2 2 2 D O C U M E N T S 9 2 , 9 3 J U L Y 1 9 2 0
holds.
So Stern is completely right.
With cord. regards, yours,
M. Laue.
92. To Paul Ehrenfest
[Berlin,] 30 July [1920]
Dear Ehrenfest,
Keep the case and bow there.[1] I want to buy myself new ones, so that the bother
of shipping is avoided. The bow that you are getting there is hardly an excellent
one. I believe I can buy both together for 700 marks. Do you actually want the sec-
ond violin? Decide completely according to your needs![2] Make immediate inquir-
ies about the damage so that the transportation insurance taken out by me can be
made liable for the repairs.[3] I am very enthusiastic about seeing you all again in
October, also about the prospect of seeing Langevin, who is very dear to me.[4]
I look forward to the discussion about magnetism at low temperatures. This top-
ic is now fully ripe for theoretical analysis in connection with the spec. heat of H2
and the Bjerrum spectrum of HCl.[5] Is pyrrhotite or any other, purer ferromagnetic
crystal known at low temperatures?
Affectionate greetings to you and everyone, yours,
Einstein.
93. To Konrad Haenisch
Berlin, 30 July 1920
Highly esteemed Minister,
From friends among my fellow colleagues I am aware that there has been [no]
budgeted chair for astronomy at the University of Halle since 1891, even though a
specialist, acknowledged by all astronomers as a capable man—Prof. Hugo
Buchholz—is working there as both teacher and researcher.[1] I consider it my duty
1
2
--m -
u3e
mu2
2kT
--------- -–
ud
0
ue
mu2
2kT
--------- -–
ud
0
---------------------------------------
1kT
2
-- - =
x3e–x2
xd
1
2
-- -
x2de–x2
–=
xe–x2
=