The news that old Captain Jules Fontaine, the retired pearl diver, whose history was a mystery to most of the inhabitants at Cape May, was to take Madge Morton down to the bottom of Delaware Bay with him spread through the town and seaside resort like wildfire. It was in vain that the houseboat party and Captain Jules tried to keep the affair a secret. There were necessary arrangements to be made, men to be engaged to assist in the diving operations; it was impossible to deny everything.

At first the plan seemed to outsiders like mere midsummer madness. Then the story began to grow. Cape May residents learned that Captain Jules had found pearls in the bottom of the bay. No one would believe the captain’s statement that the pearls were of little value; gossip made the tiny pearls grow larger and larger, until they were fit for an empress.

Captain Jules was besieged at his little house up the bay, although, as usual, he kept the door fastened against intruders. Half the fishermen and oystermen in the vicinity begged to be permitted to accompany the old sea diver in his descent into the water. Captain Jules politely explained that he needed no companions; he was merely going on a diving expedition to amuse two of his friends, Phyllis Alden and Madge Morton, who had a taste for watery adventure. He did not expect to find anything of value in the bottom of the bay. They were going down merely for sport.

There was one person at Cape May who listened eagerly to any tale of the fabulous riches that the old pearl diver was evidently expecting to unearth. He was Philip Holt. The time of his visit at Cape May was rapidly passing. Mrs. Curtis was exceedingly kind and interested in her guest, but Philip did not feel that he dared approach her too abruptly with the request for so large a sum of money as five thousand dollars. Besides, Philip Holt knew that Tom Curtis disliked him heartily. Tom was not likely to approve a man whom Madge mistrusted; nor would Mrs. Curtis give away or lend five thousand dollars without first consulting her son. So the marvelous tale of the pearls to be found in the Delaware Bay rooted itself in Philip Holt’s imagination. Here was another way to get out of his scrape. He was not fond of adventure, but he would do anything in the world for money. Perhaps he could find pearls enough not only to pay his debt, but to make him rich forever afterward.

Quietly, and without a word to any one, Philip Holt made a secret visit to the house of the three sails. He implored Captain Jules to make him his diving companion. He attempted to bribe him with sums of money that he did not possess. He even threatened the old sailor that he would make investigations about his life and expose any secrets that the captain might wish to keep. Captain Jules only laughed at these threats. He was not going down in the bay for treasures, he declared. He expected to find absolutely nothing of any value. Positively he would not allow any one to accompany him but the two girls.

Madge and Phyllis had a hard fight to persuade Miss Jenny Ann to give her consent to their plan for playing mermaid. But she was getting so accustomed to the exciting adventures of her girls that, when Captain Jules assured her there was really no special danger, so long as he kept a close watch on the diver with him, she finally agreed to the scheme. Captain Jules gave the two girls every kind of instruction in the art of diving that he thought necessary, and the day of the great watery adventure was set for the week ahead.

On the morning of Tuesday, July 12th, Madge awoke at daybreak. She felt a delicious, shivery thrill pass over her that was one part fear and the other part rapture.

“Phil,” she whispered a few seconds later, when she heard her chum stirring in the berth above her, “can you feel fins growing where your feet are? Your flop in the bed sounded as though you were a real mermaid! Just think, at ten o’clock sharp we are going down to explore a new world! I wonder if there were ever any girl divers before? You are awfully good to let me go down first.”

“No, I am not,” answered Phil soberly. “If there is any danger, I am letting you go down to it first. But I shall watch above the water, with all my eyes, to see that everything goes right. The captain has explained the whole business of diving to us so thoroughly that I believe I can tell if anything is wrong with you below the surface. You’ll be careful, won’t you, Madge? You know you are usually rather reckless. Don’t stay down too long.”

“Oh, Captain Jules won’t let me be reckless this time. We are not going down into very deep water, anyway, and a professional diver can stay under several hours when the water is only about five fathoms deep.”

Madge and Phyllis ate a very light breakfast. Captain Jules had told them that a diver must never go down into the water on a full stomach, as it would make him too short-winded. While the two prospective divers were eating poor Miss Jenny Ann was wondering what had ever induced her to give her consent to so mad an enterprise as this diving.

Every effort had been made to keep a crowd away from the pier from which Captain Jules meant to send out the boats with the tenders, who were the men to look after the safety of Madge and himself.

As the girls came up, with Miss Jenny Ann, to join Captain Jules they saw twenty or thirty people about. Mrs. Curtis and Tom, accompanied by Philip Holt, had come down to the pier. Mrs. Curtis would hardly speak to Madge, she was so angry at the risk she believed the little captain was running. She and Madge had not been very friendly since they had disagreed so utterly in Madge’s report of the real character and name of Philip Holt.

Madge and Phyllis each wore a close fitting, warm woolen dress. Madge had tucked up her red-brown curls into a tight knot. Her eyes were glowing, but her face was white and her lips a little less red when Captain Jules came forward to fasten her into her diving suit.

“Don’t attempt it, Madge, if you are frightened,” urged Miss Jenny Ann, who was feeling dreadfully frightened herself. “I am sure Captain Jules will forgive you if you back out.”

Captain Jules looked at Madge searchingly. Her eyes smiled bravely into his, although her heart was going pit-a-pat.

“Miss Madge is not afraid,” answered Captain Jules curtly. “Robert Morton’s daughter has no right to know fear.”

Madge first slipped her feet into a pair of heavy leather boots. She gave a gay laugh as she slipped into her rubber cloth suit, which was made in one piece. “I feel just like a walrus,” she confided to Tom Curtis, who was watching her with set lips.

Then Madge and Captain Jules, who was in exactly the same costume, got into their boats and moved out a little distance from the shore.

Tom Curtis had asked Captain Jules’s consent to sit in one of the boats with Phil. At the last moment Philip Holt stepped calmly into the other. No one stopped to argue with him, or to thrust him out; the whole party was too much excited.

Not for all the pearls in all the seas would Captain Jules Fontaine have allowed one hair of Madge’s head to be injured. But he really did not believe that she would be in any danger under the water with him. He had arranged every detail of the diving perfectly. He would watch her every movement at the bottom of the bay. To tell the truth, Captain Jules was immensely proud of Madge’s and Phil’s bravery in desiring to accompany him.

The final moment for the dive arrived. Madge waved her hand to the crowd of her friends lining the shore. She flung back her head and looked gayly, triumphantly, up at the blue sky above her, with its sweep of white, sailing clouds. Below her the water looked even more deeply blue.

“Remember, Madge,” whispered Captain Jules calmly, “the one quality a diver needs more than anything else is presence of mind. Keep a clear head under the water and nothing shall harm you, I swear. But above all, don’t forget your signals.”

With his own hands Captain Jules fastened the brass corselet about Madge’s slender neck and set a big copper helmet which he screwed over her head to her corselet. Madge then surveyed the world only through the glass windows at each side of her head and in front. Her air-tube entered her helmet at the back. Two men in one of the boats were to keep the young girl diver supplied with oxygen by pumping fresh air down through this tube.

A moment later Captain Jules stood rigged in the same costume as Madge.

“Steady, my girl,” Captain Jules warned her.

“Aye, aye, Captain,” returned Madge quietly, “I’m ready. Let us go down together to the bottom of the bay.”

“Pump away,” ordered the captain.

There was a splash on the surface of the clear water, a long-drawn gasp from Madge’s friends; then a few bubbles rose. Rapidly, skillfully, Madge’s tenders played out her life and pipe lines, and Madge Morton disappeared from the world of men. Captain Jules made his plunge a few seconds in advance of his companion.

In the boat where Tom Curtis and Phyllis Alden sat there was a breathless, intense silence. The boy and girl happened to be in the boat with the men who were looking out for the welfare of Captain Jules. Philip Holt was with Madge’s tenders.

Phyllis knew that there was but one way in which she could follow her chum’s course below the surface of the water. She could watch her life and air lines. Captain Jules had made it plain to Phyllis that all the time the diver is under water small ripples will appear near his air line. These bubbles are caused by the air that the diver breathes out from the valve in the side of his diving helmet.

Phyllis watched the lines doggedly. Captain Jules was to keep Madge under water only about fifteen or twenty minutes, but at that a minute may appear longer than an hour.

Suddenly Phyllis Alden discovered that the man who was tending Madge’s air pump seemed to be working less vigorously. He pumped unevenly. Once he swayed, as though he were about to fall over in his seat.

In a second it flashed over Phyllis that the man was ill. He was a strong, red-faced individual, but his face turned to a kind of ghastly pallor. It was all so quick that Phil had no time to speak from her boat. Philip Holt, who was in the same boat with the man, grasped the situation as quickly as Phyllis did. With a single motion he took the tender’s place at the air-pump. Phil saw that he was pumping away with vigor.

At this moment Phil turned to speak to Tom Curtis. “Tom, how long have they been under the water?” she whispered.

“Ten minutes,” returned Tom, glancing hastily at his watch.

“It seems ten hours,” murmured Phil, as though she dared not speak aloud.

Tug, tug! Phil thought she saw Madge’s air line give two desperate jerks. Two pulls at the line was the diver’s signal for more air. Phil knew that without a doubt. Yet Philip Holt seemed to be pumping vigorously. At least, he had been only the second before when Phil last looked at him.

Again Phil saw Madge’s air line jerk twice.

Tom Curtis and the two men in Captain Jules’s boat were vainly trying to interpret some signals that Captain Jules was making to them. The two boats were at no great distance apart.

“I am afraid something is the matter below, Phil,” Tom Curtis turned to mutter hoarsely. But Phyllis Alden, who had been sitting near him a moment before, was no longer there.

Phyllis believed she saw that Philip Holt was only pretending to pump sufficient air down to Madge. She may have been wrong. Who could ever tell? But Phil knew there was no time to discuss the matter. One minute, two minutes, five or ten—Phil did not know how long a diver at the bottom of the water can be shut off from his supply of fresh air and live. She did not mean to wait, to ask questions, or to lose time. Phil made a flying leap from the skiff that held her to the one in which Philip Holt sat by the air-pump. She landed in the water, just alongside the boat. Quietly, though more quickly than she had ever moved before in her life, Phil climbed into the boat and thrust Philip Holt away from the air pump. In the minute it had taken her to make her plunge she had seen Madge’s signal again, but this time the line jerked more feebly than it had before.

Phil set the pump to working again; the signal answered from below, “All is well!”

The tender had recovered from his attack of faintness and resumed his work at Madge’s airline.

But Philip Holt sat crouched in the bottom of the boat, his face white with anger. What would Phyllis Alden’s action suggest but that he was trying to suffocate Madge in the water below?

Whether or not Philip Holt meant to stifle Madge Morton he himself never really knew. The impulse came to him as he placed his hands on her air-pump. It flashed across his mind that it was Madge who had tried to injure his prospects with Mrs. Curtis, and who had kept him from going down with Captain Jules to search for the pearls that he firmly believed would be found at the bottom of the bay. It was while these thoughts passed through Philip Holt’s mind his pressure on Madge’s air-pump had wavered. But Phyllis Alden had discovered it. She gave him no opportunity either for action or regret.