“And all this just came from nowhere?”

“It just happened,” he says, shrugging.

Richard worked in a factory for four years, but his disorder meant he spent most of his time in his flat. His love of chemistry continued undimmed, but the possibility of him becoming a pharmacist had practically gone. So, instead, he decided one day to start a collection: He would scour the Internet and buy an ampoule of every chemical element. He quickly realized he had to downgrade his ambition. “There are some very unstable radioactive elements, like polonium and francium, that last just a couple of minutes and then decay. They’re impossible to get.”

But he persevered with the others.

“Do you have any of them still here?” I ask.

“Sure,” he says. “Would you like to see them?”

He disappears into his bedroom and returns holding a basket filled with ampoules of gold and silver and platinum and thallium and beryllium. Some are solid blocks, some glittering shards, others shining slivers. The basket looks like a treasure chest.

“This is the most amazing one,” Richard says, picking up an ampoule marked “Cesium.” It looks like solid gold. “Watch,” he says. “If you warm it up . . .”

He closes his fist around it for thirty seconds. Then he shows it to me again. It has melted. We both look at it, amazed, as if we’ve just witnessed a magic trick.

“And then,” Richard says, “I began to collect radioactive elements like radium and uranium and americium.”

Richard was Googling “americium” one day when he found a story, in Harper’s magazine, about a Michigan boy named David Hahn who grew up in the 1990s. Both boys spent their childhoods blowing things up in the garden. Hahn once turned up at a Boy Scouts meeting with a bright orange face due to an accidental overdose of canthaxanthin. Hahn also got expelled from camp for dismantling a smoke detector (he was trying to extract the americium—pretty much everything you need to split the atom you can find on eBay or in smoke detectors and antique luminous-dial clocks).

Those were the days before the Internet, so getting hold of information about how to build a nuclear reactor was more complicated for Hahn than it would turn out to be for Richard. He learned how to do it by writing to the U.S. Nuclear Regulatory Commission and pretending to be a physics teacher. Did they have any pamphlets on how to split the atom?

“Nothing produces neutrons as well as beryllium, Professor Hahn,” they wrote back.

And that’s how David Hahn managed to turn his potting shed into a nuclear reactor.

It wasn’t long before the Michigan police cottoned on, and in June 1995, eleven men in protective suits descended on the dangerously irradiated shed. He was shut down.

Sixteen years later, in Ängelholm, Richard read the Hahn story and felt inspired to try it out himself. This is how Richard went about trying to split the atom. First, he got a saucepan. Into it he put his radioactive elements—the americium and radium. He mixed them up with sulfuric acid and beryllium and turned on the stove. The mixture bubbled up crazily, splashing all over the cooker and the floor. He quickly turned off the gas and posted a picture of the carnage on his blog, with the caption “The Meltdown!”

His plan, he says, was to repeat the experiment, but this time to collect into a test tube the neutrons that were emanating from the concoction. Then he’d have fired the “neutron ray” at a chunk of uranium sealed in a glass marble.

“What does the neutron ray look like?” I ask.

“It doesn’t look like anything,” Richard says. “You can’t see it.”

“How do you know it’s there?”

“You have to measure it with a Geiger counter,” he says.

“So what you’re saying is, you’d point the test tube filled with neutrons at the uranium marble, and that’s what would split the atom?”

“Yes,” Richard says.

Richard never did collect the neutrons into a test tube. After the meltdown, he decided to e-mail the Swedish Radiation Safety Authority to double-check that what he was doing was aboveboard.

“Hello!” read his e-mail of July 18, 2011. “I’m very interested in nuclear physics and radiation. I have planned a project to build a primitive nuclear reactor. Now I’m wondering if I’m violating any laws doing so?”

They e-mailed him back on August 11: “Hi. The short answer to your question is that if you build a nuclear reactor without permission, you are violating strict laws. It is a criminal offense and can lead to fines or imprisonment for up to two years.”

Richard was surprised. “The amount I had was very small,” he says, “so far away from the amount needed to make a dirty bomb or something like that. To get it to explode, you must have something called a critical mass, which is fifty kilograms of radium or six kilograms of plutonium. I had five grams. The worst that could have happened was I might have got radiation in me.”

“And got cancer years later?” I ask.

He shrugs. “Yes.”

Even though it took the radiation authority three weeks to respond to Richard’s e-mail, everything moved very quickly after that. Within days, they’d turned up at his flat with the police.

“They told me to get out with my hands up. They scanned me with Geiger counters. There was nothing. They measured the whole apartment. They said I was arrested for a crime against the radiation-safety law.”

And that’s it, so far. Sixteen weeks have passed and nothing has happened to him, besides making headlines all over the world.

“I don’t regret it,” he says, “because it was exciting. I’m sad I can’t do it anymore.”

We glance at his basket of elements. “There are no other experiments you could do with these?” I ask.

“I can,” he says, “but I don’t want to.”

“What could you do?” I ask.

“I could . . .” Richard pauses. “This thallium is very, very poisonous. If you break the ampoule, it would start to react with the air and oxidize. Thallium oxide. Very poisonous. If you get it on your fingers, you can die.”

“But you would never consider . . .”

“No, no,” Richard says. He pauses. “Actually, I’m thinking of trying again to become a pharmacist. I’m going to read up on some courses from the high school and begin to study in the university.”

•   •   •

I RECEIVE a slightly alarmed e-mail from Jason Bobe, who runs DIYbio.org, an online community for home-science experimenters. I’d e-mailed him as part of my research. He says he’s worried my story may discourage home science. Maybe, he suggests, I should talk to Victor Deeb, whose experiments in his basement went disastrously wrong in a very different way and whose story might offer a counterbalance.

Deeb lives in a small Massachusetts town called Marlborough. He’s retired, in his mid-seventies, and although he’s lived in the U.S. almost all his life, he still has a strong Syrian accent, which gets stronger as he becomes more incensed over the phone.

Three years ago, on August 5, 2008, a policeman happened to be driving past Deeb’s house. “He saw smoke billowing from the air conditioner in an upstairs room, so he called the fire department.” Deeb speaks in short, exact phrases, as if he considers our conversation to be like a chemical experiment, requiring complete precision.

A plug had shorted in the bedroom. The fire department put out the fire, glanced into the basement, and immediately called for emergency reinforcements.

“The whole fire department came,” Victor says. “The FBI. Even the CIA was here. It couldn’t have been any more crazy. They went into the sewer system to see if I was dumping anything down the toilet.”

What they had found in the basement was a hundred bottles of chemicals. None was hazardous. There was nothing poisonous. “I was working on a coating for the inside of beverage cans containing no bisphenol A,” Deeb says.

BPA, he explains, is standard in beverage-can coatings. The problem is that it can seep into the drink and play havoc with our hormones, causing men to grow breasts and girls as young as seven to have periods. Back in 2008, he says, “there were few references in the media to the negative effects of BPA. Currently, there is a deluge of articles. So my desire to eliminate BPA was ahead of its time.” He pauses. “I spent an enormous amount of time with the authorities, trying to explain what I was working on, but they had no perception. No concept.”