outer edge."

It was the scientist's turn to nod.

"Precisely my own view."

Moving away, he selected a candlestick and candle from among the gifts
on display. He handed it to Mark.

"I want you to move this stick in front of that glass," he instructed.
"However, you must be careful to stand well to one side, so that you,
yourself, will not be reflected."

"What's the angle, professor? What do you expect to find? What's wrong
with this mirror?"

The elder man shook his head, moved to a point where he could watch the
surface of the glass.

"I do not know what to expect," he said. "I may be completely on the
wrong track."

But his flashing eyes denied the words.

Seething with curiosity and excitement though he was, Mark carefully
carried out his instructions. He moved the candlestick back and forth
and up and down until it had been reflected from every inch of the
mirror. And the farther he progressed, the more excited Elaine's father
became.

"The reflection is perfect!" the old man cried. "It is true! Nowhere is
there a single sign of distortion!"

"Yes. Of course it's true." Mark was a little bewildered. "Why shouldn't
it be? Isn't every looking-glass supposed to throw back a reasonably
exact image?"

"Of course, of course!" The scientist was impatient. "But can you not
see the difference?"

"The difference? What difference?"

"Mark: this is not an ordinary mirror. That is what I mean! It denies
every law of optics! Glass as full of waves and ripples as this
apparently is should return hideously distorted reflections. Yet it does
not do so!"

"But what--"

"We shall see. Come on! Bring the mirror to my laboratory."

Hesitating only long enough to throw a tablecloth across the face of the
glass, the old man hurried out. Mark strode along in his wake, the heavy
mirror in his arms. Together, they left the house and followed the
bricked path to the little laboratory structure located at the far end
of the lot.

"Set it down here, in this rack," the professor instructed, indicating
an easel-like arrangement in one corner. He himself wheeled a strange
electrical apparatus into position in front of the glass. Then took up a
position behind a large glass screen, and motioned Mark to join him.

"What are you going to do?"

"You shall see!"

* * * * *

The white-haired savant threw a switch. The laboratory's lights went
out. He pressed a button on the control board o