Biographical encyclopedia
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311 [467] DAGUERRE
DAGUERRE [467] night. It occurred to him that he might find a new planet in the neighborhood of the sun, catching it as it passed before the sun’s disc. He began to watch the sun in 1825 with a small two-inch telescope and could not help but note the sunspots. After a while he forgot about the planet and started sketching the sunspots. In 1829 he sold the family business so he could spend his full time on his hobby of sun-watching. For seventeen years, he sketched sunspots on every sunny day—an incredible monument to patience—and in the end he was re warded. By 1843 he was able to an nounce that the sunspots waxed and waned in number according to a ten-year cycle (actually eleven, astronomers have since found). The announcement was ignored until Humboldt [397] mentioned it in his book
considered as initiating modern solar studies. Nor was it long before the work of men such as Lamont [546] showed that the sunspot cycle had its effect on the earth. Despite his preoccupation Schwabe ap parently had time to look elsewhere—oc casionally, at least. In 1831 he drew a picture of Jupiter on which the “great red spot” is clearly shown for the first time.
[467] DAGUERRE, Louis Jacques Mandé (dah-gairO French artist and inventor
Seine-et-Oise, November 18, 1789 Died: Petit-Brie-sur-Marne, near Paris, July 12, 1851 Daguerre’s artistry was intimately con cerned with the theater, for he special ized in painting scenic backdrops. To make the backdrops more entertaining, he created dioramas, consisting of opti cal effects in which real objects were made to blend in with a painted back ground and in which different scenes might be displayed successively—to give an effect, for instance, of changing sea sons. Optical effects have always interested mankind. The camera obscura (Italian for “dark room”) or pinhole camera, had been a much-used device. Sunlight entering such a room or chamber through a small opening could be made to fall on a screen in such a way as to present a sharp image of whatever was outside the room. It wasn’t difficult to in sert a lens in the pinhole in order to make possible a larger opening and more light without affecting the sharpness of the focus. Daguerre grew interested in the possi bility of making the image produced in the camera a permanent one. It was known that light could darken silver compounds, and in fact Ritter [413] had discovered ultraviolet light a quarter century earlier through that effect. In 1829 Daguerre went into partnership with Niepce [384], who had managed to produce images by the action of light some three years earlier but had failed to make the process really practical since exposures took hours. Daguerre carried on and began to use copper plates on which silver salts were deposited. Light was made to focus on that and an image was formed. The light portions of the image darkened the salts, while the shadowy portions left them unaffected. The unchanged salt was dissolved away by sodium thiosulfate (a process that had been suggested by John Herschel [479]) and a permanent image of sorts was left behind. The new advance was reported to the Academy of Sciences in 1839 by Arago [446] and Daguerre was at once ap pointed an officer of the Legion of Honor. The process was tedious (exposures still took twenty minutes) and the results were dim but the notion of a picture painted by sunlight and without the im perfections introduced by human fallibil ity caught on everywhere. The photo graph produced was known as a daguer- rotype, and in the United States, Morse [473] was one of the first to try his hand at the new art. By the 1840s the new technique was being used to record heavenly objects, and men such as Sec- chi [606] were to make it a recognized tool of astronomy. •
[468] MANTELL
DANIELE [470] [468] MANTELL, Gideon Algernon (man-tel') English geologist Born: Lewes, Sussex, February 3, 1790
Died: London, November 10, 1852
Mantell, the son of a shoemaker, stud ied medicine, obtained his degree in 1811 and began a thriving practice in his hometown. His hobby, however, was ge ology and, little by little, that hobby ousted everything else—his medical prac tice, his home, his family. In 1822 his wife noticed some teeth and scattered bones in a pile of stones by the road they were walking along. Man tell studied them and was puzzled by them until, in 1825, he came across teeth of the iguana (a kind of lizard). He then recognized that the fossil teeth he had found were just like those of the iguana, but larger. He named the animal to which the fossils belonged iguanodon (“iguana teeth”). In succeeding years, he found fossil bones of other large animals and de scribed them accurately. It was Owen [539] who, in 1854, reconstructed the ancient animals (more imaginatively than accurately) and named them dino saurs (“terrible lizards”). It turned out that Mantell had discovered no less than four of the broad divisions of these magnificent animals. It was the dinosaurs that, more than anything else in the long past, caught the imagination of the world, convinced peo ple that great animals had existed long before the dawn of humanity, and made them ready to accept the fact of evolu tion despite the thunders of the religious fundamentalists. [469] HALL, Marshall English physiologist Born: Basford, Nottinghamshire. February 18, 1790 Died: Brighton, August 11, 1857 Hall, the son of a cotton manufac turer. was apprenticed to an apothecary, went on to study medicine, and obtained his medical degree in 1812 from the University of Edinburgh. After addi tional education on the Continent, he practiced in Nottingham, moving to Lon don in 1826. Beginning in 1832, Hall studied the quick involuntary motions that result when one touches something unex pectedly hot—the instant withdrawal that follows even before a conscious per ception of heat—and other actions of that nature. This “reflex” action, as he termed it, he attributed, in the 1830s, to nerve impulses to and from the spinal cord. In 1830 he denounced bloodletting as a medical cure-all and helped wipe out that most pernicious practice. [470] DANIELL, John Frederic English chemist Born: London, March 12, 1790 Died: London, March 13, 1845 Daniell, the son of a lawyer, was edu cated privately and began his career by working in a relative’s sugar-refining fac tory. His early researches were suffi ciently impressive to procure him elec tion to the Royal Society when only twenty-three. In 1831 he was appointed the first professor of chemistry at King’s College in London. He invented several scientific instru ments, including (in 1820) a hygrometer for measuring humidity. He was inter ested in the physics of the atmosphere and greatly improved hothouse manage ment by stressing the importance of moisture. In 1831, he devised a pyrom eter for the measurement of heat. He is best known, however, for his work in electrochemistry, his interest having been aroused by the work of his good friend Faraday [474], Volta’s [337] battery had the defect of rapid diminu tion in current. In 1830 Sturgeon [436] had amalgamated the zinc used (he al loyed it with mercury) and produced a battery of longer life. What was needed, however, was a battery yielding a con stant current over a considerable length of time.
In 1836 Daniell succeeded, producing the Daniell cell, of copper and zinc. This 313 [471] MÖBIUS
MORSE [4731 was the first reliable source of electric current, though great work had been done by men such as Davy [421] with the rickety electrical sources of Volta’s time. Daniell died while attending a meeting of the council of the Royal Soci ety.
[471] MÖBIUS, August Ferdinand (moi'bee-oos) German mathematician
November 17, 1790 Died: Leipzig, Saxony, September 26, 1868 Möbius was the son of a dancing teacher and, through his mother, was a descendant of Martin Luther. He studied at the universities of Leipzig, Göttingen, and Halle, and was at first intent on en tering law. Under the influence of Gauss [415], however, he turned to mathe matics and astronomy. In 1816 he joined the faculty of the University of Leipzig and in 1844 he was appointed director of the Leipzig Observatory. He is more famous for his mathematical work. In particular he is remembered for the Möbius strip, a paradoxical figure con structed by joining the two ends of a flexible strip after giving it a half twist. The resulting construction has but one edge and one side. This made Möbius, who presented the construction in 1865, one of the founders of topology, the branch of mathematics that deals with those properties of figures that are not altered by deformations without tearing. [472] PEACOCK, George (peeTcok) English mathematician
1791
Died: Ely, November 8, 1858 Peacock, the son of a curate, was educated at home. He entered Cam bridge in 1809 and took second place in mathematics on his graduation. He ob tained his master’s degree in 1816. His chief claim to fame is that he, along with Babbage [481] and John Herschel [479] finally broke the hold of the nomenclature of Newton [231] on English mathematics. Because of a foolish nationalist distaste for the no menclature of Leibniz [233], which was superior, English mathematics had lagged and decayed for over a century. Peacock also wrote a text on algebra, published in 1830, which went partway at least toward the establishment of an abstract algebra, divorced from the com mon algebra that was the servant of arithmetical calculations. [473] MORSE, Samuel Finley Breese American artist and inventor
Boston), Massachusetts, April 27, 1791
April 2, 1872 Morse, the son of a minister, gradu ated from Yale in 1810 and went to En gland to study art, rather against the wishes of his parents. He remained there during the War of 1812, a matter that in those easygoing days didn’t seem to bother anyone. At home he achieved considerable fame as an artist, but little wealth. He was disappointed when Congress rejected his offer to beautify the Capitol. He unsuccessfully entered politics as a member of the Native American party (a group of bigoted anti-Catholics and anti-immigrants). During the 1830s he caught the fever of electrical experimentation from C. T. Jackson [543], a fellow passenger on an ocean voyage. Morse decided to build an electrical telegraph but found he could not, for he had little knowledge of elec tricity. He met Henry [503] by accident and Henry helped him without stint, an swering all his questions. Morse then began to try to enlist support for the construction of a telegraph, and here, as a man of pertinacity and bulldog deter mination, he displayed his real talents. He obtained a patent in 1840. then managed to persuade and bully a most reluctant Congress into appropriating $30.000 in 1843—by a margin of six votes—to build a telegraph line over the
[474] FARADAY
FARADAY [474] forty-mile stretch from Baltimore to Washington. It was built in 1844, and it worked. Morse’s first message was “What hath God wrought?” sent in a code of dots and dashes that he had orig inated and that is still called the Morse code.
Morse went on to reveal a meanness of soul, for he never acknowledged Henry’s help and, indeed, during pro longed litigation with Jackson over prior ity, tried to maintain that Henry had never helped him. Henry, testifying at the trial, was easily able to prove the contrary. Nevertheless, Morse grew rich and Henry did not. During the Civil War, Morse, though a Northerner, sympathized with the South, thanks to his racist principles and his belief that Negro slavery was justified. However, he met with great fame, and many honors during his life time and when the Hall of Fame for Great Americans was first opened in 1900 on the campus of New York Uni versity, Morse was made a charter member. The authentically great Ameri can, Henry, was not elected until 1915. [
] FARADAY, Michael English physicist and chemist Born: Newington, Surrey, Septem ber 22, 1791 Died: Hampton Court, Middlesex (now part of Greater London), August 25, 1867 Faraday was one of the ten children of a blacksmith who moved with his brood to London. It is a rare laboring family with ten children that is affluent, so there was no question of an education beyond reading and writing for young Faraday and he was apprenticed to a bookbinder in 1805. This, as it happened, was a stroke of luck, for he was exposed to books. Officially he was concerned only with the outside, but he could not help opening the books as well, working his way through the electrical articles in the En cyclopaedia Britannica, for instance, and reading Lavoisier’s [334] great textbook of chemistry. Faraday’s second stroke of luck was that his employer was sympathetic to the young man’s desire for learning and al lowed him to read the books and to at tend scientific lectures. In 1812 a customer gave Faraday tickets to attend the lectures of Humphry Davy [421] at the Royal Insti tution. Young Faraday took careful notes, which he further elaborated with colored diagrams. He ended with 386 pages, which he bound in leather and sent to Banks [331], president of the Royal Society, in the hope of getting a job that would bring him into closer con tact with science. Getting no answer he sent others to Davy himself, along with an application for a job as his assistant. Davy was enormously impressed, as much by the flattery implicit in the ges ture as by the clear ability of the young ster. He did not oblige the young man at once but when he fired his assistant for brawling, he offered Faraday the job. In doing so, he followed the advice of a trustee of the Royal Institution who said, “Let him wash bottles. If he is any good, he will accept the work; if he refuses, he is not good for anything.” Faraday accepted the offer in 1813, at the age of twenty-two—at a salary smaller than the one he had been earn ing as a bookbinder—and washed bot tles.
Almost at once Davy left for his grand tour of Europe and took Faraday with him as secretary and valet. This gave Mrs. Davy a chance to treat Faraday with scorn, as a servant; something Davy, to his discredit, did not prevent but which Faraday bore with humility. The trip also gave Faraday the chance to see Napoleon (now rapidly losing to the rest of Europe) at a distance, for what that was worth. More important, he met such men as Volta [337] and Vauquelin [379]. _
worthy of his master. He virtually lived in and for the laboratory, then and later, never using a collaborator or assistant. Little by little Davy came to realize that his protégé would eventually outshine himself and he grew bitter and resentful. This was particularly so after Faraday
[474] FARADAY
FARADAY [474] pointed out some flaws in Davy’s inven tion, the miner’s safety lamp, though he did so under oath in a court of law where equivocation was impossible—at least for a man like Faraday. Faraday became director of the labo ratory in 1825 and in 1833 the onetime bookbinder’s apprentice became profes sor of chemistry at the Royal Institution. He concentrated on his lone researches, refusing an ample income for continuing services as an expert witness in court, and turning down a call to the greater distractions of the University of London. In chemistry Faraday made his first mark in 1823, when he devised methods for liquefying gases such as carbon diox ide, hydrogen sulfide, hydrogen bromide, and chlorine under pressure. He was the first to produce temperatures in the labo ratory that were below the zero mark on the Fahrenheit [254] scale. He may thus be viewed as a pioneer in the modern branch of physics called cryogenics (the study of extreme cold). Here he gave Davy further cause for resentment, for in Faraday’s reports on gas liquefaction, he did not (in Davy’s opinion) give due credit to Davy’s prior work in the field. In 1825 occurred his greatest single contribution to organic chemistry. He discovered benzene, a compound that was to play a key role in Kekule’s [680] development of a means of representing molecular structure. In addition Faraday carried on Davy’s great work in electrochemistry. Davy had liberated a number of new metals by passing an electric current through mol ten compounds of those metals. Faraday named this process electrolysis. He named a compound or solution that could carry an electric current an elec trolyte. The metal rods inserted into the melt or solution he called electrodes, the positive electrode being an anode, the negative one a cathode. All these names, suggested to him by the British scholar, Whewell [487], who also coined the word “scientist” in the 1840s, still exist unchanged and are used constantly in science. In 1832 Faraday further reduced the matter of electrolysis to quantitative terms by announcing what are now called Faraday’s laws of electrolysis. These are (in modem terminology): 1. The mass of substance liberated at an electrode during electrolysis is pro portional to the quantity of electricity driven through the solution. 2. The mass liberated by a given quantity of electricity is proportional to the atomic weight of the element liber ated and inversely proportional to the valence of the element liberated. By valence is meant the combining power of an element. For instance, an atom of sodium or silver will each com bine with only one atom of chlorine, whereas a copper atom will combine with two atoms of chlorine. Sodium and silver are therefore said to have a valence of one, while copper has a valence of two. Now, sodium has an atomic weight of 23, silver of 108, and copper of 64 (using whole numbers). The quantity of electricity that will liber ate 23 grams of sodium will suffice to liberate 108 grams of silver. It will, how ever, liberate only 32 grams of copper (the atomic weight divided by the valence). These laws, which established the inti mate connection between electricity and chemistry, against diehard opposition by people such as Hare [428] and Fechner [520], are easily interpreted in atomic terms; but Faraday, oddly enough, was never an enthusiastic atomist and ig nored atoms whenever possible. The laws also strongly favor the proposition that the electric current was composed of particles (something that Franklin [272] had suggested nearly a century earlier). This particle theory of electricity was not fully developed until the work of Ar rhenius [894] a half century later. Faraday’s laws put electrochemistry on its modem basis. In his honor the quan tity of electricity required to liberate 23 grams of sodium, or 108 grams of silver or 32 grams of copper (that is, to liber ate an “equivalent weight”—a concept named and elaborated by Wollaston [388]—of an element), is called a fara day. Like Coulomb [318], then. Faraday lends his name to a unit measuring quantity of electricity. The two are linked by the fact that 96,500 coulombs
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