sites but nearer railroads. Centralization – The cost and complexity of machinery, especially that powered by water or steam, was more than cottage industry workers could afford or had the skills to maintain. The exception was the sewing machine, which allowed putting out of sewing to continue for decades after the rise of factories. Home spinning and weaving were displaced in the years following the introduction of factory production, especially as distribution became easier. Workers and machines were brought together in a central factory complex specially designed to handle the machinery and flow of materials. Although the earliest factories were usually all under one roof, different operations might be done on different floors. (Multi-story buildings were common because they facilitated transmission of power through line shafts.) In large factories, such as Baldwin locomotive works, different processes were performed in different buildings. Foundry and blacksmith operations were normally kept in a separate building for reasons of safety, cleanliness and health. The efficiency of steam engines increases with size. Because of this, the smallest steam engines were about 2 horsepower, which was larger than needed by most workshops. Consequently until electrification in the 1910s and 1920s most workshops relied on manual power or rented space in power buildings which provided a centrally powered line shaft. Standardization and uniformity – Components were made to standard specifications, such as soles, heels and uppers for shoes themselves made to uniform sizes. Uniformity was mainly due to the precision possible from machinery, but also, quality was overseen by management. The quality of many machine operations such as sewing was superior to hand methods. Near the end of the nineteenth century metal interchangeable parts became widely used. Guarantee of supply – Factories were able to produce and distribute a steady supply of goods. Workers were paid either daily wages or for piece work, either in the form of money or some combination of money, housing, meals and goods from a company store (the truck system). Piece work presented accounting difficulties, especially as volumes increased and workers did a narrower scope of work on each piece. Piece work went out of flavor with the advent of the production line, which was designed on standard times for each operation in the sequence, and workers had to keep up with the work flow. History Antiquity In Ancient Sumer around 3000 BC, the Ancient Mesopotamian economy began to develop a version