"Over there, straight to the west," Ned said, pointing from theconning tower of the submarine, "is the coast of China, not far fromseventy-five miles away."

  "And there, to the north," Frank said, "lie the Taya Islands. The bigfellow beyond is Hainan."

  The sun was going down into the Gulf of Tong King like a ball of redfire, and the night was far from cool.

  Jimmie declared he could hear the water hiss as the sun dipped its redrim under the waves. The boy now stood by Ned's side, looking over thewonderful scene.

  "We've been somewhere near here before," he said. "You remember thetime we came over to this side of the world and found a key to atreaty box? Well, we wasn't far from this spot at one time."

  "Right you are," Frank replied. "Only we hope to find something moreimportant than a key now. I hope they've had use for a cell key inconnection with that mix-up at Mare Island Navy Yard."

  "It was rotten to let that fellow get away!" Jimmie declared. "I justknew they would."

  "We were all so astonished at the recovery of Lieutenant Scott," Nedobserved, "that we overlooked a few things we ought to have kept inmind. Wasn't it glorious! Think of Scott coming out of it all right atlast!"

  "Well, he said he was a fixture on the coast until he found the manwho came so near killing him," Frank said, in a moment, "and I hopehe'll make good."

  "Huh," Jimmie interrupted, "if you think that fellow is on the Pacificcoast yet, you've got another think comin'. You remember the Diverleft San Francisco just about the time we did."

  "What has that to do with it?"

  "Most nothin' at all, only he sailed in her."

  "You're a wise little man!"

  "And, what's more, we'll see the Diver come pluggin' along here beforewe get this job done," Jimmie went on. "That Captain Moore and his sonare out for blood."

  "But the Diver will require at least a couple of months to get here,"urged Frank. "We can get away before that time."

  "You don't know what the Moores will do," Ned said. "I rather agreewith Jimmie, that we shall see something of the Diver before we leavethis part of the world."

  "I hope so," Frank said.

  "Well, who's for the bottom of the sea?" demanded Jimmie. "I want tosee what's down there before the Bogy Man gets me."

  "I don't mind going down," Ned said. "Come on, we'll close the tophatch and drop to the bottom, then, if conditions are right, we'llenter the water closet, put on the diving suits, and take a walk onthe floor of the big water."

  "Suppose we all go," suggested Frank.

  "Perhaps it may be well for two to remain aboard in order to help theothers out, if necessary," Ned observed.

  "All right," Frank said. "Catch a fish by the tail and bring him infor supper."

  "To-morrow," Jimmie said, "you can take a run on the riparian rightsan' chase whales."

  "I'll wait and see whether you boys come out alive," laughed Frank."I'm a little leary about mixing with the funny little fishes. Some of'em may bite!"

  After a thoroughly interesting voyage, the boys had at last reachedthe scene of their labors. It was now the 20th of October. The SeaLion had rode securely on the float, and Ned and his companions hadspent most of the time during the journey under the great hood whichcovered the submarine, studying the mechanism and making themselvesthoroughly familiar with the big machine.

  Arriving off the Taya Islands, the float had been submerged by openingthe sluiceways and filling the tanks with water. The Sea Lion behavedadmirably when she came to the surface after cutting away from thecompanion of her voyage.

  As there were no appliances for lifting the big float, she was now atthe bottom of the sea for all time, unless broken away from thewater-filled tanks by divers, in which case the upper works would come tothe surface. It was with feelings of keen regret that the boys saw thegreat barge, as it might well be called, lying, deserted, on the oceanfloor.

  As has been shown by the conversation between the boys in the conningtower, Lieutenant Scott had fully recovered from the effects of thepoisonous fumes he had inhaled in the submarine on the night of Ned'sarrest at South Vallejo. Physicians stated at the time that hisrecovery was due to the fact that the conning tower hatch was openwhen the deadly gas was released. Ned, it was also stated, would havebeen dead in a few moments if the hatch had been closed.

  Search had been made, both by the police and the naval detectives, forthe author of the mischief, but he had not been found. It was believedthat his purpose in reporting the result of his own deviltry to thechief of police was to secure the arrest of the boys on the Sea Lionand make off with her.

  Ned did not say so, when discussing the matter with the officers, buthe was satisfied that the Moores were at the bottom of the trouble.The Captain had resigned, and had been observed lounging about thewharf in New York where the Sea Lion lay, and had, it was afterwardslearned, been seen in San Francisco on the day before the arrival ofLieutenant Scott and the Boy Scouts.

  In reaching this conclusion Ned assigned envy as the prime motive onthe part of the Captain and his son. They had expected to be assignedthe duty of searching the ocean floor for the wreck of the mailsteamer. In their great disappointment nothing was more probable thanthat they had resolved to hamper the efforts of their successfulrivals in every way.

  But there was still another view of the case which might beconsidered. The gold in the hull of the wrecked steamer would becomethe spoil of the first submarine to reach her.

  With the double incentive, greed joined to a thirst for revenge, itwould not be at all strange if the Moores had risked everything intheir efforts to prevent the Sea Lion leaving the Navy Yard on herlong trip. It was Ned's private opinion, too, that the son had beenthe one to sneak into the submarine and attack the Lieutenant with thepoisonous gas.

  Leaving Frank and Jack in the machine room, Ned and Jimmie entered thewater chamber and closed the door, which, however, was provided with aplate glass panel of great thickness, so that light from the otherroom supplied plenty of illumination.

  It was not designed to submerge the Sea Lion until the boys were allready to step out. Four deep-sea suits hung on hooks in the waterchamber, one for each of the boys.

  These suits were not much different from those usually worn by deep-seadivers. They were of seamless rubber composition, braced acrossthe breast with bars of steel in order to offset the great pressure ofthe lower levels and give the lungs plenty of room for expansion.

  The helmets, which fitted on the neck of the suits, were lighter thanthose in ordinary use, but fully as strong. The cords attached to thehelmets were very long, and the air-hose admitted of a range of atleast three hundred feet.

  By the side of each suit lay an electric searchlight of specialconstruction and a long steel pole, shaped something like a crowbar,but very slender and strong. This latter for defense in case attackshould be made by some monster of the deep.

  "Say," Jimmie grinned, slipping on his suit, "these spring suits lookto me like someone to button us up in the back."

  "I don't see where you find buttons," replied Ned.

  "Look here, then!"

  The boy pointed to the screws designed to secure the helmets.

  "You button me up, and I'll button you up," Ned laughed. "We've got tolearn to do such things."

  "I'll catch a shark an' get him to learn how," cried Jimmie. "I wonderhow I would look in this suit walkin' down the Bowery. Gee! I bet theboys would jump out of their skins if they saw me comin'. They'd thinktheir master had come to claim 'em!"

  The boys worked industriously for a time, settling themselves in therather clumsy suits, and then all was ready save putting on the heavyhelmets. Jimmie pointed to a belt about the waist of his suit.

  "What's that for?" he asked, pulling at a hook which was suspendedfrom the steel circlet.

  "That's to hang your searchlight on," was the reply. "There may come atime when you'll want both hands to operate that spike thing you'vegot to carry."

  At last the
helmets were adjusted, the cords and air-hose attached,and then Ned motioned to the boys, watching with grinning eyes throughthe plate glass panel, to turn on the air. The first sensation onreceiving the air was one of exhilaration, but this soon passed off.

  Ned saw, by looking through the immense goggles which Jimmie wore,that the lad was almost bursting with laughter, but he knew that thiseffect would soon pass away. He pushed a button, and signaled to Frankto fill the water tanks.

  As the water chamber filled the boys felt a cold circle rise fromtheir toes to their heads. They felt a sinking motion, and soon themysterious life of the ocean became visible through the outer glassdoor of the water chamber.

  The Sea Lion dropped evenly to the bottom. The supply of air was asperfect as it could well be. When the faint jar told Ned that thesubmarine was at last resting on the bed of the tropical sea hereleased a heavy bar which held the door, pushed it back againstconsiderable pressure, and stepped out.

  Jimmie followed, and Ned stopped long enough to point to the lines asa warning that they should not be allowed to become tangled, andstruck off. It was early in the evening, and there was a moon, almostat the full.

  The depth at that point was not great, scarcely more than sixty feet.The pressure of the water overhead made walking rather difficult, andthe boys were strange to the lines they were drawing after them, butthey made good progress until they came to the end of the air-hose.

  It was not as dark under the waves as might have been expected. Thelight of the sun penetrates, ordinarily, to a depth of not far fromforty feet, and the moon's rays on this night were very strong. It wasnot light enough for the boys to see objects around them, but therewas a soft illumination above their heads not dissimilar to the fainthaze of light which lies over a country landscape situated at no greatdistance from a city bright with electricity.

  By using the searchlights, however, the boys were able to distinguishobjects directly about them. They were on a level plain of pure whitesand. Ages and ages ago this pavement laid so smoothly on the oceanfloor had existed in the form of rocks.

  Through countless years it had faced the assaults of the waves, untilat last, in utter defeat, it had succumbed to the mighty force anddropped in fine grains to the lower levels of the world. It seemed toNed that it had lain there for centuries, with never a storm to pileit into ridges or break its level surface into pits.

  The scene about the boys was indescribably beautiful. The inhabitantsof the sea rivaled the rainbow in brilliancy of coloring. There weremore forms of life in sight than either of the boys had ever imaginedin existence.

  Queer-shaped sea creatures with long tails darted about the rubber-cladfigures, and now and then an inquisitive fish with curious eyespoked its nose against the eye plates, as if intent on discoveringwhat sort of creature it was that carried a sunrise in its head.

  There were monster creatures in sight, too, and Jimmie jabbed at oneof them and brought blood. This brought others, and in a short timethe boys found themselves surrounded by a school of sharks.

  Ned threw himself down on the sandy bottom and motioned to Jimmie todo likewise. This seemed to surprise the sharks, for they nosed aroundfor only a moment longer. Seeing no opportunity of getting under theirprospective dinners, they switched their tails angrily, like a cat ina temper, and swam off about their business, if they had any.

  But Ned had little interest in the sea life about him. At anothertime, and under other conditions, he would have enjoyed the novelty ofthe scene to the fullest, but now he was anxiously watching for someindication of the presence of the wreck of the Cutaria.

  He was as certain as it was possible to be that the Sea Lion haddescended almost at the exact spot where the ill-fated vessel wentdown. The hull should be out there in the sand somewhere, and he lostno time in making his investigations.

  But there was nothing on the smooth surface to show that any vesselhad ever rested there. Away to the north, however, the boy finally sawwhat looked like an elevation.

  His flashlight, however, would not throw its beams to the point ofinterest, and he decided to return to the Sea Lion, rest for theremainder of the night, and shift the submarine in the morning.

  Motioning to his companion, therefore, he turned toward the door tothe water chamber. They had proceeded only a few steps when somethingseemed to pass over their heads.

  It was as if a heavy cloud had drifted over a summer sky, outliningits shape on the fields below for an instant and then passing on.Jimmie caught Ned's arm and pointed upward.

  It was plain that the little fellow had caught sight of something hiscompanion had missed, but of course he could not explain then andthere what it was. Ned hastened his steps, and soon stood at the doorof the water chamber, which had been left open.

  As Jimmie pushed into the water-filled apartment by his side and Nedwas about to close the door and expel the water from the chamber, aswell as from the tanks of the submarine, something which flashed likepolished steel hurtled through the water and struck the bottom justoutside the doorway.

  Ned stepped out and picked it up. It was a keen-edge knife, such assailors carry. On the handle was a single initial--"D."

  Ned knew what that meant. Through some strange agency, by means ofsome unaccountable assistance, the Diver had reached the scene of theproposed operations of the Sea Lion.

  From this time on, it would be a battle of wits--perhaps worse!

  CHAPTER VII

  THE SECRET OF THE HOLD