With a bow he withdrew, and they heard a massive bolt slide into
the socket of a door hidden behind a curtain. The two men gazed
at each other without speaking, for a moment, and then they began
to inspect the room.

In alcoves half-veiled with silken curtains stood statues in gold
and bronze. The walls and ceilings were decorated with pictures
unlike any they had ever seen. Before one, the picture of an
angel flying through a dark, star-filled sky, they both stood
enchanted.

"What is it?" asked Thorndyke, finding voice finally. "It is not
done with brush or pencil; the features seem alive and, by Jove,
you can actually see it breathe. Don't you see the clouds gliding
by, and the wings moving?"

"It is light--it is formed by light!" declared the other
enthusiastically, and he ran to the wall, about six feet from the
picture, and put his hand on a square metal box screwed to the
wall.

"I have it," he said quickly, "come here!"

The Englishman advanced curiously and examined the box.

"Don't you see that tiny speck of light in the side towards the
picture? Well, the view is thrown from this box on the wall, and
it is the motion of the powerful light that gives apparent life
to the angel. It is wonderful."