"You're a calm liar, professor!" the other jeered venomously. "It says plainly that the Fifth Dimension is nothing more than a curtain of invisibility!"

"Of course," Mortenson replied evenly. "I said that, because I did not want to frighten narrow-minded people with the knowledge that on every side lurk weird, ferocious man-beasts that would annihilate them, were it possible for them to emerge from behind the veil that hides the Fifth Dimension from human vision."

The intruder glared at him, his eyes narrowed suspiciously. Then he shrugged his broad shoulders decisively.

"You've got one more minute to deliver the goods, professor!" he barked. "I want the apparatus and instructions on how to operate it. Now sit down at your typewriter and pound 'em out!"

"It's all right with me, young fellow," said Mortenson resignedly, "if you want to seal your own doom. That's what you are going to do if you do some criminal act and place yourself in the Fifth Dimension to escape apprehension. It's your life, not mine. You won't listen to reason. I hate to see it...."

"Shut up!" the other growled. "Sit down and write fast!"

"If I should refuse?" Mortenson paused at his typewriter.

"Then I'll drill you," the intruder snapped, tensing.

Mortenson hadn't a qualm of doubt but that the fellow would kill him in cold blood if he refused. And Mortenson had a great desire to live. He had just discovered a way to penetrate, neutralize and enter the invisible world of the Fifth Dimension. He was on the verge of doing great things in the world of science, and he had no intentions of removing himself from it by refusing the demands of this daring crook who was, doubtless, as dangerous as he was fearless.

As he sat down at the typewriter he had a sudden feeling that he would be doing the law-abiding citizenry a great favor by meekly writing out instructions as to how to operate the Fifth Dimensional apparatus. The daring crook would undoubtedly meet his just deserts, if he ventured behind the veil into the mysterious world of the Fifth Dimension. The law of man would not be required, he thought, to bring the man to justice. What lay beyond would see to that.