“He is certainly up to something out of the ordinary,” thought Sam.  “I wonder if he is fishing?  If he is, it seems to me it is a queer way to go at it.”

As Wingate left the rail he walked directly to where the boy stood.  When he discovered Sam he started back as if confronted by a ghost.

“Oh—­er—­didn’t know anybody was up,” he stammered.

“It was so hot in my stateroom I couldn’t sleep,” answered Sam.  “I came out to get the air.”

“It’s almost as hot on deck as it is anywhere,” said the deck hand, and his tone had little of cordiality in it.

“I think I’ll go forward and try it there.”

“Yes, it’s a little breezier at the bow, sir.  By the way, did you—­ er—­see me trying to catch some of those firefish just now?”

“I saw you doing something, I didn’t see what.”

“I thought I might get one, but they are all gone now,” answered Wingate, and slouched off, whistling in that peculiar manner of his.

Sam walked slowly to the bow.  As he did this, Wingate turned to look at him in a speculative way.

“Wonder if the young fool saw what I was up to?” he muttered.  “If he did I’d better go slow.  I don’t want to get caught.  They might treat me pretty roughly.”

The watch on deck was changed and Wingate went below.  Asa Carey was in command of the yacht and he, too, wanted to know why Sam was up at such a late hour.  The boy told him, but said nothing to the mate of Wingate’s strange actions.

When Sam turned in, Dick wanted to know if he was sick.

“No, only restless, Dick,” he replied.  “By the way, I saw something strange,” he continued, and he related the occurrence.

“We must look into this, Sam.  It may mean nothing and it may mean a great deal,” was the eldest Rover boy’s comment.

The boys did not go on deck until after breakfast.  Then they walked to the starboard rail and stopped at the spot where Sam had first discovered the deck hand.

“I don’t see anything,” said Dick, gazing over the rail.  “Perhaps he was fishing, after all.  He may have thought—­Hullo!”

“What is it, Dick?”

“Some kind of a line down here—­a wire, fastened to a hook!”

“Can you reach it?”

“Hardly.  I might if you’ll hold my legs, so I don’t go overboard.”

“Hadn’t we better tell Captain Barforth of this first?  The wire may belong there.”

“I don’t know what for.  But we can tell the captain.  Here he comes now.”

“Good morning, boys,” said the master of the steam yacht pleasantly.  “What can you see over there?”

“Something we think unusual,” said Sam “Please take a look and tell us what it is.”

Captain Barforth did as requested.

“That wire has no business there,” he declared.  “I don’t know how it came there.”

“I can tell you how it got there, and I guess you’ll find something like it on the other side,” answered Sam, and told what he had seen Wingate do during the night.