"Yes. That's how they got in."
"I see. Then go ahead. No, Sergeant Foster, you stay because you may have to do something about this and it is best that you get your story first hand. It'll save time. Now, Mr. Bronson?"
"Well, under the combined forces of the magnetic field and the electronic bombardment the phosphor vibrated. I half recognized the vibration. It was like a very faint whisper in another room that you can't quite understand—but you know that someone is whispering.
"So I went to work on the phosphor and used a contact microphone on it, and got in touch with some woman, who gave her address as across the street from my home. When I went over there, I discovered that it couldn't possibly be correct. Later I refined the thing a bit and learned that her name was Carlson. Then I built a means of talking back to her, and I learned that she was not on this world at all. It was—"
"Not on this earth—but talking American?" demanded Norris.
"Yes."
"Do go on," said Captain Norris, putting down his pipe and leaning forward a bit.
"Well, you see, Captain Norris, there were some of the Manhattan Project physicists who believed that there was a chance that the atomic explosion might be strong enough to start a fission train in the earth itself. In other words, they were afraid of setting the earth on fire atomically. This was a possibility, and it seems that we now have two worlds, each following the natural chain of events pursuant to the two different possibilities."
"Very interesting, Mr. Bronson. Please go on. There must be more."
"After learning this, we decided to do what we could to alleviate the difficulty. I went to bed. In the night—or rather while I was asleep, they used some means or other to pass through from one world to the other and one of them clipped me and taped me up. He told me that they were going to move in on us—to displace us. I escaped and came here. Something must be done!"