then later mills requiring ever more water, built and maintained their own reservoirs. In 1781 James Watt marketed a rotary-motion steam engine that could be adapted to drive all sorts of machinery, Richard Arkwright pioneered its use in his cotton mills. Possibly the first steam engine to be used in a cotton mill was a Newcomen engine which was used at Shudehill Mill in 1783 to raise water between storage ponds so it could drive a water wheel. By 1795 most similar engines around Manchester had been replaced by Boulton and Watt or Bateman and Sherratt engines. Electricity was introduced in 1877. Steam engine drove generators to provide electric lighting. By the 1890s this was common. Electricity was used to drive the mills machinery by 1906. It was generated in the engine house, and one group-drive electric motor was placed on each floor to drive the shafts. Generators were placed exterior to the mill as it was thought that they were a fire risk. Mains driven mills started about 1907. Later mills used individual electric motors to power the machinery. Transmission The early mills had a vertical shaft to take the power from the flywheel. On each floor horizontal shafts engaged with the main shaft using bevel gearing. American mills used thick leather bands instead of shafts. A new approach was to use thick cotton ropes. A rope drum was attached to the flywheel with a channel cut for each rope. The profile was such to give maximum adherence. Spinning A spinning mill opened raw cotton bales and cleaned the cotton in the blowing room. The cotton staples are carded into lap and straightened and drawn into roving which is spun using either a mule or ring frame. The yarn can be doubled and processed into thread, or prepared for weaving. Minerva Mill, Ashton-under-Lyne was designed by P. S. Stott and equipped by John Hetherington and Son, it produced 40's twists and 65 wefts. It was typical of a mill of the 1890s. Self acting mule frame (Roberts 1830) was an improvement on Crompton's Mule (1779) which derived from earlier inventions. Mules were used in the 19th century mills for the finest counts, these needed skilled workers to operate them. Ring frame (1929) developed out of the Throstle frame (19th century) an improvement on the Arkwright's Water frame. Originally rings were only suitable for coarse counts, they were lower and