<P> By 1783 the Watt steam engine had been fully developed into a double - acting rotative type, which meant that it could be used to directly drive the rotary machinery of a factory or mill . Both of Watt's basic engine types were commercially very successful, and by 1800, the firm Boulton & Watt had constructed 496 engines, with 164 driving reciprocating pumps, 24 serving blast furnaces, and 308 powering mill machinery; most of the engines generated from 5 to 10 hp (3.7 to 7.5 kW). </P> <P> Until about 1800 the most common pattern of steam engine was the beam engine, built as an integral part of a stone or brick engine - house, but soon various patterns of self - contained rotative engines (readily removable, but not on wheels) were developed, such as the table engine . Around the start of the 19th century, at which time the Boulton and Watt patent expired, the Cornish engineer Richard Trevithick and the American Oliver Evans began to construct higher - pressure non-condensing steam engines, exhausting against the atmosphere . High pressure yielded an engine and boiler compact enough to be used on mobile road and rail locomotives and steam boats . </P> <P> The development of machine tools, such as the engine lathe, planing, milling and shaping machines powered by these engines, enabled all the metal parts of the engines to be easily and accurately cut and in turn made it possible to build larger and more powerful engines . </P> <P> Small industrial power requirements continued to be provided by animal and human muscle until widespread electrification in the early 20th century . These included crank - powered, treadle - powered and horse - powered workshop and light industrial machinery . </P>

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