Black Light

by Ralph Milne Farley

THE PRESIDENT received the sandy-haired G-man in the blue room of the White House.

"Curtis," said he, with his engaging smile, "as you know, American relations are very strained with a certain foreign power, whose name I need not mention. We have just received word from the army intelligence service that spies of that power have entered this country for the purpose of making an attempt on my life. I understand that you fellows of the bureau of investigation are great believers in what you call 'occupational disguise'?"

"Yes, sir."

"And that you yourself are a reserve officer?"

"Yes, sir. Captain of infantry."

"Very well, Captain Curtis. I have arranged with your chief to give you a leave of absence. You will be called to active duty as a reserve officer, and will be detailed to the technical staff. Please obtain ordinance insignia and report back here in uniform for instructions. Your duty will be to act secretly as my bodyguard."

Walter Curtis drew himself up to attention: his steel-gray eyes snapped as he saluted briskly. "Yes, sir," he replied.

SURROUNDED by an escort of motor-cycle police, and preceded and followed by cars containing plain-clothes men of the secret service, the President's sedan drew up in front of a large white-pillared, colonial, brick house in the suburbs of Georgetown. The President, the secretary of war, Colonel Forster of the technical staff and Captain Walter Curtis, got out and ascended the broad front steps.

They were met in the doorway by a tall well-built gentleman with frowzy, iron-gray hair and bushy, black eyebrows, whom Colonel Forster introduced as Professor Woodward.

Rubbing his hands ingratiatingly, the professor escorted them inside. "Before we pass on to my laboratory," he said, "I want you to glance at this painting." He indicated a haying scene, hanging over the Sheraton wall table in the front hall; and proudly added, "I painted it myself."

There seemed to be nothing extraordinarily artistic about the picture, but all the guests politely murmured a halfhearted appreciation.

Professor Woodward raised his bushy eyebrows; his black eyes glittered. Picking up two pairs of horn-rimmed spectacles from the wall table, he handed one of them to the President, with the suggestion, "Now look at it through this, excellency."

Some sixth sense caused Walter Curtis to prick up his ears.

The President put on the glasses, peered through them at the painting. Then he exclaimed, "Why, the hay and the hayers are gone! It's an autumn scene now! The fields are brown, and the trees are all orange and red!"

He alternately removed and replaced the spectacles several times, comparing the effect; then he handed them to the secretary of war.

As the others tried them in turn, Professor Woodward gave the President the second set, dryly remarking, "These spectacles will show you the same scene in winter: snow and purple shadows."

"How do you do it?" asked the President in admiring tones, as he removed the second pair of glasses, and smiled engagingly at his host.

The professor smiled back. "Very simple," he explained. "The normal human eyes sees only one octave out of all the infinite range of the spectrum; just as though we could hear only one octave of the piano. But I have devised pigments which, although invisible to unassisted eyesight, nevertheless produce all the different colors of the octave above human vision; also the octave below.

"This picture is really three different pictures: painted once with ordinary paints, once with infra-red paints, and once with ultra-violet paints. Each of these pairs of eyeglasses shifts the wearer's color perception one octave; thus, the first pair renders infra-red colors visible, and the second pair renders ultra-violet colors visible. Simple, isn't it?"

"Simple?" breathed the President. "It's marvelous!"

Every one else chorused, "Ah!"

Professor Woodward continued: "I showed you this picture first, because I believe that it will render more understandable what you are to see in my laboratory. Gentlemen, kindly step this way." And he led the party through some doors and down a hallway toward the rear of the house.

Opening a door into a small room, he apologetically asserted, "I am afraid that there isn't room in here for any but the principals. Excellency, would you mind leaving your guards outside?"

"Certainly not." The President beamed.

Then he, the secretary of war, and the two army officers entered the little room.

Professor Woodward closed the door with a click. The room was bare except for a small table, an electrical switchboard on the wall, and a large naval searchlight standing in one corner.

Colonel Forster explained in a whisper to Walter Curtis: "That's the device which gained him decorations from practically every Allied government in the World War, and membership in the British Royal Academy!"

THE PROFESSOR began his explanation: "That is the black-light, searchlight, which safeguarded our troop ships against the German submarines. Its rays are ultra-violet, and hence invisible. A submarine would come to the surface alongside a totally dark Allied vessel; and, believing itself unobserved, would methodically get ready to loose a torpedo. Little did the Germans realize that one of these searchlights was playing full upon them."

"But what good did it do, if the rays were invisible?" asked Captain Curtis.

"Ah! You forget the spectacles which you wore in my front hall. Every bit of aiming and laying apparatus of the guns of your ships was equipped with lenses like those through which you looked at the winter scene. To your gunners, the submarine was a blaze of glory. And so, before the torpedo could be launched, a five-inch shell would blow the enemy out of the water. Now I will demonstrate."

"I hope that you do not plan to blow us all out of the water," said the President jocularly; every one laughed.

The professor took a pair of spectacles from his pocket and put them on. Then he moved over to the panel and closed a large double-leaf switch. A motor-generator set clicked, then hummed into action. Next he snapped out the lights. The lens of the searchlight glowed an eerie faint lavender, but otherwise the room was a dense blackness.

"You can tell when you are in the beams of the searchlight," the professor explained, "by looking into a mirror, for the ultra-violet light causes your eyeballs to fluoresce with a faint, greenish luminescence." He chuckled recollectively. "I used to tell folks to watch for the reflection of the teeth. Teeth are even more luminescent than eyeballs. But imagine my embarrassment when the late Sir Oliver Lodge sidled all the way across this room, mirror in hand, without any reaction! I found out afterward that his teeth were false."

A general laugh went up at this anecdote. Then Woodward let each member of the party sidle across the laboratory, holding a little hand mirror, in order to observe the phenomenon of the flashing eyeballs. G-man Curtis, being the junior in rank of those present, was the last to try this.

Then each one, in turn, put on the professor's spectacles. It was amazing how this suddenly transformed the path of the beam of the searchlight from dense blackness to a blaze of light!

Curtis still had the small hand mirror when he donned the magic glasses. Instinctively he held the mirror out into the ray, and attempted to reflect the light back onto some other part of the room. But it would not reflect!

"Ah, captain," observed their host, "I am glad that you tried that, for it suggests another point of interest about the black light. An ordinary mirror will not reflect it. But now try this mirror here." He groped in the darkness on the top of the table, picked up a square of shiny substance, and handed it to the G-man.

Curtis held it in the glare of the searchlight, and found that he was now able to flash the light back, as though it had been sunlight. Then he took off the spectacles and gave them to the professor.

A STRANGE CHANGE came into the voice of Professor Woodward—a certain tenseness and raise in pitch—as he declaimed, "And now, gentlemen, I have the glasses on again, and you have not. I can see all of you, and none of you can see me. The door is locked!" He paused momentarily, to let that thought sink in. Then he concluded dramatically, "And now, as you value your lives, let nobody move! I am going to shoot the President."

Four simultaneous gasps echoed through the little laboratory. And then Walter Curtis acted!

He still held the mirror which would reflect ultra-violet light. Thrusting it, with his left hand, in the darkness, into where he knew the invisible ray of the searchlight to be, he threw the invisible reflection in the direction from which the words had come.

Two green eyes glowed at him out of the darkness—then blinked shut.

Curtis held the mirror steady, for he realized that, with that blinding glare shining through the octave-shifting lenses, the professor would be unable to see his intended victim.

"Duck, Mr. President!" he shouted. "He can't see you now." Then he reached for the .45 automatic which hung on his belt.

The two green eyes blinked open again; and from some distance beneath them came the flash and roar of a revolver. The mirror in Curtis' left hand splintered to pieces.

But a split second later, Curtis' own weapon roared back, aimed squarely between those two phosphorescent spots.

The dull thud of a falling body. Then silence. Then insistent pounding on the door, and the sound of running feet outside.

Curtis groped to the switch panel, snapped on the lights.

The professor lay on the floor, a stream of blood oozing out from beneath his face, his glasses lying near by, and one outflung hand clutching a smoking revolver. No one else was even scratched.

More pounding on the door. The secretary of war sprang to put his arms around the President. Shakily, Colonel Forster unlocked the door; in barged the secret service detail, weapons drawn.

Meanwhile, Walter Curtis was down on his knees beside the dead body. He turned it over—and the iron-gray mop of hair came off! It was only a wig. "Your foreign spy, Mr. President," he reported.

They found the real Professor Woodward trussed up and with mouth taped, in one of the bedrooms.