of Limehouse, London
1884 Made 30 nhp 2cyl compound steam engine for 37 grt tug built by Joseph S. Watson, Blackwall. G S de Ritter, Limehouse. [1]
1900 Walter Henry De Ritter inherited the business, which produced marine engines, general engineering plant, and the complete machinery necessary for the preparation and manufacture of tea lead[2], white lead, Edwards' air-pumps and condensing plants.
1923 Advert: 'W. H. De RITTER & CO., Ltd., ENGINEERS, THREE COLT STRET, LIMEHOUSE, E.14. ESTABLISHED 1850. On Admiralty, Air Force and War Office Lists.' [3]
A hand-operated winch by G. S. de Ritter, probably off a ship, was seen in a reclamation yard in Somerset in 2010.