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[367] d ’ elh u y ar CHAPTAL [368]
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[367] d ’ elh u y ar CHAPTAL
[368] was fortunate enough to interest an anat omist in his obvious intellect, and that man arranged to have him receive a medical education. Fourcroy obtained his degree in 1780, but found his interest in chemistry. He became a professor of chemistry at the Jardin du Roi in 1784. An excellent and successful teacher, he obtained his chief fame in connection with others. He was one of the first converts to the theories of Lavoisier [334], with whom he collab orated in establishing the new chemical nomenclature. During the French Revolution he was a violent partisan of the radicals, suc ceeding to the seat that had been held by the assassinated demagogue Marat. He helped engineer the temporary suppres sion of the Academy of Sciences, which was suspected of being an aristocratic or ganization. Nor did he use his influence to save Lavoisier. Indeed, his testimony was damaging to his old associate— perhaps deliberately so. Later, however, he used his influence to save other scien tists.
Under Napoleon he served as Minister of Public Instruction and in later lif£ he was the patron of Vauquelin [379], He died on the day Napoleon made him a count. [367] D’ELHUYAR, Don Fausto (del- oo'yahr) Spanish mineralogist Born: Logrono, northern Spain, October 11, 1755 Died: Madrid, January 6, 1833 D’Elhuyar and his older brother, Juan José, studied mineralogy in Germany and became disciples of the theories of Werner [355]. They visited Sweden in 1782, studied with Bergman [315], and visited Scheele [329]. They analyzed a mineral called wolframite, which had been obtained from a tin mine, and in 1783 obtained a new metal from it, called wolfram. The same metal is also called tungsten from the Swedish words meaning “heavy stone.” Scheele had in vestigated tungsten-containing minerals but had missed spotting the new metal. The D’Elhuyar brothers were eventu ally sent to Latin America (then under Spanish domination) to supervise mining there. Fausto’s older brother died in what is now Colombia, but Fausto, hav ing served in Mexico with distinction, lived to return to Spain after Mexico gained its independence. [368] CHAPTAL, Jean Antoine Claude, comte de Chanteloup (shap-tal') French chemist Born: Nogaret, Lozère, June 4, 1756
Died: Paris, July 30, 1832 Chaptal, the son of a small landowner, had a rich physician as an uncle, which was helpful. The young man studied medicine, receiving his medical degree at Montpellier in 1777. Against his uncle’s will, he grew interested in chemistry, though, and obtained a professorship at the University in 1781. He was one of the first to adopt Lavoisier’s [334] new view of chemistry. He was particularly interested in the application of chemistry to industry and, having inherited a large sum from his uncle and having married a wife with a large dowry besides, he had the where withal to establish a plant at Montpellier in 1781 for the first commercial produc tion of sulfuric acid in France. His use fulness was such that both Spain and the infant United States bid for his services (both without success). After the French Revolution broke out he was arrested, in 1793, but he was soon liberated and put in charge of a plant manufacturing gunpowder. The re public did have need of scientists, after all (though they had thought otherwise in the case of Lavoisier), for without the development of new chemical methods France (which was at war with all the surrounding nations) could not have produced the gunpowder she needed and the republic would have been crushed. Under Napoleon, Chaptal was placed in charge of education and was a strong advocate of the writing of science for the layman. He supervised the introduction of the metric system and was eventually
[369] MCADAM
CHLADNI [370] made a count. When Napoleon fell, and the old monarchy returned with Louis XVIII, Chaptal was relieved of his title but was done no other harm. He lost much of his wealth, however, paying the debts his son ran up when he conducted the family firm in a slipshod manner. It was Chaptal, by the way, who, in 1790, suggested the name “nitrogen” for the element Lavoisier had called “azote.” His most important book was Chemis try Applied to the Arts, published in 1807. This was the first book to be devoted specifically to industrial chemis try.
[369] McADAM, John Loudon Scottish engineer Born: Ayr, Ayrshire, September 21, 1756 Died: Moffat, Dumfriesshire, No vember 26, 1836 In 1770, after his father died, Mc- Adam traveled to New York to work for his uncle, who during the war was a well-to-do Tory. McAdam, naturally, was a Tory too and made a comfortable living as agent for the sale of war prizes. Once the peace treaty was signed and the colonies established as an indepen dent power, he returned to Scotland, in 1783.
His true fame began in 1806, when he became paving commissioner in Bristol. He began to push energetically for new and rational principles of paving: mak ing roads out of crushed rock, with proper allowance for drainage, instead of the alternating ruts and mud (depending on whether the weather was dry or wet). There was strong economic motivation for this since the first third of the nine teenth century was the golden age of stagecoaches. After McAdam’s death, Stephenson’s [431] locomotive—traveling on iron rails rather than on paving—killed the coaches. Nevertheless the time was to come when paved roads would carry au tomobiles on rubber tires and that in turn was to send the railroad into de cline. To macadamize is still sometimes used to mean the paving of a road, in honor of McAdam. [370] CHLADNI, Ernst Florens Fried rich (klahd'nee) German physicist
vember 30, 1756 Died: Breslau, Silesia (modern Wroclaw, Poland), April 3, 1827 Chladni, the son of a lawyer, found his own education directed to the law, much against his will. He received his degree from the University of Leipzig in 1782, but when his father died Chladni was able to consult his own interests more freely, and these lay in the direc tion of science. Since he was interested in music and was himself an amateur musician, he began to investigate sound waves mathe matically in 1786. He was the first to work out the quantitative relationships governing the transmission of sound and is therefore called the father of acous tics.
Chladni set thin plates, covered with a layer of sand, to vibrating. The plate vi brated in a complex pattern, with some portions (nodal lines) remaining motion less. The nodal lines retained sand shaken onto them by the neighboring areas that were vibrating. In this way the plates came to be covered with charac teristic sand patterns from which much could be deduced concerning vibrations. The patterns (which are still called Chladni figures) fascinated the audience when they were exhibited before a gath ering of scientists at Paris in 1809. Na poleon had the demonstration repeated for himself. The velocity of sound had already been measured in air by Gassendi [182] and others two centuries earlier, but Chladni went a step further. He filled organ pipes with different gases and from the pitch of the note sounded on those pipes was able to calculate the ve locity of sound in each of those cases. The free vibration of a column of gas determines its pitch, and that vibration depends on the natural mobility of the molecules making it up. The velocity of sound through the gas also depends on the natural mobility of those molecules, so that the velocity of sound in a partic
[371] GALL
OLBERS [372] ular gas can be calculated from the pitch sounded by an organ pipe filled with gas. Chladni invented a musical instrument called the euphonium, made of glass rods and steel bars that were sounded by being rubbed with the moistened finger, and traveled about Europe performing on this instrument and giving scientific lectures. He also had a collection of me teorites and was one of the first scientists to insist that these fell from the heavens, as a number of peasants, who claimed they had seen it happen, had reported. In 1794 he wrote a book on the subject and suggested the meteorites to be the debris of an exploded planet. In the very reasonable Age of Reason of the late eighteenth century, scientists were reluc tant to believe such obviously tall tales, until Biot [404] settled matters at the turn of the century. [371] GALL, Franz Joseph (gahl) German physician Bom: Tiefenbrunn, Baden, March 9, 1758
Died: Montrouge, near Paris, France, August 22, 1828 Gall, the son of a merchant who was of Italian descent, studied medicine at Baden, Strasbourg, and Vienna, obtain ing his medical degree in the last-named city in 1785. He was particularly inter ested in the physiology of the nerves and the brain. He pointed out, quite correctly, that the gray matter was the active and essen tial part of the brain and that the white matter was connecting material. Gall believed that the shape of the brain had something to do with mental capacity and that different parts of the brain were involved with different parts of the human body. In this there was considerable truth. Modern neurologists map the brain in detail, finding one re gion in control of finger movement, an other in control of jaw movements, and so on. Gall imagined he could correlate the shape of the brain with all sorts of emo tional and temperamental qualities and that the shape of the brain could, in turn, be deduced from the superficial unevennesses of the skull. This marks the beginning of the pseu doscience of phrenology, in which a man’s character is supposedly analyzed by feeling the bumps on his head. Gall lectured in Vienna on the subject (charging admission) until 1802, when he was stopped by Emperor Francis I because his materialistic philosophy seemed subversive of religion. (If one re duces evil impulses to the presence of a particular bump on the skull, what be comes of free will?) Like Mesmer [314], a generation be fore him, Gall traveled to Paris (having first made a tour of northern Europe in 1807). In 1808 he presented his theories to the Institut de France. The French, as in the case of Mesmer, appointed a com mittee to look into the matter, and the committee reported unfavorably. Em peror Napoleon I acted to limit his influence in France. (Gall was about the only thing France and Austria agreed on in these years.) This did not stop the favorable recep tion of phrenology among the general public any more than it had earlier stopped the appeal of mesmerism. After Gall’s death his disciples increased the nonsense in phrenology and reduced it to utter folly. As a result the stigma of the quack clings to Gall, and the valuable work done by him tends to be forgotten, as in the case of Mesmer. Gall became a French citizen in 1819. [372] OLBERS, Heinrich Wilhelm Mat thaus (ohl^bers) German astronomer
October 11, 1758 Died: Bremen, March 2, 1840 Olbers, the eighth of sixteen children of a minister, was trained as a physician at Gottingen, graduating in 1780. He practiced medicine in Bremen, but spent his nights in astronomical observations, having converted the upper portion of his house into an observatory. His first love was the pursuit of comets. He worked out a method in 1797 for deter mining their orbits that is still used, and
[373] GADOLIN
HALL [374] he discovered five. One of these, discov ered in 1815, is still called Olbers’ comet. In 1820, after the death of his second wife and of his daughter, he re tired from ordinary pursuits and devoted himself completely to astronomy. He was one of the guiding spirits in the team dedicated to the discovery of the planet in the gap between Mars and Jupiter. Although he lost out in the ini tial discovery to Piazzi [341], he redis covered the planet after Gauss [415] had calculated the orbit. He went on to dis cover the asteroid Pallas in 1802 and the asteroid Vesta in 1804. He was the first to suggest that the asteroids had origi nated through the explosion of a mod erately sized planet once moving in an orbit in the asteroid zone—a suggestion that is considered valid by many to this day. The 1002d asteroid to be discovered was named Olberfa in his honor. Olbers is best known nowadays for the “Olbers’s paradox.” He pointed out, in 1826, that if there were an infinite num ber of stars evenly distributed in space, the night sky should be uniformly light. He believed that the stars were infinite in number and that the reason the night sky was dark was that dust obscured most of the light. It is true that dust exists in in terstellar space, but its existence is not an adequate explanation of Olbers’s para dox. Astronomy had to await the discov ery of the expanding universe by Hubble [1136] for the realization that a “red shift" weakened the light of distant stars and kept the night sky dark—to say nothing of the fact that the universe is so large (and growing larger through ex pansion to such a degree) that the light pouring out of the stars has not, in any case, had time to fill it. [373] GADOLIN, Johan (gah'doh-leen) Finnish chemist Born: Abo, now Turku, June 5, 1760
Died: Wirmo, August 15, 1852 Gadolin’s father was himself an as tronomer and physicist (and bishop, too), so that the young man’s education began at home. Gadolin received his for mal training in Sweden (Finland was part of the Swedish realm in the eigh teenth century) and studied under Berg man [315]. He was a phlogistonist to begin with, but was converted to Lavoi sier’s [334] views. Gadolin’s textbook on chemistry, published in 1798, was the first in the Swedish language to teach the new chemistry. The great opportunity of a long and useful life as a professor of chemistry at Abo University came when on a trip to Sweden in 1794 he was shown a new mineral that had been obtained at the Ytterby quarry. It seemed to Gadolin as he tested the mineral that it contained a new “earth.” In those days, the word “earth” was ap plied to any oxide that was insoluble in water and resistant to the action of heat. Lime, magnesia, silica, and iron oxide were examples of very common earths. This new earth that Gadolin had located was clearly much less common than those others. It became known as a rare earth. In the next century the rare earth lo cated by Gadolin (and minerals similar to it) was found to contain over a dozen different elements, now called the rare earth elements. These amused three gen erations of chemists. In 1886, a genera tion after Gadolin’s death, one of the rare earth elements was named gadolin ium in his honor by Lecoq de Bois- baudran [736]. [374] HALL, Sir James Scottish geologist and chemist
1761
Died: Edinburgh, June 23, 1832 Hall, who succeeded to his father’s baronetcy in 1776, sat in Parliament from 1807 to 1812. He was an amateur geologist, attended lectures by Black [298] and, after making Hutton’s [297] acquaintance threw himself whole heartedly on the side of Hutton’s theories. He was also one of the first in England to adopt Lavoisier’s [334] new chemistry. Hutton supposed the chief agent of geological change to be the planet’s in ternal heat. Werner [355] and his fol 2 5 0
[375] TENNANT
PONS [376] lowers held out for the action of water. The neptunists, as Werner’s followers were called, pointed out that if rock had really been heated to high temperatures and had liquefied, it would cool into a glassy substance and would not become crystalline, whereas substances precipi tating from water solution make their appearance in crystalline form. This, they held, argued for water and against heat as the agent of change. Further more, said the neptunists, stones like limestone would decompose under strong heat; the vast deposits existing had never been heated, nor had the earth generally. It occurred to Hall that he might test these objections in the laboratory. At a glass factory he noticed that molten glass need not cool to ordinary glass. If it were cooled very slowly, it became opaque and crystalline. He therefore had rock melted in a furnace and showed that if it was allowed to cool quickly, it would form a glassy solid, but if allowed to cool slowly, it would form a crys talline solid. He further showed that if limestone was heated in a closed vessel, it would not decompose but would melt and then cool again to marble. Hall may be considered the founder of experimental geology and of geo chemistry. Although every one of his ex periments strongly backed Hutton’s views and demolished Werner’s, Hutton himself disapproved. Hutton believed that one could not study vast planetary changes by little experiments in furnaces. For that reason Hall did not publish his results until after Hutton’s death in 1797. Nevertheless the neptunists maintained their ascendancy until Lyell [502] pub lished a book supporting Hutton’s views at just about the time that Hall died. [375] TENNANT, Smithson English chemist
ber 30, 1761 Died: Boulogne, France, Febru ary 22, 1815 Tennant was the son of a clergyman and lost both parents as a youngster, his mother dying from an accident while horseback riding. For the most part he was self-educated through his teens and was interested in chemistry as a hobby. He had attended lectures given by Black [298] in 1781. During a trip to Sweden he met Scheele [329] and later was to make friends with another Swede, Berzelius [425]. He finally undertook medical studies, obtaining his doctor’s degree in 1796 from Cambridge, but he never practiced medicine. He maintained his interest in chemis try and in 1796 undertook, as Lavoisier [334] had done a quarter century before, the rather expensive experiment of burn ing a diamond. By measuring the carbon dioxide produced in the process, he was able to show that the diamond did not merely contain carbon but was all car bon. He did not complete the experiment himself, but went out horseback riding as was his daily custom. His assistant, however, was Wollaston [388], who was quite reliable. In 1803 he (as well as Wollaston) was working with platinum minerals. Ten nant discovered two metals something like platinum, yet with distinct properties and even less reactive. One he named iridium, from the Greek word for “rain bow” because of the different colors of its compounds. The other he named os mium, from the Greek word for “smell” because of the odor of one of its com pounds. Tennant also experimented with the fertilizing of soil with lime. In 1813 he was appointed professor of chemistry at Cambridge but did not teach long. In 1815, on a visit to France (just in time to witness the return of Napoleon from Elba), a small drawbridge gave under him and he and his horse were cat apulted into the ditch. Horseback riding finished him as it had his mother. [376] PONS, Jean Louis (pohns) French astronomer
France, December 24, 1761 Died: Florence, Italy, October 14, 1831
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