Jack's first act, on arising from amid a mass of tools, into which he
had been tossed by the explosion, was to run to where Professor Roumann
lay in a semi-conscious condition. An instant later Mark slowly arose,
and made his way to where Professor Henderson was rubbing his forehead
in a dazed fashion.

"Are you hurt?" asked Mark, of his aged friend.

"I think not," answered Mr. Henderson slowly, "but I fear Mr. Roumann
is. See to him; I'm all right."

"He's breathing," cried Jack, who had bent over the German. "He isn't
dead, at any rate."

"But he may be, unless he gets attention," said Professor Henderson.
"Get my medicine chest, Mark, and we'll see what we can do for him."

Jack had raised the head of the injured man on his arm, and was giving
him some water from a glass. This partially revived the German, and he
opened his eyes. He looked around, into the faces of his friends, as if
scarcely comprehending what had happened, and then, as his gaze
wandered toward the disabled Cardite motor, he exclaimed:

"Some enemy has done this! The motor was tampered with. The resistance
block was loosened, and that caused the force of the Cardite to shoot
out at the rear. We must watch out for the work of this enemy!"

"Don't distress yourself about that now," urged Mr. Henderson. "Are you