D O C U M E N T 5 7 F E B R U A R Y 1 9 2 2 7 7
You can help in this better than anyone; you would be doing a great service for
your colleagues in Germany and in France and, above all, for our common
You will find here the best of welcomes; your work and your personality are
equally agreeable here. You will also encounter an audience of students prepared
to follow you, in addition to a public at large desirous of getting to know you. My
teaching here at the Collège has been concentrating exclusively on the theory of rel-
ativity for many years
The Michonis Lectures have not been devoted to physics since Mr. Lorentz came
You alone could renew this link, following the horrible years of the war.
You will hold any number of lectures you please and have them as interrelated
as you please. Five or six, for example. Depending on the subject you choose. You
will receive for it a remuneration of 5,000 [francs].
It is desirable, so that the audience can follow you, that these lectures be held in
French. I think there should be no difficulty in that. If you would like to draft a text
in advance, I will translate it for you and you could read at least a part of it if you
experience any difficulty.
We would be very happy if you could come before the month of June and if your
first visit to Paris were made exclusively for scientific purposes. This will be the
best manner of working toward the peace we all want.
As soon as I have received your affirmative reply, the administrator of the Col-
lège de France will send you an official invitation.
Our friends here join me in urging you very enthusiastically and telling you that
we shall do our utmost to make your sojourn as agreeable for you as we can. I
myself have fond memories of your visit in 1913, not counting the other circum-
stances in which we saw each other again
In most affectionate devotion, and do send me a positive response very soon,
57. To Paul Ehrenfest
[Berlin,] 20 February 
In that case, of course I’ll come for the second half of April, and generally twice
a year. You generally do know how much I like being there. You did not have to
waste so many words on
I am working with Grommer on quanta in hydrogen.
We have already been able to prove that a quantum influence is there; now it still
has to be decided whether or not there is zero-point energy. Probably yes according