et in touch with George Westlake, third vice-president of the
telephone company. Westlake got busy."

Delaney eyed his unpolished shoes with a sage wink.

"Westlake turned things over," continued the detective. "He made a most
thorough investigation. We have his word that there is no record of
this call! The wire-chief at Gramercy Hill Exchange declares that it
never went through the switchboard. That the connection had been made
on the outside."

"From the air?"

"Looks that way. They tried everything and questioned everybody. No one
talked with Stockbridge through the switchboard at Gramercy Hill, at or
near that hour. Therefore, we must conclude, that, insomuch as I know
somebody _did_ talk with him at that hour, the connection was made,
either in the junction-box in the alley or behind the switchboard at
Gramercy Hill Exchange."

"How about underground, Chief?"

"Impossible! That is--almost impossible. The cables are in conduit and
sheathed with lead. It would be a poor place to tap in on a line. I'm
going to presume that the man who tapped in knew his business. The
junction-box in the alley is under suspicion. I think it was done
there, in this manner." Drew paused and picked up a third sheet of
hurriedly-written notes.

"A junction-box," he said, "is merely a small switchboard where the
conduit ends and the house connections begin. It would have been easy
for an expert to disconnect the two leads which led into Stockbridge's
library, ring up with a low tension magneto, and then cut in with a
testing set and a battery current and do the talking. That is what the
trouble-man told us might have been done. He found no signs of
tampering. He saw a tall man escaping down the alley. It would seem,
Delaney, that this tall man is the one we're after. Perhaps, as you
said, he left footprints. But footprints, like fingerprints, are not
much use until you get the man who made them."

"What d'ye deduct in this second call--Chief?"

"That we've run squarely up against a blind wall. We'll drop it for a
time and go to the third call."

"When was that?"

"Stockbridge was murdered at four minutes and eighteen seconds past
twelve, by his own watch, Delaney. It was a very good watch! Now
allowing for a movement of the hands on account of the fall, how are we
to account for a telephone call sent into Gramercy Hill 9763--the
library 'phone--at exactly five minutes past twelve from a
slot-telephone booth at the east end o