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441 [ 6 7 1 ] DONATI
ABEL [ 6 7 3 ] the universe as a whole than did Euclid’s geometry. [671] DONATI, Giovanni Battista (doh- nah'tee)
Italian astronomer Born: Pisa, December 16, 1826 Died: Florence, September 20, 1873
After obtaining his degree at the Uni versity of Pisa, Donati worked at the ob servatory in Florence, of which he be came the director in 1864. He is best known for his work on comets, discover ing six. One of them, discovered in 1858, was a brilliant and spectacular one and is still referred to as Donati’s comet. In 1864 he obtained the spectrum of a comet in the neighborhood of the sun. While yet at a distance from the sun a comet glowed only by reflected sunlight, as the spectrum clearly showed. Near the sun its own substance was heated to a glow and the spectrum changed radi cally. As a result, Donati was appointed a director of the Florence Observatory, with professorial rank. In 1868 Huggins [646] was able to identify the lines as those belonging to carbon-containing substances. This was the first step leading to the theories of comet structure, finally worked out nearly a century later by Whipple [1317], [672] LISTER, Joseph, Baron English surgeon Born: Upton, Essex, April 5, 1827
Died: Walmer, Kent, February 10, 1912
Lister was the son of J. J. Lister [445], who had invented an achromatic micro scope. He himself entered medicine, ob taining his degree from the University of London in 1852. As a surgeon he was interested in amputation and the new technique of anesthesia developed by Morton [617]. He was perturbed, however, by the fact that an amputation or other surgery might be painless and successful and yet the patient might die of the subsequent infection. In 1865 he learned of Pas teur’s [642] researches in diseases caused by microorganisms and it occurred to him to try to kill any germs in surgical wounds by chemical treatment. He used carbolic acid (phenol) for the purpose in 1867 and deaths by infection stopped. Eventually chemicals less irritating to tissue and even more effective in killing germs were discovered, but Lister and his carbolic acid had founded antiseptic surgery. Overriding initial resistance to his findings by medical conservatives, he succeeded in converting hospitals into something more than elaborate pauses on the way to the grave. In 1883 he was made a baronet and in 1897 he was raised to the peerage as Baron Lister of Lyme Regis. He was the first physician to sit in the House of Lords and in 1885 he succeeded Kelvin [652] as president of the Royal Society. [673] ABEL, Sir Frederick Augustus English chemist Born: Woolwich (now part of London), July 17, 1827 Died: London, September 6, 1902 After studying chemistry under Hof mann [604], Abel spent his entire career as a kind of military chemist, working with explosives. He pioneered the pro duction of smokeless powders with the invention, in 1889, of cordite, in collabo ration with Dewar [759], representing the climax. Cordite was a mixture of Sobrero’s [574] nitroglycerine and Schonbein’s [510] nitrocellulose to which some petro leum jelly was added. The mixture was comparatively safe to handle when purified ingredients were used. The re sulting gelatinous mass could be squirted out into cords (hence the name of the material) that, after careful drying, could be measured out in precise quanti ties.
For six centuries—since the time of Roger Bacon [99], once thought to be the inventor of gunpowder—battlefields had lain hidden under a progressively 4 4 2
[674] BERTHELOT BERTHELOT
thickening pall of gunpowder smoke, and artillery men had been blackened with it. It may be small comfort to have the scene of carnage relatively clear, but it is important militarily, for then gen erals can survey the battle’s progress in stead of losing it in man-made smoke. The Spanish-American War was the last important one fought with gunpowder (although fought seven years after the invention of cordite). Abel was knighted in 1891 for the in vention and created a baronet in 1893. [674] BERTHELOT, Pierre Eugène Marcelin (behr-tuh-loh') French chemist
Berthelot, the son of a physician, at tended the Collège de France, obtaining his doctor’s degree in 1854 after having studied under Dumas [514], Régnault [561], and Balard [529]. His doctoral thesis dealt with the synthesis of natural fats, which he formed by combining glyc erol with fatty acids, making a crucial step forward in the synthesis of organic compounds and advancing Chevreul’s [448] earlier work. Wohler [515] had synthesized urea, but only by rearranging the atoms in ammonium isocyanate; he had not deliberately combined atoms. Others, notably Kolbe [610], had done so, to be sure, but such syntheses were few and always yielded products that were well known in nature. Berthelot became professor of organic chemistry at the École Supérieur de Pharmacie in 1859 and moved on to the Collège de France in 1865. He went about the synthesis of organic com pounds systematically, and turned them out in hordes, including such well-known and important substances as methyl alco hol, ethyl alcohol, methane, benzene, and acetylene. The theory of a vital force that alone would suffice to form organic compounds had been damaged by Wohler and a few others. Berthelot ground it to bits. Berthelot was the first to synthesize or ganic substances that did not occur in nature, by combining glycerol with fatty acids that did not naturally occur in fats. He thus produced organic compounds that were part of no organism. From that moment on, it became increasingly difficult to talk of organic chemistry as the chemistry of the products of life; gradually, organic chemistry became lim ited to the chemistry of carbon com pounds, Kekule [680] being the first to advance such a definition formally. Later, when a term was needed for the chemistry of the products of life specifically, the word “biochemistry” (“life chemistry”) was introduced. In some ways Berthelot was conser vative. He was one of those who adopted atomic conventions only with reluctance. When Cannizzaro [668] established the matter of atoms and molecules to the satisfaction of most chemists, it was Berthelot who led (unavailingly) the op position. In the 1860s Berthelot was done with synthesis and turned to thermochemistry, the study of the heat of chemical reac tions. In some of his work he had un knowingly been anticipated by Hess [528], but he went much further. He devised a calorimeter within which he could mea sure the heat of chemical reactions and ran hundreds of determinations. This work along with that being conducted by H.PJ.J. Thomsen [665] threw the sci ence of thermochemistry into high gear. He invented the terms “exothermic” and “endothermic” for reactions that, respec tively, gave off heat and took it up. Berthelot suggested that the heat evolved by a chemical reaction was its driving force. If he had been right, there would be no such thing as a reversible reaction. Williamson [650] had shown that such reactions, capable of moving in either direction, did exist. It required the more subtle concept of free energy and chemical potential, evolved by Gibbs [740], to settle the matter of the driving force behind chemical reactions. During the disastrous Franco-Prussian War, Berthelot was in charge of the scientific defense of Paris. After the es tablishment of the Third French Repub lic in 1871, he took an active part in public affairs. In 1881 he became a sena- 4 4 3
[ 6 7 5 ] COHN
SWAN [ 6 7 7 ] tor, and in 1886 he entered the cabinet. In 1895 he even served a year as foreign secretary. Nor did he lag behind in scientific administration, for in 1889 he succeeded Pasteur [642] as permanent secretary of the French Academy of Sci ences. [675] COHN, Ferdinand Julius German botanist Born: Breslau, Silesia (now Wroclaw, Poland), January 24, 1828
Cohn, the son of a Jewish merchant, was a child prodigy, beginning to read when he was two years old. He was educated at the universities of Breslau and Berlin, obtaining his doctorate from the latter in 1847, since the former would not grant the doctorate to a Jew. He sided with the liberals during the revolutionary year of 1848, which, com bined with his religion, hampered his subsequent advancement, even though he had studied under J. P. Muller [522] and had done particularly well. He finally obtained a grudging professorial appointment in botany at Breslau in 1857. He was early interested in algae (that is, one-celled plant life). He had already shown in 1850 that the protoplasm of plant and animal cells were essentially identical and that there was therefore only one physical basis of life. As the 1860s progressed he became in creasingly interested in bacteria, thanks in part to Pasteur’s [642] work, and was the first to treat bacteriology as a special branch of knowledge. In 1872 he pub lished a three-volume treatise on bacte ria, which may be said to have founded the science. He made the first systematic attempt to classify the bacteria into gen era and species. He was also the first to describe bacterial spores and their resis tance to even boiling temperatures. It was Cohn who discovered and en couraged Koch [767] and saw to the publication of the latter’s paper on anthrax. Cohn was a successful teacher and an effective popularizer of science. [676] BUTLEROV, Alexander Mikhai lovich (boot'lyuh-ruf) Russian chemist
the Tatar Republic of the Soviet Union), September 6, 1828
August 17, 1886 Butlerov, the scion of a family of landed gentry, entered the University of Kazan in 1844, and only gradually grew interested in chemistry, obtaining his doctorate in 1854 from the University of Moscow. In that same year he accepted a professorial post at Kazan. In the late 1850s Butlerov traveled through western Europe and met both Kekule [680] and Couper [686]. He was an eager convert to the new structural theory and in a series of publi cations in the 1860s he worked out its consequences, particularly in connection with a phenomenon called “tau- tomerism” in which a compound can possess two structures by the shift of a hydrogen atom. Butlerov went even further than Kekule and was the first to speak of the chemical structure of a compound. In later life, like Hare [428] before him and Lodge [820] after him, Butlerov became interested in spiritualism. Among the group of scientists that was organized to investigate his suggestions was Mende leev [705], No evidence for the truth of spiritualism was found and Mendeleev was outspokenly critical of the whole matter though he remained friends with Butlerov. [677] SWAN, Sir Joseph Wilson English physicist and chemist
October 31, 1828 Died: Warlingham, Surrey, May 27, 1914 Swan spent his youth as a druggist’s apprentice but graduated from that to chemistry. In Newcastle he was em ployed by a firm that manufactured pho tographic plates. At that time the solu tion had to be smeared on the plates in liquid form, a process both touchy and
[677], SWAN
STEWART [678] messy. Swan, however, showed that heat merely increased the sensitivity of the so lution so that the plate could be dried with actual benefit rather than harm. By 1871 he had originated the dry plate method of photography, which greatly simplified the process and led the way to Eastman’s [852] further developments fifteen years later. But even before then, Swan had be come involved in the real interest of his life, that of producing light by elec tricity. Some inventors had tried to pro duce light by heating a platinum wire to incandescence but such wires didn’t last long. Swan realized that carbon would withstand heat better than platinum but carbon would quickly bum, when heated, unless it was enclosed in a vac uum. In 1848 he began to use thin strips of carbonized paper within an evacuated bulb. By 1860, twenty years in advance of Edison [788], Swan had an electric light with a carbon filament. Unfortu nately he could not obtain a vacuum good enough to keep it working a sufficient length of time. By the late 1870s, when the tech niques for producing vacuums had im proved to the necessary degree, Edison was already at work and the two finally produced the practical incandescent bulb at approximately the same time. Edison was the more active (as always) in ob taining patents. In addition, he devised a host of subsidiary equipment designed to produce the electricity necessary to keep banks of incandescent lights burning at constant levels despite rapid fluctuations in the extent of their use. Edison there fore rightly receives the lion’s share of the credit. Swan lamps quickly gained popularity in Great Britain. In 1881 the House of Commons was lit by them; in 1882 the British Museum was. Swan’s own house was the first private house in Great Brit ain to be lit by electricity, but Kelvin [652] followed suit by 1884. Edison and Swan settled differences out of court and formed a joint company in Great Britain in 1883, and electrical lighting assumed absolute dominance in the field of illumi nation by the century’s end in the indus trialized regions of the world. Swan continued to try to improve the filaments, devising a plan whereby ni trocellulose could be extruded through holes to form thin threads. The idea was to carbonize them for use in electric light bulbs. That came to nothing, but Swan patented the process in 1883 and this paved the way for Chardonnet [743] and the development of artificial fibers. Swan was knighted in 1904. [678] STEWART, Balfour Scottish physicist
1828
Died: near Drogheda, Ireland, December 19, 1887 After an education at the universities of Dundee and of Edinburgh, Stewart, the son of a merchant, joined the staff of the Kew Observatory. He became direc tor in 1859 and in 1870 joined the fac ulty of Owens College in Manchester. He interested himself in the theory of heat exchange first enunciated by Prévost [356], extending and generaliz ing it. He recognized that at constant temperature, radiation and absorption of energy equal each other at all wave lengths; and he was aware of the proper ties of the “black body” enunciated inde pendently by the more famous Kirchhoff [648], He collaborated in astronomical research with De la Rue [589] and was also interested in the earth’s magnetic field. It was in this last connection that he is now best known. In 1882 he suggested, on the basis of a theory of Gauss [415], that the daily variations in the orientation of earth’s magnetic field might be accounted for by horizontal electric currents in the upper atmosphere. This seemed an outrageous suggestion at the time, but a generation later the work of Kennelly [916] and Heaviside [806] established the validity of the notion in more sophisticated form and revealed the existence of the iono sphere, where electric charges did indeed permeate the thin wisps of upper air. Stewart was one of those nineteenth- century scientists who saw no conflict in science and religion and who strove to show this in his popular writings.
[679] POGSON
KEKULÉ VON STRADONITZ [680] [679] POGSON, Norman Robert English astronomer
1829
Died: June 1891 Pogson worked at observatories in En gland and in India and discovered nine asteroids in the 1850s and 1860s. His most fruitful contribution was in connection with Hipparchus’ [50] notion of dividing the stars into six magnitudes based on brightness. In 1850 Pogson pointed out that the average first-magni tude star was just about a hundred times as bright as the average sixth-magnitude star. He suggested that this hundredfold difference be defined as representing an exact five-magnitude difference. This meant that a one-magnitude difference represented a ratio equal to x/100, or 2.512. This suggestion was adopted and increasingly accurate methods of measuring stellar brightness have made it possible to assign magni tude values to the nearest tenth or, some times, hundredth, and to assign magni tude values to the planets, the moon and the sun. Thus, Barnard’s Star has a magnitude of 9.5, Sirius one of —1.58, and the sun —26.91. [680] KEKULfi VON STRADONITZ, Friedrich August (kayToo-lay) German chemist
tember 7, 1829 Died: Bonn, Prussia, July 13, 1896
Kekule, who was of Czech descent, in tended to be an architect but fell under the spell of Liebig [532] and found him self a chemist. He traveled through En gland and France (meeting Williamson [650] in England and studying under Dumas [514] in France). When he re turned to Germany he lectured (in only mediocre fashion) at Heidelberg and set up a private laboratory for his own work. In 1856 he obtained a profes sorship at Heidelberg. By that time he was interested in the notions of valence, toward which Can nizzaro [668] and Kekule’s friend Wil liamson had been groping, and which Frankland [655] was finally to put into clear-cut form. Until the 1850s, chemists had been denoting the atomic composi tion of molecules by simply listing the numbers of each element in a fixed order. Using symbols for the elements, sodium chloride is NaCl, water is H20, ammonia NH3, methane CH4, ethyl al cohol C2HeO, diethyl ether C4H10O, ace tic acid C2H40 2, and so on. There was little thought of arranging all the various atoms in any particular fashion. Once Frankland had advanced the the sis that the atom of a particular element might combine with a fixed number of other elements, however, Kekulé got the notion that these fixed combinations might be represented in chemical for mulas as specific patterns of atoms making up a molecule. In 1858, the same year he took up a professorship at the University of Gent in Belgium, through the kindly offices of Stas [579], he presented his theory. His particular contribution was in respect to carbon. It was tetravalent, he suggested; that is, one carbon atom can combine with four others. Moreover he main tained that one, two, or three of the four bonds of a carbon atom could be at tached to another carbon atom so that chains of such atoms could be formed. Pretty soon the notion of connecting atoms by little dashes was introduced by Couper [686] and Kekulé structures began to sweep the world of chemistry, although Kolbe [610], for one, poured withering scorn upon the whole notion. Allowing hydrogen one bond, oxygen and sulfur two each, nitrogen three, and carbon four, it meant that: water became H —O—H, ammonia
H - N - H , H methane H—C —H, H
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