these reasons, the water frame became popular and widespread. In 1771, Richard Arkwright took a lease on land in Cromford. By 1774, his first mill was operational, and in 1776 he began construction of a second mill at Cromford. During this time, he developed machines for pre-spinning and in 1775 took out his second patent. With spinning mechanised, the other processes involved in producing cotton could not keep up and also required mechanisation. He produced a machine for carding, the process which laid out the cotton fibres parallel, however not all his inventions were successful and cleaning the cotton was performed by hand until the 1790s when an effective machine was invented. Arkwright sought financial assistance, and Peter Nightingale – a local landowner (and grand uncle of Florence Nightingale) – bought the Cromford Estate for £20,000 (£ as of ). Nightingale also built Rock House as a residence for Arkwright, overlooking the mill, and gave him a further £2,000 (£) to build the second mill and £1,750 (£) for workers' housing. Between 1777 and 1783, Arkwright and his family built mills at Bakewell, Cressbrook, Rocester, and Wirksworth, spread across Derbyshire and Staffordshire. Jedediah Strutt, who was Arkwright's partner in the first Cromford Mill, built mills at Belper and Milford in 1776–1781. Thomas Evans, a landowner in Darley Abbey, bought a further in the area around Darley Abbey at a cost of £1,140 (£) and in 1782 built a cotton mill in the village. Arkwright was paid royalties by those who had copied his machines, although some people risked prosecution by engaging in piracy. The construction of Masson Mill in Matlock Bath began in 1783, instigated by Arkwright. Contemporaneous with Arkwright's expansionism was the entry of Jedediah Strutt into the cotton spinning industry. Strutt had the advantage that Arkwright had already done all the necessary experimentation with machinery, so he did not have to invest in researching new technology. He established a mill at Belper, about south of Cromford; it was probably complete in 1781. The site was expanded with the addition of a second mill in 1784. Strutt also built a mill in Milford, about south of Belper. By 1793, two further mills were added for printing and bleaching. The Strutts estimated that by 1789 they had invested £37,000 (£) in theirs mills at Belper and Milford (£26,000 at Belper and £11,000 at Milford), and had a return of £36,000