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586 [911] WHITEHEAD HOPKINS
as occupying one liter at 4°C and this was supposed to have a volume of ex actly 1,000 cubic centimeters. In 1904 his new measurements showed, however, that a kilogram of water took up a vol ume of 1,000.028 cubic centimeters. Ever since chemists have carefully spo ken of milliliters rather than of cubic centimeters. Guillaume also searched assiduously for some cheap material out of which to construct standards of length and mass. The materials in use were platinum- iridium alloy, very expensive but useful because they did not corrode. In his search he discovered, in 1896, an alloy of iron and nickel, in the ratio of 9 to 5, which changed volume with temperature only very slightly. He gave this alloy the name invar, for “invariable,” because of its lack of change. Invar is of great value in the manufac ture of balance wheels and hair springs. The relative lack of change with temper ature meant watches and chronometers that kept time so much the better. It was another half century before scientists learned to divorce chronometry from these gross properties of matter, thanks to Townes [1400]. For the discovery of invar, Guillaume was awarded the 1920 Nobel Prize in physics.
[911] WHITEHEAD, Alfred North English mathematician and philos opher
15, 1861 Died: Cambridge, Massachusetts, December 30, 1947 Whitehead, the son of a clergyman- headmaster, graduated from Cambridge in 1884. For most of his life he taught mathematics in England, at Cambridge till 1911, then at the University of Lon don; but in 1924 he went to the United States as professor of philosophy at Har vard University, remaining in the coun try the rest of his life. He was intensely interested in the logi cal basis of mathematics. From 1910 to 1913, in collaboration with Bertrand Russell [1005], he published the three- volume work Principia Mathematica in which mathematics was built up out of symbolic logic on what seemed to be a definitive way at last. However, owing to the later work of Godel [1301], it would seem that the adjective “definitive” can never be applied to any system of mathe matics. [912] HOPKINS, Sir Frederick Gowland English biochemist Born: Eastbourne Sussex, June 30, 1861 Died: Cambridge, May 16, 1947 After an unhappy childhood and youth, Hopkins spent time uncertainly in insurance, analytical chemistry, and a few other miscellaneous activities. In 1888, however, he took advantage of a small inheritance and aimed for medi cine. He obtained his doctoral degree and began teaching, in 1894, at Guy’s Hospital in London. He then entered the field of biochemical research. In the late nineteenth century, it was known that gelatin, although a protein, would not support life if it was the sole protein in a rat’s diet. In 1900 Hopkins discovered tryptophan, one of the amino acid building blocks of proteins, and showed that it was missing in gelatin. This made it clear that some of the amino acids could not be manufactured in the body and had to be present as such in the diet. He thus originated the concept of the “essential amino acid,” which Rose [1114] was to bring to a cli max a generation later. Hopkins then found that of two sam ples of apparently identical protein, one might support life and one might not. This to him meant that one might con tain some substance essential to the body only in traces. In 1906 he made this point in a lecture, saying that rickets and scurvy might be brought about by lack of such necessary trace substances. Eijk- man [888] had already done his work on beriberi, and that too could be inter preted in the light of Hopkins’s sugges tion.
In 1905 he was elected to the Royal 587 [913] BATESON
NANSEN [914] Society and in 1914 appointed professor of biochemistry at Cambridge. (It was a new department.) Nor did his labors cease, for in 1921 he isolated the impor tant substance glutathione from living tissue and showed its role in oxidative processes within cells. In 1925 he was knighted, and in 1929 he shared the Nobel Prize in medicine and physiology with Eijkman for his enunciation of what later came to be known as the “vitamin concept.” From 1930 to 1935 he served as president of the Royal Society. [913] BATESON, William English biologist
8, 1861
Died: Merton, Surrey, February 8, 1926
Bateson obtained his master’s degree from Cambridge, where his father held an important position. His first impor tant investigations dealt with Balano- glossus, a wormlike creature, with a lar val stage resembling that of echino- derms, such as starfish. (In fact, Jo hannes Müller [522] had classified the Balanoglossus larva as an echinoderm.) Bateson showed that Balanoglossus pos sessed in addition to gill slits, a scrap of a notochord and a dorsal nerve chord. This established the creature as a chor date, the phylum introduced by Kovalev- ski [750] and Balfour [823] that includes the vertebrates and, therefore, man. This was the first indication that chordates were offshoots of a primitive echinoderm stock, a theory now widely accepted. Bateson was a strong supporter of Mendelian views after Mendel’s [638] papers had been rediscovered by De Vries [792]. It was Bateson who trans lated Mendel’s papers into English. In 1905 experiments he conducted on Men delian inheritance showed that not all characteristics are independently in herited. Some characteristics are in herited together and this gene linkage was eventually explained by Morgan [957] (though Bateson proved reluctant to accept Morgan’s theories when these were first advanced). About the same time, Bateson pro posed that the study of the mechanism of inheritance be termed genetics and thus he added a key term to the vocabu lary of science. Bateson, in 1908, was the first ever to hold a professorial position (at Cam bridge) in this new field of genetics. [914] NANSEN, Fridtjof (nahn'sen) Norwegian explorer
October 10, 1861 Died: Lysaker (near Oslo), May 13, 1930 Nansen studied zoology at the Univer sity of Christiania (Oslo) but gained fame as an explorer. In 1882 he was serving on a sealing ship and, in Green land waters, could see the ice cap from a distance. It occurred to him that the ice cap could be crossed. In 1888 he and five others landed on the eastern shore of Greenland and managed to cross it to the inhabited western shore in a six-week trek. It was the first time Greenland had ever been crossed by land. He then planned to cross the Arctic Ocean by designing a ship that would be lifted, rather than crushed, when the ocean about it froze. His idea was to have the ship (and himself and crew) carried along by the drifting sea ice of the Arctic Ocean to a spot near the North Pole. His ship Fram (“Forward”), with thirteen men aboard, set sail in 1893. It was frozen in and drifted. On March 14, 1895, Nansen left the frozen-in ship and trekked farther northward by dogsled, reaching 86° 14' (on April 8) before turning back. It was the most northerly attitude ever reached by human beings up to that point. Nansen got back to Norway, with his ship, in 1896 after a three-year voyage. After World War I, Nansen interested himself in humanitarian work, in caring for prisoners of war, for those suffering in famines, for the displaced and perse cuted. His work in this direction eclipsed 588 [915] INNES
WIECHERT [917] even his towering fame as an explorer, and in 1922 he was awarded the Nobel Peace Prize. [915] INNES, Robert Thorbum Ayton (in'is)
Scottish astronomer Born: Edinburgh, November 10, 1861
Died: Surbiton, England, March 13, 1933 Innes left school at twelve and was en tirely self-taught thereafter. He emi grated to Australia in 1884 and was a merchant there, doing well. His work as an amateur in astronomy was sufficiently notable, however, for him to be offered a post at the Cape Observatory in South Africa by Gill [763]. While there, Innes specialized in scour ing the southern skies for binary stars, discovered 1,628 hitherto unknown ex amples of this class. His best-known dis covery came in 1915, however, when he discovered a faint star near Alpha Cen- tauri, which seems to be a third and dis tant companion of that binary. At its present position in its mighty orbit about that star, it happens to be a little closer to us than its companions are, so that it is the nearest individual star to us (always excluding our own sun). It is often called Proxima Centauri for that reason, “proxima” meaning, in Latin, “nearest.” [916] KENNELLY, Arthur Edwin British-American electrical engi neer
Born: Bombay, India, December 17, 1861 Died: Boston, Massachusetts, June 18, 1939 Kennelly, the son of an Irish lawyer, was educated in London and did not at tend a university. He grew interested in the expanding field of electricity and be came a telegraph operator in his teens, as Edison [788] had been a couple of decades before. At the age of twenty-six Kennelly went to the United States and worked as an assistant to Edison until 1894, when he went into business for himself as a consulting engineer. Like Heaviside [806] and Steinmetz [944], his importance to the development of electricity was not so much in the construction of novel devices making use of electrical circuits, as in the application of advanced mathematics to the under standing of the behavior of such circuits. He is best known, however, for a sug gestion he made in 1902 arising out of the fact that the wireless messages of Marconi [1025] had reached from En gland to Newfoundland, working their way around the bulge of the earth. The radio waves ought to have moved in a straight line, as light waves do, and have been unable to travel past the horizon. That radio waves did travel beyond the horizon made it seem to Kennelly that somewhere in the upper atmosphere was a layer of electrically charged particles that, his theories told him, could reflect radio waves. Thus, Marconi’s message crossed the Atlantic Ocean by bouncing off the upper atmosphere. This speculation, a more sophisticated version of something Stewart [678] had suggested twenty years earlier, was inde pendently published some months later by Heaviside and was eventually shown to be founded in fact by Appleton [1158].
In 1902 he was appointed professor of engineering at Harvard and remained there till his retirement in 1930. [917] WIECHERT, Emil (veeTchert) German seismologist
Sovetsk, USSR), December 26, 1861
Wiechert, the son of a merchant, stud ied physics at Königsberg University, graduated in 1889, and began lecturing there the following year. In 1897 he moved to Göttingen and established a department of geophysics. At that time, earthquakes were being studied in detail at last, thanks to the work of John Milne [814], but the seis 589 [918] HILBERT
GULLSTRAND [919] mographs in use were rather primitive. In 1900 he produced an “inverted- pendulum” seismograph, which is essen tially what has been used ever since. It was this seismograph that produced rec ords sufficiently accurate to allow some idea of the detailed inner structure of the earth to be worked out. Wiechert suggested the presence of a dense core, for instance, something Beno Gutenberg [1133] was soon to demonstrate convinc ingly. [918] HILBERT, David German mathematician Born: Königsberg, East Prussia (now Kaliningrad, USSR), January 23, 1862
1943
Throughout the nineteenth century, particularly after the discovery of non Euclidean geometries by Lobachevski [484], Bolyai [530], and Riemann [670], mathematicians inspected Euclid’s [40] system of axioms closely. It became more and more plain that Euclid did not really start with basic self-evident con cepts and actually assumed a great many things in addition without specifically saying so. Attempts were made to establish a minimum number of unidentified terms and basic definitions, and from these to deduce rigorously the entire structure of mathematics. This is the science of axi- omatics, and it was Hilbert and Peano [889] who finally established it. Hilbert, the son of a judge, obtained his Ph.D. at the University of Königs berg in 1885, and in 1899 he published a book Foundations of Geometry in which the first really satisfactory set of axioms for geometry was set forth. He began with points, lines, and planes as undefined concepts. Euclid had tried to define them, without, however, actually doing so. Euclid’s definitions had only seemed satisfactory because his readers already had an intuitive knowledge of what it was he was trying to define. Hilbert was content not to define them but merely to describe certain properties of these objects. Provided they possessed those properties, the formal definition did not matter. He also used certain rela tionships as “between,” “parallel,” and “continuous” without defining them. Again, provided the consequences of using those words were clearly set forth, it didn’t matter what they actually meant. Hilbert also proved his system of axioms to be self-consistent, something the Greeks had assumed concerning the Euclidean axioms (and correctly) but had not formally proved. Thus, Euclid’s work was finally com pleted. It was not changed in essence, but its foundation was shifted from intu ition to logic. Hilbert’s system of axioms is not the only one possible, but that does not mat ter. Axioms are no longer considered self-evident truths, but merely self consistent starting points from which a mathematical structure can be devel oped. This structure is independent of “reality” (whatever that is), but to be useful it must have some analogy to what seems to us to be the “real world.” Hilbert became professor of mathe matics at Gottingen in 1895 and held the post till his retirement in 1930. In 1925, he fell ill with pernicious ane mia, then thought to be incurable. At just that time, however, Minot [1103] was working out the appropriate treat ment and Hilbert had eighteen more years of life. [919] GULLSTRAND, Allvar (gul'strand) Swedish physician Born: Landskrona, Malmohus, June 5, 1862 Died: Uppsala, July 21, 1930 Gullstrand, the son of a physician, studied at Uppsala, Vienna, and Stock holm and received his license to practice medicine in 1888. He was an ophthalmologist, who stud ied the physics of the eye in the greatest detail, carrying matters far beyond Helm holtz [631]. His studies on astigmatism, for instance, made it possible to design corrections more efficiently. He designed 5 9 0
[920] LENARD
LENARD [920] lenses to improve the vision of eyes from which lenses had been removed because of cataract. He also designed devices for locating foreign bodies in the eye. For his work on the eye, he received the 1911 Nobel Prize for medicine and physiology. [920] LENARD, Philipp Eduard Anton von (lay'nahrt) Hungarian-German physicist
(now Bratislava, Czechoslovakia), June 7, 1862
temberg, May 20, 1947 Lenard, the son of a wealthy wine maker, studied under Bunsen [565] and Helmholtz [631], obtaining his doctor’s degree summa cum laude at the Univer sity of Heidelberg in 1886. After filling a variety of posts including that of assis tant to H. R. Hertz [873] in 1893, he re turned to Heidelberg in 1907 as profes sor of theoretical physics, a position he held until his retirement in 1931. When he was a teenager, Lenard read a paper by Crookes [695] on the subject and became interested in cathode rays, the radiation emitted from the negative electrode in a vacuum, under the influence of a high electric potential. Hertz had discovered that cathode rays could penetrate thin layers of metal and Lenard, who was then his assistant, de vised a cathode-ray tube in 1892 with a thin aluminum window through which the cathode rays could emerge into the open air. (Such open-air cathode rays were called Lenard rays for a time.) Lenard studied the properties of these rays carefully, measuring their absorp tion by different materials, and how they ionized air, making it electrically con ducting. For these investigations he re ceived the 1905 Nobel Prize in physics. Beginning in 1902 he studied the pho toelectric effect, work which also dates back to Hertz, the first to observe it. Lenard showed that the electrical effects produced by light falling upon certain metals was the result of the emission by those metals of electrons. The emission of electrons by way of the photoelectric effect, more than anything else, per suaded scientists that atoms contained electrons as part of their structure. Fur thermore, since all substances showing the effect gave off identical electrons, it seemed that different atoms might have very similar internal structures. He also showed that only certain wavelengths of light could bring about electron emission and that, for any par ticular wavelength, electrons of fixed en ergies were given off. Increasing the in tensity of the light would increase the number of electrons but not their indi vidual energy. His explanations for this were the first to assume that an atom was largely empty space, an assumption that was to be definitely established a few years later by Ernest Rutherford [996]. Lenard believed that electrons and analogous positively charged particles were evenly distributed through the atom. He did not foresee the nuclear atom which Rutherford was to make fa mous. It was Einstein [1064] who, in 1905, explained the photoelectric effect, neatly and finally, by the application of the quantum theory of Planck [887], During World War I, Lenard was caught up in a supernationalism that afflicted a number of scientists at the time, but it was something from which he, unlike many others, never recovered. In fact, it grew only the more extreme and paranoid with Germany’s defeat. Lenard was openly anti-Semitic and wholeheartedly supported the Nazi doc trines, one of only two important scien tists (the other being Stark [1024]) to do so. He heatedly denounced “Jewish sci ence,” forgetting his debt to Hertz, who was of Jewish descent. He also de nounced Einstein and the theory of rela tivity on purely racial grounds, for he advanced no scientific arguments of merit. His own lack of mathematical ability turned Lenard the more bitterly against the great mathematical theories of relativity and quantum mechanics. He knew Hitler personally and coached him on the racial interpretation of physics. Most nuclear theory was pic tured by Lenard as mere Jewish perver Download 17.33 Mb. Do'stlaringiz bilan baham: 
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