There was the thing he actually feared!
He drew it into his thoughts, slowly, and analysed it. Item: he had discovered a means of controlling gravity. Item: he had developed a mechanism which worked on that principle. Addenda: the mechanism could lift a human being, quite possibly as much mass as a heavy tank, and it might even open the way to interplanetary travel.
Quite obviously, it had terrific potentialities as a weapon of war.
And it was his patriotic duty, as a citizen of the United States, to turn his discovery over to the authorities.
Well, suppose he did? It would come as an even greater shock than was the development of the atomic bomb—of that, he was sure. It would become a top-secret project. Gradually, each individual unit of the entire Armed Forces would be made airborne. The Infantry would take to the skies, supported by airborne artillery and tanks; the Air Force and Navy would combine to send giant battleships gliding through the stratosphere, unhindered by any shore-line and capable of both artillery fire and aerial bombardment.
How could anything as big as that be kept secret? The answer was, it couldn't. Such a program would hardly have begun when some Russian agent handed the entire secret over to his bosses in the Kremlin. Then Russia would launch the same sort of program.
And world tension was already terrific. Mankind was already teetering on the brink of atomic war. What psychological effect would this new threat have on them? What insults would the diplomats think of, then? What charges and counter-charges would hurl between them? What final "incident" would spark the entire civilization into a raging holocaust?
Or would the officials in Washington realize that outcome? Would they order his discovery destroyed, forgotten, and himself assigned to some well-guarded hunting lodge in the Canadian Northwest where he could be kept in comfortable isolation, with no one around to pluck the dreadful secret from his mind?
The present balance of power had at least some promise of averting an atomic war. His discovery would destroy that balance of power, and do it suddenly, frighteningly. Someone might get just scared enough to start shooting. After that, there'd be no turning back. There would be atomic war.
They probably wouldn't want their balance of power destroyed. At least, not that way.