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."