Berlin, Julius Springer, 1932 & 1933. 8vo. In two half cloth bindings with gilt lettering to spines. In "Zeitschrift für Physik". Vol. 78, 1932 & Vol. 83, 1933. Library stamp to free front end-paper and title-pages. A nice and clean set. (Vol. 78:) Pp. 318-339; (Vol. 83:] [Entire volumes: VII, 857 pp.; VIII, 845 pp.].
First printing of Ruska and Knoll's two seminal papers which constitute the first theoretical and practical description of an electron microscope. This invention allowed researchers for the first time to view objects as small as the diameter of an atom. Not only did the discovery have profound influence on physics, it also revolutionized biological research, as it now became possible to distinguish individual molecules. Ruska received the Nobel Prize in physics in 1986 for his discovery regarding the electron microscope, which by the Committee was described "as one of the most important innovations of the 20th century".
In 1933 the theoretical description presented in the present paper [1932] led Ruska to build a two-stage electron microscope with a resolution exceeding that of the optical microscope [described in the 1932 paper]. The technique behind it is largely built upon de Broglie's revolutionary theory regarding the wavelength of electrons.
In 1931, working closely with Knoll, Ruska built the first electron lens, an electromagnet that could focus a beam of electrons, as if it were light. Using several such lenses, he was able to construct a prototype of an electron microscope, though with only the ability to magnify a meager 17 times. Yet, he had proven that the task was possible and he continued to improve his design. By 1933, Ruska's electron microscope, termed a transmission microscope, was much more powerful. The instrument worked by passing electrons through a thin slice of the specimen to be studied, which were then deflected to a photographic film emulsion or projected onto a fluorescent screen, generating an image at high magnification. In fact, the device was capable of magnifying specimens up to 10 times more than a contemporary light microscope.
To build a commercial version of his microscope, Ruska was forced to briefly leave the academic world and delve into private industry. He joined the Siemens Company as an electrical engineer in 1937 and the company released its first marketable electron microscope, based on Ruska's design, in 1939.
The volume contains many important contributions to 20th century physics, among others:
Heisenberg, W. Über den Bau der Atomkerne. II. Pp. 156-64:
This is the second paper in a series of three which presents Heisenberg's neutron-proton model. Shortly after Chadwick discoverd the neutron in 1932, Heisenberg developed a theory suggesting that atomic nuclei are composed of protons and neutrons, this introduced the concept of the nuclear exchange force and isotopic spin. (DSB 17: p.398).
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