Uncle Tungsten

by Oliver Sacks

  Edison’s vision, Uncle liked to say, of light for the masses, had finally come true in the incandescent bulb. If someone could look at the earth from outer space, see how it rotated every twenty-four hours into the shadow of night, they would see millions, hundreds of millions, of incandescent bulbs light up nightly, glowing with white-hot tungsten, in the folds of that shadow – and know that man had finally conquered the darkness. The incandescent bulb had done more to alter social habits, human lives, Uncle would say, than any other invention he could think of.

  And in many ways, Uncle Dave told me, the history of chemical discovery was inseparable from the quest for light. Before 1800, one had only candles or simple oil lamps such as had been used for thousands of years. Their light was feeble, and the streets were dark and dangerous, so one could hardly go out at night without a lantern or a full moon. There was a tremendous need for an efficient form of lighting that could be used safely and easily in the home and in streetlamps.

  At the beginning of the nineteenth century gas lighting was introduced, and people experimented with many forms of this. Different nozzles produced gas flames of different shapes: there was the bat’s-wing and the fish-tail and the cock-spur and the cock’s-comb – I loved these names, as he said them, just as I loved the beautiful shapes of the flames.

  But gas flames, with their glowing carbon particles, were scarcely brighter than candle flames. One needed something additional, a material that would shine with special brilliance when heated in a gas flame. Such a substance was calcia – calcium oxide, or lime – which shone with an intense greenish white light when heated. This ‘limelight,’ Uncle Dave said, was discovered in the 1820s and used to illuminate the stages in theaters for many decades – that was why we still talked about ‘the limelight,’ even though we no longer used lime for incandescence. One could get a similar brilliant light by heating several other earths – zirconia, thoria, magnesia, alumina, zinc oxide. (‘Do they call that zincia?’ I asked. ‘No,’ said Uncle, smiling – ’I never heard it called that.’)

  It became clear by the 1870s, after many oxides had been tried, that there were some mixtures that glowed more brilliantly than any of the individual oxides. Auer von Welsbach, in Germany, experimented with innumerable such combinations and finally, in 1891, hit on the ideal: a 99-to-l mixture of thoria and ceria.This ratio was critical: a 100-to-l or 98-to-l ratio, Auer found, was far less effective.

  Up to this point, bars or pencils of oxide had been used, but Auer found that ‘a fabric of suitable shape,’ a ramie mantle, could provide a far greater surface area to be impregnated with his mixture and thus a brighter light. These mantles would revolutionize the whole industry of gas lighting, allowing it to seriously compete with the infant electric light industry.

  My Uncle Abe, a few years older than Uncle Dave, had a vivid memory of this discovery, and of how their somewhat dimly lit house in Leman Street was suddenly transformed by the new incandescent mantles. He remembered too how there had been a great thorium rush: in the course of a few weeks thorium rose to ten times its previous price and a desperate search began for new sources of the element.

  Edison, in America, was also a pioneer experimenter on the incandescence of various rare earths, but had failed to make the breakthrough that Auer did, and had turned his attention in the late 1870s to perfecting a different sort of light, an electric light. Swan, in England, and several others, had started experimenting with platinum bulbs in the 1860s (Uncle had one of these early Swan bulbs in his cabinet); and Edison, intensely competitive, now joined the race, but found, like Swan, that there were major difficulties: platinum’s melting point, though high, was not high enough.

  Edison experimented with many other metals with higher melting points to get a workable filament, but none proved suitable. Then in 1879 he had a brainwave. Carbon had a much higher melting point than any metal – no one had ever been able to melt it – and though it conducted electricity, it had a high resistance, which would make it heat up and incandesce more easily. Edison tried making spirals of elemental carbon, akin to the metal spirals in earlier filaments, but these carbon spirals fell apart. His solution – almost absurdly simple, though it took an act of genius on his part to see it – was to take an organic fiber (paper, wood, bamboo, linen or cotton thread) and burn it, leaving a skeleton of carbon sufficiently strong to hold together and conduct a current. If these filaments were inserted into evacuated bulbs, they could provide a steady light for hundreds of hours.

  Edison’s bulbs opened up the possibility of a real revolution – though, of course, they had to be tied to a whole new system of dynamos and power lines. ‘The first central electrical system in the world was constructed by Edison right here in 1882,’ Uncle said, taking me to the window and motioning toward the streets below. ‘Big steam dynamos were installed on Holborn Viaduct, over there, and they supplied three thousand electric lightbulbs along the Viaduct, and on Farringdon Bridge Road.’

  The 1880s, then, were dominated by electric bulbs and the setting up of a whole network of power stations and power lines. But then in 1891, Auer’s perfected gas mantles, which were highly efficient and moderately priced (and could use existing gas lines), mounted a serious challenge to the young industry of electric light. My uncles had told me about the fight between electric and gas lighting when they were young, and how the balance kept shifting in favor of one or the other. Many houses built in this era – including ours – had been equipped for both, as it was unclear which would win out in the end. (Even fifty years later, in my boyhood, there were many streets in London, especially in the City, that were still lit by gas mantles, and sometimes at dusk one could see the lamplighter with his tall pole, going from one streetlamp to another, lighting them one by one. I loved to watch this.)

  But for all their virtues, the carbon bulbs had problems. They were fragile and became more so with use, and they could only be run at a relatively low temperature, so one had a dullish yellow light, not a brilliant white one.

  Was there any way out of this? One needed a material with a melting point almost as high as carbon’s, or at least around 3,000°C, but with a toughness a thread of carbon could never have – and only three such metals were known: osmium, tantalum, and tungsten. Uncle Dave seemed to become more animated at this point. He admired Edison and his ingenuity enormously, but carbon filaments, it was obvious, were not to his taste. A respectable filament, he seemed to feel, had to be made of metal, for only metals could be drawn to form proper wires. A wire of soot, he sniffed, was a contradiction in terms, and it was astounding that they held up as well as they did.

  The first osmium bulbs were made in 1897 by Auer, and Uncle Dave had one of these in his cabinet. But osmium was very rare – the total world production was only fifteen pounds a year – and very costly. It was almost impossible then to draw osmium into wire, so the osmium powder had to be mixed with a binder and squirted into a mold, the binder being subsequently burned off. These osmium filaments, moreover, were very fragile and would break if the bulbs were turned upside down.

  Tantalum had been known for a century or more, though there had always been great difficulties in purifying and working it. By 1905 it became possible to purify the metal enough to draw it into wires, and with tantalum filaments, incandescent bulbs could be mass-produced cheaply and compete with carbon bulbs in a way never possible with osmium bulbs. But to get the requisite resistance, one had to use a great length of spidery-thin wire, zigzagging it inside the bulb to make a complex cagelike filament. Though tantalum softened a little when heated, these filaments were nonetheless highly successful, and finally challenged the hegemony of the gas mantle. ‘Suddenly,’ Uncle said, ‘tantalum bulbs were all the rage.’

  Tantalum bulbs continued to be the rage until the First World War, but even at the height of their popularity, another filament metal, tungsten, was being explored. The first viable tungsten lamps were made in 1911, and could operate briefly at very high temperatures, t
hough they would soon blacken with the evaporation of tungsten and its deposition on the inner surface of the glass. This challenged the ingenuity of Irving Langmuir, an American chemist who suggested the use of an unreactive gas to exert a positive pressure on the filament, and thus reduce its evaporation. An absolutely inert gas was called for, and an obvious candidate was argon, which had been isolated fifteen years before. But the use of gas filling in turn led to another problem: massive heat loss from convection through the gas. The answer to this, Langmuir realized, was to have as compact a filament as possible, a tightly coiled helix of wire, not a spread-out spiderweb. Such a tight coil could be made with tungsten, and in 1913, all this was put together: finely drawn tungsten wire, tightly coiled helices, in a bulb filled with argon. It was evident, at this point, that the days of the tantalum bulb were numbered, and that tungsten – tougher, cheaper, more efficient – would soon replace it (although this could not happen until after the war, when argon became available in commercial quantities). It was at this point that many manufacturers turned to making tungsten bulbs, and that Uncle Dave, with several of his brothers (and three of his wife’s brothers, the Wechslers, also chemists), pooled their resources and founded their firm, Turigstalite.

  Uncle Dave loved telling me this saga, much of which he had lived through himself, and its pioneers were heroes to him, not least because they had been able to combine a passion for pure science with strong practical and business sense (Langmuir, he told me, was the first industrial chemist ever to get a Nobel prize).

  Uncle Dave’s bulbs were larger than Osram, or GE, or other electric bulbs on the market – larger, heavier, and almost absurdly robust, and they seemed to last forever. Sometimes I longed for them to expire, so I could then smash them (not easy) and pull out the tungsten filaments and their molybdenum supports, and then have the pleasure of going to the triangular cupboard under the stairs to get a new, mint bulb, wrapped in its crinkled cardboard cylinder. Other people bought their electric bulbs one at a time, but we were sent cartons straight from the factory, a few dozen bulbs at a time – 60-watt and 100-watt bulbs for the most part, though we used little 15-watt bulbs for cupboards and night-lights, and a blazing 300-watt bulb as a beacon on the front porch. Uncle Tungsten made lightbulbs of all sorts and sizes, from dinky 1½-volt bulbs designed for little penlights to immense bulbs used for football fields or search-lights. There were also bulbs of special shapes, designed for instrument dials, ophthalmoscopes, and other medical instruments; and (despite Uncle’s attachment to tungsten) bulbs with filaments of tantalum for use in cinema projectors and on trains. Such filaments were less efficient, less capable of higher temperatures than tungsten, but more resistant to vibration. These, too, I liked to break open when they went pfft!, so I could extract the tantalum wire inside and add it to my growing stock of metals and chemicals.

  Uncle’s bulbs, and my taste for improvisation, incited me to set up a lighting system of my own inside the dark cupboard under the stairs. I had always been fascinated and slightly frightened by this space, which had no light of its own and seemed to disappear, in its furthest recesses, into secrecy and mystery. I used a 6-watt bulb, lemon-shaped, of the sort used in the sidelights of our car, and a 9-volt battery designed for an electric lantern. I put a switch, rather awkwardly, on the wall and ran wires from it to the bulb and the battery. I was absurdly proud of this little installation and made a point of showing it to visitors when they came to the house. But its glare penetrated the recesses of the cupboard, and in banishing the darkness, banished its mystery, too. Too much light, I decided, was not a good thing – there were some places best left with their secrets intact.

  CHAPTER SIX

  The Land of Stibnite

  I think I was somewhat a loner at my new school, The Hall, at least when I first came back to London. My friend Eric Korn, who had known me before the war – we were much the same age, and would both be taken to Brondesbury Park to play by our nannies – felt that something had happened to me. I had been aggressive and normal, he said, before the war, would pick fights, stand up for myself, speak my mind; where now I seemed intimidated, timid, did not start fights or conversations, withdrew, kept my distance. I did indeed keep a distance, in almost all ways, from the school. For I was fearful of more bullying or beating, and slow to realize that school could be a good place. But I was persuaded (or forced – I can no longer remember) to join the Cub Scouts. This, it was felt, would be good for me, would make me mix with others of my own age, teach me ‘needed’ skills for the outdoor life, like making a fire, camping, tracking – though it was not quite clear how such skills would be deployed in urban London. And for some reason, I never really learned them. I had no sense of direction, and no visual memory – when we played Kim’s Game, memorizing an array of different objects, I was so bad that there was some thought I might be mentally defective. Fires I laid could never be started, or went out within a few seconds; my attempts at making fire by rubbing two sticks together never succeeded (though I was able to conceal this, for some time, by borrowing my brother’s cigarette lighter); and my attempts to pitch a tent caught universal mirth.

  The only things I really liked about the Cub Scouts were the fact that we all wore the same uniform (which reduced my self-consciousness, my sense of being different), the invocations to Akela the grey wolf, and our identification with the wolf cubs in The Jungle Book – a gentle founding myth that pleased my romantic side. But the actual scout life, with me at least, continually miscarried in all sorts of ways.

  This came to a head one day when we were asked to make a special damper like those made by Baden-Powell, the founder of the Scouts, on his sojourn in Africa. Dampers, I understood, were hard, baked discs of unleavened flour, but when I sought for flour in our kitchen I found the flour bin, as it happened, empty. I did not want to ask if there was more flour, or go out and buy some – after all, we were supposed to be resourceful and self-sufficient – so I looked around further, and then, to my pleasure, discovered some cement outside, left by builders who had been constructing a wall. I cannot now reconstruct the mental process by which I persuaded myself that cement would do instead of flour, but I used the cement, made it into a paste, flavored it (with garlic), shaped it into a damperlike oval, and baked it in the oven. It became hard, very hard – but then dampers were very hard. When I brought it to the Cub meeting the next day, and handed it to Mr. Baron, the scoutmaster, he was astonished, but (I think) gratified, or intrigued, by its weight, the unusually heavy nourishment it promised. He put it into his mouth and sank his teeth into it, and was rewarded with a loud cracking as one of his teeth broke. He instantly spat the thing out; there were one or two twitters, and then an awful silence: everyone in the wolf pack looked at me.

  ‘How did you make the damper, Sacks?’ Mr. Baron asked, his voice menacingly quiet. ‘What did you put in it?’

  ‘I put cement, sir,’ I said, ‘I couldn’t find any flour.’

  The silence deepened, extended; everything seemed to freeze in a sort of motionless tableau. Struggling to control himself, and (I think) not to hit me, Mr. Baron made a short, impassioned speech: I had seemed quite a nice boy, he said, decent enough, though shy, incompetent, and a terrible bungler, but this business of the damper now raised very deep questions – did I realize what I was doing, was it my intention to harm? I tried to say it was only a joke, but it was beyond me to get any words out. Was I just incredibly stupid, was I vicious, or perhaps insane? Whatever the case, I had grossly misbehaved, I had injured my master, betrayed the ideals of the wolf pack. I was not fit to be a Scout, and with this Mr. Baron summarily expelled me.

  The term ‘acting out’ had not yet been invented, but the concept was often discussed, not a mile from the school, in Anna Freud’s Hampstead Clinic, where she was seeing every sort of disturbed and delinquent behavior in youngsters who had been through traumatic evacuations.

  The Willesden Public Library was an odd triangular building set at an
angle to Willesden Lane, a short walk from our house. It was deceptively small outside, but vast inside, with dozens of alcoves and bays full of books, more books than I had ever seen in my life. Once the librarian was assured I could handle the books and use the card index, she gave me the run of the library and allowed me to order books from the central library and even sometimes to take rare books out. My reading was voracious but unsystematic: I skimmed, I hovered, I browsed, as I wished, and though my interests were already firmly planted in the sciences, I would also, on occasion, take out adventure or detective stories as well. My school, The Hall, had no science and hence little interest for me – our curriculum, at this point, was based solely on the classics. But this did not matter, for it was my own reading in the library that provided my real education, and I divided my spare time, when I was not with Uncle Dave, between the library and the wonders of the South Kensington museums, which were crucial for me throughout my boyhood and adolescence.

  The museums, especially, allowed me to wander in my own way, at leisure, going from one cabinet to another, one exhibit to another, without being forced to follow any curriculum, to attend to lessons, to take exams or compete. There was something passive, and forced upon one, about sitting in school, whereas in museums one could be active, explore, as in the world. The museums – and the zoo, and the botanical garden at Kew – made me want to go out into the world and explore for myself, be a rock hound, a plant collector, a zoologist or paleontologist. (Fifty years later, it is still natural history museums and botanical gardens I seek out whenever I visit a new city or country.)