The first effect of a sudden and utterly unexpected disaster is, usually, to produce incredulity in its victims. It was so in this case.

“Nonsense,” spoke the professor, more sharply than was his wont, “I guess, after all, I am mistaken; it must be an accident.”

“If so, it’s a remarkable one,” said Nat grimly. “The bolt has been slid into a hasp on the outside.”

“Woof!” ejaculated Mr. Tubbs. “Then we are in the position of the mouse that wandered into a nice snug trap.”

“That’s the way it looks to me,” was Nat’s rejoinder. “What do you make of it, Joe?”

The stout lad had, by this time, joined Nat on the stairway. But their combined efforts failed to budge the door.

“It’s locked sure enough,” replied Joe. “Hush!”

“What’s up?”

“I thought I heard a sound of whispering on the outside.”

“So did I. That means there is some one out there listening to see how we are taking it. Let’s give the door a good pounding. Maybe we can make them give some explanation.”

The idea was voted a good one. The two lads shook and banged on the door with all the vigor they possessed.

They were rewarded by hearing a gruff voice growl out:

“Ain’t a bit of use your shaking that door. It’ll hold till we get good and ready to open it.”

“That’s Captain Lawless,” declared the professor.

He raised his voice.

“What do you mean by this outrage?” he loudly demanded.

“Now, perfusser, don’t get hot in the collar,” was the rough advice hurled back at him. “I knows what I’m doin’. You don’t think that I’m goin’ to stand trial before a maritime court just on your account, do you?”

“You precious rascal!” hailed Mr. Tubbs. “I’d like to have my hands on you for about five minutes.”

No rejoinder came this time. Evidently the skipper was not in a mood to bandy words. As a matter of fact, he was half beginning to regret his action in imprisoning the adventurers. To use the vernacular, he was rather apprehensive that he had “bitten off more than he could chew.”

“We’ve got to get out of this somehow.”

It was fifteen minutes later, after an interval devoted to a discussion of their situation, that the professor spoke.

“Agreed,” struck in Mr. Tubbs, “but how in the name of the immortal Abe Lincoln are we going to do it?”

“I’ve got an idea,” said Nat suddenly. “See that old lounge in the corner there?”

They nodded and waited for his next words.

“It’s old and rickety, but it’s made of stout timbers. What’s the matter with using that for a battering ram?”

“Excellent!” exclaimed the professor, catching his meaning. “But what are we going to do if we get out of here?”

“That’s a logical inquiry,” said Mr. Tubbs. “We haven’t got any weapons, and those rascals may be well armed. I know that the captain and the mate always carry revolvers. I’m not sure about the others, though.”

“Humph!” murmured Nat. “I hadn’t thought of that. Tell you what we can do, though. Let’s make a search of the cabin. Maybe we can find some pistols or other weapons in one of them.”

“A good idea,” agreed the professor; “we’ll start by examining the captain’s boudoir.”

They had hardly commenced their search of that worthy’s room, before a shout from Joe announced that he had made a discovery. It was nothing more nor less than a pistol in a case. On the wall, too, apparently as an ornament, hung an aged and rusty looking blunderbuss.

“Hurray!” cried Nat; “that’s something, anyhow. Professor, you take the pistol and I’ll——”

“If it’s all the same to you,” interrupted the man of science, “I had a good deal rather you boys took the weapons. I am short-sighted, and I know that my friend Tubbs is not over familiar with firearms——”

“Except in a shooting gallery at Coney Island,” put in Mr. Tubbs apologetically.

“Very well, sir,” said Nat. “Joe will take the blunderbuss and I’ll carry the pistol. Wonder if that old blunderbore is loaded, anyhow?”

“I’ve got an idea for testing it,” said Joe.

“What’s that?”

“Look here, why wouldn’t it be a good idea to place the muzzle of this ferocious weapon to the door at the point where we think the lock is located? If it is loaded, it’s pretty sure to have enough slugs in it to carry away the lock, and the rest we’ll have to chance to luck.”

“That’s a good suggestion, too. At any rate, it won’t do any harm to try it. We can’t be worse off, unless that rascally captain makes us walk the plank or something, and he wouldn’t dare to do that, I guess.”

“Let’s see if there aren’t some more shooting-irons lying round loose,” suggested Mr. Tubbs; “seems to me that mate always had some in his room.”

But a visit to the mate’s room resulted in the discovery of nothing more formidable than a pair of ancient cutlasses, hung crosswise on the wall. The professor and Mr. Tubbs helped themselves to these, the latter flourishing his in a truly awe-inspiring manner.

“How do you like the weapon?” asked Nat, who, despite the seriousness of their position, could not forbear smiling at the moving-picture man’s antics.

“Man alive!” rejoined Mr. Tubbs, “I only wish that it was possible to get a moving picture of ourselves going into action.”

“Now then, Joe,” said Nat, when they had scoured the cabin unsuccessfully for any more weapons, “it’s time for you to try your stunt.”

Joe ascended the stairs and carefully placed the muzzle of the blunderbuss in position under the spot where he was certain the lock was situated.

“All ready?” asked Nat in a strained whisper.

“All right here,” responded Joe, his finger crooking on the rusty trigger.

“Then let her go!” came the command.

But before Joe could press the bit of steel which he hoped would discharge the gun, there came a startling interruption.

Bang!

Another gun had been fired outside. What could it mean?

“That’s the Nomad’s gun. They are attacking her and trying to make Ding-dong a prisoner!” cried Nat.

Bo-o-o-o-o-m!

The rusty throat of the old blunderbuss roared, and Joe was knocked clean off his feet by the accompanying “kick.”

At the same instant the door was blown into fragments, and a stentorian voice could be heard roaring out:

“Howling tornadoes! What’s that? A volcano?”

“Reckon somebody was taking a siesta on that door and old Mister Blunderbuss disturbed him,” grinned Nat, as he caught Joe in his arms.

“Forward!” yelled Mr. Tubbs, brandishing his cutlass in the manner made familiar by the heroes of naval pictures of the olden time.

The others caught the infection.

“Forward!” cried Nat, and, shoulder to shoulder, they plunged up the companionway, burst through the shattered doorway, and rushed pell-mell out upon the deck of the schooner.