D O C U M E N T 1 7 3 O C T O B E R 1 9 2 0 2 8 9
A sketch is attached:
Distance between the magnets and the sphere 5 .
It is thereby revealed that the sphere has preferred positions
that are caused by irregular thicknesses of the sphere wall or by
varying conductivity of the aluminum sheet. A repetition of the
experiment with an Al sphere, carefully machined inside and
out, of 2.5 wall thickness was very successful. Preferred positions very small.
The sphere’s settings between the rings of magnets very clear.
I am now having a new experiment prepared with a sphere of 220 and
built-in gyroscopes, hoping that it manages to catch the lines of force in such a way
that the 3 gyroscope bodies do not cause preferred positions; for that purpose, I
have arranged two more iron sheets inside the sphere.
In any event, the thing looks very hopeless. As of now, I have not registered any
patent yet; still want to wait and see what other surprises and problems the new ap-
paratus still has to show for itself. Then the firm A[nschütz] and Co. will contact
you and send you the patent proposal and solicit your approval.
The second trial with the heated copper cylinder has yet to be done, because I
am still waiting for a pure copper rod of 50 diameter, which has already been
I first provided for frictional heat, by the simplest arrangement, since I
then have no worries about power connections [on both sides] or the like. I shall
report to you about the experiment that my cousin Schuler is going to conduct dur-
We are in the act of dismantling our tents and moving southward; the cold is
chasing us away. It would be grand if your path led you to Munich and brought us
the pleasure of your visit. And we are quite certainly counting on a hopefully very
long visit from you and your wife next summer. Then I am going to demonstrate to
you the hopping sphere in natura.
With most cordial greetings, yours,
I too am looking forward to next summer, which promises to bring a visit by you
and your wife. Your surrogate mother,
173. From Ilse Einstein
[Berlin,] 10 October 1920
Yesterday evening I received your
thanks very much indeed. I would
have liked to write you properly, but now it’s 11 o’clock at night (Sunday) and I’ve