crème de la crème

Jai Ganesh · 2018-05-04 00:54:05

318) Axel Fredrik Cronstedt

Axel Fredrik Cronstedt, (born Dec. 23, 1722, Turinge, Sweden—died Aug. 19, 1765, Säter), Swedish mineralogist and chemist noted for his work on the chemistry of metallic elements and for his efforts to establish a new mineralogical system. He is also credited with developing an experimental procedure involving the systematic use of blowpipes for analyzing the chemical composition of minerals.

Cronstedt was the first to isolate nickel (1751). He also made a detailed analysis of calcium tungstate, a previously unknown mineral of high specific gravity, and studied the properties of gypsum and a hydrous mineral he named zeolite. Such experiments revealed certain laws governing the internal structure of minerals and enabled him to establish a distinction between simple minerals and rock minerals, which are composed of a mixture of several minerals.

Jai Ganesh · 2018-05-06 01:19:34

319) Johan August Arfwedson

Johan August Arfwedson was born in Skagersholm, Sweden, on January 12, 1792, to a wealthy merchant family. He was homeschooled as a child, and at the age of 14, he started to study law and mining sciences at the University of Uppsala, Sweden. In 1812, he joined the Royal College of Mines in Stockholm, Sweden.

In Stockholm, Arfwedson met Jöns Jacob Berzelius, who established the law of constant proportions and today is considered one of the founders of modern chemistry. Arfwedson joined his laboratory and started to work on the analysis of minerals. He investigated, e.g., the composition of manganese oxides.

In 1817, Arfwedson started his work on petalit, a mineral that had been found in an iron mine on the island Utö south of Stockholm. Petalit has the composition LiAlSi4O10. Arfwedson successfully determined the silica and alumina content, but together, these accounted for only 96 % of the mineral's weight. After further experiments, Arfwedson and Berzelius concluded that the missing part must be a new alkali metal, which they termed "lithium" (stone metal).

Arfwedson prepared several lithium salts but was not able to isolate the element in its metallic form. The first isolation of lithium was achieved by Sir Humphrey Davy and William Thomas Brande in 1818, who performed an electrolysis of lithium oxide (Li2O) and obtained small amounts of the metal.

In 1819, Arfwedson set up his own laboratory. However, he owned several industrial plants and had little free time to pursue his research. Nevertheless, he published analyses of minerals such as cyanite, sodalite, and chrysoberyl, as well as of several uranium compounds. In 1823, the British scientist Henry James Brooke named a newly discovered mineral "arfvedsonite" to honor Arfwedson's contributions to mineralogy. Johan August Arfwedson died on October 28, 1841, in Hedensö, Sweden.

Jai Ganesh · 2018-05-08 01:18:13

320) William Stanley Jr.

William Stanley Jr. (November 28, 1858 – May 14, 1916) was an American physicist born in Brooklyn, New York. In his career, he obtained 129 patents covering a variety of electric devices. In 1913, he also patented an all-steel vacuum bottle, and formed the Stanley Bottle Company.

Early life

Stanley was born November 28, 1858 in Brooklyn, NY, the son of William Stanley and Elizabeth A. Parsons Stanley. William Jr. attended Williston Seminary and later graduated from Yale University with the class of 1881.

Career

Stanley was as an electrician working with tele keys and fire alarms of an early manufacturer. In Philadelphia, Stanley designed one of the first electrical installations (at a Fifth Avenue store). Shortly thereafter, George Westinghouse hired Stanley as his chief engineer at his Pittsburgh factory.

In 1885, Stanley built the first practical alternating current device based on Lucien Gaulard and John Dixon Gibbs' idea. This device was the precursor to the modern transformer. In December, under a new contract with Westinghouse, Stanley moved his operations to Great Barrington, Massachusetts.

In 1886, on March 20, Stanley demonstrated the first complete system of high voltage Alternating Current transmission, consisting of generators, transformers and high-voltage transmission lines. His system allowed the distribution of electrical power over wide areas. He used the system to light offices and stores along the main street of Great Barrington - the location of his West Avenue family home. Stanley's transformer design became the prototype for all future transformers, and his AC distribution system formed the basis of modern electrical power distribution. He was the first person to make an electrical transformer, and his work in the electrification of Great Barrington's Main Street was named an IEEE Milestone.

Agreeing that the AC system had arrived, Westinghouse further tested the system in summer 1886 in Pittsburgh; it transmitted over a distance of 3 miles, and used an alternator designed by Stanley to replace the Siemens model, which regulated voltage poorly. Satisfied with the pilot system, Westinghouse began commercial production and shipped his company's first commercial to Buffalo NY, where a local utility placed it in service. Orders for 25 alternating-current plants followed within months.

In 1890, Stanley founded the Stanley Electric Manufacturing Company in Pittsfield, Massachusetts. In 1903 the General Electric Corporation purchased a controlling interest in the firm. The land on which the company once stood is now the site of the William Stanley Business Park of the Berkshires in Pittsfield.

Jai Ganesh · 2018-05-09 15:10:19

321) Hideki Yukawa

Hideki Yukawa, (born January 23, 1907, Tokyo, Japan—died September 8, 1981, Kyōto), Japanese physicist and recipient of the 1949 Nobel Prize for Physics for research on the theory of elementary particles.

Yukawa graduated from Kyōto Imperial University (now Kyōto University) in 1929 and became a lecturer there; in 1933 he moved to Ōsaka Imperial University (now Ōsaka University), where he earned his doctorate in 1938. He rejoined Kyōto Imperial University as a professor of theoretical physics (1939–50), held faculty appointments at the Institute for Advanced Study in Princeton, New Jersey (U.S.), and at Columbia University in New York City, and became director of the Research Institute for Fundamental Physics in Kyōto (1953–70).

In 1935, while a lecturer at Ōsaka Imperial University, Yukawa proposed a new theory of the strong and weak nuclear forces in which he predicted a new type of particle as those forces’ carrier particle. He called it the U-quantum, and it was later known as the meson because its mass was between those of the electron and proton. American physicist Carl Anderson’s discovery in 1937 of a particle among cosmic rays with the mass of the predicted meson suddenly established Yukawa’s fame as the founder of meson theory, which later became an important part of nuclear and high-energy physics. However, by the mid-1940s, it was discovered that Anderson’s new particle, the muon, could not be the predicted carrier particle. The predicted particle, the pion, was not discovered until 1947 by British physicist Cecil Powell, but, despite Yukawa’s successful prediction of the pion’s existence, it also was not the carrier particle of the nuclear forces, and meson theory was supplanted by quantum chromodynamics.

After devoting himself to the development of meson theory, Yukawa started work in 1947 on a more comprehensive theory of elementary particles based on his idea of the so-called nonlocal field.

Mathegocart · 2018-05-09 23:05:49

Hi, this is intriguing.

Last edited by Mathegocart (2018-05-09 23:06:09)

Jai Ganesh · 2018-05-11 01:34:14

Hi,

Thanks, Mathegocart!

322) Willem Einthoven

Willem Einthoven, (born May 21, 1860, Semarang, Java, Dutch East Indies—died Sept. 29, 1927, Leiden, Neth.), Dutch physiologist who was awarded the 1924 Nobel Prize for Physiology or Medicine for his discovery of the electrical properties of the heart through the electrocardiograph, which he developed as a practical clinical instrument and an important tool in the diagnosis of heart disease.

Einthoven was graduated in medicine from the University of Utrecht and served as professor of physiology at the University of Leiden from 1886 until his death. In 1903 he devised the first string galvanometer, known as the Einthoven galvanometer; with this instrument he was able to measure the changes of electrical potential caused by contractions of the heart muscle and to record them graphically. He coined the term electrocardiogram for this process. Einthoven recognized differences in the records or tracings obtained from different kinds of heart disease. From 1908 to 1913 he studied the patterns of records of normal heart activity in order to gain precision in recognizing and interpreting deviations.

Einthoven continued to develop electrode arrangements, and the present-day standard limb leads were originally described and used by him. The clinical application of Einthoven’s instrument was pioneered by the British physician Sir Thomas Lewis, with whom Einthoven maintained a long and fruitful correspondence.

Jai Ganesh · 2018-05-13 01:02:59

323) David Hughes

David Hughes, in full David Edward Hughes, (born May 16, 1831, London, England—died January 22, 1900, London), Anglo-American inventor of the carbon microphone, which was important to the development of telephony.

Hughes’s family emigrated to the United States when he was seven years old. In 1850 he became professor of music at St. Joseph’s College, Bardstown, Kentucky. Five years later he took out a U.S. patent for a type-printing telegraph instrument; its success was immediate, and in 1857 Hughes took it to Europe, where it came into widespread use and in some places continued in use until the 1930s. Hughes’s microphone, invented in 1878, was the forerunner of the various carbon microphones that were used in most telephones produced in the 20th century.

From 1879 to 1886 Hughes performed a series of experiments in which his equipment transmitted wireless signals up to 500 yards. The observed effects were attributed to induction by other scientists. Hughes disagreed but did not know how the transmissions were working. It was not realized until 1899, after German physicist Heinrich Hertz’s radio wave experiments in the late 1880s, that Hughes had been the first to produce radio waves.

Jai Ganesh · 2018-05-15 00:59:02

324) Smithson Tennant

Smithson Tennant was born on November 30, 1761 – died on February 22, 1815. Tennant is best known for his discovery of the elements iridium and osmium. He also contributed to the proof of the identity of diamond and charcoal. The mineral tennantite is named after him.

Following research work done by tenant which leads to the discovery of osmium and iridium elements.

Tennant fused the insoluble residue with alkali at high temperature and dissolved the resulting cooled solid in water, producing a further black solid and a yellow solution. The yellow solution was probably a basic form of osmium tetroxide, OsO4. The black solid was further treated with hydrochloric acid, the solid produced was fused with caustic soda and further treatment with acid obtained red crystals. These are most likely to have been Na2[IrCl6].nH2O. On heating these, a white powder of an unknown element was obtained, which was later identified as iridium element.

Osmium is a hard, brittle, bluish-white transition metal in the platinum group. Its alloys with platinum, iridium and other platinum group metals are employed in fountain pen nibs, electrical contacts, and other applications. Osmium is a hard but brittle metal that remains lustrous even at high temperatures. It has a very low compressibility. The most common oxidation states of osmium element include +2, +3, +4, and +8. It can be dissolved by fused alkalies, especially if an oxidizing agent such as sodium chlorate is present. Osmium will react at 200° C with air or oxygen to form OsO4. Osmium has high reflectivity in the ultraviolet range of the electromagnetic spectrum.

Iridium is a very hard, brittle, silvery-white transition metal of the platinum family. It is the only metal to maintain good mechanical properties in air at temperatures above 1600 °C. The most important iridium compounds in use are the salts and acids it forms with chlorine, though iridium also forms a number of organometallic compounds used in industrial catalysis, and in research. Iridium metal is employed when high corrosion resistance at high temperatures is needed, as in high-performance spark plugs, crucibles for recrystallization of semiconductors at high temperatures, and electrodes for the production of chlorine in the chloralkali process. Iridium radioisotopes are used in some radioisotope thermoelectric generators.

Iridium forms compounds in oxidation states between −3 and +9. Iridium has two naturally occurring, stable isotopes, 191Ir and 193Ir, with natural abundances of 37.3% and 62.7%, respectively. Iridium is one of the nine least abundant stable elements in Earth's crust, having an average mass fraction of 0.001 ppm in crustal rock. Iridium is obtained commercially as a by-product from nickel and copper mining and processing.

Jai Ganesh · 2018-05-17 01:18:40

325) Clarence Birdseye

Clarence Birdseye, (born December 9, 1886, New York, New York, U.S.—died October 7, 1956, New York), American businessman and inventor best known for developing a process for freezing foods in small packages suitable for retailing.

After working as a government naturalist, Birdseye went to Labrador as a fur trader in 1912 and again in 1916. There the people often froze food in the winter because of the difficulty of obtaining fresh food; this solution to their problem spurred Birdseye’s imagination.

After returning to the United States, he began to experiment and, in 1924, helped found General Seafoods Company. Five years later he began selling his quick-frozen foods, a successful line of products that made him wealthy. Birdseye’s process consisted of rapid freezing of packaged food between two refrigerated metal plates. Though his were not the first frozen foods, Birdseye’s freezing process was a highly efficient one that preserved the original taste of a variety of foods, including fish, fruits, and vegetables. In 1929 Birdseye’s company was bought by Postum, Inc., which changed its own name to the General Foods Corporation, retaining Birdseye as a consultant. From 1930 to 1934 Birdseye was president of Birds Eye Frosted Foods and from 1935 to 1938, of Birdseye Electric Company.

Birdseye held nearly 300 patents. Besides his frozen food process, he developed infrared heat lamps, a recoilless harpoon gun for taking whales, and a method of removing water from foods. A few years before his death he perfected a method of converting bagasse (crushed sugarcane residue) into paper pulp.

Jai Ganesh · 2018-05-19 01:11:20

326) Abraham-Louis Breguet

Abraham-Louis Breguet, (born Jan. 10, 1747, Neuchatel, Switz.—died Sept. 17, 1823, Paris), the leading French horologist of his time, known for the profusion of his inventions and the impeccable style of his designs.

Breguet was apprenticed in 1762 to a watchmaker at Versailles. He took refuge in Switzerland during the French Revolution and, upon his return to France, became a principal watchmaker of the empire. Among Breguet’s many inventions and innovations were the overcoil, an improvement of the balance spring that was incorporated into many precision watches, and the tourbillon, an improvement that rendered the escapement immune to errors caused by the changing position of the watch while being carried. Breguet succeeded Pierre-Louis Berthoud as the official chronometer maker to the French navy in 1815 and was admitted to the French Academy of Sciences in 1816. Considered to be one of the greatest watchmakers of all time, Breguet had in his lifetime a worldwide reputation and clientele, and he influenced watchmaking throughout Europe.

Jai Ganesh · 2018-05-21 01:26:17

327) Thomas Romney Robinson

Rev John Thomas Romney Robinson (23 April 1792 – 28 February 1882), usually referred to as Thomas Romney Robinson, was a 19th-century astronomer and physicist. He was the longtime director of the Armagh Astronomical Observatory, one of the chief astronomical observatories in the UK of its time.

His is remembered as inventor of the 4-cup anemometer.

Biography

Robinson was born at St Anne's in Dublin, the son of the English portrait painter Thomas Robinson (d.1810) and his wife, Ruth Buck (d.1826). He was educated at Belfast Academy then studied Divinity at Trinity College, Dublin, where he was elected a Scholar in 1808, graduating BA in 1810 and obtaining a fellowship in 1814, at the age of 22. He was for some years a deputy professor of natural philosophy (physics) at Trinity.

Having been also ordained as an Anglican priest while at Trinity, he obtained the church livings of the Anglican Church at Enniskillen and at Carrickmacross in 1824.

In 1823, now aged 30, he additionally gained the appointment of astronomer at the Armagh observatory. From then on he always resided at the Armagh observatory, engaged in researches connected with astronomy and physics, until his death in 1882.

During the 1840s and 1850s Robinson was a frequent visitor to the world's most powerful telescope of that era, the so-called Leviathan of Parsonstown telescope, which had been built by Robinson's friend and colleague William Parsons, 3rd Earl of Rosse. Robinson was active with Parsons in interpreting the higher-resolution views of the night sky produced by Parsons' telescope, particularly with regard to the galaxies and nebulae and he published leading-edge research reports on the question. Back at his own observatory in Armagh, Robinson compiled a large catalogue of stars and wrote many related reports. In 1862 he was awarded a Royal Medal "for the Armagh catalogue of 5345 stars, deduced from observations made at the Armagh Observatory, from the years 1820 up to 1854; for his papers on the construction of astronomical instruments in the memoirs of the Astronomical Society, and his paper on electromagnets in the Transactions of the Royal Irish Academy".

Robinson is also of note as the inventor of a device for measuring the speed of the wind, the Robinson cup-anemometer (1846).

He was president of the Royal Irish Academy from 1851 to 1856, and was a long-time active organiser in the British Association for the Advancement of Science.

Robinson was a friend of Charles Babbage, who said was "indebted" for having reminded him about the first time he came up with the idea of the calculating machine.

Family

He married twice: first Eliza Isabelle Rambaut (d.1839) and secondly Lucy Jane Edgeworth (1806–1897), the lifelong disabled daughter of Richard Lovell Edgeworth. His daughter married the physicist George Gabriel Stokes. Stokes frequently visited Robinson in Armagh in Robinson's later years.

Recognition

On the Moon, the crater Robinson (crater) is named in his honour.

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Jai Ganesh · 2018-05-23 17:30:47

328) Sir Charles Wheatstone

Sir Charles Wheatstone, (born Feb. 6, 1802, Gloucester, Gloucestershire, Eng.—died Oct. 19, 1875, Paris), English physicist who popularized the Wheatstone bridge, a device that accurately measured electrical resistance and became widely used in laboratories.

Wheatstone was appointed professor of experimental philosophy at King’s College, London, in 1834, the same year that he used a revolving mirror in an experiment to measure the speed of electricity in a conductor. The same revolving mirror, by his suggestion, was later used in measurements of the speed of light. Three years later, with Sir William Fothergill Cooke of England, he patented an early telegraph. In 1843, he brought to notice the Wheatstone bridge, a device invented by British mathematician Samuel Christie.

His own inventions include the concertina, a type of small accordion, and the stereoscope, a device for observing pictures in three dimensions still used in viewing X-rays and aerial photographs. He initiated the use of electromagnets in electric generators and invented the Playfair cipher, which is based on substituting different pairs of letters for paired letters in the message. He was knighted in 1868.

Jai Ganesh · 2018-05-25 02:37:20

329) Robert William Thomson

Robert William Thomson, (born June 29, 1822, Stonehaven, Kincardineshire, Scotland—died March 8, 1873, Edinburgh), Scottish engineer and entrepreneur, inventor of the pneumatic tire.

Thomson was the son of the owner of a woollen mill and was sent at age 14 to Charleston, South Carolina, U.S., to live with an uncle and learn the merchant’s trade. Two years later he returned to Scotland, where he worked on various inventions, apprenticed in engineering workshops in Aberdeen and Dundee, and learned civil engineering in Edinburgh and Glasgow. While working in Edinburgh, he invented a system for detonating demolition explosives by electricity. Thomson then went to London and joined the South Eastern Railway Company, where he worked under prominent engineers Sir William Cubitt and Robert Stephenson (the latter the son of pioneering railway engineer George Stephenson).

In 1845 Thomson acquired a patent for a pneumatic tire—actually a hollow leather tire enclosing a rubberized fabric tube filled with air. Although a set of Thomson’s “aerial wheels” ran for 1,200 miles (roughly 2,000 km) on an English brougham, rubber for the inner tubes was so expensive that the tires could not be made profitably, and, thus, for almost half a century, air-filled tires were forgotten. The growing popularity of the bicycle later in the century revived interest in tire design, and in 1888 John Boyd Dunlop, a Scottish veterinarian living in Belfast, obtained patents on a pneumatic tire for bicycles, tricycles, and other vehicles. Dunlop later lost his main patent after it was discovered that Thomson had already patented the principle of the pneumatic tire.

Thomson went on to invent a fountain pen (1849) before he went to work for an engineering firm in Java (1852–62), where he designed a mobile steam crane. Back in Scotland, he developed and put into production a steam road vehicle that ran on solid rubber tires. Thomson’s machines were used to haul heavy loads on level and inclined ground and to provide omnibus service between Edinburgh and the port town of Leith.

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Jai Ganesh · 2018-05-26 17:40:07

330) Albert Hoyt Taylor

Albert Hoyt Taylor, IRE President, 1929, was in charge of the Aircraft Radio Laboratory, and he later directed a radar development project for ships to use in order to detect enemy ships and aircraft.

Biography

Albert Hoyt Taylor was born in Chicago, IL, on 1 January 1879 and graduated from Northwestern University in 1902. He undertook his first radio investigations during 1899, which led to his first published paper in 1902. He taught at the University of Wisconsin from 1903 to 1908 before going to Germany for graduate studies. He received the Ph.D. degree from the University of Göttingen in 1909 with a thesis on aluminum rectifiers. He returned to the United States and became Professor of Physics and Department Head at the University of North Dakota, where he remained until 1917. While there he built an experimental radio station which he used in pioneering studies of wave propagation and directive antennas.

In 1917, Taylor accepted a Naval Reserve commission and was appointed District Communication Officer at the Great Lakes Naval station in Chicago. He established a laboratory and began research on the use of underground and underwater antennas for very-low-frequency radio reception. Soon afterward, he was transferred to Belmar, NJ, as transatlantic communications officer in charge of several high-power stations on the East Coast. In 1918 he was assigned to head an experimental division of the Naval Air Station at Hampton Roads, VA, where research on aircraft radio was undertaken. The following year he became head of the Aircraft Radio Laboratory at Anacostia, DC, with a staff of fifteen people. Taylor resigned from the Navy in 1922 but remained at Anacostia as a civilian employee.

At Anacostia, Taylor studied the polarization of electric waves. During 1922, Taylor and Leo Young observed reflections of high-frequency radio waves from ships on the Potomac River as they passed between a transmitter and a portable receiver. In 1930, Taylor penned a report on “radio-echo signals from moving objects” which spurred the Navy’s interest in developing radio to detect enemy ships and aircraft. This led to a radar development project directed by Taylor which yielded a 200-MHz radar ready for installation on a ship by 1937. When the Naval Research Laboratory was established in 1923, Taylor became superintendent of its Radio Division, a position he held until 1945. He participated in systematic investigations of high- frequency propagation phenomena including ionospheric effects.

Taylor received the Morris Liebmann Memorial Prize of the IRE in 1927 for his research on short waves. He served as President of the IRE in 1929 and was recipient of the IRE Medal of Honor in 1942 "For his contributions to radio communication as an engineer and organizer, including pioneering work in the practical application of piezoelectric control to radio transmitters, early recognition and investigation of skip distances and other high-frequency wave-propagation problems, and many years of service to the government of the United States as an engineering executive of outstanding ability in directing the Radio Division of the Naval Research Laboratory."

He also served on the Communication Committee of the American Institute of Electrical Engineers from 1936 to 1942.

On March 28, 1944, Secretary of State Cordell Hull presented Taylor with the Medal of Merit, one of the highest civilian decorations of the United States, for “For exceptionally meritorious conduct in the performance of outstanding services in the line of his profession as member of the staff of the Naval Research Laboratory. Undiscouraged by frequent handicaps, Dr. Taylor labored tirelessly in the course of intensive research and experimentation which eventually resulted in the discovery and development of radar. His foresight, technical skill and steadfast perseverance contributed in large measure to the timely introduction of a scientific device which has yielded the United States Navy a definite advantage over her enemies during the present war.” By the end of the war, he was popularly known as a key scientific pioneer behind the development of radar.

He retired from the Naval Research Laboratory in 1948, and wrote a book about his experiences entitled: Radio Reminscences: A Half Century.

Taylor died on 11 December 1961 at age 82 in Claremont, CA.

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Jai Ganesh · 2018-05-28 00:29:53

331) Richard Trevithick

Richard Trevithick, (born April 13, 1771, Illogan, Cornwall, England—died April 22, 1833, Dartford, Kent), British mechanical engineer and inventor who successfully harnessed high-pressure steam and constructed the world’s first steam railway locomotive (1803). In 1805 he adapted his high-pressure engine to driving an iron-rolling mill and to propelling a barge with the aid of paddle wheels.

Trevithick spent his youth at Illogan in the tin-mining district of Cornwall and attended the village school. The schoolmaster described him as “disobedient, slow and obstinate.” Early in life, however, he displayed an extraordinary talent in engineering. Because of his intuitive ability to solve problems that perplexed educated engineers, he obtained his first job as engineer to several Cornish ore mines in 1790 at the age of 19. In 1797 he married Jane Harvey of a prominent engineering family. She bore him six children, one of whom, Francis, became locomotive superintendent of the London & North Western Railway and later wrote a biography of his father.

Because Cornwall has no coalfields, high import costs obliged the ore-mine operators to exercise rigid economy in the consumption of fuel for pumping and hoisting. Cornish engineers, therefore, found it imperative to improve the efficiency of the steam engine. The massive engine then in use was the low-pressure type invented by James Watt. Inventive but cautious, Watt thought that “strong steam” was too dangerous to harness; Trevithick thought differently. He soon realized that, by using high-pressure steam and allowing it to expand within the cylinder, a much smaller and lighter engine could be built without any less power than in the low-pressure type.

In 1797 Trevithick constructed high-pressure working models of both stationary and locomotive engines that were so successful that he built a full-scale, high-pressure engine for hoisting ore. In all, he built 30 such engines; they were so compact that they could be transported in an ordinary farm wagon to the Cornish mines, where they were known as “puffer whims” because they vented their steam into the atmosphere.

Trevithick built his first steam carriage, which he drove up a hill in Camborne, Cornwall, on Christmas Eve 1801. The following March, with his cousin Andrew Vivian, he took out his historic patent for high-pressure engines for stationary and locomotive use. In 1803 he built a second carriage, which he drove through the streets of London, and constructed the world’s first steam railway locomotive at Samuel Homfray’s Penydaren Ironworks in South Wales. On February 21, 1804, that engine won a wager for Homfray by hauling a load of 10 tons of iron and 70 men along 10 miles of tramway. A second, similar locomotive was built at Gateshead in 1805, and in 1808 Trevithick demonstrated a third, the Catch-me-who-can, on a circular track laid near Euston Road in London. He then abandoned these projects, because the cast-iron rails proved too brittle for the weight of his engines.

In 1805 Trevithick adapted his high-pressure engine to driving an iron-rolling mill and propelling a barge with the aid of paddle wheels. His engine also powered the world’s first steam dredgers (1806) and drove a threshing machine on a farm (1812). Such engines could not have succeeded without the improvements Trevithick made in the design and construction of boilers. For his small engines, he built a boiler and engine as a single unit, but he also designed a large wrought-iron boiler with a single internal flue, which became known throughout the world as the Cornish type. It was used in conjunction with the equally famous Cornish pumping engine, which Trevithick perfected with the aid of local engineers. The latter was twice as economic as the Watt type, which it rapidly replaced.

Trevithick, a quick-tempered and impulsive man, was entirely lacking in business sense. An untrustworthy partner caused the failure of a London business he started in 1808 for the manufacture of a type of iron tank Trevithick had patented; bankruptcy followed in 1811. Three years later, nine of Trevithick’s engines were ordered for the Peruvian silver mines, and, dreaming of unlimited mineral wealth in the Andes Mountains, he sailed to South America in 1816. After many adventures, he returned to England in 1827, penniless, to find that in his absence other engineers, notably George Stephenson, had profited from his inventions. He died in poverty and was buried in an unmarked grave.

Jai Ganesh · 2018-05-29 00:23:20

332) Antoine-Jérôme Balard

Antoine-Jérôme Balard, (born Sept. 30, 1802, Montpellier, Fr.—died March 30, 1876, Paris), French chemist who in 1826 discovered the element bromine, determined its properties, and studied some of its compounds. Later he proved the presence of bromine in sea plants and animals.

In studying salt marsh flora from Mediterranean waters, Balard, after crystallizing sodium chloride and sodium sulfate from the seawater, saturating the residue with chlorine, and distilling the product, discovered the only liquid nonmetallic element, bromine.

An exponent of the potential value of the sea as a source of chemicals, Balard taught at Montpellier École de Pharmacie, from which he had graduated in 1826. He became professor of chemistry at the Sorbonne (1842) and at the Collège de France, Paris (1851).

Jai Ganesh · 2018-05-31 01:12:39

333) Reginald Aubrey Fessenden

Reginald Aubrey Fessenden, (born October 6, 1866, Milton, Canada East [now Quebec], Canada—died July 22, 1932, Hamilton, Bermuda), Canadian radio pioneer who on Christmas Eve in 1906 broadcast the first program of music and voice ever transmitted over long distances.

The son of an Anglican minister, Fessenden studied at Trinity College School in Port Hope, Ontario, and at Bishop’s College in Lennoxville, Quebec (where he taught in addition to studying). Before completing his degree, he took a job as principal of the Whitney Institute, a then recently established school in Bermuda. There he met Helen Trott, who would later become his wife, and developed an interest in science that led him to resign his teaching post and go to New York City. In 1886 he began working as a tester at the Edison Machine Works. He met Thomas Edison and in 1887 went to work at the new Edison Laboratory in West Orange, New Jersey, where he became chief chemist. In 1890 he was laid off from the Edison Laboratory and went to work for the Westinghouse Electric Company in Newark, New Jersey. In 1891 he transferred to the Stanley Company, a small electric company in Pittsfield, Massachusetts. In 1892 that company folded, and Fessenden turned to an academic career as professor of electrical engineering, first at Purdue University, West Lafayette, Indiana, and then at the Western University of Pennsylvania (now the University of Pittsburgh), where he received funding from the Westinghouse company and worked on the problem of wireless communication.

In 1900 Fessenden left the university to conduct experiments in wireless telegraphy for the U.S. Weather Bureau, which wanted to adapt radiotelegraphy to weather forecasting. Impatient with the simple on-off transmission of Morse Code signals, he became interested in transmitting continuous sound, particularly that of the human voice. He developed the idea of superimposing an electric signal, oscillating at the frequencies of sound waves, upon a radio wave of constant frequency, so as to modulate the amplitude of the radio wave into the shape of the sound wave. (This is the principle of amplitude modulation, or AM.) The receiver of this combined wave would separate the modulating signal from the carrier wave and reproduce the sound for the listener. On December 23, 1900, on Cobb Island in the Potomac River in Maryland, Fessenden succeeded in transmitting a brief, intelligible voice message between two stations located about 1 mile (1.6 km) apart.

Fessenden invented and patented a number of components useful for “radiotelephony” (as wireless transmission of speech was called in those days), including an electrolytic detector sensitive enough to pick up continuous radio waves. Fessenden further contributed to the development of radio by demonstrating the heterodyne principle of converting low-frequency sound signals to high-frequency wireless signals that would be more easily controlled and amplified before the original low-frequency signal was recovered by the receiver. This was the forerunner of the principle of superheterodyne reception, which made easy tuning of radio signals possible and was a critical factor for the later growth of commercial broadcasting.

In 1902 Fessenden joined two Pittsburgh financiers in organizing the National Electric Signaling Company to manufacture his inventions, which they intended to sell to customers such as the U.S. Navy or shipping companies whose far-flung operations would benefit from wireless telegraph communication. The company was also interested in competing with Guglielmo Marconi in transmitting across the Atlantic Ocean. To this end Fessenden built a station at Brant Rock, Massachusetts, and another at Machrihanish, Scotland, some 3,000 miles (5,000 km) away. He directed Ernst Alexanderson of the General Electric Company in building a 50,000-hertz alternator that could be used as a long-distance high-frequency radio transmitter.

In January 1906 Fessenden established transatlantic wireless telegraphic communication between Brant Rock and Machrihanish, though the service was variable and unreliable. Later that year he received word from Machrihanish that the Scottish station had picked up voices that were being transmitted between the Brant Rock station and another station in nearby Plymouth, Massachusetts. Before Fessenden could explore direct transatlantic voice communication, the receiving tower at Machrihanish was wrecked by a storm. Determined to demonstrate the capabilities of his system, he sent notice to the company’s wireless telegraph customers in America to tune in to the company’s frequency on Christmas Eve. Starting at 9:00 PM on December 24, wireless operators as far away as Norfolk, Virginia, were startled to hear speech and music from Brant Rock through their own receivers. Fessenden read verses from the Gospel According to Luke, played an Edison phonograph recording of Handel’s “Largo” aria, gave a violin solo, and ended the broadcast by wishing his listeners a Merry Christmas. A New Year’s Eve show, similar in content to the first, was picked up by banana boats of the United Fruit Company in the West Indies. Fessenden probably ended his broadcasts with these two shows, as he intended them to be solely for publicity.

Differences with his partners over the conduct of business led Fessenden to leave Brant Rock in 1911 and sue his former company. Abandoning work in radio, Fessenden went on to work in marine power and signaling. He has been credited with inventing a sonic depth finder, submarine signaling devices, and a turboelectric drive for battleships. In the 1920s he engaged in a long lawsuit against a group of companies that included the Radio Corporation of America, which had purchased patents from the defunct National Electric Signaling Company. With the proceeds from the settlement of that suit in 1928, Fessenden and his wife restored and moved into a historic seaside house in her native Bermuda.

quest-crystal-amplifier-popular-electronics-june-1968-2.jpg

Jai Ganesh · 2018-06-02 00:17:40

334) René-Antoine Ferchault de Réaumur

René-Antoine Ferchault de Réaumur, (born Feb. 28, 1683, La Rochelle, Fr.—died Oct. 17, 1757, Saint-Julien-du-Terroux), French scientist and foremost entomologist of the early 18th century who conducted research in widely varied fields.

In 1710 King Louis XIV put Réaumur in charge of compiling a description of the industry and natural resources of France. Réaumur devised the thermometric scale bearing his name, improved techniques for making iron and steel, and discovered the phenomenon of the regeneration of lost appendages among crayfish. The cupola furnace, still the most economical and generally used process for melting gray iron, was first built by Réaumur in 1720. In 1734 he published the first volume of his Mémoires pour servir à l’histoire des insectes (1734–42; “Memoirs Serving as a Natural History of Insects”). Five more volumes were published, and, though unfinished, his work was a milestone in entomological history.

He investigated the chemical composition of Chinese porcelain and, in 1740, devised his own formula for the so-called Réaumur porcelain. In 1752 he isolated gastric juice and investigated its role in the digestion of food.

Jai Ganesh · 2018-06-04 00:39:36

335) Guillermo González Camarena

Guillermo González Camarena (17 February 1917 – 18 April 1965), was a Mexican electrical engineer who was the inventor of a color-wheel type of color television, and who also introduced color television to Mexico.

Early life

Born in Guadalajara in 1917, his family moved to Mexico City when Guillermo was almost 2 years old. As a boy he made electrically propelled toys, and at the age of twelve built his first amateur radio.

González Camarena was born into a family composed of Arturo González and Sara Camarena, originally from Arandas, Jalisco. One of his older brothers, Jorge, was a prominent painter, muralist and sculptor.

In 1945 he graduated from the Escuela Superior de Ingenería Mecánica y Eléctrica (School of Mechanical and Electrical Engineers, ESIME).

Career and inventions

González Camarena invented the "Chromoscopic a for television equipment", an early color television transmission system. He was only 17. A U.S. patent application (2,296,019) states, "My invention relates to the transmission and reception of colored pictures or images by wire or wireless..." The invention was designed to be easy to adapt to black-and-white television equipment. González Camarena applied for this patent August 14, 1941, and obtained the patent September 15, 1942. He also filed for additional patents for color television systems in 1960 and 1962.

On August 31, 1946, González Camarena sent his first color transmission from his lab in the offices of The Mexican League of Radio Experiments, at Lucerna St. #1, in Mexico City. The video signal was transmitted at a frequency of 115 MHz. and the audio in the 40-meter band.

He obtained authorization to make the first publicly announced color broadcast in Mexico, on February 8, 1963, Paraíso Infantil, on Mexico City's XHGC-TV, a station that he established in 1952. By that time, the government had adopted NTSC as the television color system.

Death

He died in a car accident in Puebla on April 18, 1965, returning from inspecting a television transmitter in Las Lajas, Veracruz.

Legacy

A field-sequential color television system similar to his Tricolor system was used in NASA's Voyager mission in 1979, to take pictures and video of Jupiter.

In 1995, a Mexican science research and technology group created La Fundación Guillermo González Camarena (The Guillermo González Camarena Foundation), which benefits creative and talented inventors in Mexico.

At the same time, the IPN began construction on the Centro de Propiedad Intelectual "Guillermo González Camarena" (Guillermo González Camarena Intellectual Property Center).

Jai Ganesh · 2018-06-06 00:54:10

336) Nicéphore Niépce

Nicéphore Niépce, in full Joseph-Nicéphore Niépce, (born March 7, 1765, Chalon-sur-Saône, France—died July 5, 1833, Chalon-sur-Saône), French inventor who was the first to make a permanent photographic image.

The son of a wealthy family suspected of royalist sympathies, Niépce fled the French Revolution but returned to serve in the French army under Napoleon Bonaparte. Dismissed because of ill health, he settled near his native town of Chalon-sur-Saône, where he remained engaged in research for the rest of his life.

In 1807 Niépce and his brother Claude invented an internal-combustion engine, which they called the Pyréolophore, explaining that the word was derived from a combination of the Greek words for “fire,” “wind,” and “I produce.” Working on a piston-and-cylinder system similar to 20th-century gasoline-powered engines, the Pyréolophore initially used lycopodium powder for fuel, and Niépce claimed to have used it to power a boat.

When lithography became a fashionable hobby in France in 1813, Niépce began to experiment with the then-novel printing technique. Unskilled in drawing, and unable to obtain proper lithographic stone locally, he sought a way to provide images automatically. He coated pewter with various light-sensitive substances in an effort to copy superimposed engravings in sunlight. From this he progressed in April 1816 to attempts at photography, which he called heliography (sundrawing), with a camera. He recorded a view from his workroom window on paper sensitized with silver chloride but was only partially able to fix the image. Next he tried various types of supports for the light-sensitive material bitumen of Judea, a kind of asphalt, which hardens on exposure to light. Using this material he succeeded in 1822 in obtaining a photographic copy of an engraving superimposed on glass. In 1826/27, using a camera, he made a view from his workroom on a pewter plate, this being the first permanently fixed image from nature. Metal had the advantage of being unbreakable and was better suited to the subsequent etching process to produce a printing plate, which was Niépce’s final aim. In 1826, he had produced another heliograph, a reproduction of an engraved portrait, which was etched by the Parisian engraver Augustin-François Lemaître, who pulled two prints. Thus Niépce not only solved the problem of reproducing nature by light, but he invented the first photomechanical reproduction process. While on a visit to England in 1827, Niépce addressed a memorandum on his invention to the Royal Society, London, but his insistence on keeping the method secret prevented the matter from being investigated.

Unable to reduce the very long exposure times by either chemical or optical means, Niépce in 1829 finally gave in to the repeated overtures of Louis-Jacques-Mandé Daguerre, a Parisian painter, for a partnership to perfect and exploit heliography. Niépce died without seeing any further advance, but, building on his knowledge, and working with his materials, Daguerre eventually succeeded in greatly reducing the exposure time through his discovery of a chemical process for development of (making visible) the latent (invisible) image formed upon brief exposure.

Jai Ganesh · 2018-06-08 00:13:37

337) Nicolas-Louis Vauquelin

Nicolas-Louis Vauquelin, (born May 16, 1763, Saint-André-d’Hébertot, France—died Nov. 14, 1829, Saint-André-d’Hébertot), French chemist who discovered the elements chromium (1797) and beryllium (1798).

A peasant’s son, Vauquelin went to work in an apothecary shop, where he was befriended by Antoine-François Fourcroy, who made him his laboratory assistant (1783–91). Vauquelin began publishing on his own authority in 1790 and was associated with 376 scientific papers. His teaching and consultative posts date from 1794. In 1809 he succeeded Fourcroy as chemistry professor at the Paris Faculty of Medicine.

Vauquelin detected chromium in a lead ore from Siberia and beryllium in beryl. His other chemical discoveries included quinic acid, asparagine (the first amino acid to be isolated), camphoric acid, and other naturally occurring compounds. In 1827 he was elected to the Chamber of Deputies. Vauquelin is also remembered as the sponsor of Louis-Jacques Thenard, another peasant’s son who became a famous chemist.

Jai Ganesh · 2018-06-10 00:22:39

338) Harold C. Urey

Harold C. Urey, in full Harold Clayton Urey, (born April 29, 1893, Walkerton, Ind., U.S.—died Jan. 5, 1981, La Jolla, Calif.), American scientist awarded the Nobel Prize for Chemistry in 1934 for his discovery of the heavy form of hydrogen known as deuterium. He was a key figure in the development of the atomic bomb and made fundamental contributions to a widely accepted theory of the origin of the Earth and other planets.

Background And Early Life

Urey was one of three children of Samuel Clayton Urey and Cora Rebecca Reinsehl. The elder Urey, a schoolteacher and minister, died when the boy was six. His mother remarried and had two daughters in that marriage.

After high school, Urey taught in rural public schools from 1911 to 1914, first in Indiana and then in Montana. While teaching at a mining camp in Montana, Urey decided to attend the University of Montana in Missoula, where he majored in zoology with additional study in chemistry. After graduating in 1917, Urey worked as a chemist during World War I, an experience that set his future in chemistry. After the war, he returned to the University of Montana, where he taught chemistry for two years before beginning graduate study at the University of California at Berkeley. Under the direction of Gilbert N. Lewis, he received a doctorate for his dissertation on electron distribution in the energy levels of the hydrogen atom and thermodynamic calculations on gaseous molecules. Although the necessary molecular properties were not then available, Urey developed good approximate values. His work led to accepted methods for calculating thermodynamic properties from spectroscopic data. With an American-Scandinavian Fellowship, Urey spent 1923–24 with the Danish physicist Niels Bohr at the Institute for Theoretical Physics in Copenhagen. Afterward, Urey joined the faculty at Johns Hopkins University in Baltimore, Md., where he emphasized the importance of quantum mechanics for students of chemistry and directed his research toward the spectroscopic study of molecules. With the American physicist Arthur E. Ruark, he published Atoms, Molecules and Quanta (1930), an early discussion in English of the new field of quantum mechanics.

While visiting his mother in Seattle, Wash., in 1926, Urey met Frieda Daum, a bacteriologist from Lawrence, Kan. They married and had four children.

Deuterium And Atomic Bomb Research

In 1929 Urey moved to Columbia University in New York City, where he continued his work on the properties of molecules and atoms. The theory of isotopes—i.e., the idea that an individual element may consist of atoms with the same number of protons but with different masses—had been developed by the English chemist Frederick Soddy in 1913. The less-abundant isotopes of carbon, nitrogen, and oxygen had been discovered by others by the end of the 1920s, and Urey remarked that only the discovery of isotopes of hydrogen—the lightest element—could be more significant. Urey had a systematic chart of the isotopes, both known and predicted, on his office wall. This system included two additional isotopes of hydrogen—both undiscovered—one with twice the mass (2H) and one with three times the mass (3H) of ordinary hydrogen (1H). A letter to the editor from two physicists in the July 1, 1931, issue of Physical Review discussed some indirect evidence for the natural abundance of 2H—i.e., “heavy hydrogen” (which Urey later named deuterium) as one atom for every 4,500 atoms of 1H. Within days of reading this article, Urey devised an experiment to look for deuterium. After obtaining samples of hydrogen expected to be enriched in deuterium, he detected a spectrum that agreed with his predictions for deuterium from the Bohr atomic model. In 1934 Urey received the Nobel Prize, as well as the Willard Gibbs Medal from the Chicago Section of the American Chemical Society, for this discovery. Shortly after winning the Nobel Prize, Urey wrote the entry on deuterium for the 1936 printing of the 14th edition of the Encyclopædia Britannica.

Urey continued to investigate isotopes of hydrogen, carbon, oxygen, nitrogen, and sulfur. By 1939 he and his associates had developed successful methods for separating the rarer isotopes of all these elements, making them readily available for laboratory research. Urey wrote several papers on the separation of isotopes, including those of the heavy elements, and during World War II he was active in the U.S. government’s program for separating the fissionable uranium isotope 235U from the more-abundant 238U for use in the atomic bomb.

Urey served on various advisory committees for the Manhattan Project and directed efforts to separate the isotopes with several techniques, including gaseous diffusion. This was a huge and complex operation, beset by numerous problems in the development of a suitable diffusion barrier for the uranium hexafluoride. When the barrier that Urey had been working on was not chosen for the diffusion plant being built at Oak Ridge, Tenn., he gave up his work on diffusion. Although he remained nominal head of the project, he tried to convince U.S. President Harry S. Truman not to drop the bomb on Japan. After the war, Urey worked for civilian, rather than military, control of atomic weapons, and he proposed an international ban on their production and stockpiling.

Origin Of The Solar System

Two postwar events at the University of Chicago, where Urey became a professor in 1945, dramatically altered the focus of his research. The Face of the Moon (1949) by Ralph Baldwin, which presented scientific evidence that lunar craters were formed by asteroid and comet impacts and that the lunar mares were formed by lava flows, inspired an intense interest in the origin of the solar system that lasted for the rest of Urey’s life. His book The Planets: Their Origin and Development (1952) has been described as “the first systematic and detailed chronology of the origin of the Earth, Moon, the meteorites, and the solar system.” Initially, Urey rejected the hypothesis that the Moon and Earth had a common origin, believing instead that the Moon arose independently, was older than the Earth, and was only later captured by the Earth. Thus, Urey argued, the Moon should provide clues to the early solar system that the Earth could not. His ideas led to intense debates among scientists in the 1950s and ’60s, but he was ultimately able to influence the U.S. National Aeronautics and Space Administration (NASA) in undertaking the Apollo program of lunar exploration. After retiring from the University of Chicago in 1958, Urey became professor-at-large at the new campus of the University of California at San Diego. There he continued his research program in the planetary sciences. When Apollo 11 brought back rocks and dust from the Moon in 1969, Urey was one of the six scientists who first examined them. Later examinations of these rocks showed that his hypothesis about the Moon was wrong. Still the good scientist in his late 70s, however, Urey revised his thinking on the basis of the new evidence.

Legacy

Urey cared deeply about his fellow human beings, and he regarded the United States’ major problem as “the proper education and inspiration of our youth.” Politically active, he served as science advisor to the Democratic Party and to president-elect John F. Kennedy. He received the U.S. National Medal of Science in 1964. After retiring in 1970, Urey suffered from parkinsonism and cardiac disease.

Jai Ganesh · 2018-06-14 00:40:19

339) Sir David Brewster

Sir David Brewster, (born December 11, 1781, Jedburgh, Roxburghshire, Scotland—died February 10, 1868, Allerby, Melrose, Roxburghshire), Scottish physicist noted for his experimental work in optics and polarized light—i.e., light in which all waves lie in the same plane. When light strikes a reflective surface at a certain angle (called the polarizing angle), the reflected light becomes completely polarized. Brewster discovered a simple mathematical relationship between the polarizing angle and the refractive index of the reflective substance. This law is useful in determining the refractive index of materials that are opaque or available only in small samples.

Brewster was educated for the ministry at the University of Edinburgh, but his interest in science deflected him from pursuing this profession. In 1799 he began his investigations of light. His most important studies involved polarization, metallic reflection, and light absorption. He was elected a fellow of the Royal Society in 1815, and he invented the kaleidoscope the following year. He was knighted in 1831. In the early 1840s he improved the stereoscope by utilizing lenses to combine the two dissimilar binocular pictures and produce the three-dimensional effect. Brewster was instrumental in persuading the British to adopt the lightweight, flat Fresnel lens for use in lighthouses. In 1838 he became principal of the United College of St. Salvator and St. Leonard of the University of St. Andrews and in 1859 became principal of the University of Edinburgh.

Of Brewster’s numerous published works, his Treatise on Optics (1831) and Memoirs of the Life, Writings and Discoveries of Sir Isaac Newton (1855) are probably the most important.

Jai Ganesh · 2018-06-16 00:19:55

340) Heinrich Daniel Ruhmkorff

Heinrich Daniel Ruhmkorff, (born Jan. 15, 1803, Hannover, Hanover—died Dec. 20, 1877, Paris, France), German mechanic who invented the Ruhmkorff coil, a type of induction coil that could produce sparks more than 1 foot (30 centimetres) in length.

After apprenticeship to a German mechanic, Ruhmkorff worked in England with Joseph Brahmah, inventor of the hydraulic press. In 1855 he opened his own shop in Paris, which became widely known for the production of high-quality electrical apparatus. There he built a number of improved induction coils, including one that was awarded a 50,000-franc prize in 1858 by Emperor Napoleon III. Ruhmkorff’s coils consisted of a primary winding and a secondary winding in which a high voltage was produced. The coils were used for the operation of Geissler and Crookes tubes as well as for detonating devices. Ruhmkorff’s doubly wound induction coil later evolved into the alternating-current transformer.

Jai Ganesh · 2018-06-18 00:41:54

341) Hans Bethe

Hans Bethe, in full Hans Albrecht Bethe, (born July 2, 1906, Strassburg, Ger. [now Strasbourg, France]—died March 6, 2005, Ithaca, N.Y., U.S.), German-born American theoretical physicist who helped shape quantum physics and increased the understanding of the atomic processes responsible for the properties of matter and of the forces governing the structures of atomic nuclei. He received the Nobel Prize for Physics in 1967 for his work on the production of energy in stars. Moreover, he was a leader in emphasizing the social responsibility of science.

Education

Bethe started reading at age four and began writing at about the same age. His numerical and mathematical abilities also manifested themselves early. His mathematics teacher at the local gymnasium recognized his talents and encouraged him to continue studies in mathematics and the physical sciences. Bethe graduated from the gymnasium in the spring of 1924. After completing two years of studies at the University of Frankfurt, he was advised by one of his teachers to go to the University of Munich and study with Arnold Sommerfeld.

It was in Munich that Bethe discovered his exceptional proficiency in physics. Sommerfeld indicated to him that he was among the very best students who had studied with him, and these included Wolfgang Pauli and Werner Heisenberg. Bethe obtained a doctorate in 1928 with a thesis on electron diffraction in crystals. During 1930, as a Rockefeller Foundation fellow, Bethe spent a semester at the University of Cambridge under the aegis of Ralph Fowler and a semester at the University of Rome working with Enrico Fermi.

Early Work

Bethe’s craftsmanship was an amalgam of what he had learned from Sommerfeld and from Fermi, combining the best of both: the thoroughness and rigor of Sommerfeld and the clarity and simplicity of Fermi. This craftsmanship was displayed in full force in the many reviews that Bethe wrote. His two book-length reviews in the 1933 Handbuch der Physik—the first with Sommerfeld on solid-state physics and the second on the quantum theory of one- and two-electron systems—exhibited his remarkable powers of synthesis. Along with a review on nuclear physics in Reviews of Modern Physics (1936–37), these works were instant classics. All of Bethe’s reviews were syntheses of the fields under review, giving them coherence and unity while charting the paths to be taken in addressing new problems. They usually contained much new material that Bethe had worked out in their preparation.

In the fall of 1932, Bethe obtained an appointment at the University of Tübingen as an acting assistant professor of theoretical physics. In April 1933, after Adolf Hitler’s accession to power, he was dismissed because his maternal grandparents were Jews. Sommerfeld was able to help him by awarding him a fellowship for the summer of 1933, and he got William Lawrence Bragg to invite him to the University of Manchester, Eng., for the following academic year. Bethe then went to the University of Bristol for the 1934 fall semester before accepting a position at Cornell University, Ithaca, N.Y. He arrived at Cornell in February 1935, and he stayed there for the rest of his life.

Bethe came to the United States at a time when the American physics community was undergoing enormous growth. The Washington Conferences on Theoretical Physics were paradigmatic of the meetings organized to assimilate the insights quantum mechanics was giving to many fields, especially atomic and molecular physics and the emerging field of nuclear physics. Bethe attended the 1935 and 1937 Washington Conferences, but he agreed to participate in the 1938 conference on stellar energy generation only after repeated urgings by Edward Teller. As a result of what he learned at the latter conference, Bethe was able to give definitive answers to the problem of energy generation in stars. By stipulating and analyzing the nuclear reactions responsible for the phenomenon, he explained how stars could continue to burn for billions of years. His 1939 Physical Review paper on energy generation in stars created the field of nuclear astrophysics and led to his being awarded the Nobel Prize.

From Atomic Warrior To “Political Physicist”

During World War II Bethe first worked on problems in radar, spending a year at the Radiation Laboratory at the Massachusetts Institute of Technology. In 1943 he joined the Los Alamos Laboratory (now the Los Alamos National Laboratory) in New Mexico as the head of its theoretical division. He and the division were part of the Manhattan Project, and they made crucial contributions to the feasibility and design of the uranium and the plutonium atomic bombs. The years at Los Alamos changed his life.

In the aftermath of the development of these fission weapons, Bethe became deeply involved with investigating the feasibility of developing fusion bombs, hoping to prove that no terrestrial mechanism could accomplish the task. He believed their development to be immoral. When the Teller-Ulam mechanism for igniting a fusion reaction was advanced in 1951 and the possibility of a hydrogen bomb, or H-bomb, became a reality, Bethe helped to design it. He believed that the Soviets would likewise be able to build one and that only a balance of terror would prevent their use.

As a result of these activities, Bethe became deeply occupied with what he called “political physics,” the attempt to educate the public and politicians about the consequences of the existence of nuclear weapons. He became a relentless champion of nuclear arms control, writing many essays (collected in The Road from Los Alamos [1991]). He also became deeply committed to making peaceful applications of nuclear power economical and safe. Throughout his life, Bethe was a staunch advocate of nuclear power, defending it as an answer to the inevitable exhaustion of fossil fuels.

Bethe served on numerous advisory committees to the United States government, including the President’s Science Advisory Committee (PSAC). As a member of PSAC, he helped persuade President Dwight D. Eisenhower to commit the United States to ban atmospheric nuclear tests. (The Nuclear Test Ban Treaty, which banned atmospheric nuclear testing, was finally ratified in 1963.) In 1972 Bethe’s cogent and persuasive arguments helped prevent the deployment of antiballistic missile systems. He was influential in opposing President Ronald Reagan’s Strategic Defense Initiative, arguing that a space-based laser defense system could be easily countered and that it would lead to further arms escalation. By virtue of these activities, and his general comportment, Bethe became the science community’s conscience. It was indicative of Bethe’s constant grappling with moral issues that in 1995 he urged fellow scientists to collectively take a “Hippocratic oath” not to work on designing new nuclear weapons.

Throughout the political activism that marked his later life, Bethe never abandoned his scientific researches. Until well into his 90s, he made important contributions at the frontiers of physics and astrophysics. He helped elucidate the properties of neutrinos and explained the observed rate of neutrino emission by the Sun. With the American physicist Gerald Brown, he worked to understand why massive old stars can suddenly become supernovas.

Bethe wrote the entry on the neutron for the 14th edition of Encyclopædia Britannica.

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