"Was that O.K.?" the fire control officer asked. "We can't tell whether we hit or not."

"I doubt if you could miss even a white dwarf star at this range," Roysland said. "But you're right, of course; there's no way of being absolutely positive." He turned back to the captain. "Let's play around with this for a while. Make a few passes, back and forth at that star and let's see what we get on the recorders."

What they got didn't look like much.

"Here's the background noise," Kiffer said, pointing at the graph. "This time, it's almost a perfect sine wave; it's the backwash from the drive generators. Here's the harmonic generated when the aJ's go off. And here"—he pulled a strip from the differential analyzer—"are the components. This one is the container phase for the energy envelope that holds the raw violence of the beam itself. And this is the carrier wave phase."

Roysland looked at the graphs and shook his head slowly. "And it all looks perfectly harmless."

"Looks, hell!" said Kiffer. "It is harmless. Believe me, Roysland, it is definitely not the backwash from the aJ guns that's causing the mindjammer effect. We'll have to look somewhere else."

"I guess you're right," Roysland agreed reluctantly. "If it isn't here—" His voice trailed off. He was right back where he started, and he didn't have anything to go on. Finally, he reached over to the intercom and punched for the bridge. "O.K., captain," he said, "let's turn the thing around and go home!"

Two weeks after the X-69 landed at Grand Base, Roysland still was stewing around, trying to make sense out of all the data he had.

Report from Bilford Vell, Chief Psychometrist: "The patients seem to be responding fairly well under the microwave treatment. It seems to act very similarly to the electro-shock treatments reputedly used centuries ago for certain types of insanity, although without the deleterious effects. The feedback loop in the prefrontal lobes is partially canceled out when the frequencies of the cerebral activities are the same as, and ninety degrees out of phase with, the microwaves beamed at the head.

"Naturally, this means that a series of treatments is necessary, since the cerebral frequencies are unpredictable and variable, and since the currents in the feedback loop are composed of a number of different frequencies."