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436 [ 6 6 2 ] CHARCOT
HOPPE-SEYLER [ 6 6 3 ] He then underwent a second kind of conversion when he studied under Kekule [680], adopting the latter’s struc tural theory of organic compounds. In his own chemical career, Erlen- meyer was the first to synthesize a num ber of compounds of organic chemical interest. He synthesized the important amino acid, tyrosine, and the compound guanidine, working out the correct struc tural formula for the latter, and for the related compounds creatine and creat inine. In adopting Kekule’s theories, Erlen- meyer used straight lines for bonds, two lines for double bonds and three lines for triple bonds. His constant use of these conventions went far to popularize them throughout chemical writings—and they are still used to this day, although more accurate conventions have been worked out in line with the quantum mechanical modifications of Pauling [1236]. Erlenmeyer also quickly adopted Kekule’s benzene structure and showed that the structural formula of naphtha lene was a double benzene ring holding one side of the hexagon in common. To the chemical student, Erlenmeyer is best known for the conical flat bot tomed vessel he invented that is known universally as an Erlenmeyer flask. [662] CHARCOT, Jean Martin (shahr- koh')
French physician Born: Paris, November 29, 1825 Died: Lake Settons, Nievre, Au gust 16, 1893 Charcot, the son of a wheelwright, re ceived his M.D. in 1853 from the Uni versity of Paris. In 1860 he became a professor at the university, and begin ning in 1862 he established a major neu rological department at La Salpêtrière Hospital. He made extensive investi gations into illnesses involving nerve de generation, and was one of the great clinicians of his time. In 1872 he began to work on hysteria and as part of the therapy he began to use the techniques of hypnosis that Braid [494] had introduced to medicine. It was in this connection that Charcot made his greatest single mark in the history of medicine; for in 1885 one of his stu dents was Freud [865] who, through Charcot’s work, became interested in the treatment of hysteria and in the uses of hypnotism, and then went far beyond that.
[663] HOPPE-SEYLER, Ernst Felix Immanuel (hope'uh-zy'ler) German biochemist
December 26, 1825 Died: Lake Constance, Bavaria, August 10, 1895 Hoppe-Seyler began life as Ernst Hoppe, the son of a minister. Orphaned at an early age, he was brought up by his brother-in-law, a Dr. Seyler, whose name he adopted as part of his own. Hoppe-Seyler began as a physiologist, gaining his medical degree at Leipzig in 1851. He served as assistant to Virchow [632] at the University of Berlin in 1856. He prepared hemoglobin in crystalline form in 1862, and his interest shifted to chemistry. His first professorial appoint ment in 1864 was in applied chemistry. In 1872 he successfully combined the two sciences and was appointed profes sor of physiological chemistry (now bet ter known as biochemistry) at the Uni versity of Strasbourg. He established the first laboratory to be devoted exclusively to biochemistry and in 1877 followed that with the first scientific journal to be devoted entirely to that study. In 1871 he had discovered invertase, an enzyme that hastens the conversion of table sugar (sucrose)- into two simpler sugars, glucose and fructose. He also dis covered lecithin, a fatlike substance con taining nitrogen and phosphorus. Leci thin is a representative of what are now termed phospholipids, compounds of fundamental importance to life, since no living cell is without them—and yet their function in cells is even yet uncer tain.
In 1875 Hoppe-Seyler suggested a sys tem of classifying proteins which is still in use today. Most important of all, his student Miescher [770] discovered the 4 3 7
[664] STONEY
GRAMME [666] nucleic acids and Hoppe-Seyler began research upon them. Further work in that direction was done by Hoppe- Seyler’s onetime assistant, Kossel [842]. [664] STONEY, George Johnstone Irish physicist
County (now County Offaly), February 15, 1826
Stoney was educated at Trinity College in Dublin, paying his way through by coaching the athletic teams. In 1848 he worked as an assistant to Rosse [513], and in 1852 was appointed professor of natural philosophy at Queen’s College in Galway. He worked busily in physical research, yet in the end his prime fame rested on his introduction into the scientific vocabulary of a single word. From the days that Faraday [474] had elaborated his laws of electrochemistry, it seemed that the logical way of explain ing their existence might be to suppose that electricity was not a continuous fluid but consisted of particles of fixed minimum charge. Arrhenius’ [894] ionic theory made this seem even more proba ble, and in 1891 Stoney suggested that this minimum electric charge be called an electron. When, later that decade, J. J. Thom son [869] finally proved Crookes’s [695] contention that the cathode rays were streams of particles and found that each particle carried what was probably Stoney’s minimum quantity of negative electric charge, the name was applied to the particle rather than to the quantity of charge. [665] THOMSEN, Hans Peter Jørgen Julius Danish chemist Born: Copenhagen, February 16, 1826
Died: Copenhagen, February 13, 1909
Thomsen, the son of a bank auditor, obtained his master’s degree at the Uni versity of Copenhagen in 1843 and slowly worked his way up the faculty ladder till he became professor of chem istry in 1866. He was also a member of the Copenhagen Municipal Council for thirty-five years and it was his driving civic force that was responsible for the development of Copenhagen’s gas, water, and sewage system. His work on thermochemistry paral leled that of Berthelot [674], and he made about thirty-five hundred calori metric measurements. Like Berthelot, he wrongly considered the heat evolution of a reaction to be its driving force. He was also the first to measure the relative strengths of different acids, and pre dicted the existence of a group of inert or “noble” gases (something verified a half century later by Ramsay [832]). Thomsen shone in applied chemistry. In 1853 he worked out a method of manufacturing sodium carbonate from a mineral called cryolite, which is found only in the Danish island Greenland, and made himself rich. (At the time, cryolite had no other use, but a generation later Hall [933] was to turn it to the still more important task of manufacturing cheap aluminum.) [666] GRAMME, Zénobe Théophile (gram)
Belgian-French inventor Born: Jehay-Bedegnée, Belgium, April 4, 1826 Died: Bois-Colombes, Hauts-de- Seine, France, January 20, 1901 Gramme was the son of a Belgian gov ernment clerk and did not do well at school. To the end of his life, in fact, he remained essentially uneducated. Never theless, he was skillful with his hands, and an ingenious tinkerer with electrical equipment. In 1856 he went to Paris and re mained near it the rest of his life. He took a job with a firm specializing in the manufacture of electrical equipment. In 1867 he built an improved dynamo for the production of alternating current, and in 1869 a dynamo for producing di rect current. Faraday [474] and Henry [503] had established the principles that made such
[6 6 7] CARRINGTON CANNIZZARO [668] dynamos possible but their own versions were laboratory devices. It was Gramme who built the first electrical generating equipment that was truly useful in indus try. It was upon Gramme’s devices that the electrical industry was built. [667] CARRINGTON, Richard Christo pher English astronomer Born: London, May 26, 1826 Died: Churt, Surrey, November 27, 1875 Carrington, like Joule [613] was the son of a wealthy brewer. He was pri vately educated and the original inten tion was to prepare him for the ministry. It was with that purpose in mind that he entered Cambridge in 1844. However, he attended lectures on astronomy and was fascinated enough to make that his life- work. He established a private observatory in 1852 and observed both day and night. At night he plotted the positions of the stars in the area circling the north celes tial pole. In the day he observed the sun. Between 1853 and 1861 he observed the sun and its spots almost as as siduously as Schwabe [466] had done two decades earlier. Where Schwabe had merely counted the spots, however, Car rington plotted their position on the sun. In order to do it he had to allow for the rotation of the sun, and he measured that too, by following the spots, as Gali leo [166] had done two and a half cen turies earlier, but in more detail. He found that the sun did not rotate all in one piece, or at least that the spots did not circle the sun all at one angular rate. Instead a point on its equator ro tated in just about twenty-five days while a point at the solar latitude 45° took twenty-seven and a half days to complete a rotation. The sunspots were therefore not fixed to any solid solar body. In 1859 he observed a starlike point of light burst out of the sun’s surface, last five minutes, and subside. This is the first recorded observation of a solar flare. Carrington speculated that a large me teor had fallen into the sun. It was not until Hale [974] invented the spec- trohelioscope nearly three quarters of a century later that these flares, which proved to be part of the sun’s own tur bulence, could be properly studied. In 1858 Carrington inherited the brew ery on his father’s death. He sold it in 1865, however, in order that he might continue to devote himself entirely to as tronomy, but he died of a stroke before he was fifty.
need-dzah'roh) Italian chemist
1826
Died: Rome, May 10, 1910 Cannizzaro, the tenth and youngest child of a magistrate, early attracted the favorable attention of Melloni [504]. As for Cannizzaro himself, he was a fiery person who attracted controversy and did not fear a strong line of action. In his early life this led Cannizzaro into political turmoil, which might have brought him to the end of the road too quickly. In 1848 a series of revolutions shook Europe and one of them affected the inefficient and corrupt government of the Kingdom of Naples, of which Sicily was then a part. Cannizzaro was one of the revolutionaries, but since the revolu tion failed (as most of them did that year), he had to leave for France in a hurry. He worked in France under Chevreul [448] while waiting until it was safe to return home. In 1851 he returned to Italy, but not to Naples. Instead, he worked in Sardinia in northwestern Italy, the only truly free portion of the penin sula at that time. In 1853 he discovered a method of converting a type of organic compound called an aldehyde into a mixture of an organic acid and an alcohol. This is still called the Cannizzaro reaction. But greater things lay ahead. During the 1850s chemistry was being brought to a distressing pitch of confu sion. The atomic theory of Dalton [389] was widely accepted by then, but methods for writing formulas to indicate the structures of substances in terms of 439 [668] CANNIZZARO GEGENBAUR
molecules and of the atoms making up the molecules was a matter of strong controversy. The trouble was that there was no general agreement on the atomic weights of the different elements, and without such agreement there could be none on the elementary makeup of different compounds. Berzelius [425] had prepared an excellent table of atomic weights and Stas [579] was in the pro cess of preparing a still better one, but there was no agreement on just how these were to be used, as opposed to the more easily measured but less funda mental “equivalent weights.” The net result was that a simple com pound like acetic acid (CH3COOH) was given nineteen different formulas by var ious groups of chemists. Finally Kekule [680] in desperation suggested a conference of important chemists from all over Europe to discuss the matter, and an international scientific meeting was held for the first time in his tory. It was called the First International Chemical Congress and met in 1860 in the town of Karlsruhe in the little king dom of Baden, just across the Rhine from France. Among the 140 delegates attending the conference aside from Kekule were Wohler [515], Liebig [532], Dumas [514], Bunsen [565], Kopp [601], Kolbe [610], Frankland [655], Mende leev [705], Beilstein [732], Baeyer [718], and Friedel [693]. Cannizzaro attended too, bursting with a missionary zeal. In 1858 he had come across Avogadro’s [412] hypothesis, which had lain disregarded for about half a century. (Avogadro himself had died two years earlier.) He saw that the hypothesis could be used to determine the molecular weight of various gases. From the molecular weight, the consti tution of the gases could be determined. From that and the law of combining vol umes of Gay-Lussac [420] the atomic weights as determined by Berzelius could be fully justified and clarified. Canniz zaro published a paper on the subject and went to the congress to do more. He made a strong speech, introducing Avogadro’s hypothesis, describing how to use it and explaining the necessity of dis tinguishing carefully between atoms and molecules. He also distributed copies of a pamphlet in which he explained his points in full. By the end of the congress he had ac tually convinced some of the chemists. After the congress further discussions convinced more. Atomic weights came into their own and chemists moved steadily into total agreement about the chemical formulas of almost all the simpler compounds. Kekule himself advanced his method of representing these formulas, which greatly clarified matters. Chemistry in general was feeling the impact of height ened precision of measurement—witness the work of Regnault [561]—and many cobwebs were soon to be cleared away. In particular, Cannizzaro impressed both Mendeleev and Lothar Meyer [685], helping start them on the road to the periodic table. The year 1860 saw a turning point in Cannizzaro’s personal life. The small states of the Italian peninsula were being unified, partly by a movement from within Sardinia and partly with the half hearted help of Napoleon III of France. Cannizzaro joined the small army of Giuseppe Garibaldi in its attack on Naples. Naples fell at once and merged with the rest of the peninsula to form the new kingdom of a united Italy. He received a professorship at Palermo in 1861, and at Rome in 1871 after that city was finally united to the kingdom. Later in life Cannizzaro entered Italian politics once more, under less turbulent conditions, and finally became vice president of the Italian senate. As the importance of his service at the Congress of Karlsruhe became apparent in the brilliant light of hindsight, he received the Copley medal of the Royal Society in 1891. [669] GEGENBAUR, Karl (gay'gen- bowr) German anatomist Born: Wurzburg, Bavaria, August 21, 1826 Died: Heidelberg, June 14, 1903 4 4 0
[670] RIE MANN
RIEMANN [670] Gegenbaur studied at the University of Wurzburg under men such as Kolliker [600] and Virchow [632]. He obtained his medical degree in 1851 and after some years in Italy joined the faculty of the University of Jena in 1855. In 1873 he transferred to the University of Hei delberg, remaining there until his retire ment in 1901. He specialized in comparative anat omy, particularly as reflected in the em bryos. He showed how embryonic struc tures that in fish eventually come to form gills form other organs, from Eu stachian tubes to the thymus gland, in land vertebrates. This point of view was clearly pro-evolution, something Gegen baur himself stressed, and led to the more radical views of Gegenbaur’s pupil Haeckel [707]. Gegenbaur extended the views of his own teacher, Kolliker, to show that not only mammalian eggs and sperm but all eggs and sperm, even the giant eggs of birds and reptiles, were sin gle cells. [670] RIEMANN, Georg Friedrich Bernhard (ree'mahn) German mathematician
tember 17, 1826 Died: Selasca, Italy, July 20, 1866
Riemann was the son of a Lutheran pastor and his original ambition was to follow in his father’s footsteps. He stud ied Hebrew and tried to prove the truth of the Book of Genesis by mathematical reasoning. He failed, but his talent for mathematics was discovered and his am bitions shifted. He entered the University of Got tingen in 1846, but his college career was interrupted by the Revolution of 1848, during which he served with the Prussian king, Frederick William IV, against the revolutionaries (though he opposed his own king, Ernst August of Hannover). With the danger past and the king victo rious, Riemann returned to his studies. In 1851 his doctor’s thesis at Got tingen received the approval of none other than the aged Gauss [415]. In his short life (he died of tubercu losis before he turned forty) Riemann contributed busily to many branches of mathematics. His most famous contri bution was a non-Euclidean geometry different from those of Lobachevski [484] and Bolyai [530], This he ad vanced in 1854. Riemann’s geometry used in place of Euclid’s [40] axiom on parallels the statement that through a given point not on a given line no line parallel to the given line could be drawn. He conse quently also had to drop the Euclidean axiom that through two different points, one and only one straight line could be drawn. In Riemann’s geometry, any number of straight lines could be drawn through two points. Furthermore, in Rie mann’s geometry there was no such thing as a straight line of infinite length. One consequence of Riemann’s axioms was that the sum of the angles of a trian gle in his geometry was always more than 180°. Actually, although this sounds odd to anyone used to Euclid’s geometry, it is perfectly reasonable. Riemannian geome try is followed if we consider the surface of a sphere and restrict our figures to that surface. If we define a straight line as the shortest distance between two points, that would be the segment of a great circle on a spherical surface. On the earth’s surface, the great circles are never infinite in length; through two points any number of great circles may be drawn; there are no parallel lines since all great circles intersect at two points; a triangle constructed of great circles has angles that add up to more than 180°. Riemann generalized geometry to the point where he considered geometry in any number of dimensions and situations in which measurements changed from point to point in space but in such a way that one could transform one set of mea surements into another according to a fixed rule. At the time, this sounded like a wonderful exercise in pure mathe matics but one that was divorced from reality. A half century later Einstein [1064] was able to show that Riemann’s geometry represented a truer picture of
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