But for Marie, the emphasis was different: she was clearly enchanted by the physicality of radium as well as its strange new powers; she wanted to see it, to feel it, to put it in chemical combination, to find its atomic weight and its position in the periodic table.
Up to this point the Curies’ work had been essentially chemical, removing calcium, lead, silicon, aluminium, iron, and a dozen rare-earth elements – all the elements other than barium – from the pitchblende. Finally, after a year of this, there came a time when chemical methods alone no longer sufficed. There seemed no chemical way of separating radium from barium, so Marie Curie now began to look for a physical difference between their compounds. It seemed probable that radium would be an alkaline earth element like barium and might therefore follow the trends of the group. Calcium chloride is highly soluble; strontium chloride less so; barium chloride still less so – radium chloride, Marie Curie predicted, would be virtually insoluble. Perhaps one could make use of this to separate the chlorides of barium and radium, using the technique of fractional crystallization. As a warm solution is cooled, the less soluble solute will crystallize out first, and this was a technique which had been pioneered by the rare-earth chemists, striving to separate elements that were chemically almost indistinguishable. It was one that required great patience, for hundreds, even thousands, of fractional crystallizations might be needed, and it was this repetitive and tantalizingly slow process that now caused the months to extend into years.
The Curies had hoped they might isolate radium by 1900, but it was to take nearly four years from the time they announced its probable existence to obtain a pure radium salt, a decigram of radium chloride – less than a ten-millionth part of the original. Fighting against all manner of physical difficulties, fighting the doubts and skepticisms of most of their peers, and sometimes their own hopelessness and exhaustion; fighting (although they did not know it) against the insidious effects of radioactivity on their own bodies, the Curies finally triumphed and obtained a few grains of pure white crystalline radium chloride – enough to calculate radium’s atomic weight (226), and to give it its rightful place, below barium, in the periodic table.
To obtain a decigram of an element from several tons of ore was an achievement with no precedent; never had an element been so hard to obtain. Chemistry alone could not have succeeded in this, nor could spectroscopy alone, for the ore had to be concentrated a thousandfold before the first faint spectral lines of radium could even be seen. It had required a wholly new approach – the use of radioactivity itself – to identify the infinitesimal concentration of radium in its vast mass of surrounding material, and to monitor it as it was slowly, reluctantly, forced into a state of purity.
With this achievement, public interest in the Curies exploded, spreading equally to their magical new element and the romantic, heroic husband-and-wife team who had dedicated themselves so totally to its exploration. In 1903, Marie Curie summarized the work of the previous six years in her doctoral thesis, and in the same year she received (with Pierre Curie and Becquerel) the Nobel Prize in physics.
Her thesis was immediately translated into English and published (by William Crookes in his Chemical News ), and my mother had a copy of this in the form of a little booklet. I loved the minute descriptions of the elaborate chemical processes the Curies performed, the careful, systematic examination of radium’s properties, and especially the sense of intellectual excitement and wonder that seemed to simmer beneath the even-toned scientific prose. It was all down-to-earth, even prosaic – but it was a sort of poetry, too. And I was attracted by the notices on its covers for radium, thorium, polonium, uranium – all of these were freely available, to anyone, for fun or experiment.
There was an advertisement from A.C. Cossor, in Farringdon Road, a few doors from Uncle Tungsten’s place, selling ‘pure radium bromide (when available), pitchblende…Crooke’s high-vacuum tubes, showing the fluorescence of various minerals…[and] other scientific materials.’ Harrington Brothers (in Oliver’s Yard, not far away) sold a variety of radium salts and uranium minerals. J.J. Griffin and Sons (later to become Griffin & Tatlock, where I went for my own chemical supplies) were selling ‘Kunzite – the new mineral, responding in a high degree to the emanations from radium,’ while Armbrecht, Nelson & Co. (a cut above the rest, in Grosvenor Square) had polonium sulphide (in tubes of one gram, twenty-one shillings) and screens of fluorescent willemite (sixpence for a square inch). ‘Our newly invented Thorium inhalers,’ they added, ‘may be had on hire.’ What, I wondered, was a thorium inhaler? Would one feel braced, strengthened, inhaling the radioactive element?
No one seemed to have any idea of the danger of these stuffs at this time.«61» Marie Curie herself mentioned in her thesis how ‘if a radio-active substance is placed in the dark in the vicinity of the closed eye or of the temple, a sensation of light fills the eye,’ and I often tried this myself, using one of the luminous clocks in our house, their figures and hands painted with Uncle Abe’s luminous paint.
I was particularly moved by the description in Eve Curie’s book of how her parents, restless one evening and curious as to how the fractional crystallizations were going, returned to their shed late one night and saw in the darkness a magical glowing everywhere, from all the tubes and vessels and basins containing the radium concentrates, and realized for the first time that their element was spontaneously luminous. The luminosity of phosphorus required the presence of oxygen, but the luminosity of radium arose entirely from within, from its own radioactivity. Marie Curie wrote in lyrical terms of this luminosity:
One of our joys was to go into our workroom at night when we perceived the feebly luminous silhouettes of the bottles and capsules containing our products…It was really a lovely sight and always new to us. The glowing tubes looked like faint fairy lights.
Uncle Abe still had some radium in his possession, left over from his work on luminous paint, and he would show me this, pulling out a vial with a few milligrams of radium bromide – it appeared to be a grain of ordinary salt – at the bottom. He had three little screens painted with platinocyanides – lithium, sodium, and barium platinocyanide – and as he waved the tube of radium (gripped in a pair of tongs) near the darkened screens, these lit up suddenly, becoming sheets of red, then yellow, then green fire, each fading suddenly as he moved the tube away again.
‘Radium has lots of interesting effects on substances around it,’ he said. ‘The photographic effects you know, but radium also browns paper, burns it, pits it, like a colander. Radium decomposes the atoms of the air, and then they recombine in different forms – so you smell ozone and nitrogen peroxide when you are around it. It affects glass – it turns soft glasses blue, and hard glasses brown; it can also color diamonds and turn rock salt a deep, intense violet.’ Uncle Abe showed me a piece of fluorspar which he had exposed to radium for a few days. Its original color had been purple, he said, but now it was pale, charged with strange energy. He heated the fluorspar a little, far below red heat, and it suddenly gave off a brilliant flash, as if it were white-hot, and returned to its original purple.
Another experiment Uncle Abe showed me was to electrify a silk tassel – he did this by stroking it with a piece of rubber – so that its threads, now charged with electricity, repelled one another and flew apart. But as soon as he brought the radium near, the threads collapsed, their electricity discharged. This was because radioactivity made the air conducting, he said, so the tassel could not hold its charge anymore. An extremely refined form of this was the gold-leaf electroscope in his lab – a sturdy jar with a metal rod through its stopper to conduct a charge and two tiny gold foil leaves suspended from this. When the electroscope was charged, the gold leaves would fly apart just like the threads of the tassel. But if one brought a radioactive substance near the jar, it would immediately discharge, and the leaves would drop. The sensitivity of the electroscope to radium was amazing – it could detect a thousand-millionth of a grain, millions of times less
than the amount one could detect chemically, and it was thousands of times more sensitive even than a spectroscope.
I liked to watch Uncle Abe’s radium clock, which was basically a gold-leaf electroscope with a little radium inside, in a separate, thin-walled glass vessel. The radium, emitting negative particles, would gradually get positively charged, and the gold leaves would start to diverge – until they hit the side of the vessel and got discharged; then the cycle would start all over again. This ‘clock’ had been opening and closing its gold leaves, every three minutes, for more than thirty years, and it would go on doing so for a thousand years or more – it was the closest thing, Uncle Abe said, to a perpetual motion machine.
What had been a mild puzzle with uranium had become a much more acute one with the isolation of radium, a million times more radioactive. While uranium could darken a photographic plate (though this took several days) or discharge an ultrasensitive gold-leaf electroscope, radium did this in a fraction of a second; it glowed spontaneously with the fury of its own activity; and, as became increasingly evident in the new century, it could penetrate opaque materials, ozonize the air, tint glass, induce fluorescence, and burn and destroy the living tissues of the body, in a way that could be either therapeutic or destructive.
With radiation of every other sort, going all the way from X-rays to radio waves, energy had to be provided by an external source; but radioactive elements, apparently, had their own power and could emit energy without decrement for months or years, and neither heat nor cold nor pressure nor magnetic fields nor irradiation nor chemical reagents made the least difference to this.
Where did this immense amount of energy come from? The firmest principles in the physical sciences were the principles of conservation – that matter and energy could neither be created nor destroyed. There had never been any serious suggestion that these principles could ever be violated, and yet radium at first appeared to do exactly that – to be a perpetuum mobile, a free lunch, a steady and inexhaustible source of energy.
One escape from this quandary was to suppose that the energy of radioactive substances had an exterior source; this indeed was what Becquerel first suggested, on the analogy of phosphorescence – that radioactive substances absorbed energy from something, from somewhere, and then reemitted it, slowly, in their own way. (He coined the term hyperphosphorescence for this.)
Notions of an outside source – perhaps an X-ray-like radiation bathing the earth – had been entertained briefly by the Curies, and they had sent a sample of a radium concentrate to Hans Geitel and Julius Elster in Germany. Elster and Geitel were close friends (they were known as ‘the Castor and Pollux of physics’), and they were brilliant investigators, who had already shown radioactivity to be unaffected by vacua, cathode rays, or sunlight. When they took the sample down a thousand-foot mine in the Harz Mountains – a place where no X-rays could reach – they found its radioactivity undiminished.
Could radium’s energy be coming from the Ether, that mysterious, immaterial medium that was supposed to fill every nook and cranny of the universe and allow for the propagation of light and gravity and all other forms of cosmic energy? This was Mendeleev’s opinion when he visited the Curies, though given a special chemical twist by him, for he conceived that the Ether was composed of a very light ‘ether element,’ an inert gas able to penetrate all matter without chemical reaction, and with an atomic weight about half that of hydrogen. (This new element, he thought, had already been observed in the solar corona, and named coronium.) Beyond this, Mendeleev conceived of an ultralight etheric element, with an atomic weight less than a billionth that of hydrogen, that permeated the cosmos. Atoms of these etheric elements, he felt, attracted to the heavy atoms of uranium and thorium, and absorbed by them somehow, endowed them with their own etheric energy.«62»
(I was puzzled when I first came across reference to the Ether – often spelled Aether, and capitalized – confusing this with the inflammable, mobile, sharp-smelling liquid my mother kept in her anesthetic bag. A ‘luminiferous’ Ether had been postulated by Newton as the medium in which light waves were propagated, but, as Uncle Abe told me, even in his youth people had already become suspicious of its existence. Maxwell was able to bypass it in his equations, and a famous experiment in the early 1890s had failed to show any ‘Ether drift,’ any effect of the earth’s motion on the velocity of light, such as one might expect if an Ether existed. But clearly the idea of the Ether was still very strong in the minds of many scientists at the time when radioactivity was discovered, and it was natural that they should turn to it first for an explanation of its mysterious energies.«63»
But if it was imaginable – just – that a slow dribble of energy such as uranium emitted might come from an outside source, such a notion became harder to believe when faced with radium, which (as Pierre Curie and Albert Laborde would show, in 1903) was capable of raising its own weight of water from freezing to boiling in an hour.«64» It was harder still when faced with even more intensely radioactive substances, such as pure polonium (a small piece of which would spontaneously become red-hot) or radon, which was 200,000 times more radioactive than radium itself – so radioactive that a pint of it would instantly vaporize any vessel in which it was contained. Such a power to heat was unintelligible with any etheric or cosmic hypothesis.
With no plausible external source of energy, the Curies were forced to return to their original thought that the energy of radium had to have an internal origin, to be an ‘atomic property’ – although a basis for this was hardly imaginable. As early as 1898, Marie Curie added a bolder, even outrageous thought, that radioactivity might come from the disintegration of atoms, that it could be ‘an emission of matter accompanied by a loss of weight of the radioactive substances’ – a hypothesis even more bizarre, it might have seemed, than its alternatives, for it had been axiomatic in science, a fundamental assumption, that atoms were indestructible, immutable, unsplittable – the whole of chemistry and classical physics was built on this faith. In Maxwell’s words:
Though in the course of ages catastrophes have occurred and may yet occur in the heavens, though ancient systems may be dissolved and new systems evolved out of their ruins, the [atoms] out of which these systems are built – the foundation stones of the material universe – remain unbroken and unworn. They continue to this day as they were created – perfect in number and measure and weight.
All scientific tradition, from Democritus to Dalton, from Lucretius to Maxwell, insisted upon this principle, and one can readily understand how, after her first bold thoughts about atomic disintegration, Marie Curie withdrew from the idea, and (using unusually poetic language) ended her thesis on radium by saying, ‘the cause of this spontaneous radiation remains a mystery…a profound and wonderful enigma.’
CHAPTER TWENTY-TWO
Cannery Row
The summer after the war, we went to Switzerland, because this was the only country on the Continent that had not been ravaged by war, and we longed for normality, after six years of bombing and rationing and austerity and constriction. The transformation was evident as soon as we crossed the border – the uniforms of the Swiss customs officers were new and shining, unlike the shabby uniforms on the French side. The train itself seemed to become cleaner and brighter, to move with a new efficiency and speed. Arriving in Lucerne, we were met by an electric brougham. Tall, upright, with huge plate-glass windows, a vehicle such as my parents had seen, but never ridden, in their own childhood, the ancient brougham conveyed us noiselessly to the Schweizerhof Hotel, a hotel vaster, more splendid, than anything I had ever imagined. My parents would generally choose relatively modest lodgings, but this time their instincts led them in the opposite direction, to the most sumptuous, most luxurious, most opulent hotel in Lucerne – an extravagance permitted, they felt, after six years of war.
The Schweizerhof stays in my mind for another reason, because it was here that I gave the first (and last) concert of my life. It had been a li
ttle over a year since Mrs. Silver, my piano teacher, had died, a year in which I had not touched a piano, but now something sunny, something liberating, brought me out, made me want to play again, all of a sudden, and for other people. Though I had been brought up on Bach and Scarlatti, I had grown (under Mrs. Silver’s influence) to love the Romantics – especially Schumann and the propulsive, exuberant Chopin mazurkas. Many of these were technically beyond me, but I knew them, nonetheless, all fifty-odd of them, by heart, and could at least (I flattered myself) give a sense of their feel and vitality. They were miniatures, but each seemed to contain an entire world.
Somehow my parents persuaded the hotel to arrange a concert in its salon, to let me use the grand piano (it was bigger than any I had ever seen, a Bosendorfer with some extra keys our Bechstein did not have), and to announce that, on the coming Thursday night, there would be a recital by ‘the young English pianist Oliver Sacks.’ This terrified me, and I grew more and more nervous as the day approached. But when the evening came, I donned my best suit (it had been made for my bar mitzvah the month before), entered the salon, bowed, arranged my features into a smile, and (almost incontinent with terror) sat down at the piano. After the opening bars of the first mazurka, I got swept away by it, and carried it to a flamboyant conclusion. There was clapping, there were smiles, there was forgiveness of my blunders, so I charged on to the next, and the next, finishing up finally with a posthumous opus (which I vaguely imagined had somehow been completed after Chopin’s death).
There was a special, rare pleasure about this performance. My chemistry and mineralogy and science were all private, shared with my uncles but with nobody else. The recital, in contrast, was open and public, with appreciation, exchange, giving and receiving. It was the opening of something new, the start of an intercourse.