Excerpts from the report: The invention of farm machinery and the application of animal and later mechanical power to agriculture have brought about a great economic revolution. During the century ended in 1930 a threefold increase in production per worker in agriculture took place in the United States as a result of progress in science and invention. A century ago about three-fourths of those gainfully employed in the United States were engaged in agriculture. In 1930 less than one-fourth were so engaged ; fully three-fourths were in nonagricultural occupations. The agricultural revolution greatly facilitated the industrial and commercial revolution. Probably no factors have affected American agriculture more profoundly during the last quarter of a century than the gas engine and hard-surfaced roads. Use of the automobile and the tractor has reduced the number of horses and mules by about one-third and released probably 40,000,000 acres of cropland, and as much more pasture, for meat and milk production. This has induced vast regional shifts in crop and livestock production.