“Murderers!  Murderers!  None other than murderers!”

I paused in the reading.  “There’s nothing here,” I remarked, glancing over the curious document for a clue, but finding none.

“Well,” remarked Craig contemplatively, “one can at least easily understand how sensitive and imaginative people who have fallen under the influence of one who writes in that way can feel justified in killing those responsible for bringing such horrors on the human race.  Hello—­what’s this?”

He had discovered a false back of one of the drawers in the desk and had jimmied it open.  On the top of innumerable papers lay a large linen envelope.  On its face it bore in typewriting, just like the card on the drawer at Fortescue’s, “E-M gun.”

“It is the original envelope that contained the final plans of the electro-magnetic gun,” he explained, opening it.

The envelope was empty.  We looked at each other a moment in silence.  What had been done with the plans?

Suddenly a bell rang, startling me beyond measure.  It was, however, only the telephone, of which an extension reached up into the attic-arsenal.  Some one, who did not know that we were there, was evidently calling up.

Kennedy quickly unhooked the receiver with a hasty motion to me to be silent.

“Hello,” I heard him answer.  “Yes, this is it.”

He had disguised his voice.  I waited anxiously and watched his face to gather what response he received.

“The deuce!” he exclaimed, with his hand over the transmitter so that his voice would not be heard at the other end of the line.

“What’s the matter?” I asked eagerly.

“It was Mrs. Annenberg—­I am sure.  But she was too keen for me.  She caught on.  There must be some password or form of expression that they use, which we don’t know, for she hung up the receiver almost as soon as she heard me.”

Kennedy waited a minute or so.  Then he whistled into the transmitter.  It was done apparently to see whether there was anyone listening.  But there was no answer.

“Operator, operator!” he called insistently, moving the hook up and down.  “Yes, operator.  Can you tell me what number that was which just called?”

He waited impatiently.

“Bleecker—­7l80,” he repeated after the girl.  “Thank you.  Information, please.”

Again we waited, as Craig tried to trace the call up.

“What is the street address of Bleecker, 7180?” he asked.  “Five hundred and one East Fifth—­a tenement.  Thank you.”

“A tenement?” I repeated blankly.

“Yes,” he cried, now for the first time excited.  “Don’t you begin to see the scheme?  I’ll wager that Baron Kreiger has been lured to New York to purchase the electro-magnetic gun which they have stolen from Fortescue and the British.  That is the bait that is held out to him by the woman.  Call up Miss Lowe at the laboratory and see if she knows the place.”