Monday, July 13, 2015

From Fujioka's Fluid Drop Model of Atoms to Einstein–Arakatsu Relationship

I have made a lot of exchanges with Bill Streifer (a researcher and freelance journalist on Intelligence, nuclear work and North Korea) at the Quora site from July 9 to 13, 2015. Most part of our exchanges is reproduced here by Bill's permission.

Bill: Was Prof. Yoshio Fujioka's "fluid drop" model of the atom known as ekiteki?
And if so, why?

Tatsuo: I haven't learned about Yoshio Fujioka's "fluid drop" model of the atom but guess that if he proposed such a model, it should have been called "ekiteki" model. "Ekiteki" is the Japanese word for "fluid drop" (eki=fluid, teki=drop).

Bill: Prof. Ayao Kuwaki was a Japanese scientist and a friend of Albert Einstein. When did he die, exactly?

Tatsuo: According to the information page of him in "Wikipedia" (Japanese edition), Ayao Kuwaki was born on September 9, 1878, and died on May 16, 1945.

Bill: At the end of the war, an American airman met a man who claimed to be a student of Einstein in Germany. When I learned of Kuwaki, I suspected it might have been him. But now I see that's not possible since Kuwaki died in May 1945 and the "meeting" took place in September 1945.

Tatsuo: Sure, the student should not have been Kuwaki.

Bill: He might not have been a graduate student of Einstein, but he may have attended Einstein's lectures in Germany. Can you guess who he might have been? [And he lived in northern Korea in 1945!] An Einstein scholar is not willing to guess.

Tatsuo: I have no idea about that person.

Bill: If you provide a number of possibilities, I'll check each one. Did Hideki Yukawa study under Einstein?

Tatsuo: No, Yukawa didn't study under Einstein, but they met each other for the first time in Princeton on the former's return trip from Europe in 1939.

Bill: Einstein wasn't in Germany very long. I wonder if any Japanese or Korean scientists studied under Einstein when he taught there, or even attended his lectures.

Tatsuo: The Japanese physicist Jun (Atsushi) Ishiwara seems to have studied under Einstein in Germany (石原純 - Wikipedia). Ishiwara worked as an interpreter when Einstein visited Japan in 1922.

Bill: Thanks. Did Einstein have other Japanese students or followers in Germany? Kuwaki appears to be a little too old. I'm looking for a Japanese scientist who lived until 1946 at least.

Tatsuo: I don't think that Einstein had other Japanese students or followers in Germany.

Bill: I know of another.

Tatsuo: You Know? Who is he?

Bill: Dr. Bunsaku Arakatsu.

Tatsuo: Oh, Bunsaku Arakatsu was a teacher of my teacher and an experimental physicist. So, I didn't think he had studied under Einstein. Wikipedia page for him (Japanese edition) writes that he studied in Europe (Berlin, Zurich and Cambridge) for two years from 1926. It must have been a short time during this period that he studied under Einstein. By the way, his look is similar to Einstein's in some photos of him.

Bill: Can you find any photos of Einstein and Arakatsu together? If you can, please send them to
Is your teacher still alive? If so, could you ask him if Arakatsu or Yukawa visited Konan (Hungnam), Korea during the war? By the way, Konan and Hungnam are the same place, Konan is the Japanese pronunciation and Hungnam the Korean pronunciation.
You might also be interested in knowing that my article about an Austrian chemist who worked at Konan for more than two years (1935-1937 & 1940), will appear in a book being published by the University of Vienna Korean Dept. later this summer. The name of my article is A Letter from Korea.

Tatsuo: I don't have any photo of Arakatsu.
My teacher Kiichi Kimura at Physics Department, Kyoto University died in 1992. I haven't heard of Arakatsu's or Yukawa's visit to Hungnam (Konan), Korea. However, Arakatsu was associated with another Konan. Namely, he was the president of Konan University in Kobe, Japan, after his retirement from Kyoto University. Konan of Korea and Konan of the university in Kobe are different from each other when written in Chinese characters. The former Konan is written as 興南, and the latter, 甲南.
I have not so much interest in the history of science in Korea. However, if you write about some history of physics in Japan, I would like to read it very much.

Bill: I am familiar with Kimura. I am also aware that Konan, Japan is different than Konan, Korea.

Tatsuo: May I quote our exchanges made here these days in one of my blog sites written in English? Some friends of mine might be much interested in our exchanges.

Bill: Yes, that would be fantastic. And if anyone has any questions or comments, they can contact me directly at

Tatsuo: Thanks a lot for your permission.

Bill: Stay in touch.

—A few days later we had additional exchange as given below.—

Bill: You can add this: According to page 15 of the book Uranium Matters: Central European Uranium in International Politics, 1900–1960 by Zbyněk A. B. Zeman and Rainer Karlsch, the Japanese physicist, Dr. Bunsaku Arakatsu "studied at Berlin University ... under Einstein, becoming a member of Einstein's close circle of friends."

Bill: I returned to the original document, and I am now convinced that the American airman met a Korean scientist, not a Japanese scientist in Korea in September 1945. But it's still interesting that Arakatsu was a close friend of Einstein, so all of this work wasn't for nothing.

Tatsuo: I've been on a trip to my hometown since Tuesday and am writing a belated reply. Thanks a lot for your additional information. We surely have gotten a good fruit.

(Last modified on July 29, 2015)

1 comment:

Bill Streifer said...

I am doing research on heavy water production in Japan, from about 1935-1960.

At first, the Japanese population was reluctant to pursue heavy water research (for obvious reasons). Eventually, however, Japanese industry wanted to get back into heavy water production to produce energy (under strict U.S. Occupation guidelines, and by 1954-1957, scientists and the owners of plants, who were involved in heavy water production during the war, wrote on the subject.

I also know that Dr. Bunsaku Arakatsu, the head of Japan's atomic program at Kyoto Imperial University, understood the value of heavy water to transmute uranium into plutonium. And in 1946, he explained to the American press how far he advanced during the last days of the war.

By 1950, I believe Arakatsu was the president of Konan University in Kobe, Japan. I am wondering if Arakatsu ever discussed his atomic program or heavy water again. I am having difficulty contacting Konan University by e-mail (even in Japanese) but if I could, I would ask if he ever wrote on the subject again.

If anyone knows the answers to any of these questions, please contact me at

Thank you,
Bill Streifer