3 9 6 D O C U M E N T 4 0 1 D E C E M B E R 1 9 2 4
After we saw that solid CO2 leaves behind strong charges when vaporizing, we
examined the charging rate as a function of time. Our suspicion was confirmed: It
is a dirt effect formed by the oily residue, because the effect rapidly increases: the
less CO2 there is left, the more concentrated the oil is. The effect is so great that its
elimination by purifying the CO2 appears to be impossible.
I have now tried to vaporize water in a vacuum. But it is impossible to obtain a
sufficient vaporization rate without bubbles forming.
After these failures, I gave up producing ion-free gas directly. Consequently, all
ions must be removed form the gas inside a capacitor. If one wants to measure the
effect of the generated gas by this arrangement, one must connect the whole capac-
itor and the voltage battery to the electrometer, that is, isolate it. This now leads to
very large capacities.
I therefore preferred to condense the purified gas and determine the charge that
occurs in the process.
This leads me to the following apparatus:
Gaseous carbonic acid is taken from a pressure flask. It passes through a nozzle
where ions are in any case generated. These and all the ions coming out of the pres-
sure flask are now captured inside a large capacitor. (The gas sweeps through the
interstice between 2 brass pipes [7 cm] and 4 cm in diameter and 2 m in length.)
Between both we can apply up to 2,000 volts.) Exiting from the capacitor, the gas
arrives through a short conduit of Ø = 15 mm, the last piece of which is made of
quartz, in the condensation vessel. This vessel holds 4 ½ l[iters] and is filled with
pumice soaked for a long time in concentrated KOH. Trials with smaller vessels
have shown that the large vessel can absorb, in any case, 100 g, probably 200 g
CO2, within a few
minutes.[2]
Prior to the trial the entire apparatus is evacuated,
which raises the reaction rate very significantly. The vessel is connected to the elec-
trometer and is shielded from the exterior air by a sheet-brass container (at a dis-
tance of 2 ½ cm). Here, the arrangement in rough outline: