Current Comments" EUGENE GARFIELD ,NST,T"TE FOR .sClENTlFlC lNFORMA710NQ . 3501 MARKET ST..PHlLADELPHIA. PA 19104 Linus Pauling: An Appreciation of a World Citizen-Scientist and Citation Laureate Number 34 August 21, 15X/ The lift and works of Nobel laureare Linus Pauling are examined. Using ISI" data, Pauling's scien- tific endeavors are reviewed, incluging a discussion of his most-cited works and his recent research involving quasicrystals. Pauling's comments on a wide range of topics-from the mechanisms of sci- entific discovery to the notion of scientists as political activists-are also included. The world's great men hatie not commonly been great scholars, nor its great scholars great men. Linus Pauling. For a great number of peo- ple-especially scientists-this name brings instant recognition. Pauling is one of the most written-about scientists of this century. Few people can claim to have a paper pub- lication record that spans over 60 years (with well over 700 articles), to have been awarded two Nobel Prizes, or to be in the forefront of reSearch well past the average age accepted fort emeritus status. And in spite of his activity, he remains one of the most accessible scientists in my experience. papers (with 76 other papers having more than 50 cites), while his book 7Ite Nature of the Chemical Bond and the Structure of Molecules and Crystals2 is one of the most- cited publications of all time. (Indeed, he wrote a commentary on that Citation Classic@ that we published in CC in 1985.3) Earlier this year I discussed the cid tation record of this classic work in THE SClENTISlQ. A reprint of that editorial follows.4 Many Current Contents@ (CC?) readers are aware of my long-standing fascination with both polymathic scientists and respect for those with a keen sense of social respon- sibility. Pauling is such a scientist. Among the Iields of his scientific expertise are chem- istry, biochemistry, genetics, physics, and medicine. His efforts in the cause of world peace are widely recognized. As Pauling ap- proaches his 90th birthday, it is hardly re- dundant to r&ognize an individual who has become a legend in his own lifetime. Pauling's most-cited works span six de- cades, with three publications from the 192Os, light from the 193Os, five from the !94Os, four from the 195Os, four from the 196Os, and two from the 1970s. Table 1 lists his most-cited publications and is taken from the 1945-1988 Science Citation Index@ (SC/@) database. The 1945-1954 SCIcumu- lation was recently published.5 Citation Laureate From a citationist's point of view, Pau- ling has impressive statistics: he has 26 pub- lications that have been cited in 200 or more Pauling has received many awards, in- cluding the Award in Pure Chemistry of the American Chemical Society (ACS) in 193 1; the Davy Medal of the Royal Society of London in 1947; the International Lenin Peace Prize of the Soviet government in 1971; the National Medal of Science of the National Science Foundation (NSF) in 1975; the Lomonosov Gold Medal of the Acade- my of Sciences of the USSR in 1978; the CURRENT CONTENTS@ 01989byISI@ 3 -Oliver Wendell Holmes' Table I: Linus Psuling's publications cited over ZOO tima In the SC/ *, 1945-1988. A =number of citations rcceivcd B- bibhographic data. 15,318 Pauling L. l?~e narurc o/ rhc chrmicol bond and the SINCIU~C of molrcules and cryrra~: on 863 inrrrtiucfion IO modem ~~rucrurol chcmbrry. Ithaca, NY: Cornell Univrrsity Press, 1960. 644 p. Pauling L. Itano Ii A, Singer S J & Wells I C. Sickle cell anemia, a molecular disease. Sciewr llo.s43-8. 1949. 774 Psuling L, Corey R B & B~~IISOII II R., The Structure of proteins: IWO hydrogen-bonded helical conRgu@ons of the polypcptide chain. Proc. `Nor. Acad. Sri. USA 37:205-l I, 1951, 749 Psuling L. Atomic radii and interatomic distances in merals. 1. Amer. Chem. Sot. 69.542-53, 1947. J61 Pauling I. RI Wilson E B. Introducrion 10 quantum mechanics with opplicarions to chemistry. New York: McGraw-lldl. 1935. 468 p. 456 Psuling L. The nature of the cbemicsl bond. Applicarion of results obtained from Ihc quanhmm mechanics and from 1) theory of pammagnetic rurepdbGty 10 the s(rucNrt of molecules. J. Amer. Chem. Sot 53:1367-400, 1931. 448 Psuling L. The lhevrctical prcdicuon of Ihe physical properties of many-electron atoms and ions: mole refraction. diamagnclic susceptibility, and extension in space. Proc. Roy. SOC. London Ser. A ll4:181-211. 1927. 399 Pnuling L. The strucNrc and entropy of ice and of other crystals with some randomness of atomic nrrangrmcnt. J. Amer. Chcm. Sot. 57:2680-4. 1935. .1')7 370 l'sulh~g I,. A u~&xuler ~bcory ol gcncral unerlhcsia. Science ,134: IS-21, IYbl, Pauling L. A theory of Ihe sIrucNre and process of formadon of antibodies. 1. Amer. Chmt. Sot. 62:2643-57. 1940. .,`,m 9 316 Pauling L. A resonarmg-valence-bond lhcory of metals and intermetallic compounds. Proc. Roy. Sot. London Ser. A 196:343-62, 1949. 309 Pnuling L. The rotational motion of molccilce in crystals. Phys. Rev. 36:430-43. 1930. 306 Pauling L 81 Corydl C D. The magnetic properties and s~rucNres of hemoglobin. oxyhemoglobin and csrbonmonoxyhcmoglobin. Proc. Naf. Acad. Sci. USA 22:2lO-6. 1936. 288 Pnuling L & Corey R B. Atomic coordinates and SWUCNre fsclors for two heiical configurations of polypeptide chains. Proc. Nar. Acad. Sci. USA 37:235-40, 1951, 283 Pauling L 81 Corey R 8. Conrigurnrions of polypcptide chains with favored orientations around single bonds: two ncvl pleated sheets. Proc. Nat Acad. Sci. USA 37:729-40, 195 I. 282 Cameron E, Pauling L 81 lrlbovitz B. Ascorbic acid and cancer. Cancer Res, 39:663-81. 1979. 276 Pauling L. The principles determining rhe s1ructure of complex ionic cqrslals. J. Amer. Chrm. Sot. 51:1010-26; 1929. 262 Pauling L. The diamagnetic anisotropy of aromatic molecules. J. Chem. Phys. 4:673-7, 1936. 252 Pauling L. The naNre of the chemical bond. IV. The energy of single bonds and the rclarive elecrronegauvity of atoms. 1. Amer. Chcm. Sot. 54:3570-82. 1932. 241 Pnuling L. Vimmin C and rhc common cold. San Francisco. CA: Freeman. 1970. 122 p. 233 Paulinp I,. The nxturc of the inrerslomic forces in mctnls. Phys. Rw. 54:899-W. 1938 225 Pauling L. Nature of the iron-oxygen bond in oxyhaemoglobin. Nafurr 203:182-3, 1964. ., 218 ,' Zuckrrkandl E 81 Pauling L. Evolutionary divergence and convergence in proteins. (Bryson V & Vogel H J, eds.) EvoGrg gcncs and prorciru. New York: Academic Press, 1965. p. 97-166. 211 .`Pnullng I, &`Corcy R B. Compound helical contigursdons of polypcptide chains: StNCNre of ., proteins of the alpha-kcrarin type..~~fu~~~17l:5%~1, 1953. 206 PauUng L. The sti of ions and the str-uctllrc of ionic crystals. J. AI&- them. -Sot. .* 204 a 49:765-90. 1927. Pmtllng I., Pressman D dr Grossberg A L. The serological properties of simple substances. VII A qunnlitatire theory of the intubition by haptens of the precipilalion ol' heterogeneous antisera with antigens, and comparison with experimental results for polyhaptenic simple substances and for azoproteins. 1. Amer. Ckem Sot. 66:784X. 1944. , Award in Chemical Sciences of the National Academy of Sciences of the US in 1979; and the Priestiey Medal of the ACS in 1984. Re- cently he received NSF's Vannevar Bush Award.6 He has been given honorary doctorates by over 45 institutions, including universities in Chicago, Princeton, New Haven, Cam- bridge (UK), Oxford, London, Paris, 4 Touluuse,.Montpellier, Liige, Melbourne, Delhi, Krakow,`Berlin, and Zagreb. Pau- ling has also been made an honorary mcm- ber of the academies of science of Austria, Belgium, India, Italy, Norway, Poland, Por- tugal, Romania, the USSR, Yugoslavia, and other countries:7 Pauling cofounded in 1973 the Linus Pau- ling Institute of Science and Medicine, Palo Linus Pauling Alto, California. This nonprofit organiza- tion's mission is to improve the quality of human life by prevention of disease and to relieve human stiffering through utilization of advanced techniques of chemistry, phys- ics, molecular biology, and medicine. Cur- rently, the institllte's research emphasis is on cancer, nutrition, and the aging process. ' . Pauling on Papers and Published Ideas Recently, we-spoke at' ler,igth with Pau- ling, who reflected on his long career as a scientist and scholar. The topics discussed were wide-ranging-covering his life, his works, and his views on-science. Excerpts of this conversation ' are' interspersed throughout this essay'.8 `. > Q: Whar pcrpers do you feel arc your most important works? Your most original? Your most undervalued.~ / , Puuling: Well, I think the mos! important single paper that 1 published was the "The nature of the chemical bond" in the lour- MI of rhe American Chemical Society9 in March or Apcil of 1931. The most impor- tant coll+ion of papers would be the ones that preceded it in 192810-13 and fol!owed it dealing with electronegativity scale and resonance of' `molecules among different electronic structures:l4-16 The one that per- haps hasn't been recognized so greatly for its significance tias the one that 1 published with my students and postdoc fellows in 1949 entitled "Sickle cell anemia, a molec- ular disease "17 [cited over 850 times]. It led to the development of the whole field called the hemoglobinemias and, in fact, to many other applications. My paper on the molecular basis of general anesthesia [cited almost 400 times] might be my most origi- nal.!* &: On theaiubject d-/ original ideas and publications, have you ever had any scien- tific ideas that you thought were so outra- geoMs or unusual that,you never mentioned them to anyone?' Paulingi I usually publish+ my "unusual" ideas, and, of cyurse;`there have been a few times when I was wrong. But other times I have-heard it said, or it was reported to me that it was said, that I have been right so often in:the past that I'm probably right now, too-about such ideas as the value.of high doses of vitamin C. 19 Perhaps I have had some,,outragequs ideas, but they were so outrageous that I buried them deeply in my memory. I think my answer is that I tend to publish my ideas even'though .they are quite unconventional: 0~ the lPro&ss of' Scientifk'l~iscovcry .' Pauling's career has been characterized by his capacity for quick insight into new prob- lems, his ability to recognize interrclalion- ships, and the courage to put forward unor- thodox ideas. His intuitive guesses, aidcrl by a phenomenal memory of chemical facts, have been referred to by .Pauling as the .' `sto- chastic method',' (from the Greek "apt to divine the.truth by conjecturer').20 Pauling talked about his experiences with the pro- cess of discovery. 5 , Q:, Wh& qualities 40 you think-makk great scientists? Is it necessary ihat `scientisti think un'l-o@enti&hlly' `for bieakihroughs to `yppkn?,. `. .,j " `, :,s,,, I.' 4'. .~ Pauling: Well, there.are differemkinds of great scientists; I think probably an impor- tant quality is the ability to recognize'prob- lems that might be solved if we worked hard 3 1 ; t a s r t S .r a F S il e tl ; e tc fi P 0 n il tf ti lf B P 0 - Q: HOW have yohl: b+sfI or most produc- tive, ideas come to you? Do thej come via driams, `concentr&d thought, or relaxation. `7 I/ :. ,. `_ `. Pauling: I wai one'of three-people who spoke at. a: sytiip6$tim..`Qn cieativity at the Third. ! y&d' &!dt$&>~f. iPsychiatry in M&real in 1961:.-i: `And.1 said,that often ny original ideas :have come .a$, the result If trairiing my un&nscious mind tb ,think ibgut ~.pr~blefri.$$ve as `an tixan$e the ;ne` `oii tl$,t$$$+,;general; anesthesia. I & in Boston as a niemhe; of the scientific tdviiory board .of `Mass&h&etts General !Ios#i&`in 1952, .and .&hoard was let- ured to by the profess&of anesthesiology It Harvard-Henry K. Beecher. Beecher :aid something that i hadn't known, that the noble gas xenon `can act as a general anes- hetiti agent; So I said to my son (who was studying medicine),: "How do you think Lenon cant serve' as :a general : anesthetic Igent, since-xefion doesn't form any corn- jounds in the human body? It must be some ort of a physical action+ don't understand t;" I thought about.it day after day for sev- .ral days; in the evening when I would go o t&l; Iswoliid lie'there and think about,the ,roblem.... After a while I stopped that. Xen, seven,years later, 1,was reading a sci- ntitic paper oti crystal structure, and I said 1 myself, I u~de&nd'&esthesia. I worked or, at&t a'ita? xathering data, and then I lublishkd I;;>;`&@ on "A molecular theory If gkneral'anesthesia."t* So I had trained ny unconscious mind to keep this problem n ,yiew, and,wheneuer at$qew thought en- :red.my,head, any new piece of, info-a7 .on,' I would connect it up,with that prob- :m to see if there was any connection.. . . ;y `the way, my talk'was published in the roceedings. of,the;Third World Congress f Psychiatry.23' , 6 ~.01989'by'ISI@ CURRENi CONTENTS@ On Activism and the Conduct of Science Q: In your view, should scientists become Despite nearing his 90th bit-&day, Pau- more active politically? Under what ling,is still the consuminate.scientist, and'his circumrtances? research gctivity remains influential world- Pauling: Well, of course I published niany wide. According to .ISI@ `research-front papers, and my book No More Warn' In data, Pauling has been a core author in re- several of my papers; I talked about science se&h .fronts consistently. for the past five and humanity; science,`politics, and physics; years-5 in *1984, 4 in 1985, 3.in 1986, I and the obligations of scientists. I've s&d in ,1987, and 10 in 1988. (He has;of course, that I believe scientists have the duty of help- also been a core author in earlier research ing their fellow citizens to understand the fronts, too numerous to mention here.) important problems-the scientific asp&s Table.2 identifies the ,1988 research fronts of them. Almost every problem in the world that have.Pauling as a core author.`One of today has some `scientific basis' 0;. invo!ve- the fronts, #88-1424, "QuasictystaIs," rep- ment. Sometimes it is hard.even for the sci- `resents a topic that Pauling is presently pur- entists to understand the problems. I saj that suing.24,*5 According to a-recent article in scientists should not only help educate and ~THE'SCIlZN77IsT, the LinusPauling Institute inform their fellow citizens, but alSo expresi is rankedamong the top 10 institutions con- their own opinions.... I think political ac- duct&g .resear&in this field? " c' tivity is v,ery important. A good .exam$e At present, quasicrystal research is in a was the "Stop the Vietnam War" campaign, state of flux. As is normal in ongoing re- which was finally successful. In my own search, there are differing view-points, some case, it interfered significantly with my, sci- controversial. And Pauling's view on the ex- entific work. I thought $+t the problem of istence and properties of quasictystals is nuclear war was such an important one and seen,,as contentious to some. To many peo- that the possibility of wars bet&en the great pie,, Pauling's standing viewpoints on many nations wasp now.being ruled out by the de'- topics-whether scientific or political-are velopment, cpnstruction, and stockpiles of simi!arly viewed. In the supposedly.apolit- nuclear weapons that I decided. ..I ought to ical .atmosphere of science, qauling advo- sacrifice some of my time in order to work cates activism. in this field [of helping to eliminate nuclear weapons and ,reduce the risk of war]. `. Q: IS controversy useful in `scientific research? Q: Do yorf think science has entered into'& :. era of playing for public media attention? `Panlining: I doubt,it. I would day not-so far Forexample, the idea of coldfisih, which as I am concerned-it's the problems them- has apparently been disproven. selves that interesi me, not whither or not Pnuling: No, I wrote a paper published in a matter is controversial. Nature-a letter to the editoE*-that I think Table 2: The 1988 SCrC research IIonla in which Linus Pauling is a core author. A=numbcr of core papers. B=number of citing papers. Number Nmne 88-0113 Hydrogen-bonded gstems 88-0465" Ice phase transitions, proton transfers, and dielectric-relaxation spectra 88-0474 Atomic sttucture'in metals' 86-0931 ,Mixed-valence coordination clusters 88-1424 Quasicrystals 88-1704 Electron spin resonance .88-3050 Natural bond orbitals ., 88-3306 Crystal SWcNre and bonding in transition metals 88-6699 Chemical hardness and bond dissociation energies 88-7703 Electronic polarizability of ions CURRENT CONTENTS@ 01989by.ISI@ A Ii 40 904 33 ,306 .' ./, 25` 322 4 24 51 466 . -12' 119 5 63 4 67 2 12 2 27 7 accounts for the thermal manifestations, the development of heat, and even the explo- sion. However, there have been several sci- entific developments or "pseudodevtlop- merits" that have attracted a great deal of attention, partially because of the possible great practical value. One example, of course, is cold fusion. A second example is high-temperature superconductivity. And a third is the so-called icosahedral quasicrys: tals. In the article in THE SCIENTIST, Paul J. Steinhardt [Department of Physics, Uni- versity of Pennsylvania, Philadelphia] listed about 1,500 papers that have been published [on quasicrystals], and my estimate is that about I.000 scientists have been working in this field during the last live years.... The reason for the great attention paid to this one aspect of metals science, metals and alloys and crystallography, is.. .the possibil- ity that there is a new fonn of matter. And 1 think all of these people, and the people in industry, especially, said to themselves- and even outright-that, since crystals with a fivefold axis of symmetry had not been known before, and since the electronic and physical properties of metals and alloys are the basis of tremendous industries-airplarie industries, lightweight, strong alloys indus- tries, and so on-we ought to look hard at these new kinds of crystals. Steinhardt said that over 100 different compositions of alloys, different intermetallic compounds, have now been shown to form quasicrystals. So there has been great interest, but, of course, no one has succeeded in linding any unusual electronic or physical properties of these substances. That's just what one would expect from my theory of their nature, which is that they're ordinary intermetallic compounds containing icosahedral clusters such as three of my students and I described in 1952,29 and also the magcesium-alumi- num-zinc alloy that we described in 195230--the fact that they are twins doesn't change their electronic properties or physi- cal properties significantly. So this is a for- lorn hope that these so-called icosahedral quasicrystals will have unusual'electronic or other physical properties. 8 Reflections on a Life Today, Pauling is world-renowned; how- ever, his path to get there was at times less than auspicious, due in part to financial hardship as a result of his father's death when Pauling was nine years old. Dcsbite this, as well as his not receiving a high- school diploma, he received his BS in chem- ical engineering in 1922 from Oregon Agri- cultural College, Corvallis. To help support himself and his mother, Pauling worked in a dormitory kitchen and graded papers. In 1925 he was awarded a PhD degree from the California Institute of Technology (Caltech), Pasadena, SU~VM cum laude.3l During 1926 and 1927, Pauling visited Europe on a Guggenheim Fellowship, study- ing quantum mechanics with Arnold Som- merfeld in Munich, Germany; Erwin Schr& dinger in Zurich, Switzerland; and Niels Bohr in Copenhagen, Denmark. From there, his scientific career took off. Q: If you were studng over today, whur fields ofscientijc endeavor would you par-, ricipare in? Would lhey De the some as those you have been and are working on? Pauling: Well, I have been very fortunate in my life. 1 had some difficultie&`bf course-financial difficulty-when I was a boy, and there was a question as to whether I would go on to college or not. After some struggle I succeeded in doing that--getting an education. I was very fortunate in going to Caltech in 1922. I think there is no place in the world that I could have gone to that would have been better in preparing me. In general, I had good luck. I was fortunate in that Professor Arthur Amos Noyes of the Chemistry and Chemical Engineering Divi- sion at Caltech wrote to me to say that he thought that I should work with Roscoe Dickinson in the field of X-ray crystallog- raphy. I don't know why he selected me from among a half-dozen new graduate SN- dents that he hadn't seen, to make that sug- gestion. But he did, and 1 couldn't have had a better field of work to get going on, with such a powerful technique. I was able to re- 61989 by ISI@ CURRENT CONTENTS@ CURRENT CONTENTS@ ., 0989 by ISI@ late to problems 1 was interested in-the mo- lecular basis of chemistry. I was able to solve problem after problem every few months as a graduate student. And, of course, I was fortunate in being around just as quantum mechanics was being developed. I arrived in Germany on my Guggenheim Fellowship just about simultaneously with the publication of Schrijdinger's first paper on wave mechanics. I arrived at the end of April 1926, and I even had a paper on quan- tum mechamcs published in 1926. And, of course, several in 1927 and 1928 and from then on. Of course, I was fortunate in hav- ing married the right person, in having been picked out by the right young woman. I don't think I could have had a better career for myself, and, of course, I didn't really plan it.. . . I think it was line that 1 spent much of my earlier years in mathematics and theo- retical physics. My PhD degree-1 ran across my diploma a few months ago and noticed that it said "for his research in phys- ical chemistry and mathematical physics." I still think that's a fine basis. There are many physicists who have as good a back- ground in mathematics and physics as I have. I differ from most physicists of a gen- eration or two ago in having had a tremen- dous background of knowledge in chemis- try, too. Q: Of the Nobel Prizes that you have won, does one have more meaning for you than the other? Put&g: I was asked that question on the 10th of October 1963 by a reporter-it might have been UPI (this is the same day the Nobel Peace Prize was awarded to me32). I have been asked it every once in a while. . . . And I say, well, 1 was pleased to have re- ceived the Nobel Prize in chemistry in 1954. I wasn't sure I was going to get it because it seemed to me that I hadn't made a single great discovery. I made a lot of small dis- coveries that all together constituted the for- mulation of a new kind of chemistry, start- ing in 193 1 [with] my first paper on quan- tum mechanics, and the chemical bond.15 But I received it, and I had just been enjoy- ing myself-you know, doing chemistry, trying to solve problems-which I still find the most pleasurable activity. So I was pleased that 1 received the Nobel Prize in chemistry, but I value the Nobel Peace Prize more. I wasn't especially interested in po- litical action or in working for world peace up to 1945. I didn't see any way in which I could do anything that would be signifi- cant. I thought that war institutionally was going to be with the human race forever (or at least in my lifetime), but when atomic bombs came along, I thought here-and my wife and I decided too-that I should sacri- fice my scientific Fori. I thought here is the possibility of, eliminating war- from the world. So, of course, I got into quite a lot of trouble. It was quite an unpleasant period: the McCarthy period. There were times when my passport was taken away from me and' I couldn't go to scientific meetings abroad, and Caltech was trying to get rid of me (a place I liked very much). I resisted those efforts. But `it wasn't pleasant, so I said that I valued the peace prize more. It showed that working for world peace has'become respectable. * * * * * My thunkr to C.J. Fiscus and Peter Pesavento for their help in the preparation of (his essay. 0140 111 REFERENCES I, 1. Holmes, .Oliver Wendell. 771~ Oxford dicrionnry of quorurions. New York: Oxford Vniversity Press; lY79. p. 253. 2. Peuling L. lhe nuture of the chemical l.wnd a& the swucwe of molecules cd crystals: un infroducfion lo modern srrucfurul chcmisrry. Ithaca, NY: Cornell Univer$ity Press, lY60. 644 p. 9 3. ----------. Citation Classic. Commentary on The nature of the chemical bond and the structure of molecules and crystals: an .introduction to modem structural chemistry. Ithaca, NY: Cornell University Press, 1939. 429 p. Current ContenrsYEngineering, Technology & Applied Sciences 16(4):16, 28 January ,1985 and Current Conrents/Physicai, Chemical & Earth Sciences 25(4): 16, 28 January 1985. 4: Garfield E. In tribute to Linus Paulina: a citation laurcatc. THE SCfENTIST - 3(2):10. 23 January 1989. 5. -------. The new 1945-1954 SC1 cumulation provides unique access to the crucial postwar decade of scientific and technological achievement. Current Confenfs (27):3-10, 4 July 1988. 6. NSF award goes to Linus Pauling. THE SCIENTIST 3(12):17, 12 June 1989. 7. Biography: Linus Pauling. Croat. Chem. Acfn 61:C6-8, 1988. 8. Pauling L. Personal communication. 27 June 1989. 9. --:--------. The nature of the chemical bond. Application of results obtained from the quantum mechanics and from a theory of paramagnetic `susceptibility to the structure of molecules. J. Amer. Chem. Sot. 53:1367-40, 1931. 10. i---.-.. Die Abschirmungskonstanten der relativistischenoder Magnetischcn Rontgenstrahlendubletts (Shielding constants `of relativistic,or magnetic X-ray doublets). Z Phys. 40:344-50, 1926. 11. ----. The shared-electron chemical bond. Proc. Nat. Acad. Sci. USA 14~359-62, 1928. `. 12. ------. Influence of relative ionic sizes'on the properties of ionic compounds. : J. Amer. Chem. Sot. 50:1036-45, 1928. 13. ------------. Application of the quantum mechanics to the structure of the hydrogen molecule and hydrogen molecule ion and to related problems. Chem. Rev. 5:173-213, 1928. 14, _-_----_-. The nature of the chemical bond. II. The one-electron bond and the three- electron bond. J. Amer. Chem. Sot. 53:3225-37, 1931. 15. -----I -_-. Quantum mechanics and the chemical bond. Phys. Rev. 37: 1185-6, 1931. 16. __-- _____. The nature of the chemical bond. III. The transition from one extreme bond type to another. J. Amer. Chem. Sac. 543988-1003, 1932. 17. Pauling L, Itano H A, Singer S J & Wells I C. Sickle cell anemia, a molecular disease. Science llO:543-8, 1949. 18. Pauling L. A molecular theory of general anesthesia. Science 134:15-21, 1961. 19. ---------. The significance of the evidence about ascorbic acid and the common cold. Proc. Nat. Acad. Sci. USA 68:2678-81, 1971. 20. Pauling, Linus (Carl). Eticyclopaedia Btirunnica. Chicago, IL: Encyclopaedia Britannica, 1985. Vol. 9. p. 210-I. 21. Pauling L. The crystal structure of magnesium stannide. J. Amer. Chem. Sot. 4512777-80, 1923. .22. Samson S. Crystal structure of NaCd2. Nature 195:259-62, 1962. 23. Rinkel M, cd. Specific and nonspecijic factors in psychophqnnacology: proceedings cf the `lbird World Congress ofPsychiatry, 4-10 June 1961, Montreal, Canada. New York: Philosophical Library, 1963. 174 p. 24. Pauling L. Apparent icosahedral symmetry is due to directed multiple twinning of cubic crystals. Nature 317:512-4, 1985. 25. Pauling's twinning model. Mosaic 18(4):20-l, Winter 1987-88. 26. Steinhardt P J. `Quasicrystal' investigation is mounting. THE SCIENTIST 3(11):12; 14; 18, 29 May 1989. 27. Papling L. No more war! Westport, CT: Greenwood Press, 1975. 262 p. 28. -----. Letter to editor. (Explanations of cold fusion.) Nature 339(6220): 105, 1 I May 1989. 29. Shoemaker D P, Marsh R E, Ewing F J & rattling L. Interatomic distances and atomic valences in NaZn,,. Acta Crystullogr. 5:637-44, 1952. 30. Bergmnn G, Waugh J L T & Pauling L. Crystal structure of the intermetallic compound Mgss(AI, Zn),s and related phases. Nature 169: 1057-8,. 1952. 31. Pauling, Linus C. (Wasson T, ed.) Nobel Prize winners. New York: Wilson, 1987. p. 798-801. 32. Pauling L. Science and pence: rhe Nobel Peace Prize lecture. Washington, DC: Center for the Study of Democratic Institutions, 1964. I5 p. 10 ,01989 by ISI @ CURRENT CONTENTS@