Felix Ehrenhaft (24 April 1879 – 4 March 1952) was an

Austria Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous ...

n physicist who contributed to

atomic physics Atomic physics is the field of physics that studies atoms as an isolated system of electrons and an atomic nucleus. Atomic physics typically refers to the study of atomic structure and the interaction between atoms. It is primarily concerned wit ...

, to the measurement of

electrical charge Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...

s and to the optical properties of metal

colloid A colloid is a mixture in which one substance consisting of microscopically dispersed insoluble particles is suspended throughout another substance. Some definitions specify that the particles must be dispersed in a liquid, while others extend ...

s. He was known for his maverick and controversial style. His fearless

iconoclasm Iconoclasm (from Greek: grc, εἰκών, lit=figure, icon, translit=eikṓn, label=none + grc, κλάω, lit=to break, translit=kláō, label=none)From grc, εἰκών + κλάω, lit=image-breaking. ''Iconoclasm'' may also be consid ...

was greatly admired by

philosopher A philosopher is a person who practices or investigates philosophy. The term ''philosopher'' comes from the grc, φιλόσοφος, , translit=philosophos, meaning 'lover of wisdom'. The coining of the term has been attributed to the Greek th ...

Paul Feyerabend Paul Karl Feyerabend (; January 13, 1924 – February 11, 1994) was an Austrian-born philosopher of science best known for his work as a professor of philosophy at the University of California, Berkeley, where he worked for three decades (195 ...

. He won the Haitinger Prize of the Austrian Academy of Sciences in 1917.

Biography

Early years

Ehrenhaft was born in

Vienna en, Viennese , iso_code = AT-9 , registration_plate = W , postal_code_type = Postal code , postal_code = , timezone = CET , utc_offset = +1 , timezone_DST ...

physician A physician (American English), medical practitioner (Commonwealth English), medical doctor, or simply doctor, is a health professional who practices medicine, which is concerned with promoting, maintaining or restoring health through th ...

Leopold Ehrenhaft and Louise Eggar, the daughter of a Hungarian industrialist. Ehrenhaft earned his doctorate from the

University of Vienna The University of Vienna (german: Universität Wien) is a public research university located in Vienna, Austria. It was founded by Duke Rudolph IV in 1365 and is the oldest university in the German-speaking world. With its long and rich hi ...

in 1903, working on the

optical Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultravio ...

properties of

metal A metal (from ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electrical resistivity and conductivity, e ...

lic

s. He subsequently became assistant to

Franz S. Exner Franz Serafin Exner (24 March 1849 – 15 October 1926) was an Austrian physicist. Life Exner came from one of the most important university families of the Austrian-Hungarian empire. The same Exner family included , , Sigmund Exner, and . Exn ...

Middle years

In 1907, the reality of

atom Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons. Every solid, liquid, gas, a ...

s was still disputed but

Albert Einstein Albert Einstein ( ; ; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist, widely acknowledged to be one of the greatest and most influential physicists of all time. Einstein is best known for developing the theor ...

and

Marian Smoluchowski Marian Smoluchowski (; 28 May 1872 – 5 September 1917) was a Polish physicist who worked in the Polish territories of the Austro-Hungarian Empire. He was a pioneer of statistical physics, and an avid mountaineer. Life Born into an upper ...

had both recently given accounts of

Brownian motion Brownian motion, or pedesis (from grc, πήδησις "leaping"), is the random motion of particles suspended in a medium (a liquid or a gas). This pattern of motion typically consists of random fluctuations in a particle's position insi ...

liquid A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, it is one of the four fundamental states of matter (the others being solid, gas, ...

s, strongly supporting the atomic theory. Though

Theodor Svedberg Theodor Svedberg (30 August 1884 – 25 February 1971) was a Swedish chemist and Nobel laureate for his research on colloids and proteins using the ultracentrifuge. Svedberg was active at Uppsala University from the mid 1900s to late 1940s. ...

had made important demonstrations of

s, Ehrenhaft extended the work to make observations of particles of

silver Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...

air The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing f ...

. The greater

mean free path In physics, mean free path is the average distance over which a moving particle (such as an atom, a molecule, or a photon) travels before substantially changing its direction or energy (or, in a specific context, other properties), typically as ...

of air made for a sterner test of the reality of atoms. Ehrenhaft was awarded the

Lieben Prize The Ignaz Lieben Prize, named after the Austrian banker , is an annual Austrian award made by the Austrian Academy of Sciences to young scientists working in the fields of molecular biology, chemistry, or physics. Biography The Ignaz Lieben P ...

of the Vienna Academy of Sciences for his work. In 1908, he married

Olga Steindler Olga Ehrenhaft-Steindler (28 October 1879 – 21 December 1933) was an Austrian physicist and science teacher. In 1903, she became the first woman to earn a physics doctorate at the University of Vienna. She established the first '' Wiener Hand ...

. Ehrenhaft adapted his apparatus to measure the

elementary charge The elementary charge, usually denoted by is the electric charge carried by a single proton or, equivalently, the magnitude of the negative electric charge carried by a single electron, which has charge −1 . This elementary charge is a fundam ...

and subsequently became involved in a bitter controversy with Robert Millikan, claiming to have measured an electric charge less than that of a single

electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have n ...

, Millikan being passed over for the 1920

Nobel Prize in physics ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then " ...

owing to the unresolved nature of the debate. Controversy eventually subsided as more and more

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

s were swayed by Millikan's results but even as late as 1940, Albert Einstein wrote: Even while controversy raged on sub-electronic charges, Ehrenhaft made important and substantial contributions to

physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which ...

including the demonstration of photophoresis and other effects on the interaction of particles with

light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 t ...

. Some of these effects have subsequently been explained in terms of existing phenomena, but some still remain poorly understood. He became professor of experimental physics at Vienna in 1920 and was known as a conscientious researcher and effective lecturer though single-minded to the point of absurdity. Albert Einstein was a frequent visitor to his home. Following the

Anschluss The (, or , ), also known as the (, en, Annexation of Austria), was the annexation of the Federal State of Austria into the German Reich on 13 March 1938. The idea of an (a united Austria and Germany that would form a " Greater Germa ...

in 1938, Ehrenhaft emigrated, first to England, then to the U.S. where he became a citizen.

Later years

From the mid-1930s, Ehrenhaft's thinking started to diverge strikingly from the mainstream of physics. He observed many genuinely surprising and reproducible

physical phenomena Physical may refer to: *Physical examination In a physical examination, medical examination, or clinical examination, a medical practitioner examines a patient for any possible medical signs or symptoms of a medical condition. It generally cons ...

, usually of ultra-microscopic particles near the limits of

perception Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous syste ...

. However, he was all too willing to adopt alternate theories to explain experiments that were beset with

interactions Interaction is action that occurs between two or more objects, with broad use in philosophy and the sciences. It may refer to: Science * Interaction hypothesis, a theory of second language acquisition * Interaction (statistics) * Interactions ...

and multifactorial

cause system Causality (also referred to as causation, or cause and effect) is influence by which one Event (relativity), event, process, state, or object (''a'' ''cause'') contributes to the production of another event, process, state, or object (an ''eff ...

s. From the 1940s, Ehrenhaft's views became increasingly extreme and strident, eventually terminating his good friendship with Albert Einstein. He found it impossible to obtain either research funding or even a sympathetic hearing in the U.S. In 1946, he returned to the University of Vienna where he held again his old position until his death. He became increasingly certain that he had observed

magnetic monopole In particle physics, a magnetic monopole is a hypothetical elementary particle that is an isolated magnet with only one magnetic pole (a north pole without a south pole or vice versa). A magnetic monopole would have a net north or south "magneti ...

s, ''magnetic currents'' and ''magnetolysis'', the disassociation of liquids by

magnet A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nicke ...

s rather than

electric current An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The movi ...

as in

electrolysis In chemistry and manufacturing, electrolysis is a technique that uses direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of elements from n ...

. A review of his life work can be found in the Austrian scientific journal "Acta physica Austriaca", and in the article by Rohatschek on photophoresis (see sources below).

Publications

* Ehrenhaft, Felix: ''Das optische Verhalten der Metallkolloide und deren Teilchengröße'', 1903. * Ehrenhaft, Felix: "Über die Messung von Elektrizitätsmengen, die kleiner zu sein scheinen als die Ladung des einwertigen Wasserstoffions oder Elektrons und von dessen Vielfachen abweichen", ''Kais. Akad. Wiss. Wien, Sitzber. math.-nat. Kl.'' 119 (IIa) 815–867, 1910 * Ehrenhaft, Felix: ''Das mikromagnetische Feld'', 1926. * Ehrenhaft, Felix: "Die longitudinale und transversale Elektro- und Magnetophorese", ''Phys. Zeit''. 31, 478–485, 1930 * Ehrenhaft, Felix: "Photophoresis and the Influence upon it of Electric and Magnetic fields", ''Phil. mag''. 11 (1931),140–146 * Ehrenhaft, Felix: "Physical and Astronomical information Concerning Particles of the Order of Magnitude of the Wavelength of Light", ''Journal of the Franklin Institute'', vol 230: 381–393 (Sept. 1940) * Ehrenhaft, Felix and Banet, Leo: "Is there a true magnetism or not", ''Phil. sci''. 8 (1941), 458–462 * Ehrenhaft, Felix: "Stationary Electric and Magnetic Fields in Beams of Light", ''Nature'' 147: 25 (Jan. 4, 1941). * Ehrenhaft, Felix: "Photophoresis and Its Interpretation by Electric and Magnetic Ions", ''Journal of the Franklin Institute'', vol 233 (March 1942), pp. 235–255. * Ehrenhaft, Felix: "The Magnetic Current", ''Science'' 94: 232–233 (Sept 5, 1941). * Ehrenhaft, Felix and Banet, Leo: "The Magnetic Ion", ''Science'' 96: 228–229 (Sept. 4, 1942). * Ehrenhaft, Felix: "The Magnetic Current in Gases", ''Physical Review'' 61: 733 (1942). * Ehrenhaft, Felix: "Decomposition of Matter Through the Magnet (Magnetolysis)", ''Physical Review'' 63: 216 (1943). * Ehrenhaft, Felix: "Magnetolysis and the Electric Field Around the Magnetic Current", ''Physical Review'' 63: 461-462 (1943). * Ehrenhaft, Felix: "Further Facts Concerning the magnetic Current", ''Physical Review'' 64: 43 (1943). * Ehrenhaft, Felix: "New Experiments about the Magnetic Current", ''Physical Review'' 65: 62–63 (1944). * Ehrenhaft, Felix: "Continuation of Experiments with the Magnetic Current", ''Physical Review'' 65: 256 (1944). * Ehrenhaft, Felix: "The Decomposition of Water by the So-Called Permanent Magnet...", ''Physical Review'' 65: 287–289 (May 1944). * Ehrenhaft, Felix: "The Magnetic Current", ''Nature'' 154: 426–427 (Sept. 30, 1944) * Ehrenhaft, Felix: "On Photophoresis, the true magnetic Charge and on helical Motion of Matter in Fields" (Review of his scientific work part 1, in German), ''Acta Physica Austriaca'' 4: 461–488 (1951). * Ehrenhaft, Felix: "On Photophoresis, the true magnetic Charge and on helical Motion of Matter in Fields" (Review of his scientific work part 2, in German), ''Acta Physica Austriaca'' 5: 12–29 (1952).

Biography

Early years

Middle years

Later years

Publications

See also