"But evidently it could not be done without exciting all kinds of rumors and suspicions. Stories seem to have spread far and fast about what he had discovered. He realized the unsettled condition of the country—perhaps wanted to confirm his reading of a certain inscription by consultation with one scholar whom he thought he could trust. At any rate, he came home."

Kennedy paused, making use of the silence for emphasis. "You have all read of the wealth that Cortez found in Mexico. Where are the gold and silver of the conquistadores? Gone to the melting pot, centuries ago. But is there none left? The Indians believe so. There are persons who would stop at nothing—even at murder of American professors, murder of their own comrades, to get at the secret."

He laid his hand almost lovingly on his powerful little microscope as he resumed on another line of evidence.

"And while we are on the subject of murders, two very similar deaths have occurred," he went on. "It is of no use to try to gloss them over. Frankly, I suspected that they might have been caused by aconite poisoning. But, in the case of such poisoning, not only is the lethal dose very small but our chemical methods of detection are nil. The dose of the active principle, aconitin nitrate, is about one six-hundredth of a grain. There are no color tests, no reactions, as in the case of the other organic poisons."

I wondered what he was driving at. Was there, indeed, no test? Had the murderer used the safest of poisons—one that left no clue? I looked covertly at Sato's face. It was impassive. Doctor Bernardo was visibly uneasy as Kennedy proceeded. Cool enough up to the time of the mention of the treasure, I fancied, now, that he was growing more and more nervous.

Craig laid down on the table the reed stick with the little darkened cylinder on the end.

"That," he said, "is a little article which I picked up beneath Northrop's window yesterday. It is a piece of anno-noki, or bushi." I fancied I saw just a glint of satisfaction in Otaka's eyes.

"Like many barbarians," continued Craig, "the Ainus from time immemorial have prepared virulent poisons with which they charged their weapons of the chase and warfare. The formulas for the preparations, as in the case of other arrow poisons of other tribes, are known only to certain members, and the secret is passed down from generation to generation as an heirloom, as it were. But in this case it is no longer a secret. It has now been proved that the active principle of this poison is aconite."

"If that is the case," broke in Doctor Leslie, "it is hopeless to connect anyone directly in that way with these murders. There is no test for aconitin."

I thought Sato's face was more composed and impassive than ever. Doctor Bernardo, however, was plainly excited.

"What—no test—NONE?" asked Kennedy, leaning forward eagerly. Then, as if he could restrain the answer to his own question no longer, he shot out: "How about the new starch test just discovered by Professor Reichert, of the University of Pennsylvania? Doubtless you never dreamed that starch may be a means of detecting the nature of a poison in obscure cases in criminology, especially in cases where the quantity of poison necessary to cause death is so minute that no trace of it can be found in the blood.

"The starch method is a new and extremely inviting subject to me. The peculiarities of the starch of any plant are quite as distinctive of the plant as are those of the hemoglobin crystals in the blood of an animal. I have analyzed the evidence of my microscope in this case thoroughly. When the arrow poison is introduced subcutaneously—say, by a person shooting a poisoned dart, which he afterward removes in order to destroy the evidence- -the lethal constituents are rapidly absorbed.

"But the starch remains in the wound. It can be recovered and studied microscopically and can be definitely recognized. Doctor Reichert has published a study of twelve hundred such starches from all sorts of plants. In this case, it not only proves to be aconitin but the starch granules themselves can be recognized. They came from this piece of arrow poison."

Every eye was fixed on him now.

"Besides," he rapped out, "in the soft soil beneath the window of Professor Northrop's room, I found footprints. I have only to compare the impressions I took there and those of the people in this room, to prove that, while the real murderer stood guard below the window, he sent some one more nimble up the rain pipe to shoot the poisoned dart at Professor Northrop, and, later, to let down a rope by which he, the instigator, could gain the room, remove the dart, and obtain the key to the treasure he sought."

Kennedy was looking straight at Professor Bernardo.

"A friend of mine in Mexico has written me about an inscription," he burst out. "I received the letter only to-day. As nearly as I can gather, there was an impression that some of Northrop's stuff would be valuable in proving the alleged kinship between Mexico and Japan, perhaps to arouse hatred of the United States."

"Yes—that is all very well," insisted Kennedy. "But how about the treasure?"

"Treasure?" repeated Bernardo, looking from one of us to another.

"Yes," pursued Craig relentlessly, "the treasure. You are an expert in reading the hieroglyphics. By your own statement, you and Northrop had been going over the stuff he had sent up. You know it."

Bernardo gave a quick glance from Kennedy to me. Evidently he saw that the secret was out.

"Yes," he said huskily, in a low tone, "Northrop and I were to follow the directions after we had plotted them out and were to share it together on the next expedition, which I could direct as a Mexican without so much suspicion. I should still have shared it with his widow if this unfortunate affair had not exposed the secret."

Bernardo had risen earnestly.

"Kennedy," he cried, "before God, if you will get back that stone and keep the secret from going further than this room, I will prove what I have said by dividing the Mixtec treasure with Mrs. Northrop and making her one of the richest widows in the country!"

"That is what I wanted to be sure of," nodded Craig. "Bernardo, Senora Herreria, of whom your friend wrote to you from Mexico, has been murdered in the same way that Professor Northrop was. Otaka was sent by her husband to murder Northrop, in order that they might obtain the so-called 'Pillar of Death' and the key to the treasure. Then, when the senora was no doubt under the influence of sake in the pretty little Oriental bower at the curio shop, a quick jab, and Otaka had removed one who shared the secret with them."

He had turned and faced the pair.

"Sato," he added, "you played on the patriotism of the senora until you wormed from her the treasure secret. Evidently rumors of it had spread from Mexican Indians to Japanese visitors. And then, Otaka, all jealousy over one whom she, no doubt, justly considered a rival, completed your work by sending her forth to die, unknown, on the street. Walter, ring up First Deputy O'Connor. The stone is hidden somewhere in the curio shop. We can find it without Sato's help. The quicker such a criminal is lodged safely in jail, the better for humanity."

Sato was on his feet, advancing cautiously toward Craig. I knew the dangers, now, of anno-noki, as well as the wonders of jujutsu, and, with a leap, I bounded past Bernardo and between Sato and Kennedy.

How it happened, I don't know, but, an instant later, I was sprawling.

Before I could recover myself, before even Craig had a chance to pull the hair-trigger of his automatic, Sato had seized the Ainu arrow poison from the table, had bitten the little cylinder in half, and had crammed the other half into the mouth of Otaka.



CHAPTER XIII

THE RADIUM ROBBER

Kennedy simply reached for the telephone and called an ambulance. But it was purely perfunctory. Dr. Leslie himself was the only official who could handle Sato's case now.

We had planned a little vacation for ourselves, but the planning came to naught. The next night we spent on a sleeper. That in itself is work to me.

It all came about through a hurried message from Murray Denison, president of the Federal Radium Corporation. Nothing would do but that he should take both Kennedy and myself with him post-haste to Pittsburgh at the first news of what had immediately been called "the great radium robbery."

Of course the newspapers were full of it. The very novelty of an ultra-modern cracksman going off with something worth upward of a couple of hundred thousand dollars—and all contained in a few platinum tubes which could be tucked away in a vest pocket—had something about it powerfully appealing to the imagination.

"Most ingenious, but, you see, the trouble with that safe is that it was built to keep radium IN—not cracksmen OUT," remarked Kennedy, when Denison had rushed us from the train to take a look at the little safe in the works of the Corporation.

"Breaking into such a safe as this," added Kennedy, after a cursory examination, "is simple enough, after all."

It was, however, a remarkably ingenious contrivance, about three feet in height and of a weight of perhaps a ton and a half, and all to house something weighing only a few grains.

"But," Denison hastened to explain, "we had to protect the radium not only against burglars, but, so to speak, against itself. Radium emanations pass through steel and experiments have shown that the best metal to contain them is lead. So, the difficulty was solved by making a steel outer case enclosing an inside leaden shell three inches thick."

Kennedy had been toying thoughtfully with the door.

"Then the door, too, had to be contrived so as to prevent any escape of the emanations through joints. It is lathe turned and circular, a 'dead fit.' By means of a special contrivance any slight looseness caused by wear and tear of closing can be adjusted. And another feature. That is the appliance for preventing the loss of emanation when the door is opened. Two valves have been inserted into the door and before it is opened tubes with mercury are passed through which collect and store the emanation."

"All very nice for the radium," remarked Craig cheerfully. "But the fellow had only to use an electric drill and the gram or more of radium was his."

"I know that—now," ruefully persisted Denison. "But the safe was designed for us specially. The fellow got into it and got away, as far as I can see, without leaving a clue."

"Except one, of course," interrupted Kennedy quickly.

Denison looked at him a moment keenly, then nodded and said, "Yes- -you are right. You mean one which he must bear on himself?"

"Exactly. You can't carry a gram or more of radium bromide long with impunity. The man to look for is one who in a few days will have somewhere on his body a radium burn which will take months to heal. The very thing he stole is a veritable Frankenstein's monster bent on the destruction of the thief himself!"

Kennedy had meanwhile picked up one of the Corporation's circulars lying on a desk. He ran his eye down the list of names.

"So, Hartley Haughton, the broker, is one of your stockholders," mused Kennedy.

"Not only one but THE one," replied Denison with obvious pride.

Haughton was a young man who had come recently into his fortune, and, while no one believed it to be large, he had cut quite a figure in Wall Street.

"You know, I suppose," added Denison, "that he is engaged to Felicie Woods, the daughter of Mrs. Courtney Woods?"

Kennedy did not, but said nothing.

"A most delightful little girl," continued Denison thoughtfully. "I have known Mrs. Woods for some time. She wanted to invest, but I told her frankly that this is, after all, a speculation. We may not be able to swing so big a proposition, but, if not, no one can say we have taken a dollar of money from widows and orphans."

"I should like to see the works," nodded Kennedy approvingly.

"By all means."

The plant was a row of long low buildings of brick on the outskirts of the city, once devoted to the making of vanadium steel. The ore, as Denison explained, was brought to Pittsburgh because he had found here already a factory which could readily be turned into a plant for the extraction of radium. Huge baths and vats and crucibles for the various acids and alkalis and other processes used in treating the ore stood at various points.

"This must be like extracting gold from sea water," remarked Kennedy jocosely, impressed by the size of the plant as compared to the product.

"Except that after we get through we have something infinitely more precious than gold," replied Denison, "something which warrants the trouble and outlay. Yes, the fact is that the percentage of radium in all such ores is even less than of gold in sea water."

"Everything seems to be most carefully guarded," remarked Kennedy as we concluded our tour of the well-appointed works.

He had gone over everything in silence, and now at last we had returned to the safe.

"Yes," he repeated slowly, as if confirming his original impression, "such an amount of radium as was stolen wouldn't occasion immediate discomfort to the thief, I suppose, but later no infernal machine could be more dangerous to him."

I pictured to myself the series of fearful works of mischief and terror that might follow, a curse on the thief worse than that of the weirdest curses of the Orient, the danger to the innocent, and the fact that in the hands of a criminal it was an instrument for committing crimes that might defy detection.

"There is nothing more to do here now," he concluded. "I can see nothing for the present except to go back to New York. The telltale burn may not be the only clue, but if the thief is going to profit by his spoils we shall hear about it best in New York or by cable from London, Paris, or some other European city."

Our hurried departure from New York had not given us a chance to visit the offices of the Radium Corporation for the distribution of the salts themselves. They were in a little old office building on William Street, near the drug district and yet scarcely a moment's walk from the financial district.

"Our head bookkeeper, Miss Wallace, is ill," remarked Denison when we arrived at the office, "but if there is anything I can do to help you, I shall be glad to do it. We depend on Miss Wallace a great deal. Haughton says she is the brains of the office."

Kennedy looked about the well-appointed suite curiously.

"Is this another of those radium safes?" he asked, approaching one similar in appearance to that which had been broken open already.

"Yes, only a little larger."

"How much is in it?"

"Most of our supply. I should say about two and a half grams. Miss Wallace has the record."

"It is of the same construction, I presume," pursued Kennedy. "I wonder whether the lead lining fits closely to the steel?"

"I think not," considered Denison. "As I remember there was a sort of insulating air cushion or something of the sort."

Denison was quite eager to show us about. In fact ever since he had hustled us out to view the scene of the robbery, his high nervous tension had given us scarcely a moment's rest. For hours he had talked radium, until I felt that he, like his metal, must have an inexhaustible emanation of words. He was one of those nervous, active little men, a born salesman, whether of ribbons or radium.

"We have just gone into furnishing radium water," he went on, bustling about and patting a little glass tank.

I looked closely and could see that the water glowed in the dark with a peculiar phosphorescence.

"The apparatus for the treatment," he continued, "consists of two glass and porcelain receptacles. Inside the larger receptacle is placed the smaller, which contains a tiny quantity of radium. Into the larger receptacle is poured about a gallon of filtered water. The emanation from that little speck of radium is powerful enough to penetrate its porcelain holder and charge the water with its curative properties. From a tap at the bottom of the tank the patient draws the number of glasses of water a day prescribed. For such purposes the emanation within a day or two of being collected is as good as radium itself. Why, this water is five thousand times as radioactive as the most radioactive natural spring water."

"You must have control of a comparatively large amount of the metal," suggested Kennedy.

"We are, I believe, the largest holders of radium in the world," he answered. "I have estimated that all told there are not much more than ten grams, of which Madame Curie has perhaps three, while Sir Ernest Cassel of London is the holder of perhaps as much. We have nearly four grams, leaving about six or seven for the rest of the world."

Kennedy nodded and continued to look about.

"The Radium Corporation," went on Denison, "has several large deposits of radioactive ore in Utah in what is known as the Poor Little Rich Valley, a valley so named because from being about the barrenest and most unproductive mineral or agricultural hole in the hills, the sudden discovery of the radioactive deposits has made it almost priceless."

He had entered a private office and was looking over some mail that had been left on his desk during his absence.

"Look at this," he called, picking up a clipping from a newspaper which had been laid there for his attention. "You see, we have them aroused."

We read the clipping together hastily:

PLAN TO CORNER WORLD'S RADIUM

LONDON.—Plans are being matured to form a large corporation for the monopoly of the existing and future supply of radium throughout the world. The company is to be called Universal Radium, Limited, and the capital of ten million dollars will be offered for public subscription at par simultaneously in London, Paris and New York.

The company's business will be to acquire mines and deposits of radioactive substances as well as the control of patents and processes connected with the production of radium. The outspoken purpose of the new company is to obtain a world-wide monopoly and maintain the price.

"Ah—a competitor," commented Kennedy, handing back the clipping.

"Yes. You know radium salts used always to come from Europe. Now we are getting ready to do some exporting ourselves. Say," he added excitedly, "there's an idea, possibly, in that."

"How?" queried Craig.

"Why, since we should be the principal competitors to the foreign mines, couldn't this robbery have been due to the machinations of these schemers? To my mind, the United States, because of its supply of radium-bearing ores, will have to be reckoned with first in cornering the market. This is the point, Kennedy. Would those people who seem to be trying to extend their new company all over the world stop at anything in order to cripple us at the start?"

How much longer Denison would have rattled on in his effort to explain the robbery, I do not know. The telephone rang and a reporter from the Record, who had just read my own story in the Star, asked for an interview. I knew that it would be only a question of minutes now before the other men were wearing a path out on the stairs, and we managed to get away before the onrush began.

"Walter," said Kennedy, as soon as we had reached the street. "I want to get in touch with Halsey Haughton. How can it be done?"

I could think of nothing better at that moment than to inquire at the Star's Wall Street office, which happened to be around the corner. I knew the men down there intimately, and a few minutes later we were whisked up in the elevator to the office.

They were as glad to see me as I was to see them, for the story of the robbery had interested the financial district perhaps more than any other.

"Where can I find Halsey Haughton at this hour?" I asked.

"Say," exclaimed one of the men, "what's the matter? There have been all kinds of rumors in the Street about him to-day. Did you know he was ill?"

"No," I answered. "Where is he?"

"Out at the home of his fiancee, who is the daughter of Mrs. Courtney Woods, at Glenclair."

"What's the matter?" I persisted.

"That's just it. No one seems to know. They say—well—they say he has a cancer."

Halsey Haughton suffering from cancer? It was such an uncommon thing to hear of a young man that I looked up quickly in surprise. Then all at once it flashed over me that Denison and Kennedy had discussed the matter of burns from the stolen radium. Might not this be, instead of cancer, a radium burn?

Kennedy, who had been standing a little apart from me while I was talking with the boys, signaled to me with a quick glance not to say too much, and a few minutes later we were on the street again.

I knew without being told that he was bound by the next train to the pretty little New Jersey suburb of Glenclair.

It was late when we arrived, yet Kennedy had no hesitation in calling at the quaint home of Mrs. Courtney Woods on Woodridge Avenue.

Mrs. Woods, a well-set-up woman of middle age, who had retained her youth and good looks in a remarkable manner, met us in the foyer. Briefly, Kennedy explained that we had just come in from Pittsburgh with Mr. Denison and that it was very important that we should see Haughton at once.

We had hardly told her the object of our visit when a young woman of perhaps twenty-two or three, a very pretty girl, with all the good looks of her mother and a freshness which only youth can possess, tiptoed quietly downstairs. Her face told plainly that she was deeply worried over the illness of her fiance.

"Who is it, mother?" she whispered from the turn in the stairs. "Some gentlemen from the company? Hartley's door was open when the bell rang, and he thought he heard something said about the Pittsburgh affair."

Though she had whispered, it had not been for the purpose of concealing anything from us, but rather that the keen ears of her patient might not catch the words. She cast an inquiring glance at us.

"Yes," responded Kennedy in answer to her look, modulating his tone. "We have just left Mr. Denison at the office. Might we see Mr. Haughton for a moment? I am sure that nothing we can say or do will be as bad for him as our going away, now that he knows that we are here."

The two women appeared to consult for a moment.

"Felicie," called a rather nervous voice from the second floor, "is it some one from the company?"

"Just a moment, Hartley," she answered, then, lower to her mother, added, "I don't think it can do any harm, do you, mother?"

"You remember the doctor's orders, my dear."

Again the voice called her.

"Hang the doctor's orders," the girl exclaimed, with an air of almost masculinity. "It can't be half so bad as to have him worry. Will you promise not to stay long? We expect Dr. Bryant in a few moments, anyway."



CHAPTER XIV

THE SPINTHARISCOPE

We followed her upstairs and into Haughton's room, where he was lying in bed, propped up by pillows. Haughton certainly was ill. There was no mistake about that. He was a tall, gaunt man with an air about him that showed that he found illness very irksome. Around his neck was a bandage, and some adhesive tape at the back showed that a plaster of some sort had been placed there.

As we entered his eyes traveled restlessly from the face of the girl to our own in an inquiring manner. He stretched out a nervous hand to us, while Kennedy in a few short sentences explained how we had become associated with the case and what we had seen already.

"And there is not a clue?" he repeated as Craig finished.

"Nothing tangible yet," reiterated Kennedy. "I suppose you have heard of this rumor from London of a trust that is going into the radium field internationally?"

"Yes," he answered, "that is the thing you read to me in the morning papers, you remember, Felicie. Denison and I have heard such rumors before. If it is a fight, then we shall give them a fight. They can't hold us up, if Denison is right in thinking that they are at the bottom of this—this robbery."

"Then you think he may be right?" shot out Kennedy quickly.

Haughton glanced nervously from Kennedy to me.

"Really," he answered, "you see how impossible it is for me to have an opinion? You and Denison have been over the ground. You know much more about it than I do. I am afraid I shall have to defer to you."

Again we heard the bell downstairs, and a moment later a cheery voice, as Mrs. Woods met some one down in the foyer, asked, "How is the patient to-night?"

We could not catch the reply.

"Dr. Bryant, my physician," put in Haughton. "Don't go. I will assume the responsibility for your being here. Hello, Doctor. Why, I'm much the same to-night, thank you. At least no worse since I took your advice and went to bed."

Dr. Bryant was a bluff, hearty man, with the personal magnetism which goes with the making of a successful physician. He had mounted the stairs quietly but rapidly, evidently prepared to see us.

"Would you mind waiting in this little dressing room?" asked the doctor, motioning to another, smaller room adjoining.

He had taken from his pocket a little instrument with a dial face like a watch, which he attached to Haughton's wrist. "A pocket instrument to measure blood pressure," whispered Craig, as we entered the little room.

While the others were gathered about Haughton, we stood in the next room, out of earshot. Kennedy had leaned his elbow on a chiffonier. As he looked about the little room, more from force of habit than because he thought he might discover anything, Kennedy's eye rested on a glass tray on the top in which lay some pins, a collar button or two, which Haughton had apparently just taken off, and several other little unimportant articles.

Kennedy bent over to look at the glass tray more closely, a puzzled look crossed his face, and with a glance at the other room he gathered up the tray and its contents.

"Keep up a good courage," said Dr. Bryant. "You'll come out all right, Haughton." Then as he left the bedroom he added to us, "Gentlemen, I hope you will pardon me, but if you could postpone the remainder of your visit until a later day, I am sure you will find it more satisfactory."

There was an air of finality about the doctor, though nothing unpleasant in it. We followed him down the stairs, and as we did so, Felicie, who had been waiting in a reception room, appeared before the portieres, her earnest eyes fixed on his kindly face.

"Dr. Bryant," she appealed, "is he—is he, really—so badly?"

The Doctor, who had apparently known her all her life, reached down and took one of her hands, patting it with his own in a fatherly way. "Don't worry, little girl," he encouraged. "We are going to come out all right—all right."

She turned from him to us and, with a bright forced smile which showed the stuff she was made of, bade us good night.

Outside, the Doctor, apparently regretting that he had virtually forced us out, paused before his car. "Are you going down toward the station? Yes? I am going that far. I should be glad to drive you there."

Kennedy climbed into the front seat, leaving me in the rear where the wind wafted me their brief conversation as we sped down Woodbridge Avenue.

"What seems to be the trouble?" asked Craig.

"Very high blood pressure, for one thing," replied the Doctor frankly.

"For which the latest thing is the radium water cure, I suppose?" ventured Kennedy.

"Well, radioactive water is one cure for hardening of the arteries. But I didn't say he had hardening of the arteries. Still, he is taking the water, with good results. You are from the company?"

Kennedy nodded.

"It was the radium water that first interested him in it. Why, we found a pressure of 230 pounds, which is frightful, and we have brought it down to 150, not far from normal."

"Still that could have nothing to do with the sore on his neck," hazarded Kennedy.

The Doctor looked at him quickly, then ahead at the path of light which his motor shed on the road.

He said nothing, but I fancied that even he felt there was something strange in his silence over the new complication. He did not give Kennedy a chance to ask whether there were any other such sores.

"At any rate," he said, as he throttled down his engine with a flourish before the pretty little Glenclair station, "that girl needn't worry."

There was evidently no use in trying to extract anything further from him. He had said all that medical ethics or detective skill could get from him. We thanked him and turned to the ticket window to see how long we should have to wait.

"Either that doctor doesn't know what he is talking about or he is concealing something," remarked Craig, as we paced up and down the platform. "I am inclined to read the enigma in the latter way."

Nothing more passed between us during the journey back, and we hurried directly to the laboratory, late as it was. Kennedy had evidently been revolving something over and over in his mind, for the moment he had switched on the light, he unlocked one of his air-and dust-proof cabinets and took from it an instrument which he placed on a table before him.

It was a peculiar-looking instrument, like a round glass electric battery with a cylinder atop, smaller and sticking up like a safety valve. On that were an arm, a dial, and a lens fixed in such a way as to read the dial. I could not see what else the rather complicated little apparatus consisted of, but inside, when Kennedy brought near it the pole of a static electric machine two delicate thin leaves of gold seemed to fly wide apart when it was charged.

Kennedy had brought the glass tray near the thing. Instantly the leaves collapsed and he made a reading through the lens.

"What is it?" I asked.

"A radioscope," he replied, still observing the scale. "Really a very sensitive gold leaf electroscope, devised by one of the students of Madame Curie. This method of detection is far more sensitive even than the spectroscope."

"What does it mean when the leaves collapse?" I asked.

"Radium has been near that tray," he answered. "It is radioactive. I suspected it first when I saw that violet color. That is what radium does to that kind of glass. You see, if radium exists in a gram of inactive matter only to the extent of one in ten-thousand million parts its presence can be readily detected by this radioscope, and everything that has been rendered radioactive is the same. Ordinarily the air between the gold leaves is insulating. Bringing something radioactive near them renders the air a good conductor and the leaves fall under the radiation."

"Wonderful!" I exclaimed, marveling at the delicacy of it.

"Take radium water," he went on, "sufficiently impregnated with radium emanations to be luminous in the dark, like that water of Denison's. It would do the same. In fact all mineral waters and the so-called curarive muds like fango are slightly radioactive. There seems to be a little radium everywhere on earth that experiments have been made, even in the interiors of buildings. It is ubiquitous. We are surrounded and permeated by radiations—that soil out there on the campus, the air of this room, all. But," he added contemplatively, "there is something different about that tray. A lot of radium has been near that, and recently."

"How about that bandage about Haughton's neck?" I asked suddenly. "Do you think radium could have had anything to do with that?" "Well, as to burns, there is no particular immediate effect usually, and sometimes even up to two weeks or more, unless the exposure has been long and to a considerable quantity. Of course radium keeps itself three or four degrees warmer than other things about it constantly. But that isn't what does the harm. It is continually emitting little corpuscles, which I'll explain some other time, traveling all the way from twenty to one hundred and thirty thousand miles a second, and these corpuscles blister and corrode the flesh like quick-moving missiles bombarding it. The gravity of such lesions increases with the purity of the radium. For instance I have known an exposure of half an hour to a comparatively small quantity through a tube, a box and the clothes to produce a blister fifteen days later. Curie said he wouldn't trust himself in a room with a kilogram of it. It would destroy his eyesight, burn off his skin and kill him eventually. Why, even after a slight exposure your clothes are radioactive—the electroscope will show that."

He was still fumbling with the glass plate and the various articles on it.

"There's something very peculiar about all this," he muttered, almost to himself.

Tired by the quick succession of events of the past two days, I left Kennedy still experimenting in his laboratory and retired, still wondering when the real clue was to develop. Who could it have been who bore the tell-tale burn? Was the mark hidden by the bandage about Haughton's neck the brand of the stolen tubes? Or were there other marks on his body which we could not see?

No answer came to me, and I fell asleep and woke up without a radiation of light on the subject. Kennedy spent the greater part of the day still at work at his laboratory, performing some very delicate experiments. Finding nothing to do there, I went down to the Star office and spent my time reading the reports that came in from the small army of reporters who had been assigned to run down clues in the case which was the sensation of the moment. I have always felt my own lips sealed in such cases, until the time came that the story was complete and Kennedy released me from any further need of silence. The weird and impossible stories which came in not only to the Star but to the other papers surely did make passable copy in this instance, but with my knowledge of the case I could see that not one of them brought us a step nearer the truth.

One thing which uniformly puzzled the newspapers was the illness of Haughton and his enforced idleness at a time which was of so much importance to the company which he had promoted and indeed very largely financed. Then, of course, there was the romantic side of his engagement to Felicie Woods.

Just what connection Felicie Woods had with the radium robbery if any, I was myself unable quite to fathom. Still, that made no difference to the papers. She was pretty and therefore they published her picture, three columns deep, with Haughton and Denison, who were intimately concerned with the real loss in little ovals perhaps an inch across and two inches in the opposite dimension.

The late afternoon news editions had gone to press, and I had given up in despair, determined to go up to the laboratory and sit around idly watching Kennedy with his mystifying experiments, in preference to waiting for him to summon me.

I had scarcely arrived and settled myself to an impatient watch, when an automobile drove up furiously, and Denison himself, very excited, jumped out and dashed into the laboratory.

"What's the matter?" asked Kennedy, looking up from a test tube which he had been examining, with an air for all the world expressive of "Why so hot, little man?"

"I've had a threat," ejaculated Denison.

He laid on one of the laboratory tables a letter, without heading and without signature, written in a disguised hand, with an evident attempt to simulate the cramped script of a foreign penmanship.

"I know who did the Pittsburgh job. The same party is out to ruin Federal Radium. Remember Pittsburgh and be prepared!

"A STOCKHOLDER."

"Well?" demanded Kennedy, looking up.

"That can have only one meaning," asserted Denison.

"What is that?" inquired Kennedy coolly, as if to confirm his own interpretation.

"Why, another robbery—here in New York, of course."

"But who would do it?" I asked.

"Who?" repeated Denison. "Some one representing that European combine, of course. That is only part of the Trust method—ruin of competitors whom they cannot absorb."

"Then you have refused to go into the combine? You know who is backing it?"

"No—no," admitted Denison reluctantly. "We have only signified our intent to go it alone, as often as anyone either with or without authority has offered to buy us out. No, I do not even know who the people are. They never act in the open. The only hints I have ever received were through perfectly reputable brokers acting for others."

"Does Haughton know of this note?" asked Kennedy.

"Yes. As soon as I received it, I called him up."

"What did he say?"

"He said to disregard it. But—you know what condition he is in. I don't know what to do, whether to surround the office by a squad of detectives or remove the radium to a regular safety deposit vault, even at the loss of the emanation. Haughton has left it to me."

Suddenly the thought flashed across my mind that perhaps Haughton could act in this uninterested fashion because he had no fear of ruin either way. Might he not be playing a game with the combination in which he had protected himself so that he would win, no matter what happened?

"What shall I do?" asked Denison. "It is getting late."

"Neither," decided Kennedy.

Denison shook his head. "No," he said, "I shall have some one watch there, anyhow."



CHAPTER XV

THE ASPHYXIATING SAFE

Denison had scarcely gone to arrange for some one to watch the office that night, when Kennedy, having gathered up his radioscope and packed into a parcel a few other things from various cabinets, announced: "Walter, I must see that Miss Wallace, right away. Denison has already given me her address. Call a cab while I finish clearing up here. I don't like the looks of this thing, even if Haughton does neglect it."

We found Miss Wallace at a modest boarding-house in an old but still respectable part of the city. She was a very pretty girl, of the slender type, rather a business woman than one given much to amusement. She had been ill and was still ill. That was evident from the solicitous way in which the motherly landlady scrutinized two strange callers.

Kennedy presented a card from Denison, and she came down to the parlor to see us.

"Miss Wallace," began Kennedy, "I know it is almost cruel to trouble you when you are not feeling like office work, but since the robbery of the safe at Pittsburgh, there have been threats of a robbery of the New York office."

She started involuntarily, and it was evident, I thought, that she was in a very high-strung state.

"Oh," she cried, "why, the loss means ruin to Mr. Denison!"

There were genuine tears in her eyes as she said it.

"I thought you would be willing to aid us," pursued Kennedy sympathetically. "Now, for one thing, I want to be perfectly sure just how much radium the Corporation owns, or rather owned before the first robbery."

"The books will show it," she said simply.

"They will?" commented Kennedy. "Then if you will explain to me briefly just the system you used in keeping account of it, perhaps I need not trouble you any more."

"I'll go down there with you," she answered bravely. "I'm better to-day, anyhow, I think."

She had risen, but it was evident that she was not as strong as she wanted us to think.

"The least I can do is to make it as easy as possible by going in a car," remarked Kennedy, following her into the hall where there was a telephone.

The hallway was perfectly dark, yet as she preceded us I could see that the diamond pin which held her collar in the back sparkled as if a lighted candle had been brought near it. I had noticed in the parlor that she wore a handsome tortoiseshell comb set with what I thought were other brilliants, but when I looked I saw now that there was not the same sparkle to the comb which held her dark hair in a soft mass. I noticed these little things at the time, not because I thought they had any importance, but merely by chance, wondering at the sparkle of the one diamond which had caught my eye.

"What do you make of her?" I asked as Kennedy finished telephoning.

"A very charming and capable girl," he answered noncommittally.

"Did you notice how that diamond in her neck sparkled?" I asked quickly.

He nodded. Evidently it had attracted his attention, too.

"What makes it?" I pursued.

"Well, you know radium rays will make a diamond fluoresce in the dark."

"Yes," I objected, "but how about those in the comb?"

"Paste, probably," he answered tersely, as we heard her foot on the landing. "The rays won't affect paste."

It was indeed a shame to take advantage of Miss Wallace's loyalty to Denison, but she was so game about it that I knew only the utmost necessity on Kennedy's part would have prompted him to do it. She had a key to the office so that it was not necessary to wait for Denison, if indeed we could have found him.

Together she and Kennedy went over the records. It seemed that there were in the safe twenty-five platinum tubes of one hundred milligrams each, and that there had been twelve of the same amount at Pittsburgh. Little as it seemed in weight it represented a fabulous fortune.

"You have not the combination?" inquired Kennedy.

"No. Only Mr. Denison has that. What are you going to do to protect the safe to-night?" she asked.

"Nothing especially," evaded Kennedy.

"Nothing?" she repeated in amazement.

"I have another plan," he said, watching her intently. "Miss Wallace, it was too much to ask you to come down here. You are ill."

She was indeed quite pale, as if the excitement had been an overexertion.

"No, indeed," she persisted. Then, feeling her own weakness, she moved toward the door of Denison's office where there was a leather couch. "Let me rest here a moment. I do feel queer. I—"

She would have fallen if he had not sprung forward and caught her as she sank to the floor, overcome by the exertion.

Together we carried her in to the couch, and as we did so the comb from her hair clattered to the floor.

Craig threw open the window, and bathed her face with water until there was a faint flutter of the eyelids.

"Walter," he said, as she began to revive, "I leave her to you. Keep her quiet for a few moments. She has unintentionally given me just the opportunity I want."

While she was yet hovering between consciousness and unconsciousness on the couch, he had unwrapped the package which he had brought with him. For a moment he held the comb which she had dropped near the radioscope. With a low exclamation of surprise he shoved it into his pocket.

Then from the package he drew a heavy piece of apparatus which looked as if it might be the motor part of an electric fan, only in place of the fan he fitted a long, slim, vicious-looking steel bit. A flexible wire attached the thing to the electric light circuit and I knew that it was an electric drill. With his coat off he tugged at the little radium safe until he had moved it out, then dropped on his knees behind it and switched the current on in the electric drill.

It was a tedious process to drill through the steel of the outer casing of the safe and it was getting late. I shut the door to the office so that Miss Wallace could not see.

At last by the cessation of the low hum of the boring, I knew that he had struck the inner lead lining. Quietly I opened the door and stepped out. He was injecting something from an hermetically sealed lead tube into the opening he had made and allowing it to run between the two linings of lead and steel. Then using the tube itself he sealed the opening he had made and dabbed a little black over it.

Quickly he shoved the safe back, then around it concealed several small coils with wires also concealed and leading out through a window to a court.

"We'll catch the fellow this time," he remarked as he worked. "If you ever have any idea, Walter, of going into the burglary business, it would be well to ascertain if the safes have any of these little selenium cells as suggested by my friend, Mr. Hammer, the inventor. For by them an alarm can be given miles away the moment an intruder's bull's-eye falls on a hidden cell sensitive to light."

While I was delegated to take Miss Wallace home, Kennedy made arrangements with a small shopkeeper on the ground floor of a building that backed up on the court for the use of his back room that night, and had already set up a bell actuated by a system of relays which the weak current from the selenium cells could operate.

It was not until nearly midnight that he was ready to leave the laboratory again, where he had been busily engaged in studying the tortoiseshell comb which Miss Wallace in her weakness had forgotten.

The little shopkeeper let us in sleepily and Kennedy deposited a large round package on a chair in the back of the shop, as well as a long piece of rubber tubing. Nothing had happened so far.

As we waited the shopkeeper, now wide awake and not at all unconvinced that we were bent on some criminal operation, hung around. Kennedy did not seem to care. He drew from his pocket a little shiny brass instrument in a lead case, which looked like an abbreviated microscope.

"Look through it," he said, handing it to me.

I looked and could see thousands of minute sparks.

"What is it?" I asked.

"A spinthariscope. In that it is possible to watch the bombardment of the countless little corpuscles thrown off by radium, as they strike on the zinc blende crystal which forms the base. When radium was originally discovered, the interest was merely in its curious properties, its power to emit invisible rays which penetrated solid substances and rendered things fluorescent, of expending energy without apparent loss.

"Then came the discovery," he went on, "of its curative powers. But the first results were not convincing. Still, now that we know the reasons why radium may be dangerous and how to protect ourselves against them we know we possess one of the most wonderful of curative agencies."

I was thinking rather of the dangers than of the beneficence of radium just now, but Kennedy continued.

"It has cured many malignant growths that seemed hopeless, brought back destroyed cells, exercised good effects in diseases of the liver and intestines and even the baffling diseases of the arteries. The reason why harm, at first, as well as good came, is now understood. Radium emits, as I told you before, three kinds of rays, the alpha, beta, and gamma rays, each with different properties. The emanation is another matter. It does not concern us in this case, as you will see."

Fascinated as I was by the mystery of the case, I began to see that he was gradually arriving at an explanation which had baffled everyone else.

"Now, the alpha rays are the shortest," he launched forth, "in length let us say one inch. They exert a very destructive effect on healthy tissue. That is the cause of injury. They are stopped by glass, aluminum and other metals, and are really particles charged with positive electricity. The beta rays come next, say, about an inch and a half. They stimulate cell growth. Therefore they are dangerous in cancer, though good in other ways. They can be stopped by lead, and are really particles charged with negative electricity. The gamma rays are the longest, perhaps three inches long, and it is these rays which effect cures, for they check the abnormal and stimulate the normal cells. They penetrate lead. Lead seems to filter them out from the other rays. And at three inches the other rays don't reach, anyhow. The gamma rays are not charged with electricity at all, apparently."

He had brought a little magnet near the spinthariscope. I looked into it.

"A magnet," he explained, "shows the difference between the alpha, beta, and gamma rays. You see those weak and wobbly rays that seem to fall to one side? Those are the alpha rays. They have a strong action, though, on tissues and cells. Those falling in the other direction are the beta rays. The gamma rays seem to flow straight."

"Then it is the alpha rays with which we are concerned mostly now?" I queried, looking up.

"Exactly. That is why, when radium is unprotected or insufficiently protected and comes too near, it is destructive of healthy cells, produces burns, sores, which are most difficult to heal. It is with the explanation of such sores that we must deal."

It was growing late. We had waited patiently now for some time. Kennedy had evidently reserved this explanation, knowing we should have to wait. Still nothing happened.

Added to the mystery of the violet-colored glass plate was now that of the luminescent diamond. I was about to ask Kennedy point- blank what he thought of them, when suddenly the little bell before us began to buzz feebly under the influence of a current.

I gave a start. The faithful little selenium cell burglar alarm had done the trick. I knew that selenium was a good conductor of electricity in the light, poor in the dark. Some one had, therefore, flashed a light on one of the cells in the Corporation office. It was the moment for which Kennedy had prepared.

Seizing the round package and the tubing, he dashed out on the street and around the corner. He tried the door opening into the Radium Corporation hallway. It was closed, but unlocked. As it yielded and we stumbled in, up the old worn wooden stairs of the building, I knew that there must be some one there.

A terrific, penetrating, almost stunning odor seemed to permeate the air even in the hall.

Kennedy paused at the door of the office, tried it, found it unlocked, but did not open it.

"That smell is ethyldichloracetate," he explained. "That was what I injected into the air cushion of that safe between the two linings. I suppose my man here used an electric drill. He might have used thermit or an oxyacetylene blowpipe for all I would care. These fumes would discourage a cracksman from 'soup' to nuts," he laughed, thoroughly pleased at the protection modern science had enabled him to devise.

As we stood an instant by the door, I realized what had happened. We had captured our man. He was asphyxiated!

Yet how were we to get to him? Would Craig leave him in there, perhaps to die? To go in ourselves meant to share his fate, whatever might be the effect of the drug.

Kennedy had torn the wrapping off the package. From it he drew a huge globe with bulging windows of glass in the front and several curious arrangements on it at other points. To it he fitted the rubber tubing and a little pump. Then he placed the globe over his head, like a diver's helmet, and fastened some air-tight rubber arrangement about his neck and shoulders.

"Pump, Walter I" he shouted. "This is an oxygen helmet such as is used in entering mines filled with deadly gases."

Without another word he was gone into the blackness of the noxious stifle which filled the Radium Corporation office since the cracksman had struck the unexpected pocket of rapidly evaporating stuff.

I pumped furiously.

Inside I could hear him blundering around. What was he doing?

He was coming back slowly. Was he, too, overcome?

As he emerged into the darkness of the hallway where I myself was almost sickened, I saw that he was dragging with him a limp form.

A rush of outside air from the street door seemed to clear things a little. Kennedy tore off the oxygen helmet and dropped down on his knees beside the figure, working its arms in the most approved manner of resuscitation.

"I think we can do it without calling on the pulmotor," he panted. "Walter, the fumes have cleared away enough now in the outside office. Open a window—and keep that street door open, too."

I did so, found the switch and turned on the lights.

It was Denison himself!

For many minutes Kennedy worked over him. I bent down, loosened his collar and shirt, and looked eagerly at his chest for the tell-tale marks of the radium which I felt sure must be there. There was not even a discoloration.

Not a word was said, as Kennedy brought the stupefied little man around.

Denison, pale, shaken, was leaning back now in a big office chair, gasping and holding his head.

Kennedy, before him, reached down into his pocket and handed him the spinthariscope.

"You see that?" he demanded.

Denison looked through the eyepiece.

"Wh—where did you get so much of it?" he asked, a queer look on his face.

"I got that bit of radium from the base of the collar button of Hartley Haughton," replied Kennedy quietly, "a collar button which some one intimate with him had substituted for his own, bringing that deadly radium with only the minutest protection of a thin strip of metal close to the back of his neck, near the spinal cord and the medulla oblongata which controls blood pressure. That collar button was worse than the poisoned rings of the Borgias. And there is more radium in the pretty gift of a tortoiseshell comb with its paste diamonds which Miss Wallace wore in her hair. Only a fraction of an inch, not enough to cut off the deadly alpha rays, protected the wearers of those articles."

He paused a moment, while surging through my mind came one after another the explanations of the hitherto inexplicable. Denison seemed almost to cringe in the chair, weak already from the fumes.

"Besides," went on Kennedy remorselessly, "when I went in there to drag you out, I saw the safe open. I looked. There was nothing in those pretty platinum tubes, as I suspected. European trust—bah! All the cheap devices of a faker with a confederate in London to send a cablegram—and another in New York to send a threatening letter."

Kennedy extended an accusing forefinger at the man cowering before him.

"This is nothing but a get-rich-quick scheme, Denison. There never was a milligram of radium in the Poor Little Rich Valley, not a milligram here in all the carefully kept reports of Miss Wallace— except what was bought outside by the Corporation with the money it collected from its dupes. Haughton has been fleeced. Miss Wallace, blinded by her loyalty to you—you will always find such a faithful girl in such schemes as yours—has been fooled.

"And how did you repay it? What was cleverer, you said to yourself, than to seem to be robbed of what you never had, to blame it on a bitter rival who never existed? Then to make assurance doubly sure, you planned to disable, perhaps get rid of the come-on whom you had trimmed, and the faithful girl whose eyes you had blinded to your gigantic swindle.

"Denison," concluded Kennedy, as the man drew back, his very face convicting him, "Denison, you are the radium robber—robber in another sense!"



CHAPTER XVI

THE DEAD LINE

Maiden Lane, no less than Wall Street, was deeply interested in the radium case. In fact, it seemed that one case in this section of the city led to another.

Naturally, the Star and the other papers made much of the capture of Denison. Still, I was not prepared for the host of Maiden Lane cases that followed. Many of them were essentially trivial. But one proved to be of extreme importance.

"Professor Kennedy, I have just heard of your radium case, and I— I feel that I can—trust you."

There was a note of appeal in the hesitating voice of the tall, heavily veiled woman whose card had been sent up to us with a nervous "Urgent" written across its face.

It was very early in the morning, but our visitor was evidently completely unnerved by some news which she had just received and which had sent her posting to see Craig.

Kennedy met her gaze directly with a look that arrested her involuntary effort to avoid it again. She must have read in his eyes more than in his words that she might trust him.

"I—I have a confession to make," she faltered.

"Please sit down, Mrs. Moulton," he said simply. "It is my business to receive confidences—and to keep them."

She sank into, rather than sat down in, the deep leather rocker beside his desk, and now for the first time raised her veil.

Antoinette Moulton was indeed stunning, an exquisite creature with a wonderful charm of slender youth, brightness of eye and brunette radiance.

I knew that she had been on the musical comedy stage and had had a rapid rise to a star part before her marriage to Lynn Moulton, the wealthy lawyer, almost twice her age. I knew also that she had given up the stage, apparently without a regret. Yet there was something strange about the air of secrecy of her visit. Was there a hint in it of a disagreement between the Moultons, I wondered, as I waited while Kennedy reassured her.

Her distress was so unconcealed that Craig, for the moment, laid aside his ordinary inquisitorial manner. "Tell me just as much or just as little as you choose, Mrs. Moulton," he added tactfully. "I will do my best."

A look almost of gratitude crossed her face.

"When we were married," she began again, "my husband gave me a beautiful diamond necklace. Oh, it must have been worth a hundred thousand dollars easily. It was splendid. Everyone has heard of it. You know, Lynn—er—Mr. Moulton, has always been an enthusiastic collector of jewels."

She paused again and Kennedy nodded reassuringly. I knew the thought in his mind. Moulton had collected one gem that was incomparable with all the hundred thousand dollar necklaces in existence.

"Several months ago." she went on rapidly, still avoiding his eyes and forcing the words from her reluctant lips, "I—oh, I needed money—terribly."

She had risen and faced him, pressing her daintily gloved hands together in a little tremble of emotion which was none the less genuine because she had studied the art of emotion.

"I took the necklace to a jeweler, Herman Schloss, of Maiden Lane, a man with whom my husband had often had dealings and whom I thought I could trust. Under a promise of secrecy he loaned me fifty thousand dollars on it and had an exact replica in paste made by one of his best workmen. This morning, just now, Mr. Schloss telephoned me that his safe had been robbed last night. My necklace is gone!"

She threw out her hands in a wildly appealing gesture.

"And if Lynn finds that the necklace in our wall safe is of paste- -as he will find, for he is an expert in diamonds—oh—what shall I do? Can't you—can't you find my necklace?"

Kennedy was following her now eagerly. "You were blackmailed out of the money?" he queried casually, masking his question.

There was a sudden, impulsive drooping of her mouth, an evasion and keen wariness in her eyes. "I can't see that that has anything to do with the robbery," she answered in a low voice.

"I beg your pardon," corrected Kennedy quickly. "Perhaps not. I'm sorry. Force of habit, I suppose. You don't know anything more about the robbery?"

"N—no, only that it seems impossible that it could have happened in a place that has the wonderful burglar alarm protection that Mr. Schloss described to me."

"You know him pretty well?"

"Only through this transaction," she replied hastily. "I wish to heaven I had never heard of him."

The telephone rang insistently.

"Mrs. Moulton," said Kennedy, as he returned the receiver to the hook, "it may interest you to know that the burglar alarm company has just called me up about the same case. If I had need of an added incentive, which I hope you will believe I have not, that might furnish it. I will do my best," he repeated.

"Thank you—a thousand times," she cried fervently, and, had I been Craig, I think I should have needed no more thanks than the look she gave him as he accompanied her to the door of our apartment.

It was still early and the eager crowds were pushing their way to business through the narrow network of downtown streets as Kennedy and I entered a large office on lower Broadway in the heart of the jewelry trade and financial district.

"One of the most amazing robberies that has ever been attempted has been reported to us this morning," announced James McLear, manager of the Hale Electric Protection, adding with a look half of anxiety, half of skepticism, "that is, if it is true."

McLear was a stocky man, of powerful build and voice and a general appearance of having been once well connected with the city detective force before an attractive offer had taken him into this position of great responsibility.

"Herman Schloss, one of the best known of Maiden Lane jewelers," he continued, "has been robbed of goods worth two or three hundred thousand dollars—and in spite of every modern protection. So that you will get it clearly, let me show you what we do here."

He ushered us into a large room, on the walls of which were hundreds of little indicators. From the front they looked like rows of little square compartments, tier on tier, about the size of ordinary post office boxes. Closer examination showed that each was equipped with a delicate needle arranged to oscillate backward and forward upon the very minutest interference with the electric current. Under the boxes, each of which bore a number, was a series of drops and buzzers numbered to correspond with the boxes.

"In nearly every office in Maiden Lane where gems and valuable jewelry are stored," explained McLear, "this electrical system of ours is installed. When the safes are closed at night and the doors swung together, a current of electricity is constantly shooting around the safes, conducted by cleverly concealed wires. These wires are picked up by a cable system which finds its way to this central office. Once here, the wires are safeguarded in such manner that foreign currents from other wires or from lightning cannot disturb the system."

We looked with intense interest at this huge electrical pulse that felt every change over so vast and rich an area.

"Passing a big dividing board," he went on, "they are distributed and connected each in its place to the delicate tangent galvanometers and sensitive indicators you see in this room. These instantly announce the most minute change in the working of the current, and each office has a distinct separate metallic circuit. Why, even a hole as small as a lead pencil in anything protected would sound the alarm here."

Kennedy nodded appreciatively.

"You see," continued McLear, glad to be able to talk to one who followed him so closely, "it is another evidence of science finding for us greater security in the use of a tiny electric wire than in massive walls of steel and intricate lock devices. But here is a case in which, it seems, every known protection has failed. We can't afford to pass that by. If we have fallen down we want to know how, as well as to catch the burglar."

"How are the signals given?" I asked.

"Well, when the day's business is over, for instance, Schloss would swing the heavy safe doors together and over them place the doors of a wooden cabinet. That signals an alarm to us here. We answer it and if the proper signal is returned, all right. After that no one can tamper with the safe later in the night without sounding an alarm that would bring a quick investigation."

"But suppose that it became necessary to open the safe before the next morning. Might not some trusted employee return to the office, open it, give the proper signals and loot the safe?"

"No indeed," he answered confidently. "The very moment anyone touches the cabinet, the alarm is sounded. Even if the proper code signal is returned, it is not sufficient. A couple of our trusted men from the central office hustle around there anyhow and they don't leave until they are satisfied that everything is right. We have the authorized signatures on hand of those who are supposed to open the safe and a duplicate of one of them must be given or there is an arrest."

McLear considered for a moment.

"For instance, Schloss, like all the rest, was assigned a box in which was deposited a sealed envelope containing a key to the office and his own signature, in this case, since he alone knew the combination. Now, when an alarm is sounded, as it was last night, and the key removed to gain entrance to the office, a record is made and the key has to be sealed up again by Schloss. A report is also submitted showing when the signals are received and anything else that is worth recording. Last night our men found nothing wrong, apparently. But this morning we learn of the robbery."

"The point is, then," ruminated Kennedy, "what happened in the interval between the ringing of the alarm and the arrival of the special officers? I think I'll drop around and look Schloss' place over," he added quietly, evidently eager to begin at the actual scene of the crime.

On the door of the office to which McLear took us was one of those small blue plates which chance visitors to Maiden Lane must have seen often. To the initiated—be he crook or jeweler—this simple sign means that the merchant is a member of the Jewelers' Security Alliance, enough in itself, it would seem, to make the boldest burglar hesitate. For it is the motto of this organization to "get" the thief at any cost and at any time. Still, it had not deterred the burglar in this instance.

"I know people are going to think it is a fake burglary," exclaimed Schloss, a stout, prosperous-looking gem broker, as we introduced ourselves. "But over two hundred thousands dollars' worth of stones are gone," he half groaned. "Think of it, man," he added, "one of the greatest robberies since the Dead Line was established. And if they can get away with it, why, no one down here is protected any more. Half a billion dollars in jewels in Maiden Lane and John Street are easy prey for the cracksmen!"

Staggering though the loss must have been to him, he had apparently recovered from the first shock of the discovery and had begun the fight to get back what had been lost.

It was, as McLear had intimated, a most amazing burglary, too. The door of Schloss' safe was open when Kennedy and I arrived and found the excited jeweler nervously pacing the office. Surrounding the safe, I noticed a wooden framework constructed in such a way as to be a part of the decorative scheme of the office.

Schloss banged the heavy doors shut.

"There, that's just how it was—shut as tight as a drum. There was absolutely no mark of anyone tampering with the combination lock. And yet the safe was looted!"

"How did you discover it?" asked Craig. "I presume you carry burglary insurance?"

Schloss looked up quickly. "That's what I expected as a first question. No, I carried very little insurance. You see, I thought the safe, one of those new chrome steel affairs, was about impregnable. I never lost a moment's sleep over it; didn't think it possible for anyone to get into it. For, as you see, it is completely wired by the Hale Electric Protection—that wooden framework about it. No one could touch that when it was set without jangling a bell at the central office which would send men scurrying here to protect the place."

"But they must have got past it," suggested Kennedy.

"Yes—they must have. At least this morning I received the regular Hale report. It said that their wires registered last night as though some one was tampering with the safe. But by the time they got around, in less than five minutes, there was no one here, nothing seemed to be disturbed. So they set it down to induction or electrolysis, or something the matter with the wires. I got the report the first thing when I arrived here with my assistant, Muller."

Kennedy was on his knees, going over the safe with a fine brush and some powder, looking now and then through a small magnifying glass.

"Not a finger print," he muttered. "The cracksman must have worn gloves. But how did he get in? There isn't a mark of 'soup' having been used to blow it up, nor of a 'can-opener' to rip it open, if that were possible, nor of an electric or any other kind of drill."

"I've read of those fellows who burn their way in," said Schloss.

"But there is no hole," objected Kennedy, "not a trace of the use of thermit to burn the way in or of the oxyacetylene blowpipe to cut a piece out. Most extraordinary," he murmured.

"You see," shrugged Schloss, "everyone will say it must have been opened by one who knew the combination. But I am the only one. I have never written it down or told anyone, not even Muller. You understand what I am up against?"

"There's the touch system," I suggested. "You remember, Craig, the old fellow who used to file his finger tips to the quick until they were so sensitive that he could actually feel when he had turned the combination to the right plunger? Might not that explain the lack of finger prints also?" I added eagerly.

"Nothing like that in this case, Walter," objected Craig positively. "This fellow wore gloves, all right. No, this safe has been opened and looted by no ordinarily known method. It's the most amazing case I ever saw in that respect—almost as if we had a cracksman in the fourth dimension to whom the inside of a closed cube is as accessible as is the inside of a plane square to us three dimensional creatures. It is almost incomprehensible."

I fancied I saw Schloss' face brighten as Kennedy took this view. So far, evidently, he had run across only skepticism.

"The stones were unset?" resumed Craig.

"Mostly. Not all."

"You would recognize some of them if you saw them?"

"Yes indeed. Some could be changed only by re-cutting. Even some of those that were set were of odd cut and size—some from a diamond necklace which belonged to a—"

There was something peculiar in both his tone and manner as he cut short the words.

"To whom?" asked Kennedy casually.

"Oh, once to a well-known woman in society," he said carefully. "It is mine, though, now—at least it was mine. I should prefer to mention no names. I will give a description of the stones."

"Mrs. Lynn Moulton, for instance?" suggested Craig quietly.

Schloss jumped almost as if a burglar alarm had sounded under his very ears. "How did you know? Yes—but it was a secret. I made a large loan on it, and the time has expired."

"Why did she need money so badly?" asked Kennedy.

"How should I know?" demanded Schloss.

Here was a deepening mystery, not to be elucidated by continuing this line of inquiry with Schloss, it seemed.



CHAPTER XVII

THE PASTE REPLICA

Carefully Craig was going over the office. Outside of the safe, there had apparently been nothing of value. The rest of the office was not even wired, and it seemed to have been Schloss' idea that the few thousands of burglary insurance amply protected him against such loss. As for the safe, its own strength and the careful wiring might well have been considered quite sufficient under any hitherto to-be-foreseen circumstances.

A glass door, around the bend of a partition, opened from the hallway into the office and had apparently been designed with the object of making visible the safe so that anyone passing might see whether an intruder was tampering with it.

Kennedy had examined the door, perhaps in the expectation of finding finger prints there, and was passing on to other things, when a change in his position caused his eye to catch a large oval smudge on the glass, which was visible when the light struck it at the right angle. Quickly he dusted it over with the powder, and brought out the detail more clearly. As I examined it, while Craig made preparations to cut out the glass to preserve it, it seemed to contain a number of minute points and several more or less broken parallel lines. The edges gradually trailed off into an indistinct faintness.

Business, naturally, was at a standstill, and as we were working near the door, we could see that the news of Schloss' strange robbery had leaked out and was spreading rapidly. Scores of acquaintances in the trade stopped at the door to inquire about the rumor.

To each, it seemed that Morris Muller, the working jeweler employed by Schloss, repeated the same story.

"Oh," he said, "it is a big loss—yes—but big as it is, it will not break Mr. Schloss. And," he would add with the tradesman's idea of humor, "I guess he has enough to play a game of poker— eh?"

"Poker?" asked Kennedy smiling. "Is he much of a player?"

"Yes. Nearly every night with his friends he plays."

Kennedy made a mental note of it. Evidently Schloss trusted Muller implicitly. He seemed like a partner, rather than an employee, even though he had not been entrusted with the secret combination.

Outside, we ran into city detective Lieutenant Winters, the officer who was stationed at the Maiden Lane post, guarding that famous section of the Dead Line established by the immortal Byrnes at Fulton Street, below which no crook was supposed to dare even to be seen. Winters had been detailed on the case.

"You have seen the safe in there?" asked Kennedy, as he was leaving to carry on his investigation elsewhere.

Winters seemed to be quite as skeptical as Schloss had intimated the public would be. "Yes," he replied, "there's been an epidemic of robbery with the dull times—people who want to collect their burglary insurance, I guess."

"But," objected Kennedy, "Schloss carried so little."

"Well, there was the Hale Protection. How about that?"

Craig looked up quickly, unruffled by the patronizing air of the professional toward the amateur detective.

"What is your theory?" he asked. "Do you think he robbed himself?"

Winters shrugged his shoulders. "I've been interested in Schloss for some time," he said enigmatically. "He has had some pretty swell customers. I'll keep you wised up, if anything happens," he added in a burst of graciousness, walking off.

On the way to the subway, we paused again to see McLear.

"Well," he asked, "what do you think of it, now?"

"All most extraordinary," ruminated Craig. "And the queerest feature of all is that the chief loss consists of a diamond necklace that belonged once to Mrs. Antoinette Moulton."

"Mrs. Lynn Moulton?" repeated McLear.

"The same," assured Kennedy.

McLear appeared somewhat puzzled. "Her husband is one of our old subscribers," he pursued. "He is a lawyer on Wall Street and quite a gem collector. Last night his safe was tampered with, but this morning he reports no loss. Not half an hour ago he had us on the wire congratulating us on scaring off the burglars, if there had been any."

"What is your opinion," I asked. "Is there a gang operating?"

"My belief is," he answered, reminiscently of his days on the detective force, "that none of the loot will be recovered until they start to 'fence' it. That would be my lay—to look for the fence. Why, think of all the big robberies that have been pulled off lately. Remember," he went on, "the spoils of a burglary consist generally of precious stones. They are not currency. They must be turned into currency—or what's the use of robbery?

"But merely to offer them for sale at an ordinary jeweler's would be suspicious. Even pawnbrokers are on the watch. You see what I am driving at? I think there is a man or a group of men whose business it is to pay cash for stolen property and who have ways of returning gems into the regular trade channels. In all these robberies we get a glimpse of as dark and mysterious a criminal as has ever been recorded. He may be—anybody. About his legitimacy, I believe, no question has ever been raised. And, I tell you, his arrest is going to create a greater sensation than even the remarkable series of robberies that he has planned or made possible. The question is, to my mind, who is this fence?"

McLear's telephone rang and he handed the instrument to Craig.

"Yes, this is Professor Kennedy," answered Craig. "Oh, too bad you've had to try all over to get me. I've been going from one place to another gathering clues and have made good progress, considering I've hardly started. Why—what's the matter? Really?"

An interval followed, during which McLear left to answer a personal call on another wire.

As Kennedy hung up the receiver, his face wore a peculiar look. "It was Mrs. Moulton," he blurted out. "She thinks that her husband has found out that the necklace is paste."

"How?" I asked.

"The paste replica is gone from her wall safe in the Deluxe."

I turned, startled at the information. Even Kennedy himself was perplexed at the sudden succession of events. I had nothing to say.

Evidently, however, his rule was when in doubt play a trump, for, twenty minutes later found us in the office of Lynn Moulton, the famous corporation lawyer, in Wall Street.

Moulton was a handsome man of past fifty with a youthful face against his iron gray hair and mustache, well dressed, genial, a man who seemed keenly in love with the good things of life.

"It is rumored," began Kennedy, "that an attempt was made on your safe here at the office last night."

"Yes," he admitted, taking off his glasses and polishing them carefully. "I suppose there is no need of concealment, especially as I hear that a somewhat similar attempt was made on the safe of my friend Herman Schloss in Maiden Lane."

"You lost nothing?"

Moulton put his glasses on and looked Kennedy in the face frankly.

"Nothing, fortunately," he said, then went on slowly. "You see, in my later years, I have been something of a collector of precious stones myself. I don't wear them, but I have always taken the keenest pleasure in owning them and when I was married it gave me a great deal more pleasure to have them set in rings, pendants, tiaras, necklaces, and other forms for my wife."

He had risen, with the air of a busy man who had given the subject all the consideration he could afford and whose work proceeded almost by schedule. "This morning I found my safe tampered with, but, as I said, fortunately something must have scared off the burglars."

He bowed us out politely. What was the explanation, I wondered. It seemed, on the face of things, that Antoinette Moulton feared her husband. Did he know something else already, and did she know he knew? To all appearances he took it very calmly, if he did know. Perhaps that was what she feared, his very calmness.

"I must see Mrs. Moulton again," remarked Kennedy, as we left.

The Moultons lived, we found, in one of the largest suites of a new apartment hotel, the Deluxe, and in spite of the fact that our arrival had been announced some minutes before we saw Mrs. Moulton, it was evident that she had been crying hysterically over the loss of the paste jewels and what it implied.

"I missed it this morning, after my return from seeing you," she replied in answer to Craig's inquiry, then added, wide-eyed with alarm, "What shall I do? He must have opened the wall safe and found the replica. I don't dare ask him point-blank."

"Are you sure he did it?" asked Kennedy, more, I felt, for its moral effect on her than through any doubt in his own mind.

"Not sure. But then the wall safe shows no marks, and the replica is gone."

"Might I see your jewel case?" he asked.

"Surely. I'll get it. The wall safe is in Lynn's room. I shall probably have to fuss a long time with the combination."

In fact she could not have been very familiar with it for it took several minutes before she returned. Meanwhile, Kennedy, who had been drumming absently on the arms of his chair, suddenly rose and walked quietly over to a scrap basket that stood beside an escritoire. It had evidently just been emptied, for the rooms must have been cleaned several hours before. He bent down over it and picked up two scraps of paper adhering to the wicker work. The rest had evidently been thrown away.

I bent over to read them. One was:

—rest Nettie— —dying to see—

The other read:

—cherche to-d —love and ma —rman.

What did it mean? Hastily, I could fill in "Dearest Nettie," and "I am dying to see you." Kennedy added, "The Recherche to-day," that being the name of a new apartment uptown, as well as "love and many kisses." But "—rman"—what did that mean? Could it be Herman—Herman Schloss?

She was returning and we resumed our seats quickly.

Kennedy took the jewel case from her and examined it carefully. There was not a mark on it.

"Mrs. Moulton," he said slowly, rising and handing it back to her, "have you told me all?"

"Why—yes," she answered.

Kennedy shook his head gravely.

"I'm afraid not. You must tell me everything."

"No—no," she cried vehemently, "there is nothing more."

We left and outside the Deluxe he paused, looked about, caught sight of a taxicab and hailed it.

"Where?" asked the driver.

"Across the street," he said, "and wait. Put the window in back of you down so I can talk. I'll tell you where to go presently. Now, Walter, sit back as far as you can. This may seem like an underhand thing to do, but we've got to get what that woman won't tell us or give up the case."

Perhaps half an hour we waited, still puzzling over the scraps of paper. Suddenly I felt a nudge from Kennedy. Antoinette Moulton was standing in the doorway across the street. Evidently she preferred not to ride in her own car, for a moment later she entered a taxicab.

"Follow that black cab," said Kennedy to our driver.

Sure enough, it stopped in front of the Recherche Apartments and Mrs. Moulton stepped out and almost ran in.

We waited a moment, then Kennedy followed. The elevator that had taken her up had just returned to the ground floor.

"The same floor again," remarked Kennedy, jauntily stepping in and nodding familiarly to the elevator boy.

Then he paused suddenly, looked at his watch, fixed his gaze thoughtfully on me an instant, and exclaimed. "By George—no. I can't go up yet. I clean forgot that engagement at the hotel. One moment, son. Let us out. We'll be back again."

Considerably mystified, I followed him to the sidewalk.

"You're entitled to an explanation," he laughed catching my bewildered look as he opened the cab door. "I didn't want to go up now while she is there, but I wanted to get on good terms with that boy. We'll wait until she comes down, then go up."

"Where?" I asked.

"That's what I am going through all this elaborate preparation to find out. I have no more idea than you have."

It could not have been more than twenty minutes later when Mrs. Moulton emerged rather hurriedly, and drove away.

While we had been waiting I had observed a man on the other side of the street who seemed unduly interested in the Recherche, too, for he had walked up and down the block no less than six times. Kennedy saw him, and as he made no effort to follow Mrs. Moulton, Kennedy did not do so either. In fact a little quick glance which she had given at our cab had raised a fear that she might have discovered that she was being followed.

Kennedy and I paid off our cabman and sauntered into the Recherche in the most debonair manner we could assume.

"Now, son, we'll go up," he said to the boy who, remembering us, and now not at all clear in his mind that he might not have seen us before that, whisked us to the tenth floor.

"Let me see," said Kennedy, "it's number one hundred and—er—-"

"Three," prompted the boy.

He pressed the buzzer and a neatly dressed colored maid responded.

"I had an appointment here with Mrs. Moulton this morning," remarked Kennedy.

"She has just gone," replied the maid, off her guard.

"And was to meet Mr. Schloss here in half an hour," he added quickly.

It was the maid's turn to look surprised.

"I didn't think he was to be here," she said. "He's had some—"

"Trouble at the office," supplied Kennedy. "That's what it was about. Perhaps he hasn't been able to get away yet. But I had the appointment. Ah, I see a telephone in the hall. May I?"

He had stepped politely in, and by dint of cleverly keeping his finger on the hook in the half light, he carried on a one-sided conversation with himself long enough to get a good chance to look about.

There was an air of quiet and refinement about the apartment in the Recherche. It was darkened to give the little glowing electric bulbs in their silken shades a full chance to simulate right. The deep velvety carpets were noiseless to the foot, and the draperies, the pictures, the bronzes, all bespoke taste.

But the chief objects of interest to Craig were the little square green baize-covered tables on one of which lay neatly stacked a pile of gilt-edged cards and a mahogany box full of ivory chips of red, white and blue.

It was none of the old-time gambling places, like Danfield's, with its steel door which Craig had once cut through with an oxyacetylene blowpipe in order to rescue a young spendthrift from himself.

Kennedy seemed perfectly well satisfied merely with a cursory view of the place, as he hung up the receiver and thanked the maid politely for allowing him to use it.

"This is up-to-date gambling in cleaned-up New York," he remarked as we waited for the elevator to return for us. "And the worst of it all is that it gets the women as well as the men. Once they are caught in the net, they are the most powerful lure to men that the gamblers have yet devised."

We rode down in silence, and as we went down the steps to the street, I noticed the man whom we had seen watching the place, lurking down at the lower corner. Kennedy quickened his pace and came up behind him.

"Why, Winters!" exclaimed Craig. "You here?"

"I might say the same to you," grinned the detective not displeased evidently that our trail had crossed his. "I suppose you are looking for Schloss, too. He's up in the Recherche a great deal, playing poker. I understand he owns an interest in the game up there."

Kennedy nodded, but said nothing.

"I just saw one of the cappers for the place go out before you went in."

"Capper?" repeated Kennedy surprised. "Antoinette Moulton a steerer for a gambling joint? What can a rich society woman have to do with a place like that or a man like Schloss?"

Winters smiled sardonically. "Society ladies to-day often get into scrapes of which their husbands know nothing," he remarked. "You didn't know before that Antoinette Moulton, like many of her friends in the smart set, was a gambler—and loser—did you?"

Craig shook his head. He had more of human than scientific interest in a case of a woman of her caliber gone wrong.

"But you must have read of the famous Moulton diamonds?"

"Yes," said Craig, blankly, as if it were all news to him.

"Schloss has them—or at least had them. The jewels she wore at the opera this winter were paste, I understand."

"Does Moulton play?" he asked.

"I think so—but not here, naturally. In a way, I suppose, it is his fault. They all do it. The example of one drives on another."

Instantly there flashed over my mind a host of possibilities. Perhaps, after all, Winters had been right. Schloss had taken this way to make sure of the jewels so that she could not redeem them. Suddenly another explanation crowded that out. Had Mrs. Moulton robbed the safe herself, or hired some one else to do it for her, and had that person gone back on her?

Then a horrid possibility occurred to me. Whatever Antoinette Moulton may have been and done, some one must have her in his power. What a situation for the woman! My sympathy went out to her in her supreme struggle. Even if it had been a real robbery, Schloss might easily recover from it. But for her every event spelled ruin and seemed only to be bringing that ruin closer.

We left Winters, still watching on the trail of Schloss, and went on uptown to the laboratory.



CHAPTER XVIII

THE BURGLAR'S MICROPHONE

That night I was sitting, brooding over the case, while Craig was studying a photograph which he made of the smudge on the glass door down at Schloss'. He paused in his scrutiny of the print to answer the telephone.

"Something has happened to Schloss," he exclaimed seizing his hat and coat. "Winters has been watching him. He didn't go to the Recherche. Winters wants me to meet him at a place several blocks below it Come on. He wouldn't say over the wire what it was. Hurry."

We met Winters in less than ten minutes at the address he had given, a bachelor apartment in the neighborhood of the Recherche.

"Schloss kept rooms here," explained Winters, hurrying us quickly upstairs. "I wanted you to see before anyone else."

As we entered the large and luxuriously furnished living room of the jeweler's suite, a gruesome sight greeted us.

There lay Schloss on the floor, face down, in a horribly contorted position. In one hand, clenched under him partly, the torn sleeve of a woman's dress was grasped convulsively. The room bore unmistakable traces of a violent struggle, but except for the hideous object on the floor was vacant.

Kennedy bent down over him. Schloss was dead. In a corner, by the door, stood a pile of grips, stacked up, packed, and undisturbed.

Winters who had been studying the room while we got our bearings picked up a queer-looking revolver from the floor. As he held it up I could see that along the top of the barrel was a long cylinder with a ratchet or catch at the butt end. He turned it over and over carefully.

"By George," he muttered, "it has been fired off."

Kennedy glanced more minutely at the body. There was not a mark on it. I stared about vacantly at the place where Winters had picked the thing up.

"Look," I cried, my eye catching a little hole in the baseboard of the woodwork near it.

"It must have fallen and exploded on the floor," remarked Kennedy. "Let me see it, Winters."

Craig held it at arm's length and pulled the catch. Instead of an explosion, there came a cone of light from the top of the gun. As Kennedy moved it over the wall, I saw in the center of the circle of light a dark spot.

"A new invention," Craig explained. "All you need to do is to move it so that little dark spot falls directly on an object. Pull the trigger— the bullet strikes the dark spot. Even a nervous and unskilled marksman becomes a good shot in the dark. He can even shoot from behind the protection of something—and hit accurately."

It was too much for me. I could only stand and watch Kennedy as he deftly bent over Schloss again and placed a piece of chemically prepared paper flat on the forehead of the dead man.

When he withdrew it, I could see that it bore marks of the lines on his head. Without a word, Kennedy drew from his pocket a print of the photograph of the smudge on Schloss' door.

"It is possible," he said, half to himself, "to identify a person by means of the arrangement of the sweat glands or pores. Poroscopy, Dr. Edmond Locard, director of the Police Laboratory at Lyons, calls it. The shape, arrangement, number per square centimeter, all vary in different individuals. Besides, here we have added the lines of the forehead."

He was studying the two impressions intensely. When he looked up from his examination, his face wore a peculiar expression.

"This is not the head which was placed so close to the glass of the door of Schloss' office, peering through, on the night of the robbery, in order to see before picking the lock whether the office was empty and everything ready for the hasty attack on the safe."

"That disposes of my theory that Schloss robbed himself," remarked Winters reluctantly. "But the struggle here, the sleeve of the dress, the pistol—could he have been shot?"

"No, I think not," considered Kennedy. "It looks to me more like a case of apoplexy."

"What shall we do?" asked Winters. "Far from clearing anything up, this complicates it."

"Where's Muller?" asked Kennedy. "Does he know? Perhaps he can shed some light on it."

The clang of an ambulance bell outside told that the aid summoned by Winters had arrived.

We left the body in charge of the surgeon and of a policeman who arrived about the same time, and followed Winters.

Muller lived in a cheap boarding house in a shabbily respectable street downtown, and without announcing ourselves we climbed the stairs to his room. He looked up surprised but not disconcerted as we entered.

"What's the matter?" he asked.

"Muller," shot out Winters, "we have just found Mr. Schloss dead!"

"D-dead!" he stammered.

The man seemed speechless with horror.