“Very well,” he agreed; “meet us at Mr. Lane’s office in half an hour.  Walter, see whether you can find Whiting.”

Whiting was one of Kennedy’s students with whom he had been lately conducting some experiments.  I hurried out and managed to locate him.

“What is it you suspect?” I asked, when we returned.  “A wreck—­ some spectacular stroke at the nations that are shipping the gold?”

“Perhaps,” he replied, absently, as he and Whiting hurriedly assembled some parts of instruments that were on a table in an adjoining room.

“Perhaps?” I repeated.  “What else might there be?”

“Robbery.”

“Robbery!” I exclaimed.  “Of twenty million dollars?  Why, man, just consider the mere weight of the metal!”

“That’s all very well,” he replied, warming up a bit as he saw that Whiting was getting things together quickly.  “But it needs only a bit of twenty millions to make a snug fortune—­” He paused and straightened up as the gathering of the peculiar electrical apparatus, whatever it was, was completed.  “And,” he went on quickly, “consider the effect on the stock-market of the news.  That’s the big thing.”

I could only gasp.

“A modern train-robbery, planned in the heart of dense traffic!”

“Why not?” he queried.  “Nothing is impossible if you can only take the other fellow unawares.  Our job is not to be taken unawares.  Are you ready, Whiting?”

“Yes, sir,” replied the student, shouldering the apparatus, for which I was very thankful, for my arms had frequently ached carrying about some of Kennedy’s weird but often weighty apparatus.

We piled into a taxicab and made a quick journey to the office of the Continental Express.  Maude Euston had already preceded us, and we found her standing by Lane’s desk as he paced the floor.

“Please, Miss Euston, don’t go,” he was saying as we entered.

“But I want to go,” she persisted, more than ever determined, apparently.

“I have engaged Professor Kennedy just for the purpose of foreseeing what new attack can be made on us,” he said.

“You have engaged Professor Kennedy?” she asked.  “I think I have a prior claim there, haven’t I?” she appealed.

Kennedy stood for a moment looking from one to the other.  What was there in the motives that actuated them?  Was it fear, hate, love, jealousy?

“I can serve my two clients only if they yield to me,” Craig remarked, quietly.  “Don’t set that down, Whiting.  Which is it—­yes or no?”

Neither Lane nor Miss Euston looked at each other for a moment.

“Is it in my hands?” repeated Craig.

“Yes,” bit off Lane, sourly.

“And you, Miss Euston?”

“Of course,” she answered.

“Then we all go,” decided Craig.  “Lane, may I install this thing in your telegraph-room outside?”

“Anything you say,” Lane returned, unmollified.