Left alone in the Sea Lion, Jimmie spent most of his time watchingfrom a darkened window. He could distinguish little in the faintsifting of moonlight which dropped down from the sparkling surface ofthe sea, but there was companionship even in that.
He had been instructed by Ned to keep the interior dark, and so hewatched the ocean floor for the lights which his chums might beobliged to turn on. As the reader knows, however, the exploring partyshowed no lights at all until the interior of the wreck had beengained.
Listening and waiting, half inclined to admit that he was just alittle bit lonesome, the boy stood at his post for about a quarter ofan hour. Then he saw an opaque object moving toward the submarine.
It was not a shark or other monster of the sea, for it walked uprightand seemed to move up and down as it came to the little undulations inthe ocean floor. When it came nearer Jimmie moved toward the door ofthe water chamber.
"That must be Ned," he thought, "comin' back alone. Now, I wonder ifanythin' has happened to Frank an' Jack?"
For a moment the heart of the lad throbbed wildly, then he calmedhimself with the thought that in case of accident he would have beennotified by the lifting lines. The air machine was working perfectly,too, and this indicated that all was well below.
Finally the moving object came to a position about ten yards distantfrom the submarine and stopped. He was now about fifty feet below thewindow out of which Jimmie looked, for the Sea Lion, as has been said,lay well up from the bottom, not exactly over the wreck but not farfrom it.
In a moment the boy saw the glimmer of a lamp down where the man was,and saw that it was moving about on the bottom. Lights, of course, donot show in water as they do in air, and so it was only a faintillumination that Jimmie observed.
Still, he could see that whoever was carrying the light was fumblingabout on the bottom. He watched intently for a moment and then saw theman coming toward him, swimming straight up.
"I guess it's one of the boys," Jimmie mused. "He must have lost hisline, and when I saw him fumbling he must have been removing theweights designed to hold him down in spite of the air in the helmet."
This appeared to be a good explanation, and the boy stood with hisface pressed against the glass panel of the water chamber door,waiting for whoever it was to enter, close the apartment, and push thelever that controlled the exhaust which emptied the chamber.
At last the swimmer clambered into the chamber, and the waiting boywas about to switch on a light when a suspicious action on the part ofthe other caused him to hesitate. He could observe the actions of theman in the water on the other side of the glass panel quite clearlynow, and was alarmed at what he saw him doing.
Instead of drawing his air-hose in with him and coiling it carefullyso as to clear the doorway and still leave free passage for the airwhich was being pumped into it, he laid the hose carefully in aslide-covered groove in the edge of the door. The hose did not seem tobe quite large enough to fill the groove, and the fellow took somethingsoft and pliable from a pocket and wrapped around it.
Then he closed the door and pushed the lever which released the powerthat forced the water out of the chamber. Only one inference was to bedrawn from the scene which Jimmie had witnessed.
The man in the water chamber was a stranger. This was merely anattempt to get possession of the Sea Lion.
The fellow was breathing air pumped into his hose by some other boatthan the Sea Lion. He had cast off his weights in order to gain thechamber, which neither one of the boys would have found necessary, asthey would have been carried up by the machinery which worked thelifting and descending lines.
Another thing the boy realized, as he waited with anxiety for the nextmove. The man, whoever he was, was thoroughly familiar with the planof the Sea Lion.
The grooves in the edge of the door had been planned so as to giveentrance to visitors who were not receiving their air from the SeaLion. No one was believed to know anything about this arrangement--noone save the builders and the Secret Service men.
While Jimmie watched, the intruder moved the lever and the water inthe chamber began to lower. When the water was forced out fresh airwas automatically forced in.
Before long the intruder disconnected his hose with his helmet andthrew the end over a hook provided for that purpose. When the waterwas all out he knocked heavily on the door leading to the room whereJimmie stood.
"There'll be doings here directly," the boy thought.
Again and again the visitor beat upon the door, but Jimmie gave nosign. He could not well observe the man now, for, with the water outof the chamber, the light carried by the man inside shone brightlyagainst the glass panel, and the boy would have been observed had hestood close to it.
Jimmie grew more anxious as the seconds passed. He was trying to putaway the thought that the intruder had cut the air-hose attached tothe helmets of his friends.
For all he knew all three boys might be lying drowned, on the floor ofthe ocean. The thought was unbearable, and he resolved to banish it inaction.
His first impulse was to disconnect the exhaust and fill the chamberwith water. The man in there had disconnected his air-hose and wouldsoon drown.
But the brutality of such a course soon presented itself, and Jimmiecast about for some other method of meeting the dangerous situation.He could hear the visitor fumbling at the door, and wondered if heknew the secret of opening it.
After a time it seemed to the listening boy that the fellow wasfeeling in the right locality for the hidden spring which would openthe door from the other side, and sprang for the bar which secured itagainst such entrance. Then he dropped the bar and stood wiping thesweat from his forehead.
"If I bar the door," he mused, "that robber will cut the air-hoseprotecting the boys outside, if he has not already done so. I've justgot to let him in here an' take chances."
He hastened to the back of the room and brought a long coil of rope.Making a running noose in one end, he released several loops from thebig coil and held them loosely in his hand.
"I wonder if I can assist him into our princely apartments?" thoughtthe boy, whimsically. "If I can get this rope around his body and overhis arms, I'll be the boss of the precinct! I expect he'll tumblearound a good deal, but I guess I can quell him!"
The boy waited in the darkness until a faint click told him that theintruder had discovered the spring. This was followed by a slam as thesliding door fell back.
Then all was still. Jimmie, hidden in the shadows, prepared to throwhis lasso as soon as the visitor left the doorway.
"Hello!"
The voice carried a hoarse challenge.
"Any one here?"
The man was still in the doorway, and was swinging his light about soas to give him a better view of the room.
"If he would only drop his arms!" Jimmie mused. "I'd like to hit himwith a ballclub!"
Directly the fellow did drop his arms, and at the same moment steppedout of the shelter of the doorway. This was what Jimmie had beenwaiting for, and he lost no time in acting.
The rope cut the air and descended over the intruder's head and arms.The lad's hours of practice while playing cowboy now proved to be ofgreat worth.
Jimmie gave a quick jerk as the rope landed and he ran to the back ofthe room. He heard the other fall, and knew by the weight that he wasdragging him.
When he gained the wall he switched on the light and reached to ashelf for a weapon. When he faced his captive he held an automaticrevolver in his hand.
By this time a torrent of expletives was coming through the helmetopening where the air-hose had entered. The prisoner rolled about onthe floor, trying to get to his feet.
"Whoo-pee!" shouted the boy. "Look what one can catch out of theocean!"
A roar of rage was the only answer.
"Take off that helmet!" commanded the boy.
A muffled challenge came from the interior.
"All right," said the boy, "then I'll take it off for you. But I'llhave
this gun handy, and if you try any foolishness you won't holdwater when I get done shootin'."
Before long the helmet was off, and Jimmie was looking into as evil aface as he had ever seen. It was the face of a stranger, and yet thereseemed something familiar about it.
"What sort of a game is this?" demanded the captive. "If you knowwhat's good for you, you'll quit this cowboy business."
"Who are you?" asked Jimmie.
A snarl was the only reply. The enraged man was tugging fiercely atthe rope.
"Quit it!" warned Jimmie. "I'll have to put you to sleep if you trythat."
"You don't dare!"
"Don't four-flush!" the boy advised.
"Release me!"
Jimmie sat down and leveled the weapon at the struggling man.
"I guess I'd better shoot," he said, calmly. "I suppose you've cut theboys' air-hose, and I'll have to get back to New York the best way Ican--alone. So, you see, I can't be bothered with you."
The captive ceased his struggles and managed to rise to a sittingposition. His eyes were not so threatening as before.
"No," he declared, "I didn't cut the hose."
"Why? You're equal to such a trick."
"I was told not to."
Jimmie hesitated a moment. He wished devoutly that he could believewhat the fellow said.
"Who told you not to?" he then asked.
The captive shook his head.
"I don't know his name," he said.
"And you are sailing with him?"
"All I know is that he is called the Captain."
"I see," said the boy. "Now, how comes it that you know so much of theplans of the Sea Lion?"
"What makes you think I do?"
"You found the groove in the door, and also the spring that opens thedoor to the water chamber."
"Oh, that!"
"Well?" the boy flourished his weapon, though nothing could haveinduced him to fire on the unarmed man.
"I was told what to do when I got here," was the reply.
"Did you see my chums on the way here?" The captive nodded.
"Where?"
"At the wreck."
"Where is your boat?" was the next question.
"On the other side of the wreck."
"And you are after the gold?"
"Of course."
"And important papers?"
"I know nothing about that."
"What is the name of your boat?"
"The Shark."
"Appropriate name that!" laughed Jimmie. "Used to be the Diver, didn'tshe?"
"I don't know."
"What did you come here for?"
"To get the boat."
"And remove it?"
"Of course."
"That would have meant death to the boys who are out in the water atthis time?"
"I suppose so. Say, there's something wrong with your air machine. Iknow something about such contrivances, and this one acts as if a hoseout in the sea had been cut!"
CHAPTER X
A CHASE ON THE OCEAN FLOOR