It was a dramatic moment in history when at the Paris Exhibition of '55 a hopeless contest was waged between six sturdy workmen with the old hand flail, and threshing machines from four different countries. In the half-day test the six men threshed out by hand sixty liters of wheat; while a single American with his machine threshed 740 liters and easily beat all contestants. By the time of the civil war great saving of labor had been effected by the invention of the corn planter and the two-horse cultivator. By 1865, about 250,000 reaping machines were in use and by 1880 our country had become the greatest exporter of wheat in the world. The invention of the twine-binder made this possible, making practicable the raising of greater crops of wheat; for as Professor T. N. Carver says: "The _harvesting_ of the grain crop is the crucial point. The farmer has to ask himself, not, 'How much grain can I grow?' but, 'How much can I harvest with such help as I can get?'" By the late seventies the steam thresher was fast supplanting horse-power and a great impetus was given wheat growing when the roller process for manufacturing flour was invented. By this process better flour was made from spring wheat than had ever been produced from the winter grain, and this made Minneapolis the Flour City, in place of Rochester. In rapid succession the check-rower, permitting cross cultivation of corn, the lister, for deep plowing and planting, the weeder, the riding cultivator, the disk harrow and other kindred machines greatly helped the production of corn, our greatest crop. Cheese and butter factories and improvements in dairy methods helped to make Americans probably the largest consumers of butter in the world. The Babcock test for determining the butter fat, and the centrifugal separater for extracting the cream, were most important. _The Evolution of the Plow_ In the last quarter century the improvement on these earlier farm machines has been remarkable and elaborate. One of the most wonderful continued stories of human ingenuity is the evolution of the plow, from the historic crooked stick that merely tickled the surface of the ground (and is still used in many countries) to the steam gang-plow which tears up the earth at an astonishing pace, and thoroughly prepares the soil meanwhile. When with a gang-plow and five horses, it became possible for a man to plow five acres a day, it was supposed the acme of progress was attained. But soon steam traction was introduced on the prairies and two men were able thus to plow a dozen furrows at once and cover thirty to forty acres in a day.