Institute for Theoretical Physics, Munich,
April 25, 1926
Dear Dr. Noyes:
We have come to the end of a very pleasant trip, and I am glad; for even though Italy is wonderful, and everything was
new to us, traveling becomes tiresome. Moreover, I became very anxious to get back to work after nearly two months of idleness.
We enjoyed the shoretrips at Madeira, Gibraltar, and Algiers very much. We saw everything; indeed, after walking
for an hour through the Arab section of Algiers we were glad to see even Naples, which is itself not spotless. We walked about
two-thirds of the vertical distance up Vesuvius, instead of going with Cook’s on the rack-and-pinion; the last part, up the
cone, which I believe you climbed, is now provided with a cable-car, in which we rode. In climbing the first 2400 feet up
we walked about seven miles along a trail up an old lava-flow. The mountain performed well for us, grumbling and spouting
out red hot rocks.
We were twelve days in Rome, and seven Florence. We like visiting galleries, and have spent much time in them. We were
somewhat disappointed in the Roman ruins; for after the beautiful isolated temples at Paertum Rome seems a terribly crowded
place. We were in St. Peter’s on Easter, and saw Anderson and Ewing there. We haven’t seen them since leaving Rome, but we
expect them now in a few days. We liked seeing St. Peter’s and some other wonderful churches; but we haven’t sufficient liking
of the structures in general to visit the myriads mentioned by Baedeker.
Dr. Robertosn and his wife came to see us yesterday. They were returning to Gottingen from vacation spent in Austria
and neighboring countries. We were glad to see them, and they us. If his fellowship is renewed for another year in Europe
he proposes coming to Munich for the Winter semester.
Tomorrow Professor Sommerfeld is going to suggest a problem for me – perhaps a small introductory one. Apparently that
is the European system; I, perhaps undiplomatically, mentioned tentatively that I should like to work on a certain problem,
but he didn’t give my suggestion much heed. I feel that I shall be satisfied, though. He and Grimm have published a paper
in which they discuss very specifically and satisfactorily certain cases of crystals in which atoms are connected by two electrons
on orbits about the two nuclei, and Dr. Niessen, from Holland, a Fellow of the Rockefeller Foundation, is just publishing
the first calculations regarding such orbits. Probably my problem will be in this field. I shall learn from it, too; for it
is rather difficult mathematically, and I couldn’t have done what Niessan did by myself, and perhaps not even with advice.
Moe had said in New York that our money would await us here on our arrival. However, we found yesterday only a letter
stating that we should receive $2500 and $500, and that the first quarterly payment would be sent on receipt of a letter of
acceptance from me. Fortunately we are not inconvenienced too much; for although we were tempted to stay longer in Italy,
and so spend more money, I became anxious to begin work and we came to Munich on the 22nd with all of our money not spent.
I notice that Elliot Adam’s paper was published in the March journal. Possibly mention of it should be made in a footnote
in my paper, since I propose an alternative explanation of the different results of Milner and Debye and Huckel. If it isn’t
necessary to mention it, so much the better.
I shall write to Dr. Dickinson soon and ask him about the crystal-structure researches, especially Kirkpatrick’s,
Yost’s, and Day’s.
We hear that the baby is getting alone very well in Portland, having long ago completely recovered from the cold he contracted
on the train. We shall be glad to see him again when we return.
Ava Helen and I send our best wishes to you. I shall write again and tell you of my research, and of the Institute when
I begins operation.