1878.] 
Liquefaction of Oxygen, 
239 
R. A tube, 125 millimetres in diameter and i*i metres long, containing liquid 
sulphurous acid. 
P3, p 4 . Double-a&ion exhaustion and force pumps, exhausting sulphurous acid 
gas from the tube R. 
Q. A tubular condenser of sulphurous acid compressed by the pumps. This 
body, when liquefied, returns by the small tube f to the tube R. The 
cold water for condensing the sulphurous acid passes through the aper- 
tures E E. 
ci. Entry for liquid carbonic acid. 
. Exit for the vapourised carbonic acid caused by the suttion of the pumps. 
