Biographical encyclopedia
Download 17.33 Mb. Pdf ko'rish
|
|
571 [887] PLANCK
PLANCK [887] when Max was nine years old and he ob tained his first education there. In his college days he transferred from Munich to Berlin and there, as was true of Hertz [873], studied under Helmholtz [631], Clausius [633], and Kirchhoff [648], re ceiving his doctorate summa cum laude in 1879 (suffering a two-year delay be cause of illness). In 1880 he joined the faculty at Mu nich and five years later received a pro fessorial appointment at Kiel University. In 1889 he replaced Kirchhoff, who had died, at the University of Berlin. He remained there until his retirement in 1926. Planck’s doctoral work was on ther modynamics because of his interest in the works of Clausius. He claimed that Helmholtz did not read his dissertation at all and that though Kirchhoff read it, he disapproved. Clausius himself was not interested. And, indeed, Planck’s doc toral work was of minor importance and was perhaps worth no more than these great men indicated by their lack of in terest. In time, however, Helmholtz grew to appreciate Planck and was instru mental in getting him his Berlin appoint ment. In Berlin, Planck turned to the prob lem, first raised by his old teacher, Kirchhoff, of the black body, one that absorbs all frequencies of light and therefore, when heated, should radiate all frequencies of light. But now comes a delicate point. The number of different frequencies in the high-frequency range is greater than the number in the low-frequency range; just as the number of integers higher than a million is greater than the number of in tegers lower than a million. If a black body radiated all frequencies of elec tromagnetic radiation equally, then vir tually all the energy would be radiated in the high-frequency region; just as, if you were asked to pick any number at all you would be almost certain to pick a number over a million because there are so many more numbers to choose from in that region. This situation, with regard to radiation, is referred to as the “violet catastrophe” because the highest fre quency radiation in the visible light spec trum is the violet. In actuality, this does not happen; there is no violet catastrophe and the physical theory of the 1890s could not explain why. Both Wien [934] and Ray leigh [760] tried to work out equations describing how the radiation of the black body was distributed in actual fact. Wien’s equation worked pretty well at high frequencies but not at low. Ray leigh’s equation worked at low frequen cies but not at high. In 1900 Planck managed to work out a relatively simple equation that de scribed the distribution of radiation ac curately over the entire stretch of fre quency. His equation was based on a crucial assumption: energy is not infi nitely subdivisible. Like matter, it existed in “particles.” These particles Planck called quanta (from Latin, meaning “how much?”) or, in the singular, quan tum. He further supposed that the size of the quantum for any particular form of electromagnetic radiation was in direct proportion to its frequency. Thus, the vi olet light at one extreme of the visible spectrum has twice the frequency of the red light at the other extreme. A quan tum of that violet light would therefore contain twice the energy of a quantum of red light. Now then, suppose energy can only be absorbed or emitted in whole quanta. Therefore, when a black body radiates, it is not likely to radiate all wavelengths equally. To radiate low frequency is easy, for only a small quantity of energy must be brought together to form a quantum of low-frequency radiation. However, to radiate higher-frequency ra- ' diation requires more energy and it is less probable that the additional energy can be gathered together. The higher the frequency the less probable the radia tion. Thus, a body at 600°C radiates mostly in the small-quantum infrared with just enough in the visible red to give it a glow. There is no violet catas trophe because although the high fre quencies are many, their quantum- energy requirements make their radia tion improbable. 572 [887] PLANCK
EIJKMAN [888] As temperature goes up, the supply of energy is heightened and it becomes more and more probable that higher en ergy quanta can be radiated. For that reason, as an object heats up, the light radiated turns orange, yellow, and even tually bluish. In this way Wien’s law, worked out by observation only, was given a theoretical basis. The small constant that is the ratio of the frequency of the radiation and the size of the quantum is called Planck’s constant and it is symbolized as h. It is now recognized as one of the funda mental constants of the universe. This theory was so revolutionary that it was not accepted by physicists at once and, in fact, Planck himself did not quite believe it but half-suspected it might be only a piece of mathematical jugglery without any correspondence to anything real in nature. He struggled for years to find a way around his own dis covery and would not accept statistical interpretations of thermodynamics intro duced by Boltzmann [769], In 1905 Einstein [1064] first applied the quantum theory to an observable phenomenon that could not be explained by nineteenth-century physics—to the photoelectric effect first noted by Hertz. Planck would not quite believe that ei ther, although he readily accepted Ein stein’s theory of relativity. Then, in 1913 Bohr [1101] incorpo rated the quantum theory into the struc ture of the atom and explained a great deal that nineteenth-century physics could not. In fact, all of physics before 1900 is now called classical physics and after 1900 it is modem physics. The wa tershed is the quantum theory. Modern physics could not exist without new forms of mathematical analysis involving quanta, this being referred to as quan tum mechanics. In 1918 the importance of the quan tum theory had reached the point where Planck received the Nobel Prize in phys ics. Einstein and Bohr, for the use they made of it, received the prize a very few years later. The joy of the Nobel Prize must have been tempered for Planck by the death of a son in action in World War I and the loss, at this same period, of his two daughters in childbirth. In 1930 Max Planck became president of the Kaiser Wilhelm Society of Berlin, and it was renamed the Max Planck So ciety. His old age saw his renown in the world of science second only to that of Einstein. Nor was he too old to resist Hitler firmly in the days of Nazi ascen dancy. He conceived it his duty to re main in Germany but at no time did he lend his voice and prestige to the Hitler regime in any way. He interceded per sonally (but unsuccessfully) with Hitler on behalf of his Jewish colleagues and was forced to resign his presidency of the Max Planck Society in 1937 in con sequence. World War II was disastrous for him. His house was destroyed by Allied bombings and his son Erwin was exe cuted in 1944, accused of taking part in the plot against Hitler’s life. Planck lived into his ninetieth year, however, surviving World War II and living to see Nazism destroyed. He was rescued by American forces in 1945, while in flight during the last days of confusion before Germany’s final defeat. He was renamed president of the Max Planck Society until a successor could be found. He was returned to Gottingen and there spent his last two years, hon ored and respected. [888] EIJKMAN, Christiaan (ike'mahn) Dutch physician Born: Nijkerk, August 11, 1858 Died: Utrecht, November 5, 1930 Eijkman, the son of a schoolmaster, obtained his medical degree at the Uni versity of Amsterdam in 1883, then went to Germany to study under Koch [767]. At first he had been interested in physi ology, but after a short stay in the army in the Dutch East Indies he grew inter ested in bacteriology and began to work in that field after having been invalided home. In 1886, when he was strong enough to return to the East Indies, it was as part of a medical team sent to study the disease beriberi. Koch had been asked to tackle this particular dis
[888] EIJKMAN
PEANO [889] ease but the press of work forced him to refuse the project and he suggested his former pupil Eijkman for the task. Pasteur’s [642] germ theory of disease was, at the time, leading to victory after victory at the hands of such physicians as Koch and Behring [846]. In the 1880s it almost seemed natural to think that all diseases were caused by microorganisms. Consequently, the organism that was re sponsible for beriberi was sought but in vain. Most of the group returned home with nothing accomplished, but Eijkman remained behind in Batavia (the modem Djakarta) as director of a new bacteri ological laboratory medical school for native doctors. In 1896 he solved the problem of beriberi, partly by accident. A disease broke out among the chickens being used at the laboratory for bacteriological researches. It showed symptoms similar to beriberi. Eijkman pounced upon those chickens, trying to find the germ causing it, trying to transfer the disease from a sick chicken to a healthy one. He failed in both at tempts. Then, as suddenly as it had ap peared, the disease vanished, and nothing was left on which to experiment. Eijkman investigated in other direc tions and found that for a certain period one of the cooks had been using rice from the hospital stores to feed the chickens. The cook was transferred and the succeeding functionary did not think it right to use rice meant for hospital pa tients on chickens. He went back to commercial chicken feed. The chickens had developed the disease only when they were on the rice. Eijkman found that he could produce the disease at will by feeding the chickens polished rice of highest quality. By feeding them on unpolished rice, he cured it. Eijkman was thus the first to pinpoint what we now call a “dietary- deficiency disease,” that is, a disease caused by the absence from the diet of some essential component that need be present only in traces to prevent the dis ease.
Eijkman did not appreciate the true meaning of his findings at first. He thought that there was a toxin of some sort in rice grains which was neutralized by something else in the hulls. In the course of the next decade, however, sev eral people suggested the correct expla nation, the most prominent being Hop kins [912]. The missing trace component then received the name “vitamine” from Funk [1093], the word losing its final “e” and becoming “vitamin” a few years later. Thus, with the turning of the century it was shown that the germ theory of dis ease, admirable though it was, did not offer a universal explanation for all dis orders. There were some diseases that were purely biochemical. About the same time as the concept of a dietary- deficiency disease developed, the re searches of Starling [954] and Bayliss [902] opened the way to the under standing of still another variety of bio chemical disorder. Shortly after his triumph, Eijkman was ill again and returned to the Netherlands for good, becoming professor of hygiene at the University of Utrecht. In 1929, with the significance of his finding fully realized, he shared the Nobel Prize in medicine and physiology with Hopkins, though he was by then too ill to travel to Stockholm to accept the prize in person. [889] PEANO, Giuseppe (pay-ah'noh) Italian mathematician Born: Cuneo, Piedmont, August 27, 1858 Died: Turin, April 20, 1932 Peano’s uncle was a priest and lawyer who took charge of the boy when he was twelve and saw to his education. In 1876 Peano entered the University of Turin and graduated with high honors in 1880. He gained a professorial appointment at Turin in 1890. Peano labored to develop the system of symbolic logic beyond the beginnings of Boole [595], In 1889 he published A
logic to the fundamentals of mathe matics, a work Whitehead [911] was to carry further a quarter century later. 574 [890] AUER
AUER [890] Peano built up a system of axioms begin ning with undefined concepts for “zero,” “number,” and “successor.” In 1890 he accepted a professorship in mathematics at the University of Turin. Peano stepped out of mathematics in 1903 in order to invent what he hoped would be an international language (for speakers of the West European lan guages at any rate) by adopting a form of what might almost be called pig Latin. It made use of Latin stems with out inflections, throwing in words from German and English where these seemed advisable. The result is “Interlingua,” which can be read without trouble by anyone speaking a Romance language and with out too much trouble by those who speak Teutonic languages provided they are not completely unfamiliar with the Romance languages. Some scientific journals now publish summaries of the papers they contain in Interlingua as a device for reaching as many people as possible with a minimum of translation. [890] AUER, Karl, Baron von Welsbach (ow'er) Austrian chemist Born: Vienna, September 1, 1858 Died: Welsbach Castle, Carinthia, August 8, 1929 Auer was the son of the director of the Imperial Printing Press in Vienna and had a good education. For his col lege training he traveled to Heidelberg and studied under Bunsen [565]. There he grew interested in rare earths, particu larly in the supposed element didymium, discovered a generation earlier by Mo sander [501]. In 1885, after much care ful work, he managed to show that didymium (derived from the Greek word for “twin”) was twins in actual fact. He isolated the oxides of two sepa rate rare earth elements from didymium, and these he named praseodymium (“green twin,” from the color of a prominent spectral line) and neodymium (“new twin”). Auer was the first to find practical uses for the rare earth elements. It oc curred to him that gas flames might be made to give more light if they were al lowed to heat up some compound that would itself then glow brightly. He tried many substances that would glow at high heat without melting and finally found that if he impregnated a cylindrical fabric with thorium nitrate to which a small percentage of cerium ni trate (a compound of one of the rare earth elements) was added, he could ob tain a brilliant white glow in a gas flame. This “Welsbach mantle” was patented in 1885. It would have greatly improved city lighting had not Edison’s [788] elec tric light done far better and outmoded all forms of gas lighting. The mantle is still used in kerosene lamps and in other limited ways. Auer, however, improved on Edison’s lights in one respect. In 1898 he was the first to introduce a metallic filament in place of Edison’s carbonized thread. Auer used the rare metal osmium for the purpose. The metallic filament was longer lasting than the carbon, but os mium, a member of the platinum group, was far too rare to be really useful. However, Auer had pointed the way to ward Langmuir’s [1072] tungsten fila ments a decade later. Auer’s interest in lighting (he chose as his baronial motto, “more light”) led him to another discovery related to his beloved rare earth elements. He found that a metallic mixture of these elements (appropriately called “Mischmetal” and consisting chiefly of cerium), when mixed with some iron, was strongly pyrophoric; that is, on being struck, it yielded hot sparks. These sparks could be used to light gas jets and could even be made to allow automatic lighting. In this respect, Auer was the first to im prove on the prehistoric invention of flint and steel. The most common use of Mischmetal now is as flints in cigarette lighters. In 1901 Auer was raised to the heredi tary nobility by Francis Joseph I of Aus tria and was made Freiherr (Baron) von Welsbach. 575 [891] PUPIN
HADFIELD [892] [891] PUPIN, Michael Idvorsky (poo'- peen [Serbian]; pyoo-peen' [En glish])
Yugoslavian-American physicist Born: Idvor, Austria-Hungary (now part of Yugoslavia), October 4, 1858
March 12, 1935 Pupin, the son of illiterate peasants, was encouraged by them to obtain an ed ucation. He spent more than a year in Prague, but then went to the United States, arriving there in 1874 as an abso lutely penniless, fifteen-year-old immi grant. Working his way upward at any thing he could turn his hand to, he finally managed to attend Columbia Uni versity, graduating in 1883. He had intended a general education in the liberal arts, but a book of Tyn dall’s [626] popular essays on science fired his interest. He went on to obtain his doctorate in Germany under Helm holtz [631], studying also under Kirchhoff [648]. He returned to the United States to join the faculty of Co lumbia University in 1890. His inventions were numerous. He de vised a fluorescent screen that would react to the impingements of X rays, which could then be observed directly and photographed more easily (a fluoro- scope). He also devised a method whereby signals could be transmitted across thin wires over long distances without distortion by loading the line with inductance coils at intervals, these serving to reinforce the signals. This was in accord with a suggestion made earlier by Heaviside [806], The Bell Telephone Company bought the device in 1901 and it made long-distance telephony practi cal. During World War I, Pupin partici pated actively in the war effort of Serbia, whose quarrel with Austria-Hungary had precipitated the war. At the final peace treaty the section of Austria-Hungary in which Pupin had been born was joined to Serbia to form the greatly enlarged nation of Yugoslavia. After the war he wrote his autobi ography, From Immigrant to Inventor, which won the Pulitzer Prize in 1924. [892] HADFIELD, Sir Robert Abbott British metallurgist Born: Sheffield, Yorkshire, November 28, 1858 Died: London, September 30, 1940
Sheffield was a great iron and steel center and Hadfield, born the son of a steel manufacturer, early interested him self in the problem of improving steel. He took over the family firm in 1882 when ill health forced his father’s retire ment. Adding manganese seemed to make steel brittle, but Hadfield tried adding more manganese than previous metal lurgists had thought advisable. By the time the steel was 12 percent manganese it was no longer brittle. If it was then heated to 1000°C and quenched in water, it became super-hard and could be used for rock-breaking machinery and for metal working. Where ordinary steel used for railroad rails had to be replaced every nine months, manganese-steel rails lasted twenty-two years. It was also used for steel helmets in World War I. Hadfield patented his manganese-steel in 1883 and that marks the beginning of the triumph of “alloy steel.” Other metals were added to steel—chromium, tungsten, molybdenum, vanadium—in search of new alloys with new and useful properties. By 1913 even a nonrusting “stainless steel” (containing chromium and nickel) had come into use after one experi menter had noticed that a scrap pile con taining alloy specimens that had been discarded as worthless included some pieces that had remained bright and shiny after a long period in the open. Similarly Honda [985] devised new mag netic alloys. Steel can now do innumer able jobs that it couldn’t do in Bes semer’s [575] time. Hadfield was knighted in 1908 and made a baronet in 1917.
During World War I, Hadfield and his wife established a hospital in France. 5 7 6
|
