Famous Dutch physicist, astronomer and mathematician, creator of the wave theory. Since 1663 he became the first Dutch member of the Royal Society of London. Huygens studied at the University of Leiden (1645-1647) and Breda College (1647-1649), where he studied mathematics and law.

My scientific career Christian Huygens started at the age of 22. Lived in Paris from 1665 to 1681, from 1681 to 1695 - in The Hague. In his honor are named: the craters of the Moon and Mars, a mountain on the Moon, an asteroid, a space probe, a laboratory at Leiden University. Christian native, born April 14, 1629 in the family of a famous, prosperous and successful Privy Councilor Princes of Orange, Constantine Huygens (Heygens). His father was a well-known writer, received an excellent scientific education.

Young Huygens studied mathematics and law at the University of Leiden, after graduating from which he decided to devote his work entirely to science. In 1651 "Discourses on the quadrature of the hyperbola, ellipse and circle" were published. In 1654 - the work "On the determination of the size of the circle", which became his greatest contribution to the development of mathematical theory.

The first glory came to the young Christian after the discovery of the rings of Saturn and the satellite of this planet, Titan. According to historical data, the great Galileo also saw them. Legrange mentioned that Huygens was able to develop the most important discoveries of Galileo. Already in 1657, Huygens received a Dutch patent for the creation of a pendulum clock mechanism.

Above this mechanism last years Galileo worked his life, but could not finish the work because of his blindness. The mechanism invented by Huygens made it possible to create inexpensive pendulum clocks, which were world-wide popular and widespread. Published in 1657, the treatise "On Calculations in the Game of Dice" became one of the first works in the field of probability theory.

Together with R. Hooke, he established two constant points of the thermometer. In 1659 Huygens published the classic work The System of Saturn. In it, he described his observations of the rings of Saturn, Titan, and also described the Orion Nebula and the bands on Mars and Jupiter.

In 1665, Christian Huygens was asked to become chairman of the French Academy of Sciences. He moved to Paris, where he lived, almost without leaving anywhere until 1681. Huygens was engaged in the development of a "planetary machine" in 1680, which became the prototype of the modern planetarium. For this work, he created the theory of continued fractions.

Returning to Holland in 1681, due to the revocation of the Edict of Nantes, Christian Huygens took up optical inventions. From 1681 to 1687 the physicist was engaged in grinding and polishing large lenses with focal lengths of 37-63 meters. In the same period, Huygens designed the eyepiece famous for his name. This eyepiece is still in use today.

The famous treatise of Christian Huygens, "Treatise on Light", is still famous for its fifth chapter. It describes the phenomenon of double refraction in crystals. On the basis of this chapter, the classical theory of refraction in uniaxial crystals has been expounded up to now.

While working on the Treatise on Light, Huygens came very close to discovering the law of universal gravitation. He outlined his reasoning in the appendix "On the Causes of Gravity". The last treatise by Christian Huygens, "Cosmoteoris", was published posthumously, in 1698. The same treatise, on the plurality of worlds and their habitability, was translated into Russian in 1717 by order of Peter I.

Christian Huygens has always been in poor health. A serious illness, with frequent complications and painful relapses, weighed down his last years of life. He also suffered from feelings of loneliness and melancholy. Christian Huygens died in agony on July 8, 1695.

Many of Huygens' works are now of exceptional historical value. His theory of rotating bodies and his enormous contribution to the theory of light are of scientific importance to this day. These theories have become the most brilliant and unusual contributions to modern science.

Optics occupies a special place in science, if only because “light” is a concept both macroscopic and microscopic, the interests of optics, its methods extend from the mega-world to the micro-world, from the Universe to microparticles, and the scientific conclusions obtained either in the study of optical phenomena, or with the help of optical methods and means, they have repeatedly changed ideas about the structure of the world, that is, they had and still have an ideological character.

Even at the first stages of the development of science, in the era of mythology and philosophy, even before the emergence of instrumental optics, the idea of ​​light, vision, the Sun played a significant role in shaping the worldview. There was a mythological, fantastic "optics", in which the Sun was deified, the concepts of vision and light were mixed. The identity of ideas about light and vision persisted until the 17th century. Against the background of the outstanding successes of science in such areas as geodesy, astronomy, mathematics, mechanics, the doctrine of light was modern concepts, ridiculous. This can be explained to a certain extent by the absence of optical instruments that provide images of objects. The first optical system that "separated" light from vision was the camera obscura, which we have already mentioned. The image given by the camera existed separately from the eye. As soon as optical systems that create an image appeared, optics as a science of vision (in the original sense) began to turn into a science of light, or, in a broader sense, the science of radiation, its propagation and interaction with matter. Optical instrumentation appears in technology, and to this day creates conditions for the development of many branches of science and technology.

Optical experiments have raised theoretical problems in the field of optics to a new level, the most important of which are the problems of the nature of light and the speed of its propagation. In the formulation and solution of these problems, a prominent place belongs to Francesco Grimaldi (1618-1663), Olaf Roemer (1644-1710), Christian Huygens (1629-1695), Robert Hooke (1635-1703).

Among the achievements of optics of the XVII century. a striking event was the discovery of diffraction, which belongs to the Italian scientist Grimaldi.

Francesco Maria Grimaldi was born into the family of a silk merchant. From a young age, Grimaldi joined the Jesuit order and for many years studied at several Jesuit schools and universities in Italy, and then he taught mathematics and philosophy at the Jesuit college in Bologna. In 1647, Grimaldi received a Ph.D., and in 1651 he received the priesthood.

Grimaldi came to the questions of optics from astronomy, which he studied under the influence of the famous Italian astronomer J. Riccioli. Grimaldi assisted him in preparing for the publication of the book "New Almagest".

The main scientific work of F. Grimaldi, to which he dedicated the last years of his life, was published posthumously in 1665. The book, entitled "Physico-Mathematical Treatise on Light, Colors and Rainbows," begins with a statement about the discovery of diffraction - the deflection of light, the violation of the straightness of its propagation when interacting with an obstacle, for example, when passing through small holes. The term "diffraction" was introduced by Grimaldi himself and is used to this day. The phenomenon of diffraction was discovered by Grimaldi during experiments with narrow beams of rays. The scheme of one of the experiments is shown in Fig.7.

Fig. 7. Scheme of Grimaldi's experiment on diffraction

A beam of rays passes through the slit CD in the plate AB - sunlight. In the path of the beams that have passed through the slit CD, there is another slit GH in the plate EF. It turned out that the rays passing through GH form a cone, the base of which IK is noticeably larger than it should follow from the geometric constructions (NDM and LCO cones). In addition, the edges of the light spots observed on the screen turned out to be colored, according to Grimaldi's description, in red and bluish colors, while the central spot was white, "flooded with pure light." Grimaldi explains this phenomenon by the formation of waves in the light fluid behind the obstacle, which deviate behind the hole.

For a long time the question of the speed of light remained open. A remarkable event in the study of this issue was the discussion between R. Descartes and P. Fermat, which led Fermat to formulate the principle of "least time" for the propagation of light. Fermat was of the opinion that the propagation of light was instantaneous, but he was looking for a grain of truth in the metaphysical statement, known since antiquity, that nature always acts along the shortest path. But what is the shortest path? As it turned out, this is not the closest, not the easiest, not the path with the least resistance, but the path with the shortest time. This principle is known as Fermat's principle. Having accepted the hypothesis of the finiteness of the speed of light and its dependence on the properties of the medium, combining this hypothesis with the principle of the shortest time, Fermat obtained, to his surprise, the law of refraction, which coincided with the law of Descartes. Fermat also gave an inverse formulation of this law, according to which if the refraction obeys the law of Descartes, and if the refractive index is equal to the ratio speeds of light in the first and second medium, then the light, when propagating from one medium to another, follows the path at which the propagation time is the smallest.

The name of Pierre Fermat (1601-1665) is also known in connection with his theorem, which has not yet been proved. By profession, Fermat was a lawyer, worked as a lawyer in Toulouse, an adviser to the parliament, and mathematics was a desirable hobby for him. He liked to read the writings of ancient scholars. In the margins of "Arithmetic" by Diophantus of Alexandria, Fermat wrote that it was impossible to solve the equation

where n is an integer greater than 2. Fermat writes: "I found an amazing proof of this conjecture, but there is too little space to fit it." Despite the efforts eminent mathematicians, a proof of Fermat's assertion general view not found, but obtained only for some special cases.

Let's return to the problem of the speed of light. Using the experimental technique of that time, measuring the speed of light was impossible. Therefore, it was natural to use astronomical observations, that is, observations at distances at which the propagation time of light becomes available for measurement. The proof of the finiteness of the speed of light belongs to the Danish scientist Olaf Roemer.

Remer was born in Aarguz in the family of a merchant. He studied at the University of Copenhagen, studied medicine, physics, astronomy. In 1671 Roemer accepted an invitation to work at the Paris Observatory. In Paris, he takes an active part in solving a number of technical problems in making the most accurate astronomical observations. It is interesting to note that he taught mathematics to the heir to the French throne. It was here, in Paris, that Roemer proved the finiteness of the speed of light while observing one of Jupiter's moons. The scheme of observations is shown in Fig. 8.

Fig. 8. Scheme of Roemer's observations of Jupiter's satellite

Let A be the Sun, B be Jupiter, D and C be the positions of Jupiter's satellite Io, entering the shadow at point C and leaving the shadow at point D; K, L, G, F are observation points from the Earth's orbit, EH is the diameter of the Earth's orbit passing through the Sun. When the Earth moves away from the orbit of Jupiter, moving from point L to point K, the moment of exit from the satellite’s shadow at point D will be delayed by the time of radiation propagation from point L to point K. And, on the contrary, when moving from point F to point G, the moment of exit from the shadow will be close to the same interval. According to Roemer's calculations, it takes 22 minutes to pass the EH interval equal to the diameter of the Earth's orbit ( contemporary meaning 16 min. 36 sec.).

Roemer presented his theory to the Paris Academy of Sciences, but this theory met in an academic environment dominated by Cartesianism, strong resistance. Most of the prominent scientists of that time, including I. Newton, H. Huygens, G.V. Leibniz shared Roemer's views.

After returning to his homeland, Remer created a first-class observatory, improved a number of astronomical instruments that equipped the laboratory. At the end of his life, Remer devoted a lot of time and energy to state affairs, being the head of the State Council.

An outstanding contribution to the development of theoretical optics, to the theory of light was made by the Dutch scientist Christian Huygens, whose name is immortalized by the name of one of the fundamental principles of optical theory - the "Huygens principle".

H. Huygens was born in The Hague into a noble and wealthy family. Mathematics and physics fascinated Christian from childhood, but he received a law degree at Leiden and Breda universities. Huygens apparently studied mathematics on his own. His mentor in this matter was the famous Dutch mathematician of that time, Van Schoten. In 1651, when Huygens was only 22 years old, he wrote his first treatise on mathematics, "Theorems on the quadrature of the hyperbola of an ellipse and a circle and the center of gravity of their parts."

After graduating from the university, Huygens is engaged in diplomatic work, then travels to France, enters the Protestant University of Angers, receives a doctorate in law. But returning to Holland, he ceases to practice law and devotes himself entirely to astronomy, mechanics, mathematics and optics.

Written by him in 1657. the treatise “On Calculations in Gambling” became one of the first works on the emerging theory of probability.

Throughout his life, Huygens was engaged in the manufacture of optical systems. Passion for polishing glass came to him in his youth. Huygens invented the lens grinding machine and created spotting scopes good quality, which allowed him to open the “ring of Saturn”. In his telescopes, which had a high magnification, Huygens applied the scheme of the eyepiece, which now bears his name - the “Huygens eyepiece”. To announce his discovery of the ring, or, as he believed, the satellite (“moon”) of Saturn, Huygens, according to the then custom, sent a riddle (anagram) to famous astronomers, composed of letters that formed the following phrase: Saturno luna circumducitur diebus sexdecim, horas quatuor, that is: "Saturn is accompanied by the moon, which revolves around him in sixteen days and four hours." He carved on the lens of his spyglass this riddle and the words that served as its solution.

In addition to the ring of Saturn, Huygens discovered “caps” on Mars, nebulae in the constellation of Orion, and stripes on Jupiter. Astronomical observations required precise instruments to measure time. Nice watch the Dutch sailors also needed them. Huygens, in connection with this, invents a clock with a pendulum (patent from 1657). The idea of ​​a clock with a pendulum belongs, as we have already mentioned, to Galileo, but Huygens managed to realize it. Historians believe that Huygens arrived at his invention independently of Galileo. In the treatise "Pendulum Clock" (1658), Huygens outlined the theory of mathematical and physical pendulums, gave a formula for calculating the period of oscillation of a pendulum.

Huygens' astronomical research and the invention of the pendulum clock made his name known throughout Europe. In 1663 Huygens was elected the first foreign member of the Royal Society of London, and in 1665. he is invited to Paris as an honorary member of the French Academy of Sciences. Huygens stayed in Paris for 16 years (1665-1681). France became his second home. Here he establishes international scientific contacts, maintains contacts with Boyle, Hooke, Newton, Leibniz.

In connection with the hostile actions of Catholics against Protestants that began in France (Huygens was a Protestant), he leaves for his homeland, despite the persuasion Louis XIV stay. Huygens considered himself in science the successor of Galileo and Torricelli, whose theories he, in his own words, "confirmed and generalized."

Huygens' masterpiece in the field of mechanics is his work “Swinging clocks, or on the movement of a pendulum”. This work, published in 1673, provides a description of a pendulum clock, the movement of bodies along a cycloid, a development and determination of the lengths of curved lines, a determination of the center of oscillation, a description of the device of a clock with a circular pendulum, and a statement of the centrifugal force theorem.

Since 1659 Huygens worked on the treatise On Centrifugal Force, published posthumously in 1703. In it, Huygens laid out the laws governing centrifugal force. The idea of ​​centrifugal force was first clearly expressed by Huygens in his letter to the Secretary of the Royal Society of London dated September 4, 1669. This idea was coded as an anagram.

The derivation of the formula for centrifugal force was of great importance in the development of mechanics. When Newton was asked what to read in order to understand his work, he first of all pointed to the writings of Huygens.

Great importance in the development of dynamics has Huygens's work "On the motion of bodies under the influence of impact", completed in 1656, but published in 1700. Huygens considers the problem of elastic collision of bodies on the basis of three principles - the principle of inertia, the principle of relativity and the principle of conservation of the sum of the products of each "body" per the square of its speed before and after the impact - this value Leibniz called "live force" and opposed to "dead force", or potential energy. "Living force", as we now know, reflects kinetic energy, the formula for the calculation of which was obtained by Gustav Coriolis (1792-1843). Coriolis formula which differs from Huygens and Leibniz's "manpower" formula by a factor?.

Beginning around 1675. Huygens is entirely occupied with the problems of optics. His work in this area is summarized in the "Treatise on Light", published in Leiden (1690). In it, he first outlined a harmonious wave theory of light. The treatise consists of 6 chapters, in which the straightness of light propagation, reflection, refraction, atmospheric refraction, birefringence and, finally, the shape of lenses are considered in succession. Criticizing the positions of the supporters of the corpuscular theory (in particular, the impossibility of explaining with the help of this theory why intersecting beams of rays do not interact if they consist of separate particles), Huygens comes to the conclusion: “There is no doubt that light consists in the movement of some substance” . Huygens, taking the existence of this hypothetical substance as an axiom, considers the mechanism of light propagation.

Huygens put forward the principle of wave propagation of light, which consists in the fact that each point of the medium of light propagation, to which the perturbation has reached, itself becomes a source of secondary waves. This principle, bearing the name of Huygens, is considered by him on the example of a candle flame (Fig. 9).

Fig. 9. Huygens principle on the example of a candle flame

Points A, B, C of the flame communicate movement to the environment - the ether, that is, they create a wave. In turn, each point of the ether, as soon as it finds a perturbation, itself becomes the center of a new wave. Thus, wave motion propagates from point to point. The surface tangent to all secondary waves is a wave surface - a wave front. The principle of wavefront formation proposed by Huygens made it possible to brilliantly explain the laws of reflection and refraction, while Huygens' principle leads to Fermat's principle, but Huygens' proof is much simpler.

The weak point of Huygens' theory of light propagation was the not entirely satisfactory explanation of the straightness of light propagation. Huygens makes this explanation by analogy with an elastic impact on a group of balls. He writes: “If you take a huge number of balls of the same size from very solid, arrange them in a straight line so that they are in contact with each other, then whenever such a ball hits the first of them, the movement will spread in an instant to the next ball, which will separate from the row so that no one will notice how other balls also set in motion, and the one that made the blow will remain motionless ... Thus, a transmission of motion with an extraordinary speed is detected, which is the greater, the harder the substance of the balls. In order for such a mechanism of transmission of perturbations in the ether to be realizable, the ether must be endowed with absolute hardness and at the same time the property of penetrating into all bodies.

When putting forward his principle, Huygens proceeded from an analogy with sound and considered the wave oscillations of the ether to be longitudinal, that is, coinciding in direction with the propagation of the wave. But if we accept the nature of the ether oscillation as longitudinal, then a number of effects arising in birefringent crystals cannot be explained. These effects were explained if we accept Hooke's hypothesis about the transverseness of light waves.

As we can see, mechanical concepts dominated the optics of the 17th century. Physicists of that time, as a rule, were both mechanics and opticians. This is especially characteristic of the work of Robert Hooke, the greatest English physicist.

Guk came from a clergy family. His father wanted to see Robert as a pastor, but already in early years Hooke discovered remarkable abilities in mathematics and mechanics and was sent to study with a watchmaker, and then in Oxford University. At the age of 24 he worked as an assistant to Boyle, and in 1662. Hooke is invited to the post of "curator of experiments" in the Royal Society. Soon Hooke became a member of the Royal Society, and in 1667. - his secretary.

The London Royal Scientific Society of that time discussed not only theoretical, but also purely practical issues. So, for example, March 18, 1663. The society approved a proposal to breed potatoes in England in order to "prevent the possibility of famine in the future." Potato tubers were given to members of the society for breeding, and Guk also received several potatoes.

After a severe fire that occurred in London in 1666, the Royal Society was instructed to develop a plan for a new building. Hooke also presented his plan, but it was not accepted, although it was Hooke who became the building inspector. London was restored according to the plan of the remarkable architect Wren, the creator of the famous Peter and Paul Cathedral in London. The position of building inspector for London apparently brought considerable income. After Hooke's death in 1670. an iron box containing several thousand pounds sterling was found in his office.

Hook left invaluable scientific heritage. Hooke's name is associated with a fundamental law that establishes the relationship between mechanical stresses in an elastic body and the deformations they cause. Hooke published this law in 1678. in the form of an anagram of 14 letters, which can be translated as follows: "What is the force - such is the stretching." Hooke's law is fundamental in the sciences of the strength of materials.

Hooke improved many measuring instruments: an air pump (together with Boyle), a barometer with a circular scale, an anemometer (a device for measuring wind force) and many others.

In the field of optics Hooke's improvement of the microscope is of outstanding importance. The invention of the microscope is attributed to the Dutch spectacle maker Zachary Jansen. However, for scientific research The microscope was first used by Hooke. The device of the microscope is described by him in the book “Micrography” (1665). With the help of a microscope, Hooke saw the cells of the tissues of organisms. The very word "cell" was introduced by Hooke. The significance of Hooke's "Micrography" goes far beyond the problems associated with the microscope. Hooke sets out in this book, which has gained particular fame, his ideas about the nature of light, experiments to determine the elasticity of air, astronomical observations, observations of thin layers (soap bubbles, oil films, etc.) placed in a light beam.

Hooke came close to discovering the law of universal gravitation. In 1674 In his work “An Attempt to Prove the Movement of the Earth by Observations”, Hooke put forward three major assumptions, the essence of which is as follows.

First, there is an attractive force that all celestial bodies have, and this force is directed towards the center of the body.

Secondly, Hooke follows Galileo on the issue of the law of inertia.

Thirdly, the forces of attraction, according to Hooke, increase as you approach the attracting body.

In 1679 Hooke pointed out that if the attraction is inversely proportional to the square of the distance, then the shape of the orbit of the planets is an ellipse. Hooke made this assumption in his letter to Newton in Cambridge and offered it for discussion.

In a response letter, Newton expressed regret that at his age (Newton was then 37 years old) it was difficult to do mathematics and he was more interested in medieval alchemical recipes for making gold. As it turned out later, Newton was then already close to discovering the law of universal gravitation, or even discovered it, but was in no hurry to publish.

Biographers note the quarrelsome nature of R. Hooke, his attacks on the scientific priorities of H. Huygens, F. Grimaldi, I. Newton. But until his death, Hooke enjoyed the deepest respect of scientists in England and throughout Europe.

Dutch physicist, mechanic, mathematician and astronomer.

"The Greatest Mathematical Discovery Huygens- equation of pendulum oscillations. It was the first differential equation in the history of mathematics and the first equation in mechanics, the solutions of which turned out to be trigonometric functions.
On the basis of the resulting equation, Huygens built an accurate clock with a pendulum and proved that the period of oscillation of the pendulum depends only on its length and on the free fall acceleration g at a given point - on Earth or on another planet.
This property in the 17th century allowed physicists to experimentally find out the deviation of the shape of the Earth from the sphere, and later it was used in the exploration of metal ores (they have an increased density, therefore, the acceleration of free fall increases near the deposit).

Smirnov S.G., Task book on the history of science. From Thales to Newton, M., "Miros", 2001, p. 280.

In 1657 Christian Huygens invented a pendulum clock with an escapement mechanism, thanks to which the oscillations of the pendulum did not fade. In the same year, he wrote a treatise: On the calculations in gambling / De ratiociniis in ludo aleae - one of the first works on the theory of probability. His design of the clock carried out the movement of the center of gravity of the pendulum along the cycloid - so that the time of its swing Not depended on the range.

Biography

Together with his brother, he improved the telescope, bringing it to 92x magnification, and began to study the sky. The first fame came to Huygens when he discovered the rings of Saturn (Galileo also saw them, but could not understand what they were) and the satellite of this planet, Titan.

Mathematics and mechanics

Christian Huygens began his scientific activity in 1651 with an essay on the quadrature of the hyperbola, ellipse and circle. In 1654 he discovered the theory of evolute and involute.

In the first part of the work, Huygens describes an improved, cycloidal pendulum that has a constant swing time regardless of amplitude. To explain this property, the author devotes the second part of the book to the conclusion general laws motion of bodies in a gravitational field - free, moving along an inclined plane, rolling down a cycloid. It must be said that this improvement has not found practical application, since with small fluctuations the increase in accuracy from the cycloidal weight gain is insignificant. However, the research methodology itself entered the gold fund of science.

The fourth part presents the theory of the physical pendulum; here Huygens solves the problem that was not given to so many contemporary geometers - the problem of determining the center of oscillations. It is based on the following proposition:

If a complex pendulum, having left rest, has completed a certain part of its swing, more than a half-swing, and if the connection between all its particles is destroyed, then each of these particles will rise to such a height that their common center of gravity will be at that height, at which he was at the exit of the pendulum from rest.

This proposition, not proved by Huygens, appears to him as a basic principle, while now it is a simple consequence of the law of conservation of energy.

The theory of the physical pendulum was given by Huygens in quite a general form and applied to bodies of various kinds. Huygens corrected Galileo's mistake and showed that the isochronism of the pendulum oscillations proclaimed by the latter takes place only approximately. He also noted two more errors of Galileo in kinematics: uniform motion in a circle is associated with acceleration (Galileo denied this), and centrifugal force is proportional not to speed, but to the square of speed.

In the last, fifth part of his work, Huygens gives thirteen theorems on centrifugal force. This chapter gives for the first time an exact quantitative expression for the centrifugal force, which subsequently played important role to investigate the motion of the planets and discover the law of universal gravitation. Huygens gives in it (verbally) several fundamental formulas:

In 1657 Huygens wrote an appendix " About gambling settlements” to the book of his teacher van Schooten “Mathematical Etudes”. It was a meaningful exposition of the beginnings of the then emerging theory of probability. Huygens, along with Fermat and Pascal, laid its foundations. According to this book, Jacob Bernoulli got acquainted with the theory of probability, which completed the creation of the foundations of the theory.

Astronomy

Huygens improved the telescope on his own; in 1655 he discovered Saturn's moon Titan and described Saturn's rings. In the th he described the entire system of Saturn in a work he published.

He also discovered the Orion Nebula and other nebulae, observed binary stars, estimated (quite accurately) the period of rotation of Mars around its axis.

Optics and wave theory

Banknote of 25 guilders with a portrait of Huygens, 1950s, Netherlands

• Huygens participated in contemporaneous disputes about the nature of light. In 1678 he published A Treatise on Light, an outline of the wave theory of light. Another remarkable work he published in 1690; there he presented the qualitative theory of reflection, refraction and double refraction in Icelandic spar in the same form as it is now presented in physics textbooks. Formulated the so-called. Huygens' principle, which makes it possible to investigate the motion of the wave front, subsequently developed by Fresnel and which played an important role in the wave theory of light, and the theory of diffraction.

• He owns the original improvement of the telescope used by him in astronomical observations and mentioned in the paragraph on astronomy. He is also the inventor of the diascopic projector - the so-called. "magic lantern"

Other achievements

Pocket mechanical watch

• The theoretical discovery of the oblateness of the Earth at the poles, as well as an explanation of the influence of centrifugal force on the direction of gravity and on the length of the second pendulum at different latitudes.
• Solution of the question of the collision of elastic bodies, simultaneously with Wallis and Wren.
• One of the solutions to the question of the form of a heavy homogeneous chain in equilibrium: (chain line).
• The invention of the clock spiral, replacing the pendulum, is extremely important for navigation; The first clock with a spiral was designed in Paris by the watchmaker Thuret in 1674.
• In 1675 he patented a pocket watch.
• The first called for choosing a universal natural measure of length, which he proposed as 1/3 of the length of the pendulum with a period of oscillation of 1 second (this is about 8 cm).

Major writings

• Horologium oscillatorium, 1673 (Pendulum clock, in Latin).
• Kosmotheeoros. ( English translation edition of 1698) - Huygens' astronomical discoveries, hypotheses about other planets.
• Treatise on Light (Treatise on Light, English translation).

Notes

Literature

Huygens' works in Russian translation

• Archimedes. Huygens. Legendre. Lambert. About squaring the circle. With an appendix of the history of the question, compiled by F. Rudio. Per. S.N. Bernstein. Odessa, Mathesis, 1913. (Reprint: M.: URSS, 2002)
• Huygens H. Three treatises on mechanics. M.: Ed. Academy of Sciences of the USSR, 1951.
• Huygens H. A treatise on light, which explains the reasons for what happens to it during reflection and refraction, in particular during the strange refraction of the Icelandic crystal. M.–L.: ONTI, 1935.

Literature about him

• Veselovsky I.N. Huygens. Moscow: Uchpedgiz, 1959.
• History of mathematics, edited by A. P. Yushkevich in three volumes, M .: Nauka, Volume 2. Mathematics of the 17th century. (1970)
• Gindikin S.G. Stories about physicists and mathematicians. M: MTsNMO, 2001.
• Costabel P. The invention of the cycloidal pendulum by Christian Huygens and the craft of a mathematician. Historical and mathematical research, issue. 21, 1976, p. 143–149.
• Mah E. Mechanics. Historical and critical sketch of its development. Izhevsk: RHD, 2000.
• Frankfurt U.I., Frank A.M. Christian Huygens. Moscow: Nauka, 1962.
• John J. O'Connor and Edmund F. Robertson. Huygens, Christian in the MacTutor archive

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Huygens: Constantine Huygens (September 4, 1596 - March 28, 1687) was a Dutch poet, scholar and composer. Father of Christian Huygens. Christian Huygens (April 14, 1629 - July 8, 1695) Dutch mathematician, physicist and astronomer. Son of Constantine ... ... Wikipedia

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Huygens- Huygens, a: the principle of Huygens (or Huygens Fresnel) ... Russian spelling dictionary

Huygens- a nickname * A woman is a nickname of the same type, like in one, so in a plurality they do not change ... Spelling Dictionary of Ukrainian Movies

Huygens H.- HUYGENS, Huygens Christian (162995), Netherlands. naturalist. In 166581 he worked in Paris. Invented (1657) a pendulum clock with an escapement, gave their theory, established the laws of physical oscillations. pendulum, laid the foundations ... ... Biographical Dictionary

The Dutch physicist, mechanic, mathematician and astronomer, Christian Huygens, was Galileo's immediate successor in science. Lagrange said that Huygens "was destined to improve and develop the most important discoveries of Galileo." Huygens first came into contact with Galileo's ideas at the age of 17: he was going to prove that bodies thrown horizontally move along a parabola, and found such a proof in Galileo's book.

Huygens' father came from a Dutch noble family and received an excellent education: he knew the languages ​​and literature of many peoples and eras, he himself wrote poetic works in Latin and Dutch. He was also a connoisseur of music and painting, a subtle and witty person. He was interested in the achievements of science in the field of mathematics, mechanics and optics. The originality of his personality is confirmed by the fact that among his friends there were many famous people, including the famous Rene Descartes, an outstanding French scientist.

The influence of Descartes was strongly reflected in the formation of the worldview of his son, the future great scientist.

Childhood and youth.

At the age of eight, Christian learned Latin, knew the four steps of arithmetic, and at the age of nine he became acquainted with geography and the beginnings of astronomy, knew how to determine the time of sunrise and sunset in all seasons. When Christian was ten years old, he learned to compose verses in Latin and play the violin, at eleven he got acquainted with playing the lute, and at twelve he knew the basic rules of logic.

After studying Greek, French and Italian, as well as playing the harpsichord, Christian moved on to the mechanics, which captured him entirely. He designs various machines, for example, he makes his own lathe. In 1643, Christian's teacher tells his father: "Christian must be called a miracle among boys ... He develops his abilities in the field of mechanics and structures, makes amazing machines ...".

Further, Christian learns mathematics, horseback riding and dancing. A handwritten mathematical course for Christian, compiled by the famous mathematician, friend of Descartes, Francis Schouten, has been preserved. The course covered the principles of algebra and geometry, indefinite equations from Diophantus' Arithmetic, irrational numbers, extraction of square and cube roots, and the theory of algebraic equations of higher degrees. Rewritten book of Descartes "Geometry". Then applications of algebra to geometry and equations of locus are given. Finally, conic sections are considered and problems are given for constructing tangents to various curves by the methods of Descartes and Fermat.

At the age of sixteen, Christian, together with his brother, entered the University of Leiden to study law and at the same time studied mathematics with Schouten, who sent Descartes his first mathematical work for review. Descartes praises Christian's "mathematical inventions": "Although he did not quite get what he needed, this is by no means strange, since he tried to find things that no one else had succeeded in. He took up this matter in such a way that I am sure that he will become an outstanding scientist in this field.

At this time, Christian studied Archimedes, Apollonius' "Conic Sections", Vitello and Kepler's optics, Descartes' "Dioptrics", Ptolemy's and Copernicus' astronomy, and Stevin's mechanics. Getting acquainted with the latter, Huygens proves that the statement that the equilibrium figure of a thread freely suspended between two points is a parabola is false. At present, it is known that the thread will be located along the so-called catenary.

Christian corresponded with Marin Mersenne, a Franciscan friar, publisher of the French translation of Galileo's Mechanics and summary his "Dialogues ...". Mersenne was keenly interested in the scientific achievements of his time and in letters reported on latest discoveries and the most interesting problems of mathematics and mechanics. In those days, such correspondence replaced the missing scientific journals.

Mersenne sent Christian interesting tasks. From his letters, he got acquainted with the cycloid and the center of swing of the physical pendulum. Upon learning of Huygens's criticism of the parabolic form of the filament, Mersenne reported that the same mistake had been made by Galileo himself, and asked to be sent the full proof.

Finishing his report to Mersenne on his work, he wrote: “I decided to try to prove that heavy bodies thrown up or to the side describe a parabola, but in the meantime I came across Galileo's book on accelerated natural or violent motion; when I saw that he had proved this and much more, I no longer wanted to write the Iliad after Homer.

Huygens and Archimedes.

After Leiden, Christian with his younger brother Lodevik goes to study at the Orange Collegium. The father, apparently, was preparing Christian for state activity, but this did not tempt Christian.

In the spirit of Archimedes, the twenty-three-year-old Christian wrote a book on the theory of floating bodies: "On the equilibrium of bodies floating in a liquid." Later, in 1654, another work appeared in the spirit of Archimedes, Discoveries on the Size of the Circle, which represented an advance on Archimedes's Measuring the Circle. Huygens obtained the value of pi with eight correct decimal places. This also includes the work "Theorems on the quadrature of the hyperbola, ellipse and circle and the center of gravity of their parts."

Written in 1657, the treatise "On Calculations in Gambling" is one of the first famous works according to the theory of probability.

Huygens and optics.

As early as 1652, Huygens became interested in the theme developed by Descartes. It was dioptrics - the doctrine of the refraction of light. He writes to his friend: “I have almost written two books on this subject, to which a third is added: the first speaks of refraction in flat and spherical surfaces ..., the second is about a visible increase or decrease in the images of objects obtained by refraction. The third book, which was supposed to talk about telescopes and microscopes, was written a little later. Huygens worked intermittently on the Dioptric for about 40 years (from 1652 to 1692).

Separate chapters of the first part of "Dioptrics" are devoted to the refraction of light in flat and spherical surfaces; the author gives experimental definition refractive index of different transparent bodies and considers the problems of light refraction in prisms and lenses. Then he determines the focal length of the lenses and investigates the relationship between the position of the object on the optical axis of the lens and the position of its image, that is, he obtains the expression of the main formula of the lens. The first part of the book ends with a consideration of the structure of the eye and the theory of vision.

In the second part of the book, Huygens talks about the reversibility of an optical system.

In the third part of the book, the author gives great attention spherical aberration (distortion) of lenses and methods for its correction. For a number of special cases, he finds the shape of the refractive surfaces of lenses that do not give spherical aberration. In order to reduce the aberrations of the telescope, Christian proposes an "air telescope" design, where the lens and eyepiece are not connected. The length of Huygens' "air telescope" was 64 m. With the help of this telescope, he discovered a satellite of Saturn, Titan, and also observed four satellites of Jupiter, previously discovered by Galileo.

Huygens, with the help of his telescopes, was also able to explain the strange appearance of Saturn, which confused astronomers, starting with Galileo - he established that the body of the planet is surrounded by a ring.

In 1662 Huygens also proposed a new optical system eyepiece, which was later named after him. This eyepiece consisted of two positive lenses separated by a large air gap. Such an eyepiece according to the Huygens scheme is widely used by opticians today.

In 1672-1673 Huygens got acquainted with Newton's hypothesis about the composition white light. Around the same time, he formed the idea of ​​a wave theory of light, which finds expression in the famous "Treatise on Light", published in 1690.

Huygens and mechanics.

Huygens should be placed at the very beginning of a long line of researchers who took part in the establishment of the universal law of conservation of energy.

Huygens proposes a method for determining the velocities of bodies after their collision. The main text of his treatise "The Theory of the Impact of Solids" was completed in 1652, but Huygens's characteristic critical attitude towards his works led to the fact that the treatise was published only after Huygens' death. True, while in England in 1661, he demonstrated experiments confirming his theory of impact. The secretary of the Royal Society of London wrote: “A ball weighing one pound was suspended in the form of a pendulum; when he was released, he was hit by another ball, suspended in the same way, but only weighing half a pound; the deflection angle was forty degrees, and Huygens, after a little algebraic calculation, predicted what the result would be, which turned out to be exactly as predicted.

Huygens and clock.

The period from December 1655 to October 1660 is the time of the greatest flowering scientific activity Huygens. At this time, in addition to completing the theory of the ring of Saturn and the theory of impact, almost all of the main works of Huygens, which brought him fame, were completed.

Huygens in many respects inherited and improved on the solution of problems undertaken by Galileo. For example, he turned to the study of the isochronous nature of the oscillations mathematical pendulum(property of oscillations, manifested in the fact that the frequency of small oscillations practically does not depend on their amplitude). Probably, at one time this was Galileo's first discovery in mechanics. Huygens had the opportunity to supplement Galileo: the isochronism of a mathematical pendulum (that is, the independence of the period of oscillation of a pendulum of a certain length on the amplitude of the swing) turned out to be valid only approximately, and even then for small angles of deflection of the pendulum. And Huygens realized the idea that occupied Galileo in his last years of life: he designed a pendulum clock.

The task of creating and improving clocks, especially pendulum clocks, Huygens was engaged in for almost forty years: from 1656 to 1693.

One of the main memoirs of Huygens, devoted to the consideration of results in mathematics and mechanics, was published in 1673 under the title "Pendulum Clocks or Geometric Proofs Relating to the Movement of Pendulums Fitted to Clocks". Trying to solve one of the main problems of his life - to create a clock that could be used as a marine chronometer, Huygens came up with many solutions and thought through many problems, exploring the possibilities of their application to this problem: the cycloidal pendulum, the theory of sweeping curves, centrifugal forces and their role, etc. At the same time, he solved emerging mathematical and mechanical problems. Why did the task of creating watches so attracted the famous scientist?

Clocks are among the very ancient inventions of man. At first it was solar, water, hourglasses; In the Middle Ages, mechanical watches appeared. For a long time they were bulky. There were several ways to convert the accelerated fall of the load into a uniform movement of the hands, but even Tycho Brahe's astronomical clock, known for its accuracy, was “adjusted” forcibly every day.

It was Galileo who first discovered that the oscillations of the pendulum are isochronous and was going to use the pendulum to create clocks. In the summer of 1636, he wrote to the Dutch admiral L. Real about connecting a pendulum to an oscillation counter (this is essentially the pendulum clock project!). However, due to illness and imminent death, Galileo did not finish the work.

The difficult path from laboratory experiments to the creation of pendulum clocks was overcome in 1657 by Christian Huygens, already a well-known scientist at that time. On January 12, 1657, he wrote:

"These days I have found a new design of watches, with which time is measured so accurately that there is no small hope that it will be possible to measure longitude with it, even if they have to be transported by sea."

From that moment until 1693, he strived to improve the clock. And if at the beginning Huygens showed himself as an engineer, using the isochronous property of the pendulum in a known mechanism, then gradually his abilities as a physicist and mathematician were more and more manifested.

Among his engineering discoveries there were a number of truly outstanding ones. Huygens' clock was the first to implement the idea of ​​self-oscillations based on feedback: the energy was imparted to the pendulum in such a way that "the source of oscillations itself determined the moments of time when energy delivery was required." For Huygens, this role was played by a simple device in the form of an anchor with obliquely cut teeth, rhythmically pushing the pendulum.

Huygens discovered that the oscillations of the pendulum are isochronous only at small angles of deviation from the vertical, and decided to reduce the length of the pendulum with increasing angle of deviation in order to compensate for the deviations. Huygens figured out how to implement it technically.

Wave theory of light.

In the seventies, Huygens' main attention was drawn to light phenomena. In 1676, he came to Holland and met one of the creators of microscopy, Anthony van Leeuwenhoek, after which he tried to make a microscope himself.

In 1678 Huygens arrived in Paris, where his microscopes made a terrific impression. He demonstrated them at a meeting of the Paris Academy.

Christian Huygens became the creator of the wave theory of light, the main provisions of which were included in modern physics. He outlined his views in the Treatise on Light, published in 1690. Huygens believed that the corpuscular theory of light, or the theory of expiration, contradicts the properties of light rays not to interfere with each other when crossing. He believed that the universe is filled with the thinnest, and in the highest degree, a moving elastic medium - the world ether. If a particle begins to oscillate in any place of the ether, then the oscillation is transmitted to all neighboring particles, and an ethereal wave runs through space from the first particle as the center.

Wave concepts allowed Huygens to theoretically formulate the laws of reflection and refraction of light. He gave a visual model of the propagation of light in crystals.

The wave theory explained the phenomena of geometric optics, but since Huygens compared light waves and sound waves and believed that they are longitudinal and propagate in the form of impulses, he could not explain the phenomena of interference and diffraction of light, which depend on the periodicity of light waves. In general, Huygens was much more interested in waves as the propagation of oscillations in a transparent medium than in the mechanism of the oscillations themselves, which was not clear to him.

Stories about scientists in physics. 2014