1 1 6 D O C U M E N T S 1 1 9 , 1 2 0 S E P T E M B E R 1 9 2 3
119. From Hermann Mark[1]
Dahlem, Berlin, 16 Faraday Way, 19 September 1923
Highly esteemed Professor,
My most cordial thanks for your kind postcard, which I hasten to answer. Unfor-
tunately I was not yet able to perform any actual experiment because the procure-
ment of the necessary materials (Rh, Mo foil) cost much
time.[2]
Now, however, I
am getting a Coolidge tube with an Rh anti-cathode from Hamburg. Nowhere else
in all of Germany could one be obtained; I also already have the Mo foil. Accord-
ingly, I hope to be able to perform the experiment next week.
In the meantime, I found two other papers concerning this topic:
One by P. Debye in the Phys. Ztschr., in which a quantum theory of scattering
analogous to Compton’s
theory[3]
is
developed,[4]
and the other by Jauncey and
Eckart in the latest issue of
Nature,[5]
where the authors conclude on the basis of a
survey of hitherto published material that a change in wavelength certainly does not
occur upon reflection off crystals because, if it had Compton’s magnitude, it would
already have been noticeable. However, this paper just considers the measured in-
terference maximums and not the diffuse radiation, nor does it take into account the
bonding strength of the individual electrons.
As soon as I have any news to communicate, it will happen immediately; I hope
that will soon be the case.
With best wishes and most devoted compliments, I am, Professor, ever gratefully
yours,
H. Mark.
120. To Elsa Einstein
Bonn, 21 September 1923
Dear Else,
Now the physicists’ convention is
over.[1]
It was an interesting conference so I’m
glad about having come here. Laue wasn’t here; peculiar fellow, he doesn’t come,
after having written to me like
that.[2]
It’s very nice at
Pflüger’s.[3]
He sends you his
regards. Yesterday we visited Duisberg in
Leverkusen.[4]
The plant is as big as a
town, just the factory building, so the transport of persons inside the plant is done
by railway. Such a materialization of the human intellect is astonishing. I was im-