a matter of much moment.

Displaying great resourcefulness and bravery, the lads had succeeded in
escaping from Berlin in an aeroplane, as narrated in "The Boy Allies on
the Firing Line," the same in which, at the opening of this story, we
find them flying swiftly eastward.

Crack revolver shots, and having skill in the use of the sword and with
their fists, the boys had fought themselves out of many ticklish
situations. And now, free again, they were making all speed to deliver
the message from the combined leaders of two countries to Grand Duke
Nicholas, a message that would mean closer cooperation between the
Russians in the east and the British and French forces in the west.

The Russian campaign so far could hardly be called a success. True, the
first German advance into Poland, with Warsaw as its object, had been
checked, and the invader had been driven back; but the mighty legions of
the Czar of all the Russias could not be mobilized with the swiftness of
the Kaiser's troops; and, when mobilized, could not be transported to
the front with the same dispatch.

Reenforced after their first defeat in Poland, the Germans had begun a
new drive into the heart of Poland. Day after day they drew nearer and
nearer to the little capital, Warsaw--the Russians retreating before
them.

But now, within two days' march of Warsaw, the Russians held steadily,
and, try as he might, the German commander could not break through this
line of steel. Grand Duke Nicholas, commander-in-chief of the Russian
armies--who at first had been with the southern army opposing the
Austrians and advancing upon Cracow, in Galicia--had hurried north, to
take personal command in Poland.

His presence had instilled new vigor into the Russian troops, and, after
several days of defensive action, the Russian troops had at last resumed
the offensive.

It was toward this mighty army that the aeroplane that had borne the
boys through the heart of the enemy was now flying swiftly.

"Seems to me," said Hal, "that by this time we must have passed the
German lines. I guess we might as well go down a bit and have a look
around."

Accordingly the machine glided nearer the earth. The day was dark and
foggy, and at first the lads could discern nothing below but a great
blur.

They drew closer.

At that moment there came a shot from below. Hal instinctively threw
over the lever in an effort to take the craft out of harm's way.

But the machine did not