1

Copenhagen 27.10.1928.
Dear Nishina,
Just a few lines accompanying the manuscripts, which I hope willreach you in time. I am just copying the formula in the copies for z.
f. Phys. Thank you for your kind letters. I hope that I have understoodsuggestions about changes properly.

You can see how you like thepassages 工 put in. If you write me before the proof comes 工 shall ofcourse be glad to put in any change you might think desirable. The
difficulty was the eigenfunctions in the presence of a magnetic field, a
point which 工 think is not completely cleared up yet, though the form inwhich the degeneration of the free electron is now treated in the paper
would seem to be unambiguous. Therefore the eigenfunctions you haveused in your paper are not so simply as we thought connected with theSpin， but this has no influence on your results, only the sentenceswhere spin comes in could not have quite the definite form you gavethem. Now you can see what you think about the whole thing.
And then I want to thank you for the time we have been together andsend you the best wishes for your future. I need not tel1 you that weshall often miss you.
The kindest regards from all of us.
n
V4・
l
le

e−
rk
e
cr
na

s

k
s−−s
n
v

E
U
O

Y

P.
s. Bohr sends you his kindest regards and asks me to tel1 youthat it has occurred to him that you perhaps might wish that a document
like that he sent you yesterday was addressed directly to the Directorof your Institute or to somebody else. 工f so, would you perhaps let him
know how it should be addressed and what changes in content or form you
might suggest.

2
Copenhagen 2.12.1928
Dear Nishina,
Thank you for your kind letter with the manuscripts. The reason
that 工 have been so slow in answering is that I wanted to send you
proofs, which had arrived a little before your lette工， in final shape.
I hope that you will find that the changes agree with your suggestions.
It was very helpful that you wrote down everything so carefully.

The

only important change was one found by Chr. M￠1ler, who on Boh
工・sproposal went through al1 your calculations with the help of the papers
you left with me. We thought that you would be glad for this since you
could not yourself see the proof; and unfortunately I was too busy to doit. The change in question comes from that you had forgotten in using
formula (7) of your paper for the calculation of the intensity of the
doubly scattered radiation to take the change of frequency during thefirst scattering into account, a thing one would easily forget. As you
will easily see, the effect of this is, that (3 in (7) has to be taken
equal to o
<
/
(l+o
）
く.

The final formula, however, is not very different

from your original formula, and all your general conclusions are valid.
工 agrees somewhat better with Lukirsky s measurements.

As to the spin difficulty it was this: In the paragraph about the
eigenfunctions in the presence of a magnetic field, which I gave you toread a few days before you left Copenhagen, I had tried to prove, thatthese functions for arbitrary velocities were those where れ＝Oす戸respectively.

andThat this is wrong would follow・from ourconsiderations in the country already, but in the meantime I had
forgotten some of our conclusions ‑ for instance that the solution in
Bessel functions was only valid for p3=0‑

and only the last day I

found the error in the argument. This had no very close connection withthe difficulty regarding spin, which we had been discussing that3

afternoon; It occurs to me now that you must have thought so, and that
this may have made it difficult to you to see the point in question. I
think that I came to reconsider the question partly due to our
discussion partly due to some remarks of Bohr on the general problem ofspin. Since for our purpose the possibility of actually magnetizing(or polarizing) electrons ‑ a problem, which has proved to be rather
difficult to solve, Bohr and the whole laboratory have been interested
in it since that discussion on Oppenheimer s paper, which you took partin
was not immediately essential 工 have limited myself to try togive a proper treatment of the degeneration in question. The result is四the new §.
2 of the paper. 工 found this way of treating the degeneration
rather covenient, since it gives a simple way of finding two independent
eigenfunctions for each set of energy and momentum. There are, however,an infinite amount of other eigenfunctions, for instance our solutions

サ1=0， ψ2=0. But you must not forget that our argument for regarding
them as proper eigenfunctions was that we believed that these, apartfrom the transition to Bessel functions, would be the eigenfunctions in
the presence of a magnetic field. In fact，工 did not feel certain thatOU
工intensity calculation was correct until I had derived all our dd,

ds etc. relations by means of the new functions, which I have called＊ ＊u , v . At present I am inclined to think that one could have beencertain of it. But I do believe that the argumentation is easier when＊ ＊we make use of u ,v . Another point, where I think there is some

progress since you left, is the way of calculation indicated at the endof p.13. I rather believe that the whole intensity calculation would bequite a bit simplified if we tried to use this procedure from the very
beginning, but I have not had time to look at this.
We are a11 very eager to hear from you soon, both about yourexperiences in America and about your arrival in Japan. It was very
good news you sent about the interest for our work in Camb工idge.
Ishall also write to you now and then, though writing letters is not my4strongest side. My wife is fortunately quite well again. She and allof us send you the kindest regards and many good wishes for Christmas
and the year 1929.

v
a

le
−
e
−
rk
e
c
z
na

n

LA

o

．
ム

SS

s
z

u
o
y

P.S. 3.12.1928 Your Nature Note has just appeared. We intend tosend a short note, where the mistake in the formula is corrected. As
soon as it is written I shall send it to you, and you may even get timeto have it changed. I don't know if what I have written in this letter
about the spin question makes it clearer to you. I should be glad tocome back to this point if you have still any doubts. When thediscussionsabout spin going in the laboratory have led to more definite
results I shall be glad to tell you about them.

Copenhagen 23.1.1929
Dear Nishina,
As I wrote to you, M￠ller found a small mistake in yourcalculations and unfortunately your Nature letter appeared just a little
too soon to have it corrected. Bohr and I have been talking of a note
to Nature where the result is put right and I send you a few lines justto show you what we have been thinking of. If you find they will do forthe purpose we thought that time might be saved if you let us send themin.
In that case you need only send a telegram (slow message) with theword agree to Bohr, Blegdamsvej, Copenhagen. We shall then keep the
proof until we have a letter from you with your comments.
Our papers in Zs. f. Phys. have just appeared and I hope to have5

reprints one of these days; then yours will be sent inunediately to
Tokio. It has been very nice through pretty post cards you have sent us
to follow you工 1ong journey． 工 have just received the one from Tokio,
and I am glad to hear that you are well at home. We had a very pleasantChristmas vacation, first in Aarhus and then in Sweden.
you from everybody.

I shall greet

VA

︑i

−

en
r L
ee

−
ム

nk

cI

s o−
s
r

u
o
y

In a letter to Nature (December 1, 1928) I have given aformula for the intensi七Y of radiation scattered at right angles
first by one and then of the change of pregnancy of the radiation
during the first scattering. When this mistake, which has beenkindly pointed out to me by Mr. Chr.M￠ller, is corrected theformula of the former letter is replaced by

e
s
T
.
f
<
X
.
2(
2十 4
α ＋ 3a2)¥
一 わが csin2
θ ＋2(1＋ αl8,.2r1 一~一寸~
(
1+2
α）. l
)
2(
1+2
α｜
）

工−

Due to this, the comparison with the measurements of Lukirsky
comes out somewhat differently. Thus for 8= 0。the intensity of。

5.3毛 insteadof 6.5も of the intensity at 90 , when the wavelength。

is assu
med to be 0.085 A,and agreement with Lukirsky s result
would be obtained with a wavelength of 0.13 Ainstead of 0.14 A.
工nstitute of Physical and Chemical Research

Tokio

February 1929
Y. Nishina

6

n2

︐

dQJ

a
0 ・
︑i ・lauτ
ak
c
o 中 −

vaC

1
−

sh

工 CK

hro
paq
en
gム S O
oeH
eR
tl e
uam
t
co
i
q
tm
− a
se
m
nn
・ o

1
ゐ

Dear Professor Hevesy,
工t was with great delight and interest that I read your kind letter＊of the 18th November upon my arrival here through America at the end of
December. Since then more than three months have gone without my having
answered to you. Your letter as well as all other letters of my friends
have been lying on my table during whole this time and I have had a very
bad conscience. At last I have time to‑day to write this letter to you.
The reason why I have been unable to write is that I have had too muchto do. Let me tell about it.
First of all 工 have had to deal with a good deal of family affairs
which have accumulated during last eight years and the duty of which I
have neglected to do. There is an endless chain to follow. Then I have
had to fill up the gap both abstract and concrete, which has been formed
between Japan and myself during my long absence，工 have had to adjust
myself to the new conditions of life. All these things have taken andare still taking an incredible time for me. Next thing on which I have
had to spend a good amount of my time is the lectures I have had to giveon current problems in physics. To prepare such lectures is one thing
in itself, but to write them down in a complete form for publication isanother thing which is not so easy. Last thing which has taken my time,
has been a marriage question and its consequences. 工 have had to marryabout 5 weeks ago. You will perhaps be surprised that such an important*See Publication No. 17， G. Hevesy ‑ Y. Nishina, Correspondence
1928‑1949， p.l.

7affair of life has been carried out in such a short time. It is nearly
impossible from Western view‑point, I myself did not know at the time of
my arrival that I should marry in such a short time. But each country
and even each family has its own custom and tradition and I am after alla man who was born in Japan, and according to the advice of my fa
mily
and friends， 工 decided to marry a sister of my intimate friend here andhad the wedding on the 23rd Feb.

At the same time 工 rented a small

house in order to form my home． 工 have had to furnish and arrange thishouse，工 have had the first experience of running a house. All thesehave taken whole my time. You will see why I have not written a line toyou so long.
Tokio has changed very much since the great earthquake of 1923, somuch in some places that I could not recognize them at all.

As to myadjustment to the Japanese conditions in the daily life, it has been
going on quite all right.
工t has not been so bad because I have afairly elastic adaptability to new conditions. Owing to the above
circumstances 工 have been unable to get into physics at all,but I hope
to do so soon.
Takamine, and Sugiura work in this Institute. Takamine has beenill, but has recovered and will soon begin his work. Kimura is at the
University here, we do not see each other very often, because I havebeen so busy; he seems to be all right and is continuing his work which
he did in Copenhagen. Every time we meet, our conve工sationcomes to you
and your family whomwe miss very much.
In your letter you wrote about the possible change of yourposition. How have you decided ?

I can understand how difficult it

must be for you to decide between two good alternatives, but it is goodthat you have two good ones and not two bad alternatives.
How are you and your family ?

I heard that you have had a very

8severe winter all over in Europe. I hope all of you are all right andare now enjoying the nice spring whether it may be in Freiburg or inFrankfurt a/M. We have now here about the same temperature as one hasat the end of April in Copenhagen and in a fortnight we shall havecherry‑blossoms in its full beauty. From now till the end of May, we
have one of the best seasons of the year.
With kindest remembrances and best wishes to yourfamily and yourself
rh
−

ya
ln
e

−

Y

es
c

N
．n
L
−
・

VA

CM

r

e
v

s
r

u
o
y

・
．30

Tokio, 22 Jan
Dear Professor Bohr,Thank you very much indeed for your kind letter of the 26th Dec.*
which I received about a week ago. 工 quiteunderstand that you had topostpone your journey for a year. We are, however, all looking forward
very much indeed to the visit of Mrs. Bohr and yourself to our country
in 1931, for which we shall make necessary preparations.
If you want
any information, please write to me. In case you further change yourplan, please let me know.
April and May is the best time for a visit to Japan in the spring.
The exact time of cherry‑blossoms, of course, varies from year to year
according to temperature. The Emperor gives a garden party to prominent* See Publication No.
20 Y. Nishina s Correspondence with N. Bohr and
Copenhageners, 1928‑1949， p.16.

9people in the spring and autumn. 工n the spring it takes place usuallyon about the 15th to 20th of April and this marks the end ofcherry blossoms in Tokyo, because the cherries in that garden are of thekind which blossoms late． 工 donot know whether you are interested to
四attend such a party; if you would like to do so,we shall be pleased toarrange it.
I thank you very much for a separate copy of your essays in the
University Aarsskript. I shall read them with a great interest as
well as with a happy remembrance.
With kindest regards to all your family and yourself.

目

．

晶

v
4a
︑
e
n
r
・
−
eh
c
s
n l

−

CM

LN

O

V＆

sy
工
u

Institute of Physical and Chemical
Research,Komagome, Hongo, Tokyo
23rd. August, 1930
Dear Professor Bohr,I thank you so much for your kind and interesting letter of the＊

4th. inst.
I am sorry to hear that you had to postpone your visit toour country until the spring of 1932.
We have been doing some
preparation for your visit, but that does not matter if you come here

*See Publication No.20 Y. Nishina s Correspondence with N.Bohr and
Copenhageners, 1928‑1949， p.17.

10
once at all; we are all so much looking forward to having Mrs. Bohr andyourself here in Japan in about one and half year s time. We haverecently been talking much about your visit and have always wished thatyou would stay here more than a month. From your letter, however, I now
see that you intend to spend just a month in Japan and 工 should like toknow whether this plan of yours is flexible or not. We should be very
pleased if you would stay longer in case you have time enough to do so.
That would enable us to learn something substantial about the principles
of atomic theory, the subject which we are most anxious to hear fromyou. We have of course nothing to offer you here in physics and you
will perhaps get tired, but you might find something which interests you
outside science.
工 ammuch interested in Jacobsen s experiments on the scattering ofhard radiation by various elements, as you wrote to me. I understandthe importance of the question, and if the effects reported by German
and English physicists are real, that wil1 give us another implement tosearch with inside the nucleus. I am therefore looking forward to
Jacobsen's results to see how large such effects are, althoughw.Kuhn's
results seem to point to the smallness of such effects.
工 am still being kept away by various external circumstances fromgetting into real physics and doing work of my own. 工 hope, however,that the conditions will soon improve and permit me to do somescientific work. At present 工 have to spend so much tim
e for lecturing,
colloquium, book‑writing, etc.
In this connexion, I miss theconversations which I always had with all people in your Institute.
Please send my best remembrances to all of them, especially to Klein,
Jacobsen and Miss Schultz.
Last April a boy was born to us, his name isgetting on quite all right.

β註F

Fand is官11

My wife joins me in sending our best regards to Mrs. Bohr, all yourfamily and yourself.
Yours Very Sincerely
Y. Nishina
P.
S. 工 shouldbe very much obliged to you if you would let me know
in case you make further changes in the plan of your journey in future.

Tokio, 24. 4. 1931
Dear Professor Bohr,I should like just to inform you, although you might know already・that Professor Nagaoka will leave here in a week s time for Copenhagen,where he is going to attend a radio meeting, I was told.
I hope thatyou will have an opportunity of talking with him about your visit toJapan.

He has just been appointed the first President of Osaka

University which will be opened on the 1st of May.
How are you and your family? and how is the life in the Insitute?
工 am very pleased to hear from Miss Sc
hultz that the ten year'sanniversary of the Institute was very pleasantly celebrated by thepresence of a great many of Copenhagener school.
Professor and Mrs. Hevesy visited Japan on their way home from
America and stayed about three weeks, of which they spent about ten daysin Tokio and its neighbourhood.
seemed to me too short.

I hope they enjoyed the stay which

12
工 am quite all right in health, but have very little time forscientific work． 工n a week s time I shall have to go to Kyoto to give・

lectures in the Physics Institute of the University. I shall stay there
three weeks, that will again prevent me fromdoingmy own work.
Professor Takamine will soon come to Europe from America, I wastold3 工 donot know if he will come to Copenhagen.

日eintends to stayat Utrecht for some time.
With best regards to your family and yourself
V6
A
︑
e

−

nh
−

ra
e
en

sl sN

−
・−

V4

E

ey
v

s
r
u
o

y

Tokio, 4‑7‑35
Dear Bohr
Dirac has been here already two
weeks and we are enjoying his stay very much.
And so is he.
We are all expecting you here in 1937 呈旦iare hopinq Heisenberq will come with you.
Honourable greetings from
Y. Nishina
P.A.
M. Dirac*underlinedwords: written by Dirac

13
．
．．
．
．
・
．
，
．
．．
．・
・
・ −− −−−−−−−−．
−、

14
The Institute of Physical andChemical Research.
Komagome, Hongo, Tokyo

Tokyo, May 28, 1937

Dear Bohr,I knew already at the time of your arrival in Yokohama that you had
to leave us in five weeks time, nevertheless I was awfully sorry when
the time came to see al1 of you off at Nagasaki. My sorrow was only
mitigated by the hope that we shall meet in not a distant future.
I thank you for your very kind post‑card, which you sent me from＊the steamer.

When I learned from it that you had a nice voyage, I felt

much relieved, because during that night we had a strong wind, therattling of which awoke me in bed of the hotel at Hakata. After
visiting my native place, I came back here in Tokyo a few days ago.
Everything reminds me of delightful, impressive and busy days I have hadwith you and your family. 工t is needless to say how gra七eful all of us
are for your visit to this country. Personally I have now much to thinkover what you told me during your stay, which has given me so muchencouragement, consolation, and strength in my life.
I am now waiting for your cable about your itinerary throughManchukuo, so that we can inform the authorities concerned to take careof your journey. Lieut.
ーGeneral Hatano of Japan Society for the
Promotion of Scientific Research and the President Nagayo of the Tokyo
Imperial University have already written to them about the matter but
the dates of your arrival given were not certain.
All your wood boxes have been safely sent to Yokohama and if things
have gone smoothly, they will be on board the Danish steamer which is*See Publication No.20 ・・Y. Nishina s Correspomdence with N. Bohr and
Copenhageners, 1928‑1949， p.60.

15

expected to leave Yokohama to‑day. I hope that everything will arrivein Copenhagen in good conditions.
Professor Tanabe, the philosopher in Kyoto, answered to me
regarding the criticism which appeared in the Kyoto news paper. In his
opinion it is unnecessary to answer to those articles seriously, because
they have no points of their own except antipathy and they wil1
therefore never be reasoned to agree.

工 quite agree with him and 工think we need not bother about it any more.
工 hopeyou have had a pleasan
七 and interesting journey in China andnothing has gone wrong with you all. 工 wish I could t工avel with you. I

really hope that you all will have a nice journey also through Machukuo
as well as Siberia and safely back to Copenhagen.
Please send my best remembrances to your family at home as well as
Hevesys, Miss Schultz and all those in your Institute, and also to
Kapitza and Kleins on the way.
With heartiest remembrances and best wishes to your wife, Hans, andyourself from my wife, children, andYours everY. Nishina
P.S. Please add the following persons to the list of those who didmuch for your decoration:
Professor H. Nagaoka,
工nstitute of Physical and Chemical Research,
Komagome, Hongo, Tokyo.
Lieutenant‑General S. Hatano,
Japan Society for the Promotion of Scientific
Research,
Monbusho, Toranomon, Kojimachi, Tokyo.

16

To‑day 工 have sent to your home the copies of Professor Nagaoka saddresses and the explanations for the doll presented to you by the
工mperial University of Osaka.

Universitetets Institut
for Teoretisk Fysik

Blegdamsvej 15, K戸
benhavn ￠July 3工d, 1937

Dear Dr. Nishina,
I herewith acknowledge the receipt of the Kr.112,07 which were therest of the expenditures in connection with the heavy water.* At thesame time 工 send the acknowledgement
K
v
a
l
'
lstofaktiese1skab.

from Norsk Hydro‑Elektrisk

It was a great pleasure through Prof. and Mrs. Bohr to hear thatyou are probably coming to Copenhagen again before too long. 工t shallbe very nice to see you again. Both Prof. and Mrs. Bohr and Hans aremost delighted over their stay in Japan and I am looking forward verymuch to see all the pictures they have taken.
With kindest regards,

ヲ
白

L

u

t
︐︑
V4U

︑ム﹄
e
c
rnb

e
cva
nt
t

O

s
− e
RU
S
E
U

Y

* See Publication No.17， G. Hervesy ‑ Y. Nishina, Correspondence
1928‑1949， p.18.

17
Lynghuset, Tibirkelunde pr.Tisvildeleje.
Universitetets 工nstitut
for Teoretisk Fysik

Blegdamsvej 15, K戸benhavn ￠August 3rd, 1937

Dear Nishina,
After a few weeks of very busy days since the return from ou工 long
journey, we are now quietly settled here in Tisvilde together with thechildren, whom we were happy to find all in good health. Eve工y day wespeak about our wonderful experiences in Japan and send you and all ourother faithful friends many grateful thoughts. We can never forget themarvellous beauty and enchantment of your country and it is often to us
as if we still were travelling with you and Takamine, Kimura, Sugiura,
Fukuda, Hori and Aoyama to Matsushima, Nikko, Hakone, Miyazima andUnzen; or that we were standing with you admi工ing the purity and beautyof the palaces in Kyoto or being deeply moved by the solemn dignity ofthe temples in Kamakura, Sendai and Nara.
The whole is a picture in our mind of beauties untold and happinessamong real friends and to the complete harmony of it all your untiring
care was of course the last clue. One of the most treasured pictures inour mind will always be the delightful hours in your home, where yourwife played so beautifully on her old instrument and where your smallboys were sitting each on his cushion with his little tray with thedelicious Japanese meal before him. We also often see our friends ‑ towhom we now always will reckon the kind and true Kuwaki ‑ at the quay ofNagasaki, when the serpentines were gradually breaking, but where we
felt that so many deeper cords were uniting us for ever.
日owkindly you wer
e still taking care of us, we felt all the timein China from your telegrams and from the arrangements made for us in
Manchoukuo, where all officials were most kind to us, and where we had a18

most pleasant and comfortable journey. Also in China we had a mostinteresting and delightful time. We saw most beautiful places like
Peiping and Hangchow full of marvellous historical monuments, and we met
everywhere with very great kindness from the Chinese scientists who aremaking great efforts in creating conditions for research work and werevery eager to enter into international scientific cooperation.
It has been a wonderful experience indeed to us to get to know theold countries so far away, and not least I shal1 be happy if my journey
will result in the strengthening of our old connection with thephysicists in Japan. As I promise, I shall take care that all our workand discussions which may be helpful in this respect wil1 be sent toyou.

In a few days Mrs. Schultz, who wishes to be very kindly

remembered to you, will send you a copy of the manuscript of a little
note which will soon appear in Science and the appearance of aJapanese edition of which in some semi‑popular journal, as we spoke of,may be a remembrance of my visit and lectures in Japan which I shallappreciate very much. Besides 工 gotsome days ago a very nice letterfrom Hori, who kindly proposes together with his brother to make aJapanese translation of my little bookAtomic Theory and the
Description of Nature
・As 工 am writing to him by the same post，工shall of course welcome such a translation with very great pleasure, but
as we had already touched upon this question，工 haveasked him to confer
with you about the whole matter.
Above all, however, the whole family and everyone in the Instituteare looking forward with the greatest pleasure to your visit here, andas soon as 工 have seen the directors of the Rockfeller Foundation, I
hope in September, and with them have discussed the various problems we
spoke about, I shall write to you in detail. When we come to Copenhagen
again in a few weeks' time I shall also send you and al1 our otherfriends the promised photographs and write the more official letters of
thanks to the Marquis Maeda and the presidents of the institutes and19universities. At that time I also hope that the boxes have well arrived
with the many precious gifts, which we look forward so much to have in
our home, and which the children are very eager to see.
With our kindest regards and very best wishes to yourself and yourwife and children as well as all other common friends in Japan.
Yours ever,Niels Bohr

The 工nstituteof Physical andChemical Research.

Tokyo,August 28, 1937

Komagome, Hongo, Tokyo
Dear Bohr,
工 thankyou very much indeed for your very nice and touching letter
which I received a few days ago together with the manuscript of yournote on Transmutations of Atomic Nuclei．
工n my opinion your visit to Japan will stand as a land‑mark in the

progressnotonly of physics and related sciences but also of

philosophy, genetics, and biology in this country.

I do not know how

many scientists here share this opinion with me but I am sure that atleast those who have come into close contact with you and haveunderstood your views will quite agree with me. In fact 工 have heard
the similar opinions expressed on some occasions.
In any case yourvisit has been and will remain a great encouragement and enlightenment
for my own scientific life. I often think of various things which you
told me and this gi
ves me life and courage to push on throughdifficulties and depressions.

20

Anyhow it is a great pleasure and satisfaction for me to see thatthe old connecting ties between you and our physicists were everstrengthened through your visit, especially through family contacts.
For us, who have worked in your 工nstitute, it was a great joy to have an
opportunity of having everyone s share in doing anything for you in
return to what you have done for us in Copenhagen.
I am very pleased to hear that you are back all in good health toyour home. Ever since you left here, we have been always tal
king about
the days of your stay here and sending you our thoughts. 工t was reallyan unforgetful remembrance for us all. When we meet, our conversation
recurs to the experiences we have had with you on various occasions.
In this connection it was very fortunate that you came here just ingood time. It would probably be impossible for you to travel China at
this time, because as you know bitter fightings are going on between
Japan and China. It is most unfortunate to have such a situation in the
Orient. 工 hope the peace will soon be restored but at present nobody
knows how long it will take. If it will not be finished before long, it
is possible that we cannot get sufficient fund for scientific researchand that would substantially retard our progress.
Regarding the Japanese edition of your
Sciencenote,
Transmutations of Atomic Nuclei， I shal1 take care of it to betranslated into Japanese and published in the October number of a semi‑
popular scientific journal Kwagaku which is a Japanese word forscience. I shall look after the translation.
As regards your note Kausalitat und Komplementaritat published in
the Erkenntnis， I have spoken with our publisher as well as several
persons who are interested in the matter.

We have come to theconclusion that if you agree, the translations of this note and Lightand Life" should be published together in a pamphlet form. They also

21

propose that the Japanese edition of Transmutations of Atomic Nuclei
and the translation of your Nature note， Neutron Capture and Nuclear
Cons七itution should also be published together in a pamphlet form.
These two pamphlets would make a very good remembrance of your visit tothis country. They want me to take care all of the translations.

Inthat case I shall consult with some workers in our 工nstitute andespecially in connection with the philosophical papers I shall consult
with Prof. Kuwaki and some othe工 people.
opinion about this proposal.

Please let me know yourWith respect to your book Atomic Theory and the Description of
Nature ，工 informed our publisher of your opinion which you told me atUnzen. They are of course very anxious to publish the translation anddesire that the theoretical workers in my laboratory would take care of
the translation under my supervision, as was done with Dirac's book.
工
was just going to ask your opinion about the matter, but now 工 see fromyour letter that Hori would like also to translate the book. I shallsoon get into communication with him and after settling the mattersatisfactorily, I shall let you know and ask your opinion.
工 thank you very much for your kind attention towards therealisation of my visit to Copenhagen through the aid of the Rockfeller

Foundation. I should of course be very happy, if I could come to
Copenhagen again and see your family and old friends in the 工nstitute.
After hearing from you the results of your conversation with thedirectors of Rockfeller Foundation, I shall make up my mind.
After you left Japan, we have been improving our cyclotron and we
get at present 3 to 4 microamperes at 2
.9 MV, which is limited by thesaturation of our magnet.

We are trying to increase the current but

have not succeeded yet. Our medical colleagues have been studying thebiological effects of neutrons and have obtained some interesting22

results. We sent a note to Nature， a copy of which 工 am sending you
by a separate post.
Another thing which may interest you is the study of cosmic ray
particles. As 工 told you on the occasion of discussions at the
University of Osaka, we have been studying by means of a large Wilson
cloud chamber the energy loss of cosmic ray particles in passing throughlead. In the course of the experiments, we found that there exist
particles which at higher energies radiate less than electrons and atlower energies ionise less than protons. This could most naturally be
explained in our opinion by assuming the existence of particles, themass of which is larger than that of the electron and smaller than thatof the proton, although this is not the unique solution. The sameconclusion had also been given by Neddermeyer and Anderson, by Street
and Stevenson, and by Crussard and Leprince‑Ringuet. We are at present
trying to obtain more exact value of the mass of the particle.
I amsending you a copy of our letter to the Editor of the Physical Review.
I should like to ask you to send me, if possible, two extra copiesof your photograph with your signature. We should like to send one ofthem to the family Yamada, in which Mrs. Bohr saw flower arrangements,
and the other to the doctor who examined your throat.
I hope al1 the boxes by this time have arrived in good conditions.
Have you received your colour films developed all right ? I hope they
have nicely come out.
With kindest regards and best wishes from us al1 to yourself, yourwife and all your family as well as all in the Institute.
Yours everY.Nishina

23
d

n
a

l
ay K

︒

cT

SE

−
−

−
c・
n−o

ya ︐

n
− e o
p
hsαJ
en

OM

fRO

可
ム
ea
︐

ゐ

Lmo
−
− e 9

K

tCe
u −− m

工

no

tha
s
cm

T

e
n
−

Tokyo, August 28, 1937

Dear Miss Schultz,
I thank you very much indeed for your kind letter of the 3rd. July
together with the receipt for heavy water, which I received some timeago.
I must apologize you for my negligence in correspondence. You
have been so kind and have written to me now and then to let me know thevarious happenings in the Institute. I have been immensely interested
in your letter but am sorry to have not answered to you. Hereafter I
shall take care not to fall into such a negligence.
工 thank you very much for the great trouble you have taken inconnection with heavy water.

We are very pleased to have it here anda工e using it everyday.
We have had a very nice time when Professor, Mrs. Bohr and Hans
were here. I suppose you have heard their experiences and by this time
you have also seen pictures they have taken here.
How are you now? We are all keeping well. 工t is a happy thought
for me to be able probably to come to Copenhagen some time and to see
you and old friends again in the 工nstitute.
With kindest remembrances and best wishes
Yours sincerely
Y. Nishina

24Tokyo,Oct.3, 1937
Dear Bohr,I must heartily apologize you that I have caused you and yourInstitute such an unpleasant trouble in connexion with the heavy water＊from Hydro‑Elektrisk Kvaelstofaktieselskab.
I regret very much to havecommitted such a serious mistake． 工 am very grateful to you that you
have settled the matter in such a graceful manner. We have had noenquiries either from Hydro‑Elektrisk" or from Japanese agent of thefirm and I presume that the people of the agent are now satisfied withthe correspondence they had with the Norwegian firm. 工 think thissolution is entirely due to your endeavour for which I sincerely thankyou. Every day we are using the heavy water for cyclotron and it
appears now to all of us to be much more precious than it used to be
before.
The translation of your Science note has just been published.
told the publisher to send you a copy of the journal.
copies of the note will also be later sent to you.

I

Some separate

I found that there is a difference between the note published in・・Science"and the manuscript you have sent to me. One sentence
The above considerations can therefore be applied in this si
mpleform only when the change in the temperature in going from thesecond to the third stage in Fig.3 is comparatively small.
at the end of the second paragraph on page 164 of

Science" is missing*See Publication No. 17 G. Hevesy ‑ Y. Nishina, Correspondence
1928‑1949， p.21.

25

in the corresponding paragraph on page 6 of the manuscript which you
sent to me. I should like to know whether or not it was deliberately
left out.
In my translation 工 added it； 工 can of course publish
correction if necessary.
I saw your lecture announcement in the programme of the Reunion
Internationale de Physique,Chemie & Biologie at Paris. Were there any
interesting discussions?
I hope you and all your family are in good health.
getting on all right.

We are all

With best wishes and kindest remembrances from us all to yourself,
Mrs. Bohr and your family,
Yours ever,Y. Nishina

Tokyo, June 15, 1940.
Dear Professor Bohr,
工 amvery sorry that I have not written to you for such a longtime,during which great changes have taken place all over the world. I
am very anxious to know whether you, your family and your Institute are
getting on all right. This has been a matter of greatest concern forme.
I have been ill for some time but I think I am all right now. 工nspite of the war between Japan and China, we have been able so far to26

pursue our scientific work without much hindrances.

The operation of

our 200 ton cyclotron is not yet in right conditions, but I hope thatwill soon be brought in order.
工 should like very much to hear from you indeed and I send you andyour family our best wishes for the time being.

Yours everY, Nishina

Post Card
Kamakura, 17/V工
工， 1941
Dear Hevesy,
Our old friend Rosseland has suddenly appeared here with hisfamily,we are enjoying their stay immensely, which is really too short.
I have been trying to get in touch with the authority in Denmark inconnexion with your transit visa, but the war between Germany and Russia
made everything in vain. With best wishes to your f品mily and yourself.
Y. Nishina

I hope you & Mrs. Hevesy are very wel1.

I just returned from

America after 1 1/2 year s stay in Pasadena & Berkeley. It was reallyan unexpected pleasure to have Rosselands visiting Tokyo.

27

I certainly wish you & Mrs. Hevesy should visit us again.
Yours, T. Takamine

We have had the happiest time in Japan, and expect to arrive in
California by 1/VIII.

This is a delightful occasion to send you andMrs. Hevesy our heartiest greetings.
Yours everS. Rosseland

May I join in sending you greetings and good wishes.
Ragna Rosseland

I am longing to see you.
Suma Takamine

2 Poelgeesterweg, Oegstgeest (Leiden)・

10 July 49

Dear Nishina,
Just a word to tell you how glad I was to see your name, as vice‑president for natural sciences, on the letter announcing the formationof the Science Council of Japan. 工t was sent to me, since I am atpresent the President of the 工nternational Union of Pure & Applied
Physics. Secretary is the Professor Pierre Fleury， 工 nstitut d Optique,
3 Boulevard Pasteur, Paris XV; his energy has made it possible, that theUnion is very much alive, in these years. We get grants from UNESCO,28

for paying the voyages of foreign physicists, who attend the many
Congresses which we have held and are holding in these years in Europe.
In Basel, 5‑9 Sept．49, there will be an international conference on
nuclear physics, the week after a similar one on cosmic rays in Como
(Italy). Although Germany is not yet an official member, some Germans
have been invivted too.

Unfortunately, our means are small, otherwise

we would have been glad to invite a Japanese physicist, in particular
you, too. The Swiss Physical Society, would certainly have been glad towelcome you in Basel． 工 suppose the Japanese have hardly the money now,
to send delegates or a delegate to Europe ？ 工 f there were apossibility, it would be wonderful to see you again, and I would takethe question up with Prof. P. Hube工，Basel.

who organises the Congress in日oware you and your family ?

And can you experiment again, in away, after all the disasters of the war ? It would be good to havenews from you. In an indirect way, we have heard a good deal about theinterim work on physics in Japan, mainly through your journal. Mr.
Araki sent me several interesting reprints on things I have been working
too in old times.
How are our old friend Takamine & Mrs. Takamine, and Mr. Sugiura,
who also were at Copenhagen?
Mrs. Kramers and myself and our 4 children are all right, although
I myself have been severely il1 in 47, and have not yet got back theold energy.
With our most cordial regards

s
r

rE

V4e

lm

ek

ea

S

FV
n
−
iA

SH

r

u
o
y

29

Professor H. A. Kramers

August 27, 1949

2 Poelgeesterweg, Oegstgest,
HollandDear Kramers:
Thank you for your nice letter which 工 was so pleased to read after
such a long interval of isolation.
工 should like to tell you that I am coming to Copenhagen to attend

the general meeting of the 工nternational Council of Scientific Unions tobe held on September 14 ‑ 16. 工 wonder if we can meet there, it would
be very fine.
Dr. Stratton wrote to GHQ in Tokyo and asked whether Japan can senda delegate to the meeting, and if it is agreed, the possibility forexternal financial aid will be explored. Thereupon GHQ replied in theaffirmative.

But lately Stratton sent a telegram to GHQ informing thatthe financial means could not be obtained. Meanwhile GHQ decided tobear the expense and I shall leave here on September 8 and arrive in
Copenhagen on September 13 via London by B.O.A.C plane.
I am sorry that I can attend nei七her Basel nor Como Conference. For
such an attendance a formal inquiry to GHQ is necessary and now it is
too late.
工 shal1 leave Copenhagen on September 22 or earlier if I go to

Paris for UNESCO meeting and arrive back in Tokyo on September 27.
Please send my best regards to Mrs. Kramers and your family.
With best wishes,
Dr. Yoshio Nishina

30

担巴珪主主
Letters from N. Bohr to H.C. Kelly, D.W. Bronk and E.O. Lawrence
after Y. Nishina s visit to Copenhagen, and their replies to
N. Bohr (See Publication No.20 Y. Nishina's Correspondence with
N. Bohr and Copenhageners, 1928‑1949， pp.65‑70.)

September 22, 1949
Dear Dr. Kelly,
I am writing to tell how happy we have been here in Copenhagen for
the visit of Dr. Nishina who, as you know, worked for years in thisInstitute, where he won the warmest friendship of all of us. .
we weredeeply impressed by his truly human attitude which together with hishigh scientific qualifications and untiring zeal should make his
activity most valuable in the great and difficult task of restoring
conditions in his country. His stay here was an extreme pleasure to us
al1, and we hope also an encouragement to himself, and we are deeply
grateful to you for facilitating his journey to Denmark.
I understandthat also a journey to U.S.A. of a group of distinguished scientists
including Nishina has been planned and I am sure that such a visit will
have the greatest effect in promoting cooperation in the proper spirit.
FromAmerican delegates to the meeting of the International Council of
Scientific Unions, which Nishina attended here, I also learned that thevisit will be most heartily welcomed in scientific circles in U.S.A.
With the same post I am writing to the Secretary of the National Academyof Sciences in Washington, Dr. Bronk, who is a personal friend of mine,31
to express my pleasure in hearing about this plan and my hope that it
will soon be realized.
Yours sincerely,
Niels BohrDr. Harry C. Kelly,
ESS/ST, GHQ, SCAP,
APO 500,
Tokyo, Japan

September 22, 1949
Dear Dr. Bronk,
I am writing to tell that in these days we have had the great
pleasure of a visit of Dr. Nishina from Japan who, as you may know,
worked for several years in this Institute and won the warmest
friendship of us all. We were deeply impressed by his truly humanattitude and it was most interesting to learn about the conditions forscientific work in Japan and again to establish such contact of which we
all in the earlier days p工ofited so largely. Dr. Nishina came to attend
a meeting of the International Council of Scientific Unions and hisjourney was arranged by the kind assistance of Dr. H.C. Kelly, who isscientific advisor to the American occupation authorities, and by Dr.
Fraser, who is liaison officer between UNESCO and the 工nternational
Council. From Nishina 工 heardthat there is a possibility that he and afew other distinguished Japanese scientists may come to U.S.A. in a near
future on the initiative of the National Academy of Sciences and 工 amsure that the contemplated visit will not only be a great andencouraging experience to the Japanese scientists, but will also be agreat help to promoting co‑operation in the proper spirit.

As 工

32
understood, however, it might be of help for the arrangement of permits
etc. if at early convenience a formal invitation from the Academy wassent to the Japanese scientists concerned, and 工 thought therefore that
I ought to mention this to you.
工 often thin
k of our talks in Philadelphia and Washington, and mywife and 工 remember with great pleasure our visit to your home in theforest. We both send you and your family our kindest regards.
E・＆

︐
V4

S

︑
e
r
eE

Ch
no
B

V4

S
−

re

e
ム
︑

S

VN
−

r

u
o
y

Dr. D.W. Bronk,
Foreign Secretary,
National Academy of Sciences,
2101 Constitution Avenue,
Washington 25, D.C.

September 22, 1949
Dear Lawrence,
工t was a very great pleasure to have a short visit of McMillan who

told us about the latest progress of the wonderful research in Berkeley.
At the same time as McMillan was here we had a visit of Nishina, whom wewere so happy to see again after the long years of separation.

Nishinatold us about a contemplated visit to U.S.A. of a group of distinguishedscientists including himself.

On the advice of McMillan who knew how

much you would welcome to see Nishina in Berkeley I enclose for yourinformation a copy of a letter I am sending Bronk in case you yourself

33should want to communicate with him about the matter.
With the kindest regards and best wishes from home to home,Yours,
Niels Bohr
Professor Ernest 0. Lawrence,
Radiation Laboratory,
University of California,
Berkeley, Ca.

October 3, 1949Professor Niels Bohr
Universitetets Institut for Teoretisk Fysik
Blegdamsvej 15
Copenhagen, Denmark
Dear Professor Bohr,I was, needless to say, very glad to get your lette工 and to knowthat plans are afoot to bring Nishina to the United States. McMillan
discussed the matter with me and 工 telephoned Bronk to inquire what isbeing done and whether there was anything I could do. Bronk indicatedthat he was actively working on the arrangements and so I gather there
is an excellent chance that we will have the pleasure of seeing Nishina
over here sometime this winter. Al1 of us here would be pleased beyond
words if Nishina could spend some time with us in Berkeley.
McMillan told me about his visit with you and I was especially glad

34

to hear that everything is going very well indeed with you and yours in
Copenhagen.
Molly and 工 sendyou and Mrs. Bohr our warmest greetings.
Sincerely,
Ernest 0. Lawrence
EOL:E工19 October 1949
Professor Niels Bohr
Universitetes Institut for Teoretisk Fysik
Blegdamsvej 15
Copenhagen, DenmarkMy dear Professor Bohr:Thank you so much for writing me concerning Dr. Nishina andpossible arrangements for his visit to the United States.
工 have been much interested in the proposed mission of Professor

Nishina and several of his colleagues. The National Academy of Sciences
will be glad to sponsor their visit, and the only matter which remains
is that of securing the financial means for their journey and visit. I
have at last received definite assurance that such funds could be madeavailable through the organization of which Dr. H. C. Kelly is a member.
Accordingly, I have again telegraphed to Dr. Kelly and written to him
asking him to explore the possibilities of securing these funds and tolet me know promptly, so that we can advise Professor Nishina and thus
avoid the necessity for his returning to Japan before coming to the35States. Perhaps you could arrange to keep Nishina with you a little
longer until I secure definite information. Just as soon as 工 have suchinformation I will let you know.
工t seems impossible that three years have go
ne since we had thevery pleasant visit from you and your wife and our other guests of the
National Academy of Sciences. 工 do hope that you will both be coming
over again soon, for I regret that I did not have more than a glimpse of
you when you were here a year ago.
With every good wish to you both from Mrs. Bronk and me， 工 am
Yours sincerely,
Detlev W. Bronk
Foreign Secretary
DWG rgGeneral Headquarters
Supreme Commander for the Allied Powers
Economic and Scientific Section
Scientific and Technical Division
APO 500
Dr. Niels Bohr

19 October 1949

Universitetets Institut for Teoretisk Fysik
Blegdamsvej 15
Copenhagen, Denmark
Dear Dr. Bohr:Your kind letter regarding the visit of Dr. Nishina is deeply

36

appreciated. We completely share in your view of Dr.Nishina, for he isdoing a superb job both for the economic recovery of Japan and thedevelopment of international understanding.
Withthe greatest respect for your leadership in promoting

cooperation and understanding, I am
Sincerely yours,
Harry C. Kelly

Corriqenda
Publication No.17. G. Hevesy ‑ Y. Nishina, Correspondence 1928 ‑1949
p.24,
J
.
. 6: Cyklotron ‑ Cyclotronp.27(cover),.l.11: (Post Card） 宇 （ Postscript)

Publication No. 20

Y. Nishina s Correspondence with N. Bohr and

Copenhageners 1928‑1949
p.3, l.
l7: F 1
1edparken ‑+‑ Faalledparken
p.19, J,
.l7 from the bottom: Nord Jylland 干−

Nord Sj
官
民 landp.22, J,. 8: I so often written
I have so often written
p.29, t.11: waiting to see .
.
.
. waiting so long to seeSupplement to the Publications No.17, 20, 21
Name

Place

Date

From 0. Klein

Copenhagen

From 0. Klein

Copenhagen

From・o. Klein

Copenhagen

To

G. Hevesy

Tokyo

To

N. BohrTo

N. Bohr。 N. Bohr

T

1928

1

2/X工
工

1928

2

23／
工

1929

4

1/IV

1929

6

Tokyo

22／
工

1930

8

Tokyo

23/V工工工 1930

9

24/IV ‑1931

11

4/VII 1935

12

Tokyo

TO

N. BohrTokyo

To

N. Bohr

Tokyo

28/V

1937

14

From B. Schultz

Copenhagen

3/V工
工

1937

16

From N. Bohr

Tisvilde

3/V工工工 1937

17

To

N. BohrTokyo

28/VIII 1937

19

To

B. SchultzTokyo

28/VIII 1937

23

To

N. Bohr

Tokyo

3/X

1937

24

To

N. Bohr

Tokyo

15/V工

1940

25

To

G. Hevesy

Kamakura (Post Card) 17/V工
工

1941

26

From H.
A. Kramers

Leiden

10/V工
工

1949

27

To

Leiden27/VIII 1949

29

H.A. Kramers(Post Card)

27/X

主主豆全

AppendixFrom N. Bohr

30
Copenhagen

To H.
C. Kelly

22／
工X

1949

30

To D.W. Bronk

22／
工X

1949

31

To E.O. Lawrence

22／
工X

1949

32

From E.
O. Lawrence Berkeley

3/X

1
‑
949

33

From D.W. Bronk

Washington

19/X

1949

34

From H.
C. Kelly

Tokyo

19/X

1949

35

To N. Bohr