although it had no market place, so providing food for the inhabitants was problematic. The settlement doubled in size between 1788 and 1801, and between 1801 and 1831 the population increased from 615 to 1,170 with the addition of much worker's housing. A Sunday School for 80 children was established in one of the mills and a church and school were built in 1819 and 1826 respectively. Despite being a major power of the cotton industry in the first quarter of the 19th century, the Strutts' company began to lose out to competition from Lancashire mill towns. The problem of shifting markets affected the entire Derwent Valley; Lancashire was better situated than Derbyshire in relation to the raw materials and new markets. The mills run by the Strutt family also suffered from a lack of modernisation; although they were at the forefront of fireproofing technology at the start of the 19th century, as the machines the mills used got bigger and more powerful, the Strutts persevered with child labour where adults would have been more adept at using the machinery. The company declined and in the second half of the 19th century some of its mills were leased or sold off to other companies. Although the cotton industry in the Derwent Valley declined, many of the structures associated with the industrial processes associated with producing cotton and workers' housing has survived and there are 848 listed buildings in the World Heritage Site. Transport Cromford canal The Erewash Canal, begun in 1777, was intended to primarily transport coal. It flowed from the River Trent in Sawley to Langley Mill, south of Cromford. In 1788, Richard Arkwright asked William Jessop to estimate the cost of building a canal connecting the mills at Cromford to Langley Mill. The figure Jessop came up with was £42,000 (£ as of ) which was raised within a couple of weeks. Local mill owners Jedediah Strutt and Thomas Evans opposed the proposed canal, fearing it would interfere with the water supply for their own mills, but in 1789 Parliament granted permission to construct the canal. When the Cromford Canal was opened in 1794, it had cost nearly twice Jessop's original estimate. Between Langley Mill and Cromford Wharf, where the canal terminated in the mill complex, the canal crossed two aqueducts, traversed of tunnel beneath some ironworks at Bull Bridge, and fourteen locks. Three-quarters of the cargo transported