badly hurt? Do you need a doctor?"

The German slowly drank the rest of the water which Jack gave him, and
then gradually arose to a standing position.

"I am all right," he said faintly, "except that I feel a trifle dizzy.
Something hit me on the head, and the fumes from the Cardite took away
my breath for a moment. I think I shall be all right soon."

"Here is the medicine chest!" exclaimed Mark, coming back into the
engine room. Mr. Henderson poured out some aromatic spirits of ammonia
into a graduated glass, added a little water, and gave it to his
fellow, inventor, who, after drinking it, declared that he felt much
better. There was a cut on his forehead, where a piece of the broken
motor had struck him, but, otherwise, he did not seem injured
externally.

As for the boys, they were only stunned, nor was Mr. Henderson more
than momentarily shocked. In a few minutes the German professor was
almost himself again.

"We must try to discover who our enemy is," he said earnestly, as he
looked over the disabled motor. "He might have blown up the whole
projectile by tampering as he did with the machinery. Had I been
testing the large, instead of the small motor, there would have been
nothing left of the _Annihilator_, or us, either. Who could have done
this? If that crazy machinist is around again----"

"I don't believe he could get here from Mars," interrupted Jack, with a
smile.