Hayrakes and tedders seem to have developed almost of themselves. Diligent research has failed to discover any reliable information on the invention of the hayrake, though a horserake was patented as early as 1818. Joab Center of Hudson, New York, patented a machine for turning and spreading hay in 1834. Mechanical hayloaders have greatly reduced the amount of human labor. The hay-press makes storage and transportation easier and cheaper. There are binders which cut and bind corn. An addition shocks the corn and deposits it upon the ground. The shredder and husker removes the ears, husks them, and shreds shucks, stalks, and fodder. Power shellers separate grain and cobs more 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.