A flame placed between two small disks on the machine bends toward the
negative pole, becomes widened, and, at a certain point of electric
intensity, commences to vibrate and oscillate, exhibiting a peculiar
stratification. Since these phenomena are also least observed in flames
rich in oxygen, it appears to be a general law that carbon and hydrogen
are more strongly attracted by the negative pole, while oxygen is
more attracted by the positive pole, probably like in all polar
differentially attractions, in consequence of a peculiar unipolar
conductivity of the substances.

The return motion of the flame the author explains thus: The point
of the flame loses more electricity by influence than it receives by
conductivity. A paper strip fixed at one end to a large ball shows
similar movements when its free end is pointed and made conductive.
Why principally the negative flame returns may be explained in two
ways--either the point of the flame loses much by radiation, or the base
of the flame is a bad conductor. The former explanation would agree with
the experiments made by Wiedemann and Ruhlmann, the latter with Erdman's
theory of unipolar conductivity of flames. This theory is still further
supported by the resistance on the negative electrodes noticed by
Hittorf, which almost explains Erdman's experiments, because if negative
electricity enters a flame with greater difficulty, then positive
electricity must leave a flame with difficulty.--_W. Holtz, in
Wiedemanris Beiblaetter to Poggendorfs Annalen._

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