The industrial revolution began with the mechanization of the textile industry in Lancashire and Derbyshire, and the invention of the steam engine at the end of the 19th century greatly accelerated this process. Metallurgical plants and spinning and weaving mills, built next to coal mines in South Wales, northern England and the Midlands, grew like mushrooms. The mass migration of the population to new industrial centers has begun. In the first fifty years of the 19th century, Manchester and Sheffield grew four times; in Glasgow and Belfast, where shipbuilding was rapidly developing, population growth was even greater
