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631 [991] POPE
RICKETTS [992] Perrin’s other major work was also on particles, but less directly. In 1905 Ein stein [1064] had worked out the equa tions governing Brownian motion on the assumption that it was the result of a bombardment against small suspended particles by the water molecules sur rounding it. The way the particle was maintained in suspension against the force of gravity was, according to the equation, partly dependent on the size of the water molecules. In 1908 Perrin set about determining that size by observa tion. Through a microscope he counted the number of small particles of gum resin suspended at different heights in a drop of water. He found that the manner in which the numbers dropped off with height fitted in exactly with Einstein’s equation and, for the first time, the ap proximate size of atoms and molecules could be calculated from an actual ob servation. He described his work in a book he published in 1913, which was well enough written to sell thirty thou sand copies. At last, the tiny entities, whose existence had been accepted al most on faith for the century since Dal ton [389] had promulgated the atomic theory, took on a patently real existence. Boltzmann was right and even the die hard Ostwald had to admit that atoms were real objects and not just convenient fictions. In 1941, after France’s disastrous de feat by Nazi Germany, Perrin (who had been an active anti-Fascist) left for the United States. There he used his influence to support the De Gaulle movement, which maintained a continu ing French resistance outside the country itself. Perrin, over seventy years of age by then, did not live to see his country liberated. After the war, his remains were re turned to France for honored burial. [991] POPE, Sir William Jackson English chemist Born: London, October 31, 1870 Died: Cambridge, October 17, 1939
Pope was an actively intelligent young ster who was encouraged by his parents. (They allowed him to set up a small chemical laboratory in his room.) He be came a skilled photographer—another hobby—and learned several languages with ease. Nevertheless, though he left school in 1885 with good marks, he had not remained long enough to pick up degrees.
During the 1890s Pope served as assis tant to Kipping [930]. In 1899 he pro duced an optically active compound that contained an asymmetric nitrogen atom, but no asymmetric carbon atoms. This proved that the Van’t Hoff [829] theory applied to atoms other than carbon. In 1901 he became a professor of chemistry at the University of Man chester and went right on with his work. By 1902 he had prepared optically active compounds centered upon asymmetric atoms of sulfur, selenium, and tin. Later, he demonstrated that compounds with out asymmetric atoms of any sort, but asymmetric as a whole, through the influence of the steric hindrance first ex pounded by Viktor Meyer [796], could also be optically active. He thus changed the notion of stereoisomerism from its original narrow coverage to the broad and general concept that now prevails. He received the Davy medal in 1914 and was knighted in 1919. During World War I, Pope had the rather dubious honor of developing methods for manufacturing mustard gas in quantity. It was the most fearful of the poison gases used in that war and was to stand as a peak in military horror till the development of the nuclear bomb in World War II. [992] RICKETTS, Howard Taylor American pathologist Born: Findley, Ohio, February 9, 1871
Died: Mexico City, Mexico, May 3, 1910
Ricketts, the son of a grain merchant, graduated from the University of Ne braska in 1894. By then his family had lost its money in the Panic of 1893 and 632 [993] GRIGNARD
GRIGNARD [993] Ricketts had to work his way through medical school, and broke down (tempo rarily) under the strain in his third year. He gained his medical degree at Northwestern University in 1897 and followed that up with further training in Europe. He joined the faculty of the University of Chicago in 1902, then in vestigated Rocky Mountain spotted fever and in 1906 showed that it was spread by cattle ticks. He was the first to locate the microor ganism that caused it, and it proved to be a most unusual one. It was smaller than bacteria generally and was not a truly independent organism, for it resem bled viruses in being able to grow only within a living cell. It was larger than the ordinary virus, however. It seemed very much like a creature intermediate in position between bacteria and viruses. Ricketts went on to study typhus, an other disease caused by such a microor ganism, and as Nicolle [956] was doing in Tunis he showed that it was trans mitted by the body louse. In 1911, in Mexico City, while experimenting with the disease, Ricketts contracted it and died. Mexico observed three days of mourning on his behalf. After his death the microorganisms of the type that caused typhus and Rocky Mountain spotted fever were named rickettsia in his honor. [993] GRIGNARD, François Auguste Victor (gree-nyahri) French chemist Bom: Cherbourg, Manche, May 6, 1871
Died: Lyon Rhone, December 13, 1935
Grignard, the son of a sailmaker, won several prizes for his studies as a young ster, and when he entered the University of Lyon, he studied mathematics. He finally obtained his degree in that sub ject, although he did not particularly ex cell in it. He had a poor opinion of chemistry at first, but casual contact with work in a chemical laboratory brought a quick conversion and mathematics had to do without him. He did not even un dertake physical chemistry, where math ematics might have been useful, but plunged into organic chemistry, to which in those days mathematics was a stranger. Grignard embarked upon a course of experiments in which he was attempting to add a methyl group (consisting of a carbon atom and three hydrogen atoms) to a molecule. The problem was to find the right catalyst. Zinc shavings worked in some cases, but not in the one he was dealing with. Magnesium metal seemed to offer hope but results were irregular and undependable. Frankland [655] had prepared combinations of zinc with or ganic compounds by using diethyl ether as the solvent, and Grignard wondered if he couldn’t do the same with magnesium and if the resulting compounds might not be useful. It was a lucky stroke of intuition, for the trick worked. Furthermore, this de vice proved extremely versatile and mag nesium-ether in combination with a number of compounds produced a whole series of what are now known as Gri gnard reagents. A powerful new weapon had been added to the armory of the synthetic chemist. The Grignard reagents were first an nounced in 1900 and Grignard presented the work as his doctor’s thesis in 1901. In no time at all, many chemists, includ ing Grignard himself, were investigating Grignard reagents in all directions. Within five years, two hundred papers had been published on the subject. The usefulness of the device was such that in 1910 Grignard received a professorship in chemistry at the University of Nancy and at Lyon in 1919. In 1912 he was honored with the Nobel Prize in chemis try, sharing it with Sabatier [856]. When World War I broke out, Gri gnard was called to service as a corporal, but he was quickly put into chemical war work. He worked out methods for preparing phosgene, a poisonous gas, and for detecting the first traces of mustard gas, another poisonous gas. After the war Grignard returned to organic re search.
633 [994] BODENSTEIN WRIGHT
[994] BODENSTEIN, Max (boh'den- shtine) German chemist Born: Magdeburg, July 15, 1871 Died: Berlin, September 3, 1942 Bodenstein, the son of a brewer, like Pope [991] started young as a chemist by setting up a laboratory in his room. He attended the University of Heidelberg and did his doctoral research under Vik tor Meyer [796], receiving his Ph.D.
From his doctoral work on, he was chiefly interested in chemical kinetics, the study of the rates of reactions. He concentrated on apparently simple reac tions such as the decomposition of hy drogen iodide, or the combination of hy drogen and chlorine. He found, about 1920, that reactions did not usually proceed in a simple way and, in particular, he was the first to see the necessity of postulating a “chain re action”: one in which the product of a molecular change serves to bring about a similar change in another molecule. Such chain reactions can thus continue with explosive rapidity. A thorough understanding of chain re actions led to better methods of plastics formation, and the analogous nuclear chain reactions led, of course, to the nu clear bomb. In 1923 Bodenstein succeeded Nemst [936] (who had originally suggested the possibility of chain reactions) as head of the Institute of Physical Chemistry. [995] WRIGHT, Orville American inventor Born: Dayton, Ohio, August 19, 1871 Died: Dayton, Ohio, January 30, 1948 Orville and his older brother, Wilbur [961], were sons of a minister and lived the most proper lives imaginable. They neither smoked, drank, nor married and always wore conventional business suits even when tinkering in a machine shop. Neither had more than part of a high school education, so they were quite in the tradition of the American inventive tinkerers who make instinct, intuition, and endless intelligent effort replace theory—after the fashion of the greatest noneducated intuitive genius of them all, Edison [788], Orville Wright was a champion bicy clist and so the brothers went into the bi cycle repair business, which gave full vent to their mechanical aptitude. An other hobby was gliding, which, in the last decade of the nineteenth century, had become a most daring, yet practical, sport, thanks to Lilienthal [793]. The Wright brothers followed Lilienthal’s ca reer, read his publications and those of Langley [711], and felt the stirring hope of manned flight grow. It was Lilienthal’s death in 1869 that inspired them to begin their own experimentation, for they thought they could correct the er rors that had led the German to his end. The Wright brothers combined their two hobbies by making every effort to equip a bicycle with wings and place an internal-combustion engine aboard to turn a propeller. They made shrewd cor rections in design and invented ailerons, the movable wing tips that enable a pilot to control his plane. That served as their original patent. In addition, they built a crude wind tunnel to test their models; they designed new engines of unprece dented lightness for the power they could deliver; they produced engines, in fact, that weighed only seven pounds per horsepower delivered. Naturally, in any aircraft, lightness is at a premium, and the engine is about the most difficult ob ject to make light. The Wrights’ feat in achieving this was an important step in making powered air-flight possible. Their entire eight-year program of research cost them about $1,000. On December 17, 1903, at Kitty Hawk, North Carolina, Orville made the first airplane flight in history—a powered flight as opposed to mere gliding. He remained in the air for almost a minute and covered 850 feet. There were only five witnesses and this first flight was met with absolute lack of interest on the part of the newspapers. In fact, as late as 1905, the Scientific American magazine mentioned the flight only to suggest it
[996] RUTHERFORD RUTHERFORD
was a hoax. In that year, however, the Wrights made a half-hour, 24-mile flight. Slowly, though, the fact that airplanes existed penetrated the realization of the world. Orville flew for an hour in 1908. The first flight across the English Chan nel in 1909 stirred the public, and the aerial dogfights of World War I lent a new and spurious glamour to the dread ful business of war. However, it was Lindbergh’s [1249] solo flight across the Atlandc in 1927 that made it quite obvi ous that the airplane was here to stay. Orville lived to see airplanes drop atomic bombs on Hiroshima and Naga saki. His brother Wilbur was less, or more, fortunate, depending on one’s out look. Orville was elected to the Hall of Fame for Great Americans in 1965. [996] RUTHERFORD, Ernest, 1st Baron Rutherford of Nelson British physicist
New Zealand, August 30, 1871 Died: London, October 19, 1937 Rutherford’s grandfather was a Scots man who had migrated to New Zealand in 1842. Rutherford’s father was a wheelwright and farmer, and Rutherford himself, the second of twelve children, worked on the farm. He showed great promise at school and in his teens gained a scholarship to New Zealand Univer sity, where he finished fourth. (One wonders what happened to the three who beat him.) In the university he became interested in physics and developed a magnetic detector of radio waves. He was completely uninterested in practical applications for his discoveries, however, and even refused to testify as an expert witness in court in a case involving radio transmission—it would have brought him out of his ivory tower. In 1895 came the turning point, for he received a scholarship to Cambridge University. This was even more of a for tunate break (for Rutherford and for the world) than it seemed, because he had ended only in second place. The first- place winner, however, refused the schol arship because he wanted to stay in New Zealand and get married. Furthermore, Cambridge had just adopted a rule that allowed acceptance of students from other universities and Rutherford was the very first to qualify under the new regulation. The news reached him, it is said, while he was digging potatoes on his father’s farm. He flung down his spade, saying, “That’s the last potato I’ll dig,” postponed his own marriage plans, and left for England. At Cambridge he worked under J. J. Thomson [869] who quickly came to ap preciate this loud, unpolished colonial with the deft hands. (Thomson himself tended to be rather clumsy in his experi mentation.) Then after a short period at McGill University in Montreal, Canada, and a trip back to New Zealand to get married, he came to England again. Hard on the heels of A. H. Becquerel [834], Rutherford began work in the ex citing new field of radioactivity. He was one of those who, along with the Curies [897, 965], had decided that the rays given off by radioactive substances were of several different kinds. He named the positively charged ones alpha rays and the negatively charged ones beta rays. These names are still used except that both are now known to consist of speed ing particles, so one often speaks of alpha particles and beta particles instead. When in 1900 it was discovered that some of the radiations were not affected by a magnetic field, Rutherford was able to demonstrate them to consist of elec tromagnetic waves and named them gamma rays. In collaboration with Soddy [1052] in 1902 and thereafter, Rutherford fol lowed up the lead given by Crookes [695], who had found that uranium formed a different substance as it gave off radiation. By subjecting uranium and thorium to chemical manipulations and following the fate of the radioactivity, Rutherford and Soddy demonstrated that uranium and thorium broke down in the course of radioactivity into a series of in termediate elements. Boltwood [987] was proving the same point in the United States at this time. Soddy was to carry this work forward and advance the no tion of isotopes.
[996] RUTHERFORD RUTHERFORD
Each different intermediate element broke down at a particular rate so that half of any quantity was gone in a fixed period. Rutherford named this fixed pe riod the half life. Between 1906 and 1909 Rutherford, together with his assistant, Geiger [1082], studied alpha particles intensively and proved quite conclusively that the individual particle was a helium atom with its electrons removed. The alpha particles were like the positive rays that had been discovered by Goldstein [811], and in 1914 Rutherford suggested that the simplest positive rays must be those obtained from hydrogen and that these must be the fundamental positively charged particle. He called it a proton. For nearly twenty years thereafter it seemed that all atoms were made up of protons and electrons in equal numbers, until Heisenberg [1245] modified the concept into the one we hold today. The electric charge on a proton is positive and that on an electron is negative, and the two charges are just equal in size so that one electron neutralizes one proton, electrically speaking. However, the mass of the proton is 1,836 times the mass of an electron. Rutherford’s interest in alpha particles led to something greater still. In 1906, while still at McGill in Montreal, he began to study how alpha particles are scattered by thin sheets of metal. He continued these experiments in 1908, when he had returned to England and was working at Manchester University. He fired alpha particles at a sheet of gold foil only one fifty-thousandth of an inch thick. Most of the alpha particles passed through, unaffected and undiverted, re cording themselves on the photographic plate behind. There were, however, pho tographic signs of some scattering, even scattering through large angles. Since the gold foil was two thousand atoms thick, and the alpha particles passed through, for the most part, undeflected, it would seem that the atoms were mostly empty space. Since some alpha particles were deflected sharply, even at right angles and more, it meant that somewhere in the atom was a very massive positively charged region capable of turning back the positively charged alpha particle. (Like charges repel.) From this experiment Rutherford evolved the theory of the nuclear atom, a theory he first announced in 1911. He maintained that the atom contains a very tiny nucleus at its center, which is posi tively charged and which contains all the protons of the atom and therefore virtu ally all of its mass. In the outer regions of the atom are the negatively charged electrons which are very light and which interpose no detectable barrier to the passage of the alpha particles. This view of the atom is the one ac cepted today, and it replaced the concept of the featureless, indivisible spheres of Democritus [20], which dominated atomistic thinking for twenty-three cen turies.
For working out the theory of radioac tive disintegration of elements, for deter mining the nature of alpha particles, for devising the nuclear atom, Rutherford was awarded the 1908 Nobel Prize in chemistry, a classification he rather re sented, for he was a physicist and tended to look down his nose at chemists. Yet great achievements still lay ahead. Rutherford employed a scintillation counter of the type first devised by Crookes to measure the amount of radio activity being produced. By counting the flashes on the zinc sulfide screen (one flash for each colliding subatomic parti cle) he and Geiger could tell that a gram of radium would eject 37 billion alpha particles per second. (Rutherford was too impatient to sit there counting flashes, but Geiger, with steady Teutonic patience, had no problem in this re spect.) A substance undergoing this number of disintegrations (of any sort, not necessarily of the type that produced alpha particles) is now referred to as a curie of that material, in honor of the Curies. This is a great deal of radioac tivity, and it is commoner to deal with material breaking down only a millionth as rapidly, this amount being a micro curie. Nevertheless, Rutherford himself is not forgotten, for a rutherford of radioactivity represents that amount of material which yields one million break downs per second. 6 3 6
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