of the reports Dennis joined Bob in his temporary shelter.

A snarl of vexation broke from the angry Prussian at his second failure;
and, taking Bob's hand in his own, Dennis tapped out a Morse Code
sentence on the back of it with his first finger, relieved to find from
his brother's answering squeeze that Bob understood him.

"Give me that rifle," he tapped. "There might be an unused cartridge
left in the magazine, after all."

Bob supported himself on the side of the boiler, and Dennis took the
Mauser from him without noise.

He knew the barrel must be choked with earth from the use it had been
put to, but, after all, it was a chance.

_Bur-r-r-r!_ The telephone bell struck an odd, imperative note at that
moment, and Von Dussel spoke sharply.

"You hear that, you hound?" he thundered. "You Dashwoods, you! How long
have you been here?"

They knew it was only a ruse to make them betray themselves, prompted by
their enemy's keen anxiety to answer the summons, and they stood behind
the boiler perfectly still.

_Bur-r-r-r!_

"So you will not speak," snarled Von Dussel. "Very well, I am going to
answer that message. I shall have a Browning pistol in one hand and the
receiver in the other. You had better look out; you will never leave
this room alive, either of you."

Dennis, groping silently in front of him along the brick base in which
the boiler was fixed, had found a heavy screw wrench, and, repeating his
former manoeuvre, hurled it this time to the opposite end of the
engine-room.

It dropped with a loud clang; but Von Dussel was on his guard, and
before he fired he switched his light on for an instant, and Dennis
pulled the trigger of the rifle.

It was only for a second's space that Dennis saw the man with his hand
raised, and he could not repress a fierce shout of joy as a Mauser
bullet dashed the Browning pistol from Von Dussel's hand.

"Perhaps we English are not such fools, after all!" he laughed. But
when the spy's voice answered him, it was from the opposite side of the
room.

"That remains to be seen," was his reply. "I tell you, you will not
leave this place alive. The brewery is mined, and I am going to fire the
charge. Good night. I will send Madame Dashwood a field post card
to-morrow!"

In vain Dennis had pulled on the trigger while he spoke, the rifle
pointed in the direction of the voice. That cartridge had been the last
one; and as they heard the heavy door bang for the second time t