Haas, Arthur Erich

(b. Brünn, Moravia [now Brno, Czechoslovakia], 30 April 1884; d. Chicago, Illinois, 20 February 1941)

physics, history of physics.

After studying physics at Vienna and Göttingen, Haas received his doctorate at Vienna in 1906 and then turned enthusiastically to the history of physics. In order to qualify as a lecturer he submitted to the Philosophy Faculty of the University of Vienna a dissertation on the history of the energy principle. His paper was the cause of considerable puzzlement to the physicists who were responsible for passing an initial judgment on it, and it was decided that he should prepare an additional work in pure physics.

In fulfilling the faculty’s assignment. Haas followed the latest publications in physics and thereby came across the unsolved problem of black-body radiation toward the end of 1909. He studied J. J. Thomson’s Electricity and Matter, the contents of which are reflections on atomic structure, while reading an essay by Wilhelm Wien in the Encyclopädie der mathematischen Wissenschaften in which the suggestion was put forth that the energy element “can be derived from a universal property of the atom.” Seizing upon this idea, Haas became the first to apply a quantum formula to the clarification of atomic structure. In the process he substituted real atoms for the more formal than physical Planck oscillators in the radiation cavity.

Haas’s quantum rule E_pot= hv agrees, for the ground state, with the condition later stated by Niels Bohr; and thus Haas obtained the correct “Bohr” radius of the hydrogen atom. But, characteristically, he wrote down only the equation solved for the action quantum, i.e., . Therefore, like Wien he considered the dimensions of the atom as fundamental, from which the action quantum can then be derived. Within a numerical factor of eight Haas also correctly derived the Rydberg constant from the action quantum h, the velocity of light c, and the fundamental magnitudes of the electron, e and m. He achieved this relation by a very formal second hypothesis, namely, that the frequency derived from his quantum rule corresponds with the constant of Balmer’s equation.

Although Haas’s theorem failed to take into account the excited states—and therefore the connection with spectroscopic data—it was nevertheless a remarkable forerunner of Bohr’s atomic theory. Yet in February 1910 Haas’s ideas were termed a “carnival joke” by Viennese physicists and only slowly found recognition.

In 1913, through the intervention of Karl Sudhoff, Haas became an associate professor of the history of science at the University of Leipzig. Sudhoff, then head of the German historians of science and medicine, had been favorably impressed by Haas’s first address at Cologne in 1908 and also managed to get him the editorship of volume V of Poggendorff. At the end of World War I Haas returned to Vienna, where he gradually turned from the history of physics to physics. In 1920 he calculated—independently of F. Wheeler Loomis and Adolf Kratzer—the correct formulas for the isotope effect in rotational spectra. After several offers of guest lectureships he finally immigrated to the United States in 1935. From 1936 until his death he was professor of physics at the University of Notre Dame.

Haas’s work in the history of physics was inspired by his interest in older as well as modern theories. (He was influenced by Mach’s and Ostwald’s interest in the history of science.) Haas possessed the “conviction that no other method is as suited as the historical for facilitating the understanding of physical principles and for clarifying and deepening the knowledge of their significance” (Die Grundgleichungen der Mechanik…, preface). His numerous books written from this point of view, often based on his lectures and addresses, are masterpieces of clear exposition which were widely disseminated and translated into many languages.

BIBLIOGRAPHY

I. Original Works. Haas’s writings include Die Entwicklungsgeschichte des Satzes von der Erhaltung der Kraft (Vienna, 1909), his Habilitationsschrift; Die Grundgleichungen der Mechanik, dargestellt auf Grund der geschichtlichen Entwicklung (Leipzig, 1914); Einfiihrllngin die theorelische Physik, 2 vols. (Leipzig, 1919–1921); and Der erste Quantenansatz für das Atom (Stuttgart, 1965), repr. of 1910 papers with extensive biography and bibliography by A. Hermann.

Among Haas’s works in the history of physics are Die Entwicklungsgeschichte des Satzes von der Erhaltung der Kraft (Vienna, 1909); Der Geist des Hellenentums in der modernen Physik (Leipzig, 1914); and “Die ältesten Beobachtungen auf dem Gebiet der Dioptrik,” in Archiv füe die Geschichte der Naturwissenschaften und der Technik, 9 (1920–1922), 108–111.

II. Secondary Literature. See A. Hermann, “Arthur Erich Haas und der erste Quantenansatz für das Atom,” in Sudhoffs Archiv für Geschichte der Medizin und der Naturwissenschaften, 49 (1965), 255–268; and Genesis of Quantum Theory (Cambridge, Mass., 1971), ch. 5.

A. Hermann