n."

"Then cannot we seek the protection of the Bulgarians?"

This brought a growl from Ivan.

"Better keep as far from the Bulgarians as possible," he said in a harsh
voice. "I know something of the Bulgarians."

Hal nodded.

"Besides, we have other business," he added. "We do not want to fall into
the hands of the Bulgarians if we can possibly help it. We have a mission
to perform if it is humanly possible."

"Boom!" it was the sound of a big gun.

"The battle is on," said Hal. "Will any of you come to the roof with me?
We should be able to get a good view."

"Boom! Boom! Boom! Boom! Boom!"

The battle was on in full blast.

CHAPTER XXVI.

IN GRAVE PERIL.

Helen led the way to the roof, the others following closely. As Hal had
predicted, it was possible from this height to obtain a fair view of the
opposing armies.

To the north, as far as the eye could see, the army of King Ferdinand of
Bulgaria spread out, a mass of moving energy. Faint puffs of smoke dotted
the Bulgar line as far as the eye could see.

"Cannon!" said Hal briefly.

To the south, the Serbian line moved forward. It, too, spread out on
either side as far as the eye could reach and puffs of smoke rose
steadily, shutting out the view of the moving men.

"More cannon," said Chester.

"We seem to be safe enough for the moment," said Hal. "The shells are
passing over us. But if one side or the other should advance as far as
this house, we would be in imminent danger of being struck by shells from
the other side."

"Well, one side is bound to advance sooner or later," declared Chester;
"but I guess there is nothing for us to do but wait and watch the
progress of the battle."

"You fellows can watch all you want to," said Stubbs. "I'm going down
stairs where I won't be able to see a shell coming."

"It won't make much difference whether you are up here or down there if a
shell hits this house, Mr. Stubbs," said Chester.

"Maybe not; but I won't see it and that will help some."

Stubbs betook himself below.

"Don't know what is coming over Stubbs," said Chester. "He didn't use to
be as bad as that."

"He was when we first met him," Hal replied. "But he seemed to be getting
over it. He's worse than ever now."

From their position, those upon the roof of the house could witness
the effect of some of the great shells that were hurled into the
opposing lines. One, from the Serbians, struck squarely upon the
Bulgarian firs