Madge felt herself in a great fairy world peopled with giants. Every thing below the water is magnified a thousandfold. Slowly she went down and down! The fishes splashed and tumbled about her, hurrying to get away from this strange, new sea-monster that had come into their midst.

The little captain felt no mental sensation except one of wonder and of awe; no physical impression save a pressure as of a great weight on her head and a roaring of mighty waters in her ears. She no longer had any idea of being afraid.

At the first plunge into the water she had shut her eyes, but now, as she approached the bottom of the bay, she kept them wide open.

The water was clear as crystal, like the reflection in a mammoth mirror. She could see nearly fifty feet ahead of her. Captain Jules walked just in front of her, swinging his great body from side to side, peering down into the sandy bottom of the bay. Madge discovered that the only way in which she could get a view, except the one directly in front of her, was by turning her head inside her helmet, to look through her side window glasses. The goggles over her eyes gave her just the view that a horse has with blinkers.

There were hundreds of things that Madge would have liked to confide to Captain Jules. However, for once in her life, she was compelled to hold her tongue. Her eyes, her hands, and her feet she could keep busy. Now and then she gave a little ejaculation of wonder inside her copper helmet at the marvels she saw. No one heard her cry out. Captain Jules wasted no time. He was exceedingly business-like. He motioned to Madge just where she should go and what she should do, and she obediently followed.

There were long, level flats of sand in the bottom of Delaware Bay, like small prairies. Then there were exquisite oases of waving green seaweed, gardens of sea flowers and ferns, and hillocks of rocks, with all sorts of queer sea animals, crabs, jelly-fish, and devil-fish, scurrying about them.

Caught in the moss, encrusted on the rocks, sunken in the yellow sands, were opalescent, shining shells and pebbles, each one more beautiful than the last. Madge did not realize that if she carried these shells and pebbles above the water they would look like ordinary stones. Every now and then the young diver would stoop and drop one of them in her netted bag with a thrill of excitement.

Again and again Captain Jules had assured Madge that she must not expect to find any pearls of much value in Delaware Bay. There were few pearls in edible oysters. The beds about Cape May were meant to supply the family table, not the family jewels. Of course, it was true, the Captain admitted, that a pearl did appear now and then in an ordinary oyster. Yet this was an accident and most unlikely to occur.

Madge had really tried not to believe that she was going to find any kind of prize in the new world under the water. In spite of all her efforts she had been thinking and planning and hoping. Perhaps—perhaps she would find a pearl of great price. Then her troubles would be at an end.

All this time Madge had been breathing naturally and comfortably inside her helmet as she traveled along the bed of the bay. She was so unconscious of any difficulty that she was beginning to believe that she was, in truth, a mermaid, and that water, and not air, was her natural element. Suddenly she felt a little uneasy, as though the windows of her room had been closed for too long a time. It was nothing, she was sure. The stifling sensation would pass in another second.

At this moment Captain Jules gazed hard at Madge. He had never forgotten his charge for a moment. But all seemed well with her, and the captain thought he saw ahead of him something that was well worth investigating. He dropped on his knees in the soft mud. With him he had a small hammer and a fork, not unlike a gardener’s. Shining through some green sea moss so soft and fine that it might have been the hair of a water-baby, Captain Jules had espied some glittering shells. To his experienced eye the glow was that of mother-of-pearl. It is the mother-of-pearl shell that usually covers the precious pearl. The old sailor set to work. Madge was eagerly watching him, when once again the faint stifling sensation swept over her. Surely it was not possible to faint in a diving suit. Besides, Madge’s heart was beating so furiously with excitement that it was small wonder she could not get her breath. She believed that Captain Jules was about to discover a wonderful pearl. He had wrenched the shells free and was trying to open them. Madge stood some feet away from him, quivering with excitement.

“‘And the sea shall give up its treasures’,” she quoted softly to herself as she watched.

The next moment her hands made an involuntary movement in the water. Had she been on land her gesture would have meant that she was fighting for breath. To her horror she realized that she was slowly suffocating. Something must have happened to her air-pump above the water. She was not faint from any other cause, but was getting an insufficient supply of fresh air.

At this moment Madge proved her mettle. She remembered Captain Jules’s injunction, “Keep a clear head under the water and there is nothing to fear.” She knew the signal for more fresh air, and gave two hard, quick pulls on her life line. Then she waited. Relief would surely come in a moment.

For the first and only time since their descent to the bottom of the bay Captain Jules had temporarily neglected Madge. He certainly had not expected to find any pearls in so unlikely a place as Delaware Bay; yet the shells he held in his hand were most unusual. The thrill of his old occupation seized hold of the pearl fisher. His big hands fairly trembled with emotion. He felt, rather than saw, Madge jerk her life line twice, but it never dawned on him that her signal for more air might fail to be answered.

Madge signaled again. A loud buzzing seemed to sound in her ears. Her tongue felt thick and swollen. She could not see a foot ahead of her. All the dazzling, shimmering beauty of the world under the water had passed into blackness. The little captain’s eyes were glazing behind the glass windows of her helmet. She felt that she must be dying. But she had strength to give one more signal. Air! air! How could she ever have believed that there was anything in the world so precious as fresh air? Madge had a vision of a field of new-mown hay in her old home at “Forest House.” The wind was blowing through it with a delicious fragrance. Had she the strength to pull her life line once again? The water that she loved so dearly was to claim her at last. She made a motion to go toward Captain Jules, but she had no control of her limbs.

Then Captain Jules became aroused to action. He realized that Madge had signaled for air, not once, but several times. This meant that her signal had not been answered. The captain had been for too many years a deep-sea diver not to guess instantly the girl’s condition. The groan inside his helmet came from the bottom of his heart. Captain Jules’s hands shook. He dropped the shells that he believed might contain priceless pearls down into the soft sand in the bed of the bay.

It was at this moment that Tom Curtis and Phyllis Alden, as well as the captain’s boat tenders, caught his confusing signals from below. More fresh air was pumped down the tube to Captain Jules, but not to Madge.

Phil’s leap and quick work at Madge’s air-pump must have taken place not more than three minutes afterward, but they were horrible, agonizing moments. Madge hardly knew how they passed. Captain Jules suffered the regret of a lifetime. How could he have been so unwise as to entrust the safety of this girl, whose life was so dear to him, to the perils of a diver’s experiences? In the few weeks of their acquaintance Madge Morton had become all in all to Captain Jules Fontaine.

There was but one thing for Captain Jules to do for his companion. He must signal to have her drawn up to the surface of the water again, trusting that she would not suffocate for lack of air in her ascent.

Madge was near enough to lay her hand on Captain Jules’s arm. Phil’s relief had come just in time. The life-giving fresh air from the world above pressed into her copper helmet. It filled her nose and mouth, it poured into her aching lungs. She received new life, new energy. Now she was no longer afraid. She did not wish to go above the surface of the water. Surely all above was now well. She yearned to continue her adventures on the under side of the world.

She it was, not Captain Jules, who dropped down on her hands and knees to grope for the captain’s lost pearl shells.

But the sand had covered them up forever, or else the water had carried them away!

Captain Jules wished to take Madge out of the water immediately, yet he yielded for a minute to her disappointment. What treasures had they lost when he threw the mother-of-pearl shells away? Neither of them would ever know. The old diver looked about in the soft mud, while Madge raked furiously near the spot where she thought the sailor had dropped the shells. Captain Jules walked on for a little distance. He had seen beyond them a tangled mass of other shells and seaweed and it occurred to him that the water might have carried his shells into some hidden crevice nearby.

But Madge never left her chosen spot. Deeper and deeper she dug. What a swirl of mud arose and eddied about her, darkening the clear water in which she stood! The little captain’s hammer struck against something hard. Was it a rock embedded in the sand? Yet a distinct sound rang out, as of one metal striking against another!

Madge did not know how she summoned Captain Jules back to her side. She was wild with curiosity and excitement. Captain Jules was smiling behind his copper mask. The young girl diver had probably found a piece of old iron cast off from some ship. Still, she should unearth whatever she had discovered so near the dark kingdom of Pluto.

The captain worked with her. Whatever her find might be, it was larger and heavier than Captain Jules had expected. They could afford to spend no more time with it. It was time for Madge to leave the water.

It is difficult to make an imploring gesture in a diver’s suit. Yet, somehow, Madge must have managed to do so. For one moment longer the old pearl diver relented. The hole that they were digging in the bottom of the bay was widening before them. A chunk of what looked like solid iron was visible. Then a triangular end came into view. It was rusted until it shone like beautiful green enamel. The top was absolutely flat and of some depth, as it was so hard to excavate.

The time was growing short. Madge had been under the water as long as was safe for any amateur diver. The captain was a man to be obeyed, as she knew instinctively. She gave one more dig into the mud about her iron treasure. It now became plain, both to her and to Captain Jules, that she had found an old iron chest. The captain tugged at it with both his great, strong hands. It was strangely heavy. But he managed to lift it in his arms.

Straightway he gave the signal to ascend; three sharp tugs at his life line. Madge followed suit. But she cast one long backward glance at the watery world into which she might never again descend, as slowly, steadily, the boat tenders pulled up her long life line. Her feet dangled above the sandy bottom of the bay. Now she could see even farther off. About forty feet from the rapidly filling hole from which she and the captain had extracted the iron chest was a spar of a ship jutting above the sand. The little captain may have been wrong, but it looked like the very spar on which Tania’s dress had caught the day she was so nearly drowned. Madge could not tell how far she and Captain Jules had traveled on the bottom of the bay, but she knew they had made their descent at a place no very great distance from the spot where Roy Dennis’s yacht had run down their skiff, and Captain Jules had rescued Tania and herself.

Thought travels swifter than anything else in the created world. So Madge’s thoughts had reached the upper world before she followed them. She wondered if the girls would be very sadly disappointed when she returned bearing, instead of a costly pearl, nothing but a rusted iron box!

Would Phil have better luck when she descended to the depths of the bay? What had happened in the outside world since she had disappeared from it a long, long time ago?

A flare of blinding sunlight smote across the glass goggles in Madge’s copper helmet. She felt herself picked up and lifted bodily into a boat. Her helmet and corselet were unscrewed. She lay still, smiling faintly as the boat made for her friends who crowded, watching, on the pier. Captain Jules, bearing the small iron chest, landed a moment later. The little captain had been in a new world, into which few men and rarely any women have ever entered. She had been out of her human element, a creature of the water, not of the air, and it seemed to her that she must have lived a whole new lifetime as a deep-sea diver.

Tom Curtis stared anxiously at his watch and smiled into her white face. He breathed a sigh of relief and of wonder. Captain Jules Fontaine and Madge Morton had been down at the bottom of Delaware Bay exactly thirty minutes!