d sheepishly. He had
been sitting there waiting for that green line to move a full minute
after the input signal had ceased.

"Happy hypnosis," said Mike. "Let's get back to finding out which of
those tubes in the hull is giving the external field the willies."

Snookums, who had been listening carefully, rolled up and said,
"Generator tubes three, four, and thirteen. Three is out of phase by--"

"You can tell us later, Snookums," Mike interrupted rapidly. "Right now,
we'll get to work on those tubes. You were right once; I hope you're
right again."

Again the power crew swung into action.

Within five minutes Mike and Multhaus were making the proper adjustments
on the external field circuits to adjust for the wobbling of the output.

The throb wavered. It wobbled around, going up to two-point-seven cycles
and dropping back to one-point-four, then climbing again. All the time,
it was dropping in magnitude, until finally it could no longer be felt.
Finally, it dropped suddenly to a low of point-oh-five cycles, hovered
there for a moment, then vanished altogether.

"By the beard of my sainted maiden aunt," said Chief Multhaus in awe. "A
three-tube offbeat solved in less than half an hour! If that isn't a
record, I'll dye my uniform black and join the Chaplains' Corps."

Leda Crannon, looking tired but somehow pleased, said softly: "May I
come in?"

Mike the Angel grinned. "Sure. Maybe you can--"

The intercom clicked on. "Power Section, this is the bridge." It was
Black Bart. "Are my senses playing me false, or have you stopped that
beat note?"

"All secure, sir," said Mike the Angel. "The system is stable now."

"How many tubes were goofing?"

"Three of them."

"_Three!_" There was astonishment in the captain's voice. "How did you
ever solve a three-tube beat in that short a time?"

Mike the Angel grinned up at the eye in the wall.

"Nothing to it, sir," he said. "A child could have done it."

13

Leda Crannon sat down on the edge of the bunk in Mike the Angel's
stateroom, accepted the cigarette and light that Mike had proffered, and
waited while Mike poured a couple of cups of coffee from the insul-jug
on his desk.

"I wish I could offer you something stronger, but I'm not much of a
drinker myself, so I don't usually take advantage of the officer's
prerogative to smuggle liquor aboard," he said as he handed her the cup.

She smiled up at him. "That's all right; I rarely drink, and when I