Biographical encyclopedia
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601 [938] CORRENS
HARTMANN [940] ance of God and a liberator to men of the white race as well as the black.” In 1953, ten years after his death, the plan tation on which he was born was made a national monument. Perhaps his greatest contribution was the clear demonstration provided by his life story of the fact that it is tremen dously worth while to educate human beings of any race. [938] CORRENS, Karl Franz Joseph Erich (kawr'ens) German botanist Born: Munich, September 19, 1864
Died: Berlin, February 14, 1933 Correns, the son of an artist, married a niece of Nageli [598] under whom he had studied. Like De Vries [792], he was engaged in a line of research which by 1900 had led him to the independent elucidation of the laws of genetics, then discovered Mendel’s [638] earlier work and published his own merely as confirmation. By the fact of having been anticipated, Correns lost his chance at fame. He served the last two decades of his life, however, as director of the Kaiser Wil helm Institute for Biology in Berlin, so he did not go entirely without recogni tion. Correns was honest enough, further more, to publish the correspondence be tween Mendel and Nageli, which re vealed the shortsightedness of his uncle- in-law. Correns’ own unpublished manu scripts were preserved at his institute until they and it were destroyed in the bombing of Berlin in 1945. [939] IVANOVSKY, Dmitri Iosifovich (ee-van-uf'skee) Russian botanist Born: Gdov, November 9, 1864 Died: USSR, June 20, 1920 Ivanovsky, the son of a landowner, studied at the University of St. Peters burg, where Mendeleev [705] was one of his teachers, and graduated in 1888. From the start he was interested in to bacco mosaic disease, an infection that damaged the valuable tobacco crop, and the most obvious symptom of which was the mosaic pattern that formed on the leaves of the affected plants. In 1892 he mashed up infected leaves and forced them through a very fine filter designed to remove all bacteria. He found that the liquid that passed through the filter could still infect healthy plants. He thus had the proof in hand that there was a pathogenic agent smaller than bac teria—an agent that was later to be named a “virus.” However, Ivanovsky suspected that there was something wrong with his filters and did not draw the necessary conclusion, leaving it to Beijerinck [817] a few years later to repeat the experiment, accept the conclu sion, and receive the credit for the dis covery of viruses. [940] HARTMANN, Johannes Franz German astronomer
1865
Died: Gottingen, September 13, 1936
Hartmann, the son of a merchant, ob tained his Ph.D. at the University of Leipzig in 1891. In 1896 he moved on to the observatory at Potsdam, and there he did the work for which he is best known. In 1904 he studied the spectrum of delta-Orionis and found that although there was a radial shift involving most of its lines, there were calcium lines in their accustomed place, indicating that the calcium at least was stationary with re spect to Earth. Since it was unlikely that the entire star was moving and leaving its calcium behind, Hartmann came to the conclusion that there was interstellar matter in the form of dust or gas that in cluded calcium, and that over the vast distances between the star and Earth this gas and dust absorbed enough light to produce detectable dark lines. This was the first indication of the existence of in terstellar matter. 602 [941] PASCHEN
ZSIGMONDY [943] [941] PASCHEN, Louis Carl Heinrich Friedrich (pahsh'en) German physicist Born: Schwerin, Mecklenburg, January 22, 1865 Died: Potsdam, February 25, 1947 Paschen was bom into a family of mil itary tradition, but he chose an academic life. He studied at the University of Strasbourg under Kundt [744] and re ceived his Ph.D. in 1888, then went on to serve as Hittorf’s [649] last assistant. He joined the faculty of the Physical In stitute of the Technische Hochschule at Hannover in 1893. Paschen’s chief field of interest was spectroscopy, and in 1895 he carefully studied the spectrum of helium, newly discovered by Ramsay [832], and showed that it was indeed identical with the solar helium discovered by Janssen [647] and Lockyer [719]. In 1908 he discovered a new Paschen series of lines in the hydro gen spectrum. Paschen was probably the most skillful experimental spectroscopist of his time and he carefully produced the results that bore out the theories of Zeeman [945] and Sommerfeld [976], He was not a German nationalist, however, and had stuck to his research during World War I, for instance, mak ing no effort to involve himself in war work. Once the Nazis, under Hitler, came to power in 1933, this made it pos sible for the super-Nazi Stark [1024] to oust Paschen from the presidency of a scientific association and take it over himself. Paschen, forced into retirement, survived World War II and, though he lost his home and possessions in a bomb ing raid in 1943, lived to see the destruc tion of the Nazi regime. [942] WEISS, Pierre (wise) French physicist Born: Mulhouse, Haut-Rhin, March 25, 1865 Died: Lyon, October 24, 1940 Weiss, the son of a haberdasher, was bom in the province of Alsace, which was annexed by Germany following the Franco-Prussian War. The family re mained in Alsace and Weiss was edu cated in German and Swiss schools but, at the age of twenty-one, decided he wanted to be a Frenchman. After gradu ating at the top of his class from the Zürich Polytechnikum in 1887, he went to Paris for further education. His interest was chiefly in magnetism, and in 1907 he worked out an explana tion for ferromagnetism. All atoms are made up of charged particles and mag netic properties always accompany elec tric charge. However, only iron and a few related metals show strong fer romagnetic properties (from ferrum, the Latin word for “iron”) as opposed to weak paramagnetic properties. Weiss ad vanced the notion of unusually strong coupling of individual atomic magnets which caused them all to point in the same direction, forming “domains” of cumulative magnetic intensity. Iron con sists of these domains, which can point in various directions, but if forced by some external magnetic field to line up in a single direction the metal becomes an overall magnet. In 1919, when Alsace was returned to France, Weiss established a physics insti tute at Strasbourg that became a leading center of magnetic research. He retired in 1936 but lived long enough to see German troops in Alsace again in World War II. He fled to Lyon and died there not long after the French surrender brought the nation to its humiliating nadir.
[943] ZSIGMONDY, Richard Adolf (zhig/mun-dee) Austro-German chemist
1865
Died: Gottingen, Germany, Sep tember 23, 1929 Zsigmondy, the son of a dentist, earned his Ph.D. in organic chemistry at the University of Munich in 1890. In his postdoctorate years, however, when he worked with Kundt [744], he grew inter ested in the colors produced by organic 603 [943] ZSIGMONDY STEINMETZ
solutions of gold, when these were ap plied to porcelain. This roused his inter est in colloid chemistry, a science Gra ham [547] had founded a generation be fore.
From 1897 to 1900 he was employed at the Jena glassworks, where he was particularly interested in colloidal gold (gold that was broken up into such fine particles by one means or another that it did not settle out but remained in sus pension in water or other solvent, form ing deeply colored red or purple liq uids). He also produced several types of colored glasses, including a white vari ety called milk glass that became very popular.
It is the frustration of the colloid chemist that the particles making up the colloid are too small to be seen in an or dinary microscope. Improvements in de sign are useless because the limitation lies in the nature of light itself. Objects smaller than the wavelengths of visible light (and this includes the colloidal par ticles) cannot be made out no matter how perfect the microscope lenses are. However, colloidal particles are large enough to show the Tyndall [626] effect, that is, to scatter light. It occurred to Zsigmondy that this could be taken ad vantage of. If light was shone through a colloidal solution and if a microscope was adjusted at right angles to the beam of light, then only the scattered light would enter the microscope. Even if the colloidal particles could not be seen in detail, they could at least be made out as points of light that could be counted, and the movements of which could be studied. From this the size of the indi vidual particles and even something about their shape could be deduced. At the time, most chemists disagreed with Zsigmondy’s theory about colloid structure. He was sure an ultramicro scope would prove his point. In 1900, therefore, he quit the glassworks and joined with a physicist to produce such a device. By 1902 the instrument was de veloped. Zsigmondy used it on colloidal gold preparations and at once it was quite clear that his theories were wrong. He had succeeded in neatly proving the theories of his opponents. In 1908 he received a professorial ap pointment at the University of Gottingen and there built up an excellent center for colloidal research. In 1925, in recogni tion for his work on colloids, he was awarded the Nobel Prize in chemistry. Zsigmondy’s ultramicroscope is still of great importance in colloid studies, but in most fields of research where great magnification is required, it has been outdistanced by the electron microscope devised by Zworykin [1134] a generation later. [944] STEINMETZ, Charles Proteus (originally Karl August) German-American electrical engi neer
Wroclaw, Poland), April 9, 1865 Died: Schenectady, New York, October 26, 1923 A hunchback from birth (a congenital defect from which Steinmetz’s father and grandfather also suffered), Steinmetz led a lonely, solitary life, lit only by the flame of his genius and the gentleness of his soul. This loneliness was, in part, de liberate, for he never considered mar riage, the reason being his reluctance to pass on his deformity to another genera tion.
Yet if he could have passed his men tality on as well, it might have been worth it to the world if not to his chil dren. Already in high school his work was such that his proud father, a book binder by trade, bound his papers. He might have gone on to a scientific career that would have reflected glory on his nation, but in his youth he was openly a socialist and in conflict, therefore, with the authorities. The fact of his Jewish or igin did not make matters easier for him either. He was placed under police sur veillance in 1887 and in 1889, shortly before he was to obtain his Ph.D., he fled first to Switzerland and then to the United States; it was Germany’s loss and America’s gain. When he took out his American citi zenship papers he changed his German 6 0 4
[944] STEINMETZ NAGAOKA
first name Karl to the American Charles, adding the middle name Proteus (a Greek demigod with an infinitely changeable body) to indicate the change in name and nationality. In 1893 the small factory for which he worked was absorbed by the General Electric Company in Schenectady, where he remained for the rest of his life, uni versally recognized as one of America’s foremost electrical geniuses. His eccen tricities became famous. “No smoking, no Steinmetz,” he growled, when gently informed that smoking was absolutely forbidden on the laboratory grounds. He stayed—and smoked—but smoking re mained absolutely forbidden for every one else. He loved to work on intricate prob lems while drifting lazily in a canoe. His softheartedness was also famous. He sat shivering through the winter once rather than disturb a family of mice in the heating equipment. His greatest achievement was to work out (while still in his twenties) in com plete mathematical detail the intricacies of alternating current circuitry, using complex numbers (involving the famous square root of minus one), thus making use of Wallis’s [198] two-century-old concept. It was this that made it possible to design alternating current (a.c.) equipment most efficiently. His text books slowly spread his theories among the electrical engineering profession and completed the victory of a.c. over direct current (d.c.) that had been begun by Tesla [867], In addition to this towering work of theory, he is credited with over two hundred patents for inventions in every phase of electrical engineering. He remained a socialist and toward the end of his life ran (unsuccessfully) for state office on the Socialist ticket. He also carried his socialist principles to the almost-unheard-of extreme of refusing more than a modest salary. The importance of his theoretical work was beyond the grasp of anyone but spe cialists. However, he also built genera tors capable of producing electricity at extremely high potential. The study of discharges so produced was of consid erable importance and it was this “man made lightning” that made Steinmetz’s name most impressive to the layman. [945] ZEEMAN, Pieter (zay'mahn) Dutch physicist Born: Zonnemaire, Zeeland, May 25, 1865 Died: Amsterdam, October 9, 1943
At Leiden University, Zeeman, the son of a Lutheran minister, studied under Kamerlingh Onnes [843] and Lorentz [839]. He gained his Ph.D. in 1893. Under Lorentz’s direction he per formed the experiments which showed that a source of light in an intense mag netic field possessed spectral lines that were split into three components. This Zeeman effect (which Faraday [474] had sought and failed to find) confirmed Lorentz’s suggestion that the atom consisted of charged particles whose os cillations could be affected by a magnetic field. The nature of the effect could be used to deduce details concerning the fine structure of the atom and also to deduce other details concerning the magnetic fields of stars. A small thing like a single line becoming a triplet could thus at once enlighten the microcosm and mac rocosm. The initial announcement of Zeeman’s discovery attracted little attention, how ever, till Kelvin [652] publicly noted its importance. He gained a professorial post at the University of Amsterdam in 1900, and in 1902 Zeeman shared the Nobel Prize in physics with his teacher, Lorentz. [946] NAGAOKA, Hantaro Japanese physicist
Nagaoka graduated from the Univer sity of Tokyo in 1887 and then went on for further training to Germany and 605 [947] HARDEN
HARDEN [947] Austria-Hungary, after having obtained his Ph.D. He was interested in atomic structure. It had already been discovered that atoms contained negatively charged elec trons and J. J. Thomson [869] had suggested that the atom was a sphere of positively charged matter on the surface of which electrons were placed. Nagaoka rejected this view and felt there was a positively charged object at the center of the atom and that the electrons circled it as planets circled the sun, or as its rings circled Saturn. This Saturnian model was advanced in 1904 and it showed remarkable pre science. Within two years, Ernest Rutherford [996] showed that there was indeed a central positively charged nucleus in the atom. The notion of electronic satellites, however, was too simple. Once Bohr [1101] applied quan tum mechanical considerations to the atom, electrons were found to behave far differently from tiny “planets.” [947] HARDEN, Sir Arthur English biochemist Born: Manchester, Lancashire, October 12, 1865 Died: Bourne End, Buckingham shire, June 17, 1940 Harden, the son of a businessman, did his undergraduate work at Owens Col lege in Manchester but went to Germany for further education, obtaining his doc tor’s degree at the University of Erlan gen in 1888. He spent ten years teaching at Owens College and engaged in the writing of textbooks. The turning point of his life came when he grew furiously interested in Buchner’s [903] discovery that alcoholic fermentation could be made to proceed without the presence of living cells. In 1897 he joined the Jenner Institute of Preventive Medicine and began re search into alcoholic fermentation. In 1904 he placed an extract of yeast inside a bag made of a semipermeable mem brane and placed that bag in pure water. In this way small molecules in the ex tract pass through the membrane and are gone while large molecules cannot pass through the membrane and remain be hind. The process is called dialysis and the technique stems back to the days of Graham [547], Harden found that when he did this, the activity of the yeast enzyme was lost; it no longer fermented sugar. However, if he added the water outside the dialyz ing bag to the material within, activity was restored. The yeast enzyme, it seemed, consisted of two parts, one small-molecular in nature, the other large-molecular. If the material within the bag was boiled, then activity was lost even if the outer water was added. The large portion of the molecule was therefore, in all probability, protein. The small molecule survived boiling and was, in all proba bility, not protein. The latter was the first example of a “coenzyme,” a small molecule not protein in nature, which is necessary to the working of an enzyme, itself a protein. The chemical nature of the coenzyme was studied by Euler-Chelpin [1011], among others, and it became clear that the vitamins, whose discovery begins with Eijkman [888], are necessary to life only because they formed portions of coenzymes. Since enzymes, being cata lysts, are needed only in small quantities, coenzymes and, therefore, vitamins are also needed in only small quantities. This explains why a substance may be essential to life and yet be necessary only in traces. The same rationale accounts for the fact that minerals like copper, cobalt, manganese, and molybdenum are necessary in traces. They too form part of coenzymes. Harden noticed another interesting thing. Yeast extract breaks down glucose and produces carbon dioxide quite rap idly at first, but as time goes on the level of activity drops off. The natural as sumption is that the enzyme breaks down with time. In 1905, however, Har den showed that this could not be so. If he added inorganic phosphate to the so lution, the enzyme went back to work as hard as ever. This was a strange finding, Download 17.33 Mb. Do'stlaringiz bilan baham: 
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