not until in its stead there
lay a furiously boiling lake, its flaming surface hundreds of feet below
the level of the plain--did Stevens open his power circuits and point
the deformed prow of the _Forlorn Hope_ toward Titania.

CHAPTER VII

The Return to Ganymede

"Must you you go back to Ganymede?" Barkovis asked, slowly and
thoughtfully. He was sitting upon a crystal bench beside the fountain,
talking with Stevens, who, dressed in his bulging space-suit, stood near
an airlock of the _Forlorn Hope_. "It seems a shame that you should face
again those unknown, monstrous creatures who so inexcusably attacked us
both without provocation."

"I'm not so keen on it myself, but I can't see any other way out of it,"
the Terrestrial replied. "We left a lot of our equipment there, you
know; and even if I should build duplicates here, it wouldn't do us any
good. These ten-nineteens are the most powerful transmitting tubes known
when we left Tellus, but even their fields, dense as they are, can't
hold an ultra-beam together much farther than about six astronomical
units. So you see we can't possibly reach our friends from here with
this tube; and your system of beam transmission won't hold anything
together even that far, and won't work on any wave shorter than Roeser's
Rays. We may run into some more of those little spheres, though, and I
don't like the prospect. I wonder if we couldn't plate a layer of that
mirror of yours upon the _Hope_ and carry along a few of those bombs? By
the way, what is that explosive--or is it something beyond Tellurian
chemistry?"

"Its structure should be clear to you, although you probably could not
prepare it upon Tellus because of your high temperature. It is nothing
but nitrogen--twenty-six atoms of nitrogen combined to form one molecule
of what you would call--N-twenty-six?"

"Wow!" Stevens whistled. "Crystalline, pentavalent nitrogen--no wonder
it's violent!"

"We could, of course, cover your vessel with the mirror, but I am afraid
that it would prove of little value. The plates are so hot that it would
soon volatilize."

"Not necessarily," argued Stevens. "We could live in number one
life-boat, and shut off the heat everywhere else. The life-boats are
insulated from the structure proper, and the inner and outer walls of
the structure are insulated from each other. With only the headquarters
lifeboat warm, the outer wall could be held pretty close to zero
absolute."

"That