And Isobar played on. How, or what, he did not know. The memory of those next few minutes was never afterward clear in his mind. All he knew was that above the skirling drone of his pipes there came another sound, the metallic clanking of a man-made machine ... an armored tank, sent from the Dome to rescue the beleaguered trio.
He was conscious, then, of a friendly voice shouting words of encouragement, of Joe Roberts calling a warning to those below.
"Careful, boys! Drive the tank right up beneath us so we can hop in and get out of here! Watch the Grannies—they'll be after us the minute Isobar stops playing!"
Then the answer from below. The fantastic answer in Sparks' familiar voice. The answer that caused the bagpipes to slip from Isobar's fingers as Isobar Jones passed out in a dead faint:
"After you? Those Grannies? Hell's howling acres—those Grannies are stone dead!"
Afterward, Isobar Jones said weakly, "But—dead? I don't understand. Was it the sound-waves that killed them?"
Commander Eagan said, "No! Grannies absolutely cannot hear. That is one thing we do know about them—though we will soon know a great deal more, now that our biologists have a dozen carcasses to dissect, thanks to you. But Grannies have no auditory apparatus."
"But then—what?" puzzled Isobar. "It couldn't be vibration, because our Patrolmen tried shootin' 'em with the vibro-ray pistol, and nothin' never happened—"
"Nevertheless," said Dr. Loesch quietly, "it was vibration which killed them, Isobar. That is, of course, only my conjecture, but I believe subsequent study will prove I am correct.