"He walked in, just before the place was surrounded, engaged a table, and ordered a sumptuous meal. He told the waiter his name, said he expected a friend to join him, walked into the wash-room--and vanished! Two minutes later Anstruther and his men were on the job.

Von Kettler never came out of the wash-room, so far as anybody knows.

"In the midst of the hue and cry somebody pointed to the table that Von Kettler had engaged. There was a twenty-dollar bill upon it, and a sc.r.a.p of paper reading: 'I've kept my word. Von K.'"

Colonel Stopford looked at d.i.c.k fixedly. "Rennell, we may be fools,"

he said, "but we realize what we're up against. It's a big thing, and we're going to need all our fighting grit to overcome it. You're one of the four men we're depending on. We're counting on you because of your record, and because of your degree in science at Heidelberg. The President wishes you to take charge of the whole Eastern Intelligence District, covering the entire south-eastern seaboard of the United States. You are to have complete freedom of action, and all civil, military, and naval officials have received instructions to co-operate with you."

"There goes Mrs. Wansleigh's ball," thought d.i.c.k, but he said nothing.

"We're not the hunters, d.i.c.k Rennell," went on Colonel Stopford.

"We're hiding under cover, and I'm counting on you to turn the tables.

They even know my office is here. I had a long distance call from Savannah this morning in mocking vein. They advised me to have the White House watched to-night. I warned the President, and we've posted guards all round it."

"They held the wire while you called up the President?" asked d.i.c.k.

"d.a.m.n it, no! They called me up from Scranton the instant he'd finished speaking. They have the power of the devil, Rennell, with that infernal invisibility invention of theirs. Rennell, we're fighting unknown forces. Who this Invisible Emperor is, we don't even know. But one thing we've found out. He has his headquarters somewhere in your district. Somewhere along the south Atlantic seaboard. The greater part of his activities emanate from there. But we're fighting in the dark. The clue, the master clue that will enable us to locate him--that's what we lack."

The sun had set, it was beginning to grow dark. Colonel Stopford switched on the electric lamp beside his desk.

"What have you to say, Rennell?" he asked; and d.i.c.k was aware that the two other men were regarding him attentively.

"It's evident," said d.i.c.k, "that Von Kettler possessed this means of invisibility in his cell, and wasn't detected. He simply slipped out when the guard came to fetch him."

"Invisibility? Yes! But invisible's not the same thing as transparent," cried Stopford. "These folks have operated in broad daylight. They're transparent, d.a.m.n them! Not even a shadow! You know what I mean, Rennell! What I'm thinking of! That crazy man you were in touch with six months ago, who prophesied this! We turned him down! He showed me a watch and said the salvation of the world was inside the case! I thought him insane!"

"You mean Luke Evans, sir. That watch was his pocket model. He went off in a huff, saying the time would come when we'd want him and not be able to find him."

"But, d.a.m.n him, he wanted to produce universal darkness, or some such nonsense, Rennell, and I told him that we wanted light, not darkness."

"It wasn't exactly that, sir." Colonel Stopford was a man of the old school: he had been an artillery officer in the Great War, and was characteristically impatient of new notions. d.i.c.k began carefully: "You'll remember, sir, old Evans claimed to have been the inventor of that shadow-breaking device that was stolen from him and sold in England."

"To a moving picture company!" snorted Stopford. "I asked him what moving pictures had to do with war."

"Evans was convinced that the invention would be applied to war. He claimed that it made the modern methods of military camouflage out of date completely. He said that by destroying shadows one could produce invisibility, since visibility consists in the refraction of wave lengths by material objects.

"When they stole his invention, he foresaw that it would be used in war. He set to work to nullify his own invention. He told me that he had unintentionally given to the enemies of the United States a means of bringing us to our knees, since he believed that British motion picture company was actually a subsidiary of Krupp's. He worked out a method of counteracting it."

"You must get him, Rennell. Even if it's all nonsense, we can't afford to let any chance go. If Evans's invention will counteract this d.a.m.ned invisibility business--"

The telephone on the Colonel's desk rang. He picked it up, and his face a.s.sumed an expression of incredulity. He looked about him, like a man bewildered. He beckoned to the police official, who hurried to his side, and thrust the receiver into his hand. The official listened.

"All right," he said. He turned to d.i.c.k and the Civil Service representative.

"Gentlemen," he said, "the President has disappeared from his office in the White House, and there are grave fears that he has been kidnapped!"

CHAPTER III

_In the White House_

Colonel Stopford's car had been parked around the corner of the building, and within a minute the four men were inside it, Stopford at the wheel, and racing in the direction of the White House. A nod to the guard at the gate, and they were inside the grounds. At the entrance a single guard, in place of the four who should have been posted there, challenged sharply, and attempted to bar the way, not recognizing d.i.c.k or Stopford in their civilian clothes.

"Where's your officer?" demanded Stopford sharply.

Half-cowed by the Colonel's manner, the young recruit hesitated, and the four swept him out of the way and hurried on. The scene outside the main entrance to the White House was one of indescribable confusion. Soldiers were swarming in confused groups, some trying to force an entrance, others pouring out. Every moment civilians, streaming over the lawn, added to the number. Discipline seemed almost abandoned. From inside the building came outbursts of screams and cursing, the scuffling of a mob.

"Roscoe! Roscoe!" shouted Stopford. "Where's the President's secretary? Who's seen him? Let us pa.s.s immediately!"

No one paid the least attention to him. But a short, bare-headed civilian, who was struggling in the crowd, heard, and shouted in answer, waved his arms, and began to force his way toward the four. It was Roscoe, the secretary of President Hargreaves. The President was a childless widower, and Roscoe lived in the White House with him and was intimately in his confidence.

Roscoe gained Stopford's side. "Say--they've got him!" he panted.

"They've got him somewhere--inside the building. They're trying to get him out! We've got to save him--but we can't see them--or him. They've made him invisible too, curse them! I heard him crying, 'Help me, Roscoe!' He saw me, I tell you--and I didn't know where he was!"

The little secretary was almost incoherent with fear and anger. The five men, forming a wedge, hurled themselves forward. Out of the White House entrance appeared a tall officer, revolver in hand. It was Colonel Simpson, of the President's staff. Half beside himself, he swept the weapon menacingly about him, shouting incoherently, and clearing a pa.s.sage, into which the five hurled themselves.

Stopford seized his revolver hand, and after a brief struggle Simpson recognized him.

"He's in the building!" he shouted wildly. "Somewhere upstairs! I'm trying to form a cordon, but this d.a.m.ned mob's in the way. Kick those civilians out!" he cried to the soldiers. "Shoot them if they don't go! Guard the windows!"

Stopford and d.i.c.k, at the head of the wedge, pushed past into the White House. The interior was packed, men were struggling frantically on the staircase; it seemed hopeless to try to do anything.

Suddenly renewed yells sounded from above, a scream of anguish, howls of terror. There came a downward surge, then a forward and upward one, which carried the two men up the stairs and into the President's private apartments above.

In the large reception-room a mob was struggling at a window, beneath a blaze of electric light. A soldier was standing there like a statue, his face fixed with a leer of horror. In his hands was a rifle, with a blood-stained bayonet, dripping upon the hardwood floor at the edge of the rug. Upon the rug itself a stream of blood was spouting out of the air.

d.i.c.k looked at the sight and choked. There was something appalling in the sight: it was the quintessence of horror, that widening pool of blood, staining the rug, and flowing from an invisible body that writhed and twisted, while moans of anguish came from unseen lips.

Colonel Stopford leaped back, livid and staring. "G.o.d, it's got eyes--two eyes!" he shouted.

d.i.c.k saw them too. The eyes, which alone were visible, were about six inches from the floor, and they were appearing and disappearing, as they opened and shut alternately. It was a man lying there, a dying man, pierced by the soldier's bayonet by pure accident, dying and yet invisible.

The mob had scattered with shrieks of terror, but a few bolder spirits remained in a thin circle about that fearful thing on the rug. d.i.c.k bent over the man, and felt the outlines of the writhing body. It was a man, apparently dressed in some sort of uniform, but this was covered, from the top of the head to the feet, with a sort of sheer silken garment, bifurcating below the waist, and resembling a coc.o.o.n.

It seemed to appear and alternately to vanish.

d.i.c.k seized the filmy stuff in his fingers, rent it, and stripped it away. Yells of terror and amazement broke from the throats of all.

Instantly the thin circle of spectators had become reinforced by a struggling ma.s.s of men.

The half-visible coc.o.o.n clung to d.i.c.k's body like spider webs. But the man who had been wearing it had sprung instantly into view beneath the cl.u.s.ter of electric lights. He was a fair-haired young fellow of about thirty years, his features white and set in the agony of death.

He was dressed in a trim uniform of black, with silver braid, and on his shoulders were the insignia of a lieutenant. He opened his eyes, blue as the skies, and stared about him. He seemed to understand what had happened to him.