Uncle Tungsten

1

Only one person stayed: Miss Levy, my father’s secretary. She had been with him since 1930, and though somewhat reserved and formal (it would have been unthinkable to call her by her first name; she was always Miss Levy) and always busy, she sometimes allowed me to sit by the gas fire in her little room and play while she typed my father’s letters. (I loved the clack of the typewriter keys, and the little bell that rang at the end of each line.) Miss Levy lived five minutes away (in Shoot-Up Hill, a name that seemed to me more suitable perhaps for Tombstone than Kilburn), and she arrived at nine o’clock on the dot every weekday morning; she was never late, never moody or discomposed, never ill, in all the years that I knew her. Her schedule, her even presence, remained a constant through the war, even though everything else in the house had changed. She seemed impervious to the vicissitudes of life.

Miss Levy, who was a couple of years older than my father, continued to work a fifty-hour week until she was ninety, with no apparent concessions to age. Retirement was unthinkable to her, as it was to my parents, too.

2

There were fears for all the African relatives during the Boer War, and this must have impressed my mother deeply, for more than forty years later, she would still sing or incant a little ditty from this era:

3

There were many attempts to manufacture diamonds in the nineteenth century, the most famous being those of Henri Moissan, the French chemist who first isolated fluorine and invented the electrical furnace. Whether Moissan actually got any diamonds is doubtful – the tiny, hard crystals he took for diamond were probably silicon carbide (which is now called moissanite). The atmosphere of this early diamond-making, with its excitements, its dangers, its wild ambitions, is vividly conveyed in H.G. Wells’s story ‘The Diamond Maker.’

4

The d’Elhuyar brothers, Juan Jose and Fausto, were members of the Basque Society of Friends for Their Country, a society devoted to the cultivation of arts and sciences that would meet every evening, discussing mathematics on Monday evenings, experimenting with electrical machines and air pumps on Tuesday evenings, and so on. In 1777 the brothers were sent abroad, one to study mineralogy, the other metallurgy. Their travels took them all over Europe, and one of them, Juan Jose, visited Scheele in 1782.

After they returned to Spain, the brothers explored the heavy black mineral wolframite and obtained from it a dense yellow powder (‘wolframic acid’) which they realized to be identical to the tungstic acid Scheele had obtained from the mineral ‘tung-sten’ in Sweden, and which, he was convinced, contained a new element. They went ahead, as Scheele had not, to heat this with charcoal, and obtained the pure new metallic element (which they named wolframium) in 1783.

5

Cryolite was the chief mineral in a vast pegmatitic mass in Ivigtut, Greenland, and this ore was mined continuously for more than a century. The miners, who had sailed from Denmark, would sometimes take boulders of the transparent cryolite to use as anchors for their boats, and never quite got used to the way in which these vanished, became invisible, the instant they sank below the surface of the water.

6

In addition to the hundred-odd names of existing elements, there were at least twice that number for elements that never made it, elements imagined or claimed to exist on the basis of unique chemical or spectroscopic characteristics, but later found to be known elements or mixtures. Many were place names, often exotic, discarded because the elements turned out to be spurious: ‘florentium’, ‘moldavium’, ‘norwegium,’ and ‘helvetium’, ‘austrium’ and ‘russium’, ‘illinium’, ‘virginium,’ and ‘alabamine,’ and the splendidly named ‘bohemium.’

I was oddly moved by these fictional elements and their names, especially the starry ones. The most beautiful, to my ears, were ‘aldebaranium’ and ‘cassiopeium’ (Auer’s names for elements that actually existed, ytterbium and lutecium) and ‘denebium,’ for a mythical rare earth. There had been a ‘cosmium’ and ‘neutronium’ (‘element o’), too, to say nothing of ‘archonium’, ‘asterium’, ‘aetherium,’ and the Ur-element ‘anodium,’ from which all the other elements supposedly were built.

There were sometimes competing names for new discoveries. Andres del Rio discovered vanadium in Mexico in 1800 and named it ‘panchromium’ for the variety of its many-colored salts. But other chemists doubted his discovery, and he eventually gave up his claim, and the element was only rediscovered and renamed thirty years later by a Swedish chemist, this time in honor of Vanadis, the Norse goddess of beauty. Other obsolete or discredited names also referred to actual elements: thus the magnificent ‘jargonium,’ an element supposedly present in zircons and zirconium ores, was most probably the real element hafnium.

7

Thomas Mann provides a lovely description of silica gardens in Doctor Faustus:

8

Griffin was not only an educator at many levels – he wrote The Radical Theory in Chemistry and A System of Crystallography, both more technical than his Recreations – but also a manufacturer and purveyor of chemical apparatus: his ‘chemical and philosophical apparatus’ was used throughout Europe. His firm, later to become Griffin & Tatlock, was still a major supplier a century later, when I was a boy.

9

I read John Hersey’s Hiroshima a few years later, and I was struck by this passage:

10

Such thoughts about ‘tuning’, I was later to read, had first been raised in the eighteenth century by the mathematician Euler, who had ascribed the color of objects to their having ‘little particles’ on their surface – atoms – tuned to respond to light of different frequencies. Thus an object would look red because its ‘particles’ were tuned to vibrate, resonate, to the red rays in the light that fell on it:

David Park, in The Fire Within the Eye: A Historical Essay on the Nature and Meaning of Light, writes of Euler’s theory:

11

Now, of course, none of these chemicals can be bought, and even school or museum laboratories are increasingly confined to reagents that are less hazardous – and less fun.

Linus Pauling, in an autobiographical sketch, described how he, too, obtained potassium cyanide (for a killing bottle) from a local druggist:

When I paid a visit not long ago to the old building in Finchley which had been Griffin & Tatlock’s home a half century ago, it was no longer there. Such shops, such suppliers, which had provided chemicals and simple apparatus and unimaginable delights for generations, have now all but vanished.

12

Many years later, when I read Keynes’s wonderful description of Lloyd George (in The Economic Consequences of the Peace), I was strangely reminded of Auntie Lina. Keynes speaks of the British prime minister’s ‘unerring, almost medium-like sensibility to everyone immediately around him.’

13

Hooke himself was to become a marvel of scientific energy and ingenuity, abetted by his mechanical genius and mathematical ability. He kept voluminous, minutely detailed journals and diaries, which provide an incomparable picture not only of his own ceaseless mental activity, but of the whole intellectual atmosphere of seventeenth-century science. In his Micrographia, Hooke illustrated his compound microscope, along with drawings of the intricate, never-before-seen structures of insects and other creatures (including a famous picture of a Brobdingnagian louse, attached to a human hair as thick as a barge pole). He judged the frequency of flies’ wingbeats by their musical pitch. He interpreted fossils, for the first time, as the relics and impressions of extinct animals. He illustrated his designs for a wind gauge, a thermometer, a hygrometer, a barometer. And he showed an intellectual audacity sometimes even greater than Boyle’s, as with his understanding of combustion, which, he said, ‘is made by a substance inherent, and mixt with the Air.’ He identified this with ‘that property in the Air which it loses in the Lungs.’ This notion of a substance present in limited amounts in the air that is required for and gets used up in combustion and respiration is far closer to the concept of a chemically active gas than Boyle’s theory of igneous particles.

Many of Hooke’s ideas were almost completely ignored and forgotten, so that one scholar observed in 1803, ‘I do not know a more unaccountable thing in the history of science than the total oblivion of this theory of Dr. Hooke, so clearly expressed, and so likely to catch attention.’ One reason for this oblivion was the implacable enmity of Newton, who developed such a hatred of Hooke that he would not consent to assume the presidency of the Royal Society while Hooke was still alive, and did all he could to extinguish Hooke’s reputation. But deeper than this is perhaps what Gunther Stent calls ‘prematurity’ in science, that many of Hooke’s ideas (and especially those on combustion) were so radical as to be unassimilable, even unintelligible, in the accepted thinking of his time.

14

In his biography of Lavoisier, Douglas McKie includes an exhaustive list of Lavoisier’s scientific activities which paints a vivid picture of his times, no less than his own remarkable range of mind: ‘Lavoisier took part,’ McKie writes,

15

Boyle had experimented with the burning of metals a hundred years before, and was well aware that these increased in weight when burned, forming a calx or ash that was heavier than the original. But his explanations of the increase of weight were mechanical, not chemical: he saw it as the absorption of ‘particles of fire.’ Similarly, he saw air itself not in chemical terms, but rather as an elastic fluid of a peculiar sort, used in a sort of mechanical ventilation, to wash the impurities out of the lungs. Findings were not consistent in the century that followed Boyle, partly because the gigantic ‘burning glasses’ used were of such power as to cause some metallic oxides to partly vaporize or sublime, causing losses rather than increases in weight. But even more frequently there was no weighing at all, for analytical chemistry, at this point, was still largely qualitative.

16

In this same month, Lavoisier got a letter from Scheele describing the preparation of what Scheele called Fire Air (oxygen) admixed with Fixed Air (carbon dioxide), from heating silver carbonate; Scheele had obtained pure Fire Air from mercuric oxide, even before Priestley had. But in the event, Lavoisier claimed the discovery of oxygen for himself and scarcely acknowledged the discoveries of his predecessors, feeling that they did not realize what it was that they had observed.

All this, and the question of what constitutes ‘discovery,’ is explored in the play Oxygen, by Roald Hoffmann and Carl Djerassi.

17

Replacing the concept of phlogiston with that of oxidation had immediate practical effects. It was now clear, for example, that a burning fuel needed as much air as possible for complete combustion. François-Pierre Argand, a contemporary of Lavoisier’s, was quick to exploit the new theory of combustion, designing a lamp with a flat ribbon wick, bent to fit inside a cylinder, so that air could reach it from both the inside and the outside, and a chimney which produced an updraft. The Argand burner was well established by 1783; there had been no lamp so efficient or so brilliant before.

18

Lavoisier’s list of elements included the three gases he had named (oxygen, azote [nitrogen], and hydrogen), three nonmetals (sulphur, phosphorus, and carbon), and seventeen metals. It also included muriatic, fluoric, and boracic ‘radicals’ and five ‘earths’: chalk, magnesia, baryta, alumina, and silica. These radicals and earths, he divined, were compounds containing new elements, which he thought would soon be obtained (all of them were indeed obtained by 1825, except fluorine, which defeated isolation for another sixty years). His final two ‘elements’ were Light and Heat – as if he had not been wholly able to free himself from the specter of phlogiston.

19

More than fifty years later (for my sixty-fifth birthday), I was able to gratify this boyhood fantasy, and had, besides the normal helium balloons, a few xenon balloons of astonishing density – as near to ‘lead balloons’ as could be (tungsten hexafluoride, though denser, would have been too dangerous to use – it is hydrolyzed by moist air, producing hydrofluoric acid). If one twirled these xenon balloons in one’s hand, then stopped, the heavy gas, by its own momentum, would continue rotating for a minute, almost as if it were a liquid.

20

While Cavendish was the first to observe that hydrogen and oxygen, when exploded together, created water, he interpreted their reaction in terms of phlogiston theory. Lavoisier, hearing of Cavendish’s work, repeated the experiment, reinterpreting the results correctly, and claimed the discovery for himself, making no acknowledgment of Cavendish. Cavendish was unmoved by this, being wholly indifferent to matters of priority and, indeed, to all matters merely human or emotional.

While Boyle and Priestley and Davy were all eminently human and engaging, as well as scientifically brilliant, Cavendish was quite a different figure. The range of his achievements was astounding, from his discovery of hydrogen and his beautiful researches on heat and electricity to his famous (and remarkably accurate) weighing of the earth. No less astounding, and even in his lifetime the stuff of legend, was his virtual isolation (he rarely spoke to anyone, and insisted his servants communicate with him in writing), his indifference to fame and fortune (though he was the grandson of a duke, and for much of his life the richest man in England), and his ingenuousness and incomprehension in regard to all human relationships. I was deeply moved, but if anything more mystified, when I read more about him.

Yet, Wilson continued,

21

The ease of obtaining hydrogen and oxygen by electrolysis, in ideally inflammable proportions, led at once to the invention of the oxy-hydrogen blowpipe, which produced higher temperatures than had ever been obtained before. This allowed, for example, the melting of platinum, and the raising of lime to a temperature at which it gave out the most brilliant sustained light ever seen.

22

Mendeleev, sixty years later, was to speak of Davy’s isolation of sodium and potassium as ‘one of the greatest discoveries in science’ – great in its bringing a new and powerful approach to chemistry, in its defining of the essential qualities of a metal, and in its exhibition of the elements’ twinship and analogy, the implication of a fundamental chemical group.

23

The enormous chemical reactivity of potassium made it a powerful new instrument in isolating other elements. Davy used it himself, only a year after he discovered it, to obtain the element boron from boric acid, and he tried to obtain silicon by the same method (Berzelius succeeded here, in 1824). Aluminium and beryllium, a few years later, were also isolated through the use of potassium.

24

Mary Shelley, as a child, was enthralled by Davy’s inaugural lecture at the Royal Institution, and years later, in Frankenstein, she was to model Professor Waldman’s lecture on chemistry rather closely on some of Davy’s words when, speaking of galvanic electricity, he said, ‘a new influence has been discovered, which has enabled man to produce from combinations of dead matter effects which were formerly occasioned only by animal organs.’

25

David Knight, in his brilliant biography of Davy, speaks of the passionate parallelism, the almost mystical sense of affinity and rapport, that Coleridge and Davy felt, and how the two planned, at one point, to set up a chemical laboratory together. In his book The Friend, Coleridge wrote:

Coleridge was not the only writer to ‘renew his stock of metaphors’ with images from chemistry. The chemical term elective affinities was given an erotic connotation by Goethe; Keats, trained in medicine, reveled in chemical metaphors. Eliot, in ‘Tradition and the Individual Talent,’ employs chemical metaphors, from beginning to end, culminating in a grand, Davyan metaphor for the poet’s mind: ‘The analogy is that of the catalyst… The mind of the poet is the shred of platinum.’

26

The great chemist Justus von Liebig wrote powerfully about this feeling in his autobiography:

The faculty of thinking in phenomena can only be cultivated if the mind is constantly trained, and this was effected in my case by my endeavouring to perform, so far as my means would allow me, all the experiments whose description I read in the books… I repeated such experiments… a countless number of times,… till I knew thoroughly every aspect of the phenomenon which presented itself… a memory of the sense, that is to say of the sight, a clear perception of the resemblance or differences of things or of phenomena, which afterwards stood me in good stead.

27

Davy went on with his investigations of flame, and, a year after the safety lamp, published Some Philosophical Researches on Flame. More than forty years later, Faraday would return to the subject, in his famous Royal Institution lectures on The Chemical History of a Candle.

28

Enlarging on Davy’s observation of catalysis, Dobereiner found in 1822 that platinum, if finely divided, would not only become white-hot, but would ignite a stream of hydrogen passing over it. On this basis he made a lamp consisting basically of a tightly sealed bottle containing a piece of zinc which could be lowered into sulphuric acid, generating hydrogen. When the stopcock of the bottle was opened, hydrogen gushed out into a small container holding a bit of platinum sponge, and instantly burst into flame (a slightly dangerous flame, because it was virtually invisible, and one had to be cautious to avoid being burned). Within five years, there were twenty thousand Dobereiner lamps in use in Germany and England, so Davy had the satisfaction of seeing catalysis at work, indispensable in thousands of homes.

29

I was intrigued, too (though I never practiced it), by cine-photography. Here again it was Walter who made me realize that there was no actual movement in the film, only a succession of still images which the brain synthesized to give an impression of movement. He demonstrated this to me with his film projector, slowing it down to show me only the still images, and then speeding it up until the illusion of motion suddenly occurred. He had a zoetrope, with images painted on the inside of a wheel, and a thaumatrope, with drawings on a stack of cards, which when rotated, or rapidly flicked, would give the same illusion. So I had the sense that movement, too, was constructed by the brain, in a manner analogous to that of color and depth.

30

Wells’s reference to the Martians’ unknown element also intrigued me later when I learned about spectra, for he described it, early in the book, as ‘giving a group of four lines in the blue of the spectrum,’ though subsequently – did he reread what he had written? – as giving ‘a brilliant group of three lines in the green.’

31

Yet Proust’s view was challenged by Claude-Louis Berthollet. A senior chemist of great eminence, an ardent supporter of Lavoisier (and a collaborator with him on the Nomenclature), Berthollet had discovered chemical bleaching and accompanied Napoleon as a scientist on his 1798 expedition to Egypt. He had observed that various alloys and glasses manifestly had quite varied chemical compositions; therefore, he maintained, compounds could have a continuously variable composition. He also remarked, when roasting lead in his laboratory, a striking, continuous color change – did this not imply a continuous absorption of oxygen with an infinite number of stages? It was true, Proust argued, that heated lead took up oxygen continuously and changed color as it did so, but this was due, he thought, to the formation of three distinctly colored oxides: a yellow monoxide, then red lead, then a chocolate-colored dioxide – admixed like paints, in varying proportions, depending on the state of oxidation. The oxides themselves might be mixed together in any proportion, he felt, but each was itself of fixed composition.

Berthollet also wondered about such compounds as ferrous sulphide, which never contained exactly the same proportions of iron and sulphur. Proust was unable to give a clear answer here (and indeed the answer only became clear with a subsequent understanding of crystal lattices and their defects and substitutions – thus sulphur can substitute for iron in the iron sulphide lattice to a variable extent, so that its effective formula varies from Fe₇ S₈ to Fe₈ S₉. Such nonstoichiometric compounds came to be called berthollides).

Thus both Proust and Berthollet were right in a way, but the vast majority of compounds were Proustian, with a fixed composition. (And it was perhaps necessary that Proust’s view became the favored one, for it was Proust’s law which was to inspire the profound insights of Dalton.)

32

Though Newton hinted, in his final Quaerie, at something that almost seems to prefigure a Daltonian concept:

33

Dalton represented the atoms of elements as circles with internal designs, sometimes reminiscent of the symbols of alchemy, or the planets; while the compound atoms (which we would now call ‘molecules’) had increasingly intricate geometric configurations – the first premonition of a structural chemistry that was not to be developed for another fifty years.

Though Dalton spoke of his atomic ‘hypothesis,’ he was convinced that atoms really existed – hence his violent objection to the terminology Berzelius was to introduce, in which an element was denoted by one or two letters of its name rather than his own iconic symbol. Dalton’s passionate opposition to Berzelius’s symbolism (which he felt concealed the actuality of atoms) lasted to the end of his life, and indeed when he died in 1844 it was from a sudden apoplexy, following a violent argument defending the realness of his atoms.

34

These names for metallic trees came from the alchemical notion of the correspondence between the sun, the moon, and the five (known) planets with the seven metals of antiquity. Thus gold stood for the sun, silver for the moon (and the moon goddess, Diana), mercury for Mercury, copper for Venus, iron for Mars, tin for Jupiter Qove), and lead for Saturn.

35

A discovery that for some reason especially interested me was Faraday’s discovery of diamagnetism in 1845. He had been experimenting with a very powerful new electromagnet, placing various transparent substances between its poles to see whether polarized light could be affected by the magnet. It could, and Faraday now found that the very heavy lead glass that he had used for some experiments actually moved when the magnet was switched on, aligning itself at right angles to the magnetic field (this was the first time he used the term field). Prior to this all known magnetic substances – iron, nickel, magnetite, etc. – had aligned themselves along the magnetic field, rather than at right angles to it. Intrigued, Faraday went on to test the magnetic susceptibility of everything he could lay his hands on – not only metals and minerals, but glass, flames, meat, and fruit, too.

When I spoke of this to Uncle Abe, he allowed me to experiment with the very powerful electromagnet he had in his attic, and I was able to duplicate a lot of Faraday’s findings, and to find, as he had, that the diamagnetic effect was especially powerful with bismuth, which was strongly repelled by both poles of the magnet. It was fascinating to see how a thin shard of bismuth (as near a needle as I could get with the brittle metal) aligned itself, almost violently, perpendicular to the magnetic field. I wondered whether, if it was sufficiently delicately poised, one might make a bismuth compass that pointed east-west. I experimented with bits of meat and fish, and wondered about experimenting with living creatures, too. Faraday himself had written, ‘If a man could be in the magnetic field, like Mahomet’s coffin he would turn until across the magnetic field.’ I wondered about putting a small frog, or perhaps an insect, in the field of Uncle Abe’s magnet, but feared this might freeze the motion of its blood, or blow its nervous system, turn out to be a refined form of murder. (I need not have worried: frogs have now been suspended for minutes in magnetic fields, and are apparently none the worse for the experience. With the vast magnets now available, an entire regiment could be suspended.)

36

He was distracted, too, creatively, by a dozen competing interests and commitments during this time: the investigation of steels, the making of special highly refractive optical glasses, the liquefaction of gases (which he was the first to achieve), the discovery of benzene, his many chemical and other lectures at the Royal Institution, and the publication in 1827 of his Chemical Manipulations.

37

Having no higher mathematics myself, unlike Uncle Abe, I found much of Maxwell’s work inaccessible, whereas I could at least read Faraday and feel I was getting the essential ideas, despite the fact that he never used mathematical formulas. Maxwell, expressing his indebtedness to Faraday, spoke of how his ideas, though fundamental, could be expressed in nonmathematical form:

It was perhaps for the advantage of science that Faraday, though thoroughly conscious of the fundamental forms of space, was not a professed mathematician… and did not feel called upon… to force his results into a shape acceptable to the mathematical taste of the time… He was thus left at leisure to do his proper work, to coordinate his ideas with the facts, and to express them in natural untechnical language…[Yet, Maxwell continued] As I proceeded with the study of Faraday I perceived that his method of conceiving the phenomena was also a mathematical one, though not exhibited in the conventional form of mathematical symbols.

38

Sir Ronald Storrs, the British governor of Jerusalem at the time, described his first encounter with Annie in his 1937 memoir, Orientations:

39

‘The compound forming the incense,’ the Talmud prescribed in almost stoichiometric terms,

40

Years later, when I read C.P. Snow, I found that his reaction to first seeing the periodic table was very similar to mine:

41

In his very first footnote, in the preface, Mendeleev spoke of ‘how contented, free, and joyous is life in the realm of science’ – and one could see, in every sentence, how true this was for him. The Principles grew like a living thing in Mendeleev’s lifetime, each edition larger, fuller, more mature than its predecessors, each filled with exuberating and spreading footnotes (footnotes which became so enormous that in the last editions they filled more pages than the text; indeed, some occupied nine-tenths of the page – I think my own love of footnotes, the excursions they allow, was partly determined by reading the Principles).

42

Mendeleev was not the first to see some significance in the atomic weights of elements. When the atomic weights of the alkaline earth metals were established by Berzelius, Dobereiner was struck by the fact that the atomic weight of strontium was just midway between that of calcium and barium. Was this an accident, as Berzelius thought, or an indication of something important and general? Berzelius himself had just discovered selenium in 1817, and at once realized that (in terms of chemical properties) it ‘belonged’ between sulphur and tellurium. Dobereiner went further, and brought out a quantitative relationship too, for its atomic weight was just midway between theirs. And when lithium was discovered later that year (also in Berzelius’s kitchen lab), Dobereiner observed that it completed another triad, of alkali metals: lithium, sodium, and potassium. Feeling, moreover, that the gap in atomic weight between chlorine and iodine was too great, Dobereiner thought (as Davy had before him) that there must be a third element analogous to them, a halogen, with an atomic weight midway between theirs. (This element, bromine, was discovered a few years later.)

There were mixed reactions to Dobereiner’s ‘triads,’ with their implication of a correlation between atomic weight and chemical character. Berzelius and Davy were doubtful of the significance of such ‘numerology,’ as they saw it; but others were intrigued and wondered whether an obscure but fundamental significance was lurking in Dobereiner’s figures.

43

This, at least, is the accepted myth, and one that was later promulgated by Mendeleev himself, somewhat as Kekule was to describe his own discovery of the benzene ring years later, as the result of a dream of snakes biting their own tails. But if one looks at the actual table that Mendeleev sketched, one can see that it is full of transpositions, crossings-out, and calculations in the margins. It shows, in the most graphic way, the creative struggle for understanding which was going on in his mind. Mendeleev did not wake from his dream with all the answers in place, but, more interestingly, perhaps, woke with a sense of revelation, so that within hours he was able to solve many of the questions that had occupied him for years.

44

In an 1889 footnote – even his lectures had footnotes, at least in their printed versions – he added: ‘I foresee some more new elements, but not with the same certitude as before.’ Mendeleev was well aware of the gap between bismuth (with an atomic weight of 209) and thorium (232), and conceived that several elements must exist to fill it. He was most certain of the element immediately following bismuth – ’an element analogous to tellurium, which we may call dvi-tellurium.’ This element, polonium, was discovered by the Curies in 1898, and when finally isolated it had almost all the properties Mendeleev had predicted. (In 1899 Mendeleev visited the Curies in Paris and welcomed radium as his ‘eka-barium.’)

In the final edition of the Principles, Mendeleev made many other predictions – including two heavier analogs of manganese – an ‘eka-manganese’ with an atomic weight of around 99, and a ‘tri-manganese’ with an atomic weight of 188; sadly, he never saw these. ‘Tri-manganese’ – rhenium – was not discovered until 1925, the last of the naturally occurring elements to be found; while ‘eka-manganese,’ technetium, was the first new element to be artificially made, in 1937.

He also envisaged, by analogy, some elements following uranium.

45

It is a remarkable example of synchronicity that in the decade following the Karlsruhe conference there emerged not one but six such classifications, all completely independent of one another: de Chancourtois’s in France, Odling’s and Newlands’s, both in England, Lothar Meyer’s in Germany, Hinrichs’s in America, and finally Mendeleev’s in Russia, all pointing toward a periodic law.

De Chancourtois, a French mineralogist, was the first to devise such a classification, and in 1862 – just eighteen months after Karlsruhe – he inscribed the symbols of twenty-four elements spiraling around a vertical cylinder at heights proportional to their atomic weights, so that elements with similar properties fell one beneath another. Tellurium occupied the midpoint of the helix; hence he called it a ‘telluric screw,’ a vis tellurique. But the Comptes Rendu, when they came to publish his paper, managed – grotesquely – to omit the crucial illustration, and this, among other problems, put paid to the whole enterprise, causing de Chancourtois’s ideas to be ignored.

Newlands, in England, was scarcely any luckier. He, too, arranged the known elements by increasing atomic weight, and seeing that every eighth element, apparently, was analogous to the first, he proposed a ‘Law of Octaves,’ saying that ‘the eighth element, starting from a given one, is a kind of repetition of the first, like the 8th note in an octave of music.’ (Had the inert gases been known at the time, it would, of course, have been every ninth element that resembled the first.) A too-literal comparison to music, and the suggestion even that these octaves might be a sort of ‘cosmic music,’ evoked a sarcastic response at the meeting of the Chemical Society at which Newlands presented his theory; it was said that he might have done as well to arrange the elements alphabetically.

There is no doubt that Newlands, even more than de Chancourtois, was very close to a periodic law. Like Mendeleev, Newlands had the courage to invert the order of certain elements when their atomic weight did not match what seemed to be their proper position in his table (though he failed to make any predictions of unknown elements, as Mendeleev did).

Lothar Meyer was also at the Karlsruhe conference and was one of the first to use the revised atomic weights published there in a periodic classification. In 1868 he came up with an elaborate sixteen-columned periodic table (but the publication of this was delayed until after Mendeleev’s table had appeared). Lothar Meyer paid special attention to the physical properties of the elements and their relation to atomic weights, and in 1870 he published a famous graph plotting the atomic weights of the known elements against their ‘atomic volumes’ (this being the ratio of atomic weight to density), a graph that showed high points for the alkali metals and low points for the dense, small-atomed metals of Group VIII (the platinum and iron metals), with all the other elements falling nicely in between. This graph proved a most potent argument for a periodic law and did much to assist the acceptance of Mendeleev’s work.

But at the time of discovering his ‘Natural System,’ Mendeleev was either ignorant of, or denied knowledge of, any attempts comparable to his own. Later, when his name and fame were established, he became more knowledgeable, perhaps more generous, less threatened by the notion of any codiscoverers or forerunners. When, in 1889, he was invited to give the Faraday Lecture in London, he paid a measured tribute to those who had come before him.

46

Cavendish, however, sparking the nitrogen and oxygen of air together, had observed in 1785 that a small amount (‘not more than 1⁄120th part of the whole’) was totally resistant to combination, but no one paid any attention to this until the 1890^s.

47

I think I identified at times with the inert gases, and at other times anthropomorphized them, imagining them lonely, cut off, yearning to bond. Was bonding, bonding with other elements, absolutely impossible for them? Might not fluorine, the most active, the most outrageous of the halogens – so eager to combine that it had defeated efforts to isolate it for more than a century – might not fluorine, if given a chance, at least bond with xenon, the heaviest of the inert gases? I pored over tables of physical constants and decided that such a combination was just, in principle, possible.

In the early 1960^s, I was overjoyed to hear (even though my mind at this time had moved on to other things) that the American chemist Neil Bartlett had managed to prepare such a compound – a triple compound of platinum, fluorine, and xenon. Xenon fluorides and xenon oxides were subsequently made.

Freeman Dyson has written to me describing his boyhood love of the periodic table and of the inert gases – he, too, saw them, in their bottles, in the Science Museum in South Kensington – and how excited he was years later when he was shown a specimen of barium xenate, seeing the elusive, unreactive gas firmly and beautifully locked up in a crystal:

48

A spectacular anomaly came up with the hydrides of the nonmetals – an ugly bunch, about as inimical to life as one could get. Arsenic and antimony hydrides were very poisonous and smelly; silicon and phosphorus hydrides were spontane ously inflammable. I had made in my lab the hydrides of sulphur (H₂ S), selenium (H₂ Se), and tellurium (H₂ Te), all Group VI elements, all dangerous and vile-smelling gases. The hydride of oxygen, the first Group VI element, one might predict by analogy, would be a foul-smelling, poisonous, inflammable gas, too, condensing to a nasty liquid around – 100°C. And instead it was water, H₂ O – stable, potable, odorless, benign, and with a host of special, indeed unique properties (its expansion when frozen, its great heat capacity, its capacity as an ionizing solvent, etc.) which made it indispensable to our watery planet, indispensable to life itself. What made it such an anomaly? Water’s properties did not undermine for me the placement of oxygen in the periodic table, but made me intensely curious as to why it was so different from its analogs. (This question, I found, had only been resolved recently, in the 1930^s, with Linus Pauling’s delineation of the hydrogen bond.)

49

Ida Tacke Noddack was one of a team of German scientists who found element 75, rhenium, in 1925-26. Noddack also claimed to have found element 43, which she called masurium. But this claim could not be supported, and she was discredited. In 1934, when Fermi shot neutrons at uranium and thought he had made element 93, Noddack suggested that he was wrong, that he had in fact split the atom. But since she had been discredited with element 43, no one paid any attention to her. Had she been listened to, Germany would probably have had the atomic bomb and the history of the world would have been different. (This story was told by Glenn Seaborg when he was presenting his recollections at a conference in November 1997.)

50

Although elements 93 and 94, neptunium and plutonium, were created in 1940, their existence was not made public until after the war. They were given provisional names, when they were first made, of ‘extremium’ and ‘ultimium,’ because it was thought impossible that any heavier elements would ever be made. Elements 95 and 96, however, were created in 1944. Their discovery was not made public in the usual way – in a letter to Nature, or at a meeting of the Chemical Society – but during a children’s radio quiz show in November 1945, during which a twelve-year-old boy asked, ‘Mr. Seaborg, have you made any more elements lately?’

51

Auguste Comte had written, in his 1835 Cours de la Philosophie Positive:

52

Uncle Abe told me something of the history of matches, how the first matches had to be dipped into sulphuric acid to light them before ‘lucifers’ – friction matches – were introduced in the 1830^s, and how this led to a huge demand for white phosphorus over the next century. He told me of the awful conditions under which match girls worked in the factories and of the terrible disease, ‘phossy-jaw,’ they often got, until the use of white phosphorus was banned in 1906. (Only red phosphorus, far more stable, and far safer, was subsequently used.)

Abe also spoke of the hellish phosphorus bombs used in the Great War, and how there was a move to ban these, as poison gas had been banned. But now, in 1943, they were being used freely once again, and thousands of people on both sides were being burned alive in the most agonizing way possible.

53

Phosphorus, oxidizing slowly, was not the only element to glow when exposed to air. Sodium and potassium did this too, when they were freshly cut, but lost their luminosity in a few minutes as the cut surfaces tarnished. I found this by chance as I was working in my lab late one afternoon, as it gradually darkened into dusk – I had not yet switched on the light.

54

Equally important were cathode-ray tubes, which were now being developed for television. Abe himself had one of the original television sets of the 1930^s, a huge, bulky thing with a tiny circular screen. Its tube, he said, was not much different from the cathode-ray tubes that Crookes had developed in the 1870^s, except that its face was coated with a suitable phosphor.

Cathode-ray tubes in use for medical or electronic apparatus were often coated with zinc silicate, willemite, which emitted a brilliant green light when bombarded, but for television one needed phosphors that would give a clear, white light – and if color television was to be developed, one would need three separate phosphors with exactly the right balance of color emissions, like the three pigments in color photography. The old dopants used in luminous paints were quite unsuitable for this; much more delicate and precise colors were needed.

55

Uncle Abe also showed me other types of cold light. One could take various crystals – like uranyl nitrate crystals, or even ordinary cane sugar – and crush them, with a mortar and pestle, or between two test tubes (or even one’s teeth), cracking the crystals against one another – this would cause them to glow. This phenomenon, called triboluminescence, was recognized even in the eighteenth century, when Father Giambattista Beccaria recorded:

Even crystallization could cause luminescence; Abe suggested that I make a saturated solution of strontium bromate and then let it cool slowly in the dark – at first nothing happened, and then I began to see scintillations, little flashes of light, as jagged crystals formed on the bottom of the flask.

56

The same phenomenon, I read, had been used ingeniously to make self-luminous buoys – these were encircled by rings of strong glass tubing containing mercury under reduced pressure, which would be swirled against the glass and electrified by the motion of the waves.

57

Shoe shops everywhere in my boyhood were equipped with X-ray machines, fluoroscopes, so that one could see how the bones of one’s feet were fitting in new shoes. I loved these machines, for one could wiggle one’s toes and see the many separate bones in the foot moving in unison, in their almost transparent envelope of flesh.

58

Dentists were especially at risk, holding small X-ray films inside their patients’ mouths, often for minutes at a time, for the original emulsions were very slow. Many dentists lost fingers by exposing their hands to X-rays in this way.

59

Henri Becquerel’s grandfather, Antoine Edmond Becquerel, had launched the systematic study of phosphorescence in the 1830^s and published the first pictures of phosphorescent spectra. Antoine’s son, Alexandre-Edmond, had assisted in his father’s research and invented a ‘phosphoroscope,’ which allowed him to measure fluorescences that lasted as briefly as a thousandth of a second. His 1867 book, Lumiere, was the first comprehensive treatment of phosphorescence and fluorescence to appear (and the only one for the next fifty years).

60

In 1998 I spoke at a meeting for the centennial of the discovery of polonium and radium. I said that I had been given this book when I was ten, and that it was my favorite biography. As I was talking I became conscious of a very old lady in the audience, with high Slavic cheekbones and a smile going from one ear to the other. I thought, ‘It can’t be!’ But it was – it was Eve Curie, and she signed her book for me sixty years after it was published, fifty-five years after I got it.

61

Becquerel had been the first to note the injury that might result from radioactivity – he discovered a burn on himself after carrying a highly radioactive concentrate in his waistcoat pocket. Pierre Curie explored the matter, allowing a deliberate radium burn on his arm. Yet he and Marie never fully faced the dangers of radium, their ‘child.’ Their laboratory, it was said, glowed in the dark, and both, perhaps, were to die from its effects. (Pierre, weakened, died in a traffic accident; Marie, thirty years later, from an aplastic anemia.) Radioactive specimens were sent freely in the post, and handled with little protection. Frederick Soddy, who worked with Rutherford, believed that handling radioactive materials had made him sterile.

And yet there was ambivalence, for radioactivity was also seen as benign, as healing. Besides thorium inhalers, there was thorium toothpaste, made by the Auer Company (Auntie Annie used to keep her dentures overnight in a glass with ‘radium sticks’), and the Radioendocrinator, containing radium and thorium, to be worn around the neck to stimulate the thyroid or around the scrotum to stimulate the libido. People went to spas to take the radium water.

The most serious problem arose in the United States, where doctors prescribed the drinking of radioactive solutions such as Radithor as rejuvenating agents, as well as to cure stomach cancer or mental illness. Thousands of people drank such potions, and it was only the highly publicized death in 1932 of Eben Byers, a prominent steel magnate and socialite, that put an end to the radium craze. After consuming a daily radium tonic for four years, Byers developed severe radiation sickness and cancer of the jaw; and he died grotesquely as his bones disintegrated, like Monsieur Valdemar in the Edgar Allan Poe story.

62

Retaining his flexibility of mind to the last, Mendeleev renounced his Etheric hypothesis the year before he died, and acknowledged his acceptance of the ‘unthinkable’ – transmutation – as the source of radioactive energy.

63

The Ether was pressed into many other uses, too. For Oliver Lodge, writing in 1924, it was still the needed medium for electromagnetic waves and gravitation, even though the theory of relativity, by this time, was widely known. It was also, for Lodge, the medium that provided a continuum, a matrix in which discrete particles, atoms and electrons, could be embedded. Finally, for him (as for J.J. Thomson and many others), the Ether took on a religious or metaphysical role, too – it became the medium, the realm, where spirits and Mind-at-large dwelled, where the life force of the dead maintained a sort of quasi-existence (and could perhaps be summoned forth by the efforts of mediums). Thomson and many other physicists of his generation became active members, founders, of the British Psychical Society, a reaction, perhaps, against the materialism of the time and the perceived or imagined death of God.

64

After reading about this, I wondered whether any radioactive substances actually felt warm to the touch. I had small bars of uranium and thorium, but they felt as cool as any other metal bars. I once held Uncle Abe’s little tube, with its ten milligrams of radium bromide, in my hand, but the radium was no bigger than a grain of salt, and I felt no warmth through the glass.

I was fascinated to learn from Jeremy Bernstein that he once held a sphere of plutonium in his hands – the core of an atomic bomb, no less – and found it uncannily warm to the touch.

65

Marie Curie’s own laboratory notebooks, a century later, are still considered too dangerous to handle and are kept in lead-lined boxes.

66

Soddy envisaged this artificial transmutation fifteen years before Rutherford achieved it, and imagined explosive or controlled atomic disintegrations long before fission or fusion were discovered.

67

It was reading The World Set Free in the 1930^s that set Leo Szilard to thinking of chain reactions and getting a secret patent on these in 1936; in 1940 he persuaded Einstein to send his famous letter to Roosevelt about the possibilities of an atomic bomb.

68

By 1914, the scientists of Britain and France and Germany and Austria were all caught up, in various ways, in the First World War. Pure chemistry and physics were largely suspended for the duration, and applied science, war science, took its place. Rutherford ceased his fundamental research, and his lab was reorganized for work on submarine detection. Geiger and Marsden, who had observed the alpha-particle deflections that gave rise to Rutherford’s atom, found themselves at the Western Front, on different sides. Chadwick and Ellis, younger colleagues of Rutherford’s, were prisoners of war in Germany. And Moseley, aged twenty-eight, was killed by a bullet in the brain, at Gallipoli. My father often used to talk of the young poets, the intellectuals, the cream of a generation wiped out tragically in the Great War. Most of the names he mentioned were unknown to me, but Moseley’s was the one I knew, and the one I mourned most.

69

This gave Bohr predictive power too. Moseley had observed that element 72 was missing, but could not say whether it would be a rare-earth element or not (elements 57-71 were rare earths, and 73, tantalum, was a transition element, but no one was sure how many rare earths there would be). Bohr, with his clear idea of the numbers of electrons in each shell, was able to predict that element 72 would not be a rare-earth element, but a heavier analog of zirconium. He suggested that his colleagues in Denmark seek this new element in zirconium ores, and it was swiftly found (and named hafnium, after the old name for Copenhagen). This was the first time the existence and properties of an element were predicted not by chemical analogy, but on the purely theoretical basis of its electronic structure.

70

It was also wondered, early in the twentieth century, what might happen to the ‘electron gas’ in metals if they were cooled to temperatures near absolute zero – would this ‘freeze’ all the electrons, turning the metal into a complete insulator? What was found, using mercury, was the complete opposite: the mercury became a perfect conductor, a superconductor, suddenly losing all its resistance at 4.2 degrees above absolute zero. Thus one could have a ring of mercury, cooled by liquid helium, with an electrical current flowing around it with no diminution, for days, forever.

71

The universe started, Gamow conceived, as almost infinitely dense – perhaps no larger than a fist. Gamow and his student Ralph Alpher went on to suggest (in a famous 1948 article that came to be known, after Hans Bethe was invited to add his name, as the alpha-beta-gamma paper), that this primal fist-sized universe exploded, inaugurating space and time, and that in this explosion (which Hoyle, derisively, was to call the Big Bang) all of the elements were created.

But here he was wrong; it was only the lightest elements – hydrogen and helium and perhaps a little lithium – that originated in the Big Bang. It was not until the 1950^s that it became clear how the heavier elements were generated. It might take billions of years for an average star to consume all its hydrogen, but the more massive stars, far from extinguishing at this point, could contract, becoming hotter still, and start on further nuclear reactions, fusing their helium to produce carbon, fusing this in turn to produce oxygen, and then silicon, phosphorus, sulphur, sodium, magnesium – all the way up to iron. Beyond iron no energy could be released by further fusion, so this accumulated as an end point in nucleosynthesis. Hence its remarkable abundance in the universe, an abundance reflected in metallic meteorites and in the iron core of the earth. (The heavier elements, those beyond iron, remained a puzzle for longer; they only originate, apparently, with supernova explosions.)

72

This question again resonated for me when I read Primo Levi’s wonderful book The Periodic Table, especially the chapter called ‘Potassium.’ Here Levi speaks of his own search, as a student, for ‘sources of certainty.’ Deciding he would become a physicist, Levi left the chemistry lab and apprenticed himself to the physics department – to an astrophysicist, in particular. This did not work out quite as he had hoped, for while some ultimate certainties might indeed be found in stellar physics, such certainties, though sublime, were abstract and remote from daily life. More soul-filling, nearer life, were the beauties of practical chemistry. ‘When I understand what’s going on inside a retort,’ Levi once remarked, ‘I’m happier. I’ve extended my knowledge a little bit more. I haven’t understood truth or reality. I’ve just reconstructed a segment, a little segment of the world. That’s already a big victory inside a factory laboratory.’

73

I was not quite alone. A most important guide to me at this point was George Gamow, a scientist-writer of great versatility and charm whose Birth and Death of the Sun I had already read. In his ‘Mr. Tompkins’ books (Mr. Tompkins in Wonderland and Mr. Tompkins Explores the Atom, published in 1945), Gamow uses the device of altering physical constants by many orders of magnitude to make otherwise unimaginable worlds at least half-imaginable. Relativity is made comically imaginable by supposing the velocity of light to be only thirty miles per hour, and quantum mechanics equally so by imagining Planck’s constant increased by twenty-eight orders of magnitude, so that one can have quantum effects in ‘real’ life – thus quantum tigers, smeared out in a quantum jungle, are nowhere and everywhere at once.

I sometimes wondered whether any ‘macroquantal’ phenomena existed, whether one might ever be able to see, under extraordinary conditions, a quantal world with one’s own eyes. One of the unforgettable experiences of my life was exactly this, when I was introduced to liquid helium, and saw how this changed its properties suddenly at a critical temperature, turning from a normal liquid into a strange superfluid with no viscosity, no entropy whatever, able to go through walls, to climb out of a beaker, and with a thermal conductivity three million times that of normal liquid helium. This impossible state of matter could only be understood in terms of quantum mechanics: the atoms were now so close together that their wave functions overlapped and merged, so that one had, in effect, a single giant atom.

74

I wish I had realized – but that would not have been easy for me as a boy – that Crookes was wrong, that the new insight about the atom which prompted his thoughts (he was writing this in 1915, just two years after Bohr) would serve, once assimilated, to expand and enrich chemistry enormously, not to reduce it, annihilate it, as he feared. There were similar anxieties about the first atomic theory: many chemists, Humphry Davy among them, felt there was danger in accepting Dalton’s notions of atoms and atomic weights, danger of pulling chemistry away from its concreteness and reality into an arid, impoverished, metaphysical realm.