Joseph Sewill was a Liverpool clock and watchmaker, the business he founded in 1800 flourishing under his control from 1853-56. His sons took over and the company went on to dominate production of precision marine instruments and chronometers for the British maritime industry, proud to be known as ‘Maker to the Admiralty’. The business closed in 2000. This late 19th or early 20th century mahogany-cased observatory regulator wall clock, inscribed ‘Sewills of Liverpool Observatory Regulator’ sold for £740 at Adam Partridge’s rooms in the city. Regulator clocks are so accurate they are used to ‘regulate’ others to ensure perfect time keeping.