James Clerk Maxwell Discovery. Scientific discoveries of the 19th century

James Clerk Maxwell (1831-79) - English physicist, creator of classical electrodynamics, one of the founders of statistical physics, organizer and first director (since 1871) of the Cavendish Laboratory, predicted the existence of electromagnetic waves, put forward the idea of the electromagnetic nature of light, established the first statistical law - the law of distribution of molecules by velocities, named after him.

When a phenomenon can be described as a special case of some general principle applicable to other phenomena, then they say that this phenomenon has received an explanation.

Maxwell James Clerk

Developing the ideas of Michael Faraday, he created the theory of the electromagnetic field (Maxwell's equations); introduced the concept of displacement current, predicted the existence of electromagnetic waves, put forward the idea of the electromagnetic nature of light. Established a statistical distribution named after him. Investigated the viscosity, diffusion and thermal conductivity of gases. Maxwell showed that the rings of Saturn are composed of separate bodies. Proceedings on color vision and colorimetry (Maxwell's disk), optics (Maxwell's effect), theory of elasticity (Maxwell's theorem, Maxwell-Cremona diagram), thermodynamics, history of physics, etc.

Family. Years of study

James Maxwell was born June 13, 1831, in Edinburgh. He was the only son of the Scottish nobleman and lawyer John Clerk, who, having inherited the estate of a relative's wife, née Maxwell, added this name to his surname. After the birth of their son, the family moved to South Scotland, to their own estate Glenlar (“Shelter in the valley”), where the boy spent his childhood.

Of all the hypotheses… choose the one that does not prevent further thinking about the things under investigation

Maxwell James Clerk

In 1841, his father sent James to a school called Edinburgh Academy. Here, at the age of 15, Maxwell wrote his first scientific article, "On the Drawing of Ovals." In 1847 he entered the University of Edinburgh, where he studied for three years, and in 1850 moved to the University of Cambridge, graduating in 1854. By this time, James Maxwell was a first-class mathematician with a superbly developed intuition of a physicist.

Creation of the Cavendish Laboratory. Teaching work

After graduation, James Maxwell was left in Cambridge for teaching work. In 1856 he received a professorship at Marishall College at the University of Aberdeen (Scotland). In 1860 he was elected a member of the Royal Society of London. In the same year he moved to London, accepting an offer to take the post of head of the department of physics at King's College, London University, where he worked until 1865.

Returning to Cambridge University in 1871, Maxwell organized and headed the first specially equipped laboratory for physical experiments in Great Britain, known as the Cavendish Laboratory (after the English scientist Henry Cavendish). The formation of this laboratory, which at the turn of the 19-20 centuries. turned into one of the largest centers of world science, Maxwell devoted the last years of his life.

To conduct scientific work quite correctly through systematic experiments and accurate demonstrations, strategic art is required.

Maxwell James Clerk

In general, little is known about the life of Maxwell. Shy, modest, he strove to live in solitude and did not keep diaries. In 1858, James Maxwell married, but family life, apparently, was unsuccessful, exacerbated his unsociableness, alienated him from his former friends. There is an assumption that many important materials about the life of Maxwell were lost during the fire of 1929 in his Glenlar house, 50 years after his death. He died of cancer at the age of 48.

Scientific activity

Maxwell's unusually wide scope of scientific interests covered the theory of electromagnetic phenomena, the kinetic theory of gases, optics, the theory of elasticity, and much more. One of his first works was research on the physiology and physics of color vision and colorimetry, begun in 1852. In 1861, James Maxwell first obtained a color image by projecting red, green, and blue transparencies onto a screen at the same time. This proved the validity of the three-component theory of vision and outlined ways to create a color photograph. In the works of 1857-59, Maxwell theoretically investigated the stability of the rings of Saturn and showed that the rings of Saturn can be stable only if they consist of unrelated particles (bodies).

In 1855, D. Maxwell began a cycle of his main works on electrodynamics. The articles "On Faraday's lines of force" (1855-56), "On physical lines of force" (1861-62), "The dynamical theory of the electromagnetic field" (1869) were published. The research was completed with the publication of the two-volume monograph Treatise on Electricity and Magnetism (1873).

Every great man is one of a kind. In the historical procession of scientists, each of them has his own specific task and his own specific place.

Maxwell James Clerk

Creation of the electromagnetic field theory

When James Maxwell began researching electrical and magnetic phenomena in 1855, many of them had already been well studied: in particular, the laws of interaction of stationary electric charges (Coulomb's law) and currents (Ampère's law) were established; it has been proved that magnetic interactions are interactions of moving electric charges. Most scientists of that time believed that the interaction is transmitted instantly, directly through the void (long-range theory).

A decisive turn towards the theory of short-range action was made by Michael Faraday in the 1930s. 19th century According to Faraday's ideas, an electric charge creates an electric field in the surrounding space. The field of one charge acts on another, and vice versa. The interaction of currents is carried out by means of a magnetic field. Faraday described the distribution of electric and magnetic fields in space with the help of lines of force, which, in his opinion, resemble ordinary elastic lines in a hypothetical medium - the world ether.

Maxwell fully accepted Faraday's ideas about the existence of an electromagnetic field, that is, about the reality of processes in space near charges and currents. He believed that the body cannot function where it does not exist.

The first thing D.K. Maxwell - gave the ideas of Faraday a rigorous mathematical form, so necessary in physics. It turned out that with the introduction of the concept of a field, the laws of Coulomb and Ampere began to be expressed most fully, deeply and gracefully. In the phenomenon of electromagnetic induction, Maxwell saw a new property of fields: an alternating magnetic field generates in empty space an electric field with closed lines of force (the so-called vortex electric field).

The next, and last, step in the discovery of the basic properties of the electromagnetic field was taken by Maxwell without any reliance on experiment. He made a brilliant guess that an alternating electric field generates a magnetic field, like an ordinary electric current (hypothesis of the displacement current). By 1869, all the basic laws governing the behavior of the electromagnetic field had been established and formulated as a system of four equations, called Maxwell's equations.

The real center of science is not volumes of scientific works, but the living mind of a person, and in order to advance science, it is necessary to direct human thought into a scientific channel. This can be done in various ways: by announcing a discovery, defending a paradoxical idea, or inventing a scientific phrase, or laying out a system of doctrine.

Maxwell James Clerk

Maxwell's equations are the basic equations of classical macroscopic electrodynamics that describe electromagnetic phenomena in arbitrary media and in vacuum. Maxwell's equations were obtained by J.K. Maxwell in the 60s. 19th century as a result of generalization of the laws of electrical and magnetic phenomena found from experience.

A fundamental conclusion followed from Maxwell's equations: the finiteness of the propagation velocity of electromagnetic interactions. This is the main thing that distinguishes the theory of short-range action from the theory of long-range action. The speed turned out to be equal to the speed of light in vacuum: 300,000 km/s. From this Maxwell concluded that light is a form of electromagnetic waves.

Works on the molecular-kinetic theory of gases

The role of James Maxwell in the development and development of the molecular-kinetic theory (the modern name is statistical mechanics) is extremely great. Maxwell was the first to make a statement about the statistical nature of the laws of nature. In 1866 he discovered the first statistical law - the law of the distribution of molecules by velocities (Maxwell distribution). In addition, he calculated the values of the viscosity of gases depending on the velocities and mean free path of molecules, and derived a number of thermodynamic relations.

Maxwell's distribution - the distribution of the velocities of the molecules of the system in a state of thermodynamic equilibrium (provided that the translational motion of the molecules is described by the laws of classical mechanics). Established by J. K. Maxwell in 1859.

Maxwell was a brilliant popularizer of science. He wrote a number of articles for the Encyclopædia Britannica and popular books: The Theory of Heat (1870), Matter and Motion (1873), Electricity in Elementary Presentation (1881), which were translated into Russian; gave lectures and reports on physical topics for a wide audience. Maxwell also showed great interest in the history of science. In 1879 he published the works of G. Cavendish on electricity, providing them with extensive comments.

Appreciation of Maxwell's work

The works of the scientist were not appreciated by his contemporaries. Ideas about the existence of an electromagnetic field seemed arbitrary and unproductive. Only after Heinrich Hertz experimentally proved the existence of the electromagnetic waves predicted by Maxwell in 1886-89 did his theory gain general recognition. It happened ten years after Maxwell's death.

After experimental confirmation of the reality of the electromagnetic field, a fundamental scientific discovery was made: there are different types of matter, and each of them has its own laws that cannot be reduced to the laws of Newtonian mechanics. However, Maxwell himself was hardly clearly aware of this and at first he tried to build mechanical models of electromagnetic phenomena.

The American physicist Richard Feynman said excellently about the role of Maxwell in the development of science: “In the history of mankind (if you look at it, say, in ten thousand years), the most significant event of the 19th century will undoubtedly be the discovery by Maxwell of the laws of electrodynamics. Against the background of this important scientific discovery, the American Civil War in the same decade will look like a provincial incident.

James Maxwell passed away November 5, 1879, Cambridge. He is buried not in the tomb of the great people of England - Westminster Abbey - but in a modest grave next to his beloved church in a Scottish village, not far from the family estate.

James Clerk Maxwell - quotes

To conduct scientific work quite correctly through systematic experiments and accurate demonstrations, strategic skill is required.

Of all the hypotheses, choose the one that does not prevent further thinking about the things under study.

For the development of science, it is required in every given epoch not only that people think in general, but that they concentrate their thoughts on that part of the vast field of science, which at a given time requires development.

MAXWELL James Clerk (Maxwell James Clerk (13. VI.1831 - 5. XI.1879) - English physicist, member of the Edinburgh (1855) and London (1861) Royal Society. R. in Edinburgh. He studied at Edinburgh (1847-50) and Cambridge (1850-54) high fur boots. At the end of the last short period he taught at Trinity College, in 1856 - 60 - professor at Aberdeen University, in 1860 - 65 - King's College London, from 1871 - the first professor of experimental physics at Cambridge. Under his leadership, the famous Cavendish Laboratory in Cambridge was created, which he headed until the end of his life.

Works are devoted to electrodynamics, molecular physics, general statistics, optics, mechanics, theory of elasticity. Maxwell's most significant contribution was made to molecular physics and electrodynamics.
In the kinetic theory of gases, one of the founders of which he is, he established in 1859 a statistical law describing the distribution of gas molecules by velocities (the Maxwell distribution). In 1866 he gave a new derivation of the velocity distribution function of molecules, based on consideration of forward and backward collisions, developed the theory of transfer in a general form, applying it to the processes of diffusion, heat conduction, and internal friction, and introduced the concept of relaxation time.
In 1867, the first showed the statistical nature of the second law of thermodynamics ("Maxwell's demon"), in 1878 he introduced the term "statistical mechanics".

Maxwell's greatest scientific achievement is the electromagnetic field theory he created in 1860–65, which he formulated as a system of several equations (Maxwell's equations) expressing all the basic laws of electromagnetic phenomena (the first differential field equations were written down by Maxwell in 1855–56). In his theory of the electromagnetic field, Maxwell used (1861) a new concept - displacement current, gave (1864) a definition of the electromagnetic field and predicted (1865) a new important effect: the existence of electromagnetic radiation (electromagnetic waves) in free space and its propagation in space at the speed of light . The latter gave him reason to consider (1865) light as one of the types of electromagnetic radiation (the idea of the electromagnetic nature of light) and to reveal the connection between optical and electromagnetic phenomena. Theoretically calculated the pressure of light (1873). Set the ratio ε = n 2 (1860).
Predicted the effects of Stewart - Tolman and Einstein - de Haas (1878), skin effect.

He also formulated a theorem in the theory of elasticity (Maxwell's theorem), established relationships between the main thermophysical parameters (Maxwell's thermodynamic relations), developed the theory of color vision, studied the stability of Saturn's rings, showing that the rings are not solid or liquid, but are a swarm of meteorites.
Designed a number of devices.
He was a famous popularizer of physical knowledge.
He published for the first time (1879) the manuscripts of G. Cavendish .

Compositions:

Selected Writings on Electromagnetic Field Theory. - State publishing house of technical and theoretical literature. M., 1952 (Series "Classics of Natural Science").
Speeches and Articles. State publishing house of technical and theoretical literature. M.-L., 1940 (Series "Classics of Natural Science").
Matter and Motion. - Izhevsk, Research Center "Regular and Chaotic Dynamics", 2001.
Treatise on electricity and magnetism. - M., Nauk, 1989 (Series "Classics of Science"). Volume 1. Volume 2.
Excerpts from works:

Literature:

V. Kartsev. Maxwell. Life of wonderful people. Young guard; Moscow; 1974

Movies:

Many scientific publications and journals have recently published articles about achievements in physics and modern scientists, and publications about physicists of the past are rare. We would like to correct this situation and recall one of the outstanding physicists of the last century, James Clerk Maxwell. This is a famous English physicist, the father of classical electrodynamics, statistical physics and many other theories, physical formulas and inventions. Maxwell became the founder and first head of the Cavendish Laboratory.

As you know, Maxwell came from Edinburgh and was born in 1831 into a noble family, which had a relationship with the Scottish surname Clerks of Penicuik. Maxwell's childhood was spent on the Glenlar estate. James' ancestors were politicians, poets, musicians and scientists. Probably, a penchant for the sciences was inherited by him.

James was brought up without a mother (since she died when he was 8 years old) by a father who cared for the boy. The father wanted his son to study natural sciences. James immediately fell in love with technology and quickly developed practical skills. Little Maxwell took the first lessons at home with perseverance, since he did not like the harsh methods of education used by the teacher. Further training took place in an aristocratic school, where the boy showed great mathematical abilities. Maxwell especially liked geometry.

To many great people, geometry seemed to be an amazing science, and even at the age of 12 he spoke of a geometry textbook as a holy book. Maxwell loved geometry as well as other scientific luminaries, but he had a bad relationship with his schoolmates. They constantly came up with offensive nicknames for him and one of the reasons was his ridiculous clothes. Maxwell's father was considered an eccentric and bought his son clothes that made him smile.

Maxwell already in childhood showed great promise in the field of science. In 1814 he was sent to study at Edinburgh Grammar School, and in 1846 he was awarded a medal for merit in mathematics. His father was proud of his son and was given the opportunity to present one of his son's scientific papers before the board of the Edinburgh Academy of Sciences. This work concerned the mathematical calculations of elliptical figures. Then this work was called "On the drawing of ovals and on ovals with many tricks." It was written in 1846 and published to the masses in 1851.

Maxwell began to study physics intensively after transferring to the University of Edinburgh. Kalland, Forbes and others became his teachers. They immediately saw in James a high intellectual potential and an irresistible desire to study physics. Prior to this period, Maxwell had dealt with certain branches of physics and studied optics (he devoted a lot of time to the polarization of light and Newton's rings). In this he was helped by the famous physicist William Nicol, who at one time invented the prism.

Of course, other natural sciences were not alien to Maxwell, and he paid special attention to the study of philosophy, the history of science and aesthetics.

In 1850 he entered Cambridge, where Newton had once worked, and in 1854 received his academic degree. After that, his research touched the field of electricity and electrical installations. And in 1855 he was granted membership in the council of Trinity College.

Maxwell's first significant scientific work was On Faraday's Lines of Force, which appeared in 1855. At one time, Boltzmann said about Maxwell's article that this work has a deep meaning and shows how purposefully the young scientist approaches scientific work. Boltzmann believed that Maxwell not only understood the issues of natural science, but also made a special contribution to theoretical physics. Maxwell outlined in his article all the trends in the evolution of physics for the next few decades. Later, Kirchhoff, Mach and. came to the same conclusion.

How was the Cavendish Laboratory formed?

After completing his studies at Cambridge, James Maxwell remained here as a teacher and in 1860 he became a member of the Royal Society of London. At the same time, he moved to London, where he was given a position as head of the physics department at King's College, University of London. He worked in this position for 5 years.

In 1871, Maxwell returned to Cambridge and created the first laboratory in England for research in the field of physics, which was called the Cavendish Laboratory (in honor of Henry Cavendish). Maxwell devoted the rest of his life to the development of the laboratory, which became a real center of scientific research.

Little is known about Maxwell's life, as he kept no notes or diaries. He was a modest and shy person. Maxwell died at the age of 48 from cancer.

What is the scientific legacy of James Maxwell?

Maxwell's scientific activity covered many areas in physics: the theory of electromagnetic phenomena, the kinematic theory of gases, optics, the theory of elasticity, and others. The first thing that interested James Maxwell was the study and conduct of research in the physiology and physics of color vision.

Maxwell for the first time managed to get a color image, which was obtained due to the simultaneous projection of the red, green and blue range. By this, Maxwell once again proved to the world that the color image of vision is based on a three-component theory. This discovery marked the beginning of the creation of color photographs. In the period from 1857-1859, Maxwell was able to investigate the stability of Saturn's rings. His theory says that the rings of Saturn will be stable only under one condition - the unconnectedness of particles or bodies.

From 1855, Maxwell paid special attention to work in the field of electrodynamics. There are several scientific works of this period "On Faraday's lines of force", "On physical lines of force", "Treatise on electricity and magnetism" and "Dynamical theory of the electromagnetic field".

Maxwell and the theory of the electromagnetic field.

When Maxwell began to study electrical and magnetic phenomena, many of them were already well studied. Was created Coulomb's law, Ampère's law, it was also proved that magnetic interactions are connected by the action of electric charges. Many scientists of that time were supporters of the long-range theory, which states that the interaction occurs instantly and in empty space.

The main role in the theory of short-range action was played by the studies of Michael Faraday (30s of the 19th century). Faraday argued that the nature of the electric charge is based on the surrounding electric field. The field of one charge is connected with the neighboring one in two directions. The currents interact with the help of a magnetic field. According to Faraday, magnetic and electric fields are described by him in the form of lines of force, which are elastic lines in a hypothetical medium - in the ether.

Maxwell supported Faraday's theory of the existence of electromagnetic fields, that is, he was a supporter of emerging processes around charge and current.

Maxwell explained Faraday's ideas in a mathematical form, which physics really needed. With the introduction of the field concept, the laws of Coulomb and Ampere became more convincing and deeply meaningful. In the concept of electromagnetic induction, Maxwell was able to consider the properties of the field itself. Under the action of an alternating magnetic field in empty space, an electric field with closed lines of force is generated. This phenomenon is called a vortex electric field.

Maxwell's next discovery was that an alternating electric field could generate a magnetic field, much like an ordinary electric current. This theory was called the displacement current hypothesis. In the future, Maxwell expressed the behavior of electromagnetic fields in his equations.

Reference. Maxwell's equations are equations describing electromagnetic phenomena in various media and vacuum space, and also refer to classical macroscopic electrodynamics. This is a logical conclusion drawn from experiments based on the laws of electrical and magnetic phenomena.
The main conclusion of Maxwell's equations is the finiteness of the propagation of electrical and magnetic interactions, which delimited the theory of short-range interaction and the theory of long-range interaction. Velocity characteristics approached the speed of light 300,000 km/s. This gave Maxwell reason to argue that light is a phenomenon associated with the action of electromagnetic waves.

Molecular-kinetic theory of Maxwell's gases.

Maxwell contributed to the study of molecular kinetic theory (now this science is called statistical mechanics). Maxwell was the first to come up with the idea of the statistical nature of the laws of nature. He created the law of distribution of molecules by speeds, and he also managed to calculate the viscosity of gases in relation to speed indicators and the mean free path of gas molecules. Also, thanks to the work of Maxwell, we have a number of thermodynamic relations.

Reference. The Maxwell distribution is a theory of the velocity distribution of the molecules of a system under conditions of thermodynamic equilibrium. Thermodynamic equilibrium is the condition for the translational motion of molecules described by the laws of classical dynamics.

Maxwell had many scientific works that were published: "The Theory of Heat", "Matter and Motion", "Electricity in Elementary Presentation" and others. Maxwell not only moved science into the period, but was also interested in its history. At one time he managed to publish the works of G. Cavendish, which he supplemented with his comments.

What will the world remember about James Clerk Maxwell?

Maxwell was active in the study of electromagnetic fields. His theory of their existence did not receive worldwide recognition until a decade after his death.

Maxwell was the first to classify matter and assign its own laws to each, which were not reduced to the laws of Newtonian mechanics.

Many scientists have written about Maxwell. The physicist R. Feynman said about him that Maxwell, who discovered the laws of electrodynamics, looked through the centuries into the future.

Epilogue. James Clerk Maxwell died November 5, 1879 in Cambridge. He was buried in a small Scottish village near his favorite church, which is located not far from his family estate.

James Maxwell was born on June 13, 1831 in the capital of Scotland, the city of Edinburgh, in the family of a lawyer and hereditary nobleman John Clerk Maxwell. James spent his childhood on the family estate in South Scotland. His mother died early, and the boy was raised by his father. It was he who instilled in James a love of technical sciences. In 1841 he entered the Edinburgh Academy. Then, in 1847, he studied at the University of Edinburgh for three years. Here Maxwell studies and develops the theory of elasticity, puts scientific experiments. In 1850 - 1854. studied at the University of Cambridge, where he graduated with a bachelor's degree.

After completing his studies, James remains to teach at Cambridge. At this time, he begins work on the theory of colors, which later formed the basis of color photography. Maxwell also becomes interested in electricity and the magnetic effect.

In 1856, James Maxwell became professor at Marischal College in Aberdeen, Scotland, where he worked until 1860. In June 1858, Maxwell married the daughter of the principal of the college. Working in Aberdeen, James is working on a treatise On the Stability of the Movement of the Rings of Saturn (1859), recognized and approved by the scientific community. At the same time, Maxwell was developing the kinetic theory of gases, which formed the basis of modern statistical mechanics, and later, in 1866, he discovered the law of molecular velocity distribution, named after him.

In 1860 - 1865. James Maxwell was Professor in the Department of Natural Philosophy at King's College (London). in 1864, his article "The Dynamic Theory of the Electromagnetic Field" was published, which became Maxwell's main work and predetermined the direction of his further research. The scientist was engaged in the problems of electromagnetism until the end of his life.

In 1871, Maxwell returned to the University of Cambridge, where he headed the first laboratory for physical experiments, named after the English scientist Henry Cavendish - the Cavendish Laboratory. There he taught physics and participated in equipping the laboratory.

In 1873, the scientist finally finishes work on the two-volume work Treatise on Electricity and Magnetism, which has become a truly encyclopedic heritage in the field of physics.

The great scientist died on November 5, 1879 from cancer and was buried near the family estate, in the Scottish village of Parton.

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MAXWELL, James Clerk(Maxwell, James Clerk) (1831–1879), English physicist. Born June 13, 1831 in Edinburgh in the family of a Scottish nobleman from a noble family of Clerks. He studied first at Edinburgh (1847-1850), then at Cambridge (1850-1854) universities. In 1855 he became a member of the Council of Trinity College, in 1856-1860 he was a professor at Marishall College, Aberdeen University, from 1860 he headed the department of physics and astronomy at King's College, London University. In 1865, due to a serious illness, Maxwell resigned from the chair and settled in his family estate Glenlar near Edinburgh. He continued to study science, wrote several essays on physics and mathematics. In 1871 he took the chair of experimental physics at the University of Cambridge. He organized a research laboratory, which opened on June 16, 1874 and was named Cavendish - in honor of G. Cavendish.

Maxwell completed his first scientific work while still at school, inventing a simple way to draw oval shapes. This work was reported at a meeting of the Royal Society and even published in its Proceedings. As a member of the Council of Trinity College, he experimented on color theory, acting as a successor to Jung's theory and Helmholtz's theory of the three primary colors. In experiments on mixing colors, Maxwell used a special top, the disk of which was divided into sectors painted in different colors (Maxwell's disk). When the spinning top rotated quickly, the colors merged: if the disk was painted over in the way the colors of the spectrum are located, it seemed white; if one half of it was painted red and the other half yellow, it appeared orange; mixing blue and yellow gave the impression of green. In 1860, Maxwell was awarded the Rumfoord Medal for his work on color perception and optics.

In 1857 the University of Cambridge announced a competition for the best work on the stability of Saturn's rings. These formations were discovered by Galileo at the beginning of the 17th century. and represented an amazing mystery of nature: the planet seemed to be surrounded by three continuous concentric rings, consisting of a substance of an unknown nature. Laplace proved that they cannot be solid. Having carried out a mathematical analysis, Maxwell was convinced that they could not be liquid either, and came to the conclusion that such a structure could be stable only if it consisted of a swarm of unrelated meteorites. The stability of the rings is ensured by their attraction to Saturn and the mutual motion of the planet and meteorites. For this work, Maxwell received the J. Adams Prize.

One of Maxwell's first works was his kinetic theory of gases. In 1859, the scientist made a presentation at a meeting of the British Association, in which he gave the distribution of molecules by velocities (Maxwellian distribution). Maxwell developed the ideas of his predecessor in the development of the kinetic theory of gases by R. Clausius, who introduced the concept of "mean mean free path". Maxwell proceeded from the idea of a gas as an ensemble of perfectly elastic balls moving randomly in a closed space. Balls (molecules) can be divided into groups according to their velocities, while in the stationary state the number of molecules in each group remains constant, although they can leave the groups and enter them. From such a consideration it followed that “particles are distributed according to velocities according to the same law as the observation errors are distributed in the theory of the least squares method, i.e. in accordance with Gaussian statistics." Within his theory, Maxwell explained Avogadro's law, diffusion, heat conduction, internal friction (transport theory). In 1867 he showed the statistical nature of the second law of thermodynamics ("Maxwell's demon").

In 1831, the year of Maxwell's birth, M. Faraday carried out classical experiments that led him to the discovery of electromagnetic induction. Maxwell began to study electricity and magnetism about 20 years later, when there were two views on the nature of electric and magnetic effects. Scientists such as A.M. Ampere and F. Neumann adhered to the concept of long-range action, considering electromagnetic forces as an analogue of gravitational attraction between two masses. Faraday was a proponent of the idea of lines of force that connect positive and negative electric charges, or the north and south poles of a magnet. The lines of force fill the entire surrounding space (the field, in Faraday's terminology) and determine the electrical and magnetic interactions. Following Faraday, Maxwell developed a hydrodynamic model of lines of force and expressed the then known relations of electrodynamics in a mathematical language corresponding to Faraday's mechanical models. The main results of this study are reflected in the work Faraday lines of force (Faraday's Lines of Force, 1857). In 1860–1865, Maxwell created the theory of the electromagnetic field, which he formulated as a system of equations (Maxwell's equations) describing the basic laws of electromagnetic phenomena: the 1st equation expressed Faraday's electromagnetic induction; 2nd - magnetoelectric induction, discovered by Maxwell and based on the concepts of displacement currents; 3rd - the law of conservation of the amount of electricity; 4th - the vortex nature of the magnetic field.

Continuing to develop these ideas, Maxwell came to the conclusion that any changes in the electric and magnetic fields should cause changes in the lines of force penetrating the surrounding space, i.e. there must be impulses (or waves) propagating in the medium. The speed of propagation of these waves (electromagnetic disturbance) depends on the dielectric and magnetic permeability of the medium and is equal to the ratio of the electromagnetic unit to the electrostatic unit. According to Maxwell and other researchers, this ratio is 3×10 10 cm/s, which is close to the speed of light measured seven years earlier by the French physicist A. Fizeau. In October 1861, Maxwell informed Faraday of his discovery that light is an electromagnetic disturbance propagating in a non-conductive medium, i.e. kind of electromagnetic waves. This final stage of research is described in the work of Maxwell Dynamic theory of electromagnetic field (Treatise on Electricity and Magnetism, 1864), and the result of his work on electrodynamics was summed up by the famous Treatise on electricity and magnetism (1873).

The last years of his life, Maxwell was engaged in preparing for printing and publishing the manuscript heritage of Cavendish. Two large volumes were published in October 1879. Maxwell died in Cambridge on November 5, 1879.