An Austrian Fox
The 'Fox-Kleinauto' referred to in Robin Morgan-Giles' letter (June p.641) is, undoubtedly the Austrian Fuchs (which literally translates as 'Fox'). It was produced 1922-25 by lnzerdorfer Industriewerke Hans Fuchs AG of Invalidenstrasse No 1, Wein 111, founded on the 3rd September 1920 with the object of producing motors, body parts and other metalwares. The company specialized in small engines, radiators and exhaust systems.
A four-cylinder 1180cc Kleinwagen took part in the Riederberg race on the 11th June, 1922, and a three-seater (two passengers behind the driver) was produced in following years together with a small truck able to carry 600kg.
The Fuchs is not mentioned in the original edition of Doyle, but is added (p.79) in the 1963 edition. It figures briefly in Georgano's Encyclopedia 1968 on p. 237.