"Give it a little more of the positive current," directed Mr. Roumann.

"Ninety miles a second," read Mark a few moments later.

"We are creeping up, but we have not yet equalled our former speed,"
spoke Mr. Henderson. The motor was fairly whining now, as if in
protest.

"One hundred and five miles," announced Jack.

"Ha! That's some better!" ejaculated the German. "I think we shall do
it." Once more he advanced the speed lever a notch.

"One hundred and thirty!" fairly shouted Mark. "We are beating all
records!"

"And we will go still farther beyond them!" cried Mr. Roumann. "Watch
the gauge, boys!"

To the last notch went the speed handle. There was a sharp crackling,
snapping sound, as if the metal of which the motor was composed was
strained to the utmost. Yet it held together.

The hand of the dial quivered. It hung on the one hundred and thirty
mark for a second, as if not wanting to leave it, and then the steel
pointer swept slowly on in a circle, past point after point.

"One hundred and thirty-five--one hundred and forty," whispered Jack,
as if afraid to speak aloud. The two professors did not look up from