138 Scientific Intelligence. 
centimeters in diameter, nig filled with liquid sulphurous acid. 
Under the influence of a good vacuum the temperature of this 
so rapidly sinks to —65°, and even to —73°, the extreme limit 
SThioegh this tube of eke as acid passes a second smaller 
tube (s), of six pigeon diameter, and the same length as the 
envelope. These two tubes are lonil by a common base. 
In the central pre is retained compressed sarionls acid pro- 
duced by the reaction of hydrochloric acid on Carrara marble. 
This gas, being dried, is stored in an oil gasometer (@) of one 
cubic meter capacity. 
t a pressure of from four to six oe oo carbonic acid 
easily liquefies under these circumstance The resulting liquid 
is led into a long — tube (B), four cma in jength and four 
ne more in diamete 
o pumps, P pes ae , coupled together like the first, exhaust 
dartonls acid either fro om ‘the penn? (c) or from the long tube 
lowest obtainable temperature. These two long tubes are con- 
nected by the ends of the carbonic ate tube, consequently oo 
ore tube extends about one meter beyond the other. I hav 
rved this portion downward and given the two long tubes . 
slightly inclined position, but still very near the horizontal, as I 
have shown in the accompanyin wee 
cine small central tube is curved at a, and screws into the neck 
howitzer shell, c, the ane “of which are thirty-five 
pailinietans thick ; the height is is ee centimeters, and the 
the 
up, and introduced into the shell perfectly dry. When the double 
circulation of the sulphurous and carbonic acids has lowered the 
