Institute for Theoretical Physics
July 12, 1926
Dear Dr. Noyes:
We were very glad to hear from you, and to know that you are getting along well this summer. The news regarding people
at the Institute was most welcome, too. I had worried a little about the draft I sent you, for a accidentally ported it without
registering it, but it arrived safely.
I appreciate very much all of the work you have done on my Debye-Hüchel paper. Your changes help the paper very much.
I have carefully revised Page II, for it seemed not to be clear even to me; I think the new version, enclosed in this letter,
is much better. In addition I feel it desirable to make the following changes:
1. crossed out
2. To replace B by Bo on all pages before P. 11
Also once each in Tables I and II,
3. Leave B as written on P. 14, but write instead of the last sentence
“In Equations 21, 22 and 23 B2is equal to 4πe2/KhT Σ(niZi2);
for in the first two no differentiation is made between √Σ(NaZi2) and √Σ(NiZi2), and in the last equation √Σ(NaZi2)
has been replaced by √Σ(NiZi2) by introducing the correction factor S.
I hope that my explanation of the use of an averaged value of √Σ(NaZi2), independent of r, will be clear to you. It is true
that the arguments I used here are very complicated and not too straightforward, but I think the second correction factor
is really required, and is of approximately the form I have given it. In an earlier draft of the paper I gave the methods
by which I obtained the factor ½, and showed it to not depend on the concentration, but I found this to be only confusing,
on account of its length and complexity. If you still have this earlier draft, you might re-read this part of it (especially
the footnote regarding the independence of y on r) and incorporate part of it, perhaps: I would like not to have the present
P. 11 changed except by addition, however.
If Prescott prepared any pure ZrC, even in powder form, think it would be worthwhile to try to determine its crystal structure;
for it might be of importance in regard to the theory of tetrahedral-type crystals, developed by Grimm and Sommerfeld (you
received a reprint of this, unless it went astray). Crystal interpretation is difficult: I am hoping to be able to do something
on it soon. I have talked with Fajaus, and also with Knorr, who has some interesting cases of non-polar compounds- metallo-organic
ones. I think it might be worth while to prepare a review of the evidence regarding the dynamic model of the non-polar bond.
I feel that Grimm and Sommerfeld’s theory, somewhat expounded, may get support from many crystal-structures; Huggins work
is important in this connection; his only difficulty being that he wanted al crystals to be of this type. In this regard,
have you thought it worth while to buy crystal models here? If so, I think perhaps Selmayr should start pretty soon and make
them during the winter semester, while I am here, for I’d like to have some of them made in a special way. They seem to me
to be worth having.
Hansfeld, who is a physical chemist as well as a physicist, is going to stay in America at Johns Hopkins. Professor Sommerfeld
was sorry to lose him.
We went to Zurich June 22-26 for a congress on magnetism, called by Debye. Professor Sommerfeld presented my work on the influence
of a magnetic field on the dielectric constant of HCl; later W. Pauli Jr. showed me that probably the effect definitely predicted
by the old quantum theory would not be predicted by the new quantum mechanics. The fact that Matt Smith did not find the effect
is accordingly good evidence against the old quantum theory and for the new. I am now working on the new quantum mechanics,
for I think that atomic and molecular chemistry will require it. I am hoping to learn something regarding the distribution
of electron-orbits in atoms and molecules.
I talked with Professor Ewald in Stuttgart about crystal structures. He asked me particularly if it would not be possible
for us to publish such papers regularly in the Zeitschrift für Kristallographie. Wyckoff, Bragg, and others are now doing
so. He does not want a paper to be represented there, as Wyckoff has done, but wants an abstract of it only if it is published
elsewhere. Papers of purely crystallographic interest should be published there in full, I think. He would like us to send
him, say once a year, a review of our own crystal work for publication also. He said that perhaps in a couple of years they
would publish papers in their original language; at present he is willing (not anxious) to translate them.
I should like to have your advice in regard to my publishing papers during this year. Do you think I should publish in the
American journals? I prepared a paper for the Zeitschrift für Physik; but now I have to revise it, including the new quantum
mechanics. The German publications seem better than ours in one way- in the Zeitschrift für Physik, for example, papers are
often published in six weeks after their receipt. Also, would the Institute like reprints of my papers, and if so, how many?
I am sure that you will enjoy spending the summer in your new house at Balboa. I send best wishes to Professor Sherrill.