"Doctor," he said, as Kharkoff entered the room again, "do you suppose you could get some perfectly clean test-tubes and sterile bouillon from Miss Nevsky's laboratory? I think I saw a rack of tubes on the table."

"Surely," answered Kharkoff.

"You will excuse us, Mr. Kazanovitch," apologised Kennedy briskly, "but I feel that I am going to have a hard day to-morrow and - by the way, would you be so kind as to come up to my laboratory some time during the day, and continue your story."

On the way out Craig took the doctor aside for a moment, and they talked earnestly. At last Craig motioned to me.

"Walter," he explained, "Dr. Kharkoff is going to prepare some cultures in the test-tubes to-night so that I can make a microscopic examination of the blood of Saratovsky, Samarova, and later of his servant. The tubes will be ready early in the morning, and I have arranged with the doctor for you to call and get them if you have no objection."

I assented, and we started downstairs. As we passed a door on the second floor, a woman's voice called out, "Is that you, Boris?"

"No, Olga, this is Nicholas," replied the doctor. "It is Samarova," he said to us as he entered.

In a few moments he rejoined us. "She is no better," he continued, as we again started away. "I may as well tell you, Professor Kennedy, just how matters stand here. Samarova is head over heels in love with Kazanovitch - you heard her call for him just now? Before they left Paris, Kazanovitch showed some partiality for Olga, but now Nevsky has captured him. She is indeed a fascinating woman, but as for me, if Olga would consent to become Madame Kharkoff, it should be done to-morrow, and she need worry no longer over her broken contract with the American theatre managers. But women are not that way. She prefers the hopeless love. Ah, well, I shall let you know if anything new happens. Good-night, and a thousand thanks for your help, gentlemen."

Nothing was said by either of us on our journey uptown, for it was late and I, at least, was tired.

But Kennedy had no intention of going to bed, I found. Instead, he sat down in his easy chair and shaded his eyes, apparently in deep thought. As I stood by the table to fill my pipe for a last smoke, I saw that he was carefully regarding the letter he had picked up, turning it over and over, and apparently debating with himself what to do with it.

"Some kinds of paper can be steamed open without leaving any trace," he remarked in answer to my unspoken question, laying the letter down before me.

I read the address: "M. Alexander Alexandrovitch Orloff, - Rue de - , Paris, France."

"Letter-opening has been raised to a fine art by the secret service agents of foreign countries," he continued. "Why not take a chance? The simple operation of steaming a letter open is followed by reburnishing the flap with a bone instrument, and no trace is left. I can't do that, for this letter is sealed with wax. One way would be to take a matrix of the seal before breaking the wax and then replace a duplicate of it. No, I won't risk it. I'll try a scientific way."

Between two pieces of smooth wood, Craig laid the letter flat, so that the edges projected about a thirty-second of an inch. He flattened the projecting edge of the envelope, then roughened it, and finally slit it open.

"You see, Walter, later I will place the letter back, apply a hair line of strong white gum, and unite the edges of the envelope under pressure. Let us see what we have here."

He drew out what seemed to be a manuscript on very thin paper, and spread it out flat on the table before us. Apparently it was a scientific paper on a rather unusual subject, "Spontaneous Generation of Life." It was in longhand and read:

*Many thanks for the copy of the paper by Prof. Betallion of Dijon on the artificial fertilization of the eggs of frogs. I consider it a most important advance in the artificial generation of life. ___________

*In the printed book this is shown as handwritten ___________ =20

I will not attempt to reproduce in facsimile the entire manuscript, for it is unnecessary, and, in fact, I merely set down part of its contents here because it seemed so utterly valueless to me at the time. It went on to say:

While Betallion punctured the eggs with a platinum needle and developed them by means of electric discharges, Loeb in America placed eggs of the sea-urchin in a strong solution of sea water, then in a bath where they were subjected to the action of butyric acid. Finally they were placed in ordinary sea water again, where they developed in the natural manner. Delage at Roscorf used a liquid containing salts of magnesia and tannate of ammonia to produce the same result.

In his latest book on the Origin of Life Dr. Charlton Bastian tells of using two solutions. One consisted of two or three drops of dilute sodium silicate with eight drops of liquor fern pernitratis to one ounce of distilled water. The other was composed of the same amount of the silicate with six drops of dilute phosphoric acid and six grains of ammonium phosphate. He filled sterilised tubes, sealed them hermetically, and heated them to 125 or 145 degrees, Centigrade, although 60 or 70 degrees would have killed any bacteria remaining in them.

Next he exposed them to sunlight in a south window for from two to four months. When the tubes were opened Dr. Bastian found organisms in them which differed in no way from real bacteria. They grew and multiplied. He contends that he has proved the possibility of spontaneous generation of life.

Then there were the experiments of John Butler Burke of Cambridge, who claimed that he had developed "radiobes" in tubes of sterilised bouillon by means of radium emanations. Daniel Berthelot in France last year announced that he had used the ultra-violet rays to duplicate nature's own process of chlorophyll assimilation. He has broken up carbon dioxide and water-vapour in the air in precisely the same way that the green cells of plants do it.

Leduc at Nantes has made crystals grow from an artificial egg composed of certain chemicals. These crystals show all the apparent vital phenomena without being actually alive. His work is interesting, for it shows the physical forces that probably control minute life cells, once they are created.

"What do you make of it?" asked Kennedy, noting the puzzled look on my face as I finished reading.

"Well, recent research in the problem of the origin of life may be very interesting," I replied. "There are a good many chemicals mentioned here - I wonder if any of them is poisonous? But I am of the opinion that there is something more to this manuscript than a mere scientific paper."

"Exactly, Walter," said Kennedy in half raillery. "What I wanted to know was how you would suggest getting at that something."

Study as I might, I could make nothing out of it. Meanwhile Craig was busily figuring with a piece of paper and a pencil.

"I give it up, Craig," I said at last. "It is late. Perhaps we had better both turn in, and we may have some ideas on it in the morning."

For answer he merely shook his head and continued to scribble and figure on the paper. With a reluctant good-night I shut my door, determined to be up early in the morning and go for the tubes that Kharkoff was to prepare.

But in the morning Kennedy was gone. I dressed hastily, and was just about to go out when he hurried in, showing plainly the effects of having spent a sleepless night. He flung an early edition of a newspaper on the table.

"Too late," he exclaimed. "I tried to reach Kharkoff, but it was too late."

"Another East Side Bomb Outrage," I read. "While returning at a late hour last night from a patient, Dr. Nicholas Kharkoff, of - East Broadway, was severely injured by a bomb which had been placed in his hallway earlier in the evening. Dr. Kharkoff, who is a well-known physician on the East Side, states that he has been constantly shadowed by some one unknown for the past week or two. He attributes his escape with his life to the fact that since he was shadowed he has observed extreme caution. Yesterday his cook was poisoned and is now dangerously ill. Dr. Kharkoff stands high in the Russian community, and it is thought by the police that the bomb was placed by a Russian political agent, as Kharkoff has been active in the ranks of the revolutionists."

"But what made you anticipate it?" I asked of Kennedy, considerably mystified.

"The manuscript," he replied.

"The manuscript? How? Where is it?"

"After I found that it was too late to save Kharkoff and that he was well cared for at the hospital, I hurried to Saratovsky's. Kharkoff had fortunately left the tubes there, and I got them. Here they are. As for the manuscript in the letter, I was going to ask you to slip upstairs by some strategy and return it where I found it, when you went for the tubes this morning. Kazanovitch was out, and I have returned it myself, so you need not go, now."

"He's coming to see you to-day, isn't he?"

"I hope so. I left a note asking him to bring Miss Nevsky, if possible, too. Come, let us breakfast and go over to the laboratory. They may arrive at any moment. Besides, I'm interested to see what the tubes disclose."

Instead of Kazanovitch awaiting us at the laboratory, however, we found Miss Nevsky, haggard and worn. She was a tall, striking girl with more of the Gaul than the Slav in her appearance. There was a slightly sensuous curve to her mouth, but on the whole her face was striking and intellectual. I felt that if she chose she could fascinate a man so that he would dare anything. I never before understood why the Russian police feared the women revolutionists so much. It was because they were themselves, plus every man they could influence.

Nevsky appeared very excited. She talked rapidly, and fire flashed from her grey eyes. "They tell me at the club," she began, " that you are investigating the terrible things that are happening to us. Oh, Professor Kennedy, it is awful! Last night I was staying with some friends on East Broadway. Suddenly we heard a terrific explosion up the street. It was in front of Dr. Kharkoff's house. Thank Heaven, he is still alive! But I was so unnerved I could not sleep. I fancied I might be the next to go.

"Early this morning I hastened to return to Fifth Avenue. As I entered the door of my room I could not help thinking of the horrible fate of Dr. Kharkoff. For some unknown reason, just as I was about to push the door farther open, I hesitated and looked - I almost fainted. There stood another bomb just inside. If I had moved the door a fraction of an inch it would have exploded. I screamed, and Olga, sick as she was, ran to my assistance - or perhaps she thought something had happened to Boris. It is standing there yet. None of us dares touch it. Oh, Professor Kennedy, it is dreadful, dreadful. And I cannot find Boris - Mr. Kazanovitch, I mean. Saratovsky, who is like a father to us all, is scarcely able to speak. Dr. Kharkoff is helpless in the hospital. Oh, what are we to do, what are we to do?"

She stood trembling before us, imploring.

"Calm yourself, Miss Nevsky," said Kennedy in a reassuring tone. "Sit down and let us plan. I take it that it was a chemical bomb and not one with a fuse, or you would have a different story to tell. First of all, we must remove it. That is easily done."

He called up a near-by garage and ordered an automobile. "I will drive it myself," he ordered, "only send a man around with it immediately."

"No, no, no," she cried, running toward him, you must not risk it. It is bad enough that we should risk our lives. But strangers must not. Think, Professor Kennedy. Suppose the bomb should explode at a touch! Had we not better call the police and let them take the risk, even if it does get into the papers?"

"No," replied Kennedy firmly. "Miss Nevsky, I am quite willing to take the risk. Besides, here comes the automobile."

"You are too kind," she exclaimed. "Kazanovitch himself could do no more. How am I ever to thank you?"

On the back of the automobile Kennedy placed a peculiar oblong box, swung on two concentric rings balanced on pivots, like a most delicate compass.

We rode quickly downtown, and Kennedy hurried into the house, bidding us stand back. With a long pair of tongs he seized the bomb firmly. It was a tense moment. Suppose his hand should unnecessarily tremble, or he should tip it just a bit - it might explode and blow him to atoms. Keeping it perfectly horizontal he carried it carefully out to the waiting automobile and placed it gingerly in the box.

"Wouldn't it be a good thing to fill the box with water?" I suggested, having read somewhere that that was the usual way of opening a bomb, under water.

"No," he replied, as he closed the lid, "that wouldn't do any good with a bomb of this sort. It would explode under water just as well as in air. This is a safety bomb-carrier. It is known as the Cardon suspension. It was invented by Professor Cardono, an Italian. You see, it is always held in a perfectly horizontal position, no matter how you jar it. I am now going to take the bomb to some safe and convenient place where I can examine it at my leisure. Meanwhile, Miss Nevsky, I will leave you in charge of Mr. Jameson."

"Thank you so much," she said. "I feel better now. I didn't dare go into my own room with that bomb at the door. If Mr. Jameson can only find out what has become of Mr. Kazanovitch, that is all I want. What do you suppose has happened to him? Is he, too, hurt or ill?"

"Very well, then," Craig replied. " I will commission you, Walter, to find Kazanovitch. I shall be back again shortly before noon to examine the wreck of Kharkoff's office. Meet me there. Goodbye, Miss Nevsky."

It was not the first time that I had had a roving commission to find some one who had disappeared in New York. I started by inquiring for every possible place that he might be found. No one at the Fifth Avenue house could tell me anything definite, though they were able to give me a number of places where he was known. I consumed practically the whole morning going from one place to another on the East Side. Some of the picturesque haunts of the revolutionists would have furnished material for a story in themselves. But nowhere had they any word of Kazanovitch, until I visited a Polish artist who was illustrating his stories. He had been there, looking very worn and tired, and had talked vacantly about the sketches which the artist had showed him. After that I lost all trace of him again. It was nearly noon as I hurried to meet Craig at Kharkoff's.

Imagine my surprise to see Kazanovitch already there, seated in the wrecked office, furiously smoking cigarettes and showing evident signs of having something very disturbing on his mind. The moment he caught sight of me, he hurried forward.

"Is Professor Kennedy coming soon?" he inquired eagerly. "I was going up to his laboratory, but I called up Nevsky, and she said he would be here at noon." Then he put his hand up to my ear and whispered, "I have found out who it was who shadowed Kharkoff."

"Who?" I asked, saying nothing of my long search of the morning.

"His name is Revalenko - Feodor Revalenko. I saw him standing across the street in front of the house last night after you had gone. When Kharkoff left, he followed him. I hurried out quietly and followed both of them. Then the explosion came. This man slipped down a narrow street as soon as he saw Kharkoff fall. As people were running to Kharkoff's assistance, I did the same. He saw me following him and ran, and I ran, too, and overtook him. Mr. Jameson, when I looked into his face I could not believe it. Revalenko - he is one of the most ardent members of our organisation. He would not tell me why he had followed Kharkoff. I could make him confess nothing. But I am sure he is an agent provocateur of the Russian government, that he is secretly giving away the plans that we are making, everything. We have a plot on now - perhaps he has informed them of that. Of course he denied setting the bomb or trying to poison any of us, but he was very frightened. I shall denounce him at the first opportunity."

I said nothing. Kazanovitch regarded me keenly to see what impression the story made on me, but I did not let my looks betray anything, except proper surprise, and he seemed satisfied.

It might be true, after all, I reasoned, the more I thought of it. I had heard that the Russian consul-general had a very extensive spy system in the city. In fact, even that morning I had had pointed out to me some spies at work in the public libraries, watching what young Russians were reading. I did not doubt that there were spies in the very inner circle of the revolutionists themselves.

At last Kennedy appeared. While Kazanovitch poured forth his story, with here and there, I fancied, an elaboration of a particularly dramatic point, Kennedy quickly examined the walls and floor of the wrecked office with his magnifying-glass. When he had concluded his search, he turned to Kazanovitch.

"Would it be possible," he asked, "to let this Revalenko believe that he could trust you, that it would be safe for him to visit you to-night at Saratovsky's? Surely you can find some way of reassuring him."

"Yes, I think that can be arranged," said Kazanovitch. "I will go to him, will make him think I have misunderstood him, that I have not lost faith in him, provided he can explain all. He will come. Trust me."

"Very well, then. To-night at eight I shall be there," promised Kennedy, as the novelist and he shook hands.

"What do you think of the Revalenko story?" I asked of Craig, as we started uptown again.

"Anything is possible in this case," he answered sententiously.

"Well," I exclaimed, "this all is truly Russian. For intrigue they are certainly the leaders of the world to-day. There is only one person that I have any real confidence in, and that is old Saratovsky himself. Somebody is playing traitor, Craig. Who is it?"

"That is what science will tell us to-night," was his brief reply. There was no getting anything out of Craig until he was absolutely sure that his proofs had piled up irresistibly.

Promptly at eight we met at the old house on Fifth Avenue. Kharkoff's wounds had proved less severe than had at first been suspected, and, having recovered from the shock, he insisted on being transferred from the hospital in a private ambulance so that he could be near his friends. Saratovsky, in spite of his high fever, ordered that the door to his room be left open and his bed moved so that he could hear and see what passed in the room down the hall. Nevsky was there and Kazanovitch, and even brave Olga Samarova, her pretty face burning with the fever, would not be content until she was carried upstairs, although Dr. Kharkoff protested vigorously that it might have fatal consequences. Revalenko, an enigma of a man, sat stolidly. The only thing I noticed about him was an occasional look of malignity at Nevsky and Kazanovitch when he thought he was unobserved.

It was indeed a strange gathering, the like of which the old house had never before harboured in all its varied history. Every one was on the qui vive, as Kennedy placed on the table a small wire basket containing some test-tubes, each tube corked with a small wadding of cotton. There was also a receptacle holding a dozen glass-handled platinum wires, a microscope, and a number of slides. The bomb, now rendered innocuous by having been crushed in a huge hydraulic press, lay in fragments in the box.

"First, I want you to consider the evidence of the bomb," began Kennedy. "No crime, I firmly believe, is ever perpetrated without leaving some clue. The slightest trace, even a drop of blood no larger than a pin-head, may suffice to convict a murderer. The impression made on a cartridge by the hammer of a pistol, or a single hair found on the clothing of a suspected person, may serve as valid proof of crime.

"Until lately, however, science was powerless against the bomb-thrower. A bomb explodes into a thousand parts, and its contents suddenly become gaseous. You can't collect and investigate the gases. Still, the bomb-thrower is sadly deceived if he believes the bomb leaves no trace for the scientific detective. It is difficult for the chemist to find out the secrets of a shattered bomb. But it can be done.

"I examined the walls of Dr. Kharkoff's house, and fortunately was able to pick out a few small fragments of the contents of the bomb which had been thrown out before the flame ignited them. I have analysed them, and find them to be a peculiar species of blasting-gelatine. It is made at only one factory in this country, and I have a list of purchasers for some time back. One name, or rather the description of an assumed name, in the list agrees with other evidence I have been able to collect. Moreover, the explosive was placed in a lead tube. Lead tubes are common enough. However, there is no need of further evidence."

He paused, and the revolutionists stared fixedly at the fragments of the now harmless bomb before them.

"The exploded bomb," concluded Craig, "was composed of the same materials as this, which I found unexploded at the door of Miss Nevsky's room - the same sort of lead tube, the same blasting-gelatine. The fuse, a long cord saturated in sulphur, was merely a blind. The real method of explosion was by means of a chemical contained in a glass tube which was inserted after the bomb was put in place. The least jar, such as opening a door, which would tip the bomb ever so little out of the horizontal, was all that was necessary to explode it. The exploded bomb and the unexploded were in all respects identical - the same hand set both."

A gasp of astonishment ran through the circle. Could it be that one of their own number was playing false? In at least this instance in the warfare of the chemist and the dynamiter the chemist had come out ahead.

"But," Kennedy hurried along, "the thing that interests me most about this case is not the evidence of the bombs. Bombs are common enough weapons, after all. It is the evidence of almost diabolical cunning that has been shown in the effort to get rid of the father of the revolution, as you like to call him."

Craig cleared his throat and played with our feelings as a cat does with a mouse. "Strange to say, the most deadly, the most insidious, the most elusive agency for committing murder is one that can be obtained and distributed with practically no legal restrictions. Any doctor can purchase disease germs in quantities sufficient to cause thousands and thousands of deaths without giving any adequate explanation for what purpose he requires them. More than that, any person claiming to be a scientist or having some acquaintance with science and scientists can usually obtain germs without difficulty. Every pathological laboratory contains stores of disease germs, neatly sealed up in test-tubes, sufficient to depopulate whole cities and even nations. With almost no effort, I myself have actually cultivated enough germs to kill every person within a radius of a mile of the Washington Arch down the street. They are here in these test-tubes."

We scarcely breathed. Suppose Kennedy should let loose this deadly foe, these germs of death, whatever they were? Yet that was precisely what some fiend incarnate had done, and that fiend was sitting in the room with us.

"Here I have one of the most modern dark-field microscopes," he resumed. "On this slide I have placed a little pin-point of a culture made from the blood of Saratovsky. I will stain the culture. Now - er - Walter, look through the microscope under this powerful light and tell us what you see on the slide."

I bent over. "In the darkened field I see a number of germs like dancing points of coloured light," I said. "They are wriggling about with a peculiar twisting motion."

"Like a corkscrew," interrupted Kennedy, impatient to go on. "They are of the species known as Spirilla. Here is another slide, a culture from the blood of Samarova."

"I see them there, too," I exclaimed.

Every one was now crowding about for a glimpse, as I raised my head.

"What is this germ?" asked a hollow voice from the doorway.

We looked, startled. There stood Saratovsky, more like a ghost than a living being. Kennedy sprang forward and caught him as he swayed, and I moved up an armchair for him.

It is the spirillum Obermeieri," said Kennedy, "the germ of the relapsing fever, but of the most virulent Asiatic strain. Obermeyer, who discovered it, caught the disease and died of it, a martyr to science."

A shriek of consternation rang forth from Samarova. The rest of us paled, but repressed our feelings.

One moment," added Kennedy hastily. "Don't be unnecessarily alarmed. I have something more to say. Be calm for a moment longer."

He unrolled a blue-print and placed it on the table.

"This," he continued, "is the photographic copy of a message which, I suppose, is now on its way to the Russian minister to France in Paris. Some one in this room besides Mr. Jameson and myself has seen this letter before. I will hold it up as I pass around and let each one see it.

In intense silence Kennedy passed before each of us, holding up the blue-print and searchingly scanning the faces. No one betrayed by any sign that he recognised it. At last it came to Revalenko himself.

"The checkerboard, the checkerboard!" he cried, his eyes half starting from their sockets as he gazed at it.

"Yes," said Kennedy in a low tone, "the checkerboard. It took me some time to figure it out. It is a cipher that would have baffled Poe. In fact, there is no means of deciphering it unless you chance to know its secret. I happened to have heard of it a long time ago abroad, yet my recollection was vague, and I had to reconstruct it with much difficulty. It took me all night to do it. It is a cipher, however, that is well known among the official classes of Russia.

"Fortunately I remember the crucial point, without which I should still be puzzling over it. It is that a perfectly innocent message, on its face, may be used to carry a secret, hidden message. The letters which compose the words, instead of being written continuously along, as we ordinarily write, have, as you will observe if you look twice, breaks, here and there. These breaks in the letters stand for numbers.

"Thus the first words are 'Many thanks.' The first break is at the end of the letter 'n,' between it and the 'y.' There are three letters before this break. That stands for the number 3.

"When you come to the end of a word, if the stroke is down at the end of the last letter, that means no break; if it is up, it means a break. The stroke at the end of the 'y' is plainly down. Therefore there is no break until after the 't.' That gives us the number 2. So we get 1 next, and again 1, and still again 1; then 5; then 5; then 1; and so on.

"Now, take these numbers in pairs, thus 3 - 2; 1 - 1; 1 - 5; 5 - 1. By consulting this table you can arrive at the hidden message.

He held up a cardboard bearing the following arrangement of the letters of the alphabet: _______ __1__2__3__4__5_ _1__A__B__C__D__E_ _2__F__G__H__IJ_K_ _3__L__M__N__O__P_ _4__Q__R__S__T__U_ _5__V__W__X__Y__Z_

"Thus," he continued, "3 - 2 means the third column and second line. That is 'H.' Then 1 - 1 is 'A'; 1 - 5 is 'V'; 5 - 1 is 'E' - and we get the word 'Have.'"

Not a soul stirred as Kennedy unfolded the cipher. What was the terrible secret in that scientific essay I had puzzled so unsuccessfully over, the night before?

"Even this can be complicated by choosing a series of fixed numbers to be added to the real numbers over and over again, Or the order of the alphabet can be changed. However, we have the straight cipher only to deal with here."

"And what for Heaven's sake does it reveal?" asked Saratovsky, leaning forward, forgetful of the fever that was consuming him.

Kennedy pulled out a piece of paper on which he had written the hidden message and read:

"Have successfully inoculated S. with fever. Public opinion America would condemn violence. Think best death should appear natural. Samarova infected also. Cook unfortunately took dose in food intended Kharkoff. Now have three cases. Shall stop there at present. Dangerous excite further suspicion health authorities."

Rapidly I eliminated in my mind the persons mentioned, as Craig read. Saratovsky of course was not guilty, for the plot had centred about him. Nor was little Samarova, nor Dr. Kharkoff. I noted Revalenko and Kazanovitch glaring at each other and hastily tried to decide which I more strongly suspected.

"Will get K.," continued Kennedy. "Think bomb perhaps all right. K. case different from S. No public sentiment."

"So Kharkoff had been marked for slaughter," I thought. Or was "K." Kazanovitch? I regarded Revalenko more closely. He was suspiciously sullen.

"Must have more money. Cable ten thousand rubles at once Russian consul-general. Will advise you plot against Czar as details perfected here. Expect break up New York band with death of S."

If Kennedy himself had thrown a bomb or scattered broadcast the contents of the test-tubes, the effect could not have been more startling than his last quiet sentence - and sentence it was in two senses.

"Signed," he said, folding the paper up deliberately, "Ekaterina Nevsky."

It was as if a cable had snapped and a weight had fallen. Revalenko sprang up and grasped Kazanovitch by the hand. "Forgive me, comrade, for ever suspecting you," he cried.

"And forgive me for suspecting you," replied Kazanovitch, "but how did you come to shadow Kharkoff?"

"I ordered him to follow Kharkoff secretly and protect him," explained Saratovsky.

Olga and Ekaterina faced each other fiercely. Olga was trembling with emotion. Nevsky stood coldly, defiantly. If ever there was a consummate actress it was she, who had put the bomb at her own door and had rushed off to start Kennedy on a blind trail.

"You traitress," cried Olga passionately, forgetting all in her outraged love. "You won his affections from me by your false beauty - yet all the time you would have killed him like a dog for the Czar's gold. At last you are unmasked - you Azeff in skirts. False friend - you would have killed us all - Saratovsky, Kharkoff

"Be still, little fool," exclaimed Nevsky contemptuously. "The spirilla fever has affected your brains. Bah! I will not stay with those who are so ready to suspect an old comrade on the mere word of a charlatan. Boris Kazanovitch, do you stand there silent and let this insult be heaped upon me?"

For answer, Kazanovitch deliberately turned his back on his lover of a moment ago and crossed the room. "Olga," he pleaded, "I have been a fool. Some day I may be worthy of your love. Fever or not, I must beg your forgiveness."

With a cry of delight the actress flung her arms about Boris, as he imprinted a penitent kiss on her warm lips.

"Simpleton," hissed Nevsky with curling lips. "Now you, too, will die."

"One moment, Ekaterina Nevsky," interposed Kennedy, as he picked up some vacuum tubes full of a golden-yellow powder, that lay on the table. "The spirilla, as scientists now know, belong to the same family as those which cause what we call, euphemistically, the 'black plague.' It is the same species as that of the African sleeping sickness and the Philippine yaws. Last year a famous doctor whose photograph I see in the next room, Dr. Ehrlich of Frankfort, discovered a cure for all these diseases. It will rid the blood of your victims of the Asiatic relapsing fever germs in forty-eight hours. In these tubes I have the now famous salvarsan."

With a piercing shriek of rage at seeing her deadly work so quickly and completely undone, Nevsky flung herself into the little laboratory behind her and bolted the door.

Her face still wore the same cold, contemptuous smile, as Kennedy gently withdrew a sharp scalpel from her breast.

"Perhaps it is best this way, after all," he said simply.



IV

THE FIREBUG

A big, powerful, red touring-car, with a shining brass bell on the front of it, was standing at the curb before our apartment late one afternoon as I entered. It was such a machine as one frequently sees threading its reckless course in and out among the trucks and street-cars, breaking all rules and regulations, stopping at nothing, the bell clanging with excitement, policemen holding back traffic instead of trying to arrest the driver - in other words, a Fire Department automobile.

I regarded it curiously for a moment, for everything connected with modern fire-fighting is interesting. Then I forgot about it as I was whisked up in the elevator, only to have it recalled sharply by the sight of a strongly built, grizzled man in a blue uniform with red lining. He was leaning forward, earnestly pouring forth a story into Kennedy's ear.

"And back of the whole thing, sir," I heard him say as he brought his large fist down on the table, "is a firebug - mark my words."

Before I could close the door, Craig caught my eye, and I read in his look that he had a new case - one that interested him greatly. "Walter," he cried, "this is Fire Marshal McCormick. It's all right, McCormick. Mr. Jameson is an accessory both before and after the fact in my detective cases."

A firebug! - one of the most dangerous of criminals. The word excited my imagination at once, for the newspapers had lately been making much of the strange and appalling succession of apparently incendiary fires that had terrorised the business section of the city.

"Just what makes you think that there is a firebug - one firebug, I mean - back of this curious epidemic of fires?" asked Kennedy, leaning back in his morris-chair with his finger-tips together and his eyes half closed as if expecting a revelation from some subconscious train of thought while the fire marshal presented his case.

"Well, usually there is no rhyme or reason about the firebug," replied McCormick, measuring his words, "but this time I think there is some method in his madness. You know the Stacey department-stores and their allied dry-goods and garment-trade interests?

Craig nodded. Of course we knew of the gigantic dry-goods combination. It had been the talk of the press at the time of its formation, a few months ago, especially as it included among its organisers one very clever business woman, Miss Rebecca Wend. There had been considerable opposition to the combination in the trade, but Stacey had shattered it by the sheer force of his personality. McCormick leaned forward and, shaking his forefinger to emphasise his point, replied slowly, "Practically every one of these fires has been directed against a Stacey subsidiary or a corporation controlled by them."

"But if it has gone as far as that," put in Kennedy, "surely the regular police ought to be of more assistance to you than I."

"I have called in the police," answered McCormick wearily, "but they haven't even made up their minds whether it is a single firebug or a gang. And in the meantime, my God, Kennedy, the firebug may start a fire that will get beyond control!"

"You say the police haven't a single clue to any one who might be responsible for the fires?" I asked, hoping that perhaps the marshal might talk more freely of his suspicions to us than he had already expressed himself in the newspaper interviews I had read.

"Absolutely not a clue - except such as are ridiculous," replied McCormick, twisting his cap viciously.

No one spoke. We were waiting for McCormick to go on.

"The first fire," he began, repeating his story for my benefit, although Craig listened quite as attentively as if he had not heard it already, "was at the big store of Jones, Green & Co., the clothiers. The place was heavily insured. Warren, the manager and real head of the firm, was out of town at the time."

The marshal paused as if to check off the strange facts in his mind as he went along.

"The next day another puzzling fire occurred. It was at the Quadrangle Cloak and Suit Co., on Fifth Avenue. There had been some trouble, I believe, with the employees, and the company had discharged a number of them. Several of the leaders have been arrested, but I can't say we have anything against any of them. Still, Max Bloom, the manager of this company, insists that the fire was set for revenge, and indeed it looks as much like a fire for revenge as the Jones-Green fire does" - here he lowered his voice confidentially - "for the purpose of collecting insurance.

"Then came the fire in the Slawson Building, a new loft-building that had been erected just off Fourth Avenue. Other than the fact that the Stacey interests put up the money for financing this building there seemed to be no reason for that fire at all. The building was reputed to be earning a good return on the investment, and I was at a loss to account for the fire. I have made no arrests for it - just set it down as the work of a pure pyromaniac, a man who burns buildings for fun, a man with an inordinate desire to hear the fire-engines screech through the streets and perhaps get a chance to show a little heroism in 'rescuing' tenants. However, the adjuster for the insurance company, Lazard, and the adjuster for the insured, Hartstein, have reached an agreement, and I believe the insurance is to be paid."

"But," interposed Kennedy, "I see no evidence of organised arson so far."

"Wait," replied the fire marshal. "That was only the beginning, you understand. A little later came a fire that looked quite like an attempt to mask a robbery by burning the building afterward. That was in a silk-house near Spring Street. But after a controversy the adjusters have reached an agreement on that case. I mention these fires because they show practically all the types of work of the various kinds of firebug - insurance, revenge, robbery, and plain insanity. But since the Spring Street fire, the character of the fires has been more uniform. They have all been in business places, or nearly all."

Here the fire marshal launched forth into a catalogue of fires of suspected incendiary origin, at least eight in all. I took them down hastily, intending to use the list some time in a box head with an article in the Star. When he had finished his list I hastily counted up the number of killed. There were six, two of them firemen, and four employees. The money loss ranged into the millions.

McCormick passed his hand over his forehead to brush off the perspiration. "I guess this thing has got on my nerves," he muttered hoarsely. " Everywhere I go they talk about nothing else. If I drop into the restaurant for lunch, my waiter talks of it. If I meet a newspaper man, he talks of it. My barber talks of it - everybody. Sometimes I dream of it; other times I lie awake thinking about it. I tell you, gentlemen, I've sweated blood over this problem."

"But," insisted Kennedy, "I still can't see why you link all these fires as due to one firebug. I admit there is an epidemic of fires. But what makes you so positive that it is all the work of one man?"

"I was coming to that. For one thing, he isn't like the usual firebug at all. Ordinarily they start their fires with excelsior and petroleum, or they smear the wood with paraffin or they use gasoline, benzine, or something of that sort. This fellow apparently scorns such crude methods. I can't say how he starts his fires, but in every case I have mentioned we have found the remains of a wire. It has something to do with electricity - but what, I don't know. That's one reason why I think these fires are all connected. Here's another."

McCormick pulled a dirty note out of his pocket and laid it on the table. We read it eagerly:

Hello, Chief! Haven't found the firebug yet, have you? You will know who he is only when I am dead and the fires stop. I don't suppose you even realise that the firebug talks with you almost every day about catching the firebug. That's me. I am the real firebug, that is writing this letter. I am going to tell you why I am starting these fires. There's money in it - an easy living. They never caught me in or anywhere, so you might as well quit looking for me and take your medicine.

A. SPARK.

"Humph!" ejaculated Kennedy, "he has a sense of humour, anyhow - A. Spark!"

"Queer sense of humour," growled McCormick, gritting his teeth. "Here's another I got to-day:

Say, Chief: We are going to get busy again and fire a big department-store next. How does that suit Your Majesty? till the fun begins when the firebug gets to work again.

A. SPARK.

"Well, sir, when I got that letter," cried McCormick, "I was almost ready to ring in a double-nine alarm at once - they have me that bluffed out. But I said to myself, 'There's only one thing to do - see this man Kennedy.' So here I am. You see what I am driving at? I believe that firebug is an artist at the thing, does it for the mere fun of it and the ready money in it. But more than that, there must be some one back of him. Who is the man higher up - we must catch him. See?"

"A big department-store," mused Kennedy.

"That's definite - there are only a score or so of them, and the Stacey interests control several. Mac, I'll tell you what I'll do. Let me sit up with you to-night at headquarters until we get an alarm. By George, I'll see this case through to a finish!

The fire marshal leaped to his feet and bounded over to where Kennedy was seated. With one hand on Craig's shoulder and the other grasping Craig's hand, he started to speak, but his voice choked.

"Thanks," he blurted out huskily at last. "My reputation in the department is at stake, my promotion, my position itself, my - my family - er - er - "

"Not a word, sir," said Kennedy, his features working sympathetically. "To-night at eight I will go on watch with you. By the way, leave me those A. Spark notes."

McCormick had so far regained his composure as to say a hearty farewell. He left the room as if ten years had been lifted off his shoulders. A moment later he stuck his head in the door again. "I'll have one of the Department machines call for you, gentlemen," he said.

After the marshal had gone, we sat for several minutes in silence. Kennedy was reading and rereading the notes, scowling to himself as if they presented a particularly perplexing problem. I said nothing, though my mind was teeming with speculations. At length he placed the notes very decisively on the table and snapped out the remark,

"Yes, it must be so."

"What?" I queried, still drumming away at my typewriter, copying the list of incendiary fires against the moment when the case should be complete and the story released for publication, as it were.

"This note," he explained, picking up the first one and speaking slowly, "was written by a woman."

I swung around in my chair quickly. "Get out!" I exclaimed sceptically. "No woman ever used such phrases.

"I didn't say composed by a woman - I said written by a woman," he replied.

"Oh," I said, rather chagrined.

"It is possible to determine sex from handwriting in perhaps eighty cases out of a hundred," Kennedy went on, enjoying my discomfiture. "Once I examined several hundred specimens of writing to decide that point to my satisfaction. Just to test my conclusions I submitted the specimens to two professional graphologists. I found that our results were slightly different, but I averaged the thing up to four cases out of five correct. The so-called sex signs are found to be largely influenced by the amount of writing done, by age, and to a certain extent by practice and professional requirements, as in the conventional writing of teachers and the rapid hand of bookkeepers. Now in this case the person who wrote the first note was only an indifferent writer. Therefore the sex signs are pretty likely to be accurate. Yes, I'm ready to go on the stand and swear that this note was written by a woman and the second by a man."

"Then there's a woman in the case, and she wrote the first note for the firebug - is that what you mean?" I asked.

"Exactly. There nearly always is a woman in the case, somehow or other. This woman is closely connected with the firebug. As for the firebug, whoever it may be, he performs his crimes with cold premeditation and, as De Quincey said, in a spirit of pure artistry. The lust of fire propels him, and he uses his art to secure wealth. The man may be a tool in the hands of others, however. It's unsafe to generalise on the meagre facts we now have. Oh, well, there is nothing we can do just yet. Let's take a walk, get an early dinner, and be back here before the automobile arrives."

Not a word more did Kennedy say about the case during our stroll or even on the way downtown to fire headquarters.

We found McCormick anxiously waiting for us. High up in the sandstone tower at headquarters, we sat with him in the maze of delicate machinery with which the fire game is played in New York. In great glass cases were glistening brass and nickel machines with discs and levers and bells, tickers, sheets of paper, and annunciators without number. This was the fire-alarm telegraph, the "roulette-wheel of the fire demon," as some one has aptly called it.

"All the alarms for fire from all the boroughs, both from the regular alarm-boxes and the auxiliary systems, come here first over the network of three thousand miles or more of wire nerves that stretch out through the city," McCormick was explaining to us.

A buzzer hissed.

"Here's an alarm now," he exclaimed, all attention.

"Three," "six," "seven," the numbers appeared on the annunciator. The clerks in the office moved as if they were part of the mechanism. Twice the alarm was repeated, being sent out all over the city. McCormick relapsed from his air of attention.

"That alarm was not in the shopping district," he explained, much relieved. "Now the fire-houses in the particular district where that fire is=20have received the alarm instantly. Four engines, two hook-and-ladders, a water-tower, the battalion chief, and a deputy are hurrying to that fire. Hello, here comes another."

Again the buzzer sounded. "One," "four," "five" showed in the annunciator.

Even before the clerks could respond, McCormick had dragged us to the door. In another instant we were wildly speeding uptown, the bell on the front of the automobile clanging like a fire-engine, the siren horn going continuously, the engine of the machine throbbing with energy until the water boiled in the radiator.

"Let her out, Frank," called McCormick to his chauffeur, as we rounded into a broad and now almost deserted thoroughfare.

Like a red streak in the night we flew up that avenue, turned into Fourteenth Street on two wheels, and at last were on Sixth Avenue. With a jerk and a skid we stopped. There were the engines, the hose-carts, the hook-and-ladders, the salvage corps, the police establishing fire lines-everything. But where was the fire?

The crowd indicated where it ought to be - it was Stacey's. Firemen and policemen were entering the huge building. McCormick shouldered in after them, and we followed.

"Who turned in the alarm?" he asked as we mounted the stairs with the others.

"I did," replied a night watchman on the third landing. "Saw a light in the office on the third floor back - something blazing. But it seems to be out now."

We had at last come to the office. It was dark and deserted, yet with the lanterns we could see the floor of the largest room littered with torn books and ledgers.

Kennedy caught his foot in something. It was a loose wire on the floor. He followed it. It led to an electric-light socket, where it was attached.

"Can't you turn on the lights?" shouted McCormick to the watchman.

"Not here. They're turned on from downstairs, and they're off for the night. I'll go down if you want me to and -"

"No," roared Kennedy. "Stay where you are until I follow the wire to the other end."

At last we came to a little office partitioned off from the main room. Kennedy carefully opened the door. One whiff of the air from it was sufficient. He banged the door shut again.

"Stand back with those lanterns, boys," he ordered.

I sniffed, expecting to smell illuminating-gas. Instead, a peculiar, sweetish odour pervaded the air. For a moment it made me think of a hospital operating-room.

"Ether," exclaimed Kennedy. "Stand back farther with those lights and hold them up from the floor."

For a moment he seemed to hesitate as if at loss what to do next. Should he open the door and let this highly inflammable gas out or should he wait patiently until the natural ventilation of the little office had dispelled it?

While he was debating he happened to glance out of the window and catch sight of a drug-store across the street.

"Walter," he said to me, "hurry across there and get all the saltpeter and sulphur the man has in the shop.

I lost no time in doing so. Kennedy dumped the two chemicals into a pan in the middle of the main office, about three-fifths saltpeter and two-fifths sulphur, I should say. Then he lighted it. The mass burned with a bright flame but without explosion. We could smell the suffocating fumes from it, and we retreated. For a moment or two we watched it curiously at a distance.

"That's very good extinguishing-powder," explained Craig as we sniffed at the odour. "It yields a large amount of carbon dioxide and sulphur dioxide. Now - before it gets any worse - I guess it's safe to open the door and let the ether out. You see this is as good a way as any to render safe a room full of inflammable vapour. Come, we'll wait outside the main office for a few minutes until the gases mix.

It seemed hours before Kennedy deemed it safe to enter the office again with a light. When we did so, we made a rush for the little cubby-hole of an office at the other end. On the floor was a little can of ether, evaporated of course, and beside it a small apparatus apparently used for producing electric sparks.

"So, that's how he does it," mused Kennedy, fingering the can contemplatively. "He lets the ether evaporate in a room for a while and then causes an explosion from a safe distance with this little electric spark. There's where your wire comes in, McCormick. Say, my man, you can switch on the lights from downstairs, now."

As we waited for the watchman to turn on the lights I exclaimed, "He failed this time because the electricity was shut off."

Precisely, Walter," assented Kennedy.

"But the flames which the night watchman saw, what of them?" put in McCormick, considerably mystified. "He must have seen something."

Just then the lights winked up.

"Oh, that was before the fellow tried to touch off the ether vapour," explained Kennedy. "He had to make sure of his work of destruction first - and, judging by the charred papers about, he did it well. See, he tore leaves from the ledgers and lighted them on the floor. There was an object in all that. What was it? Hello! Look at this mass of charred paper in the corner."

He bent down and examined it carefully. "Memoranda of some kind, I guess. I'll save this burnt paper and look it over later. Don't disturb it. I'll take it away myself."

Search as we might, we could find no other trace of the firebug, and at last we left. Kennedy carried the charred paper carefully in a large hat-box.

"There'll be no more fires to-night, McCormick," he said. "But I'll watch with you every night until we get this incendiary. Meanwhile I'll see what I can decipher, if anything, in this burnt paper."

Next day McCormick dropped in to see us again. This time he had another note, a disguised scrawl which read:

Chief I'm not through. Watch me get another store yet. I won't fall down this time. Craig scowled as he read the note and handed it to me. "The man's

A. SPARK.

writing this time - like the second note," was all he said. "McCormick, since we know where the lightning is going to strike, don't you think it would be wiser to make our headquarters in one of the engine-houses in that district?"

The fire marshal agreed, and that night saw us watching at the fire-house nearest the department-store region.

Kennedy and I were assigned to places on the hose-cart and engine, respectively, Kennedy being in the hose-cart so that he could be with McCormick. We were taught to descend one of the four brass poles hand under elbow, from the dormitory on the second floor. They showed us how to jump into the "turn-outs" - a pair of trousers opened out over the high top boots. We were given helmets which we placed in regulation fashion on our rubber coats, turned inside out with the right armhole up. Thus it came about that Craig and I joined the Fire Department temporarily. It was a novel experience for us both.

"Now, Walter," said Kennedy, "as long as we have gone so far, we'll 'roll' to every fire, just like the regulars. We won't take any chances of missing the firebug at any time of night or day."

It proved to be a remarkably quiet evening with only one little blaze in a candy-shop on Seventh Avenue. Most of the time we sat around trying to draw the men out about their thrilling experiences at fires. But if there is one thing the fireman doesn't know it is the English language when talking about himself. It was quite late when we turned into the neat white cots upstairs.

We had scarcely fallen into a half doze in our strange surroundings when the gong downstairs sounded. It was our signal.

We could hear the rapid clatter of the horses' hoofs as they were automatically released from their stalls and the collars and harness mechanically locked about them. All was stir, and motion, and shouts. Craig and I had bounded awkwardly into our paraphernalia at the first sound. We slid ungracefully down the pole and were pushed and shoved into our places, for scientific management in a New York fire-house has reached one hundred per cent efficiency, and we were not to be allowed to delay the game.

The oil-torch had been applied to the engine, and it rolled forth, belching flames. I was hanging on for dear life, now and then catching sight of the driver urging his plunging horses onward like a charioteer in a modern Ben Hur race. The tender with Craig and McCormick was lost in the clouds of smoke and sparks that trailed behind us. On we dashed until we turned into Sixth Avenue. The glare of the sky told us that this time the firebug had made good.

"I'll be hanged if it isn't the Stacey store again, shouted the man next me on the engine as the horses lunged up the avenue and stopped at the allotted hydrant. It was like a war game. Every move had been planned out by the fire-strategists, even down to the hydrants that the engines should take at a given fire.

Already several floors were aflame, the windows glowing like open-hearth furnaces, the glass bulging and cracking and the flames licking upward and shooting out in long streamers. The hose was coupled up in an instant, the water turned on, and the limp rubber and canvas became as rigid as a post with the high pressure of the water being forced through it. Company after company dashed into the blazing "fireproof" building, urged by the hoarse profanity of the chief.

Twenty or thirty men must have disappeared into the stifle from which the police retreated. There was no haste, no hesitation. Everything moved as smoothly as if by clockwork. Yet we could not see one of the men who had disappeared into the burning building. They had been swallowed up, as it were. For that is the way with the New York firemen. They go straight to the heart of the fire. Now and then a stream of a hose spat out of a window, showing that the men were still alive and working. About the ground floors the red-helmeted salvage corps were busy covering up what they could of the goods with rubber sheets to protect them from water. Doctors with black bags and white trousers were working over the injured. Kennedy and I were busy about the engine, and there was plenty for us to do.

Above the shrill whistle for more coal I heard a voice shout, "Began with an explosion - it's the fire- bug, all right." I looked up. It was McCormick, dripping and grimy, in a high state of excitement, talking to Kennedy.

I had been so busy trying to make myself believe that I was really of some assistance about the engine that I had not taken time to watch the fire itself. It was now under control. The sharp and scientific attack had nipped what might have been one of New York's historic conflagrations.

"Are you game to go inside?" I heard McCormick ask.

For answer Kennedy simply nodded. As for me, where Craig went I went.

The three of us drove through the scorching door, past twisted masses of iron still glowing dull red in the smoke and steam, while the water hissed and spattered and slopped. The smoke was still suffocating, and every once in a while we were forced to find air close to the floor and near the wall. My hands and arms and legs felt like lead, yet on we drove.

Coughing and choking, we followed McCormick to what had been the heart of the fire, the office. Men with picks and axes and all manner of cunningly devised instruments were hacking and tearing at the walls and woodwork, putting out the last smouldering sparks while a thousand gallons of water were pouring in at various parts of the building where the fire still showed spirit.

There on the floor of the office lay a charred, shapeless, unrecognisable mass. What was that gruesome odour in the room? Burned human flesh? I recoiled from what had once been the form of a woman.

McCormick uttered a cry, and as I turned my eyes away, I saw him holding a wire with the insulation burned off. He had picked it up from the wreckage of the floor. It led to a bent and blackened can - that had once been a can of ether.

My mind worked rapidly, but McCormick blurted out the words before I could form them, "Caught in her own trap at last!"

Kennedy said nothing, but as one of the firemen roughly but reverently covered the remains with a rubber sheet, he stooped down and withdrew from the breast of the woman a long letter-file. "Come, let us go," he said.

Back in our apartment again we bathed our racking heads, gargled our parched throats, and washed out our bloodshot eyes, in silence. The whole adventure, though still fresh and vivid in my mind, seemed unreal, like a dream. The choking air, the hissing steam, the ghastly object under the tarpaulin - what did it all mean? Who was she? I strove to reason it out, but could find no answer.

It was nearly dawn when the door opened and McCormick came in and dropped wearily into a chair. "Do you know who that woman was?" he gasped. " It was Miss Wend herself."

"Who identified her?" asked Kennedy calmly.

"Oh, several people. Stacey recognised her at once. Then Hartstein, the adjuster for the insured, and Lazard, the adjuster for the company, both of whom had had more or less to do with her in connection with settling up for other fires, recognised her. She was a very clever woman, was Miss Wend, and a very important cog in the Stacey enterprises. And to think she was the firebug, after all. I can hardly believe it."

"Why believe it?" asked Kennedy quietly.

"Why believe it?" echoed McCormick. "Stacey has found shortages in his books due to the operation of her departments. The bookkeeper who had charge of the accounts in her department, a man named Douglas, is missing. She must have tried to cover up her operations by fires and juggling the accounts. Failing in that she tried to destroy Stacey's store itself, twice. She was one of the few that could get into the office unobserved. Oh, it's a clear case now. To my mind, the heavy vapours of ether - they are heavier than air, you know - must have escaped along the surface of the floor last night and become ignited at a considerable distance from where she expected. She was caught in a back-draught, or something of the sort. Well, thank God, we've seen the last of this firebug business. What's that?"

Kennedy had laid the letter-file on the table. "Nothing. Only I found this embedded in Miss Wend's breast right over her heart."

"Then she was murdered?" exclaimed McCormick.

"We haven't come to the end of this case yet," replied Craig evasively. "On the contrary, we have just got our first good clue. No, McCormick, your theory will not hold water. The real point is to find this missing bookkeeper at any cost. You must persuade him to confess what he knows. Offer him immunity - he was only a pawn in the hands of those higher up."

McCormick was not hard to convince. Tired as he was, he grabbed up his hat and started off to put the final machinery in motion to wind up the long chase for the firebug.

"I must get a couple of hours' sleep," he yawned as he left us," but first I want to start something toward finding Douglas. I shall try to see you about noon."

I was too exhausted to go to the office. In fact, I doubt if I could have written a line. But I telephoned in a story of personal experiences at the Stacey fire and told them they could fix it up as they chose and even sign my name to it.

About noon McCormick came in again, looking as fresh as if nothing had happened. He was used to it.

"I know where Douglas is," he announced breathlessly.

"Fine," said Kennedy, "and can you produce him at any time when it is necessary?"

"Let me tell you what I have done. I went down to the district attorney from here - routed him out of bed. He has promised to turn loose his accountants to audit the reports of the adjusters, Hartstein and Lazard, as well as to make a cursory examination of what Stacey books there are left. He says he will have a preliminary report ready to-night, but the detailed report will take days, of course.

"It's the Douglas problem that is difficult, though. I haven't seen him, but one of the central-office men, by shadowing his wife, has found that he is in hiding down on the East Side. He's safe there; he can't make a move to get away without being arrested. The trouble is that if I arrest him, the people higher up will know it and will escape before I can get his confession and the warrants. I'd much rather have the whole thing done at once. Isn't there some way we can get the whole Stacey crowd together, make the arrest of Douglas and nab the guilty ones in the case, all together without giving them a chance to escape or to shield the real firebug?"

Kennedy thought a moment. "Yes," he answered slowly. "There is. If you can get them all together at my laboratory to-night at, say, eight o'clock, I'll give you two clear hours to make the arrest of Douglas, get the confession, and swear out the warrants. All that you'll need to do is to let me talk a few minutes this afternoon with the judge who will sit in the night court to-night. I shall install a little machine on his desk in the court, and we'll catch the real criminal - he'll never get a chance to cross the state line or disappear in any way. You see, my laboratory will be neutral ground. I think you can get them to come, inasmuch as they know the bookkeeper is safe and that dead women tell no tales."

When next I saw Kennedy it was late in the afternoon, in the laboratory. He was arranging something in the top drawer of a flat-top desk. It seemed to be two instruments composed of many levers and discs and magnets, each instrument with a roll of paper about five inches wide. On one was a sort of stylus with two silk cords attached at right angles to each other near the point. On the other was a capillary glass tube at the junction of two aluminum arms, also at right angles to each other.

It was quite like old times to see Kennedy at work in his laboratory preparing for a "seance." He said nothing as I watched him curiously, and I asked nothing. Two sets of wires were attached to each of the instruments, and these he carefully concealed and led out the window. Then he arranged the chairs on the opposite side of the desk from his own.

"Walter," he said, "when our guests begin to arrive I want you to be master of ceremonies. Simply keep them on the opposite side of the desk from me. Don't let them move their chairs around to the right or left. And, above all, leave the doors open. I don't want any one to be suspicious or to feel that he is shut in in any way. Create the impression that they are free to go and come when they please."

Stacey arrived first in a limousine which he left standing at the door of the Chemistry Building. Bloom and Warren came together in the latter's car. Lazard came in a taxicab which he dismissed, and Hartstein came up by the subway, being the last to arrive. Every one seemed to be in good humour.

I seated them as Kennedy had directed. Kennedy pulled out the extension on the left of his desk and leaned his elbow on it as he began to apologise for taking up their time at such a critical moment. As near as I could make out, he had quietly pulled out the top drawer of his desk on the right, the drawer in which I had seen him place the complicated apparatus. But as nothing further happened I almost forgot about it in listening to him. He began by referring to the burned papers he had found in the office.

"It is sometimes possible," he continued, "to decipher writing on burned papers if one is careful. The processes of colour photography have recently been applied to obtain a legible photograph of the writing on burned manuscripts which are unreadable by any other known means. As long as the sheet has not been entirely disintegrated positive results can be obtained every time. The charred manuscript is carefully arranged in as near its original shape as possible, on a sheet of glass and covered with a drying varnish, after which it is backed by another sheet of glass.

"By using carefully selected colour screens and orthochromatic plates a perfectly legible photograph of the writing may be taken, although there may be no marks on the charred remains that are visible to the eye. This is the only known method in many cases. I have here some burned fragments of paper which I gathered up after the first attempt to fire your store, Mr. Stacey."

Stacey coughed in acknowledgment. As for Craig, he did not mince matters in telling what he had found.

"Some were notes given in favour of Rebecca Wend and signed by Joseph Stacey," he said quietly. "They represent a large sum of money in the aggregate. Others were memoranda of Miss Wend's, and still others were autograph letters to Miss Wend of a very incriminating nature in connection with the fires by another person."

Here he laid the "A. Spark" letters on the desk before him. "Now," he added "some one, in a spirit of bravado, sent these notes to the fire marshal at various times. Curiously enough, I find that the handwriting of the first one bears a peculiar resemblance to that of Miss Wend, while the second and third, though disguised also, greatly suggest the handwriting of Miss Wend's correspondent."

No one moved. But I sat aghast. She had been a part of the conspiracy, after all, not a pawn. Had they played fair?

"Taking up next the remarkable succession of fires," resumed Kennedy, "this case presents some unique features. In short, it is a clear case of what is known as a 'firebug trust.' Now just what is a firebug trust? Well, it is, as near as I can make out, a combination of dishonest merchants and insurance adjusters engaged in the business of deliberately setting fires for profit. These arson trusts are not the ordinary kind of firebugs whom the firemen plentifully damn in the fixed belief that one-fourth of all fires are kindled by incendiaries. Such 'trusts' exist all over the country. They have operated in Chicago, where they are said to have made seven hundred and fifty thousand dollars in one year. Another group is said to have its headquarters in Kansas City. Others have worked in St. Louis, Pittsburgh, Cleveland, and Buffalo. The fire marshals of Illinois, Kentucky, Tennessee, and Ohio have investigated their work. But until recently New York has been singularly free from the organised work of this sort. Of course we have plenty of firebugs and pyromaniacs in a small way, but the big conspiracy has never come to my personal attention before.

"Now, the Jones-Green fire, the Quadrangle fire, the Slawson Building fire, and the rest, have all been set for one purpose - to collect insurance. I may as well say right here that some people are in bad in this case, but that others are in worse. Miss Wend was originally a party to the scheme. Only the trouble with Miss Wend was that she was too shrewd to be fooled. She insisted that she have her full share of the pickings. In that case it seems to have been the whole field against Miss Wend, not a very gallant thing, nor yet according to the adage about honour among thieves.

"A certain person whose name I am frank to say I do not know - yet - conceived the idea of destroying the obligations of the Stacey companies to Miss Wend as well as the incriminating evidence which she held of the 'firebug trust,' of which she was a member up to this time. The plan only partly succeeded. The chief coup, which was to destroy he Stacey store into the bargain, miscarried.

"What was the result? Miss Wend, who had been hand in glove with the 'trust,' was now a bitter enemy, perhaps would turn state's evidence. What more natural than to complete the conspiracy by carrying out the coup and at the same time get rid of the dangerous enemy of the conspirators? I believe that Miss Wend was lured under some pretext or other to the Stacey store on the night of the big fire. The person who wrote the second and third 'A. Spark' letters did it. She was murdered with this deadly instrument" - Craig laid the letter-file on the table - "and it was planned to throw the entire burden of suspicion on her by asserting that there was a shortage in the books of her department."

"Pooh!" exclaimed Stacey, smoking complacently at his cigar. "We have been victimised in those fires by people who have grudges against us, labour unions and others. This talk of an arson trust is bosh - yellow journalism. More than that, we have been systematically robbed by a trusted head of a department, and the fire at Stacey's was the way the thief took to cover - er - her stealings. At the proper time we shall produce the bookkeeper Douglas and prove it.

Kennedy fumbled in the drawer of the desk, then drew forth a long strip of paper covered with figures. "All the Stacey companies," he said, "have been suffering from the depression that exists in the trade at present. They are insolvent. Glance over that, Stacey. It is a summary of the preliminary report of the accountants of the district attorney who have been going over your books to-day."

Stacey gasped. "How did you get it? The report was not to be ready until nine o'clock, and it is scarcely a quarter past now."

"Never mind how I got it. Go over it with the adjusters, anybody. I think you will find that there was no shortage in Miss Wend's department, that you were losing money, that you were in debt to Miss Wend, and that she would have received the lion's share of the proceeds of the insurance if the firebug scheme had turned out as planned."

"We absolutely repudiate these figures as fiction," said Stacey, angrily turning toward Kennedy after a hurried consultation.

Perhaps, then, you'll appreciate this," replied Craig, pulling another piece of paper from the desk. "I'll read it. 'Henry Douglas, being duly sworn, deposes and says that one' - we'll call him 'Blank' for the present - 'with force and arms did feloniously, wilfully, and intentionally kill Rebecca Wend whilst said Blank was wilfully burning and setting on fire - "

"One moment," interrupted Stacey. "Let me see that paper."

Kennedy laid it down so that only the signature showed. The name was signed in a full round hand, "Henry Douglas."

"It's a forgery," cried Stacey in rage. "Not an hour before I came into this place I saw Henry Douglas. He had signed no such paper then. He could not have signed it since, and you could not have received it. I brand that document as a forgery."

Kennedy stood up and reached down into the open drawer on the right of his desk. From it he lifted the two machines I had seen him place there early in the evening.

Gentlemen," he said, " this is the last scene of the play you are enacting. You see here on the desk an instrument that was invented many years ago, but has only recently become really practical. It is the telautograph - the long-distance writer. In this new form it can be introduced into the drawer of a desk for the use of any one who may wish to make inquiries, say, of clerks without the knowledge of a caller. It makes it possible to write a message under these conditions and receive an answer concerning the personality or business of the individual seated at one's elbow without leaving the desk or seeming to make inquiries.

"With an ordinary pencil I have written on the paper of the transmitter. The silk cord attached to the pencil regulates the current which controls a pencil at the other end of the line. The receiving pencil moves simultaneously with my pencil. It is the principle of the pantograph cut in half, one half here, the other half at the end of the line, two telephone wires in this case connecting the halves.

"While we have been sitting here I have had my right hand in the half-open drawer of my desk writing with this pencil notes of what has transpired in this room. These notes, with other evidence, have been simultaneously placed before Magistrate Brenner in the night court. At the same time, on this other, the receiving, instrument the figures of the accountants written in court have been reproduced here. You have seen them. Meanwhile. Douglas was arrested, taken before the magistrate, and the information for a charge of murder in the first degree perpetrated in committing arson has been obtained. You have seen it. It came in while you were reading the figures."

The conspirators seemed dazed.

"And now," continued Kennedy, "I see that the pencil of the receiving instrument is writing again. Let us see what it is."

We bent over. The writing started: "County of New York. In the name of the People of the State of New York - "

Kennedy did not wait for us to finish reading. He tore the writing from the telautograph and waved it over his head.

"It is a warrant. You are all under arrest for arson. But you, Samuel Lazard, are also under arrest for the murder of Rebecca Wend and six other persons in fires which you have set. You are the real firebug, the tool of Joseph Stacey, perhaps, but that will all come out in the trial. McCormick, McCormick," called Craig, "it's all right. I have the warrant. Are the police there?"

There was no answer.

Lazard and Stacey made a sudden dash for the door, and in an instant they were in Stacey's waiting car. The chauffeur took off the brake and pulled the lever. Suddenly Craig's pistol flashed, and the chauffeur's arms hung limp and useless on the steering-wheel.

As McCormick with the police loomed up, a moment late, out of the darkness and after a short struggle clapped the irons on Stacey and Lazard in Stacey's own magnificently upholstered car, I remarked reproachfully to Kennedy: "But, Craig, you have shot the innocent chauffeur. Aren't you going to attend to him?"

"Oh," replied Kennedy nonchalantly, "don't worry about that. They were only rock-salt bullets. They didn't penetrate far. They'll sting for some time, but they're antiseptic, and they'll dissolve and absorb quickly."



V

THE CONFIDENCE KING

"Shake hands with Mr. Burke of the secret service, Professor Kennedy."

It was our old friend First Deputy O'Connor who thus in his bluff way introduced a well-groomed and prosperous-looking man whom he brought up to our apartment one evening.

The formalities were quickly over. "Mr. Burke and I are old friends," explained O'Connor. "We try to work together when we can, and very often the city department can give the government service a lift, and then again it's the other way - as it was in the trunk-murder mystery. Show Professor Kennedy the 'queer,' Tom."

Burke drew a wallet out of his pocket, and from it slowly and deliberately selected a crisp, yellow-backed hundred-dollar bill. He laid it flat on the table before us. Diagonally across its face from the upper left- to the lower right-hand corner extended two parallel scorings in indelible ink.

Not being initiated into the secrets of the gentle art of "shoving the queer," otherwise known as passing counterfeit money, I suppose my questioning look betrayed me.

"A counterfeit, Walter," explained Kennedy. "That's what they do with bills when they wish to preserve them as records in the secret service and yet render them valueless."

Without a word Burke handed Kennedy a pocket magnifying-glass, and Kennedy carefully studied the bill. He was about to say something when Burke opened his capacious wallet again and laid down a Bank of England five-pound note which had been similarly treated.

Again Kennedy looked through the glass with growing amazement written on his face, but before he could say anything, Burke laid down an express money-order on the International Express Company.

"I say," exclaimed Kennedy, putting down the glass, "stop! How many more of these are there?"

Burke smiled. "That's all," he replied, "but it's not the worst."

"Not the worst? Good heavens, man, next you'll tell me that the government is counterfeiting its own notes! How much of this stuff do you suppose has been put into circulation?"

Burke chewed a pencil thoughtfully, jotted down some figures on a piece of paper, and thought some more. "Of course I can't say exactly, but from hints I have received here and there I should think that a safe bet would be that some one has cashed in upward of half a million dollars already."

"Whew," whistled Kennedy, "that's going some. And I suppose it is all salted away in some portable form. What an inventory if must be - good bills, gold, diamonds, and jewellery. This is a stake worth playing for."

"Yes," broke in O'Connor, "but from my standpoint, professionally, I mean, the case is even worse than that. It's not the counterfeits that bother us. We understand that, all right. But," and he leaned forward earnestly and brought his fist down hard on the table with a resounding Irish oath, "the finger-print system, the infallible finger-print system, has gone to pieces. We've just imported this new 'portrait parle' fresh from Paris and London, invented by Bertillon and all that sort of thing - it has gone to pieces, too. It's a fine case, this is, with nothing left of either scientific or unscientific criminal-catching to rely on. There - what do you know about that?"

"You'll have to tell me the facts first," said Kennedy. "I can't diagnose your disease until I know the symptoms."

"It's like this," explained Burke, the detective in him showing now with no effort at concealment. "A man, an Englishman, apparently, went into a downtown banker's office about three months ago and asked to have some English bank-notes exchanged for American money. After he had gone away, the cashier began to get suspicious. He thought there was something phoney in the feel of the notes. Under the glass he noticed that the little curl on the 'e' of the 'Five' was missing. It's the protective mark. The water-mark was quite equal to that of the genuine - maybe better. Hold that note up to the light and see for yourself.

"Well, the next day, down to the Custom House, where my office is, a man came who runs a swell gambling-house uptown. He laid ten brand-new bills on my desk. An Englishman had been betting on the wheel. He didn't seem to care about winning, and he cashed in each time with a new one-hundred-dollar bill. Of course he didn't care about winning. He cared about the change - that was his winning. The bill on the table is one of the original ten, though since then scores have been put into circulation. I made up my mind that it was the same Englishman in both cases.

"Then within a week, in walked the manager of the Mozambique Hotel - he had been stung with the fake International Express money-order - same Englishman, too, I believe."

"And you have no trace of him?" asked Kennedy eagerly.

"We had him under arrest once - we thought. A general alarm was sent out, of course, to all the banks and banking-houses. But the man was too clever to turn up in that way again. In one gambling-joint which women frequent a good deal, a classy dame who might have been a duchess or a - well, she was a pretty good loser and always paid with hundred-dollar bills. Now, you know women are not good losers. Besides, the hundred-dollar-bill story had got around among the gambling-houses. This joint thought it worth taking a chance, so they called me up on the 'phone, extracted a promise that I'd play fair and keep O'Connor from raiding them, but wouldn't I please come up and look over the dame of the yellow bills? Of course I made a jump at it. Sure enough, they were the same counterfeits. I could tell because the silk threads were drawn in with coloured ink. But instead of making an arrest I decided to trail the lady.

"Now, here comes the strange part of it. Let me see, this must have been over two months ago. I followed her out to a suburban town, Riverwood along the Hudson, and to a swell country house overlooking the river, private drive, stone gate, hedges, old trees, and all that sort of thing. A sporty-looking Englishman met her at the gate with one of those big imported touring-cars, and they took a spin.

"I waited a day or so, but nothing more happened, and I began to get anxious. Perhaps I was a bit hasty. Anyhow I watched my chance and made an arrest of both of them when they came to New York on a shopping expedition. You should have heard that Englishman swear. I didn't know such language was possible. But in his pocket we found twenty more of those hundred-dollar bills - that was all. Do you think he owned up? Not a bit of it. He swore he had picked the notes up in a pocketbook on the pier as he left the steamer. I laughed. But when he was arraigned in court he told the magistrate the same story and that he had advertised his find at the time. Sure enough, in the files of the papers we discovered in the lost-and-found column the ad, just as he claimed. We couldn't even prove that he had passed the bills. So the magistrate refused to hold them, and they were both released. But we had had them in our power long enough to take their finger-prints and get descriptions and measurements of them, particularly by this new 'portrait parle ' system. We felt we could send out a strange detective and have him pick them out of a crowd - you know the system, I presume?

Kennedy nodded, and I made a mental note of finding out more about the "portrait parle" later.

Burke paused, and O'Connor prompted, "Tell them about Scotland Yard, Tom."

"Oh, yes," resumed Burke. "Of course I sent copies of the finger-prints to Scotland Yard. Within two weeks they replied that one set belonged to William Forbes, a noted counterfeiter, who, they understood, had sailed for South Africa but had never arrived there. They were glad to learn that he was in America, and advised me to look after him sharply. The woman was also a noted character - Harriet Wollstone, an adventuress."

"I suppose you have shadowed them ever since?" Kennedy asked.

"Yes, a few days after they were arrested the man had an accident with his car. It was said he was cranking the engine and that it kicked back and splintered the bone in his forearm. Anyhow, he went about with his hand and arm in a sling."

"And then?"

"They gave my man the slip that night in their fast touring-car. You know automobiles have about made shadowing impossible in these days. The house was closed up, and it was said by the neighbours that Williams and Mrs. Williams - as they called themselves - had gone to visit a specialist in Philadelphia. Still, as they had a year's lease on the house, I detailed a man to watch it more or less all the time. They went to Philadelphia all right; some of the bills turned up there. But we saw nothing of them.

"A short time ago, word came to me that the house was open again. It wasn't two hours later that the telephone rang like mad. A Fifth Avenue jeweller had just sold a rope of pearls to an Englishwoman who paid for it herself in crisp new one-hundred-dollar bills. The bank had returned them to him that very afternoon - counterfeits. I didn't lose any time making a second arrest up at the house of mystery at Riverwood. I had the county authorities hold them - and, now, O'Connor, tell the rest of it. You took the finger-prints up there."

O'Connor cleared his throat as if something stuck in it, in the telling. "The Riverwood authorities refused to hold them," he said with evident chagrin. "As soon as I heard of the arrest I started up myself with the finger-print records to help Burke. It was the same man, all right - I'll swear to that on a stack of Bibles. So will Burke. I'll never forget that snub nose - the concave nose, the nose being the first point of identification in the 'portrait park.' And the ears, too - oh, it was the same man, all right. But when we produced the London finger-prints which tallied with the New York finger-prints which we had made - believe it or not, but it is a fact, the Riverwood finger-prints did not tally at all."

He laid the prints on the table. Kennedy examined them closely. His face clouded. It was quite evident that he was stumped, and he said so. "There are some points of agreement," he remarked, "but more points of difference. Any points of difference are usually considered fatal to the finger-print theory.