w was to keep Mr. Wynne in sight, so he came down the steps and
walked rapidly on to Sixty-seventh Street, pausing to peer around the
corner before he turned. Mr. Wynne was idling along, half a block
away, without the slightest apparent interest in what was happening
behind. Inevitably Mr. Birnes' eyes were drawn to the water-plug
across the street. A tag end of white paper gleamed tantalizingly.
Now what the deuce did it mean?

Being only human, Mr. Birnes went across the street and got the
paper. It was an envelope. As he unfolded it and gazed at the
address, written in pencil, his mouth opened in undignified
astonishment. It was addressed to him--Steve Birnes, Chief of the
Birnes Detective Agency. Mr. Wynne had still not looked back, so
the detective trailed along behind, opening the envelope as he
walked. A note inside ran briefly:

My address is No. ---- East Thirty-seventh Street. If it is
necessary for you to see me please call there about six o'clock
this afternoon.
E. VAN CORTLANDT WYNNE

Now here was, perhaps, as savory a kettle of fish as Mr. Birnes had
ever stumbled upon. It is difficult to imagine a more embarrassing
situation for the professional sleuth than to find himself suddenly
taken into the confidence of the person he is shadowing. But _was_
he being taken into Mr. Wynne's confidence? Ah! That was the
question! Admitting that Mr. Wynne knew who he was, and admitting
that he knew he was being followed, was not this apparent frankness
an attempt to throw him off the scent? He would see, would Mr.
Birnes.

He quickened his pace a little, then slowed up instantly, because Mr.
Wynne had stopped on the corner of Madison Avenue, and as a downtown
car came rushing along he stepped out to board it. Mr. Birnes
scuttled across the street, and by a dexterous jump swung on the car
as it fled past. Mr. Wynne had gone forward and was taking a seat;
Mr. Birnes remained on the back platform, sheltered by the
accommodating bulk of a fat man, and flattered himself that Mr.
Wynne had not seen him. By peering over a huge shoulder the
detective was still able to watch Mr. Wynne.

He saw him pay his fare, and then he saw him place the small
sole-leather grip on his knees and unfasten the catch. Not knowing
what was in that grip Mr. Birnes was curious to see what came out of
it. Nothing came out of it--it was empty! There was no question of
this, for Mr. Wynne opened it wide and turn