"I don't understand yet how you mean to work the thing," said Steevens.

"In the first place, I'm screwed into the sphere," said Elstead, "and when I've turned the electric light off and on three times to show I'm cheerful, I'm swung out over the stern by the crane, and all those big lead sinkers slung below me. The top lead weight has a roller carrying a hundred fathoms of strong cord rolled up, and that's all that joins the sinkers to the sphere, except the slings that will be cut when the affair is dropped. We use cord rather than wire rope because it's easier to cut and more buoyant--necessary points, as you will see.

"Through each of these lead weights you notice there is a hole, and an iron rod will be run through that and will project six feet on the lower side. If that rod is rammed up from below, it knocks up a lever and sets the clockwork in motion at the side of the cylinder on which the cord winds.

"Very well. The whole affair is lowered gently into the water, and the slings are cut. The sphere floats--with the air in it, it's lighter than water--but lead weights go down straight and the cord runs out. When the cord is all paid out, the sphere will go down, too, pulled down by the cord."

"But why the cord?" asked Steevens. "Why not fasten the weights directly to the sphere?"

"Because of the smash down below. The whole affair will go rushing down, mile after mile, at a headlong pace at last. It would be knocked to pieces on the bottom if it wasn't for that cord. But the weights will hit the bottom, and directly they do, the buoyancy of the sphere will come into play. It will go on sinking slower and slower; come to a stop at last, and then begin to float upward again.

"That's where the clockwork comes in. Directly the weights smash against the sea bottom, the rod will be knocked through and will kick up the clockwork, and the cord will be rewound on the reel. I shall be lugged to the sea bottom. There I shall stay for half an hour, with the electric light on, looking about me. Then the clockwork will release a spring knife, the cord will be cut, and up I shall rush again, like a soda-water bubble. The cord itself will help with the flotation."

"And if you should chance to hit a ship?" said Weybridge.

"I should come up at such a pace, I should go clean through it," said Elstead, "like a cannon ball. You needn't worry about that."

"And suppose some nimble crustacean should wiggle into your clockwork--"

"It would be a pressing sort of invitation for me to stop," said Elstead, turning his back on the water and staring at the sphere.

They had swung Elstead overboard by eleven o'clock. The day was serenely bright and calm, with the horizon lost in haze. The electric glare in the little upper compartment beamed cheerfully three times. They let him down slowly to the surface of the water, and a sailor in the stern chains hung ready to cut the tackle that held the lead weights and the sphere together. The globe, which had looked so large on deck, looked the smallest thing conceivable under the stern of the ship. It rolled a little, and its two dark windows, which floated uppermost, seemed like eyes turned up in round wonderment at the people who crowded the rail. A voice wondered how Elstead like the rolling.

"Are you ready?" sang out the commander.

"Ay, ay, sir!"

"Then let her go!"

The rope of the tackle tightened against the blade and was cut, and an eddy rolled over the globe in a grotesquely helpless fasion. Someone waved a handkerchief, someone else tried an ineffectual cheer, a middy was counting slowly: "Eight, nine, ten!" Another roll, then with a jerk and a splash the thing righted itself.

It seemed to be stationary for a moment, to grow rapidly smaller, and then the water closed over it, and it became visible, enlarged by refraction and dimmer, below the surface. Before one could count three it had disappeared. There was a flicker of white light far down in the water, that diminished to a speck and vanished. Then there was nothing but a depth of water going down into blackness, through which a shark was swimming.

Then suddenly the screw of the cruiser began to rotate, the water was crickled, the shark disappeared in a wrinkled confusion, and a torrent of foam rushed across the crystalline clearness that had swallowed up Elstead.

"What's the idea?" said one A.B. to another.

"We're going to lay off about a couple of miles, 'fear he should hit us when he comes up," said his mate.

The ship steamed slowly to her new position. Aboard her almost everyone who was unoccupied remained watching the breathing swell into which the sphere had sunk. For the next half-hour it is doubtful if a word was spoken that did not bear directly or indirectly on Elstead. The December sun was now high in the sky, and the heat very considerable.

"He'll be cold enough down there," said Weybridge. "They say that below a certain depth sea water's always just about freezing."

"Where'll he come up?' asked Steevens. "I've lost my bearings."

"That's the spot," said the commander, who prided himself on his omniscience. He extended a precise finger southeastward. "And this, I reckon, is pretty nearly the moment," he said. "He's been thirty-five minutes."

"How long does it take to reach the bottom of the ocean?" asked Steevens.

"For a depth of five miles, and reckoning--as we did--an acceleration of two feet per second, both ways, is just about three-quarters of a minute."

"Then he's overdue," said Weybridge.

"Pretty nearly," said the commander. "I suppose it takes a few minutes for that cord of his to wind in."

"I forgot that," said Weybridge, evidently relieved.

And then began the suspense. A minute slowly dragged itself out, and no sphere shot out of the water. Another followed, and nothing broke the low oily swell. The sailors explained to one another that little point about the winding-in of the cord. The rigging was dotted with expectant faces. "Come up, Elstead!" called one hairy-chested salt impatiently, and the others caught it up, and shouted as though they were waiting for the curtain of a theatre to rise.