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.
"Great God!" gasped Davis. "Now where's Varrhus?"
The heavy masks the two aviators had worn had protected them from the
flaming hydrogen, and their goggles had saved their eyes. Now Davis was
only eager to make a second attempt upon the black machine. He swerved
and circled. The searchlights below were waving frantically through
the air. The flare aloft had been seen, and they concentrated upon
the space below the spot. In a second the black flyer was once more
outlined by half a dozen beams. Davis banked sharply and darted toward
it again.
The pilot of the strange machine seemed to be quite confident that he
had disposed of his antagonist, and was apparently busy with something
inside the cabin. He was probably preparing to release his cold bomb,
but was again interrupted. The biplane approached. Teddy saw his
explosive bullets strike and flash. He knew they struck, but they
seemed incapable of doing harm. The black flyer was clearly defined by
the searchlights, and Teddy could see it distinctly. It was a long,
needlelike body with a glass-inclosed cabin near the center. Above it
four whirring disks of comparatively huge size showed the position of
the vertical propellers that enabled it to rise and fall and to hang
suspended motionless in the air. A fifth propeller spun slowly at the
bow. That was evidently not running at full speed. Below the needlelike
body hung a misshapen globe, like the bulging ovipositor of some
strange insect.
Flash! Flash! The impact of the explosive bullets was marked by
spiteful cracks as they burst. Teddy was aiming for the cabin of the
machine.
"Got him!" he exclaimed.
The glass of the cabin windows had splintered into fragments. The
aëroplane shot toward the motionless black flyer.
"Shall I ram?" asked Davis in a perfectly even voice. He was quite
prepared to sacrifice both his and Teddy's lives to make absolutely
certain of the destruction of the menacing helicopter with its more
than dangerous occupant.
Teddy, with lips compressed, nodded. He had forgotten that in the
darkness Davis could not see his movement. As the biplane sped forward
the black machine dropped again. Again the whitish cloud was left
behind it, clearly defined in the searchlight rays. Teddy had barely
time to press the flare button before they reached the cloud. The mist
of atomized liquid hydrogen seemed to burst into flame all about them.
The aëroplane roared through hell-fire for a moment. Flame was before
Teddy's aviator's goggles. He was in a veritable inferno. Then the
aëroplane shot free again.
"Ram him!" panted Teddy. "Smash him! Do anything, only we've got to get
him!"
They circled swiftly, searching for the black flyer. The searchlights
were following him now, and they saw that he was rising straight up.
He had not yet dropped his cold bomb. Davis put his machine at the
ascent at as steep an angle as he dared. They climbed almost as
rapidly as the helicopter. The black machine made its first aggressive
move now. Davis was climbing in a jerky spiral, rising at an amazing
speed. Teddy was busily fitting a new belt of cartridges into his
machine gun. The pilot of the other machine darted to one side and a
huge cloud of mist sprang into being just below him, darting downward
like some pale-gray snake, unfolding itself in the sky. Davis zoomed
sharply. Another second and he would have run into the whitish cloud.
The biplane recovered and swerved to one side. Twelve thousand feet.
Thirteen thousand feet. Fourteen thousand feet. Three miles in the
air! Then the black flyer began to drop. The biplane dived after him,
Teddy's machine-gun spitting fire and explosive bullets in a furious,
well-directed blast. Once, twice, bursts of the little flashes that
showed his bullets were striking served to reassure Teddy, but the
biplane could not gain on the falling helicopter.
Down, down----There were half a dozen quick bursts of flame in the
air. Anti-aircraft guns were firing. The black flyer dropped unharmed.
Barely a thousand feet above the waters of the bay, the propeller
at the bow seemed to be put into motion, for the straight descent
changed into a graceful curve. The curve flattened out, and the black
machine ceased to fall. It sped madly for the Narrows, with a bedlam
of bursting shells all about it and the vengeful, spitting two-seater
darting after it like an avenging Nemesis. Again and again spurts of
flame against the body of the glistening helicopter showed that Teddy's
fire was well directed, but the machine shot onward in a furious rush
for the Narrows. Above the Narrows, without pausing, a black object
that turned to white in the searchlight rays fell from the misshapen
globe below the center of the black flyer's body. The thing that fell
seemed to leave a mist of fog behind it as it dropped. Then, its
mission accomplished, the dark machine fled toward the west.
Teddy and Davis, in the biplane, sped after it at the topmost speed of
which their aëroplane was capable. Teddy was nearly insane with baffled
rage and disappointment. He knew that he had failed. Another cold bomb
had been dropped in the Narrows, and any attempt to destroy it would
only result in the death of those who made the attempt.
"Faster, faster!" he pleaded to Davis. "If it gets far ahead of us
we'll lose it in the darkness."
Davis pressed his lips together and used every artifice he knew of to
increase the speed of his machine, but the glistening black body ahead
of them drew steadily farther away. At last it could barely be seen.
Then, as if in derision, a light appeared in the cabin of the black
flyer. It winked oddly. Dot-dash, dot-dash----
"He's signaling," said Davis.
Dot-dash, dot-dash----
"W-a-t-c-h," spelled Davis, "t-h-e
M-i-s-s-i-s-s-i-p-p-i.--V-a-r-r-h-u-s."
"Watch the Mississippi, Varrhus," repeated Teddy. "He's getting away!
He's getting away!"
The light ahead of them winked and disappeared. The sky was empty
except for the biplane roaring after a vanished enemy.
"He's gotten away," half sobbed Davis. "Damn him! He killed Curtiss,
and he's gotten away!"
Teddy stared into the empty night with something of Davis'
disappointment and despair.