I want to be free to make the connection outside with that wire in the shaft."
Imagine our surprise, the next morning, when a tap at our door revealed Loraine Keith herself.
"Is this Professor Kennedy?" she asked, gazing at us with a half-wild expression which she was making a tremendous effort to control. "Because if it is, I have something to tell him that may interest Mr. Carton."
We looked at her curiously. Without her make-up she was pallid and yellow in spots, her hands trembling, cold, and sweaty, her eyes sunken and glistening, with pupils dilated, her breathing short and hurried, restless, irresolute, and careless of her personal appearance.
"Perhaps you wonder how I heard of you and why I have come to you," she went on. "It is because I have a confession to make. I saw Mr. Haddon just before he was—kidnapped."
She seemed to hesitate over the word.
"How did you know I was interested?" asked Kennedy keenly.
"I heard him mention your name with Mr. Carton's."
"Then he knew that I was more than a reporter for the Star," remarked Kennedy. "Kidnapped, you say? How?"
She shot a glance half of suspicion, half of frankness, at us.
"That's what I must confess. Whoever did it must have used me as a tool. Mr. Haddon and I used to be good friends—I would be yet."
There was evident feeling in her tone which she did not have to assume. "All I remember yesterday was that, after lunch, I was in the office of the Mayfair when he came in. On his desk was a package. I don't know what has become of it. But he gave one look at it, seemed to turn pale, then caught sight of me. 'Loraine,' he whispered, 'we used to be good friends. Forgive me for turning you down. But you don't understand. Get me away from here—come with me—call a cab.'
"Well, I got into the cab with him. We had a chauffeur whom we used to have in the old days. We drove furiously, avoiding the traffic men. He told the driver to take us to my apartment—and—and that is the last I remember, except a scuffle in which I was dragged from the cab on one side and he on the other."
She had opened her handbag and taken from it a little snuff-box, like that which we had seen in the den.
"I—I can't go on," she apologised, "without this stuff."
"So you are a cocaine fiend, also?" remarked Kennedy.
"Yes, I can't help it. There is an indescribable excitement to do something great, to make a mark, that goes with it. It's soon gone, but while it lasts I can sing and dance, do anything until every part of my body begins crying for it again. I was full of the stuff when this happened yesterday; had taken too much, I guess."
The change in her after she had snuffed some of the crystals was magical. From a quivering wretch she had become now a self-confident neurasthenic.
"You know where that stuff will land you, I presume?" questioned Kennedy.
"I don't care," she laughed hollowly. "Yes, I know what you are going to tell me. Soon I'll be hunting for the cocaine bug, as they call it, imagining that in my skin, under the flesh, are worms crawling, perhaps see them, see the little animals running around and biting me. Oh, you don't know. There are two souls to the cocainist. One is tortured by the suffering which the stuff brings; the other laughs at the fears and pains. But it brings such thoughts! It stimulates my mind, makes it work without, against my will, gives me such visions—oh, I can not go on. They would kill me if they knew I had come to you. Why have I? Has not Haddon cast me off? What is he to me, now?"
It was evident that she was growing hysterical. I wondered whether, after all, the story of the kidnapping of Haddon might not be a figment of her brain, simply an hallucination due to the drug.
"They?" inquired Kennedy, observing her narrowly. "Who?"
"I can't tell. I don't know. Why did I come? Why did I come?"
She was reaching again for the snuff-box, but Kennedy restrained her.
"Miss Keith," he remarked, "you are concealing something from me. There is some one," he paused a moment, "whom you are shielding."
"No, no," she cried. "He was taken. Brodie had nothing to do with it, nothing. That is what you mean. I know. This stuff increases my sensitiveness. Yet I hate Coke Brodie—oh—let me go. I am all unstrung. Let me see a doctor. To-night, when I am better, I will tell all."
Loraine Keith had torn herself from him, had instantly taken a pinch of the fatal crystals, with that same ominous change from fear to self-confidence. What had been her purpose in coming at all? It had seemed at first to implicate Brodie, but she had been quick to shield him when she saw that danger. I wondered what the fascination might be which the wretch exercised over her.
"To-night—I will see you to-night," she cried, and a moment later she was gone, as unexpectedly as she had come.
I looked at Kennedy blankly.
"What was the purpose of that outburst?" I asked.
"I can't say," he replied. "It was all so incoherent that, from what I know of drug fiends, I am sure she had a deep-laid purpose in it all. It does not change my plans."
Two hours later we had paid a deposit on an empty flat in the tenement-house in which the bomb-maker had his headquarters, and had received a key to the apartment from the janitor. After considerable difficulty, owing to the narrowness of the air-shaft, Kennedy managed to pick up the loose ends of the wire which had been led out of the little window at the base of the shaft, and had attached it to a couple of curious arrangements which he had brought with him. One looked like a large taximeter from a motor cab; the other was a diminutive gas-metre, in looks at least. Attached to them were several bells and lights.
He had scarcely completed installing the thing, whatever it was, when a gentle tap at the door startled me. Kennedy nodded, and I opened it. It was Carton.
"I have had my men watching the Mayfair," he announced. "There seems to be a general feeling of alarm there, now. They can't even find Loraine Keith. Brodie, apparently, has not shown up in his usual haunts since the episode of last night."
"I wonder if the long arm of this vice trust could have reached out and gathered them in, too?" I asked.
"Quite likely," replied Carton, absorbed in watching Kennedy. "What's this?"
A little bell had tinkled sharply, and a light had flashed up on the attachments to the apparatus.
"Nothing. I was just testing it to see if it works. It does, although the end which I installed down below was necessarily only a makeshift. It is not this red light with the shrill bell that we are interested in. It is the green light and the low-toned bell. This is a thermopile."
"And what is a thermopile?" queried Carton.
"For the sake of one who has forgotten his physics," smiled Kennedy, "I may say this is only another illustration of how all science ultimately finds practical application. You probably have forgotten that when two half-rings of dissimilar metals are joined together and one is suddenly heated or chilled, there is produced at the opposite connecting point a feeble current which will flow until the junctures are both at the same temperature. You might call this a thermo-electric thermometer, or a telethermometer, or a microthermometer, or any of a dozen names."
"Yes," I agreed mechanically, only vaguely guessing at what he had in mind.
"The accurate measurement of temperature is still a problem of considerable difficulty," he resumed, adjusting the thermometer. "A heated mass can impart vibratory motion to the ether which fills space, and the wave-motions of ether are able to reproduce in other bodies motions similar to those by which they are caused. At this end of the line I merely measure the electromotive force developed by the difference in temperature of two similar thermo-electric junctions, opposed. We call those junctions in a thermopile 'couples,' and by getting the recording instruments sensitive enough, we can measure one one-thousandth of a degree.
"Becquerel was the