Between 1775 and 1800 the firm produced approximately 450 engines. It did not let other manufacturers produce engines with separate condensers, and approximately 1,000 Newcomen engines, less efficient but cheaper and not subject to the restrictions of Watt's patent, were produced in Britain during that time. Boulton boasted to James Boswell when the diarist toured Soho, "I sell here, sir, what all the world desires to have—POWER." The development of an efficient steam engine allowed large-scale industry to be developed, and the industrial city, such as Manchester became, to exist.