space-ship, and the two vessels once more
hurtling together through the ether toward Titan, he turned to his
companion.

"Take the controls, will you, Nadia? Think I'll finish up the tube. I
brought along a piece of platinum from the power plant, and something
that I think is tantalum from Barkovis' description of it. With those
and the fractions we melted out, I think I can make everything we'll
need."

Now that he had comparatively pure metal with which to work, drawing
the leads and filaments was relatively a simple task. Working over
the hot-bench with torch and welding projector, he made short work of
running the leads through the almost plastic glass of the great tube and
of sealing them in place. The plates and grids presented more serious
problems; but they were solved and, long before Titan was reached, the
tube was out in space, supported by a Titanian tractor beam between the
two vessels. Stevens came into the shop, holding a modified McLeod gauge
which he had just taken from the interior of the tube. When it had come
to equilibrium, he read it carefully and yelled.

"Eureka, little fellow! She's down to where I can't read it, even on
this big gauge--so hard that it won't need flashing--harder than any
vacuum I ever got on Tellus, even with a Rodebush-Michalek super-pump!"

"But how about occluded and absorbed gas in the filaments and so on when
they heat up?" demanded Nadia, practically.

"All gone, ace. I out-gassed 'em plenty out there--seven times, almost
to fusion. There isn't enough gas left in the whole thing to make a deep
breath for a microbe."

He took up his welding projector and a beam carried him back to the
tube. There, in the practically absolute vacuum of space, the last
openings in the glass were sealed, and man and great transmitting tube
were wafted lightly back into the Terrestrial cruiser.

Hour after hour mirrored Titanian sphere and crude-fashioned terrestrial
wedge bored serenely on through space, and it was not until Titan loomed
large beneath them that the calm was broken by an insistent call from
Titan to the sphere.

"Barkodar, attention! Barkodar, attention!" screamed from the speakers,
and they heard Barkovis acknowledge the call.

"The Sedlor have broken through and are marching upon Titania. The order
has gone out for immediate mobilization of every unit."

"There's that word 'Sedlor' again--what are they, anyway, Steve?"
demanded Nadia.

"I don't know. I was goi