Steam Power · Part 2

expanded, efforts to obtain them from ever-deeper mines intensified. Flooding in mines was a serious problem. Thomas Savery ( - ) built a model steam engine called the Miner’s Friend in to drain mines. These engines worked slowly, in shallow depths, and the boiler burst under too much pressure. Another steam engine was built by Thomas Newcomen ( - ) in . This had the major defect of losing energy due to continuous cooling of the condensing cylinder. The steam engine had been used only in coal mines until James Watt ( - ) developed his machine in . Watt’s invention converted the steam engine from being a mere pump into a ‘prime mover’ capable of providing energy to power machines in factories. Backed by the wealthy manufacturer Matthew Boulton ( - ), Watt created the Soho Foundry in Birmingham in . From this foundry Watt’s steam engines were produced in steadily growing numbers. By the end of the eighteenth century, Watt’s steam engine was beginning to replace hydraulic power. After , steam engine technology was further developed with the use of lighter, stronger metals, the manufacture of more accurate machine tools and the spread of better scientific knowledge. In , British steam engines were generating more than per cent of all European horsepower. Watt’s inventions were not limited to the steam engine. He invented a chemical process for copying documents. He also created a unit of measurement based on comparing mechanical power with that of the previous universal power source, the horse. Watt’s measurement unit, horsepower, equated the ability of a horse to lift , pounds ( , kg) one foot ( . m) in one minute. Horsepower remains universally used as an index of mechanical energy. Horses turned the wheels to grind metal. The use of steam reduced the dependence on manpower and horsepower.