In 1912 the director of the Royal Prussian Geodetic Institute in Potsdam suggested to the superintendent of the United States Coast and Geodetic Survey that the two agencies work together to make a direct connection between their respective longitude networks. The observers would use "the Bamberg or broken telescope transit which had been in use in Germany for some time," and they would communicate with each other by means of the transatlantic telegraph cable. The Americans acquired two Bamberg transits for this purpose shortly before the outbreak of war in 1914, and the cutting of the transatlantic cable. These instruments were then used for
longitude determinations within the United States, and they remained in use until 1960. The Bamberg geodetic transit at the Smithsonian is of this sort. It has a "broken" telescope that is viewed through one end of the horizontal axis, a graduated vertical circle, a cast iron base, and mechanism that is used to lift and reverse the telescope. This example may be one of the many instruments that American intelligence officers captured for the German geodetic office at the end of World War II. The National Imagery and Mapping Agency transferred it to the Smithsonian in 2000.
Carl Bamberg (1847-1892) served an apprenticeship with Carl Zeiss at Jena and studied at the Universities of Jena and Berlin before establishing a Werkstätten für Präzisions-Mechanik und Optik in Friedenau, a suburb of Berlin, in 1871. After Bamberg's death, the firm was managed by his widow, and then by his son. The firm displayed a "broken" transit in the German Educational Exhibition at the World's Fair held in St. Louis in 1904. In 1921 Bamberg merged with the Centralwerkstatte Dessau, forming a new company known as Askania Werke.
Ref: F. M. Feldhaus, Carl Bamberg, Ein Rückblick auf sein Wirken und auf die Feinmechanik (Berlin-Friedenau, 1929), p. 73.
Carl Bamberg, Astronomische und Astrophysikalische Instrument (Leipzig/Berlin, about 1920).
Fremont Morse and O. B. French, "Determination of the Difference in Longitude between Each Two of the Stations Washington, Cambridge, and Far Rockaway," United States Coast and Geodetic Survey Special Publication 35 (1916).
G. D. Cowie and E. A. Eckhardt, "Wireless Longitude," United States Coast and Geodetic Survey Special Publication 109 (1924).
A. J. Hoskinson and J. A. Duerksen, "Manual of Geodetic Astronomy,"United States Coast and Geodetic Survey Special Publication 237 (1952)