Cochrane nodded. It occurred to him that Jones was very much unlike Dabney. Jones had discovered the Dabney field, but having sold the fame-rights to it, he now apparently thought "Dabney Field" was the proper technical term for his own discovery, even in his own mind.
"Back on the moon," Jones went on zestfully, "I wasn't sure that a field once established would hold in atmosphere. I hoped that with enough power I could keep it, but I wasn't sure—"
"This doesn't mean much to me, Jones," said Cochrane. "What does it add up to?"
"Why—the field held down into atmosphere. And we were out of the primary field as far as the tail of the ship was concerned. But this time we landed, I'd hooked in some ready-installed circuits. There was a second Dabney field from the stern of the ship to the bow. There was the main one, going out to those balloons and then back to Earth. But there was—and is—a second one only enclosing the ship. It's a sort of bubble. We can still trail a field behind us, and anybody can follow in any sort of ship that's put into it. But now the ship has a completely independent, second field. Its tail is never outside!"
Cochrane did not have the sort of mind to find such information either lucid or suggestive.
"So what happens?"
"We have both plates of a Dabney field always with us," said Jones triumphantly. "We're always in a field, even landing in atmosphere, and the ship has practically no mass even when it's letting down to landing. It has weight, but next to no mass. Didn't you notice the difference?"
"Stupid as it may seem, I didn't," admitted Cochrane. "I haven't the least idea what you're talking about."
Jones looked at him patiently.
"Now we can shoot our exhaust out of the field! The ship-field, not the main one!"