ne of the faster of the alien boats
detached itself from the others and trailed along in their wake.

"Better slip that fellow," advised the girl. "We don't want him tagging.
If we keep well in he won't be able to see us long."

Gregory gave Bronson the necessary orders, and the _Richard_ bounded
away from her pursuer and raced into the shadows of the cliff. When they
arrived at the point near the Hell-Hole Isthmus, the speed-craft motor
began to miss and Bronson guided the _Richard_ in the lea of the
promontory and threw out an anchor.

"Good place to fix that right now," he said. "You see everything's new
and I've been feeding too much oil. The plugs are all gummed up. 'Twon't
take but a minute to clean them."

While he worked over the motor Gregory's eyes roamed shoreward to the
cliffs. It was quite dark now and only the sound of the lapping waves
betokened the presence of the jagged rocks which projected above the
surface of the water near the shore. It was almost here he remembered
suddenly that the _Sea Gull_ had been wrecked. As he looked out into the
darkness, he felt Dickie's fingers tighten on his arm.

"Look!" she cried. "What's that behind us?"

Gregory turned about to see the black waters to the sternward were
rippled with sparkling threads of silver-white. From out the darkness
came a swiftly moving gray shadow. One glance astern caused Bronson to
slash the anchor-rope which held the _Richard_. Then he started the
auxiliary motor and threw the speed-craft forward with a jerk. The same
instant a long gray hull brushed by them and disappeared into the gloom
as silently as she had come. Bronson whirled the _Richard_ about, gazing
intently after the departing stranger.

"A miss is as good as a mile," he observed. "If it hadn't been for the
dual motor we'd have been out of luck."

"I wouldn't say so," Hawkins snapped. "A miss of a mile wouldn't give a
man heart-failure. Lord, I'm weak as a cat."

Kenneth Gregory leaned closer and spoke in a voice which only the
boatman could hear. Bronson put about at his words and muffling down,
followed silently after the gray boat.

"Cut out your lights."

Bronson threw the switch at Gregory's command.

"It's against the law," he muttered, "but I reckon it's safer with a
bird like that."

Soon the strange craft was again dimly visible, appearing like a gray
blot in the darkness ahead. Off the Hell-Hole she turned shoreward and
was lost to view.

"Tell him t