It was a shrill whistle, twice repeated, and it came from the same direction in which the two men had gone a short time before.

Undoubtedly it was a signal denoting urgent need of haste. The actions of the tall smuggler would indicate as much; for he dashed out of the cabin like a shot, and Jack heard the thud as he threw the shovel into the shrubbery surrounding the lone hut.

Then followed the crashing of bushes as the man started by a circuitous route toward the upper end of the island. He must know every foot of the ground, and by taking to the open beach, could gain a given point much sooner than one who kept to the thick undergrowth.

Jack saw the lantern had been hastily dropped, though it was still burning. He was trembling with excitement, and feeling very much as though he wanted to yell at the top of his voice as he picked up this abandoned tool of the discovered smugglers.

He could hear the boys talking down there where the trio of motor boats were anch.o.r.ed; and could imagine how they must be wondering what all the racket on the island meant; while Josh would doubtless start in to tell them how he, Jack, had persisted in going ash.o.r.e.

Some one was coming, for Jack could hear quick footsteps near by. He still held his Marlin gun, but was loath to even threaten to use it. Nor was there any need, for a moment later the moving dim figure took form, and proved to be no other than Professor Marshland.

At sight of Jack standing there, lantern in one hand and gun in the other, the gentleman allowed something like a grim smile to creep over his face, even as he came hurrying up, almost out of breath from his exertions.

"Do you know what it all means, Jack?" demanded the other, as soon as he reached the side of the boy.

Jack nodded his head eagerly.

"I was looking in through a crack, and saw what that man did. But I'm sorry he got away from you, sir," he replied.

"I managed to capture the two fellows who left the hut!" the government agent exclaimed. "My Indian has meanwhile overcome the chap who was sent to watch your boats. But unless I can overtake the ring leader of the bunch, I shall feel that my work has not been wholly a success."

"He headed for the upper end of the island," Jack put in.

"Yes, and I have reason to suspect that the other two men are there with the boat. You will be surprised when I tell you that they actually turned pirates and captured the speed launch which you told me belonged to an acquaintance of yours."

"The _Flash_," echoed Jack. "No, I am not surprised, for I had begun to suspect something like that. They must have made Clarence threaten to run us down, hoping we would pull up anchor, and get away. But if that is so, you could never hope to overtake them in that slow little boat of yours."

"Well, I should say not!" declared the other.

"Now, if it were the _Wireless_, for instance, you might have some chance," Jack went on.

"Which is just the point I wanted to put up to you boys," cried the government agent, eagerly. "Would you be willing to a.s.sist me run that clever scoundrel down? Do you think George would care to try conclusions with the _Flash_?"

At that Jack laughed.

"Why, sir," he declared, "he's been just wild for the chance, ever since we first set eyes on that narrow boat. He believes he can beat her out in a race. Suppose you come down with me right now, and we'll ask him."

"Thank you, Jack; it was a lucky day for me when I ran across you boys.

But let us lose no time; for doubtless they'll be off as soon as they can, knowing that the game is now up, and all that remains to them is escape."

Nothing loth, Jack accompanied him as he started along the broad trail leading down to the cove. He could readily understand now that the revenue man must have investigated to some purpose that day while at the cabin; and knowing there were no smuggled goods in the cache then, had laid his plans to come back in the night, in the expectation of catching the rascals in the act; which was just what he had done.

CHAPTER XIX-A RACE IN THE MOONLIGHT

"Hold on!" said the agent abruptly.

A dark figure had risen up before them; and as the moonlight fell upon the man Jack saw that it was in truth the Indian guide who had been with the "professor" in the noisy motor boat.

"Did you get him, Josh?" demanded the employer, eagerly.

"He lies under hemlock, tied hand and foot. No danger he get away," came the confident reply.

"All right," said the other. "Come along with me, John. These boys will guard the cabin and not let any one steal the hidden goods. We have other work cut out for us. We want to get our hands on that head man, Glenwood. So long as he is at large there can be no peace on the border."

Great was the astonishment of the five boys when Jack and his companions made their appearance on the sh.o.r.e, and the former called to have the small boats pushed in, so that they might come aboard.

"Jack, what's all this mean?" asked George, greatly excited.

"Can't tell you everything just now, fellows," the other replied. "This gentleman is a government revenue agent, and he's on the track of a band of smugglers who have been using this island as a place to land goods brought over from Canada. He captured three, but the leader got away.

George, he wants to borrow your boat."

"What?" gasped the other, astounded beyond measure.

"He and his man and myself will go with you, Josh changing over," Jack continued. "While we're gone the rest of you keep on the watch and don't let anybody come aboard, no matter who he is. These scoundrels have captured the _Flash_."

"Now, what d'ye know about that?" exclaimed Nick, as he helped Josh over the side of the big _Comfort_, so as to make room for the others who were to go in the speed boat.

"But George, you haven't said yet whether you are willing to chase the _Flash_, and try to overtake her?" said the energetic agent.

"Sure I am," came the ready response; "and I believe we can get her, if nothing happens to my motor. I've had some hard luck with it when I tried to push the thing to the limit. But tumble in here, and we'll be off."

George was trembling with delightful antic.i.p.ations. If anything in all the world appealed to him it was a race. None of the others had the same feeling, and, like Jack, they preferred comfort in a boat beyond speed, though none were averse to making good time.

Everybody wanted to help, and as many hands make light work, the _Wireless_ was in condition to start almost as soon as the two men climbed aboard.

"Sit as near the middle as you can, please, to balance her," the others heard the skipper say, as she shot away.

"Yes," called out Nick, derisively, "and be sure your hair is parted in the middle, or it's all up with you. I know, because I was there for some four weeks."

"Which way, sir?" asked George, wisely paying no attention to this shout, which, after all, was Nick's only method for getting even, after all the agony he had endured in that cranky narrow motor boat.

"Turn to port, and head for the upper part of the island. We haven't wasted much time, and I hope to discover that boat somewhere," replied the agent.

"If we do," said George, with firmness, "make up your mind the good old _Wireless_ is going to hang on like a bulldog till she cuts down the lead, and overhauls that _Flash_. Always said she had the look of a pirate, and others thought the same thing, it seems, since those men picked her out as the boat they could use."

"Just think of Clarence and Joe being in their hands all this time,"

remarked Jack, as they tore through the water. "Must seem like a pretty tough vacation for those boys, all right."

"Oh! I don't suppose Glenwood has really harmed them," said the agent; "but he's a hard man to deal with; and unless they knuckled down to him perhaps they've felt his fist before now. I'm hoping that, perhaps, when Clarence sees who is after him he may find some way to slow down and let us overhaul him."

George only laughed at this and remarked:

"That's because you don't know Clarence, sir. He hates me like poison, and sooner than have me beat him with my boat I believe he'd take the chances of staying in the power of those smugglers for a month. Oh! no, when he sees who is after him he'll put things at top-notch speed, and try every trick he knows how to win out. But I'm not afraid, if only things go right with my engine."