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261 [393] FOURIER
FOURIER [393] carrying through the tedious computa tions necessary for his Mécanique céleste. Computations became his whole life. He observed eight new comets and cal culated their orbits, but the climax of his life came with his attempt to calculate the orbit of the newly discovered planet Uranus. In 1821 he made use of not only the observed positions since Herschel’s [321] discovery in 1781, but all the earlier po sitions noted before the “star” was recog nized to be a planet. He found to his dis may that the orbit he calculated from the observations after 1781 did not quite fit the prediscovery observations, so he was forced to ignore the latter. However, the orbit he calculated from the postdis covery observations did not suit either. Uranus began to drift away from it. Something was wrong and for twenty years, astronomers labored and puzzled over the discrepancy until Adams [615] and Leverrier [564] solved the problem with the discovery of a new planet, which Bouvard died three years too soon to see.
[393] FOURIER, Jean Baptiste Joseph, Baron (foor-yayO French mathematician
1768
Died: Paris, May 16, 1830 Fourier was an orphan by the age of eight. As a youth he was headed for the priesthood, rather against his will. He wanted to be in the army, but as the son of a tailor he could serve only as cannon fodder in the ranks. And then came the French Revolution. Fourier set his heart on becoming an artillery officer, so he could use the mathematics in which he was interested —much as did another man, Napoleon Bonaparte, who was bom a few months after Fourier. Fourier did not have Bo naparte’s success, however, for he showed too much ability at mathematics. He tried to play a moderate role in the French Revolution and came close to the guillotine, but the fall of Robespierre saved him. A while later he was arrested by the conservatives who succeeded Robespierre, and who accused Fourier of being pro-radical. Again he was released. After his graduation from military school he was offered a professorship by the school in 1795 and accepted it. Nevertheless his career remained linked with Napoleon’s. He accompanied Napoleon to Egypt in 1798 and was gov ernor of a portion of it during the French occupation, using the opportu nity to explore the upper Nile. In 1808, after he had made his great mathe matical discoveries, he was made a baron by Napoleon. He survived Napoleon’s downfall to receive new honors under . the restored Bourbons. In 1822 he be came joint secretary of the Academy of Sciences, along with Cuvier [396], After Fourier returned to France from Egypt in 1801, he was charged with or ganizing the accumulated mass of data gathered in Egypt and of arranging its publication. This he did, and thereafter busied himself with science (his adven ture in military affairs in Egypt had not been a happy one and he had had enough). The problem that interested him chiefly was the manner in which heat flowed from one point to another through a particular object. This de pended on the temperature difference be tween the two points, the heat conduc tivity of the material making up the ob ject, the shape of the object, and so on. The matter was quite complex. Fourier summoned all his mathe matical ingenuity and discovered what is now called Fourier’s theorem. This states that any periodic oscillation (that is, any variation which, sooner or later, repeats itself exactly, over and over), however complex, can be broken up into a series of simple regular wave motions, the sum of which will be the original complex pe riodic variation. It can be expressed, in other words, as a mathematical series in which the terms are made up of trig onometric functions. It was the an nouncement of this in 1807 that brought Fourier scientific fame and earned him his baron’s title. When Napoleon re turned to France in 1815, after his first abdication and exile to Elba, Fourier re- 262 [394] NICOL
SMITH [395] joined him. After Napoleon’s second fall at Waterloo, Fourier was consequently out of favor in France for a while. It was not until 1822 that Fourier, using his theorem, completed his work on the flow of heat in a book entitled
spired Ohm [461] to similar thoughts on the flow of electricity. In this book Fourier was the first to make clear the point that a scientific equation must in volve a consistent set of units. Thus began dimensional analysis. Fourier’s theorem has a very broad value. It can be used in the study of sound and of light and, indeed, of any wave phenomenon. The mathematical treatment of such phenomena, based on Fourier’s theorem, is called harmonic analysis. Even great scientists can have their ir rational beliefs. Fourier believed heat to be essential to health so he always kept his dwelling place overheated and swathed himself in layer upon layer of clothes. He died of a fall down the stairs. [394] NICOL, William Scottish physicist Bom: Scotland, 1768 Died: Edinburgh, September 2, 1851
In 1828 Nicol, who lectured at the University of Edinburgh, made use of the phenomenon of double refraction discovered by Bartholin [210] to produce a single beam of what is now called polarized light. He did this by placing two crystals of Iceland spar together and cementing them with Canadian balsam. Light entering the first half of the crystal was refracted into two rays. One of them was reflected out of the crystal altogether at the layer of balsam. The other, striking the balsam at a slightly different angle, passed through. This beam could also pass through a second “Nicol prism” if the second prism was lined up parallel to the first. If the sec ond prism was then rotated, less and less of the light would pass through until, when the second prism was at right an gles to the first, none of the light got through. When a solution of organic sub stance was placed between the prisms, the second prism had to be placed at a certain angle (sometimes) to allow all the light to pass through it. This angle represented the degree of the twisting of polarized light that Biot [404] had first observed. The Nicol prism made it easy to observe this twisting and opened up the technique of polarimetry, which was to have great consequences in connec tion with theories of molecular structure. Also notable was Nicol’s development of methods for preparing thin slices of minerals and of fossil wood in order to make microscopic studies feasible. [395] SMITH, William English geologist
March 23, 1769 Died: Northampton, August 28, 1839
Smith’s father, a village blacksmith, died when the child was but eight. In consequence, young Smith got nothing but the barest of a grammar school edu cation. He began his career when, in 1787, a surveyor came to town to do a job and needed a bright young man to help him. Smith eagerly applied and did so well that the surveyor took him into the busi ness. It was the era when England was lac ing the countryside with canals, and Smith had to do with laying routes for them. Observing the earth in cross sec tion at excavation sites, he was impressed by the way rocks of different types and forms were arranged in paral lel layers, or strata. In 1793 he was put in charge of sur veying the Somerset coal canal and he toured England to observe other canals. This further increased his interest in and knowledge of strata, and his friends took to calling him Strata Smith. By 1799 he was writing on the subject, but did not publish for a number of years. Others had observed strata before him, but Smith was making a new point. Each stratum had its own characteristic 263 [396] CUVIER
CUVIER [396] form of fossils, not found in other strata. No matter how the strata were bent and crumpled—even when one sank out of view and cropped up again miles away— this fact did not change. The charac teristic fossils bent, crumpled, sank out of view, and cropped up again with the stratum. In fact it was reasonable to identify a stratum by its fossil content, a point Smith made in a book published in 1816. This was a beautifully colored geologic map of England, the first of its kind. It was dedicated to Banks [331] who, with his usual generosity to the poor in science, had helped him. Since it could reasonably be assumed that a stratum nearer the surface was younger than one farther away, the strata offered a method for working out the history of life forms from the fossils. (Over a century before, Hooke [223] had suggested this in one of his inspired guesses.) For the first time it was possi ble to arrange the fossils in order of age. And since the oldest fossils were the ones that differed most from present-day life, with similarities growing stronger as the fossils grew younger, an evolutionary view became almost inevitable. Cuvier [396] was compelled to labor hard to resist it. In 1831 Smith was the first recipient of the Wollaston medal, funds for which had been set up in the will of Wollaston [388]. The presentation was made by Sedgwick [442], retiring president of the Geologic Society. The money award in volved was most welcome, for Smith’s travels in search of geologic data had pauperized him (not a really difficult task, to be sure) and had forced him to such shifts as selling his fossil collection to the British Museum. [396] CUVIER, Georges Léopold Chré tien Frédéric Dagobert, Baron (kyoo-vyayO French anatomist Born: Montbéliard, Doubs, Au gust 23, 1769 Died: Paris, May 13, 1832 Cuvier was descended from French Huguenots who had been forced into Switzerland after Louis XIV’s suspension of toleration. His father, although a Swiss national, was serving in the French army at the time of Cuvier’s birth. In 1793 Cuvier’s birthplace was annexed to France by the revolutionaries, and it has remained French ever since. Cuvier be came a French citizen automatically with that.
Cuvier remained an active Protestant all his life, but he received constant honor and advancement in predomi nantly Roman Catholic France under a variety of forms of government. This was not altogether surprising, for in his lifetime he became the most eminent Eu ropean scientist and virtually an intel lectual dictator in the field of biology. For a time in his youth Cuvier seemed to be headed for the ministry, but as a precocious child he had been fascinated by Buffon’s [277] books and while tutor to a Protestant family of the French aris tocracy he grew seriously interested in science. At that time, too, he met a zool ogist who in 1795 obtained for him a post at the Museum of Natural History in Paris, where he engaged in his re searches to such good effect that he be came permanent secretary of physical and natural sciences of the Institut Na tional in 1803. While at the museum he refused, in 1798, an offer to accompany Napoleon Bonaparte on his expedition to Egypt, which was just as well for him, because on the whole it was a disastrous adven ture. It was in that period, too, that he became interested in anatomy and, in par ticular, in the comparison of the anat omy of one species with another, a study that he brought to a high pitch of excel lence. In fact he came to understand the necessary relationship of one part of a body with another so well that from the existence of some bones he could infer the shape of others and so, little by little, reconstruct the entire animal (a process that even today strikes laymen with amazement and incredulity). He can thus be considered the founder of the science of comparative anatomy. Cu vier’s appreciation of how one part of an organism made other qualities necessary is exemplified in a famous story. One of 264 [396] CUVIER
CUVIER [396] his students dressed up in a devil’s cos tume and, with others, invaded Cuvier’s room in the dead of night and woke him with a grisly “Cuvier, Cuvier, I have come to eat you.” Cuvier opened one eye and said, “All creatures with horns and hooves are herbivores. You can’t eat me.” Then he went back to sleep. It seems natural that a comparative anatomist should be interested in the classification of species, and Cuvier most certainly was. He extended and perfected the classificatory system of Linnaeus [276] by grouping related classes (Lin naeus’ broadest classification) into still broader groups called phyla. Cuvier di vided the animal kingdom into four phyla: Vertebrata, Mollusca, Articulata (including all jointed animals), and Ra- diata (everything else). In doing so he laid stress on the internal structures of animals, which most clearly indicate relationship, rather than on surface superficialities. Modem classification is more complex than Cuvier’s—some two dozen animal phyla are now recognized, for instance—but Cuvier’s principles have guided biologists in their classifica tions ever since. Cuvier’s younger associ ate, Candolle [418], applied those princi ples to the classification of plants, com pleting what had been begun by Jussieu [345],
Cuvier was the first to extend the sys tem of classification to fossils. It seemed to his anatomical eye that every fossil he found, although not quite like any living forms, clearly belonged to one of the four phyla he had established. He could even classify them in subgroups and in clude them generally in his classification of life along with living forms. He began in 1796, with a fossil that was clearly an elephant, though neither of the two liv ing species. He showed that an extinct South American animal, the Megathe
much smaller sloths of today. In 1812 he exhibited the much more spectacular fos sil of a flying creature, with true wings, which was nevertheless clearly a reptile. He named it a “pterodactyl” (“wing finger”) because the membrane of its wing was stretched out along one enor mous finger. For these discoveries Cuvier is called the founder of paleontology. He missed identifying the true dinosaurs, however. When the teeth of such crea tures—the first to be discovered—were submitted to him in 1822, he judged them to be mammalian rather than rep tilian and to belong to an extinct species of rhinoceros. Yet Cuvier had a blind spot, and this was his devotion to the literal words of Genesis. He saw with his own eyes that the fossils must be ancient, buried as they were deep in rocky strata. He saw also that the deeper the fossil and the older the rock, the more that fossil differed in structure from modem life forms. It would seem, from the superior wisdom of our hindsight, that it would be an easy leap to some evolutionary theory, and indeed Cuvier’s older con temporary Lamarck [336] advanced one. Nevertheless Cuvier was a firm an tievolutionist. To account for the fossils and their gradations with time, he adapted the catastrophism of Bonnet [291]. The earth, he suggested, was peri odically inundated in a world-wide flood. After each flood, life would be created anew. The fossils would then be rem nants of ages before the most recent ca tastrophe. Needless to say, Cuvier was a neptunist after the fashion of Werner [355].
The last catastrophe, Cuvier believed, was the Flood described in Genesis, through which, by divine intervention, some living things had survived. In this way the vast age of the earth (as re vealed by a study of the strata) could be squared with the biblical account by supposing the Bible to deal only with the latest postcatastrophic age, that being the only era of importance to man in the story of salvation. In 1808 Napoleon put Cuvier in charge of investigating the state of edu cation in France. His eminence was such that the returning Bourbons made no at tempt to penalize him but used him in stead. He was made chancellor of what had been the Imperial University and was now again the University of Paris, and also served in the cabinet of Louis XVIII, who had had enough of exile and
[397] HUMBOLDT
HUMBOLDT [397] wanted matters to last his lifetime. (They did.) In 1818 Cuvier was elected to the French Academy and by that time he was wealthy (and grossly obese, too). In 1824 Louis was succeeded by his archreactionary brother, Charles X, and Cuvier fell out with him. In 1831, after Charles X had been once more driven into exile, the new king, Louis Philippe, made Cuvier a baron and, the next year, minister of interior, a post he did not live to accept. All of Cuvier’s eminence, however, could not keep the theory of catas- trophism alive very long. Increasing knowledge of paleontology made more and more unlikely any world-wide catas trophe that had wiped out all life. There were many animals whose life spans as closely related groups of species stretched across any boundary lines that could be drawn between eras. Cuvier had suggested only four catas trophes, but under his followers after his death the number grew to as many as twenty-seven. Nevertheless, even as Cu vier was dying in the cholera epidemic of 1832, Lyell [502] was forcing catas- trophism into a catastrophe of its own and was establishing the dominance of the uniformitarian doctrine of Hutton [297].
Cuvier was another of the monsters of erudition who are to be found here and there in the history of science. He is sup posed to have virtually memorized the contents of the nineteen thousand vol umes in his library. [397] HUMBOLDT, Friedrich Wilhelm Heinrich Alexander, Baron von German naturalist
Humboldt, the son of a military officer who served as an official at the court of Prussia’s Frederick II, was, on his mother’s side, descended from those Hu guenots driven from France by Louis XIV. He was an incredible personality. His life of feverish activity, broad inter ests, and large accomplishments seems too much to be squeezed into even the ninety years he lived, though it must be said that he remained unmarried and was therefore spared the distractions of a wife and children. His education was sporadic but a year at Gottingen in 1789 was sufficient to inspire him with a vast interest in sci ence, particularly botany. In 1790 he began the first of many journeys; this one, modestly, merely through western Europe where he had the occasion of meeting various men of science. Back home he enrolled in the school of mines at Freiburg and absorbed, at the source, the fallacious neptunism of Werner [355].
Humboldt decided to be a geologist and mining engineer and for several years was inspector of mines at Bayreuth. He filled the post admirably and also found time to experiment with the electrical currents in muscles and nerves, a phenomenon recently discov ered by Galvani [320]. Humboldt backed Galvani in his dispute with Volta [337] and was on the losing side. Humboldt’s mother died in 1796 and Humboldt’s share of the inheritance set him free of any need to earn a living. He could indulge his passion for travel to its fullest extent. In 1799 he set sail on what was to be a five-year visit to the American continents, beginning this par ticular journey by having to elude British warships, for the Napoleonic Wars were beginning. His voyage consisted of exploration— for he navigated the length of the Ori noco and verified its connection with the Amazon drainage system—and scientific investigation, for he collected reams of botanical material and geological speci mens. (By the end of his life, he had collected sixty thousand plants, including thousands of species never described be fore.) He studied the ocean currents off the western coast of South America (and the current there is still called the Hum boldt Current in his honor). He also studied the American volcanoes and noted their occurrence in straight lines as though they were following some deep- buried flaw in the earth’s crust. He mea sured the decline in magnetic intensity as Download 17.33 Mb. Do'stlaringiz bilan baham: 
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