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]
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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.
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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.
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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.