HELMHOLTZ, HERMANN VON,

born Aug. 31, 1821, Potsdam, Prussia died Sept. 8, 1894, Charlottenburg, Berlin, Ger. original name Hermann Ludwig Ferdinand Helmholtz German scientist and philosopher who made fundamental contributions to physiology, optics, electrodynamics, and meteorology. He is best-known for his statement of the law of conservation of energy. A brief account of the life and works of Hermann von Helmholtz follows; for a full biography, see Helmholtz. Helmholtz graduated from the Friedrich Wilhelm Medical Institute, Berlin, in 1843. He became professor of physiology at Knigsberg in 1849, moved to the chair of physiology at Bonn in 1855, and was made professor of anatomy and physiology at the University of Bonn three years later. In 1871 he took the chair of physics at the University of Berlin and in 1888 was appointed to the additional post of director of the Physico-Technical Institute of Berlin. Helmholtz's concern for sensory perception is indicated by his two great works, On the Sensations of Tone as a Physiological Basis for the Theory of Music (1875, translation) and Handbook of Physiological Optics (1867). Toward the end of his life he wrote on the physical meaning of the principle of least action and applied the principle to electrodynamics; he also wrote and lectured on philosophical and aesthetic problems. His position was that of an empiricist, denying the doctrine of innate ideas and holding that all knowledge is founded on experience, hereditarily transmitted or acquired. Additional reading Helmholtz' Popular Lectures on Scientific Subjects, 1st and 2nd series, trans. from German, 2 vol. (1873-81), are excellent introductions to his thought. There are two biographies of Helmholtz available in English. Leo Koenigsberger, Hermann von Helmholtz (1906, reprinted 1965; originally published in German, 3 vol., 1902-03), is often technical and sometimes difficult to understand. John Gray M'Kendrick, Hermann Ludwig Ferdinand von Helmholtz (1899), deals only with Helmholtz' medical career. A collection of Helmholtz' writings on perception is contained in Richard M. Warren and Roslyn P. Warren, Helmholtz on Perception: Its Physiology and Development (1968), with critical comments. David Cahan (ed.), Hermann von Helmholtz and the Foundations of Nineteenth-Century Science (1994), is a scholarly and technical collective work written on a rather advanced level that provides a superb view of Helmholtz' many contributions to several sciences. L. Pearce Williams