Manhattan Project Cyclotron Moved to City for Exhibition If physics has to do with the actions and reactions of something, then this is about physics. But really it is about a thing - a thing that was at the heart of breakthrough physics experiments that led to the crash program for the atom bomb in World War II. It is also about whether the movers could squeeze the thing through a door. It was a 16-feet-7-inch-long piece of the machine that scientists working on the Manhattan Project built to smash atoms. The door belonged to the New-York Historical Society on Central Park West. The historical society borrowed the device, a cyclotron, from the Smithsonian Institution, which has had it since 1965. The society is preparing an exhibition, "WWII & NYC," that is scheduled to open next month and offer a look at the city's contributions to the war. The cyclotron has been not been on public view since a display at the Smithsonian was taken down in 1977. That made it all the more desirable for the historical society, but it will not be the only unusual borrowed relic. Also in the exhibit is what Marci Reaven, the curator of the "WWII & NYC," described as the last vial of World War II-era penicillin. It was produced in a deep-fermentation tank in a factory in Brooklyn using a process that pushed lifesaving antibiotics from the laboratory toward mass production. The vial is tiny. The cyclotron is large, quite large, and when it arrived on Monday, there was a classic New York "how is the couch going to fit through the door" moment. Except that when you measured the couch in the showroom, no one was checking it with a Geiger counter to see if it was radioactive. "It was harmless," said Clare Richfield, a research associate who went to the Smithsonian's warehouse in Maryland months ago with a tape measure. I was climbing on it, taking measurements while they were doing the Geiger test. The problem for the movers hired to deliver the cyclotron was an arm that stuck out from one of the "dees," the semicircular chambers inside the wide, flat piece. Like the legs on a too-wide couch, the arm could not be removed. It made the job something of a challenge for Marshall J. Didier, who runs the moving company. Mr. Didier's crew specializes in transporting all-but-irreplaceable art and objects like King Tut's chariot, which they delivered to a museum in Midtown Manhattan in 2010. For the cyclotron, Mr. Didier made mock-ups that showed it could go through the doors at the society - the wide doors that open onto Central Park West as well as the newer glass doors just inside. Mr. Didier's crew rolled the cyclotron out of one truck and onto the long, flat bed of another. Then a cranelike machine picked up the cyclotron and lifted it over the steps at the front of the museum. That was when the couch problem presented itself. The cyclotron turned out to be a smidgen too wide to slide through the glass doors. Mr. Didier's crew pushed it through, but only after they had removed one of the doors. Ms. Reaven, who is also a vice president of the historical society, applauded as it rolled through - and sounded relieved. "Some objects have incredible power because of the stories they open up," she said. This is one of those objects. It was an important story for the war, and it's an important New York story. It reveals the concentration of talent here and the passionate engagement that people here had in the frightening events that were happening around the world. If that object hadn't told all of those stories, its size and its weight and the expense of bringing it up might have given us pause.