"At least he is in the Blind Spot. Let me try the ring."

He struck a match.

It was much as it had been in the restaurant, only a bit more
startling. Then the blue faded, the colour went out, and it became
transparent. For a moment. There was an effect of space and
distance that I had not noted before, almost marvellous. If I
could describe it at all, I would say a crystal corridor of a
vastness that can scarcely be imagined. It made one dizzy, even in
that bit of jewel: one lost proportion, it was height, distance,
space immeasurable. For an instant. Then the whole thing blurred
and clouded. Something passed across the face; the transparency
turned to opaqueness, and then--two men. It was as sudden as a
flash--the materialisation. There was no question. They were
alive. Watson was with the professor.

It was a strange moment. Only an hour before one of them had been
with us. It was Watson, beyond a doubt. He was alive; one could
almost believe him in the jewel. We had heard his story: "The
screen of the occult; the curtain of shadow." We had seen him go.
There was an element of horror in the thing, and of fascination.
The great professor! The faithful Watson! Where had they gone?

It was not until the colour had come back and the blue had
regained its lustre that either of us looked up. Could such a
thing be unravelled? Fenton turned the stone over thoughtfully. He
shook his head.

"In that jewel, Harry, lies the secret. I wish I knew a bit more