The boat was barely creeping now. It seemed to be struggling against some invisible force that gripped gently but relentlessly, some infinitely patient force that from the very patience of its operation was the more evidently inexorable.
The engines were working in panic-stricken tempo now. The chief engineer had given them all the steam they would take, and the propellers thrashed the water mightily, but the ship slowed, slowed.
At last it was still, while the engines seemed to be trying to rack themselves to pieces in their terrific attempt to drive the ship against the Thing that held it back.
The captain watched with a set face, then ordered the engines reversed. There was an instant's pause, and the propellers took up their thrashing of the water again. For a moment it seemed that they would have some effect. The yacht shivered and moved slightly backward, but then stopped again with the same soft gentleness.
The seamen inspected the water all around the ship with lanterns lowered to the water's edge. They found nothing. A sounding line was thrown overboard, and sank for two hundred fathoms without reaching bottom.
The searchlight played endlessly over the water, trying to find some turmoil that might indicate the presence of a monster whose tentacles had fastened upon the ship, but without result. The surface of the water was like glass.
Again and again the engines struggled mightily to move the ship. Again and again the propellers beat the water at the stern into froth and foam, but never did the yacht move by as much as an inch.
The sea was calm and placid. The stars looked down from the moonless sky and were reflected by the still surface of the water.
The yacht struggled like a living thing to break free from the mysterious force that held her fast, while all about her there hung that faintly disgusting odor of slime from the depths of the sea, an indistinctly musky odor as of something unclean.
At last the wireless began to crackle a frantic appeal for help, giving the details of what was happening on board the yacht. Hardly had the message finished when the yacht began to rock slightly, as from a faint ground swell.
CHAPTER II.
"But, Theodore, old pet," said Davis amiably. "The fact that a plane won't loop the loop or make nose dives at ninety degrees doesn't make it hopeless as a battleplane."
He was affectionately expounding the good points of a monster seaplane drawn up in its hangar by the beach.
Davis wore the insignia of a flight commander of the aviation corps and the ribbons of half a dozen orders bestowed on him after the destruction of the Black Flyer, destroyed by Teddy Gerrod and himself some six months before.
Teddy Gerrod was in civilian clothes, but was earnestly, though cheerfully, disputing everything his friend said.
"A two-seater like the one we used six months ago," he pointed out, "could fly rings around this bus of yours, and with a decent shot at the machine gun could smash it in no time."
"Fly rings around it? Not noticeably," said Davis confidently. "Since our idea of platinum plating the cylinders everybody's doing it. Using picro gasoline, as you and I did, we get a hundred and eighty miles an hour from this 'bus' you're trying to disparage. And, furthermore, if you try to damage this particular ship with machine-gun bullets you're going to be disappointed."
"Armor?"
"Precisely. I admit cheerfully that you may know a lot about physics and cold bombs and liquid gases and such things, but when it comes to flying machines—my dear chap, you simply aren't there."
Gerrod laughed.
"Perhaps not. But I'd rather dance around in a more lively fashion in a little two-seater."
"And privately," admitted Davis, "so would I. The next war we have I'm going to arrange for you to be my machine gunner."
"Delighted," said Gerrod. "But what would Evelyn say?"
He was referring to his wife. Davis waved his hand.
"Oh, she'd say there aren't going to be any more wars."
"That reminds me," said Gerrod. "We want you down for the next weekend. No other guests."
Davis nodded abstractedly. A messenger was coming over to the hangar at double time.
"Thanks. I'll be glad to come. Wonder what this chap wants?"
The messenger came up, saluted, and handed Davis a yellow slip. Davis tore it open and read:
Steam yacht Marisposita, Alexander Morrison of New York, owner, reports position 33°11'N 55°10'W, wants immediate assistance. Engines and hull perfect condition, not aground, no derelict or obstacle discoverable. Unable to move any direction. Sea calm. Only possible explanation has been seized by sea monster. Flt. Comm. Richard Davis ordered to make reconnaissance of situation in seaplane. Reported condition considered incredible, but no naval vessels in immediate vicinity. Flt. Comm. Richard Davis will make immediate investigation and report.
Davis whistled.
"Here's something pretty!" he remarked. "Take a look."
He handed the order to Gerrod and went quickly to the door leading into the workshop attached to the hangar.
In a few crisp sentences he had ordered the big plane prepared for an extended flight, with provisions and as much fuel as it would carry. He returned to find Gerrod thinking busily.
"May I come along on this trip?"
"It's against regulations, of course," said Davis, "but no one will kick if you go. You're privileged."
He cried an order or so at the workmen, who were now swarming over the machine.
Although the wireless message had been sent from the yacht after nightfall, the sun was barely setting on the coast, where the hangar was placed.
The vessel in distress was some thirty degrees east of the coast, and consequently the sun set two hours before it sank on the coastal line.
Gerrod phoned a hasty message to his wife and went to Davis' quarters, where he borrowed heavy flying clothes from Davis' wardrobe. The mechanics and helpers worked with desperate haste.
The aëroplane would be flying all night long, but it was desirable that it take off while there was yet some light. The long fuel tank was filled, and the motors run some ten or fifteen minutes, while critical ears listened for the faintest irregularity in their bellowing roar.
Two engineers and a junior pilot were to go with Davis in the big aircraft, and they were hastily summoned and told to prepare to leave in as short a time as possible.
It was hardly more than half an hour from the time the telegraphed order was received before Gerrod preceded Davis up the ladder and into the inclosed cabin of the seaplane.
The motors were cranked—two men tugging at the blade of each of the huge propellers—and the plane slid slowly down the ways and into the water.
Davis maneuvered carefully until he was clear of all possible entanglements. Then he gave the motors more gas and more. Their harsh bellow rose to a deafening sound, and the long, boatlike body began to surge through the waves with gradually increasing speed.
For a few yards the spray blew upon and spattered the glass windows of the cabin. Then the planes began to exert their lifting power and the plane began to ride the waves instead of plowing through them.
The speed increased again, and suddenly the shocks of the waves beating on its under surface ceased. The plane rode upon air with a smooth and velvety motion that was sure and firm.
Davis rose gradually to five thousand feet and headed accurately to the east. A southerly wind, reported by wireless from a ship at sea, would carry him slightly to the south, and the sum of the two motions should bring him, by dawn, very close to the spot from which the yacht had sent out her wireless call.