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 the 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."