Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 143,446 pages of information and 230,060 images on early companies, their products and the people who designed and built them.
of 82 Turnmill Street, London, EC1. (1921)
of Lombard Road, Morden Road, London, SW19. Telephone: Liberty 2283. Cables: "Zealdom, London". (1947)
1888 Company founded.
1921 Advert for "Repello" Clinical Thermometer and New Improved Lens Finder. 
c1930s G. H. Zeal Ltd., of Lombard Road, Merton, London SW 19 3UU of anemometers, barometers, barographs, hygrometers, hygrographs, radiation instruments, rain gauges, sunshine recorders, thermometers, thermometer screens, thermographs.
1947 Listed Exhibitor - British Industries Fair. Manufacturers of Hydrometers, Pyrometers, thermometers, Clinical, Industrial and Mechanical. (Olympia, Ground Floor, Stand No. A.1099)