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BIOGRAPHIES OF GREAT SCIENTISTS
Pendant Charles Augustin. Biography of a scientist
Directory / Biographies of great scientists
French physicist and engineer Charles Coulomb achieved brilliant scientific results. The laws of external friction, the law of torsion of elastic threads, the basic law of electrostatics, the law of the interaction of magnetic poles - all this entered the golden fund of science. "Coulomb field", "Coulomb potential", and finally, the name of the unit of electric charge "coulomb" is firmly entrenched in physical terminology. Charles Augustin Coulomb was born on June 14, 1736 in Angouleme, which is located in the southwest of France. His father, Henri Coulomb, who at one time tried to make a military career, had become a government official by the time his son was born. Angouleme was not the permanent residence of the Coulomb family; some time after the birth of Charles, she moved to Paris. Charles's mother, nee Catherine Bage, who came from a noble family de Senac, wanted her son to become a doctor. Based on this idea, she chose an educational institution that Charles Augustin initially attended - the College of the Four Nations, also known as the Mazarin College. The further fate of Coulomb was determined by the events that took place in the life of his family. Henri Coulomb, who apparently did not have serious abilities in the financial field, went bankrupt, embarking on speculation, as a result of which he was forced to leave Paris for his homeland, in Montpellier, in the south of France. Many influential relatives lived there, who could help the unsuccessful financier. His wife did not want to follow her husband and remained in Paris with Charles and his younger sisters. However, the young Coulomb did not live long with his mother. His interest in mathematics grew so much that he announced his decision to become a scientist. The conflict between mother and son led to the fact that Charles left the capital and moved to his father in Montpellier. Louis' father's cousin, who held a prominent position in Montpellier, knew many of the members of the city's Royal Society of Science. Soon he introduced his nephew Charles to society. In February 1757, at a meeting of the Royal Scientific Society, a young lover of mathematics read his first scientific work, "A Geometric Sketch of Mean Proportional Curves." Since the work earned the approval of members of the society, the novice researcher was soon elected an adjunct in the mathematics class. Subsequently, Coulomb took an active part in the work of the society and presented five more memoirs - two in mathematics and three in astronomy. His interest in astronomy was sparked by observations he made with another member of the Montpellier Society, de Ratt. Charles participated in observations of a comet and a lunar eclipse, the results of which he presented in the form of memoirs. Coulomb was also interested in the theoretical issues of astronomy: one of his works was devoted to determining the meridian line. In February 1760, Charles entered the Mézières School of Military Engineers. Luckily for him, a teacher of mathematics, Abbé Charles Bossu, who later became a famous scientist, worked at the school. Having become close to Bossu during his studies at Mézières on the basis of his interest in mathematics, Coulomb maintained friendly relations with him for many years. Another important source of knowledge that later came in handy for Coulomb in his scientific work were lectures on experimental physics, which in the summer of 1760 began to be read at school by the famous French naturalist Abbé Nollet. In November 1761, Charles graduated from the School and was assigned to a major port on the western coast of France - Brest. Then he came to Martinique. During the eight years spent there, he was seriously ill several times, but each time he returned to his official duties. These diseases did not go unnoticed. After returning to France, Coulomb could no longer feel completely healthy. Despite all these difficulties, Coulomb performed his duties very well. His success in building a fort at Mont Garnier was marked by a promotion: in March 1770 he received the rank of captain - at that time it could be considered a very quick promotion. Soon, Coulomb fell seriously ill again and, finally, filed a report with a request to be transferred to France. After returning to his homeland, Coulomb was assigned to Bushen. Here he completes a study begun during his service in the West Indies. Although Coulomb, with his characteristic modesty, referred himself to the "other workers", in fact, many of the ideas formulated by him in his first scientific work are still considered fundamental by specialists in the strength of materials. According to the tradition of that time, in the spring of 1773, Coulomb presented his memoir to the Paris Academy of Sciences. He read the memoir at two meetings of the academy in March and April 1773. The work was received with approval. Academician Bossu, in particular, wrote: “Under this modest title, Monsieur Coulomb embraced, so to speak, all architectural statics ... Throughout his study, we note a deep knowledge of infinitesimal analysis and wisdom in the choice of physical hypotheses, as well as in their application. Therefore, we We believe that this work fully deserves the approval of the Academy and is worthy of publication in the Collection [of Works] of Foreign Scientists." In 1774, Coulomb was transferred to the large port of Cherbourg. The pendant was happy with this appointment - he believed that it was in the port city that a military engineer could find the best use for his knowledge and abilities. In Cherbourg, where Coulomb served until 1777, he repaired a number of fortifications. This work left enough free time, and the young scientist continued his scientific research. The main topic that Coulomb was interested in at that time was the development of an optimal method for manufacturing magnetic needles for accurate measurements of the Earth's magnetic field. This topic was given in a competition announced by the Paris Academy of Sciences. Two winners of the competition in 1777 were announced at once - the Swedish scientist van Schwinden, who had already put forward the work for the competition, and Coulomb. However, for the history of science, it is not the chapter of Coulomb's memoir devoted to magnetic needles that is of greatest interest, but the next chapter, where the mechanical properties of the threads on which the arrows are hung are analyzed. The scientist conducted a series of experiments and established the general order of dependence of the moment of torsion deformation force on the angle of twist of the thread and on its parameters: length and diameter. The low elasticity of silk threads and hair with respect to torsion made it possible to neglect the arising moment of elastic forces and to assume that the magnetic needle exactly follows the declination variations. This circumstance served as an impetus for Coulomb to study the torsion of cylindrical metal threads. The results of his experiments were summarized in the work "Theoretical and experimental studies of the torsion force and elasticity of metal wires", completed in 1784. The picture of deformations drawn by Coulomb, of course, differs in many of its features from the modern one. However, the general cause of the occurrence of inelastic deformations - the complex dependence of the forces of intermolecular interaction on the distance between molecules - was correctly indicated by Coulomb. The depth of his ideas about the nature of deformations was noted by many scientists of the XNUMXth century, including such well-known ones as T. Jung. Gradually, Coulomb became more and more involved in scientific work, although it cannot be said that he was indifferent to his duties as a military engineer. In 1777, Coulomb was transferred again, now to the east of France in the small town of Salin. At the beginning of 1780 he was already in Lille. And everywhere Coulomb finds an opportunity for scientific research. Coulomb did not serve long in Lille. His dream came true - in the first half of September 1781, the Minister of War announced the transfer of Coulomb to Paris, where he was to deal with engineering issues related to the infamous Bastille prison fortress. On 30 September he was awarded the St. Louis Cross. His hopes associated with the Paris Academy of Sciences were also justified. On December 12, 1781, he was elected to the academy in the class of mechanics. Moving to the capital meant not only a change in the place of service and the range of duties. This event led to a qualitative change in the subject matter of Coulomb's scientific research. Coulomb conducted a series of experiments in which he studied the most important features of the friction phenomenon. First of all, he studied the dependence of the static friction force on the duration of contact between bodies. He found that in bodies of the same name, for example, "tree - tree", the duration of contact has little effect. When opposite bodies come into contact, the coefficient of static friction increases over several days. Coulomb also noted the so-called stagnation phenomenon: the force required to transfer bodies in contact from a state of rest to a state of relative motion is much greater than the force of sliding friction. With his experiments, Coulomb laid the foundations for studying the dependence of the sliding friction force on the relative speed of the bodies in contact. The special significance of Coulomb's work for practice lies in the fact that when conducting experiments, he used large loads close to those encountered in real life: their mass reached 1000 kg! This feature of Coulomb's research led to a long life of his results - the measurement data contained in the memoir "Theory of Simple Machines" were used by engineers for almost a century. In the field of theory, Coulomb's merit lies in the creation of a fairly complete mechanical picture of friction. He returned to research on this topic ten years later. In 1790, he submitted to the academy a memoir "On Friction at the Point of Support". In it, the scientist studied the friction that occurs during spinning and swinging. And in 1784, Coulomb took up the issue of internal friction in a liquid. The scientist managed to give his more complete solution many years later, in the work of 1800, which was called "Experiments on the determination of the cohesion of liquids and the law of their resistance at very slow motions." Especially carefully Coulomb explores the dependence of the resistance force on the speed of the body. In his experiments, the speed of the body varies from fractions of a millimeter to several centimeters per second. As a result, the scientist comes to the conclusion that at very low speeds the drag force is proportional to the speed, at high speeds it becomes proportional to the square of the speed. The study of the torsion of thin metal threads, carried out by Coulomb for the competition of 1777, had an important practical consequence - the creation of a torsion balance. This instrument could be used to measure small forces of various natures, and it provided a sensitivity unprecedented in the XNUMXth century. Having developed the most accurate physical device, Coulomb began to look for a worthy application for it. The scientist begins work on the problems of electricity and magnetism. His seven memoirs represent the implementation of a research program rare in the XNUMXth century in breadth. The most important result obtained by Coulomb in the field of electricity was the establishment of the basic law of electrostatics - the law of interaction of motionless point charges. The experimental substantiation of the famous "Coulomb's law" is the content of the first and second memoirs. There, the scientist formulates the fundamental law of electricity: "The repulsive force of two small balls, electrified by electricity of the same nature, is inversely proportional to the square of the distance between the centers of the balls." In the third memoir, Coulomb drew attention to the phenomenon of electric charge leakage. The main result was the establishment of an exponential law of decreasing charge with time. In the next, one of the shortest memoirs of the series, Coulomb addressed the question of the nature of the distribution of electricity between bodies. He proved that "electric fluid is distributed in all bodies in accordance with their form." The fifth and sixth memoirs are devoted to a quantitative analysis of the charge distribution between contiguous conducting bodies and to the determination of the charge density in various parts of the surface of these bodies. With regard to magnetism, Coulomb tried to solve the same problems as for electricity. The description of experiments with permanent magnets is an essential part of the second memoir and practically the entire seventh memoir of the series. The scientist managed to catch some peculiar features of magnetism. On the whole, however, the generality of the results obtained by Coulomb in the field of magnetism is much less than the generality of the laws established for electricity. Thus, Coulomb laid the foundations of electro- and magnetostatics. He obtained experimental results of both fundamental and applied importance. For the history of physics, his experiments with torsion balances were of paramount importance also because they gave physicists a method for determining the unit of electric charge through the quantities used in mechanics: force and distance, which made it possible to conduct quantitative studies of electrical phenomena. Coulomb's last memoir in a series on electricity and magnetism was submitted to the Paris Academy of Sciences in 1789. In December 1790, Coulomb submitted his resignation. In April of the following year, his request was granted, and he began to receive a pension of 2240 livres a year, which, however, was significantly reduced a few years later. By the end of 1793, the political situation in Paris became even more aggravated. Therefore, Coulomb decided to move away from Paris. He moves with his family to his estate near Blois. Here the scientist spends almost a year and a half, fleeing political storms. Coulomb lived in the village until December 1795. The return to Paris took place after the election of Coulomb as a permanent member of the department of experimental physics of the Institute of France - a new national academy. When exactly Coulomb became a family man is unclear. It is only known that the wife of the scientist Louise Françoise, nee Desormo, was much younger than him. Officially, their marriage was registered only in 1802, although the first son of Coulomb, named after his father Charles Augustin, was born in 1790. The second son, Henri Louis, was born in 1797. He devotes the last years of his life to organizing a new education system in France. Traveling around the country finally undermined the health of the scientist. In the summer of 1806, he fell ill with a fever that his body could no longer cope with. Coulomb died in Paris on August 23, 1806. The scientist left a rather significant legacy to his wife and sons. As a sign of respect for the memory of Coulomb, both of his sons were assigned to privileged educational institutions at public expense. Author: Samin D.K.
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