exact knowledge of how far these woods extended, or where
the break would come which should cut off the fire. The wild beasts
were speeding on down the trail, and, with the instinct of her
prairie world, she reasoned that in this direction alone must lie
safety.

The smoke grew denser and more choking. Her eyes became sore. Under
her she felt the mare stretching herself to the utmost of her gait.
She came up with many of the racing denizens of the forest, but they
did not attempt to move off the trail at her approach. They were
beyond the fear of human presence. A more terrible enemy was behind
them, pursuing with gigantic strides which demolished space with
incredible swiftness.

Every moment the air grew hotter in spite of the mare's best efforts,
and Prudence knew that the fire was gaining. Hill or dale made no
difference now. It must be on--on, or the devouring monster would be
upon them. Kitty never flagged, and with increasing speed her footing
became even more sure. A loose line, with body bent well forward to
ease the animal, Prudence did all she knew to assist her willing
companion; but for every stride the faithful mare took, she knew that
the fire was gaining many yards.

The booming had increased to a steady roar, in the midst of which the
deep, thunderous detonations came like the peals of a raging storm;
the wind rushed headlong forward, the fire bringing with it an almost
cyclonic sweep of heated air. The mighty forest giants about her bent
like reeds under the terrible force, and shrieked aloud their fears at
the coming of the devouring demon.

The mare rushed down into a wide hollow. A culvert bridged a reedy
slough. The affrighted beast raced across it. The stream of the animal
world swept on about her. She breasted the steep ascent opposite, and
Prudence was forced to draw rein. She dared not allow the horse to
race up such an incline, even though the fire were within a quarter of
a mile of her; she would have been mad to exhaust the faithful
creature, which was now her only hope. Even the poor forest creatures,
mad as they were with terror, slackened their gait.

At length the hilltop was gained, and a long descent confronted them.
Kitty showed no signs of exhaustion yet, and faced her work amidst the
rush of refugees with all her original zest. Down into the valley they
tore, for the worst of all perils was in pursuit.

The valley stretched away far into the distance; ahead, here, in this
ho