1 0 8 D O C U M E N T 1 4 8 J U N E 1 9 2 1
One of my very, very best friends, Prof. A.
Joffe,[1]
professor at the Polytechnic
in [St.] Petersburg, director of the Roentgenological Institute there, is currently in
England. [He has absolutely nothing to do with
politics.][2]
Because (despite being
invited by Lorentz, Onnes,
etc.)[3]
he couldn’t get a visa to Holland, I traveled to
Berlin to see and speak with him (and the optical physicist
Roshdestvensky[4]
),
whereupon—as you know—I stayed at your home.
Well: Joffe is a physicist of very, very high standing, let’s say, something of the
calibre of Franck
(Goettingen),[5]
if not perhaps even more original and multifac-
eted. While private assistant to
Röntgen[6]
and later in [St.] Petersburg, he made
very profound discoveries regarding the conductivity of electricity in quartz, NaCl,
etc. in its dependence on irradiation (unpublished since 1905 through Röntgen’s
fault!!)[7]
—But he did different types of things as well, in particular even in the last
3–4 years (!!!).
E.g.: By Millikan’s method he examined the magnetization curves of Fe and Ni
particles—found them to be absolutely hysteresis-free. [By contrast, particles of
iron oxide reduced in hydrogen: completely rectilinear hysteresis
loops.][8]
Or, e.g.,
X-ray analysis (with Laue’s setup, that is, visually on a fluorescence screen!) of the
reversible and irreversible deformations of NaCl
crystals[9]
(splendid result!!!!).
Then, e.g., an entirely new (very smart!) way to analyze the Richardson-Ein-
stein-De Haas effect, etc.,
etc.[10]
He isn’t just an excellent experimentalist but he is also uncommonly full of juicy
ideas.
And for all this, he is one of the finest, warmest, gentlest people I know.
What do I want?
1. That you immediately have him come and see you, if it’s possible for him
somehow, wherever you happen to be at the moment in England. Prof. Joffe c/o Mr.
D. Filitz, London W.C.1, 133 High [St.], Museum Station, Cable address: Aba-
hafi[l] Westcent,
London.[11]
(Summon him by telegram
perhaps[12]
[Address on
letters to your wife.], then you have the least trouble.)—And let him tell you about
a couple of things. Force him to respond promptly, because of his own accord he
reacts very hesitantly. Remember that he’ll be going back to Russia under very dif-
ficult working cond[itions].
2. Recommend him, please, in my name to the young
Bragg[13]
and—if it’s pos-
sible—to
Rutherford.[14]
It is very important for him—in connection with the
planned (very smart) research by him, to be able to speak with the two of them in
quiet discussion. N.B., with an interpreter, because although he can speak German
very well, he knows virtually no English. Joffe needs absolutely nothing besides an
exchange of ideas!