ms--stepping them up to higher power."

"_What of it?_" demanded the skipper, rumbling.

"They believe," said Baird, "that they can handle the _Niccola_ with
their beefed-up tractor beams." He wetted his lips. "They're going to tow
us to the oxygen planet ahead, sir. They're going to set us down on it.
They'll help us find the metals we need to build the tools to repair the
_Niccola_, sir. You see the reasoning, sir. We turned them loose to
improve the chance of friendly contact when another human ship runs into
them. They want us to carry back--to be proof that Plumies and men can be
friends. It seems that--they like us, sir."

He stopped for a moment. Then he went on reasonably;

"And besides that, it'll be one hell of a fine business proposition. We
never bother with hydrogen-methane planets. They've minerals and
chemicals we haven't got, but even the stones of a methane-hydrogen
planet are ready to combine with the oxygen we need to breathe! We can't
carry or keep enough oxygen for real work. The same thing's true with
them on an oxygen planet. We can't work on each other's planets, but we
can do fine business in each other's minerals and chemicals from those
planets. I've got a feeling, sir, that the Plumie cairns are
location-notices; markers set up over ore deposits they can find but
can't hope to work, yet they claim against the day when their scientists
find a way to make them worth owning. I'd be willing to bet, sir, that
if we explored hydrogen planets as thoroughly as oxygen ones, we'd find
cairns on their-type planets that they haven't colonized yet."

The skipper stared. His mouth dropped open.

"And I think, sir," said Baird, "that until they detected us they thought
they were the only intelligent race in the galaxy. They were upset to
discover suddenly that they were not, and at first they'd no idea what
we'd be like. But I'm guessing now, sir, that they're figuring on what
chemicals and ores to start swapping with us." Then he added, "When you
think of it, sir, probably the first metal they ever used was
aluminum--where our ancestors used copper--and they had a beryllium age
next, instead of iron. And right now, sir it's probably as expensive for
them to refine iron as it is for us to handle titanium and beryllium and
osmium--which are duck soup for them! Our two cultures ought to thrive as
long as we're friends, sir. They know it already--and we'll find it out
in a hurry!"

The skipper's mouth m