“Now all we have to do is to wait and watch,” remarked Tom, as he came hack from a last inspection of the apparatus in the motor room.

“And that is sometimes the hardest kind of work,” said Mr. Whitford.  “Many a time I have been watching for smugglers for days and nights at a stretch, and it was very wearying.  When I got through, and caught my man, I was more tired than if I had traveled hundreds of miles.  Just sitting around, and waiting is tiresome work.”

The others agreed with him, and then the custom officer told many stories of his experiences, of the odd places smugglers would hit upon to conceal the contrabrand goods, and of fights he had taken part in.

“Diamonds and jewels, from their smallness, and from the great value, and the high duty on them when brought into the United States, form the chief articles of the high class smugglers,” he said.  “In fact the ones we are after have been doing more in diamonds than anything else, though they have, of late, brought much valuable hand-made lace.  That can be bought comparatively cheap abroad, and if they can evade paying Uncle Sam the duty on it, they can sell it in the United States at a large profit.”

“But the government has received so many complaints from legitimate dealers, who can not stand this unfair competition, that we have been ordered to get the smugglers at any cost.”

“They are sharp rascals,” commented Mr. Damon.  “They seem to be making more efforts since Tom Swift got on their trail.”

“But, just the same, they are afraid of him, and his searchlight,” declared Mr. Whitford.  “I guess they fancied that when they took to airships to get goods across the border that they would not be disturbed.  But two can play at that game.”

The talk became general, with pauses now and then while Tom swept the sky with the great searchlight, the others straining their eyes for a sight of the smugglers’ airships.  But they saw nothing.

The young inventor had just paid a visit to the pilot house, to see that his wheels and guiding levers were all right, and was walking back toward the stern of the ship, when he heard a noise there, and the fall of a heavy body.

“Who’s that?” he cried sharply.  “Is that you, Koku?”

A grunt was the only answer, and, as Tom called the giant’s name the big man came out.

“What you want, Mr. Tom?” he asked.

“I thought you were at the stern,” spoke Tom.  “Someone is there.  Ned, throw the light on the stern!” he called sharply.

In a moment that part of the ship was in a bright glare and there, in the rays of the big lantern, was stretched out Big Foot, the Indian, comfortably sleeping.

“Here!  What are you doing?” demanded Mr. Whitford, giving him a vigorous shake.

“Me sleep!” murmured Big Foot.  “Lemme be!  Me sleep, and take ride to Happy Hunting Grounds in air-bird.  Go ’way!”