there burst from the German front the sharp roar of the
mitrailleuse. The German maxims had opened fire. The Belgians fell faster
than before.

And now the Germans were ordered to charge. Squadron upon squadron raced
over the open ground in a mad dash toward the Belgian line; and as they
charged, the rapid-fire guns of the great forts poured forth their
answer. Great holes were cut in the German columns, and men and horses
were mowed down like chaff.

And still the Germans came on.

Suddenly a fierce rifle fire broke out all along the Belgian front, even
as the rapid-firers continued to belch forth their messengers of death.
Men reeled and fell in masses. The Germans wavered, halted, then
retreated. A great shout went up from the Belgian lines.

Under the support of their own field batteries, the Germans reformed for
a second charge. As before, the defenders waited until they were close,
then poured in a deadly fire. The Germans staggered, then sprang forward.
A second volley greeted them, and a second time the Germans wavered,
halted and retreated. A third time they charged, with the same result.

All this time a long-range artillery duel was in progress, whatever
advantage there was resting with the Belgians. Shot and shell poured into
the oncoming solid ranks of the German infantry, cutting great gaps in
their ranks; but these quickly filled up again, and the Germans continued
their steady advance.

All this Hal and Chester saw, and more. For they could see, to the left,
the successful advance of the enemy, as it moved upon the town of Liege.
In vain the Belgians charged upon the advancing line and poured in shot
and shell. The Germans came on. To the right the Germans also were
pushing slowly, but surely, forward.

"It is terrible! terrible!" said Chester, with a shudder, as he watched
men fall right and left.

"Horrible!" agreed Hal. "But come. We must move. It is as Captain
Derevaux said. The Belgians will be unable to hold the town. They must
retire upon the forts; and we had better retire before them."

The boys descended from their position of vantage and made their way to
the nearest fort, which they were allowed to enter upon informing an
officer of their connection with the Belgian army, just as the Belgian
troops withdrew from their positions in front of the city and fell back
upon the forts.

Liege was left at the mercy of the Germans.

For some minutes thereafter there was a lull, as when a g