a-stubby wings and
vanes, with flush-set rocket ports everywhere, built of a lustrous,
silvery alloy of noble and almost infusible metals--such was the private
speedboat of Triplanetary's head man. The fastest thing known, whether
in planetary air, the stratosphere, or the vacuous depth of
interplanetary space, her first flashing trial spins had won her the
nickname of the _Silver Sliver_. She had had a more formal name, but
that title had long since been buried in the Departmental files.

Lower and lower dropped the speedboat, her rockets flaming ever
brighter, until her slender length lay level with the airlock door. Then
her blasting discharges subsided to the power necessary to match exactly
the _Chicago's_ acceleration.

"Ready to cut, _Chicago_! Give me a three-second call!" snapped from the
pilot room of the _Sliver_.

"Ready to cut!" the pilot of the _Chicago_ replied. "Seconds! Three!
Two! One! CUT!"

At the last word the power of both vessels was instantly cut off and
everything in them became weightless. In the tiny airlock of the slender
plane crouched a space-line man with coiled cable in readiness, but he
was not needed. As the flaring exhausts ceased Cleveland swung out his
heavy bag and stepped lightly off into space, and in a right line he
floated directly into the open port of the rocket-plane. The door
clanged shut behind him and in a matter of moments he stood in the
control room of the racer, divested of his armor and shaking hands with
his friend and co-laborer, Frederick Rodebush.

"Well, Fritz, what do you know?" Cleveland asked, as soon as greetings
had been exchanged. "How do the various reports dovetail together? I
know that you couldn't tell me anything on the wave, but there's no
danger of eavesdroppers _here_."

"You can't tell," Rodebush soberly replied. "We're just beginning to
wake up to the fact that there are a lot of things we don't know
anything about. Better wait until we're back at the Hill. We have a full
set of ultra screens around there now. There's a couple of other good
reasons, too--it would be better for both of us to go over the whole
thing with Virgil, from the ground up; and we can't do any more talking,
anyway. Our orders are to get back there at maximum, and you know what
that means aboard the _Sliver_. Strap yourself solid in that
shock-absorber there, and here's a pair of ear-plugs."

"When the _Sliver_ really cuts loose it means a rough party, all right,"
Cl