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GIANTS OF HUMAN CIVILIZATION 5

Dr sci. SIMO JELAČA

GOTTFRIED LEIBNIZ (1646-1716), German mathematician

Leibniz is remembered as a very persistent researcher in the development of mathematical theories, primarily statistics. In London he met with Newton, and later both claimed to be the first to find the bill, which has never been fully confirmed. Leibniz could be trusted more if he was right. In 1700, Leibniz convinced Frederick I of Prussia to form the Prussian Academy of Sciences, of which Leibniz became the first president.

EDMUND HALLEY (1656-1742), English astronomer

Halley most often mentions the comet he discovered in 1682 and which was named after him, Halley's Comet. Halley encouraged Newton to publish his Principles. He studied the occurrences and trajectories of comets in space and concluded that comets reappear at a precisely determined time period. According to his calculations, Halley's Comet appears every 76 years, and indeed, it appeared again in 1758, then in 1834, then in 1910, and lastly in 1986, with the next appearance occurring in 2062. This means that Halley's Comet can only be seen once in a human lifetime. Halley studied the trajectories of twenty-three comets, which he published in 1705 in "A Synopsis of the Astronomy of Comets". He also established that the stars also have their paths, and for the Moon he calculated a nineteen-year path based on which he confirmed the theory of secular acceleration, which he predicted as early as 1695. In 1716, he calculated the Earth's distance from the Sun in relation to the planet Venus. He also made a map of the southern constellation in 1679

In addition to astronomy, Halley is considered the founder of geophysics, in 1686, by making maps of the winds on earth, with sea currents and magnetic vibrations. He also studied the salinity of the sea and the evaporation of lakes in 1687-1694, according to which he calculated the age of the Earth. He mathematically calculated pressures as a function of altitude, thus perfecting the barometer. He even calculated the mortality of the population, the size of the atom, the optics of the rainbow, etc.

THOMAS NEWCOMEN (1663-1729), English inventor

Newcomen started building the first steam engine in 1705, and put it into operation in 1712. He had his own workshop where he produced devices for pumping out water from mining wells. He first thought of using atmospheric pressure instead of horses and human labor, so he created a vacuum on one side and pressure on the other, which created a certain amount of work. Then, instead of air, he used water vapor in 1712 and thus successfully solved the given task. Using levers, his pump drew 27,000 liters of water per hour at a power of 5.5 HP. During his lifetime, he installed 29 such pumps. After him, a much better solution was achieved by James Watt (1736-1819), which started the industrial revolution.

DANIEL FAHRENHEIT (1686-1736), German physicist

Fahrenheit was born in Gdańsk, Poland and spent most of his life working in Italy, where he became interested in thermometry. The first primitive thermometer was constructed by Galileo, while Fahrenheit first used alcohol for his thermometers in 1709, then mercury in 1714. As early as 1715, he constructed a thermometer scale, accepting the freezing point of water as the zero point. Through his calculations, he discovered that water freezes at 30°F, and that the human body temperature is 90°F. Later these values ​​were revised to 32°F and 96°F respectively. According to that scale, the boiling point of water was at 212°F. According to the given scale from 32 to 212, there are 180 divisions and the same was used all over the world, until 1970 in England, and in the USA until today. Later, the Fahrenheit scale was largely replaced by the Celsius scale, according to the Swedish author Anders Celsius (1701-1744).

DANIEL BERNOULI (1700-1782), Swiss mathematician and physicist

After completing his studies in Europe, Bernoulli went to the Academy of Sciences in St. Petersburg, Russia, where he studied mathematics. At the age of 32, he went to Switzerland, where he worked as a professor of anatomy, then botany and finally physics. He is remembered for his work Hydrodynamics, in which in 1738 he described the properties of flowing water, which is known in science as Bernoulli's law and Bernoulli's formula.

CAROLUS LINNAEUS (1707-1778), Swedish botanist

Carolus Linus loved flowers from an early age, which is why he got the nickname "The Little Botanist". Already in 1735, he published his first work, Systema Naturae (Natural System), in which he established a new system of naming plants. Each name consists of two words, the first of which defines the genus or group of species to which the plant in question belongs, and the second word designates a specific species or type of plant. For example, the name of the sunflower is Helianthemum annus according to Linus. Linus's method was far simpler than any previous method. This system of naming plants is still in use today, all over the world.

RUĐER BOŠKOVIĆ (1711-1787), Dubrovnik scientist and diplomat

Ruđer Bošković was born in Ragusa (Dubrovnik), and studied mathematics and physics in Rome. He is one of the first world scientists to accept Isaac Newton's theory of universal gravitation. He worked in Rome for most of his life, but it was precisely because of Newton that he went to Britain in 1759, where he had the opportunity to meet many world scientists of that time. Bošković was well known to British scientists for his theory of atomism. In addition, he distinguished himself as a chemist, in the domains of: cohesion, chemical affinities, crystallization, as well as in the field of heat. For Bošković, J.J. Thomson said that he gave the best explanation of cohesion, which is accepted throughout the world. Ruđer Bošković had a significant influence on English scientists: Davy, Faraday, Maxwell, Kelvin and J. Thomson. Thompson also said that Boskovic's work was so advanced that it had the greatest influence on Davy and Farday's future research. Ruđer Bošković started and Michael Faraday finished the theory of chemical elements and electrolytes. In his time, Bošković published 70 scientific works, in which he dealt with the fields of optics, gravity, trigonometry, astronomy and meteorology. Prominent in the domains of atomic theory, Maxwell wrote about Bošković in Natura magazine in 1877: "The best thing we can do is to get rid of the concept of the nucleus and replace it with Ruđer Bošković's atom." Lord Kelvin believed that Bošković's ideas were absolute and that his theory was unlimited.

Bošković is considered a pioneer of geodetic science and was the first to initiate the measurement of earth's nereids. He also lived in France and became a member of the French Academy of Sciences, and was a member of the Royal Society of Rome. In addition to everything he did in science, he advocated extremely well for his country, so during his stay in Rome he was also the official diplomatic representative of Dubrovnik. Note: Croats consider Ruđer Bošković as their own, because they need him as such, although according to the available data, it seems that he is of Serbian origin.

JOSEPH BLACK (1728-1799), Scottish chemist

Joseph Black studied chemistry in Edinburgh and was professor of medicine at the University of Glasgow. He was the first to discover the ability of substances to absorb heat without an increase in temperature and introduced the concept of latent heat. Latent heat is best explained in the case of ice melting, during which a constant temperature of 0°C is maintained, as is the case when water evaporates at 100°C. With this discovery, he explained the difference between heat and temperature. He is also responsible for the discovery of carbon dioxide. He extracted it from the decomposition reaction of calcium carbonate, from the process of respiration, in the process of burning coal and in the process of fermentation. In chemistry, he emphasized the importance of quantitative experimentation.

HENRY CAVENDYSH (1731-1810), English physicist

He was born in Nice, France, and studied at Cambridge University, which he did not finish. He inherited a large fortune from his parents and behaved very strangely with it. He performed experiments in physics and chemistry and published them in a large number of papers. Cavendish is credited with pioneering work in the discovery and understanding of non-flammable gasses. He also discovered the method of measuring the weight of gasses. He found that mixing two volumes of non-flammable hydrogen and one volume of oxygen produces water (2 N + O = N2O). As Cavendish himself was in no hurry to publish his discoveries, this discovery was published to him by Antoine Lavoisier (1743-1794) and James Watt (1736-1819). The importance of this evidence, that water is not an element, as believed since Aristotle, is enormous. He also proved that air also consists of one part oxygen and four parts nitrogen, and it is the same wherever the sample is taken. In addition, he proved the presence of 1% of other gasses, which he called inert gasses, since they could not be separated at that time. In addition to all the previous ones, he discovered nitric acid by dissolving nitrous oxide in water. Cavendish is considered to have been about half a century ahead of his contemporaries. Most of his discoveries remained unexplained until his notes were found and published by James Clerk Maxwell (1831-1879) after Cavendish's death. Cavendish determined the density of earth to be 5.5 times that of water. He was also involved in testing electricity, which was completed after him by Charles Coulomb (1736-1806), Georg Ohm (1789-1854) and Michael Faraday (1791-1867). Cavendish is especially praised by Mihajlo Pupin in his book "From settlers to inventors".

JOSEPH PRIESTLEY (1733-1804), English chemist

Joseph Priestley is remembered for the discoveries of several gasses, including carbon dioxide from fermentation, which he used in the production of soda water, and hydrogen, nitrous oxide (laughing gas), nitrous oxide, nitrous oxide, hydrogen chloride, carbon monoxide, sulfur dioxide, ammonia and others. His most significant discovery is certainly oxygen.

JAMES WATT (1736-1819), Scottish inventor

James Watt is most often mentioned as the first inventor of the steam engine. He isn't. The first steam engine was built by Thomas Newcomen, a quarter of a century before Watt's birth. However, Newcomen's machine was limited only to pumping water out of mine shafts, and Watt's steam engine found a very wide application and its application started the Industrial Revolution. In 1765, Watt reconstructed and improved Newcomen's engine, adding a steam condenser and maintaining a constant temperature of the working cylinder. Its mass production and application began in 1775, and in 1790 Watt completely perfected his machine by modifying it into a rotary mechanism with a centrifugal speed regulator.

CHARLES de COULOMB (1736-1806), French physicist

Charles Coulomb discovered that electricity and magnetism are two different fluids. According to his law (Coulomb's law), the forces between two charged bodies are proportional to the root of their distances. For example, by tripling the distance between charged bodies, the force decreases nine times. Also, the force is directly proportional to the product of the charges of both bodies. In other words, Newton's law of gravity was reflected in electricity. Columbus made a similar finding for magnetism, so some scientists began to wonder if there was some interdependence between gravity, electricity, and magnetism. However, Coulomb himself believed that they were different liquids. After Coulomb, Christian Oersted (1777-1851), Andre-Marie Ampere (1775-1836) and Michael Faraday (1791-1867) defined the phenomenon of electromagnetism.

In honor of the Coulomb, the SI measurement system introduced a unit of electric charge called the Coulomb, which is equal to a current flow of one ampere in one second.

JOSEPH LOUIS LAGRANGE (1736-1813), French mathematician

Joseph Lagrange is French, born in Turin, Italy. His first interest in science was based on the works of the English astronomer Edmund Halley, as well as mathematics. Later, as director of the Academy in Berlin, he became interested in the motion of the planets. He returned to Paris in 1787 and reformed the mathematical system. And after the French Revolution, it was Napoleon who personally recognized him for his achievements. Today there is a concept of Lagrangian mathematics.

LUIGI GALVANI (1737-1798), Italian scientist

Galvani, experimenting with currents, noticed that shiny drums on a metal fence produced electricity. Alessandro Volta later refuted the same, but Galvani was remembered in science by the name Galvanometer, which was given in his honor and is used to measure electric currents and by the process called galvanization, which implies surface application, of metal ions.

To be continued

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