Philip Danforth Armour. Philip Armour was the first person to build a modern large-scale meatpacking plant in Chicago in 1867. The Armour plant was built at 45th Street and Elizabeth Avenue immediately to the west of the Union Stockyards. This new plant employed the modern "assembly line" (or rather dis-assembly line) method of work. The mechanized process with its killing wheel and conveyors helped inspire the automobile assembly line that Henry Ford popularized in 1913.<ref>Down on the Killing Floor: Black and White Workers in Chicago's Packinghouses, 1904–1954, p. 8.</ref> For a time the Armour plant, located on a 12-acre site, was renowned as the largest factory in the world. In addition, hedging transactions by the stockyard companies were pivotal in the establishment and growth of the Chicago-based commodity exchanges and futures markets. Selling on the futures market allowed the seller to have a guaranteed price at a set time in the future. This was extremely helpful to those sellers who expected their cattle or hogs to come to market with a glut of other cattle or hogs when prices might necessarily be substantially lower than the guaranteed futures price. Following the arrival of Armour in 1867, Gustav Swift's company arrived in Chicago in 1875 and built another modern large-scale meatpacking plant at 42nd Street and South Justine Street. The Morris Company built a meatpacking plant at 42nd Street and Elizabeth Street. The Hammond Company and the Wilson Company also built meatpacking plants in the area west of the Chicago stockyards.J'Nell L. Pate, Livestock Hotels: America's Historic Stockyards, p. 161. Eventually, meatpacking byproduct manufacturing of leather, soap, fertilizer, glue (such as the large glue factory located at 44th Street and Loomis Street), pharmaceuticals, imitation ivory, gelatin, shoe polish, buttons, perfume, and violin strings prospered in the neighborhood. Additionally, there was a "Hair Factory", located at 44th Street and Ashland Avenue, which processed hair from butchered animals into saleable items. Next to the Union Stock Yards, the International Amphitheatre building was built on the west side of Halsted Street at 42nd Street in the 1930s, originally to hold the annual International Live Stock Exposition which began in 1900. It became a venue for many national conventions. Historian William Cronon concludes: Because of the Chicago packers, ranchers in Wyoming and feedlot farmers in Iowa regularly found a reliable market for their animals, and on average received better prices for the animals they sold