Hermann von Helmholtz

Hermann von Helmholtz
Hermann Ludwig Ferdinand von Helmholtz
Born	August 31, 1821 Potsdam, Germany
Died	September 8, 1894 Charlottenburg, Berlin, Germany
Residence	Germany
Nationality	German
Field	Physicist and physiologist
Institutions	University of Königsberg University of Bonn University of Heidelberg University of Berlin
Alma mater	Royal Friedrich-Wilhelm Institute
Academic advisor	Johannes Peter Müller
Notable students	Albert Abraham Michelson Wilhelm Wien William James Heinrich Hertz Michael Pupin Friedrich Schottky Arthur Gordon Webster
Known for	Conservation of energy

Hermann Ludwig Ferdinand von Helmholtz (August 31, 1821 – September 8, 1894) was a German physician and physicist who made one of the first formulations of the principle of the conservation of energy. He made important contributions to many fields, including the physiology, mathematics and thermodynamics.

Early life

Helmholtz was the son of the Potsdam Gymnasium headmaster, Ferdinand Helmholtz, who had studied classical philology and philosophy, and who was a close friend of the publisher and philosopher Immanuel Hermann Fichte. Helmholtz's mother, Caroline Penn was of English extraction.

As a young man, Helmholtz did not distinguish himself in his early studies, but showed a proficiency in math and science. At age 17, he expressed an interest in physics, but economic circumstances dictated his career direction as a military doctor. He studied at the medico-surgical institute in Berlin from 1838 to 1842, where he earned his degree upon acceptance of his dissertation on the nerve cells of ganglia. He remained in that city and practiced as an army surgeon, all the while continuing his studies in physics and mathematics in his spare time.

Conservation of energy

His first important scientific achievement, an 1847 physics treatise on the conservation of energy was written in the context of his medical studies and philosophical background. He discovered the principle of conservation of energy while studying muscle metabolism. He tried to demonstrate that no energy is lost in muscle movement, motivated by the implication that there were no vital forces necessary to move a muscle.

Drawing on the earlier work of Sadi Carnot, Émile Clapeyron and James Prescott Joule, he postulated a relationship between mechanics, heat, light, electricity and magnetism by treating them all as manifestations of a single force (energy in modern terms). He published his theories in his book Über die Erhaltung der Kraft (On the Conservation of Force, 1847).

In 1848 Helmholtz became assistant of the Anatomical Museum in Berlin, and teacher of anatomy at the Academy of Arts. A year later he moved to Konigsberg to assume a professorship in physiology, where he spent the next seven years. In 1849, Helmholtz married Olga von Velten.

In 1851, Helmholtz revolutionized the field of ophthalmology with the invention of the ophthalmoscope; an instrument used to examine the inside of the human eye. This made him world famous overnight. Helmholtz's interests at that time were increasingly focused on the physiology of the senses. His main publication, entitled Handbuch der Physiologischen Optik (Handbook of Physiological Optics), provided empirical theories on spatial vision, color vision, and motion perception, and became the fundamental reference work in his field during the second half of the nineteenth century. His theory of accommodation went unchallenged until the final decade of the twentieth century.

Helmholtz became professor of anatomy and physiology at the University of Bonn in 1856. He became interested in fluid dynamics and showed that movement such as is illustrated by a smoke ring would, in a frictionless fluid, continue forever. This was expanded by William Thomson to a theory of atoms.

In 1859, Helmholtz's first wife died after a long illness; Helholtz and Olga had two children by their marriage. In 1859, he took a position as professor of physiology at the University of Heidelberg. In 1861, Helmholtz married Anna von Mohl, and the couple had two children.

Electromagnetism

In 1863 Helmholtz published a book called On the Sensations of Tone as a Physiological Basis for the Theory of Music, once again demonstrating his interest in the physics of perception. This book influenced musicologists into the twentieth century. Helmholtz invented the Helmholtz resonator to show the strength of the various tones.

In 1871, professor of natural philosophy at the University of Berlin.

In 1871 Helmholtz moved from Heidelberg to the University of Berlin where he became a professor of natural philosophy, finally fulfilling his lifelong dream. There he took up some of the problems of electromagnetic theory. His mathematical formulation in this field is known as Helmholtz's equation. Helholtz's student Heinrich Rudolf Hertz became famous as the first to demonstrate electromagnetic radiation. Hertz's discoveries were a direct result of a challenge made to him by Helmholtz to demonstrate the existence of what Maxwell had called the displacement current in air or empty space.

In 1883 Helmholtz introduced concept of free energy, the heat energy available to do work. This was an important advance in thermodynamics, and the concept is widely used in thermodynamics today.

In 1887, in addition to his teaching duties in Berlin, he became director of the physicotechnical institute in Charlottenburg. His last years were devoted to an attempt to unify the sciences under the principle of least action.

Helmholtz continued to work for several decades on editions of the handbook, frequently updating his work because of his dispute with Ewald Hering who held opposite views on spatial and color vision. Helmholtz tended to rely on experience as an important input to spatial comprehension, while Hering and the so-called "nativists" emphasized the innate intuition as playing the most important role. The philosophical dispute divided the discipline of physiology during the second half of the 1800s.

Achievements

Students and associates

Other students and research associates of Helmholtz at Berlin included Max Planck, Heinrich Kayser, Eugen Goldstein, Wilhelm Wien, Arthur König, Henry Augustus Rowland, A. A. Michelson, and Michael Pupin. Leo Koenigsberger, who studied at Berlin while Helmholtz was there, wrote the definitive biography of him in 1902.

Sensory physiology

The sensory physiology of Helmholtz was the basis of the work of Wilhelm Wundt, a student of Helmholtz, who is considered one of the founders of experimental psychology. He, more explicitly than Helmholtz, described his research as a form of empirical philosophy and as a study of the mind as something separate. Helmholtz had in his early refutal of the speculative early nineteenth century tradition of Naturphilosophie stressed the importance of materialism, and was focusing more on the unity of "mind" and body.

Ophthalmic optics

Helmholtz in front of Humboldt University in Berlin

Helmholtz extended a theory originally proposed by Thomas Young that the human eye detects and is sensitive to only three primary colors. Helmholtz proposed that each of these three colors has a particular type of receptor in the eye that detects it.

Legacy

Helmholtz's treatise on the principle of the conservation of energy was widely read and influential. He continued to make major contributions to fields as diverse as physiology, applied mathematics, electromagnetic theory, and thermodynamics. His work, particularly in the philosophy and physiology of perception, continued to exert an influence on scientists through the twentieth century. Said James Clerk Maxwell, "...he establishes principles in pure hydrodynamics which have excaped the penetrative power of all the mathematicians who preceded him, including (Joseph Louis) Lagrange himself. (Maxwell, 597).

he put great stock in the importance of meeting the best minds of his time. "When one finds himself in contact with a man of the first order, the entire scale of one's intellectual conceptions is modified for life. Contact with such a man is perhaps the most interesting thing life may have to offer." (Johannes Muller Maxwell's papers 753)

References

ISBN links support NWE through referral fees

• Maxwell, James Clerk. 2003. Hermann Ludwig Ferdinand Helmholtz in The Scientific Papers of James Clerk Maxwell, Mineola, N.Y.: Dover Publications. 1:293. ISBN 0486495604.
• Cahan, David. 1993. Hermann von Helmholtz and the foundations of nineteenth-century science. Berkeley: University of California Press. ISBN 0585112894

Bibliography

Primary:

• 1971. Selected Writings of Hermann von Helmholtz. Kahl, Russell, ed. Wesleyan Uni. Press.
• 1977. Helmholtz: Epistemological Writings. Cohen, Robert, and Wartofsky, Marx, eds. and trans. Reidel.
• Ewald, William B., ed., 1996. From Kant to Hilbert: A Source Book in the Foundations of Mathematics, 2 vols. Oxford Uni. Press.
  • 1876. "The origin and meaning of geometrical axioms," 663-88.
  • 1878. "The facts in perception," 698-726.
  • 1887. "Numbering and measuring from an epistemological viewpoint," 727-52.
• Leo Koenigsberger, translated by Frances A. Welby Hermann von Helmholtz (Dover, 1965)

Secondary:

• Cahan, D.,1993. Hermann Ludwig Ferdinand von Helmholtz and the Foundations of Nineteenth Century Science, University of California Press.

See also

• Helmholtz free energy
• Helmholtz coil which was named in his honor.
• Helmholtz resonance
• Helmholtz theorem
• Helmholtz decomposition
• Helmholtz equation
• Young-Helmholtz theory, about the trichromatic colour vision

External links

• "Hermann von Helmholtz" (Obiturary). Royal Society (Great Britain). (1854). Proceedings of the Royal Society of London. London: Printed by Taylor and Francis.
• O'Connor, John J.; Edmund F. Robertson "Hermann von Helmholtz". MacTutor History of Mathematics archive.
• On the Conservation of Force Introduction to a Series of Lectures Delivered at Carlsruhe in the Winter of 1862–1863, English translation
• Treatise on Physiological Optics 1910, three volumes. English translation by Optical Society of America (1924-5).
• Biography and bibliography in the Virtual Laboratory of the Max Planck Institute for the History of Science

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