1 5 2 D O C U M E N T 2 2 5 S E P T E M B E R 1 9 2 1
superconductivity in a stationary manner. It cannot be individual electrons, how-
ever, owing to the electric incompressibility. So it must be electron chains formed
by atomic electrons passing through, quasi in single
These chains are, in the
state of superconductivity, continuous and undisturbed. The current is proportional
to the number of such chains, hence can only have discrete values. The level of the
current is of order of magnitude e (opt. frequency . electron charge).
If this is right, a superconducting coil does not respond to indefinitely small elec-
tromotive forces, thus it does not screen magnetic fields approached slowly enough
(that are weak enough not to disturb the superconduction). The expression “super-
conductivity” would then be misleading.
So all of you should do an experiment
(reaction of a closed superconducting
coil to weak alternating fields).
Nonsuperconducting coil; measure-
ment of the apparent self-induction of the
latter with weak currents. The superc.
coil could not carry under 10
4–10 5
Ampères.– Stronger magnetic fields destroy
Cordial regards to all of you, yours,
What do you think of this?
226. To Willi G. Münzenberg
Berlin, 3 September 1921
[Not selected for translation.]
227. From Otto Gäbel[1]
Berlin, 3 September 1921
[Not selected for translation.]
superc. coil
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