, up a flight of stairs
that was little more than a ladder, and into the cavernous loft of the
old barn which had been transformed into a laboratory.

Jim drew Denny aside a pace or two. "He says he's got something new.
Isn't he afraid to show it to a stranger like me?"

"Afraid? Why should he be?"

"Well, ideas do get stolen now and then, you know."

Denny smiled. "When Matt gets hold of something new, you can be sure the
discovery isn't a new kind of can-opener or patent towel-rack that can
be 'stolen.' His ideas are safe for the simple reason that there
probably aren't more than four other scientists on earth capable of even
dimly comprehending them. All you and I can do--whatever this may turn
out to be--is to watch and marvel."

* * * * *

Matt, meanwhile, had lumbered with awkward grace to a great wooden
pedestal. Cupping down over this was a glass bell, about eight feet
high, suspended from the roof.

Around the base of the pedestal was a ring of big lamp-affairs, that
looked like a bank of flood-lights. The only difference was that where
flood-lights would have had regular glass lenses to transmit light
beams, these had thin plates of lead across the openings. Thick copper
conduits branched to each from a big dynamo.

Matt reached into a welter of odds and ends on a bench, and picked up a
tube. Rather like an ordinary electric light bulb, it looked, save that
there were no filaments in the thin glass shell. Where filaments should
have been there was a thin cylinder of bluish-gray metal.

"Element number eighty-five," said Matt in his deep, abstracted voice,
pointing at the bluish cylinder. "Located it about a year ago. Last of
the missing elements. Does strange tricks when subjected to heavy
electric current. In each of those things that look like searchlights is
one of these bulbs."

He laid down the extra tube, turned toward a door in the near wall, then
turned back to his silent guests again. Apparently he felt they were
due a little more enlightenment.

"Eighty-five isn't nearly as radioactive as the elements akin to it," he
said. Satisfied that he had now explained everything, he started again
toward the door.

As he neared it, Dennis and Jim heard a throaty growling, and a vicious
scratching on the wooden panels. And as Matt opened the door a big
mongrel dog leaped savagely at him!

* * * * *

Calmly, Matt caught the brute by t