Gebrüder Fromme (fl. 1884-1926), Vienna.
Gebrüder Fromme, successors to Joseph Perfler (est. 1835), by brothers Adolf and Karl Fromme in 1884 with the workshop located at Hainburgerstraße 21. In 1903 the address becomes Herbeckstraße 29. And in 1906 the address changes to Herbeckstraße 27. It is unclear if Adolf Fromme jr. took over the reins in 1927, but the company is then renamed Adolf Fromme Mechanische, Optische und Geodätische Instrumenten-Fabrik. The address given in Lehmann's in 1927 is Herbeckstraße 27. The company Adolf Fromme was still active in 1968. The company goes into liquidation around 1970.
Gebrüder Fromme plotting triangle and ruler
Triangle and ruler set by Gebrüder Fromme. The set is used for plotting coordinates. The ruler, divided into 400 metric units, is meant to be used at an angle of 45 degrees, i.e. (400/2880)/cos(45)=0.1964. The length of the vernier scale on the triangle corresponds to a distance of 260 on the ruler, i.e. (260/2880)/cos(45)=0.1277.
Both ruler and triangle are stamped with scale 1:2880. Case measures 240x87x18mm
Adolf Fromme plotting triangles
Plotting triangle set by Adolf Fromme. This set was produced after 1926.
ANNO - AustriaN Newspapers Online
Wiener Bibliothek Digital Lehmann Online
MINOW, Helmut; Historische Vermessungsinstrumente, 2nd edition 1990, p. 278.
Rudolf & August Rost 1888-1988 Festschrift, p. 24.