442 Scientific Proceedings, Royal Dublin Society. 
The receiver is next clamped in an inverted position to a tall 
retort-stand: the measuring vessel charged with 50 c.c. of the ab- 
sorbent brought beneath it as shown in fig. 1, and connexion made 
between the short tube of the receiving vessel and the vertical 
tube of the measuring apparatus, this latter tube being previously 
filled with mercury. In performing this operation, the india- 
rubber tube forming part of the plug attached to the receiver is 
pinched between the finger and thumb while the glass rod pre- 
viously attached to it is removed, and the end of the india-rubber 
tube slipped over the tube of the measuring vessel. 
The stop-cock of the measuring vessel is now turned, and the 
mercury reservoir raised so that the charge of absorbent flows 
slowly into the receiver. As soon as all has passed in and some 
mercury has risen above the india-rubber junction, the receiver is 
detached and plugged with the same precaution as before to pre- 
vent escape of air. The receiver is now detached, and rolled 
round so as to wet all parts of its inner surface with the absorbent 
solution. It is then allowed to remain undisturbed for a sufficient 
time for the absorption of the carbonic anhydride to occur. Three 
hours are probably sufficient for the purpose, but in order to be on 
the safe side in all our experiments, twenty-four were allowed. 
The next operation consists in transferring the potash solution 
from the absorbing vessel back again into the measuring ap- 
paratus ; but as it is obviously impossible that the whole can be 
transferred (as a portion clings to the receiver) only an aliquot 
part is removed. The operations for this transfer are precisely 
similar to those employed when running in the charge of absorbent, - 
and need not therefore be described : the only difference being that 
tle mercury reservoir is lowered instead of being raised, and that 
the measuring vessel is filled to the mark 40 c.c. instead of 50 e.e. 
The receiver is now detached, well washed with distilled water, 
and dried, ready for another determination. The measuring 
vessel and its contents are removed to the Adeney apparatus— 
the 40 c.c. of absorbent transferred to the boiling-out flask con- 
taining acidulated gas-free water—and the operation completed 
by boiling out the gases which the absorbent contains (in vacuo), 
and determining the amount of carbonic anhydride they contain 
by measuring the pressure at constant volume before and after 
their treatment with caustic potash. 
