these isolated fires, watching lest some dead giant should fall
across their path. The ground smoked under their feet. Against the
background of a faint and distant roaring, which now made itself
evident, the immediate surroundings seemed very quiet. The individual
cracklings of flames were an undertone. Only once in a while a dull
heavy crash smote the air as some great tree gave up the unequal
struggle.

They passed as rapidly as they could through this stricken field. The
night had fallen, but the forest was still bright, the trail still
plain. They followed it for an hour until it had topped the lower ridge.

Then far ahead, down through the dark trunks of trees, they saw,
wavering, flickering, leaping and dying, a line of fire. In some places
it was a dozen feet high; in others it sank to within a few inches of
the ground--but nowhere could the eye discern an opening through it. A
roar and a crackling filled the air. Sparks were shooting upward in the
suction. A blast of heat rushed against Bob's cheek. All at once he
realized that a forest fire was not a widespread general conflagration,
like the burning of a city block. It was a line of battle, a ring of
flame advancing steadily. All they had passed had been negligible. Here
was the true enemy, now charging rapidly through the dry, inflammable
low growth, now creeping stealthily in the needles and among the rocks;
always making way, always gathering itself for one of its wild leaps
which should lay an entire new province under its ravaging. Somewhere on
the other side of that ring of fire were four men. They were trying to
cut a lane over which the fire could not leap.

Bob gazed at the wall of flame with some dismay.

"How we going to get through?" he asked.

"We got to find a rock outcrop somewheres up the ridge," explained Jack,
"where there'll be a break in the fire."

He turned up the side of the mountain again, leading the way. After a
time they came to an outcrop of the sort described, which, with some
difficulty and stumbling, they succeeded in crossing.

Ahead, in the darkness, showed a tiny licking little fire, only a few
inches high.

"The fire has jumped!" cried Bob.

"No, that's their backfire," Pollock corrected him.

They found this to be true. The rangers had hastily hoed and raked out a
narrow path. Over this a very small fire could not pass; but there could
be no doubt that the larger conflagration would take the slight obstacle
in i