ABSTRACT
The electron microscope was on the verge of a very promising future when war broke out in 1939. The new technology seemed applicable in every fi eld in which the visualisation of sub-light microscopic structures promised to provide answers to crucial questions. In some cases, vastly overrated expectations were raised. Some accounts celebrated electron microscopy as a tool that was about to knock at the door of atomic resolution and would, on a molecular basis, eventually fulfi l the dream of early modern mechanists to visualise and make comprehensible the inner structures and mechanisms of organic and inorganic bodies alike.1 The electrical engineers Ernst Ruska (1906-1988) and Bodo von Borries (1905-1956) had been engaged on the construction of an electromagnetic electron microscope since the early 1930s, fi rst as students at the Technical University of Berlin and from 1937 onwards as employees of Siemens & Halske. The fi rst type of their customised ‘Übermikroskop’ or ‘Super Microscope’ was delivered to the IG Farben plant in Hoechst in late 1939.2
On 22 June 1938, Helmut Ruska (1908-1973) gave a talk to the Berlin Medical Society and showed the fi rst images of viruses. His talk was published jointly with his brother Ernst and Bodo von Borries.3 In a combined effort, the lecture and the publication eventually caused a public sensation that even reached as far as the political leaders of the Reich.4 Shortly afterwards, IG Farben placed an initial order for three and later four instruments. However, Siemens’ hopes of early commercial success with the electron microscope were dashed by the developing war and the appearance of competitors. In 1939, Manfred von Ardenne (19071997) had completed a high-resolution, multi-purpose electron microscope. While remaining an expensive laboratory appliance, this instrument was seen by contemporary observers as a sophisticated and innovative technical achievement. At the end of 1939, Hans Mahl (1909-1988), at the central laboratory of the Allgemeine Elektrizitäts-Gesellschaft (AEG) in Berlin, completed the construction of the fi rst super microscope with an electrostatic lens system, an instrument capable of competing with the Siemens microscope if AEG had the chance to develop their
instrument into something more solid and reliable, to reach the status of development Siemens had already achieved.5
