I^IE. G. GOEE ON THE PEOPERTIES OE LIQUID CAEBONIC ACID. 
85 
acquired the permanent position indicated by the dotted lines P, Q, R in fig, 5, when 
a piece of cotton-wool should be placed upon the stoppered end and saturated with ether, 
so as to distil off the liberated carbonic acid, and the application of ether be repeated at 
intervals until nearly the whole of the carbonate is decomposed and the stoppered end of 
the tube is full of liquid carbonic acid. If the experiment has succeeded well, a length 
of the tube, equal to 1 or 1|- inch, will, in cold weather, be filled with the liquid acid. 
By occasionally (once a day or less) applying the ether to the stoppered end of the tube, 
that part may be kept full, or partly full, of liquid acid for a long time ; I have kept it 
in this manner during several months. 
The most frequent cause of failure is clogging of the tube with sulphate of ammonia ; 
it is rarely that a leakage occurs at the stopper ; and the most frequent causes of explo- 
sion are, too rapid generation of the gas, and increased temperature of the atmosphere. 
It is highly advisable never to examine a charged tube without the wire-gauze inter- 
vening to intercept fragments of glass, and to use a large moveable screen of glass to pro- 
tect the eyes from projected oil of vitriol. Nearly all the explosions which occur take 
place during the process of generating carbonic acid, or within a few days afterwards. 
The proportion of tubes fractured or burst at different stages of the process is about one- 
thu’d. 
In some experiments, where electric sparks were passed through the liquid acid, two 
longitudinal cuts, of an inch deep, were made by a knife on opposite sides of 
the gutta-percha plug, extending from its smaller nearly to its larger end, before insert- 
ing it in the tube ; and two fine platinum wires inserted into the cuts and secured very 
carefully by means of a heated penknife ; the inner end of the plug was then coated 
with melted paraffin, the plug wetted with paraffin solution, and inserted in the usual 
manner. The wires extended nearly ^ an inch within the tube, and were imbedded 
for about of an inch next to the plug in paraffin, the remaining part served for the 
electrodes. (See fig. 6.) After inserting the plug and securing it by the binding wires, 
the whole of the outer end of the plug was freely coated with 
melted paraffin, to insulate more perfectly the electrodes from 
each other. 
In a first experiment, with the electrodes i^th of an inch 
asunder, and a sensitive galvanometer in the circuit, very 
feeble and variable conduction occurred with 30 Smee’s 
batteries ; but this was found to arise from absorption of a 
trace of sulphuric acid or saline liquid which had adhered 
to that end of the generating tube. In a second experiment, 
of an inch apart, and the liquid acid below 32° Fahe., not the slightest conduction 
occurred with 40 Smee’s batteries; and sparks from a Ruhmkoefp’s coil which passed 
through f ths of an inch of cold air would not pass through the liquid acid. In a third 
experiment, with electrodes about ^th of an inch apart, sparks from the coil, which were 
passing freely through -^nds of an inch of cold air, occasionally passed through the cold 
MDCCCLXI. N 
Fig. 6. 
the electrodes being i^otb 
