Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 148,103 pages of information and 233,633 images on early companies, their products and the people who designed and built them.
of 91-93 Baker Street, London, W1 - Head Office. Electrical Works at Bollo Lane, Acton, London. Telephone: Mayfair 1570-1. Cables: "Radiotherm, Baker, London"
1898 Company established.
1922 Manufacturer of electric heating apparatus for commercial and domestic purposes, electro-medical and radiant heat apparatus for hospitals, medical institutions, nursing homes, etc.
1929 Advert in British Industries Fair Catalogue as an Optical, Scientific and Photographic Exhibit. Manufacturers of Electrical Heating, Cooking, and Special Electrical Medical Appliances, Radiators (luminous and hot-air patterns), Branding Irons, Soldering Irons, Sealing Wax Heaters, Heat Storage "Hot-Point" Irons for Laundries, Dressmakers, Tailors, etc., including the special Dowsing Cordless system. (Scientific Section - Stand No. O.27) 
Presumably later became Dowsing Co.