Manufacturing of circular ceramic sewage pipes began in 1846, and was highly successful; Henry Doulton set up his own company specializing in this, Henry Doulton and Co., the first business to make these. This merged with the main business in 1854. His brother John Junior also later set up his own pipe-making business. Previously sewers were just channels made of brick, which began to leak as they aged. The 1846–1860 cholera pandemic, and the tracing by Dr John Snow of the 1854 Broad Street cholera outbreak in London to a water supply contaminated by sewage led to a huge programme of improving sewage disposal, and other forms of drainage using pipes. These and an expanding range of builder's and sanitary wares remained a bedrock of Doulton into the 20th century. Metal plumbing items such as taps and cast iron baths were added to the range later. Kitchen stonewares such as storage jars and mixing bowls, and laboratory and manufacturing ceramics, were other long-standing specialities. Further facilities were set up for making these in Paisley in Scotland, Smethwick, St Helens near Liverpool, and Rowley Regis in England, and eventually Paris.