“Do you know their names?”

“No, I can’t say I do, though it seems as if I’d heard one of them called Fred. I can’t say which it was.”

“Do they always come by on the same day—­on Wednesday?” asked Jane, forgetful once more of Dean’s warning to let him do the talking lest her voice should betray her sex.

“Come to think of it,” said the man, apparently noticing nothing unusual, “I guess it always is on a Wednesday they come by.”

“Is the number of their car anything like this?” asked Dean, exhibiting an entry in his notebook.

“I couldn’t say,” said the man, studying the figures.  “I know it is a New York license, and the number ends with two nines like this one does.  What might you be wanting them for?”

He spoke to a cloud of dust, for Dean had started up the motorcycle before he finished speaking and already was speeding away.

“Where now?” asked Jane.

“I don’t know,” he answered frankly, “I only know we are going the direction the Hoffs went, and I want to gain on them before they get too far ahead.  The chap back there had told us all he knew and was beginning to get curious, so I thought it better to vamoose.”

“It’s funny about his never seeing them coming back.”

“Probably there is nothing mysterious about that.  I have a notion they always come up one side the river and down the other, taking the 125th Street ferry home.  That would not be a bad plan to help them in eluding too curious observers.  All these German spies are trained to leave as blind a trail behind them as possible.  The thing we have got to discover is what brought them up here.  We’ve just got to find out their destination.”

“I am afraid there is little chance of our doing that,” insisted Jane.  “We’ve nothing to go on.”

“We’ve learned something.  We know that their destination is somewhere between here and Fort Lee on this side of the river.  That narrows down the search considerably.  That’s more, too, than anybody else that the Chief has had on their trail has learned.  Something tells me that we are getting warm right now.  Obviously the place they come to must be nearer West Point than it is New York.  They would hardly take too roundabout a course, even for the sake of hiding their tracks.  Keep a sharp lookout for tire tracks leaving the main road.”

The route they were following quickly led them into a sparsely inhabited mountainous district and instead of the concreted state highway they found themselves on a hilly dirt road, full of ruts and loose stones that made travel difficult.  At times it was all Dean could do to manage the machine, so that he had to leave most of the task of observing the by-ways to Jane.  For more than two miles they had seen neither house nor barn.  Once or twice they came upon little used lanes leading off through the woods, but none of them showed any traces of the recent passing of an automobile.