"We'll fix that in a hurry," said Davis briskly. "Oh, Simpson! Come here!"
In twenty minutes there were half a dozen mechanicians at work, and Teddy was carefully inspecting the machine gun at the bow of the fusilage.
Teddy telephoned back to Evelyn what he anticipated would occur that night and his own share in it.
"Of course there's some risk in it," he finished, "but I guess we'll come out."
Evelyn's voice was more anxious than Teddy had expected.
"Do be careful, Teddy," she said in a worried tone. "Please be very careful. Varrhus has so many fiendish weapons. I'm terribly afraid."
Teddy's voice was grim.
"With the kind assistance of the German government," he remarked, "we have a few fiendish inventions, too. I'm using explosive bullets only to-night. Varrhus is outlawed."
Evelyn spoke almost faintly.
"But take good care of yourself, please, Teddy," she urged. "It were better that Varrhus got away this once than that you should be killed for nothing."
Teddy smiled. "I've no intention of being killed, Evelyn, but I have some intention that Varrhus shall be."
There was a curious sound from the other end of the wire.
"But—but——" Evelyn's voice died away. "I'm—I'm going to be praying, Teddy. Good-by."
The last was very faint. Teddy turned from the instrument and went out to where the aëroplane had been rolled from its shed. The sun was sinking and dusk was falling. Time passed and darkness settled down upon the earth. Stars twinkled into being. A long searchlight poked a tentative finger of light into the sky.
"We'd better be going," said Davis thoughtfully. "We want to be well up before he appears."
Teddy clambered up to his seat and adjusted the straps that would hold him in place. He pulled down the helmet and fitted the telephone receivers securely over his ears. A telephone was necessary for communication with Davis, four feet behind him, because of the tremendous roar of the engines. He took the machine-gun butt and found the trigger, then made sure the first of a belt of cartridges was in place. He settled back in his seat as the mechanics began to twirl the propellers. He was going out to fight the black flyer, but most incongruously he was not thinking of Varrhus at all. His thoughts dwelt with strange intensity upon Evelyn.
CHAPTER VIII.
New York lay below them. The long, straight lines of lights shining up through the semidarkness of the moonlit night made a strange appearance to the two in the swift machine. Davis had mounted to a great height, some ten thousand feet, and the pin points of light outlined more than a dozen cities and towns. The Hudson was a faintly silvery ribbon flowing down placidly from a far-distant source. Because of the ice cake in the Narrows its level had risen two or three feet, but now it flowed smoothly over that great obstacle, melting and carrying it away toward the sea.
The fighting plane roared around in huge circles, seeming strangely alone in the vast expanse of air. One searchlight from below moved restlessly about the sky. A second joined it, then a third. One by one a dozen or more of long, pencil-like beams of light shot up into the sky and moved here and there in seeming confusion, but actually according to a carefully prearranged plan. A hooded red light showed below the biplane in which Teddy and Davis were awaiting some sign of the black flyer. That had been agreed upon, and none of the searchlight beams flashed upon the circling machine. From time to time Davis shut off the motors, and the two of them lifted the ear flaps of their helmets to listen eagerly for the musical humming that would herald Varrhus' approach.
Far to the east they could see where the faintly luminous waters of the ocean came up to and stopped at the darker masses of the land. The harbor below them glittered in the moonlight. The only peculiarity in the scene was the absence of the little harbor craft that ply about busily by day and night upon their multifarious errands. They were all securely docked. The wharves, too, were dark and silent. All the maritime industry of New York was at a standstill.
A wide spiral to twelve thousand feet. The motors were hushed during a two-thousand-feet glide, while the two men in the machine listened intently. For two hours this maneuver had been repeated and re-repeated. No sound save the rush of the wind through the guy wires and past the struts had broken the chilly stillness of the heights. The sky was a blue dome of a myriad winking lights. A pale silver moon shone down.
The nose of the machine pointed down and the motors ceased to roar. Faintly but unmistakably above the whistling and rushing of the wind about the surfaces of the biplane a deep, musical humming could be heard. Abruptly the motors burst into life again. The exhausts began to bellow out their reassuring thunder. The machine began to climb again, circling to every point of the compass, while Teddy and Davis scanned the sky keenly for a sign of the black flyer with its cargo of menace to New York.
"I'm going to fifteen thousand."
Davis' voice sounded with metallic clearness in Teddy's ear. The telephones between the two helmets were working perfectly.
"That was Varrhus, all right?" said Teddy quietly. "Did you signal to the people beneath?"
Davis pushed a button, and a green light glowed beside the red one in the hood below the machine. In a moment the receipt of this signal by those below was evidenced. The searchlights took up their task with renewed vigor, searching the sky frantically for a sign of the black flying machine. The hood below the biplane allowed the signal to be seen by those on the ground, but made the light invisible to any one in the air. The biplane swung in wide circles, Teddy and Davis with every nerve taut and every sense alert, aflame with eagerness to sight their quarry. They saw it, outlined for an instant by the white beam of one of the circling lights.
It was dropping like a stone from the clouds. The searchlight rays glistened from polished black sides and were reflected from shimmering propeller blades above it.
"Helicopter," said Davis crisply. "Now!"
The black flyer was a thousand feet below them and still falling. The nose of the biplane dipped sharply and it dived straight for the still falling machine. Teddy gripped the machine gun and sighted along the barrel. Down, down, the biplane darted, all the power of its eight hundred horse power aiding in the speed of its fall. The glistening black machine checked in its drop and hung motionless in mid-air. The pilot was evidently unconscious of the machine swooping down upon him.
Five hundred feet down, six hundred——Teddy pulled hard on the trigger, and his machine gun spurted fire. A stream of explosive projectiles sped toward the menacing black shape. Teddy saw them strike the shining sides of the machine and explode with little bursts of flame. The biplane was rushing with incredible speed toward the other flyer. Teddy played his machine gun upon it as he might have played a hose, and apparently with as little effect. The tiny explosive shells struck and flashed futilely. The black flyer seemed to be unharmed. After a second's hesitation, it dropped again abruptly. The biplane shot toward the spot the other machine had occupied. The distance was too short to turn or swerve, quickly as it responded to the controls.
"Flares," gasped Davis, but before he spoke Teddy was pressing the small button that would set them off.
A burst of tiny lights shot out before the biplane, many-colored balls of fire driven forward from a tube below the fusilage. They illuminated the air for a short distance, entering the space from which the black flyer had just dropped. Teddy and Davis saw a small cloud of what seemed to be mist or fog hanging in the air. The tiny fire balls darted into it the fraction of a second before the biplane itself had to traverse the same space. As the first of the lights struck the fringe of the whitish cloud it flared up. The fire ball had touched a droplet of liquified gas and set it flaming. It burned fiercely and with incredible rapidity, setting fire to the remainder of the cloud. Teddy ducked his head as the aëroplane shot madly through a huge globe of blazing gas in mid-air.