e and tenuous air. Trees are largely condensed
air. By the magic chemistry of the sunshine and vegetable life the
tree breathes through its myriad leaves and extracts carbon to be built
into wood. Had we the same power to extract fuel from the air we need
not dig for coal.

In doing this work the power of life in the tree has to overcome many
other kinds of force. There is the power of cohesion. How it holds
the particles of stone or iron together! You can hardly break its
force with a great sledge. But the power of life in the tree, or even
grass, must master the power of cohesion and take out of the
disintegrating rock what it wants. So it must overcome the power of
chemical affinity in water and air. The substances it wants are in
other combinations, the power of which must be overcome.

Gravitation is a great power, but the thousand tons of this tree's vast
weight must be lifted and sustained in defiance of it. So for a
thousand years gravitation sees the tree rise higher and higher, till
the great lesson is taught that it is a weakling compared with the
power of life. There is not a place where one can put his finger that
there are not a dozen forces in full play, every one of which is
plastic, elastic, and ready to yield to any force that is higher. So
the tree stands, not mere lumber and cordwood, or an obstacle to be
gotten rid of by fire, but an embodiment of life unexhausted for a
thousand years. The fairy-fingered breeze plays through its myriad
harp strings. It makes wide miles of air aromatic. Animal life feeds
on the quintessence of life in its seeds. But most of all it is an
object lesson that power triumphs over lesser power, and that the
highest power has dominion over all other power.

The great power of vegetable life was shown under circumstances that
seemed the least favorable in the following experiment:

In the Agricultural College at Amherst, Mass., a squash of the yellow
Chili variety was put in harness in 1874 to see how much it would lift
by its power of growth.

[Illustration: Yellow Chili Squash in Harness.]

It was not an oak or mahogany tree, but a soft, pulpy, squashy squash
that one could poke his finger into, nourished through a soft,
succulent vine that one could mash between finger and thumb. A good
idea of the harness is given by the illustration. The squash was
confined in an open harness of iron and wood, and the amount lifted was
indicated by weights on th