To put it bluntly, the substance we are studying did not originate in our Universe at all, but in another - an alternate Universe - a parallel Universe. Call it what you want.
"Once here - and I don't pretend to know how it got across - it was stable still and I suggest that this was because it carried the laws of its own Universe with it. The fact that it slowly became radioactive and then ever more radioactive may mean that the laws of our own Universe slowly soaked into its substance, if you know what I mean.
"I point out that at the same time that the plutonium-186 appeared, a sample of tungsten, made up of several stable isotopes, including tungsten-186, disappeared. It may have slipped over into the parallel Universe. After all, it is logical to suppose that it is simpler for an exchange of mass to take place than for a one-way transfer to do so. In the parallel Universe, tungsten-186 may be as anomalous as plutonium-186 is here. It may begin as a stable substance and slowly become increasingly radioactive. It may serve as an energy source there just as plutonium-186 would here."
The audience must have been listening with considerable astonishment for there is no record of interruption, at least until the sentence last recorded above, at which time Hallam seemed to have paused to catch his breath and perhaps to wonder at his own temerity.
Someone from the audience (presumably Antoine-Jerome Lapin, though the record is not clear) asked if Professor Hallam were suggesting that an intelligent agent in the para-Universe had deliberately made the exchange in order to obtain an energy source. The expression "para-Universe," inspired apparently as an abbreviation of "parallel-Universe," thus entered the language. This question contained the first recorded use of the expression.
There was a pause and then Hallam, more daring than ever, said - and this was the nub of the Great Insight - "Yes, I think so, and I think that the energy source cannot be made practical unless Universe and para-Universe work together, each at one half of a pump, pushing energy from them to us and from us to them, taking advantage of the difference in the natural laws of the two Universes."
Hallam had adopted the word "para-Universe" and made it his own at this point. Furthermore, he became the first to use the word "pump" (since invariably capitalized) in connection with the matter.
There is a tendency in the official account to give the impression that Hallam's suggestion caught fire at once, but it did not. Those who were willing to discuss it at all would commit themselves no farther than to say it was an amusing speculation. Kantrowitsch, in particular, did not say a word. This was crucial to Hallam's career.
Hallam could scarcely carry through the theoretical and practical implications of his own suggestion all by himself. A team was required and it was built up. But none of the team, until it was too late, would associate himself openly with the suggestion. By the time success was unmistakable, the public had grown to think of it as Hallam's and Hallam's alone. It was Hallam, to all the world, and Hallam alone, who had first discovered the substance, who had conceived and transmitted the Great Insight; and it was therefore Hallam who was the Father of the Electron Pump.
Thus, in various laboratories, pellets of tungsten metal were laid out temptingly. In one out of ten the transfer was made and new supplies of plutonium-186 were produced. Other elements were offered as bait and refused . . . But wherever the plutonium-186 appeared and whoever it was that brought the supply to the central research organization working on the problem, to the public it was an additional quantity of "Hallam's-tungsten."
It was Hallam again who presented some aspects of the theory to the public most successfully. To his own surprise (as he later said) he found himself to be a facile writer, and he enjoyed popularizing. Besides success has its own inertia, and the public would accept information on the project from no one but Hallam.
In a since famous article in the North American Sunday Tele-Times Weekly, he wrote, "We cannot say in how many different ways the laws of the para-Universe differ from our own, but we can guess with some assurance that the strong nuclear interaction, which is the strongest known force in our Universe, is even stronger in the para-Universe; perhaps a hundred times stronger.