The invention of the compound (twin lens) microscope sometime at the end of the sixteenth century or the beginning of the seventeenth, has been ascribed to the Dutch spectacle maker, Hans Jansen. The first great improvement was due to Robert Hooke who in 1665 replaced the eye piece with the twin-lens telescope eyepiece designed by Christaan Huygens . Hooke’s three-lens microscope is the basis for modern instruments. Because of chromatic aberration, which creates a variation of lens focal distance with wavelength, early compound microscopes could not equal the performance of the single, small lens used by the Dutch microscopist , Antonie van Leeuwenhoek. About 1800, achromatic lenses for microscopes became available and a lens design which resolved the problem of spherical aberration for microscopes was developed by Lister in 1830. A general theory of lens design was published in 1841 by Karl Friederich Gauss and many of the remaining limitations (spherical aberration, coma, etc.) were eliminated during 1870 - 1888 by the lens designs introduced by Ernst Abbe
Hans Jansen, a Dutch lensmaker in Middleburg, Holland, or his son, Zacharias, is usually given credit for the invention of the microscope about 1595. Earlier drawings of lens combinations do exist, but are impractical |
Robert Hooke (1635 -1792) was born on the Isle of Wight where his father was a curate. He met Boyle at Oxford and first worked as his assistant. In 1635 he was appointed to a professorship at Gresham College in London where he remained for 30 years. There is no known likeness of Hooke; he was described as a "lean, bent and ugly man". He worked in mechanics, astronomy, and combustion. In optics, Hooke made an important series of microscope observation, was the first to build a Gregorian telescope, discovered diffraction, and was the first to describe thin film phenomena. He was the deputy to Wren in the rebuilding of London following the great fire of 1666; his task as city surveyor was to arrange for the rebuilding of houses. Hooke was one of the principal objects of Newton's animosity. Hooke claimed, with considerable justification, that he had suggested the inverse square law of gravitational attraction to Newton. |
Christaan Huygens (1629 - 1695) is said to be less well known in his native Holland than his father, Constijn, a gifted poet and brilliant figure in the literary history of the Netherlands. Rembrandt, Hals, Spinoza and Descartes were family friends. The last had a profound influence on Huygens and drew him into mathematics and science. His astronomical discoveries, using a telescope based on improvements he introduced, had already made him famous when he went to Paris in 1665. He became a founding member of the French Academy and was granted a pension and an apartment. Most of his life thereafter was spent in Paris, except for a period in which he was forced from France by anti-Protestant emotion and for two years which he spent in England. He did meet with Newton; their conversations were not recorded. However, given his poor English and Newton’s temperment, it is not believed that their meetings had any significant outcome. |
Antonie van Leeuwenhoek (1632 - 1723) was a successful Delft haberdasher and dry goods merchant who devoted himself to the hobby of lens grinding and microscopy. In 1673 he began corresponding with the English Royal Society which published 375 of his papers over the next fifty years. His single tiny lens microscopes had magnifications of up to 300. Although they were difficult and tiring to use they were superior to the contemporary compound microscopes. He made hundreds of his instruments and gave many to his famous visitors, but only a handful have survived. |
Karl Friederich Gauss (1777-1855), born to a poor family in Brunswick, Germany, was supported through the university by his patron, the Duke of Brunswick, became a professor at Gottingen and one of the greatest mathematicians of all time, contributing widely to mathematical theory. He also directed an astronomical observatory, made contributions to electromagnetism, geodesy, and gravitation. His theory of lenses ("gaussian optics") provided the mathematical basis for optical imaging theory. |
Joseph Jackson Lister (1786 - 1869) was an English Quaker wine merchant and amateur microscopist who developed an improved lens system for microscopes in 1830. (Although achromatic telescope lenses had been available for decades, the small size of microscope lenses had made them impossible to correct.) Lister developed the spaced system of lenses which both corrects chromatic aberration and reduces spherical aberration. With this instrument, Lister was the first to observe the forms of mammalian blood cells. He was elected to the Royal Society. Lister’s son, Joseph Lister, the founder of antiseptic surgery, was trained in microscopy by his father. |
Ernst Karl Abbe (1840 - 1905), born in Eisenach, was a professor of mathematics and physics and director of the observatory at the University of Jena. He joined the Carl Zeiss optical company in 1866. His success in providing a scientific basis for microscope design led to the production of microscopes of unequaled capabilities, some of which are not matched by modern instruments. In 1876 he was made a partner in the firm and after Zeiss’s death in 1888, Abbe purchased the heir's interest in the business. Then he turned ownership over to a foundation. Abbe was a social reformer who introduced worker benefits in the firm which were revolutionary in his time. The company grew explosively due to Abbe's accomplishments in the design of optical and photographic equipment and due to the sponsorship of the Prussian government which recognized their military importance. |
A Dutch eyeglass maker, Hans Lippershey, has been given credit for the invention of the telescope in 1608; when he offered it to the government for military use, they required that it be converted to binocular form. By 1610, Galileo announced the telescopic observations of the moon and planets which signaled the end of the Ptolemaic theory of the heliocentric solar system. Galileo’s telescope was a simple refractor, employing two lenses in a tube. Keppler invented the form of the refracting telescope which is the basis for modern refractors; it has a convex lens placed in back of the focus. The reflecting telescope invented by Isaac Newton used an on-axis planar mirror to move the focus of the parabolic reflector to a point outside the light collecting cylinder; reflector telescopes avoid the problem of lens chromatic aberration which affect refractors. Variations of the Newtonian reflector in which the light was reflected back through a hole in the primary mirror were invented by James Gregory in 1663 and by Cassegrain in 1672. A lens design which resolved the problem of chromatic aberration for refractor telescope was discovered in 1733 by Hall but kept secret until it was uncovered and used commercially in 1759 by John Dolland and his son. A third type of telescope, which uses a spherical mirror and a correcting lens, was invented in 1930 by Bernhard Schmidt. The Schmidt telescope serves astronomy as a wide angle camera.
Hans Lippershey (1570-1619), a native of Wesel, Germany who had settled in the Netherlands, applied for a patent for the telescope in 1608. At least two other Dutch spectacle makers made telescopes about the same time, and there were rumors of some such sort of magical device during the 16th century. Nevertheless, Lippershey was the first to describe the telescope in writing. He was paid handsomely by the government to construct several telescopes, but the patent was denied because it was felt that it could be not kept secret. Certainly, within a short time, three-power telescopes were being made and sold by Parisian eyeglass makers. |
Galileo Galilei (1564 - 1643) was the oldest of seven children born to a gifted Pisan composer and mathematician. As an impoverished student, he turned from medicine to mathematics and science, and was known for both brilliance and trouble-making. He began his career as a professor in the University of Pisa, but was soon in conflict with the authorities and was forced to transfer to Padua. He never married but his mistress provided him with three children. He was always in financial difficulties of one sort or other and because he could not afford dowries for his illegitimate daughters he had them placed in convents. In 1609 Galileo learned of the invention of the telescope, built a three power instrument, which he quickly improved to eight, twenty and then thirty power. These were the most powerful instruments of his time and with them he made the discoveries that established Copernican system. |
(Sir) Isaac Newton (1642 - 1727) occupies such a large niche in the history of science and mathematics that he now appears as an Olympian, god-like, figure. In fact, however, he was a man subject to acute anxieties that led him to defend his work in such an irrational and furious manner that his friends questioned his sanity (he did suffer a series of nervous breakdowns) and put him in a series of vicious conflicts with such important scientists as Robert Hooke, John Flamsteed (the royal astronomer) and Gottfried Leibniz. Newton’s paranoia is often ascribed to the fact that his father died before his birth and that at the age of two his mother remarried and left him with his grandmother. His work on color phenomena led him to conclude that light consists of distinct particles (of different sizes) with immutable refractive properties and that an achromatic lens was impossible; thus he was led to the invention and construction of the reflecting telescope in 1670. (Shown above). However, for a century, problems in mirror grinding and in maintaining an untarnished surface prevented the use of reflector telescopes. |
James Gregory (1638 - 1675), born in Aberdeen, Scotland was a professor of mathematics at the University of St. Andrews (1669 - 1674) and later at the University of Edinburgh (1674 - 77). He left St. Andrews, writing that his salary was not paid and that students "were violently kept from me, contrary to their own and their parents wills, the masters persuading them that their brains were not able to endure it." Gregory was the first to publish a proof of the fundamental theorem of the calculus and letters show that he was the first to discover Taylor's theorem. Gregory also discovered the diffraction grating; he used a bird’s feather! In order to build an observatory at St. Andrews he stood outside the church in his hometown, Aberdeen, and took up a collection. |
N. Cassegrain, a French scientist, proposed the telescope design which bears his name in 1672. Nothing else is known about him. One hundred years later, Jesse Ramsden, an English instrument maker who rose from poverty to membership in the Royal Society, discovered that the Cassegrain design may be used to reduce spherical aberration using a paraboidal reflector and a hyperboloid for the secondary reflector. Microwave reflector antennas often employ the Cassegrain design, with the feed horn between the primary and secondary reflectors. |
Chester More Hall (1703 - 1771) was an English barrister and amateur mathematician who, like Euler, became convinced from the fact that the eye is achromatic that an achromatic lens could be built. He experimented with different types of glass until he found the correct combination of flint and crown lenses in 1730. Although he later appeared unconcerned by priority claims, he did attempt to keep the discovery secret by contracting the construction separately to two different firms; however, they subcontracted to the same lens maker, George Bass, who realized what was being built. |
John Dolland (1706 - 1761) was the son of Huguenot silk weavers who set up an optical business in London with his son. By 1759, Dolland learned the secret of the achromatic lens (from George Bass, it is believed), patented the design, received a medal from the Royal Society and began commercial production which made him wealthy. When it was learned that Hall had invented the achromatic lens, Dolland's patent was contested, but the British court upheld his rights |
Bernhard Schmidt (1879 - 1935) was born in Estonia, studied in Germany, and worked as an optical technician at the Bergedorf Observatory, Hamburg. In 1930 he invented the telescope which is named for him. It uses a spherical mirror, not a paraboidal reflector, and employs a correcting plate at the telescope aperture to compensate for spherical aberration, thus it is a combination reflector-refractor system. The Schmidt-Cassegrain telescope is the most popular among amateur astronomers because of its compact design and large aperture and because the optics are completely enclosed . |
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2008年11月23日 星期日 下午 11:53
some dispute exists over whether eyeglasses originated in the Far East or in the West: it appears that the eyeglasses used by the Chinese were for adornment or supposed magical powers and contained colored glass, not correcting lenses. Roger Bacon, the medieval champion of experimental science, made the first recorded reference to the magnifying properties of lenses in 1262. Eyeglasses appeared first in Florence about 1280 and their use spread rapidly. (Their invention is traditionally assigned to Alessandro di Spina). A correct explanation of their operation, however, did not appear for centuries until 1604 with the publication of the work of the astronomer Johannes Kepler. In 1784 Benjamin Franklin invented bifocals. In his invention the two lens sections were held by the frame; one hundred years later a version with the lenses cemented together was invented. Bifocals with the sections fused together were not invented until 1908. In 1827, George Airy introduced the use of a cylindrical lens to correct astigmatism. As for contact lenses, some believe that the sketches made by Leonardo da Vinci about 1508 were intended to indicate contact lenses, and contact lenses were suggested and sketched by René Descartes in 1636. The first contact lenses to have been worn were invented by the physiologist Adolf Fick in 1887, and the plastic contact lens was originated by Kevin Tuohy in 1948. Soft lenses did not appear until the 1970’s.
Roger Bacon (1220 - 1292) was a young lecturer at Oxford who became preoccupied with the idea of experimental studies. He carried out some experiments with lenses and mirrors and described the principles of reflection and refraction, but his great contribution was his insistence on systematic observation and experiments and he is regarded as a forerunner of modern science. He joined the Franciscan order at age 33. About 1266 he applied for papal permission to write a book about the positive effects of experimental methods; he was enjoined to send the book secretly. Without the knowledge of his superiors he completed the work, but the pope’s death in 1268 ended his hope of putting experimental science into the curricula of the universities. Bacon was imprisoned for two years (1277 - 1279), it is believed, by the Franciscan order for "novelties" in his teaching but continued to write aggressively until his death |
Johannes Kepler (1571 - 1630) born in a small German town, was the son of a mercenary soldier. His mother was the daughter of an innkeeper. He received a university scholarship, became an astronomer and rose to the position of imperial mathematician in the court of the Holy Roman emperor. Kepler was among the few to accept the Copernican heliocentric astronomy and he discovered the laws of planetary motion which set the path for Newton’s theory of gravitation. In the course of his astronomical investigations he provided a correct explanation of vision and the functions of the pupil, cornea and retina and after more than three centuries gave the first correct explanation of how eyeglasses work. Kepler lived during the ravages and horrors of the Thirty Years War (1618-1648). At one point he had to rush home to save his mother from death at the stake after she had been accused of witchcraft; his gravesight was lost in the turmoil of the war. |
Benjamin Franklin (1706 - 1790), whose history we all know, was an inventor, scientist, educator, writer, printer, publisher, editor, politician, statesman, diplomat, and postmaster. He helped establish a fire company, a library, an insurance company, an academy, and a hospital. He created a charitable trust which is still in operation. His inventions included the lightning rod, a stove, a musical instrument (the armonica), the flexible catheter, watertight bulkheads for ships and, of course, bifocals. |
(Sir) George Biddell Airy (1801 - 1892) the British Astronomer Royal from 1835 to 1881, was the first to use a cylindrical lens to correct (his own) astigmatism. Airy made other contribution to optics and the diffraction pattern of a circular aperture, which he derived, is named for him. Airy played a peculiar role during the famous 1847 discovery of Neptune through the calculations of orbit perturbations. He (and other British astronomers) failed to act promptly to use the calculations of Adams. As a result, the planet was discovered by the German astronomer, Galle, using the calculations of the Frenchman, Le Verrier. When Adams had gone to see Airy, he was turned away because Airy was at dinner (at three in the afternoon)! |
Adolf Eugen Fick (1829 - 1901) was a renowned German physiologist whose name is attached to the law which governs diffusion phenomena and to a technique for measuring cardiac output. He was one of the first to actually experiment with contact lenses on animals and then, finally, fit contact lenses to human eyes. | | The history of optics and optical devices begins in ancient Greece; the comic writer Aristophanes described the reflection of the sun’s rays. Democritus and Aristotle speculated about the nature of vision. The story of Archimedes focusing the sun’s rays to win a battle for Syracuse in 213 BC is only a legend, reported centuries later, but in the Roman Empire, the philosopher, statesman and tragedian, Seneca noted the magnification of objects seen through water-filled transparent vessels, and his friend, the Emperor Nero may have been the first to use a monocle, employing an emerald lens to view events in the coliseum. The Alexandrian astronomer and mathematician, Ptolemy measured the refractive effects of water and discussed the refractive effects of the atmosphere. At the beginning of the second millennium, the remarkable Persian, Alhazan, solved problems of reflection and refraction and was the first to explain that vision was the result of light coming from an object into the eye..
Aristophanes (450? - 388? BC) the Rabelaisan writer of early Greek comedy, lived during the turbulent period of the Peloponnesian War. His comedies are filled with course, outspoken abuse and satire of prominent individuals. In Clouds, an attack on the educational theories of the radical intellectual Sophists, a character reflects the sun’s rays to secretly melt an I.O.U. (written on a wax tablet). Aristophane’s plays are still being produced after 2,500 years, the most popular being Lysistrata, a comedy in which the women of Greece unite in a sex-strike to force their husbands to agree to peace. |
Democritus (460 - 370 BC) is known only by the surviving fragments of his works; he is said to have been a wealthy citizen of Thrace (modern Bulgaria, for the most part). His place in the history of Physics rests upon his conceptions of the Void and of eternal, indivisible, infinitesimal atoms. He made the first attempt to explain perception and color; his theory was that sensation was caused by the size and shape of atoms, and that color was due to such properties as the roughness of the constituent atoms. |
Aristotle (384 -322 BC) was a son of the Macedonian court physician. He was sent to Athens to study, later founded a school of philosophy there, and for a while was tutor to Alexander the Great. When his works were translated into Latin during the 12th and 13th centuries, they exerted a profound influence on European thought. Aristotle was concerned by questions of perception, and rejected the Euclidian theory that vision was solely due to rays emanating from the eyes and "touching" the object. |
Archimedes (290? - 212? BC), the outstanding mathematician and inventor of the ancient world, was born and spent most of his life in Syracuse, the great city/state of Sicily. He was on close terms with the king, and participated actively in the defense of the city against the Romans, inventing and building war machines. He was killed when the city was finally taken and sacked. Archimedes was very much involved in catoptrics (reflections from surfaces) and in refraction, but his writings in this field are lost, and his mathematics papers were not translated into Latin until the 16th and 17th centuries when their appearance had a significant effect upon the development of mathematics. |
Lucius Annaeus Seneca (4 BC - 65 AD) managed to survive 69 years in the midst of the intrigue and murder at the center of Roman imperial power. Nearly killed by Caligula, exiled for adultery by Claudius, tutor and favorite of Nero, he was finally ordered to commit suicide after being implicated in a plot against his former student. His writings include a number of philosophical works (he was a Stoic) and a series of revenge tragedies. His place here is due to the fact that he noted and wrote about the magnifying effects of liquids in transparent vessels. |
Nero (Nero Claudius Caesar Augustus Germanicus) (37 - 68) became Emporer of Rome at the age of 17 as the result of successful series of poisonings by his mother, Agrippina. His subsequent megalomaniac artistic pretensions, extravagances and misrule led to his eventual overthrow, death, and traditional infamous reputation. His place in a history of optics is due to the circumstance that he used an emerald (the first monocle) while watching combats in the arena. |
Ptolemy (Claudius Ptolemaeus) (85 - 165) propounded the geocentric system which prevailed for the next 1400 years. Nothing is known about his life and he has no biography. Only one of the five volumes he wrote on optics has survived. He dealt with refraction and obtained the small angle approximation to Snell’s law, concluding that the ratio of the angles of incident and refracted light were constant.. He also discussed the refraction of starlight by the atmosphere but held to the theory that vision is due to rays emitted from the eye touching the object . |
Alhazan (Abu Ali Hasan Ibn al-Haitham) (965 - 1040) was one of the most famous of the Arab scholars and those of his 200 works which were translated had great influence when they became available in medieval Europe. He was born in Basra, traveled widely, and lived in Egypt. It is said that when he could not satisfy the Caliph’s request that he find a way to control the Nile floods he feigned madness until the Caliph died. His work in optics included research on reflections from spherical and parabolic mirrors. He disproved Ptolemy’s law of refraction and disagreed with his theory of vision. He also discussed atmospheric refraction, explained the increase in apparent size of the sun and moon near the horizon, and attempted to measure the height of the atmosphere. | |