Biographical encyclopedia
[439] BESSEL PROUT [440]
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[439] BESSEL
PROUT [440] ble to the solutions of many problems both in and out of astronomy. His most renowned feat was that of being the first to achieve a three-century dream of astronomers, the determination of the parallax of a star. He fixed on the dim star 61 Cygni (discovered by Piazzi [341] a generation earlier), which he as sumed to be unusually near the earth, despite its dimness, because of its rapid proper motion, the most rapid, in fact, then known. After careful observations of its position in comparison with two still fainter (and presumably quite dis tant) stars nearby, he was able to indi cate that it had a definite parallax, though a very tiny one. Judging by its parallax, 61 Cygni turned out to be some 35,000,000,000,000 miles away. Since light, even at its velocity of 186,282 miles a second, travels less than six trillion miles in a year, 61 Cygni can be said to be approximately six light- years (a term that thus entered astron omy) from the earth. The size of the universe was, in this way, greatly en larged in the mind of man. Kepler [169], after all, had suspected the entire starry sphere to be perhaps 0.1 light-year away and Newton [231] had dared expand that figure to perhaps two light-years. Bessel’s announcement of his discovery in 1838 put the finishing touch to the Copemican theory, for the parallax of a star, like the aberration of light, discov ered by Bradley, was visible evidence of earth’s motion through space. The discovery of parallax was “in the air.” It often happens in science that a problem defeating all scientists for a long period of time is solved by several al most simultaneously. Within two years Henderson [505] and Struve [483] had independently measured the parallax of a star. By the mid-twentieth century, nearly six thousand stars had had their parallaxes determined and distances up to one hundred light-years had been directly measured in this manner. Bessel used an instrument of his own design, a heliometer, in measuring the tiny displacements of 61 Cygni. He had Fraunhofer [450] make it for him. In 1844 he used the instrument for a dis covery almost as striking. He noted, in 1834, that the stars Sirius and Procyon showed tiny displacements that were not parallactic in nature but were like tiny waves in their proper motion. This he at tributed, in 1841, to their revolutions about unseen companions, a theory later proved correct by Clark [696]. Bessel’s discovery marked the begin ning of the shift of astronomers’ atten tion from the solar system, which had been so neatly and (it almost appeared) so finally put into shape by Laplace [347], to the outer universe of the stars. However, this did not mean that the solar system was exhausted. Schwabe [466] proved this before Bessel’s death by a remarkable discovery concerning the sun itself. Beer [499] even did yeo man work in so prosaic a job as mapping the moon. And, indeed, Bessel’s last few years were concerned with the solar system, for he took up the question of the anom alous motion of Uranus and the possi bility that an undiscovered planet might exist beyond it. He calculated the masses of Jupiter and Saturn with greater preci sion than ever before and showed that the irregularities in the motion of Uranus could not be explained by the gravitational attractions of those two giant planets. He died of cancer, how ever, before he could carry the search farther and too soon to witness the suc cess of Leverrier [564] and John C. Adams [615] in solving this problem. [440] PROUT, William English chemist and physiologist Born: Horton, Gloucestershire, January 15, 1785 Died: London, April 9, 1850 Prout, the son of a farmer, was a prac ticing physician who had obtained his medical degree at Edinburgh in 1811. He interested himself in organic chemis try, that is, the chemistry of living or once-living tissue. This was part of the trend of the times. The first few decades of the nineteenth century saw an acceler ation of the shift from the emphasis on the substances of the inorganic world,
[440] PROUT
DULONG [441] which had occupied the attention of the medieval alchemists and of the early chemists. More and more chemists turned toward the more fragile and com plex compounds associated with living organisms. Men like Pelletier [454], Guthrie [435], and Kidd [409] were dis covering important organic substances at a pace that was to swell the organic sec tions of Gmelin’s [457] textbook from one volume to six in a quarter century. After the mid-century mark, organic chemistry almost inundated inorganic. Oddly enough, one of Prout’s major discoveries was that what had been con sidered a strictly inorganic substance was actually intimately involved in the pro cess of digestion. In 1824 he identified the acid in stomach secretions as hydro chloric acid. This was rather a stunner for the chemists of the time, for to have the powerful metal-corroding, flesh-burn ing hydrochloric acid in intimate contact with the delicate stomach lining seemed unbelievable. (The safety of the stomach lining is still not entirely explained, but the hydrochloric acid is there all right.) Prout’s interest in nutrition and diges tion, particularly, made him one of the early leaders in the field, outshone per haps only by Magendie [438]. It was Prout who in 1827 was the first to divide the components of foodstuffs into the fa miliar groups that today we call carbohy drates, fats, and proteins. However, Prout’s present fame is in neither medicine nor biochemistry. In 1815 he published an anonymous article in which he pointed out that the atomic weights of the elements were all integral multiples of that of hydrogen, which was the lightest known element. Thus, if hy drogen is given an atomic weight of 1, then (using modern values of atomic weights as examples) carbon has an atomic weight of 12, nitrogen of 14. oxy gen of 16, sodium of 23, and so on. Prout therefore suggested that the atoms of all the elements were made up of conglom erates of varying numbers of hydrogen atoms. When his authorship became known, this suggestion was called Prout’s hypothesis. Prout’s daring hypothesis (with Dal ton’s [389] atomic theory but a decade old) spurred on the determination of ac curate atomic weights and, before long, facts seemed to rule it out. Thus, the atomic weight of chlorine was definitely shown to be about 35%, that of mag nesium about 24%, and so on. Prout’s hypothesis seemed dead, and for a cen tury, if mentioned at all, it was merely as an idea that had misfired. It was not until the twentieth century that new views of the atom, arising out of the Second Scientific Revolution of the 1890s, revitalized the notion. As a result of the work of Soddy [1052] and Aston [1051], a new form of Prout’s hy pothesis was established and Prout was found to be not wrong, but merely a century premature. [441] DULONG, Pierre Louis (dyoo- lawng')
French chemist Born: Rouen, Seine-Marne, Feb ruary 12, 1785 Died: Paris, July 18, 1838 Dulong’s parents were dead before he was five and he was brought up by an aunt. He practiced as a physician who conceived it his duty to hand out medi cine without charge and to treat the poor without asking for payment. Naturally he was a failure as a physician. He was an equally dedicated chemist, beginning as an assistant to Berthollet [346] and eventually impoverishing him self to buy equipment. In 1811 he had the bad fortune to discover nitrogen tri chloride, an extremely touchy and power ful explosive, and during his investi gations he lost an eye and nearly a hand in two explosions; nevertheless he con tinued his investigations of the com pound. Davy [421] also worked on the substance, once he heard of its existence, also nearly killed himself, also continued working.
In 1820 Dulong became professor of physics at the ficole Polytechnique and finally director of the school in 1830. His most important work was on heat, in collaboration with the physicist Petit [476]. In 1818 they showed that the specific heat of an element was inversely
[442] SEDGWICK
AUDUBON [443] related to its atomic weight. Thus if the specific heat of a new element could be determined (which was easy) a rough idea was at once obtained of its atomic weight (which, to determine otherwise, might be difficult). This law of Dulong and Petit was very useful in determining atomic weights, and Berzelius [425] (under whom Dulong, as a young man, had studied), after early doubts, came round to using it. In 1826 Dulong was elected a foreign member of the Royal Society.
Dulong also collaborated with Thé nard [416] in the study of catalysis and with Arago [446] in the study of high- pressure steam. [442] SEDGWICK, Adam English geologist Born: Dent, Yorkshire, March 22, 1785 Died: Cambridge, January 27, 1873
Sedgwick, the son of a vicar, was in volved in religion and science, donning the cloth and becoming a professor of geology at Cambridge in the same year, 1818. Two years with Werner [355] marked the beginning of his geologic ca reer. In his geologic investigations he stud ied ancient Welsh rocks, which, as it turned out, were of the type of the oldest fossil-bearing rocks. He gave the name Cambrian (from an ancient name for Wales) to the geologic era they repre sented. He studied and worked out the rocks of the Devonian era along with Murchison. Lyell [502], Murchison [477], Sedgwick, and some lesser person alities represent what is sometimes called the heroic age of geology. Certainly they hammered out modem geology among them. An unfortunate disagreement over pri ority eventually broke up the fruitful partnership of Sedgwick and Murchison, however. In 1851 Sedgwick was awarded the Wollaston medal, the award being pre sented by Lyell. Unlike Lyell, Sedgwick remained strongly opposed to Darwin’s [554] theory of evolution. This had its elements of irony, for the young Darwin had won his scientific spurs during a geologic field trip to North Wales along with Sedgwick, and Sedgwick had been the first to recognize the young man’s ge nius.
[443] AUDUBON, John James (aw'doo- bon)
French-American ornithologist Born: Les Cayes, Santo Domingo (now Haiti), April 26, 1785 Died: New York, New York, January 27, 1851 Audubon was the illegitimate son of a French sea captain and a servant girl who traveled aboard his ship. This cap tain, however, had fought at Yorktown in alliance with George Washington, and so Audubon began life as American as a foreigner could be. Audubon’s mother died soon after his birth and his father cared for him, adopted him officially in 1794 and took him to France. The captain’s legal wife, herself childless, cared for him lovingly. In France young Audubon happened to live near a famous naturalist. His natural love of living things was there well fos tered. He had some training in art, too (some say), under Jacques Louis David, one of the best-known painters in France though this tale seems doubtful. At the age of eighteen he was sent to America to take charge of his father’s American properties near Philadelphia and, incidentally, to avoid being drafted into Napoleon’s armies. He remained in America for the rest of his life except for occasional trips abroad. While at Philadelphia, he banded some birds and found that they returned to the region in following years. This initiated the study of bird migrations. Audubon was a failure in business be cause no necessity could prevent him from spending most of his time observ ing nature. In 1819 he was jailed for debt. This might seem to put a strain upon his marriage as well, but his mar riage was successful. In 1820, out of jail, Audubon traveled 299 [444] BEAUMONT
ARAGO [446] west to the wilderness and began his life’s work of painting birds, while his wife supported the family. In 1826 he had enough paintings to take to England in search of a publisher, and there his worth was recognized. By 1838 he had completed 435 paintings, among the most beautiful natural history studies ever done. The collection of colored plates of those paintings sold at $1,000 a set.
Audubon was one of the first Ameri can conservationists, and modem conser vationists are organized into Audubon societies named in his honor. In 1900, when the Hall of Fame for Great Ameri cans was established, he was one of those honored. [444] BEAUMONT, William (boh'mont) American surgeon Born: Lebanon, Connecticut, No vember 21, 1785 Died: St. Louis, Missouri, April 25, 1853 _ Beaumont, the son of a farmer, stud ied medicine in a rather haphazard way and gained a license in time to serve as an army surgeon in the War of 1812. He might have lived out his life in obscurity but for an unusual accident. In 1819 he was appointed post sur geon at a frontier post in northern Mich igan. While he was there, on June 6, 1822, a nineteen-year-old French-Can- adian, Alexis St. Martin, was acci dentally shot in the side. It was a shot gun blast at close range and he received a terrible wound. Beaumont treated him with great care and skill and the young man recovered and enjoyed good health, even though he retained an opening (or “fistula”) nearly an inch across which led into his stom ach. In fact, the accident victim, who seemed at the point of death, lived to be eighty-two. Through this opening Beau mont, beginning in May 1825, was able to observe the changes in the stomach under different conditions and to extract samples of gastric juice, which he sent all over the world. (In the process, he so
bullied his subject that poor St. Martin eventually ran away from him.) Beaumont published his careful, de tailed studies in 1833, listing no fewer than 238 experiments, and this work not only served as a source for much early information on the process of digestion but also stirred up interest in the field and suggested to Bernard [578] the use of artificial fistulas in animals for further research. Beaumont resigned from the army in 1840 and practiced medicine as a private citizen in St. Louis for the rest of his life.
[445] LISTER, Joseph Jackson English optician Born: London, January 11, 1786 Died: West Ham, Essex, October 24, 1869 J. J. Lister, a wine merchant, was the father of the more famous Joseph Lister [672]. The elder Lister was self-taught and devoted his efforts to the develop ment of a proper lens for the micro scope.
Dollond [273] had developed an achromatic lens for the telescope about seventy years earlier and one was needed desperately for the microscope. Without one, there was a limit to the clarity with which objects could be seen, for colored “ghosts” blurred everything. Finally, in 1830, Lister succeeded and only from that day can modem microscopy be said to date.
In 1834, for instance, Lister succeeded in seeing the true biconcave form of red blood corpuscles for the first time. [446] ARAGO, Dominique François Jean (a-ra-goN) French physicist Born: Estagel, Pyrénées- Orientales, February 26, 1786 Died: Paris, October 2, 1853 Arago, the son of a minor government official, contributed to half a dozen fields and the spread of his talents kept him from first-rank accomplishments in any
[446] ARAGO
CHEVREUL [448] one of them. He intended to enter the army but his excellence in science di verted him to a post at the Paris Obser vatory, which he obtained with the help of Laplace [347], He was making accu rate surveys in France and Spain with Biot [404] from 1806 on. Spain was then engaged in a bitter guerrilla war against Napoleon, so that these surveys involved hairbreadth escapes that would have read well in a thriller. He became a professor at the École Polytechnique in 1809, succeeding Lalande [309], As it happened, he was an excellent lecturer and a good ob server, too. He discovered the solar chromosphere. He also began to study the physics of light. First he supported the particle theory but was converted to the wave theory and lost Biot’s friend ship.
He pointed out to Fresnel [455], who was working on the mathematics of wave theory—and whom he had joined —that Young [402] had performed im portant experiments in this connection. However, when Fresnel adopted Young’s suggestion of transverse light waves, rather than longitudinal, Arago did not dare go along and withdrew. When Arago heard of Oersted’s [417] experiment he checked the magnetic prop erties of an electric current further. He ran a current through a copper wire and showed that it would attract unmagne tized iron filings as easily as a magne tized needle and that the current could make a magnet out of unmagnetized iron. This showed the wire became a true magnet when current flowed through it. Since it was copper that de veloped this magnetism, the experiment further showed that iron was not neces sary to the development of the magnetic force. In 1825 Arago became the first Frenchman to receive the Royal Soci ety’s Copley medal. Arago also expended his energies on politics. He was a fiery republican, par ticipating in the revolutions of 1830 and 1848. In the Second Republic (1848-1852) he served in the cabinet and was instrumental in having slavery abolished in the French colonies. He promptly resigned his post in 1852 when President Louis Napoleon made himself Emperor Napoleon III and demanded an oath of allegiance. However, the new emperor refused to accept his resignation and did not press for an oath. [447] AMICI, Giovanni Battista (ah-mee'chee) Italian physicist Born: Modena, March 23, 1786 Died: Florence, April 10, 1868 Amici, the son of a government official, graduated from the University of Bologna in 1807 and promptly took a position as a teacher of mathematics in a school in Modena. In 1831 he was in vited to Florence by its grand duke to head the observatory and museum of natural history there. Amici worked primarily in the field of scientific instrumentation, particularly that of the microscope. The achromatic microscope had finally come into use through the labors of many people, cul minating in that of J. J. Lister [445], but Amici, in making further ingenious ad justments to the lens system improved the clarity and magnification of micro scopes to the point where they could en large an object up to six thousand times. In 1840, he also invented the oil-immer sion microscope in which the lowermost lens is immersed in a drop of oil thus removing some of the sources of imper fection in focusing. He also built lenses, mirrors, and spec troscopic prisms for use in telescopes, and in each case made advances in the art. [448] CHEVREUL, Michel Eugène (sheh-vruhT) French chemist Born: Angers, Maine-et-Loire, August 31, 1786 Died: Paris, April 9, 1889 Chevreul was the son of a surgeon. His mighty life span of 103 years made it possible for him to watch a guillotin ing during the French Revolution when he was a seven-year-old, and the con Download 17.33 Mb. Do'stlaringiz bilan baham: |
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