er pasturage. They might wander, but they would be safe.
With their swift heels they could defend themselves from even a mountain
lion. And they were apt to keep to the mountain meadows, where was food
and water.

Their run at such an altitude had given Pedro a touch of mountain
sickness, and he had to lie flat till his heart beat more normally and
his nose stopped bleeding.

The big 'plane carried a relay of provisions for the fire fighters
already established, whom it had brought for the purpose from the Zuni
Mine. As corned beef and hardtack were distributed, the hungry campers
thought they had never tasted anything so good in their lives. Not even
the Thanksgiving turkeys of later years were ever spiced with such
appetites.

This fire,--or rather, these three fires, so mysteriously concomitant,
the Ranger explained when the boys returned, had broken so far from any
ranch or work camp that they were hard pressed for men to fight it.

"You fellows will have a mighty important part to play for the next few
days," he assured them, "or I miss my guess."

"Hurray!" shouted Ace. "Three cheers for the U. S. Airplane Patrol!" For
he knew something of the work started at the close of the war. Following
regular daily routes, this patrol not only detects fires and follows up
campers or others who may have started them, (carelessly or otherwise),
but in times of emergency carries the fire leader from one strategic
point to another,--where as likely as not there are neither roads for him
to go in his machine, nor even horseback trails,--till he has shown the
volunteer firemen how to trench and back-fire.

They needed some one, the Ranger said, to hold the top of the next
ridge,--between which and the boys lay that inaccessible canyon it would
have taken them days to have scaled afoot. By day they were merely to
watch for flying brands. Their chief work would come at night, when the
wind would turn and blow down canyon, and they might successfully
back-fire.

The fire had started in two places on the opposite bank of the Kawa, and
in one place this side of the river, and was eating its way along the
slopes with the wind which swept them by day. It certainly looked like
the work of incendiaries.

Ace begged permission to wireless for his little Spanish 'plane, in its
hangar in Burlingame, that it might be employed in some volunteer
capacity, and Radcliffe accepted his offer.

The huge DeHaviland required all of the flat