The Manhattan Project

Spencer Weart's Interview

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Spencer Weart's Interview

Spencer Weart is a historian of science. Originally trained as a physicist, Weart served for many years as director of the Center for History of Physics of the American Institute of Physics (AIP) in College Park, Maryland. In this interview, Weart discusses the French nuclear program, starting with its origins with Marie and Pierre Curie. He examines the prominent role of their daughter, Irene, and her husband, Frédéric Joliot, who together won a Nobel Prize in 1935 for their discovery of artificial radioactivity. Irene and Frédéric’s work made enormous contributions to the development of nuclear physics during the late 1930s. Weart goes on to explain how, during World War II, key members of the French program became part of the Manhattan Project, as well as Joliot’s role in the French Resistance. He concludes with a discussion of the postwar nuclear program in France.
Date of Interview: 
May 11, 2018
Location of the Interview: 
New York
Transcript: 

Cindy Kelly: I'm Cindy Kelly, Atomic Heritage Foundation. I am in Hastings-on-Hudson, New York. It is Friday, May 11, 2018. I have with me Spencer Weart. My first question is to ask him to say his name and spell it.

Spencer Weart: I am Spencer Weart, W-E-A-R-T, like heart.

Kelly: Great. Spencer, you are a physicist. You had an early career in science. Tell us about your childhood and a little bit about how you became interested in science and science history.

Weart: I grew up in a suburb of New York City, Larchmont. Upper middle-class family, good education, good schools, good science teachers. When I was taking physics in high school, Sputnik came along. Space was very exciting, science fiction, all that kind of thing. I thought, “Okay, I'll be a physicist.”

I went to Cornell. The physics department there was a very good one. Then from there went on to a standard career, University of Colorado, Boulder—not the most standard source, but it was near the mountains and the skiing, which was always probably the second most important thing in my life, until of course my wife and family came along.

The going thing in Boulder was solar physics, which later on contributed to my career in the history of science because I became interested in climate change. But solar physics at the time was an exciting field, a lot of space stuff and so forth. I got my degree there. I went to some solar eclipses, which was very exciting. I went to CalTech jointly with a fellow at the Mount Wilson Palomar Observatories. I did solar physics work and worked on various solar telescopes and so forth, published some papers, one of which was reprinted and became fairly widely cited.

But the next career opportunity for me probably would have been to go to NASA to work on a space solar telescope. It did not appeal to me. The field of solar physics did not strike me as a very exciting field. As it turned out, the solar telescope that I would have been working on was delayed for many years, and finally scheduled to fly on the next flight after the Challenger. Probably my sense that this was not a good career path had some validity behind it.

Meanwhile, all of my life I had been interested in history. It had been my second major interest. I remember when I was at Cornell, I took a graduate level seminar. The professor at the end of the term asked me what I was going to do. I said I was going to be a physicist. He said, "Oh, what a pity. Well, couldn't you be a historian of science?"

I thought, “What a ridiculous idea!” But then I thought, “Well, maybe so.” At that time, I was courting my wife. She introduced me to a person who was an anthropologist, and introduced me to Thomas Kuhn and other writings and history of science. I said, “Okay, maybe that's a career path.”

I was in the lucky generation. I was born in 1942. There were huge opportunities, as the Baby Boomers crept on us demanding education. I was actually able to take some time off and go back to school at the University of California at Berkeley, and in effect take a second Ph.D., although University of California wisely doesn't give Ph.D.’s to people who already have them. I became educated in history of science.

As I was beginning to look for a job, one of my professors there, Roger Hahns, said, "I have an interesting proposition for you. There is a man in Geneva called Lew Kowarski, who wants somebody to arrange his papers, and maybe he wants somebody to write his biography, I don't know. But he wants somebody to arrange his papers, and I have some money for you. 

This is very typical, and it shows up all the time in the French story also again and again. Some young person finds a patron who digs up some money for them to go and do some research.

I went to Geneva. I went to Lew Kowarski, and got ever more fascinated by the story of the French nuclear energy developments.

Kelly: That was an excellent introduction to our main topic here, which is French nuclear developments. I think that the best place to start is with Marie Curie and her husband, and what they did in terms of creating the foundation for atomic science.

Weart: It all starts with Marie Curie—a vivacious, very determined redhead from Poland. Went to Paris, as many Poles did because it [Poland] was under Russian control at the time. It was the only way that they could advance, even for a man, let alone a woman.

She lived in a garret, practically starved, made her way up, found patrons in the usual fashion, and eventually managed to carve out a scientific career for herself. Married Pierre Curie, who was already a very distinguished person in the French scientific establishment.

As part of her development of science, came across this very exciting new thing by [Henri] Becquerel, which was one of the patrons and older figures in the French establishment, this thing that they were beginning to call “radioactivity”. She decided to pursue it.

At one point, her husband Pierre joined her because he was equally a brilliant scientist and in particular had a devised instrument that could measure radioactivity very well. Jointly—but with Marie as the driving force in this particular case—they discovered radium, which immediately made an enormous impression on people. Here was this mysterious force of energy that glowed in the dark. It had perhaps spiritual powers. It certainly had powers to heal, or at least to cause bodily changes and so forth.

As Pierre quickly recognized, it gave off heat, which means that there was a source of energy in here. In fact, it seemed like an endless source of energy, energy that as people gradually came to realize had been in the nucleus of the atom since the creation. Immediately, not so much Pierre and Marie, but many other scientists, began to explain that this could do almost anything you like. There could be the transmission of the elements, new alchemy. There could be an endless source of energy. There could be enormous weapons. People, when they think of new energy sources, pretty quickly think of weapons.

By say 1910 and certainly by 1915 or 1920, all of these ideas, nuclear reactors, atomic flying cars, atomic bombs, were all out there in the world. This naturally contributed greatly to Marie's renown. Pierre's too, but of course he died early in a tragic street accident.

Marie Curie became the iconic nuclear scientist. Not just the iconic women's scientist, which was also the case, but an icon of the progress of science.

Kelly: Okay, in 1925, she hired an elegant young man with little training in scientific research whose name was Frédéric Joliot. Tell us about this man.

Weart: Frédéric Joliot, Fred, was an engineer. He came up through the normal French circles. It was only because one of his teachers, [Paul] Langevin, who was one of the senior figures in the Curie circle—and in fact Marie Curie's former lover, as it turned out, and close friend—recognized that Joliot had something more than the normal engineer. He referred him to the Radium Institute, which Marie Curie had founded with the help of the other French establishment figures. Joliot went in and started to do some research there.

It soon became apparent that he was not only a very personable and dynamic young man, but a brilliant scientist as well. He was very good with people. He was very good with instruments. He was very good with all of these things.

In the Radium Institute, he encountered one of Marie and Pierre Curie's two daughters. They had an artistic daughter who became a well-known novelist. They had a scientist daughter, Irene, a couple of years older than Joliot. They had things in common. They shared their French scientific culture. They shared political views, which were what we would now call mildly on the left, progressive, vaguely socialist, but just vaguely. Their main political views were that science was a great thing and should be supported. She, too, was a brilliant scientist.

They were thrown together. Fred was very handsome. Irene was a more serious person. They got married. People in the French scientific establishment—gossiping as the French always do—will say, “Oh, Fred was just trying to advance his career. He was the prince consort, Irene being the princess,” you know, the daughter of the queen and so forth. But the French loved to gossip, and nobody ever told me that there was any problem in their marriage. As far as one knows, it was a completely successful marriage right to the end. 

After Marie Curie became famous, she became also a symbol for the need of scientists—in particular, French scientists—for money. Science in the nineteenth century had been a matter of individuals with a little support here and there from philanthropists, or from their family money, and so forth. By the early twentieth century, you needed more money. You needed more scientists, and the scientists needed more materials.

In particular, Marie Curie needed radium, which was a very expensive thing. There were some possibilities for hooking up with industrialists, but it was mainly from philanthropists and from the French government that the French scientific establishment sought money. Marie Curie became very useful to them, as this famous and notoriously selfless and dedicated figure going around in her black dress to ministers and to philanthropists and so forth and asking for money for science.

The result eventually was the Radium Institute, which was a whole building on its own in the Latin Quarter near the Sorbonne, plus funding to bring in young people such as Joliot.

Kelly: Joliot almost quit the field of science in 1930, when he wasn't able to find a teaching position, a position in a college. That relates to what you just said about the funding.

Weart: Yeah, it was a constant struggle for funding. If you wanted to do science competitively on an international scale, you needed to bring up more and more young people.

The French scientific establishment had a very difficult time doing it. Of course, the First World War had wrecked the economy. Then by 1930, the Depression was in play. The French government, in what we now recognize as a completely futile thing, kept cutting its funding, and therefore getting less taxes and therefore cutting its funding again.

There was very little government money. Philanthropists were cutting back. Sort of by the skin of his teeth, thanks to great efforts by Marie Curie and by Langevin and others, that he [Joliot] managed to secure some funds to keep going.

Kelly: Can you tell us a little bit about Ms. Maloney, this American journalist?

Weart: Right. Mrs. William Maloney, as she liked to be called, Marie Maloney, heard somewhere that there was many times more radium in the United States than Marie Curie had in her lab, the United States being a rich country and France not supporting its science. She invited Marie over for a term.

Marie Maloney was a journalist. She was an editor of a woman's magazine, very good writer herself, a wonderful publicist. Marie [Curie] went on a tour, shuttled around from place to place. Marie Curie was shy, but she was willing to stand up and read her lines and say that science was necessary.

They said, “We are going to get Marie Curie a gram of radium. We will raise enough funds to get her a gram of radium.” They did that mostly from Americans, including children. Little girls sent in their pennies. They raised the money to buy Marie Curie a gram of radium. 

Of course, French philanthropists and the French government, shamed, had to give some comparable support. It was one of the things that undergird the Radium Institute.

Incidentally, the work for which Joliot and Irene Curie won the Nobel Prize was done with a part of that gram of radium.

Kelly: Do you remember how much money the Americans raised?

Weart: I don't remember offhand. On the order of a million dollars. You could look it up. A lot of money in those days.

Radium was wanted for medical uses. Pierre Curie carried around a bit of radium in his pocket, and found that he got a skin lesion next to it. That was the first sign of what radium could do. It turned out to be useful in treating surface cancers, skin cancers and things like that. 

I should also say that the medical uses of radium were also a main impetus behind all the funding for the Radium Institute. Throughout their careers—Pierre and Marie Curie and then later on Joliot—throughout their careers, the medical uses of nuclear energy were one of the main things that they talked about, one of the main things that they used to raise funds for.

It's worth saying that today every year, more lives are saved by nuclear energy than were lost at Hiroshima by a factor of ten.

Kelly: Per year?

Weart: Yeah, per year. They weren't mistaken in looking to the medical uses.

Kelly: Before the war, there were a lot of different countries who were on to what might be inside the atom in terms of energy and how to harness it. Can you briefly talk about where the French were in terms of their efforts, and how they progressed?

Weart: Yeah. There was international competition. The leading people were obviously in Britain, Germany, and France. France being primarily because of the Curie family, that was more restricted than in Germany and Britain. They [scientists in Germany and Britain] were scattered around a little more. There was a team in Italy under [Enrico] Fermi, thanks only to Fermi and to a senator who managed to dig up the funds for them. Then there was the rising power in the United States, which was more and more economically strong and had more and more scientists scattered around. Then there were people elsewhere. Niels Bohr in Copenhagen. There were people in Austria. There were people in the Soviet Union who were doing good work. 

There were a lot of people going around. They were exchanging papers. They were meeting in conferences. People even went to the Soviet Union to attend conferences. There was an international community of friendly rivals. They would all be very happy to get together and exchange ideas with each other, but they also would be very happy to go home and try to get their paper published first.

Kelly: What did Joliot contribute? What was he doing with his team?

Weart: Joliot first did some research on his own, and then he very felicitously teamed up with Irene. Joliot was the brilliant physicist. Irene was the methodical and persistent chemist on the team, which made a very good team for the kind of radioactivity research that people were doing at the time. 

They began to produce results. Nothing epic-making, but serious results that got them, in fact, invited to one of these conferences, the Solvay Conference, which is one of the places where all of the nuclear and quantum physics people got together. They had reached a fairly prestigious level through the kind of publications that everybody was doing—finding a little bit about this, finding a little bit about that.

They almost found the neutron. They found a peculiar phenomenon which they couldn't explain. [James] Chadwick in England explained it. “Oh, this is a neutron.” 

“Darn, we missed it. If we had only been able to figure it out!”

Then they found some other thing. “What is this going on? We found it,” and then somebody else explained, “It's the positron.”

“Okay, darn, we missed the positron.”

Then they found another peculiar phenomenon. What you did in radioactivity in those days was you bombarded particles with other particles and saw what came out and tried to figure out what it told you about what was going on inside the nucleus. They bombarded alpha particles, which came from this radium that had been donated to Marie Curie. They bombarded aluminum foil with it, and positrons came out.

“What is going on in here?” They had theories about it. “Maybe the neutron is actually—an atomic nucleus is the neutron plus a positron.” They took this to the Solvay conference, and people pooh-poohed it and so forth.

But Niels Bohr took them aside and said, "Keep on with it. Don't be discouraged." They went back and they finally, through kind of an accident, found—it's like Becquerel with his radioactivity, when he was trying to find what was happening by shining sunlight on something he thought was phosphorescent when it was a cloudy day. They continued to emit rays.

The same thing happened with them. At one point, Joliot took away his source from the aluminum foil, and the Geiger counter continued to tick. Something was going on in here. In fact, what they found out was that they had made the aluminum radioactive. They had changed the aluminum into—well, as it turned out, into radioactive phosphorus. Can this be true?

They call on Irene Curie to find a way to extract phosphorus from aluminum in three minutes before the radioactivity decayed. She managed to do that. They found that it really was radioactive phosphorus.

At this point, Joliot started dancing around the room. "With the neutron, we were too late. With the positron, we were too late. Now, we are on time." 

This won them the Nobel Prize for the discovery of artificial radioactivity, that you bombard with certain elements with other elements and you can make an entirely new element which is radioactive, which was immediately recognized as something that could have profound medical uses. 

In Great Britain, [Leo] Szilard was stepping off a curb one day, and a flash of insight came to him. “What if you can make a chain reaction with this? What if you could bombard something, and it bombarded something else in turn, and made more of it?” Could you make an atomic bomb?” He kind of kept that to himself.

But this was one of the consequences of the discovery of artificial radioactivity, actually predicted in 1913 by H. G. Wells in a novel about atomic bombs [The World Set Free].

It's worth pointing out that this [winning the Nobel Prize] did great things for the Curie Institute and for radioactivity and for women in science, and all of those kinds of things. What a romantic story! Pierre and Marie Curie won a Nobel Prize by working jointly. Their daughter and son-in-law won a Nobel Prize by doing joint research. It never happened before, and it never happened since. It's a unique circumstance, a wonderful romantic story.

Of course, it helped the French scientific community in going about to increase their contacts with industry and increase their contacts with politicians, all in the primary aim of increasing funding for science, which to them was the single best route to a wonderful future. 

Kelly: After that prize and such, how did their lives change? Were they able to get more funding?

Weart: There was a lot more money, but not only because of the Nobel Prize. This was also the years in which the Popular Front came to power. The Popular Front represented to a substantial extent the ideals of the French scientific community—through no coincidence, because these people had all gone to school together at the École Normale. They were all leftist leaning. They all believed in progress, the Third Republic ideal of liberating people from clerical superstitions through the advance of rationality and science. It was entirely natural for the Popular Front to pour extra funding into science. Indeed, Irene became a secretary for a while in the Popular Front government.

Meanwhile, Joliot was busy using all those funds to start building up his laboratories. The great new thing was atom smashers, very large and expensive devices. He got advice from Ernest Lawrence in Berkeley on how to build a cyclotron. He got a professorship, again with Langevin's help. He got a professorship at the Collège de France, which is the most prestigious ancient scientific institution, and began to tear down walls and bring in workmen to put in all of these laboratory things. For the next few years, he was primarily administrating the development of more nuclear energy labs.

Kelly: You had mentioned the Radium Institute. That was Marie Curie's. E. O. Lawrence’s, the Rad Lab.

Weart: Yeah, his Radiation Lab at Berkeley.

Kelly: Was there some sense of competition here, between the Radiation Laboratory at the University of California Berkeley?

Weart: Again, this is the friendly competition. “It's great that somebody discovers artificial radioactivity, but nice for us that we were the one to find it first.” Cyclotrons, “Let's build cyclotrons and see who can discover things with them.”

Lawrence sent people to other labs around the world to help them to learn how to build cyclotrons. He sent people to Joliot to help them work out how to build a cyclotron. This was a cooperative enterprise in which we helped each other to make discoveries, but you just wanted to be the one who made that discovery first.

There was occasionally some kinds of bad feelings in particular that happened that developed some bad feelings between Irene and the team in Berlin, Lise Meitner and so forth. When Irene came up with some results that Lise Meitner said, "That's all wrong. It's ridiculous. She's stupid." But it turned out in this particular case, Meitner was wrong. There was a certain amount of bad feeling that developed, which eventually leads into the discovery of fission story.  

While Joliot was busy with his administrative stuff, Irene, after she left the government, went back to her work doing radiochemistry. She came up with some very peculiar results that she could not explain, her and another foreign person working out there, because the Radium Institute was full of foreigners thanks to Marie Curie's Polish heritage, she welcomed foreign visitors.

With a man named [Paul] Savitch, Irene was investigating uranium, which was the heaviest element and had peculiar characteristics. People were investigating everything, again, bombarding stuff, and seeing what came out and trying to figure out what it was. She found these very peculiar results. [Otto] Hahn and Meitner and [Fritz] Strassman, who were in Berlin, thought again that she was completely wet, and she just didn't know what she was doing and couldn't do the chemistry properly. 

Irene got provoked by this and went back and did more work and more precise, meticulous, careful work, and pinned down very definitely that yes, she had found this thing which couldn't be explained. Again, perhaps if Fred had been working with her at that time, they would have solved it.

But as it turned out, it was Hahn who solved it and said, “Wait a minute. This is actually the uranium nucleus breaking in half.” What he actually said was, “Maybe it’s the uranium nucleus breaking in half.” Then Meitner and [Otto] Frisch—Meitner had had to leave Germany because she was Jewish—and with Frisch, they figured out that it was actually nuclear fission.

Again, Irene Curie was the person who put Hahn and all of the others on the trail for nuclear fission. She just hadn't made the final step herself.

Kelly: That's the trail that they had first said, “That's going nowhere,” that she had—

Weart: Yeah, she thought she was just doing her chemistry wrong. But when they redid the chemistry and they redid it, and they kept getting these completely weird results, which turns out—at the time, everybody understood that what you do was, you bombard a nucleus with the thing. You bombard it with a little thing, and other little things come out. The nucleus transforms. It spits out a little bit of itself or something happens, and you get basically the same nucleus with slight changes. It was a completely break with the normal way of doing things to imagine that the thing would just break in half.

Kelly: And also release— 

Weart: And also release energy. It was immediately recognized, you ask any physicist and you say, “Oh, a heavy nucleus breaks into two smaller nuclei.”

Any physicist in the world says, "Wow, energy will come out."

Kelly: Why is that? How do we know that?

Weart: Because E=mc2, and because if you add up the mass of the two smaller parts that come out, given the mass of these two smaller elements and compare with the mass of the uranium nucleus, you find that some mass has been lost. Where did that mass go? It went into energy.

Immediately, every physicist in the world who heard about this went into his lab and started to look for the energy that came out, including Joliot. He found it, and people congratulated him and said, "Oh wow, you have proved that fission produces energy."

He shrugged and said, "Well, everybody else in the world has already found this within this week," which was true. Lots of people did the experiment and found that energy was coming out.

Kelly: What did Joliot—this the next thing you might talk about is, what he then started to pursue in terms of trying to harness that energy?

Weart: The next thing is, “Wow, this is what people have been talking about since the discovery of radioactivity. For forty years, people have been saying that we might be able to put this energy to good use. Now, finally, we have found something that might be able to do that.” 

The basic scientific question there is whether you can make a chain reaction. This was what Szilard had realized when he stepped off the curb. If you can get one to make another and the other to make another, then maybe you can get energy. 

But the question is, if you split one nucleus and it gives out neutrons, as it turns out, and they hit another nucleus and make it split. When you make one split, you get then enough neutrons to make two split, and then four and eight and sixteen, and so forth on up. Or less than that—maybe only you split one, and then maybe another one will split. That gives you another one will split, and then nothing happens. You don't have an actual expanding chain reaction. The crucial question was, do you get a multiplication? This was, as it turned out, a difficult thing to find out.

In order to do that at this point, you needed a team. Science was getting bigger. Science was getting harder. Science was getting more expensive. You needed to have more than just one person working on it. By this time, Joliot had finished pretty much all this construction work, his cyclotron and so forth. His atom smashers were up. He was ready to turn to an actual scientific problem. This was obviously one of the biggest scientific problems of the time.

He looked around for help. The first person he came to was Hans Halban. Halban was Austrian and grew up in Switzerland, where his father was a professor. Came from a reasonably wealthy, cultured, German speaking environment. Married money so he was even more wealthy, debonair, pretty good scientist, not brilliant, but he could do the work.

Then there was another person, Lew Kowarski, who the only person I have mentioned so far that I have met actually and worked with. Lew Kowarski was an enormous bear of a man. But like some big men, very meticulous, very precise. He had been born out of wedlock between a Jew and a Christian in Russia. His father managed to get the marriage broken—it wasn't a marriage, but the relationship—broke up. Kowarski grew up in a very unsettled environment, not to mention being in Russia through the First World War and got smuggled out basically to Wilno and then from there, like so many Europeans, found refuge in the scientific community in Paris. Trained as an engineer, went on to get a Ph.D.

I can say he was also a very sharp scientist. Kowarski once asked me, he said, "You say here that I am a very good scientist. How do you know that? All of the work I did was in collaboration."

I said, "I looked at your Ph.D. thesis." His Ph.D. thesis was actually ahead of its time. He was a good scientist. He had a sharp mind.

He, like so many people, was scrambling for work. He worked for some time as Joliot's secretary with la petite dactylo [“the little typist”]. He was big. He was Joliot's “little typist,” but also did scientific research. He was getting his Ph.D. He knew Halban, who had come to work at the Radium Institute with Irene and the other people there.

He sort of came under Halban's wing. He said, "I want to learn to do nuclear physics. The heck with it.” He was an engineer for a steel pipe factory and working part time as a secretary and research assistant. He said, "I want to be a nuclear physicist."

Halban said, "Okay, let me show you the ropes." When Joliot was trying to assemble a team, Halban went to Joliot and said, "Why don't we bring Kowarski in, too?"

This is all oral history now, so we don't know for sure. Kowarski's story is that Joliot said, "You know, this could make his name. Do we want to do that?"

Halban says, "Yeah, that's okay. He's good enough." 

They formed a team and Joliot was obviously the driving force, but we can't know when you have these small scientific teams who came up with which ideas. The ideas circulate around and come out, and finally they worked out ways to try to figure out how to find out whether or not this chain reaction was possible. 

How do you find out if there is a chain reaction? Well, you have to take some uranium and you have to put in a moderator, something that will knock the neutrons around and slow them down. The only moderators that seemed plausible were graphite, carbon, and heavy water. Graphite has a problem that it has impurities. It's very hard to get them out.

Heavy water has problems that it's hard to make. You have to distill regular water. Heavy water is water that has hydrogen. It has an extra neutron on it. Because the hydrogen has an extra neutron, it doesn't absorb neutrons, so it will scatter around in heavy water indefinitely.

Uranium was hard to come by and heavy water was hard to come by, so what do you do? Well, this was the spirit of the French scientific establishment. You cooperate with industry. You cooperate with government.

Maybe I'll start with uranium. The richest uranium mines in the world are in the Congo. One has the uranium that is so rich that it made a nuclear reactor all by itself when water seeped into it a long time ago. The owner of the Congo [uranium] was the Union Minière du Haut Katanga. So they went to the Union Minière, which was in Belgium. They said, "Let's make a deal with you. We will take out some patents on our ideas. We will share the patents with you. You give us some uranium. We will make some kind of joint venture."

This is the scientists trying to get themselves embedded in the world of industry. Of course, since they were already embedded with government, they also went to the government for funds. In particular for the heavy water, the heavy water came from Norsk Hydro. There was a hydroelectric plant in Norway that produced small quantities of heavy water, just for doing research and so forth. They had been building up. They set up their distilleries. It turns out that they had gallons and gallons of the stuff that they hadn't sold. They just kept accumulating, because they had the thing set up.

At this point, they recognized that they were in a race, and in particular with Germany. This was 1939. Almost everybody was aware that a war was coming. At this point, people were aware that an atomic bomb was at least a remote possibility, if not an atomic bomb then certainly things of very grave economic importance. It became a question actually of national security.

They went to a man named Raoul Dautry, who was one of the top bureaucrats, engineer bureaucrats. He later on wound up reforming the French railway system, that kind of a person, in touch with the military in particular. They organized a mission to go to Norsk Hydro clandestinely so that the Germans wouldn't find out about it or grab it first, buy their heavy water, and bring it to France, which was kind of a cloak and dagger operation because Kowarski had a Russian accent and Halban had a very strong German accent. They were put away on an island, so they couldn't reveal any secrets until the heavy water reached France.

Then they put the uranium together with the heavy water and they found that yes, you get more neutrons out than you put in. Yes, a chain reaction is possible. This had also been recognized in Columbia [University], where Leo Szilard was. Szilard wrote to everybody saying, “If you find out that there is a chain reaction, for God's sake don't tell anybody.” 

Joliot’s people said, "You are trying to keep us from publishing this. Everybody is going to know it pretty soon anyway." So, they published the result. At this point, basically, the race for the atomic bomb was on. 

Kelly: What year was that?

Weart: 1939.

Kelly: Just months after the publication in Nature?

Weart: Yeah, the idea of uranium fission was published. Many people immediately confirmed that fission released energy. Finding that neutron multiplication was possible was much harder. That took some months, but that was I think around March or April, I am not sure, around then.

At that point, fairly soon after that, nuclear research began to go dark. It didn't take long before people hooked up with their governments and started to say—of course then the war started, which was definitive.

Interestingly, the Union Minière story has further ramifications. This of course alerted the Union Minière of the importance of its uranium stocks, which were massive. Uranium was useful mainly because you could refine radium from it, but also it could be used for industrial uses. It made nice yellow colorant in pottery, and so forth. Union Minière had a warehouse full of it.

When the war came, in probably typical Belgian fashion, they left half of it for the Germans to capture and shipped the other half to the United States. When the Manhattan Project started looking around for uranium, naturally, it went to the Union Minière. They said, "Where is the uranium?" 

They said, "Well, half of it is in Staten Island." That's the uranium that blew up Hiroshima. Again, this is traced back directly to the French initiative in forming the Union Minière.

Incidentally, the Union Minière also shipped some freight cars full of uranium to France, where they were conveniently lost on a siding during the entire war and recovered afterwards and helped to fuel the first French nuclear reactor.

Kelly: Conveniently lost?

Weart: We don't know the full story.

Kelly: Did the Germans get their half? They confiscated it and took it back to Germany?

Weart: I can't say I believe so. They never seemed to have—but of course, they also captured the mines. They owned the mines in Austria, which also produced lots of uranium. I don't know that they particularly needed it for the small research project that they had. 

The further saga of heavy water, people have made books and movies out of it. Dautry learned in a meeting that the Germans had broken through. They were going to capture Paris. One of the first things he did was to tell Joliot, "Take your team. Take the heavy water. Take everything and evacuate." They went to Clermont-Ferrand, which was supposed to be the next capital of the Third Republic. They piled the stuff into cars and got some Army trucks and drove down there. 

Very soon the word came, “You are not going to get here.” Dautry wanted to evacuate everything from France. He wanted the entire French army to move to North Africa. He was one of the true patriots. Some of the other politicians were more willing to give in to the Germans on the basis, “Better the Nazis than the communists.”

Joliot and his team were directed to go to Bordeaux, which was the last capital of the Third Republic, with their heavy water. There Dautry's people directed them to a British collier that was in the port. They took their heavy water on board and were evacuated to England, bombs falling about them and that kind of thing.

Joliot decided to stay [in France]. Joliot was a very French patriot. Halban and Kowarski, of course, did not have such close connections. 

By the way, this is worth saying—Kowarski once told me: in France, he was always a Russian Jew. When he came to the United States for a few months to teach at Boston University, he felt more welcome and at home in the United States than he ever in his life felt in France. Halban, with his German accent, must surely have felt similarly.

Joliot, on the other hand, decided to stay in France on the understanding that the Germans would not be there forever. Sooner or later, Joliot quite correctly predicted they [the Nazis] would get into war with the Soviet Union. Meanwhile people needed to stay in France to one, maintain French culture and science, and two, resist.

Kelly: Tell us about the Resistance and what role Joliot had in that.

Weart: This, of course, is hard to know about because they didn't keep any records. But there isn't any doubt that Joliot gradually became one of the leaders of the Resistance. He was a very prestigious person, so that he was able to command a certain respect among people. The Resistance in France was not at first organized at all, and it was underground. Joliot went back to the Collège de France. He set up new scientific work. He got to work on his cyclotron.

The Germans gave him a person by the name of [Wolfgang] Gentner, who had worked with Joliot at the Radium Institute some years earlier and was friendly to him. One doesn't know whether Gentner deliberately covered up—helped Joliot cover up his activities, or whether Gentner didn't know about them.

But as things progressed and the Resistance became more organized, Joliot began to do Resistance activities. We don't know much of what they were, but we know that he did help mobilize people. Radios were made for the Resistance in the Collège de France under the Germans’ noses.

Only in the few last weeks of the war, Joliot had to go underground. We are not quite sure why, but he had to go and live incognito just towards the very end, before the Germans left. He could very easily have been betrayed by somebody, taken, tortured, and killed. This is what happens to leading people when they were found.

At some point during this, he joined the Communist Party. The Communist Party had already been underground before the Germans arrived, so it was the best place to organize the resistance. Also, they had established a reputation during the late ‘30s of being progressive for the working people, particularly the belief in sciences. The route to progress was pure Marxist philosophy. Unlike the socialists in the Popular Front government, they had supported the resistance to fascism in Spain. All of these things made the Communist Party quite popular and acceptable among French intellectuals. It was quite natural for Joliot to join the party as part of his Resistance activities.

Kelly: Ironically, the Americans at least suspected that Joliot might be a collaborator with the Nazis.

Weart: Well, because there he was in his lab, running a cyclotron and so forth, and promising all kinds of great nuclear discoveries would come out of his cyclotron. Of course, nothing ever came of it.

But they managed to keep their funding and keep people out of the Army, which was an important thing in France in those days, to keep young men from being—not out of the Army, keep them from being deported to work on farms and factories in Germany, which was what happened to young men. They managed to keep some young men out of that. As you said, keep French science alive. Also, unknown to the Germans, help out with the Resistance.

Kelly: In your book, you talk about how Joliot was kind of clearly in charge of his lab. He told Gentner, or the Germans who had come to work at the lab, to take advantage of the equipment that he had, that they couldn't remove the equipment and that they couldn't work on anything that related to weapons.

Weart: The Germans wanted Vichy France to be an ally, or at least not to be an enemy. They cultivated cultural relations with the French. Prominent Germans went to give lectures in France. They wanted to show that there were people in the French elite who could cooperate and collaborate with the Nazis. Joliot's lab was set up as one of those examples, as a place that showed that Germans and French could get along together.    

They allowed Joliot to stay in charge. They didn't try to pack up the cyclotron back to Germany. It was probably much better to leave it running where it was. Germans would come and work with the French, and everybody would be great friends. That was the set up. To the Germans, it was a nice propaganda thing. To Joliot, it was a façade that allowed him to do what he wanted to do in the interest of France.

The Americans were suspicious of Joliot from the start. But that was probably mainly when they found out that he was a communist, because to most Americans being a communist was a lot worse than being a fascist, unfortunately. 

Kelly: We left off at Bordeaux with the ship sailing, and Kowarski and Halban on board. So what happened next?

Weart: This is another saga. So Halban and Kowarski went to Britain. The British were pioneers in the race for the atomic bomb. They were the ones who would have a bomb dropped on them first, if the Germans got it. They could see themselves in a race with the Germans. It was also in Britain that it was first recognized how to make an atomic bomb, that you didn't need many tons—as everybody had thought—but that all you needed was pounds. This was the discovery of Frisch and [Rudolf] Peierls conveyed to the British government. In fact, the Germans and the Japanese never did figure it out. The Americans only learned about it from the British.

The British were hell-bent on working towards—the first people to recognize an atomic bomb was feasible, and feasible in time to affect the war. They would take any help they could get. They set up Halban and Kowarski with their heavy water to start doing more of the same kind of research that they had been doing.

Halban, as conceiving himself as the senior person and Kowarski as his worker, Halban conceiving himself as Joliot's representative and therefore the representative of French science, tried to insert himself as the representative of France in all of these deliberations and negotiations which developed between Britain and the United States.

There was a period of cooperation in which the British gave the United States everything they could including not only ideas about nuclear energy, but most importantly radar and all of these other things. Then it gradually developed into a period in which the United States tried to take as much as they could from Britain and keep it for themselves, and not let the British share in the benefits of it. This was the way things developed. Halban and Kowarski were brought over eventually to Canada as being a much safer place to work than in Britain.

Another person who had been in close contact with Joliot, Bertrand Goldschmidt, who also escaped from France and wound up in a Manhattan Project laboratory in Chicago, where they needed radiochemists—which was people expert in the chemistry of radioactive substances, which Goldschmidt was. He worked on the Manhattan Project.

These Frenchmen were scattered about, not entirely trusted by the Americans because they were French, and they even knew communists or at least had friends who were communists. The British set them up in Canada as a way to maintain at least some independence from the Manhattan Project.

Information necessarily leaked both ways. The Manhattan Project was set up by General [Leslie] Groves to try to keep everybody compartmentalized. The scientists quickly understood that if you compartmentalized everything, nobody would learn anything from anybody else and they would never get anything done whatsoever. They were perfectly free in passing information back and forth. This included back and forth with the British team—I would probably call it the Franco-British-Canadian team that was set up in Canada.

Their setup was to produce a nuclear reactor, if you will, in order to maintain their independence from the American Manhattan Project with a view towards postwar applications—both civilian, nuclear reactors, nuclear energy, and eventually in the nuclear weapons. This was the British entry. This was the British horse in the race towards postwar nuclear energy was the team set up in Canada.

Kelly: What kind of reactors were they building?

Weart: You know Kowarski was there when there is a nice acronym. ZEEP was the Canadian heavy water reactor, which was built with a lot of work by the British, some help from the American information.

The point is that they set up a reactor, got it working, developed teamwork, expertise, connections with industry and the military, and then were brought back to England and ultimately, became the seed of the British nuclear energy program. The roots of all reactors in Great Britain and all the reactors that they built elsewhere in the rest of the world, the roots of Great Britain's nuclear deterrent, which is one of the world's major powers. All of those go back to Canada and the Franco-British team in Canada.

Kelly: There was some problem with the Canadian operations in that Groves was very upset with Halban and his close relationship with Joliot and a trip that he took.

Weart: I don't remember the details of that. The general rule here is that Groves was suspicious of any foreign scientist, and particularly those that wanted to meddle in what he considered the Americans’ interests through trying to get patents and making their own independent relationships with industry.

He was particularly concerned, as was Halban, with the power of patents, which of course was not the case. Governments do what they want to do, and don't pay any attention to legal patents. But there was a lot of money involved. and Groves didn't want anybody else outside the United States to get that.

Then of course, there was the further problem that, you know, foreigners are very likely to be communists, too. Groves very early on recognized that the Soviet Union represented a major threat, and that Soviet spying in particular represented a major threat. He was very worried about it before there was even any evidence of it. Then of course, as it turned out, he was absolutely right.

This was a very natural thing, to suspect people who were not American citizens. Halban and Kowarski weren't even Frenchmen. “God knows, where they were from,” that kind of a thing, and, “Jews or half-Jews in addition.” Not a good thing in those days to be half-Jews, which both Halban and Kowarski were.

Kelly: What happened after the war? Where did these refugees go?

Weart: After the war, Joliot gathered them all back, except Halban. Kowarski told me that everybody refused to go back to Joliot if Halban came. I thought, “Well this is Kowarski. He chafed working under Halban, and didn't get on with him”. That's the problem with oral history. You don't trust memories.

But I asked every other person and every other person confirmed, "Yes, we would not go back to work with Joliot if Halban came with us." It shows that oral history sometimes can be valuable if you get enough people to confirm it.

Halban, he had just become abrasive and aggressive and tried to take control of everything. As I say, he conceived himself as a representative of France. Between his German background and wealthy background and his sense of superiority, he simply grated on everybody. They decided they could get along fine without him. The British gave him a job and he got on fine in Britain, but the rest of them came back to work with Joliot.

Joliot was now not only a great Nobel Prize winner and the heir to the Curies’ fame, but also a war hero for his work in the Resistance. Recognized as being connected with the most amazing thing ever in human history, the atomic bomb. He was able to get himself set up—with the help of Dautry and others—an atomic energy commission, the CEA, the Commissariat for Atomic Energy, whose mission was to produce nuclear reactors and get France into the nuclear energy business.

Kowarski built their first reactor, ZOE, a nice acronym. Kowarski showed his administrative powers there, with the help of a lot of information he had brought back from Canada, some of which came from the United States ultimately and some of which he had developed himself. Goldschmidt was there and Francis Perrin, whom we haven't mentioned, a theorist, and a number of other people.

Set to work in the complete chaos and misery of postwar France to set up a new source of energy. It didn't hurt that France was absolutely devastated. The power went off all the time, if you could even get power. They were short on coal. People were literally freezing in the dark. Getting a new source of energy was certainly a good idea for postwar France. Also, France didn't have any oil.

Kelly: How did this play out? From the first plant, which was after the war—let's see, probably in the ‘40s, late ‘40s.

Weart: Yeah, set up in '46 and proceeded in what we would recognize as a standard route. You build an experimental reactor, a very low power reactor, so everybody learns how to do it. Then you go and you acquire uranium. It turns out uranium is everywhere, if you want it badly enough. You can find a source of very low-grade uranium.  People went around France with Geiger counters, finding bits and pieces of it.

You cooperate with people abroad, who are doing the same things. You build up a nuclear industry. At a certain point, it becomes an engineering and an administrative problem, which of course Joliot was very good at. Along the side, you do your research and so on. It becomes a question at this point of industrial development. 

The hitch, of course, was that if you build a reactor, then you are building a way to get an atomic bomb. The French, needless to say were very well aware of this. But as we have seen with many other countries since, you can go a long way saying, "Oh, oh, all we want to do is do peaceful nuclear energy." Then ten years later, you say, "Oh, look, look, we have all of this stuff around. We can make a bomb with it." That was basically the route that the French had.

Joliot would have none of it. He believed that there were enough weapons in the world. He believed that science should be used only for peace. Of course, at this point, he was a communist.

He had joined the Communist Party simply as part of being part of the patriotic anti-fascist resistance, but the Communist Party—as many people recognized at the time, but many people have not recognized—was what we now call a closed information system. You believed what the Party people said and what the Party newspapers and so forth said. Anything anybody else said was “fake news.” The ideas of the gulag, of the mass starvation, of the show trials, all that was fake news. In fact, the Communist Party were the good guys and doing good things.

The communist members were supposed to get together once a week with other Communist Party members, kind of to reinforce one another and to quash any heretical ideas that the party members might have. It was almost like a cult. Joliot was caught up in this. Eventually all your close friends and people you communicate with are communists. He became caught up, pretty much, in the communist world.

The [French] Atomic Energy Commission naturally had quite a few communist people in it. This was not so unusual in France after the war. The Communist Party was a major political party. Many, many Frenchmen were communists. They were accepted by a lot of the intellectuals. People like [Jean-Paul] Sartre and so forth were famously sympathetic with the communists, for much longer than they should have been. It was not unnatural for there to be lots of engineers and scientists and so forth who went into the Atomic Energy Commission, just as they would go anywhere else. But it was also a friendly place for them.

I was actually able to find out roughly how many there were there, because a Communist Party cell is supposed to split when it reaches a certain level of membership, I think thirty or whatever. At one point, I found birthday congratulations, I think it was to Joliot, from the members of the two communist cells within the CEA. Then a year later, from the three communist cells within the CEA. It gives you a feeling for a fair number. A lot more than you would have found in the railroads, but then this was an engineering and scientific and very progressive thing. But from the viewpoint of the anti-communists, it was riddled with “Reds.” It was a very suspicious organization.

Joliot, being a very prestigious person and also a communist, was exploited by the communists to become a leader in the world movement for disarmament, the anti-nuclear weapons movement, very big. Millions of Frenchmen signed petitions. Hundreds of millions of people around the world signed petitions for the abandonment of nuclear weapons—which of course was all in the interests of the Soviet Union. If the United States promised to abandon its nuclear weapons, and maybe they would if the Soviet Union promised to abandon its nuclear weapons. Everybody knew they would put them in tunnels or whatever—except Joliot, who was politically one would say pretty naïve. He fell in with the communists. He made speeches. He sincerely believed in disarmament and world peace.

When he finally definitively said that he would not participate in anything in the Atomic Energy Commissariat that would contribute to building nuclear weapons, he was fired. Not unsurprising. This was 1950. The Cold War had begun. The United States didn't even have to pressure France. There is no sign that they pressured France. The French had plenty of reasons on their own at that point, with anti-communism on the rise, to get somebody else in charge of their Atomic Energy Commission and root out the communists who were in there, find out the ones who were the most dedicated and get rid of them.

The Atomic Energy Commissariat continued to work towards peaceful nuclear developments, reactors and so forth. They had no particular need to do any more because until you have a lot of reactors, you don't need to worry about it [building nuclear weapons]. Then when [President Charles] de Gaulle came in, they said, "Okay, it's time to actually build them." So they started building them.

Kelly: What year was that, '58?

Weart: I forget, '58, '60, something like that, when they explicitly started working on, “How do we actually build one?” Surely, France would have tried to do something. The countries that didn't, like Germany and Italy and Japan, had been the losers in the war. France had been a half loser in the war. It was kind of touch and go whether it would join with the real losers and not even try to make a bid for nuclear energy, or whether it would go with Britain and the Soviet Union and the United States and try to build up a full nuclear industry.  

It is largely because of Marie Curie and the legacy of Marie Curie through the Radium Institute and Joliot and so forth and ultimately the Atomic Energy Commissariat that France became the country with the most nuclear reactors, the only country that gets 70 percent of its energy from nuclear energy, electrical energy, and has the classic triad of nuclear submarines and missiles and airplanes. It maintains itself, in this sense, on full equality with the other nations.

Kelly: The spies that were in Montreal, Alan—

Weart: Nunn May, yeah.

Kelly: Yeah, in '46 he passed Montreal Lab secrets to the Soviet embassy in Canada.

Weart: Yeah, this was one of the great shocks. The whole Canadian thing came under disrepute when it was found that Alan Nunn May, one of the British workers there, had been one of these nice, fine upper-class British class people who believed in communism and passed secrets from the Montreal nuclear program onto the Soviets. His secrets, as it turned out, were much less important than ones that were being leaked from all over the United States, the Manhattan Project.

But it was one of the first cases that came out into the open. It was one of the things that led to increased hunting for spies, suspicion of foreigners, and in particular, worries about what was going on with those French and British up in Canada. It tended to accelerate the process of the United States excluding everybody who wasn't American from any kind of cooperation in nuclear affairs.

Kelly: Maybe you want to talk about that issue, how it played out, especially with the   legislation Congress passed to keep atomic energy kind of to Americans and not share.

Weart: This was not so much a problem for the French, because they couldn't have much hope of cooperating with the Americans. But they could hope to cooperate with the British, their long history of Franco-British cooperation.

The British had strong hopes of cooperating with the Americans. Churchill and Roosevelt had agreed there would be full cooperation. The British were the ones who kicked the Americans until they started working on nuclear energies. The British had high hopes that the cooperation that was established during the war with all of the top British and even Niels Bohr, who had immigrated to Britain, escaped to Britain, and all of these other people going to Los Alamos to help build the atomic bomb.

How long the United States would have maintained this once they no longer needed the British is hard to say, but certainly, as they began to find more and more signs that there were British communists who were leaking things, increased their desire to have nothing more to do with it, to cut them off. “We can do it on our own. We can beat them.”

Not only a matter of military security, they hoped of course to delay other countries getting the nuclear weapons, they didn't want the British to get it or anybody else in the world to get them. But also it was widely believed that there were enormous commercial possibilities for nuclear reactors, that nuclear energy was going to take over the entire world economy in the next twenty years and so forth. Electronics was old hat, nucleonics was the new thing, and so on.

It was also for standard capitalist commercial reasons and national advances that they wanted everybody else out so that they could dominate. After all, this was the late 1940s. The United States was producing half the industrial output of the entire world, since most of the rest of the industrial output was in rubble. It was a normal thing for the Americans to say, “We will go it alone and we don't need cooperate with anybody else. We will just cut you off.”

Kelly: Maybe we should take on some of your larger themes of the scientists in power. That's the name of your book. Is this a double entendre?

Weart: Yes, Scientists in Power. When it came out in the French edition, it was impossible. You can't say “Les savants au pouvoir,” it sounds like a rallying cry or whatever. They never did come up with a good French translation for my title.

Now I am talking about myself as a historian. I found that other people have appreciated my book, Scientists in Power, because it attempts a whole history. Within the course of two pages, you can go from the details of an experiment to people trading patents with industry, to talking with the military people. Then back down into the lab again, to what people are doing on the lab bench, to try to see all the forces that are working simultaneously.

It's a unique story. It's a particularly good story for a historian because nuclear fission was so new that you can actually—if a person tries to understand what you are saying, you actually can explain it to them, which you can't do with most physics developments. But fission, you can actually explain what was happening in the lab. To the extent you can penetrate it, you can explain what was happening in the government and industries.

The major theme of my book—this is a little harder to translate. The book starts with, “Les cerveaux sont fâcheusement pourvus d’estomacs” [from Jean Perrin]. “Brains, unfortunately enough, are attached to stomachs.” That's the main theme that I tried to address is, how do these scientists find support? What makes it possible for them? What they really want to do is to discover knowledge. That's their main thing. They don't want to live in poverty. They want to live comfortable upper-middle class cultured lives.

But as long as they have that, what they really want to do—they don't want to go out and shove people around. They want to do scientific knowledge, but that doesn't mean they don't want to change the world. They do want to change the world. It's their belief that by developing scientific knowledge and, past that technology and engineering, they will change the world. They are convinced this will be for the better. There has been some doubt about whether knowing more makes you better off, but at least it gives you more choices.

This is what they wanted to do. This is what they did do, although half of their work had to be done in a laboratory bench. But going around to ministries saying, “We need some more funding for the young scientists,” going to industrialists, saying, "If you give us this uranium, we will be able to discover things. Then you will be able to make more money out of it."

Going to the public and arguing that, “We need this kind of a political system in order to support science.” They did care about the plight of the worker and all of that kind of thing. But their main concern was that they had a political system that would support science because over the long run. This is what was most important to them, and what they believed—not without justification—was the best thing that they could do with their lives to improve the world prospects for future civilization.

This goes back to the late nineteenth century. Well, it goes back to the Enlightenment, but it was particularly a future of the Third Republic. Marie Curie and her friends, Jean Perrin in particular, a very noted physicist who made it one of his life goals to get in with the politicians. As I said, they all went to the École Normale together, they knew one another. It was a small circle. To promote the scientific world view and the development of science by raising funds for it.

It goes back to the Dreyfus Affair when France split in half, half of them being allied with the clerical side and even monarchists, and the other half being on the progressive side. By no means communists then or even socialists, but just good liberals, internationalists looking towards good international relations. The Curies and their people were entirely on that side.

It was a fairly small social circle. The top levels in French intellectual circles were small. They knew artists. You go into one of these people's apartments and probably fine some good works of art, which they might have done themselves, because everybody was very cultured. They did their literature. They could write fluently. This was a particular circle at a particular time, during the heyday of the Third Republic from, let's say, the 1890s to the 1920s. This is not just Joliot. It's this entire circle that set themselves to advance French science and thereby to advance world science and thereby to advance civilization.

Kelly: Talking about the circle, could you talk a little bit about the Langevin family and the relationship with the Curie family?

Weart: Langevin, as I have already said, Langevin was extremely important in promoting Joliot's career at several places. They went way back, because Langevin was a significant figure before the war. He was a good friend of the Curies and Jean Perrin and all of these other people. Sometime after Pierre died, he became Marie's lover for a short period, which unfortunately became exposed and led to a terrible scandal. They broke apart and after that, simply remained friends.

He was one of those people. He was a bit more progressive, as we would say, and actually was one of the first to join the communists. He became a communist already during the Popular Front days, for which the Nazis tried to gather him in during the war. But he was such a popular senior figure that they eventually had to release him.

Of course, in August everybody in France goes on vacances, and where do you go? Well, in some cases, you go to Brittany.

Langevin and Jean Perrin and some others had found this little town, L'Arcouest, charming town, like all of them are, and bought some summer places there. Eventually the Curies and others joined them. This was their little summer circle, or the circle during the vacances where the children would go and play in the water and that sort of a thing.

Again, it was an example of the social cohesion that this circle had during this heyday of the Third Republic. Not only were they in Paris literally all within walking distance of one another, but even on their vacances, they were basically within walking distance of one another and could carry on their friendly social relations and intellectual discussions and raising their children, to a certain extent, together, all of that kind  of thing.

Not possible now. The number of scientists, the number of intellectuals, the number of everything has increased so explosively, that it is no longer possible for all the top scientists—let alone all the top scientists, politicians, artists, and intellectuals—to know one another intimately. Now, not even all the top physicists recognize one another's names.

There were how many people were graduates of the École Normale or the École Polytechnique? They didn't have to pay attention to hardly anybody else. It was quite unusual for Joliot to come to be neither a Normalien nor a Polytechnicien and still reach the very top circles. It would not have been possible without A, his own brilliance, both scientifically and his personality, and B, the openness of the Curie circle to outsiders, be they from Poland or Russia, be they Jews or God forbid, even not from the Normale or the Polytechnique.

Kelly: Perhaps that is somewhat of a reflection of the fact that Marie herself— 

Weart: Oh yes, it all goes back to Marie Curie and her decision to leave her native country. 

Kelly: Tell us about that decision. Was it easy for her?

Weart: I don't know about that decision in particular. If she wanted to be a scientist and she did, there was no way to be that in Poland, even for a man. Because of the Russian occupation, it would have been very difficult. For a woman, no matter how brilliant, no matter how determined, the only route from Poland to any kind of career was through Paris. She was only one of many Eastern Europeans who went to Paris in those years. Kowarski being another, of course. 

Kelly: To what extent was Marie when she got to France confronting barriers because she was a woman?

Weart: She was one of the very few women who managed to push her way into the French scientific establishment. She did it partly because she was willing to put up with the living in the garret and the hard life.

If she hadn't fallen in love with Pierre and he hadn't fallen in love with her, I don't know whether she could have succeeded. That certainly gave her a leg up in the whole process. She was being supported before that. Jean Perrin, Becquerel, and other leading people recognized her as someone who should be supported. But whether she could have gotten the support that was necessary for the radium work, I don't know. Of course, she needed Pierre's instruments also. So it's a collaboration.

Kelly: We left Irene off a bit after her Nobel Prize, and then Joliot stepped up to his administrative duties and his running—

Weart: Oh, I did cover that. She discovered nuclear fission, but didn't know it. After the war, she continued her radioactivity research.

What's probably worth saying about Irene and about these things in general—again, she was a woman scientist and she supported women scientists, as Marie Curie did. There were two unusual characteristics of the Radium Institute and also of Irene's work. One was a lot of people from Eastern Europe, and the other was a lot of women. Marie primarily, but also Irene to a certain extent, became a role model for women scientists.

When I was doing research on this, I would go into many labs in France. If it was a woman's lab, you might very well find a picture of Marie Curie up on the wall. It almost became excessive, you know. The French would say, "Aren't there any other women scientists? Enough with Marie Curie. Let's remember, there were lots of other women scientists.”

But there was no question that in France in particular, but also worldwide, that Marie Curie inspired many women to go into scientific fields who otherwise would not have done so. To the extent that they were able to, they not only inspired them, but they also found money for them, money, and jobs.

Kelly: That's very interesting. 

Weart: I imagine to this day—I don't know, but I'll bet if you walk into the Radium Institute, you would find a higher fraction of women there than you would in other nuclear labs.

Well, I think it's worth saying another word about Dautry, because this, again, is the French thing now. Now, here we have the Polytechnicien side of it, the engineering side, the close connections with the military and the government. Later on, he became one of the leaders of the SNCF, a very successful French railroad system.

The reason France has been so successful with its nuclear reactors goes back to Joliot and all of those, but it also goes back to the idea of a close collaboration with a fairly small circle of elite, well trained, well educated, cooperative people in industry and government all working together. Of course, France is notoriously dirigiste.

The United States people tried to—every company wanted to build its own type of nuclear reactor. The result was huge cost overruns and problems of safety and so forth. France organized itself much better. The United States had the right idea when they got [Admiral Hyman] Rickover, the guy from the Navy, to run their nuclear Navy program, but the French were smarter still. They basically turned the whole program over to the Navy officers. On submarines, nothing can go wrong. It's exactly the right spirit that you want to have in your nuclear reactor program. 

There is something about the way that the French organized their society at that time. I am not saying now, but the way the French society was organized during the late Third and the Fourth Republic that made it particularly able to build up a reliable, safe, economical nuclear energy system, which I hope can still be a model for the world because—to turn to my other main historical interests—climate change is going to sink civilization, unless we can change things very rapidly.

We don't need A, B, or C. We need all of the above. We need nuclear reactors like France have. Without those and without many other things, without solar, without wind, without conservation, without twenty other things I could name, but also including nuclear reactors. Without them, we are sunk. I very much hope that the French will continue to inspire people by their success in this area.