One of the biggest misconceptions that people have about the Manhattan Project is that prior to Hiroshima, all knowledge of atomic energy and nuclear fission was secret — that the very idea of nuclear weapons was unthought except inside classified circles. This is a side-effect of the narratives we tell about Manhattan Project secrecy, which emphasize how extreme and successful these restrictions on information were. The reality is, as always, more complicated, and more interesting. Fission had been discovered in 1939, chain reactions were talked about publicly a few months later, and by the early 1940s the subject of atomic power and atomic bombs had become a staple of science journalists and science fiction authors.
John W. Campbell, Jr., was a prolific editor and publisher of science fiction throughout the mid-20th century. In the annals of nuclear weapons history, he is best known for publishing Cleve Cartmill's story "Deadline" in March 1944, which talks about forming an atomic bomb from U-235. This got Cartmill and Campbell visitors from the FBI, trying to figure out whether they had access to classified information. They found nothing compromising (and, indeed, if you read Cartmill's story, you can see that while it gets — as did many — that you can make atomic bombs from separated U-235, it doesn't really have much truth in the specifics), but told Campbell to stop talking about atomic bombs.
But Campbell's flirtation with the subject goes a bit deeper than that. Gene Dannen, who runs the wonderful Leo Szilard Online website, recently sent me a rare article from his personal collection. In July 1941, Campbell authored an article in PIC magazine with the provocative title, "Is Death Dust America's Secret Weapon?" It's a story about radiological warfare in what appears to be rather middle-brow publication about entertainment. Click here to download the PDF. I don't know anything about PIC, and haven't been able to find much on it, but from the cover one wouldn't necessarily expect it to be a source for people looking for hard-hitting science reporting — though the juxtaposition of DEATH DUST, "world's strangest child," and the "DAY DREAM" woman is a wonderfully American tableau.
The story itself starts off with what has even by then become a clichéd way of talking about atomic energy ("A lump of U-235 the size of an ordinary pack of cigarettes would supply power enough to run the greatest bomb in the world three continuous years of unceasing flight"), other than the fact that it is one of the many publications that points out that after an exciting few years of talk about fission, by 1941 the scientists of the United States had clamped themselves up on the topic. The article itself admits none of this is really a secret, though — that all nations were interested in atomic energy to some degree. It vacillates between talking about using U-235 as a power source and using it to convert innocuous chemicals into radioactive ones.
Which is itself interesting — it doesn't seem to be talking about fission products here, but "synthetic radium powders." It's a dirty bomb, but probably not that potent of one. Still, pretty exciting copy for 1941. (Campbell would much later write a book about the history of atomic energy, The Atomic Story, where he also spent a lot of time talking about "death dust.")
The article contains a really wonderful, lurid illustration of what a city that had been sprayed with "horrible 'death dust'" would look like:
The most interesting parts of the article are when it veers into speculation about what the United States might be doing:
With all the world seeking frantically for the secret of that irresistible weapon, what are America's chances in the race?
It is a question of men and brains and equipment. Thanks to Hitler's belief that those who don't agree with him must be wrong, America now has nearly all the first-rank theoretical physicists of the world. Mussolini's helped us somewhat, too, by exiling his best scientists. Niels Bohr, father of modern atomic theory, is at Princeton, along with Albert Einstein and others of Europe's greatest.
The National Defense Research Committee is actively and vigorously supporting the research in atomic physics that seeks the final secrets of atomic power. Actively, because the world situation means that they must, yet reluctantly because they know better than anyone else can the full and frightful consequences of success. Dr. Vannevar Bush, Chairman of the Committee, has said: "I hope they never succeed in tapping atomic power. It will be a hell of a thing for civilization."
Bohr was in fact still in occupied Denmark in July 1941 — he had his famous meeting with Heisenberg in September 1941 and wouldn't be spirited out of the country until 1943. The photographs identify Harold Urey and Ernest Lawrence as American scientists who were trying to harness the power of atomic energy. Since Urey and Lawrence were, in fact, trying to do that, and since Vannevar Bush was, in fact, ostensibly in charge of the Uranium Committee work at this point, this superficially looks rather suggestive.
But I think it's just a good guess. Urey had worked on isotope separation years before fission was discovered (he got his Nobel Prize in 1934 for learning how to separate deuterium from regular hydrogen), so if you know that isotope separation is an issue, he's your man. Lawrence was by that point known worldwide for his "atom smashing" particle accelerators, and had snagged the 1939 Nobel Prize for the work done at his Radiation Laboratory. If you were going to pick two scientists to be involved with nuclear weapons, those are the two you'd pick. As for Bush — he coordinated all of the nation's scientific defense programs. So of course, if the US was working on atomic energy as part of their defense research, Bush would have to be in charge of it.
The other illustrations seem to be just generically chosen. They are particle accelerators of various sorts; one cyclotron and many electrostatic (e.g. Van De Graff) accelerators. Cyclotrons did have relevance to isotope separation — they were used to develop the Calutrons used at Y-12 — but the captions don't indicate that this is why these machines are featured.
I've never seen any evidence that Campbell's story in PIC came to any kind of official attention. Why not? In the summer of 1941, there was a lot of talk about U-235 and atomic energy — and Campbell's article really isn't the most provocative of the bunch. There wasn't any official press secrecy of any form on the topic yet. "Voluntary censorship" of atomic energy issues, which is what would get Cartmill and Campbell in trouble later, didn't start up until early 1943. Mid-1941 was still a time when a journalist could speculate wildly on these topics and not get visits from the FBI.
The irony is, there were official fears of a German dirty bomb, but they didn't really crop up until 1942. But the American bomb effort was starting to get rolling in the late summer of 1941. By the end of 1941, Bush would be a convert to the idea of making the bomb and would start trying to accelerate the program greatly. It wasn't the Manhattan Project, yet, but it was on its way. Campbell's article was, in this sense, a bit ahead of its time.
What I find most interesting about Campbell's article is that it reveals what the informed, amateur view of atomic energy was like in this early period. Some aspects of it are completely dead-on — that U-235 is the important isotope, that isotope separation is going to matter, that places with particle accelerators are going to play a role, that the acquisition of uranium ore was about to get important, that fears of German use of atomic energy existed. But parts of it are completely wrong — not only would dirty bombs not play a role, he doesn't seem to understand that fission products, not irradiated substances, would play the strongest role. He doesn't really seem to understand how nuclear power would be harnessed in a reactor. He doesn't really seem to get fission bombs at all.
This mixture of accuracy and confusion, of guess and folly, tells us a lot about the state of public knowledge at the time. Atomic energy was a topic, it was an idea — but it wasn't yet something tangible, a reality. So when people found out, in 1945, that the United States had made and detonated atomic fission bombs, they were primed to understand this as the beginning of a "new era," as the realization of something they had been talking about for a long time — even if the details had been secret.