bei FrauNolte
Schillerstr. 49
Gぷttingen,Germany
25th Mar. 1923
To
ProfessorN. Bohr
TheoreticalPhysicsDept.
University of Copenhagen
Denmark
Dear Sir
You may remember that I was working in the Cavendish Laboratory when you
came to Cambridge about a year ago. At that time I was counting B‑rays
excited byy‑rays bymeans of Geiger s counter, and had the honour of speaking
to you in the laboratory.
I left Cambridge last September and came here for the purpose of learning
the German language.
As I spoke to you in Cambridge, I have the great desire of studying in
Copenhagen under your guidance, and I should be gratefully obliged to you if
you could acceptme.
As my Institute in Tokio does not allowme to stay in Europe longer than
twomore terms, I do not knowwhether it is wise to set up newwork. My chiefwish is to study your theory of spectra and atomic constitution in details.
But if any onewants assistance in the experiment or the calculation, I should
do itwith pleasure.
I should esteem it a favour if youwould giveme the early information inthematter.
I beg to remainYours faithfully
Y.Nishina
p.s.
I belong to the Institute of Physical and Chemical Research in Tokio, towhichDr.Takamine also does as you know.

2
bei Frau Jaeger
Schloss‑str. 1
7Charlottenburg, Berlin
4th April, 1
92
3To
Professor N. BohrUniversitetets Institut
forTeoretiskFysik
Copenhagen
Dear Sir,I thank you very much indeed for your kind letterwhich was forwarded tome yesterday.
It is my great pleasure to be able to study in your Institute, and I
should like to express my sincere gratitude to you for your kind acceptance ofme.
I have some business here inBerlin, which I have to finish before I cometo Copenhagen. As soonas I finish it, I should like to start at once.
Thankyouvery much for yourkindness re the passport v
i
s
u
r
n
, inobtaining
which I do not think I shall have any trouble. One thing about which I am
anxious is the lodging in Copenhagen. I shoud like to find a family in which
German is spoken.
As soon as I decidemy departure, I willwrite to you.
Once againassuringyouof my gratitude,Yours faithfully
Y. Nishina

3
K同benhavn1
3. 1
0. 24.
DearProf.Hevesy,
Thank you very much indeed for your pretty card of your native town. I
amvery happy to read inyour lines that you are enjoyingyourholidays.
We have nothing startling here. But I made some experiment on the X‑raychemical analysis with the help of Schj世nning. The result may interest you,although it is rather disappointing.
I made Sb, Sn analysis as Coster did. I made different compounds ofthese elements and took one of each at randomand madeX‑ray analysis. In allcases Sn gives lines 6 times as strong as Sb. Next I mixed CaSOλindifferent
percentage to the mixture of Sn and Sb. At small % of CaSO,~ Sn is still
stronger, but this difference decreases with the % of CaS
1),, until theintensities are equal for Sn and Sb. Coster s experiment was in王his stage of
mixture, and it gave the satisfactory result. From this result,we know that
we should be very careful in the X‑ray analysis. For instance, in the case of
Hf,Cp analysis we find the ratio of any two lines experimentally for certain
amount of ZrO. This ratio may not be applicable for different percentage of
ZrO. This is very awkward result in principle. Of course, practically it may
not be so serious in the case of Hf, Cp analysis, because Hf, Zr, Cp havenearly t
he same chemical and physical properties, but we have to test thispoint
. I am expecting Jantzen now and if he comes I shall tell him to makecertain this point, before he makes any analysis. Otherwise it may givewrong
result. Of course all the samples which he is going to analyse, may havenearly the same% of Hf, thenhe has noneed of doing this.
There is one thing I should like to ask you. This may disturb yourpeaceful holidays, if so please excuse me. If you have an opportunity ofseeing Auer during your holidays or you have any good chance at any time,
would youmind askinghimwhether he could give one complete set of rare‑earth
group to Japan or rather to me. For if I go back to Japan, I cannot do any

4work on rare‑earth. This is not urgent. When you have any good opportunity
please ask it forme.
I hope youwill have the real rest during your holidays.
Yours,
Y. Nishina

K世benhavn, 24.
10.
24
My dear ProfessorHevesy,
Thank youverymuch indeed for your letter of the 18th inst. I am reallyvery glad that you are recovering in your health. Some people think that a
man s mental faculty is quite independent of his bodily conditions. Of
course, genius is geni
us from his birth. But in my opinion the capacity andability ofmental power of a certainman ‑ be it a genius or anordinaryman,are function of his materially bodily health. Therefore it is most essential
for you to take advantage of this opportunity in recovering fully from yourpresent condition of health．ー−−− I don tknowhow your present condition ofhealth stands, because you look cheerful always, but I take, your health is
not in full vigour as you wrote to me. Todo this, it may cost time. This is
my opinion and I think you know already this very well already and are doing
your best in improvingyour health.
Thank you very much for your kindness that you will ask Baron Auer insome future opportunity to spare me a complete collection of rare‑earth. I
should bevery much obliged to you and Baron Auer if I could get it.
I thank you again for your taking trouble in writing to Honigschmidt. We
will wait his answer. Wehave got the casting of the spectrograph alreadyand
Olsen is waiting just for the sketch. He cannot work unless we get thesketch.
Jantzen came back here last week and has set up the apparatus with atransformer and a rectifier. He will first test the effect of Zr02 (100% 80%)『

5
onHf/Cp ratio.
As regards the publication on chemical analysis with X‑ray, I am not in
position todo it now. Itwould be criticismofDr.Coster s work. Therefore
unless he publishes something I shall not publish anything. And even afterhe
will have published about the applicability of the method, I do not knowwhether I publish the material I have got, in my name or not. You know myknowledge onX‑ray spectrographwas given byDr・Coster.
But the results we have got must be published as soon as possible,
otherwise someone may find the same thing and criticize Dr. Coster. The
question is how to publish it. Perhaps you and Dr. Coster will conununicate
about the matter and decidewhat to do. Meantime I can speakProf. Bohr about
thematter.
On the other hand the matter is not cleared up yet. To find the reason
and to find out in what extent this method can be applicable for different
elements, are a great work. This will certainly take long time. The results
I have got, suggest the reason of the phenomena although it is very vague. If
Kimura comes here and if he wants to work in this line I shall continue thework, but he will not perhaps come this year, because he has not written
anythingyet tome.
Professor Bohrhas received 0rsted s medal lately. He is atTisvilde now
but will be back tomorrow.
I shall not trouble you anymore. Hoping you enjoy yourholidays.
With the kindest regards
truly yours
Y. Nishina

6

K
i
,
b
e
n
ha
vn 18.11.24
Dear Prof. Hevesy,
How are you ?
country.

I hope you are enjoying your holidays in your native

Thank you very much for your t・aking trouble in writing to Prof.
Hδnigschmidt for the sketch of the spectrograph. We received the sketch about
two or threeweeks ago and Olsen is nowworking according to it verywell.
Dr. Coster wrote to me about three weeks ago asking for some data ofabsorption spectra. In my answer I added some remark on the X‑ray
quantitative analysis, giving some information about the results I got. I
told him that you informed me of his intension of writing a note about thequestion, and I added that such a publication would be very desirable because
somebody who would begin a little work on this line, would easily be able tofind out the difficulty and would pofot out it beforeDr. Coster says anything
about it.
Dr.Coster s answer which I enclose herewith was that he prefers to wait
somebody s definite proposal. What do you think of the matter, ・because I
really do not know how to do with it. Please let me know your opinion aboutit.
Jantzen is working very well and I think he has written to you about his
results, sol shall not go into this question. Only one thing I have to tell
you is that the change of% of Zro2 has no appreciable effect on the relative
intensity of Cp and Hf. Of course if you change in very wide range, there
would be some effect, but within the limit which he is working with mineral
analysis, we can neglect the effect of ZrO今 content. This is what I haveexpected c1nd is very favorable for our analysls.
I am working on Hf Lγ again at present. Prof. Pirani wrote to me theother day in answer tomy retterwhich youwrote forme, as follows:
In Beantwortung Ihres Schreibens v
orn 22.Aug• . . . . . teilenwir Ihnen rnit,dass wir keine Osmium Vorrate mehr besitzen. Wir haben seinerzeit alles
verfiigbare Os‑material andie FirmaHeraeus G.m.b.H. inHanau gegeben.

7

Ihre Mitteilung, dass das ubersandte Molybdan Wolfram enthalten hat, hat
uns verwundert und es ware uns interessant zu erfahren, welche MengenWolfram
Sie gefunden haben.
Wir !assen Ihnen beifolgend nochmals einige Meter 0.2 m.
m. dicken reinen
Mo‑Draht zugeben inderHoffnung, dass er fur Ihre Zwecke genugenwird.
I wrote tohim thanking for his kindness in sendingmore pureMo‑wire andadding that I could not decide howmuchW the fomrerMo‑wire contained.
I tested the new wire which Prof. Pirani sent to us and found that it
contains a few percent of W and is of no use for me. Now I am using
Wehnelt‑cathode, which seems tome to solve t
he problem.
Hoping once again that you enjoy yourholidays
Yours
Y.Nishinap.
s. Mrs. Obrutscheva asked me to send you her kindest regards.

K
!
i
l
b
e
n
h
a
v
n, 21.
1
1.24
Dear Prof. Hevesy,
I just send you a line in order to call your attention to the paper ofA.
A. Russel of Oxford in the last number of the Nature. (p. 717, Nov. 15,1924). What do you think of it? Does it favour our view on the existence ofheigher atomic number (94 or 96)?
I have not tested the Ur‑mineral yet, because I h尋ve to finish my paper
first and now the X‑ray tube cannot stand so high tension, as I have used it
for long time.
When I finish my present work, I sh品11 change the X‑ray tube and try theminerals. But I am afraid it will take fairly long time befor I finish my8present work.
once.

If, however, you think it is very urgent, I shall try it atYours truly
Y.Nishina

K世benhavn, 29.11.24
Dear Prof.Hevesy,
Thank you very much indeed for your letter of the 22nd inst. which I
received thismorning.
As regards the way of publication on the X‑ray analysis, I quite agreewith you. I spoke with Prof. Bohr this morning and he thinks too that yoursuggestion will be the only way to do. I am just going to write to Dr.
Coster, sendinga copy of your letter and askingwhether he agrees or not. If
he agrees I shall begin to write a paper and publish it as soon as possible.
Of course, before I send it to the Chemical News" I don t know whether itwill be before or afteryou come back to Copenhagen.
Wehnelt cathodeworks verywell and the all difficulties arising from theW‑cathode are overcome now. I have sent my paper to the "Phil. Mag.
， but
there are a lot of correction to be done in that table and I am extremely
busy now. The paper mentioned above cannot be begun before I finish thepresent work, whichwill perhaps take onemoreweek.
With regard to Russel s paper, there is nothing direct connection with
our problem. He says that if we accept the atomic weight of R
a
S
l and
calculate that f Ur acc rding to the radioactive transformation, thece.
lculated value comes out O.1
4 smaller than the experimental values, and heemphasizes the necessity of redetermination of atomic weights of theseelements. If now we take the experimental values of the atomic weight as
true, then we can explain the discrepancy mentioned above by the presence of
higher atomic number elements (94 or 96). This was the point which I wanted
to tell you. But there are so many possi.
blities of explaining the above

。

。

9
discrepancy and it does not necessarily come to the conclusionwhich favours
the presenceof 94 or 96.
There is nothing startling for me. I work hard in the cellar as usual.
The life is only hard and therefore it is interesting.
I hope you are enjoying your holidays.
Yours truly
Y. Nishina
K品benhavn, 6.
2.
25
My dear Prof. Coster,
I enclose herewith the tables of energy levels. Of course, there aresome uncertain points, but the values in the tables are perhaps the best ones
we can get at present. But I am sure some values ought to be corrected in the
future.
About the corrections in our paper on the chemical analysis which you
suggested me, I spoke with Prof. Bohr, as regards the first suggestion about
the correction due to the difference in critical tensions of Ta and Hf wequite agreed with you. Especially Prof. Bohr told me that paper seems to be
too long for chemists and I tried to make it shorter, omitting the part you
suggested. But afterwards I came to the idea that this paper ought to be
written in as much detail as possible, because this paper deals with the realpractice of the method. Therefore anyone ‑ chemists or physists who try to
use this method oug
ht to know the wholematter in every detail which we dealt
with in our paper. Therefore we had better write the method in details to
showchemists how it ought to be in practice.
I told this Prof.Bohr who agreedwithme to do so・ From this standpoint
I also rewrote some part of the paper, and did not omit that part which deals
with th色 corrections due to the diff. in critical tension. The second
correction you proposed, that is the reason of the phenomena, I thought I omit
it according to your suggestion. But meantime Prof. Glocker in Stuttgart
wrote to Prof. Hevesy that he developed the quantitative chemical analysis by10
means of absorption coeff. in the nei
ghbourhood of absorption edge. He
pointed out that the method of emission spectra may be unreliable due to thedifference int
he temp. of evap. of different components in the preparation.
This may be the reasonwhyhis result and Hevesy s result do not agree.
Under these circumstances I thought we had better give t
he reason which
was written in our paper. So I spoke to prof. Bohr and Prof. Hevesy thispoint,who agreed to let )
:
"
e
m
a
i
nt
hat part in our paper.
That paper is under press and I amexpecting the proof.
y.N.

K世benhavn,1
7. 7. 25
DearProf.Hevesy,
τhank you very much for your letter of the 1
4th inst. as well as apost‑card which I received some time ago. I amvery glad tohear t
hat you andMrs.Hevesy are bothverywell and enjoying your holidays.
I am quite all right and working as usual. With regards t
he analysis ofEu, several circumstances have prevented us from determining the accuratecontent of Sm and Gd. First of all,t
he cleaningof rooms took a few days andt
hen the work has been interrupted by the work of new building. The water,
gas and electrical connexions are to be made to t
he newbuilding and therefore
all these cannot be used for about a week and so on. So we cannot work atpresent. Another trouble wa$ in the method itself. We have made a wrong
estimation of Gd and Sm, t
hey are not so much as I thought at first, and themethod we used was not appropriate for these contents. But we could get thevery rough estimation from what we have done, chat ‑is Gd 8‑9%, Sm about 2%.
Accuracy is very bad, perhaps 1% may be in both direction of the figures
given. I wonder if such a rough idea is of any service to you, but I informyou as far as we have done. We can begin work again next Wednesday, t
hen wehope to determine it more accurately and as soon as we get the results, I
shallwrite to you the figures as well as t
hemethod used.

1
1

I wonder if Stefan Meyer has tested the effect of other elements on therelative determination of Gd. We have tried and perhaps in thenei
ghbourhoodof these elements, there seems to be not effect of one element on t
he relative
intensity of other elements. But these points are not yet decided and weshall try it once morewhen we begin thework.
As regards the results of Goldschmidt, I suppose he used the differentsam
ple from the one you used. You know wehave two bottles. The one you used
for t
he atomic volume determination contains much more Gd than the othersample. I wonder if you sent t
he other sample to Goldschmidt. Theneverything can be explained. I cannot say how much the other sample contain
Gd. But it is decidedly less. I don t knowwhich sample St. Meyerhas used.
As soon as we finish t
his determination, we shall determine the
Hf‑content of Glocker s sample and Auer‑Gesellschaft s one. Then I shall test
Ur mineral for 94 and 96. Prof. Bohr told me that it is high time to test it
because 43 and 75 are discovered.
We are all well. Dr. Takamine went to Utrecht about a fortnight ago andhe is comi
ng b
a
c
!
< here to‑day or to morrow. Mrs.Takamine and Dr. Kim
ura arequite all right and asked me to send you and Mrs. Hevesy kind regards.
Werner,Ray and Kuhn are allworking verywell.
I hope you keepverywell and make a good progress inwriting the book.
時

With the kindest regards to Mrs.Hevesy andYourself,
Yours Very Sincerely
Y.Nishina
p.s.Thank you verymuch for your invitation to Hungary but I don t knowwhether I canhaveholidays. Wemust finish the intensit
y businessbeforeRay leaves here; if he leaves here this year at all,hemust
leave in September. Prof.Nagaoka is coming in August. I saw inNaturwissenschaften" an interesting paper of Prof.Miethe on
Hg
ーがAu‑business. His work is nowquite on the same line as Prof.
Nagaoka s and he has got the same results. So if one is right I thinkboth are right. I cannot saywhether it is right, but I had theimpression that the possibility is not excluded.

1
2
K,Sbenhavn, 1
2
.8.2
5
.
Dear Prof. Hevesy,
Thank you very much for your kind letter of the 22nd ult., to which I
ought to have written an answer a long time ago, but I was unable to do soowing to the delay of the Eu‑analysis, which has just been finished. I
expected it finished at the end of last month, but the building business tookmuch longer time thanwe thought. The result of Eu‑analysis is as follows:
Eu O
89.9%
23
Gd O
5.6±0.5%
23
SmO
4
.
5
:
!
:
0
.
4%
23
the sample being converted into oxides. The figures will be slightly
different, if you calculate it as sulphates.
As you see from the above, the Gd‑content is surprisingly small, muchsmaller than I thought at first. This wrong estimation was due partly to thewrong exposure of the plate, Gd being much stronger exposed than Eu, andpartly to the saturation effect of the photographic plate‑‑i.e. blackness is
not proportional to the intensity of the lines. But one plate which I had
takenjust before you left Copenhagen and ofwhich I telephoned to you, rather
confirms the above result.
One circumstance which made our analysis a little uncertain was that
Kimura by mistake mixed Gd to Eu‑preparation. This is the reason why I
reported 8% Gd and 2% Sm in my last letter. But now the above result agrees
with some plates which we obtained before Kimura mixed Gd, so I think theabove result is quite right. But if you want it to be absolutely certain, I
should advise you to repeat the determination of the atomic vol. with theother sample (which you sent to Prof. Goldschmidt), which we have here andthen we shall determine the Gd and Sm content in that sample, because we haveno more of the old sample.
The above result agrees well with that of St. Meyer antl Lhi8 i8 al8u the
support of the correctness of our results, because it is quite probable that
Auer sent the same sample to St. Meyer and you. Anyhow I wonder if the above
results disturb the curve of your paper, I hopenot. I amvery sorry that our13
result came too late and it came out differently from the previous figure I
gave you, butwe could not help it, althoughwe workedvery hard.
We have used two methods, one of which was not very suitable to our
purpose and the final result was obtained by the method of comparison of Gd
L.
t3
1 with Dy 1ti̲1 and Smwith Nd Lα1・ We tested the effect of Eu on theabove comparison ratios and found that there is no effect.

1si

Now that Kimurahas finished this analysis,hehas begun the Hf‑analysis,
which I hope he will soon finish. As soon as he finishes he will write theresults to you. After that he will proceed to the absorption problem. Thisbusiness will give very interesting results but I am afraid it will takerather long time.
Thankyou somuch for drawingmy attention to your Kajak . I have quite
forgotten it. But even if I did not forget, I could have not enjoyed it thissummer because I have had no time. I hope, however, I shall enjoy it later
thismonth.
Thank you so much also for your very, very kind invitation to yourcountry which I should ljke to see. But I am afraid I cannot come this year.
I have quite a lot and do now, especially with the intensity business. So I
have to putmy hope to the future.
Last month (about the 20th) we had Prof. Katayama here. He stayed 3days. He was sorry that he could not see you and sent you the kindest
regards.
Prof. Nagaoka will come here some time next week, I dor.
't know what hewill say about my stay here. Anyhow I have quite a lot to talkwith him.
As regards the explanation why Eu is not non‑magnetic, we can put forth ahypothesis, but we cannot say anything beforewe test it.
How are you getting on with your Handbuch" business, I hope you havemade a good progress and you are keepingverywell andMrs.Hevesy too.
Everyone here is all right and asked me to send Mrs. Hevesy and yourself

1
4

the kindest regards. Takamine, Werner, Ray, Kimura and myself are allwho arein the Institute now. Prof. Bohr and his familywill soon come backhere, andProf. Kramers are going to Oslo for the Physicsmeeting.
Please remember me toMrs. Hevesywith the kindest regards
YoursverySincerely
Y. Nishina
p.s. P]easewrite to Auer‑Gesellschaft inBerlin to be sokind that they
send us Mo‑plates of the following dimensions:

K世benhavn, 1
7
.9
. 25.
DearProf. Hevesy,
Verymany thanks for your letter of the 19th Aug. and Mo‑plates which you
sent toDr.Kimura.
As regards the Mo‑plates I shall write to Schwarzkopf in Berlin, as you
suggested. I am sure he has got it, because I remember he once supplied
W‑plates to me.
I am very sorry to inform you that Dr. Kimura has been suffering fromlung‑tuberculosis since the beginning of this month and is now in the Rigs‑
hospital. The disease is quite at the beginning and I hope he will be cured,
but I suppose it will take rather long time. Hewill go before long to Veile
Sanatorium. The doctor says that it is not necessary to stay in the hospital
here, so better go to Veile where the arrangement is good and the air is
fresh. He had just begun the Hf‑analysis when he fell ill and he is very
anxious to finish that analysis, but of course it is out of question to work
now. I am really sorry for him, because he has parents, wife and a baby athome. He asked me to send you and Mrs. Hevesy his kindest regards. In thehospital Prof. Faber is looking after his condition. Next thing I have to
inform you is that I have tested the all uranium minerals for 93‑96. But I
could not find any indication. I am very sorry for Mrs. Hevesy who has been

15
unable to get the writing‑table. Next step, if you want to take at all,will be as followsー：1) Fractional crystallization of Uranium and testwhether we get any
heavier fractionwhich contains higher elements. This is under the
supposition that percentage of thehigher elements is very small,
although they exist inUranium.
2) Under the supposition that they donot exist inUranium,wemight try
Th, Bi and Tlminerals. This is to find out themother substance of
these elements. Thismother substance, if it exists at all, might bealso the beginningof the group in the blacket of Bohr s table.
1) means the laborius work, 2) means the small possibility. What do you thinkof it? Or have you any other li
ne of search in view?
Prof.Nagaoka came here at themiddle of last month. Au‑business was thecentre of our conversation. I asked him to get at least one percent Au,
otherwisewe are not surewhether it is impurity or real transmutation.

Chez Mme Fonterme
95 Bd. St.Michel
Paris ve.
16thAug. 1927.
My dearProfessor Bohr,
After having spent about ten days in Germany, I arrived here yesterday
evening and amstayingprovisionally in the above pension.
I must thank ever somuch Mrs.Bohr and yourself that I have been able tospend most interesting and useful years in Copenhagen, especially an amusing
week inTisvilde just before I leftDenmark. Those events which I experienced
in connexion with the Institute will influence me throughout whole my life.
Theywill remain as a whole a happy recollection.
As regards the paper of Aoyama,Kimura and myself, I left a typed copy on
Dr.Klein s table. I found somemistakes in it and made a markwith a pencil.
When the proof comes,please correct those points; or please send the proof to

1
6
me to the above address together with that typed copy; then I shall correct
chem and send it back to Berlin. Please arrange things as it is mostconvenient for you. As regards the number of separate copies, we should liketo have 120 copies for our own account besides thosewhich ought to bekept in
the Institute. Please let them send the bill tome.
I met Pauli in Hamburg; he toldme t
hat he and Jordan had success in thequantum electrodynamics in putting space and time on the same footing so far
as the free space is concerned.
I am now exclusively learning the French language which is quite new tome and is as difficult as any other European language. If I have a good
progre邑s in language this summer, I might come next winter toHamburg to learn
theoretical things fromPauli. It depends onhowquick I can absorb French.
Please remember me toMrs.Bohr and your family.
With best regards
Yours faithfully
Y.Nishina

Chez Mme Jenicot Drapier
Nid Joyeuse, Berck‑Plage
France (Pas‑de‑Calais)
1. Sept. 1927.
畑

Dear Professor Bohr,I thank you very much indeed for your very kind letter of the 27th Aug.
together with a cheque for Kr. 2500(Frcs 16891.
90), 句hichwere forwarded here
to me yesterday. Everybody has left Paris and in order to get a good teacher
in French I came here a few days ago. It lies on the French coast of the
English Channel and not far fromBoulogne.
As regards the R
a
s
k
‑
l
!
)
r
s
t
ed Foundation, it is a quite unexpected matter tome. I thought I have already received allwhat was granted to me and I neverthought of receivingmore. I hope there is no mistake in the communication to1
7

you on the part of the secretary of the Foundation. I feel as if I received athingwhich is not due to me.
I know I continued to stay inCopenhagen long after the termintion of thestipend, but I intended it onmy own expense. I really do not knowwhether I
should receive this sum.
I should be very much obliged to you if you would let me know youropinion about thematter ‑‑‑whether I sould receive it or it should be better
spent in some otherway in Copenhagen.
I suppose you are very busy just before you leave for Como and I amvery
sorry to give you this trouble but I am really at a loss what to do. Perhaps
youwill tell thematter to Kronig, who willwrite tome.
I thought to come to Como and have pleasure of seeing you there. I madeinquiries about the meeting but I do not get any answer, and I understand themeeting is perhaps only for those who are invited, therefore I shall not comethere.
I thank you very much for your kind words that I am always welcome in
Copenhagen. I shall perhaps come toHamburg inNovember. If so and if I can,I shall come toCopenhagen once again before I leave Europe.
Hoping you will have a nice journey to Como and an interesting meeting
there.
With best regards toMrs. Bohr and yours邑lf'
Yours faithfully
Y. Nishina
F・s. I stayhere until the 5th Sept. and after that the following address
will findme somehowor other:
Chez Mme Saroi.handy
1
02 Avenue des Ternes
Paris (
1
7 ).

1
8
Paris, 2
1.1
0. 27.
Dear Professor and Mrs.Bohr,
A wanderer is going to move and these are the last few lines to you fromthis country.
Every country 1¥nd every place has its own characteristic charm so is
Denmark and so is Paris. On the first day of my arrival in a country as a
stranger, what attract my attention are those aspects of things which arecontrary to my habitual conducts and thought
s in the preceeding place. But
1
¥
f
t
e
r a while, I begin adapting myself to the newcircumstances, and one day,to my surprise I discover a small beautiful spot in what previously seemed tome disgustful. The charm gradually predominates and ,consequently the disg
ust
disappears. At last I feel at home amidst t
he t
hings which were so annoying
at first. This is perhaps the psychology of a wanderer. In such a manner I
have spent last twomonths here and at the eve of daparture I even feel a sortof sorrow.
As regards the French language, I have only arrived at t
he conclusionthat two months are not sufficient forme to digest t
his lenguagewhich is ofa different family fromwhat I know.
I shall leave here on the 25th inst
. and after visiting Hevesy,Fues andsome other people onmy way, I shall arrive at Hamburg on the 30th Oct. ThusI shall be a little nearer to you and this thought will consolate me,until I
adjustmyself to t
he new situation of a newplace.
How is theweather inCopenhagen? Since the day onwhich the summer time
was terminated, we have been having a summer weather in Paris −ー− irony of
theNature, somebodymight say. ・・With best regards and kindest remembrance to yourself and your fa
milyYours Sincerely
Y.Nis
hina

1
9
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DearProfessor Bohr,I arrived here nearly a fortnight ago, but havehad so much to do that I
havenot beenyet able to beginmywork.
To‑day I have met Aoyama who came here from Leiden for a day s stay.
Through my talk with him I have found an irreparable fault which I committed
in the last paper of Aoyama, Kimura and myself. You will see what it is fromletters to Prof. B
i
6
g
g
i
l
d and Prof. Scheel, both of which I enclose herewith,
as well as Berichtigung . They are all copies and you need not send themback to me.
Prof. B
s
,
l
g
g
i
l
d has been always very kind to me in other occasions too andI amvery sorry forwhat I did or ratherwhat I did not do.
I write this letter to you only to inform you how much Prof. B￠ggild
helped ourwork and also to informyouwhat I have done for compensation of myfault.
Aoyama sends you and your family, best regards, he has a very bad
conscience for not having written to you. He will stay in Leiden until theend of January and thenwill leave there forJapan.
I hope I shall be able to come to Copenhagen at Christmas time for about
a fortnight. It depends on the work which I shall do here. As soon as I
decide whether and when I come, I shall write to you. It will be my greatest
pleasure again to see you, your family and my old friends in the Institute.
With best regards to your family and yourself
Yours Very Sincerely
Y.Nishina

20
bei Frau Zutermann
Beneckestr. 22 II
Hamburg, Germany, 1
1
.1
1
.2
7
.
Dear Professor B
!
l
!
g
g
i
l
d
,
I am writing this letter in order to apologize you for my irreparable
fault. Aoyama, Kimura and myself, who worked together in ProfessorN. Bohr S
Institute lastwinter, have recently published a paper in the "Zeitschrift fur
Physik dealing with the dependence of the X‑ray absorption spectra on thechemical compounds", a separate copy of which I send you by a separate post.
In that paper I am very sorry that we did not thank you for your kindness andgenerosity in supplying us several compounds which gave some very interesting
results. The fault was committed bymyself in the followingway:
I remenber that Aoyama and Kimura, who carried out chiefly the actual
experimental part of that work, told me once that you were so kind to put
several very valuable, beautiful crystals to our disposal; but 工 could notremember what crystals they were. Both of them left Copenhagen early last
spring and consequently it was my lot alone to write the paper on this work
last summer. Thus this paper waswrittenbyme in a certain absence of directconnexions between its authors, and at that time I did not realize exactlythat th邑 experimental results which we published, contained those on thecompounds, which you put very kindly to our disposal. I left Copenhagen lastAugust and now I am staying here in Hamburg. To‑day l have happened to meet
Aoyama, who has come here for a day s stay from Leiden, Holland, where he isstaying. He told me the above matter in detail and regretted very much that
we did not express our thanks to you in that paper for your such kindness andgenerosity. I was really sorry beyondwords to hear this fact. But it is toolate now and I must apologize you very much for this fault. I have at once
asked the editor of the "Zeitschrift fur Physik to publish the correction
which I encloseherewith.
Anyhow the work will, I hope, be continued in Japan and in the next
publicationwe shall certainly express our hearty thanks to you.

2
1
Apologizing you once againon behalf of all of us three,Yours Very Sincerely
Y. Nishina

Hamburg, 1
1.1
1. 1927
Physikalisches Staatsinstitut
Jungiusstr. 9.
Sehr geehrterHerr Geheimrat!
!ch mochte Sie hoflichst bitten, die beiliegende Berichtigung unserer
Arbeit bei der nachsten Gelegenheit in der Zeitschrift fur Physik" zupublizieren. Fur diePublikationwarenwir Ihnen sehrdankbar.
Mit vorzuglicherHochachtung,1hr ergebener
Y. Nishina
Berichtigung
zu unserer Arbeit Die Abhangigkeit der Rontgenabsorptionsspektren vonchemischen Bindung， von S. Aoyama, K. Kimura und Y. Nishina in Kopenhagen,Bd.44 S.
810. S.831 Zeile 9 v.
u.
lies: legungen, HerrnProf.O.B. Bjlggild, HernProf. G.v. Hevesyund
HerrnDr.J.
A. Christiansen
statt: legungen, HerrnProf. G.v. Hevesyund HerrnDr. J.A. Christiansen
S.81
6 Formel (1)lies: KCl+++‑ KCl = JAr+ + JAr++ + JAr＋ ＋ ＋ ー （JCl+ JCl+ + JCl++)
statt: KCl＋＋＋ ー KCl =JCl + JCl+ + JCl＋ ＋ ー （JAr++ JAr+++ JAr+++)22
Hamburg, 19. 2. 28.
Beneckestr. 22 II
bei Frau Zutermann
Dear Professor Bohr,How are you after you have come home? As I told you in the lastconversation which was very pleasa
nt to me, I am coming to Copenhagen. I
shall leave Hamburg on about the 1st March, and after visiting Rostock, I
shall arrive inCopenhagenon about the 4th.
I hope to learn different things and am looking very much forward toseeingyou.
Dirac s last paper was a great excitement to us here. Gord.
on has worked
out the case of Hydrogen atom and obtained the complet・e Sommerfeld formulawith a little different numeration of j. Dirac s letter to Gordon tells thatDarwin has obtained the Sommerfeld formula, too. I suppose you have alreadyheard of it.
This is just to tell you that I amcoming on the above date.
Please rememberme toMrs.Bohr.
With best regards and expectation of seeingyou again,
YoursVery Sincerely
Y. Nishina

内J

06

．

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OD

−

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−
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Dear Professor BohrThank you very much for your kind message through Miss Schufti. I havebeen back here for about a week and been thinking of writing to you, butcaught a cold and been lazy.

23

Our work has not come to a definite and we shall start again when Klein
comes back here at the middle or the end of this month and hope to finish it
in September so that I shall be able to leave here at the end of Sept. or at
the beginning of Oct.
I received the other day・a letter fromProfessorNagaoka,whowill arrive
in Berlin in a few days. He is going to attend an international me邑ting of
wireless matters, which will be held in Brussel in Sept. He wrote that heperhaps comes to Copenhagen but that will be after the meeting. I wrote to
him to come here some time in Sept.
I received also a letter from Takamine, who sent you kind regards andasked me to send you a picturewhichhe took someyears ago.
With best regards toMrs. Bohr, your family and yourself,
Yours Very Sincerely
Y.Nishina

Paris, 21st Oct. 28
DearProfessor and Mrs.Bohr,
It is just a fortnight ago since I left Copenhagen, from which myexistence is gettingat a greater and greaterdistance both in space and time.
The further I stand from it, the better I see things in their proper
proportion, and I feel a great thankfulness to you for lettingme stay inyour
Institute for so many interesting years. Owing to my inability I have notaccomplished anything valuable in physics during this long stay. The more I
think of it, the more grateful I am to you for my stay which has only beenpossible through your kindness towards me.
Next I thank you very much that you have read through my note t
o Nature
and made some corrections, about which Kleinhas written to me.
Lastly I thank you that you came to the station when I left Copenhagen.
It was very nice for me to have travelled whole the way through together with
Prof.Billmann.

24

Since I arrived here I have spent most of my time for learning French.
One cannot, of course, learn much in such a short time, but it may be better
thannothing.
By the time this letter reaches to you I shall be in England where I
shall stay for about a week and then take a steamer for America on the 31st
Oct.atPlymouth.
Now it is the time to say good‑bye to Europewhere I have spent fruitlesssevenand a half year, which is not a small part of a man s life.
I wish youa best luckandhealth andhope to seeyou inJapan.
With best thanks and kindest regards to your family and yourself,
Yours Very Sincerely
Y. Nishinap.
s. How is the baby? I hope he is getting better.

a

d

−

・・

0・

VJ

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︒
命

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ι

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DearProfessor and Mrs. Hevesy,
Now I am onmyway back to Japan and have come here. I regret very muchthat I have had no time to see you once more before I leave Europe. I haveleft somany regrets inEurope and this is one of them.
I am leaving here on the 30th inst. and take a steamer on the 31st inst.
at LeHavre, France. This will carryme to NewYork. After spending 4 weeks
in America, I shall leave San Francisco on the 5th Dec. arriving at Yokohama
on the 21st Dec.
This is the last letter I write to you while I am in Europe, where I
spent 7 years, which is not a small part of a mans life. I am very thankful

25
to you for your kindness you extended tomeduring this long stay.
I hope you will keep yourself in t
he best of yourself and wish you goodluck.
With best regards and remembrance,
Yours Very Sincerely
Y.Nishina
p.
s. I shall give you my address inAmerica, if it is of any use to you.
Consulate‑General of Japan
165 BroadwayNewYorkCity,N.
Y.
which I shall call on,on about the 9th Nov.
Consulate‑General of Japan
1533Tribune Tower
435North MichiganAve.
Chicago, Ill. U.
S.
A.
which I probably call on, on t
he 20th Nov.
Consulate‑General of Japan
22 BatterアStreet
San Francisco,Calif. U.
S.
A.
which I call on, on the 4thDec.
After the 21st Dec.
The Institute of Physical andChemical Research,
Hongo, Tokyo, Japan.

Le Havre, 31. Oct. 1928
Dear Professor Bohr,I thank you very much indeed for your very kind letter together with athorough testi
mony. I am sorry to see that my last letter induced you towrit
e this long document which must have taken youmuch time, and so much themore I am indebted to you for it.

26

At present I do not think I have any opportunity of using this testimony
in Japan, but there might be some cases in the future, where it is very
valuable to me. Even if it has no practical use, it is really a testimony ofyour appreciation of my effort during those years past,which although has had
little fruit in my opinion. I shall therefore keep it for myself and it will
always remind me of the years I spent in your Institute and it will everencourageme in time of depression.
In half an hour this steamer Rochambeau is going to leave this harbour
and I shall leave Europe. I shall once more thank you from the bottom of myheart and send you mybest wishes to you all in the Institute and your family.
With best remembrance and kindest regards,
Yours Very Sincerely
Y.Nishina

27
Y. Nishina s Letters to N
. Bohr, G.Hevesy and Others
To

Date

From

Page

N
. BohrN. Bohr
G.Hevesy
G.Hevesy
G. Hevesy
G.Hevesy
G.Hevesy
D.Coster
G. Hevesy
G.Hevesy
G.HevesyN. BohrN.BohrProf.andMrs.Bohr
N.BohrO.
B. Boggild
Geheimrat
N.BohrN. BohrProf. andMrs.Bohr
Prof.andMrs.Hevesy
N.Bohr

25/III, 1923
4/IV,
1923
13/X,
1924
24/X,
1924
18/XI, 1924
21/XI
, 1924
29/XI, 1924
6/II,
1925
17/VII, 1925
12/VIII, 1925
17/IX, 1925
16/VIII, 1927
1/IX,
1927
21/X,
1927
11/XI, 1927
11/XI, 1927
11/XI, 1927
19/II, 1928
8/VIII, 1928
21/X,
1928
26/X,
1928
31/X,
1928

Gottingen
BerlinCopenhagen
Copen
hagen
Copenhagen
Copenhagen
Copenhagen
Copenhagen
Copenhagen
Copenhagen
Copenhagen
Paris
Pas‑de‑Calais
Paris
Hamburg
Hamburg
Hamburg
Hamburg
Copenhagen
Paris
LondondeHavre

l
2
3
4
6
7
8
9
10
12
14
15
16
18
19
20
21
22
22
23
24
25

28

Corrigenda
Publication No.
20.
"Nishina s Correspondence with N.Bohr and Copenhageners 1928‑1949
p.
3,1. 17: F lledparken+ F.
elledparken
p.19, 1. 17 from the bottom:Nord Jylland + Nord S~.ellandp.
22, 1. 8: I so often written+ I have so oftenwritten
Publication No.17.
G.Hevesy ‑ Y. Nishina. Correspondence 1928 ‑ 1949"
p.24, 1. 6:Cyklotron + Cyclotronp.27 (cover), 1. 1
1: (Post Card) + (Postscript)