Born the son of a pharmacist, near Portland, Oregon, in 1901, Pauling was blessed with a healthy dose of self-confidence, which clearly helped his career. As a young graduate he spurned an offer from Harvard, preferring instead an institution that had started life as Throop Polytechnic but in 1922 was renamed the California Institute of Technology, or Caltech.55 Partly because of Pauling, Caltech developed into a major centre of science, but when he arrived there were only three buildings, surrounded by thirty acres of weedy fields, scrub oak, and an old orange grove. Pauling initially wanted to work in a new technique that could show the relationship between the distinctively shaped crystals into which chemicals formed and the actual architecture of the molecules that made up the crystals. It had been found that if a beam of X rays was sprayed at a crystal, the beam would disperse in a particular way. Suddenly, a way of examining chemical structure was possible. X-ray crystallography, as it was called, was barely out of its infancy when Pauling got his Ph.D., but even so he quickly realised that neither his math nor his physics were anywhere near good enough to make the most of the new techniques. He decided to go to Europe in order to meet the great scientists of the day: Niels Bohr, Erwin Schrödinger, Werner Heisenberg, among others. As he wrote later, ‘I had something of a shock when I went to Europe in 1926 and discovered that there were a good number of people around that I thought to be smarter than me.’56
So far as his own interest was concerned, the nature of the chemical bond, his visit to Zurich was the most profitable. There he came across two less famous Germans, Walter Heitler and Fritz London, who had developed an idea about how electrons and wave functions applied to chemical reactions.57 At its simplest, imagine the Following: Two hydrogen atoms are approaching one another. Each is comprised of one nucleus (a proton) and one electron. As the two atoms get closer and closer to each other, ‘the electron of one would find itself drawn to the nucleus of the other, and vice versa. At a certain point, the electron of one would jump to the new atom, and the same would happen with the electron of the other atom.’ They called this an ‘electron exchange,’ adding that this exchange would take place billions of times a second.58 In a sense, the electrons would be ‘homeless,’ the exchange forming the ‘cement’ that held the two atoms together, ‘setting up a chemical bond with a definite length.’ Their theory put together the work of Pauli, Schrödinger, and Heisenberg; they also found that the ‘exchange’ determined the architecture of the molecule.59 It was a very neat piece of work, but from Pauling’s point of view there was one drawback about this idea: it wasn’t his. If he were to make his name, he needed to push the idea forward. By the time Pauling returned to America from Europe, Caltech had made considerable progress. Negotiations were under way to build the world’s biggest telescope at Mount Wilson, where Hubble would work. A jet propulsion lab was planned, and T. H. Morgan was about to arrive, to initiate a biology lab.60 Pauling was determined to outshine them ad. Throughout the early 1930s he released report after report, all part of the same project, and all having to do with the chemical bond. He succeeded magnificently in building on Heitler and London’s work. His early experiments on carbon, the basic constituent of life, and then on silicates showed that the elements could be systematically grouped according to their electronic relationships. These became known as Pauling’s rules. He showed that some bonds were weaker than others and that this helped explain chemical properties. Mica, for example, is a silicate that, as all chemists know, splits into thin, transparent sheets. Pauling was able to show that mica’s crystals have strong bonds in two directions and a weak one in a third direction, exactly corresponding to observation. In a second instance, another silicate we all know as talc is characterised by weak bonds all around, so that it crumbles instead of splitting, and forms a powder.61
Pauling’s work was almost as satisfying for others as it was for him.62 Here at last was an atomic, electronic explanation of the observable properties of well-known substances. The century had begun with the discovery of fundamentals that applied to physics and biology. Now the same was happening in chemistry. Once more, knowledge was beginning to come together. During 1930–5, Pauling published a new paper on the bond every five weeks on average.63 He was elected to the National Academy of Sciences in America at thirty-two, the youngest scientist ever to receive that honour.64 For a time, he was so far out on his own that few other people could keep up. Einstein attended one lecture of his and admitted afterward that it was beyond him. Uniquely, Pauling’s papers sent to the Journal of the American Chemical Society were published unrefereed because the editor could think of no one qualified to venture an opinion.65 Even though Pauling was conscious of this, throughout the 1930s he was too busy producing original papers to write a book consolidating his research. Finally, in 1939 he published The Nature of the Chemical Bond. This revolutionised our understanding of chemistry and immediately became a standard text, translated into several languages.66 It proved crucial to the discoveries of the molecular biologists after World War II.
The fresh data that the new physics was producing had very practical ramifications that arguably have changed our lives far more directly than was at first envisaged by scientists mainly interested in fundamental aspects of nature. Radio, in use for some time, moved into the home in the 1920s; television was first shown in August 1928. Another invention, using physics, revolutionised life in a completely different way: this was the jet engine, developed with great difficulty by the Englishman Frank Whittle.
Whittle was the working-class son of a mechanic who lived on a Coventry housing estate. As a boy he educated himself in Leamington Public Library, where he spent all his spare time devouring popular science books about aircraft – and turbines.67 All his life Frank Whittle was obsessed with flight, but his background was hardly natural in those days for a university education, and so at the age of fifteen he applied to join the Royal Air Force as a technical apprentice. He failed. He passed the written examination but was blocked by the medical officer: Frank Whittle was only five feet tall. Rather than give up, he obtained a diet sheet and a list of exercises from a friendly PE teacher, and within a few months he had added three inches to his height and another three to his chest measurement. In some ways this was as impressive as anything else he did later in life. He was finally accepted as an apprentice in the RAE and although he found the barrack-room life irksome, in his second year as a cadet at Cranwell, the RAF college – at the age of nineteen – he wrote a thesis on future developments in aircraft design. It was in this paper that Whittle began to sketch his ideas for the jet engine. Now in the Science Museum in London, the paper is written in junior handwriting, but it is clear and forthright.68 His crucial calculation was that ‘a B oomph wind against a machine travelling at 6oomph at 120,000 feet would have less effect than a 2omph head wind against the same machine at 1,000 feet.’ He concluded, ‘Thus everything indicates that designers should aim at altitude.’ He knew that propellers and petrol engines were inefficient at great heights, but he also knew that rocket propulsion was suitable only for space travel. This is where his old interest in turbines resurfaced; he was able to show that the efficiency of turbines increased at higher altitudes. An indication of Whittle’s vision is apparent from the fact that he was contemplating an aircraft travelling at a speed of 500mph at 60,000 feet, while in 1926 the top speed of RAF fighters was 150 mph, and they couldn’t fly much above 10,000 feet.