"You see, chief," Mortenson said finally, "our visionary organs behold only the colors of the spectrum. Below and above each individual color is a deeper shade which our eyes cannot perceive because of the high or low vibrations of light, whichever the case may be. Now the Fifth Dimension lies above the violet shade. Physical science calls this 'color' the ultra-violet. It is a vast, invisible realm in itself, as invisible to us as our own world is to the creatures who inhabit the Fifth Dimension. It is invisible because of the rapid vibratory oscillation of its light scale. Color or rather ether waves have high light scales of vibration, too rapid or too slow to be perceived by the naked human eye. On each of these scales lie vast realms, some teeming with life of primitive or advanced state, others absolutely blank because of adverse electronic conditions.
"Taking the scale of light offered by the ultra-violet as my field of study and experiment, I succeeded in neutralizing the veil of invisibility, that enshrouds the Fifth Dimension. In doing this I overcome the vibrations of light and electrical current. By applying these oscillations to the physical body through the instrument I devised, and which, incidentally, was stolen from me last night, I was able to transfer my own body from our world to the realm of the Fifth Dimension. These vibrations and electronic movements, when applied to the physical body, cause it to become invisible at once and automatically transfer it to the particular scale to which they are aligned.
"By adapting certain prismatic lenses to my eyes, I was able to visit and to perceive this ultra-violet world and all that exists in it within range of vision. You can imagine my amazement when I beheld a world of solids, that was tinted with a pale violet shade, as the earth is with gold at times of sunset. And my apparatus had placed me right in the midst of death and destruction! The Fifth Dimension teems with primitive life; is inhabited by strange creatures, armed with primitive but deadly weapons.
"That was my first venture into the realm of the Fifth Dimension, my dear Chief. And in my horror and fear I transferred myself back to our own world before the creatures recovered sufficiently from their surprise at seeing me to attack. I was afraid to venture there again, alone, and was working on a new form of weapon for defense, when I was held up and robbed of the instrument that made my visit to the ultra-violet realm possible. This phantom bandit is undoubtedly the very man who stole my apparatus, but for the life of me, I cannot understand how he manages to enter the Fifth Dimension and remain for any length of time, without being destroyed by the creatures who live there!"
Chief Steckel eyed him strangely, perhaps a trifle incredulous in his expression.
"You really mean then, Mortenson," he said softly and in a baffled tone, "that this vanishing killer-bandit can rob and murder and hide behind a curtain of invisibility beyond the reach of the law?"
"That gives us exactly his reason for taking my apparatus," said the scientist, "and obviously for what he is doing now, hiding somewhere in the Fifth Dimension, safe from human apprehension!"
"Good Lord, man!" Steckel exploded suddenly. "Does that mean we'll never have a chance to grab him?"
Professor Mortenson smiled shrewdly. "You'll never lay hands on him, Steckel," he said flatly. "Unless you give me your aid in carrying out a plan I have already devised. Even then it may be impossible, but we can try. Meanwhile this criminal is going to go about his way killing and robbing at will and may, at this very moment, be in this room!"
Steckel's face paled and his eyes flashed. Mechanically he glanced around as though searching for some imaginary eavesdropper. But Mortenson quickly placed him at ease.