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[456] PONCELET GMELIN [457]
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[456] PONCELET
GMELIN [457] velocity of those waves. In that case how was it planets could move through the ether without any detectable inter ference? Men such as Brewster [433] re fused to accept the wave theory if it meant accepting such an ether and it was only the work of Cauchy [463] that en abled others to swallow it at all. But Fresnel’s work was accepted by physicists generally and Melloni [504] carried it beyond the visible spectrum. A half year before his death Fresnel received the Rumford medal from the Royal Society for his work. [456] PONCELET, Jean Victor (pohns- lay') French mathematician Born: Metz, Moselle, July 1, 1788 Died: Paris, December 23, 1867 Poncelet was of illegitimate birth, though he was later legitimized by his fa ther, a well-to-do landowner and lawyer. He studied military engineering at the École Polytechnique, where he studied under Ampère [407] among others, grad uating in 1810. He then joined the French army in 1812 as a lieutenant of engineers, just in time to take part in Napoleon’s grand offensive into Russia and (as is the habit with offensives into Russia) the grim retreat that followed. Poncelet was left for dead at the battle of Krasnoi on November 17, 1812, dur ing the retreat. Brought back to life by those who noted he was not quite dead, he was taken to prison through a four- month march in the depth of winter to Saratov on the Volga River and kept there till June 1814. He returned to France only after Napoleon’s fall, and he was then promoted to captain. Poncelet spent the long months of imprisonment meditating on geometry. The fruits appeared in 1822 when he published a book on projective geometry. It was a new look at an old field (roughly, the study of shadows cast by geometric figures) and previously knotty problems now yielded easily. Although Poncelet’s views were at first vigorously opposed by Cauchy [463], his book is usually considered to be the foundation of modem geometry. Ponce let also brought back the abacus (a simple computing device consisting of counters strung on wires) from Russia. It had been used in the West in medieval times, but it had long since been entirely forgotten and was now treated as a great novelty. After the war he taught mathe matics at Metz and at Paris, gaining professorial status in 1838. [457] GMELIN, Leopold (guh-may'lin) German chemist Born: Gottingen, Hannover, Au gust 2, 1788 Died: Heidelberg, Baden, April 13, 1853 Gmelin was a member of a dynasty of scientists. His father, uncle, and grandfa ther were all noted chemists, and his nephew was to be another. His great-un cle was J. G. Gmelin [280]. After spend ing a year with Vauquelin [379] in Paris, Gmelin received his doctorate at Gottin gen in 1812 and the next year accepted a post on the faculty of Heidelberg and eventually became its first full professor of chemistry. He was the discoverer of potassium ferrocyanide in 1822 and of Gmelin’s test for bile pigments. He stud ied the digestive juices of the stomach and pancreas. His best-known accomplishment is the publication of an encyclopedic textbook,
sented the first systematization of the field after the Lavoisier [334] revolution. The book demonstrates the growth of or ganic chemistry in the early nineteenth century. In the first edition (1817) there were three volumes, one of which, the smallest, was devoted to the substances of living or once-living tissue, substances to which Berzelius [425] had given the name organic a decade earlier. In 1843 Gmelin put out the fourth edition in nine volumes. Six of these nine volumes were devoted to organic substances. Gmelin was the first to use the terms “ester” and “ketone” as names for two common classes of organic compounds. The organic portion was eventually 307 [458] BOUCHER
SABINE [459] abandoned by Gmelin’s successors in the sixth edition and that part of the task was then taken up by Beilstein [732]. [458] BOUCHER DE CREVECOEUR
shay' duh krehv-keur' duh pehrt) French archaeologist
ber 10, 1788 Died: Abbeville, Somme, August 5, 1868
Boucher was the son of a botanist who had influence with Napoleon. The young man was therefore employed by Napo leon on various diplomatic missions to Germany and Austria. After the fall of Napoleon and the return of the Bour bons, Boucher quietly withdrew to the provincial town of Abbeville, where, be ginning in 1825, he served as controller of customs. His interests were wide. Mainly he aspired to be a literary figure, but he also made a hobby of archaeology. In 1837 he dug up crude axes near Abbeville, which from their position in the strata he judged could only be many thousands of years old like those found half a cen tury before by Frere [324]. Furthermore, they were clearly artifacts and could only have been made by man. The axes, however crude, were as much evidence of the existence of man, he said, as the discovery of an entire Louvre would have been. In 1846 he published a book on his findings, together with his most careful observations and conclusions. The book created a furor. The views of Cuvier [396], though displaced in En gland by the work of Lyell [502], were still all-powerful in France. The fol lowers of Cuvier were catastrophists and might admit that fossils in general were extremely ancient, but man himself, they held, could not be. Man was a creature of the most recent age, and to suppose him to be more than six thousand years old was to fly in the face of Cuvier and the Bible. Boucher found he could not get a hearing or persuade anyone to come and look for himself. What he had done was to find the first evidence of Stone Age man, who, we now believe, came into existence a million years ago and more; but the discovery merely brought him a decade of frustration. During the 1850s archaeologists began to turn up more ancient tools, and the evidence piled up despite all the Cu- vierists could do. Several English scien tists, including Lyell, had traveled to France and visited the spots where Boucher had found his axes. They de clared themselves on his side and the Royal Society officially accepted the an tiquity of man as established. Lyell was shortly to write a book on the subject and the way was clear for the discovery not only of ancient tools but also of fos sils of ancient men of species and genera other than that of modem man. This line of research was to establish evolutionary theory at its most sensitive spot—the de scent of man. [459] SABINE, Sir Edward (say'bin) British physicist
14, 1788 Died: Richmond, Surrey, England, June 26, 1883 Sabine served as an artillery officer in the army, eventually reaching the rank of major-general. He went on Arctic ex peditions in the years following the con clusion of the Napoleonic Wars and, it occurred to him that in traveling the world over, he could study earth as an astronomical body. Thus, in 1821 and 1822 he sailed hither and yon in the Atlantic making measurements of the period of a pendu lum swing in order to measure the pull of gravity and determine the exact shape of the earth. He was a person who roused great en mities among other scientists through his political maneuverings. He was even ac cused by some of falsifying data, though he may only have been naïve in using numbers. However, he did make one im portant discovery. In 1852, he was able to demonstrate that the frequency of dis turbances in earth’s magnetic field paral leled the rise and fall of sunspot num- 3 0 8
[460] THOMSEN
OHM [461] bers on the sun. This was the first exam ple of a phenomenon linking earth and sun by some means other than the sun’s radiation of light and of its gravitational effect.
He was president of the Royal Society from 1861 to 1871 and was knighted in 1869. [460] THOMSEN, Christian Jurgensen Danish archaeologist Born: Copenhagen, December 29, 1788
Died: Copenhagen, May 21, 1865 Thomsen was the son of a merchant and managed his father’s business till 1840. His real interest, however, was in archaeology, and his position as curator of the Danish National Museum from 1816 on gave him scope for that activity. He studied the characteristics of the tools from different periods of prehistory and, in 1834, on the basis of the pre dominant materials of which those tools were made, he divided early human his tory into the Stone Age, the Bronze Age, and the Iron Age. It is a division that is still used (with refinements) and is well known even to the average nonscientist. This division agreed with the sugges tion of Lucretius [53], which had been advanced on a far more intuitional basis. [461] OHM, Georg Simon (ome) German physicist
16, 1789 Died: Munich, Bavaria, July 6, 1854
Ohm was the son of a self-taught master mechanic who was interested in science and who went to some pains to see that the youngster received a scientific education. Young Ohm entered the University of Erlangen and obtained his Ph.D. there in 1811. Science was not, however, to deal kindly with Ohm. He taught in high schools, but his am bition was to achieve a university ap pointment. To do this he had to produce some important research work and he tackled the new field of current elec tricity that had been opened by Volta [337]. But he was poor and equipment was hard to get, so he made his own. In particular he drew his own wires, and the influence of his mechanic father stood him in good stead. Ohm decided to apply to the flow of electricity some of the discoveries made by Fourier [393] concerning the flow of heat. Just as the rate at which heat flowed from point A to point B de pended in part on the temperature difference between those two points and in part on the ease with which heat was conducted by the material between, so the rate of flow of electric current should depend on the difference in electrical po tential between points A and B and on the electrical conductivity of the material between. By working with wires of different thicknesses and lengths, he found the quantity of current transmitted was in versely proportional to the length and directly proportional to the cross-sec tional area of the wire. He was in this way able to define the resistance of the wire and in 1827 to show that there was a simple relation between that resistance, the electric potential, and the amount of current carried. This came to be called Ohm’s law and can be expressed: “The flow of current through a conductor is directly proportional to the potential difference and inversely proportional to the resistance.” (Nearly half a century earlier Cavendish [307] had discovered this relationship, but he had never pub lished.)
This was Ohm’s only first-class contri bution to science, but one first-class con tribution is quite enough, and he de served his university appointment. He did not get it, however. His work stirred up a good deal of opposition and resent ment, apparently because Ohm tried to base his results on theory and some of his audience did not understand that good, thorough experimental work was also involved. In any case Ohm met with so much criticism that he was forced to resign even his high school position. For six years he lived in poverty and bitter disappointment, while very slowly
[462] REDFIELD
CAUCHY [463] his work became known and appreciated outside Germany. He found himself, probably to his own surprise, coming to be held in honor. The Royal Society gave him its Copley medal in 1841 and made him a member in 1842. Finally, prophet Ohm, with some help from Lud wig I of Bavaria, came to be honored even in his own country and he was ap pointed to a professorship at the Univer sity of Munich in 1849 so that the last five years of his life were spent in the sun of ambition realized at last. What’s more, a statue was raised to him in Munich after his death and a street was named in his honor (for dead men, as always, are easy to appreciate). His name is further immortalized in the fact that the unit of resistance is the ohm. Thus, when a current of one am pere passes through a substance under a potential difference of one volt, that sub stance has a resistance of one ohm. Fur thermore, the unit of conductance (which is the reciprocal of resistance) is the mho—Ohm’s name spelled backward —a whimsical device introduced by Kel vin [652]. [462] REDFIELD, William C. American meterologist
March 26, 1789 Died: New York, New York, February 12, 1857 Redfield was the son of a seafarer and was apprenticed to a saddlemaker in 1803. On a trip from Connecticut to Massachusetts soon after a hurricane had ripped through New England on Septem ber 3, 1821, he noticed the manner in which trees had fallen. From this, he deduced that the storm spiraled and that it was, in fact, what he called a gigantic “progressive whirlwind.” He confirmed this in connection with violent storms he noted in New York. In 1831 he published his evidence to the effect that storm winds whirl coun terclockwise about a center that moves in the normal direction of the prevailing winds. His frequent trips made him interested in transportation; in steam engines and railroads. He laid out the routes of the Harlem and the Hartford-New Haven railroads, for instance. He helped found the American Association for the Ad vancement of Science and served as pres ident at its first meeting in September 1848.
[463] CAUCHY, Augustin Louis, Baron (koh-shee') French mathematician
May 23, 1857 Cauchy was the son of a government official who fled with his family to a small village to escape the Terror. There young Augustin first met Laplace [347] and Berthollet [346]. In 1805, Cauchy entered the École Polytechnique where Ampère [407] was one of his teachers. He intended to be a civil engineer and for a while served in Napoleon’s army, but his health failed and his friends Lagrange [317] and La place persuaded him in 1813 to turn to the less physically demanding pursuit of pure mathematics. In 1816, when Monge [340] was ex pelled from the Academy of Sciences, Cauchy replaced him. In one important respect his mathe matical work impinged upon physics. He was the first to attempt to work out a mathematical basis for the properties of ether, that solid-but-gas that let both light waves and planets pass through it self. His work made it possible for scien tists to accept the ether without loss of respectability, but the theory was not en tirely satisfactory. Nor were the later at tempts to improve it by such men as Maxwell [692] thoroughly successful. In fact, no theory was ever successful, and the experiment of Michelson [835] and Morley [730], a generation after Cauchy’s death, made matters worse. Physicists were for a century caught in a cruel dilemma between the apparent ne cessity of an ether to explain the nature of light and the apparent impossibility of an ether with such contradictory proper 310 [464] BOND
SCHWABE [466] ties. It required the work of Einstein [1064] to set them free at last. Cauchy’s later life was beleaguered by political controversy for he was aggres sively ultraconservative both in politics and in religion. He was an ardent adher ent of the Bourbons. When Charles X (who made Cauchy a baron), the last French king of the Bourbon line, went into exile in 1830, Cauchy also went into exile in Italy to avoid swearing allegiance to the new king, Louis Philippe. He taught at the University of Turin while there. Cauchy returned to France in 1838 but would not swear allegiance to Louis Napoleon when that nephew of the first Napoleon came to power in 1848 as president of the Second Republic and later made himself Emperor Napoleon HI. He got away with it, as Arago [446] did, and indeed received a professional appointment at the Collège de France. [464] BOND, William Cranch American astronomer Born: Portland, Maine, September 9, 1789
Died: Cambridge, Massachusetts, January 29, 1859 Bond, who came from a poor family, was self-educated. His early profession was that of a watchmaker, but a solar eclipse in 1806 fascinated him and as tronomy came to be his hobby. He es tablished a private observatory that was the best in the country. When he was fifty his worth was recognized by Har vard, which invited him to move his ob servatory to the university (where he was kindly allowed to serve as its first di rector without pay) and this he did. His son, G. P. Bond [660], succeeded him as director of the Harvard College Observa tory after his death. In 1850 the elder Bond photographed the bright star Vega—the first star to have its picture taken. In 1851 a photo graph he took of the moon was a sensa tion at the Great Exhibition in London. In 1850 he had detected a third, dim ring within Saturn’s two bright ones. (The existence of several rings about Saturn, rather than one only, was ex plained by Kirkwood [586] during the course of the next decade.) This third ring was called the crape ring because of its dimness. Stars could be seen through it, indicating it was not solid, a situation Maxwell [692] had suggested was true for the bright rings as well, from purely theoretical considerations. Lassell [509] discovered the crape ring independently only a few days after Bond. [465] BRIGHT, Richard English physician Born: Bristol, Gloucestershire, September 28, 1789 Died: London, December 16,1858 Bright was bom into a well-to-do banking family and had no economic in securities. He received his medical de gree from the University of Edinburgh in 1813, having interrupted his education in a carefree manner to go off on expedi tions to Iceland as the naturalist of the party. He was an important clinician and wrote an important textbook of medicine with Addison [482], in which is the first good account of appendicitis. He was interested in a wide variety of diseases, studying them meticulously and making careful postmortem investi gations. His name is particularly as sociated, however, with the clinical symptoms of a serious kidney disorder that is now called “Bright’s disease.” This he reported on in 1827. [466] SCHWABE, Heinrich Samuel (sbvah'buh) German astronomer Born: Dessau, Anhalt, October 25, 1789 Died: Dessau, April 11, 1875 Schwabe was a pharmacist who at tended lectures at the University of Ber lin between 1810 and 1812, and these drew his interest to astronomy. He needed some phase of the science that would occupy him in the daytime since he worked by day, and had to sleep at Download 17.33 Mb. Do'stlaringiz bilan baham: 
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