he throat and held it away from him at
arm's length, seeming hardly to be aware of its eighty-odd pounds of
struggling weight. Into Jim's eyes crept a glint of admiration. It was a
feat of strength as well as of animal management; and, himself
proficient in both, Jim could accord tribute where it was due.

"You came just as I was about to try an experiment on the highest form
of life I've yet exposed to my new rays," he said, striding easily
toward the glass bell with the savage hound. "It's worked all right with
frogs and snakes--but will it work with more complex creatures?
Mammalian creatures? That's a question."

Denny forbore to ask him what It did, how It worked, what the devil It
was, anyway. From his own experience he knew that the abstraction of an
experimenter insulates him from every outside contact. Matt, he
realized, was probably making a great effort to remain aware that they
were there in the laboratory at all; probably thought he had explained
in great detail his new device and its powers.

Vaguely wrapped in his fog of concentration, Matt thrust the snarling
dog under the bell, which he lowered quickly till it rested on the
pedestal-floor and ringed the dog with a wall of glass behind which it
barked and growled soundlessly.

Completely preoccupied again, Matt went to a big switch and threw it.
The dynamo hummed, raised its pitch to a high, almost intolerable
keening note. The ring of pseudo-searchlights seemed in an ominous sort
of way to spring into life. The impression must have been entirely
imaginary; actually the projectors didn't move in the slightest, didn't
even vibrate. Yet the conviction persisted in the minds of both Jim and
Dennis that some black, invisible force was pouring down those conduits,
to be sifted, diffused, and hurled through the lead lenses at the dog in
the bell.

* * * * *

Thrilled to the core, not having the faintest idea what it was they were
about to see, but convinced that it must surely be of stupendous import,
the two stared unwinkingly at the furious hound. Matt was staring, too;
but his glance was almost casual, and was concentrated more on the glass
of the bell than on the experimental object.

The reason for the direction of his gaze almost immediately became
apparent. And as the reason was disclosed, Dennis and Jim exclaimed
aloud in disappointment--at the same time, so intense was their nameless
suspense, not knowing they ha