“We can make about three miles to his one,” Jack explained.  “We’re about three hours behind him so we ought to catch him in about an hour or so from now unless he steers a course different from that taken by other vessels.  He’s heading for the Dry Tortugas.”

“Shall we boost the engines a little?” urged Tom.

“No; better let them go as they are,” replied Jack.  “Every machine has what I’d call an ‘economy notch.’  Beyond that on either side more work may be done, or less, but at the expense of straining the engines or fuel or something.  They’re doing excellent work right now, so let’s not disturb them.  It won’t be long now.”

The minutes seemed to drag like hours, however, to the boys.  The glasses were constantly used by Tom, who was perched on top of the pilot house, sweeping the water for a trace of a sail.

“I see her,” he shouted.  “I mean Ship Ahoy.  No, Sail Ho.”

Directly the Fortuna overhauled the vessel they pursued.

“I want to speak to your captain,” hailed Jack.

“Keep off, or I’ll shoot,” replied the mate at the rail.

“Bob, Bob White,” came a whistle from the rigging.

CHAPTER XX

RESCUED AT SEA

“Bob, Bob White,” replied Frank from the Fortuna.  “Oh, there you are, Charley.  Thank God.  Oh, come down and come aboard.”

“Yes, he’ll come aboard,” vociferated the mate in a coarse voice.  He was a brutal looking fellow, to whom the boys instantly took a violent dislike.  “He’ll stay where he is and so will you.”

With these words he drew from the pocket of his trousers a revolver of old style, but of aspect fully as vicious as its owner.  It was of large calibre, and from the way in which the mate handled it he was evidently familiar with its use.

But Jack was not to be daunted so easily.  Stretching the truth a bit, perhaps, he replied to the threat of the mate: 

“Oh, well, if you feel like bucking the government, go ahead.  I can’t sink you with this craft, or you’d be at the bottom in a jiffy.  But you know what it means to disobey orders of an officer.”

At this the fellow perceptibly weakened.  But because the members of the crew had overheard his threats and feeling like so many cowardly bullies do that he must make good his word, even though in the wrong, he again shook the menacing revolver and shouted: 

“You fellows keep off or I’ll shoot.  You can’t steal my crew.  I’m a bucko mate, I am.  You better sheer off.”

“Drop that gun, you villain!” cried Charley Burnett, high up in the schooner’s rigging.  At his words the mate turned.

Instantly a ringing voice from the Fortuna called out: 

“Now I’ve got the drop on you!  Let that gun go and tell the captain I want to talk to him or I’ll have to shoot.”

Tom was perched on top of the Fortuna’s pilot house with a rifle in his hands, the muzzle pointed straight at the mate.