<P> Even as America's westward expansion allowed over 400 million acres (1,600,000 km2) of new land to be put under cultivation, between 1870 and 1910 the number of Americans involved in farming or farm labor dropped by a third . New farming techniques and agricultural mechanization facilitated both processes . Cyrus McCormick's reaper (invented in 1834) allowed farmers to quadruple their harvesting efficiency by replacing hand labor with a mechanical device . John Deere invented the steel plow in 1837, keeping the soil from sticking to the plow and making it easier to farm in the rich prairies of the Midwest . The harvester, self - binder, and combine allowed even greater efficiencies: wheat farmers in 1866 achieved an average yield of 9.9 bushels per acre but by 1898 yields had increased to 15.3 bushels per acre even as the total area had tripled . </P> <P> Railroads allowed harvests to reach markets more quickly and Gustavus Franklin Swift's refrigerated railroad car allowed fresh meat and fish to reach distant markets . Food distribution also became more mechanized as companies like Heinz and Campbell distributed previously perishable foods by canning and evaporation . Commercial bakeries, breweries, and meatpackers replaced locally owned operators and drove demand for raw agricultural goods . Despite increasing demand, rising production caused a drop in prices, creating substantial discontent among farmers . Organizations like The Grange and Farmers Alliance emerged to demand monetary policy that allowed for money supply expansion (as most farmers carried significant debt from planting time to harvest time), railroad regulations, and protective tariffs . </P> <P> The period between 1865 and 1920 was marked by the increasing concentration of people, political power, and economic activity in urban areas . In 1860, there were nine cities with populations over 100,000 and by 1910 there were fifty . These new large cities were not coastal port cities (like New York, Boston, and Philadelphia) but laid inland along new transportation routes (like Denver, Chicago, and Cleveland). The first twelve presidents of the United States had all been born into farming communities, but between 1865 and 1912 the Presidency was filled by men with backgrounds of representing businesses and cities . </P> <P> Industrialization and urbanization reinforced each other and urban areas became increasingly congested . As a result of unsanitary living conditions, diseases like cholera, dysentery, and typhoid fever struck urban areas with increasing frequency . Cities responded by paving streets, digging sewers, sanitizing water, constructing housing, and creating public transportation systems . </P>

Which of these jobs in colonial america involved supplying raw products