Belfast was the one place on the island where the industrial revolution had permanent effect. Belfast Lough was a system of activity receiving by sea fuel and raw materials for its various industries. Cotton was spun by steam machine or water-power into mill yarn which was then taken to hand loom weavers along the River Lagan in places like Ballymacarrett and the Catholic Short Strand in east Belfast. It was calculated that, by 1811, there were 150,000 power spindles producing over 70 million lengths of yarn employing about 30,000 people. Ten hundred-ton ships brought 6,000 tonnes of coal a year to keep the mills powered. The Belfast cotton industry began to lose momentum after demand decreased at the end of the Napoleonic Wars in 1815. Then, it was discovered in Preston, England that deep-soaked flax could be made into yarn by power-spinning machine in 1825. Mulholland's Cotton Mill on York Street was accidentally burned down in 1828 and rebuilt and upgraded to spin deep-soaked flax. This mill was enormous; five stories high with three steam engines, 15,300 spindles and a 186-foot-tall chimney. The Mill would render 700 tonnes of yawn from flax each year, making a massive profit. Following their example, other flax mills were eventually built throughout Belfast. Industry made Belfast the fastest growing urban centre in the United Kingdom with the population increasing from 19,000 in 1801 to over 70,000 in 1841. By 1836, Belfast had a vibrant chamber of commerce and top-level banking network which included the Northern Bank, Ulster Bank and Belfast Bank. Though it added to the prosperity of Belfast and its surrounding areas, this mechanized production of material combined with imports from England devastated the cottage industries in Ireland who failed to compete. This would later contribute to rural families depending on the potato crop as a staple of their diet which would have disastrous results in the Great Famine of the 1840s.