"All right," was Bob's reply. "Just let me connect the motor with this clock. You see," he explained, "I have it arranged so that when it stops the clock will stop also and we can tell how long it has run."
Several times that evening the boys ran down to the basement to see if the motor was still going, and as it was humming merrily at 10:30, they decided to go to bed and trust to the clock to tell them when it stopped.
Early the next morning they rushed to the laboratory before they were half dressed, to find the motor silent and the hands of the clock pointing to 4:35.
"Whoop," shouted Jack, as he caught sight of the face of the clock, "that's almost twelve hours, just think of it Bob. One of those cylinders will run the Sprite ten or twelve hours, and it wasn't full either."
"It's sure great," returned Bob with no less enthusiasm. "I guess we'll show the Jenkins some sailing now."
"That's what we will," agreed Jack. "Now we must get busy and fill some more of those cylinders."
CHAPTER II.
JACK TAKES A BATH.
"Come there, I say, are you going to sleep all day?"
Jack Golden was just dreaming that he had run the Sprite into a big rock and was much relieved to find that the resulting thump was nothing more serious than the bang of a pillow thrown at his head by his brother.
"Hey, cut that out," he mumbled, but half awake. "What time is it, anyway?"