"In the library. He indicated that book and said something to me."

He leaped onto the chair in his excitement and grasped my shoulders with his hands. We stood thus eye to eye. "Please!" he begged. "Try to remember! What did he say?"

"Perhaps you had better tell me what this is all about, Mr...?"

"Rumplestein. However, believe me, Professor Clarke, it is much better if you do not know."

I shook my head, displaying what my colleagues occasionally call a streak of stubbornness. "You have upset me considerably. I feel I am due some explanation."

"No! No! No!" He shook his little head vigorously each time.

"Then I cannot recollect what this man said to me."

He groaned in dismay and stepped off the chair to the floor. "Very well," he said, finally. "You force me to reveal this." I waited patiently. His head snapped erect. His body stiffened. "I am engaged in a highly secret mission, the purpose of which is to prevent the collapse of this city."

I frowned. "You're not serious, of course."

"I have never been more serious in my life!"

"Quem Jupiter vult perdere, dementat prius."

"What?"

"Whom Jupiter wishes to ruin, he first drives mad," I said.

"You think I'm crazy?"

I didn't like the gleam in his eye and the tightly pressed lips. I hastily decided I was better off with him gone. These little people, I am told, can sometimes get extremely violent.

"I most certainly do," I said, "but that is none of my affair. I will tell you what that man said and then I would appreciate your popping out of my life as you so unceremoniously popped into it."

"What did he say?" He leaned forward waiting, it would seem, as if the fate of the world hung in the balance.

"Eight-thirty tonight. You know the place."

The little man studied the paper, repeating the words. Then he emitted a shriek of ecstasy. "That's it! Now the message is clear! Thank you, Professor Clarke. You have performed a duty towards society and your city." He fled down the hall. I heard the front door slam and returned to my work with a sigh of relief.

About eleven o'clock the same evening, weary in body and mind, I was preparing for bed when there came what I can only describe as a feeble but urgent rapping on my door. The strange events of the afternoon completely forgotten, I opened the door. There, in the dim light of the hall, considerably the worse for wear, stood my little visitor of the afternoon. He was bare-headed, his dark curly locks plastered to his forehead with perspiration. His bowtie was missing and his checkered suit was covered with splotches of mud and some darker substance, especially around the left arm which he gingerly supported with his right hand.

"Mr. Rumplestein!"

He shook his head weakly and staggered into the room. "Not Rumplestein," he said, so low I could hardly hear him. "Tonight it's O'Grady." He collapsed on my leather chair, mumbling, "The door."

I bolted the door and hurried over to him. "What happened to your arm?"

"Never mind that now," he said stoically.

Despite his protests I carefully removed his jacket and cut away the sleeve of his shirt. There was an ugly wound on his arm. "How did this happen?" I asked, horrified.

"It's nothing," he said. Then he grinned momentarily. "The chap who caused it is feeling no pain at all!" He closed his eyes and his head began to sway. "If you have any liquor," he mumbled, "I feel faint, suddenly—"

I rummaged through my desk and found a tiny bottle of some cordial a colleague had once brought me as a jest, knowing I do not drink. While Mr. Rumplestein, or O'Grady, gulped down the liquid I inspected the wound. "A doctor should look at that," I said.

He shook his head and leaned back in the chair, the top of his head a good twelve inches below the top of the chair.

"I feel better now," he sighed.

"Then perhaps you will be good enough to tell me what this is all about." As I spoke I washed and dressed his wound as best I could. "You realize, my good fellow, for all I know you may be wanted by the police, in which case I could be arrested for harboring a criminal."

"I assure you, Professor Clarke, I am no criminal." He plucked a bit of mud from his beard and carefully deposited it on the table.

"But you've been wounded! And you infer you did some bodily harm to someone else."

He chuckled softly. "Bodily harm? I killed him!"

I recoiled in fright. "I must notify the police!"

"No! That would ruin everything! New York would be destroyed!!"

I clucked impatiently. "Please, Mr. Rumplestein, or O'Grady, or whatever your name is. If you cannot give me an honest answer, I shall be forced to call the authorities. This nonsense about—"

He held up his hand and emitted a huge sigh. "Very well," he said, "I will tell you what this is all about because my usefulness may come to an end abruptly and you may have to carry on. Listen carefully." I waited with mounting impatience.

"New York," he said after a brief pause, "is a huge, sprawling metropolis that breeds within itself the seeds of its own destruction. Transportation." I raised an eyebrow. "At best," he went on, "the traffic in Manhattan does not flow—it limps. Let one traffic light fail and vehicles are backed up for several blocks. True?"

I nodded. "Yes."

"Very well. Imagine, then, a situation where, at one given instant every single traffic light on this congested island turns green and STAYS green." I shuddered at the thought. "Picture the beauty of it," he said. "Not red, which would cause all automobiles to stop, but green, the signal to go! Imagine their mad desire to rush forward in righteous obedience to the law, and their awful frustration to find every other automobile and truck obeying the same law, regardless of the direction from which it is coming. It has been estimated by noted mathematicians who are involved in this plan, that within forty-five seconds all traffic in Manhattan would come to a standstill, it becoming impossible for a car to move forward or backward. Oh, what utter chaos!"

"Ab homine homini periculum quotidianum," I said.

"Eh?"

"Man is daily in danger from man. An ancient Roman said that."

"He knew what he was talking about. But this is only Phase One of the plan. A corollary is based upon the axiom that one disabled automobile is equal to ten thousand operating ones."

"I don't follow."

"The highways leading into and out of this island. Regardless of the number of lanes, if one automobile breaks down, traffic is immobilized for miles. Multiply that by several dozen, all at the same time, on all the entrances and exits to the island, and no earthly power could untangle that situation in less than a week, if then!"

His words evoked an image of metal monsters, stretched as far as the eye could see, steam pouring from their overheated radiators as they raucously bleated for help.

"All this can be accomplished quite simply and inexpensively," continued my bearded little man. "However, what of subsurface transportation?"

"You mean the subway system?"

"Exactly. Once again, simplicity is the key. What do subway riders use to gain entrance through the turnstiles? Tokens. Let us suppose that on this same given day the majority of tokens distributed are all fractionally larger than normal. Not enough to be noticed, mind you, but just enough so they cannot pass through the slots and activate the mechanism."

"But—"

"Do you realize the absolute ingenuity of this plan? Subway riders by the thousands will be trying to put tokens that they paid for into slots that will not receive them! The tremendous howl of anguish that will arise! The roar of frustration and then anger as the thousands pile upon the thousands at rush hour! The screaming and pushing as multitudes press forward at each subway station, demanding their rights of ingress as good citizens, while more multitudes press from the incoming trains demanding their rights of egress! Unquestionably the entire subway system will collapse in a matter of minutes! What was it you said before?"

"Ab homine homini periculum quotidianum?"

"And how!" He lit a cigar and puffed away for a few moments, filling my room with its foul odor. "Ingenious, eh?" he said finally.

"But to what end?" I asked. "If anarchy rules the city, how could whoever is behind this plan assume control?"

He leaned back in the chair, disappearing from view. "That is not part of the scheme. The purpose is to arouse the rest of the country to what has happened to its greatest metropolis. Every eye, ear, radio and television station will be turned towards Manhattan. The armed forces, all the resources of the government will, within hours, pour into the city, or try to. And at precisely that moment the rest of the country will be childishly open to invasion! If this plan succeeds, professor, the United States will be conquered within a matter of days, with remarkably little destruction or loss of life."

I stared at the little figure in the chair. Was he serious? More important—was he sane? "Who is planning this invasion?"

"Who else?"

"Why tell me this story? Why not go to the authorities?"

"I need sufficient proof, first. Unfortunately, matters are coming to a head far sooner than I expected. In addition, my disposing of one of their men earlier," he tapped his left arm significantly, "has left me in a vulnerable position. I dare not go to the authorities myself, for fear of exposing myself. And believe me"—he snapped his fingers—"I would not get as far as the nearest policeman. However, professor, you are unsuspected. You could report this plan with no danger to yourself."

"Enough! My dear Mr. Rumplestein-O'Grady, do you expect me to charge into a police station and blurt out this ridiculous story?"

"I don't expect you to charge anywhere, professor. Not without proof. I will get the proof for you, by tomorrow. Then—as I suspect—if I am unable to warn the authorities, I will expect you to do so. In the meantime, make use of these when you go to the university, tomorrow. I found them on the body of the man I disposed of."

He dropped several tinkly objects on my desk, rose, and, without another word, was gone. I picked up the items. They were subway tokens. I hurried to the window and glanced out. I could see the little man hurrying down the street, his head bobbing up and down like a swimmer in the ocean. Then, my mind in a turmoil, I turned out the light and went to bed. Fortunately, regardless of the press of circumstances, I have never had difficulty in falling asleep and tonight was no exception.

At seven-thirty the next morning I arose, dressed, and prepared my breakfast. I thought of the events of the preceding evening. Had it not been for the bloodied towel with which I had washed the little man's wounds, I might have dismissed the entire incident as a dream. I continued to think about it while walking to the subway. I berated myself for taking the story seriously even for a moment, as I dropped a token into the turnstile and pressed forward. I gasped in sudden pain as the turnstile, still locked, pushed into my midriff. I glanced at the token in the slot. It had not dropped. I pressed it down. It refused to budge. I tried several other tokens, all with the same result. By this time half a dozen people had gathered behind me, making angry remarks. Flustered, I backed away, bought a token from the cashier, and rode to the University. Then it was I recalled that I had tried to use the tokens my strange visitor had placed on my desk before parting from me, and which I had, without thinking, picked up in the morning.

All that day I pondered over the tokens and the odd tale of Mr. Rumplestein-O'Grady. I could still give it no credence, but I was disturbed. On my way home, that evening, as is my wont, I bought a newspaper and began reading it casually. Just before reaching my station, I came across a small item on one of the inside pages. It stated that a small, bearded man, wearing a checkered suit, had been found in the river that morning, stabbed. There were no identification papers on him, only a pocket full of subway tokens which, police believed, had been used to weight down the body.

"Good heavens!" I said aloud. Several passengers raised their eyebrows. I flushed, hurried out of the train and to my apartment where I fell into my chair, shocked and shaking. No doubt the body was that of Rumplestein. The poor little man! What did this mean? Could his story conceivably have been true?

The knock on my door startled me. "Professor, are you home?" It was my landlady. When I opened the door she handed me an envelope with my name written on it in small, neat letters. "A little fellow with a beard gave it to me early this morning, after you'd gone. He said to be sure you got it. Then he ran away." She shook her head in obvious disapproval of such actions.

After she left I tore open the envelope and read the contents.

"By the time you see this chances are excellent that I shall be dead. However, that is of little importance. I have found the proof we need—their distribution plant. It's an old warehouse. I am going there to see if I cannot obtain concrete proof—perhaps a pocketful of tokens. If I fail, you must carry on. Farewell, professor. It was a privilege knowing you."

Beneath the message was an address which I recognized as being in one of the less reputable sections of the city. There was no signature.

What to do! What to do! I no longer doubted the truth of little Mr. Rumplestein-O'Grady's story. But what to do about it? I considered going to the warehouse, but the thought of high adventure sends nothing but ennui coursing through my veins. Besides, there was undoubtedly some element of danger in that course. The police! Naturally! They would know how to deal with this situation and perhaps even avenge poor Mr. Rumplestein's death. Filled with righteous anger and indignation I hurried out and went to the nearest police station.

In retrospect I can understand the reaction of the desk sergeant to my wild-eyed claim that the city was in imminent danger of invasion and he must do something about it at once!

"How much, now, have ye had to drink?" he asked calmly.

When I swore that I was as sober as he, he grew purple with rage and threatened to have me thrown into jail for insulting a police officer unless I disappeared immediately.

All that night and the next day I tried to reach someone in authority with my information. The New York City police were admirably calm about my information. My actions and voice, however, seemed to disturb them greatly. When I insisted they investigate the warehouse, they told me the officer on the beat would do so in good time. When I suggested they examine the tokens found on the body they informed me that these had been turned over to the Property Clerk and if not claimed within ninety days would be given to the PAL.

As a last desperate measure I went to the New York office of the Federal Bureau of Investigation and presented myself to one of the Federal men. I told him my story. He looked at me calmly, then pored through a thick book on his desk. He closed one eye thoughtfully and peered at me through the other.

"There's really nothing," he said, "that we can do about it."

"Don't you believe me?"

"That has nothing to do with it. According to regulations this is strictly a municipal affair. It doesn't come within the jurisdiction of the FBI. And we wouldn't want to step on municipal toes." He closed the book smartly.

I was crushed. I couldn't believe it. Finally I said, "Serum est cavendi tempus in mediis malis!"

"What?"

"'It is too late to be cautious when in the very midst of dangers.' Seneca said that two thousand years ago."

The young man rose and nodded towards the door. "Good day, professor. And an E pluribus unum to you!"

That was an hour ago.

Professor Clarke stopped talking. Jimmy and I said nothing. The only sound was the hum of traffic outside. "And that is the way it is, gentlemen," said Professor Clarke, finally. "Quando cadet Roma, cadet et mundus. When Rome falls—the world!" He sipped the beer which by now had gone flat. "Do you believe me?"

Jimmy and I exchanged glances. "Have another beer," said Jimmy. "On the house."

"I see." Professor Clarke sighed. "Well, I cannot really blame you, gentlemen. I only hope you do not live to regret it." He got up and put a coin on the bar. Jimmy went to make change.

Then we became aware of automobile horns blasting steadily on a rising note of urgency. Jimmy and I ran outside. Traffic was piling up rapidly in the street. And as far as we could see in every direction, all the traffic lights had turned green!

"Holy cow!" said Jimmy. "He was telling the truth!"

"So it appears," said a voice at my elbow. I turned. It was the professor. There was a sad, wistful expression on his face. "Quod erat demonstrandum," he said softly. "Q.E.D." Then, as the horns got louder, and we could hear drivers cursing, he strode down the street and around the corner.

"Professor!" I yelled. "Wait!" I started to run after him when the horns stopped blowing. Cars started moving again, and many of the traffic lights had turned red.

Jimmy wiped his face in obvious relief. "Must have been a short circuit," he said hoarsely. "But for a minute—"

"Yes," I said. "A short circuit. Or maybe—a dry run to test facilities for the big day?"

Neither one of us said anything, but we both had the same thought as we returned to the bar. I picked up the subway token the professor had left there. I flipped it in the air several times and looked at Jimmy. He nodded in agreement. I went out and headed for the nearest subway.

Q.E.D.?