PURSUED BY AN ENEMY PLANE

But if the lads against whom their menace, their malice and their
machinations were directed were not aware of the activities of these
German spies and servants, the Secret Service of the United States was,
and its watchful eye was upon them–more cleverly discerning than ever
the eye of Constabule Allerson had been in following the movements and
thwarting the purposes of that agent of evil, Henryson.

And even as these Hun tools now were watching the American plane
disappear over the horizon, so two Government agents, from the secret
recesses of the long abandoned Coast Guard storehouse were observing
their every movement by the aid of two pairs of strong marine glasses.

Apparently mere curiosity-seekers and hangers-on around the scene of the
proposed Transatlantic hop-off, these two men had been constantly on
guard, and as a matter of fact, to continue the concealment of their
own identity, had apparently unconsciously dropped the tip which had
first put Captain Allerson close on the trail of the incendiary and
plane-fixer, Henryson.

So it was that within the next ten minutes one of the two, first making
certain that he was unobserved, hurriedly left the rear of their
hiding-place, leaving his companion there to continue the vigil while he
took a circuitous route and a little later, in what seemed to be the
most aimless manner, and with a vacant grin on his face like the veriest
bumpkin, strolled up to the hangar where all these hasty preparations
were going forward.

The man on the door, who gave all the evidence of merely loafing there,
but who in reality was an eagle-eyed “look-out,” saw the apparent
backwoodsman approaching and returned his grin with a scowl.

“Howdy?” the disguised Secret Service man saluted, evidencing an intent
to enter into conversation.

“Same to you; what d’you want?” the man on the door returned sharply.

“Nothin’, less you got a spare chaw on ye,” the other replied.

“Don’t chew,” came the surly reply.

“Smoke?” The agent, entirely ignoring the other’s tone and manner,
produced and offered a pouch of tobacco.

The man on the door was by this time approaching a rage. Also the other
man by this time had gained a position from which he could see almost
the entire interior of the hangar. It was as he suspected, although he
gave no evidence of even understanding what was going on within. They
were preparing for the flight!

“Look here,” said the irate look-out testily, rejecting the proffered
pouch, “I like my own tobacco best, same as I like my own company best.”

“H’m,” exclaimed the Secret Service man, vacantly, as though trying to
interpret the significance of this subtle sarcasm. “Wall,” he opined
finally, “thar’s all sorts o’ tobacco, same’s thar’s all sorts o’
comp’ny, an’ thar’s no accountin’ fer the queer tastes some people has.”

He strolled on, leaving the look-out fuming. In ten minutes he was back
giving his colleague a good laugh at what had taken place. However, they
had little time for the amusing side of their experiences, for theirs
was a serious work–as serious in its way as was that of our four
friends in another, and the efforts of all were directed toward getting
those secret and highly important documents to the Peace Conference
without molestation and before there was an open rupture there.

And all this while the crew entrusted with this important work was
cutting across the Atlantic, putting mile after mile between the
600-horsepower dual-motor hydroplane and the shores of America.

A hasty conference brought the two Secret Service men to the conclusion
that no time should be wasted in reporting to headquarters just what the
situation was. So at different times, and taking different routes, they
strolled toward the center of town, where one of them entered the
telegraph office and sent off, to a certain Henry Billings, on “F”
Street, Washington, D. C., this apparently commonplace message: “Lumber
all shipped; expect to leave here tonight.”

To Billings, otherwise the head of the Secret Service, who now was in
constant touch with members of the Cabinet, it carried a more pertinent
import, for it told him that the plane which they already had learned
might be used to pursue the Transatlantic messengers had been made
completely ready and probably would put out that evening

The Cabinet was hastily called together in special meeting, and the
summons also brought General Bronson, head of the air service. But after
all, what was there to be said? The die had been cast, so to speak, and
the lads now were far out over the ocean, with no alternative but to
continue the race at top speed to prevent a meeting with the enemy
plane, which doubtless would attack with any weapon and under any
circumstance advantageous to itself.

“There is nothing to do but to try at once to get in touch with them by
wireless,” announced General Bronson. “They are not fools, and although
nothing was said to them on this phase of the subject, they probably
realized that they were not given a machine gun to mount, with plenty of
rounds of ammunition, for nothing.”

“Wireless them, then,” ordered the Secretary of War briefly. “Give them
an outline of the exact situation.”

Long ago the men in the giant plane out over the ocean had sailed
eastward into the night. Darkness was settling about the national
capital, the streets were crowded with homeward-bound throngs of shop
and business people, as General Bronson jumped into a waiting taxicab,
and, with an abrupt order to the uniformed man at the wheel, was shot
through the city and beyond its limits, toward the great Government
wireless station, in violation of every traffic regulation that ever had
been laid down for the District of Columbia.

“R-S-7,” he fairly shouted at the operator before he was fully into the
radio room. “R-S-7, quick.”

The operator, realizing whom this call was for and that something really
urgent must be in the wind to so disturb the usually imperturbable
General Bronson, threw on his switch and began sending out through the
ether successive repetitions of the aeroplane’s code call,
“R-S-7”–“R-S-7”–“R-S-7”–“R-S-7.”

For twenty minutes this was kept up, while the perspiration stood out
upon the brow of the man who had declared upon his reputation that these
four, of all the men in the air service, were the most competent for the
fulfilling of the delicate and dangerous task which had been imposed
upon them. He paced the floor back and forth, stopping now and then by
the operator, but saying nothing.

Presently the radio man ceased tapping with the key which with every
contact seemed to release a streak of blue lightning from the
delicately tuned apparatus above their heads. He was listening intently.
Something had taken his entire attention.

“Have you got them?” General Bronson finally demanded, unable longer to
control his impatience.

“Somebody’s picked us up, and they’re trying to say something, but I
can’t catch it,” the operator at length answered, still straining to
hear the faintest and almost indistinguishable tap-taps which at
intervals came to his trained ear.

He arose abruptly and strode across the room. There he pulled a lever,
turned a switch, and then resumed his seat, hastily clapping on the
earpieces again.

His features began to relax. He reached for the sending key, then
apparently changed his mind and grasped a pencil and pad of paper. But
before he could begin to write his countenance fell, and he turned
wearily toward the anxiously waiting General.

“Had them then, I’m sure,” he said, “but lost them the next second.”

“It’s their speed,” the General asserted quickly. “Probably they can get
you all right, because you’re sending with more power. Tell them to
slow down and repeat their message.”

The operator followed these instructions, and a few seconds later looked
up smiling. Straining to catch every click recorded in his ear, he
wrote:

“Fully understand–ready for emergency–constant watch and full
speed–Bentner.”

“Ask them their position now,” the General snapped out.

[Illustration: “ASK THEM THEIR POSITION NOW!” THE GENERAL SNAPPED OUT.]

The radio operator began sending again, but there was no response, and
repeated efforts were unsuccessful.

“They’re probably pounding out for Europe at the best speed that the
craft will develop now,” the operator finally announced. “And if they
are, their spark plugs will sufficiently divert the radio to prevent
their message carrying this far.”

The General eyed him for an instant in amazement, started to say
something and then apparently changed his mind. He turned to go.

“If you hear from them again, ‘phone me instantly,” he said. “I’ll be at
my office throughout the night.”

“Yes, sir,” the operator responded respectfully, and resumed his
position at the radio.