"A nice climb," acquiesced Nat. "Now, Birdy, be good. Straight ahead. No flunking now—steady," and he "coaxed" the machine into a slow, even run, that became more and more irksome as the grade swelled.
"But when we get at the top?" asked Tavia.
"We will not stay there long," answered Nat, "for if there is one thing this machine likes to do it is to coast down hill."
The Fire-Bird made its way up the steep grade, and presently, as Nat predicted, turned the hill-crest and "flew" down the other side.
The swiftness of the motion made conversation impossible, for the machine was coasting, the power being off, and surely the Fire-Bird was "flying through the air."
Reaching the level stretch again, Nat threw in the clutch, but a grinding and clanking noise answered his movement of the lever.
"Hello!" called Ned from the rear. "Busted!"
"Something wrong," agreed Ned, looking at the spark and gasoline controllers.
Presently, as the boys expected, the machine slowed up, and then came to a stop.
Both were out at once, and they examined the mechanism together.