Dirty Dan hovered in the offing until Nan had registered and gone up to her room.  Immediately he registered also, and, while doing so, observed that Nan had signed her real name and given her address as Port Agnew, Washington.  With unexpected nicety, Dirty Dan decided not to embarrass her by registering from Port Agnew also, so he gave his address as Seattle.

For two days, he forgot the woes of Ireland and sat round the stuffy lobby, awaiting Nan Brent’s next move.  When he saw her at the cashier’s window paying out, he concealed himself behind a newspaper, and watched her covertly as the clerk gave instructions to the head porter regarding the disposition of her baggage.  The instant she left the hotel, accompanied by her child, Dirty Dan approached the porter and said with an insinuating smile: 

“I’d give a dollar to know the address the young lady wit’ the baby bhoy give you f’r the delivery av her trunk.”

The porter reached for the dollar and handed Dirty Dan a shipping tag containing the address.  Mr. O’Leary laboriously wrote the address in a filthy little memorandum-book, and that afternoon made a point of looking up Nan’s new habitation.  He discovered it to be an old brownstone front in lower Madison Avenue, and a blue-and-gold sign over the area fence indicated to Mr. O’Leary that, from an abode of ancient New York aristocracy, the place had degenerated into a respectable boarding-house.

“’Tis true,” Dirty Dan murmured.  “She’s given the young fella the go-by.  Hurro!  An’ I’m bettin’ I’m the only lad in the wide, wide wurrld that knows where she’s gone.  Faith, but wouldn’t Misther Donald pay handsomely for the information in me little book.”

Having, as he judged, followed the mystery to its logical conclusion, Mr. O’Leary was sensible of a sudden waning of his abnormal curiosity in Nan Brent’s affairs.  He acknowledged to himself that he had spent time and money on a matter that was absolutely none of his business, but excused himself upon the ground that if he hadn’t investigated the matter thoroughly, his failure to do so might annoy him in the future.  If, for no other reason than the desirability of being on the inside track of this little romance of a rich man’s son, his action was to be commended.  People have no business disappearing without leaving a trace or saying good-by to those that love them.  Dirty Dan hadn’t the least idea of selling his information to Donald McKaye, but something in his peculiar mental make-up caused him to cherish a secret for its own sake; he had a true Irishman’s passion for being “in the know,” and now that he was in it, he was tremendously satisfied with himself and dismissed the entire matter from his mind.  Old Ireland and her woes were again paramount, so Mr. O’Leary presented himself before the proper authorities and applied for a passport to visit Ireland.

Now, while Daniel J. did not know it, one of the first questions the applicant for a passport is required to answer is his reason for desiring to make the journey, and during the Great War, as everybody of mature years will recall, civilians were not permitted to subject themselves to the dangers of a ruthless submarine war without good and sufficient reason.  Mr. O’Leary had a reason—­to his way of thinking, the noblest reason in all the world; consequently he was proud of it and not at all inclined to conceal it.