"

"It's more than that," Page declared. "It conserves not only energy _in
toto_, not only the energy of the whole, but the energy of the part. It
is perfectly transparent, yet it has refractive qualities. It won't
absorb light because to do so would change its energy content. In that
field, whatever is hot stays hot, whatever is cold can't gain heat."

He scraped his hand over a week's growth of beard, considering. From his
pocket he took a pipe and a leather pouch. Thoughtfully he filled the
pipe and lit it.

It had started with his experiments in Force Field 348, an experiment to
observe the effects of heating a conductor in that field. It had been
impossible to heat the conductor electrically, for that would have upset
the field, changed it, twisted it into something else. So he had used a
Bunsen burner.

Through half-closed eyes, he still could see that slender strand of
imperm wire, how its silvery length had turned to red under the blue
flame. Deep red at first and then brighter until it flamed in almost
white-hot incandescence. And all the while the humming of the
transformer as the force field built up. The humming of the transformer
and the muted roaring of the burner and the glowing heat in the length
of wire.

Something had happened then ... an awesome something. A weird wrench as
if some greater power, some greater law had taken hold. A glove of
force, invisible, but somehow sensed, had closed about the wire and
flame. Instantly the roaring of the burner changed in tone; an odor of
gas spewed out of the vents at its base. Something had cut off the flow
of flame in the brass tube. Some force, _something_ ...

The flame was a transparent cloud. The blue and red of flame and hot
wire had changed, in the whiplash of a second, to a refractive but
transparent cloud that hung there within the apparatus.

* * * * *

The red color had vanished from the wire as the blue had vanished from
the flame. The wire was shining. It wasn't silvery; it wasn't white.
There was no hint of color, just a refractive blur that told him the
wire was there. Colorless reflection. _And that meant perfect
reflection!_ The most perfect reflectors reflect little more than 98 per
cent of the light incident and the absorption of the two per cent colors
those reflectors as copper or gold or chromium. But the imperm wire
within that force field that had been flame a moment before, was
reflecting _all_ li