seemed hanging free, several feet above the crystal platforms.

Reluctantly he withdrew his eyes from the mysterious sphere and looked
about the room once more. No, the laboratory was vacant of human
occupants. No one was hidden among the benches that were cluttered
with beakers and test tubes and stills, or among the dynamos and
transformers in the other end of the room.

A confusion of questions beat through Larry's brain.

What danger could be haunting this quiet laboratory? Was this the
blood of Agnes Sterling or the scientist who employed her that was now
clotting on the floor? What terrific force had crumpled up the
revolver? What had become of Agnes and Dr. Whiting? And of whatever
had attacked them? Had Agnes called him after the attack, or before?

* * * * *

Despite himself, his attention was drawn back to the little globe
spinning so regularly, floating in the air between the pillars of red
and violet flame. Floating alone, like a little world in space,
without a visible support, it might be held up by magnetic attraction,
he thought.

A tiny planet!

His mind quickened at the idea, and he half forgot the weird mystery
gathering about him. He stepped nearer the sphere. It was curiously
like a miniature world. The irregular bluish areas would be seas; the
green and the brown spaces land. In some parts, the surface appeared
mistily obscured--perhaps, by masses of cloud.

Larry saw an odd-looking lamp, set perhaps ten feet behind the slowly
spinning, floating ball, throwing upon it a bright ray of vividly blue
light. Half the strange sphere was brilliantly illuminated by it; the
rest was in comparative darkness. That blue lamp, it came to Larry,
lit the sphere as the sun lights the earth.

"Nonsense!" he muttered. "It's impossible!"

Aroused by the seeming wonder of it, he was drawn nearer the ball. It
spun rather slowly, Larry noted, and each rotation consumed several
seconds. He could distinguish green patches that might be forests, and
thin, silvery lines that looked like rivers, and broad, red-brown
areas that must be deserts, and the broad blue stretches that
suggested oceans.

"A toy world!" he cried. "A laboratory planet! What an experiment--"

Then his eyes, looking up, caught the glistening, polished lens of a
powerful magnifying glass which hung by a black ribbon from a hook on
one of the heavy steel beams which supported the huge mass of silently
whirring