ven's hot," and the man left his bench. Taking up a long
paddle and an even longer blowpipe, he skimmed the melt to a dazzlingly
bright surface and deftly formed a bubble.

"I just love to talk at you when you've got your mouth full of a
blowpipe." Nadia eyed him impishly and tucked her feet beneath her,
poised weightless as she was. "I've got you foul now--I can say anything
I want to, and you can't talk back, because your bubble will lose its
shape if you do. Oh, isn't that a beauty! I never saw you blow anything
that big before," and she fell silent, watching intently.

Slowly there was being drawn from the pot a huge, tapering bulb of hot,
glistening glass, its cross-section at the molten surface varying as
Stevens changed the rate of draw or the volume of air blown through the
pipe. Soon that section narrowed sharply. The glass-blower waved his
hand and Nadia severed the form neatly with a glowing wire, just above
the fluid surface of the glass remaining in the pot. Pendant from the
blowpipe, the bulb was placed over the hot-bench, where Stevens, now
begoggled, begloved, and armed with a welding torch, proceeded to fuse
into the still, almost plastic, glass sundry necks, side-tubes, supports
and other attachments of peculiar pattern. Finally the partially
assembled tube was placed in the annealing oven, where it would remain
at a high and constant temperature until its filaments, grids, and
plates had been installed. Eventually, in that same oven, it would be
allowed to cool slowly and uniformly over a period of days.

* * * * *

Thus were performed many other tasks which are ordinarily done either
by automatic machinery or by highly skilled specialists in labor--for
these two, thrown upon their own resources, had long since learned how
much specialization may be represented by the most commonplace article.
Whenever they needed a thing they did not have--which happened every
day--they had either to make it or else, failing in that, to go back and
build something that would enable them to manufacture the required item.
Such setbacks had become so numerous as to be expected as part of the
day's work; they no longer caused exasperation or annoyance. For two
days the two jacks-of-all-trades worked at many lines and with many
materials before Stevens called a halt.

"All x, Nadia. It's time for us to stop tinkering and turn into
astronomers. We've been out for fifty I-P hours, and we'd