D O C U M E N T 4 0 1 D E C E M B E R 1 9 2 4 3 9 7
[3]
“pressure flask”
[4]
“to the pump”
[5]
“contact pin”
I believe that the isolation will be quite good. I have only two solid insulators:
the amber piece that the electrometer thread hangs from, and the SiO2 pipe from
which the absorption vessel is suspended. This quartz pipe will be heated from the
outside before the experiment by having the neck of the shielding container fitted
with a heating coil. The arrangement is protected as well as possible against an ion-
ization current in that all air masses are situated within strong fields. This is the case
inside the electrometer, anyway, because the two plates generate the necessary
field; two pins of + and –100 volt suffice for the grounded space above the elec-
trometer. The shielding vessel consists of 2 halves, which are likewise charged +
and –. The middle of these auxiliary tensions is “grounded,” i.e., connected to the
electrometer housing. With this arrangement, I get the result that the ions sponta-
neously developing in the air always go along the same path, independently of
whether the vessel and the electrometer thread have a few tenths of a Volt more or
less than the “ground.”
If one doesn’t do this, the air acts like an ohmic resistor, as the slight potential
difference between vessel and protective casing produces an unsaturated current,
whose intensity and direction are proportional to the potential difference between
vessel and protective casing.
The experiment should go like this:
The electrometer is charged by the contact point and the small potentiometer un-
til the thread reaches the edge of the scale (alternately right or left). Then a sponta-
neous motion of the thread for the different potentials is examined (a few tenths of
[3]
[4]
[5]