Institute for Theoretical Physics
University of Munich
May 22, 1926
Dear Dr. Noyes,
We have been getting along nicely here; but we miss Pasadena, for everything so different from what we had become accustomed
to. Even in the Institute, things are done differently; for example, the seminars are devoted to formal presentations of new
papers, without the invigorated discussion which we are accustomed to having; and the research problems of the men themselves
are not discussed or at any rate have not yet been discussed. Instead it seems proper to do everything through Professor Sommerfeld,
who holds private discussions with the men here concerning their researches.
Yesterday I went with Professor Sommerfeld to the Deutsches Museum, where he suggested some changes in the exhibits on the
structure of matter and on optics. On introducing me to one of the officials he said, “Dr. Pauling is from America, but he
speaks very good German.” Despite the fact that I know he was joking, I was pleased, for the remark is untrue enough to be
flattering. The Deutsches Museum is a marvelous place, with an immense collection of exhibits, models, apparatus, etc; and
it is kept up-to-date through the efforts of the leading scientific and technical men. I saw, for example, a model of a Flettmer
rotor, which really worked: the wind was supplied by electric fans, and the rotor, turned by an electric motor, was on a little
car which ran back and forth at right angles to the wind. In the section on the structure of matter there are models of the
hydrogen atom and the hydrogen mol-ion, of a number of crystals, of solid solutions, showing atom-for-atom replacement, of
metals, showing plastic deformation through slip along glide-planes, and models of a number of organic molecules, including
a complicated dye and bees-wax, which looks like this- /\/\/\/\/\/\/\/\/\, and is about four feet long. There is a fac-simile
reproduction of Liebig’s laboratory, and of an alchemist’s laboratory, and of others. Of historical interest are samples of
the original specimens of most of the elements discovered in modern times; Sancke’s original space-group models; Van Hoff’s
original tetrahedral showing stereo-numerism; and many other things. I am glad that we shall soon have in America a similar
I am enclosing an advertisement regarding crystal models. I now think that it would be unwise for us to make these models
at the Institute, since Selmayre, who is Sommerfeld’s mechanic, makes them so cheaply. I do believe strongly that we should
have a large number of them; for I think it will continue our work in crystal structure. As far as I am concerned the models
will not be needed for a year and a half, and unless Dr. Dickinson will want them for next year it might be well to wait awhile
before bringing them, for Selmayre said that he might reduce his prices, which are now about $4 per model. I have checked
about twenty-five, which would give us a good collection of these handsome and well-built models, at a cost of $100.
Sommerfeld and Grimm have written an interesting article in which they conclude that the shared-electron bond is present
in a number of crystals, including AlN, BeO, ZnS, AgI, etc. I agree in all cases but ZnS and AgI, and I am doubtful there.
They have shown thermodynamically that AlN does not consist of Al+3 and N-3 ions. Dr. Niesseu, a Dutchman here on an International
Fellowship, has made some calculations regarding shared orbits. I think it probable that I shall make some later, too. Recently
I have been studying paramagnetism, and have found a new derivation of Langevin’s law (or Curie’s law) for crystals. However,
I just recently found a paper by Cabrera in which he qualitatively and somewhat vaguely suggested the same thing, thus taking
the edge off my work. Yesterday I told Dr. Sommerfeld of my work on the quantum theory of the dielectric constant of hydrogen
chloride, and he was interested in it, especially in the part (as yet unpublished) concerning the action of crossed magnetic
and electric fields. He said for me to begin work immediately on the problem of fields of any strength (I had before considered
one to be much stronger than the other), for he thought the problem to have great theoretical as well as practical interest.
He said that he would present the results next month in Zurich at a congress on magnetism called by Debye. I shall accordingly
have to work to have results by then.
noticed in Physikalisde Zeit, 27, 165)1926) an article in which E. Ott applied the powder method to determining size of unit
and hence an upper limit for the molecular weight and so the amount of polymerism of some organic compounds. Then later in
Naturwissiuschaften he reported a similar research on rubber. However, no one has yet reported a true molecular weight determination.
I am accordingly anxious ot learn how Kirkpatrick has turned out in his work on K3Ni(NO2)6. I still think that it would be
a fine thing to make a molecular weight determination on insulin, in case large enough crystals could be obtained.
Dear Dr. Noyes,
We are going Wednesday with some boys on a trip to the Bavarian Alps. We shall have our first experience in real mountain
climbing. I have an ankle which is a bit tender, but I shall wear proper shoes.
Perhaps you will be interested to know that I can understand German conversation a little now, and that I can even say a few
things. Linus does nicely.
We are both very well and happy, and Linus looks much much better, which pleases me.
Mamma writes that Linus Jr. walks all around and that he is extremely well and happy.
We are enjoying Munich very much but we shall be happy to get back and Linus gets really lonesome for the Institute.
We have seen several operas which were excellently done. Fortunately the price of tickets is well within our means.
We saw Mr. Anderson and Mr. Ewing quite often when they were here. They too are enjoying their trip.
I trust everything is going nicely with you and the Institute.
Ava Helen Pauling
P.S. I study my German grammar daily and attend all of the lectures. One of the German boys said that including myself there
are five Americans in the Institute for Theoretical Physics.
I fear I don’t lend much to the department.
Ava Helen Pauling