“Thanks,” returned Dick, and headed for the place in question, with Tom and Sam at his heels.

An officer was in charge of the office of the harbor police and he listened with interest to what the boys had to tell.

“This is certainly a serious matter,” he said, when they had finished.  “Those men are actually kidnapping your father—­ in fact, they have already kidnapped him.  We’ll have to get after them.”

“You have a boat handy?”

“Yes, several of ’em.”

The officer touched a bell and another man in uniform appeared.  He was given some instructions, and then the second man told the Rover boys to follow him.  He led the way to a dock where a steam tug lay, the smoke pouring from the funnel.

“Quick work here, Andy!” he cried, to an officer on board.  “We’ve got to catch a schooner coming down the river—­ the Ellen Rodney.  Do you know her?”

“I’ve seen her,” was the answer, from the tug officer.

“The fellows on board the schooner are kidnapping the father of these boys.  I reckon it’s a serious case—­ a money affair,” he added, in a lower tone.

“Who is the man?”

“Anderson Rover is his name.  If you find him, and the boys make a charge, place all hands under arrest.”

“I will.”

The steam tug was fully manned, carrying a crew and several police officers.  The Rover boys were told to get aboard, and the tug was headed out into the Hudson, or, as here called, the North, River.

“You don’t suppose they have passed here. do you?” questioned the captain of the tug.

“I don’t think so—­ unless that towing tug was an extra fast one,” answered Dick.

“They wouldn’t dare to run too fast, with so many ferryboats crossing the river.  It would be too dangerous.”

The police tug swept out into the bay and then started slowly up the river, moving from one shore to the other.  The police officer in charge had a pair of glasses and he used these on the various craft that came into view, and also allowed the boys to use them.

“Ought to be along soon,” said Tom, after a quarter of an hour had passed.  “It took us quite some time to get down here, you know.”

“Maybe they didn’t come down the river,” suggested the officer.

“Didn’t come down?” cried Sam.  “What do you mean?”

“Maybe they thought you would come down here and wait for them and so changed their plans and went up the river instead.”

“That’s so!” exclaimed Tom.  “They might do that.”

“Well, if they went up the river, we ought to be able to catch them sooner or later,” put in Dick.

“Let us hope so,” returned the officer.

Soon they had passed up the river to a point opposite the Twenty-third Street ferries.  Here a number of boats were moving up and down the stream, and from the Hoboken shore a big trans-Atlantic steamer was coming out, to start on its trip across the ocean.