the supposed electrician replaced it and rose to his feet, saying:
"There, I've finished now."

Franz did not recognise the double meaning in the words. "Yes, it's all
right! I've finished here now," Muller repeated to himself. For now he
knew beyond a doubt that the red light was a signal--and he knew
also for whom this signal was intended. It was a signal for Herbert
Thorne!--Herbert Thorne, whom no single thought or suspicion of Muller's
had yet connected with the murder of Leopold Winkler.

The detective was very much surprised and greatly excited. But Franz did
not notice it, and indeed a far keener observer than the slow-witted old
butler might have failed to see the sudden gleam which shot up in the
grey eyes behind the heavy spectacles, might have failed to notice the
tightening of the lips beneath the blond moustache, or the tenseness of
the slight frame under the assumed embonpoint. Muller's every nerve was
tingling, but he had himself completely in hand.

"What do we owe you?" asked Franz.

"They'll send you a bill from the office. It won't amount to much. I
must be getting on now."

Muller hastened out of the door and down the street to the nearest cab
stand. There were not very many cab stands in this vicinity, and the
detective reasoned that Mrs. Bernauer would naturally have taken her
cab from the nearest station. He had heard her return in her carriage,
presumably the same in which she had started out.

There was but one cab at the stand. Muller walked to it and laid his
hand on the door.

"Oh, Jimmy! must I go out again?" asked the driver hoarsely. "Can't you
see the poor beast is all wet from the last ride? We've just come in."
He pointed with his whip to the tired-looking animal under his blanket.

"Why, he does look warm. You must have been making a tour out into the
country," said the blond gentleman in a friendly tone.

"No, sir, not quite so far as that. I've just taken a woman to the main
telegraph office in the city and back again. But she was in a hurry and
he's not a young horse, sir."

"Well, never mind, then; I can get another cab across the bridge,"
replied the stout blond man, turning away and strolling off leisurely
in the direction of the bridge. It was now quite dark, and a few
steps further on Muller could safely turn and take the road to his own
lodging. No one saw him go in, and in a few moments the real Muller,
slight, smooth-shaven, sat down at his desk, looking at the