Like Faraday, I started to see ‘lines of force’ everywhere. I already had battery-powered front and rear lamps on my bike, and now I got dynamo-powered lights as well. As the little dynamo whirred on the back wheel, I would think sometimes of the magnetic lines of force being cut as it whirred, and of the mysterious, crucial role of motion.
Magnetism and electricity had seemed at first completely separate; now they seemed to be linked, somehow, by motion. It was at this point that I turned to my ‘physics’ uncle, Uncle Abe, who explained that the relationship between electricity and magnetism (and the relationship of both to light) had indeed been made clear by the great Scottish physicist Clerk Maxwell.[37] A moving electrical field would induce a magnetic field near it, and this in turn would induce a second electrical field, and this another magnetic field, and so on. With these almost instantaneous mutual inductions, Maxwell envisaged, there would be, in effect, a combined electromagnetic field in extremely rapid oscillation, and this would expand in all directions, propagating itself as a wave motion through space. In 1865, Maxwell was able to calculate that such fields would propagate at 300,000 kilometers per second, a velocity extremely close to that of light. This was very startling – no one had suspected any relationship between magnetism and light; indeed, no one had any idea what light might be, although it was well understood that it was propagated as a wave. Now Maxwell suggested that light and magnetism were ‘affections of the same substance, and that light is an electromagnetic disturbance propagated through the field according to electromagnetic laws.’ After hearing this, I began to think of light differently – as electric and magnetic fields leapfrogging over each other with lightning speed, braiding themselves together to form a ray of light.
It followed, as a corollary, that any varying electric or magnetic field could give rise to an electromagnetic wave propagating in all directions. It was this, Abe said, that inspired Heinrich Hertz to look for other electromagnetic waves – waves, perhaps, with a much longer wavelength than visible light. He was able to do this, in 1886, by using a simple induction coil as a ‘transmitter’ and small coils of wire with tiny (a hundredth of a millimeter) spark gaps as ‘receivers.’
When the induction coil was set to sparking, he could observe, in the darkness of his lab, tiny secondary sparks in the small coils. ‘You switch on the wireless’, said Abe, ‘and you never think of the wonder of what’s actually happening. Think how it must have seemed on that day in 1886 when Hertz saw these sparks in the darkness and realized that Maxwell was right, and that something like light, an electromagnetic wave, was raying out from his induction coil in every direction.’
Hertz died as a very young man, and never knew that his discovery was to revolutionize the world. Uncle Abe himself was only eighteen when Marconi first transmitted radio signals across the English Channel, and he remembered the excitement of this, even greater than the excitement over the discovery of X-rays two years earlier. Radio signals could be picked up by certain crystals, especially crystals of galena; one would have to find the right spot on their surface by exploring them with a tungsten wire, a ‘cat’s whisker.’ One of Uncle Abe’s own early inventions was to make a synthetic crystal that worked even better than galena. Everyone still spoke of radio waves as ‘Hertzian waves’ at this point, and Abe had called his crystal Hertzite.
But the supreme achievement of Maxwell was to draw all electromagnetic theory together, to formalize it, to compress it, into just four equations. In this half-page of symbols, Abe said, showing the equations to me in one of his books, was condensed the whole of Maxwell’s theory – for those who could understand them. Maxwell’s equations revealed, for Hertz, the lineaments of ‘a new physics… like an enchanted fairyland’ – not only the possibility of generating radio waves, but a sense that the whole universe was crisscrossed by electromagnetic fields of every sort, reaching to the ends of the universe.
15. Home Life
Zionism played a considerable part on both sides of my family. My father’s sister Alida worked during the Great War as an assistant to Nahum Sokolov and Chaim Weitzmann, the leaders of Zionism in England at the time, and, with her gift for languages, was entrusted with the translation of the Balfour Declaration in 1917 into French and Russian, and her son Aubrey, even as a boy, was a learned and eloquent Zionist (and later, as Abba Eban, the first Israeli ambassador to the United Nations). My parents, as doctors with a large house, were expected to provide a venue, a hospitable place, for Zionist meetings, and such meetings often took over the house in my childhood. I would hear them from my bedroom upstairs – raised voices, endless argument, passionate poundings of the table – and every so often a Zionist, flushed with anger or enthusiasm, would barge into my room, looking for the loo.
These meetings seemed to take a lot out of my parents – they would look pale and exhausted after each one – but they felt a duty to host them. I never heard them talk between themselves about Palestine or Zionism, and I suspected they had no strong convictions on the subject, at least until after the war, when the horror of the Holocaust made them feel there should be a ‘National Home.’ I felt they were bullied by the organizers of these meetings, and by the gangsterlike evangelists who would pound at the front door and demand large sums for yeshivas or ‘schools in Israel.’ My parents, clearheaded and independent in most other ways, seemed to become soft and helpless in the face of these demands, perhaps driven by a sense of obligation or anxiety. My own feelings (which I never discussed with them) were passionately negative: I came to hate Zionism and evangelism and politicking of every sort, which I regarded as noisy and intrusive and bullying. I longed for the quiet discourse, the rationality, of science.
My parents were moderately orthodox in practice (though there was little discussion that I remember as to what anyone actually believed), but some of the family were extremely orthodox. It was said that my mother’s father would wake up at night if his yarmulke fell off, and that my father’s father would not even swim without his. Some of my aunts wore sheitls – wigs – and these gave an oddly youthful, sometimes mannequinlike appearance to them: Ida had a bright yellow one, Gisela a raven black one, and these remained unchanged even when my own hair, many years later, had started to turn grey.
My mother’s eldest sister, Annie, had gone to Palestine in the 1890s and founded a school in Jerusalem, a school for ‘English gentlewomen of the Mosaic persuasion.’ Annie was a woman of commanding presence. She was excessively orthodox, and (I suspect) believed herself to be on close personal terms with the Deity (as she was with the Chief Rabbi, the Mandate, and the Mufti, in Jerusalem).[38] She would arrive periodically in England with steamer trunks so enormous they needed six porters to lift them, and on her visits she would introduce an atmosphere of terrifying religious strictness in the house – my parents, less orthodox, were somewhat scared of her gimlet eye.
On one occasion – it was an oppressive Saturday in the tense summer of 1939 – I decided to ride my tricycle up and down Exeter Road near the house, but there was a sudden downpour and I got completely soaked. Annie wagged a finger at me, and shook her heavy head: ‘Riding on shabbas! You can’t get away with it’, she said. ‘He sees everything, He is watching all the time!’ I disliked Saturdays from this time on, disliked God, too (at least the vindictive, punitive God that Annie’s warning had evoked), and developed an uncomfortable, anxious, watched feeling about Saturdays (which persists, a little, to this day).
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,
When, early in 1918, a lady, unlike the stage Woman of Destiny in that she was neither tall, dark nor thin, was ushered, with an expression of equal good humour and resolution, into my office I immediately realized that a new planet had swum into my ken. Miss Annie Landau had been throughout the War exiled… from her beloved… girls’ school, and demanded to return to it immediately. To my miserable pleading that her school was in use as a military hospital she opposed a steely insistence: and very few minutes had elapsed before I had leased her the vast empty building known as the Abyssinian Palace. Miss Landau rapidly became very much more than the headmistress of the best Jewish girls’ school in Palestine. She was more British than the English… she was more Jewish than the Zionists – no answer from her telephone on the Sabbath, even by the servants. She had been friendly with the Turks and Arabs before the War; so that her generous hospitality was for many years almost the only neutral ground upon which British officials, ardent Zionists, Moslem Beys and Christian Effendis could meet on terms of mutual conviviality.