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Otto von Guericke Linus Pauling John Cockcroft Ernest Walton Ferdinand Carré
James Wimshurst Charles Chardin      

Charles Chardin



Birth date : 1850
Birthplace : ?
Go back to death : ?
Place of death : ?
Nationality : French
Profession : doctor
Charles Chardin is the inventor of a technique of electrotherapy, the vascular electro-cinésique method. This one is supposed to act on the blood circulation, the lymph, the protoplasm and the muscles of the vessels by the application of an electric tension between various areas of the body and thus to cure the diseases.
From the years 1850, the apparatuses of electrotherapy cause a true passion near the experts and of the amateurs. Enthusiastic scientists and charlatans experienced protocols of electrification which we would consider more or less eccentric today and are extremely made obtain miraculous cures.
According to Charles Chardin, all the diseases can be explained by disturbances of blood circulation and are looked after easily by an application of electricity adapted to the sensitivity of the subject, without time limit none. Contrary to other methods of electrotherapy, based for example on the application of electric shocks or strong currents, that of Chardin requires very weak currents.
To support its thesis, he claims himself of Galvani and his famous experiments carried out on the frog muscles at the end of the XVIII E century. Its method, according to him, is likely to cure any disease, by avoiding the socket of any other medicine. Moreover, he is opposed violently to any surgical act.
Implementation and results awaited
The apparatus of electrotherapy of Chardin consists of a generator of current comprising several terminals and electrodes connected by metal wire to two of these terminals. A first electrode is placed at the head of the patient and a second with the affected area. By convenience, they are of variable size to adapt to the treated zone. The current, provided by a pile, is continuous and of an intensity from 2 to 3 quarantièmes of milliamperes, adjusted according to the sensitivity of the subject by choosing the adequate terminals. The duration recommended for the processing is from 6 to 10 a.m. per night. To the patients who follow his method, Chardin promises mounts and wonders: cure of the paralysis and the epilepsy, repair of the muscular lesions after an effort, processing of the grippaux states, flatulences, asthma, fevers, rules painful, tumors, cancers, gangrene, anemia, obesity etc

Square Ferdinand



Birth date : March 10th, 1824
Birthplace : Moislains
Go back to death : January 11th, 1900
Place of death : Pommeuse
Nationality : French
Profession : engineer, inventor
Ferdinand Philippe Edouard Carré is an engineer and inventor, It made known himself like the inventor of refrigerating apparatuses intended to produce ice for the breweries and by its work in electricity, a regulator of electric light or an induction machine which bears its name, it also invented the generator of static electricity.
The major invention of Ferdinand Carré is the refrigerator with absorption, in 1859. This system uses water as absorbent and ammonia like cooling agent. It gave its name to the cycle of Square describing the process of refrigeration by absorption with two fluids and two pressure levels.

James Wimshurst



Birth date : April 13rd, 1832
Birthplace : Poplar
Go back to death : January 3rd, 1903
Place of death : Clapham
Nationality : English
Profession : Physicist
Lesson : Steabonheath House
Institutions : Institution off Electrical Engineers, member of Royal Society, Thames Ironworks, Liverpool Underwriters' Registry, Board off Trade of Lloyd' S off London, Board off Trade
Distinctions : design of the machine of Wimshurst, work on X-ray, fellow in Royal Society, member of the Company of physics of London, member of the Society Roentgen, member of Royal the Institution off Naval Architects
James Wimshurst is the creator in 1883 of the electrostatic machine with influence which bears its name: the machine of Wimshurst. It in addition showed the possibility of dispersing and of reflecting the X-rays.
Wimshurst is the son of Henry Wimshurst, after being educated in Steabonheath House in London, he becomes apprentice at Thames Ironworks until 1863. In 1865, it Marie with Clara Tribble. The same year, it is transferred to Liverpoolet starts to work at Liverpool Underwriters' Registry. In 1874, it joined off Board Trade of Lloyd' S off London. Later, in 1890, he will become off the representative of Board Trade at the time of an International Conference in Washington.
Wimshurst devotes most of its spare time to experimental work. Parallel to its work in the field of electricity, he invents a vacuum pump, a device making it possible to indicate the stability of a ship and methods to feed from the headlights in electricity from the continent. In 1878, it starts to try out the induction machines to generate electric sparks with fine scientists and of entertainment. From 1880, it is interested more in the electrostatic machines with influence. Its house located at Clapham in England is equipped with a workshop having a broad variety of tools and apparatuses making it possible to work on electric lighting. Wimshurst manufactures itself several already known electrostatic generators, like those created by William Nicholson, Ferdinand Carré or Wilhelm Holtz. Wimshurst makes many modifications to the machines of these predecessors to create what one names the machine of Holtz-Wimshurst.
Little time afterwards, it develops another machine made up of two discs turning in opposite directions of which the surface of each one comprises conducting metal sectors. Compared with its predecessors, this machine is less sensitive to the atmospheric conditions and does not require power supply. It also inspires by other scientists. In 1883, the improvements made by Wimshurst to the electrostatic generator lead the apparatus to being largely known under the name of machine of Wimshurst. In 1885, one of largest the machine of Wimshurst, exposed today to the Museum off Science and Industry of Chicago, is built in England.
In 1889, Wimshurst becomes off member of the Institution Electrical Engineers. In 1891, it describes a machine generating of the AC current with high voltage. In 1896, its machine with multiple discs, which comprises more than 8 discs, finds a new use as generator of Röntgen radii for radiography and electrotherapy. For this contribution to medical science, he is elected fellow in Royal Society in 1898. He dies in Clapham in London at the 70 years age.

Ernest Walton



Birth date : October 6th, 1903
Birthplace : Dungarvan
Go back to death : June 25th, 1995
Place of death :
Nationality : Irish
Profession : physicist
Institutions : college methodist of Belfast, Trinity College of Dublin, Cavendish laboratory of the university of Cambridge
Distinctions : Medal Hughes, Royal Society London in 1938, Nobel Prize of physics in 1951
Wire of a methodist, Ernest Walton, after his studies in a college methodist of Belfast, it starts in 1922 a double course of mathematics and experimental physics in Trinity College of Dublin, which it successfully completes into 1926/27. It receives then a research grant to work at the Cavendish laboratory of the university of Cambridge, then directed by Ernest Rutherford. After its promotion in 1931, it still remains until 1934 in Cambridge before turning over to Trinity College. It is named there in 1946 professor of experimental physics.
Walton Marie in 1934 with Freda Wilson, it also girl of Pasteur methodist, they had two wire Alan and Philip and two girls Marian and Jean. He dies on June 25th, 1995 in Belfast.
Walton worked as of his arrival in Cambridge on the acceleration of the atoms using linear accelerators and Betatron. With John Cockcroft, it developed the Cockcroft-Walton generator, with which they could show that various light elements could be disintegrated by the impact of fast protons. It was the first time that the controlled fission of the atomic nucleus was shown in experiments.
In 1951, Cockcroft and Walton receive the Nobel Prize of physics for their work of avant-garde on the transmutation of the atomic nuclei using artificially accelerated atomic particles.

John Cockcroft



Birth date : May 27th, 1897
Birthplace : Todmorden
Go back to death : September 18th, 1967
Place of death : Cambridge
Profession : physicist nuclear physicist
Institutions : university of Manchester, Metropolitan Vickers Electrical Company, Cavendish laboratory, Mond of Royal Society in Cambridge laboratory, laboratories of Montreal and Chalk River, research institute for atomic energy with Harwell, Churchill College in Cambridge
Distinctions : medal Hughes, Royal Society London in 1938, order of the British Empire in 1944, knight in 1948, Nobel Prize of physics in 1951, knight commander about the Bath in 1953, member about the Merit in 1957
John Cockcroft carries out the first years of his studies. In 1914, it starts a course of mathematics at the university of Manchester. In 1915, it is useful in artillery. After its service, it goes back to Manchester and studies electrical engineering. It carries out then two years of training to the service of Metropolitan Vickers Electrical Company, then chooses to continue its studies of mathematics, which it successfully completes in 1924. He works at the Cavendish laboratory, then directed by Ernest Rutherford. In 1934, it takes the direction of the Mond laboratory of Royal Society in Cambridge. It is named in 1939 professor and becomes, in September of the same year, temporary director of the scientific research to the ministry for the provisioning lately formed to coordinate the resources during the war. This station, it begins research on the use of the radar for air defense. It takes share with the autumn 1940 with the Tizard mission on the development of the techniques of the radar and in particular the use of the magnetron and is finally named director of the department research and development of air defense. In 1944, he becomes member of the Canadian project on atomic energy and directs the laboratories of Montreal and Chalk River. He turns over to England in 1946 to take the head of the research institute for atomic energy with Harwell. He is member in 1954 of the department of atomic energy, but fills only partly this load as from 1959, when he is named titular of a pulpit in Churchill College in Cambridge. It Marie in 1925 with Eunice Elizabeth Crabtree, of which he will have five children.
Work
Cockcroft worked at the Cavendish laboratory with Pyotr Kapitsa on the generation of more intense magnetic fields and lower temperatures. From 1928, it undertakes research with his Irish colleague Ernest Walton in the field of the acceleration of the protons. They develop the Cockcroft-Walton generator together, with cascade high voltage and as of 1932 they have enough energy to break boron and lithium atoms. In the case of lithium, they identified the result of disintegration like helium cores. Through this research, they are the bases of the development of the particle accelerators which are posed.
John Douglas Cockcroft became member of Royal Society on May 7th, 1936.
In 1951, Cockcroft and Walton receive the Nobel Prize of physics for their work of avant-garde on the transmutation of the atomic nuclei using artificially accelerated atomic particles.

Linus Pauling



Birth date : February 28th, 1901
Birthplace : Portland cement
Go back to death : August 19th, 1994
Place of death : Big On
Nationality : American
University : agricultural university of Oregon, california institute off technology
Diploma : doctor of California Institute off Technology
Profession : chemist and physicist and pacifist
Distinctions : Nobel Prize of chemistry, Nobel Prize of chemistry, Langmuir price of the scientific work
Linus Carl Pauling was a chemist and American physicist. It was one of the first quantum chemists and accepted the Nobel Prize of chemistry in 1954 for its work describing the nature of the chemical bond. It publishes in 1939 a major work the Nature of the chemical bond in which it develops the concept of hybridization of orbital atomic. Its work on the substitutes of blood plasma during the Second world war, as its research concerning sickle-shaped anemia largely influenced research in biology for second half of the XX e century. He will discover in particular the structure of the helix alpha and will miss little the discovery of the structure in double helix of the desoxyribonucleic acid (ADN). He will propose a helical structure indeed triples, structure whose improvement according to the study of the DNA by X-ray crystallography could probably have brought it to the development of the model in double helix suggested by James Dewey Watson and Francis Crick in 1953. He is one of the founders of medicine orthomoléculaire and popularized the use of the vitamin C. He dies on August 19th, 1994 of the continuations of a cancer of the prostate.
He accepted also the Nobel Prize of peace in 1962, for his countryside against the nuclear tests, becoming thus one of the two only people to have received a Nobel Prize in two different categories.
In its childhood, Linus Pauling is a voracious reader, so much so that his⁄her father one day with the local newspaper writes to ask for suggestions of books to occupy it. One of his⁄her friends, Lloyd Jeffress, has a small chemistry laboratory in its room and the small experiments undertaken in this laboratory give to Pauling the desire for becoming chemical engineer.
With the college, Pauling continuous to carry out chemistry experiments by borrowing the majority of materials and the equipment from abandoned steel-works near to the place where his⁄her grandfather works as night watchman.
Pauling fails in obtaining its diploma because of insufficient results in history of the USA. Its school will decree finally the diploma to him 45 years later, after obtaining its two Nobel Prize.
In 1917, Pauling between at the agricultural university of Oregon with Corvallis. Because of its financial needs, it must work full-time in parallel of its studies, in particular like distributer of milk, projectionist and even on a shipyard. At the conclusion of its second year, it projects to seek an use with Portland to support his mother, but the university proposes to him to carry out a teaching of quantitative analysis.
During its two last years of studies with the OAC, Pauling takes note of work of Gilbert Newton Lewis and Irving Langmuir on the electronic configuration of the atoms and the way in which they bind to form molecules. It then decides to concentrate its career of researcher on the comprehension of the relationship between the structure of the atoms constituting the matter and its physical properties and chemical, which will lead it thereafter to become one of the pioneers of a new discipline, quantum chemistry. With the OAC, it at the time of carrying out its first research while working on the effect of a magnetic field on the iron crystal orientation.
In 1922, Pauling receives its Bachelor off Science of the OAC in engineering of the processes and it off continues its studies by a doctorate in California Institute Technology with Pasadena. Its research tasks relate to the use of the diffraction of x-rays for the determination of the structure of the crystals. During its three years in Caltech, it publishes seven publications on the crystalline structure of minerals, the first among it, published in Journal off the American Chemical Society concerning the structure of the molybdénite MoS2. It receives its Ph.D. of chemistry in 1925 summa cum laude.
June 17th, 1923, Pauling marries Ava Helen Miller (1903-1981), which it met at the time of its last year to the OAC and with which it will have three wire and a girl.
Following its Ph.D., Pauling obtains a purse of the Guggenheim Foundation which enables him to travel to Europe, where it works under the direction of Arnold Sommerfeld in Munich, briefly Niels Bohr in Copenhagen meets, but fails to meet Erwin Schrödinger in Zurich, all three belonging to the founders and pioneers of quantum mechanics that Pauling on the occasion to discover during its studies with the OAC. It also on the occasion to observe one of the first studies of the connection of the hydrogen molecule by the quantum mechanics, carried out by Walter Heitler and Fritz London. Pauling devotes its two years in Europe to this work and decides to make of it the principal subject of its future research. In 1927, it returns to the USA and obtains a post of professor attending of theoretical chemistry off California Institute Technology.
Pauling begins its career in Caltech by five years very productive, by applying quantum mechanics to the study of atoms and of molecules, while continuing its crystal studies by diffraction of x-rays. In five years, it produces approximately fifty publications. In 1929, it is named associated professor, then it obtains the title/titer of professor in 1930.
During the summer 1930, Pauling accomplishes a new voyage in Europe, during which he works in particular in the institute of Arnold Sommerfeld and during which he learns the possibility of using the electrons for the studies of diffraction, in the same way that were used until there x-rays. has its return, he builds an equipment of diffraction of the electrons, helped by one of his students, L.O. Brockway and uses it to study the molecular structure of a great number of chemical substances. In 1931, American Chemical Society decrees the Langmuir price to him of the scientific work most outstanding carried out by a researcher of less than 30 years.
In 1932, Pauling introduces the concept of electronegativity. By using several properties of the molecules, in particular their dipole moment and energy necessary to break connections, it establishes a scale of electronegativity, known maintaining under the name of scale of electronegativity of Pauling, useful for the prediction of the nature of the chemical bonds and associates a value of electronegativity with the majority of the chemical elements. This same year, Pauling publishes what he regards as his most important publication, in which he develops for the first time the concept of hybridization of orbital atomic and carries out an analysis of the tetravalent character of the carbon atom. It has in particular these results in a congress during which it meets Albert Einstein.
To Caltech, Pauling binds friendship with Robert Oppenheimer, who works in Berkeley but regularly comes in Pasadena to carry out research and lesson. The two men project to make team for the study of the nature of the chemical bond: Oppenheimer would carry out mathematical calculations and Pauling would interpret the results. However this relation ends when Pauling starts to suspect Oppenheimer of being too close to his wife Ava Helen. One day that Pauling works, Oppenheimer goes to the hearth of the couple and lets escape an invitation Ava Helen for an appointment in Mexico. This one refuses but brings back the incident to her husband. This invitation related to the nonchalance of Ava Helen about the incident worries Pauling and it breaks at once its relations with Oppenheimer, then creating between them a cold which will last until the end of their lives and this although Oppenheimer will propose to him thereafter to take the head of the department chemistry of the Manhattan project what Pauling will refuse being presented in the form of pacifist.
With the beginning of the year 1930, Pauling starts to publish its work on the nature of the chemical bond, which leads to its famous book Natural He off the Chemical Bond in 1939. This book is probably one of the most important books of chemistry ever published. To give an idea of its nfluence, it is enough to notice that in the 30 years which followed its first edition in 1939, it was quoted more than 16000 times what makes of it the work generally quoted in the scientific literature. At the beginning of the XXI e century, more than sixty years after its publication, of many scientific articles still quote it. It is mainly in reward of this work that it will receive the Nobel Prize of chemistry in 1954, its research on the nature of the chemical bond and their applications to the determination of the structure of complex substances.
During its work on the nature of the chemical bond, Pauling introduces in particular the concept of hybridization of orbital atomic. Whereas the electrons in the atoms are described by orbital S, p, it shows that to describe the connections within the molecules it is preferable to build functions which are mixtures of these orbital. For example, orbital the 2p and 2s of a carbon atom can combine to form four orbital equivalent which make it possible to better describe compounds like methane, to tetrahedral geometry. In the same way, orbital the 2s can combine with two orbital 2p to form three orbital equivalent while the orbital third 2p hybrid step, which makes it possible to better describe unsaturated compounds like ethylene.
One of the other fields in which it is interested is the comprehension of the relationship between the ionic connections, in which the electrons are transferred from one atom to the other and the covalent bonds, in which the electrons are shared by the atoms. It shows that these two types of connection are actually extreme cases and that the majority of the connections are in fact an ionic mixture of connection and covalent bond. It is in this field which the concept of electronegativity which it develops is most useful: the difference in electronegativity between two atoms proves to be the most relevant size to predict the degree of ionicity of a connection.
The third subject to which Pauling in the field of the chemical bond works is the comprehension of the structure of the aromatic compounds and in particular of simplest of them, the benzene.
Until there, the best description of the structure of benzene had been made by the German chemist Friedrich Kekulé von Stradonitz. This one had described this structure like resulting from the fast transition between two structures in which the simple and double connections would be alternate, simple connections coming to take the place of the doubles and reciprocally. Pauling shows that an intermediate description between the two structures, based on quantum mechanics, is more relevant: rather than two structures of fast transition, it acts rather of the superposition of two structures. This phenomenon will be later baptized name of resonance. On a certain side, this phenomenon is similar to that of hybridization of orbital atomic, since it consists of the combination of several electronic structures: the orbital atomic ones of the various carbon atoms combine between them and form the orbital molecular ones.
In the middle of the years 1930, Pauling decides to be interested in a new scientific discipline. At the beginning of its career, it had mentioned a lack of interest for the study of the biological molecules. But developing Caltech of solid competences in biology, Pauling at the time of there côtoyer of the biologists of reputation like Thomas Hunt Morgan, Theodosius Dobzhansky, Calvin Bridges or Alfred Sturtevant and starts to be interested in the study of the biological molecules, in particular thanks to a purse of the Rockefeller foundation. Its first work in the field relates to the structure of hemoglobin. He manages to show that this structure changes when the molecule collects or loses a molecule of dioxygene. Following this result, it decides to however study in a more precise way the structure of proteins by using the diffraction of x-rays., the structure of proteins proves much more difficult to determine by this technique than that of the crystallized minerals in which it was interested previously. In the years 1930, best stereotyped x-rays of proteins were carried out by the British crystallographer William Astbury, but when Pauling tries to interpret its observations using quantum mechanics in 1937, it does not reach that point.

Otto von Guericke



Birth date : November 20th, 1602
Birthplace : Magdeburg
Go back to death : May 11th, 1686
Place of death : Hamburg
Profession : scientist, inventor, mathematician, mechanic, engineer, policy
Field : physique of the vacuum
Otto von Guericke was the mayor of Magdeburg of 1646 to 1676. He had survived the bag of the city in 1631.
He is the inventor of the air pump, ancestor of the vacuum pump, consistent in a piston, a cylinder and a valve non-return, designed to extract the air from the device to which he was connected. He studied the effects of the vacuum in many experiments: he also has thanks to this system invented the first ball with facets.
Von Guericke showed the force of the atmospheric pressure with spectacular experiments, as in 1654, at the court of Frederic Guillaume I er of Brandebourg, where it had connected two copper hemispheres 51 cm in diameter and extracts the air inside those. It attached then each hemisphere to an attachment of eight horses and showed that they were not able to separate them. When it had given the interior of the hemispheres to atmospheric pressure, they separated easily. He repeated the experiment the same year in Berlin with 24 horses.
With its experiments, Von Guericke put an end in a spectacular way to the assumption of the horror vacui, which supposed that nature hates the vacuum, which was during centuries a problem for the philosophers and the scientists. It had taken as a starting point the experiments on the fluids of Torricelli and their correct interpretation by Blaise Pascal.
Von Guericke applied the barometer to weather forecasting.
Its last work concentrated on electricity, but few of its results were preserved. He invented into 1672 the first continuous production machine tools of static electricity, the electrostatic generator produced starting from a sulfur sphere, without they not proceeding for all that a scientific knowledge of the electric phenomena.
Otto von Guericke died in Hamburg in 1683 and gave its name to the university of Magdeburg.

Pieter van Musschenbroek



Birth date : March 14th, 1692
Birthplace : Leyde
Go back to death : September 19th, 1761
Place of death : Leyde
Nationality : Netherlander
Profession : physics, medicine, astrology
Institutions : university of Utrecht, university of Duisbourg, University of state of Saint-Pétersbourg, University of Leyde
Re-elected : Leyden jar, tribometer, evaporometer
Pieter van Musschenbroek is a Dutch physicist. It contributed strongly by its lessons, its discoveries and its works to introduce in Holland experimental philosophy and the newtonianism, it left important observations on electricity, magnetism, friction and the cohesion of the solids, the capillarity, it had share with the famous experiment of the Leyden jar and imagined the pyrometer.
He exerted initially medicine, then was successively professor of philosophy, mathematics and medicine with Duisbourg, Utrecht and finally with Leyde in 1740.
He was the pupil and the friend of Willem Jacob' S Gravesande.
While Réaumur tried to improve quality of the pig iron and cast iron by testing the tensile strength of metal wire, Musschenbroek tried to directly measure the resistance of samples in the form of bars, it was necessary for him for that to implement increased tractive efforts, which it managed to do by exploiting the properties of the lever. The machine which it built is described in its Dissertationes of 1729. It measured the resistance of several stone and wood turpentines several and metal, consigning the results in its Institutiones in 1734. It highlighted the difference in resistance of materials in traction and compression. This book, translated into French in 1751, had a considerable influence on the engineers and in particular on Coulomb, which took along this book when it left on mission for Martinique. Measurements of Musschenbroek were criticized by Buffon because it used only bars of reduced section, even if it were not more of wire. Measuring the rupture of the bars in inflection, Buffon noted simply that the resistance of the wood of the same gasoline is very variable and increases approximately with the density.
Musschenbroek continued work of Amontons on friction and highlighted the influence of the surface of contact. It drew the attention to the roidor of the cords, a dangerous and paradoxical phenomenon observed aboard sailing ships on the pulleys. The Bossut abbot continued research on this problem and Coulomb proposed a formula giving an account of the observations.

Charles François de Cisternay of Fay



Birth date : September 14th, 1698
Birthplace : Paris
Go back to death : July 16th, 1739
Place of death : Paris
Nationality : French
Profession : chemist
Institution : Academy of Science
Wire and grandson of soldier, François of Fay followed initially the family way and fought in the regiment of Picardy to the head offices of Saint-Sebastien and Fontarabie, gaining the rank of captain. But since 1723, it turned to the natural science and obtained a load of assistant in the class of chemistry of the Academy of Science. He was a prolific contributor of the Stories of the Academy, in particular studying phosphorescence and electrification by friction. Its qualities of experimenter at this point were recognized that it was charged by his colleagues with developing chemical tests for the quality control of the dyeings.
Louis XV named in 1732 the young chemist first intendant of the Botanical garden. According to Fontenelle, Of Fay made this establishment, neglected before him, the most beautiful garden of Europe. It accompanied the cardinal by Rohan to Rome, where it took the taste of antiquities, was accepted in 1733 member boarder of the Academy of Science and left the following year on mission to England with other academicians to study the force of wood there.
as from 1733, it was devoted primarily to the botany and the optical properties of the crystals, particularly the birefringence of the rock crystal and the Iceland spar.
François of Fay contracted the small pox with the whole beginning of July 1739 and was carried in a few days. Its succession, taken by Buffon in the general intendance of the Garden of Roy, was from the discussed start, because much of academicians expected that Duhamel of the Heap obtained this office.
Of Fay wrote almost exclusively in the memories belonging to the six sections of geometry, astronomy, mechanics, anatomy, chemistry and botany, of the Academy of Science. It started by studying the thermal phenomena in the mobility of the observations of Guillaume Amontons on the propagation of the heating one.
Informed by the councils of a German glazier, it highlighted the causes of the phenomenon of disappearance of the light in the mercury barometers that Bernoulli had observed about 1700 and who hold with the introduction of air and impurities mixed with mercury into the capillary out of glass. This explanation, which put a term at the concept of luminous barometer, was worth with of Fay its nomination like assistant of the academy.
But it is by its assumption of the two electric fluids that its name passed to the posterity.
Of Fay had indeed noted that :
Objects rubbed against of amber are pushed back.
As well as objects rubbed against a rod of glass.
But that the objects rubbed with amber attract those rubbed with glass.
It also showed that the electrification of the end of a wet cord transmits almost instantaneously to the other the end, when well even this one would be very long.
Taking again the observations of érasme Bartholin and Christiaan Huygens on the double refraction of the Iceland spar, of Fay tried to improve measurement of the angles of the second refraction, showing in particular that the cut crystals with right angles present a simple refraction and that in the other cases, the angle of the second refraction depends on the angle of the faces of the crystal.

Henry Cavendish



Birth date : October 10th, 1731
Birthplace : Nice
Go back to death : February 24th, 1810
Place of death : London
Nationality : English
Profession : chemist, physicist
Institution : Peterhouse College of Cambridge
Distinction : Copley medal
Second wire of Lord Charles Cavendish, duke of Devonshire and Lady Anne Grey, girl of the duke of Kent, Henry Cavendish is a very timid man and of a morbid sensitivity, which inspires to him the horror of the company and the marriage.
He leaves in 1753 Peterhouse College Cambridge without any diploma. There were however very able Masters, of which John Lawson. Like junior by a fortunate family, it lays out with the very modest departure only of one inheritance, but in 1773 it inherits one of his uncles an immense fortune carried out in the Indies. It becomes thus suddenly richest of all the scientists and can acquire with its expenses a cabinet of physics and an immense library. For the remainder, he saw way rather Spartan and, in spite of a great generosity towards the students and the unhappy ones, his fortune will do nothing but grow until its death.
Cavendish is one of the founders of chemistry, because it introduced into this science of the unknown work methods before him. In 1766, it presents in front of the Royal Company of London, from which he became member, a first report entitled One Factitious Airs. It there establishes the existence of gas other than the air and shows that hydrogen that it isolated the first, weighs ten times less than the atmospheric air. It still shows there that the carbonic gas weighs half more and that the presence of this last in the atmosphere in considerable quantity is enough to prevent combustions and to cause death.
In 1783, it makes an analysis of the air more precise than that of Lavoisier and the following year, it recognizes that water is the product of the combination of hydrogen and oxygen. In 1785, it combines nitrogen and oxygen while making pass through a mixture of these gases of the electric sparks.
At the same time, Cavendish makes experiments of physics. It is interested closely and contributes to the development of sciences incipient from electricity and the magnetism, inspired in these matters by the work of John Michel. In 1798, it publishes a report where it explains how it measured, by means of its torsion balance, the constant of gravitation of Newton and how it deduced the average density of the Earth from it.
In fact, the articles published of alive sound are rare, but it leaves with its death a score of packages of manuscripts, which remain during sixty years in the files of the Cavendish family. Later, another Cavendish will found in Cambridge a physics laboratory which will become famous and enjoys still now a very great international reputation. Its first director, James Clerk Maxwell, will spend the last years of his life to decipher and publish this work on a purely posthumous basis. And Cavendish will suddenly seem the largest physicist of its time.
Before everyone, it defined the specific heat and the latent heats and had the idea of the conservation of energy. Before Charles-Augustin Coulomb he studied the electrostatic forces, observed the surface electrification of the drivers, defined the capacity and had a presentiment of the concept of potential. Before Georg Ohm it conceived electrical resistance; it even took measurements by using its own body like galvanometer.
It was, with the eyes of its contemporaries, completely eccentric refusing to speak or to even see the women. It communicated with its maidservants only using paper and threatened them to lay off them if they tried to see it. It always wore the same clothes and was useful during 30 years of the same hat. Refusing to let itself paint, there does not exist any official portrait of him and the only representations are drafts carried out during dinners. The features of its personality are in agreement with a syndrome To sprinkle.

Davy Humphry



Birth date : December 17th, 1778
Birthplace : Cornouailles
Go back to death : May 29th, 1829
Place of death : Geneva
Nationality : English
Profession : chemistry, physicist
Institution : Pneumatic Institution of Bristol-board
Decoration : Copley medal, Rumford Medal, Royal Medal, Davy Medal
Sir Humphry Davy is a physicist and British chemist.
It isolated sodium, potassium, barium, strontium and calcium thanks to electrolysis in 1807 and 1808. He is also the inventor of the lamp of safety to metal cloth for the minors, known as Davy lamp, for the prevention of explosions due to the firedamp or coal dust.
Davy was born in Penzance in Cornouailles on December 17th, 1778. The register of the parish church of Madron notes : Davy Humphry, wire of Davy Robert, baptized with Penzance on January 22nd, 1779. Robert Davy was a wood-carver in Penzance and exerted his art for the pleasure more than for the profit. Resulting from an old family, he became owner of a modest inheritance. His wife, Grace Millet, belonged to a rich and old family, but which had undergone reverses of fortune. The parents of the latter died in a few hours of interval of a bad fever and Grace and his/her two sisters were adopted by John Tonkin, an eminent surgeon of Penzance. Davy Robert and his wife were the parents of five children, two boys, Humphry, the elder one and Jean, as well as three girls. During childhood the Davy one, the family left Penzance for Varfell, a hamlet of the commune of Ludgvan. The young boy partly spent his time with his parents and partly with Tonkin, which placed it in a preparatory school held by certain Mr. Bushell, but this last was so highly struck by progress of the young boy whom he persuaded his father to send to a school of a higher level. Still young person, Davy was registered with the college of Penzance, was then entrusted to the reverend J.C. Coryton. Many anecdotes show that Davy was an early boy, endowed with a remarkable memory and singularly rapid to acquire knowledge in the books. He was in particular attracted by The Pilgrim' S Progress and rained himself to read the history of it. He was hardly eight years old that he joined together around him on the place of the Market a certain number of young boys and, upright on a carriage, spoke to them about the last reading which he had made. Of this distant area it liked the folklore as much as it became, like it says it to us itself, a storyteller of stories. The applause of my comrades, says us it, rewarded me for the punishments which my idleness was worth me. Such circumstances developed at his place the love of poetry and passion to compose of the worms and the ballades.
It is in same time that at his place the taste of the applied sciences developed. It owed it mainly with a member of the Company of the friends named Robert Dunkin, saddler, man with the spirit the original and being interested in the most varied things. For itself Dunkin had built an electric machine, voltaic piles and Leyden jars and had manufactured models to illustrate the principles of mechanics. using these apparatuses, he taught in Davy the rudiments of science. As a professor at Royal the Institution, Davy repeated many clever experiments that its Master Quaker had learned to him. Leaving the school of Penzance Davy went in 1793 in Truro and finished its studies under the cane of the rev. Dr. Cardew, which wrote, in a letter with Davies Gilbert : I was not able to distinguish faculties by which it was to then be characterized so much. Davy said itself : I regard as a chance for me that one left me much with myself when I was child and that no particular study plan was imposed to me… What I am, I became it by myself.
After the death of the father the Davy one, in 1794, Tonkin made enter the young boy in training at John Bingham Borlase, a surgeon of Penzance which had vast customers. The apprenticeship contract is dated on February 10th, 1795. It is in the dispensary of the pharmacist that Davy became chemist and an attic in the house of Tonkin was the theater of its first chemical operations. The friends the Davy one often repeated : this Humphry young person is incorrigible. He will do all to us to fly in the air and his/her older sister complained about the damage that corrosive substances made on its dresses.
One told much on Davy as a poet and John Ayrton Paris says a little too quickly that its worms carry the mark of a higher genius. The first work which was preserved to us carries the date of 1795. It has as a title Wire of Genius and is marked by the usual lack of maturity of youth. The poems produced in the years which followed, especially One the Mount' S Bay and St Michael' S Mount, are pleasant descriptive worms, which show sensitivity, but no true poetic imagination. Davy poetry for science gave up well quickly. at the seventeen years age, at the same time as he wrote worms in the honor of its first love, he discussed passionately with his friend Quaker on the problem the materiality heat. Dunkin made one day this note : : I then to ensure you, Humphry, that as regards discussion you are the largest quibbler whom I ever met during my life. By one day of winter it sometimes happened to him to lead Dunkin to the Larigan river, to show him that the friction of two ice floes released by its movement a sufficient energy to dissolve them but that, if the movement were stopped, the pieces froze again and met again. It was, in a rudimentary form, the starter of a similar experiment that Davy was to realize later in the conference room of Royal the Institution and who caused a considerable attention.
Having seen by chance with Penzance the Davy young person balancing itself négligemment with a half door of the house of Dr. Borlase, Davies Giddy spoke with him and, interested by its conversation, proposed to him to use its library and invited it at his place in Tredrea. That enabled him to be presented to Dr. Edwards, who resided then at Hayle Copper House and also made conferences on chemistry at the school of St Bartholomew' S Hospital. This last authorized Davy to use the apparatus of its laboratory and it seems that he drew his attention to the locks of the port of Hayle which were degraded quickly because of the contact of copper and iron under the influence of sea water. Galvanization yet was not known, but the phenomenon prepared the spirit of Davy thereafter for its experiments on the copper coating of the ships. Gregory Watt, the son of James Watt, who remained in Penzance for health reasons and placed at Mrs. Davy, became the friend of his son and courses of chemistry gave him. Davy also made a useful knowledge, that of Wedgwood, which spent one winter to Penzance.
Dr. Thomas Beddoes and professor Hailstone were in full geological discussion on the merits of the two rival assumptions of the plutonism and the neptunism. Together they went on a journey to examine the coast of Cornouailles in company of Davies Gilbert and thus they became acquainted with Davy. Beddoes, which had recently set up at Bristol a Pneumatic Institution, needed an assistant to direct the laboratory. Gilbert recommended Davy for the station and, in 1798, Gregory Watt showed in Beddoes research of the young man on heat and the light which it published thereafter in the first volume of West-Country Contributions. It had there long discussions held especially by Gilbert. Mrs. Davy and Borlase granted the beginning the Davy one, but Tonkin would have wished to install it in its birthplace as surgeon, it changed intention however when it had noted that Davy wished to accompany Dr. Beddoes.
The Davy October 2nd, 1798 joined Pneumatic Institution of Bristol-board, created with an aim of studying the medical capacities of the atmospheres and of gases created artificially and it is with him that the supervision of the various experiments was entrusted. The agreement concluded between Dr. Beddoes and Davy was extremely generous, so much so that Davy was able to give up in favor of his/her mother any claim on her paternal heritage. It did not intend to give up becoming doctor and was still determined to make its studies and to take its ranks in Edinburgh. It launched out vigorously in work of laboratory and began a long friendship with Mrs. Anna Beddoes which was used to him as guide for its excursions and announced to him what there was of interesting in the locality. During its stay with Bristol, Davy became acquainted with the count de Durham, who for health reasons had become a member resident of Pneumatic Institution, as well as Samuel Taylor Coleridge and of Robert Southey. Davy in December 1799 went to London for the first time and its circle of relations extended notably to it.
The same year was published the first volume of West-Country Collections. Half of volume was composed of tests the Davy one : One Heat, Light, and the Combinations off Light, One Phos-oxygen and its Combinations and Theory off Breathing. The Davy February 22nd, 1799 declared in a letter with Davies Gilbert : I am now as convinced of the inanity of the theory of heating as I am to it existence of the light. In another letter of April 10th, he wrote to him : Yesterday, I made a discovery which proves how much it is necessary to repeat the experiments. The gas nitrogen oxide is perfectly respirable when it is pure. It is never harmful, whereas it is about a nitrogenized gas. I found a means of making it pure. He added whereas he had breathed of them sixteen quarters during nearly seven minutes and he completely enivré me. During this year Davy published its Researches, Chemical and Philosophical, chiefly concerning Nitrous Oxide and its Respiration. Years later Davy regretted having one day published these premature assumptions, which it qualified itself thereafter dreams of genius badly employed that the light of the experiment and observation led forever to the truth.
Initially placed in a pharmacist, it made, early, some discoveries, was destined for London where it successfully gave lessons of chemistry to the royal institution created by Rumford and was then charged to teach the application of chemistry to agriculture. It became in 1803 member of the royal Company of London and into 1820 president of this company.
as from 1810, it carries out many conferences trying out the physiological action of certain gases, in particular the laughing gas. following an accident wounding it with the left eye, he engages the young person Michael Faraday as assistant, with whom he will effectura of many scientific voyages.
Royal Society decreed the Copley medal to him in 1805, then the Rumford Medal in 1816. He was prize winner in 1827 of Royal Medal. The Davy Medal, created by Royal Society in 1877, was thus named in its honor.
It was made knight on April 9th, 1812.
One owes him several important discoveries, inter alia those of the euphoriant properties of the nitrogen protoxide synthesized by Joseph Priestley, of the true nature of the chlorine, which one wrongly looked at like a compound, formation of the acids without oxygen, finally that of the decomposition of the grounds by the galvanic pile : it is using this new and so powerful means of electrochemical analysis that it could isolate potassium, sodium, calcium, magnesium.
The lamp of safety, named on its behalf, said Davy lamp
One also owes him of research on employment like mechanical force of gases brought in the liquid state, on the doubling of the vessels and finally the invention of a lamp of safety for the minors.

Luigi Galvani



Birth date : September 9th, 1737
Birthplace : Bologna
Go back to death : December 4th, 1798
Place of death : Bologna
Profession : physicist and doctor
Institution : University of Bologna, institute of sciences
Luigi Galvani, resulting from an easy family of Bologna, is very early directed worms of the studies of medicine and philosophy. It is interested particularly in the anatomy, taught at the university of Bologna as of the XVIII E century. Its thesis of doctorate, De Ossis, constant in 1762, relates to the human skeleton. The first years of its career are divided between medical and surgical practice, anatomical research and teaching. Its public demonstrations proceed in the famous anatomical theater of the Palate of Archiginnasio. It reaches the rank of professor of anatomy and surgery at the University of Bologna in 1773. In 1782 he is elected professor of obstetrics at the institute of sciences.
In 1762, he marries Lucia, only daughter of his Master Domenico Galeazzi, anatomist of reputation. Lucia collaborates actively in work of her husband. The death of this loved wife, in 1790, is the first of misfortunes which obscure the last years of the life of Galvani. In 1797, Galvani refuses to lend oath of allegiance to the Republic cisalpine that Bonaparte has just created in Italy of north. It then loses its university stations, its wages and its residence. He dies a little later in 1798.
Many work of Galvani, those which had the greatest repercussion relate to animal electricity. The long controversy which follows with Alessandro Volta led to the invention, by this last, of the pile.
Following the discovery of the Leyden jar, whose discharges cause strong muscular contractions, the question of the possible action of the electric fluid about the alive bodies arouses a great interest. While electricians healers experienced on the man, the anatomists, such Caldani in Bologna since 1756, apply electricity to various parts of corpses of animals.
At the end of the years 1770 Galvani is interested in its turn with the influence of electricity. One will thus not be astonished to find in his laboratory an electrostatic machine, Leyden jars and frogs prepared in the usual way, i.e. by preserving only the lower extremities, with their cruraux nerves. It observes, like others before him, the sharp contractions of the thighs when electricity is directly applied to the nerve.
But here is that an observation, mentioned in its notes of 1781, causes its astonishment. Whereas the scalpel of one of its assistants touches the nerve of a frog, the thigh contracts violently at the time when a spark spouts out of the machine, located at good distance. Sheer coincidence, Galvani, helped of his Lucia wife and her nephew Giovanni Aldini, vary the conditions of the experiment : the spark starts a muscular contraction indeed remotely provided that the nerve is prolonged by a sufficiently long driver, this phenomenon will be included/understood only at the end of the XIX E century : the driver constitutes an antenna for the electromagnetic radiation emitted at the time of the spark.
The flash of a storm is a discharge of electricity of comparable nature that the spark of the machines, like showed it Benjamin Franklin. Can it cause the same effect as the spark of an electric machine? wonders Galvani. One day of storm, it installs frogs prepared on its terrace. The experiment is conclusive : each time a flash spouted out, the muscles underwent at the same time of many and violent contractions.
But a new unforeseen phenomenon appears : even in calm weather, of the contractions occur when the copper hook fixed in the spinal-cord of frog comes in contact with the bars from iron from the balcony. That seems without relationship with the electric states of the atmosphere notes Galvani. To check this point, it goes down again in its laboratory and multiplies the experiments. The thigh contracts each time nerve and muscle are connected one to the other by a formed arc of two different metals.
Galvani then formulates the assumption of an animal electricity, which would be secreted by the brain and would discharge when nerve and muscle are connected by metals.
It is only in 1791, when he thinks of having accumulated enough evidence in favor of this assumption, that Galvani publishes, in Latin, the results of ten years of tough and scrupulous experimentation : Comment on the electric forces in the muscular movement.
When it reads viribus, Alessandro Volta is already a famous physicist. Initially skeptic, it hastens to repeat the experiments of Galvani. He ignites : the discovery of Galvani is for him one of most beautiful and more surprising, and the germ of several others. But if it adheres initially to the idea of an organic electricity of origin, its doubts appear quickly. with the end of the year 1792, after having tested not only on frog but also on whole animals, its own language or its eyes, it rejects the assumption of animal electricity. Its experiments convinced it of the crucial role of the metallic arc : for him, the organic fabrics play only one passive part, and it is the contact of two different metals which puts moving electricity.
It is the beginning of a scientific war between galvanists and voltaïstes, which is spread soon in all Europe and continues after the death of Galvani. Each experiment of the ones causes an against-experiment of the others. Galvani and its partisans in particular manage to obtain contractions without any metal, for example by putting in contact the nerve with the outside of the muscle.
It is while seeking to increase the produced electric tensions believes it by the contact of two different metals that Volta is brought to the stacking of discs of zinc, money and paperboard soaked with salt water which constitutes its famous pile. The success resounding of the pile will put an end to the controversy. It is thus an instrument, and not a theory, which puts an end to it. It is necessary to wait, about thirty year later, the pioneers of electrophysiology such Carlo Matteucci to give to the honor the assumptions of Galvani on animal electricity, qualified founders by the famous German physiologist Emil of Wood-Reymond.

Stephen Gray



Birth date : December 26th, 1666
Birthplace : Canterbury
Go back to death : February 7th, 1736
Place of death : London
Profession : dyer, astronomer, physicist
Institution : Trinity college, Cambridge
Stephen Gray is the first to have systematically tested with electric conduction rather than only to examine the generation and the effect of static heads.
Gray is born in Canterbury in Kent. After a brief education, he becomes the apprentice of his father then of his older brother as dyer. However its interest goes on the natural history, in particular on astronomy and he educates himself as an autodidact in these emergent sciences at that time. For this task it is mainly helped by easy friends in Kent which give him access to their libraries and their scientific instruments. at that time science was mainly a rich person pastime.
It manufactures its own lenses and a telescope. With this instrument, it makes a good number of minor discoveries, mainly in the field of the sunspots. It thus gains a good reputation for the precision of its observations. Some of its results are published by Royal Society thanks to the mediation of a friend, Henry Hunt, who works with the secretariat of this learned society.
This work draws the attention of John Flamsteed the 1st royal astronomer who is building the new observatory of Greenwich. Flamsteed is creating a chart detailed and precise stars with the hope which it solves the problem of the determination of longitude for the sailors. Gray assistance with a good number of observations and calculations for which it was undoubtedly not paid.
Gray and Flamsteed become friends and correspond regularly and this seems to have created problems with Gray in its meaning by the scientific world. Flamsteed is then engaged in an argument prolonged with Isaac Newton on the access to the preliminary data of the chart of Flamsteed. This quarrel turned in a war of factions inside Royal Society in which Newton left victorious virtually excluding Flamsteed and its friends during several decades.
Gray works on the second astronomical observatory in Cambridge but it is so badly managed by the friends of Newton which the project fails not leaving of alternative to Gray only turn over to its trade of dyeing. However its health is problematic and soon it goes to London to assist Dr. John Theophilus Desaguliers, a member of Royal Society which gives readings in Great Britain and on the continent to present the new scientific discoveries. Gray is probably not paid but receives the lodging and cover.
Poverty occurs for Gray. Thanks to the efforts of John Flamsteed and to sir Hans Sloane it obtains a pension with Charterhouse in London, a house for people desilvered having served Great Britain. at that time, it begins its experiments on static electricity by using a tube out of glass.
One night, in its room with Charterhouse, it notes that cork at the end of its tube protecting it from moisture and dust generates a gravitational attraction on small pieces of papers and bits of straws when the tube was rubbed. When it extends its experiment with a piece of wood planted in cork the load is obvious at the end of wood with more strength than cork. It tests with longer needles and finally adds a long wire finished by an ivory ball. In this process he discovers that the virtue electricity can move and that the ivory ball attracts the light objects just like the tube out of glass.
Gray modifies its experiment to use metal wire coppers some like various materials : wood, plants green and dry, stone, teapot and discover that these materials them also lead the electric fluid. The following day he manages to transmit electricity up to 25 meters. All these tests until proceeded there vertically for probably practical reasons, it tests with horizontal but its first attempt fails. He concludes correctly that the electric fluid is dissipated by the supports of its assembly.
He then decides to try experiments on a greater height, a vertical assembly starting from the cupola of the Saint-Paul Cathedral but before that he will see his friend Granville Wheler who has a large ideal house for his tests. After having carried out successfully several experiments, Wheler suggests a horizontal assembly. Gray explains its failure to him. Wheler proposes to use silk wire to suspend conducting wire. Gray answers him I says to him that would function better being given the smoothness of the support thus there would be less fluid escaping from the line of communication. During same the few days, he visits fortunate friends (close relations of Flamsteed) and with their assistance manages to extend his experiment on more than 250 meters.
Gray and Wheler discover the importance thus to isolate their assemblies from the ground by using silk. They also note that the transport of the electric fluid does not seem not facilitated by gravity while dropping the wire since a tower.
From these experiments are born a comprehension from the part played by the drivers and insulators. Charles DuFay, a French scientist, visits Gray and Wheler in 1732, sees the experiment and after its return in France to formulate a theory called theory of the two fluids is the first. It is used by its associate the Nollet abbot and is opposed somewhat to that later of Benjamin Franklin and his group in Philadelphia. Franklin and the British experimenters Beavis and Watson study a theory using a fluid and two states that Watson names +ve and - ve which ends up prevailing on that of DuFay.
Gray continues to test, including the electric polarization of suspended objects, one often credits it with the experiment of the flying boy, a child suspended by silk wire and attracting bits of straws and other menus objects with its hands. It probably carried out years before Franklin that the flashes are due to the same phenomenon as the electric fluid.
When Hans Sloane becomes president of Royal Society, after the death of Isaac Newton, Gray receives the public recognition which was denied to him. He is the first to receive the Copley medal in 1731 for his work on conductivity then in 1732 for those on electrostatic induction. The same year he is elected member of Royal Society.
He continues to work until on his bed of dead on February 15th, 1736, where he describes with the doctor come to visit it work remaining to him to achieve.
The only known publications of Gray are addressed letters is with friends or Royal Society in which it describes some of its results. The majority of its letters are preserved nowadays in the files of Royal Society.

Mohamed Mohamedi


Birth date : February 29th, 1964
Birthplace : Algiers
Go back to death : always alive
Place of death : none
Profession : professor and researcher in electrochemistry, micro systems energy, nanomateriaux, nanostructures
Diploma : DEA and Doctorate in electrochemistry
University : Scientific national research institute of Quebec, Polytechnic National school of Algiers, Institut National Polytechnique of Grenoble, University of Trondheim, Tohoku University, Waseda University
Professor Mohamedi is interested in the energy microsystems, development of new concepts of miniature combustible batteries (<0.02 microphone-structured cm²). This field calls upon electromechanical technologies microsystems (MEMS) combined with methods microphone ⁄ nano electrochemistry. This type of piles apply to : microsensors, MEMS without wire, sources of microphone-power for medical apparatuses, etc passive Microphone-piles with fuel (10~30 cm2) Air ⁄ Alcohol. These piles use the oxygen contained in the atmospheric air and the alcohol solution is stored in a built-in tank. This type of piles is intended for portable electronics.

Charles Proteus Steinmetz

Birth date: April 9th, 1865
Birthplace: Breslau
Go back to death: October 26th, 1923
Place of death: Schenectady
Profession: mathematician, engineer
University: University of Wroclaw
Steinmetz was reached of kyphosis and a congenital luxation of the hip, just like its father and his grandfather before him.
Charles Proteus Steinmetz, supported the development of the alternative course which made possible the expansion of industry electric to the United States, formulating mathematical theories for the engineers. He made revolutionary discoveries in the comprehension of the hysteresis which made it possible to the engineers to design better electrical motors for industry.
Graduate of the room of gym with the honors, it entered to the university of Breslau in 1883. There, it joined a socialist club of the student, who was prohibited by the government after being affiliated with social democrat German. When some of his/her comrades of party were stopped, Steinmetz took again the direction of the body of the party, the voice of the people. One of the articles which it has writing was considered inflammatory, the police force began a repression on paper and Steinmetz had to flee Breslau. After a short stay in Zurich, he emigrates in the United States in 1889, travelling by the tween deck. He quickly obtained an employment in an electric small company held by Rudolf Eickemeyer in Yonkers.
Under the supervision of its employer, Steinmetz was absorbed more and more in the practical aspects of electronic engineering. It created a small laboratory with the factory, where it did much of its scientific research. Expériences Steinmetz on the losses of power in magnetic materials used in the electric machines led to its first important work, the law of hysteresis. This milked law of the loss of power which occurs in all the electricals appliance when the magnetic action is converted into unusable heat. Until this time, the losses of power in the engines, the generators, the transformers and other machines with electrical motor could be known only after they were built. Once Steinmetz had found the law governing the losses hysteresis, the engineers can calculate and minimize the losses of electrical energy because of magnetism in their designs before beginning the construction of these machines.
Its second contribution was a practical method to make calculations relating to alternative course circuits. This method is an example of the use of the mathematical assistances for the engineering of the design of machines and electric lines, so that the performance of the electric system could be predicted in advance without the need for passing by the expensive and dubious process of the construction of the system initially, then to test for its effectiveness. Steinmetz developed a method of calculating symbolic system of the phenomena of alternative course and by doing this simplified a field extremely complex and little included/understood so that average engineering could function in alternative course. This realization was largely responsible for the speed of progress in the commercial introduction of apparatus in alternative course.
Its third contribution was the study of the lightning, it manufactured a tower placed in a football field to collect that Ci and in studied the phenomenon.

Daniel McFarlan Moore



Birth date : February 27th, 1869
Birthplace : Northumberland
Go back to death : June 15th, 1936
Place of death : East Orange
Profession : engineer, inventor
University : University of Lehigh
Daniel McFarlan Moore was a U.S. electrical engineer and inventor. He developed a novel light source, the Moore lamp, and a business that produced them in the early 1900s. The Moore lamp was the first commercially viable light-source based on gas discharges instead of incandescence, it was the predecessor to contemporary neon lighting and fluorescent lighting. In his later career Moore developed a miniature neon lamp that was extensively used in electronic displays, as well as vacuum tubes that were used in early television systems.
Career
He began his career in 1890 working in the engineering department of the United Edison Manufacturing Company. At some point he started experimenting with producing light from glow discharges, which Heinrich Geissler had first developed in the 1850s. What’s wrong with my light, Thomas Edison is said to have asked when he learned that Moore had started to tinker with light-producing tubes of gas as a potential replacement for the incandescent bulb. Moore is reported to have replied undiplomatically, It’s too small, too hot and too red. Moore left in 1894 to form his own companies, the Moore Electric Company and the Moore Light Company.
The Moore lamp
Moore had devised his glow discharge lighting system by 1896. The Moore Lamp was an extension of the well-known Geissler tube, which used glass tubes from which the air had been removed and a different gas inserted. The low-pressure gas glows when a current was passed through it. As described in 1915, In the Moore system of lighting the essential feature is the introduction of a special valve which automatically admits gas into the tube as the supply becomes exhausted.
The Moore lamps utilized nitrogen or carbon dioxide as the luminous gas, Moore’s innovation compensated for the gradual loss of gas in the lamp to the electrodes and the glass. Carbon dioxide gave a good quality white light. The first commercial installation was done in 1904 in a hardware store in Newark, New Jersey. The lamp yielded about 10 lumens per watt, which was about triple the output of incandescent lights based on carbon filaments.
Arthur Bright has written, Despite the fact that the tube was expensive to install, complicated, and required very high voltages, its operating advantages were great enough for it to find restricted use in stores, offices, and similar general lighting uses as well as in photography and some advertising and decorative applications.
The modest success of the Moore tubes was among the drivers for developing better filaments for standard incandescent light bulbs. Tungsten filament bulbs were a sufficient improvement over carbon filaments that the Moore tubes gradually disappeared from the market, leaving only short carbon-dioxide tubes in use for color matching, in which they excelled because of their daylight color. The General Electric Company absorbed the two Moore companies and Moore’s patents in 1912. Moore himself rejoined General Electric’s laboratory force.

John Logie Baird



Birth date : August 13rd, 1888
Birthplace : Helensburgh
Go back to death : June 14th, 1946
Place of death : Bexhill-one-sea
Profession : engineer
Diploma : electronic engineering
University : Technical school Glasgow, the university of Strathclyde
John Logie Baird is a Scottish engineer, handicapped by a very bad health, he gives up his trade of engineer in electrical energy in 1922 to devote himself to research on television. In 1924, it succeeds in reproducing simple geometrical forms and in 1925, a recognizable human face but the results is too poor to be taken into account. January 26th, 1926, of the members of Royal the Institution attend the first true meeting of television, the public demonstration taking place in 22 Frith Street, in the laboratory of the engineer. John Logie Baird becomes the first to produce a televised image of objects moving. In 1927, it transmits an image between London and Glasgow. In 1928, it creates a system of television color. It is charged by the German Post offices, in 1929, to develop a television channel. When the BBC launches its first chain in 1936, its system is in competition with that of Marconi Electric and Musical Industries. But the BBC chooses the system of Marconi in 1938.

Charles Francis Jenkins



Birth date : August 22nd, 1867
Birthplace : Dayton
Go back to death : June 5th, 1934
Place of death : Washington
Profession : shorthand writer, projectionist, inventor
University : Earlham college
Charles Francis Jenkins is an American inventor who was a pioneer in the fields of the cinema and television.
Biography
Jenkins became also business man at the end of his life, with its laboratories, Charles Jenkins Laboratories and his company of television founded in 1928, Jenkins Television Corporation. Although it was one of the most obscure inventors of television, its work had a determining importance and its life was marked by the deposit of more than 400 patents.
After having worked as shorthand writer in Washington, it began its experiments in the field of projection in 1891, which led it to leave its employment to be devoted fully to its research. He worked thus with the creation of his projector, Phantascope, which he presented to Atlanta and Philadelphia in 1895. With the assistance of the one of his comrades, Thomas Armat, it improved his projector, but following an argument and of a lost lawsuit, it had to give up its own invention, resold by Armat with Thomas Edison. Thereafter, Jenkins worked in the field of television, while concentrating on television without wire as from 1913. Its research succeeded only ten years later, and it had its results in public on June 13rd, 1925. It improves the neon light, known as lamp television, which placed behind the disc of Nipkow provides the light of image to the receiver. It obtained a patent on June 15th, 1925.

Ernst Alexanderson



Birth date : January 25th, 1878
Birthplace : Uppsala
Go back to death : May 14th, 1975
Place of death : Schenectady
Profession : engineer
University : Royal institute of technology
Diastinction : ANGER Medal off Honor, Edison Medal, National Inventors Hall off Famed
Ernst Alexanderson was an electric engineer suédo-American. It is one of the pioneers of the development of the radio and television.
Ernst Alexanderson was introduced with the National Inventors Hall off Famed in 1983, in Consuming it Electronics Hall off Famed in 2002. It received ANGER Medal off Honor in 1919 and Edison Medal in 1944.
The inventor of the high frequency alternator
Ernst Alexanderson is one of the great names of the history of electricity and broadcasting at the XXth century. It obtained 344 patents, of which the last in 1973, at the 95 years age.
It was born in Uppsala, in Sweden, on January 25th, 1878, but very early it settled in the United States to work with C.P. Steinmetz, the President of General Electric. It begins its career, at twenty-four years, in 1902, in the laboratories of General Electric with Schenectady, close to New York. Since 1904, General Electric lays down to him an objective, considered as unrealizable by a great number of experts of the time, to design a high frequency generator (100 Hz) for the pioneer of the T.S.F. Reginald A. Fessenden, with as requirement which the result was to be measured in kw. It succeeds in this operation, making it possible Fessenden to diffuse in Christmas 1906 the first radiophonic program containing of the songs and the music. Its system was based on a high frequency alternator allowing of the not weakened oscillations. It improved this system gradually, so much so that G. Marconi, which visited Schenectady in 1915, the superiority of the system of Alexanderson recognized on his clean. The famous speech on the fourteen points of President Woodrow Wilson was diffused at the end of the First World War by the Marconi station of New Brunswick using the alternator of Alexanderson.
The success of the alternator led to the creation of the Radio Corporation off America by General Electric in 1919.
A pioneer of mechanical television, being wary towards electronic television
The interest of Alexanderson for television dates from the middle of the Twenties, after the first demonstrations of Charles Francis Jenkins and by John Logie Baird, Alexanderson had assisted with the demonstrations of Jenkins, but had not found them convincing and wished not to depend on the patents of this one. January 17th, 1925, Alexanderson tested a using apparatus of the prisms of Benford, with the emission and the reception. In October 1925, General Electric had studied various possibilities of creating a system of television and had undertaken preliminary tests with a disc of sweeping and a controllable source of light conceived by Daniel McFarlan Moore, but also with a prism turning for the analysis and an oscillograph for the control of the light.
Various methods of analysis of the image tested (revolving prisms, wheel of mirrors as suggested since 1889 per Lazare Weiller, lenses revolving, oscillating mirrors and cathode-ray oscilloscope), it was concludes that the revolving prisms provided the most adequate method for the transmission of facsimile and television, while the technique of the oscillating mirrors was adapted for television amateur. In October 1925, Alexanderson considered that television was within reach, but that complementary elements such as the photocells, the control of the light and the methods of synchronization were to still be sophisticated. In October 1925, Alexanderson suggested the method of the multiple beams, which it described in detail in October 1926, in an article and its first patent application concerning television. The method was tested in September 1926. Without entering too many technical details here, one will summarize this system by saying that it required the reproduction, by projection on screen, of seven images containing 40000 units roughly each one and whose interlacing was to give an indication of quality of approximately 300000 units.

Elihu Thomson



Birth date : March 29th, 1853
Birthplace : Manchester
Date death : March 13rd, 1937
Place of death : Swampscott
diploma : engineer
Fields : engineer, inventor, president of MIT
Institution : institute of the electrical engineers of London, Thomson-Houston Electric Company
Biography
Elihu Thomson, its family emigrates towards Philadelphia in 1858. About 1880, it founds with Edwin J. Houston Thomson-Houston Electric Company, which amalgamates in 1892 with Edison General Electric Company to become General Electric Company. The name of Thomson remains attached to the British company British Thomson-Houston Company (BTH) and to the French company Thomson.
Thomson is at the origin of step less than 700 patents of which the wattmeter with induction. It was one of the first to denounce the dangers of x-rays.
He is president of MIT of 1920 to 1923.
Its last residence is declared National Historic Landmark in 1976.

William Duddell



Birth date : July 1st, 1972
Birthplace :
Go back to death : November 4th, 1917
Place of death :
Profession : electrical engineer, electrophysician
Institution : the Institute City and Guilds
Distinction : Fellow of Royal Society
William Duddell was a British electrophysician and electrical engineer. It continues its studies in private establishments, both in the United Kingdom and in France, and quickly obtains purses to attend the best schools. Among his inventions one can quote the mobile framework oscillograph, the thermal ammeter or the thermal galvanometer.
Before the invention of the incandescent lamp by Thomas Edison, in Europe the streets are lit by arc lamps which produce light thanks to an arc between two carbon electrodes. These lamps have a very bad output and produce a relatively weak lighting accompanied by a quite audible whirr. In 1899, Duddel was had a presentiment of to solve this problem. By showing that the whirr is produced by variations of electric current, its research leads it to invent the singing arc lamp which is able to produce notes of music using a keyboard. Thanks to this keyboard, it stops the oscillations of an electrical circuit and thus creates one of the first musical instruments electronics, and the very first instrument without amplifier nor loudspeakers.
During the presentation by Duddell of his arc lamp singing at the institute of the electrical engineers of London, one discovers that the lamps of other buildings, but connected on the same circuit, make hear the same notes of music as the system of Duddell during its demonstration. In spite of the enormous musical potential offered by the networks of public lighting, Duddell does not capitalize on its invention whose only interest will remain its innovation.
Duddell becomes member of the royal Company of London in 1907.

John Henry Poynting



Birth date : September 9th, 1852
Birthplace : Monton, close to Salford
Date death : March 30th, 1914
Place of death : Birmingham
Nationality : English
Fields : physics, electromagnetism
University : University of Birmingham, University of Cambridge
Re-elected : Vector of Poynting, Theorem of Poynting, Poynting-Robertson Effect
John Henry Poynting is an English physicist who worked, in others, on the electromagnetic waves. He was professor of physique in Mason Science College which became later the University of Birmingham of 1880 until its death.
Work
He defined what one calls the Vector of Poynting which represents the power per unit of area that transports an electromagnetic wave and the direction of this flow of energy. This vector is used in the theorem of Poynting, which establishes the conservation of energy of the electric fields and magnetic. It measured the gravitational constant of Newton by innovative techniques in 1893. In 1903 it was the first to realize that solar radiation could attract the small particles towards the Sun, effect recognized later under the name of Poynting-Robertson effect.
During the year 1884, it analyzed the prices of the produce exchanges, in particular those of corn, silk, and cotton, using statistical methods.
Craters over Mars and the Moon were named in its honor, just as the principal building of physics of the University of Birmingham and the association of the department of physics of this one, Poynting Physical Society.

John William McRae



Birth date: January 31st, 1848
Birthplace: Horton
Go back to death: November 29th, 1901
Place of death: Ottawa
University: Renfrew
John William McRae, business man and politician, wire of John McRae and Catharine McLeod, on December 18th, 1872, he married in Hull, Quebec, Catherine Wallace Bell, oldest daughter of Robert Bell and they had three wire and two girls.
John William McRae made his studies with Renfrew, in High-Canada and worked during a few years with his father, of Scottish origin, owner of a mill with Smiths Creek, then of another in Renfrew. Left for rather young Montreal, it is established later in the area of Ottawa, obviously about 1872, it was then representing of Ottawa and Rideau Forwarding Company of Montreal. It had its office in the Victoria island, with the Chaudière falls, but lived in the province of Quebec, seems he. About 1875, it settled with its family in the prestigious district of Coast-of-Sand, in Ottawa and founded a company of coal merchants and forwarding agents, the John William McRae and Company. It continued nevertheless to represent Ottawa and Rideau Forwarding Company during a few years. From 1877 to 1879, while he lived Coast-of-Sand, he was city council man district St George.
About 1880, John William McRae settled in the upper town, more close to his district of businesses and broke his bonds with the company montréalaise forwarding agents. Its association, from short duration, with Benjamin Ahern, in the sector of coal and that of the insurances, where they represented the Canadian Company of life insurance, known as of the Sun, from Montreal, was followed into 1881 of a longer association with a firm of forwarding agents, the Denis Murphy and Company. It continued to exploit the John William McRae and Company who, in 1883, added various products to his stock, of which pig iron and pipes of drainage. In the years 1890, McRae and Murphy had their name in the directories of the city as associated with Cassius C. Ray in the trade of coal and as owners of Ottawa Transportation Company Limited.
In the years 1880, John William McRae had become one of first associated with Warren Young Soper and of Thomas Ahearn in the setting-up of companies of electric trams and lighting in Ottawa, though its relations with them seem to have been ambiguous and broke before its death. The three men would have initially founded, in 1882, Ottawa Electric Light Company, in order to install electric lighting in the streets of the city. McRae, Ahearn and the liberal deputy of Ottawa to the legislative Parliament of Ontario, Erskine Henry Bronson, belonged to the new group of business men who, in 1894, constituted Ottawa Electric Company under the terms of a federal charter which, hoped, would withdraw them from the local by-laws and provincial, and would thus allow them to absorb all the rival companies, of which Ottawa Electric Light Company. McRae was vice-president in 1899. It also seems to have worked with Ahearn and Soper, of 1891 to 1894, to amalgamate their company, Ottawa Electric Street Railway Company, with Ottawa City Passenger Railway Company in order to prevail itself of the federal charter and the perpetual privilege of the latter. John William McRae was president of the company which resulted from it in 1898. These two fusions aimed at creating a monopoly in the sector of electricity and public transport in Ottawa, with the support of the liberal governments federal and provincial. It is however difficult to know which McRae influence had in these initiatives, it is probable that he was a figurehead.
In 1899, John William McRae became principal promoter and vice-president of Consumers' Electric Company, rival of Ottawa Electric Company. On the order of the municipality, it made include in its charter a clause antimonopole preventing that the company is repurchased. It is possible that, conservative of long time, it took part in the crusade of the party launched by the municipality against the monopolies, since 1894, the latter had succeeded in making cancel the charter and the perpetual privilege of Ottawa City Passenger Railway Company. According to the obituary which appeared in Ottawa Evening Journal with died of McRae in 1901, Consumers' Electric was then about to provide electric lighting to the city, one also reads there that McRae and the company had engaged quickly [on flies] of success, but under difficult conditions and in spite of an opposition that few men could have supported. Inter alia difficulties, there had been the fire of 1900, which had not only shaved the installations of the company, but also destroyed the companies of carbide and manufacture of paper founded by McRae the previous year.
In 1901, John William McRae had interests in several companies, particularly in Canadian Railway Accident Insurance Company, which it had founded with others in 1894 and of which he was president. He also had bonds with McRae Trading Company, Prescott Elevator Company, Ottawa Because Company, Electric Mining Company, North Star Mining Company and Ontario Graphite Company Limited. In its obituary, the Newspaper stressed that McRae, with the head of 18 companies, was perhaps most known of all the business men of Ottawa. The exhaustion of its fortune and the articles of newspapers on its financial problems however give to understand that its business was centered on the speculation. Member with life of the board of directors of Ottawa Protesting Home for the Aged, McRae formed also part of the committee of the secular businesses of the church presbytérienne St Andrew, which he attended, it was interested in hunting and the shooting and was promoter of the athletics.
John William McRae died suddenly in November 1901, killed by a ball which it itself had drawn, in a room of toilet of the offices of Canadian Railway Accident Insurance. With the investigation of the coroner, the jury, composed business men for the capital according to Ottawa Citizen, concludes that it had found death by making accidentally leave the gun that it cleaned. The municipal council convened a special meeting to lay down the methods of his representation at funerals and the stores of the street Wellington closed their doors when the funeral procession passed.

Phillip Hagar smith



Birth date : April 29th, 1905
Birthplace : Lexington
Go back to death : 29 aouts 1987
Place of death : Berkeley heights
University : Medford
Diploma : engineer
profession : Beautiful Laboratories Telephone, Radio operator electric Western
Phillip Hagar Smith is interested rather early in radioelectricity like with the emission of amateur, it transmits with the code 1ANB, it will obtain in 1928 its diploma for the occupation of engineer.
It then integrates famous the Beautiful Laboratories Telephone and work in the design and the installation of directing antennas for the stations AM of broadcasting. At that time heroic, the theoretical knowledge of the lines of transmission rested on work going back to 1911 of J.A. Fleming and measurements were carried out by moving an apparatus provided with six or eight thermocouples coupled with the line by the means of inductances, a microphone-voltmeter was used as indicator. This measurement made it possible to determine the relative amplitude and the position of the maximum and minimum of tension. It is thought that it is the heaviness of these operations to adapt the impedances which encouraged Phillip Smith to consider a more rational system aiming at modelling the line before passing to the practical experiments.
The abacus of Smith was not born in day, it is resulting from a long ripening of the reflection of its inventor. It took several forms and was stabilized about 1937 when Phillip Smith worked with B. Ferrell and J.W. McRae.

John Ambrose Fleming



Birth date : November 29th, 1849
Birthplace : Lancaster
Go back to death : April 18th, 1945
Place of death : Sidmouth
University : University of Cambridge, the University of Nottingham and University College of London, Victoria institute
Diploma : engineer
Profession : Radio electricity, physicist, electrical engineer
Re-elected : Famous for rule of the electron left hand tube, grid of Fleming
Distinction : Hughes medal, Faraday Medal of Chemical Society, ANGER Medal off Honor, Franklin Medal, Fellow of Royal Society
John Ambrose Fleming is an English physicist and electrical engineer. He passed to the posterity as an inventor of the kenotron, the first lamp for thermionic purpose or electron tube, which is the ancestor of the diodes with semiconductors. In Great Britain one allots the rule of the left hand to him.
Ambrose Fleming was the elder one of the seven children of Doctor James Fleming, Pasteur congregationalist, and was baptized on February 11th, 1850. He learned how to read with his mother. He started to attend the school towards the ten years age: it was a private school and it tasted the lessons of geometry particularly there.
Any young person still it aspired to becoming engineer. With the 11 years age it had a small workshop where it manufactured models of ship and engines. It manufactured even a camera, inaugurating by there its passion for photography. It continued its secondary studies of 1862 to 1866 in a college, University College School, in the London district of Hampstead but, the financial resources of its family being insufficient so that it can follow a training of engineer, it obtained this diploma via a course of education in alternation.
It was registered in license in sciences in University College of London, had as professors the mathematician Augustus de Morgan and the physicist Carey Foster and left graduate in 1870. He studied chemistry with the Royal College off Science of South Kensington in London. He was very pious and preached even a day with St Martin-in-tea-Fields in London, exposing the evidence of the possibility of resurrection. The chemical pile of Volta was the subject of its first scientific article, of which it gave reading in front of Physical Society of London. New money worries forced it to take again an activity paid during the summer 1874: it accepted a work of repeater of sciences in Cheltenham College, a Public school, it also taught in Rossall School.
It did not continue of them less its own research and it corresponded with James Clerk Maxwell to the University of Cambridge. It was allowed with St John' S College Cambridge in October 1877. The conferences of physics of Maxwell, said it, were difficult to follow: Maxwell spoke in an obscure way and expressed himself by allusions and paradoxes. Certain days, Fleming was only the student present. Fleming was laid off in arts in 1881, this time with First Class Honors in physics and chemistry.
It passed its thesis of doctorate to London and was used one year for the university of Cambridge as preparer of mechanics, before being appointed first professor de Physique and of mathematics of the University of Nottingham, it gave up however this station at the end of one year and became Fellow of St John in 1883. Thereafter he taught in various universities of which the University of Cambridge, the University of Nottingham and University College of London, where he was the first professor of electronic engineering.
With its departure of the University of Nottingham in 1882, Fleming became engineer consulting in electricity for Edison Electrical Light Company, the very recent co. Ferranti turned towards the applications of the alternative course, for the Co Marconi of wireless telegraphy, Swan Company, and later of Edison Electric Light Company.
In 1884 Fleming lives itself to offer the first pulpit of electronic engineering of England, created in University College of London. In spite of the horizons which this new station opened to him, it indicated in its autobiography that the only material placed at its disposal was a black board and a piece of chalk. June 11th, 1887 he married Clara Ripley 1856 ⁄ 7-1917, girl of a lawyer of Bath. In 1892, Fleming off published in the newspaper of the Institution Electrical Engineers of London an important article on the theory of the electric transformer. In 1897, the university opened a new laboratory in homage to the founder of Cable with Wireless, John Pender and Fleming was the first member elect of Pender Chair. In 1899, Fleming became scientific adviser of Marconi Company and soon started to work on a project of power station allowing the transatlantic TV-transmissions.
Painter and achieved photographer, Fleming practiced also the alpinism. November 16th, 1904, it patented the rectifying tube with two electrodes, which it called oscillating grid. One called indifferently this component lamp for thermionic purpose, diode with vacuum, kenotron, thermionic or rectifying tube of Fleming. This invention is generally regarded as the birth certificate of electronics, because it is about the first lamp rectifier. This precursor of the triode and the posterior rectifying circuits was also the first composing strictly speaking electronic. But in 1906, the American Lee De Forest associated with the rectifier a grid of control, creating the vacuum-tube, a radio operator tube detector. Fleming showed it plagiarism, but the Supreme court of the United States broke its patent due to insufficient precise details, adding that the technology of this apparatus was already known at the time of the deposit. De Forest improved soon its invention and with Edwin H. Armstrong developed the first electronic amplifier, the triode.
This invention played a crucial role in the creation of the telephone and the radio communications with long distance, the radar and the first electronic computer electronic computers. The legal battle around these patents lasted several years, the victories alternating for each camp Simultanément, Fleming contributed to photometry, electronics, the wireless telegraphy, and the electrical measurements. It launched the term of power-factor to describe the effective power of the alternative course.
In the years which followed, the technology of the lamps gradually relegated that of the diode to point with the row of old-fashioned thing, and with other components, it printed its first dash with the electronics industry. The diode of Fleming equipped the radio operator receivers and radar during decades until it is supplanted by the electronic technology of the solid more than 50 years later. The lamps were massively used until the invention of the transistor, and disappeared finally only with the beginning of the year 1970.
Fleming took its retirement of University College of London in 1927 to 77 years. Become widowed, he married on July 27th, 1928 in second weddings a high-speed motorboat of the song of then, Olive May Franks, of Bristol-board. He continued to have a public life, praising the merits of television and became even the first president of Society Television. He was anobli in 1929, and founded with Douglas Dewar and Bernard Acworth the Evolution Protest Movement in 1932. He accepted off ANGER Medal Honor in 1933 for the conspicuous share He played in introducing physical and engineering principles into the radio operator Article He died out in his house of Sidmouth in 1945. Died without children, Fleming bequeathed the essence of its goods at Christian charitable institutions. Its contributions to the electronic transmissions and the radar had been of vital importance for the Allies during the Second world war.

James M.Early



Birth date : July 25th, 1922
Birthplace : Syracuse
Go back to death : January 12th, 2004
Place of death : Palo Alto
Profession : engineer
University : New York College off Forestry, University of state of Ohio
Diploma : Baccalaureat in sciences of the pastes and papers, master in science
Jmaes M.early was an American electric engineer. It was known for its work in the field of development of semiconductors, in particular by the éponyme Early effect in the transistors.

Jonas Wenström



Birth date : august 4th 1855
Birth place : Hällefors
Go back to death : december 11th 1893
Place of dead : Västeras
University : Ecole Karolinska à Orebro
University : University of Uppsala, Oslo University
Fiels : engineer
Jonas Wenström to ASEA worked for the company, he developed the three-phase electrical system for which he obtained a patent in 1890 after a legal battle against Nikola Tesla. He also developed an electric direct current generator.

Ludwig Mond



Birth date : March 7th, 1839
Birthplace : Cassel
Go back to death : December 11th, 1909
Place of death : Regent' S Park
Nationality : German and British
Fields : industrial chemistry
University : Brunner Mond Company, Mond Company Nickel
University : University of Marburg, University of Heidelberg
Famous : Discovered commercial use of the Solvay process, of nickel carbonyl
Distinctions : Large cord about the Crown of Italy
Ludwig Mond is a chemist and an industrialist of German origin which took British nationality. It is one of the founders and owners of Brunner Mond, company for which it developed various industrial processes, of which that of the production of soda.
Biography
Ludwig Mond was born in an Jewish family in Cassel, Germany. his ⁄ her parents are Meyer Bär (Moritz) Mond and Henrietta Levinsohn. After having followed courses to the schools of its city, he studies chemistry at the University of Marburg under the supervision of Hermann Kolbe like at the University of Heidelberg under the supervision of Robert Bunsen, but forever received diploma. Then, he works in various factories in Germany and in the Netherlands before being established in England where he works on behalf of the John Hutchinson and Co with Widnes in 1862.
In october 1866, he marries his cousin Frida Löwenthal (1847-1923) in his birthplace of Cologne. They will have two children on the British ground: Robert and Alfred.
He also works in Utrecht on behalf of the P. Smits of Wolf of 1864 to 1867, then turns over to Widnes. He develops in collaboration with John Hutchinson a process to recover the sulfur of the rejections of the Leblanc process, used for the manufacture of soda.
In 1872, Mond meets the Belgian industrialist Ernest Solvay who developed a more effective chemical process for the manufacture of soda, the Solvay process. The year according to, it forms a partnership with the industrialist John Brunner with an aim of making the Solvay process commercially viable. It consitute then the company Brunner Mond Company, building a factory with Winnington in Northwich. Mond surmounts several obstacles which make the process difficult to industrialize. In 1880, it makes it commercially gravitational. In the 20 years space, Brunner Mond becomes the largest soda producer in the world.
In 1880, Mond takes British nationality. Whereas it assembles its company, its family lives in Winnington and, in 1884, it moves in London. To the beginning of the year 1890, it passes the majority of the winters to Rome. This house, the Zuccari palate, is rented initially, then bought in 1904 in the name of the friend of his wife, Henriette Hertz, who will make of it a center of study of the history of art: Bibliotheca Hertziana.
Mond sought new industrial chemical processes. He discovered nickel carbonyl, a new compound, which breaks up easily to form pure nickel starting from the ore thanks to the process Mond. He founded Mond Nickel Company to exploit this process. The nickel ores coming from the Canadian mines were nouveau riches before being dispatched with the factories of Mond Nickel Company in Clydach, Swansea, Wales where they were purified.
He dies in London in his house, The Poplars, Avenue Road, close to Regent' S Park. Even if it forever pratiqueé of ritual monks, it is buried according to the Jewish funerary rites with St Pancras and Islington Cemetery where its sons made set up a mausoleum. At the time of its death, its to have real at 1 million pounds sterling is estimated.

William Robert Grove


the father of the combustible batteries

Birth date: July 11th, 1811
Birthplace: Swansea
Date death: August 1st, 1896
Place of death: London
Profession: lawyer and chemist amateur
William Grove produced the first combustible battery in 1839. It based its experiment on the fact that to send an electric current through water water divides into these constitutive atoms: hydrogen and oxygen. Thus, Grove tried to reverse the reaction, to link hydrogen and oxygen to produce electricity and water. It is the base of the combustible battery. The combustible battery term was invented later, in 1889, by ludwig Mond and Charles Langer, which tried to build the first practical device using the air and of industrial gases. Combustible batteries are born when William Grove immersed two platinum bands, surrounded by tubes closed which contained hydrogen and oxygen, in an acid electrolyte. The original combustible battery of William Grove used of the diluted sulphuric acid because, by using an aqueous electrolyte, the reaction depends on the pH.
Structure of a pile with combustible
published by Grove in one of the first comptes
rendu on the exploitation of the combustible batteries.
This first combustible battery became the prototype of the pile with phosphoric acid (PAFC), which had a launching phase longer than those of other technologies of combustible battery. Unfortunately, it was obstructed by the inconsistency of the performances of the pile, but it included ⁄ understood already the importance of the contact of the three phases, gas, electrolyte and platinum for the generation of energy. It passed the majority of its time to seek an electrolyte which would produce a more constant current. It found several electrolytes being able to produce current, but it always fought for coherent results. It had also noted the commercial potential of this method of energy production if hydrogen could replace coal and wood like the means of energy.

John Alfred Valentine Butler



Birth date : February 14th, 1899
Birthplace : Winchombe, the United Kingdom
Go back to death : July 16th, 1977
Profession : electrochimist and physicochemist
University : University of Birmingham, University College of Swansea, University of Edinburgh
John Alfred Valentine Butler was a electrochimist and British physicochemist who contributed in a decisive way to formalization of the electrochemical kinetics. He obtained his thesis of the University of Birmingham in 1927. From 1922 to 1939, it continued an academic career in University College of Swansea then at the University of Edinburgh.
In the years 1920, it carried out initial work which led the German physco-chemist max Volmer (1885-1965) and his ⁄ her Hungarian collaborator Tibor Erdey-Grùz (1902-1976) to formalize the relation of Butler-Volmer in 1930.
At the end of his career, John Alfred Valentine Butler devoted himself to biochemistry at the Institute Courtauld de Biochimie and Chester Beatty Research Institute. He was the first studied, in 1941, the enzymatic kinetics of a purified enzyme: trypsin. It was also interested in the molecular mechanisms intervening in cancers.
Of a discrete naturalness, it was accustomed to being devoted to long solitary meditations, which was worth a reputation of original personality to him.

Max Volmer



Birth date : May 3rd, 1885
Birthplace : Hilden
Go back to death : June 3rd, 1965
Place of death : Postdam
Profession : physicochemist
University : university of Marbourg, university of Leipzig, Friedrich-Wilhelms university, technical university of Berlin Charlottenburg
Max Volmer with followed academic works to the university of Marbourg (1905-1908), at the university of Leipzig (1908-1910) or it obtained its thesis in 1910 thanks to a study on the vacuum photochemical reactions. It began its career as assistant at the university of Leipzig in 1912. It settled in Berlin in 1916 when it worked at the Institute of chemistry of the Friedrich-Wilhelms university on subjects concerned with the chemical weapon. From 1918 to 1920 he works within the Auergesellschaft private company. In 1920, it is named professor of electrochemistry and chemistry-physics at the university of Hamburg. In 1922 it is named full professor of the prestigious pulpit of chemistry-physics of the technical university of Berlin Charlottenburg which was held before him by Walther Hermann Nernst. It then devoted most of its work to the electrochemical kinetics with its Hungarian pupil Tibor Erdey-Grùz (1902-1976) of which it directed the thesis of 1928 to 1931.
In the years 1930, he proposed with the British physicochemist John Alfred Valentine Butler the relation of Butler-Volmer.
During the war, the technical university of Berlin formed a great number of technical experts and scientific of Third Reich. In 1945, during the invasion of Germany by the Red Army, it was taken along in Union of the Soviet socialist republics by Department 7 of the NKVD with many German scientists of foreground, like Gustav Ludwig Hertz and Peter Adolf Thiessen. Eager to keep possible reprisals of the Soviet authorities following their proximity with the National Sozialistische Deutsche Arbeiter Partei, they negotiated their reversal. Volmer worked in a research center in Union of the Soviet socialist republics on the Soviet atomic project. In parallel the USA carried out the Overcast operation which will allow recruitment by the Americans of 1600 German scientists, all fields included/understood. The French Army, as for it, put the hand on most of the engineers and persons in charge of the project of the BMW turbojets what allowed the design of turbojets SNECMA Atar. Max Volmer contributed to the development of the production processs plutonium and heavy water enriched for the Union by the Soviet socialist republics until 1955. It had then the authorization to turn over to East Germany and found its pulpit at the technical university of Berlin. In 1958 he became president of the Academy of Science of the German Democratic republic and took his scientific retirement.
After its death, the Institute of chemistry-physics of the technical university of Berlin was baptized Institut max Volmer. A street of Berlin-Adlershof is called max-Volmer-Strasse in the district of the Humboldt university of Berlin.

Rene Andre Audubert


Birth date : November 1st, 1892
Birthplace : The Pujols-on-Dordogne
Go back to death : 18 aouts 1957
Place of death : Paris
Profession : chemist and physicist
University : Faculty of Science, National School of Chemistry, University of Paris, Ecole Pratique des Hautes Etudes, National Conservatory of Arts and Crafts
Rene André Audubert is a French physicochemist. Wire of a doctor, Rene Audubert made of the scientific higher learning to the Faculty of Science of the university of Bordeaux and obtains the science degree there physics in 1913. Graduate of higher learning in 1914, it is then mobilized in the army for five years. Reached by gas, it is affected as radiologist in the center of physiotherapy of Troye. Demobilized in 1919, he then becomes preparer for the certificate of physics, chemistry and natural science with the Faculty of Science of the university of Paris and preparer of the course of physics applied to the national Academy of arts and trades. He then starts research tasks within the laboratory of chemistry-physics of Jean Perrin. In 1922 it obtains the science doctorate physics in front of the Faculty of Science of the university of Paris with a principal thesis entitled Actions of the light on the suspensions. Become assistant in 1928, it in charge of the direction of practical works and teaching with chemistry-physics at the institute of chemistry with faculty and obtains the direction of a new physical chemistry laboratory within the institute, financed by the 2nd section of the practical School of the high studies. Named chief of work to faculty on January 1st, 1937, it is in charge of a course of electrochemistry intended for the candidates with the certificate of general chemistry then to the certificate of thorough chemistry. It is also in parallel chief of work to the Academy. With Faculty, Rene Audubert is named on a new senior lectureship of electrochemistry on January 1st, 1946, and becomes at the same time part-time lecturer of electrochemistry to the Academy. In 1953, it is named full professor with personal capacity with faculty and becomes in 1956, one year before its death, holder of a new pulpit of electrochemistry to the Academy. Marguerite Quintin succeeded to him the senior lectureship of electrochemistry of faculty and the head of and the physical electrochemistry chemistry laboratory of the practical School of the high studies while Maurice Bonnemay succeeded to him the pulpit of the Academy.
Work
It contributed in a decisive way to the development of the electrochemical kinetics while being a precursor of the modern theory of the electrochemical overpressure in 1924, which led in 1930, max Volmer and Tibor Erdey-Grùz has to propose the formalism of the relation of Butler-Volmer.
Acts of resistance
During war 39-45, it took part in the resistance network of the Collège de France. It made kingpins in his laboratory of the institute of chemistry, and was photographed there by Robert Doisneau. It took part, on May 2nd, 1944, with the escape from the scientist Paul Langevin, who 72 years old was evacuated towards Switzerland whereas it was assigned with residence with Troyes. Rene Audubert and his assistant, Marguerite Quintin, contributed to the exfiltration of Paul Langevin towards Switzerland by hiding it in the Parisian residence of Audubert until May 4th. It also hid Jewish scientists there, like the biophysicist Rene Wurmser.

Oliver Heaviside



Birth date : May 18th, 1850
Birthplace : Camden
Go back to death : February 3rd, 1925
Place of death : Torquay
Profession : Physicist and mathematician
Distinction : medal of Faraday
Study : autodidact
Oliver Heaviside is a self-educated British physicist. He formulated again and simplified the Maxwell's equations under their current form used in vector calculus.
Although it had school good performances, it left the school at the sixteen years age and became operator of telegraph. However it continued to study and, in 1872, whereas it worked as operator chief in the Newcastle-upon-Tyne, it started to publish its results of a search in electricity.
Between 1880 and 1887, it developed operational calculus, a method to solve differential equations by transforming them into ordinary equations algebraic what was worth to him many criticisms when it introduced it for the first time, because of a lack of rigor in the use of derivation.
In 1887, it suggested that induction coils should be added to the cable of the transatlantic telephone in order to correct the distortion from which it suffered. For political reasons, that was not done.
In 1902, he predicts the existence of conducting layers for the radio waves which enable them to follow the curve of the ground, these layers, located in the ionosphere, are called layers of Kennelly-Heaviside, the name of Arthur Kennelly, American physicist who had the same intuition as him. They were finally detected in 1925 by Edward Appleton.
It also developed the function of Heaviside, used commonly in the study of systems automatically and it studied the propagation of the electric currents in the drivers.

Hermann von Helmholtz



Birth date : August 31st, 1821
Birthplace : Potsdam, Prussia
Go back to death : September 8th, 1894
Place of death : Charlottenburg
Nationality : German
Fields of studies : Physics, psychology
University : University of Königsberg
University : University of Heidelberg
University : University of Berlin
University : University of Bonn
Diploma : Friedrich-Wilhelm institute
Re-elected : Free energy
Distinctions : Medal Copley, Faraday Lectureship
Hermann Ludwig Ferdinand von Helmholtz is a scientist physiologist and physicist, It in particular made important contributions to the study of the perception of the sounds and colors like with thermodynamics.
Biography
After its studies at the Friedrich-Wilhelm-Institute, it started its career as army medical officer and became then professor of anatomy and physiology, then professor of physics in Berlin in 1871. Its teaching qualities were however hardly reluisantes, at least according to one of its pupils, the future physicist max Planck who said, in his autobiography, which its teaching annoyed it as much as us. This last became however his ⁄ her colleague, by taking possession of the pulpit of theoretical physics in Berlin, primarily appreciating the man and the scientist.
Helmholtz lived at one favourable time to develop the experimentation thanks to an arsenal of increasingly powerful instruments, which prolong, gears down, amplifies, accelerates the glance of the scientists on nature of the phenomena (and in this precise case, of the sound phenomena) to highlight the explanations of certain observations: the technique made it possible to transcribe in an objective form of the unexplainable phenomena and acoustics, and the psychophysical one, carried out a considerable jump.
Helmholtz was prize winner of the Copley medal in 1873 and Faraday Lectureship of Royal Society off Chemistry in 1881.
The institution of German research, Helmholtz-Gemeinschaft is named in its honor.
Work
Its principal work sound
Electrophysiology, nerve impulse
Work on the vision, presented in its handbook of physiological optics in three volumes, recognized like a work pioneer on the matter. He is the author of a physiological theory of the music, which will refer during all first half of the XX ecentury. Its writings revolutionized acoustics, and mainly the musical acoustics.
Physiological optics : The assumption of Thomas Young, according to which the perception of the color is due to the presence on the retina of three types of receivers which react respectively to the red, the green and blue, will be developed by Hermann von Helmholtz and will be checked in experiments in 1959 Young-Helmholtz theory.
Physics : definition of the potential energy, formulation of the principle of conservation of energy, laws on the swirls, work on the importance of the sound harmonics, decomposition in Fourier series, laws of geometrical optics in the concept of stamp
Chemistry : Theorem of Gibbs-Helmholtz (thermochemistry)
Theory of perception
Helmholtz develops a semiotic theory according to which our feelings are signs of the external objects which are the cause. This approach takes as a starting point the theories empirists in particular developed by John Locke, but especially by the theory of specific nervous energies of Johannes Muller: qualities of the external things are only powers able to produce in us certain impressions without it being possible for us to determine if these effects are or not resembling what causes them.
We call feelings, the impressions produced on our directions, as them seem to us only particular states of our body, especially of our nervous apparatuses, we give them on the contrary the name of perceptions, when they are used to us to be formed representations of the external objects
Physiological theory of the music
Music and consonance
Unfortunately, starting from this new scientific method, he extrapolates deductions on the perception of the consonance and the dissonance. Its research of the physical bases of perception led it to express the physiological character of the feeling of dissonance which would be due to a flow of beats between harmonics: the seventh, for example, would be dissonant in his report/ratio of second with harmonic 1.
But extension of this theory of the resonators to analogies between 24000 fibers of the membrane basilaire and the 20000Hz of the auditive surface leave perplexed. It would point by point suppose an adequacy between the selective action by resonance of the bodies of perception, and the model of the resonators developed by Helmholtz. However such an extension fishes by its too great simplicity. The fibers which compose the membrane basilaire are neither rather flexible nor enough free to be able to dissociate and form, each one separately, a resonator. Moreover the smoothness of our hearing (Weaver will admit the possibility of distinguishing up to 64 heights different in a semitone in the neighborhoods from 1000Hz) multiplies in an inconceivable way the number of the resonators necessary and thwarts a “specific” location theory the perceived heights. More recent music research will thus get busy to measure these differential quanta of our perception.
Its theory also supposes that the ciliées cells of the internal ear are only of simple operators. The membrane basilaire would only be implied. This assumption was dismantled in 1948 by the theory of Gold.
One must in Georg von Békésy have shown that Helmholtz had been misled by considering that the membrane basilaire, presents in the cochlea, operated according to a mode of resonators. Békésy, chooses a model to him where portions of the membrane determine the perception heights of a sound.

Robert Williams Wood



Birth date : May 2nd, 1868
Birthplace : Concord
Go back to death : August 11th, 1955
Place of death : Amityville
Profession : physicist
Distinction : prize winner of the medal of Rumford
Biography
Robert Williams Wood, it is especially known to have invented a filter screen letting pass mainly the ultraviolet rays (wavelengths higher than 366 nanometers) commonly called black light or black light, its invention is marketed today in the shape of tube neon using a principle of phosphorescence, or cold light.
He discovered in 1905 optical resonance and worked on the spectroscopy, photography color, the emission of light using metal vapors, fluorescence in x-rays and the biological effect of radiations.
He put at the day the erroneous character rays NR of professor Blondlot in Nancy.
He showed in 1909 the erroneous character of the explanation of the greenhouse effect by the infra-red trapping of the rays by glass, simply by replacing ordinary glass by halite transparency with these rays.
He was prize winner of the Rumford medal in 1938.
He is also the author, with Arthur Train, of two science-fiction novels, The Man Who Rocked the Earth (1915) and The Moon Maker (1916), the first fiction where appears the topic become traditional of the modification of the trajectory of a dangerous asteroid for the Earth.
He also composed a book for children illustrated by his care, Flornithology, or How to distinguish the flowers from the birds (How to Such the Birds from the Flowers).
Since 1975, Optical Society off America decrees a price in the honor of Robert Wood rewarding for discovered or the inventions in the field of optics.

Alfred Perot



Birth date : November 3rd, 1863
Birthplace : Metz
Go back to death : November 28th, 1925
Place of death : Paris
Nationality : Frenchwoman
Profession : Physics
University : National laboratory of metrology and tests
Diploma : Polytechnic school
Famous : Interferometer of Fabry-Perot
Distinctions : Rumford medal
Biography
Jean Baptiste Gaspard Gustave Alfred Perot is born in Metz on November 3rd, 1863. He is the son of Gaspard Perot, polytechnician, officer of the genious, then general intendant. His ⁄ her mother, Laure Dufour, were the grand-daughter of the baron Dufour, director as a chief of the imperial Guard (First Empire), mayor of Metz, par of France (1769-1842) and the back grand-daughter of the baron Pougeard of Limbert, deputy of the seneschalsy of Angouleme to the General states of 1789, member of Old, prefect of High-Vienna, member of Tribunat, prefect Allier, appointed of Charente under the Restoration and the monarchy of July, chair general advice of Charente (1753-1837).
Left the Polytechnic school in 1884, it returns to Nancy to carry out its thesis in the laboratory of Rene Blondlot where it already implements clever and direct methods. In 1888, it supports its thesis of science doctor in front of the Faculty of Science of Paris with its work on the precise determination of constant thermodynamic for the calculation of the mechanical equivalent of heat.
In 1888, Perot is named university lecturer with the Faculty of Science of Marseilles. Young student, Charles Fabry still re-examines Perot at the beginning of his scientific career, with his tireless activity, his open mind, his exceptional skill of worker manual, building his hands the apparatuses necessary to his research, communicating his fire crowned with those which surrounded it.
Together they invent the interferometer with multiple waves, semi-silvered blades, officially called interferometer of Perot-Fabry, but more frequently named interferometer of Fabry-Perot today. Fabry had dealt with in an academic way the problem of the interference rings in its thesis, but Perot imagined an original experiment then, an electrometer whose two mobile terminals were the two metallized blades of the interferometer. The invention of this interferometer will start many work - measurement small thicknesses, determination wavelengths, spectroscopy, width of the spectral lines and kinetic theory of gases, experimental checking of the Doppler effect and Michelson effect. In approximately 250 publications will rise including 23 in Astrophysical Journal and much of honors and price, abroad as in France. In 1918, it is, with Charles Fabry, prize winner of the Rumford Medal of Royal Society for its work in the field of optics. In 1894, it is named professor of industrial electricity to the same faculty of Marseilles.
In 1902, it is named director of the National laboratory of tests (today National laboratory of metrology and tests) of the national Academy of arts and trades. It is there that the value in wavelength of the standard meter with the red line of Cadmium will be given.
In 1908, it succeeds Henri Becquerel with the Pulpit of physics of the polytechnic school. The same year it is named responsible for the solar spectroscopy at the observatory of Meudon. During the war it takes over temporarily the duties of Deslandres the head of this observatory and, under the orders of the future Ferrié general, it develops the lamp with three electrodes, the wireless telephony and the radiogoniometers. In same time it voluntarily ensures a service of radiography in hospital which could have deteriorated its health. With Bernard Lyot, one of his pupils, Perot invents devices for the automatic landing of the planes and the remote piloting of the boats in squadron.
After the war Alfred Perot takes again his activities of solar spectroscopist and brings the first experimental proof of the spectral shift of the solar lines envisaged by the general theory of relativity, it has its results, at the time of the famous conferences of Albert Einstein. The experimentation impassions it until the end of its life. He dies in 1925 in his Parisian residence, 16 avenue Bugeaud (the summer he lived his property of the Houssaye-in-Brie).

Rene Blondlot



Birth date : July 3rd, 1849
Birthplace : Nancy
Go back to death : November 24th, 1930
Place of death : Nancy
Profession : physicist
Place of Profession : university of Nancy
Biography
Prosper-Rene Blondlot is a French experimental physicist, he acquired a great reputation in the years 1890 to 1900 thanks to his experiments which in particular made it possible to confirm the results of Hertz in 1893 on the polarization of the magnetic fields.
He is especially known to have made one of greatest errors of the XX ecentury in experimental physics, by announcing, in 1903, his discovery of the rays NR. This hypothetical radiation, thus named in the honor of the University of Nancy where he professed, was supposed being able to increase the luminosity of a light of low intensity. In 1904 the physicist Robert William Wood revealed, in the Nature scientific magazine, that the phenomenon was purely subjective and no physical origin had : the phenomenon “had been observed” whereas it had however withdrawn some, clandestinely, the device release.
A park, which it bequeathed to the town of Nancy, bears its name.

Henri Becquerel



Birth date : December 15th, 1852
Birthplace : Paris
Go back to death : August 25th, 1908
Place of death : Croisic
Nationality : Frenchwoman
Profession : Physics
University : Polytechnic school
Diploma : Louis-the-Large college
Re-elected : Discovered spontaneous radioactivity
Distinctions : Nobel Prize of physics
Biography
Antoine Henri Becquerel. He is prize winner of half of the Nobel Prize of physics of 1903 (divided with Marie Curie and its husband Pierre Curie)
his ⁄ her father, Alexandre Edmond Becquerel, and his ⁄ her grandfather, Antoine Becquerel, were physicists, professors with the national Natural history museum of natural history of Paris. It is born even in these buildings. his ⁄ her father before him had also been born there.
He carries out his studies with the Louis-the-Large College. In 1872, it enters to the Polytechnic school, then in 1874 obtains the school of application of the Bridges and Chaussées.
In 1874, it Marie with Lucie Jamin, girl of Jules Jamin, one of his professors of physics at the Polytechnic school, with which he has a son, Jean (1878-1953). In 1890, he marries in second weddings Louise Lorieux, girl of Edmond Lorieux, general inspector of the Mines, and niece of the vice-president of the General advice of the Highways Departments.
He obtains his diploma for the occupation of engineer in 1877, and directs himself towards research. Its first work relates to optics, then it is directed again from 1875 towards polarization. In 1883, he studies the infra-red spectrum of the metal vapors, before devoting himself in 1886, with the absorption of the light by the crystals. He ends up supporting his thesis of doctorate in 1888.
The following year, he is elected with the Academy of Science, like his father and his ⁄ her grandfather had been it before him. After the death of his father in 1892, it continues its work and ends up entering as professor to the Polytechnic school in 1895, where it succeeds Alfred Potier.
In 1896, Becquerel discovered the radioactivity by accident, whereas it made research on the fluorescence of uranium salts. On a suggestion of Henri Poincaré, he sought to determine if this phenomenon were of comparable nature that x-rays. It is by observing a photographic plate put in contact with material that he realizes that it is impressed even when the material was not subjected in the light of the sun : the material emits its own radiation without requiring an excitation by light. This radiation was baptized hyperphosphorescence. He announces his results on March 2nd, 1896, with a few days in advance on work of Sylvanus Thompson which worked in parallel on the same subject in London. This discovery is worth the Rumford Medal to him in 1900.
In 1903, after the discovery of polonium and radium by Marie and Pierre Curie, Becquerel receives half of the Nobel Prize of physics (other half is given to the Curie husbands) in recognition of the extraordinary services which it rendered while discovering the spontaneous radioactivity. In 1908, he becomes foreign member of Royal Society. He dies some time later, with the manor of PEN Manor house, property that its in-laws, Lorieux, had in Croisic.
In addition, the physical unit of the radioactivity, Becquerel (Bq) was named according to him.


Michael Graetzel



Birth date : 11 May 1944
Birthplace : Bern
Nationality : Switzerland
Profession : cmimy, photochemistry
University : Polytechnic school of Lausanne, technical university of Berlin
Famous : Cell of gratzel
Reward : Millenium European innovation Prize (2000)
Reward : Faraday Medal of Royal Society (2001)
Reward : Dutch Havinga Award (2001)
Reward : Italgas Prize (2004)
Reward : McKinsey Venture Awards (1998 and 2002)
Reward : Gerischer Prize (2005)
Reward : Price Balzan (2009)
Reward : Millennium Technology Prize (2010)
Michael Grätzel is a Swiss chemist of German origin. In 2010, he is chemistry teacher at the federal Polytechnic school of Lausanne and person in charge of the laboratory the photonic ones and interfaces, belonging to the institute of chemical sciences and engineering.
He is, with his team, the inventor of the promising cells graetzel in the field of the conversion of solar energy into electrical energy. The developed materials could also allow a new form of optical storage of data the level nanoscopic. The cells graetzel have an output as important as the standard photovoltaic cells.
Since the years 2000, several other laboratories in the world study this type of cells. Their fast ageing still poses problem even if solutions exist.
It uses, inter alia, the natural dye of the plants to just like convert solar energy into electricity would do it the plants during photosynthesis.

Brian David Josephson



Birth date : 4 January 1940
Birthplace : Cardiff
Study : university of Illinois, Cambridge university
Profession : physicist
Reward : Holweck price, Nobel Prize divided with Ivar Giaever and Leo Esaki, Guthrie (Institute of Physics), Van DER pol., Elliot CRESSON (Franklin Institute), Hughes (Royal Company), Holweck (Institute of Physics and French Institute of Physics), Faraday (Institution of Electrical engineers), Mr George Thomson (Institute of Measurement and Control)
Brian David Josephson is a British physicist. Its work deeply transformed electric metrology. He is prize winner of half of the Nobel Prize of physics of 1973, other half was given to Ivar Giaever and Leo Esaki, for his theoretical prediction of the properties of the supercourants through a barrier tunnel, in particular these usually known phenomena under the name of Josephson effects. He also determined the constant of Josephson. He is prize winner of the Holweck price in 1973.
In 2011, Brian Josephson is director of the Project of unification of the matter and the spirit of the Group of theory of the matter condensed at the Cavendish laboratory of the University of Cambridge.
The objective of the project is mainly to include/understand, from the point of view of the theoretical physics, which can be characterised, for lack of better terms, like intelligent processes in nature, in bond with the cerebral function or other processes of nature. Josephson explains why the theoretical physics can help has to reorganise the prospects on these problems.
Brian Josephson present of the scientific ideas which were denounced by the whole of the scientists and invites to carry an attentive glance on these denunciations to subject them to the analysis.
Brian Josephson decided in favour of Rusi Taleyarkan and against the reports published about it by the Nature newspaper. He showed the CSICOP to use the media at ends of anti-paranormale propaganda. He supported, like later the prize winner of the Nobel Prize Luc Montagnier, work of Jacques Benveniste on the memory of water. He took the defence of the British stations, which had emitted an evoking stamp, in a commemorative series on the Nobel Prize, the possibility of an explanation of telepathy by means of the quantum theory. Brian Josephson also supports Rupert Sheldrake, the biologist who made say to the editor association of the nature magazine, John Maddox, who his book was to be flaring.
Whereas it is still student, Brian Josephson achieves in 1962 the feat of ingenuity theoretically to clarify the behaviour of the electrons which group in pairs of Cooper at the time of their passage under the barrier of potential between the two superconductors. It from of deduced two remarkable effects : on the one hand, that one supercourant should appear even in the absence of electric tension; in addition, that a high frequency AC current would cross the barrier subjected to a constant tension.

Leo Esaki



Birth date : 12 March 1925
Birthplace : Osaka
Study : the university of Tokyo, laboratories industrial, Engineer at Sony
Profession : physicist, engineer
Reward : Nobel Prize of physique 1973 shared with Ivar Giaever and Brian David Josephson
It develops the first quantum electronic system to with it : in 1958, it observes, in junctions p-n of very doped germanium, the penetration of an electron in a closed area of the solid, protected area by a classically insurmountable barrier of potential.
This tunnel effect is of nature purely quantum. In 1960, Esaki builds a diode, the diode with tunnel effect which bears its name, whose operation is founded on this effect. Short-circuit for a current being propagated in a direction, this component has a negative effective resistance.

Ivar Giaever



Birth date : 5 April 1929
Birthplace : Bergen
Profession : the polytechnic institute Rensselaer de Troy
Reward : Nobel Prize of physique 1973 shared with Brian David Josephson and Leo esaki
Born on 5 April 1929 in Bergen (Norway), Ivar Giaever is the son of a pharmacist. Its course is original : after its secondary studies, he works one year in a factory of ammunition, then follows the courses of the Norwegian Institute of technology of 1948 to 1952. After its military service, he works one year at the patent-office of the Norwegian government. In 1954, he emigrates in Canada, where he passes from a cabinet of architect to the research department of the Canadian subsidiary company of General Electric. He goes to 1956 to the United States, and he follows there the courses of electrical engineer of the General Electric company, which then engages it in its research centre at the same time as he studies physics at the polytechnic institute Rensselaer de Troy, in the State of New York.
From 1958 to 1969, Giaever makes contributions noticed to the physics of thin films, of supraconductivity and the comprehension of the quantum effects in the solids.
2 May 1960, it succeeds in measuring the forbidden band (the gap) of a sample aluminium-oxide of aluminium-lead brought up to a temperature of some Kelvins and its variation when lead becomes superconductive.
From 1970, Giaever studies many problems of biophysics, like the behaviour of the protein molecules on the surface of the solids or the movement of the normal or cancerous cells cultivated on electrodes. It leaves General Electric in 1988 to become professor at the polytechnic institute Rensselaer and the university of Oslo, where it took his retirement in 1994

Heike Kamerlingh Onnes


Birth date : 21 September 1853
Birthplace : Groningue, Netherlands
Go back to death : 21 February 1926
Place of death : Leyde, Netherlands
Nationality : Netherlander
Profession : physicist
Study : University of Leyde, University of technology of Delft, University of Heidelberg, University of Groningue
Reward : Nobel Prize of physics (1913)
Heike Kamerlingh Onnes was a Dutch physicist. He is prize winner of the Nobel Prize of physics of 1913 for his studies of the properties of the matter at low temperature, which carried out, inter alia, with the production of liquid helium. He also took part in discovered supraconductivity.
Onnes begins its academic works with Groningue. He studies then at the University of Heidelberg of 1871 to 1873 in particular under the direction of Robert Wilhelm Bunsen and Gustav Kirchhoff. He turns over then to Groningue where he obtains his master in 1878 and its doctorate in 1879 with a thesis entitled new evidence of the rotation of the ground. From 1878 to 1882, he is assistant of Johannes Bosscha, then directing of the polytechnic school of Delft, which he replaces as a reader of 1881 to 1882.
From 1882 to 1923, Onnes is professor of experimental physics at the University of Leyde. In 1904, it founds a large laboratory of cryogenics and attracts other researchers there, which contributes to its recognition by the scientific community. It is the first to succeed in liquifying helium on 10 July 1908 using cryostats, which is worth the Franklin Medal in 1915 to him. While using the Joule-Thomson effect, he manages to make decrease the temperature until less than 1 degree above the absolute zero and reached 0,9K. It is the coldest temperature ever reached at that time. The equipment which allowed him this realisation is today visible with the Museum Boerhaave de Leyde. He studies then the effects of the freezing cold on a certain number of gases and metals, which is worth the Rumford Medal to him in 1912.
From 1911, Onnes and its team made up of Gilles Holst, Cornelis Dorsman, and Gerit Flim study the electric monoatomic metal properties at very low temperature (mercury, tin, lead). At that time, certain scientists, whose William Thomson (Lord Kelvin), think that within a driver the electrons should be with the complete stop with the absolute zero, which should then lead to an infinite electrical resistance. Others, whose Onnes, think that this resistivity must decrease gradually up to zero. Indeed, Augustus Matthiessen had shown in years 1860 that the resistivity generally increases with the temperature in metals.
8 April 1911, the team of Onnes measures that the electrical resistance of mercury (because it is in particular very pure) becomes null in lower part of a certain temperature called temperature criticises Tc, about 4,2K for mercury. It is the first observation of a superconductive state : Onnes writes whereas mercury passed in a new state, which because of its extraordinary electric properties could be called superconductive state. Legends allotted the merit of discovered only to the student of K. Onnes, Gilles Holst, but the book of experiment discovered recently written hand even of Kamerlingh Onnes shows that this last was well with the orders of the experiment this day there, Gilles Holst measuring electrical resistance with a Wheatstone bridge with 30m of distance, the part where was cooled mercury undergoing too many vibrations because of the pumps, Cornelis Dorsman, and Gerit Flim dealing with the aspects of cryogenics.
After its death, work on cryogenics continues within its laboratory, to which its name in its honour is given. One of its students, and its successor as director of the laboratory, Willem Hendrik Keesom is the first to obtain solid helium.
Onnes gave its name to the Onnes effect observed in superfluid helium, like with the lunar crater Kamerlingh Onnes.

John Bardeen



Birth date : 23 May 1908
Birthplace : Madison, Wisconsin
Profession : physicist, geophysicist, professor
Reward : Nobel Prize of physics of 1972 on work on supraconductivity with Robert Schrieffer and Leon Neil Cooper, Price Oliver E. Buckley
Reward : It is co-winner with William Shockley and Walter Houser Brattain of the Nobel Prize of physics of 1956 for their work on the semiconductors
Reward : He was also prize winner of the Franklin Medal in 1975 for his work on supraconductivity and the semiconductors
Study : University of Wisconsin-Madison, University of Princeton, University of Illinois
John Bardeen is the second wire of an family of five children, he attends the schools of his birthplace and finishes the college at the 15 years age. He studies electrical engineering then, disciplines that he chooses for his practical and mathematical aspect, at the University of Wisconsin-Madison, where he obtains a control in sciences in 1929.
He enters the life professional then while working as a geophysicist in the department of research of the GULF Oil Company in Pittsburgh. He wearies himself some after three years, and resumes studies of mathematical physics at the University of Princeton, which delivers its doctorate in 1936 to him after a thesis on the solid state physics. During the writing of this one, it is proposed to him to join Harvard, which it accepts to work in particular on problems of conduction in metals with John Hasbrouck Van Vleck and Percy Williams Bridgman.
He begins his academic career in 1938 as a professor attending the University of Minnesota, year when he meets his future wife. He leaves his station in 1941, whereas the Second world war makes rage, to work in Naval Ordnance Laboratory, a research laboratory on the armament of the American army located at White Oak in Maryland. He refuses to join the Manhattan project in 1943 by calling upon family reasons.
At the end of the Second world war, it realises that the University of Minnesota offers only few futurologies for its research and prefers to join the Laboratories Beautiful. The group of physics solid state is directed by William Shockley and Walter Houser Brattain is one of the members. He will remain there until 1951, working in particular on alternatives to the electron tube what led it to develop the transistor, component of all the modern electronic devices, with his colleagues.
Bardeen turns then to academic research to the University of Illinois, where he is also professor of electrical engineering. Simultaneously with its activities of professorship, where it had as student of thesis the inventor of the electroluminescent diode Nick Holonyak Jr., it directs its research towards the comprehension of the mechanisms of supraconductivity. The formulation of a model of coupling of electrons and their interactions with the vibrations of the crystal lattice of the solids under the name of theory BCS, of initial of Bardeen and its colleagues Leon Neil Cooper and John Robert Schrieffer, makes it possible to explain the phenomena of null electrical resistance observed in the superconductors.
He is Co-prize winner with William Shockley and Walter Houser Brattain of the Nobel Prize of physics of 1956 for his research on the semiconductors and their discovery of the transistor effect.
He is also Co-prize winner with Leon Neil Cooper and John Robert Schrieffer of the Nobel Prize of physics of 1972 for their common theory of supraconductivity, usually called theory BCS. He is named professor emeritus in 1975. He dies of cardiac disorders on 30 January 1991 in Boston.

John Robert Schrieffer



Birth date : 31 May 1931
Birthplace : Oak Park in Illinois
Profession : physisician
Reward : Nobel Prize of physics of 1972 on work on supraconductivity with John Bardeen and Leon Neil Cooper, Price Oliver E. Buckley
Study : secondary study with Eustis and newyork, university MIT, university of Illinois
Schrieffer is born in Oak Park in Illinois. Its family moves in New York then with Eustis in Florida where it makes its secondary studies. It is then allowed in Massachusetts Institute off Technology where it studies initially electric engineering then turns to physics. It joined the university of Illinois with Urbana-Champaign, it becomes the assistant of John Bardeen there.
From its third year with Urbana-Champaign, Schrieffer works with Bardeen and Leon Neil Cooper, together they develop the theory which bears their names, theory BCS, the first complete microscopic theory of supraconductivity. This work is rewarded by the Nobel Prize for physics for 1972 for their common theory for supraconductivity, usually called theory BCS.
It receives in 1968 the Price Oliver E. Buckley decreed by American Physical Society.
Schrieffer was condemned to two years of prison in November 2005 to have caused an car accident killing a person whereas it was under the blow of a suspension of licence.

Leon Neil Cooper


Birth date : 28 February 1930
Birthplace : New York
Study : university of Columbia
Traverses : Princeton, the university of Illinois and with that of Ohio, he becomes professor at the Brown university in Providence in 1958
Professions : physicist
Reward : Nobel Prize of physics of 1972 on work on supraconductivity with John Bardeen and John Robert Schrieffer
Cooper made its studies in New York where it was born, first of all in Bronx High School off Science then at the Columbia university, where it obtained its master' S dismantles, then its doctorate. He teaches then in Institute for Advanced Study, at the university of Illinois, then at the university of Ohio. He joined, in 1958, the Brown university, where he still teaches in 2010.
Its educational course in the town of New York east close to that of its compatriot Melvin Schwartz, prize winner of the Nobel Prize of physics of 1988.
Its name was also used as inspiration to the character of Sheldon Cooper of the series The Big Bang Theory.

Vitaly Lazarevitch Ginzburg



Profession : physicist
Birth date : 4 October 1976
Birthplace : Moscow
Go back to death : 8 November 2009
Place of death : Moscow
Study : university of Moscow, Soviet Academy of sciences, the Lebedev institute, university of Gorki
Work : transitions from phase, supraconductivity
After theoretical research on the representations of particles of raised spin, it tries as of 1943 to adapt to supraconductivity the theory that Lev Landau had proposed two years earlier to describe the phenomenon of superfluidity. After years of effort, it publishes in 1950 with Landau a radically new theoretical analysis in which a complex function plays the part of parameter of order whose variations describe the passage of a solid of its normal state in a superconductive state. Seven years later, the theory of the pairing of the electrons at low temperature will allow John Bardeen, Leon Cooper and John Schrieffer to give a more fundamental explanation of the physical effect, which does not contradict of anything the more phenomenologic theory Ginzburg-Pram.
In addition to its most famous result which will be worth to him to divide the Nobel Prize of physics in 2003 with Alexei Abrikosov and John Leggett, Ginzburg also contributed in an important way to the development of radioastronomy, by studying in particular the wave propagation in the solar plasmas and radiations.
Denounced like cosmopolitan for the Stalinist period, Ginzburg escapes from little from vagueness from arrests of 1947. Extremely active against the anti-semitism after the fall of Communism, it takes part in 1996 in the foundation of the Russian Jewish Congress, organisation which militates in favour of the State of Israel. Convinced atheist and militant, it expresses his faith in only science but supports the assertion of a laic Jewish identity.

Lev Davidovitch Landau



Profession : physicist theorist
Birth date : 22 January 1908
Birthplace : Bakou
Go back to death : 1 April 1968
Place of death : Moscow
Residence : Moscow
Nationality : Soviet
Travux : Physics of the condensed matter
University : university of Kharkov, Lomonossov Institute
Graduate : University of State de Saint-Pétersbourg
Re-elected : quantum theory of the behaviour of helium
Distinctions : Nobel Prize of physics in 1962
Burial : cemetery of Novodiévitchi
Lev Davidovitch Landau was a Russian physicist theorist. He is prize winner of the Nobel Prize of physics of 1962 for his theories pionnières in connexion with the condensed state of the matter, particularly liquid helium.
Biography
Born in Bakou from a father, David, engineer in the oil, which was also administrator of the oil company of Alphonse de Rothschild, called BNITO until its sale in 1911, and of a mother doctor. Lev can read as of the four years age and will remain during all its schooling a gifted pupil although timid and awkward, often fleeing the contact of the other children. It is not ten years old when the Russian revolution bursts, creating within its family and of the Jewish minority of which she forms part the hope to finally see ceasing discriminations of which she is the object under the mode of the tsar Nicolas II.
After having finished its secondary studies at the thirteen years age, Lev hopes to be able to continue with the Faculty of Science of the university of Bakou but under the pressure of his ⁄ her father, and with its great despair, it is registered at the institute of the high economic studies of this same city. At the end of one year, while being able more, he refuses to continue and obtains from his father to go to study sciences at the university where he is registered in 1922 in mathematics and physics, becoming thus youngest of the students.
Two years later, its licence out of pocket, it obtains heats recommendations of its professors in order to continue its studies at the university of Petrograd. In spite of the disturbed political situation of the USSR of then, it finds on its arrival in 1924 an environment favorable to the intellectual blooming of the young scientists. Soviet capacity maintaining still at that time a progressist attitude with respect to sciences, seeing in it at the same time means of promotion of its ideology and combat of the religions.
Within this university, Landau binds quickly friendship with George Gamow and is seen quickly affublé of the nickname of dau which will follow it all its life. It thus begins its thesis in 1926 at the institute physico-technique of Leningrad and publishes its first article devoted to with the spectral analysis of the diatomic molecules. Its reputation of then the fact of passing for an eccentric, readily rebellious, even insolate but always charming, because at the same time awkward and timid. From the political point of view, Lev is then a convinced and enthusiastic revolutionist, being regarded as an authentic Marxist. In addition admiror of Trotsky, it worries about the rise to the capacity of Stalin and the emergence of a repressive and suspicieux political power.
After months of waiting, Landau obtains in 1929 a purse of the Soviet government as well as Rockefeller Foundation in order to go to study the physique abroad one year. It does not have whereas 21 years, but can be prided on a considerable scientific work, treating statistical and quantum physics in particular.
Its stay in Europe starts with Gottingen where he answers an invitation of max Born. At the end of a few weeks, it goes to Leipzig to follow the courses of Werner Heisenberg and is quickly pointed out for its intrepid and voluntary character. Little time after, it leaves for Copenhagen where it meets Bohr, of which it will be then always regarded as a disciple. He will go back to Copenhagen in 1933 and 1934. Its tour then leads it to Cambridge where he works under the direction of Paul Dirac and in Zurich with Wolfgang Pauli.
Pram regains Leningrad in 1931 and then notes a material change in the attitude of the Soviet government towards the Russian scientists. Those had indeed up to that point been able to work in a climate of relative freedom, the mode recently created seeking to be established a certain international legitimacy via the fame of its scientists. Beginning of the year 1930 is characterised on the contrary by a strong political will of the USSR to modify the ideology of its citizens, including the scientists.
In 1932, Landau settles in Kharkov, where one entrusts to him the direction of the theoretical section of the new Institute physico-technique of Ukraine. It is received science doctor in 1934 without to have had to support its thesis and is named with the pulpit of general physics of the university of Kharkov in 1935. In 1937, at the request of Pyotr Kapitsa, it settles in Moscow, where it is named by this one with the head of the theoretical section of the institute of the physical problems builds little front time. This nomination falls at point named for Landau, Moscow having replaced since a few Leningrad years like centers Soviet science. But its satisfaction lasts only a time, the end of the year 1930 is one difficult period for Soviet, the Stalinist purgings plunge the population in fear and suspicion.
The morning of 28 April 1938, a limousine penetrates in the court of the institute of the physical problems. A man as a civilian in fate and sounds with the door of the number two, the flat of Pram. This one is then brought to Boutyrskaïa, one of the many political prisons which Moscow account. It is announced to him that he is condemned to ten years of prison under the current charge at that time of espionage to the profit of the Nazi Germany. There remains one year in cell. Kapitsa succeeds in making it release in April 1939, while intervening directly with Molotov. Pram leaves prison émacié, seriously sick and mentally destroyed. Semi-serious semi-ironic, he will say this period later that it was not completely lost for him since he not learnt how to make head a very great number of complex calculations, the walls of its cell being used to him as imaginary black board.
He goes back to work as of his coming out of prison and finished an important study on the polarisation of the free electrons. There takes again its hierarchical and scientific position within the Institute of the physical problems but remains suspect with the eyes of the mode. This suspicion, maintained by the fact that Landau was never member of the Communist party, somewhat slowed down its entry with the Academy of Science of the USSR. After the supports and pressures of certain influential scientists, Landau made there its entry in 1945 without being present on the list of the central committee nor to be last by the intermediate stage of corresponding member.
As from 1949, Landau is attacked in collaboration with Evguéni Lifchitz, with a monumental work : its famous course of theoretical physics in ten volumes.
It is victim of a serious car accident on 7 January 1962, of which it will never recover from the after-effects to the level of its brain will modify its personality and will destroy its capacity to make physics.
Publication
Lev Landau is the inspiring author ⁄ of a course of theoretical physics written with the collaboration of its pupil Evguéni Lifchitz. This course is published in 10 volumes by the Mir editions. Because of its premature death, Landau did not take part in the drafting of volumes 4,9 and 10
Volume 1 : Mechanics, (4e édition, 1982), ISBN 5-03-000198-0.
Volume 2 : Theory of the fields (4e édition, 1989), SBN 5-03-000641-9.
Volume 3 : Quantum mechanics (3e édition, 1975), ISBN 5-03-000199-9.
Volume 4 : Quantum electrodynamics (2e edition, 1989), ISBN 5-03-000642-7.
Volume 5 : Statistical physics (I) (3e edition, 1984), ISBN.
Volume 6 : Mechanics of the fluids (2e edition, 1989), ISBN 5-03-000644-3.
Volume 7 : Theory of elasticity (2e edition, 1990), ISBN 5-03-000645-1.
Volume 8 : Electrodynamics of the continuous mediums (2e edition, 1990), ISBN 5-03-000646-X.
Volume 9 : Statistical physics (II) (1990), ISBN 5-03-000647-8.
Volume 10 : Physical kinetics (1990), ISBN 5-03-000648-6.

Wilhelm Röntgen



Birth date : March 27th, 1845
Birthplace : Remscheid, Kingdom of Prussia
Go back to death : February 10th, 1923
Place of death : Munich, Germany
Nationality : German
Fields of application : Physics
University : University of Strasbourg, University Louis-and-Maximilien of Munich
Diploma : Graduate of federal Polytechnic school of Zurich
Famous : X-ray
Distinctions : Nobel Prize of physique 1901
Wilhelm Conrad Röntgen is a German physicist. He discovered x-rays, which was worth to him to receive the first Nobel Prize of physics in 1901. He received the Rumford medal in 1896.
Biography
Physicist, born in Lennep in Allemagne.Il studied in Zurich, and became professor of physics in Strasbourg (1876-1879), in Giessen (1879-1888), Wurzburg (1888-1900) and Geneva (1900-1920). In 1895, he discovered electromagnetic rays which he called This discovery x-rays. was worth to him to receive the first Nobel Prize of physics, in 1901.
Only sons of Friedrich Röntgen, manufacturer of textile and Charlotte Constanze Frowein, it is born on March 27th, 1845 in Lennep, in the current commune of Remscheid, Rhineland-of-North-Westphalia, Germany). At 3 years, its family moves in Apeldoorn with the Netherlands, native land of her mother, for financial reasons. It enters to the institute of Martinus Hermann van Doorn, a boarding school. Although it does not seem to have any particular aptitude, it likes nature and the walks in forests, it seems very gifted to manufacture mechanisms, predisposition which it will keep all its life.
In 1862, allowed at the technical training school of Utrecht, it is expelled by it : it is shown to be the author of a caricature of one of its professors. In 1865, he studies physics at the university of Utrecht. He does not have the level to be student regular : he then passes the examinations of entry to the federal polytechnic school of Zurich to study in mechanical engineering. The teaching of its professors Kundt and Clausius will mark it. In 1869, it supports its thesis of physics and becomes the assistant of Kundt. It follows it around Wurzburg and three years later towards Strasbourg.
January 19th, 1872 with Apeldoorn, he marries Anna Bertha Ludwig, girl of an innkeeper of Zurich which he had met in the establishment held by his father. They do not have children but adopt in 1887 Josephine Bertha Ludwig, the 6 years old girl of the brother of Anna.
In 1874, it is university lecturer at the university of Strasbourg and in 1875, it is promoted professor with the academy of agriculture of Hohenheim in Bade-Wurtemberg. In 1876, it goes back to Strasbourg as professor of physics and three years later it accepts the pulpit of physics of the University of Giessen.
Work
The first article of Röntgen is published in 1870 about the specific heat of gases and is followed a few years later by an article on the thermal conductivity of the crystals. He studies other fields of physics, such as the electric properties and other characteristics of the crystals, the influence of the pressure on the index of refraction of various fluids, the modification of the plans of the light polarized by magnetic influences, the variation of the functions of temperature and compression of water and other fluids and the phenomena which accompany spreading out by oil on water.
The name of Röntgen is however mainly associated with its discovery with rays which it names x-rays. In 1895, it studies the phenomenon of the passage of an electric current through a gas under low pressure. Experiments in this field had already been achieved by J. Plucker (1801-1868), Eugen Goldstein (1850-1931), Sir William Crookes (1832-1919), H. Hertz (1857-1894) and pH. von Lenard (1862-1947). Work of Röntgen on the cathode rays brings it to discovered of a new type of rays.
The evening of November 8th, 1895, Röntgen observes that with the discharge of a tube, completely coated with black paperboard, sealed to exclude from it any light and this in a darkroom, a covered paperboard on a barium platino-cyanide side becomes fluorescent when it is struck by the emitted rays of the tube, and this until a distance of two meters. During subsequent experiments, it places various objects between a photographic plate and the radiation source and it realizes that they have a variable transparency. It tests then with the hand of his wife placed on the course of the rays. With the development, he realizes that the image is the shade of the bones of the hand of his wife, his alliance being visible there. The bones are surrounded by a half-light which represents the flesh of the hand, the flesh is thus more permeable with the rays. Following other experiments, Röntgen notes that the new rays are produced by the impact of the cathode rays on a material object. Because their nature is still unknown, it gives them the name of x-rays Later., max von Laue and its students will show that they are of electromagnetic nature, just like the light, and differ only by one plus high frequency.
This discovery causes in the researchers a sharp emulation, which will lead in France to the business of the rays NR.
Honors and recognitions
Röntgen was famous of sound living and after his death. In several cities of the streets bear its name. It had several prices and medals like several honorary doctorates. He was honorary member several companies in Germany and elsewhere the list of all its distinctions is long. Despite everything these honors, Röntgen remained a humble and hesitant man. All its life it preserved its love for nature. It passed the majority of its estival holidays to Weilheim, the foot of the Bavarian Alps, where it accommodated his friends, and made excursion in mountain. He was a good mountain dweller, and he has some times be in perilous situations during the practice of this activity. He was pleasant, courteous and always seemed to be concerned with comprehension and opinions of the others. Obstructed to have an assistant, he preferred to only work. He built the majority of the apparatuses which he used, sometimes with a great ingeniousness and a great talent of experimenter.
He accepted the Nobel Prize of physics in 1901 in recognition of the extraordinary services which he rendered while discovering the remarkable rays which were named thereafter in its honor.
In 1914, it was one of the signatories of Proclamation of the 93 supporting the militarism of the empire of Germany.
Four years after the death of Anna, Röntgen dies in his turn, on February 10th, 1923, in Munich, of a cancer of the intestine, which does not seem however to have any relationship with its scientific activities, Röntgen having been one of the first to use lead shields systematically in order to protect itself from these rays.

John William Strutt Rayleigh



Birth date : November 12th, 1842
Birthplace : Landford Grove (Essex, the United Kingdom)
Death : June 30th, 1919
Place of death : Witham (Essex, the United Kingdom)
Nationality : English
Fields of application : hydrodynamics, acoustics, Thermics, mathematical theory of elasticity
University : Trinity College (Cambridge), Cavendish Laboratory
Diploma : Trinity College (Cambridge)
Famous for Rayleigh diffusion, theory of the convection, Quotient of Rayleigh
Role : active member of the scientific company
Distinctions : Royal Medal (1882) - Medal Copley (1899) - Medal Rumford (1914, 1920) - Medal Matteucci (1894) - Medal De Morgan (1890) - Nobel Prize of physics (1904)
John William Strutt, third baron Rayleigh, more known under his title Lord Rayleigh was an English physicist. He is prize winner of the Nobel Prize of physics of 1904.
Its life
After some voyages in Europe and to the United States, it occupies a post of researcher in Trinity College of 1866 to 1871. Its work is temporarily suspended during the conflict free-Prussian of 1870, by his impact on the family of John William, however little implied.
In 1871, it Marie with Evelyne Georgiana Mary Balfour, girl of James Maitland Balfour and his White wife, girl of the second marquis de Salisbury.
With died of his father in 1872, it takes its succession and becomes baron Rayleigh, third of the title, and devotes an important part of its time to the management of the field. In order to be able to devote itself to science, it gives up this responsibility with his young brother in 1875.
In 1879, it accepts the vacant place left in Cavendish Laboratory of Cambridge by the disappearance of Maxwell.
As from 1884, it mainly continues its research in its field of Terling where it installs a laboratory.
With the dires of its compatriots, it is one of very rare noble of high ranking to be become famous for scientific discoveries.
Its work
The first work of Lord Rayleigh consists of the mathematical approach of optics and the vibratory systems, then extend to practically all physics from the time : the sound, vibrations, vision of the colors, electrodynamics, electromagnetism, the light diffraction, the mechanics of the fluids, viscosity, capillarity, elasticity and photography.
Among his first work, one notes a theory of the resonance which made of him an authority in acoustics.
Its treaty on the sound, writing at the time of a cruising on it and enriched by updates, had value of reference a long time.
In 1871, it provides an explanation of the color of the sky by connecting it to the diffusion of the light by the molecules of air.
In the years 1880, it contributes to the definition of the fundamental units of electricity : the amp, the Ohm and the volt.
In 1892, it determines the density of nitrogen. In 1894, he discovers argon with sir William Ramsay.
Nobel Prize of physics of 1904
In 1892, Rayleigh succeeds in determining dimensions of certain molecules by the study of the thin layers. Examining a report ⁄ ratio of experiment of Cavendish gone back to 1795, whereas he studied the density of gases in collaboration with Ramsay, Rayleigh discovers new constituting air, argon. Ramsay receives for this discovery the Nobel Prize of chemistry of 1904, whereas Rayleigh receives the Nobel Prize of physics of 1904 for its studies of the density of the most important gases and for the discovery of argon in bond with these studies.
The law of Rayleigh-Jean
Interest shown of Rayleigh for optics, as for all the undulatory phenomena in general, the conduit with research in spectroscopy. It establishes with the mathematician and astronomer James Jeans, by using for that statistical mechanics, a law theoretical, known under the name of law of Rayleigh-Jean, which expresses the distribution of the energy radiated by the black body according to the wavelength, valid for the big wavelengths. By introducing the quanta, max Planck will determine the general law later a few months, by making the synthesis of work of Rayleigh and Wien.
Member, since 1876, of Royal Society, he becomes about it the secretary of 1885 to 1896, then the president. During fifteen years, it is to advise of Trinity House, organism in charge of the installation and the maintenance of coastal installations.
It contributes largely to the creation of the National Physical Laboratory of Teddington, of which it chaired the executive council.
He was also chancellor of the University of Cambridge.
Publications
Its writings are recognized of very editorial high-quality. He in particular left :
The theory of the sound) in 2 volumes (1877-1878)
Scientific Papers gathering a great number of its studies in six volumes (of 1889 to 1920)
Several articles of Encyclopédia Britannica.
Distinctions
Lord Lieutenant of Essex of 1901 to 1892.
1896 to 1919 to advise scientific at Trinity House.
Order off Merit in 1902.
Named Chancellor of the University of Cambridge in 1908.
Member of Royal Society secretary, then president of 1905 to 1908.
Medals Royal 1882), Copley 1899 and Rumford 1914,1920 of Royal Society.
Matteucci medal of the Company Italian of Sciences 1894.
Faraday Lectureship of Royal the society off chemistry 1895.
Medal De Morgan of London Mathematical Society in 1890
Nobel Prize of physics in 1904, for its work concerning the density of gases of the air and the discovery of argon.
Its memory
A unit of luminous intensity, the Rayleigh, bore its name, which remains also attached to the surface seismic wave, the wave of Rayleigh.

Johannes Rydberg



Birth date : November 8th, 1854
Birthplace : Halmstad
Go back to death : December 28th, 1919
Place of death : Lund
Studies : university of Lund
Profession : professor at the university of Lund
Fields of application : optical physics and spectra
Johannes Rydberg was a Swedish physicist. It is especially known to have conceived the formula of Rydberg in 1888 to predict the wavelengths of the photons emitted by changes of the energy level in an atom.
The constant physics known as constant of Rydberg is named in its honor, just like the Rydberg unit. The excited atoms with principal quantum numbers very high, represented by N in the formula of Rydberg, are called the atoms of Rydberg and a crater of the Moon is also called Rydberg in its honor.
He worked at the University of Lund during all his career. He is elected foreign member of Royal Society on June 26th, 1919.

Hans Christian oersted



Birth date : August 14th, 1777
Birthplace : Rudkobing (Denmark)
Death : March 9th, 1851
Place of death : Copenhagen (Denmark)
Nationality : Dane
Fields of application : Physics
University : Royal academy of sciences of Sweden, technical University of Denmark
Graduate of the university of Copenhagen
Famous : Discovered interaction between magnetism and electricity, Unit oersted
Distinctions : Medal Copley (1820)
Hans Christian oersted is a Danish physicist and chemist. It is at the origin of discovered interaction between electricity and magnetism.
Biography
Interested as of its more young age by chemistry and the natural history, but also by the literature, it was directed, under the influence of his father apothecary, worms of the studies which made of him a pharmacist in 1797 whereas it had just been his twenty years old. Three years later, it obtained a diploma of medicine which could have ensured its future in the medical community to him. But its passion for chemistry, in particular for the electrochemical forces and its growing interest for the philosophy of Nature, were the releases of all its reflections and expliquents of good part why it was interested in work of Ritter on the galvanism.
Of return of its stay of study in Paris where it met inter alia Cuvier and Biot, it worked in close cooperation with Ritter and became, after the death of this last, its spiritual heir. It is made foreign member of Royal Society in 1821.
It was influenced by the German thought, in particular Emmanuel Kant.
Discovered interaction electricity and magnetism
In April 1820, at the time of a course on the electricity which it made with its students, it discovered the relation between electricity and magnetism in an experiment which seems to us today very simple.
It showed, by the experiment, that a transporting wire of the current was able to make move the magnetized needle of a compass. There could thus be interaction between the electric forces on the one hand and the magnetic forces on the other hand, which was revolutionist for the time.
oersted did not suggest any satisfactory explanation of the phenomenon, nor did not try to represent the phenomenon within a mathematical framework. It however published on July 21st, 1820 its experimental results in an article of 4 pages in Latin entitled. Its writings were represented and diffused in the whole of the European scientific communities and its highly criticized results.
Amp took note of its in September 1820 results and quickly developed the theory which was going to allow the emergence of electromagnetism. The success of this theory contributed to the recognition of oersted, as well in the scientific community as among its fellow-citizens.
Royal Society decrees the Copley medal to him in 1820.
In 1819, he discovers piperin.
In 1825 it produced for the first time of aluminum.
He is the founder of the technical University of Denmark.
He was freemason
Posterity
Two hundred and thousand people attended her burial. The Danish population lived its loss like an major event and like a national mourning because, thanks to its discovery and to its gifts of speaker, it had contributed to give an active and positive image of Denmark.
However, oersted was the first nobody to discover that electricity and magnetism were connected. An Italian clerk, Gian Domenico Romagnosi, were advised 18 years before. It published its discovery in a local newspaper, and she was ignored scientific community.
Since 1936, the American Association of the professors of physics decrees the Oersted medal, which rewards for the notable contributions in the teaching of physics.
The first Danish satellite was baptized of its name because of its mission which is mainly to measure the terrestrial magnetic field.

Felix Savart



Birth date : June 30th, 1791
Birthplace : Wall (France)
Death : March 16th, 1841
Place of death : Paris (France)
Nationality : French
Fields of application : Medicine, physics
Re-elected : Sonometer, law of Biot-Savart
Felix Savart is a French doctor surgeon and physicist, inventor of the sonometer, a toothed wheel who bears his name and of the polariscope. He translated the Treaty De Medica de Celse. He provided the foundations of molecular physics and its writings are joined together in Annals of physics and chemistry. With the physicist Jean-Baptiste Biot, it measured the magnetic field created by a current and formulated the law of Biot-Savart.
He also studied the properties of the vibrating cords and built a violin of trapezoidal form which is always preserved in France in the collection of the Polytechnic school.
He was member of the Academy of Science, elected in 1827, and holder of the pulpit of general and experimental physics of the Collège de France, named in 1836, succeeding Andre-Marie Ampère and preceding Henri Victor Regnault. He is elected foreign member of Royal Society on May 30th, 1839.
Its name was given to a measuring unit of the musical intervals : the savart.

William Gilbert


William Gilbert
birth date : May 24th, 1544
birthplace : Colchester, in England
death : December 10th, 1603
This first doctor of the Queen Elizabeth I Re then of Jacques I er révêle a physicist pioneer, a true scientific researcher who discovers and publishes the laws in the fields of magnetism and electricity.
Its first work was De Magnete, Magneticisque Corporibus and of Magno Magnete Tellure published in 1600. In this book it describes many its experiments magnetic with a ground model called terrella.
In this book which develops an overall theory of the terrestrial magnetism while drawing from the old man knowledge of the blacksmiths colchestriens, the editor notices clearly and smoothness :
rules of attraction and repulsion of the magnets by their poles
the magnetization of a soft iron bar in a magnetic field
the influence of heat on the magnetism of iron
Maintaining its assumption starting from precise experiments, he proposes to compare the Earth to a magnet and concludes that is the reason for which the compass indicates north.
In the same work, he also studies static electricity by using amber, as amber names also elektron in Greek, Gilbert thus decided to call it electricity. Among the first concepts of electricity, the physicist gives a list of the electrifiable bodies by friction.
A magnetic unit of force is called the Gilbert in his honor.

Edwin Herbert Hall



Born on Tuesday, November 7, 1855. Died on Monday, November 20, 1938.
Edwin Herbert Hall is an American physicist who discovered the Hall effect in 1879, which is the main theme of its thesis of doctorate.
He attends Johns Hopkins University in Baltimore. During its doctorate, he discovers the Hall effect.
He is recruited as professor of physics at the Harvard university in 1895, withdraws himself in 1921 and dies in Cambridge. He undertook search in thermoelectricity and wrote many works of physics.
The traditional Hall effect was discovered in 1879 by Edwin Herbert Hall : an electric current crossing a material bathing in a magnetic field generates a tension perpendicular to those.
Under certain conditions, this tension grows by bearings, effect characteristic of the quantum physics. The Nobel Prize of physics was allotted in 1985 for the whole quantum Hall effect and in 1998 for the fractional quantum Hall effect.

Heinrich Rudolf Hertz



civility
Birth : 22 February 1857 Germanic Hamburg Confederation
Death : Bonn 1 January 1894 Worsens German
Residence : Karlsruhe then Bonn
Nationality : allemande
field : Electromagnetism, undulatory physics, analytical mechanics
University : Technische Hochschule of Karlsruhe, University of Bonn
Graduate of Institute of Physics of the Humboldt university of Berlin
Famous for Hertzian waves, hertzian contact
Distinctions : prize winner of the Rumford Medal
Heinrich Rudolf Hertz (born on 22 February 1857 in Hamburg, Bonn on 1 January 1894), was an engineer and German physicist.
Biography
22 February 1857 Hamburg (Germany) birth of Heinrich Hertz, wire of Gustav Ferdinand Hertz, lawyer and of Anna Elisabeth Pfefferkorn-Hertz.
1863-1872 Raise studious school of Dr. Richard Lange
1875 After studies impassioned near tutors he becomes graduate and goes to Frankfurt to work during one year in the service of Public works
1876 Student Polytechnic Institute of Dresden
1877 Military service in Berlin
1878 Student at the University of Munich
1879 Student in Berlin, raises of Gustav Kirchhoff and Hermann von Helmholtz at the Institute of Physics
1880 Doctor in Physics then attending the Institute of Physics
1883 Lecturer at the University of Kiel. Carry out search on electromagnetism.
1885 Professor in Technische Hochschule of Karlsruhe
1886 Marriage with Elisabeth Fraud
1887 Study of the various theories of Maxwell, Weber, Helmholtz. Realisation of an oscillator.
1888 Work and discovered electromagnetic waves in the air
1889 Professor and researcher in Bonn
1890 Travel to England, prize winner of the Rumford Medal.
1erjanvier 1894 deaths in Bonn of a degenerative disease (cancer)

Guglielmo Marconi



Civility
Guglielmo Marconi
Birth : Bologna 25 April 1874
Death : 20 July 1937 in Rome
Nationality : Italy
Profession : Physicist, inventor and business man
Distinctions : Nobel Prize of physique 1909
Marconi and Karl Ferdinand Braun are co-winners Nobel Prize of physics of 1909 in recognition of their contributions to the development of wireless-aware telegraphy.
Biography
Guglielmo Marconi was born close from Bologna in an easy family, second wire of Giuseppe Marconi, an Italian owner, and of an Irish mother, Annie Jameson, grand-daughter of the founder of Distilling Jameson Whisky. It made its studies in Bologna in the laboratory of Augusto Righi, in Florence, the Cavallero Institute and, later, Leghorn. Child, it did not work well at the school. Baptized according to the rite of the Catholic church and Roman, he was also member of the Church Anglican, within which it Maria, although he received a catholic cancellation of his marriage.
Chronology
1895 : Experiments on the waves discovered by Hertz seven years before. It reproduces the hardware used by Hertz by improving it with a coherer of Branly to increase the sensitivity and the antenna of Popov. After its very first experiments in Italy, it carries out in the Swiss Alps with Salvan a connexion of 1,5 km during the summer 1895. This experimentation however had been given in doubt on the Italian side before being officially recognised by the International union of telecommunications (Inheritance of telecommunications UIT in September 2008
1896 : Fault of being followed by its compatriots, it leaves for England, continues its experiments and deposits a patent.
May 1897 : First communication in Morse with more than 13 km between Lavernock Wales and Brean England over the Bristol-board Channel.
July 1897 : return in Italy where the Italian royal navy allows him to carry out tests between a fixed transmitter located in the arsenal of San Bartolomeo with Spezia (Italy) and a receiver on board the tractor San Martino. The antenna used was 34 m length. A range of 18 km was reached. Creation of the company Wireless Telegraph and Company Signal.
1898 : Opening of the first factory of radios in the world, Chelmsford, England.
1899 : First connexion transmanche by radio. The transmitted message is a telegram of homage to Edouard Branly, inventor of the coherer, without which this connexion would not have been possible.
1900 : Name change of the company which becomes Marconi Wireless Telegraph Company. Deposit of the patent n° 7777 on the use of tuned circuits allowing the use of several frequencies.
1901 : Connexion between Corsica and the continent. First transatlantic connexion between Poldhu Cornouailles and Newfoundland in Canada. In addition to its spectacular character, this experiment of emission made it possible to highlight the phenomena of propagation at long distance in low frequency and on average frequency.
1902 : Invention of a magnetic detector.
1903 : demonstration of wireless-aware telegraphy at Royal the Institution, during which its rival Nevil Maskelyne hacke the performance.
1904 : Experiments on the directivity of the antennas and use of the diode of Fleming as a detector.
1909 : prize winner of the Nobel Prize of physics with Ferdinand Braun.
15 April 1912 : Shipwreck of Titanic. All those which were saved it were thanks to a man, Mr. Marconi and with his marvellous invention.
1918 : Franklin medal for the application of the radio waves to the communications.
1920 : First radio broadcast of Chelmsford, England.
1922 : First radiophonic regular emissions in the world since Writtle, close to Chelmsford, England.
1922 : Foundation of the BBC by a consortium including G. Marconi in particular.
1924 : Development of the world radiocommunications on short waves by reflexion on the ionised layers of the upper atmosphere
1932 : Tuning of the radiotelefony on waves ultracourtes.
20 July 1937 : Death of Marconi to Rome and birth of the radar.
Scientific work
Hertz made its thesis of doctorate under the direction of Hermann von Helmholtz. It is while trying to connect the interference rings formed between two lenses of glass that he sought the spherical deformations of two bodies put in contact under a given force, by supposing their elastic linear behaviour. It analytically solved this question during the holidays of Christmas 1880, and published his results in 1881. The problem of the resilient contact of two spheres remains only solved to date analytically. It finds many applications, particularly in the tests of hardness per indentation.
But its contribution essential with physics remains the experimental checking in 1887 of the theory of James Maxwell of 1864, according to whom the light is anything else only one wave electromagnetic.
It is in Karlsruhe that using an oscillator (known as oscillator of Hertz, composed of a spark-gap acting between two hollow brass spheres) it highlighted the existence of other electromagnetic waves, these nonvisible. It showed that these new waves, likely they as to be diffracted, to be refracted and to polarise, were propagated at the same speed as the light. 13 November 1886, it carried out the first connexion by electro-magnetic wave between a transmitter and a receiver. These results opened the way with wireless-aware telegraphy and radiophony. For this reason, the radio waves are known as Hertzian waves, and unit S.I of measurement of the frequencies is the hertz (name into tiny because it acts of a measuring unit, on the other hand the symbol is Hz).
Hertz discovered in 1886 the photoelectricity : a metal plate being subjected to a light will emit electrons, of which the quantity will depend inter alia luminous intensity. Its assistant Wilhelm Hallwachs will continue search in this field, discovering in 1887 the Hallwachs effect, which was to play a central role on the assumption of the quantas of light formulated by Albert Einstein in 1905.

Gaston Planté



During its whole life, devoted to the scientific speculations, he did not request any official place, he did not aspire to any honor. Born fortunate parents in Orthez (the Low-Pyrenees), on April 22nd, 1834. , it was fixed at Paris about the fiftieth year, street of the Cherry orchard in the district of the Bastille, took its university degrees in mathematics and in physics in the Sorbonne and attache shortly after with the national Academy of Arts and Métiers as preparer of Edmond Becquerel, it began his first research on the voltaic polarization which led it to its brilliant discovered electric fencer (1860).
Since 1842, the English physicist William Robert Grove had noted the instability of the electrolytic decomposition of water. The oxygen and the hydrogen, which are released with each of the two poles of the apparatus, recombine slowly, indeed, if one gives up them in the presence of the platinum electrodes having been used to obtain them. However the recombining of these two gas elements takes place while restoring with the known as electrodes of the current that those one T spent to produce it. Gaston Planté took again the question in substituent various metals with platinum and replacing water by acid solutions. He observed whereas by using lead electrodes and very diluted sulphuric acid, one obtained a current much more intense than that provided by the machine of Grove.
This secondary pile, as it called it, was, ultimately, a reversible machine, which discharged by producing current absorptive later on during its regeneration. During the period of load of this accumulator oxygen was fixed on the positive electrode in the form of oxides, while lead, dissolved in the electrolyte, settled on the negative electrode which took flax spongy aspect. During the discharge, this pulverulent lead turned over to the electrolytic solution with part of the oxygen of the positive plate.
Then, continuing to study the phenomena which occurred in this invaluable energy tank, the sagacious inventor saw that by increasing the thickness of the layer activates lead blades, one improves the electric capacity. The current manufacture of the accumulators is still inspired by this observation made at one time by Planté. On a side, one prepares lead oxide pastilles, which one places in the cells of the positive plates and which is peroxidized with use. In addition, one carries out negative plates which one recovers of spongy lead before their : final assembly.
Thus, right from the start, electrician illustrates it had known to extract from his invention the maximum of effectiveness. In vain, since three quarter centuries, its successors sought to improve his work. Edison itself hardly succeeded there : its accumulator has electrodes of iron and of nickel with alkaline electrolyte is not more resistant than that to lead. As for the attempts made to use halogenous iodine or other bodies, they had only transitory successes. If these types of reduced accumulators seem very practical, the chemical reactions which take place depreciate them later on there rather quickly and their reversibility proves quite lower than that of the Planté accumulator.
Remainder, the sagacious researcher was not satisfied to have built an almost imperfectible machine, it made use of it to make new scientific conquests. In its apartment of the street of the Cherry orchard transformed into laboratory, it produced its famous rheostatic machine, association of an accumulator battery of 800 couples with plate condensers of mica, allowing him imposing electric demonstrations (1877). It could thus reproduce artificially various atmospheric phenomena, inter alia northern lights and the lightning in ball.
I remember, wrote Gaston Tissandier, to have often attended formerly the imposing experiments of Gaston Planté, they were not without danger, because the electrodes which it handled had been able to strike of dead the unfitted experimenter with his 100.000 V of tension! This device, somewhat modified and considerably undoubtedly amplified, made it possible to obtain recently, in laboratories French and American, sparks of 3 million V. By joining together by a wire the two reinforcements of such spark-gaps, one manages to produce some 25 meters length flashes, reduced imitations of the atmospheric discharges per stormy weather.
At all events, with this rheostatic machine and his various Research on electricity (1879), Gaston Planté opened new horizons and the French company of the electricians proposes not without reason, to republish this book, become today of an extreme scarcity. With discovered of Volta, the Franklin ones, Amp and other initiators, Planté had known to add the fertile principle of the reversibility of the electric phenomena.
The scientist electrician had, moreover, a vast scholarship. If he lived modestly on this ground, if he did not make there noise contrary with those which pass there with crash and do not leave after them anything durable according to the words of one of its biographers, he sowed there the germ of a fertile harvest for the future. Continuing its patient labor until his death, which has occurred on May 21st, 1889, in its country house of Bellevue, close to Paris, it spent its days, either in its cabinet of physics, or in its library, with reading not only the scientific publications, but still works of the philosophers and the large Greek, Latin or French literary men, or in company of his ⁄ her brother celebrates it musician Francis Planté, or in company of parents or close friends sorted on the shutter.

Alessandro volta



Nowadays, which among us forever used, considering or heard of the accumulator which makes function most of our portable devices. That it is for the leisures or work, the pile is almost essential. Eh well, this invention let us owe we it in Alessandro Volta, inventor of the first pile.
Volta was born with As in 1745, it is resulting from a noble family that the bad luck and misfortunes impoverished. In 1758, Volta entered to the college of the Jesuits where one taught the Greek, Latin and Rhetoric to him. Already at that time, it appears very brilliant. Volta was a poet lover of nature. Its poems, written for the Latin or Italian majority, were so good that the Jesuits asked him to enter the Order. Volta refused, it was too independent; he wanted to preserve his freedom and he did not want to yield with a so severe discipline.
About 1775, Volta began its first work on the electric phenomena. It developed the electrophorus which made it possible to multiply electric charges and the electroscope which made it possible to detect the potential differences that one indicated thereafter in Volt in his honour. Then, it was named professor of experimental physics at the School of Like. Volta is bored, its work does not satisfy its love for nature. It starts again to go for long walks in forest. During one of its walks, it observed that a certain gas was released from a marsh. After having studied this phenomenon and makes several experiments, it did not have there more doubt : a new gas had been born, methane. This gas is formed by the organic matter decomposition. Thereafter, he discovered Eudiomètre with water which makes it possible to analyse the composition of the air.
Volta becomes increasingly important and in 1777, it will carry out several important meetings of which that of Daniel Bernoulli, one of the inventors of the kinetic theory of gases and the hydrodynamics. Before its installation in Geneva, it met the physiologist Albrecht Von Haller.
In 1779, it is named with the pulpit of experimental physics of Pavia. Since it became increasingly large and important, certain jealous tried to drive out it of its station by writing in certain newspapers that it neglected its classes to be devoted more to its personal work. Following this work, in 1800, the first pile had been born.
Although Alessandro Volta is the inventor of the first pile, other researchers before him influenced. One of the researchers who influenced more Alessandro was Luigi Galvani, professor of anatomy at the University of Bologna. This one studied the effect of discharge produced by a generator on dead frogs.
The experiments of Galvani showed that the frogs had muscular contractions when one ran in the body of those an electric current produced by an electrostatic machine. Then, after several experiments, he discovered that the generator was only one accessory so that the muscles of frog contract. The muscles contracted only in contact with two pieces of metal. Its experiments also showed that the frog did not react in the same way in contact with all metals. Indeed, he noticed that the frog had very light contractions when one used the same metal to connect the two ends of frog and that these same contractions were definitely more marked when metals were different. After several tests, he concludes that the contractions were optimal when the frog was connected by a copper wire and a wire of zinc. All these experiments brought it to the conclusion which the electricity which made move frog was contained inside this one.
Volta was interested at once in the experiments of Galvani, and it started again each one of them exactly as Galvani had done them. After many observations, Volta rejetta conclusions emitted by Galvani; it showed that the convulsions of frog were not the product of electricity contained inside frog but rather the result of an external power source. It thus put forth the assumption that electricity was generated by the two metal plates. Its plates must then be put in contact with a wet conductor. Thus the experiments of Galvani answered the statement of Volta : ]two plates of metal (zinc and copper) joined together by a conducting liquid (body liquid of frog)_.
Starting from the results obtained in its searchs and those for Galvani, Volta produced the first pile. This pile was made up of different metal discs, that is to say zinc and copper. Between each superposition of disc, it had soaked one with them there with brine (H2O+NaCl) to lead the current. The first pile had been born.
Alessandro Volta interested the whole world by the discovery of its pile. The glory of this man was engraved forever in the history of electricity.
Several researchers studied the phenomenon of the pile of Volta and tried to improve it. Some discovered the illumination with arc which shows that electricity causes a kind of flash. They showed the phenomenon by connecting the two terminals of the pile to a piece of coal. But the most important discovery was the first electrolysis of the water which made it possible to identify the two components of water, that is to say oxygen and hydrogen. This important discovered was the work of Anthony Carlisle and William Nicholson. The electrolysis of water had been carried out before but it did not give the same result as with the pile of Volta. Indeed, the other attempts were carried out with a noncontinuous power source, the result of electrolysis was always a mixture and not of pure oxygen and hydrogen. With this discovery, one opened the gate with all kinds of electrolysis of which that of aluminium and copper.
Then, the first accumulators made their appearance. They were made up of several joined together voltaic piles. These accumulators were the first with being marketing. Nowadays, the piles are of better quality and are made up of more powerful metal. One of the principal defects of the pile of Volta was its sealing; the brine in which the pieces of paperboard were plunged ran pile. This problem is now solved because one replaces the brine by a more consistent gel.
In 1820, one discovered that the electric phenomena close were connected to the magnetic phenomena. This link was discovered when a scientist noticed that the needle of its compass changed direction when it moved it around a wire connected to the pile of Volta; all dependent on its position, the compass did not indicate the same direction. Imagine the importance of this discovery : the pupils of the whole world still study this phenomenon nowadays
In 1836, Daniell developed the first impolarizable pile, it was the beginning of our era.

Andre-Marie Ampere



Andre-Marie Ampère was born in Lyon on 20 January 1775 in a house from the Saint-Anthony quay from the parish from Saint-Nizier. his ⁄ her father, Jean-Jacques, trader then juge de paix and police officer of the canton of the Corn exchange, had married in 1771 Jeanne Desutières-Sarcey. The day before their marriage, it had bought in Poleymieux a field including/understanding a house of Master and an contiguous farm where André Ampère passed his childhood and his adolescence.
Jean-Jacques Ampere, enthusiastic disciple of Rousseau, took as a starting point the Emile to inform without constraints his son who "never went to school". He taught him itself Latin. As of the thirteen years age, the young Amp was impassioned for mathematics and composed a treaty of the conic sections while following its only inspiration. Struck by this precocity, a friend of its father, the Daburon abbot, gave him concepts of differential and integral calculus.
Endowed with an astonishing memory, Ampère studied in the alphabetical order the Large Encyclopaedia of Diderot and Alembert, of which it still knew whole chapters at a advanced age.
In 1793, the Ampère family was struck pitilessly by the tragic death of her chief. The marked town of Lyon of federalism was besieged by troops of Convention national, taken and condemned to lose its name to become "freed City". Like so much of other citizens, Jean-Jacques Ampère who had continued to exert his functions during the seat, was condemned to the capital punishment and was carried out on 25 November. Two days before its death, it had been able to write with his wife an admirable letter where this prophetic sentence was raised : "As for my son, there is not only I do not wait of him. "
After one year of prostration where its intelligence appeared to sink, Ampère composed of the poems epic, the tragedies. It met a girl "with the golden hair, with the eyes of azure", Julie Carron, whose family lived Saint-Germain, close to Poleymieux, which became his wife on 6 August 1799. One year later was born their son Jean-Jacques-Antoine who was to leave a famous name in the literature and the history.
In 1802, Ampère which had started to earn its living by giving lessons of mathematics, physics and chemistry in Lyon, obtains a post of professor at the central School of Borough-in-Bresse.
It then publishes its first important report, "Considerations on the mathematical theory of the play", which showed said it, that the passion of the play leads those which are devoted to it to an inevitable ruin. One then starts to notice it in the erudite spheres and one offers to him a post of professor with the new College of Lyon. Returned in its birthplace in 1803, Ampère is again struck cruelly by the death of its young woman, mined by a long illness.
Upset by this test, it leaves the region of Lion for Paris and becomes repeater at the Polytechnic school. At thirty-three years, it is named General inspector of the University. In 1809, he teaches the mathematical Analysis at the Polytechnic school. He enters to the Academy of Science in 1814 the section of Geometry.
A second unhappy marriage, soon followed by a separation, gives him a girl, Albine. The love life of Amp ends in the dream of a third union with an young girl whom it called dream "the constant friendship", according to a famous engraving, without a future. Amp will be devoted from now on to Science. Amp, said Paul Janet, "was man quite simply, with his loves and its pains, its alternatives of religious doubt and major faith, its heat with the work and its discouragements, and before all its impassioned search of the truth which is summarised in the desperate cry that he addressed to his friend Bredin : I find only truths, teaches to me the Truth".
Member of the Legion of honour, member of many learnt societies, the Great Amp, used by work, finished his life in Marseilles on 10 June 1836 during a university Inspection. He was buried there almost in the indifference. It is into 1869 that friends of its son transported his coffin to Paris, to let rest in only one tomb, with the cemetery Montmartre, Andre-Marie Ampère and her Jean-Jacques son who had just died by not leaving any descent.
The work of an exceptional scientific engineering
The work of Amp is important in many disciplines. In chemistry, it had major sights on the atomic constitution of the matter. In 1809, Gay-Lussac had noticed that the gas substances combine in always simple values their volumetric ratios (1, 2,3,4). Amp deduced from it that the number of molecules in the same volume of gas was constant whatever the gas (1814). Similar considerations had already been formulated in 1811 by the Italian scientist Avogadro. It is the law vogadro-Amp.
One also owes in Ampère, in 1809, the assumption of the existence of fluorine. Struck by the analogies between hydrochloric acid and the hydrofluoric acid, he concludes with the existence from an element that he calls "phtore". Amp will leave nevertheless in Humphry Davy, convinced of the accuracy of its sights after three years of correspondence, glory to announce in 1813 the discovery of this new element. An autobiographical note of Amp, in which he speaks about him with the third anybody, however establishes the anteriority of its discovery.
But it will be the electrodynamics which will be worth in Ampère of the uncontested honours and the glory, shared with the only Lord Kelvin, to give his name to the one of our seven fundamental units. The Danish physicist orsted publishes on 21 July 1820 his observation of the deviation of a needle magnetised in the vicinity of a fil conductor connected at the boundaries of a pile. This opuscule of four pages in Latin is spread in a few weeks in all Europe and the described experiment is repeated everywhere where one has piles. On 4 and 11 September, Arago presents the report of Oersted to the Academy of Science. At Ampère which attended the meetings, one of these fulgurating intuitions occurs then of which it is usual. It is thrown in multiple experiments on which its high mathematical culture enables him to base the theory of the electrodynamics.
It distinguishes the "electric tension" which appear between two bodies in charge of electricity, separated by nonconducting bodies, and the electric current which moves inside a closed circuit made up of conducting bodies. He affirms that the magnetic phenomena do not have an origin different from that of the electric phenomena, and that magnetism is produced by small electric currents circulating around the particles of the matter. It proves by many experiments this identity between magnetism and electricity, and reproduced in particular the effects of the magnets by "galvanic propellers" or "solenoids". He also discovers with Arago the electro-magnetisation of steel (permanent magnet) and the soft iron (temporary magnet or electromagnet). He shows finally that two electrical circuits can react one on the other without intervention of magnets. He states the laws of attraction and repulsion of these currents. All is known as in a few days. Its memories presented to the Academy of Science give a complete mathematical analysis of these phenomena, "only deduced from the experiment".

Thomas Edison



Thomas Edison was born in Milan, in Ohio in 1847. Wire of a second-hand dealer of origin Dutchwoman and a teacher of Scottish origin, nothing intended Thomas Edison to become inventor. He does not go to school : it is his ⁄ her mother who undertakes her education. At ten years, it installs a laboratory in the cellar of the family home; impassioned of mechanics, chemistry and physics, matters to which it is only initiated.
Newsvendor since the twelve years age, it creates a weekly newspaper in 1862,it names Large Trunk Herald. One of the vans of a train, placed at its disposal for the impression of its numbers, is used to him also as laboratory. It writes and prints itself its newspaper which it sells to the travellers. Having put fire at its truck-laboratory after an experiment which badly turned, it must seek another employment soon.
In reward to have saved the life of a child, one taught him telegraphy and he thus becomes operator of telegraph. This apparatus being very incomplete, it decides to improve it. Its first invention is a duplex telegraph which made it possible to transmit messages automatically, without the intervention of an employee.
In 1869, it succeeds in repairing the apparatus of telegraphy of the purse used to transmit the rates of gold. The company "Western Union" the recruiting as assistant. The business success of the telegraph multiplexing, being able to transmit and print the courses of the quoted values, makes it possible to the young man to create then to resell a small firm
The funds thus gathered, it creates in 1876, its own laboratory (in Menlo Park). The same year he invents the microphone with carbon cartridge which was an important discovery in the creation of the telephone.
In 1877, it completes the construction of a gramophone which could record the sound, thanks to a needle, on a cylinder covered with an aluminium foil. It concretizes the dream of the men thus : to reproduce the word. 19 December 1877, it deposits a patent for a transmitter and a telephone receiver, equipped with microphones with pellets of coal, essential components of any telephone.
Two years later, Edison presents its last invention as a public : a contituée electric bulb of a filament under a air space bell. January first, it thus illuminates the street, the library and the laboratory of Menlo Park with a dynamo and 40 bulbs with low tension. In October 1879, using capital advanced by the large financial ones, it founds its own company, Edison Electric Light Company, having for principal goal to manufacture bulbs.
Edison in front of a kinétographeEn 1878, Edison is made chevalier of the Legion of Honour and, in 1889, commander of the Legion of honour. In 1892, it is decorated with "the Albert Medal off the Royal Society off Arts" British and, in 1928, it receives the gold medal of the Congress for the development and the application of inventions which revolutionised civilisation during the last century.
4 September 1882, the first factory intended to produce electricity in the world is mise en service in the district of Wall Street. It supplies 1.200 lamps illuminant 85 houses, offices or shops. Other installations, more powerful, are create and less than one year later, more than 430 New Yorkean buildings will be lit by more than 10.000 bulbs.
In 1887, it settles in West Orange, in the New Jersey in order to increase its laboratory. One year later, after having received Eadweard James Muybridge, it develops the kinetograph and the kinetoscope, machines respectively making it possible to record and view individually called very short films "seen". The same year, it also improves the gramophone thanks to a diamond and disk-based system.
In 1893, after George W. Eastman and that Hannibal Goodwin made improvements to the kinetoscopes, Edison open the Parlours Kinetoscope, rooms where one could view (for 25cents) a series of images, thanks to these last apparatuses. With Dickson, its principal technician, it opens the first movie studios in order to feed the rooms of projection out of film and in 1903, it markets a named camera "Universal Projecting Kinetoscope", making it possible to record 12 images on film of 35mm.
In 1914, it produces first sound film by synchronising its gramophone and its kinetoscope and a year later, it also invents the first accumulator (alkaline accumulator nickel-iron)
Its others important discoveries : the machine to be roneoed, the microtasimeter (used for the detection of the changes of temperature) and a telegraph wireless-aware to communicate with trains.
At the time of the First World War, Edison conceived, built and made function of the chemical plants and in 1915, it was named president of the Advisory committee of the American navy.
He dies in West Orange on 18 October 1931, after having deposited on the whole 1.093 patents and employing more than 35.000 people in his factories.

Alexander Graham



American specialist in audiology, born in Scotland, it is known as inventor of the telephone. During two generations, its family was recognised like an authority in the field of elocution and the correction of the word. During their youth, Beautiful and his two brothers were involved to continue the profession of the family.
Alexander was the second of the three children of Alexander Melville Bell and Eliza Grace Symonds Bell. He attended the private school during one year, he spent two years to the Royal college of Edinburgh (where he was graduate at the 14 years age), he offered his services to some conferences at the universities of Edinburgh and London. He had its first professional station at the school of Mr. Skinner in Elgin in the county of Moray, where he taught the music and elocution with the children. In 1864, he became a Master resident with the Academy of Elgin S Weston House, where he undertook his first studies on the sound. Thus, he had become a teaching scientist.
In 1871, Bell spent several weeks to Boston, giving conferences to show the system of the visible word of his ⁄ her father, published in 1866. That wanted to say to teach the word with the deaf-mute one.
In 1872, it opened its own school in Boston to train teachers the deaf-mute ones. It published a Pionnier lampoon of the visible word and continued to study and inform. In 1873, he became professor of vocal physiology at the university of Boston.
Not being skilful with its hands, Bell was lucky to discover Thomas Watson, a young repairing mechanic and a manufacturer of models, who assisted it, in manner fills with enthusiasm, to imagine an apparatus for the transmission of the sound by electricity. Their long sessions of night started to produce results. The fathers of George Sanders and Mabel Hubbard, two deaf-mute that Bell helped, were impressed of the young teacher. They financially helped it in its scientific continuation. Nevertheless, during the normal hours of work, Beautiful and Watson were obliged to satisfy a schedule of professional requests. It was hardly surprising to see but the health of Beautiful precarious summer. 6 April 1875, one granted the patent for his multiple telegraph to him; but after another six exténuant month of long night sessions in its workshop, while maintaining its schedule of day, Bell were to go back to Canada to the house of his ⁄ her parents to recover. In September 1875, it started to write the specifications for the telephone. 7 March 1876, the patent-office of the United States granted the patent covering number 174,465 to him "the method, and the apparatus, to transmit the voice or other sounds by telegraph by causing undulations electric, similar to the vibrations of the air accompanying the vocal sound or other sounds".
Less than one year following the commercial application, the first hundreds of legal continuations started. Ironically, the telephone - until now was often perceived like a joke and its creator like a prophet or at best as an eccentric - was the subject of the most complicated litigation in the history. The two most famous causes were the cases of Dowd and Drawbaugh, where the beginner company Bell Telephone succeeded in defying the two subsidiary companies of the giant Western Union Telegraph for infringement of patent.
In 1877, Beautiful Maria Mabel Hubbard, 10 years younger than him.
The history of Beautiful does not finish with the invention of the telephone. It was a beginning. As a resident of Washington D.C., Bell continued its experiments in communication, which ended in the invention of the photophone - which transmits the word using ray of light; in the medical research and the techniques to teach the word with the deaf-mute ones.
In 1880, France decrees in Bell the Volta price of a value of 50.000 francs (10,000 $ American) financed by the Laboratory from Volta, in Washington, where in partnership with Charles Sumner and his cousin, Chichester A. Bell, Bell Graphophone invented. Diamond was used to engrave, the wax cylinder to record and speeds were controllable. This apparatus presented a practical approach to record the sound. Beautiful shared the royalties financed by the office of Volta and American Association to promote the teaching of the word to the deaf-mute ones. 8 May 1893, was one day memorable for Bell, because its 13 year old wonder, Helen Keller, took part in the opening ceremonies of the new building of the offices of Volta.
In 1885, Bell acquires a ground on the island of the Cape Breton in Nova Scotia. Surrounded by memories of childhood of Scotland, it built a house of summer, Beinn Bhreagh, supplemented research laboratories.
From 1898 to 1904, Bell succeeded his ⁄ her brother-in-law as a president of the National Geographic Society. Convinced that the geography could be taught by the images, he sought to promote a comprehension of the remote life, whereas the voyage was still limited to some privileged. Again it found a good associated in, Gilbert Grosvenor, his future son-in-law, who transformed a modest lampoon into a single educational newspaper reaching million people in the world.
Interested in aeronautics, it made experiments with giant kites which could transport people. It found a group of four young graduates, of which the inventor and American aviator Glenn Hammond Curtiss, to help it to carry out its theories. Under the blow of an inspiration, Mabel Hubbard Beautiful, wanting to maintain the influence stimulative of the group, founded Aerial Experiment Association, the first research organisation established by a woman. Deafness was not a handicap for the woman of professor Bell. With its group of friends, Bell developed also the aileron, a mobile section of the wing of aircraft which controls rolling. Together they also developed a landing gear with three wheels, which allows initially takeoff then the landing on a ground of vol. By applying aeronautical principles to the maritime propulsion, its group started to work on the hydrofoils, which move above water at high speed. Its "hydrodrome" life size, built in 1917, reached then exceeded 113 km ⁄ h, and during many years, it will be the fastest boat of the world. In Beinn Bhreagh, Bell made enter of new subjects of investigations, such detection with the sonar and solar distillation.
Beautiful continued its studies on the causes and the heredity of deafness. They led it to undertake experiments on the selection, in particular in the breeding of the sheep, and to publish one entitled book : Lifespan and conditions associated with longevity (1918). He died in Baddeck, where a museum containing many its original inventions is maintained by the Canadian government.

Jean Perrin



Born in Lausanne on 17 September 1920, Jean Perrin, wire of Marius Perrin and Julia Perrin-Rathgeb, it belongs to a former family of Vaud originating in Vuiteboeuf-Peney in the district of Sphere. his ⁄ her mother, impassioned by the music, initiates it with the piano. At the 8 years age he works the piano with Marie-Dye stick Moser-Gilliard, girl of Edmond Gilliard. Then it enters, in 1936, with the Academy of Lausanne and continues the study of the piano with Genevieve Andre-Short, woman partuculièrement cultivated, who leads it to the diploma of normal in 1940. It obtains then its diploma of virtuosity in 1942 in the class of Charles Lassueur, a former student of Isidore Philipp. To the Academy of Lausanne, it followed the theoretical branches with Alexandrer Denéréaz while to Geneva, it studied the orchestration with Andre-François Marescotti. In Lucerne, Jean Perrin still works with Edwin Fischer and during the years 1943 to 1945, it is registered in the class of piano of Franz Jospeh Hirt to the Academy of Bern. In 1945, he is prize winner of piano of the Contest of Geneva.
Parallel to its musical studies, Jean Perrin between with the Faculty of Arts of the University of Lausanne where it obtains his licence into 9144. The teaching of French literature of professor André Bonnard had particularly held his attention.
Jean Perrin leaves then for Paris. Its successive stays in the form of six-month periods, in 1947 and 1948 enable him to work the piano with Yves Nat and the composition with Darius Milhaud and Nadia Boulanger. It is also a time when the work of Stavinski, which he liked as of his childhood, renews its interest by its lyricism and its harmonic invoice in particular. Of return in Switzerland, it is dedicated to teaching and continues its work of assistant in the class of Mrs André.
In this same Academy of Lausanne, it is named professor in 1949. In Were worth, it sees itself entrusting, since 1949 also, the higher class of the Academy of Sion.
Simultaneously with his teaching, Jean Perrin makes musical criticism. Aloys Fornerod, chief of the musical heading of the Platform of Lausanne, had proposed criticisms to be written to him. Following the example Fornerod, type-setter like him, Perrin will rather stress readily of his criticisms on works than on the interpreters. He will also sign criticisms in the Gazette of Lausanne.
Pierre Hugli, one of those which followed and makes known the musical route of Jean Perrin could write : "Among the musicians of the French-speaking Switzerland, Jean Perrin is certainly one of those which looked further into the resources of its personality with the greatest requirement as for the sincerity of the expression and the property of the inspiration". One can add that he obeys the same requirement when he makes criticism or writes his presentations of works in the programs of the Chamber orchestra of Lausanne which he signs since 1962. We point out still here that Jean Perrin was the first president of the section lausannoise of the international Company of modern music.
Various aspects of the work of Jean Perrin which can be evoked, it is obviously that of the composition which gives place to the catalogue written today. It counts 50 opus that the type-setter wished to retain. But, let us not mislead there we - it let us suppose - "an other" work, sometimes thrown in draughts, left side to date, destroyed or lost, belonged to its interior course. The type-setter Jean Balissat, confidant and friend of the first hour, are since 1949, recall : "Jean Perrin is not expansive, his capacity of maturation, rather slow, voluntary and regular, is guided by a fidelity inébranlable in an ideal and an inflexible need for absolute". It is to say that all the works quoted and described in this catalogue are it in agreement with the type-setter; the versions, for some, specify the stages of the maturation of which it is question. We also respected the titles, titles of form and subtitles allotted by the type-setter where fidelity with certain forms appears.
This fidelity, this search continues at the same time, Jean Perrin had to only find it. It one of the rare type-setters in French-speaking Switzerland nonresulting or is supported by the tradition choral society although its catalogue contains some partitions with chorus. "To write, paint, compose, are the forms to be, of living which are connected in any form of existence" notes Jean Perrin. The metaphysical reflexion started from its work.
Each partition will have to thus be approached, by taking account of "this duality which fluctuates constantly between an anxious hesitation and the more serene assertion". Moreover, it specifies it itself : "When music is made or that one composes, one decreases his concern". As several criticisms were rained to underline it, at Jean Perrin, the composition answers D an undeniable interior need. It does not have a day entrusted to Jean Balissat : "It is advisable to hold with its interior truth not to rather strongly become a puppet sensitive to all the whims of fashions, if not one writes by trade, or idleness.

Claude Pouillet



Entered at the Teacher training school in 1811, it is there then repeater of 1813 to 1815, then university lecturer of 1815 to 1827. Professor with the college of Thunder since 1809 he is substitute with the Bourbon college for 1817 to 1819 then titular for the pulpit for physics until 1829. He becomes professor of physics of the children of Louis-Philippe in 1827.
He becomes substitute for Biot and Gay-Lussac to the Faculty of Science of Paris (1816), then assistant professor (1827) and finally full professor of the pulpit of physics (1833). He was compensated there by Babinet. Following the blow state of Louis-Napoleon Bonaparte he refuses to lend oath and leaves the pulpit of the Faculty of Science.
He briefly succeeds Pierre Louis Dulong with the pulpit of physics of the Polytechnic school of 1830 to 1831, resigning for health reason.
In 1829 he becomes full professor of the new pulpit of physics applied to arts with the Academy royal of arts and trades. He is appointed by it vice-president then administrator by ordinance of 9 November 1831. In 1849 it is revoked following the invasion of the Academy at the time of the insurrection of 13 June.
Elected official member of the Academy of Science in 1837, it becomes the same year appointed (orleanist) of the Jura (district of Poligny), seat which it preserves until 1848. He was also to advise ordinary with the royal Council of the University and member of the consulting of the Company of encouragement for industry (Committee of economic arts).
Between 1837 and 1838, it carries out thanks to the invention of the pyrheliometer the first quantitative measurements of the heat emitted by the sun. The value which it obtains for the solar constant is of 1228 W/m ², value rather close to the current estimate, which is of 1367 W/m ². According to the law of Dulong and Petit, it estimates the temperature of the sun around 1800°C. This value was revalued with 5430 °C in 1879 per Joseph Stefan.
Its principal work concerns on the compressibility of gases and especially the experimental laws relating to the intensity of the electric current in a closed circuit. In 1825, he invents the tangent galvanometer to be able to measure strong currents. He also knew to specify the concept of electrical resistance and to show that the generators are composed of a pure electromotive force and of an interior resistance. One owes him the law of Pouillet, deduced in an experimental way.

Georg Ohm



Georg Simon Ohm was born in Erlangen, Bavaria, of Johann Wolfgang Ohm, metal worker, and of Maria Elizabeth Beck, the girl of a tailor of Erlangen. Although his ⁄ her parents are not graduate the father of Ohm was a respected man and an autodidact who gave itself to his son an excellent education.
Some of the brothers and sisters of Ohm die in low age and only three survive : he, his ⁄ her younger Martin brother who will become a famous mathematician and his sister Elizabeth Barbara. his ⁄ her mother dies when it is ten years old. Georg was also an excellent stockbreeder of cats, which got its argent de poche to him.
Since their younger childhood Georg and Martin receive from their father of the lesson of very good levels in physics, mathematics, chemistry and philosophy. Georg Simon attends the college of Erlangen from eleven to fifteen years and it receives a very restricted scientific education there, contrasting with the lesson of his father. This characteristic resembles that of the family of Bernoulli, as will notice it Karl Christian von Langsdorf, one of his professors at the University of Erlangen.
In 1805, at the fifteen years age, Ohm between at the University of Erlangen where Karl Christian von Langsdorf, in particular, teaches mathematics to him. Instead of concentrating on these studies it spends its time to dance, make iceskate and playing billiards. his ⁄ her father, in anger in front of the waste of his possibilities, sends it in Switzerland where, in 1806, it takes a post of professor of mathematics in a school of Gottstadt EIB Nydau.
Karl Christian von Langsdorf leaves the University of Erlangen to the beginning of the year 1809 to take a station at the University Ruprecht-Karls Heidelberg and Ohm wants to accompany there to start again its mathematical studies. Langsdorf, however, advises in Ohm to continue its studies of mathematics by itself and reading work of Euler, Laplace and Lacroix. Rather reticent, Ohm takes the advice but leaves its post of teacher with Gottstadt EIB Nydau in March 1809 to become tutor in Neuchâtel during two years. It also continues to take the advice of Langsdrorf by continuing its studies of mathematics. Then, in April 1811 it turns over to the University of Erlangen.
Its studies were useful for him to obtain its doctorate of the University of Erlangen on 25 October 1811 and to immediately join the teaching team as lecturer (lecturer) in mathematics. After three six-month periods Ohm gives up its university station because of not very encouraging prospect, while at the same time it has evil to join the two ends. The Bavarian government then offers to him a post of professor of mathematics and physics in a school of poor quality in Bamberg; post that it accepts in January 1813. Unhappy in its work, it is devoted to the drafting of an elementary book of geometry in order to prove its true capacities. The school is closed in February 1816 and the government sends it in an over-populated school of Bamberg to help with the teaching of mathematics.
It sends its manuscript, once completed, in the Frederic-Guillaume III of Prussia which, satisfied with its work offers a station with the college to him Jesuit of Cologne on 11 September 1817. Thanks to the reputation of this school in the teaching of sciences, Ohm is found to teach as well mathematics as physics. The physics laboratory being well equipped, it is devoted to experiments; wire of metal worker it has a practical knowledge of the mechanical apparatuses.
It enters to polytechnic school of Nuremberg in 1833 and in 1852 becomes professor of experimental physics at the university of Munich, where it dies a little later.
What is currently known under the name of law of Ohm appeared in the book Die galvanische Kette, mathematisch bearbeitet (the galvanic circuit studied mathematically) (1827) in which it provides a complete theory of electricity. The book starts with the mathematical bases necessary to the comprehension of the remainder of work. Ohm presents its theory like resting on actions of contact, in opposition to the concept of remote action. He thought that the propagation of electricity was carried out between "contiguous particles" which is the term that he employed itself ]1_. The book rests on this idea, and in particular on the illustration of the differences in approaches scientific compared to work of Fourier and Navier ]2_.
Its writings are numerous. Most known is its booklet published in Berlin in 1827, under the title Die galvanische Kette mathematisch bearbeitet (in French : The galvanic circuit studied mathematically). This work, whose premises appeared during the two previous years in the newspapers of Schweigger and Poggendorff, exerted an important influence in the development of the theory on the electric current. The name of Ohm was introduced into the terminology of electric science by the means of the law of Ohm (which it was first has to publish in Die galvanische Kette), and was also given to the unit derived from the international system for resistance, the ohm (symbol O).
Although this work strongly influenced the theories later they were initially coldly accomodated. However its work was finally recognised by Royal Society which decrees the Copley medal to him in 1841 ]3_. He becomes foreign member of Royal Society in 1842, and 1845 member of the academy of Bavaria.

Enrico Fermi



Enrico Fermi (1901-1954), born in Rome, Fermi makes its studies at the university of Pisa, then in the principal centers of theoretical physics of Europe. In 1926, he becomes professor at the university of Rome. As from 1932, it concentrates its search on the nuclear physics. It then develops the quantum statistical theory, called today statistical theory of Fermi-Dirac, which explains the behaviour of the electrons and any particle (currently called fermion) obeying the opt-out principle of Pauli.
Fermi works out at the same time the theory of the beta decay, which will appear fundamental in nuclear theoretical physics. This theory stipulates that the emission of electrons during the disintegration of a radioactive core is due to the quantum change of state and not to the presence of electrons in the core. In fact, the atomic nucleus does not contain electrons.
As from 1934, he studies the artificial radioactivity caused by the bombardment of chemical elements by means of neutrons. He thus succeeds in producing new radioelements.
In 1939, Fermi emigrates in the United States with its family and becomes professor of physics at the university of Columbia. It is then fully conscious of the importance of its experimental work within the framework of the production of atomic energy. In December 1942, it realises, at the university of Chicago, the initial chain reaction of controlled nuclear fission. Its work leads to the development of the nuclear reactor. Until the end of the Second world war, he works in Los Alamos (New Mexico) with the Manhattan project of development of the atomic bomb.
In 1946, Fermi takes the direction of the new Institute of the nuclear studies of the university of Chicago. In its honour, the Enrico-Fermi reward is decreed each year with the person having best contributed to the development, the use and the control of atomic energy.

Louis Broglie



Louis de Broglie was born on 15 August 1892 in Dieppe. Descendent of an old Italian family anoblie which counted already several characters marking of the histoire de France, it is an average pupil in mathematics and chemistry. On the other hand, he excels particularly in history, French, philosophy and physics. It is after having simultaneously passed its baccalaureats of mathematics and philosophy, that it obtained at nineteen years, a licence of history, then a licence of right.
One could thus think with difficulty that its name would be associated with the one of discovered most important of the XX ième century physique at the base of all electronics and modern technology. In fact, it is under the influence of his ⁄ her brother elder, then the Duke of Broglie and large specialist in the experiments in physics of the X-rays, which it takes young knowledge of the quantum theory and the problems that it raises.
In 1919, close his demobilization, Louis de Broglie joined his brother who financed his own laboratory where continue search on the X-rays. It specialises in theoretical physics and passes his doctorate in 1924 with Paul Langevin and Jean Perrin in the Ph.D. examining board. It introduced there the revolutionary idea of the undulatory character of the matter, an assumption suggested by work of Einstein in quantum theory about the light.
Einstein immediately includes/understands the validity of the ideas of Louis de Broglie and in fact a broad publicity. Intrigué Schrödinger prolongs the assumptions and the relations mathematics suggested by Louis de Broglie and discovers the fundamental equation of the wave mechanics bearing its name today and generalised by Von Neumann and especially Paul Dirac.
Davisson and Germer were not long in giving a direct experimental confirmation of mature undulatory of the matter and Louis de Broglie will see himself allotting the Nobel Prize of Physics in 1929.

Blaise Pascal



Blaise Pascal was born on 19 June 1623 in Clermont. He is the 3rd child and single son of Etienne Pascal, who is President of the Court of the Assistances, and thus belongs to the noblesse de robe (one finds then in this medium, like in the ecclesiastical mediums, among the most cultivated people). As for her mother, Antoinette Begon, it dies 3 years after her birth. In 1631, the family settles in Paris.
It is Etienne Pascal who deals with the education of his son, far from the banks of the college or the university. He has not very orthodoxe visions, and he prohibits with his son the training mathematics before 15 years. But the legend tells that Blaise, piqué by curiosity, was surprised by his father only showing, at 12 years, that the sum of the angles of a triangle made 180°. Following that, it was authorised (and encouraged) to read the Elements of Euclide.
As of 14 years, Blaise Pascal accompanies his father with the meetings by the Academy of tiny Marin Mersenne, where various scientists discuss of all kinds of questions. At 16 years, it made there its first exposed, where it shows several theorems of projective geometry, whose famous property of the mystical hexagon registers in conical. One year later, it publishes Essai for the conical ones.
In 1639, Etienne Pascal is promoted by Richelieu police chief with the lifting of the taxes near the Intendant of Normandy, and the family settles in Rouen. The task of collection of the taxes is difficult and repetitive, and to relieve work of his ⁄ her father, Blaise Pascal with the idea of a machine to automate calculations : it is the first desk-top calculator history, clarification in 1642.
The year 1646 marks a first turning in the life of Pascal : his ⁄ her father was wounded with the thigh, and it is looked after by two doctors, the Deschamps brothers, who make read with the family of the works of inspiration Jansenist, and convert it with a more enthusiastic Christian life. It is the "first conversion" of Pascal.
In 1647, health issues force Pascal to go back to Paris. On a scientific level, Pascal is interested in the quarrel of the existence of the vacuum, which opposes Torricelli to Descartes. He proposes several experiments to validate the existence of the vacuum, and in particular makes carry out by his brother-in-law a famous experiment at the top of the Puy-de-Dôme which establishes in an irrefutable way the part played by the pressure of the air.
24 September 1651, the father of Pascal dies and this affects it much. Contrary to his Jacqueline sister, who enters to the monastery of Port-Royal, Pascal finds refuge in the fashionable life and sciences. It is interested then in the numbers, has epistolary exchanges with Fermat which found the probability theory (one owes in particular in Pascal the invention of the concept of hope), studies in 1654 the arithmetic triangle and thus invents the reasoning by recurrence.
The night of 23 November 1654, Pascal knows one night of extase mystical, where it meets God and is inhabited by feelings of "certainty, joy, peace, tears of joy". It is the "second conversion" of Pascal, which leads it to give up the worldly pleasures, and with the social sciences, vain vis-a-vis divine sciences. He withdraws himself as from 1655 in the Jansenists of Port-Royal, which are opposed to the Jesuits of the Sorbonne then. Pascal takes share with the quarrel, defending his friends Jansenists by the writing of 18 letters called the "Provincial ones" (of the title of 1st, Written letters to provincial by one of his ⁄ her friends).
Pascal renews contact after 1658 with the scientific life by studying the properties of the cycloid one. He also starts to write an apology for the Christian religion, which will be published in posthumous title under the name of Pensées. It tombre seriously sick in February 1659, and this slows down the realisation of its projects. Its last invention is the creation of the carosses on the 5 ground, first joint transport system in Paris. He dies on 19 August 1662, undoubtedly of the continuations of a cancer of the stomach.
A young death (39 years), a multitude of passions and a fragile health undoubtedly prevented Pascal from having a broader mathematical production. It is necessary to finish by underlining art to write at this man, as well in his scientific writings as philosophical.

Jean Le Rond D’alembert



Jean Le Rond D’alembert, born on 16 November 1717 in Paris, is the illegitimate child of an artillery police chief and a marchioness. Given up with its birth on the steps of the Parisian church of Jean Saint the Round (which gave him its first name), it is collected by the woman of a craftsman-glazier who will raise it like his son. In return, of Alembert will live with it until the death of this one (either during 48 years!). Secretly, his ⁄ her father will pour a pension to him which will provide for the education of the young man. Alembert appears particularly gifted for mathematics, and he successfully studies the right and medicine.
After first reports on mechanics of the fluids and the calcul intégral, it is allowed at 24 years with the Academy of Science like associated assistant astronomer. In 1743, it publishes its important Traité of the Dynamics, where it improves the definition of a force, and what is called gives from now on the principle of Alembert (=conservation of the momentum). In 1747, he writes an article on the vibrating cords, where, for the first time, he gives and solves the partial derivative equation which governs the propagation of the sound waves. One also must in Alembert of the Reflexions on the general cause of the winds (begun again and generalised by Euler), and a treaty on the precession of the equinoxes, where it gives a solution partial to the problem of the 3 bodies. This work of Alembert mathematically seems very solid, but calls sometimes upon simplifications of very debatable physical problems, even opposed to reality. That will be worth to him sharp quarrels with Euler, Clairaut, and D. Bernoulli.
As from 1746, of Alembert launches out with Diderot in a monumental adventure, the drafting of the Encyclopaedia, reasoned Dictionnaire of Sciences, whose 1st volume appears in 1751. In the preliminary Speech which opens the Encyclopaedia, of Alembert the link between the advance in knowledge and the social progress affirms. It fits completely in the current of the Lights, and it fights against the religious and political obscurantism. It is this philosophical activity which replaces little by little its work of mathematician.
Alembert almost never left Paris. He refuses in particular in Frederick II the presidency of the Academy of Berlin; he declines also the invitation of Catherine II to become the tutor of his son (in Russia), in spite of the important purse that she proposes. On the contrary, he attends the shows and likes the fashionable, Parisian life. In 1754, he becomes member of the Académie Française, of which he is the perpetual secretary as from 1772. Its domination is then almost despotic there, and he is liked little by his pars.
The end of the lifetime of Alembert is marked by the disease, and he dies on 29 October 1783 of the continuations of these diseases. Let us leave the conclusion to his ⁄ her adoptive mother, not very satisfied with the activities of his ⁄ her son : "What a philosopher? It is insane which torments all its life so that one speaks about him when he is not there any more".

Isaac Newton



One knows life of Newton in general the episode legendary apple which would have suggested the theory of the gravitation to him. But one often forgets that this brilliant physicist was also a brilliant mathematician, at the time where the borders between sciences were marked little.
Isaac Newton was born in Woolsthorpe ]England_ on 25 December 1642, year of died of Galileo. his ⁄ her parents are farmers, but his ⁄ her father dies two months before his birth. his ⁄ her mother remarie, and it seems that the childhood of Newton, sent in his ⁄ her grandmother, is not very happy. At the public school of Grantham, Newton is a not very attentive pupil. Around 16 years, he is recalled by his mother to deal with the family field, but this work is appropriate to him hardly, and he turns over to the school to prepare his input at the University. Stokes is the first to detect at Newton a promising talent, and it helps it to enter in Trinity College of Cambridge in 1661. Over there, apart from the courses of Cartesian philosophy, Newton is interested personally in astronomy, and thus with mathematics because it misses many geometrical concepts to him to include work of Halley.
At the summer 1665, the plague falls down on England, and Newton must turn over in its native area. It is for this two years period that one locates his first spectacular projections in mathematics, physics, and more particularly in optics : Newton understands that the white light is not an entity, but is the sum of coloured lights. On its return to Cambridge, its engineering is detected by Barrow, which makes known its work, the assistance to make a success of its last university examinations, and in 1669 the pupil succeeds the Master with the pulpit of mathematics. In 1672, it enters in Royal Society of London following the manufacture of a spherical reflecting telescope dépouvu of chromatic aberration.
The major work of Newton is Philosophiae naturalis principia mathematica published in 1687, which marks the node of the Newtonian thought. Principia mark the beginnings of the mathematisation of physics. They comprise all the principal bases of traditional mechanics : equality of the action and the reaction, principle of inertia, and especially law of universal gravitation : two bodies attract each other with a force proportional to the product of their mass and inversely proportional to the square of their distance. In mathematics, in addition to the classification of conical and the formula of the binomial for nonwhole exhibitors, Newton is regarded as the Co-inventor of the infinitesimal calculus, called by him method of the fluxions. This infinitesimal calculus is considered through kinematics, whereas at Leibniz it proceeds of the geometry. Derivation is still considered in an intuitive way, but the stakes of the modern analysis are posed.
Newton was undoubtedly a complex and tormented personality. It feels reluctant to communicate to the other scientists its discoveries, which will be worth to him some violent quarrels of priority with Hooke (for the universal gravitation) and Leibniz (about the infinitesimal calculus). It devotes much time to alchemy, with theology. In 1693, Newton suffers from an serious attack from nervous breakdown, which makes him give up any new search, to the profit from a synthesis and improvements from its former results. It also occupies of the prestigious administrative offices : it is named director of the Currency, and in 1703, it is elected President of Royal Society. Annobli in 1705, it dies on 19 March 1727 in London, and it is buried with the abbey of Westminster, at the sides of kings Angleterre.

James Watt



It was born on 19 January 1736 in Greenock and it died on 19 August 1819 with Heatfield. James Watt went to school in an irregular way because his ⁄ her mother was very informed and courses gave him. At the 19 years age, it leaves to London to work as apprentice in a manufacturer of instruments where it learns the principles from mechanics. But because of its troubles of health it returns to Glasgow where it is engaged by the university to maintain the instruments physics. In 1763, a professor of the university gives him to repair a steam engine of Newcomen who functioned badly and, it realised that this one wasted too much energy. He thus decides to improve it for an industrial use. In 1765 he adds a condensing chamber separated to increase the effectiveness of the machine.
Then it improves the insulation of the cylinder and adds a metre, an indicator to measure the steam pressure in the cylinder and a control valve of power. In the years 1780, it sets up the system doubles actions (1782). He adds a wheel and adapts the centrifugal governor to control the speed of the machine (1788). He invented and patented the gears sun-planet which consist in converting a vertical movement into rotation movement (1781). It is in 1784 it makes patent the steam engine. The improvements of the steam engine made by James Watt were a key stage of the industrial revolution. Its name was given to the unit power.

Niels Bohr



Niels Bohr was born in 1885 in Copenhagen, capital of Denmark. One finds there the largest port of the country, it is also the centre of the intellectual, industrial policy and the city of the most prosperous Denmark in the years 1920.
Niels studied at the University of Copenhagen and to have shortly after finished its studies, it left to work in Cambridge, in England. From there, it worked out the theory of the atom and its atomic model with its levels energitic which it will finish in 1913. Seven years later, it returns to Copenhagen.
He became director of the (ITP) in Copenhagen in the same year, that is to say in 1920. He will be the director until the Second world war. In 1922, it receives the Nobel Prize for the model of the atomic structure. A little later the institution, of which he was director, took its name in its homage.
In 1922, his ⁄ her son, Aage Niels, proposed a nuclear model which was worth the Nobel Prize in 1975 to him. In 1933, Niels Bohr proposed a theory of the nuclear fusion, based on the analogy between the core and the droplet. During the Second world war, it took refuge in England and Sweden until the Americans ask his assistance for the construction of the atomic bomb. He discovered, thanks to experiments, that one could separate an atomic nucleus into two. After the war, it returned to Copenhagen where it died in 1962 at the 87 years age. Niels Bohr worked with several chemists known in its various discoveries.
According to the laws of the traditional physics of Rutherford, an electron which turns around its core should release from the light or other kinds of energies. But there is a problem : if the electron did that, it would lead while turning in spiral to the core and would involve the destruction of the atom. This law is false, because separately the radioactive elements, the atoms are stable. This is why the model of Rutherford required that it be worked.
A second physicist enters in account : Max Planck (1858-1947). It invites the researchers to consider the following question : why an increasingly hot body pass does to the dark red, with the clear red then with the white? Planck has its theory. It suggests that a hot body emits quanta of energy. In other words, a hot body emits packages of energy in fontion of the amount of power which it had accumulated.
Thanks to work of Rutherford and Planck, a third physicist, Niels Bohr enter the history of the atomic model. Bohr takes the theory of the electron turning around the core of Rutherford and the quantum theory of energy of Planck. He works out a model of the structure of the atom by proposing that an atom has energy levels on which the electrons turn around the core. These levels all are distinct from ⁄ to each other, one counts of them seven and the number of electron varies according to the level. Such as for example, the first level can contain two electrons, the second can have of them eight, etc an electron located on the first circular level of the hydrogen atom in its natural environment has a magnetic unit of moment, that is to say the equation : UB = eh ⁄ 2m. What wants to say that we can calculate the energy of the electron with this equation. These energy levels all are stable. It is possible to calculate the released energy of these levels as well as the number of quanta corresponding to the action of the electrons. On these trajectories, the electrons do not radiate. Niels Bohr worked out a theory allowing the spectroscopic interpretation of the hydrogen atom. He affirms that an electron which receives energy of outside (e.g. : heat) becomes excited and passes on a higher level. The more the electron receives energy, the more it goes up. The electron which was propelled on another level wants to return on its initial level. To return, it releases all the energy which it had accumulated in the form of light. The intensity of light varies according to the released amount of power. The colours can pass from the infra-red to the ultra-violet. Its theory supposes that the electron cannot be between two levels.
Niels also worked on nuclear fission. It based a theory on which uranium 238 underwent fission only when it was bombarded by neutrons of energy higher than an méga-electronvolt. The slow neutrons started only the fission of the rare isotope 235U which is present in natural uranium for part of 137. From this experiment, it came out that, to carry out a bomb with uranium, one was to separate the isotopes from uranium.
In short, Niels worked in order to arrive very a long time at its ends. It had to make much experiments to lead to its atomic model. Finally, it has merit for its great discoveries, but it should be said that it was based on several theories of its fellow-members like Rutherford, Planck, Joliot, Szilard, Wigner, Weisskopf and Fermi in order to obtain a database which gave him a skilled of inch.
Several large physicists brought to us, during the years, of many important discoveries the purpose of which are to upset the course of the history. They delivered a still useful knowledge to us today. It is what enabled us to create various work tools. Such is the case of the physicist called Niels Bohr.
He is one of the founders of quantitative mechanics. He applied the quantum theory to the planetary representation of the atom of Rutherford and from that, he proposed an atomic model which bears its name today. The purpose of what was to help the chemist Glenn T. Seaborg to classify the periodic table in periods and it is what improved the table such as one knows it today.
Niels also contributed to the invention of the theory of the nuclear fission based on the analogy between the core and a droplet while making use of its theory. It could discover by its observations which one could separate an atom into two. Following this discovery, Bohr and his associates could create the atomic bomb : this famous atomic bomb which was released on Hiroshima during the Second world war. It is one of most attractive discovered, but it is also most terrible of the 20th century, which was not exceeded yet nowadays. The bursting of these bombs cause several natural disasters, like the disappearance of animal species and vegetable. It gives death!
This discovery contributed to the development of the nuclear plants which are useful for the electrical production. Niels Bohr informed us of its discoveries, which allowed the advance of science.

Mikhaïl Dolivo-Dobrovolski



Michail Dolivo-Dobrovolski, is born on 21 December 1861 close to Saint-Pétersbourg.
From 1872 to 1878 he lives with his parents with Odessa. In 1878 it integrates the technical training school of Riga (Latvia). It seems that he belonged to student movements of opposition to the mode tsarist. In 1881 after the assassination of the Tsar Alexandre II it is expelled of its school and is condemned to the exile.
With his parents it settles in Darmstadt and continues its studies at the polytechnic school from where it leaves graduate in 1884. He works then as assistant of professor Erasmus Kittler. In 1887 he resigns and goes to Odessa where he marries Cornelia Tumba (Greek nationality). Of return in Germany it is recruited by Deutsche Edison Gesellschaft in Berlin which, the same year becomes the AEG.
Between 1888 and 1891 it develops its principal invention : the generator of three-phase current. 23 May 1891 is born his ⁄ her Dimitri son. During all its career it will deposit an about sixty patents. In 1900 Russia which recognised its engineering to him proposes him the direction of the Polytechnic Institute of Saint-Pétersbourg. But the affaire is not done and, although it preserved its Russian nationality, as from 1903 it ceases practically any contact with its country of origin.From 1903 to 1909 it resides in Switzerland (being sick core since childhood, perhaps this for medical reason was). While preserving its Russian nationality, it obtains Swiss nationality in 1905.
In 1907 he marries in second weddings Jadwiga Polaczkówna.
In 1908 it is named plant manager of Berlin of the AEG.
In 1909 it is devoted to its search at the Technical University of Darmstadt and in parallel is named Chief technical officer of the AEG.
He dies on 15 November 1919 with the university private clinic of Heidelberg of the continuations of his cardiac problems and is buried with the cemetery of Darmstadt with his second wife.
He was the first cousin of the General-baron von Bilderling.

Nikola Tesla



Nikola Cyrillic Serb Tesla, born on 10 July 1856 in Smiljan, Worsens of Austria, today in Croatia, and dead on 7 January 1943 in New York, the United States, is an inventor and American engineer of Serb origin, who mainly worked in the field of electricity.
He is often regarded as one of the largest scientists in the history of technology, to have deposited more than seven hundred patents (which for of them will be allotted much to Thomas Edison) describing new methods to carry out the energy transformation. Tesla is recognised like one of the most creative engineers of the end of the XIX e century and the beginning of the XX e century. For its part, he rather preferred to be defined as a discoverer.
Its most known work and most largely diffused concerns electrical energy. He developed the first alternators allowing the birth of the electrical communications of distribution in AC current, of which he is one of the pioneers. Tesla was interested much in modern technologies focusing itself on the electricity which was the core of its inventions. It is known to have known into practise to put the discovery of the undulatory character of electromagnetism (theorised by James Clerk Maxwell in 1864), by using the Eigen frequencies of the circuit components in order to maximise their output.
As of its childhood, following various emotional events in particular the death of his ⁄ her groin brother Daniel, it develops great intellectual capacities of which it testifies in his autobiography profiting from a photographic memory out of the commun run, of an inventive engineering, as well as a gift of visualisation returning useless models and diagrams to him. At 17 years, it starts to invent like an autodidact.
In 1875, it enters to the polytechnic school of Graz, to Austria, or it studies mathematics, physics and mechanics. A purse is allotted to him by the administration of the military Confines, putting it at the shelter money problems. This does not prevent it however from working with eagerness to assimilate the first two years program of studies in one year. The following year, the removal of the military Confines withdraws any financial aid in Tesla, except that, very thin, which his ⁄ her father can bring to him, which does not enable him to complete its second year of studies.
After a few last years to seek work, Nikola Tesla begins as an engineer in 1881, in Budapest, with the central Office of the telegraph of the Hungarian government.
It is also interested in Hindu mythology, then with the Sanskrit like Oppenheimer.
1882, it comes to Paris and works for the company Continental Edison with the improvement of the equipment coming from the parent company. According to its autobiography, it completes to develop the first engine with induction using the AC current. It develops several instruments which use the rotation of magnetic fields, and obtains a patent in 1888. Nobody in Europe being interested in his technology, it then agrees the offer of Thomas Edison to come to work in the United States.
In 1884, 28 years old, it unloads in the United States, or Edison has just created the electrical communication feeding the town of New York. This network, based on the D.C. current, suffers from serious abnormal operations : frequent accidents, regular breakdowns, several fires start Moreover, this electricity cannot be conveyed for a long distance, it requires a power station all the two miles.
Tesla is in favour of the adoption of the AC current, which would solve all these problems, while Edison, burning defender of the D.C. current, is completely opposite there. Of this fact and because of the very narcissistic personalities of the two men, a savage opposition divides them, which leads Tesla to resign.
In 1886, George Westinghouse is interested of close with the AC current. As a direct competitor of Edison, he dreams to supply the United States in electricity. He engages Tesla like advising. A titanic fight (called the War of the currents) begins between Westinghouse-Tesla and Edison, it ends up turning to the advantage of the couple Westinghouse-Tesla.
In 1893, Westinghouse announces that its company has just obtained the contract of installation of all the electric infrastructure. Quickly, the United States will exclusively use the AC current recommended per Tesla.
Since 1943, Tesla is regarded as the creator of the radio under the patent deposited in United States Patent and Trademark Office on 20 March 1900. Before Tesla does not obtain the primacy of the invention, this one was allotted, wrongly, in Marconi, more popular and better business man.
One owes him the asynchronous electrical motor, the polyphase alternator, the three-phase star assembly, the rotary convertor.
He is the principal promoter of the transport of electrical energy in AC current.
In 1889 it is interested in the high frequency and produces a generator providing a frequency of 15 Khz.
It exposes in 1891, during demonstrations, its lamp high frequency with carbon pellet, more economic than our current fluorescent tubes and of which the concept precedes that of the accelerator with particles or that of the electron microscope.
From 1896, in parallel of Branly, it carries out experiments of remote control. While being based on the discharger of Hertz, it develops the reel which bears its name and which constitutes a first transmitter granted to deadened waves. Tesla defines the bases of the tele-automatic. It conceives that one can one day order vehicles to hundreds of kilometers without there being of crew, by using wireless-aware telegraphy, It creates two ships remote-controlled robots of which is sinkable 1895 contain actually the specifications of a boat torpedoes without crew provided with six torpedes of 4,20 metres
Experimentation of the gigantic high frequency resonators of 1899 to 1900 in Colorado Springs, for the construction of a tower of telecommunication in Wardenclyffe (Shoreham), Long Island.
Tesla has, moreover, writes its theory on the weapons with energy directed before the beginning of the XX esiècle, its famous Death ray.
Radiocommunications and transmission by waves
It is an air-gap transformer with primary and secondary reels regulated on the resonance which converts with high frequencies of the high currents of relatively weak tensions, while current low of high voltages.
As long as the frequencies are raised, the alternative courses of very high voltages run out largely on the surface of the skin, without causing damage. Milliamperes penetrating in nervous fabrics can kill whereas many amps on the surface of the skin can be tolerated during urgent briefs!
The reel of Tesla is used as a device of production as high voltages, always used nowadays in a form or another in any radio receiver or of television; it will very quickly become part of the equipment of any university research laboratory.
Its reel has several medical applications. In 1890, it is published an article which gives the therapeutic values on the human body of the internal heating by currents of high frequencies. This phenomenon will be known under the term of diathermy.
Tesla discovers the principle of the radar in 1900, it develops it and publishes in spite of financial problems the principles of what will become, almost three decades later, the radar. It functions like the ultrasounds of the bats : a device sends a concentrated radius of a current of tiny electric charges vibrating to a very great frequency, then after reflexion on the target, it takes delivery of the radius which it analyses for finally obtaining an image of the target. Fifteen years after the description of the radar per Tesla, of the research teams American and French in parallel work steadily to develop a system functioning according to its principles. In 1934, a French team develops and installs radars on boats and ground stations by using apparatuses designed according to the principles stated per Tesla. The radar was of a great help to the British during the Second world war to prevent the air raids of the German army.

James Clerk Maxwell



James Clerk Maxwell 13 June 1831 in Edinburgh, in Scotland - 5 November 1879 is a physicist and Scottish mathematician. It is mainly known to have unified in only one whole of equations, the Maxwell equations, electricity, magnetism and induction, by including an important modification of the theorem of Amp. It was at the time the model more unified electromagnetism. It is also famous to have interpreted, in an article in four parts published in Philosophical Magazine entitled One Physical Lines off Force, the light as being an electromagnetic phenomenon while being based on work of Michael Faraday. It in particular showed that the electric fields and magnetic are propagated in space in the form of a wave and with speed of light.
These two discovered allowed important later work in particular in restricted relativity and quantum mechanics.
It also developed the distribution of Maxwell, a statistical method of description of the kinetic theory of gases.
Maxwell is regarded by many physicists as the scientist of the XIX esiècle having had the most influence with the XX esiècle. Its contributions to science are regarded by certain as as important as those of Isaac Newton or Albert Einstein. In 1931, for the centenary of the birth of Maxwell, Einstein itself described work of Maxwell like major and profitable that physics knew since the time of Newton
Maxwell was fascinated by the geometry, redécouvrant the regular polyhedrons before to have received any formal teaching. Nevertheless the essence of its talents remain unknown, and although it gains a price in religious biography in second year, its school work remains pain-killer until, with the thirteen years àge, it gains the medal of mathematics of the school and the first price in English and poetry.
For its first scientific work, with àge the fourteen years, Maxwell writes an article on average mechanics to plot mathematical curves with a piece of string as well as the properties of the ellipses and the curves to more than two hearths. Its work, Oval Curves, are presented to Royal Society off Edinburgh by James Forbes, professor of natural philosophy at the University of Edinburgh, too young Maxwell being judged to do it itself. Work was not entirely original, Descartes having examined the properties of such curves multifocales to the XVII esiècle, even if Maxwell simplified their construction
Maxwell leaves the academy in 1847 with the sixteen years àge and follows courses to the University of Edinburgh Having the possibility of returning to Cambridge after its first quarter, Maxwell decides nevertheless to finish his three quarters of studies in Edinburgh. The main reason is the distance between Cambridge and at his place, which would imply to see his ⁄ her father only twice a year. The other reason is concern for the continuation of its career : he wants to become scientist, but employment in the field being rare at the time and it would have been much more difficult to obtain a station in a university as prestigious as that of Cambridge.
The University of Edinburgh accomodates in its teaching team of the recognised personalities. In first year Maxwell has as professors William Hamilton in logic and metaphysics, Philip Kelland in mathematics and James Forbes in natural philosophy. Maxwell however does not find his courses in Edinburgh particularly demanding also it finds time to plunge himself in his own personal studies during his spare time, particularly at the time of his returns to Glenlair. He can then make experiments with apparatuses of improvised chemistry and electromagnetism, but its main concern relates to the properties of the polarised light. It formats blocks of gelatine, subjects them to various constraints then, using two polarising prisms which William Nicol offered to him, it observes the colours developed in the frost. Maxwell has just discovered photoelasticity, a method of determination of the distribution of the constraints inside a physical structure.
In its eighteenth Maxwell year in two articles for the Transactions the Royal Society off Edinburgh contributes off, of which one of both, One the Equilibrium off Elastic Solids, poses the foundations of important discovered that it will carry out later : temporary birefringence in a viscous liquid by a shear stress. The other article is entitled Rolling Curves. For its first article of schoolboy, Oval Curves, Maxwell is considered too young person to go up to the platform and to present it itself. So it is read in Royal Society by its professor Kelland. Young Maxwell in Trinity College in Cambridge. It holds with the hand one of its wheels with colours. In October 1850, already become an achieved mathematician, Maxwell leaves Scotland for the University of Cambridge. It is initially in Peterhouse, but before the end of the first quarter it re-enters in Trinity College, or it thinks that it is easier to obtain a grant. In Trinity College, he is elected at the known secret society under the name of Cambridge Apostles. In November 1851, Maxwell studies with William Hopkins, whose capacity to support the development of the mathematical talent were worth to him the nickname of maker of senior wrangler. A big part of the translation of these electromagnetic equations is carried out in Trinity College.
In 1854, Maxwell is diplà´mé of Trinity in mathematics. He obtains the second notes highest with the final examination, arriving behind Edward Routh, and thus gaining the title of second wrangler, but is declared ex-aequo with Routh in the most demanding test of the examination of the Smith Price. Immediately after having received his diplà´me, Maxwell reads in Cambridge Philosophical Society a new report, One the Transformation off Surfaces by Bending. It is about one of some purely mathematical articles which he will publish and which shows the growing scale of Maxwell as a mathematician. Maxwell decides to remain with Trinty and request to become fellow a procedure which lasts several years normally.
The nature of the perception of the colours was one of its private interests since the time or it was student of Forbes to Unversité of Edinburgh. Maxwell, by using coloured rotary cutters invented by Forbes, is able to show that the white light results from a red mixture of lights, green and blue. Its article Experiments one Colour, which poses the principles of the combinations of colours, is read in Royal Society of Edinburgh in March 1855. Maxwell is made fellow of Trinity in October 1855, more quickly than the standard and it is asked to him to give courses in optics and hydrostatic like writing texts of examination. In February of the following year, it is informed by Forbes that a pulpit of natural philosophy in Marischal College in Aberdeen is vacant. It hastens to postulate. his ⁄ her father the assistance to prepare his file and his references but dies on 2 April with Glenlair before connaà®tre the results of the candidature. Maxwell accepts the station in Aberdeen and leaves Cambridge in November 1856.
Maxwell is then twenty-five years old and is younger fifteen years than the majority of professors de Marischal, which does not prevent it from engaging in new responsibilities while becoming head of department, establishing a program and preparing the courses. He spends 15 hours per week to give courses including a weekly course to the college of the workers. He lives Aberdeen during the six months of the academic year and spends the summer to Glenlair, in the house which he inherited his father.
He is particularly invested in a enigma which has impassioned the scientists for two hundred years : the nature of the Saturn rings. The reason for which they remained stable without disaggregating, to disperse or be crushed on Saturn was unknown. The problem takes an particular importance then because St John College chooses it like topic of the Adams Price in 1857. It spends two years to study the problem, proving that a solid ring could not be stable and that a fluid ring would be forced by mechanical waves to be divided into bubbles. Without any experimental observation Maxwell concludes that the rings must be formed many small particles which it calls brig-beat, orbiting each one independently around Saturn. It receives the 130 pounds of the Adams price off in 1859 for its test One the Stability Saturn Rings; he is the only candidate to have produced sufficient advanced to be able to be retained. Its work inspires in George Biddell Airy this comment : It is one of the most remarkable applications of mathematics to physics than I ever saw. It is necessary to await the Voyager program in the years 1980 to have an experimental confirmation of this theory. Maxwell also mathematically invalidates the assumption nébulaire (which affirms that the solar system was formed by progressive condensation of a purely gas nebula) by introducing into the theory the taking into account in the model a formed additional part of small solid particles.
In 1857, Maxwell binds friendship with the main thing of Marischal, the Reverend Daniel Dewar and meets the girl of this last, Katherine Mary Dewar. He become engaged in February 1858 and marry in Aberdeen on 2 June of the same year. In 1860, Marischal College amalgamates with its neighbour King College to form the University of Aberdeen. There are no chambers available for two professors of natural philosophy and Maxwell, in spite of his scientific stature, finds himself then congédié. Its candidature for the station of Forbe to Edinburgh fails, but it obtains, in the place, the pulpit of natural philosophy in King College of London. During the summer 1860, after being itself given of a serious access of variola, Maxwell leaves for London with his Katherine wife
Work of Maxwell to King College is perhaps most productive of its career. It is rewarded for the Rumford medal of Royal Society in 1860 for its work on the colour and elected official in Society itself in 1861. This period of its life sees it carrying out the first photography colour, to develop its ideas on the viscosity of gases and to propose a system of definition of the physical quantities called analyses dimensional. Maxwell also often follows the conferences of Royal the Institution, or it is in regular contact with Michael Faraday. The two men are not extremely close because Faraday is 40 years old more than Maxwell and starts to show signs of senility, but their relation is impressed of a reciprocal respect for their competences. This period is primarily known to be that of advanced of Maxwell in electromagnetism. It off examines in 1861 the nature of the electromagnetic fields in its article in two parts One Physical Lines Force, in which it provides a conceptual model of electromagnetic induction consisting of small revolving cells of flow of the magnetic field. Two other parts of the article are published in the beginning of 1862 : in the first he discusses the nature of the electrostatics and the displacement currents. The last milked part of the rotation of plans of polarisation of the light under the effect of a magnetic field, a phenomenon discovered by Faraday and known under the name of Faraday effect
From 1855 to 1872, it publishes a series of search concerning the perception of the colours, for which it receives the Rumford medal in 1860, and daltonism. The instruments which it used for its search were at the same time simple and practical as for example the discs of Maxwell which were used to compare the various mixtures of the three primary colours by observing a coloured rotary cutter.
One of the most important contributions of Maxwell is the kinetic theory of gases. Initiated by Daniel Bernoulli, this theory was then developed successively by John Herapath, John James Waterston, James Joule and especially Rudolf Clausius, until being largely accepted. Nevertheless it accepted a significant development on behalf of Maxwell.
In 1866, he formulates, independently of Ludwig Boltzmann, the kinetic theory of gases known as of Maxwell-Boltzmann. Its formula, called distribution of Maxwell, gives the proportion of the molecules of a gas developing at a certain speed to a given temperature. This approach generalises the laws of thermodynamics and makes it possible statistically to explain a certain number of experimental observations. Work of Maxwell in thermodynamics also leads it to formulate the experiment of thought called the daemon of Maxwell.
Most of the scientific life of Maxwell was devoted to electricity. Its greater contribution is the development and the mathematics formulation of preceding work on the electricity and magnetism carried out by Michael Faraday and Andre-Marie Ampère in particular. It draws from it a unit from twenty differential equations to twenty variables, reduced later to four. These equations, from now on known under the name of Maxwell equations, are presented the first time to Royal Society in 1864 and describe the behaviour and the relations of the electromagnetic field like its interaction with the matter.
The electromagnetic equation of wave of Maxwell envisages the existence of a wave associated with the oscillations with the fields electric and magnetic and moving in the vacuum at an easily accessible speed in experiments. With the means of the time Maxwell obtains a celerity of 310740000 m/s. In its article of 1864, has Dynamical Theory off the Electromagnetic Field Maxwell written :
The agreement of the results seems to show that the light and magnetism are two phenomena of comparable nature and that the light is an electromagnetic interference being propagated in space according to the laws of electromagnetism. This forecast appeared correct and the relation between light and electromagnetism is regarded as one of the greatest discoveries of the XIXe century in the field of physics. At this time Maxwell thinks that the light propagation requires a medium for support of the waves : ether. With time the existence of such a medium, filling all space and apparently undetectable by average mechanics, will pose more and more problems to be put in agreement with the experiments such as that Michelson and Morley. Moreover, that seems to impose an absolute reference frame in which the equations are valid, but also forces those to take a different expression for an observer moving. It is this last difficulty which will lead Albert Einstein to formulate his restricted theory of relativity for which the existence of ether is not necessary any more.

Michael Faraday



Michael faraday is a physicist and a British, known chemist for her fundamental work in the field of electromagnetism and electrochemistry.
Michael Faraday is born on 22 September 1791, in Newington Butts, a village of Surrey (England), integrated today in large London. Its family, poor, belongs to a sect, the glasites, resulting from the Church of Scotland. his ⁄ her father, James Faraday, had been the blacksmith of the village of Outhgill in Westmorland from where he emigrated about 1790. The Michael young person, resulting from a phratry of four children, has only one primary education and car-educated himself for the good portion of acquired knowledge. As of the 14 years age, he is apprentice at George Riebau, a bookseller-bookbinder and fact proof of great manual talents and curiosity : "apprentice, I adored lira the scientific books which fell me under the hand". Among those, let us mention the book of Isaac Watts the improvement of the spirit, of which it will draw the "six principles from Faraday" and the scientific books of popularisation of Jane Marcet, of which Conversations on chemistry.
One day, one of the customers of the bookshop, offers places to him to attend conferences of chemistry carried out by the chemist Humphrey Davy, member of Royal the Institution and Royal Society. Thus old twenty years, Faraday goes for the first time in Royal Society of London to attend the conferences of Davy. Royal Society was one of the high places of British science and Humphrey Davy had stuck to bring the prestige to him which it needed. Faraday very quickly is impressed and fascinated by work which Davy undertakes to which he writes, uniting with its letter its notes taken at the time of the conferences. Sir Humphrey Davy, following an accident of laboratory, damages the sight and fact call, in 1812, with the Faraday young person to be used to him as secretary.
2 June 1821, Michael Faraday Marie with Sarah Barnard (1800-1879), met with the church glasite, but this marriage remained without child.
He is elected in Royal Society in 1824, and is named directing of the laboratory of this institution in 1825. In June 1832, the University of Oxford names it Honorary doctor in civil law. If it accepts this honorary and university title, Faraday will reject its ennoblement under knight and will twice refuse by the honour to become President of Royal Society. In 1833, he is the first holder of the pulpit fullerienne of chemistry (Fullerian professorship) at Royal the Institution, without obligation to teach.
In 1848, on a proposal from the prince-consort, Albert of Saxony-Cobourg-Gotha, Michael Faraday sees itself allotting a house in Hampton Court, free of any constraint. This house, known as being that of the Master-Mason, is later called Faraday House, and is with number 37, in Road Hampton Court. In 1858, Faraday takes its retirement and lives definitively it. It is there that he dies, on 25 August 1867. Basically modest, he had refused to be buried in the Abbey of Westminster (where a plate, not far from the tomb of Isaac Newton, nevertheless his memory celebrates) and its tomb is with the cemetery of Highgate to London.
Its greater work related to electricity. In 1821, after the discovery of the phenomenon of electromagnetism by the Danish chemist Ørsted, Faraday builds two apparatuses to produce what it called an electromagnetic rotation : the continuous circular motion of a magnetic force around a wire, makes the demonstration of an electrical motor of it.
Ten years later, in 1831, it began long series of experiments during which it discovered electromagnetic induction. These experiments form the base of modern electromagnetic technology. In its work on the D.C. current, Faraday showed that the load is only outside one conductor charged and that this one does not have any effect on what can be located inside. This is the effect of shielding which is used in the Faraday screen room.
It was one of the principal founders of electrochemistry as a scientific discipline. In 1833, it introduces the terms of anode, cathode, anion, cation and ions (without to know the concept of electric current discovered later by André Marie Ampère).
It gave its name to the farad, an electric unit of capacity, like with an electric charge, the constant of Faraday. Its portrait is also reproduced on the English tickets of 20 books.
It also gave its name to the instability of Faraday, highlighted in 1831, started when a liquid bath is vibrated vertically with a sufficiently important amplitude. When this instability is started, the surface of the liquid reorganises and of the waves of surface subharmonics appear.
Faraday carries out its first chemistry experiments whereas he is assistant of Humphry Davy. By studying chlorine he discovers two new carbon chlorides. He leads experiments on the overflowing of gases, a phenomenon identified by John Dalton and whose importance will be clarified by Thomas Graham and Joseph Loschmidt. It makes a success of the liquefaction of some natural gases, of which chlorine. It analyses various steel alloys and obtains new types of glasses of optical use. One of them will become important for science since it is thanks to him that Faraday identifies the rotation of the plan of polarisation of the light when glass is placed in a magnetic field. It also sticks to the popularisation of the methods of analysis in chemistry.
One him must have still developed a rudimentary model of gas-burner which will become the Bunsen burner, thereafter universally used in the laboratories.
Faraday discovers, inter alia chemical substances, benzene and invents the system of the number of oxidation. In 1820, Faraday makes a success of the first synthesis of made up of carbon and chlorine, C2Cl6 and C2Cl4, results which it publishes the following year. Faraday defines the composition of the chlorine clathrate which had been discovered by Humphry Davy in 1810.
Faraday is the first to mention the existence of what will be known under the term of nanoparticules metal. In 1847, it observes that the optical properties of gold colloid differ from those of pure metal, observation which one could regard as the birth of the nanosciences.
The mentor and sponsor of Faraday were John "Mad Jack" Fuller, who created "Fullerian Professorship" of chemistry at Royal the Institution. Faraday was the most famous first and of the holders of this station for which it was appointed for life. Royal Society decrees the Copley medal in 1832 and 1838, and the Rumford Medal to him in 1846. He is also prize winner of Royal Medal in 1835 and 1846.Faraday was also member of the Academy of Science in France : elected official corresponding for the section of chemistry on 22 September 1823, then associated foreigner on 23 December 1844.

Hendrik wade Bode



Hendrik Wade Bode
Birth : December 24th, 1905 Madison, Wisconsin, the United States
Death, June 21st, 1982 (76 years), Cambridge, Massachusetts, the United States
Residence, Cambridge, Massachusetts
Nationality : American
Fields : Regulation, Physics, Mathematics, Telecommunications
University : Ohio State University, Bell Labs Harvard University
Famous for : Diagrams of Bode
Distinctions : Presidential medal of the merit, Edison Medal
Hendrik Wade Bode (December 24th, 1905 - June 22nd, 1982) is an engineer, researcher and American inventor of Dutch origin. Pioneer of the modern regulation and telecommunications, it revolutionized these fields as well in their contents as in their methods of application.
Its search had an impact on many other fields of engineering, and posed the foundations of recent innovations such as computers, robots or cellphones.
Recognized for a long time in the scientific world, it is more particularly known students to have developed the diagrams of Bode, a method of representation of the amplitude and phase of a system.
Education
Bode was born in Madison, Wisconsin, his ⁄ her father is teaching and member of the University of Illinois with Urbana-Champaign. Early, it leaves the college at 14 years and tries to integrate the University of Illinois which refuses it because of its young age. Several tens of years later, this same university will give a science honorary doctorate to him.
It is finally accepted at the University of the State of Ohio, where his ⁄ her father also teaches. It obtains Bachelor of Arts of Mathematics in 1924, at the age of 19 years, and Master of Arts in 1926. After obtaining its diploma, there remains still a year in its university as assistant.
Beginnings at the Bell Labs
At its exit of the university, it is recruited by the Bell Labs in New York, where it begins as designer from electronic filters. In 1929, it is assigned with the Group of Mathematical Search of the Bell Labs, where it is shown particularly gifted in its search on its application and electronic network analysis to telecommunications. Encouraged by the Bell Labs, it integrates the Columbia University where it obtains a doctorate of physics in 1935.
In 1938, it develops the diagrams of Bode. Its work on the systems of feedback led to new methods of analysis of the stability of a system. These methods make it possible to the engineers studied stability in the temporal field by using the concepts of gain and dephasing in the frequential field, using these famous diagrams from now on. Its methods of analysis in the frequential field are much simpler and rapids that the study in the temporal field used hitherto. Its work provides to the engineers at the same time a method of analysis of simple and intuitive stability and a tool of design of systems which is as popular today as he was revolutionist at the time.
Second world war and new inventions
With the approach of the Second world war, Bode directs its search towards military applications, a choice which will follow it until the end of its career. It engages with the service of its country near the National Defense Research Committee (NDRC) where its role is to conceive automatic anti-aircraft control systems. Information radar is used to provide data on the position of the enemy air apparatuses, which are then retransmises with the servomechanisms of anti-aircraft artillery, thus allowing to improve the ballistic follow-up of the air targets. In other words, to automate the anti-aircraft shooting using a radar. The servo-motors used are at the same time supplied with electrical energy and hydraulics, the latter being mainly used to operate heavy artillery.
First loop of remote control and weapons robotized
The radar is blocked on the target and its data are transmitted wireless-aware to a receiver on the ground which is connected to the system of regulation of the servomechanisms of artillery. This makes it possible to modify with precision the angular position of the servos and to maintain it sufficiently a long time to draw towards the coordinates calculated from the target and to cut down it.
The calculation of the coordinates is ensured by Director T-10, a kind of computer electric called thus because it is used to direct (direct) the gun according to the air target. It also calculates the mean velocity of the target according to the information of position provided by the radar and predicted its future position while being based on its supposed flight trajectory, in general a linear function of time. This system functions like an early version of the modern models of anti-aircraft missiles. The statistical analysis is also used to help with the calculation of the exact position of the enemy apparatus and to filter the data received on the target possibly deteriorated by variations of the signal or noise.
Bode thus carried out the first loop of feedback wireless telegraphy of the history of the automated control systems, by combining communication wireless telegraphies, computers electric, statistical calculation and theory of regulation of the control systems.
A robot was born
The result of this multidisciplinary association, the artillery gun automated, can also be regarded as a robotized weapon. This model indeed comprises all the elements of concepts to come such as information processing, automatism, artificial intelligence.

Harry Nyquist



Birth date : February 7th, 1889
Birthplace : Nilsby, Sweden
Death : April 4th, 1976
Place of death : Harlingen, Texas
Immigration : The USA in 1907
Study : Northern university Dakota in 1912
Diploma : a doctorate in physics university of yale in 1917
It was born in Nilsby in Sweden. He emigrated towards the United States in 1907 and entered to the university of North Dakota in 1912. Five years later, it was accepted as doctor in physics at the Yale university. After having worked of 1917 to 1934 at ATT, it left for the Bell Laboratories.
In Beautiful Labs, it made search on the thermal noise also called noise of Johnson-Nyquist and on the stability of the looped amplifiers.
Its theoretical work on the determination of the bandwidth requirement to the transmission of information, poses the bases for the searchs for Claude Shannon which will bring the information theory.
In 1927, Nyquist determines that an analog signal must be sampled with at least twice more the high frequency the component if one wants to convert it into a corresponding numeric signal. This result is known under the name of theorem of sampling of Nyquist-Shannon.

Claude Shannon



Name of birth : Claude Elwood Shannon
Birth : April 30th, 1916
Birthplace : Petoskey Michigan, the United States
Death February 24th, 2001
Place of death : Medford, Massachusetts, the United States
Nationality : American
Profession : Engineer, Researcher
Founder of the information theory, is an electrical engineer and American mathematician. It is one of the fathers, if it is not the founding father, of the information theory. Its name is attached to a famous diagram of Shannon very much used in social sciences, which he constantly repudiated.
Biography
He studies electrical engineering and mathematics at the University of Michigan in 1932. He off uses in particular the Boolean algebra for his control supported in 1938 in Massachusetts Institute Technology (MIT). He explains there how to build relay machines by using the Boolean algebra to describe the state of the relays (1 : closed, 0 : opened).
Shannon works twenty years with MIT, of 1958 to 1978. Parallel to its academic activities, he also works at the Bell Laboratories of 1941 to 1972.
Its work
During the Second world war, Shannon works for the secret services of the army, in cryptography, charged to locate in an automatic way in the enemy code the meaning parts hidden in the middle of jamming. Its work is exposed in a secret report/ratio.
The diagram of Shannon
To describe the communication between machines, the article of 1948 and delivers it of 1949 begin both with a diagram which consequently knew an astonishing posterity in Information sciences and communication, so much so that Shannon was astonished some and dissociated some.
In the article as in the book, it popularizes the use of the word bit like measures elementary numerical information. John Tukey was nevertheless the first to use the term. More precisely, the bit indicates the number of binary digits necessary to code a quantity of information. Thus, at least 1 is needed bit or 1 Shannon to code two states.
More generally, if P is the number of possible states, the minimum number of bits N necessary to code them all checks : 2(n-1) < P ≤ 2n
In an ideal case where all information available is used, P = 2n.
The relation of Shannon
In the field of telecommunications, the relation of Shannon makes it possible to calculate the valence or maximum number of states in disturbed medium :
That is to say S the signal, NR noise : n = √(1 + S/N)
There is then the maximum flow : Hlog2 (1 + S/N)
This result is independent the speed of sampling and of the number of level of a sample (the valence).

Ferdinand Braun



Go back to nassance : June 6th, 1850
Birthplace : Fulda, Grand Duchy of Hesse
Go back to death : April 20th, 1918
Place of death : New York
Nationality : Allemande
University : University of Karlsruhe, University of Marbourg, University of Strasbourg, University of Tubingen, University of Wurzburg
Diploma : University of Marbourg and Université of Berlin
Famous : wireless telegraphy
Distinctions: Nobel Prize of physics
Biography
It supported a thesis under the direction of Hermann Ludwig von Helmholtz in 1872 in Berlin. It comes first once to the university from Strasbourg, for two years in 1880 as invited professor, it returns definitively, in 1895, as directing professor of the Institute of Physics. It goes to New York in 1915 to testify in a lawsuit in recognition to patent in radioelectricity. It is stopped and retained for its German nationality by the American authorities and dies before the end of the war, in 1918.
Work
Especially interested physicist by fundamental physics, several of its work were at the origin of interesting applications.
As of the 25 years age, in 1874, it establishes that crystal (lead sulfide) does not respect the law of Ohm: under certain conditions it does not conduct the electricity in the same way according to whether one applies a tension in a direction or another.
Professor at the university of Strasbourg (it had Jonathan Zenneck as raises), it was interested in the fast electric phenomena and to be able to study them, it developed in 1897 a particular cathode tube, known as tube of Braun. Its invention led quickly to the development of the oscilloscope, which later was going to make it possible to build the cathode tubes of the television sets, then first screens of computers. Braun used its invention in the company Professor Braun Telegrafen GmbH which will become later Telefunken AG.
It launches out in 1898 in the transmission without wire (TSF). At that time, the radio operator devices of Guglielmo Marconi have a limited range to 15 km, insufficient for practical applications. In these radios, without amplifier, the antenna is an integral part of the circuit of agreement. Using its knowledge in physics, Braun separates the antenna from the circuit of agreement by using between them an inductive coupling. It removes the spark of the circuits thus limiting the losses of energy and increasing the sensitivity. It patents, in 1899, its system which makes it possible to cover in Cuxhaven a distance of 62 km.
In 1906, it used its knowledge of the properties of conduction of crystal to imagine a rectifier, which one can regard as the ancestor of the modern diode, which allowed the rise of the station crystal.
The Nobel Prize of physics of 1909 was allotted to him, with Guglielmo Marconi, for its work on the wireless telegraphy.

Max Wien



Birth date: December 25th, 1866
Birth place: Königsberg, Prussia
Go back to death: February 24th, 1938
Place of death: Iéna, Weimar Republic
Nationality: German
Profession: Physicist
Institution: University of Iéna, University of Göttingen, Humboldt University of Berlin
Famous: Bridge of Wien
Max Wien, was a German physicist and the director of the Institute of Physics of the University of Iéna.
He invented Löschfunkensender (a generator of slightly quenched electromagnetic oscillations, used for example on Titanic) between 1906 and 1909 and the oscillator with bridge of Wien in 1891. However, Wien did not have the means of developing an amplifier electronic (William Hewlett, cofounder of Hewlett-Packard, carried it out in 1939).

John Frederic Daniel



Birth date: March 12th, 1790
Birth place: London
Go back to death: March 13rd, 1845
Place of death: London
Profession: chemist and physicist
University: Royal college, University of Edinbourgh, Continental Gas-company
Invention: crush Daniell, hygrometer, pyrometer, barometer
Distinctions: the Rumford medal, the Copley medal, the Royal medal
John Frederic Daniell is a chemist and British physicist. Its family defined it as an artist. Daniel is born in London in 1790. In 1831, he becomes the first chemistry teacher of the Royal College of London which has just been created.
He invents a hygrometer with condensation, the Daniell hygrometer as well as a recording pyrometer. In 1830 it builds a barometer with water in the hall of the Royal company which it uses to make of many observations. A method of production of coal gas starting from spirits of turpentine and resin is used during some time in New York.
It is for the invention of the pile Daniell, a new type of battery which one remembers him most frequently nowadays.
He dies suddenly of a crisis of apoplexy in London during a meeting of the Royal council of the Company in 1845.
Daniel receives the Rumford medal in 1832, the Copley medal in 1837 and the Royale medal in 1842. A crater on the Moon bears its name.

Joseph Stefan


Birth date: March 24th, 1935
Birthplace: Sveti Peter, Austria
Go back to death: January 7th, 1893
Place of death: Vienna
Profession: physicist and mathematician
Institution: University of Vienna, Institute of physics, Academy of Vienna
Diploma: mathematics and phyisque
Distinctions: the first Lieben price
Joseph Stefan, it was born in the village from Saint Peter (Sveti Peter) close to Klagenfurt (Celovec) in Austria-Hungary, today in Austria. Its family was modest: his ⁄ her father was workman milling machine operator and his ⁄ her mother served as good. The talent of Stefan appeared as of the elementary school then with the college of Klagenfurt. After having thought of being made monk, it leaves for Vienna in 1853 to study mathematics and physics.
Beside its scientific studies, he wrote poems and literary works in Slovenien.
He receives his diploma of mathematics and physics in 1857, sign physics at the University of Vienna and becomes director of the Institute of physics in 1866, then vice-president of the Academy of Vienna.
Its work in optics, in particular on the birefringence of quartz, is worth the first Lieben price to him in 1865.
It is honoured in many universities abroad, writes more than 80 scientific articles of which its publication of 1879 on the radiation of the black body where it states the law: M = sT4
It is known under the name of law of Stefan or more usually law of Stefan-Boltzmann bus it is his pupil Ludwig Boltzmann who will provide the theoretical justification of it.
Starting from this law, Stefan determines the temperature of the surface of the sun (5430°C). It determines the thermal conductivity of many gases, as well as the conduction of heat by the fluids.
He also works on electromagnetism following work of Maxwell, to which he brings several improvements.
Slovenia honoured it by baptizing Institut Jožef Stefan her greater establishment of research located at Ljubljana.

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