Almost immediately a waiter, bare-headed and wearing his white apron, came hurriedly out of the side door and got into the carriage, which instantly moved away at a rapid rate.
This incident struck Nick as being very peculiar. The waiter had acted like a man who was running away.
As he crossed the sidewalk he glanced hastily from side to side, as if afraid of being seen, and perhaps stopped.
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.