“Lots.  I’m going to keep a watch on that stateroom until I get a good look at the people in it.  And if they only come out at night, which it begins to look like, I’m going to do some night watching.  This thing has got to be settled, Ned.  Our trip to the city of gold is too important to risk having a mysterious couple on our trail—­ when that same couple may be the Fogers.  I’m going to do some detective work, Ned!”

CHAPTER XI

THE MIDNIGHT ALARM

“Whew!  What a lot of ’em!”

“Bless my fish line!  It’s a big school!”

“Look how they turn over and over, and leap from the water.”

“By golly, dere is suttinly some fish dere!”

These were the exclamations made by our four friends a few days later, as they leaned over the rail of the Maderia and watched a big school of porpoises gamboling about in the warm waters of the gulf stream.  It was the second porpoise school the ship had come up with on the voyage, and this was a much larger one than the first, so that the passengers crowded up to see the somewhat novel sight.

“If they were only good eating now, we might try for a few,” observed Ned.

“Some folks eat them, but they’re too oily for me,” observed a gentleman who had struck up an acquaintance with the boys and Mr. Damon.  “Their skin makes excellent shoe laces though, their oil is used for delicate machinery—­especially some that comes from around the head, at least so I have heard.”

“Wow!  Did you see that?” cried Tom, as one large porpoise leaped clear of the water, turned over several times and fell back with a loud splash.  “That was the biggest leap yet.”

“And there goes another,” added Ned.

“Say, this ought to bring those two mysterious passengers out of their room,” observed Tom to his chum in a low voice.  “Nearly everyone else seems to be on deck.”

“You haven’t been able to catch a glimpse of them; eh Tom?”

“Not a peak.  I stayed up several nights, as you know, and paced the deck, but they didn’t stir out.  Or, if they did, it must have been toward morning after I turned in.  I can’t understand it.  They must be either criminals, afraid of being seen, or they are the Fogers, and they know we’re on to their game.”

“It looks as if it might be one or the other, Tom.  But if they are criminals we don’t have to worry about ’em.  They don’t concern us.”

“No, that’s right.  Split mackerel!  Look at that fellow jump.  He’s got ’em all beat!” and Tom excitedly, pointed at the porpoises, the whole school of which was swimming but a short distance from the steamer.

“Yes, a lot of them are jumping now.  I wonder—­”

“Look!  Look!” cried the man who had been talking to Mr. Damon.  “Something out of the ordinary is going on among those porpoises.  I never saw them leap out of the water like that before.”