D O C U M E N T S 1 2 4 , 1 2 5 S E P T E M B E R 1 9 2 3 1 1 9
124. To Elsa Einstein
Leyden, 25 September 1923
After very remarkable wanderings I arrived here yesterday at midnight; and after
overnighting at the “Blue
and the children this morn-
ing in the best physical condition. Tomorrow Eddington is also
very nice in Bonn but the people there are being terribly
obliging, friendly man from the Fr[ench] authorities turned out to be—a Jew and
Without him the whole convention might not have been able to take
In Bonn I additionally made the acquaintance of a very nice Jew, Rabbi Kohn,
who had once earlier left Berlin in a fuss and had his own
really is a splendid fellow, despite his muddleheadedness. I hope all of you are well.
As far as I’m concerned, you don’t need to stand guard.
Warm regards to all from
125. From Hermann Mark
[Berlin,] 28 September 1923
Today I would like to convey to you, Professor, the results of the first experi-
ments, even though they are certainly just of an entirely preliminary nature, in order
to ask whether you, Professor, agree with the manner of execution, or whether
something has to be
The X-ray tube is a glass Coolidge tube with Rh anticathode; it operates quite
evenly but has the disadvantage that one may only load it continuously up to 2 mil-
liamperes. This is, of course, terribly little, and I would very much like to have a
small piece of sheet Rh in order to be able to insert it in one of our tubes; then one
could easily send 20 milliamperes through. Unfortunately, I haven’t been able to
get any Rh; perhaps it would be possible for you, Professor, to obtain such a thing?
For the time being I began the experiments thus.