She looked worn and haggard. She had spent a sleepless night and begged that Kennedy would not ask her to repeat the experiment.

"I can promise you, Marie," he said, "that you will rest better to-night. But you must spend one more night in Mrs. Close's room. By the way, can you arrange for me to go through the room this morning when you go back?"

Marie said she could, and an hour or so later Craig and I quietly slipped into the Close residence under her guidance. He was carrying something that looked like a miniature barrel, and I had another package which he had given me, both carefully wrapped up. The butler eyed us suspiciously, but Marie spoke a few words to him and I think showed him Mrs. Close's note. Anyhow he said nothing.

Within the room that the unfortunate woman had occupied Kennedy took the coverings off the packages. It was nothing but a portable electric vacuum cleaner, which he quickly attached and set running. Up and down the floor, around and under the bed he pushed the cleaner. He used the various attachments to clean the curtains, the walls, and even the furniture. Particularly did he pay attention to the base board on the wall back of the bed. Then he carefully removed the dust from the cleaner and sealed it up in a leaden box.

He was about to detach and pack up the cleaner when another idea seemed to occur to him. "Might as well make a thorough job of it, Walter," he said, adjusting the apparatus again. "I've cleaned everything but the mattress and the bra.s.s bars behind the mattress on the bed. Now I'll tackle them. I think we ought to go into the suction-cleaning business--more money in it than in being a detective, I'll bet."

The cleaner was run over and under the mattress and along every crack and cranny of the bra.s.s bed. This done and this dust also carefully stowed away, we departed, very much to the mystification of Marie and, I could not help feeling, of other eyes that peered in through keyholes or cracks in doors.

"At any rate," said Kennedy exultingly, "I think we have stolen a march on them. I don't believe they were prepared for this, not at least at this stage in the game. Don't ask me any questions, Walter.

Then you will have no secrets to keep if anyone should try to pry them loose. Only remember that this man Lawrence is a shrewd character."

The next day Marie came, looking even more careworn than before.

"What's the matter, mademoiselle?" asked Craig. "Didn't you pa.s.s a better night?"

"Oh, mon Dieu, I rest well, yes. But this morning while I am at breakfast, Mr. Close send for me. He say that I am discharged. Some servant tell of your visit and he ver-ry angr-ry. And now what is to become of me--will madame his wife give a recommendation now?"

"Walter, we have been discovered," exclaimed Craig with considerable vexation. Then he remembered the poor girl who had been an involuntary sacrifice to our investigation. Turning to her he said: "Marie, I know several very good families, and I am sure you will not suffer for what you have done by being faithful to your mistress. Only be patient a few days. Go live with some of your folks. I will see that you are placed again."

The girl was profuse in her thanks as she dried her tears and departed.

"I hadn't antic.i.p.ated having my hand forced so soon," said Craig after she had gone, leaving her address. "However, we are on the right track. What was it that you were going to tell me when Marie came in?"

"Something that may be very important, Craig," I said, "though I don't understand it myself. Pressure is being brought to bear on the _Star_ to keep this thing out of the papers, or at least to minimize it."

"I'm not surprised," commented Craig. "What do you mean by pressure being brought?"

"Why, Close's lawyer, Lawrence, called up the editor this morning--I don't suppose that you know, but he has some connection with the interests which control the _Star_--and said that the activity of one of the reporters from the _Star_, Jameson by name, was very distasteful to Mr. Close and that this reporter was employing a man named Kennedy to a.s.sist him.

"I don't understand it, Craig," I confessed, "but here one day they give the news to the papers, and two days later they almost threaten us with suit if we don't stop publishing it."

"It is perplexing," said Craig, with the air of one who was not a bit perplexed, but rather enlightened.

He pulled down the district telegraph messenger lever three times, and we sat in silence for a while.

"However," he resumed, "I shall be ready for them to-night."

I said nothing. Several minutes elapsed. Then the messenger rapped on the door.

"I want these two notes delivered right away," said Craig to the boy; "here's a quarter for you. Now mind you don't get interested in a detective story and forget the notes. If you are back here quickly with the receipts I'll give you another quarter. Now scurry along."

Then, after the boy had gone, he said casually to me: "Two notes to Close and Gregory, asking them to be present with their attorneys to-night. Close will bring Lawrence, and Gregory will bring a young lawyer named Asche, a very clever fellow. The notes are so worded that they can hardly refuse the invitation."

Meanwhile I carried out an a.s.signment for the _Star_, and telephoned my story in so as to be sure of being with Craig at the crucial moment. For I was thoroughly curious about his next move in the game.

I found him still in his laboratory attaching two coils of thin wire to the connections on the outside of a queer-looking little black box.

"What's that?" I asked, eyeing the sinister-looking little box suspiciously. "An infernal machine? You're not going to blow the culprit into eternity, I hope."

"Never mind what it is, Walter. You'll find that out in due time. It may or it may not be an infernal machine--of a different sort than any you have probably ever heard of. The less you know now the less likely you are to give anything away by a look or an act. Come now, make yourself useful as well as ornamental. Take these wires and lay them in the cracks of the floor, and be careful not to let them show. A little dust over them will conceal them beautifully."

Craig now placed the black box back of one of the chairs well down toward the floor, where it could hardly have been perceived unless one were suspecting something of the sort. While he was doing so I ran the wires across the floor, and around the edge of the room to the door.

"There," he said, taking the wires from me. "Now I'll complete the job by carrying them into the next room. And while I'm doing it, go over the wires again and make sure they are absolutely concealed."

That night six men gathered in Kennedy's laboratory. In my utter ignorance of what was about to happen I was perfectly calm, and so were all the rest, except Gregory. He was easily the most nervous of us all, though his lawyer Asche tried repeatedly to rea.s.sure him.

"Mr. Close," began Kennedy, "if you and Mr. Lawrence will sit over here on this side of the room while Dr. Gregory and Mr. Asche sit on the opposite side with Mr. Jameson in the middle, I think both of you opposing parties will be better suited. For I apprehend that at various stages in what I am about to say both you, Mr. Close, and you Dr. Gregory, will want to consult your attorneys. That, of course, would be embarra.s.sing, if not impossible, should you be sitting near each other. Now, if we are ready, I shall begin."

Kennedy placed a small leaden casket on the table of his lecture hall.

"In this casket," he commenced solemnly, "there is a certain substance which I have recovered from the dust swept up by a vacuum cleaner in the room of Mrs. Close."

One could feel the very air of the room surcharged with excitement.

Craig drew on a pair of gloves and carefully opened the casket. With his thumb and forefinger he lifted out a gla.s.s tube and held it gingerly at arm's length. My eyes were riveted on it, for the bottom of the tube glowed with a dazzling point of light.

Both Gregory and his attorney and Close and Lawrence whispered to each other when the tube was displayed, as indeed they did throughout the whole exhibition of Kennedy's evidence.

"No infernal machine was ever more subtle," said Craig, "than the tube which I hold in my hand. The imagination of the most sensational writer of fiction might well be thrilled with the mysteries of this fatal tube and its power to work fearful deed. A larger quant.i.ty of this substance in the tube would produce on me, as I now hold it, incurable burns, just as it did on its discoverer before his death.

A smaller amount, of course, would not act so quickly. The amount in this tube, if distributed about, would produce the burns inevitably, providing I remained near enough for a long-enough time."

Craig paused a moment to emphasize his remarks.

"Here in my hand, gentlemen, I hold the price of a woman's beauty."

He stopped again for several moments, then resumed.

"And now, having shown it to you, for my own safety I will place it back in its leaden casket."

Drawing off his gloves, he proceeded.

"I have found out by a cablegram to-day that seven weeks ago an order for one hundred milligrams of radium bromide at thirty-five dollars a milligram from a certain person in America was filled by a corporation dealing in this substance."

Kennedy said this with measured words, and I felt a thrill run through me as he developed his case.

"At that same time, Mrs. Close began a series of treatments with an X-ray specialist in New York," pursued Kennedy. "Now, it is not generally known outside scientific circles, but the fact is that in their physiological effects the X-ray and radium are quite one and the same. Radium possesses this advantage, however, that no elaborate apparatus is necessary for its use. And, in addition, the emanation from radium is steady and constant, whereas the X-ray at best varies slightly with changing conditions of the current and vacuum in the X-ray tube. Still, the effects on the body are much the same.

"A few days before this order was placed I recall the following despatch which appeared in the New York papers. I will read it:

"'Liege, Belgium, Oct.--, 1910. What is believed to be the first criminal case in which radium figures as a death-dealing agent is engaging public attention at this university town. A wealthy old bachelor, Pailin by name, was found dead in his flat. A stroke of apoplexy was at first believed to have caused his death, but a close examination revealed a curious discoloration of his skin. A specialist called in to view the body gave as his opinion that the old man had been exposed for a long time to the emanations of X-ray or radium.

The police theory is that M. Pailin was done to death by a systematic application of either X-ray or radium by a student in the university who roomed next to him. The student has disappeared.'

"Now here, I believe, was the suggestion which this American criminal followed, for I cut it out of the paper rather expecting sooner or later that some clever person would act on it. I have thoroughly examined the room of Mrs. Close. She herself told me she never wanted to return to it, that her memory of sleepless nights in it was too vivid. That served to fix the impression that I had already formed from reading this clipping. Either the X-ray or radium had caused her dermat.i.tis and nervousness. Which was it? I wished to be sure that I would make no mistake. Of course I knew it was useless to look for an X-ray machine in or near Mrs. Close's room. Such a thing could never have been concealed. The alternative? Radium! Ah! that was different.

I determined on an experiment. Mrs. Close's maid was prevailed on to sleep in her mistress's room. Of course radiations of brief duration would do her no permanent harm, although they would produce their effect, nevertheless. In one night the maid became extremely nervous.