It needed but a glance about the place to show that only some odds and ends of furniture was all that it contained.

“Where does this door lead to,” asked Mr. Whitford, when he had made a tour of the place.

“Nowhere.  Oh, that is only down into the cellar.” was the reply.  “There is nothing there.”

“We can’t take anything for granted,” went on the agent with a smile.  “I’ll take a look down there.”

He descended with some of his men.  Tom and Ned remained in the kitchen of the cottage, while Andy and his father conversed in low tones, occasionally casting glances at our heroes.  Once Tom thought Mr. Foger looked apprehensively toward the door, through which the custom men had descended.  He also appeared to be anxiously listening.

But when Mr. Whitford came back, with a disappointed look on his face, and said there was nothing to be found, Mr. Foger smiled: 

“What did I tell you?” he asked triumphantly.

“Never mind,” was the retort of Uncle Sam’s man.  “We are not through with Shopton yet.”

“I’m sorry we gave you so much trouble on a false clew,” said Tom, as he and Ned left the Foger premises with Mr. Whitford, the other deputies following.

“That’s all right, Tom.  We have to follow many false clews.  I’m much obliged to you.  Either we were on the wrong track, or the Fogers are more clever than I gave them credit for.  But I am not done yet.  I have something to propose to you.  It has come to me in the last few minutes.  I saw you in your airship once, and I know you know how to manage such craft.  Now there is no question in my mind but what the smugglers are using airships.  Tom, will you undertake a mission for Uncle Sam?”

“What do you mean?”

“I mean will you go to the border, in your airship, and try to catch the smugglers?  I can promise you a big reward, and much fame if we catch them.  An airship is just what is needed.  You are the one to do it.  Will you?”

CHAPTER VII

A SEARCHLIGHT IS NEEDED

For a few moments after the custom officer had made his appeal, Tom Swift did not reply.  His thoughts were busy with many things.  Somehow, it seemed of late, there had been many demands on him, demands that had been hard and trying.

In the past he had not hesitated, but in those cases friendship, as well as a desire for adventures, had urged him.  Now he thought he had had his fill of adventures.

“Well?” asked Mr. Whitford, gently.  “What’s your answer, Tom?  Don’t you think this is a sort of duty-call to you?”

“A duty-call?” repeated the young inventor.

“Yes.  Of course I realize that it isn’t like a soldier’s call to battle, but Uncle Sam needs you just the same.  When there is a war the soldiers are called on to repel an enemy.  Now the smugglers are just as much an enemy of the United States, in a certain way, as an armed invader would be.”