 In 1856 a wealthy US entrepreneur, Henry Lee Norris, established the North British Rubber Company in the buildings of the former Castle Silk Mill alongside the Union Canal.The company's Castle Mill premises eventually covered 20 acres of land in the area and employed thousands of workers over five generations in manufacturing a variety of products from galoshes and rubber Wellington boots to solid rubber wheels for Thomson steam traction engines (after 1870), pneumatic tyres (after 1890) and hot-water bottles.The company's design for trench boots, which was officially chosen by the War Office during the Great War, led to a lucrative government contract which saw the firm supplying up to 2750 pairs a day, reaching a total of 1.2 million pairs by the end of the war.