erected 
near Furrukabad, a large city S00 miles west of Calcutta. 
It was the only one of the kind in India, and was employed 
for vitrifying brown stone, the manufacture of which Mr. 
Jeffreys had succeeded in introducing into the country. It 
was heated by four exterior furnaces, each six feet long and 
five wide. The kiln inside was fifteen feet in diameter and 
twenty-four feet high. The fuel was wood, and the utmost 
effect any alkali, which might be supposed to rise in its vapor, 
ordinarily produced, was a slight glazing of some of the brick 
surfaces in the kiln, near the entrance of the flame ; an ap- 
pearance which is also seen with other fuel, and with which 
