"Craig, I believe that when you are absorbed in a case, you would rather work than eat. Did you have any lunch after I left you?"

"I don't think so," he replied, regarding the beaker and not his answer. "Now, Walter, old fellow, I don't want you to be offended with me, but really I can work better if you don't constantly remind me of such things as eating and sleeping. Say, do you want to help me—really?"

"Certainly. I am as interested in the case as you are, but I can't make heads or tails of it," I replied.

"Then, I wish you would look up Mrs. Popper to-night and have a private seance with her. What I want you to do particularly is to get a good idea of the looks of the room in which she is accustomed to work. I'm going to duplicate it here in my laboratory as nearly as possible. Then I want you to arrange with her for a private 'circle' here to-morrow night. Tell her it is with a few professors at the university who are interested in psychical research and that Mr. Vandam will be present. I'd rather have her come willingly than to force her to come. Incidentally watch that manager of hers, Farrington. By all means he must accompany her."

That evening I dropped casually in on Mrs. Popper. She was a woman of great brilliance and delicacy, both in her physical and mental perceptions, of exceptional vivacity and cleverness. She must have studied me more closely than I was aware of, for I believe she relied on diverting my attention whenever she desired to produce one of her really wonderful results. Needless to say, I was completely mystified by her performance. She did spirit writing that would have done credit to the immortal Slade, told me a lot of things that were true, and many more that were unverifiable or hopelessly vague. It was really worth much more than the price, and I did not need to feign the interest necessary to get her terms for a circle in the laboratory.

Of course I had to make the terms with Farrington. The first glance aroused my suspicions of him. He was shifty-eyed, and his face had a hard and mercenary look. In spite of, perhaps rather because of, my repugnance we quickly came to an agreement, and as I left the apartment I mentally resolved to keep my eye on him.

Craig came in late, having been engaged in his chemical analyses all the evening. From his manner I inferred that they had been satisfactory, and he seemed much gratified when I told him that I had arranged successfully for the seance and that Farrington would accompany the medium.

As we were talking over the case a messenger arrived with a note from O'Connor. It was written with his usual brevity: "Have just found from servants that Farrington and Mrs. P. have key to Vandam house. Wish I had known it before. House shadowed. No one has entered or left it to-night."

Craig looked at his watch. It was a quarter after one. "The ghost won't walk to-night, Walter," he said as he entered his bedroom for a much-needed rest. "I guess I was right after all in getting the capsules as soon as possible. The ghost must have flitted unobserved in there this morning directly after the maid brought them back from the druggist."

Again, the next morning, he had me out of bed bright and early. As we descended from the Sixth Avenue "L," he led me into a peculiar little shop in the shadow of the "L" structure. He entered as though he knew the place well; but, then, that air of assurance was Kennedy's stock in trade and sat very well on him.

Few people, I suppose, have ever had a glimpse of this workshop of magic and deception. This little shop of Marina's was the headquarters of the magicians of the country. Levitation and ghostly disappearing hands were on every side. The shelves in the back of the shop were full of nickel, brass, wire, wood, and papier-mache contrivances, new and strange to the eye of the uninitiated. Yet it was all as systematic as a hardware shop.

"Is Signor Marina in?" asked Craig of a girl in the first room, given up to picture post-cards. The room was as deceptive as the trade, for it was only an anteroom to the storeroom I have described above. This storeroom was also a factory, and half a dozen artisans were hard at work in it.

Yes, the signor was in, the girl replied, leading us back into the workshop. He proved to be a short man with a bland, open face and frank eyes, the very antithesis of his trade.

"I have arranged for a circle with Mrs. May Popper," began Kennedy, handing the man his card. "I suppose you know her?"

"Indeed yes," he answered. "I furnished her seance room."

"Well, I want to hire for to-night just the same sort of tables, cabinets, carpets, everything that she has—only hire, you understand, but I am willing to pay you well for them. It is the best way to get a good sitting, I believe. Can you do it?"

The little man thought a moment, then replied: "Si, signor yes—very nearly, near enough. I would do anything for Mrs. Popper. She is a good customer. But her manager—"

"My friend here, Mr. Jameson, has had seances with her in her own apartment," interposed Craig. "Perhaps he can help you to recollect just what is necessary."

"I know very well, signor. I have the duplicate bill, the bill which was paid by that Farrington with a check from the banker Vandam. Leave it to me."

"Then you will get the stuff together this morning and have it up to my place this afternoon."

"Yes, Professor, yes. It is a bargain. I would do anything for Mrs. Popper—she is a fine woman."

Late that afternoon I rejoined Craig at his laboratory. Signor Marina had already arrived with a truck and was disposing the paraphernalia about the laboratory. He had first laid a thick black rug. Mrs. Popper very much affected black carpets, and I had noticed that Vandam's room was carpeted in black, too. I suppose black conceals everything that one oughtn't to see at a seance.

A cabinet with a black curtain, several chairs, a light deal table, several banjos, horns, and other instruments were disposed about the room. With a few suggestions from me we made a fair duplication of the hangings on the walls. Kennedy was manifestly anxious to finish, and at last it was done.

After Marina had gone, Kennedy stretched a curtain over the end of the room farthest from the cabinet. Behind it he placed on a shelf the apparatus composed of the pendulums and magnets. The beakers and test-tubes were also on this shelf.

He had also arranged that the cabinet should be so situated that it was next a hallway that ran past his laboratory.

"To-night, Jameson," he said, indicating a spot on the hall wall just back of the cabinet, "I shall want you to bring my guests out here and do a little spirit rapping—I'll tell you just what to do when the time comes."

That night, when we gathered in the transformed laboratory, there were Henry Vandam, Dr. Hanson, Inspector O'Connor, Kennedy, and myself. At last the sound of wheels was heard, and Mrs. Popper drove up in a hansom, accompanied by Farrington. They both inspected the room narrowly and seemed satisfied. I had, as I have said, taken a serious dislike to the man, and watched him closely. I did not like his air of calm assurance.

The lights were switched off, all except one sixteen-candle-power lamp in the farthest corner, shaded by a deep-red globe. It was just light enough to see to read very, large print with difficulty.

Mrs. Popper began immediately with the table. Kennedy and I sat on her right and left respectively, in the circle, and held her hands and feet. I confess to a real thrill when I felt the light table rise first on two legs, then on one, and finally remain suspended in the air, whence it dropped with a thud, as if someone had suddenly withdrawn his support.

The medium sat with her back to the curtain of the cabinet, and several times I could have sworn that a hand reached out and passed close to my head. At least it seemed so. The curtain bulged at times, and a breeze seemed to sweep out from the cabinet.

After some time of this sort of work Craig led gradually up to a request for a materialisation of the control of Vandam, but Mrs. Popper refused. She said she did not feel strong enough, and Farrington put in a hasty word that he, too, could feel that "there was something working against them." But Kennedy was importunate and at last she consented to see if "John" would do some rapping, even if he could not materialise.

Kennedy asked to be permitted to put the questions.

"Are you the 'John' who appears to Mr. Vandam every night at twelve-thirty?"

Rap! rap! rap! came the faint reply from the cabinet. Or rather it seemed to me to come from the floor near the cabinet, and perhaps to be a trifle muffled by the black carpet.

"Are you in communication with Mrs. Vandam?"

Rap! rap! rap!

"Can she be made to rap for us?"

Rap! rap!

"Will you ask her a question and spell out her answer?"

Rap! rap! rap!

Craig paused a moment to frame the question, then shot it out point-blank: "Does Mrs. Vandam know now in the other world whether anyone in this room substituted a morphine capsule for one of those ordered by her three days before she died? Does she know whether the same person has done the same thing with those later ordered by Mr. Vandam?"

"John" seemed considerably perturbed at the mention of capsules. It was a long time before any answer was forthcoming. Kennedy was about to repeat the question when a faint sound was heard.

Rap!——

Suddenly came a wild scream. It was such a scream as I had never heard before in my life. It came as though a dagger had been thrust into the heart of Mrs. Popper. The lights flashed up as Kennedy turned the switch.

A man was lying flat on the floor—it was Inspector O'Connor. He had succeeded in slipping noiselessly, like a snake, below the curtain into the cabinet. Craig had told him to look out for wires or threads stretched from Mrs. Popper's clothing to the bulging curtain of the cabinet. Imagine his surprise when he saw that she had simply freed her foot from the shoe, which I was carefully holding down, and with a backward movement of the leg was reaching out into the cabinet behind her chair and was doing the rapping with her toes.

Lying on the floor he had grasped her foot and caught her heel with a firm hand. She had responded with a wild yell that showed she knew she was trapped. Her secret was out.

Hysterically Mrs. Popper began to upbraid the inspector as he rose to his feet, but Farrington quickly interposed.

"Something was working against us to-night, gentlemen. Yet you demanded results. And when the spirits will not come, what is she to do? She forgets herself in her trance; she produces, herself, the things that you all could see supernaturally if you were in sympathy."

The mere sound of Farrington's voice seemed to rouse in me all the animosity of my nature. I felt that a man who could trump up an excuse like that when a person was caught with the goods was capable of almost anything.

"Enough of this fake seance," exclaimed Craig. "I have let it go on merely for the purpose of opening the eyes of a certain deluded gentleman in this room. Now, if you will all be seated I shall have something to say that will finally establish whether Mary Vandam was the victim of accident, suicide, or murder."

With hearts beating rapidly we sat in silence.

Craig took the beakers and test-tubes from the shelf behind the curtain and placed them on the little deal table that had been so merrily dancing about the room.

"The increasing frequency with which tales of murder by poison appear in the newspapers," he began formally, "is proof of how rapidly this new civilisation of ours is taking on the aspects of the older civilisations across the seas. Human life is cheap in this country; but the ways in which human life has been taken among us have usually been direct, simple, aboveboard, in keeping with our democratic and pioneer traditions. The pistol and the bowie-knife for the individual, the rope and the torch for the mob, have been the usual instruments of sudden death. But when we begin to use poisons most artfully compounded in order to hasten an expected bequest and remove obstacles in its way—well, we are practising an art that calls up all the memories of sixteenth century Italy.

"In this beaker," he continued, "I have some of the contents of the stomach of the unfortunate woman. The coroner's physician has found that they show traces of morphine. Was the morphine in such quantities as to be fatal? Without doubt. But equally without doubt analysis could not discover and prove it in the face of one inconsistency. The usual test which shows morphine poisoning failed in this case. The pupils of her eyes were not symmetrically contracted. In fact they were normal.

"Now, the murderer must have known of this test. This clever criminal also knew that to be successful in the use of this drug where others had failed, the drug must be skilfully mixed with something else. In that first box of capsules there were six. The druggist compounded them correctly according to the prescription. But between the time when they came into the house from the druggist's and the time when she took the first capsule, that night, someone who had access to the house emptied one capsule of its harmless contents and refilled it with a deadly dose of morphine—a white powder which looks just like the powder already in the capsules.

"Why, then, the normal pupils of the eyes? Simply because the criminal put a little atropine, or belladonna, with the morphine. My tests show absolutely the presence of atropine, Dr. Hanson," said Craig, bowing to the physician.

"The best evidence, however, is yet to come. A second box of six capsules, all intact, was discovered yesterday in the possession of Henry Vandam. I have analysed the capsules. One contains no quinine at all—it is all morphine and atropine. It is, without doubt, precisely similar to the capsule which killed Mrs. Vandam. Another night or so, and Henry Vandam would have died the same death."

The old man groaned. Two such exposures had shaken him. He looked from one of us to another as if not knowing in whom he could trust. But Kennedy hurried on to his next point.

"Who was it that gave the prescription to Mrs. Vandam originally? She is dead and cannot tell. The others won't tell, for the person who gave her that prescription was the person who later substituted the fatal capsule in place of the harmless. The original prescription is here. I have been able to discover from it nothing at all by examining the handwriting. Nor does the texture of the paper indicate anything to me. But the ink—ah, the ink.

"Most inks seem very similar, I suppose, but to a person who has made a study of the chemical composition of ink they are very different. Ink is composed of iron tannate, which on exposure to air gives the black of writing. The original pigment—say blue or blue-black ink—is placed in the ink, to make the writing visible at first, and gradually fades, giving place to the black of the tannate which is formed. The dyestuffs employed in the commercial inks of to-day vary in colour from pale greenish blue to indigo and deep violet. No two give identical reactions—at all events not when mixed with the iron tannate to form the pigment in writing.

"It is owing to the difference in these provisional colouring matters that it is possible to distinguish between writing written with different kinds of ink. I was able easily to obtain samples of the inks used by the Vandams, by Mrs. Popper, by Mr. Farrington, and by the druggist. I have compared the writing of the original prescription with a colour scale of my own construction, and I have made chemical tests. The druggist's ink conforms exactly to the writing on the two pill-boxes, but not to the prescription. One of the other three inks conforms by test absolutely to the ink in that prescription signed 'Dr. C. W. H.' as a blind. In a moment my chain of evidence against the owner of that bottle of ink will be complete."

I could not help but think of the two pendulums on the shelf behind the curtain, but Craig said nothing for a moment to indicate that he referred to that apparatus. We sat dazed. Farrington seemed nervous and ill at ease. Mrs. Popper, who had not recovered from the hysterical condition of her exposure, with difficulty controlled her emotion. Vandam was crushed.

"I have not only arranged this laboratory so as to reproduce Mrs. Popper's seance-room," began Craig afresh, "but I have had the cabinet placed in relatively the same position a similar cabinet occupies in Mr. Vandam's private seance-room in the Vandam mansion.

"One night, Mr. Jameson and myself were visiting Mr. Vandam. At precisely twelve-thirty we heard most unaccountable rappings from that cabinet. I particularly noted the position of the cabinet. Back of it ran a hallway. That is duplicated here. Back of this cabinet is a hallway. I had heard of these rappings before we went, but was afraid that it would be impossible for me to catch the ghost red handed. There is a limit to what you can do the first time you enter a man's house, and, besides, that was no time to arouse suspicion in the mind of anyone. But science has a way out of every dilemma. I determined to learn something of these rappings."

Craig paused and glanced first at Farrington, then at Mrs. Popper, and then at Mr. Vandam.

"Mr. Jameson," he resumed, "will escort the doctor, the inspector, Mr. Farrington, Mrs. Popper, and Mr. Vandam into my imitation hall of the Vandam mansion. I want each of you in turn to tiptoe up that hall to a spot indicated on the wall, back of the cabinet, and strike that spot several sharp blows with your knuckles."

I did as Craig instructed tiptoeing up myself first so that they could not mistake his meaning. The rest followed separately, and after a moment we returned silently in suppressed excitement to the room.

Craig was still standing by the table, but now the pendulums with the magnets and needles and the drums worked by clockwork were before him.

"Another person outside the Vandam family had a key to the Vandam mansion," he began gravely. "That person, by the way, was the one who waited, night by night, until Mrs. Vandam took the fatal capsule, and then when she had taken it apprised the old man of the fact and strengthened an already blind faith in the shadow world."

You could have heard a pin drop. In fact you could almost have felt it drop.

"That other person who, unobserved, had free access to the house," he continued in the breathless stillness, "is in this room now."

He was looking at O'Connor as if for corroboration. O'Connor nodded. "Information derived from the butler," he muttered.

"I did not know this until yesterday," Kennedy continued, "but I suspected that something of the sort existed when I was first told by Dr. Hanson of the rappings. I determined to hear those rappings, and make a record of them. So, the night Mr. Jameson and I visited Mr. Vandam, I carried this little instrument with me."

Almost lovingly he touched the pendulums on the table. They were now at rest and kept so by means of a lever that prevented all vibration whatever.

"See, I release this lever—now, let no one in the room move. Watch the needles on the paper as the clockwork revolves the drums. I take a step—ever so lightly. The pendulums vibrate, and the needles trace a broken line on the paper on each drum. I stop; the lines are practically straight. I take another step and another, ever so lightly. See the delicate pendulums vibrate? See, the lines they trace are jagged lines."

He stripped the paper off the drums and laid it flat on the table before him, with two other similar pieces of paper.

"Just before the time of the rapping I placed this instrument in the corner of the Vandam cabinet, just as I placed it in this cabinet after Mr. Jameson conducted you from the room. In neither case were suspicions aroused. Everything in both cases was perfectly normal—I mean the 'ghost' was in ignorance of the presence, if not the very existence, of this instrument.

"This is an improved seismograph," he explained, "one after a very recent model by Prince Galitzin of the Imperial Academy of St. Petersburg. The seismograph, as you know, was devised to register earthquakes at a distance. This one not only measures the size of a distant earthquake, but the actual direction from which the earth-tremors come. That is why there are two pendulums and two drums.

"The magnetic arrangement is to cut short the vibrations set up in the pendulums, to prevent them from continuing to vibrate after the first shock. Thus they are ready in an instant to record another tremor. Other seismographs continue to vibrate for a long time as a result of one tremor only. Besides, they give little indication of the direction from which the tremors come.

"I think you must all appreciate that your tiptoeing up the hall must cause a far greater disturbance in this delicate seismograph than even a very severe earthquake thousands of miles away, which it was built to record."

He paused and examined the papers sharply.

"This is the record made by the 'ghost's' walk the other night," he said, holding up two of them in his left hand. "Here on the table, on two other longer sheets, I have records of the vibrations set up by those in this room walking to-night.

"Here is Mr. Jameson's—his is not a bit like the ghost's. Nor is Mr. Vandam's. Least of all are Dr. Hanson's and Inspector O'Connor's, for they are heavy men.

"Now here is Mr. Farrington's"—he bent down closely, "he is a light man, and the ghost was light."

Craig was playing with his victim like a cat with a mouse.

Suddenly I felt something brush by me, and with a swish of air and of garments I saw Mrs. Popper fling herself wildly at the table that bore the incriminating records. In another instant Farrington was on his feet and had made a wild leap in the same direction.

It was done so quickly that I must have acted first and thought afterward. I found myself in the midst of a melee with my hand at his throat and his at mine. O'Connor with a jiu-jitsu movement bent Farrington's other arm until he released me with a cry of pain.

In front of me I saw Craig grasping Mrs. Popper's wrists as in a vise. She was glaring at him like a tigress.

"Do you suppose for a moment that that toy is going to convince the world that Henry Vandam has been deceived and that the spirit which visited him was a fraud? Is that why you have lured me here under false pretences, to play on my feelings, to insult me, to take advantage of a lone, defenceless woman, surrounded by hostile men? Shame on you," she added contemptuously. "You call yourself a gentleman, but I call you a coward."

Kennedy, always calm and collected, ignored the tirade. His voice was as cold as steel as he said: "It would do little good, Mrs. Popper, to destroy this one link in the chain I have forged. The other links are too heavy for you. Don't forget the evidence of the ink. It was your ink. Don't forget that Henry Vandam will not any longer conceal that he has altered his will in favour of you. To-night he goes from here to his lawyer's to draw up a new will altogether. Don't forget that you have caused the Vandams separately to have the prescription filled, and that you are now caught in the act of a double murder. Don't forget that you had access to the Vandam mansion, that you substituted the deadly for the harmless capsules. Don't forget that your rappings announced the death of one of your victims and urged the other, a cruelly wronged and credulous old man, to leave millions to you who had deceived and would have killed him.

"No, the record of the ghost on the seismograph was not Mr. Farrington's, as I implied at the moment when you so kindly furnished this additional proof of your guilt by trying to destroy the evidence. The ghost was you, Mrs. Popper, and you are at liberty to examine the markings as minutely as you please, but you must not destroy them. You are an astute criminal, Mrs. Popper, but to-night you are under arrest for the murder of Mary Vandam and the attempted murder of Henry Vandam."



VI. The Diamond Maker

"I've called, Professor Kennedy, to see if we can retain you in a case which I am sure will tax even your resources. Heaven knows it has taxed ours."

The visitor was a large, well-built man. He placed his hat on the table and, without taking off his gloves, sat down in an easy chair which he completely filled.

"Andrews is my name—third vice-president of the Great Eastern Life Insurance Company. I am the nominal head of the company's private detective force, and though I have some pretty clever fellows on my staff we've got a case that, so far, none of us has been able to unravel. I'd like to consult you about it."

Kennedy expressed his entire willingness to be consulted, and after the usual formalities were over, Mr. Andrews proceeded.

"I suppose you are aware that the large insurance companies maintain quite elaborate detective forces and follow very keenly such of the cases of their policy-holders as look at all suspicious. This case which I wish to put in your hands is that of Mr. Solomon Morowitch, a wealthy Maiden Lane jeweller. I suppose you have read something in the papers about his sudden death and the strange robbery of his safe?"

"Very little," replied Craig. "There hasn't been much to read."

"Of course not, of course not," said Mr. Andrews with some show of gratification. "I flatter myself that we have pulled the wires so as to keep the thing out of the papers as much as possible. We don't want to frighten the quarry till the net is spread. The point is, though, to find out who is the quarry. It's most baffling."

"I am at your service," interposed Craig quietly, "but you will have to enlighten me as to the facts in the case. As to that, I know no more than the newspapers."

"Oh, certainly, certainly. That is to say, you know nothing at all and can approach it without bias." He paused and then, seeming to notice something in Craig's manner, added hastily: "I'll be perfectly frank with you. The policy in question is for one hundred thousand dollars, and is incontestable. His wife is the beneficiary. The company is perfectly willing to pay, but we want to be sure that it is all straight first. There are certain suspicious circumstances that in justice to ourselves we think should be cleared up. That is all—believe me. We are not seeking to avoid an honest liability."

"What are these suspicious circumstances?" asked Craig, apparently satisfied with the explanation.

"This is in strict confidence, gentlemen," began Mr. Andrews. "Mr. Morowitch, according to the story as it comes to us, returned home late one night last week, apparently from his office, in a very weakened, a semiconscious, condition. His family physician, Doctor Thornton, was summoned, not at once, but shortly. He pronounced Mr. Morowitch to be suffering from a congestion of the lungs that was very like a sudden attack of pneumonia.

"Mr. Morowitch had at once gone to bed, or at least was in bed, when the doctor arrived, but his condition grew worse so rapidly that the doctor hastily resorted to oxygen, under which treatment he seemed to revive. The doctor had just stepped out to see another patient when a hurry call was sent to him that Mr. Morowitch was rapidly sinking. He died before the doctor could return. No statement whatever concerning the cause of his sudden illness was made by Mr. Morowitch, and the death-certificate, a copy of which I have, gives pneumonia as the cause of death. One of our men has seen Doctor Thornton, but has been able to get nothing out of him. Mrs. Morowitch was the only person with her, husband at the time."

There was something in his tone that made me take particular note of this last fact, especially as he paused for an instant.

"Now, perhaps there would be nothing surprising about it all, so far at least, were it not for the fact that the following morning, when his junior partner, Mr. Kahan, opened the place of business, or rather went to it, for it was to remain closed, of course, he found that during the night someone had visited it. The lock on the great safe, which contained thousands of dollars' worth of diamonds, was intact; but in the top of the safe a huge hole was found—an irregular, round hole, big enough to put your foot through. Imagine it, Professor Kennedy, a great hole in a safe that is made of chrome steel, a safe that, short of a safety-deposit vault, ought to be about the strongest thing on earth.

"Why, that steel would dull and splinter even the finest diamond-drill before it made an impression. The mere taking out and refitting of drills into the brace would be a most lengthy process. Eighteen or twenty hours is the time by actual test which it would take to bore such a hole through those laminated plates, even if there were means of exerting artificial pressure. As for the police, they haven't even a theory yet."

"And the diamonds"

"All gone—everything of any value was gone. Even the letter-files were ransacked. His desk was broken open, and papers of some nature had been taken out of it. Thorough is no name for the job. Isn't that enough to arouse suspicion?"

"I should like to see that safe," was all Kennedy said.

"So you shall, so you shall," said Mr. Andrews. "Then we may retain you in our service? My car is waiting down-stairs. We can go right down to Maiden Lane if you wish."

"You may retain me on one condition," said Craig without moving. "I am to be free to get at the truth whether it benefits or hurts the company, and the case is to be entirely in my hands."

"Hats on," agreed Mr. Andrews, reaching in his vest pocket and pulling out three or four brevas. "My chauffeur is quite a driver. He can almost beat the subway down."

"First, to my laboratory," interposed Craig. "It will take only a few minutes."

We drove up to the university and stopped on the campus while Craig hurried into the Chemistry Building to get something.

"I like your professor of criminal science;" said Andrews to me, blowing a huge fragrant cloud of smoke.

I, for my part, liked the vice-president. He was a man who seemed thoroughly to enjoy life, to have most of the good things, and a capacity for getting out of them all that was humanly possible. He seemed to be particularly enjoying this Morowitch case.

"He has solved some knotty cases," was all I said. "I've come to believe there is no limit to his resourcefulness."

"I hope not. He's up against a tough one this trip, though, my boy."

I did not even resent the "my boy." Andrews was one of those men in whom we newspaper writers instinctively believe. I knew that it would be "pens lifted" only so long as the case was incomplete. When the time comes with such men they are ready to furnish us the best "copy" in the world.

Kennedy quickly rejoined us, carrying a couple of little glass bottles with ground-glass stoppers.

Morowitch & Co. was, of course, closed when we arrived, but we had no trouble in being admitted by the Central Office man who had been detailed to lock the barn door after the horse was stolen. It was precisely as Mr. Andrews had said. Mr. Kahan showed us the safe. Through the top a great hole had been made—I say made, for at the moment I was at a loss to know whether it had been cut, drilled, burned, blown out, or what-not.

Kennedy examined the edges of the hole carefully, and just the trace of a smile of satisfaction flitted over his face as he did so. Without saying a word he took the glass stopper out of the larger bottle which he had brought and poured the contents on the top of the safe near the hole. There it lay, a little mound of reddish powder.

Kennedy took a little powder of another kind from the other bottle and lighted it with a match.

"Stand back—close to the wall," he called as he dropped the burning mass on the red powder. In two or three leaps he joined us at the far end of the room.

Almost instantly a dazzling, intense flame broke out, and sizzled and crackled. With bated breath we watched. It was almost incredible, but that glowing mass of powder seemed literally to be sinking, sinking right down into the cold steel. In tense silence we waited. On the ceiling we could still see the reflection of the molten mass in the cup which it had burned for itself in the top of the safe.

At last it fell through into the safe—fell as the burning roof of a frame building would fall into the building. No one spoke a word, but as we cautiously peered over the top of the safe we instinctively turned to Kennedy for an explanation. The Central Office man, with eyes as big as half-dollars, acted almost as if he would have liked to clap the irons on Kennedy. For there in the top of the safe was another hole, smaller but identical in nature with the first one.

"Thermit," was all Kennedy said.

"Thermit?" echoed Andrews, shifting the cigar which he had allowed to go out in the excitement.

"Yes, an invention of a chemist named Goldschmidt, of Essen, Germany. It is a compound of iron oxide, such as comes off a blacksmith's anvil or the rolls of a rolling-mill, and powdered metallic aluminum. You could thrust a red-hot bar into it without setting it off, but when you light a little magnesium powder and drop it on thermit, a combustion is started that quickly reaches fifty-four hundred degrees Fahrenheit. It has the peculiar property of concentrating its heat to the immediate spot on which it is placed. It is one of the most powerful oxidising agents known, and it doesn't even melt the rest of the steel surface. You see how it ate its way through the steel. Either black or red thermit will do the trick equally well."

No one said anything. There was nothing to say.

"Someone uncommonly clever, or instructed by someone uncommonly clever, must have done that job," added Craig. "Well, there is nothing more to be done here," he added, after a cursory look about the office. "Mr. Andrews, may I have a word with you? Come on, Jameson. Good day, Mr. Kahan. Good day, Officer."

Outside we stopped for a moment at the door of Andrews's car.

"I shall want to see Mr. Morowitch's papers at home," said Craig, "and also to call on Doctor Thornton. Do you think I shall have any difficulty?"

"Not at all," replied Mr. Andrews, "not at all. I will go with you myself and see that you have none. Say, Professor Kennedy," he broke out, "that was marvellous. I never dreamed such a thing was possible. But don't you think you could have learned something more up there in the office by looking around?"

"I did learn it," answered Kennedy. "The lock on the door was intact—whoever did the job let himself in by a key. There is no other way to get in."

Andrews gave a low whistle and glanced involuntarily up at the window with the sign of Morowitch & Co. in gold letters several floors above.

"Don't look up. I think that was Kahan looking out at us," he said, fixing his eyes on his cigar. "I wonder if he knows more about this than he has told! He was the 'company,' you know, but his interest in the business was only very slight. By George—"

"Not too fast, Mr. Andrews," interrupted Craig. "We have still to see Mrs. Morowitch and the doctor before we form any theories."

"A very handsome woman, too," said Andrews, as we seated ourselves in the car: "A good deal younger than Morowitch. Say, Kahan isn't a bad-looking chap, either, is he? I hear he was a very frequent visitor at his partner's house. Well, which first, Mrs. M. or the doctor?"

"The house," answered Craig.

Mr. Andrews introduced us to Mrs. Morowitch, who was in very deep mourning, which served, as I could not help noticing, rather to heighten than lessen her beauty. By contrast it brought out the rich deep colour of her face and the graceful lines of her figure. She was altogether a very attractive young widow.

She seemed to have a sort of fear of Andrews, whether merely because he represented the insurance company on which so much depended or because there were other reasons for fear, I could not, of course, make out. Andrews was very courteous and polite, yet I caught myself asking if it was not a professional rather than a personal politeness. Remembering his stress on the fact that she was alone with her husband when he died, it suddenly flashed across my mind that somewhere I had read of a detective who, as his net was being woven about a victim, always grew more and more ominously polite toward the victim. I know that Andrews suspected her of a close connection with the case. As for myself, I don't know what I suspected as yet.

No objection was offered to our request to examine Mr. Morowitch's personal effects in the library, and accordingly Craig ransacked the desk and the letter-file. There was practically nothing to be discovered.

"Had Mr. Morowitch ever received any threats of robbery?" asked Craig, as he stood before the desk.

"Not that I know of," replied Mrs. Morowitch. "Of course every jeweller who carries a large stock of diamonds must be careful. But I don't think my husband had any special reason to fear robbery. At least he never said anything about it. Why do you ask?"

"Oh, nothing. I merely thought there might be some hint as to the motives of the robbery," said Craig. He was fingering one of those desk-calendars which have separate leaves for each day with blank spaces for appointments.

"'Close deal Poissan,'" he read slowly from one of the entries, as if to himself. "That's strange. It was the correspondence under the letter 'P' that was destroyed at the office, and there is nothing in the letter-file here, either. Who was Poissan?"

Mrs. Morowitch hesitated, either from ignorance or from a desire to evade the question. "A chemist, I think," she said doubtfully. "My husband had some dealings with him—some discovery he was going to buy. I don't know anything about it. I thought the deal was off."

"The deal?"

"Really, Mr. Kennedy, you had better ask Mr. Kahan. My husband talked very, little to me about business affairs."

"But what was the discovery?"

"I don't know. I only heard Mr. Morowitch and Mr. Kahan refer to some deal about a discovery regarding diamonds."

"Then Mr. Kahan knows about it?"

"I presume so."

"Thank you, Mrs. Morowitch," said Kennedy, when it was evident that she either could not or would not add anything to what she had said. "Pardon us for causing all this trouble."

"No trouble at all," she replied graciously, though I could see she was intent on every word and motion of Kennedy and Andrews.

Kennedy stopped the car at a drug-store a few blocks away and asked for the business telephone directory. In an instant, under chemists, he put his finger on the name of Poissan—"Henri Poissan, electric furnaces,—William St.," he read.

"I shall visit him to-morrow morning. Now for the doctor."

Doctor Thornton was an excellent specimen of the genus physician to the wealthy—polished, cool, suave. One of Mr. Andrews's men, as I have said, had seen him already, but the interview had been very unsatisfactory. Evidently, however, the doctor had been turning something over in his mind since then and had thought better of it. At any rate, his manner was cordial enough now.

As he closed the doors to his office, he began to pace the floor. "Mr. Andrews," he said, "I am in some doubt whether I had better tell you or the coroner what I know. There are certain professional secrets that a doctor must, as a duty to his patients, conceal. That is professional ethics. But there are also cases when, as a matter of public policy, a doctor should speak out."

He stopped and faced us.

"I don't mind telling you that I dislike the publicity that would attend any statement I might make to the coroner."

"Exactly," said Andrews. "I appreciate your position exactly. Your other patients would not care to see you involved in a scandal—or at least you would not care to have them see you so involved, with all the newspaper notoriety such a thing brings."

Doctor Thornton shot a quick glance at Andrews, as if he would like to know just how much his visitor knew or suspected.

Andrews drew a paper from his pocket. "This is a copy of the death-certificate," he said. "The Board of Health has furnished it to us. Our physicians at the insurance company tell me it is rather extraordinarily vague. A word from us calling the attention of the proper authorities to it would be sufficient, I think. But, Doctor, that is just the point. We do not desire publicity any more than you do. We could have the body of Mr. Morowitch exhumed and examined, but I prefer to get the facts in the case without resorting to such extreme measures."

"It would do no good," interrupted the doctor hastily. "And if you'll save me the publicity, I'll tell you why."

Andrews nodded, but still held the death-certificate where the doctor was constantly reminded of it.

"In that certificate I have put down the cause of death as congestion of the lungs due to an acute attack of pneumonia. That is substantially correct, as far as it goes. When I was summoned to see Mr. Morowitch I found him in a semiconscious state and scarcely breathing. Mrs. Morowitch told me that he had been brought home in a taxicab by a man who had picked him up on William Street. I'm frank to say that at first sight I thought it was a case of plain intoxication, for Mr. Morowitch sometimes indulged a little freely when he made a splendid deal. I smelled his breath, which was very feeble. It had a sickish sweet odour, but that did not impress me at the time. I applied my stethoscope to his lungs. There was a very marked congestion, and I made as my working diagnosis pneumonia. It was a case for quick and heroic action. In a very few minutes I had a tank of oxygen from the hospital.

"In the meantime I had thought over that sweetish odour, and it flashed on my mind that it might, after all, be a case of poisoning. When the oxygen arrived I administered it at once. As it happens, the Rockefeller Institute has just published a report of experiments with a new antidote for various poisons, which consists simply in a new method of enforced breathing and throwing off the poison by oxidising it in that way. In either case—the pneumonia theory or the poison theory—this line of action was the best that I could have adopted on the spur of the moment. I gave him some strychnine to strengthen his heart and by hard work I had him resting apparently a little easier. A nurse had been sent for, but had not arrived when a messenger came to me telling of a very sudden illness of Mrs. Morey, the wife of the steel-magnate. As the Morey home is only a half-block away, I left Mr. Morowitch, with very particular instructions to his wife as to what to do.

"I had intended to return immediately, but before I got back Mr. Morowitch was dead. Now I think I've told you all. You see, it was nothing but a suspicion—hardly enough to warrant making a fuss about. I made out the death-certificate, as you see. Probably that would have been all there was to it if I hadn't heard of this incomprehensible robbery. That set me thinking again. There, I'm glad I've got it out of my system. I've thought about it a good deal since your man was here to see me."

"What do you suspect was the cause of that sweetish odour?" asked Kennedy.

The doctor hesitated. "Mind, it is only a suspicion. Cyanide of potassium or cyanogen gas; either would give such an odour."

"Your treatment would have been just the same had you been certain?"

"Practically the same, the Rockefeller treatment."

"Could it have been suicide" asked Andrews.

"There was no motive for it, I believe," replied the doctor.

"But was there any such poison in the Morowitch house?"

"I know that they were much interested in photography. Cyanide of potassium is used in certain processes in photography."

"Who was interested in photography, Mr. or Mrs. Morowitch?"

"Both of them."

"Was Mrs. Morowitch?"

"Both of them," repeated the doctor hastily. It was evident how Andrews's questions were tending, and it was also evident that the doctor did not wish to commit himself or even to be misunderstood.

Kennedy had sat silently for some minutes, turning the thing over in his mind. Apparently disregarding Andrews entirely, he now asked, "Doctor, supposing it had been cyanogen gas which caused the congestion of the lungs, and supposing it had not been inhaled in quantities large enough to kill outright, do you nevertheless feel that Mr. Morowitch was in a weak enough condition to die as a result of the congestion produced by the gas after the traces of the cyanogen had been perhaps thrown off?"

"That is precisely the impression which I wished to convey."

"Might I ask whether in his semiconscious state he said anything that might at all serve as a clue?"

"He talked ramblingly, incoherently. As near as I can remember it, he seemed to believe himself to have become a millionaire, a billionaire. He talked of diamonds, diamonds, diamonds. He seemed to be picking them up, running his fingers through them, and once I remember he seemed to want to send for Mr. Kahan and tell him something. 'I can make them, Kahan,' he said, 'the finest, the largest, the whitest—I can make them.'"

Kennedy was all attention as Dr. Thornton added this new evidence.

"You know," concluded the doctor, "that in cyanogen poisoning there might be hallucinations of the wildest kind. But then, too, in the delirium of pneumonia it might be the same."

I could see by the way Kennedy acted that for the first time a ray of light had dawned upon him in tracing out the case. As we rose to go, the doctor shook hands with us. His last words were said with an air of great relief, "Gentlemen, I have eased my conscience considerably."

As we parted for the night Kennedy faced Andrews. "You recall that you promised me one thing when I took up this case?" he asked.

Andrews nodded.

"Then take no steps until I tell you. Shadow Mrs. Morowitch and Mr. Kahan, but do not let them know you suspect them of anything. Let me run down this Poissan clue. In other words, leave the case entirely in my hands in other respects. Let me know any new facts you may unearth, and some time to-morrow I shall call on you, and we will determine what the next step is to be. Good night. I want to thank you for putting me in the way of this case. I think we shall all be surprised at the outcome."

It was late the following afternoon before I saw Kennedy again. He was in his laboratory winding two strands of platinum wire carefully about a piece of porcelain and smearing on it some peculiar black glassy granular substance that came in a sort of pencil, like a stick of sealing-wax. I noticed that he was very particular to keep the two wires exactly the same distance from each other throughout the entire length of the piece of porcelain, but I said nothing to distract his attention, though a thousand questions about the progress of the case were at my tongue's end.

Instead I watched him intently. The black substance formed a sort of bridge connecting and covering the wires. When he had finished he said: "Now you can ask me your questions, while I heat and anneal this little contrivance. I see you are bursting with curiosity."

"Well, did you see Poissan?" I asked.

Kennedy continued to heat the wire-covered porcelain. "I did, and he is going to give me a demonstration of his discovery to-night."

"His discovery!"

"You remember Morowitch's 'hallucination,' as the doctor called it? That was no hallucination; that was a reality. This man Poissan says he has discovered a way to make diamonds artificially out of pure carbon in an electric furnace. Morowitch, I believe, was to buy his secret. His dream of millions was a reality—at least to him."

"And did Kahan and Mrs. Morowitch know it?" I asked quickly.

"I don't know yet," replied Craig, finishing the annealing.

The black glassy substance was now a dull grey.

"What's that stuff you were putting on the wire?" I asked.

"Oh, just a by-product made in the manufacture of sulphuric acid," answered Kennedy airily, adding, as if to change the subject: "I want you to go with me to-night. I told Poissan I was a professor in the university and that I would bring one of our younger trustees, the son of the banker, T. Pierpont Spencer, who might put some capital into his scheme. Now, Jameson, while I'm finishing up my work here, run over to the apartment and get my automatic revolver. I may need it to-night. I have communicated with Andrews, and he will be ready. The demonstration will take place at half-past-eight at Poissan's laboratory. I tried to get him to give it here, but he absolutely refused."

Half an hour later I rejoined Craig at his laboratory, and we rode down to the Great Eastern Life Building.

Andrews was waiting for us in his solidly furnished office. Outside I noted a couple of husky men, who seemed to be waiting for orders from their chief.

From the manner in which the vice-president greeted us it was evident that he was keenly interested in what Kennedy was about to do. "So you think Morowitch's deal was a deal to purchase the secret of diamond-making?" he mused.

"I feel sure of it," replied Craig. "I felt sure of it the moment I looked up Poissan and found that he was a manufacturer of electric furnaces. Don't you remember the famous Lemoine case in London and Paris?"

"Yes, but Lemoine was a fakir of the first water;" said Andrews. "Do you think this man is, too?"

"That's what I'm going to find out to-night before I take another step," said Craig. "Of course there can be no doubt that by proper use the electric furnace will make small, almost microscopic diamonds. It is not unreasonable to suppose that some day someone will be able to make large diamonds synthetically by the same process."

"Maybe this man has done it," agreed Andrews. "Who knows? I'll wager that if he has and that if Morowitch had bought an interest in his process Kahan knew of it. He's a sharp one. And Mrs. Morowitch doesn't let grass grow under her feet, when it comes to seeing the main chance as to money. Now just supposing Mr. Morowitch had bought an interest in a secret like that and supposing Kahan was in love with Mrs. Morowitch and that they—"

"Let us suppose nothing, Mr. Andrews," interrupted Kennedy. "At least not yet. Let me see; it is now ten minutes after eight. Poissan's place is only a few blocks from here. I'd like to get there a few minutes early. Let's start."

As we left the office, Andrews signalled to the two men outside, and they quietly followed a few feet in the rear, but without seeming to be with us.

Poissan's laboratory was at the top of a sort of loft building a dozen stories or so high. It was a peculiar building, with several entrances besides a freight elevator at the rear and fire-escapes that led to adjoining lower roofs.

We stopped around the corner in the shadow, and Kennedy and Andrews talked earnestly. As near as I could make out Kennedy was insisting that it would be best for Andrews and his men not to enter the building at all, but wait down-stairs while he and I went up. At last the arrangement was agreed on.

"Here," said Kennedy, undoing a package he had carried, "is a little electric bell with a couple of fresh dry batteries attached to it, and wires that will reach at least four hundred feet. You and the men wait in the shadow here by this side entrance for five minutes after Jameson and I go up. Then you must engage the night watchman in some way. While he is away you will find two wires dangling down the elevator shaft. Attach them to these wires from the bell and the batteries—these two—you know how to do that. The wires will be hanging in the third shaft—only one elevator is running at night, the first. The moment you hear the bell begin to ring; jump into the elevator and come up to the twelfth floor—we'll need you."

As Kennedy and I rode up in the elevator I could not help thinking what an ideal place a down-town office building is for committing a crime, even at this early hour of the evening. If the streets were deserted, the office-buildings were positively uncanny in their grim, black silence with only here and there a light.

The elevator in the first shaft shot down again to the ground floor, and as it disappeared Kennedy took two spools of wire from his pocket and hastily shoved them through the lattice work the third elevator shaft. They quickly unrolled, and I could hear them strike the top of the empty car below in the basement. That meant that Andrews on the ground floor could reach the wires and attach them to the bell.

Quickly in the darkness Kennedy attached the ends of the wires to the curious little coil I had seen him working on in the laboratory, and we proceeded down the hall to the rooms occupied by Poissan, Kennedy had allowed for the wire to reach from the elevator-shaft up this hall, also, and as he walked he paid it out in such a manner that it fell on the floor close to the wall, where, in the darkness, it would never be noticed or stumbled over.

Around an "L" in the hall I could see a ground-glass window with a light shining through it. Kennedy stopped at the window and quickly placed the little coil on the ledge, close up against the glass, with the wires running from it down the hall. Then we entered.

"On time to the minute, Professor," exclaimed Poissan, snapping his watch. "And this, I presume, is the banker who is interested in my great discovery of making artificial diamonds of any size or colour?" he added, indicating me.

"Yes," answered Craig, "as I told you, a son of Mr. T. Pierpont Spencer."

I shook hands with as much dignity as I could assume, for the role of impersonation was a new one to me.

Kennedy carelessly laid his coat and hat on the inside ledge of the ground-glass window, just opposite the spot where he had placed the little coil on the other side of the glass. I noted that the window was simply a large pane of wire-glass set in the wall for the purpose of admitting light in the daytime from the hall outside.

The whole thing seemed eerie to me—especially as Poissan's assistant was a huge fellow and had an evil look such as I had seen in pictures of the inhabitants of quarters of Paris which one does not frequent except in the company of a safe guide. I was glad Kennedy had brought his revolver, and rather vexed that he had not told me to do likewise. However, I trusted that Craig knew what he was about.

We seated ourselves some distance from a table on which was a huge, plain, oblong contrivance that reminded me of the diagram of a parallelopiped which had caused so much trouble in my solid geometry at college.

"That's the electric furnace, sir," said Craig to me with an assumed deference, becoming a college professor explaining things to the son of a great financier. "You see the electrodes at either end? When the current is turned on and led through them into the furnace you can get the most amazing temperatures in the crucible. The most refractory of chemical compounds can be broken up by that heat. What is the highest temperature you have attained, Professor?"

"Something over three thousand degrees Centigrade," replied Poissan, as he and his assistant busied themselves about the furnace.

We sat watching him in silence.

"Ah, gentlemen, now I am ready," he exclaimed at length, when everything was arranged to his satisfaction. "You see, here is a lump of sugar carbon—pure amorphous carbon: Diamonds, as you know, are composed of pure carbon crystallised under enormous pressure. Now, my theory is that if we can combine an enormous pressure and an enormous heat we can make diamonds artificially. The problem of pressure is the thing, for here in the furnace we have the necessary heat. It occurred to me that when molten cast iron cools it exerts a tremendous pressure. That pressure is what I use."

"You know, Spencer, solid iron floats on molten iron like solid water—ice—floats on liquid water," explained Craig to me.

Poissan nodded. "I take this sugar carbon and place it in this soft iron cup. Then I screw on this cap over the cup, so. Now I place this mass of iron scraps in the crucible of the furnace and start the furnace."

He turned a switch, and long yellowish-blue sheets of flame spurted out from the electrodes on either side. It was weird, gruesome. One could feel the heat of the tremendous electric discharge.

As I looked at the bluish-yellow flames they gradually changed to a beautiful purple, and a sickish sweet odour filled the room. The furnace roared at first, but as the vapors increased it became a better conductor of the electricity, and the roaring ceased.

In almost no time the mass of iron scraps became molten. Suddenly Poissan plunged the cast-iron cup into the seething mass. The cup floated and quickly began to melt. As it did so he waited attentively until the proper moment. Then with a deft motion he seized the whole thing with a long pair of tongs and plunged it into a vat of running water. A huge cloud of steam filled the room.

I felt a drowsy sensation stealing over me as the sickish sweet smell from the furnace increased. Gripping the chair, I roused myself and watched Poissan attentively. He was working rapidly. As the molten mass cooled and solidified he took it out of the water and laid it on an anvil.

Then his assistant began to hammer it with careful, sharp blows, chipping off the outside.

"You see, we have to get down to the core of carbon gently," he said, as he picked up the little pieces of iron and threw them into a scrap-box. "First rather brittle cast iron, then hard iron, then iron and carbon, then some black diamonds, and in the very centre the diamonds.

"Ah! we are getting to them. Here is a small diamond. See, Mr. Spencer—gently Francois—we shall come to the large ones presently."

"One moment, Professor Poissan," interrupted Craig; "let your assistant break them out while I stand over him."

"Impossible. You would not know when you saw them. They are just rough stones."

"Oh, yes, I would."

"No, stay where you are. Unless I attend to it the diamonds might be ruined."

There was something peculiar about his insistence, but after he picked out the next diamond I was hardly prepared for Kennedy's next remark.

"Let me see the palms of your hands."

Poissan shot an angry glance at Kennedy, but he did not open his hands.

"I merely wish to convince you, 'Mr. Spencer,'" said Kennedy to me, "that it is no sleight-of-hand trick and that the professor has not several uncut stones palmed in his hand like a prestidigitator."

The Frenchman faced us, his face livid with rage. "You call me a prestidigitator, a fraud—you shall suffer for that! Sacrebleu! Ventre du Saint Gris! No man ever insults the honour of Poissan. Francois, water on the electrodes!"

The assistant dashed a few drops of water on the electrodes. The sickish odour increased tremendously. I felt myself almost going, but with an effort I again roused myself. I wondered how Craig stood the fumes, for I suffered an intense headache and nausea.

"Stop!" Craig thundered. "There's enough cyanogen in this room already. I know your game—the water forms acetylene with the carbon, and that uniting with the nitrogen of the air under the terrific heat of the electric arc forms hydrocyanic acid. Would you poison us, too? Do you think you can put me unconscious out on the street and have a society doctor diagnose my case as pneumonia? Or do you think we shall die quietly in some hospital as a certain New York banker did last year after he had watched an alchemist make silver out of apparently nothing!"

The effect on Poissan was terrible. He advanced toward Kennedy, the veins in his face fairly standing out. Shaking his forefinger, he shouted: "You know that, do you? You are no professor, and this is no banker. You are spies, spies. You come from the friends of Morowitch, do you? You have gone too far with me."

Kennedy said nothing, but retreated and took his coat and hat off the window ledge. The hideous penetrating light of the tongues of flame from the furnace played on the ground-glass window.

Poissan laughed a hollow laugh.

"Put down your hat and coat, Mistair Kennedy," he hissed. "The door has been locked ever since you have been here. Those windows are barred, the telephone wire is cut, and it is three hundred feet to the street. We shall leave you here when the fumes have overcome you. Francois and I can stand them up to a point, and when we reach that point we are going."

Instead of being cowed Kennedy grew bolder, though I, for my part, felt so weakened that I feared the outcome of a hand-to-hand encounter with either Poissan or Francois, who appeared as fresh as if nothing had happened. They were hurriedly preparing to leave us.

"That would do you no good," Kennedy rejoined, "for we have no safe full of jewels for you to rob. There are no keys to offices to be stolen from our pockets. And let me tell you—you are not the only man in New York who knows the secret of thermite. I have told the secret to the police, and they are only waiting to find who destroyed Morowitch's correspondence under the letter 'P' to apprehend the robber of his safe. Your secret is out."

"Revenge! revenge!" Poissan cried. "I will have revenge. Francois, bring out the jewels—ha! ha!—here in this bag are the jewels of Mr. Morowitch. To-night Francois and I will go down by the back elevator to a secret exit. In two hours all your police in New York cannot find us. But in two hours you two impostors will be suffocated—perhaps you will die of cyanogen, like Morowitch, whose jewels I have at last."

He went to the door into the hall and stood there with a mocking laugh. I moved to make a rush toward them, but Kennedy raised his hand.

"You will suffocate," Poissan hissed again.

Just then we heard the elevator door clang, and hurried steps came down the long hall.

Craig whipped out his automatic and began pumping the bullets out in rapid succession. As the smoke cleared I expected to see Poissan and Francois lying on the floor. Instead, Craig had fired at the lock of the door. He had shattered it into a thousand bits. Andrews and his men were running down the hall.

"Curse you!" muttered Poissan as he banged the now useless lock, "who let those fellows in? Are you a wizard?"

Craig smiled coolly as the ventilation cleared the room of the deadly cyanogen.

"On the window-sill outside is a selenium cell. Selenium is a bad conductor of electricity in the dark, and an excellent conductor when exposed to light. I merely moved my coat and hat, and the light from the furnace which was going to suffocate us played through the glass on the cell, the circuit was completed without your suspecting that I could communicate with friends outside, a bell was rung on the street, and here they are. Andrews, there is the murderer of Morowitch, and there in his hands are the Morowitch—"

Poissan had moved toward the furnace. With a quick motion he seized the long tongs. There was a cloud of choking vapour. Kennedy leaped to the switch and shut off the current. With the tongs he lifted out a shapeless piece of valueless black graphite.

"All that is left of the priceless Morowitch jewels," he exclaimed ruefully. "But we have the murderer."

"And to-morrow a certified check for one hundred thousand dollars goes to Mrs. Morowitch with my humblest apologies and sympathy," added Andrews. "Professor Kennedy, you have earned your retainer."



VII. The Azure Ring

Files of newspapers and innumerable clippings from the press bureaus littered Kennedy's desk in rank profusion. Kennedy himself was so deeply absorbed that I had merely said good evening as I came in and had started to open my mail. With an impatient sweep of his hand, however, he brushed the whole mass of newspapers into the waste-basket.

"It seems to me, Walter," he exclaimed in disgust, "that this mystery is considered insoluble for the very reason which should make it easy to solve—the extraordinary character of its features."

Inasmuch as he had opened the subject, I laid down the letter I was reading. "I'll wager I can tell you just why you made that remark, Craig," I ventured. "You're reading up on that Wainwright-Templeton affair."

"You are on the road to becoming a detective yourself, Walter," he answered with a touch of sarcasm. "Your ability to add two units to two other units and obtain four units is almost worthy of Inspector O'Connor. You are right and within a quarter of an hour the district attorney of Westchester County will be here. He telephoned me this afternoon and sent an assistant with this mass of dope. I suppose he'll want it back," he added, fishing the newspapers out of the basket again. "But, with all due respect to your profession, I'll say that no one would ever get on speaking terms with the solution of this case if he had to depend solely on the newspaper writers."

"No?" I queried, rather nettled at his tone.

"No," he repeated emphatically. "Here one of the most popular girls in the fashionable suburb of Williston, and one of the leading younger members of the bar in New York, engaged to be married, are found dead in the library of the girl's home the day before the ceremony. And now, a week later, no one knows whether it was an accident due to the fumes from the antique charcoal-brazier, or whether it was a double suicide, or suicide and murder, or a double murder, or—or—why, the experts haven't even been able to agree on whether they have discovered poison or not," he continued, growing as excited as the city editor did over my first attempt as a cub reporter.

"They haven't agreed on anything except that on the eve of what was, presumably, to have been the happiest day of their lives two of the best known members of the younger set are found dead, while absolutely no one, as far as is known, can be proved to have been near them within the time necessary to murder them. No wonder the coroner says it is simply a case of asphyxiation. No wonder the district attorney is at his wits' end. You fellows have hounded them with your hypotheses until they can't see the facts straight. You suggest one solution and before-"

The door-bell sounded insistently, and without waiting for an answer a tall, spare, loose-jointed individual stalked in and laid a green bag on the table.

"Good evening, Professor Kennedy," he began brusquely. "I am District Attorney Whitney, of Westchester. I see you have been reading up on the case. Quite right."

"Quite wrong," answered Craig. "Let me introduce my friend, Mr. Jameson, of the Star. Sit down. Jameson knows what I think of the way the newspapers have handled this case. I was about to tell him as you came in that I intended to disregard everything that had been printed, to start out with you as if it were a fresh subject and get the facts at first hand. Let's get right down to business. First tell us just how it was that Miss Wainwright and Mr. Templeton were discovered and by whom."

The district attorney loosened the cords of the green bag and drew out a bundle of documents. "I'll read you the affidavit of the maid who found them," he said, fingering the documents nervously. "You see, John Templeton had left his office in New York early that afternoon, telling his father that he was going to visit Miss Wainwright. He caught the three-twenty train, reached Williston all right, walked to the Wainwright house, and, in spite of the bustle of preparation for the wedding, the next day, he spent the rest of the afternoon with Miss Wainwright. That's where the mystery begins. They had no visitors. At least, the maid who answers the bell says they had none. She was busy with the rest of the family, and I believe the front door was not locked—we don't lock our doors in Williston, except at night."

He had found the paper and paused to impress these facts on our minds.

"Mrs. Wainwright and Miss Marian Wainwright, the sister, were busy about the house. Mrs. Wainwright wished to consult Laura about something. She summoned the maid and asked if Mr. Templeton and Miss Wainwright were in the house. The maid replied that she would see, and this is her affidavit. Ahem! I'll skip the legal part: 'I knocked at the library door twice, but obtaining no answer, I supposed they had gone out for a walk or perhaps a ride across country as they often did. I opened the door partly and looked in. There was a silence in the room, a strange, queer silence. I opened the door further and, looking toward the davenport in the corner, I saw Miss Laura and Mr. Templeton in such an awkward position. They looked as if they had fallen asleep. His head was thrown back against the cushions of the davenport, and on his face was a most awful look. It was discoloured. Her head had fallen forward on his shoulder, sideways, and on her face, too, was the same terrible stare and the same discolouration. Their right hands were tightly clasped.

"'I called to them. They did not answer. Then the horrible truth flashed on me. They were dead. I felt giddy for a minute, but quickly recovered myself, and with a cry for help I rushed to Mrs. Wainwright's room, shrieking that they were dead. Mrs. Wainwright fainted. Miss Marian called the doctor on the telephone and helped us restore her mother. She seemed perfectly cool in the tragedy, and I do not know what we servants should have done if she had not been there to direct us. The house was frantic, and Mr. Wainwright was not at home.

"'I did not detect any odour when I opened the library door. No glasses or bottles or vials or other receptacles which could have held poison were discovered or removed by me, or to the best of my knowledge and belief by anyone else.'"

"What happened next?" asked Craig eagerly.

"The family physician arrived and sent for the coroner immediately, and later for myself. You see, he thought at once of murder."

"But the coroner, I understand, thinks differently," prompted Kennedy.

"Yes, the coroner has declared the case to be accidental. He says that the weight of evidence points positively to asphyxiation. Still, how can it be asphyxiation? They could have escaped from the room at any time; the door was not locked. I tell you, in spite of the fact that the tests for poison in their mouths, stomachs, and blood have so far revealed nothing, I still believe that John Templeton and Laura Wainwright were murdered."

Kennedy looked at his watch thoughtfully. "You have told me just enough to make me want to see the coroner himself," he mused. "If we take the next train out to Williston with you, will you engage to get us a half-hour talk with him on the case, Mr. Whitney?"

"Surely. But we'll have to start right away. I've finished my other business in New York. Inspector O'Connor—ah, I see you know him—has promised to secure the attendance of anyone whom I can show to be a material witness in the case. Come on, gentlemen: I'll answer your other questions on the train."

As we settled ourselves in the smoker, Whitney remarked in a low voice, "You know, someone has said that there is only one thing more difficult to investigate and solve than a crime whose commission is surrounded by complicated circumstances and that is a crime whose perpetration is wholly devoid of circumstances."

"Are you so sure that this crime is wholly devoid of circumstances?" asked Craig.

"Professor," he replied, "I'm not sure of anything in this case. If I were I should not require your assistance. I would like the credit of solving it myself, but it is beyond me. Just think of it: so far we haven't a clue, at least none that shows the slightest promise, although we have worked night and day for a week. It's all darkness. The facts are so simple that they give us nothing to work on. It is like a blank sheet of paper."

Kennedy said nothing, and the district attorney proceeded: "I don't blame Mr. Nott, the coroner, for thinking it an accident. But to my mind, some master criminal must have arranged this very baffling simplicity of circumstances. You recall that the front door was unlocked. This person must have entered the house unobserved, not a difficult thing to do, for the Wainwright house is somewhat isolated. Perhaps this person brought along some poison in the form of a beverage, and induced the two victims to drink. And then, this person must have removed the evidences as swiftly as they were brought in and by the same door. That, I think, is the only solution."

"That is not the only solution. It is one solution," interrupted Kennedy quietly.

"Do you think someone in the house did it?" I asked quickly.

"I think," replied Craig, carefully measuring his words, "that if poison was given them it must have been by someone they both knew pretty well."

No one said a word, until at last I broke the silence. "I know from the gossip of the Star office that many Williston people say that Marian was very jealous of her sister Laura for capturing the catch of the season. Williston people don't hesitate to hint at it."

Whitney produced another document from that fertile green bag. It was another affidavit. He handed it to us. It was a statement signed by Mrs. Wainwright, and read:

"Before God, my daughter Marian is innocent. If you wish to find out all, find out more about the past history of Mr. Templeton before he became engaged to Laura. She would never in the world have committed suicide. She was too bright and cheerful for that, even if Mr. Templeton had been about to break off the engagement. My daughters Laura and Marian were always treated by Mr. Wainwright and myself exactly alike. Of course they had their quarrels, just as all sisters do, but there was never, to my certain knowledge, a serious disagreement, and I was always close enough to my girls to know. No, Laura was murdered by someone outside."

Kennedy did not seem to attach much importance to this statement. "Let us see," he began reflectively. "First, we have a young woman especially attractive and charming in both person and temperament. She is just about to be married and, if the reports are to be believed, there was no cloud on her happiness. Secondly, we have a young man whom everyone agrees to have been of an ardent, energetic, optimistic temperament. He had everything to live for, presumably. So far, so good. Everyone who has investigated this case, I understand, has tried to eliminate the double-suicide and the suicide-and-murder theories. That is all right, providing the facts are as stated. We shall see, later, when we interview the coroner. Now, Mr. Whitney, suppose you tell us briefly what you have learned about the past history of the two unfortunate lovers."

"Well, the Wainwrights are an old Westchester family, not very wealthy, but of the real aristocracy of the county. There were only two children, Laura and Marian. The Templetons were much the same sort of family. The children all attended a private school at White Plains, and there also they met Schuyler Vanderdyke. These four constituted a sort of little aristocracy in the school. I mention this, because Vanderdyke later became Laura's first husband. This marriage with Templeton was a second venture."

"How long ago was she divorced?" asked Craig attentively.

"About three years ago. I'm coming to that in a moment. The sisters went to college together, Templeton to law school, and Vanderdyke studied civil engineering. Their intimacy was pretty well broken up, all except Laura's and Vanderdyke's. Soon after he graduated he was taken into the construction department of the Central Railroad by his uncle, who was a vice-president, and Laura and he were married. As far as I can learn he had been a fellow of convivial habits at college, and about two years after their marriage his wife suddenly became aware of what had long been well known in Williston, that Vanderdyke was paying marked attention to a woman named Miss Laporte in New York.

"No sooner had Laura Vanderdyke learned of this intimacy of her husband," continued Whitney, "than she quietly hired private detectives to shadow him, and on their evidence she obtained a divorce. The papers were sealed, and she resumed her maiden name.

"As far as I can find out, Vanderdyke then disappeared from her life. He resigned his position with the railroad and joined a party of engineers exploring the upper Amazon. Later he went to Venezuela. Miss Laporte also went to South America about the same time, and was for a time in Venezuela, and later in Peru.

"Vanderdyke seems to have dropped all his early associations completely, though at present I find he is back in New York raising capital for a company to exploit a new asphalt concession in the interior of Venezuela. Miss Laporte has also reappeared in New York as Mrs. Ralston, with a mining claim in the mountains of Peru."

"And Templeton?" asked Craig. "Had he had any previous matrimonial ventures?"

"No, none. Of course he had had love affairs, mostly with the country-club set. He had known Miss Laporte pretty well, too, while he was in law school in New York. But when he settled down to work he seems to have forgotten all about the girls for a couple of years or so. He was very anxious to get ahead, and let nothing stand in his way. He was admitted to the bar and taken in by his father as junior member of the firm of Templeton, Mills & Templeton. Not long ago he was appointed a special master to take testimony in the get-rich-quick-company prosecutions, and I happen to know that he was making good in the investigation."

Kennedy nodded. "What sort of fellow personally was Templeton?" he asked.

"Very popular," replied the district attorney, "both at the country club and in his profession in New York. He was a fellow of naturally commanding temperament—the Templetons were always that way. I doubt if many young men even with his chances could have gained such a reputation at thirty-five as his. Socially he was very popular, too, a great catch for all the sly mamas of the country club who had marriageable daughters. He liked automobiles and outdoor sports, and he was strong in politics, too. That was how he got ahead so fast.

"Well, to cut the story short, Templeton met the Wainwright girls again last summer at a resort on Long Island. They had just returned from a long trip abroad, spending most of the time in the Far East with their father, whose firm has business interests in China. The girls were very attractive. They rode and played tennis and golf better than most of the men, and this fall Templeton became a frequent visitor at the Wainwright home in Williston.

"People who know them best tell me that his first attentions were paid to Marian, a very dashing and ambitious young woman. Nearly every day Templeton's car stopped at the house and the girls and some friend of Templeton's in the country club went for a ride. They tell me that at this time Marian always sat with Templeton on the front seat. But after a few weeks the gossips—nothing of that sort ever escapes Williston—said that the occupant of the front seat was Laura. She often drove the car herself and was very clever at it. At any rate, not long after that the engagement was announced."

As he walked up from the pretty little Williston station Kennedy asked: "One more question, Mr. Whitney. How did Marian take the engagement?"

The district attorney hesitated. "I will be perfectly frank, Mr. Kennedy," he answered. "The country-club people tell me that the girls were very cool toward each other. That was why I got that statement from Mrs. Wainwright. I wish to be perfectly fair to everyone concerned in this case."

We found the coroner quite willing to talk, in spite of the fact that the hour was late. "My friend, Mr. Whitney, here, still holds the poison theory," began the coroner, "in spite of the fact that everything points absolutely toward asphyxiation. If I had been able to discover the slightest trace of illuminating-gas in the room I should have pronounced it asphyxia at once. All the symptoms accorded with it. But the asphyxia was not caused by escaping illuminating-gas.

"There was an antique charcoal-brazier in the room, and I have ascertained that it was lighted. Now, anything like a brazier will, unless there is proper ventilation, give rise to carbonic oxide or carbon monoxide gas, which is always present in the products of combustion, often to the extent of from five to ten per cent. A very slight quantity of this gas, insufficient even to cause an odour in a room, will give a severe headache, and a case is recorded where a whole family in Glasgow was poisoned without knowing it by the escape of this gas. A little over one per cent of it in the atmosphere is fatal, if breathed for any length of time. You know, it is a product of combustion, and is very deadly—it is the much-dreaded white damp or afterdamp of a mine explosion.

"I'm going to tell you a secret which I have not given out to the press yet. I tried an experiment in a closed room today, lighting the brazier. Some distance from it I placed a cat confined in a cage so it could not escape. In an hour and a half the cat was asphyxiated."

The coroner concluded with an air of triumph that quite squelched the district attorney.

Kennedy was all attention. "Have you preserved samples of the blood of Mr. Templeton and Miss Wainwright?" he asked.

"Certainly. I have them in my office."

The coroner, who was also a local physician, led us back into his private office.

"And the cat?" added Craig.

Doctor Nott produced it in a covered basket.

Quickly Kennedy drew off a little of the blood of the cat and held it up to the light along with the human samples. The difference was apparent.

"You see," he explained, "carbon monoxide combines firmly with the blood, destroying the red colouring matter of the red corpuscles. No, Doctor, I'm afraid it wasn't carbonic oxide that killed the lovers, although it certainly killed the cat."

Doctor Nott was crestfallen, but still unconvinced. "If my whole medical reputation were at stake," he repeated, "I should still be compelled to swear to asphyxia. I've seen it too often, to make a mistake. Carbonic oxide or not, Templeton and Miss Wainwright were asphyxiated."

It was now Whitney's chance to air his theory.

"I have always inclined toward the cyanide-of-potassium theory, either that it was administered in a drink or perhaps injected by a needle," he said. "One of the chemists has reported that there was a possibility of slight traces of cyanide in the mouths."

"If it had been cyanide," replied Craig, looking reflectively at the two jars before him on the table, "these blood specimens would be blue in colour and clotted. But they are not. Then, too, there is a substance in the saliva which is used in the process of digestion. It gives a reaction which might very easily be mistaken for a slight trace of cyanide. I think that explains what the chemist discovered; no more, no less. The cyanide theory does not fit."

"One chemist hinted at nux vomica," volunteered the coroner. "He said it wasn't nux vomica, but that the blood test showed something very much like it. Oh, we've looked for morphine chloroform, ether, all the ordinary poisons, besides some of the little known alkaloids. Believe me, Professor Kennedy, it was asphyxia."

I could tell by the look that crossed Kennedy's face that at last a ray of light had pierced the darkness. "Have you any spirits of turpentine in the office?" he asked.

The coroner shook his head and took a step toward the telephone as if to call the drug-store in town.

"Or ether?" interrupted Craig. "Ether will do."

"Oh, yes, plenty of ether."

Craig poured a little of one of the blood samples from the jar into a tube and added a few drops of ether. A cloudy dark precipitate formed. He smiled quietly and said, half to himself, "I thought so."

"What is it?" asked the coroner eagerly. "Nux vomica?"

Craig shook his head as he stared at the black precipitate. "You were perfectly right about the asphyxiation, Doctor," he remarked slowly, "but wrong as to the cause. It wasn't carbon monoxide or illuminating-gas. And you, Mr. Whitney, were right about the poison, too. Only it is a poison neither of you ever heard of."

"What is it?" we asked simultaneously.

"Let me take these samples and make some further tests. I am sure of it, but it is new to me. Wait till to-morrow night, when my chain of evidence is completed. Then you are all cordially invited to attend at my laboratory at the university. I'll ask you, Mr. Whitney, to come armed with a warrant for John or Jane Doe. Please see that the Wainwrights, particularly Marian, are present. You can tell Inspector O'Connor that Mr. Vanderdyke and Mrs. Ralston are required as material witnesses—anything so long as you are sure that these five persons are present. Good night, gentlemen."

We rode back to the city in silence, but as we neared the station, Kennedy remarked: "You see, Walter, these people are like the newspapers. They are floundering around in a sea of unrelated facts. There is more than they think back of this crime. I've been revolving in my mind how it will be possible to get some inkling about this concession of Vanderdyke's, the mining claim of Mrs. Ralston, and the exact itinerary of the Wainwright trip in the Far East. Do you think you can get that information for me? I think it will take me all day to-morrow to isolate this poison and get things in convincing shape on that score. Meanwhile if you can see Vanderdyke and Mrs. Ralston you can help me a great deal. I am sure you will find them very interesting people."

"I have been told that she is quite a female high financier," I replied, tacitly accepting Craig's commission. "Her story is that her claim is situated near the mine of a group of powerful American capitalists, who are opposed to having any competition, and on the strength of that story she has been raking in the money right and left. I don't know Vanderdyke, never heard of him before, but no doubt he has some equally interesting game."

"Don't let them think you connect them with the case, however," cautioned Craig.

Early the next morning I started out on my quest for facts, though not so early but that Kennedy had preceded me to his work in his laboratory. It was not very difficult to get Mrs. Ralston to talk about her troubles with the government. In fact, I did not even have to broach the subject of the death of Templeton. She volunteered the information that in his handling of her case he had been very unjust to her, in spite of the fact that she had known him well a long time ago. She even hinted that she believed he represented the combination of capitalists who were using the government to aid their own monopoly and prevent the development of her mine. Whether it was an obsession of her mind, or merely part of her clever scheme, I could not make out. I noted, however, that when she spoke of Templeton it was in a studied, impersonal way, and that she was at pains to lay the blame for the governmental interference rather on the rival mine-owners.

It quite surprised me when I found from the directory that Vanderdyke's office was on the floor below in the same building. Like Mrs. Ralston's, it was open, but not doing business, pending the investigation by the Post-Office Department.

Vanderdyke was a type of which I had seen many before. Well dressed to the extreme, he displayed all those evidences of prosperity which are the stock in trade of the man with securities to sell. He grasped my hand when I told him I was going to present the other side of the post-office cases and held it between both of his as if he had known me all his life. Only the fact that he had never seen me before prevented his calling me by my first name. I took mental note of his stock of jewellery, the pin in his tie that might almost have been the Hope diamond, the heavy watch chain across his chest, and a very brilliant seal ring of lapis lazuli on the hand that grasped mine. He saw me looking at it and smiled.

"My dear fellow, we have deposits of that stuff that would make a fortune if we could get the machinery to get at it. Why, sir, there is lapis lazuli enough on our claim to make enough ultramarine paint to supply all the artists to the end of the world. Actually we could afford to crush it up and sell it as paint. And that is merely incidental to the other things on the concession. The asphalt's the thing. That's where the big money is. When we get started, sir, the old asphalt trust will simply melt away, melt away."

He blew a cloud of tobacco smoke and let it dissolve significantly in the air.

When it came to talking about the suits, however, Vanderdyke was not so communicative as Mrs. Ralston, but he was also not so bitter against either the post-office or Templeton.

"Poor Templeton," he said. "I used to know him years ago when we were boys. Went to school with him and all that sort of thing, you know, but until I ran across him, or rather he ran across me, in this investigation I hadn't heard much about him. Pretty clever fellow he was, too. The state will miss him, but my lawyer tells me that we should have won the suit anyhow, even if that unfortunate tragedy hadn't occurred. Most unaccountable, wasn't it? I've read about it in the papers for old time's sake, and can make nothing out of it."

I said nothing, but wondered how he could pass so lightheartedly over the death of the woman who had once been his wife. However, I said nothing. The result was he launched forth again on the riches of his Venezuelan concession and loaded me down with "literature," which I crammed into my pocket for future reference.

My next step was to drop into the office of a Spanish-America paper whose editor was especially well informed on South American affairs.

"Do I know Mrs. Ralston?" he repeated, thoughtfully lighting one of those black cigarettes that look so vicious and are so mild. "I should say so. I'll tell you a little story about her. Three or four years ago she turned up in Caracas. I don't know who Mr. Ralston was—perhaps there never was any Mr. Ralston. Anyhow, she got in with the official circle of the Castro government and was very successful as an adventuress. She has considerable business ability and represented a certain group of Americans. But, if you recall, when Castro was eliminated pretty nearly everyone who had stood high with him went, too. It seems that a number of the old concessionaires played the game on both sides. This particular group had a man named Vanderdyke on the anti-Castro side. So, when Mrs. Ralston went, she just quietly sailed by way of Panama to the other side of the continent, to Peru—they paid her well—and Vanderdyke took the title role.

"Oh, yes, she and Vanderdyke were very good friends, very, indeed. I think they must have known each other here in the States. Still they played their parts well at the time. Since things have settled down in Venezuela, the concessionaires have found no further use for Vanderdyke either, and here they are, Vanderdyke and Mrs. Ralston, both in New York now, with two of the most outrageous schemes of financing ever seen on Broad Street. They have offices in the same building, they are together a great deal, and now I hear that the state attorney-general is after both of them."

With this information and a very meagre report of the Wainwright trip to the Far East, which had taken in some out-of-the-way places apparently, I hastened back to Kennedy. He was surrounded by bottles, tubes, jars, retorts, Bunsen burners, everything in the science and art of chemistry, I thought.

I didn't like the way he looked. His hand was unsteady, and his eyes looked badly, but he seemed quite put out when I suggested that he was working too hard over the case. I was worried about him, but rather than say anything to offend him I left him for the rest of the afternoon, only dropping in before dinner to make sure that he would not forget to eat something. He was then completing his preparations for the evening. They were of the simplest kind, apparently. In fact, all I could see was an apparatus which consisted of a rubber funnel, inverted and attached to a rubber tube which led in turn into a jar about a quarter full of water. Through the stopper of the jar another tube led to a tank of oxygen.

There were several jars of various liquids on the table and a number of chemicals. Among other things was a sort of gourd, encrusted with a black substance, and in a corner was a box from which sounds issued as if it contained something alive.

I did not trouble Kennedy with questions, for I was only too glad when he consented to take a brisk walk and join me in a thick porterhouse.

It was a large party that gathered in Kennedy's laboratory that night, one of the largest he had ever had. Mr. and Mrs. Wainwright and Miss Marian came, the ladies heavily veiled. Doctor Nott and Mr. Whitney were among the first to arrive. Later came Mr. Vanderdyke and last of all Mrs. Ralston with Inspector O'Connor. Altogether it was an unwilling party.

"I shall begin," said Kennedy, "by going over, briefly, the facts in this case."

Tersely he summarised it, to my surprise laying great stress on the proof that the couple had been asphyxiated.

"But it was no ordinary asphyxiation," he continued. "We have to deal in this case with a poison which is apparently among the most subtle known. A particle of matter so minute as to be hardly distinguishable by the naked eye, on the point of a needle or a lancet, a prick of the skin scarcely felt under any circumstances and which would pass quite unheeded if the attention were otherwise engaged, and not all the power in the world—unless one was fully prepared—could save the life of the person in whose skin the puncture had been made."

Craig paused a moment, but no one showed any evidence of being more than ordinarily impressed.

"This poison, I find, acts on the so-called endplates of the muscles and nerves. It produces complete paralysis, but not loss of consciousness, sensation, circulation, or respiration until the end approaches. It seems to be one of the most powerful sedatives I have ever heard of. When introduced in even a minute quantity it produces death finally by asphyxiation—by paralysing the muscles of respiration. This asphyxia is what so puzzled the coroner.

"I will now inject a little of the blood serum of the victims into a white mouse."

He took a mouse from the box I had seen, and with a needle injected the serum. The mouse did not even wince, so lightly did he touch it, but as we watched, its life seemed gently to ebb away, without pain and without struggle. Its breath simply seemed to stop.