tree a long while to burn, even after it gets alight, especially
if it's a big one."

"A big forest fire, fanned by a high wind, and in the dry season,"
answered the Chief Forester, "could catch the fastest runner in a few
minutes. The flames repeatedly have been known to overtake horses on the
gallop, and where there are no other means of escape the peril is
extreme."

"But will green trees burn so fast?" the older boy queried in surprise.
"I should have thought they were so full of sap that they wouldn't burn
at all."

"The wood and foliage of coniferous trees like spruce, fir, and pine are
so full of turpentine and resin that they burn like tinder. The heat is
almost beyond the power of words to express. The fire does not seem to
burn in a steady manner, the flames just breathe upon an immense tree
and it becomes a blackened skeleton which will burn for hours.

"The actual temperature in advance of the fire is so terrific that the
woods begin to dry and to release inflammable vapors before the flames
reach them, when they flash up and add their force to the fiery
hurricane. It is almost unbelievable, too, the way a crown-fire will
jump. Huge masses of burning gas will be hurled forth on the wind and
ignite the trees two and three hundred yards distant. Fortunately, fires
of this type are not common, most of the blazes one is likely to
encounter being ground fires, which are principally harmful in that they
destroy the forest floor."

"But I should have thought," said Wilbur, "that such fires could only
get a strong hold in isolated parts where nobody lives."

"Not at all. Sometimes they begin quite close to the settlements, like
the destructive fire at Hinckley, Minnesota, in 1894, which burned
quietly for a week, and could have been put out by a couple of men
without any trouble; but sometimes they start in the far recesses of the
forest and reach their full fury very quickly. Of course, every fire,
even the famous Peshtigo fire, started as a little bit of a blaze which
either of you two boys could have put out."

"How big a fire was that, sir?" asked Fred.

"It covered an area of over two thousand square miles."

"Great Caesar!" ejaculated Wilbur after a rapid calculation, "that would
be a strip twenty miles wide and a hundred miles long."

The Chief Forester nodded.

"It wiped the town of Peshtigo entirely off the map," he said. "The
people were hemmed in, ringed by fire on every side, and out of a