He seemed to want to say no more on the subject, from which I took it that he had discovered nothing of importance.

“One thing, though,” he recollected, after a moment.  “He has been going to see Inez Mendoza, they tell me.”

“Yes?” queried Kennedy.

“Confound him.  He pretty nearly got Lockwood in bad with her, too,” said Whitney, then leaning over confidentially added, “Say, Kennedy, honestly, now, you don’t believe that shoe-print stuff, do you?”

“I see no reason to doubt it,” returned Kennedy with diplomatic firmness.  “Why?”

“Well,” continued Whitney, still confidential, “we haven’t got the dagger—­that’s all.  There—­I never actually asserted that before, though I’ve given every one to understand that our plans are based on something more than hot-air.  We haven’t got it, and we never had it.”

“Then who has it?” asked Kennedy colourlessly.

Whitney shook his head.  “I don’t know,” he said merely.

“And these attacks on you—­this cigarette business—­how do you explain that,” asked Craig, “if you haven’t the dagger?”

“Jealousy, pure jealousy,” replied Whitney quickly.  “They are so afraid that we will find the treasure.  That’s my dope.”

“Who is afraid?”

“That’s a serious matter,” he evaded.  “I wouldn’t say anything that I couldn’t back up in a case of that kind.  I’d get into trouble.”

There was nothing to be gained by prolonging the conversation and Kennedy made a move as though to go.

“Just give us a square deal,” said Whitney as we left.  “That’s all we want—­a square deal.”

Kennedy and I walked out of the Prince Edward Albert and turned down the block.

“Well, have you found out anything more?” asked a voice in the shadow beside us.

We turned.  It was Norton.

“I saw you talking to Whitney in the writing-room,” he said, with a laugh, “then in the cafe, and I saw Alfonso come in.  He still has those shadows on me.  I wouldn’t be surprised if there was one of them around in a doorway, now.”

“No,” returned Kennedy, “he didn’t say anything that was important.  They still say they haven’t the dagger.”

“Of course,” said Norton.

“You’ll wait around a little longer?” asked Kennedy as we came to a corner and stopped.

“I think so,” returned Norton.  “I’ll keep you posted.”

Kennedy and I walked on a bit.

“I’m going around to see how Burke, O’Connor’s man, is getting on watching the Mendoza apartment, Walter,” he said at length.  “Then I have two or three other little outside matters to attend to.  You look tired.  Why don’t you go home and take a rest?  I shan’t be working in the laboratory to-night, either.”

“I think I will,” I agreed, for the strain of the case was beginning to tell on me.

XX

THE PULMOTOR