Biographical encyclopedia
Download 17.33 Mb. Pdf ko'rish
|
|
111 [175] HELMONT
WENDELIN [176] the London College of Physicians, was destroyed in the Great Fire of 1666. [175] HELMONT, Jan Baptista van Flemish physician and alchemist
December 30, 1635, or 1644 Helmont, the scion of a noble family, obtained his medical degree in 1599 at the University of Louvain and practiced without charge. He lived in troubled times, for Spain was trying to suppress rebellion in the Netherlands, and was doing so ruthlessly. Like Paracelsus [131], by whom he was much influenced, he was interested in alchemy and given to mysticism. Hel mont searched for the philosopher’s stone and tried to fuse chemistry and religion into something that was not quite either. On one occasion, at least, that got him into difficulties. He main tained that saintly relics displayed their effects through magnetic influence. For ascribing earthly causes to divine phe nomena, he got into trouble with the In quisition in 1634. He was very emphatic about the “phi losopher’s stone,” which he claimed he had seen and used. He also believed in “spontaneous generation”; that is, the development of living organisms from nonliving surroundings. He declared that mice could arise from dirty wheat, for instance. He denied transmutation of metals, however. In one respect he was unusually con servative, for he abandoned Paracelsus and the alchemical notions of mercury, sulfur, and salt as the basis of solid sub stances. Instead, he moved all the way back to Thales [3], Helmont, like the Greek philosopher, believed that water was the basic element of the universe. It is symptomatic of the new era, however, with new quantitative methods gaining favor and the Scientific Revolution well under way, that Helmont tried to prove his case by experiment. He grew a willow tree in a weighed quantity of soil and showed that after five years, during which time he added only water, the tree had gained 164 pounds while the soil had lost only two ounces. From this he deduced that water was converted by the tree into its own substance. Though he was wrong, the ex periment is of crucial importance. For one thing, he was the first to use quanti tative methods in connection with a bio logical problem and is sometimes called the “father of biochemistry” for that reason. Also he did at least prove that it was not from the solid soil that the chief nourishment of plant life was drawn. In another respect Helmont the alche mist was unusually advanced. He was the first to recognize that there is more than one airlike substance; that some of the vapors he obtained in his experi ments are distinct substances, as different in properties from ordinary air as water is. Because vapors, unlike liquids and solids, have no fixed volume but fill any container, he considered them examples of matter in complete chaos and, about 1620, named them so. However, he spelled “chaos” according to its phonetic sound in Flemish, which made it “gas.” This word, ignored at the time, was rein troduced by Lavoisier [334] a century and a half later and has been used by chemists ever since. In particular Helmont studied the gas produced by burning wood. He called this “gas sylvestre” (“gas from wood”) but we now call it carbon dioxide. Ironi cally it is this gas, not water, that is plant life’s chief source of nourishment and Helmont, in interpreting his experi ment with the willow tree, had neglected to consider the air that surrounded it. He had the right answer in the substance that he himself discovered, but he did not know it. Unfortunately Helmont wrote in a very obscure style, so that he was not as influential as he might have been. His writings were not published till after his death, when his son, a friend of Leibniz [233], edited them. [176] WENDELIN, Godefroy Flemish astronomer Born: Herken, near Liège, Bel gium, June 6, 1580 Died: Gent, 1667 112 [177] SNELL
BAFFIN [178] Wendelin was a cleric, as were so many of the astronomers of the time, and was a canon of Toumai. Despite his position in the church, he was a convinced Copemican. He re peated Aristarchus’ [41] attempt to de termine the distance of the sun by ob serving the geometry of the situation at the exact moment of half-moon. His ob servations were more accurate than Aris tarchus’ had been nearly two thousand years before, and his estimate of the sun’s distance was sixty million miles, which was twelve times greater than the earlier value. It was still one-third short of the ac tual distance, but it did give mankind a glimpse at the real size of the solar sys tem, a glimpse that gave way to rela tively clear vision with Cassini’s [209] work half a century later. [177] SNELL, Willebrord van Roijen Dutch mathematician Born: Leiden, 1580 Died: Leiden, October 30, 1626 Snell received his master’s degree in 1608 and succeeded his father as profes sor of mathematics at the University of Leiden in 1613. He is best known for his discovery in 1621 that when a ray of light passes obliquely from a rarer into a denser medium (as from air into water or glass) it is bent toward the vertical. The phenomenon (refraction of light) was known as long ago as the time of Ptolemy [64], but Ptolemy thought that as the angle to the vertical made by the light ray in air was changed, it main tained a constant relationship to the angle to the vertical made by the light ray in water or glass. Snell showed this was not so. It was the sines of the angles that bore the constant relationship. It was only because at small angles the sines are almost proportional to the angles themselves that Ptolemy was deluded. This key discovery in optics was not well publicized until 1638, when Des cartes [183] published it—without giving proper credit to the source. In 1617 Snell had also developed the method of determining distances by trigonometric triangulation and thus founded the mod em art of mapmaking. [178] BAFFIN, William English explorer
1584
Died: off the island of Qeshm, Persian Gulf, January 23, 1622 For a thousand years after Pytheas [39] the Arctic regions slumbered un touched by the curiosity of men from warmer climes. From the ninth to the eleventh centuries the Vikings of Scan dinavia penetrated to Iceland, Green land, and even North America, but these were isolated ventures with no important consequences for Europe as a whole. The voyages of Columbus [121] and the subsequent realization that the land he had discovered represented new conti nents and not old Asia, led to attempts to reach beyond the Americas to the fabled Indies. The route of Magellan [130] south of South America was a kind of Southwest Passage, which worked but was terribly long. The search was on for a shorter Northwest Passage around northern North America. The effort to find the Northwest Pas sage reached an early climax with Wil liam Baffin. In 1612 he served as chief pilot on a ship that explored the south western coast of Greenland. The next year he turned his energies eastward to ward Spitzbergen. In 1615 he was back in Greenland waters and this time he penetrated north ward into the large body of water lying to the west of northern Greenland, a body now known as Baffin Bay. The large island west of the bay is Baffin Is land. Baffin penetrated to within eight hundred miles of the North Pole and no one else was to get closer for two and a half centuries. Baffin’s explorations caused him to doubt the existence of a Northwest Pas sage. He was both right and wrong, since the sea passage does exist but is so choked by ice that it is not a practical route, except perhaps for specially de signed icebreakers. 113 [179] VERNIER
MERSENNE [181] Baffin’s explorations were accom plished with scientific precision. He de termined latitudes and observed tides carefully. His recordings of the orienta tion of the compass needle led to the first magnetic chart. He was the first to try to determine longitude at sea by ob servations of the moon. After these Arctic explorations Baffin made a fatal switch to tropic waters, sur veying areas in and about the Red Sea and the Persian Gulf. He was an em ployee of the East India Company at this time. When the Company allied itself in 1621 with the Shah of Persia against the Portuguese, Baffin found himself in a war. During an attack on Qeshm, an is land at the mouth of the Persian Gulf, Baffin was killed. [179] VERNIER, Pierre (vehr-nyayO French engineer Born: Omans, August 19, 1584 Died: Omans, September 14, 1638
Vernier was the son of a lawyer and a minor government official in a part of France (Franche Comte) that was then ruled by the Hapsburg kings of Spain. Vernier was a military engineer in the employ of the Spanish king. He was interested in instruments and in particular in devices that would allow one to measure angles or small distances with great precision. Others had worked on the problem before and the idea had existed of dividing a number of intervals of progressively larger size (by small steps) into equal numbers of sub divisions. The measure one wanted would be bound to fall near a sub division on one of the scales and from that the angle or distance could be calcu lated quite precisely. The difficulty lay in devising these many scales with the nec essary precision in the first place. Clavius [152] was one of those who worked on the problem. It occurred to Vernier that only two such scales were necessary, if one was made movable. It could be adjusted against the immovable scale to just fit the angle or the linear measure and then the position of the moving subdivisions against the fixed ones would give the measure to an extra decimal point. Ver nier announced his device in 1631 and immortalized himself for the device has been known as a “vernier” ever since (pronounced “vur'nyer” in English). Since one motive force behind the ad vance of science has been the invention and construction of ever more precise measuring instruments, Vernier deserves mention for that feat alone. [180] CYSAT, Johann Swiss astronomer Born: Lucerne, 1586 Died: Lucerne, May 3, 1657 Cysat, a pupil of Scheiner [173], en tered the Jesuit order in 1604 and later became a priest. He served as professor of mathematics at the Jesuit college of Ingolstadt in Bavaria. He was one of the early users of the telescope and surveyed the sky with one as early as 1611. He studied spots on the sun and was the first to use a telescope to observe a comet. His most notable achievement was the discovery of the Orion Nebula in 1619. [181] MERSENNE, Marin (mer-senO French mathematician
ber 8, 1588 Died: Paris, September 1, 1648 Mersenne was a schoolfellow of Des cartes [183] but, unlike the latter, went on to enter the church, joining the Minim Friars, in 1611. Within the church, Mersenne did yeoman work for science, of which he was an ardent expo nent. He defended Descartes’s philoso phy against clerical critics, translated some of the works of Galileo [166], and defended him, too. Mersenne’s chief service to science was the unusual one of serving as a channel for ideas. In the seventeenth century, long before scientific journals, interna tional conferences, and even the estab lishment of scientific academies, Mer-
[182] GASSENDI
DESCARTES [183] senne was a one-man connecting link among the scientists of Europe. He wrote voluminous letters to regions as distant as Constantinople, informing one correspondent of the work of another, making suggestions arising out of his knowledge of the work of many, and constantly urging others to follow this course of copious intercommunication. He opposed mystical doctrines such as astrology, alchemy, and divination and supported experimentation. As a practi cal example of this belief he suggested to Huygens [215] the ingenious notion of timing bodies rolling down inclined planes by the use of a pendulum. This had not occurred to Galileo, and Huy gens was to take this idea to fruition in a pendulum clock. Mersenne is best known today for the “Mersenne numbers,” numbers produced by a certain formula which, Mersenne said, would yield primes. His reasons for deciding this are not known, but in any case he was wrong; some of the large numbers he maintained to be prime proved not to be. Nevertheless, the Mer senne primes proved to stimulate re search into the theory of numbers. [182] GASSENDI, Pierre (ga-sahn-deeO French philosopher Born: Champtercier, Provence, January 22, 1592 Died: Paris, October 24, 1655 Gassendi, bom of poor parents, stud ied and taught at the University of Aix, where he obtained his doctorate in theol ogy in 1616, but rebelled against its me dieval attitude. His philosophic views served science in two ways. In the first place, like his older contemporary Francis Bacon [163] he strongly ad vocated experiment in science. He came to understand the importance of experi mentation in his reading of Galileo [166] whom he supported even after Galileo’s condemnation by the Inquisition. Secondly he was a convinced atomist and helped bridge the gap between Epi curus [35] and Lucretius [53], whose nineteen-century-old views he strongly supported, and the scientific atomism that was to come two centuries after his time. More specifically, his views strongly affected those of Boyle [212]. He was interested in astronomy, too, describing the aurora borealis in 1621 and giving it its name. Another of his concrete scientific accomplishments was to observe the transit of Mercury in 1631, within five hours of the time pre dicted by Kepler [169]. It was the first planetary transit ever observed. He also dropped a stone from the top of the mast of a moving ship and showed that it landed at the bottom of the mast. The ship did not move from under it. This bore out one of Galileo’s “thought experiments” and disproved the Ptolemaic argument against the earth’s rotation, the one which maintained that if the earth rotated then someone jump ing up into the air would come back to earth far from his starting point. Gassendi vigorously opposed Des cartes’s [183] philosophy and Harvey’s [174] theory of blood circulation. He made up for that in his study of sound, though. He studied its velocity, which he showed to be independent of pitch, thus refuting Aristotle’s [29] contention that high notes traveled more rapidly than low notes. Gassendi published biographies of Peurbach [118], Regiomontanus [119], Copernicus [127], and Tycho Brahe [156], and it might be mentioned as a link between science and literature that among Gassendi’s pupils was the great French playwright Molière. In 1645 he became professor of math ematics at the Collège Royale at Paris. [183] DESCARTES, René (day-kahrt') French philosopher and mathe matician
Born: La Haye, now called La Haye-Descartes (near Tours), March 31, 1596
ary 11, 1650 As was common in his day, when Latin was the language of scholarship, Descartes used a Latinized version of his name for his writings, signing them Ren- 115 [183] DESCARTES DESCARTES
atus Cartesius. It is because of this that Descartes’s system of philosophy is spo ken of as Cartesian and that the com mon system of plotting the curves repre sented by equations (a system Descartes originated) involves Cartesian coordi nates. Nevertheless, Descartes wrote in French rather than in Latin, another in dication of the continuing decline of Latin as the universal language of schol arship in Europe. Descartes’s mother died when he was a year old and he appears to have in herited her ill health. He was troubled with a chronic cough and at school was allowed to remain in bed as long as he wished. (The fact that he was a brilliant student contributed also to the fa voritism.) He retained the habit of doing much of his work in bed for the rest of his life and could well pamper himself in this way for he never married and thus avoided family responsibilities. From the days of his Jesuit education Descartes remained carefully devout. For instance when in 1633 he heard that Galileo [166] had been condemned for heresy, he at once abandoned a book he was writing on the universe in which he accepted the views of Copernicus [127], Instead, by 1644, he had worked out a theory according to which all space was filled with matter arranged in rotating vortices. He considered the earth at rest in the center of a vortex. It was the vor tex, then, that traveled about the sun. This compromise, like that of Tycho Brahe [156], was ingenious but worth less. Nevertheless it was accepted by many scholars until Newton [231] a gen eration later put all lesser theories to flight with his theory of gravitation. Des cartes’s vortices, however, were, in some ways, strangely like Weizsacker’s [1376] vortices three centuries later. After some years in the French army —during which time he was not exposed to actual warfare and found ample time to work out his philosophy—Descartes settled in Protestant Holland. There he remained for almost all his life until at an unlucky moment in September 1649 he succumbed most reluctantly to an in vitation to the Swedish court. The Swedish ruler at the time was Christina, who was anxious to obtain the services of a renowned philosopher in order to glorify her court. (This desire by European royalty for intellectual luster was to become particularly pronounced during the Age of Reason, as the eigh teenth century was to be called.) Unfortunately Christina was one of the most eccentric rulers ever to grace a throne, and her notion of utilizing Des cartes’s services was to have him call on her three times a week at 5 a .
. to in
struct her in philosophy. Visiting the cas tle during the coldest part of a Swedish winter night three times a week was too much for Descartes’s delicate lungs and he was dead of pneumonia before the winter was over. His body, all but the head, was returned to France. In 1809 Descartes’s skull came into the posses sion of Berzelius [425], who turned it over to Cuvier [396], and thus Descartes came home at last. Descartes was a mechanist. Out of ex tension and motion, he would say, the universe could be constructed and he thought it necessary to begin with some incontrovertible fact, something that could be accepted to begin with. In his Discourse on Method, published in 1637, he began by doubting every thing; but this very doubt appeared to him to be the incontrovertible fact for which he searched. The existence of a doubt implied the existence of something that was doubting, hence the existence of himself. He expressed this in the Latin phrase “Cogito, ergo sum” (“I think, therefore I am”). The system he built on this was sufficiently impressive to earn the title sometimes bestowed on him: fa ther of modern philosophy. Descartes applied the mechanistic view even to the human body though not to the human soul, or to God. Basing his conclusions on the work of Vesalius [146] and Harvey [174] (whose work on the circulation of the blood he helped to popularize) he tried to present the purely animal workings of the body as a system of mechanical devices. The mind was outside the body and independent of it, but interacting with it through the
Download 17.33 Mb. Do'stlaringiz bilan baham: 
|