than a hundred times as rapidly as a pair
of human hands could do. One student of agriculture has estimated that
it would require the whole agricultural population of the United States
one hundred days to shell the average corn crop by hand, but this is an
exaggeration.

The list of labor-saving machinery in agriculture is by no means
exhausted. There are clover hullers, bean and pea threshers, ensilage
cutters, manure spreaders, and dozens of others. On the dairy farm the
cream separator both increases the quantity and improves the quality of
the butter and saves time. Power also drives the churns. On many farms
cows are milked and sheep are sheared by machines and eggs are hatched
without hens.

There are, of course, thousands of farms in the country where machinery
cannot be used to advantage and where the work is still done entirely or
in part in the old ways.

Historians once were fond of marking off the story of the earth and of
men upon the earth into distinct periods fixed by definite dates. One
who attempts to look beneath the surface cannot accept this easy method
of treatment. Beneath the surface new tendencies develop long before
they demand recognition; an institution may be decaying long before its
weakness is apparent. The American Revolution began not with the Stamp
Act but at least a century earlier, as soon as the settlers realized
that there were three thousand miles of sea between England and the rude
country in which they found themselves; the Civil War began, if not
in early Virginia, with the "Dutch Man of Warre that sold us twenty
Negars," at least with Eli Whitney and his cotton gin.

Nevertheless, certain dates or short periods seem to be flowering times.
Apparently all at once a flood of invention, a change of methods, a
difference in organization, or a new psychology manifests itself. And
the decade of the Civil War does serve as a landmark to mark the passing
of one period in American life and the beginning of another; especially
in agriculture; and as agriculture is the basic industry of the country
it follows that with its mutations the whole superstructure is also
changed.

The United States which fought the Civil War was vastly different
from the United States which fronted the world at the close of
the Revolution. The scant four million people of 1790 had grown to
thirty-one and a half million. This growth had come chiefly by natural
increase, but also by immigration, conquest,