(^84) THE THEORY OF IONIZATION
distilled water until, when they are immersed for 10 seconds or
more, no sign of a glow is seen in the lamp filament. To illustrate
the necessity for this precaution, first immerse the electrodes in
hydrochloric acid solution, then, without rinsing, immerse them in
a vial of pure water; the lamp will glow very distinctly.
X
0 0 Q P
*- Copper
FIG. 17
/Mercury
—PlatinumFine
Wire
- Electrical Conductivity, (a) Pure Substances. Note that
the lamp does not glow when air fills the space between the elec-
trodes. Then raise successively between electrodes B distilled
water, alcohol, pure acetic acid (labeled "glacial acetic acid"),
and place in contact with electrodes A lumps of any two dry
salts found in the laboratory, for example, common salt, NaCl,
and blue vitriol, CuSO 4 -5H 2 O.
What general statement can be made about the conductivity
of pure non-metallic substances, gaseous, liquid, or solid?