Biographical encyclopedia
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131 [208] SYDENHAM
CASSINI [209] sufficiently intense to cause him to de vote the remainder of his short life to meditation, asceticism, religious writings (including the famous Pensées), and ill ness. The writings were brilliant and served to inspire Voltaire [261] but Pas cal worked on science and mathematics no more, except for one week in 1658 when he lived through a toothache by distracting his mind with a geometric problem, which he dispatched with great neatness. In his last years, in fact, Pascal declared reason an insufficient tool for understanding the physical universe, thus retreating beyond Thales [3], His best-known remark had nothing to do with science. It was to the effect that had Cleopatra’s nose been differently shaped, the history of the world would have been altered. [208] SYDENHAM, Thomas (sid'num) English physician
September 10, 1624 Died: London, December 29, 1689
Sydenham came of a family of the gentry that fought on the side of the Parliament in the English Civil War. Two of Thomas’s brothers died in the course of it and his oldest brother be came an associate of Cromwell and an important figure in the Commonwealth. Thomas himself fought, and reportedly narrowly escaped death on two occa sions. All the fighting interrupted his ed ucation, and he did not get his master’s degree till 1648. He began practicing medicine in 1656. The restoration of Charles II meant there was no chance of public life for Sydenham with his Parliamentary record so he turned entirely to medicine and made a huge success of it. Like Willis [205] he studied epidemics and the text book he wrote on the subject remained standard until the development of the germ theory of disease by Pasteur [642]. In the course of his practice, he insisted on detailed clinical observations and accurate records. He was the first to differentiate scarlet fever from measles, and it was he who first called it scarlet fever. He was the first to use opium de rivatives (laudanum) to relieve pain and induce rest. He popularized the use of cinchona (quinine) to treat malaria. He also used iron in the treatment of ane mia. He produced careful descriptions of gout and of Saint Vitus’s dance (still called “Sydenham’s chorea”). Before he died, he was being called the English Hippocrates. [209] CASSINI, Giovanni Domenico (ka-see-nee': French) (ka-see'- nee: Italian) Italian-French astronomer
June 8, 1625 Died: Paris, September 14, 1712 Cassini made his reputation in Italy, where he studied under Riccioli [185] and Grimaldi [199] and where, from 1650, he taught astronomy at the Uni versity of Bologna, succeeding to Ca- valieri’s [186] position. The story is that he originally studied astronomy in order to gather data to disprove the follies of astrology. In 1665 and 1666 he measured the pe riods of rotation of Mars as twenty-four hours, forty minutes. In 1668 he issued a table of the motions of Jupiter’s moons, which was later to serve Roemer [232] in his discovery of the velocity of light. He also established Jupiter’s period of rota tion as nine hours, fifty-six minutes, and was the first to study the zodiacal light. (This last is a faint illumination of the night sky, stretching outward from the sun along the line of the ecliptic. We know now that it is sunlight reflected from dust particles in interplanetary space.) Picard [204] of the Paris Observatory, who was always on the lookout for for eign talent, persuaded Louis XIV of France to invite Cassini to Paris in 1669. The observatory was being elaborately rebuilt at the time. Cassini took one look and demanded changes in design so that the buildings would be less ornamental and more useful. King Louis pouted, but agreed, and there at the Paris Observa
[209] CASSINI
BARTHOLIN [210] tory Cassini remained for the rest of his life, becoming a French citizen in 1673. He is often considered a French astrono mer, and his first names are often given as Jean Dominique. In Paris, Cassini continued his dis coveries. He located no fewer than four new satellites of Saturn using telescopes over one hundred feet long: Iapetus in 1671, Rhea in 1672, and Dione and Tethys in 1684. Then, having outdone his younger contemporary Huygens [215] in the matter of the Saturnian sat ellites (Huygens discovered only one), he went on to improve on Huygens’ most spectacular discovery, the rings of Saturn. In 1675 Cassini noted that the ring was actually a double one, the two rings being divided by a dark gap that is still called Cassini’s division. Cassini suspected the rings might con sist of myriads of small particles, but most astronomers, including Herschel [321], refused to accept that notion. They considered the rings solid, with Cassini’s division a dark marking upon it. Finally Maxwell [692] proved Cassini to have been right all along, a century and a half after the latter’s death. Outside the solar system, Cassini dis covered several stars to be double, in cluding the bright star Castor. His most valuable piece of work lay in his determination of the parallax of Mars in 1672 through his observations of the planet in Paris and Richer’s [217] simultaneous observations in French Guiana. This gave him a value for the distance of Mars. The relative distances of the sun and planets had been known quite accurately since the days of Kepler [169], so it was only necessary to deter mine any one of those distances accu rately to be able to calculate all the rest. From his value for the distance of Mars, Cassini calculated that the sun was eighty-seven million miles from the earth, a value confirmed that same year by Flamsteed [234]. This is too low a value by 7 percent, but it was the first determination ever made that was nearly right. Aristarchus [41] had placed the sun a mere five mil lion miles from the earth, while Posei- donius [52] had estimated forty million mileis and Kepler had actually cut that down to a guess (it was nothing more) of fifteen million miles. Cassini founded a dynasty of five suc cessive generations of astronomers that dominated French astronomy for over a century. This was not altogether fortu nate. Cassini himself was an opinionated, self-important person who was not nearly as good as he thought. Further more he was amazingly conservative for his times. He was the last of the great as tronomers to refuse to accept the helio centric views of Copernicus [127]. His descendants gradually adopted the new view of the universe but always a couple of generations too late. Thus the second of the line accepted Copernicus but rejected Kepler. The third of the line insisted that the earth was flattened at the equator when other astronomers were satisfied that it was flattened at the poles. And it was only the fourth of the line who could finally bring himself, a century after the fact, to accept Newton [231]. Eighteenth-century France suf fered a decline in astronomy because of the dead hand of the first Cassini, as eighteenth-century England was to suffer a decline in mathematics because of slavish adherence to Newton. [210] BARTHOLIN, Erasmus (bahr- too'lin) Danish physician Born: Roskilde, August 13, 1625 Died: Copenhagen, November 4, 1698
Bartholin was a member of a Danish medical dynasty. His father, brother, and son were all physicians, as he was him self. In 1654 he obtained a medical de gree at the University of Padua, and was professor of medicine at the University of Copenhagen from 1656 to his death. His fame, however, did not arise from anything connected with medicine. In 1669 he received a transparent crystal from Iceland (now called Iceland spar) and he noted that objects viewed through it were seen double. He assumed that the light traveling through the crystal was refracted in two different angles, so that
[211] REDI
BOYLE [212] two rays of light emerged where one had entered. This phenomenon he therefore called double refraction. Furthermore he noted that if he ro tated the crystal, one of the images re mained fixed while the other rotated about it. The ray giving rise to the fixed image he called the ordinary ray, the other the extraordinary ray. These terms are still used today. Bartholin was unable to explain these observations. Greater men than himself attempted it too, recognizing that any theory of light, if it were to be success ful, must explain double refraction. After all, why should some light refract through one angle, and the rest through another? Isaac Newton [231] developed a parti cle theory of light which did not explain double refraction, and Huygens [215] de veloped a wave theory that did not ex plain it. The whole matter of double refraction remained in a kind of cold storage where physicists refused to look at it until Young [402] finally established a new variety of wave theory a century and a half after Bartholin. Then and only then was double refraction ex plained and put to use in chemistry. [211] REDI, Francesco (ray'dee) Italian physician and poet
18, 1626 Died: Pisa, March 1, 1697 Redi obtained his medical degree at the University of Pisa in 1647, and was personal physician to two Medici grand dukes of Tuscany, Ferdinand II [193] and Cosimo III. As a poet, he is known chiefly for Bacco in Toscana written in 1685; but in the world of science he is known for reasons far more enduring. Or perhaps for one reason; a famous ex periment involving flies and their manner of breeding. It had long been held by many men, from casual observers up to careful thinkers such as Aristotle [29] and Hel mont [175], that some species of animals arose spontaneously from mud, decaying grain, or in general from corrupting mat ter. The living things that arose through such spontaneous generation were usu ally vermin such as insects, worms, frogs, and so on. One of the best attested cases was that of maggots, which ap peared in decaying meat, apparently out of the substance of the meat itself. In the small book on the circulation written by Harvey [174] about the time Redi was born, there was a speculation to the effect that small living things that appeared to be born spontaneously, might actually arise from seeds or eggs that were too small to be seen. Redi read this and in 1668 determined to test it. He prepared eight flasks with a variety of meats in them. Four he sealed and four he left open to the air. Flies could land only on the meat in the vessels that were open and only the meat in those vessels bred maggots. The meat in the closed vessels was just as putrid and smelly, but without maggots. To test whether it was the absence of fresh air that did it, Redi repeated the experiment without closing any flasks, but covering some with gauze instead. The air was not excluded, but flies were, and that was sufficient. There were no maggots in the gauze-covered meat. This was the first clear-cut case of the use of proper con trols in a biological experiment. Redi concluded that maggots were not formed by spontaneous generation but from eggs laid by flies. This finding might have been extended to all forms of life but that would have been permature. Leeuwenhoek [221] had just demon strated the existence of a new world of minute animals invisible to the eye. These appeared to breed in any drop of stagnant water, and the question of the spontaneous generation of these microor ganisms raged for two centuries. [212] BOYLE, Robert British physicist and chemist Born: Lismore Castle, County Waterford, Ireland, January 25, 1627
[212] BOYLE
BOYLE [212] Robert Boyle was born into the aris tocracy (as the fourteenth child and sev enth son of the earl of Cork) and was an infant prodigy. He went to Eton at eight, at which time he was already speaking Greek and Latin, traveled through Europe (with a tutor) at eleven, and at fourteen was in Italy studying the works of Galileo [166], who had just died, and finding himself also influenced by his reading of Descartes [183]. His private tutoring saved him from exposure to the didactic Aristotelianism that still vic timized most universities. While in Geneva he was frightened by an intense thunderstorm into a de voutness that persisted for the rest of his life. He never married. Back home in 1645, Boyle found his father dead and himself with an indepen dent income. He kept out of the English Civil War and eventually settled at Ox ford in 1654 and took part in the peri odic gatherings of scholars tackling the new experimentalism made fashionable by Francis Bacon [163] and dramatic by Galileo. It was called the Invisible Col lege, but in 1663 after King Charles II had been restored to the throne the asso ciation of scholars received official recog nition and a charter and became known as the Royal Society. Its motto was “Nullius in verba” (“Nothing by mere authority”). Boyle’s interest in experimentation still represented an odd innovation in science. Most scholars were still suspicious of this. The Dutch-Jewish philosopher Ben edict Spinoza corresponded with Boyle and tried to convince him that reason was superior to experiment. Fortunately Boyle disregarded the gentle Spinoza. In 1657 Boyle heard of the experi ments of Guericke [189] and set about devising an air pump of his own. This he accomplished successfully with the help of a brilliant assistant, Robert Hooke [223]. His pump was an improvement upon Guericke’s and for a while a vac uum produced by an air pump was called a Boylean vacuum. Boyle was one of the first to make use of an evacuated, hermetically sealed thermometer. He also made use of an evacuated cylinder to show, for the first time, that Galileo was actually correct in maintaining that in a vacuum all objects fall at the same velocity. A feather and a lump of lead, in the absence of air resis tance, land together. Then, too, he was able to demonstrate that sound (the ticking of a clock) could not be heard in a vacuum but that elec trical attraction could be felt across one. All this led him to experiment with gases. He was the first chemist to collect a gas. Further, he discovered in 1662 that air was not only compressible but that this compressibility varied with pres sure according to a simple inverse rela tionship. If a quantity of gas was put under doubled pressure (by trapping it in the closed end of a seventeen-foot tube shaped like a J and adding more mercury in the long open end) its vol ume halved. If pressure was tripled the volume was reduced to a third. On the other hand if pressure was eased off the volume expanded. This inverse rela tionship is still referred to as Boyle’s law in Great Britain and America; in France it is credited to Mariotte [203]. Because the compressibility and expansibility of air in response to the force upon it was reminiscent of the coiled metal springs then being studied by Hooke, Boyle re ferred to it as the “spring of the air.” The most significant conclusion drawn from this experiment was that since air was compressible, it must be composed of discrete particles separated by a void. The compression consisted of squeezing the particles closer together. Hero [60] had suspected this fifteen centuries ear lier, but where Hero faced hordes of the oretical philosophers who scorned exper iment, Boyle was part of a growing experimentalist school. Boyle was in fluenced by the writings of Gassendi [182] and his experiments made him a convinced atomist. Atomism was to gain momentum steadily from that time on; after two thousand years the views of Democritus [20] prevailed. Boyle’s experiments on gases were also important because he here initiated the practice of thoroughly and carefully de scribing his experiments so that anyone
[212] BOYLE
RAY [213] might repeat and confirm them—a habit which became universal in science, and without which progress would have re mained at a creep. Boyle had much of the alchemist about him. He believed in the transmuta tion of gold and, indeed, was instru mental in persuading the British govern ment in 1689 to repeal the law against the manufacture of gold, not because it was a useless law (which it was) but be cause he felt the government should take advantage of any gold that was formed and should encourage scientists to form it.
Even so, Boyle transformed alchemy into chemistry in 1661 with the publica tion of The Sceptical Chemist. In it he abandoned the Greek view that made the elements mystical substances of a nature deducible from first principles. Instead he suggested that an element was a ma terial substance and that it could be identified only by experiment. Any sub stance that could not be broken down into still simpler substances was an ele ment. Furthermore two elements could be combined into a compound and then obtained once again out of that com pound. This does not mean he aban doned the old elements. He just wanted them established experimentally rather than intuitively. With this book, Boyle divorced chemistry from medicine and established it as a separate science. Boyle was the first to distinguish be tween acids, bases, and neutral sub stances, studying them by means of the color changes of what we would now call acid-base indicators. He showed that water expanded when it froze and, in deed, began to expand a little before it froze.
He also came within a hair of being the first discoverer of a new element (in the modern Boylean sense). In 1680 he prepared phosphorus from urine. How ever, some five to ten years before that, Brand [216] had preceded Boyle in the discovery. There was fierce controversy
had first discovered phosphorus, largely because investigators held discoveries se cret. Boyle maintained strongly that all experimental work should be clearly and quickly reported so that others might repeat, confirm, and profit. This has been an accepted tenet of scientific research ever since, and when industrial or mili tary security interferes with publication it cannot help but harm the cause of sci ence.
In the sense that Boyle applied the philosophy of experimentalism to the study of material substances and the changes they could be made to undergo, he might be considered the father of chemistry. The reform was not thorough going, however, and was not to become so until the time of Lavoisier [334] a century later; and it is the latter who more properly deserves the honor of paternity. Boyle’s interest in religion grew with age. He learned Hebrew and Aramaic for his biblical studies. He wrote essays on religion and financed missionary work in the Orient. In 1680 he was elected president of the Royal Society but could not accept because he disapproved of the form of the oath. He also repeatedly re fused offers of a peerage. Through his will he founded the Boyle Lectures, not on science but on the defense of Chris tianity against unbelievers. [213] RAY, John English naturalist
vember 29, 1627 Died: Black Notley, January 17, 1705
The son of a blacksmith, Ray never theless made his way through Cam bridge, obtaining his master’s degree in 1651. He stayed on as a lecturer. He had a passion for natural history and would ride for many miles through the countryside, observing and collecting plants. In 1660 he published a scientific description of plants growing near Cam bridge. But then Charles II was restored to the British throne, the land’s religious climate changed, and Ray had to leave the university in 1662 because of his re fusal to take the proper oaths. He then conceived the notion of en gaging in travel and preparing a descrip- Download 17.33 Mb. Do'stlaringiz bilan baham: 
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