the violet, which is the highest number our eyes can detect, is
a chemical force; it works the changes on the glass plate in
photography; it transfigures the dark, cold soil into woody fibre,
green leaf, downy rose petals, luscious fruit, and far pervasive
odor; it flushes the wide acres of the prairie with grass and flowers,
fills the valleys with trees, and covers the hills with corn, a
single blade of which all the power of man could not make.

This power is also fit and able to survive. The engineer Stephenson
once asked Dr. Buckland, "What is the power that drives that train?"
pointing to one thundering by. "Well, I suppose it is one of your
big engines." "But what drives the engine?" "Oh, very likely a canny
Newcastle driver." "No, sir," said the engineer, "it is sunshine."
The doctor was too dull to take it in. Let us see if we can trace
such an evident effect to that distant cause. Ages ago the warm
sunshine, falling on the scarcely lifted hills of Pennsylvania,
caused the reedy vegetation to grow along the banks of [Page 31]
shallow seas, accumulated vast amounts of this vegetation, sunk it
beneath the sea, roofed it over with sand, compacted the sand into
rock, and changed this vegetable matter--the products of the
sunshine--into coal; and when it was ready, lifted it once more, all
garnered for the use of men, roofed over with mighty mountains. We
mine the coal, bring out the heat, raise the steam, drive the train,
so that in the ultimate analyses it is sunshine that drives the
train. These great beds of coal are nothing but condensed
sunshine--the sun's great force, through ages gone, preserved for
our use to-day. And it is so full of force that a piece of coal that
will weigh three pounds (as big as a large pair of fists) has as
much power in it as the average man puts into a day's work. Three
tons of coal will pump as much water or shovel as much sand as the