"Gerrod," said Davis whimsically, "I am much depressed that Varrhus didn't include me with you as making efforts to obstruct his plans and desires."
"The government will have to be notified," said the commissioner of police solemnly.
"Do—do you think I had better go?" asked Evelyn hesitatingly.
"No!" exploded Teddy and Davis together. Teddy went on: "Why, Evelyn, the man is insane! And besides we've just thought of something that's sure to get him. We'll lay in wait for him, and then he'll walk into our parlor nicely. When he does———"
"Finis," said Davis cheerfully, "if I may borrow a phrase from the French."
"And if it's a long chase," said Teddy even more cheerfully, "the dear person set the time for dawn, and we'll have light to fight by. Let's go and set to work on that plane of yours."
They left together in high spirits. Evelyn stood quite still after they had gone, absently crushing the letter from Varrhus in her hand. Presently, with a sob, she went to her room and allowed herself to cry. They would not let her face danger, but Teddy was going out to fight, perhaps to die—and for her.
Over at the hangar, mechanics swarmed upon the fighting plane, dismounting the motors and disassembling them. The cylinders and pistons were being carefully packed. A big motor truck had already backed up at the wide door of the aëroplane shed, and as fast as the parts were packed they were loaded on it. Davis was here, there, and everywhere. He had asked permission for the experiment, and it has been granted. The government was prepared to risk almost anything rather than allow Varrhus to succeed in his huge blackmailing of the entire human race. There was no hesitation in allowing anything that might afford a fighting chance of downing the black flyer. The Mississippi floods were growing in size and destructiveness. The New York cold bomb, dropped the night Teddy and Davis had fought the black machine over the harbor, was expected to explode at any moment. Every window still intact in the city had been pasted with strips of paper to keep the fragments from becoming a menace to those on the streets when the bomb should burst them.
Davis had conferred with the commandant of the forts, and volunteers had been asked for among the garrison. A boat was being heavily armed with concealed guns. It would go to the point where Varrhus would expect Evelyn to be taken. He would see the small boat, drop down to take Evelyn on board his evil craft, and the masked batteries of anti-aircraft guns would open on him in a blast of fire. Teddy's discovery that flares fired into the cloud of liquified gas would cause it to burn harmlessly in mid-air had been adapted to protect the crew. As the guns opened on the hovering black flyer a stream of fire balls would be made to float overhead to set flaming the stream of liquid hydrogen Varrhus might be expected to shoot downward. At that, though, the mission of the boat crew was hazardous in the extreme.
The telephone rang in the hangar. Teddy was on the wire. He had commandeered the big wooden acid vats of an electro-plating plant, and the platinum-plating solution was being mixed even then. If Davis brought the motors over in parts, the plating might begin immediately.
The big truck rumbled off, Davis smiling confidently on the seat beside the chauffeur. Half a dozen mechanics perched on various parts of the load. When the truck stopped before the electro-plating plant they leaped off and rushed the glistening cylinders inside. In twenty minutes they were in the plating solution and an almost infinitely thin film of platinum was slowly forming within them.
The workmen of the electro-plating plant labored far into the night on their task. Teddy had insisted that a film of platinum ten times the thickness of the usual precious-metal plating be used, and the process was slow. When the cylinders had been prepared, the pistons remained, and the exhaust ports and valves. These, too, were coated with the hard, acid-resisting metal, and Davis' mechanics began their task of fitting piston rings to the altered motor parts. The rings themselves had then to be plated, and all the plating burnished and polished. Teddy and Davis snatched a few hours' sleep while the motor in its disassembled state was being carried back to the hangar and re-installed in the aëroplane. They woke, and during all the following day Davis sat in the pilot's seat, listening with a practiced ear and aiding in the final tuning up of the changed motors, adjusting the carburetors to their new fuel. Thirty per cent of picric acid added to the finest, highest grade gasoline was to be used. No one had dared use such a percentage before, even for motors that were expected to be ruined.
Teddy, in the meantime, was familiarizing himself with the small one-pounder automatic gun—similar to the German antitank weapons—that was to be installed in the bow of the aëroplane. By nightfall all was finished. Teddy ran over to New York and saw Evelyn for the last time before making his attempt, and the next morning he and Davis flew to Noman's Reef, where a camouflaged hangar had been erected on telegraphed instructions from New York. Tuesday dawn found them alert and anxiously scanning the sky for a sign of the black flyer.
CHAPTER X.
The stars winked palely from the graying sky. In the east a pallid whiteness showed which slowly yellowed and then turned to pink. The dawn was breaking.
On the little reef men watched keenly. Far out at sea, its single funnel tipped with red paint from the crimson sunlight, a little boat tossed and rolled. That boat contained the men who had offered their lives for a chance to kill this Varrhus, who threatened the liberty of the world. Beside the camouflaged hangar two great horns, seeming to be enlarged megaphones, pointed toward the sky. Little wires ran from their points to telephone receivers strapped on the ears of intently listening men. They were microphones to detect the first sound of the musical humming of the black flyer. Teddy and Davis were befurred and goggled, but had pushed up their goggles to take powerful glasses and scan the sky eagerly for a sight of their enemy. Mechanics stood ready at the propellers of the hidden fighting plane, prepared to spin the motors into roaring life the instant the two aviators had settled in their seats. From before the wide doors of the concealed hangar a broad expanse of beach ran smoothly down to the ocean. The little boat tossed and rolled. The men at the microphones listened intently. The others searched the sky.
Straight down from a wisp of golden cloud a slim black speck fell toward the earth. At first, so high was it, even those with field glasses could make out only the thin shape of the glistening black body. It fell a thousand, two thousand feet——The whirring disks above the slender body became visible, then the inclosed cabin near the center. The musical humming filled the air. Lower and lower the strange machine dropped. Davis and Teddy were in their seats.
"Now!" said Davis sharply, and the propellers whirled. The motors caught, sputtered, and began to run with a steady, droning roar. Davis watched keenly as the black shape slowed in its fall and came to a standstill above the little, tossing boat. Half a dozen men were holding the aëroplane back, and the small shed was full of clouds of choking dust and still more choking fumes from the motor.
The black flyer hung motionless, barely three hundred yards above the small boat. There was a long moment of waiting. Then the decks of the boat seemed to fall in. A dozen threatening muzzles were exposed. A dozen flashes of flame shot up from the tiny vessel. Simultaneously Davis cried out, the men released his machine, and it darted forward. He took off from the beach skimmed the waves, and shot out toward the strange combat that was taking place.
The black flyer had been hit. That much was certain. It lurched and staggered in the air, losing altitude all the while. Then the pilot seemed to regain control. He swung swiftly to one side and began to rise. All the time the anti-aircraft guns were firing viciously. The tossing boat made a poor platform for the gunners, however, and their aim was inevitably poor. The guns kept up a ceaseless roaring. Puff after puff of white smoke showed where their shells burst near Varrhus. He began to swerve, to zigzag, using tactics strangely like those of a dragon fly. Suddenly he darted to a point exactly above the small boat, and a smoky cloud began to dart down from below his machine. Varrhus passed on, but the cloud fell swiftly, precisely like the cloud of liquified gas he had poured down on Teddy and Davis above New York harbor.