He shivered a trifle as he thought of it. Swiftly his fingers flew over the typewriter. Meanwhile the crook stood over him, glaring hostilely, his gun in readiness to send instant death into the man whose life had been spent delving into the mysteries of the dimensions. The ignorant fellow could not know what was in store for him, and he had refused to listen to cold reason. Mortenson's warning had come from the heart. He had seen what lay behind the veil, and had been so sick and nauseated at what he saw, that he had slept little for some nights thereafter. But let the obstinate fellow go. Mortenson yanked a sheet of paper from his typewriter, glancing over it quickly and stood erect. "There you are, my friend," he said with a shrug. "The instructions are full and complete. I'll get the apparatus for you." "Mortenson," the man snapped coldly. "If you've bunked me I'll come back and blast you into hell! Get that?" "Never fear, young man," the scientist said, eyeing the fellow squarely. "The instructions are perfect and simple. Follow them to your doom. Now for the apparatus...." "Just a minute, professor," the crook cut in. "You got any plans for the apparatus?" Mortenson glanced at him shrewdly, suspiciously. He shook his head. "No, I have not," he lied glibly. "I have no way of duplicating the apparatus, if that's what you mean." "That's it exactly," the other sneered. "If you're lying--" "I'm not!" the scientist grumbled. "I have not yet had time to make plans or illustrations. Not getting cold feet, are you?" The man laughed peculiarly. "Do I look yellow?" he grunted. Mortenson agreed silently that he certainly did not look like a coward. But maybe the yellow streak would show up afterward, when it was too late to save himself. He smiled grimly and turned his back on the man. Quickly he strode to a big steel vault that stood in one corner of the room. The doors hung open. He bent over and removed a strange-looking helmet and an oval apparatus to which was attached a wide metal belt. Wires ran down from the helmet and hung loosely with small plugs dangling at the ends. In front of the helmet were firmly attached two projecting tubes. With the helmet in place on a man's head, these tubes fitted in front of the eyes, like field glasses.