Jerry collected himself with an effort. It must indeed have been a bitter pill for him to swallow, reflected Mart as he watched the old quartermaster, while Bob stood at his elbow. Jerry had gone down leaving his gang in full possession of the yacht; he had evidently found the wreck untenanted by the Pirate Shark; and he had returned to the surface to find all his fine schemes shattered by the two boys.

Undoubtedly the old man was a villain, and he had showed that morning that he cared nothing for human life so that his plans were carried out; but now he looked so helpless, sitting there in the blazing sun with his white hair falling over his neck, that the boys could not help feeling a touch of sympathy for him.

"Lads," he said slowly, gazing up at them with his gentle blue eyes, "I found that there wreck, and she's split apart so's her cargo can be got at easy. There's gold a-lyin' there for the pickin' up, lads!" His voice grew hoarse with eagerness.

"Eight fathom down she lies, lads, eight fathom down! I got to go down again, lads—I been waitin' too long for this chance! I just want to get my hands on that there gold, I do. The Pirate Shark ain't around, lads—don't be hard on old Jerry! You've got me, lads, you've got me. Don't put me in irons yet, lads. Let me go down once more, just to get my hands on that there gold—"

"Calm down, Jerry," broke in Bob, as the quartermaster's voice grew hoarser still, his old face working almost hysterically. "We're not going to hurt you. I tell you what. Wait till dad gets back with Swanson and the crew, then we'll get up that treasure for you—"

"No!" Jerry's voice rang out clear and strong, a feverish anxiety in his face. "I want to do it myself, lads! If the Pirate Shark's there I want to get at him with that there kris!"

"Where is the kris, by the way?" interjected Mart.

"Stickin' in the side o' the wreck," replied Jerry in a calmer voice. "She's layin' over on her side, hard and fast in the coral. I felt around a bit, lads, and I seen a box there—it's rotten, it is, and it's full o' gold! The mystery o' the sea, lads, the mystery o' the sea! The gold's down below, and us up here above—and fish tell no tales, lads! Let me go down once more, lads, and I'll not say another word, or cause any more trouble, that I won't!"

The boys looked at each other irresolutely. After all, reflected Mart, there could be no risk to themselves in letting Jerry go down again. He was plainly in a high state of excitement at having found the wreck and possibly the treasure, and it would possibly be more injurious to restrain him than it would be to let him continue his work.

Of course, there was danger from the Pirate Shark, and a terrible danger it was. But as Jerry had said, once he stood with his back against the wreck and the kris in his hand, he would be able to hold his own. The great danger came from the chance that the shark might catch him going down or coming up, overturn him in the water, and snap him off.

"I don't know," said Bob slowly. "Of course, if that shark wasn't there—"

"I can take care o' him," broke in Jerry eagerly, clutching at his helmet. "He allus snaps off the lifelines first, they say, lads. If the lines or the hose breaks, why, haul up on whichever's left. But he ain't there, lads, he ain't there! You'll let old Jerry go down again! Come an' help me up, lads."

"Hold on," exclaimed Mart as Bob impulsively started forward. "We don't aim to let you start any rough-house with us, Jerry. I don't trust you a little bit. Bob, you stand by while I help Jerry get his helmet on, then get the pump goin' while I slide him over the edge of the platform."

The quartermaster broke into a flood of eager words, which Bob abruptly cut short.

"Look here, Jerry! What about dad? Are they holdin' him prisoner on shore, like you said, or—or—"

He paused, and Jerry chuckled as he glanced up, his head on one side like that of a bird, his blue eyes suddenly bright again.

"No, no, lad! He's just taken care of, that's all. Mebbe we'll make a compromise yet, lads—you holdin' me and the yacht, and me holdin' your father, eh! Well, we'll see. Birch can get him off, lads. Birch talks the lingo, he does, and if anythin' happens to me, you talk to him."

This speech relieved the minds of both boys immensely. Half their fears had been for the men who had gone so trustingly into the jungle, to be held prisoners by the Malays, and now that they were sure no harm was being done Captain Hollinger, they felt much more inclined to deal gently with old Jerry.

"So when you promised dad that you'd have gold on board when he came back," said Bob with a slow grin, "you meant the treasure, eh?"

Jerry chuckled and nodded.

"Aye, lads, just that. But you'll mind the pumps, eh? You'll not let old Jerry go without air?"

"Sure not," Mart reassured him. "We'll take care of you fine, Jerry."

The quartermaster reached out for his big helmet, and Bob sprang forward to assist him. At the same instant, however, they were startled by a hail from the shore, and looked up to see Birch standing beside the stranded boat.

"Seamew ahoy!" he called again.

"Well, what do you want?" returned Mart.

"Let me row out alone? I want to talk."

Mart glanced at Bob. "How about it, Holly? I s'pose he wants some grub and water."

"Let him come out, lads," spoke up Jerry before Bob could reply. "You've got us, you have; let him come out, lads, and talk it over."

"All right," shouted Mart to the seaman, then turned to Bob. "Holly, you get up on deck with one o' them rifles. If there's any trouble, you shoot Jerry, see?"

Bob grimaced behind the quartermaster's back, and ascended the ladder. Watching the shore, Mart saw Birch turn and say something; the forms of the other men came from among the bushes and they helped shove out the boat. The one-eyed seaman leaped into her and settled down at the oars.

As Jerry was firmly anchored down by his weights and heavy boots, Mart had no fear of any trouble arising. When Birch had come within twenty feet of the yacht, however, Mart stopped him curtly.

"Close enough, there! Now, what do you want?"

"Water, sir," pleaded the seaman respectfully. "You've got us, sir, and you've got Jerry, there; but you ain't goin' to torture us, be you?"

"No," returned Mart. After all, he reflected, the complaint was only just. There was no water on the island, and it would be rank torture to maroon the four men there without either food or drink, for the afternoon sun was at its height.

"You stay where you are, Birch," he went on. "When we've got out a breaker of water and some biscuit, you can come in for them."

Birch nodded, and Mart went up the ladder to where Bob was waiting. Taking the rifle from the hands of his chum, he asked Bob to get out a breaker of water and a bag of biscuit. Bob nodded and darted forward, while Mart remained leaning over the rail, his rifle in plain sight.

Down below, Jerry gazed at Birch solemnly, then shook his head.

"You made a fine mess o' things," he declared slowly. "A fine mess o' things, Birch! The treasure's there, eight fathom down."

"It's your own fault," retorted the other sullenly. "Didn't we say to send them kids ashore, hey? But you wouldn't do it, and now they've got us."

"Yes, they've got us!" screamed old Jerry suddenly, shaking his fist as he sat. "They've got us, you fool! Why didn't you keep your eye on 'em, eh? You're fine mates for a man to have, you are! The minute I gets out o' sight, you have to go and smash up everything! Nice set o' mates, you are. Bah!"

And the disgusted quartermaster spat into the water, while Mart grinned in enjoyment of the scene. Jerry's vehement anger was certainly unfeigned, while Birch grew more sullen with each moment. Verily evil-faced and villainous he looked, as he sat in the blazing sun and leaned on his oars, and Mart shuddered to think what might have happened to all of them had it not been for that elephant gun.

At this juncture Bob arrived with a small keg of water, which he carried down to the landing. Then he went forward again after a bag of biscuit. As the terrified Ah Sing was still burning joss sticks and chattering prayers to his ancestors, Bob had to rummage about for the biscuit himself, but he finally secured a half-emptied bag, which he carried down and deposited on the landing below.

"Come along, Birch, and don't try any funny work," demanded Mart. "Bob, you sling 'em into the boat and keep out of his reach."

But Birch had plainly come without any thoughts of treachery. He rowed up slowly until the prow of his boat scraped the landing, and Bob heaved the keg and biscuit aboard, shoving off the boat instantly. Without a word, Birch sullenly fell to work at his oars again and headed for the island. Mart set down the rifle and descended to the landing.

"Well, if you'll give me a hand wi' this here helmet, lads," suggested Jerry, "I'll be goin' down."

Bob stepped forward and helped him on with the big helmet, screwing it down into the collar. Mart stood over the pump wheel, and as he glanced at the island he saw that Birch had landed, and that he and the others were carrying up the water and biscuit. It occurred to him that before dark he must make sure that the boat was shoved out, even if he had to go ashore in another boat to get it; for it was imperative that the four mutineers should be unable to leave the island.

However, there was plenty of time left for that, he thought, and so turned to Jerry. Bob was just completing his task, and Jerry had opened the front window of his helmet for a parting injunction.

"You'll mind the pumps, lads?"

"You bet!" replied Bob cheerfully.

"Hold on," cried Mart quickly, as the quartermaster began to close his window. "You sure you've got that kris handy down there, Jerry? You don't want to take any chances, you know."

"It's there, lad, it's there, eight fathom down," responded Jerry with a faint chuckle. "It's a-sticking into the old wreck, it is, right where I can put my hand up to it. Well, lads, mind them pumps now! Good-bye, lads—here's to the mystery o' the sea, and hoping as the Pirate Shark ain't around!"

So Jerry collectedly shut himself in and waited until Mart, at the pumps, had got his diving suit well inflated. Then, disdaining Bob's proffered assistance, he worked himself to the edge of the landing and slowly lowered himself over into the water. Bob seized the lines and paid them out slowly, thus holding Jerry upright and keeping his descent slow and steady, while Mart pumped slowly and methodically, alternately watching the flickering helmet down in the green depths and the pump-gauges.

At length the gauges marked seven fathoms, and the dial finger slowly rose to eight, then stopped suddenly. Jerry had reached the bottom.

"All right, Holly," said Mart quickly. "Come along an' take the other wheel."

Bob dropped the lines in a heap and sprang to the pumps. For a moment the two boys worked in silence, then Mart chuckled.

"Say, I guess we've got those pirates scared stiff, eh?"

"Looks like it," returned Bob, his eyes on the water. "That fellow Birch—great Scott! Look there!"

The sudden fear in his voice struck Mart like a blow. Looking at the water, he saw a little line of bubbles rising, and the terrible significance of it sent horror into his heart.

"The hose is cut!" he cried, and leaped to the lines.

But though he tugged, there came no answering pull. White-faced and stricken by the swift terror of what had happened, he began yanking at the line and hose together, and as they came swiftly up he felt a thrill of cold dread that seized on his heart and held him dumb.

With feverish haste he hauled in both lines, shrinking at thought of what had befallen the old quartermaster. Then, without warning, the lines shot up and curled about the landing—cut short and clean.

"The shark—" began Bob, white-lipped and paralyzed with horror.

"No!" exclaimed Mart, his mind leaping ahead swiftly. "The kris, Holly! He said it was stickin' in the wreck. The lines came against it and cut off! Here, get the other lines connected up with that spare helmet—move lively!"

Bob stumbled forward in blind obedience, as Mart flung away the useless lines and darted to the spare diving suit, which lay ready with its hose and lines coiled at its side. He opened the wide neck and, snatching off his shoes, began to get into the huge garment in feverish haste.

"What you going to do?" queried the doubly horrified Bob.

"Goin' down, o' course," snapped Mart. "Hurry up, there!"