284 T)r. Henry on the action of finely divided platinum on 
was converted into carbonic acid, and the olefiant gas remained 
in its original volume. 
2d. By exposing in a similar manner 20 measures of car- 
bonic oxide, 21 of carburetted hydrogen, and 36 of oxygen, to 
a temperature below 400° Fahrenheit, the carbonic oxide 
was entirely acidified ; and on washing out the carbonic acid 
by liquid potash, the carburetted hydrogen was found unal- 
tered, mixed with the redundant oxygen. 
3d. A mixture of 10 measures of olefiant gas, 10 of carbu- 
retted hydrogen, and 58 of oxygen, being heated in contact 
with the sponge to 510° Fahrenheit, the olefiant gas was 
silently but entirely changed into carbonic acid, while the 
carburetted hydrogen was not at all acted upon. 
4th. By acting with the sponge upon 42 measures of car- 
buretted hydrogen, 22 of carbonic oxide, 22 of hydrogen, 
and 28 of oxygen, first at a temperature of 340° Fahrenheit, 
which was raised gradually to 480°, all the carbonic oxide 
was changed into carbonic acid, and all the hydrogen into 
water ; but the carburetted hydrogen remained undiminished 
in quantity, and was found, after removing the carbonic acid, 
mixed only with the redundant oxygen. In this experiment, 
the diminution of volume had continued some time before 
there was any perceptible formation of water, the attraction 
of carbonic oxide for oxygen appearing to prevail over that 
of hydrogen. The same precedency in the formation of car- 
bonic acid is always apparent, when carbonic oxide and 
hydrogen, mixed even with oxygen enough to saturate both 
gases, are raised to 350° Fahrenheit. 
By thus carefully regulating the temperature of the mercu- 
rial bath, the action of oxygen upon several gases, (carbonic 
