ll. t. Ch . 22 ( 8
THE 1996 DEXTER AWARD ADDRESS CONTRASTS IN CHEMICAL STYLE: SIDGWICK AND EYRING
K th . dl r, Un v r t f Ott
In th ddr I ll th n b t t p pl I d r n th p r d th t h l t r d n h tr . nt nt t th rl n r r, v l n nt h Y n ( 82 nd n th r , p rt S d nd nr E r n . h ff r tr n n l rl n b r f h t , l b n th r r r n tr t n v r r p t, nd th ntr t b t n th th pr t f d n . S v r l nt t , l W ll ll tr t th n f h h I h v b r nd Gr v ( 8 8 6 nd ph l t ( 80 88 , r nv n d I h v r d n th h t r f b l r b f r b n nt t Gr v , n n th t th r r ll n h th n nt f f t, f n ll nt b nt l nd b j d . th d. h r r n f d n d S v r l nt t h v n h r t r n n n n th r r d nt t . M r v r, n n f ld th r th n n th t th r b tt r n n f r d l ttl pl nn n h d n th f p f n th r th r h v nt th n f r th r nt f r . t f r r h n t n t ntl d n An bv x pl th r h t t S r Chr t ph r t d l n pr d th th r . Wr n ( 6 2 2 , h th t n nd pr t f n r l nt f r t, b f r f tr n t Oxf rd h r l th ph f r I t S d nd E r n . n nt t , nd t nd t t n nj n r n l n ( 06 0 nd nd d nt t , ft n th n th t nt t r th p r Al x nd r r d n ( 8 88 , h n p l br d f p pl . I h v b n f ll t pr f r f h tr f r th t p rt h l n h t n p r n ll n d r bl n nl p d h n h d d n t f l ll n h t d b r f nt t , n f th xtr l d n , nt f r t b t n t l t, th r Ch nd I h v r d n b r ph f nt t . M n W z nn ( 8 4 2 , h b th f r t r d nt l n th t nt t r h th th r f th St t f I r l, nd h ld pr b bl n t h v p t nt p pl nd th t th r r n r d ff r b n h n f r th t p t n f h h d n t d n , n r t n b t n d ff r nt nt t , v n b t n th n, v r p rt nt r r h n h tr h h r n n th f ld. ntr b t d t th ll d n W rld W r I. r n th n , n d nt t ld h v S nt t , th n, t b v r h l th r b n f l n n th n th nd rt t d . Q t p pl h r nt r t d n nt ll t l p r t . In th r n b r f nt t d d n t r n ll nt nd t b n r l b h v r l , nt t j t l th r nt t . . h n ( 8 6 40 , . A. M. r p pl . S r n r , nd th pr p rt n f n ( 02 84 , nd nr E r n , f r x pl , r n ll r nt t n t bv l d ff r nt fr th pr nt d t b n n r t h rd t b l v th t th p rt n f n r p pl h l . A f nt t ld n t h v b n d n . ph l ( 28 h v b n ndr l , b t n th r pr p rt n t d l d r nd pr t d d n n r t r th n th t n th n r l p p l t n l 2 Bull. Hist. Chem. 22 (1998) belief does not seem to be much affected by whether plications without going into all the details; he then col- one is a scientist or not. Michael Faraday (1791-1865) lated a huge mass of experimental data on the basis of was a Sandemanian, which means that he was a reli- his interpretation of the theories. Eyring worked the other gious fundamentalist; one wonders, incidentally, how way round; he arrived at his ideas intuitively, then for- he would have taken to the theory of evolution. Henry mulated his theories on the basis of rigorous mathemati- Eyring was born a Mormon and rose to high office in cal treatments, and finally examined the way in which that church. Some scientists, including Sidgwick, were his formulations fitted the experimental results. agnostics; but their proportion seems about the same as that among other intellectuals. Nevil Vincent Sidgwick Some scientists are highly gregarious, some are Perhaps I may tell a personal story about how I first hermits, and most are somewhere in between. Most sci- came in touch with Sidgwick (1, 2; Fig. 1). While at entists are enthusiastic about discussing their ideas with school in England in the early thirties I decided that I others, but some fear that their ideas will be stolen by wanted to be a chemist; and since the man who taught others and are secretive. Wilhelm Konrad von me chemistry was an Oxford man he thought that Ox- Röntgen(1845-1923), famous for his discovery of X- ford was the best university for me. The system at Ox- rays, is believed never to have discussed his scientific work with anyone. Oliver Heaviside (1850-1925), re- membered today for the Heaviside layer in the iono- sphere, retired at the age of 24 (perhaps a record for early retirement) and tried to avoid speaking to anyone during the rest of his life. Now I come to the two men I am going to talk about, Sidgwick and Eyring. First I will say something about the differences in their personalities. Sidgwick was aus- tere in manner and never married, while Eyring was friendly and gregarious, and loved his wife and family. Sidgwick was by no means easy to talk to, while Eyring was just the opposite. Sidgwick was an avowed atheist, while Eyring was a devout Mormon. What they did have in common was a devotion to science and a high regard for the truth. Both had a great effect on the progress of chemistry. Chemists today who may not know much about their work are greatly influenced by what Sidgwick and Eyring did, since it is reflected in the textbooks we use today. The two men contrasted sharply in their ways of doing science. Sidgwick had little competence in math- ematics and made little use of it in his work. All of Eyring's work, on the other hand, was of a mathemati- cal character. Sidgwick was a great scholar of science, by which I mean that he studied the scientific literature Figure I. v l n nt S d ( 8 2 , fr ph t r ph v n b S d t th th r with great care, and was thoroughly familiar with the n th 40 , p rh p d r n W rld W r I h d experimental results that had been obtained in all l d h th f r v r l d d . branches of chemistry. Eyring, on the other hand, did not pay too much attention to what had been done be- fore; he preferred to think about science in an intuitive ford is that one must first gain admission to a college, way and seemed to pick up experimental facts (or get which automatically makes one a member of the Uni- his graduate students to pick them up) as he needed them versity. I again took the advice of my teacher. The out- to test his theoretical ideas. Sidgwick based his work on standing chemist at Oxford, he said, was Sidgwick, who mathematical treatments that had been worked out by at Lincoln College; and in fact at school I had al- others, and he had the knack of understanding their im- ready read his famous Electronic Theory of Valency Bull. Hist. Chem. 22 (1998) 3
(Clarendon Press, Oxford, 1929). He added that there Brodie, who was Aldrichian professor of chemistry at was also a younger man who was showing great prom- Oxford from 1855 to 1872. The Archbishop must have ise - a man called Hinshelwood at Trinity College. I been a little discomfited by the fact that Brodie, Henry therefore put Lincoln College down as my first choice Sidgwick, N. V. Sidgwick's father, and Sidgwick himself and Trinity as my second. were all fairly militant atheists. In December, 1933 I took the scholarship Sidgwick was a student at Christ Church, Oxford, examination, and I still remember very vividly that when where his tutor was A. G. Vernon Harcourt (1834-1919), I was doing the experimental part of the examination one of the early pioneers in chemical kinetics. He gained Hinshelwood came beside me, and in his unforgettable first-class honors in natural science in 1895 but found drawl said, "Well, Laidler, how are you getting on?" I that his rather classically minded relatives considered a made some mumbling reply, now forgotten. A few days degree in science to be much inferior to one in classics. later I learned that I had been accepted by Hinshelwood, Just to impress them he stayed on in Oxford for two and as a result I went to Trinity College. There is an more years and then gained first-class honors in Greats, amusing sequel to this story, which I learned about only which covers classical literature and philosophy in the recently. I was in correspondence with Professor Brebis original languages, Latin and Greek. Bleaney, who became professor of experimental Sidgwick later went to Tübingen University, philosophy at Oxford in 1956 and has done distinguished studying under von Pechmann, and in 1901 was awarded work in electron spin resonance spectroscopy. It turned a D. Sc. degree summa cum laude, for work in organic out that he, too, had given Lincoln College as his first chemistry. He was elected to a tutorial fellowship at choice at exactly the same time. We had both sat the Lincoln College, Oxford, and from 1901 the College same examination and had therefore been rivals, but he, was his home until he died in 1952; he never married. too, had been turned down by Sidgwick and had been From 1901 to 1916 he carried out research, mainly on chosen by H. W. Thompson, the spectroscopist, for St. the physical properties of organic compounds, but did John's College. Thompson,incidentally, had been one little work of any distinction until he was in his late of Hinshelwood's students and had perhaps learned from forties. This late development in a scientist is unusual Hinshelwood the art of snatching people away from but not unique. Sir William Bragg (1862-1942) was also Sidgwick. well in his forties before he did anything much in science, I still clearly remember, although it was over 60 and then, with much help from his son Lawrence Bragg years ago, sitting in front of Sidgwick at his lectures. (1890-1971), he pioneered X-ray crystallography. This was at the time when he was working on his massive In 1916 Sidgwick moved to the new organic two-volume Chemical Elements and their Compounds chemistry laboratories, which were directed by Sir (Clarendon Press, Oxford, 1950). When that book later William Henry Perkin, Jr. (1860-1929). The two could came out, in 1950, I realized that my lecture notes taken scarcely tolerate each other. Sidgwick had a deep interest fifteen years before were very much like a precis of the in physical chemistry, which Perkin thought a waste of book. The lectures were quite superb; meticulously time; Sidgwick claimed that Perkin on several occasions prepared, they were delivered with great style. At the said to him "Physical chemistry is all very well, but of end of each lecture he picked up his notes and walked course it doesn't apply to organic compounds." Since out; in those days and in that University there was no recorded organic compounds constitute over 99 per cent opportunity for anyone to ask a lecturer a question. This of the total number of chemical compounds, this was sounds unsatisfactory, but we had tutors whom we saw hardly an enthusiastic endorsement of physical for at least an hour once a week. Since my tutor was chemistry. Hinshelwood, who also was a great chemical scholar as Sidgwick's later successes followed a suggestion well as a man of great originality, I did not feel deprived in 1914 from Ernest Rutherford (1871-1937) that he as far as getting help was concerned. should relate chemical properties to the new electronic Nevil Vincent Sidgwick was born in Oxford in and quantum theories, something that had never been 1873, of a rather remarkable family. His father had been done before. Just a year previously Niels Bohr (1885- a teacher of classics at Oxford and later a lecturer in 1962) had published his famous work on which he politics and political economy. His uncles included explained the orbital arrangements of electrons in atoms, Henry Sidgwick, professor of moral philosophy at work that he had carried out in Rutherford's laboratories Cambridge, Edward White Benson, who later became in Manchester. At once Sidgwick began to consider how Archbishop of Canterbury, and Sir Benjamin Collins chemical properties could be explained on the basis of
4 Bull. Hist. Chem. 22 (1998) these ideas. In 1916 G. N. Lewis (1875-1946) published inviting him to stay at their fraternity, Telluride House, his famous paper on his octet theory and in subsequent which he greatly appreciated and enjoyed. From then years developed his ideas in many ways. Irving on he crossed the Atlantic whenever he could, becoming Langmuir (1881-1957) also made important one of the best known British scientists in the United contributions in this field, and since he was an excellent States; in the end he was proud to have visited 46 of the lecturer he did much to make chemists aware of these 48 continental states. (I myself, incidentally, have visited important new developments. all 48 of them; the last one I got to, rather surprisingly, In 1919 Sidgwick applied for the Dr. Lee's was Maine). Professorship at Oxford, but the appointment went On Sidgwick's return from his first visit to Cornell, instead to Frederick Soddy (1877-1965), who was to in 1932, his energies were mainly devoted to expanding receive the 1921 Nobel Prize for Chemistry. The choice, and applying in much greater detail his previous though understandable at the time, turned out to be a formulation of the electronic theory. He labored for about poor one, as Sidgwick's teaching and later research twenty years on his great book, The Chemical Elements would have made him a much better professor than and their Compounds; when it appeared in 1950 he was Soddy, who did little research and gave indifferent seventy-seven. It consisted of two massive volumes lectures during his tenure of the chair. In 1922, when containing a total of about 750,000 words. It was written Sidgwick was forty-nine, he was elected a Fellow of the in a lively style and gave an astonishing and panoramic Royal Society, and in 1924 he was appointed University Reader in Chemistry. The title of Professor was conferred on him in 1935. Sidgwick did not do anything highly original, but he followed the work of Lewis and Langmuir; his important contribution was to use it to explain chemical behavior. His detailed knowledge of the facts of chemistry put him into a unique position to apply the electronic theories to a wide range of chemical compounds. His work led to his book The Electronic Theory of Valency which appeared in 1927, when he was fifty-four. The book was soon recognized to be a scientific classic. In it Sidgwick skillfully and lucidly gave a fresh unity to the whole of chemistry, which for the most part had been presented as a large collection of isolated facts. This book had a wide influence. At once the textbooks of chemistry, even those used in high schools, began to change; even if they did not mention Sidgwick by name, they were influenced by his ideas. In 1931 there came a great change in Sidgwick's life and attitude toward others. He was invited by Cornell University to be the George Fisher Baker Lecturer in Chemistry. This was to be his first visit to the United Figure 2. A ph t r ph t n n 0 f S d n States, and with a prejudice that was rather typical of th ph l h tr t h n l b r t r t ll l him he announced that he was 'sure he would not like nd r n t C ll , Oxf rd. the place.' Within a week of his arrival, however, he had completely reversed his opinion, afterwards taking every view of much of chemistry as it was at the time. This opportunity to return. On his first visit he was fifty-eight, book also quickly became a classic. It is nt r t n , and a formidable figure, quite set in his ways. Oxford rather unusual, that Sidgwick's reputation is based students had always been in awe of him, but the Cornell almost entirely on his books, and scarcely on his papers students saw him quite differently and were able to in research journals. penetrate the crusty exterior, finding an amusing and In appearance and personality Sidgwick was kindly man underneath. They even called him `Gran'pa,' unusual. Figure 2 shows him as he was in 1910, and he which delighted him. They paid him the compliment of looks rather elderly. At the time, however, he was only
Bull. Hist. Chem. 22 (1998) 5
thirty-seven. When I first saw him twenty-four years later present at a seminar that Eyring had given at Oxford in he looked almost exactly the same; only the depth of his 1937, a seminar that is still deeply engraved in my mind, collars had decreased. Indeed, forty years after that because afterwards F. A. Lindemann (later Lord picture was taken he still looked much the same. He Cherwell), the professor of physics, was publicly ex- was always conventional in dress and invariably carried tremely rude to an umbrella; even in the hot California sun he would Eyring, treating wear a felt hat, a thick English suit, and a raincoat. He him like a stupid cared very little about his surroundings, and his rooms schoolboy who in Lincoln College always looked shabby and untidy. had forgotten his In his relationships with others he was very basic physics. I prejudiced, either completely approving or completely remember that disapproving; in Leslie Sutton's rd (2 : afterwards Hinshelwood In p r n l j d nt h d t t b rr d b th p t t f n t v xtr l d n r t n. n r t nd nn b He would aggressively pounce on any loose or inaccu- h v r. I also re- rate statement and so made a few enemies; others be- member th t came immune to being bitten. He made a particular point n ft r I t of being rude to clergymen. He was quite prepared to E r n h r adjust his prejudices if confronted with adequate evi- f rr d t h t dence as he did after his first visit to the United States. nd nn h d In 1951, in failing health, h d t r n d t d, h h h make what he knew must be his last v t t the United h d n t r ll States. After undergoing an operation he returned to Figure 3. nr E r n ( 0 f nd v r f 8 , fr ph t r ph v n b where the students Telluride House at C rn ll Un v r t , f n v . E r n t th th r n th 0 . helped him to go up and down t r nd took him for n h l d trips to see the autumn colors. He had a stroke on the t d t th t I h ld p t E r n d n ship returning to England and spent h f n l nth n nd h . Wh n I nt rv d f r th nursing home, where he died peacefully on March 15, f ll h p th h r n f th tt t ld th t 1952. Throughout his adult life he insisted that he had they had decided that I f l, b t nt n d no belief in God or in an after life. th t n En l h n d r n th p t f r h d n t r t th C l f rn In t t t f hn l Henry Eyring th l n ld I nd n n t d t r n t n I mentioned earlier that when I became an undergradu- t r th E r n , nd h . W ld I nd? ate, my first choice had been to go to Sidgwick's col- Of r I v rj d. h , t nd r l lege (Lincoln), but that instead I became Hinshelwood's t n l f I v n nd h n t d pupil at Trinity. A similar thing happened when I be- f f r t, nd I n th n th t th f rt n t f r came a graduate student in 1938. Late in 1937 I applied . If I h d b n r nt d f r t h , S d for a fellowship which would allow me to go to an nd l n , b nt r r ld pr b bl h v American university, asking Hinshelwood for advice. b n v r d ff r nt. In t d f r n n n t , I Hinshelwood was always in favor of broadening one's h ld p rh p h v n ntr t d n h l tr t r , nd I h v f l n th t I ht ll h v b n experience. Since I th n d n a year's undergradu- ate research in kinetics with him, his idea was that I pl t f l r t t. I should do my graduate work in another branch of chem- nt n th t n d nt f b n v n istry. His advice was that I should give Linus Pauling nd h t ph z th t h r l d pl (1901-1994) as my first choice, and this I did. I also had r t r l n ll r l v . I h v ft n p l t d t to give a second choice. My research with Hinshelwood h t ld h v h pp n d t M h l r d , th n had brought us into contact with what Henry Eyring had f n p v r h d bl th l v n n th l f been doing at Princeton, particularly his formulation of nd n, f h h d n t t j b th ndl b b nd r transition-state theory in 1935.1 had in fact myself been h n r d h t r d th b h b nd, r f
6 Bull. Hist. Chem. 22 (1998) kindly customer had not given him a ticket to go and when Mathews, after inspecting the job, said that it was hear one of Sir Humphry Davy's lectures. Faraday might perhaps good enough for a first coat. Eyring later well have lived in obscurity; at least he might have remarked to a colleague that the department would never started his career much later. Similarly, what if Joseph amount to anything as long as it was run in the way it Henry (1797-1878), living near Albany, New York, had was. That remark got back to Mathews, and within an not chased his pet rabbit under the village library, from hour Eyring was fired. In those days, of course, one could there finding his way into the library, and into the world not grieve — or rather, if one did, one did it alone. of books? Would he ever have become a distinguished In 1929-30 Eyring spent a year in Berlin scientist? collaborating with Michael Polanyi on the construction Shakespeare, as always, had something wise and of the first potential-energy surface for a chemical interesting to say about that sort of thing (3): reaction. In 1931 he was appointed professor of chemistry at Princeton. He had discovered to his surprise There is a tide in the affairs of men, that he was officially a Mexican citizen and became a Which, taken at the flood, leads on to fortune; naturalized American citizen in 1935. In 1946 he went Omitted, all the voyage of their life Is bound in shallows and in miseries. to the University of Utah as Dean of Graduate Studies and professor of chemistry, remaining there until the end I never made a fortune, but have been fortunate in my of his life. career, having been washed along by the tide, avoiding When I arrived at Princeton to work with him in by sheer luck the shallows and miseries that a career 1938 he had three years earlier made what was perhaps sometimes leads to. his most important contribution to science, the I worked with Henry Eyring (4-8; Figure 3) from formulation of transition-state theory. The theory was 1938 to 1940. He was born in 1901 in Colonia Juarez, still highly controversial, and his main interest at the Mexico, of American parents. time was to apply it to problems After studying mining other than gas reactions. My work engineering at the University with him was first on reactions on of Arizona, he went to the surfaces, about which I knew a University of California at fair amount because of my work Berkeley, obtaining a Ph. D. with Hinshelwood. We devised a degree in physical chemistry way of dealing with the partition under George Gibson in 1927. functions of surfaces and of He taught for a period at the surface layers and were able to University of Wisconsin (9) show that the theory is quite and always enjoyed telling that satisfactory in interpreting the he had been fired from the rates of surface reactions. We also chemistry department there, as looked at a number of reactions a result of a disagreement with in solution, and they seemed to the chairman, J. Howard fit in also. After I had been at Mathews (1881-1970). From Princeton for a year Samuel all accounts Mathews was a Glasstone (Fig. 4), then in his difficult man with rigid and old early forties, came over from fashioned ideas, and it is easy England and joined Eyring's to see how he and Eyring could research team. Glasstone was never have agreed. Eyring was already well known for a number required to conduct a Figure 4. Samuel Glasstone (1897-1986), from a of very lucid books he had photograph given by Glasstone to the author in the laboratory course, and written on physical chemistry. (I Mathews first ordered him to 1960s. After a distinguished career in physical chemistry, with several books to his credit, still refer to them from time to paint the floor, which even in Glasstone became a nuclear engineer, working at time, as they are excellent on the those days was an unusual the Los Alamos Scientific Laboratory until 1969 basic concepts of assignment for a member of the and then for the U. S. Atomic Energy Commission thermodynamics, statistical academic staff. Eyring at Oak Ridge, Tennessee. He received several mechanics, X-ray scattering, complied, and was not pleased awards for his work on nuclear engineering and and so forth.) Glasstone also had published books in that field also. Bull. Hist. Chem. 22 (1998)
made a name for himself in electrochemistry and had that had perhaps just occurred to him but which did not worked on overvoltage. Overvoltage was still something have much to do with the subject of his lecture. But his of a mystery, and Eyring, Glasstone, and I worked on graduate classes at Princeton consisted of only a handful the application of transition-state theory to it, with very of students, and he did not mind at all if we interrupted successful results. At the same time, the three of us him with a comment like, "Henry, we've no idea what decided that the time was ripe for a book on transition you are talking about;" he would grin cheerfully and state theory. Eyring, never much of a writer, left the get back to his subject. In the end we all learned a very actual writing to Glasstone and me; but he contributed great deal from him. It had been realized, however, that enormously to it by his lengthy discussions of the subject he would be poor at teaching undergraduates, and I matter and his penetrating criticisms of what we had believe he never did so. written. I remember very vividly one of the—always very S n nd t t r friendly— arguments we had. Glasstone and I were on In expressing my great appreciation for receiving the one side, Henry Eyring on the other. We broke off for Dexter Award, I should emphasize again the enormous lunch, and Glasstone and I had ours together. As we role that good luck has played in my career. I got a won- continued our discussion, we decided that Henry was derful start by having C. N. Hinshelwood (10-12; Fig. right after all. When the three of us met again, we admitted to Eyring that h was right, but were rather taken aback when he told us that he had decided that we were right. The argument than continued, but with the opposing parties reversed, and soon we saw the funny side of it, and could not continue for laughing. Unfortunately, after so long, I cannot remember exactly what sides we were taking at the various times, although I do remember that it was a rather subtle point about the temperature-dependence of an equilibrium constant expressed with respect to concentrations rather than pressures. Needless to say, that problem is now one with which I have no difficulty; having an argument like that, with people like that, does straighten out one's thinking. Our book, h h r f t r (McGraw- Hill, New York), came out in 1941. Three of the chapters in it, on electrode processes, reactions on surfaces, and reactions in solution, comprised essentially my Ph. D. dissertation, submitted in the spring of 1940. I remember that after I took my oral examination, the examiners remained closeted together for such a long time that I felt sure that I had failed. When they came out and I was told that I had passed, I asked Henry why there was such a delay. "Oh," he said, "they weren't arguing about you; r . C r l r n n h l d ( 8 they were arguing about absolute rate theory" (as 6 , fr ph t r ph t n b th th r transition-state theory was then called.) n 6 . Éyring had a friendly disposition and was always happy to discuss his scientific work with anyone who 5) as my tutor while I was an undergraduate, and I am would listen. He was always full of ideas, many of them sure I derived my interest in the history of science from wrong, but he always welcomed criticism; and his him. Hinshelwood's work has in some quarters been un- suggestions could always be turned into sound scientific derrated, and I should like to say a few words about treatments. In a formal sense, Eyring was not a good that. In the 1920s and 1930s Hinshelwood did some very university lecturer. I have mentioned that Sidgwick was original work on explosions in gases and on reactions always well organized, but Eyring was just the opposite. on surfaces and in solution. This work, in my opinion, He tended to go off on tangents, talking about something was worthy of a Nobel Prize. His Nobel Prize, however,
• 8 Bull. Hist. Chem. 22 (1998)
was not awarded to him until 1956, and by that time his the conclusion that we today would expect. History must work was of much less originality. Also, he had not kept describe what happened, not what we think ought to h v up well with the latest advances. This was largely be- happened. I am sure that I derived my initial interest in cause he had many other responsibilities, such as run- writing about science and its history from Hinshelwood's ning a large physical chemistry laboratory. When he won influence. I also learned much about scientific writing the Nobel Prize there was some criticism, because many as a result of my association with Samuel Glasstone in people were only aware of his later work. I think, how- writing The Theory of Rate Processes. I feel remarkably ever, that if we consider his achievements as a whole fortunate to have been so closely associated with those and the influence he had on the growth of physical chem- two remarkable men. istry, the award was fully justified. In particular I learned from both Hinshelwood and Like Sidgwick, Hinshelwood was very much a Glasstone the most important precepts about writing, scholar in the field of chemistry, and he knew the subject which were stated by Sir Peter Medawar and which I through and through. I saw him for an hour or so every slightly modify as follows: week for three years during term time, and we covered C rr tn , n , nd l r t , th thr : every aspect of chemistry. I remember doing with him t th r t t f th l r t . such specialized topics as the organic chemistry of the Let me end with a brief comment anthocyanins. Hinshelwood on these three characteristics. had a deep knowledge of the Correctness, of course, speaks for history of science, and itself; we must get everything naturally a lot of that rubbed off right. There is much more to the on me. I had to write an essay truth than that, however; we can for him every week on some put forward perfectly correct in- chemical subject, chosen by formation but end up with noth- him, and then read it to him. ing but a big lie. That great histo- Today this ancient custom rian Lord Macaulay made a very seems old-fashioned and shrewd comment about this. He amateurish, but I assure you was concerned with the matter of that it was effective. He listened selecting the appropriate material attentively, and any error of when one is writing history, and fact, syntax, or grammar was wrote(13): politely but firmly pointed out h d f nt n th rt f at the end; naturally one strove l t n , b h n n th to make these criticisms n b t th tr th, pr d ll th unnecessary by very carefully ff t f th r t t f l h d. checking what one had written. I still remember vividly, This is part of what is meant by although it was sixty years ago, the word cogency: we must select reading to him an essay on the our material in such a way that the reader is left with a correct impres- decomposition of hydrocarbons Figure 6. K th dl r (b. 6 , fr and mentioning the work of W. ph t r ph t n n 4 , th r f p bl t n sion of the truth. A. Bone, who was then active f h h r f t r . h t r ph b Finally, in writing about science in the field. I wrote that Bone K r h f Ott . the greatest of the virtues is clar- had obtained certain results, ity. It will be obvious that clarity which he had interpreted in terms of a free-radical is important, but we should be aware of some curi- mechanism. For once Hinshelwood broke his rule of not ous problems that may arise. Let me tell a little story, a interrupting, and exclaimed, "What! Old Bone! Old true one. In my early days of teaching I was once told Bone doesn't believe in free radicals." That short by a student that the students in my class understood statement taught me two important lessons on writing my lectures very well. Then she spoiled everything by the history of science. First, check your references adding, "None of us can understand Professor X at all; properly, and second, do not assume that a scientist drew but then, he is very brilliant." For a few seconds I was a Bull. Hist. Chem. 22 (1998) 9 little taken aback. Here was I, working hard to make my . . W. Urr , Int. J. Quantum Chem., Quantum Biology lectures clear, only to be regarded by the students as Symposium, 82, 9, . half-witted. I soon recovered and have continued to try 6. K. . dl r nd M. C. K n , . Phys. Chem., 8 , 87, to express myself as clearly as possible; but I am puzzled, 26 2664. and also a little concerned, by the fact that quite a few , K. J. dl r, Dictionary of Scientific Biography, Supple- ment, 0, 2 284. people seem to think that a person who speaks or writes 8. W. K z nn, Biogr. Mem. Natl. Acad. Sci. USA, 6, obscurely must be very clever, something I know to be 70, I . untrue. There are several books about science for the . A. . Ihd , Chemistry as Viewed from Bascom's Hill: A general public which I think are written very obscurely, History of the Chemistry Department at the University which have nevertheless sold well. Do some members of Wisconsin in Madison, Ch tr p rt nt, U. of the public say to themselves, "I can't understand a W n n, M d n, WI, 0 th f r n f E r n word of this book, so it must be a good one, and the v r d n p. 0 . author very clever?" The truth is that there is no corre- 0. E. . n, Chem. Br., 6 , 3, 4 6. lation between obscurity and brilliance. . . W. h p n, Biogr. Mem. Fellows R. Soc., , 19, There is a great need for the public to know more 4 . 2. K. . dl r, Archive for the History of Exact Sciences, about science, since science and its technical 88, 38, . consequences enter so much into our lives. Writing about . . . M l , History of England, n n, Gr n the history of science is one of the best ways of informing nd C ., nd n, 84 , pr f . the public, and there is room for much more to be done. ABOUT THE AUTHOR REFERENCES AND NOTES Keith J. Laidler (Fig. 6), winner of the 1996 Dexter . S r . z rd, Biogr. Mem. Fellows R. Soc., 4, , 2 Award for Excellence in the History of Chemistry, is 2 8. Professor Emeritus of Chemistry at the University of 2. . E. S tt n, Proc. Chem. Soc. London, , 0 . Ottawa, Ottawa, Ontario K1N 6N5. Aside from his work . W ll Sh p r , Julius Caesar, A t 4, S n . on the history of science, he has carried out theoretical 4. S. . th, " nr É r n : M r n S nt t," M.S. h , p rt nt f t r , Un v r t f Ut h, 80 and experimental investigations on various aspects of p bl h d n nd n d f r n J. Chem. Educ., 8 , chemical kinetics and has published several scientific 62, 8. books.