0
PIERRE CURIE-An Appreciation of his Scientific Achievements HERBERT S. KLICKSTEIN' Dorchester, Massachusetts
Pierre Curie
(1906)
w& a physician and in turn the son of a physician. Another son, J a c q u e ~ ,was ~ three and a,half years older. It was a close family, bound by deep affection and kindred intellects. While Pierre was still a child, it became apparent that he was of an independent and dreamy nature. His parents recognized his inability t o fit into a prescribed school and took his education upon themselves. I n addition, from many excursions into the surrounding countryside, Pierre Curie acquired a deep appreciation for natural science., The quiet it offered for serious contemplation complemented his personality. His interest in natural phenomena was further encouraged by his father and brother. This early education was supplemented by a private tutor, A. Brazille, who taught him Latin and mathematics. Brazille recognized unusual latent abilities in Pierre. This unconventional schooling culminated in 1875 with the award of a Bachelier 6s Sciences, when he was 16. Pierre Curie then went to the Sorbonne for further studies. Here he assisted Le Ronx4 of the School of Pharmacy in the preparation of physics lectures. It was then that he also began collaborative investigations with Jacques, who was a chemical' assistant a t the school. In 1877, Laving satisfactorily completed the prescribed curriculum, he received the Licencid es Physique (Master's degree). The ability of Pierre attracted the attention of De-
Oil Port.ait by V. Shhurkin
VVIm THE advent of the "Atomic Age" *an interest has developed in the historical sequences that led t o its inception. One of its most fundamental concepts was radioactivity which resulted from the discovery of radium by Pierre and Marie Curie (1896). It's story has been retold time and again,%but few give any indication of the genius of Pierre Curie nor realize that he was already a distinguished scientist prior to marrying Marie. Pierre Curie was a great scientist whose fundamental discoveries in the fields of piezoelectricity, crystals, radioactivity, and symmetry have contributed a great deal to the advancement of modern physics and physical chemistry. Unfortunately his early death prematurely ended his work, but a review of the contributions he made in his short life'span leaves little doubt as to his genius. Pierre Curie was born in Paris on May 15, 1859. His family were of the petite bourgeoisie. Eugene, his father,
1 There have been many accounts written dn the Curies but few are authoritative. Most emphasize the discovery of radium and little else. The following, which have been used in part in preparing this paper, are recommended for future reference: P., "Pierre Curie," Rw. mois, July 10, 1906. (I) LANGEYIN, (2) "Oeuvres de Pierre Curie," Gmthier-Villars, Paris, 1908. (3) Crmrm, M., "Pierre Curie intime,"'Rw. Bleue, 61, 217 (1923). (4) CURIE,M.,"Pierre Curie," Pay& PaTis, 1924, translatedinto AND VERNON KELLOO,with an English by CHARLOTTE introduction by MRS. WILLIAMBROWNMALONEY and autabiographicd notes by MARIECWIE, "Pierre Curie," The Macmillan Company, 1923, Reissue, 1932. (5) "Le mouvement scientifique contemprain. en France: Les Sciences Physico-Chaiques," Payot, Paris, 1925. (6) CURIE,E., "Madame Curie (1867-1934); translated by V. S~EAN Doubleday , Doran, Garden City, N. Y., 1937. (7) GIVELET,A,, "Pierre Curie et les pvemihres ddcouvertes de 1'6nergie alomipue," Flambeaux, Paris, 1946. SPaul-Jrtcques Curie, born in Paris in 1855, worked with Friedel on pyroelectricity and collaborated with Pierre on the discovery of piezoelectricity (1880). In 1893 he became head lecturer in mineralogy at the University of Montepellier and retired because.of deafness in 1925. He died in 1941. His son, M&uriceCurie (1888- ), hss been active in radioactive work. ' Fran~oisP. Le Roux (1832-1907), Professor of Physics and Superintendent of the School of Pharmacy.
Present address: University of California, Berkeley, California. 27'8
JUNE, 1947
279
difficult because of the small deformations encountered. A small room was put a t their disposal by Desains and Mouton. Other papers followed (1881-82) verifying Lippmann's prediction. It was shown that quartz had a piezoelectric coefficient of the same value for the direct and converse effect. A practical application was made by Pierre and Jacques Curie in the design of a piezoelectric quartz electrometer. Unfortunately their close collaboration lasted but a few years, for in 1883 they separated. Jacques went to the University of Montpellier as chief lecturer in Mineralogy and Pierre became director of laboratory work a t the School of Physics and Chemistry of the City of Paris. The o u t put of such outstandi~gexperimental results was remarkable, for Pierre was but 21 and Jacques 25. They were later awarded the Plant6 prize for their work. The School of Physics and Chemistry was destined to he Pierre's home for 22 years. Initially there was little opportunity for experimental work, for the complete organization of the laboratory was in his hands. Although scarcely older than his students he was treated with respect, for his simplicity and modesty drew them close. He gave freely of his time and experience. Since he could not immediately resume his experimental re. search he again took up his mathematical studies. I t was a t this period that he becaine engrossed in the theoretical relations of crystallography and physics. He published (1884) a paper, "Sur les questions d'ordre: Rdpdtitwns," which was one of his first fundamental reports on the symmetry of crystals. I n the same year another memoir presented a general discussion of the concept of symmetry and its repetitions. An important study an the formation of crystals and the capillary constants of~theirdifferent' faces also appeared. The series of theoreticgl investigations published in 1893-95 yielded a general enunciation of the principle of ~ y m m e t r y : ~"When ( ~ ) certain causes produce certain effects,the elements of symmetry in the causes ought t o reappear in the effects produced.:': ,When certain effects reveal a cert*in dissymmetry, this dissymmetry should be apparent in the causes which have given 6 Paul Quentin Desrtins (1817-85), physicist, professor at the them birth.. . .The converse of these two statements Sorbonne, made extensive investigations of the infrared spectrum. does not hold, a t least practically; that is to say, the 6 Jean Louis Mouton (1844-95), a distinguished physicist who died almost immediately after writing his doctoral thesis (see effects produced can be more symmetrical than their M. CAULLERY, "French Soience and its Principal Discoveries causes." The results in this fieid are of a fundamental since the 17th Century," New York, 1934). nature. Although he was later t o leave the study of ' ' A full chronological bibliography of Pierre Curie's.pnhlicacrystals, it always remained a close interest. In part, tions is given at the conclusion of this paper. it was his intimate knowledge of nature that suggested CADY,G. C., "Piezoelectricity," McGraw-HillBook Company the various manifestations of symmetry. Inc., New York, 1946, p. 2. Several years passed before any laboratory or funds ' Wilhelm G. Hankel (1814-99), a German physicist who recognized that the effect would obey its own hws and proposed were alloted t o Pierre for experimental research, and thename "pioeoelectricity" (fromtheGreek "to press" and "fire") then it was only through the aid of Schutzenberger.lz which wa4 acceptable to all. For working space Pierre Curie used an outside corridor lo Charles Friedel (1832-99), a French chemist and mineralagist, who worked on pyroelptric properties of crystals, artificial and sometimes, when not in use, the students' laboraproduction of hinerals, ketones, and aldehydes and investigated tory. An occasional return on vacations to work with with James Craft the synthesis of arofnatic homologs (Friedel- Jacques brought forth further reports on piezoelecCraft Resotion) and synthesized glycerin. Gabriel Lioomann (1845-1921). .. . . a French nhvsicist . , who ore- tricity (1889). Pierre Curie's resumption of laboratory
sains; the director of the University laboratory, and Mouton,' the assistant director. The latter extended an appointment as physics laboratory assistant to Pierre, which he accepted. It was in this position that Pierre Curie commenced original experimental work. The first productive research was with P. Desains on the determination of the wave lengths of infrared rays employing a novel system, a. thermoelectric element and wire grating. The results were incorporated in a paper, "Recherches sur la determination des longueurs d'onde des rayons calorifipes b basse temperature," which appeared in the Comptes Rendus (1880).1 It was his first published work. This was followed, in the same year, by two additional publications which emanated from the collaborative investigations with Jacques. They had discovered that "some crystals when compressed in particular directions show positive and negative charges on certain portions of their surfaces, the charges being proportional to the pressure and disappearing when the pressure is withdrawn."S The name "piezoelectricity" was given to thenew effect.* This was no accidental discovery. Pierre Curie's previous studies of pyroelectric phenomena and the symmetry of crystals enabled them to predict such an occurrence. The work was accomplished a t Friedel's'Q laboratory where Jacques was preparator. I n the first memoir the preparation of flat plates cut with the proper orientation is described. The effect of pressure on crystal-s of zinc blende, sodium chlorate, boracite, tourmaline, quartz, calamine, topaz, tartaric acid, cane sugar, and Rochelle salt is presented. The brothers continued their study of the new phenomenon, establishing the quantitative laws that govern the effeet. Accurate measurements of the piezo effect in quartz and tourmaline were made (1881). A natural contmuation was the elucidation of the converse action, the production of a compression in piezoelectric crystals by an electric field. Actually the Curies had not foreseen this, but it was predicted by Lippmann" on the basis of the thermodynamic principles. This phase of thg? research was
scnted 1l.e prim iple of the eanscrvation of cleerrieify, deviwtl x mctl~ndoieolorpl,oto~aphg,i~dvcnrcdthe capillary electrometer, nr.d war, the Sooel Prme ~n physics in 1008.
l P Paul Schutreal~er~rr (IS27 97), a French eherrkr wlmir c l d n.ork wai in physiological chrmirrry, irrwentation, and dyesrurT*.
JOURNAL OF CHEMICAL EDUCATION
280
investigations is marked by a study of periodic precision balances for least weights. This work produced a particularly valuable instrument. The inquiry covered the theory of damped movements and oscillation. I t was done with student assistants. A simultaneous study of the magnetic properties of materials as a function of temperature (to 1400°C.) was instigated in 1891. The work covered five years. The summation was presented by Pierre as a Doctor's thesis before the Faculty of Science of the University in 1895. It exemplifies the full experimental maturity of its author. The Curie Law states: "The properties of diamagnetic materials are in general independent of temperature and field strength, but for paramagnetic compounds, the susceptibility is nearly inversely proportional to the absolute temperat~re."'~ Pierre Curie was 35 when he obtained his doctorate. It mattered little for his only passion was research. His refusal of academic honors and his reluctance to solicit advances were responsible, in part, for his lack of means. Despite poor facilities and inadequate support, he had established himself as a scientist of the first order, not only in France but in other countries. It was through the intervention of friends that a chair of physics was offered to him in 1895.
In 1894, shortly before receiving his doctorate, Pierre met Marie Sklodo~ska,'~ a young Polish student a t the Sorhonne. Curie was not readily affected by women, for his deep interest in science had long ruled out marriage. From childhood he was an introvert and gave little of himself to others. Of those few who intimately knew him, he bestowed without reserve a rich full devotion. With Marie it was different. The friendship that grew into a deep love has now become a classic. "The conjuncture which brought together from t v o very distant points (Paris and Warsaw) these two individuals, as similar as they were rare, is truly miraculous. Though brought up apart and in very different ways, they were as alike with regard to essentials as two individuals can possibly he. Their irrationalism, their passionate love of truth and of science, their indifference to money and fame, their innate austerity were equally deep and gen~ine."1~They were married in July, 1895. At this time, ''Pierre Curie had a very individual charm made up of gravity and careless grace. He was tall. His clothes, cut on ample old fashioned lines, hung a hit loosely about his body, but they became hi; he had much natural elegance. His hands were long and sensitive. His regular, almost motionless face, lengthened by a rough beard, was made beautiful by L a GLASSTONE, S., "A Textbook of Physical Chemistry," D. his peaceful eyes with their incomparable look, deep Van Nostrand C o m ~ m vInc.. . New York. 1946. D. 611. and serene. detached from all things. Althoueh this man maintained a constant reserve and never lifted his voice, it was impossible not to notice his expression of rare intelligence and di~tinction."~ ' After their marriage, Pierre again resumed his work on crystals while Marie prepared for examinations. The preparation of the new course ~onsumedmuchtime. His comprehensive lectures on crystallography and electricity found no equal in Paris. Consequently, his experimental work was once more curtailed, as the few publications during this period attest. The birth of a daughter, Irene,'# in September, 1897, added to his financial responsibilities. Immediately after the birth of ~renk,Marie returned to the laboratory. Her imagination was excited by the experiments of H. Becquerel" who had accidently discovered that uranium compounds emitted a penetrating radiation. She decided to make the study of this phenomenon, which she later named radioactivity, the subject of her doctoral thesis. After the examination of many salts, measuring the effect with a Curie electrometer and ~ i e e oauarte. she investipated the DroDer-
-
Eronre Medellion Head of Pierre Curie
-
'* Marie Sklodowska (1867-1934) was born in Warsaw where she studied with her father. She went to the Sorhonne in 1891 d e r e she met and married Pierre Curie. She received the dactorate in 1904 m d succeeded Pierre as Professor of Physics at the Sorbonne (1906). She won the Nobel Prize in chemistry in 1911. l6 SARTON, G., ISi8, 28,480 (1938). l6 Irene followed her parents' footsteps in physics. She married Frederic Joliot, a. physicist. Together they won the Nobel Prize in physics (1935): They have two children, Pierre and Jeannine. '7 Antoine Henri Becquerel (1852-1908) was the son of Edmond Becquerel(1821-91) and the grandson of Antoine Becquerel (1788-1878), both physicists who aka made important contrihutions to chemistry and physica.
ties of some miherals. The activity of pitchblende, a uranium ore, was found t o be so great that she suspected the existence of some new element. Pierre, who had followed his wife's work with keen interest, abandoned his crystal work to aid in the isolation of the unknown element. After many tedious fractionations, the existence of two new elenients became a certainty. The first, polonium (named after Marie's homeland), was announced (July, 1898) in a joint paper, "Sur une s b stance nouvelle radioaclive eontenue duns la $echblelzde." The discovery of radium was reported in December. Their work was handicapped throughout by the lack of facilities. Most of the investigation was done in an abandoned shed which gave little protection from the weather.18 As the work progressed it became apparent, because of its increasing magnitude, that i t should he divided. It was agreed that Pierre would investigate the radioactive properties of the new compounds while Marie would continue the purification of the salts with the isolation of the elements as an ultimate goal. In 1899 Pierre and Marie Curie published a paper on induced radioactivity. This was followed, in the same year, by still another joint effort on the chemical effects of the radiations. Pierre also independently studied the action of magnetic fields on radium emanations. At the Congress of Physics in 1900 a general review of their researches was presented. Although the work had been split, i t was still too much for them both so several collaborators were invited. George Sagnac,'9 a physicist who was interested in the relation of X-rays to radioactive radiations, joined the Curies in 1900. He worked with Pierre on the determinations of the electric charge carried by the secondary rays. Another, Andre Debierne,ZQ also worked with Pierre and Marie. He discovered actinium. At this period an increase in income became imperative. An assistant professorship a t the Polytechnic School (March, 1900) was accepted. Shortly after, an offer of the chair of physics a t the University of Geneva was made. Due to the interrnptiong such a move would cause in their work, it was refused; however, a position t o teach a general science mwey course a t the Sorbonne arose, to which Pierre was appointed. Marie further supplemented their income by teaching physics a t a girls' normal school. Although Pierre's new work was fatiguing, he found some time to continue his investigative pursuits. A paper on induced radioactivity with Debierne appeared in 1901. Further studies on the same subject, work on the conductibility of dielectric liquids as affected by radium and X-rays,-the laws that emanations, and the discovery of the heat liberated by '8 It has been suggested that the violent ventilation of the shed by winds was chiefly responsible for saving the Curies from Bulletin of the Polish radium poisoning [see W. SWIETOSLAWSKI, Institute of A ~ t and s Seienees in America. 3. 208 (1945)l. ~ e o r i eM. Ssgnac,(1869-1928), later &ofess& of'~hysicsat the University of Lille and Professor of Physics in the University of Paris. 2D Andre Louis Dehierne (1874), a French chemist, discovered the element actinium and later collaborated with Marie Curie on the isolation of radium.
radium rere some of the problems that occupied him a t this time. I n addition, he reported with others on the diffusion of radium emanations in air, on the radioactive gases in the thermal springs, on the physiological effects of the radium rays, and on an apparatus for the determination of magnetic constants. The first years of the 20th century were difficult for Pierre but appreciation was not far off. I n 1903 the Royal Institute of London invited him to lecture on radium. While there, he collaborated with Dewar2' on a study of the discharge of heat by radium a t very low temperatures and upon the formation of helium. Almost simultaneously the Davy Medal of the Royal Society and the Nobel Prize in physics (1903, with H. Becquerel) were awarded to the Curies. Due to Pierre's poor health because of overwork, it was June, 1905, hefore they could go t o Stockholm to accept the award. Pierre gave the Nobel lecture.22 The money they received permitted Pierre to turn his teaching duties over to Paul LangeviqZaa former pupil. Unfortunately the publicity brought new demands on his time. A second daughter Evez4was born in 1904. France suddenly realized Pierre's genius and hastened to create a new chair of physics for h i a t the Sorbonne (1904). Again the change with its new duties kept Pierre from his research. It is little wonder that the year 1905 saw no new publications. Slowly he returned to his study of the radioactive gas discharge from mineral water. "Sur la radioactivitB des gas qui prm'ennent de l'eau des sources thermales" was his last paper, for on April 19, 1906, he was instantly killed by a heavy wagon. It was 8n unfortunate fate that the flow of his creative efforts should ceme so prematurely. .. The genius of Pierre Curie, aside from his radioactive studies, was shown in his early independent work on piezoelectricity, crystal bymmetry, magnetic properties, etc. As to the share he contributed t o the investigations with Marie, it is best to recall the words of Eve Curie: We cannot end we must not stt&pt to find out what should he credited to Marie and Pierre--it would he exactly what the husband and wife did not want. The personal genius of Pierre Curie is known to us by the origind work he had accomplished before his collaboration. His wife's genius appeam to us in the first intuition of the discovery, the brilliant start; and it was to reappear to us again. Solitary, when Marie Curie, the widow, unflinchingly carried the weight of a new science and conducted it, through research, step by step, to its harmonious expansion. We therefore have formal proof that in the fusion of their two efforts, in this superior alliance of man and woman, the exchange was equa1"e)
" James Dewar (1842-1923), a Scottiah chemist and physicist, who worked on spectroscopy and the specific heat of hydrogen. He first produced liquid hydrogen, devised the Dewar flask, and studied properties of materials a t low temperatures. NOR~TEDT, P. A,, "Leg P T ~N Zobel a 1903," Stockholm. 1906.
.
Paul Langevin (1872-1946), a French physicist known for his application of pieeoelectricity to submarine detection (World War I); he etudied secondary X-rays, the properties of ions in gases, the kinetic theory of gases, magnetism, and relativity. Eve Curie became a concert pianist as well as the author of many hooks. One of the best is the splendid biography of her mather.P"'
