It looked as if the waiter might have robbed one of the restaurant's
patrons, or possibly its proprietor. If Nick had had no business on his
hands he would have followed that carriage.

As it happened, however, the man for whom the detective was watching
appeared at that moment.

Nick was obliged to follow him, but he knew that he would not have to go
far, for Chick was waiting on Sixth avenue, and it was in that direction
that the thief turned.

So it happened that within ten minutes Nick was able to turn this case
over to his famous assistant, and return to clear up the mystery of the
queer incident which he had chanced to observe.

Nick would not have been surprised to find the restaurant in an uproar,
but it was as quiet as usual. He entered by the side door, ascended a
flight of stairs, and came to a sort of office with a desk and a
register.

It was the custom of the place that guests should put down their names
as in a hotel before being assigned to a private dining-room.

There was nobody in sight.

The hall led toward the front of the building, and there were three
rooms on the side of it toward the street.

All the doors were open and the rooms were empty. Nick glanced into
these rooms, and then turned toward the desk. As he did so he saw a
waiter coming down the stairs from the floor above.

This man was known by the name of Gaspard. He was the head waiter, and
was on duty in the lower hall.

"Ah, Gaspard," said Nick, "who's your waiter on this floor to-night?"

Gaspard looked at Nick anxiously. He did not, of course, know who the
detective really was, but he remembered him as one who had assisted the
police in a case in which that house had been concerned about two years
before.

"Jean Corbut," replied Gaspard. "I hope nothing is wrong."

"That remains to be seen," said Nick. "What sort of a man is this
Corbut?"

"A little man," answered Gaspard, "and very thin. He has long, black
hair, and mustaches pointed like two needles."

"Have you sent him out for anything?"

"Oh, no; he is here."

"Where?"

"In one of the rooms at the front. We have parties in A and B."

"You go and find him," said Nick. "I want to see him right away."

Gaspard went to the front of the house. A hall branched off at right
angles with that in which Nick was standing. On the second hall were
three rooms, A, B and C.

Room C was next the avenue. The other two had windows on an open space
between two wings of t