der. The latter, however, were provided with masks, and when the
enemy charged they sprang from their trenches and met them on the open
ground in hand-to-hand bayonet fighting, driving them back in panic.

Again the Austrians showered gas shells on the Serbians; then, toward
dusk, came on again, but the Serbians once more broke through the
Austrian ranks and captured many prisoners.

[Illustration: The Beginning of the German-Austro-Bulgar Campaign
against Serbia.]

But in spite of these local successes by the Serbians, the fighting
was beginning to go against them; the invaders had crossed the
frontier and could no longer be dislodged. On October 11, 1915, the
official German dispatches were able to announce that Mackensen's
forces were in possession of the Serbian banks of the Danube and the
Save between Gradishte and Shabatz, a stretch of over a hundred miles.
On the Drina too, the Austrians had been able to cross over in
several places. To all these points they hurried large bodies of
reserves to push their advantages and so continue a vigorous offensive
east, south, and west of Belgrade, in a wide, sweeping movement along
the entire front.

The main effort was made in the east, to secure possession of the
Morava Valley and its railroad. Near Semendria, Gallwitz's right wing
was in touch with Koevess's left. The plan was that they should advance
up the Morava together, each covering one side of the valley. But it
was first necessary to reduce the Serbian forts at Semendria and
Pojarevatz.

It was now two weeks since the heavy artillery had begun playing on
Semendria. By October 11, 1915, the invaders had succeeded in taking
Semendria, the garrison retiring to Pojarevatz. Here a very severe
battle was fought, but finally the Serbians were forced back, though
not without inflicting the heaviest losses that the enemy had as yet
suffered. After two days the fort was taken and the Serbians retired
to the hills beyond. Thus the invaders were now ready to begin their
advance down the Morava Valley.

But just then there came a pause in the fighting. The Serbians
observed that Gallwitz waited. What he waited for was not immediately
obvious to them. Within a few days they were to know.

CHAPTER XXXII

BULGARIA ENTERS THE WAR

The Bulgarian Government suddenly threw aside all dissimulation and
declared war on Serbia, on the pretext that the Serbians had crossed
the frontier and attacked Bulgarian troops. On