"Hold down the priming-pin for a second!" yelled Matt.
He was making ready to go back to Chub's assistance, when the motor took hold in proper shape, and Chub, white and worried but mightily relieved, came gliding along.
"I'm a regular mutt in a pinch like that," said he. "Lost my head completely, and wouldn't have known the first thing to do if you hadn't yelled."
"Let 'er out again," returned Matt. "We'll leave those two scoundrels behind, now, for good and all. The main thing is to get out of rifle-range while they're leaping the gap."
Side by side the chums plunged away. Looking behind them, just before they took a turn, they saw the two horsemen swinging into the air and taking the leap safely.
"We'll lead 'em now," gloried Chub, "clear into Skull Valley, if they want to follow!"
[CHAPTER X.]
PRESCOTT.
Not again did the boys see their pursuers, and for five minutes they kept up their swift pace. When finally sure that they were safe, they slowed down their machines.