"The Great Minneapolis Line: The Whole Season without a Hitch," 1917

American agriculture entered a "golden age" during the late nineteenth century. High market prices for wheat drove farmers to the Plains and Western states where they carved out large -- and profitable -- "bonanza" farms. Innovative machinery reduced labor costs and a competitive traction engine industry emerged. In the 1910s, to meet the needs of farmers with less acreage, these steam-powered traction engines evolved into today's iconic tractor.

"Combines" combine the major tasks of grain harvest: cutting and gathering the crop, threshing and separating the kernels from the chaff, and disposing of the straw. The Massey-Harris Model 20, introduced in 1938, culminated over 100 years of mechanical improvements. One driver operated the self-propelled machine, which reduced the need for hired help during the labor shortages of World War II.