That night, as they sat by the camp fire they noticed a great confusion among the gulls.

They seemed quarreling all along the western side of the reef. The voice of the gulls was one of the familiar sounds of the island, but not after dark. To-night they were clamorous.

They broke out again before dawn, and Floyd, listening, noticed a new note in their voices. They seemed not quarreling one with another, but against some common enemy. Then the sound died away little by little, and when he came out of the tent there was not a gull to be seen near the reef opening, where as a rule they congregated in numbers.

The sunrise was clouded, and the sun did not strike the sea till half an hour later than his ordinary time. The wind that had been blowing so strongly yesterday had died away, yet the boom of the surf on the reef was louder than on the day before.

Floyd crossed the reef close to the wreck and looked seaward.

A glacial calm held the sea, a calm underrun by a tremendous swell. A long, tremendous swell, an infinite heaving of the very depths of the ocean finding[Pg 70] expression here in acre-wide undulations, solemn, slow to the eye, rhythmical and sonorous.

The beating of the breakers seemed ruled by a metronome.

There was no little wave and big wave, no hesitation of the sea. The breakers were equidistant and equal in volume, and their pace was set to the same funeral march.

Schumer came out of the tent, and, catching sight of Floyd, walked toward him.

"There must be a lot of damp or electricity or something in the air," said he. "I feel like a rag."

"Look at the sea," said Floyd; "there has been a big storm somewhere, if I am not greatly mistaken."

Schumer stood looking at the sea.

The sun seemed bright as ever, yet the water did not respond to his light; it had at once a surface brilliancy and a dullness in its depths. Toward the shore it was bottle green, and even the blue far out had a trace of tourmaline.

Schumer said nothing, and turned away to the camping place, where Isbel was making the fire.

"Shall we go on with the diving to-day?" asked Floyd, as they breakfasted.

"I don't feel like work," said Schumer; "besides, I doubt if it would be any use. There's a huge, big storm coming, if I am not mistaken. I feel it in my skin, and I feel it in my nerves. I suppose it's the electricity in the air, but I believe I'd spark if you touched me with a bit of metal. Listen! There go the gulls again."

Away on the reef beyond the fishing ground, so far away that their voices came indistinctly on the windless[Pg 71] air, the gulls were crying again, and, standing up, Floyd could see them in wild flight about the reef like scraps of blown white paper.

Then they rose higher, continued their argument, and began to recede.

"They are off," said Floyd; "going out seaward, the whole lot of them. By Jove, that looks like business!"

"They know what's coming," said Schumer, "and they are clearing out of the track. Wonder what tells them. Instinct, I suppose."

He set off to examine the cache, taking Floyd with him. He had covered the perishable stuff with sailcloth, and he now set to make the lashings more secure. They worked an hour, and when they came out again the sun had lost his brilliancy—a vague mist hid the horizon on every side.

In the northwest this thickness seemed more dense, and the sea, still glassing in and breaking in rhythmical thunder on the reef, had turned to the color of lead.

But for the noise of the surf the silence was now absolute and complete.

It held so till noon, when a wind began to stir the palm tops; a wind that seemed to come from nowhere, rocking them and tossing them hither and thither, making cat's-paws on the lagoon, and flicking at the tent canvas like a worrying hand.

Schumer took down the tent.

He had already placed the valuables in a place of safety. He had dug out a hole beneath one of the trees and buried the cash box containing the money and pearls.

"You never know," he said, "if it's a cyclone that's coming. Nothing is safe above ground. A cyclone[Pg 72] would lift an anvil; anyhow, this will be safe enough."

An hour after noon the great storm showed itself.

Away above the northwestern horizon a black line appeared, hard and distinct as the outline of a country.

It did not seem to advance—it rose. Till now it assumed the appearance of a wall. As it rose, it lightened to a dark copper color, and as it rose it lengthened, so that now it occupied the whole horizon from east to west.

The rapidity of this development was appalling, and the sun, as if shrinking before the coming attack, paled still more, dimmed as by a partial eclipse.

Now the wind came steady and strong, whipping the lagoon and bending the foliage, and then all at once dying away again into absolute stillness.

It was in this great pause that they heard a sound never to be forgotten; less a sound than a vibration—deep and almost musical, like the vibration of a great glass rubbed by a wet finger.

Isbel, who had remained on the reef near the wreck while the two men had gone for a moment toward the lagoon edge, called out suddenly, and they turned and came toward her.

Even as they turned, the first blast of the wind struck them, and, battling against it, they reached where the girl was crouching, pointing to the sea.

The sea beyond the limit of a mile or so was flat as a board, b............