TOKOH

Carl Friedrich Gauss

Carl Friedrich Gauss (1777-1855), German mathematician, noted for his wide-ranging contributions to physics, particularly the study of electromagnetism.

Born in Braunschweig on April 30, 1777, Gauss studied ancient languages in college, but at the age of 17 he became interested in mathematics and attempted a solution of the classical problem of constructing a regular heptagon, or seven-sided figure, with ruler and compass. He not only succeeded in proving this construction impossible, but went on to give methods of constructing figures with 17, 257, and 65,537 sides. In so doing he proved that the construction, with compass and ruler, of a regular polygon with an odd number of sides was possible only when the number of sides was a prime number of the series 3, 5, 17, 257, and 65,537 or was a multiple of two or more of these numbers. With this discovery he gave up his intention to study languages and turned to mathematics. He studied at the University of Göttingen from 1795 to 1798; for his doctoral thesis he submitted a proof that every algebraic equation has at least one root, or solution. This theorem, which had challenged mathematicians for centuries, is still called “the fundamental theorem of algebra. His volume on the theory of numbers, Disquisitiones Arithmeticae (Inquiries into Arithmetic, 1801), is a classic work in the field of mathematics.

Gauss next turned his attention to astronomy. A faint planetoid, Ceres, had been discovered in 1801; and because astronomers thought it was a planet, they observed it with great interest until losing sight of it. From the early observations Gauss calculated its exact position, so that it was easily rediscovered. He also worked out a new method for calculating the orbits of heavenly bodies. In 1807 Gauss was appointed professor of mathematics and director of the observatory at Göttingen, holding both positions until his death there on February 23, 1855.

Although Gauss made valuable contributions to both theoretical and practical astronomy, his principal work was in mathematics and mathematical physics. In theory of numbers, he developed the important prime-number theorem. He was the first to develop a non-Euclidean geometry, but Gauss failed to publish these important findings because he wished to avoid publicity. In probability theory, he developed the important method of least squares and the fundamental laws of probability distribution. The normal probability graph is still called the Gaussian curve. He made geodetic surveys, and applied mathematics to geodesy. With the German physicist Wilhelm Eduard Weber, Gauss did extensive research on magnetism. His applications of mathematics to both magnetism and electricity are among his most important works; the unit of intensity of magnetic fields is today called the gauss. He also carried out research in optics, particularly in systems of lenses. Scarcely a branch of mathematics or mathematical physics was untouched by Gauss.

Archimedes

Archimedes (287-212 bc), preeminent Greek mathematician and inventor, who wrote important works on plane and solid geometry, arithmetic, and mechanics.

Archimedes was born in Syracuse, Sicily, and educated in Alexandria, Egypt. In pure mathematics he anticipated many of the discoveries of modern science, such as the integral calculus, through his studies of the areas and volumes of curved solid figures and the areas of plane figures. He also proved that the volume of a sphere is two-thirds the volume of a cylinder that circumscribes the sphere.

In mechanics, Archimedes defined the principle of the lever and is credited with inventing the compound pulley. During his stay in Egypt he invented the hydraulic screw for raising water from a lower to a higher level. He is best known for discovering the law of hydrostatics, often called Archimedes' principle, which states that a body immersed in fluid loses weight equal to the weight of the amount of fluid it displaces. This discovery is said to have been made as Archimedes stepped into his bath and perceived the displaced water overflowing.

Archimedes spent the major part of his life in Sicily, in and around Syracuse. He did not hold any public office but devoted his entire lifetime to research and experiment. During the Roman conquest of Sicily, however, he placed his gifts at the disposal of the state, and several of his mechanical devices were employed in the defense of Syracuse. Among the war machines attributed to him are the catapult and—perhaps legendary—a mirror system for focusing the sun's rays on the invaders' boats and igniting them.

After the capture of Syracuse during the Second Punic War, Archimedes was killed by a Roman soldier who found him drawing a mathematical diagram in the sand. It is said that Archimedes was so absorbed in calculation that he offended the intruder merely by remarking, “Do not disturb my diagrams.” Several of his works on mathematics and mechanics survive, including Floating Bodies, The Sand Reckoner, Measurement of the Circle, Spirals, and Sphere and Cylinder. They all exhibit the rigor and imaginativeness of his mathematical thinking.

Michael Faraday

Michael Faraday (1791-1867), British physicist and chemist, best known for his discoveries of electromagnetic induction and of the laws of electrolysis.

Faraday was born on September 22, 1791, in Newington, Surrey, England. He was the son of a blacksmith and received little formal education. While apprenticed to a bookbinder in London, he read books on scientific subjects and experimented with electricity. In 1812 he attended a series of lectures given by the British chemist Sir Humphry Davy and forwarded the notes he took at these lectures to Davy, together with a request for employment. Davy employed Faraday as an assistant in his chemical laboratory at the Royal Institution and in 1813 took Faraday with him on an extended tour of Europe. Faraday was elected to the Royal Society in 1824 and the following year was appointed director of the laboratory of the Royal Institution. In 1833 he succeeded Davy as professor of chemistry at the institution. Two years later he was given a pension of 300 pounds per year for life. Faraday was the recipient of many scientific honors, including the Royal and Rumford medals of the Royal Society; he was also offered the presidency of the society but declined the honor. He died on August 25, 1867, near Hampton Court, Surrey.

Faraday's earliest researches were in the field of chemistry, following the lead of Davy. A study of chlorine, which Faraday included in his researches, led to the discovery of two new chlorides of carbon. He also discovered benzene. Faraday investigated a number of new varieties of optical glass. In a series of experiments he was successful in liquefying a number of common gases (see Cryogenics).

The research that established Faraday as the foremost experimental scientist of his day was, however, in the fields of electricity and magnetism. In 1821 he plotted the magnetic field around a conductor carrying an electric current; the existence of the magnetic field had first been observed by the Danish physicist Hans Christian Oersted in 1819. In 1831 Faraday followed this accomplishment with the discovery of electromagnetic induction and in the same year demonstrated the induction of one electric current by another. During this same period of research he investigated the phenomena of electrolysis (see Electrochemistry) and discovered two fundamental laws: that the amount of chemical action produced by an electrical current in an electrolyte is proportional to the amount of electricity passing through the electrolyte; and that the amount of a substance deposited from an electrolyte by the action of a current is proportional to the chemical equivalent weight of the substance. Faraday also established the principle that different dielectric substances have different specific inductive capacities (see Dielectric).

In experimenting with magnetism, Faraday made two discoveries of great importance; one was the existence of diamagnetism, and the other was the fact that a magnetic field has the power to rotate the plane of polarized light passing through certain types of glass.

In addition to a number of papers for learned journals, Faraday wrote Chemical Manipulation (1827), Experimental Researches in Electricity (1844-1855), and Experimental Researches in Chemistry and Physics (1859).

Guglielmo Marconi

Guglielmo Marconi (1874-1937), Italian electrical engineer and Nobel laureate, known as the inventor of the first practical radio-signaling system. He was born in Bologna and educated at the University of Bologna. As early as 1890 he became interested in wireless telegraphy, and by 1895 he had developed an apparatus with which he succeeded in sending signals to a point a few kilometers away by means of a directional antenna. After patenting his system in Great Britain, he formed (1897) Marconi's Wireless Telegraph Company, Ltd., in London. In 1899 he established communication across the English Channel between England and France, and in 1901 he communicated signals across the Atlantic Ocean between Poldhu, in Cornwall, England, and St. John's, in Newfoundland. His system was soon adopted by the British and Italian navies, and by 1907 had been so much improved that transatlantic wireless telegraph service was established for public use. Marconi was awarded honors by many countries and received, jointly with the German physicist Karl Ferdinand Braun, the 1909 Nobel Prize in physics for his work in wireless telegraphy. During World War I he was in charge of the Italian wireless service and developed shortwave transmission as a means of secret communication. In the remaining years of his life he experimented with shortwaves and microwaves.